A higher volume of fibrotic tissue on virtual histology prior to coronary stent implantation predisposes to more pronounced neointima proliferation.

PubMed

Haine, Steven; Wouters, Kristien; Miljoen, Hielko; Vandendriessche, Tom; Claeys, Marc; Bosmans, Johan; Vrints, Christiaan

2018-04-01

Since neointima smooth muscle cells (SMC) mainly originate from the vessel wall, we investigated whether atherosclerotic plaque composition influences subsequent in-stent neointima proliferation and restenosis. We performed intravascular ultrasound (IVUS) with virtual histology in 98 patients prior to elective bare-metal stent (BMS) implantation in de novo coronary artery lesions. Virtual histology variables pre-percutaneous coronary intervention (PCI) were related to in-stent neointima proliferation six months after implantation assessed as late luminal loss of 0.88 mm (interquartile range (IQR) 0.37-1.23 mm) on angiography and as maximal percentage area stenosis of 42% (IQR 33-59%) and percentage volume intima hyperplasia of 27% (IQR 20-36%) on IVUS. A ridge-trace based multiple linear regression model was constructed to account for multicollinearity of the virtual histology variables and was corrected for implanted stent length (18 mm, IQR 15-23 mm), stent diameter (3.0 mm, IQR 2.75-3.5 mm) and lesion volume (146 mm³, IQR 80-201 mm³) prior to PCI. Fibrous tissue volume prior to PCI (49 mm³, IQR 30-77 mm³) was significantly and independently related to late luminal loss (p = .038), maximal percentage area stenosis (p = .041) and percentage volume intima hyperplasia (p = .004). Neither absolute nor relative amounts of fibrofatty, calcified or necrotic core tissue appeared related to any of the restenosis parameters. Subgroup analysis after exclusion of acute coronary syndrome (ACS) patients yielded similar results. Lesions with more voluminous fibrotic tissue pre-PCI show more pronounced in-stent neointima proliferation, even after correction for lesion plaque volume.

Long-term clinical and angiographic results of Sirolimus-Eluting Stent in Complex Coronary Chronic Total Occlusion Revascularization: the SECTOR registry.

PubMed

Galassi, Alfredo R; Tomasello, Salvatore D; Costanzo, Luca; Campisano, Maria B; Barrano, Giombattista; Tamburino, Corrado

2011-10-01

Drug-eluting stents showed a better angiographic and clinical outcome in comparison with bare metal stent in chronic total occlusions (CTOs) percutaneous revascularization, however, great concerns still remain regarding the rate of restenosis and reocclusion in comparison with nonocclusive lesions. To evaluate angiographic and clinical outcomes after sirolimus-eluting stent (SES) implantation in the setting of a "real world" series of complex CTOs. From January 2006 to December 2008, 172 consecutive patients with 179 CTO lesions were enrolled into registry. Among these, successful recanalization was obtained in 144 lesions (80.4%) with exclusive SES implantation in 104 lesions. The 9-12 months angiographic follow-up was executed in 85.5% of lesions with evidence of angiographic binary restenosis in 16.8% of lesions. Total stent length and number of stent implanted were recognized as independent predictors of restenosis (odds ratio [OR] 4.7, 95% confidence interval [CI] 1.28-107.09, P = 0.02) and (OR 5.8, 95% CI 1.39-23.55, P = 0.01), respectively.The 2-year clinical follow-up showed rates of target lesion revascularization, non-Q wave myocardial infarction, and total major adverse cardiovascular events (MACEs) of 11.1%, 2%, and 13.1%, respectively. Cox proportional-hazard analysis showed diabetes as independent predictor of MACEs (hazard ratio [HR] 4.832; 95% CI, 0.730-0.861; P = 0.028). Data from this registry demonstrate the long-term efficacy and safety of SES implantation after complex CTOs recanalization. ©2011, Wiley Periodicals, Inc.

Newly designed "pieced" stent in a rabbit model of benign esophageal stricture.

PubMed

Liu, Jin; Shang, Liang; Liu, Ji-Yong; Qin, Cheng-Yong

2015-07-28

To investigate a newly designed stent and its dilatation effect in a rabbit model of benign esophageal stricture. Thirty-four New Zealand white rabbits underwent a corrosive injury in the middle esophagus for esophageal stricture formation. Thirty rabbits with a successful formation of esophageal strictures were randomly allocated into two groups. The control group (n = 15) was implanted with a conventional stent, and the study group (n = 15) was implanted with a detachable "pieced" stent. The study stent (30 mm in length, 10 mm in diameter) was composed of three covered metallic pieces connected by surgical suture lines. The stent was collapsed by pulling the suture lines out of the mesh. Two weeks after stricture formation, endoscopic placement of a conventional stent or the new stent was performed. Endoscopic extraction was carried out four weeks later. The extraction rate, ease of extraction, migration, complications, and survival were evaluated. Stent migration occurred in 3/15 (20%) animals in the control group and 2/15 (13%) animals in the study group; the difference between the two groups was not statistically significant. At the end of four weeks, the remaining stents were successfully extracted with the endoscope in 100% (11/11) of the animals in the study group, and 60% (6/10) of the animals in the control group; this difference was statistically significant (P < 0.05). There was no difference in the mean number of follow-up days between the control and study groups (25.33 vs 25.85). Minor bleeding was reported in five cases in the study group and four in the control group. There were no severe complications directly associated with stent implantation or extraction in either of the two groups. In this experimental protocol of benign esophageal strictures, the novel "pieced" stent demonstrated a superior removal rate with a similar migration rate compared to a conventional stent.

Experimental Study of Poly-l-Lactic Acid Biodegradable Stents in Normal Canine Bile Ducts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yamamoto, Kiyosei, E-mail: yamakiyo@zg7.so-net.ne.jp; Yoshioka, Tetsuya; Furuichi, Kinya

Purpose: This study was designed to clarify the advantages of biodegradable stents in terms of mucosal reaction and biodegradation after placement. We designed a biodegradable stent and assessed stent degradation and changes in the normal bile ducts of dogs. Methods: The biodegradable stent is a balloon-expandable Z stent consisting of poly-l-lactic acid (PLLA) with a diameter of 6 mm and a length of 15 mm. We assessed four groups of three beagle dogs each at 1, 3, 6, and 9 months of follow-up. After evaluating stent migration by radiography and stent and bile duct patency by cholangiography, the dogs weremore » sacrificed to remove the bile duct together with the stent. The bile duct lumen was examined macroscopically and histologically, and the stent degradation was examined macroscopically and by scanning electron microscopy (SEM). Results: Bile duct obstruction was absent and none of the stents migrated. Macroscopic evaluation showed moderate endothelial proliferation in the bile ducts at the implant sites at 3 and 6 months and a slight change at 9 months. Slight mononuclear cell infiltration was histologically identified at all time points and epithelial hyperplasia that was moderate at 3 months was reduced to slight at 6 and 9 months. Stent degradation was macroscopically evident in all animals at 9 months and was proven by SEM in two dogs at 6 months and in all of them at 9 months. Conclusions: Our results suggest that PLLA bioabsorbable stents seems to be useful for implantation in the biliary system with further investigation.« less

Development of tissue-engineered self-expandable aortic stent grafts (Bio stent grafts) using in-body tissue architecture technology in beagles.

PubMed

Kawajiri, Hidetake; Mizuno, Takeshi; Moriwaki, Takeshi; Ishibashi-Ueda, Hatsue; Yamanami, Masashi; Kanda, Keiichi; Yaku, Hitoshi; Nakayama, Yasuhide

2015-02-01

In this study, we aimed to describe the development of tissue-engineered self-expandable aortic stent grafts (Bio stent graft) using in-body tissue architecture technology in beagles and to determine its mechanical and histological properties. The preparation mold was assembled by insertion of an acryl rod (outer diameter, 8.6 mm; length, 40 mm) into a self-expanding nitinol stent (internal diameter, 9.0 mm; length, 35 mm). The molds (n = 6) were embedded into the subcutaneous pouches of three beagles for 4 weeks. After harvesting and removing each rod, the excessive fragile tissue connected around the molds was trimmed, and thus tubular autologous connective tissues with the stent were obtained for use as Bio stent grafts (outer diameter, approximately 9.3 mm in all molds). The stent strut was completely surrounded by the dense collagenous membrane (thickness, ∼150 µm). The Bio stent graft luminal surface was extremely flat and smooth. The graft wall of the Bio stent graft possessed an elastic modulus that was almost two times higher than that of the native beagle abdominal aorta. This Bio stent graft is expected to exhibit excellent biocompatibility after being implanted in the aorta, which may reduce the risk of type 1 endoleaks or migration. © 2014 Wiley Periodicals, Inc.

[Early results with a monorail-stent-balloon device for endovascular treatment of renal artery stenosis].

PubMed

Müller-Hülsbeck, S; Jahnke, T; Grimm, J; Behm, C; Hilbert, C; Frahm, C; Biederer, J; Brossmann, J; Heller, M

2002-03-01

To evaluate the technical feasibility of a new monorail-stent-balloon device for treatment of renal artery stenosis (RAS). During a study period of 18 months, 38 patients with proven RAS in 41 cases (hypertension n = 36, renal insufficiency n = 13) and indication for stenting (calicified ostial lesions n = 35, insufficient PTA n = 4, dissection n = 2) were enrolled into this prospective evaluation. Pre-mounted stents (Rx-Herculink(TM) 5 mm = 13, 6 mm = 34, 7 mm = 1) were implanted a transfemoral (n = 35) or transbrachial approach (n = 6). Mean grade and lengths of stenosis measured were 88 % plus minus 10 and 9 mm plus minus 5. Renal stent implantation was technically successful in all cases (100 %). In 7 cases a second stent had to be implanted to cover the entire lesion. The transstenotic pressure drop decreased from 88 mmHg plus minus 10 before to 1 mmHg plus minus 1.8 after the procedure. Remaining stenosis measured 0.7 % plus minus 4.2. Serum creatine levels decreased from 1.9 mm/dl to 1.5 mg/dl (n. s.), blood pressure decreased from 178/94 mmHg to 148/79 mmHg (p < 0.0001) after the intervention. Primary and secondary patency rates at 6 months were 72 % (Standard Error 9.8 %) and 77 (% (Standard Error 9.2 %), respectively. With the used monorail-stend-balloon device a technically easy, secure and exact renal stent placement is guaranteed, patency rates are similar to those described in the current literature.

The carina angle-new geometrical parameter associated with periprocedural side branch compromise and the long-term results in coronary bifurcation lesions with main vessel stenting only.

PubMed

Gil, Robert J; Vassilev, Dobrin; Formuszewicz, Radoslaw; Rusicka-Piekarz, Teresa; Doganov, Alexander

2009-12-01

The two main problems unresolved in coronary bifurcation stenting are periprocedural side branch compromise and higher restenosis at long term. The purpose of this study is to reveal the link between periprocedural side branch compromise and long-term results after main vessel stenting only in coronary bifurcations. Eighty-four patients formed the study population. The inclusion criteria were good-quality angiograms, with maximal between-branch angle opening, no overlap, permitting accurate angiographic analysis. Carina angle (alpha)-the distal angle between main vessel (MV) before bifurcation and side branch (SB)-was measured pre- and poststenting. Clinical follow-up 9-12 months was obtained with coronary angiography if needed. The patient population was high-risk with 33% diabetics and 84% two- and three-vessel disease. Ninety-five stents were implanted in 92 lesions, with three T-stenting cases. Drug-eluting stents were implanted in 54%. Kissing-balloon (KBI) or sequential inflation was performed in 35%. SB functional closure occurred in 17.4%, with independent predictors alpha < 40 degrees and diameter ratio MB/SB >1.22. After 12+/-4 months there were five myocardial infarctions (6%) and 13 (15%) target lesion revascularization procedures. Independent predictors of major cardiovascular events were carina angle <40 degrees , MB lesion length >8 mm, negative change of between-branch angle, DES usage, and KBI. Smaller carina angle with straightening of MV-main branch from stent implantation in coronary bifurcations predicted higher SB compromise, restenosis, and MACE rates during follow-up of 1 year.

Comparative study of the corrosion behavior of peripheral stents in an accelerated corrosion model: experimental in vitro study of 28 metallic vascular endoprostheses

PubMed Central

Paprottka, Karolin J.; Paprottka, Philipp M.; Reiser, Maximilian F.; Waggershauser, Tobias

2015-01-01

PURPOSE Clinical cases of stent-fractures show that corrosion behavior might play a role in these fractures. Implanted in vivo, especially in combination with other implanted foreign materials, these metallic products are exposed to special conditions, which can cause a process of corrosion. Here, we aimed to test the corrosion potential of stents made of different materials in an in vitro setting. METHODS A total of 28 peripheral stents of different materials (nitinol, cobalt-chromium-nickel, tantalum, V4A) and surface treatments (electropolish, mechanical polish, no polish) were tested in vitro. Corrosion was accelerated by applying a constant voltage of 3.5 V and amperage of 1.16 mA in 0.9% NaCl. RESULTS Nitinol stents showed the lowest susceptibility to corrosion and the longest period without damage. The Memotherm II® (BARD Angiomed®) was the only stent that showed neither macroscopic nor microscopic damages. The worst performing material was cobalt-chromium-nickel, which showed corrosion damages about ten times earlier compared to nitinol. Considering the reasons for termination of the test, nitinol stents primarily showed length deficits, while V4A and tantalum stents showed fractures. Cobalt-chromium-nickel stents had multiple fractures or a complete lysis in equal proportions. When placed in direct contact, nitinol stents showed best corrosion resistance, regardless of what material they were combined with. In terms of polishing treatments, electropolished stents performed the best, mechanical-polished stents and those without polishing treatment followed. CONCLUSION The analysis of corrosion behavior may be useful to select the right stent fulfilling the individual needs of the patient within a large number of different stents. PMID:26268301

Very late stent thrombosis in a bare-metal stent, 9 years after implantation.

PubMed

Almasswary, Adel A

2009-06-01

Very late bare-metal stent thrombosis occurring beyond one year after stenting is uncommon. We report a case of bare-metal stent thrombosis presenting as acute myocardial infarction. The patient's stent was implanted 9 years ago, however, he was not adherent to his antiplatelet therapy (aspirin). This case highlights the importance of antiplatelet therapy in patients with stents even many years after implantation.

[Stent implantation in the treatment of pharynx anastomotic stenosis after cervical esophageal resection: a case report].

PubMed

Zang, Chuanshan; Sun, Jian; Sun, Yan

2016-03-01

We report the treatment of one patient with pharynx anastomotic stenosis after cervical esophagealresection by stent implantation. The patient suffered from serious pharynx anastomotic stenosis after gastric-pha-ryngeal anastomosis. After balloon-dilatation,a domestic self-expanding Z-stents was implanted in the stricture ofthe esophagus under the X-rays. After stent implantation, the patient has been leading a normal life for threeyears. Balloon dilatation and stent implantation is an effective and safe method in the treatment of patients withpharynx anastomotic stenosis.

Stent implantation into the tracheo-bronchial system in rabbits: histopathologic sequelae in bare metal vs. drug-eluting stents.

PubMed

Sigler, Matthias; Klötzer, Julia; Quentin, Thomas; Paul, Thomas; Möller, Oliver

2015-12-01

Stent implantation into the tracheo-bronchial system may be life-saving in selected pediatric patients with otherwise intractable stenosis of the upper airways. Following implantation, significant tissue proliferation may occur, requiring re-interventions. We sought to evaluate the effect of immunosuppressive coating of the stents on the extent of tissue proliferation in an animal model. Bare metal and sirolimus-coated stents (Bx Sonic and Cypher Select, Johnson & Johnson, Cordis) were implanted into non-stenotic lower airways of New Zealand white rabbits (weight 3.1 to 4.8 kg). Three stents with sirolimus coating and six bare metal stents could be analyzed by means of histology and immunohistochemistry 12 months after implantation. On a macroscopic evaluation, all stents were partially covered with a considerable amount of whitish tissue. Histologically, these proliferations contained fiber-rich connective tissue and some fibromuscular cells without significant differences between both stent types. The superficial tissue layer was formed by typical respiratory epithelium and polygonal cells. Abundant lymphocyte infiltrations and moderate granulocyte infiltrations were found in both groups correspondingly, whereas foreign-body reaction was more pronounced around sirolimus-eluting stents. After stent implantation in the tracheo-bronchial system of rabbits, we found tissue reactions comparable to those seen after stent implantation into the vascular system. There was no difference between coated and uncoated stents with regard to quality and quantity of tissue proliferation. We found, however, a significantly different inflammatory reaction with a more pronounced foreign-body reaction in sirolimus-coated stents. In our small series, drug-eluting stents did not exhibit any benefit over bare metal stents in an experimental setting.

The conical stent in coronary artery improves hemodynamics compared with the traditional cylindrical stent.

PubMed

Yu, Yi; Zhou, Yujie; Ma, Qian; Jia, Shuo; Wu, Sijing; Sun, Yan; Liu, Xiaoli; Zhao, Yingxin; Liu, Yuyang; Shi, Dongmei

2017-01-15

This study sought to explore the efficacy of the conical stent implantation in the coronary artery by comparing the effects of cylindrical and conical stents on wall shear stress (WSS) and velocity of flow and fractional flow reserve (FFR). The traditional cylindrical stent currently used in the percutaneous coronary intervention (PCI) has a consistent diameter, which does not match the physiological change of the coronary artery. On the contrary, as a new patent, the conical stent with tapering lumen is consistent with the physiological change of vascular diameter. However, the effect of the conical stent implantation on the coronary hemodynamics remains unclear. The coronary artery, artery stenosis and two stent models were established by Solidworks software. All models were imported into the computational fluid dynamics (CFD) software ANSYS ICEM-CFD to establish the fluid model. After the boundary conditions were set, CFD analysis was proceeded to compare the effects of two stent implantation on the change of WSS, velocity of flow and FFR. Hemodynamic indexes including FFR, blood flow velocity distribution (BVD) and WSS were improved by either the cylindrical or the conical stent implantation. However, after the conical stent implantation, the change of FFR seemed to be slower and more homogenous; the blood flow velocity was more appropriate without any obvious blood stagnation and direction changes; the WSS after the conical stent implantation was uniform from the proximal to distal side of the stent. Compared with the cylindrical stent, the conical stent implantation in the coronary artery can make the changes of vascular hemodynamic more closer to the physiological condition, which can reduce the incidence of intra-stent restenosis and thrombosis, thus making it more suitable for PCI therapy. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

The relationship between post-stent strut apposition and follow-up strut coverage assessed by a contour plot optical coherence tomography analysis.

PubMed

Kim, Jung-Sun; Ha, Jinyong; Kim, Byeong-Keuk; Shin, Dong-Ho; Ko, Young-Guk; Choi, Donghoon; Jang, Yangsoo; Hong, Myeong-Ki

2014-06-01

This study sought to evaluate the relationship between post-stent strut apposition and follow-up strut coverage using contour plot optical coherence tomographic analysis. Tracking the fate of interested regions of struts at different time points has not been investigated. Post-intervention and 6-month follow-up optical coherence tomographic evaluations were performed in 82 patients treated with biolimus- (n = 37) or sirolimus-eluting stents (n = 45). Post-stent apposition was classified as embedded, apposed, or malapposed. For volumetric stent evaluation, the post-intervention strut-artery distance and the neointimal thickness at follow-up were measured as a function of the circumferential arc length and longitudinal stent length. Computer-generated contour plots of the strut-artery distance and neointimal thickness were compared. The percentages of embedded and malapposed struts after intervention were 1.8% (Interquartile range [IQR]: 0.6% to 6.2%) and 2.3% (IQR: 0.5% to 5.2%), respectively. The percentages of uncovered and malapposed struts at 6 months were 16.0% (IQR: 7.4% to 33.3%) and 0% (IQR: 0% to 0.7%), respectively. The percentage of uncovered struts at 6 months varied significantly with post-stent strut apposition (0% [IQR: 0% to 11.4%] in embedded, 16.3% [IQR: 8.1% to 31.3%] in apposed, and 26.8% [IQR: 0% to 56.3%] in malapposed, p < 0.001 for all pairwise comparisons). In lesions without tissue prolapse, embedded struts were all covered (100% covered struts) compared with those with tissue prolapse (76.8% covered, p < 0.001). The optical coherence tomography-guided optimization of stent strut apposition enhances strut coverage at follow-up. This comprehensive method for evaluating strut apposition may provide more useful information to understanding the serial changes in strut coverage. (Neointimal Coverage After Implantation of Biolimus Eluting Stent With Biodegradable Polymer: Optical Coherence Tomographic Assessment According to the Treatment of Dyslipidemia and Hypertension and the Types of Implanted Drug-Eluting Stents; NCT01502904). Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Three-month evaluation of strut healing using a novel optical coherence tomography analytical method following bioresorbable polymer everolimus-eluting stent implantation in humans: the TIMELESS study.

PubMed

Vesga, Boris; Hernandez, Hector; Moncada, Miguel; Gasior, Pawel; Higuera, Sergio; Dager, Antonio; Arana, Camilo; Delgado, Juan A; Généreux, Philippe; Maehara, Akiko; Granada, Juan F

2017-03-01

Bioresorbable polymer drug-eluting stent technologies have been considered to have the potential to enhance vascular healing by reducing polymer exposure to the vessel wall, potentially allowing the earlier discontinuation of dual antiplatelet therapy. At present, the early vascular healing response to this type of technologies is still unclear. The TIMELESS study is a multicenter, prospective, single-arm study that enrolled real-world patients undergoing percutaneous coronary intervention. All patients underwent Synergy stent implantation, which consists of a platinum-chromium platform coated with an ultra-thin abluminal bioabsorbable poly-D,L-lactide-co-glycolide polymer-eluting everolimus. A total of 37 patients were included in the study. The majority of the patients underwent percutaneous coronary intervention because of acute coronary syndromes. At 3 months, angiographic follow-up showed a percentage diameter of stenosis of 8.1±7.5% and an angiographic late loss of 0.03±0.24 mm. In all analyzed struts, less than 1% of struts were definitely uncovered or covered with fibrin, 12.5% (5.0-18.5%) showed evidence of partial coverage, and the remaining (∼85%) were fully covered. No stent thrombosis was observed up to 12 months of clinical follow-up. In a real-world population, the implantation of a bioresorbable polymer drug-eluting stent resulted in almost complete strut coverage throughout the entire stent length at 3 months. The clinical implications for antiplatelet therapy and outcomes should be investigated further.

Expansion of the Multi-Link Frontier™ Coronary Bifurcation Stent: Micro-Computed Tomographic Assessment in Human Autopsy and Porcine Heart Samples

PubMed Central

Kralev, Stefan; Haag, Benjamin; Spannenberger, Jens; Lang, Siegfried; Brockmann, Marc A.; Bartling, Soenke; Marx, Alexander; Haase, Karl-Konstantin; Borggrefe, Martin; Süselbeck, Tim

2011-01-01

Background Treatment of coronary bifurcation lesions remains challenging, beyond the introduction of drug eluting stents. Dedicated stent systems are available to improve the technical approach to the treatment of these lesions. However dedicated stent systems have so far not reduced the incidence of stent restenosis. The aim of this study was to assess the expansion of the Multi-Link (ML) Frontier™ stent in human and porcine coronary arteries to provide the cardiologist with useful in-vitro information for stent implantation and selection. Methodology/Principal Findings Nine ML Frontier™ stents were implanted in seven human autopsy heart samples with known coronary artery disease and five ML Frontier™ stents were implanted in five porcine hearts. Proximal, distal and side branch diameters (PD, DD, SBD, respectively), corresponding opening areas (PA, DA, SBA) and the mean stent length (L) were assessed by micro-computed tomography (micro-CT). PD and PA were significantly smaller in human autopsy heart samples than in porcine heart samples (3.54±0.47 mm vs. 4.04±0.22 mm, p = 0.048; 10.00±2.42 mm2 vs. 12.84±1.38 mm2, p = 0.034, respectively) and than those given by the manufacturer (3.54±0.47 mm vs. 4.03 mm, p = 0.014). L was smaller in human autopsy heart samples than in porcine heart samples, although data did not reach significance (16.66±1.30 mm vs. 17.30±0.51 mm, p = 0.32), and significantly smaller than that given by the manufacturer (16.66±1.30 mm vs. 18 mm, p = 0.015). Conclusions/Significance Micro-CT is a feasible tool for exact surveying of dedicated stent systems and could make a contribution to the development of these devices. The proximal diameter and proximal area of the stent system were considerably smaller in human autopsy heart samples than in porcine heart samples and than those given by the manufacturer. Special consideration should be given to the stent deployment procedure (and to the follow-up) of dedicated stent systems, considering final intravascular ultrasound or optical coherence tomography to visualize (and if necessary optimize) stent expansion. PMID:21814552

Coronary artery aneurysm after stent implantation: acute and long-term results after percutaneous treatment with a stent graft.

PubMed

Rubartelli, Paolo; Terzi, Giacomo; Borgo, Lorenzo; Giachero, Corinna

2002-03-01

A patient with unstable angina was treated with elective Palmaz-Schatz stent implantation on a focal stenosis of the left circumflex artery. One year later, a large (13 mm in diameter) coronary artery aneurysm was diagnosed at angiography in the stented site. Intravascular ultrasound examination confirmed the presence of a true aneurysm located at the proximal end of the stent. The aneurysm was successfully treated with a Jostent Graft (Jomed Implantate) consisting of two slotted tube stainless steel stents supporting a polytetrafluoroethylene tube. The stent graft was implanted under intravascular ultrasound guidance. The 18-month angiographic follow-up showed good patency of the stent graft and complete exclusion of the aneurysm.

Comparison of retrievable stents and permanent stents for Budd-Chiari syndrome due to obstructive inferior vena cava.

PubMed

Bi, Yonghua; Chen, Hongmei; Ding, Penxu; Ren, Jianzhuang; Han, Xinwei

2018-05-30

To compare long-term outcomes of retrievable stents and permanent stents for BCS due to long-segment obstructive IVC. Between July 2000 and August 2016, 42 patients with BCS due to long-segment obstructive IVC were treated with retrievable stents (RS) and 41 patients were treated with permanent stents (PS). The retrievable stents was removed eventually after thrombus disappeared. Patients were subsequently followed-up by color Doppler sonography or CT scanning. All retrievable stent placements were successfully, and 37 retrievable stents were retrieved 8 to 29 days later. Forty-two stents were implanted in PS Group. One failure retrieval of retrievable stents occurred, and two failures of cannulations were found in PS Group. Two deaths may procedure-related and died from acute pulmonary thromboembolism perioperatively. One patient developed acute cerebral infarction and recovered after treatment. In PS Group, minor complications were found in 3 patients. The length of IVC lesion segment, length and thickness of IVC thrombus decreased significantly, and diameter of retrocaval IVC and diaphragm IVC increased significantly in both groups. During follow up, 3 patients died from liver failure in RS Group and 2 patients died in PS Group. RS Group showed a significantly higher primary patency rate than PS Group. Cumulative 1-, 3-, and 5-year secondary patency rates were 95.2%, 89.6%, 89.6% in RS Group, and 100%, 96.6%, 96.6% in PS Group (p= 0.7109). Retrievable stents is effective for BCS due to long-segment obstructive IVC, with a higher primary patency rate. This article is protected by copyright. All rights reserved.

Broken Esophageal Stent Successfully Treated by Interventional Radiology Technique

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zelenak, Kamil, E-mail: zelenak@mfn.s; Mistuna, Dusan; Lucan, Jaroslav

2010-06-15

Esophageal stent fractures occur quite rarely. A 61-year-old male patient was previously treated for rupture of benign stenosis, occurring after dilatation, by implanting an esophageal stent. However, a year after implantation, the patient suffered from dysphagia caused by the broken esophageal stent. He was treated with the interventional radiology technique, whereby a second implantation of the esophageal stent was carried out quite successfully.

Long-term results of permanent metallic stent implantation in the treatment of benign upper urinary tract occlusion.

PubMed

Li, Xun; He, Zhaohui; Yuan, Jian; Zeng, Guohua; He, Yongzhong; Lei, Ming

2007-08-01

The management of complicated benign upper urinary tract occlusion is extremely challenging, especially in patients unable to undergo an open operative procedure. We report the long-term results of a permanent metallic stent for benign upper urinary tract occlusion. From October 1995 to December 1998, 13 patients (8 men and 5 women, with a mean age of 43 years) with benign upper tract occlusion have been treated by metallic stent implantation. All patients had a nephrostomy tube to relieve the obstruction and the average time of the nephrostomy tube stay was 27 months, ranging from 3 to 131 months. The average length of occlusion was 2.7 cm, ranging from 1 to 3.6 cm. Ultrasonography, urography, diuresis renography and urine culture were performed every 3 months after stent insertion. Ureteroscopy was done when needed. The mean follow-up was 92 months (12-132 months). Ureteral patency was achieved in six patients and assisted patency with a Double-J stent was achieved in three patients. In two patients the kidney had to be removed because of progressive malfunction and in two patients the metal stent had to be extracted with the Holmium: YAG laser, burning it down due to the uncontrollable pyonephrosis. In three patients the ipsilateral flank pain recurred. One of these patients experienced urine leakage due to the initial nephrostomy tract: a ureteroscopy revealed a complete hyperplastic urothelial response. Proximal stone formations were found in 2 patients and all were removed by percutaneous nephrolithotomy (PCNL). No stent migration or fragmentation was observed. The implantation of metal stent is a safe and effective treatment for benign upper urinary tract occlusion, and has satisfying long-term outcome in selected cases. A further investigation is needed for its impact on the urodynamics of upper urinary tract.

Low-profile stent placement with the monorail technique for treatment of renal artery stenosis: midterm results of a prospective trial.

PubMed

Müller-Hülsbeck, Stefan; Frahm, Christian; Behm, Charlotte; Schäfer, Phillip Jobst; Bolte, Hendrik; Heller, Martin; Jahnke, Thomas

2005-07-01

To determine feasibility, safety, and midterm patency of a monorail balloon stent device for the treatment of renal artery stenosis (RAS). During a period of 30 months, 47 patients (with severe hypertension, n=45; renal insufficiency, n=20) with 50 cases of RAS and indications for stent implantation (calcified ostial lesion, n=41; insufficient percutaneous transluminal angioplasty, n=6; dissection, n=3) were enrolled into the prospective evaluation. After predilation, 59 stents (Rx-Herculink 4 mm, n=2; 5 mm, n=19; 6 mm, n=35; 7 mm, n=3) were implanted under manometer control with use of the long-sheath technique (5 F; 6 F for 7-mm stents) via a femoral (n=44) or transbrachial approach (n=6). Parameters of hypertension and renal insufficiency were determined before and after the procedure and for a maximum of 18 months. Restenosis rate was determined with color duplex ultrasonography. Renal artery stent placement (mean diameter, 5.7 mm; mean length, 16 mm) was technically successful in all cases (100%). Mean blood pressure and serum creatinine level decreased from 177/93 mm Hg to 145/78 mm Hg and from 1.8 mg/dL to 1.5 mg/dL, respectively. Within 48 hours after the implantation, acute occlusions occurred in two patients, supposedly triggered by cholesterol embolization. Primary and primary assisted patency rates were 87% and 92% at 6 months and 75% and 84% at 18 months. Renal artery stent placement with the rapid-exchange monorail system is a safe procedure with promising patency rates. In combination with the long-sheath technique, adequate control of stent deployment is guaranteed during the entire intervention. The low profile of the device facilitates the use of small sheaths (5 F) to minimize access-site complications.

[Interventional catheter treatment of bypass graft stenosis: comparison of intracoronary stent implantation and balloon angioplasty].

PubMed

Heidland, U E; Heintzen, M P; Schoppmann, D; Michel, C J; Strauer, B E

2000-02-25

Balloon angioplasty of a stenosed bypass graft has a much higher risk of recurrent stenosis than dilatation of a stenosed native coronary artery. Intracoronary stent implantation has established itself as the better treatment of native coronary artery stenosis than conventional balloon angioplasty. However, there is still uncertainty whether intracoronary stent implantation in stenosed bypass vessels gives better long-term results than conventional balloon angioplasty. Results were retrospectively analyzed of unrandomized 224 primarily successful interventions--122 balloon dilatations and 102 stent implantations--performed between January 1996 and June 1998 on stenosed coronary bypass grafts, re-examined by coronary angiography an average of 6 months later. All but 11 patients were on combined aspirin and ticlopidine antiplatelet aggregation treatment. There was a significantly lower 6-month restenosis rate (30.4%) after stent implantation than after balloon dilatation (51.6%). The re-intervention rate was also significantly lower after stent implantation. These data suggest that stent implantation of stenosed coronary bypass grafts under cover of platelet-aggregation inhibition with aspirin and ticlopidine provides a lower restenosis and thus higher revascularization rate than conventional balloon dilatation.

Evaluation of the 4-French Pulsar-18 Self-expanding Nitinol Stent in Long Femoropopliteal Lesions.

PubMed

Lichtenberg, Michael; Hailer, Birgit; Kaeunicke, Matthias; Stahlhoff, Wilhelm-Friedrich; Boese, Dirk; Breuckmann, Frank

2014-01-01

To evaluate the patency and the freedom of target lesion revascularization of the 4-French Pulsar-18 self-expandable (SE) nitinol stent for the treatment of long femoropopliteal occlusive disease in a two-center, prospective, all-comers registry with a follow-up period of 12 months. This registry enrolled 36 patients with symptomatic femoropopliteal long lesions for recanalization and implantation of the 4-French Pulsar-18 SE nitinol stent. Routine follow-up examination including duplex ultrasound was performed after 6 and 12 months. Primary patency was defined as no binary restenosis on duplex ultrasound (Peak systolic velocitiy ration (PSVR) <2.5) and no target lesion revascularization was performed within 12 months' follow-up. No drug-eluting devices were allowed in this registry. Average lesion length of the femoropopliteal segment was 182.3 ± 51.8 mm. Mean stent implantation length was 181.5 ± 35.4 mm. Total occlusion was present in 46 of the 48 (95.8%) treated lesions. Involvement of popliteal segment I-III was present in 3 (6.3%) lesions. The primary patency after 6 and 12 months was 87.5% and 85.4%, respectively. The clinically driven overall freedom from target lesion revascularization (fTLR) was 89.6% after 6 months and 87.5% after 12 months. ABI, pain-free walking distance and Rutherford category, all improved significantly (P < 0.001) after 6 and 12 months. The primary patency rate in patients with diabetes (P = 0.18) and renal insufficiency (P = 0.3) was not significantly lower as compared to the overall primary patency. In this two-center, all-comers registry, the use of the Pulsar-18 SE nitinol stent for endovascular intervention of femoropopliteal disease with a mean lesion length of 182.3 ± 51.8 mm showed promising primary patency and fTLR rates after 6 and 12 months. Diabetes and renal insufficiency had no negative impact on the patency rate.

Alterations in regional vascular geometry produced by theoretical stent implantation influence distributions of wall shear stress: analysis of a curved coronary artery using 3D computational fluid dynamics modeling.

PubMed

LaDisa, John F; Olson, Lars E; Douglas, Hettrick A; Warltier, David C; Kersten, Judy R; Pagel, Paul S

2006-06-16

The success of stent implantation in the restoration of blood flow through areas of vascular narrowing is limited by restenosis. Several recent studies have suggested that the local geometric environment created by a deployed stent may influence regional blood flow characteristics and alter distributions of wall shear stress (WSS) after implantation, thereby rendering specific areas of the vessel wall more susceptible to neointimal hyperplasia and restenosis. Stents are most frequently implanted in curved vessels such as the coronary arteries, but most computational studies examining blood flow patterns through stented vessels conducted to date use linear, cylindrical geometric models. It appears highly probable that restenosis occurring after stent implantation in curved arteries also occurs as a consequence of changes in fluid dynamics that are established immediately after stent implantation. In the current investigation, we tested the hypothesis that acute changes in stent-induced regional geometry influence distributions of WSS using 3D coronary artery CFD models implanted with stents that either conformed to or caused straightening of the primary curvature of the left anterior descending coronary artery. WSS obtained at several intervals during the cardiac cycle, time averaged WSS, and WSS gradients were calculated using conventional techniques. Implantation of a stent that causes straightening, rather than conforms to the natural curvature of the artery causes a reduction in the radius of curvature and subsequent increase in the Dean number within the stented region. This straightening leads to modest skewing of the velocity profile at the inlet and outlet of the stented region where alterations in indices of WSS are most pronounced. For example, time-averaged WSS in the proximal portion of the stent ranged from 8.91 to 11.7 dynes/cm2 along the pericardial luminal surface and 4.26 to 4.88 dynes/cm2 along the myocardial luminal surface of curved coronary arteries as compared to 8.31 dynes/cm2 observed throughout the stented region of a straight vessel implanted with an equivalent stent. The current results predicting large spatial and temporal variations in WSS at specific locations in curved arterial 3D CFD simulations are consistent with clinically observed sites of restenosis. If the findings of this idealized study translate to the clinical situation, the regional geometry established immediately after stent implantation may predispose portions of the stented vessel to a higher risk of neointimal hyperplasia and subsequent restenosis.

Use of nitinol self-expandable stents in 26 dogs with tracheal collapse.

PubMed

Beranek, J; Jaresova, H; Rytz, U

2014-02-01

A study was designed to describe a novel approach to the treatment of tracheal collapse (TC) in dogs using self-expandable nitinol stents. Medical records were reviewed retrospectively for 26 client owned dogs in which nitinol stents were deployed. The entire length of trachea was supported independently of the extent of TC. Two overlapping stents were used instead of one in cases where one stent was not spanning the entire trachea adequately. The diameter of the cranial radiolucent portion of trachea, just behind the cricoid cartilage, was measured as a specific landmark to select the appropriate size of the stent. Two self-expandable nitinol stents were inserted in 9 of 26 dogs; the trachea in the rest of the cases was supported with only one stent. A follow up tracheoscopy was performed in 10 of 26 cases with recurrent clinical signs. Secondary tracheal stenosis in these cases was caused by stent fracture, granuloma or excessive stent shortening. Additional stents were placed successfully to expand the stenotic lumen. A support of the entire trachea may decrease risk of nitinol fracture at the end of the implant. Long term clinical improvement (25 of 26 dogs, 96 %) is comparable with the results of other studies.

Finite Element Analysis of the Implantation Process of Overlapping Stents

PubMed Central

Xu, Jiang; Yang, Jie; Sohrabi, Salman; Zhou, Yihua; Liu, Yaling

2017-01-01

Overlapping stents are widely used in vascular stent surgeries. However, the rate of stent fractures (SF) and in-stent restenosis (ISR) after using overlapping stents is higher than that of single stent implantations. Published studies investigating the nature of overlapping stents rely primarily on medical images, which can only reveal the effect of the surgery without providing insights into how stent overlap influences the implantation process. In this paper, a finite element analysis of the overlapping stent implantation process was performed to study the interaction between overlapping stents. Four different cases, based on three typical stent overlap modes and two classical balloons, were investigated. The results showed that overlapping contact patterns among struts were edge-to-edge, edge-to-surface, and noncontact. These were mainly induced by the nonuniform deformation of the stent in the radial direction and stent tubular structures. Meanwhile, the results also revealed that the contact pressure was concentrated in the edge of overlapping struts. During the stent overlap process, the contact pattern was primarily edge-to-edge contact at the beginning and edge-to-surface contact as the contact pressure increased. The interactions between overlapping stents suggest that the failure of overlapping stents frequently occurs along stent edges, which agrees with the previous experimental research regarding the safety of overlapping stents. This paper also provides a fundamental understanding of the mechanical properties of overlapping stents. PMID:28690712

Microfocal X-ray computed tomography post-processing operations for optimizing reconstruction volumes of stented arteries during 3D computational fluid dynamics modeling.

PubMed

Ladisa, John F; Olson, Lars E; Ropella, Kristina M; Molthen, Robert C; Haworth, Steven T; Kersten, Judy R; Warltier, David C; Pagel, Paul S

2005-08-01

Restenosis caused by neointimal hyperplasia (NH) remains an important clinical problem after stent implantation. Restenosis varies with stent geometry, and idealized computational fluid dynamics (CFD) models have indicated that geometric properties of the implanted stent may differentially influence NH. However, 3D studies capturing the in vivo flow domain within stented vessels have not been conducted at a resolution sufficient to detect subtle alterations in vascular geometry caused by the stent and the subsequent temporal development of NH. We present the details and limitations of a series of post-processing operations used in conjunction with microfocal X-ray CT imaging and reconstruction to generate geometrically accurate flow domains within the localized region of a stent several weeks after implantation. Microfocal X-ray CT reconstruction volumes were subjected to an automated program to perform arterial thresholding, spatial orientation, and surface smoothing of stented and unstented rabbit iliac arteries several weeks after antegrade implantation. A transfer function was obtained for the current post-processing methodology containing reconstructed 16 mm stents implanted into rabbit iliac arteries for up to 21 days after implantation and resolved at circumferential and axial resolutions of 32 and 50 microm, respectively. The results indicate that the techniques presented are sufficient to resolve distributions of WSS with 80% accuracy in segments containing 16 surface perturbations over a 16 mm stented region. These methods will be used to test the hypothesis that reductions in normalized wall shear stress (WSS) and increases in the spatial disparity of WSS immediately after stent implantation may spatially correlate with the temporal development of NH within the stented region.

Clinical Results and Mechanical Properties of the Carotid CGUARD Double-Layered Embolic Prevention Stent.

PubMed

Wissgott, Christian; Schmidt, Wolfram; Brandt-Wunderlich, Christoph; Behrens, Peter; Andresen, Reimer

2017-02-01

To report early clinical outcomes with a novel double-layer stent for the internal carotid artery (ICA) and the in vitro investigation of the stent's mechanical properties. A prospective single-center study enrolled 30 consecutive patients (mean age 73.1±6.3 years; 21 men) with symptomatic (n=25) or high-grade (n=5) ICA stenosis treated with the new double-layer carotid CGUARD Embolic Prevention System (EPS) stent, which has an inner open-cell nitinol design with an outer closed-cell polyethylene terephthalate layer. The average stenosis of the treated arteries was 84.1%±7.9% with a mean lesion length of 16.6±2.1 mm. In the laboratory, 8×40-mm stents where tested in vitro with respect to their radial force during expansion, the bending stiffness of the stent system and the expanded stent, as well as the collapse pressure in a thin and flexible sheath. The wall adaptation was assessed using fluoroscopy after stent release in step and curved vessel models. The stent was successfully implanted in all patients. No peri- or postprocedural complications occurred; no minor or major stroke was observed in the 6-month follow-up. The bending stiffness of the expanded stent was 63.1 N·mm 2 and (not unexpectedly) was clearly lower than that of the stent system (601.5 N·mm 2 ). The normalized radial force during expansion of the stent to 7.0 mm, consistent with in vivo sizing, was relatively high (0.056 N/mm), which correlates well with the collapse pressure of 0.17 bars. Vessel wall adaptation was harmonic and caused no straightening of the vessel after clinical application. Because of its structure, the novel CGUARD EPS stent is characterized by a high flexibility combined with a high radial force and very good plaque coverage. These first clinical results demonstrate a very safe implantation behavior without any stroke up to 6 months after the procedure.

Biomechanical analysis on stent materials used as cardiovascular implants

NASA Astrophysics Data System (ADS)

Kumar, Vasantha; Ramesha, C. M.; Sajjan, Sudheer S.

2018-04-01

Atherosclerosis is the most common cause of death in the world, accounting for 48% of all deaths in the world. Atherosclerosis, also known as coronary artery disease occurs when excess cholesterol attaches itself to the walls of blood vessels. Coronary stent implantation is one of the most important procedures to treating coronary artery disease such atherosclerosis. Due to its efficiency, flexibility and simplicity, the use of coronary stents procedures has increased rapidly. In order to have better output of stent implantation, it is needed to study and analyze the biomechanical behavior of this device before manufacturing and put into use. Biomaterials are commonly used for medical application in cardiovascular stent implantation. A biomaterial is a non-viable material used as medical implant, so it is intended to interact with biological system. In this paper, an explicit dynamic analysis is used for analyzing the biomechanical behavior of cardiovascular stent by using finite element analysis tool, ABAQUS 6.10. Results showed that a best suitable biomaterial for cardiovascular stent implants, which exhibits an outstanding biocompatibility and biomechanical characteristics will be aimed at which will be quite useful to the human beings worldwide.

Fiber-reinforced silicone for tracheobronchial stents: An experimental study.

PubMed

Vearick, Samanta Bianchi; Demétrio, Kétner Bendo; Xavier, Rogério Gastal; Moreschi, Alexandre Heitor; Muller, André Frotta; Sanches, Paulo Roberto Stefani; Dos Santos, Luis Alberto Loureiro

2018-01-01

A trachea is a tubular structure composed of smooth muscle that is reinforced with cartilage rings. Some diseases can cause sagging in smooth muscle and cartilaginous tissue. The end result is reduction (narrowing) of the trachea diameter. A solution to this problem is the use of tracheal stents, which are small tubular devices made of silicone. One is inserted into the trachea to prevent or correct its constriction. The purpose of tracheal stent use is to maintain cartilage support that would otherwise be lost in the airway. Current tracheal stent models present limitations in terms of shape and characteristics of the silicone used in their production. One of the most important is the large thickness of the wall, which makes its placement difficult; this mainly applies to pediatric patients. The wall thickness of the stent is closely related to the mechanical properties of the material. This study aims to test the reinforcement of silicone with three kinds of fibers, and then stents that were produced using fiber with the best compressive strength characteristics. Silicone samples were reinforced with polypropylene (PP), polyamide (PA), and carbon fiber (CF) at concentrations of 2% and 4% (vol%), which then underwent tensile strength and Shore A hardness testing. Samples with fiber showed good characteristics; surface analyses were carried out and they were used to produce stents with an internal diameter of 11 or 13mm and a length of 50mm. Stents underwent compression tests for qualitative evaluation. Samples with 2% and 4% CF blends showed the best mechanical performance, and they were used to produce stents. These samples presented similar compressive strengths at low deformation, but stents with a 4% CF blend exhibited improved compressive strength at deformations greater than 30-50% of their diameter (P ≤ 0.05). The addition of 2% and 4% CF blends conferred greater mechanical strength and resistance to the silicone matrix. This is particularly true at low deformation, which is the condition where the stent is used when implanted. In the finite element compression strength tests, the stent composite showed greater compression strength with the addition of fiber, and the results were in accordance with mechanical compression tests performed on the stents. In vivo tests showed that, after 30 days of post-implantation in sheep trachea, an inflammatory process occurred in the region of the trachea in contact with the stent composite and with the stent without fiber (WF). This response is a common process during the first few days of implantation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Coated and uncoated self-expanding metal stents for malignant stenosis in the upper GI tract: preliminary clinical experiences with Wallstents.

PubMed

Ell, C; Hochberger, J; May, A; Fleig, W E; Hahn, E G

1994-09-01

The clinical feasibility of self-expanding metal stents with respect to the technical success, complications, and reintervention rate should be tested. Five coated and 26 uncoated prototype Wallstents, especially designed for stenosis of the upper GI tract, were implanted in 23 patients. All patients with dysphagia suffered from inoperable tumor stenosis of the esophagus or the cardia. Stent implantation was performed under slight i.v. sedoanalgesia. Technical success was achieved in all 31 implanted stents. Forty-eight hr after implantation, dysphagia was improved in 21/23 patients. Acute problems observed within 1 wk were stent migration (1 patient, uncoated stent), oblique position of the stent (3 patients), epigastric or retrosternal pain (9 patients), insufficient stent expansion (4 patients), and pouch formation at the upper rim of the stent (4 patients). An uncomplicated follow-up (median 66 days, range 10-139 days) was seen in 12 patients (52%). Major problems in the follow-up period were stent migration in three patients (three coated stents, two stent migrations in one patient) and stent obstruction by tumor ingrowth/overgrowth and/or food impaction in eight patients (35%). Most of these problems could be successfully resolved by implantation of a second stent or electrocoagulation of overgrowing tumor tissue. By the 1st of March, 1994, three patients were still alive with a follow-up period of 530 days (median range, 336-880 days); 20 patients were decreased with a follow-up period of 70 days (median range, 3-374 days). Implantation of esophageal Wallstents is safe and has a low risk of acute complications and mortality for the patient. Early complications such as perforation and bleeding did not occur. Tumor ingrowth/overgrowth are the major reasons for the high reintervention rate in the follow-up period. Coated stents can resolve this problem, provided that stent migration can be avoided by improvement of the coating technology.

Drug-eluting stent thrombosis: results from the multicenter Spanish registry ESTROFA (Estudio ESpañol sobre TROmbosis de stents FArmacoactivos).

PubMed

de la Torre-Hernández, José M; Alfonso, Fernando; Hernández, Felipe; Elizaga, Jaime; Sanmartin, Marcelo; Pinar, Eduardo; Lozano, Iñigo; Vazquez, Jose M; Botas, Javier; Perez de Prado, Armando; Hernández, Jose M; Sanchis, Juan; Nodar, Juan M Ruiz; Gomez-Jaume, Alfredo; Larman, Mariano; Diarte, Jose A; Rodríguez-Collado, Javier; Rumoroso, Jose R; Lopez-Minguez, Jose R; Mauri, Josepa

2008-03-11

This study sought to assess the incidence, predictors, and outcome of drug-eluting stent(DES) thrombosis in real-world clinical practice. The DES thromboses in randomized trials could not be comparable to those observed in clinical practice, frequently including off-label indications. We designed a large-scale, nonindustry-linked multicentered registry, with 20 centers in Spain. The participant centers provided follow-up data for their patients treated with DES, reporting a detailed standardized form in the event of any angiography-documented DES-associated thrombosis occurring. Of 23,500 patients treated with DES, definite stent thrombosis(ST) developed in 301: 24 acute, 125 subacute, and 152 late. Of the late, 62 occurred >1 year(very late ST). The cumulative incidence was 2% at 3 years. Antiplatelet treatment had been discontinued in 95 cases(31.6%). No differences in incidences were found among stent types. Independent predictors for subacute ST analyzed in a subgroup of 14,120 cases were diabetes, renal failure, acute coronary syndrome, ST-segment elevation myocardial infarction, stent length, and left anterior descending artery stenting, and for late ST were ST-segment elevation myocardial infarction, stenting in left anterior descending artery, and stent length. Mortality at 1-year follow-up was 16% and ST recurrence 4.6%. Older age, left ventricular ejection fraction <45%, nonrestoration of Thrombolysis In Myocardial Infarction flow grade 3, and additional stenting were independent predictors for mortality. The cumulative incidence of ST after DES implantation was 2% at 3 years. No differences were found among stent types. Patient profiles differed between early and late ST. Short-term prognosis is poor, especially when restoration of normal flow fails.

Histological Evaluation of a Self-Expanding Stent-Graft 23 Months After Implantation in the Superficial Femoral Artery.

PubMed

Ishihara, Takayuki; Iida, Osamu; Inoue, Katsumi; Fujita, Masashi; Masuda, Masaharu; Okamoto, Shin; Nanto, Kiyonori; Kanda, Takashi; Tsujimura, Takuya; Sunaga, Akihiro; Mano, Toshiaki; Uematsu, Masaaki

2017-10-01

To report histological examination of a Viabahn stent-graft implanted in the superficial femoral artery (SFA) for nearly 2 years. A 78-year-old man with peripheral artery disease was treated successfully with a 6.0×250-mm Viabahn self-expanding stent-graft in the right SFA, relieving his lower limb claudication. The patient died suddenly due to acute myocardial infarction 23 months later. Histological evaluation of the stent-graft implantation site revealed moderate neointimal proliferation at both proximal and distal edges of the device. In the middle part of the stent, significant macrophages and multinucleated foreign body giant cells had accumulated, although the stent was entirely patent. Furthermore, no endothelial cell coverage was found. Judging from these features, it might be necessary to continue dual antiplatelet therapy after stent-graft implantation over the long term to prevent thrombosis and subsequent restenosis or reocclusion.

Direct comparison of the short-term clinical performance of Z Guidant and Taxus stents.

PubMed

Guildford, Anna; Colombo, Paola; Bruschi, Giuseppe; Bonacina, Edgardo; Klugmann, Silvio; Santin, Matteo

2010-12-03

The recent introduction of drug-eluting stents in angioplasty of atherosclerotic blood vessels has significantly reduced the risks of in-stent restenosis (ISR) [1]. Indeed, it is known that in conventional stents ISR takes place in over 20% of the cases and up to 60% when implanted in diabetic patients. Conversely, clinical trials have shown that drug-eluting stents have significantly reduced ISR. Among the drug-eluting stents available on the market, Taxus stents (Tax, Boston Scientific, USA) are among the most used devices [2]. Tax are stainless-steel stents coated with Translute, a poly(styrene-b-isobutylene-b-styrene) polymer (PSIBS) eluting Placlitaxel, an anti-mitotic drug. Clinical trials on this type of drug-eluting stents have shown an incidence of restenosis of approximately 4%. The majority of these trials were randomized studies where conventional stents and drug-eluting devices have been implanted in separate patients' cohorts. Such a randomized design, although fundamental to collect statistically-relevant data, does not allow a direct histological comparison of different stent types when implanted in the same patient and do not show the individual susceptibility to the host response especially at short-term implantation times. Here, an interesting case study is presented where two chrome-cobalt stents (Z Guidant, ZG, Guidant Corp.) and a Tax have been simultaneously implanted in the same patient in three separate coronary arteries, retrieved after only 8 weeks and histologically analysed. Copyright © 2009 Elsevier Ireland Ltd. All rights reserved.

Transapical Aortic Valve Replacement under Real-time Magnetic Resonance Imaging Guidance: Experimental Results with Balloon-Expandable and Self-Expanding Stents

PubMed Central

Horvath, Keith A.; Mazilu, Dumitru; Kocaturk, Ozgur; Li, Ming

2010-01-01

Objective Aortic valves have been implanted on self-expanding (SE) and balloon-expandable (BE) stents minimally invasively. We have demonstrated the advantages of transapical aortic valve implantation (tAVI) under real-time magnetic resonance imaging (rtMRI) guidance. Whether there are different advantages to SE or BE stents is unknown. We report rtMRI guided tAVI in a porcine model using both SE and BE stents, and compare the differences between the stents. Methods Twenty-two Yucatan pigs (45-57kgs.) underwent tAVI. Commercially available stentless bioprostheses (21-25mm) were mounted on either BE platinum-iridium stents or SE nitinol stents. rtMRI guidance was employed as the intraoperative imaging. Markers on both types of stents were used to enhance the visualization in rtMRI. Pigs were allowed to survive and had follow-up MRI scans and echocardiography at 1, 3 and 6 months postoperatively. Results rtMRI provided excellent visualization of the aortic valve implantation mounted on both stent types. The implantation times were shorter with the SE stents (60±14 seconds) than BE (74±18s), (p=0.027). Total procedure time was 31 and 37 minutes respectively (p=0.12). It was considerably easier to manipulate the SE stent during deployment without hemodynamic compromise. This was not always the case with the BE stent and its placement occasionally resulted in coronary obstruction and death. Long-term results demonstrated stability of the implants with preservation of myocardial perfusion and function over time for both stents. Conclusions SE stents were easier to position and deploy thus leading to fewer complications during tAVI. Future optimization of SE stent design should improve clinical results. PMID:20971017

Endoscopic management of complications of self-expandable metal stents for treatment of malignant esophageal stenosis and tracheoesophageal fistulas.

PubMed

Bor, Renáta; Fábián, Anna; Bálint, Anita; Farkas, Klaudia; Szűcs, Mónika; Milassin, Ágnes; Czakó, László; Rutka, Mariann; Molnár, Tamás; Szepes, Zoltán

2017-08-01

Self-expandable metal stent (SEMS) implantation may rapidly improve the symptoms of malignant esophageal stenosis and tracheoesophageal fistulas (TEF). However, dysphagia often returns subsequently and repeated endoscopic intervention may be necessary. The aims of the study were to identify the risk factors of complications, and the frequency and efficacy of repeated endoscopic interventions; and to provide technical recommendations on appropriate stent selection. We analyzed retrospectively the clinical data of 212 patients with locally advanced esophageal cancer who underwent SEMS implantation. A total of 238 SEMS implantations were performed with 99.06% technical success and 1.26% procedure-related deaths in the enrolled 212 cases. Complications occurred in 84 patients (39.62%) and in 55 cases (25.94%) repeated endoscopic procedures were required. Early reintervention 24-48 h after the stent implantations was necessary due to stent migration (12 cases), arrhythmia (2 cases), intolerable retrosternal pain (1 case) and dyspnea (1 case). An average of 1.98 repeated gastroscopies (range 1-6; median 2), 13.58 weeks (range 1.5-48; median 11) after the stent implantation were performed during the follow-up period: 37 stent repositions, 23 restent implantations, 15 endoscopic esophageal dilations and 7 stent removals. In 48 cases (87.3%) oral feeding of patients was made possible by endoscopic interventions. In a quarter of SEMS implantations, complications occur that can be successfully managed by endoscopic interventions. Our experiences have shown that individualized stent choice may substantially reduce the complications rate and make repeated endoscopic interventions easier.

Randomized comparison of deliverability and in-hospital complications in implantation of BxSonic(R), Express(R), and Flexmaster(R) coronary stents.

PubMed

Thuesen, Leif; Galløe, Anders; Thayssen, Per; Rasmussen, Klaus; Kelbæk, Henning; Lassen, Jens Flensted; Hansen, Peter Riis; Pedersen, Knud Erik; Ravkilde, Jan; Helquist, Steffen; Abildgaard, Ulrik; Andersen, Henning Rud; Bøtker, Hans Erik; Kristensen, Steen Dalby; Hjort, Jacob; Krusell, Lars Romer

2005-11-01

To compare deliverability and in-hospital complications in implantation of BxSonic(R), Express(R), and Flexmaster(R) coronary stents in a randomized multicenter trial in five Danish interventional centres. Patients with planned stenting of at least one stenotic lesion in a native coronary artery were included in the study. There were 494 (664) patients (treated lesions) in the BxSonic(R), 499 (657) in the Express(R) and 500 (658) in the Flexmaster(R) groups. The groups were well matched with regard to age, sex, diabetes, smoking, hypercholesterolemia, hypertension, indication for PCI and coronary artery lesion complexity. The study stents were implanted with or without predilatation according to ordinary -clinical practice.Rates of successful stent implantation and in-hospital stent thrombosis, re-intervention, non-fatal myocardial infarction or death. The BxSonic(R), Express(R) and Flexmaster(R) stents were successfully implanted in 92,2%, 89,3% and 91,6% of all lesions (ns). There were no in-hospital deaths and the rates of in-hospital complications were similar in the three stent groups. We found similar deliverability and in-hospital complication rates of the BxSonic(R), Express(R) and Flexmaster(R) stents.

Edge-to-Edge Technique to Minimize Ovelapping of Multiple Bioresorbable Scaffolds Plus Drug Eluting Stents in Revascularization of Long Diffuse Left Anterior Descending Coronary Artery Disease.

PubMed

Rigatelli, Gianluca; Avvocata, Fabio Dell'; Ronco, Federico; Giordan, Massimo; Roncon, Loris; Caprioglio, Francesco; Grassi, Giuseppe; Faggian, Giuseppe; Cardaioli, Paolo

2016-06-01

Implantation of Drug Eluting Stents (DES) plus bioresorbable scaffolds (BVS) in very long diffuse left anterior descending coronary artery (LAD) disease may be problematic because of multiple devices overlapping. We sought to assess the short and mid-tern outcomes of combined implantation of DES and BVS using a novel "edge-to-edge" technique in patients with diffuse LAD disease. Patients with long diffuse LAD disease were enrolled in a prospective registry from 1st August 2014 to 1st August 2015 and treated with IVUS-aided percutaneous coronary intervention using a DES plus a single or multiple BVS using a novel "edge-to-edge" technique. Clinical follow up and invasive follow up driven by clinical justification was performed. Twenty-three patients (5 females, mean age 59.1± 9.1 years) were enrolled. Mean length of LAD disease was 73.1 ± 20.6 mm. Mean number of DES and BVS implanted was 1.2 ± 0.4 and 1.7 ± 1.3, respectively. At a mean follow-up of 11.3 ± 3.8 months, no stent thrombosis or MACE were observed. Angiographic and IVUS follow-up at a mean of 6.6 ± 0.7 months showed no significant angiographic restenosis and no appreciable stent gaps. In revascularization of long diffuse disease of the LAD, the edge-to-edge implantation technique appears to be feasible resulting in no restenosis or thrombosis on the short-term follow-up. (J Interven Cardiol 2016;29:275-284). © 2016, Wiley Periodicals, Inc.

MIGS: therapeutic success of combined Xen Gel Stent implantation with cataract surgery.

PubMed

Hohberger, Bettina; Welge-Lüßen, Ulrich-Christoph; Lämmer, Robert

2018-03-01

Glaucoma, a common disease in the elderly population, is frequently coexistent with cataract. While the combination of filtration surgery and cataract surgery is a challenging topic with limited success, minimal invasive glaucoma surgery (MIGS), such as Xen Gel Stents, seems to provide promising results. The aim of this study was to investigate the complete and qualified therapeutic success of Xen Gel Stent implantation with (XenPhaco) and without cataract surgery. One hundred and eleven open-angle glaucoma eyes underwent implantation of Xen45 Gel Stent (AqueSys, Inc.) with or without cataract operation. Complete therapeutic success was defined as target intraocular pressure (IOP) < 18 mmHg at any time point within 6 months of follow-up without local antiglaucomatous therapy or further surgical interventions. Qualified success was defined as target IOP <18 mmHg with additional 1-2 local antiglaucomatous eye drops. Failure included all cases with the necessity of at least three local antiglaucomatous eye drops or additional glaucoma surgery. Combined implantation of Xen Gel Stent with cataract surgery was performed in 30 eyes and stand-alone Xen Gel Stent implantation was performed in 81 eyes. A complete therapeutic success was achieved in 46.9% of single Xen Gel Stent implantation, whereas 53.3% was reached with combined XenPhaco. Qualified success was seen in 2.5% in the eyes of the single Xen Gel Stent implantation group and in 3.3% of the combined surgery group. Therapeutic failure rate was 49.4% in the stand-alone group vs 46.7% in the combined group. Data were not significantly different for group and subgroup analyses. Complete and qualified therapeutic success is similar for the combination of Xen Gel Stent implantation with and without cataract surgery in open-angle glaucoma patients. MIGS using Xen Gel Stent can be recommended in situations if glaucoma surgery is indicated besides coexisting cataract.

Nickel-free stainless steel avoids neointima formation following coronary stent implantation

PubMed Central

Fujiu, Katsuhito; Manabe, Ichiro; Sasaki, Makoto; Inoue, Motoki; Iwata, Hiroshi; Hasumi, Eriko; Komuro, Issei; Katada, Yasuyuki; Taguchi, Tetsushi; Nagai, Ryozo

2012-01-01

SUS316L stainless steel and cobalt–chromium and platinum–chromium alloys are widely used platforms for coronary stents. These alloys also contain nickel (Ni), which reportedly induces allergic reactions in some subjects and is known to have various cellular effects. The effects of Ni on neointima formation after stent implantation remain unknown, however. We developed coronary stents made of Ni-free high-nitrogen austenitic stainless steel prepared using a N2-gas pressurized electroslag remelting (P-ESR) process. Neointima formation and inflammatory responses following stent implantation in porcine coronary arteries were then compared between the Ni-free and SUS316L stainless steel stents. We found significantly less neointima formation and inflammation in arteries implanted with Ni-free stents, as compared to SUS316L stents. Notably, Ni2+ was eluted into the medium from SUS316L but not from Ni-free stainless steel. Mechanistically, Ni2+ increased levels of hypoxia inducible factor protein-1α (HIF-1α) and its target genes in cultured smooth muscle cells. HIF-1α and their target gene levels were also increased in the vascular wall at SUS316L stent sites but not at Ni-free stent sites. The Ni-free stainless steel coronary stent reduces neointima formation, in part by avoiding activation of inflammatory processes via the Ni-HIF pathway. The Ni-free-stainless steel stent is a promising new coronary stent platform. PMID:27877545

Nickel-free stainless steel avoids neointima formation following coronary stent implantation.

PubMed

Fujiu, Katsuhito; Manabe, Ichiro; Sasaki, Makoto; Inoue, Motoki; Iwata, Hiroshi; Hasumi, Eriko; Komuro, Issei; Katada, Yasuyuki; Taguchi, Tetsushi; Nagai, Ryozo

2012-12-01

SUS316L stainless steel and cobalt-chromium and platinum-chromium alloys are widely used platforms for coronary stents. These alloys also contain nickel (Ni), which reportedly induces allergic reactions in some subjects and is known to have various cellular effects. The effects of Ni on neointima formation after stent implantation remain unknown, however. We developed coronary stents made of Ni-free high-nitrogen austenitic stainless steel prepared using a N 2 -gas pressurized electroslag remelting (P-ESR) process. Neointima formation and inflammatory responses following stent implantation in porcine coronary arteries were then compared between the Ni-free and SUS316L stainless steel stents. We found significantly less neointima formation and inflammation in arteries implanted with Ni-free stents, as compared to SUS316L stents. Notably, Ni 2+ was eluted into the medium from SUS316L but not from Ni-free stainless steel. Mechanistically, Ni 2+ increased levels of hypoxia inducible factor protein-1 α (HIF-1 α ) and its target genes in cultured smooth muscle cells. HIF-1 α and their target gene levels were also increased in the vascular wall at SUS316L stent sites but not at Ni-free stent sites. The Ni-free stainless steel coronary stent reduces neointima formation, in part by avoiding activation of inflammatory processes via the Ni-HIF pathway. The Ni-free-stainless steel stent is a promising new coronary stent platform.

Three-year-old child with middle aortic syndrome treated by endovascular stent implantation.

PubMed

Moszura, Tomasz; Goreczny, Sebastian; Dryzek, Pawel; Niwald, Marek

2013-04-01

Middle aortic syndrome (MAS) is an extremely rare anomaly and represents both a diagnostic and therapeutic challenge, particularly in young children. A case of a 3.5 year-old child with MAS and arterial hypertension is reported, where owing to the patient's young age and the length of the hypoplastic aortic segment, surgical correction with end-to-end anastomosis was not feasible. Instead of palliative bypass grafting between the thoracic and abdominal aorta, successful percutaneous balloon angioplasty and stenting of the lesion was performed with the assistance of three-dimensional rotational angiography.

Immediate outcomes of eptifibatide therapy during intracoronary stent implantation.

PubMed

Shariati, Hooman; Sanei, Hamid; Pourmoghadas, Ali; Salehizadeh, Leila; Amirpour, Afshin

2016-01-01

The objective of the present study was to assess the major immediate outcomes of eptifibatide therapy during intracoronary stent implantation. In an interventional study, patients undergoing percutaneous coronary intervention (PCI) were randomized into either the eptifibatide ( n = 100) or the control ( n = 107) group. In each group, demographic and clinical characteristics such as cardiac death, stent thrombosis (ST), myocardial infarction (MI), rates of target lesion and vessel revascularization, cerebral vascular accident (CVA), and emergency coronary artery bypass grafting (CABG) were recorded. The overall rates of major adverse events such as mortality, Stent thrombosis (ST), Myocardial Infarction (MI), target lesion revascularization (TLR), target vessel revascularization (TVR), CVA, and emergency CABG within 24 h after stent implantation were low and comparable between the two groups; P > 0.05 considered significant for all comparisons. There were no statistical differences between the clinical outcomes of groups administered with single-dose intracoronary eptifibatide and control groups among patients undergoing PCI during stent implantation.

Periprocedural use of tirofiban in elective percutaneous coronary intervention for long coronary lesions in stable patients with overlapping drug-eluting stents--the PETITION study: a prospective, randomized, multicenter study.

PubMed

Zhang, Qi; Wang, Xiao Long; Liao, Min Lei; Hu, Jian; Yang, Zhen Kun; Ding, Feng Hua; Zhang, Jian Sheng; Du, Run; Zhu, Tian Qi; Shen, Wei Feng; Zhang, Rui Yan

2015-03-01

Patients are at risk of developing periprocedural myonecrosis after percutaneous coronary intervention (PCI). We investigated whether the use of the platelet glycoprotein (GP) IIb/IIIa receptor inhibitor tirofiban could reduce periprocedural myocardial infarction (PMI) in patients with stable coronary artery disease undergoing elective PCI with overlapping stent implantation for long lesions. A total of 748 stable angina patients with long lesions (≥ 40 mm in length) treated with overlapping stent implantation were randomly assigned to receive tirofiban (tirofiban group; n = 373) or conventional therapy (control group; n = 375). Intravenous tirofiban was initiated before PCI and maintained for 12 hr after the procedure. The primary endpoint was PMI, defined as an elevation in CK-MB > 3 times the upper limit of normal 12 hr after the index procedure. The secondary endpoint was major adverse cardiac events (MACE), including cardiac death, target vessel revascularization, and recurrent MI (re-MI), at one-year of clinical follow-up. The safety end-points included Thrombolysis in Myocardial Infarction (TIMI) major bleeding and stent thrombosis. Despite comparable angiographic and procedural characteristics, in the intention-to-treatment analysis, the primary endpoint was significantly reduced in the tirofiban group (4.0% vs. 11.5%, P < 0.001). Multivariate analysis revealed that the adjunctive use of tirofiban was the only negative predictor of PMI (OR 0.41, 95% CI 0.28-0.81, P < 0.01). At one-year of clinical follow-up, the overall occurrence of MACE was significantly lower in the tirofiban group (13.4% vs. 22.7%, P = 0.001). The rate of TIMI major bleeding and stent thrombosis did not differ significantly between the two groups. Our results show that the adjunctive use of tirofiban reduces the occurrence of PMI and MACE at one year in stable coronary artery disease patients undergoing elective PCI for long lesions with overlapping stent implantation. © 2015 Wiley Periodicals, Inc.

A new thermal shape memory Ti-Ni alloy stent covered with silicone.

PubMed

Nakamura, T; Shimizu, Y; Ito, Y; Matsui, T; Okumura, N; Takimoto, Y; Ariyasu, T; Kiyotani, T

1992-01-01

An attempt was made to develop an airway stent for nonsurgical transluminal implantation using a bronchofiberscope. The stent is composed of a single wire with a diameter of 0.5 mm. The wire is made of thermal shape memory titanium nickel alloy, with a transition temperature of 25-30 degrees C. To avoid direct contact between the metal and the tissue, the wire is covered with a 300 microns thick coating of silicone. The stent is horseshoe shaped in cross-section. It is 15 mm in outer transverse diameter and 40 mm long. Ten stents were implanted in 10 dogs whose tracheal cartilages had been previously broken. The stents were first cooled in ice water to reduce their diameter and then inserted into the target site. The wire was warmed to body temperature and recovered its initial shape within 10 sec. The dogs were killed for examination between 1 week and 6 months after implantation. All the stents were located at the implantation sites and were patent. Tissue reactions, such as ulceration and granulation formation, were less severe than in those with previously implanted non-silicone covered stents. Microscopic observation showed that the wires became gradually covered with epithelium within 2 months. This transluminal technique for preserving airway patency shows promise for clinical application.

Accuracy of a cone beam computed tomography-guided surgical stent for orthodontic mini-implant placement.

PubMed

Yu, Jae-Jung; Kim, Gyu-Tae; Choi, Yong-Suk; Hwang, Eui-Hwan; Paek, Janghyun; Kim, Seong-Hun; Huang, John C

2012-03-01

To validate the accuracy of a cone-beam computed tomography (CBCT)-guided surgical stent for orthodontic mini-implant (OMI) placement by quantitatively evaluating the difference between CBCT-prescribed and actual position of mini-implants in preoperative and postoperative CBCT images. A surgical stent was fabricated using Teflon-Perfluoroalkoxy, which has appropriate biological x-ray attenuation properties. Polyvinylsiloxane impression material was used to secure the custom-made surgical stent onto swine mandibles. CBCT scanning was done with the stent in place to virtually plan mini-implants using a three-dimensional (3D) software program. An appropriate insertion point was determined using 3D reconstruction data, and the vertical and horizontal angulations were determined using four prescribed angles. A custom-designed surveyor was used to drill a guide hole within the surgical stent as prescribed on the CBCT images for insertion of 32 OMIs. The mandibles with a surgical stent in place were rescanned with CBCT to measure the deviations between the virtual planning data and surgical results. The difference between the prescribed and actual vertical angle was 1.01 ± 7.25, and the horizontal difference was 1.16 ± 6.08. The correlation coefficient confirms that there was no intrarater variability in either the horizontal (R  =  .97) or vertical (R  =  .74) vectors. The surgical stent in this study guides mini-implants to the prescribed position as planned in CBCT. Since the statistical difference was not significant, the surgical stent can be considered to be an accurate guide tool for mini-implant placement in clinical use.

[Immediate and Long-term Results of the First in Russia of IntrocoronaryMetal Stent in the Coronary Artery].

PubMed

Babunashvili, A M; Navtsishvili, Z G; Konstantinov, B A

2016-02-01

The authors present immediate and long term results of the first in Russia implantation in coronary artery of Palmaz-Shatz metal stent. Indications for stenting were urgent after complicated dissection as a result of balloon dilation of discrete bifurcational stenosis of anterior interventricular artery (IVA). Immediate angiographic and clinical result was good. At control angiography after 13 years their was no restenosis in stented IVA. However novel narrowing was found in left main coronary artery (LMCA) in which drug eluting stent was implanted. Coronary angiography carried out after 7.5 years after stenting of LMCA and in 20 years after stent implantation in IVA revealed good patency of both stented segments without signs of restenosis. This case report demonstrates possibility of long term preservation of angiographic and clinical effect of staged endovascular treatment of coronary atherosclerosis.

Sex differences in the outcomes of stent implantation in mini-swine model.

PubMed

Kunio, Mie; Wong, Gee; Markham, Peter M; Edelman, Elazer R

2018-01-01

Sex-related differences have been noted in cardiovascular anatomy, pathophysiology, and treatment responses, yet we continued to drive evaluation of vascular device development in animal models without consideration of animal sex. We aimed to understand sex-related differences in the vascular responses to stent implantation by analyzing the pooled data of endovascular interventions in 164 Yucatan mini-swine (87 female, 77 male). Bare metal stents (BMS) or drug-eluting stents (DES) were implanted in 212 coronary arteries (63 single BMS implantation, 68 single DES implantation, 33 overlapped BMS implantation, and 48 overlapped DES implantation). Histomorphological parameters were evaluated from vascular specimens at 3-365 days after stent implantation and evaluated values were compared between female and male groups. While neointima formation at all times after implantation was invariant to sex, statistically significant differences between female and male groups were observed in injury, inflammation, adventitial fibrosis, and neointimal fibrin deposition. These differences were observed independently, i.e., for different procedure types and at different follow-up timings. Only subtle temporal sex-related differences were observed in extent and timing of resolution of inflammation and fibrin clearance. These subtle sex-related differences may be increasingly important as interventional devices meld novel materials that erode and innovations in drug delivery. Erodible materials may act differently if inflammation has a different temporal sequence with sex, and drug distribution after balloon or stent delivery might be different if the fibrin clearance speaks to different modes of pharmacokinetics in male and female swine.

Similarities and differences in coatings for magnesium-based stents and orthopaedic implants

PubMed Central

Ma, Jun; Thompson, Marc; Zhao, Nan; Zhu, Donghui

2016-01-01

Magnesium (Mg)-based biodegradable materials are promising candidates for the new generation of implantable medical devices, particularly cardiovascular stents and orthopaedic implants. Mg-based cardiovascular stents represent the most innovative stent technology to date. However, these products still do not fully meet clinical requirements with regards to fast degradation rates, late restenosis, and thrombosis. Thus various surface coatings have been introduced to protect Mg-based stents from rapid corrosion and to improve biocompatibility. Similarly, different coatings have been used for orthopaedic implants, e.g., plates and pins for bone fracture fixation or as an interference screw for tendon-bone or ligament-bone insertion, to improve biocompatibility and corrosion resistance. Metal coatings, nanoporous inorganic coatings and permanent polymers have been proved to enhance corrosion resistance; however, inflammation and foreign body reactions have also been reported. By contrast, biodegradable polymers are more biocompatible in general and are favoured over permanent materials. Drugs are also loaded with biodegradable polymers to improve their performance. The key similarities and differences in coatings for Mg-based stents and orthopaedic implants are summarized. PMID:27695671

Edge Stenosis After Covered Stenting for Long Superficial Femoral Artery Occlusive Disease: Risk Factor Analysis and Prevention With Drug-Coated Balloon Angioplasty.

PubMed

Lin, Ting-Chao; Huang, Chun-Yang; Chen, Po-Lin; Lee, Chiu-Yang; Shih, Chun-Che; Chen, I-Ming

2018-06-01

To report a retrospective analysis of risk factors for edge restenosis after Viabahn stent-graft treatment of superficial femoral artery (SFA) occlusive disease and determine any protective effect of drug-coated balloons (DCBs) used at the time of stent-graft implantation. Between October 2011 and July 2016, 110 patients (mean age 73.3±7.6 years; 78 men) were treated with the Viabahn stent-graft for long SFA occlusions. Thirty-eight (34.5%) patients had DCB reinforcement at the distal edge of the stent-graft. For analysis, the population was divided into groups of no edge stenosis patients (n=88; mean lesion length 22.4±4.2 cm) and edge stenosis patients (n=22; mean lesion length 23.5±5.7 cm). The clinical outcomes, ankle-brachial indices, computed tomography angiography findings, and patency were compared at a minimum of 12 months. Logistic regression analysis was employed to determine risk factors for edge stenosis; the results are presented as the odds ratio (OR) and 95% confidence interval. No differences in clinical or procedural characteristics were identified except the higher incidence of diabetes (p=0.008) and greater need for retrograde access (p=0.033) in the edge stenosis group. DCB reinforcement reduced the incidence of edge stenosis (p=0.021) and target lesion revascularization (TLR; p=0.010) and resulted in a significantly higher 1-year primary patency rate (92.1% vs 76.4%, p=0.042). However, multivariate analysis revealed only poor distal runoff (OR 0.31, 95% CI 0.11 to 0.83, p=0.020) as a predictor of edge stenosis. The risk of edge stenosis after Viabahn implantation was higher in patients with poor distal runoff. DCB reinforcement over the distal edge reduced edge stenosis, decreased 1-year TLR, and improved 1-year primary patency.

iStent as a Solo Procedure for Glaucoma Patients: A Systematic Review and Meta-Analysis.

PubMed

Malvankar-Mehta, Monali S; Chen, Yufeng Nancy; Iordanous, Yiannis; Wang, Wan Wendy; Costella, John; Hutnik, Cindy M L

2015-01-01

Glaucoma is a leading cause of irreversible blindness. It is firmly entrenched in the traditional treatment paradigm to start with pharmacotherapy. However, pharmacotherapy is not benign and has been well documented to have a number of significant challenges. Minimally invasive glaucoma surgery (MIGS) that targets the outflow pathway with minimal to no scleral dissection has resulted in the need to reconsider the glaucoma treatment paradigm. To perform a systematic review and meta-analysis to evaluate and quantify the effect on post-operative intraocular pressure (IOP) and number of topical glaucoma medications, in patients receiving the iStent MIGS device as the solo procedure without concurrent cataract surgery. A systematic review was conducted by searching various databases between January 1, 2000, and June 30, 2014. Studies reporting up to a maximum follow-up period of 24 months were retrieved and screened using the EPPI-Reviewer 4 gateway. Percentage reduction in IOP (IOPR%), and mean reduction in topical glaucoma medications after surgery were computed. Meta-analysis was performed using STATA v. 13.0. The standardized mean difference (SMD) was calculated as the effect size for continuous scale outcomes. Heterogeneity was determined using the I2 statistics, Z-value, and χ2 statistics. Fixed-effect and random-effect models were developed based on heterogeneity. Sub-group analysis was performed based on the number of iStents implanted and the follow-up period. The outcome measures were changes in the IOP and number of glaucoma medications. The search strategy identified 105 records from published literature and 9 records from the grey literature. Five studies with 248 subjects were included for quantitative synthesis. A 22% IOP reduction (IOPR%) from baseline occurred at 18-months after one iStent implant, 30% at 6-months after two iStents implantations, and 40% at 6-months after implantation of three iStents. A mean reduction of 1.2 bottles per patient of topical glaucoma medications occurred at 18-months after one iStent implant, 1.45 bottles per patient at 6-months after two iStents, and one bottle of medication per patient was reduced at 6-months following placement of three iStents implants. Meta-analysis results showed a significant reduction in the IOP after one iStent (SMD = -1.68, 95% CI: [-2.7, -0.61]), two iStents (SMD = -1.88, 95% CI: [-2.2, -1.56]), and three iStents (SMD = -2, 95% CI: [-2.62, -1.38]) implantation. Results showed a significant drop in the topical glaucoma medications after one iStent (SMD = -2.11, CI: [-3.95, -0.27]), two iStent (SMD = -1.88, CI: [-2.20, -1.56]), and three iStents (SMD = -2.00, CI: [-2.62, -1.38]) implantation. The maximum reduction in IOP occurred at 12-months (SMD = -2.21, CI: [-2.53, -1.88]) and a significant reduction in post-operative topical glaucoma medications occurred even after 18-months of iStent implantation (SMD = -0.71, CI: [-1.15, -0.26]). iStent implantation as a solo procedure without concurrent cataract extraction does lower IOP, and reduces the dependency on glaucoma medications. This effect seems to last at least 18 months.

Comparison of the endothelial coverage in everolimus and zotarolimus-eluting stents in normal, atherosclerotic, and bifurcation rabbit iliac arteries.

PubMed

Torii, Sho; Nakazawa, Gaku; Ijichi, Takeshi; Yoshikawa, Ayako; Ohno, Yohei; Ikari, Yuji

2018-01-01

The aim of this study is to evaluate differences in stent endothelial coverage among the second generation of drug-eluting stents. Incomplete stent coverage is one of the major causes of late stent thrombosis. Rabbits fed a normal diet received an everolimus (Xience Prime; EES) and a zotarolimus-eluting stent (Resolute Integrity; R-ZES) in each iliac artery, followed by sacrifice at 14 and 28 days after stent implantation. In addition, a group of atherosclerotic rabbits similarly received EES and R-ZES, and were sacrificed at 28 days. The extent of stent endothelial coverage was assessed by scanning electron microscopy. To evaluate endothelial coverage after bifurcation stenting, rabbits received EES and R-ZES placed with culotte stenting at the iliac bifurcation, followed by sacrifice at 14 and 28 days. In rabbits fed a normal diet, the percent uncovered strut area 14 days after stent implantation was significantly higher in R-ZES than in EES (10.1% (IQR 9.8-15.5) vs. 3.0% (IQR 1.5-9.7), p = 0.03), whereas it was not significantly different at 28-days (3.9% (IQR 0.8-10.3) vs. 1.0% (IQR 0.0-2.8), p = 0.2). In rabbits with induced atheroma, R-ZES also showed less endothelial coverage 28 days after stent implantation (5.3% (IQR 2.2-9.9) vs. 1.1% (IQR 0-6.2), p = 0.03). In the culotte stenting model, the percent uncovered strut area of the proximal overlapped segment was significantly higher in R-ZES at 14 days (15.8% (IQR 14.3-17.7) vs. 8.8% (IQR 8.3-9.8), p = 0.03) and 28 days (9.9% (IQR 4.1-13.9) vs. 2.5% (IQR 1.6-6.7), p = 0.04) after stent implantation. The carina area also showed a better coverage in EES compared with R-ZES. EES showed a better stent endothelial coverage compared with R-ZES after stent implantation in the early phase in normals, in arteries with lipid rich plaque, and in bifurcation stented sites.

Self-expanding stent made of polyester mesh with silicon coating (Polyflex) in the treatment of inoperable tracheal stenoses.

PubMed

Terra, Ricardo Mingarini; Minamoto, Helio; Tedde, Miguel Lia; Almeida, José Luiz Jesus de; Jatene, Fabio Biscegli

2007-01-01

To evaluate the Polyflex stent in terms of its efficacy, ease of implantation, and complications in patients with tracheobronchial affections. This was a prospective study, in which sixteen patients with inoperable tracheal stenosis secondary to orotracheal intubation (n = 12), neoplasia (n = 3), or Wegener's granulomatosis (n = 1) were monitored. Of these patients, eleven were women, and five were men. The mean age was 42.8 years (range, 21-72 years). Patients were submitted to implantation of a total of 21 Polyflex stents. All procedures were carried out in the operating room under general anesthesia, and the stents were implanted via suspension laryngoscopy using the stent applicator. Stents were implanted and symptoms were resolved in all cases. The stents remained in place for a mean period of 7.45 months, ranging from 2 to 18 months. The complications observed in the immediate postoperative period were dysphonia (in two patients, 12.5%) and odynophagia (in two patients, 12.5%). Late complications were cough (in ten patients, 62.5%), migration (in seven patients, 43.75%), granuloma formation (in two patients, 12.5%), and pneumonia (in one patient, 6.25%). The Polyflex stent is easily implanted, easily removed, well tolerated by patients and effective in resolving symptoms. However, its use is associated with a high rate of migration, especially in patients with post-orotracheal intubation stenosis.

Retrospective analysis of RF heating measurements of passive medical implants.

PubMed

Song, Ting; Xu, Zhiheng; Iacono, Maria Ida; Angelone, Leonardo M; Rajan, Sunder

2018-05-09

The test reports for the RF-induced heating of metallic devices of hundreds of medical implants have been provided to the U.S. Food and Drug Administration as a part of premarket submissions. The main purpose of this study is to perform a retrospective analysis of the RF-induced heating data provided in the reports to analyze the trends and correlate them with implant geometric characteristics. The ASTM-based RF heating test reports from 86 premarket U.S. Food and Drug Administration submissions were reviewed by three U.S. Food and Drug Administration reviewers. From each test report, the dimensions and RF-induced heating values for a given whole-body (WB) specific absorption rate (SAR) and local background (LB) SAR were extracted and analyzed. The data from 56 stents were analyzed as a subset to further understand heating trends and length dependence. For a given WB SAR, the LB/WB SAR ratio varied significantly across the test labs, from 2.3 to 11.3. There was an increasing trend on the temperature change per LB SAR with device length. The maximum heating for stents occurred at lengths of approximately 100 mm at 3 T, and beyond 150 mm at 1.5 T. Differences in the LB/WB SAR ratios across testing labs and various MRI scanners could lead to inconsistent WB SAR labeling. Magnetic resonance (MR) conditional labeling based on WB SAR should be derived from a conservative estimate of global LB/WB ratios. Published 2018. This article is a U.S. Government work and is in the public domain in the USA.

The trabecular bypass stent in a pseudophakic glaucoma patient: A 1-year follow-up

PubMed Central

Fea, Antonio M; Dogliani, Monica; Machetta, Federica; Lale-Lacroix, Gabriella; Brogliatti, Beatrice; Grignolo, Federico M

2008-01-01

Purpose To describe the 1-year success of a trabecular stent implant in a pseudophakic glaucoma patient. The stent is implanted through a small corneal incision under gonioscopic control. Intraocular pressure control was reported in cultured human anterior segment. Design Observational case report. Methods We report the case of a patient who was implanted and followed-up for 1 year at the Dipartimento di Fisiopatologia Clinica. The main outcome measures were intraocular pressure and visual field. Results The patient’s intraocular pressure was controlled with topical beta-blockers for 6 months and without therapy for 6 months. Two diurnal curves demonstrated achievement of target pressure during the day. The 1-year visual field was unchanged. Conclusions We are not aware of previous reports of trabecular stent implantation in pseudophakic patients. The trabecular stent had minimal peri-operative morbidity. Identification of the implantation site is challenging and reduction of efficacy over time may occur. PMID:19668446

Midterm to long-term safety and efficacy of self-expandable nitinol stent implantation for coarctation of aorta in adults.

PubMed

Haji Zeinali, Ali Mohammad; Sadeghian, Mohammad; Qureshi, Shakeel A; Ghazi, Payam

2017-09-01

Endovascular treatment of coarctation of aorta (CoA) by self-expandable Nitinol stents is one of the recognized treatment methods and may be an alternative to surgery or balloon-expandable stent implantation for CoA but there is little information about midterm to long term results of self-expandable stents. Sixty-two patients with CoA (40 men), with a mean age of 30.7 ± 11 years, (range 17-63 years) underwent stent implantation with Optimed self-expandable Nitinol stents between 2005 and 2014. Successful outcome was defined as peak systolic pressure gradient ≤20 mmHg after stent implantation. The patients were followed-up clinically and by echocardiography and in patients, in whom there was suspicion of recoarctation, CT angiography or recatheterization was performed. 65 stents were successfully implanted in all 62 patients. Peak systolic pressure gradient decreased from mean 62.4 ± 18 mmHg (range 35-100 mmHg) to mean 2.8 ± 5 mmHg (range 0-15 mmHg; P < 0.001). Stent displacement occurred in 3 patients during the procedure. These were managed successfully by an overlapping second stent. None of the patients had major complications such as aortic dissection, rupture, or vascular access problems. In follow up, only three patients had recoarctation, and two of these were managed successfully by balloon redilation or further stenting 16 and 18 months after the first procedure and one patient refused reintervention. There were two deaths, unrelated to the procedure, 12 and 78 months after the initial intervention. Follow-up of a mean of 45.5 ± 17 months (range 12-105 months) demonstrated no evidence of aneurysm formation or stent fracture. Self-expandable nitinol stents for the treatment of native and recurrent CoA is safe and has good efficacy with acceptable midterm to long-term outcome. © 2017 Wiley Periodicals, Inc.

Intracoronary stent implantation: new approach using a monorail system and new large-lumen 7F catheters from the brachial route.

PubMed

Jenny, D B; Robert, G P; Fajadet, J C; Cassagneau, B G; Marco, J

1992-04-01

In this brief report we describe a case of successful multivessel PTCA with intracoronary stent implantation using a new large-lumen 7F catheter from the left brachial approach. The application of this technique should be considered for intravascular stent implantation when anticoagulation ideally should not be interrupted or in anatomical situations limiting femoral vascular access.

A simple three-dimensional stent for proper placement of mini-implant

PubMed Central

2013-01-01

Background This paper deals with the fabrication of a three-dimensional stent which is simple in design but provides an accurate placement of a mini-implant in three planes of space, namely, sagittal (root proximity), vertical (attached gingiva/alveolar mucosa) and transverse (angulation). Findings The stent is made of 0.018 × 0.025 in. stainless steel archwire which consists of a ‘u loop’ angulated at 20°, a vertical limb, a horizontal limb and a stop. The angulation of the ‘u’ helps in the placement of the mini-implant at 70° to the long axis of the tooth. The vertical height is determined such that the mini-implant is placed at the mucogingival junction. The mini-implant is placed with the aid of the stent, and its angulation and proximity to the adjacent roots are checked with a cone beam computed tomography image. The cone beam computed tomography image showed the mini-implant at an angle of 70° to the long axis of the tooth. There is no contact between mini-implant and the roots of the adjacent teeth. Conclusion This stent is simple, easy to fabricate, cost-effective, and provides ease of insertion/removal, and three-dimensional orientation of the mini-implant. PMID:24326158

Nitinol Esophageal Stents: New Designs and Clinical Indications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Strecker, Ernst-Peter; Boos, Irene; Vetter, Sylvia

1996-11-15

Purpose: To evaluate the clinical use of covered and noncovered, knitted nitinol stents in patients presenting new stent indications. Methods: Self-expandable, knitted nitinol stents were implanted in four patients for treatment of dysphagia. In two patients who had malignant strictures and had esophago-respiratory fistulae and in one patient with an esophagocutaneous fistula, polytetrafluoroethylene (PTFE)-covered stents were implanted. One patient received a noncovered stent, but a retrograde approach through a percutaneous endoscopic gastrostomy (PEG) fistula had to be chosen for recanalization of an esophageal occlusion. Two patients received stents for treatment of benign strictures. Results: Recanalization of the stricture and stentmore » implantation were performed under fluoroscopic control without any procedure-related morbidity or mortality. Dysphagia improved in all patients and the esophageal fistulae could be sealed off by covered stents. During a maximum follow-up of 18 months, there was no stent migration or esophageal perforation. Complications observed were stent stenosis due to food impaction (1/4) and benign stent stenosis (2/2). Most complications could be treated by the interventional radiologist. Conclusion: Self-expandable, covered Nitinol stents provide an option for the treatment of dysphagia combined with esophageal fistulae. In combination with interventional radiology techniques, even complex strictures are accessible. For benign strictures, the value of stent treatment has not yet been proven.« less

Circulating endothelial progenitor cells are inversely correlated with in-stent restenosis in patients with non-ST-segment elevation acute coronary syndromes treated with EPC-capture stents (JACK-EPC trial).

PubMed

Wojakowski, W; Pyrlik, A; Król, M; Buszman, P; Ochała, A; Milewski, K; Smolka, G; Kawecki, D; Rudnik, A; Pawłowski, T; Jadczyk, T; Wyderka, R; Cybulski, W; Dworowy, S; Tendera, M

2013-06-01

Aim of the study was to evaluate the association between circulating endothelial progenitor cells (EPCs) and angiographic outcomes after implantation of GenousTM stent in patients with non-ST-segment elevation acute coronary syndromes (ACS) (NSTE-ACS) undergoing urgent percutaneous coronary intervention (PCI). Sixty patients treated with EPC-capture stent (N.=30) or bare metal stents (BMS) (N.=30) receiving 80 mg atorvastatin and dual antiplatelet therapy (DAT) for 12 months. Restenosis was assessed after 6 months by quantitative coronary angiography (QCA) and major acute coronary events (MACE) evaluated after 6 and 12 months. de novo lesion >70% in native vessel, diameter 2.5-4 mm, lesion length <30 mm. diabetes, previous revascularization, significant left main stenosis, chronic total occlusions (CTO) and multivessel disease. Majority of patients in EPC-capture stent and BMS groups presented with NSTEMI (73.3% and 70%, respectively). Mean stent length was 20.1±8 and 19.9±10 mm, diameter 3±0.97 and 3.1±0.88 mm in respective groups. The binary restenosis was significantly lower in GenousTM (13 vs. 26.6%, P=0.04). Risk of MACE after 6 and 12 months were comparable in both groups. There was no stent thrombosis. Numbers of circulating EPCs were significantly approximately 2-fold higher during the ACS than after 6 months. Mobilization of EPCs during acute ischemia was significantly lower in patients who developed restenosis after 6 months (3 vs. 4.5 cells/μL, P=0.002) and it was negatively correlated with late-loss after 6 months (R=-0.42; P<0.03). Use of GenousTM stents in NSTE-ACS is associated with lower restenosis rate than BMS at 6 months. There was no ST through 1 year. The number of circulating EPCs is inversely correlated with in-stent late loss (LL).

Clinical Study on Using 125I Seeds Articles Combined with Biliary Stent Implantation in the Treatment of Malignant Obstructive Jaundice.

PubMed

Wang, Tao; Liu, Sheng; Zheng, Yan-Bo; Song, Xue-Peng; Sun, Bo-Lin; Jiang, Wen-Jin; Wang, Li-Gang

2017-08-01

Aim: To study the feasibility and curative effect of 125 I seeds articles combined with biliary stent implantation in the treatment of malignant obstructive jaundice. Patients and Methods: Fifty patients with malignant obstructive jaundice were included. Twenty-four were treated by biliary stent implantation combined with intraluminal brachytherapy by 125 I seeds articles as the experimental group, while the remaining 26 were treated by biliary stent implantation only as the control group. The goal of this study was to evaluate total bilirubin, direct bilirubin and tumor markers (cancer antigen (CA)-199, CA-242 and carcinoembryonic antigen (CEA)), as well as biliary stent patency status and survival time before and after surgery. Results: Jaundice improved greatly in both groups. The decreases of CA-199 and CA-242 had statistical significance (p=0.003 and p=0.004) in the experimental group. The ratio of biliary stent patency was 83.3% (20/24) in the experimental group and 57.7% (15/26) in the control group (p=0.048). The biliary stent patency time in the experimental group was 1~15.5 (mean=9.84) months. The biliary stent patency time in the control group was 0.8~9 (mean=5.57) months, which was statistically significant (p=0.018). The median survival time was 10.2 months in the experimental group, while 5.4 months in control group (p<0.05). Conclusion: 125 I seeds articles combined with biliary stent implantation significantly prolongs biliary stent patency time and survival time for patients with malignant obstructive jaundice possibly by inhibiting the proliferation of vascular endothelial cells and the growth of tumor. Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

Very late stent thrombosis after sole stent-assisted coiling at the paraclinoid giant aneurysm : could prophylactic antiplatelet therapy be ceased at the only 1 year after procedure?

PubMed

Shin, Jung-Hoon; Park, Seong-Ho; Kim, Chang-Hyun; Lee, Chang-Young

2014-10-01

Stent thrombosis is a major limitation of stent-assisted coiling, which is an effective method for treating wide-necked aneurysms. Although early in-stent thrombosis has been reported, very late stent thrombosis (VLST) (>1 year) has not been reported following implantation of a single self-expandable stent designed for coiling. Herein, the authors present a case of VLST that occurred 14 months after single stent implantation in a large paraclinoid aneurysm with an ultra-wide neck involving the parent artery circumferentially. This case indicates the need for establishing guidelines regarding the optimal duration of prophylactic antiplatelet therapy following stent-assisted coiling, which remains undefined in the neuroendovascular field.

In-stent neoatherosclerosis and tissue characteristics of restenotic lesions following implantation of second generation drug-eluting stents in unrestricted coronary lesions: Optical frequency domain imaging study.

PubMed

Sabbah, Mahmoud; Kadota, Kazushige; El-Eraky, Azza; Kamal, Hanan M; Abdellah, Ahmed-Tageldien; El Hawary, Ahmed

2017-06-01

Differences in stent platform, polymer coatings, and antirestenotic drugs among the current in use second-generation drug-eluting stents (G2-DESs) may induce significant variations in neointimal response and vascular healing, which may impact the prevalence of neoatherosclerosis (NA) and morphological appearance of the restenotic tissue. Utilizing Optical frequency domain imaging, two independent reviewers, retrospectively compared the prevalence of neoatherosclerosis (NA), and the morphological differences, and tissue characteristics of 50 G2-DESs in-stent restenosis (ISR) lesions (35 everolimus-eluting stent [22 cobalt-chromium (CoCr), 13 platinum-chromium (PtCr)], and 15 biolimus-eluting stent [BES]) implanted liberally in unrestricted coronary lesions. More than half of the stents were implanted in type C lesions, while 40% of the stents were implanted primarily in lesions with recanalized chronic total occlusion. NA, defined as a neointima formation with the presence of lipids or calcification, was observed in fewer than half (24/50) of all ISR lesions with no significant in-between group differences (41%, 69%, and 40% in CoCr, PtCr, and BES respectively, P = 0.22), nor were there any significant differences in the morphological appearance or tissue characteristics between all G2-DESs subtypes. Acknowledging some limitations, our results may suggest that the prevalence of NA and the morphological appearance of restenotic lesions might not differ when G2-DESs are implanted in unrestricted, rather complex, coronary lesions. © 2017, Wiley Periodicals, Inc.

Satisfactory arterial repair 1 year after ultrathin strut biodegradable polymer sirolimus-eluting stent implantation: an angioscopic observation.

PubMed

Ishihara, Takayuki; Awata, Masaki; Iida, Osamu; Fujita, Masashi; Masuda, Masaharu; Okamoto, Shin; Nanto, Kiyonori; Kanda, Takashi; Tsujimura, Takuya; Uematsu, Masaaki; Mano, Toshiaki

2018-01-15

The ultrathin strut biodegradable polymer sirolimus-eluting stent (Orsiro, O-SES) exhibits satisfactory clinical outcomes. However, no report to date has documented the intravascular status of artery repair after O-SES implantation. We examined 5 O-SES placed in 4 patients (age 65 ± 12 years, male 75%) presenting with stable angina pectoris due to de novo lesions in native coronary arteries. Coronary angioscopy was performed immediately after percutaneous coronary intervention and 1 year later. Angioscopic images were analyzed to determine the following: (1) dominant grade of neointimal coverage (NIC) over the stent; (2) maximum yellow plaque grade; and (3) existence of thrombus. Yellow plaque grade was evaluated both immediately after stent implantation and at the time of follow-up observation. The other parameters were evaluated at the time of follow-up examination. NIC was graded as: grade 0, stent struts exposed; grade 1, struts bulging into the lumen, although covered; grade 2, struts embedded in the neointima, but translucent; grade 3, struts fully embedded and invisible. Yellow plaque severity was graded as: grade 0, white; grade 1, light yellow; grade 2, yellow; and grade 3, intensive yellow. Angioscopic findings at 1 year demonstrated the following: dominant NIC grade 1, grade 2, and grade 3 in 1, 2, and 2 stents, respectively; all stents were covered to some extent; focal thrombus adhesion was observed in only 1 stent. Yellow plaque grade did not change from immediately after stent implantation to follow-up. O-SES demonstrated satisfactory arterial repair 1 year after implantation.

Elective implantation of covered stents for coarctation and recoarctation in adolescents and adults.

PubMed

Alcibar, Juan; Blanco, Roberto; Fernandez, Luis; Arriola, Josune; Garcia, Koldobika; Peña, Natividad; Inguanzo, Ramón; Voces, Roberto; Castellanos, Enrique; Montes, Pedro M

2013-06-01

Stent implantation is an effective therapy for aortic coarctation and recoarctation. However, in adolescents and adults, aortic wall rupture and dissection can occur, as well as aneurysms during follow-up. In order to reduce these complications, we electively implant covered stents. Since 2005, we have performed the procedure using femoral access in 17 patients (2 adolescents and 15 adults), 16 electively and 1 as a rescue procedure. We used the Mullins technique in all cases, implanting a NuMED(®) covered stent. Good stent apposition was achieved in all 17 procedures; 8 patients required a distal flare. Gradient was reduced from 40 (16) mmHg to 2 (2) mmHg (P<.001) and lumen diameter increased from 4 (2) mm to 19 (3) mm (P<.001). Two exceptional cases are discussed: one patient with aortic wall rupture who underwent a rescue procedure using a stent within a covered stent and another patient with total obstruction and intercostal aneurysm in whom the outcome was fatal at 48 h postprocedure (autopsy is shown). Four-year clinical follow-up included Doppler echocardiography; an additional imaging technique was required in 13 patients. All patients recovered well and there were no complications. Covered stents are effective in treating coarctation and recoarctation in adolescents and adults, are the treatment of choice in patients with complex anatomy, and must be available in the operating room as a rescue device when implanting a conventional stent. Copyright © 2012 Sociedad Española de Cardiología. Published by Elsevier Espana. All rights reserved.

[Expandable metal mesh stents for treatment of tracheal stenoses and tracheomalacia].

PubMed

Müller, C; Dienemann, H; Hoffmann, H; Berger, H; Storck, M; Jolk, A; Schildberg, F W

1993-01-01

The treatment of tracheo-bronchial stenosis or tracheomalacia is mainly carried out by means of resection or tracheoplastic operative strategies. Since the introduction of metal-mesh stents, a definitive endoluminal therapy has to be considered under new aspects. Six patients with malignant stenosis or tracheomalacia due to compression were treated by implantation of Palmaz- or Wallstents. Immediately after the implantation, patients were relieved from dyspnoea, the forced inspiratory volume-1 (FIV1) was normalized. All implanted stents were well tolerated, even in the long-time follow-up (19 months). Bronchoscopic control showed overgrowth of the metal meshes by respiratory epithelium. The implantation of metal-mesh stents is an adequate alternative in the treatment of malignant stenosis and tracheomalacia.

Best Stent Length Predicted by Simple CT Measurement Rather than Patient Height.

PubMed

Barrett, Keith; Foell, Kirsten; Lantz, Andrea; Ordon, Michael; Lee, Jason Y; Pace, Kenneth T; Honey, R John D'A

2016-09-01

Ureteral stent length is important, as stents that are too long might worsen symptoms and too short are at higher risk of migration. The purpose of this study was to determine if patient or radiologic parameters correlate with directly measured ureteral length and if directly measured ureteral length predicts proper stent positioning. During stent placement, ureteral length (ureteropelvic junction to ureterovesical junction distance) was directly measured by endoscopically viewing a ureteral catheter (with 1-cm marking) emanating from the ureteral orifice. A 22, 24, or 26 cm stent was chosen to be closest to the measured ureteral length. For ureters >26 cm, a 26 cm stent was chosen. Ends of an "ideally positioned" stent were fully curled in the renal pelvis and bladder, without crossing the bladder midline. Rates of ideal stent position were compared between patients with matching stent and ureteral lengths and those with stent lengths differing by ≥1 cm (mismatched). The measured ureteral length was correlated with patient height, L1-L5 height, and length measured on CT. Fifty-nine ureters from 57 patients were included. Height was reasonably correlated with L1-L5 height (Spearman correlation coefficient [rho] = 0.79), although both were poorly correlated with directly measured ureteral length (rho = 0.18 for height and 0.32 for lumbar height). Ureteral lengths measured on CT correlated well with direct measurement (rho = 0.63 for axial cuts and rho = 0.64 for coronal cuts). Matched stent length was associated with higher rates of ideal stent position than mismatched (100% vs 70.9%, p = 0.006). CT measurements, rather than height, correlate well with measured length and could be used to choose the appropriate stent length. Stents matching directly measured ureteral lengths are associated with high rates of ideal stent position.

Accelerated Recovery of Endothelium Function after Stent Implantation with the Use of a Novel Systemic Nanoparticle Curcumin.

PubMed

Lu, Qi; Ye, Fang; Yang, Xiangjun; Gu, Qingqing; Wang, Peng; Zhu, Jianhua; Shen, Li; Gong, Feirong

2015-01-01

Curcumin was reported to exhibit a wide range of pharmacological effects including antioxidant, anti-inflammatory, and antiproliferative activities and significantly prevent smooth muscle cells migration. In the present study, a novel kind of curcumin loaded nanoparticles (Cur-NP) has been prepared and characterized with the aim of inhibiting inflammation formation and accelerating the healing process of the stented arteries. Cur-NP was administrated intravenously after stent implantation twice a week and detailed tissue responses were evaluated. The results demonstrated that intravenous administration of Cur-NP after stent implantation accelerated endothelial cells restoration and endothelium function recovery and may potentially be an effective therapeutic alternative to reduce adverse events for currently available drug eluting stents.

Memokath Stent Failure in Recurrent Bulbar Urethral Strictures: Results From an Investigative Pilot Stage 2A Study.

PubMed

Barbagli, Guido; Rimondi, Claudio; Balò, Sofia; Butnaru, Denis; Sansalone, Salvatore; Lazzeri, Massimo

2017-09-01

To evaluate the efficacy of the Memokath stent in managing recurrent bulbar urethral strictures. This is an investigative pilot stage 2A study in patients with a recurrent bulbar urethral stricture who underwent a Memokath stent implant from January 2014 to January 2016 in a single high-volume center for urethral reconstruction. The Memokath stent (Pnn Medical A/S, Kvistgaard, Denmark) was manufactured from nitinol, a biocompatible alloy of nickel and titanium, which was endoscopically placed. It had a 24-Fr outside diameter and was preloaded on a disposable delivery device. When correctly positioned, the stent was anchored by a warm water (55°C) instillation, which expanded the proximal end of the stent from 24 to 42 Fr .The stent was provided in lengths of 3-7 cm in 1-cm increments. Sixteen patients were included in the study. The median follow-up was 16 months. In 7 patients (43.7%), the stent was removed within 1 year. The main adverse events were pain, encrustations, stones, and recurrent strictures. Four patients (25%) were considered a success and 12 (75%) were failures. Study limitations include the small sample. The Memokath stent was deemed to be not clinically helpful and had significant side effects, and therefore should not be considered a treatment option for men with bulbar urethral strictures. Copyright © 2017 Elsevier Inc. All rights reserved.

Elastic Deformation Properties of Implanted Endobronchial Wire Stents in Benign and Malignant Bronchial Disease: A Radiographic In Vivo Evaluation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hautmann, Hubert; Rieger, Johannes; Huber, Rudolf M.

1999-03-15

Purpose: To evaluate the long-term mechanical behavior in vivo of expandable endobronchial wire stents, we imaged three different prostheses in the treatment of tracheobronchial disease. Methods: Six patients with bronchial stenoses (three benign, three malignant) underwent insertion of metallic stents. Two self-expandable Wallstents, two balloon-expandable tantalum Strecker stents and two self-expandable nitinol Accuflex stents were used. Measurements of deformation properties were performed during voluntary cough by means of fluoroscopy, at 1 month and 7-10 months after implantation. The procedures were videotaped, their images digitized and the narrowing of stent diameters calculated at intervals of 20 msec. Results: After stent implantationmore » all patients improved with respect to ventilatory function. Radial stent narrowing during cough reached 53% (Wallstent), 59% (tantalum Strecker stent), and 52% (nitinol Accuflex stent) of the relaxed post-implantation diameter. Stent compression was more marked in benign compared with malignant stenoses. In the long term permanent deformation occurred with the tantalum Strecker stents; the other stents were unchanged. Conclusion: Endobronchial wire stents can be helpful in the treatment of major airway collapse and obstructing bronchial lesions. However, evidence of material fatigue as a possible effect of exposure to recurrent mechanical stress on the flexible mesh tube may limit their long-term use. This seems to be predominantly important in benign bronchial collapse.« less

Biliary metal stents for proximal esophageal or hypopharyngeal strictures.

PubMed

Bechtler, Matthias; Wagner, Florian; Fuchs, Erik-Sebastian; Jakobs, Ralf

2015-11-01

Endoscopic dilation is the standard of care for stenoses of the cervical esophagus, but refractory strictures require some form of stenting. Most endoscopists avoid the placement of metal stents near the upper esophageal sphincter as they can cause major problems like severe cervical pain and globus sensation. We report our results with the use of biliary SEMS in the upper esophagus, which have a smaller diameter than regular esophageal stents and therefore exert less expansive force. We retrospectively reviewed all patients in our center between July 2011 and June 2014 who received a biliary metal stent because of a refractory stricture in the cervical esophagus. We implanted biliary SEMS (Wallflex, Boston Scientific) with a diameter of 1 cm and length of 6-8 cm. Technical and clinical success, adverse events and duration of stenting were evaluated. Ten patients were treated with biliary SEMS in the upper esophagus. Strictures were located between 10 and 19 cm from incisor teeth. Stent placement was successful in all (10/10) patients. One stent had to be extracted because of pain and globus sensation. Apart from that stent tolerability was good. All remaining patients (9/9) reported improvement of dysphagia with a decrease in mean dysphagia score from 3.2 to 1.78. Mean duration of stenting was 68 days. Because of a high clinical success rate and good tolerability, biliary metal stents are a reasonable alternative for difficult strictures in the cervical esophagus, especially in the palliative setting.

Flow Changes after Endovascular Treatment of a Wide-Neck Anterior Communicating Artery Aneurysm by using X-configured Kissing Stents (Cross-Kissing Stents) Technique

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zelenak, Kamil, E-mail: zelenak@unm.sk; Zelenakova, Jana; DeRiggo, Julius

2011-12-15

Endovascular treatment for a wide-neck anterior communicating artery (AcomA) aneurysm remains technically challenging. Stent-assisted embolization has been proposed as an alternative of treatment of complex aneurysms. The X-configuration double-stent-assisted technique was used to achieve successful coiling of wide-neck AcomA aneurysm. Implanted stent can alter intra-arterial flow. Follow-up angiograms 4 months later showed flow changes due to used X-technique of stents implantation and filling of the anterior cerebral artery from the opposite internal carotid artery.

Novel self-expandable, stent-based transcatheter pulmonic valve: a preclinical animal study.

PubMed

Kim, Gi Beom; Lim, Hong-Gook; Kim, Yong Jin; Choi, Eun Young; Kwon, Bo Sang; Jeong, Saeromi

2014-04-15

Because transcatheter implantation of pulmonary valve is indicated for limited-size dysfunctional right ventricular outflow tract only as a balloon-expandable stent, we investigated the feasibility of a large-diameter self-expandable valved stent and the durability of the valve after >6 months. We made a nitinol-wire-based, self-expandable valved stent with leaflets made from porcine pericardium. The porcine pericardium was treated with α-galactosidase, glutaraldehyde, and glycine after decellularization. After cutting the inguinal or cervical area, we implanted a valved stent in 12 sheep through the femoral or jugular vein by using an 18-Fr delivery catheter, controlling the catheter handles and hook block under fluoroscopic and echocardiographic guidance. The mean body weight of sheep was 43.9 kg. We successfully implanted valved stents (diameter: 24 mm in 7 sheep, 26 mm in 5 sheep) in good position in 8 sheep, in the main pulmonary artery (PA) in 2 sheep, and in the right ventricular outlet tract (RVOT) in 2 sheep. We sacrificed 8 sheep (6 sheep in good position, 1 sheep in the main PA, and 1 sheep in the RVOT) after >6 months. Five of the 6 sheep implanted in good position showed well-preserved valve morphology at the time of sacrifice. Histologic findings after routine sacrifice showed well-maintained collagen wave structure and no visible calcification in all explanted valve leaflets. Transcatheter implantation of a nitinol-wire-based, self-expandable valved stent in the pulmonic valve was feasible, and stents implanted in good position showed well-preserved valve leaflets with functional competence in the mid-term results. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

A Feasibility Study of a New Unibody Branched Stent Graft Applied to Reconstruct the Canine Aortic Arch.

PubMed

Li, W; Zhai, S; Xu, K; Li, Q; Zhong, H; Li, T; Zhang, Z

2018-06-01

The aim was to evaluate the feasibility and safety of a new unibody branched stent graft for the reconstruction of the canine aortic arch. The unibody branched stent grafts included single branched stent grafts and double branched stent grafts. The main stent graft and branched limbs were sutured together. The branched stent grafts were folded into the introducer system, which consisted of a double channel catheter, a detachable sleeve, and an introducer sheath. The branched stent grafts were introduced and deployed into the aortic arch by the delivery system. Twenty adult mongrel dogs were used for the experiments. Ten dogs were implanted with single branched stent grafts; the other 10 were implanted with double branched stent grafts. The surviving animals were followed up for 3 months. Computed tomography angiography (CTA) was performed to observe the status of the branched stent grafts. All the unibody branched stent grafts were successfully implanted into the canine aortic arches. The technical success rate was 100%. There was no cerebral infarction, paraplegia or incision infection. CTA showed that all the branched stent grafts were patent; there was no endoleak or stent migration. The unibody branched stent graft system could be used to reconstruct the aortic arch. The animal experimental procedures demonstrated the safety and feasibility of the unibody branched stent graft system. Copyright © 2018 European Society for Vascular Surgery. Published by Elsevier B.V. All rights reserved.

Preliminary investigation of the effects of surface treatments on biological response to shape memory NiTi stents.

PubMed

Trépanier, C; Leung, T K; Tabrizian, M; Yahia, L H; Bienvenu, J G; Tanguay, J F; Piron, D L; Bilodeau, L

1999-01-01

Nickel-titanium (NiTi) offers many advantages for the fabrication of coronary stents: shape memory, superelasticity, and radiopacity. However, many authors highlighted the selective dissolution of Ni from the alloy during the corrosion process that could lead to potential toxicity. The improvement of the NiTi stent's corrosion resistance by different surface treatments (electropolishing, heat treatment, and nitric acid passivation) was reported in a previous article. In the present study a comparative biocompatibility evaluation of such stents was performed through in vitro and in vivo assays. A cell proliferation test was completed to evaluate the cytotoxicity of surface treated NiTi using human fibroblasts. Then a stent implantation was performed in rabbit paramuscular muscle to study the inflammatory response generated by the same implants. Cell proliferation tests generally indicated an in vitro biocompatibility of our samples similar to the control group. An in vivo implantation study demonstrated the gradual overall reduction with time of the fibrocellular capsule thickness surrounding the implants. After a 12-week implantation period, the fibrous capsules surrounding the different implants tended toward the same value of 0.07 mm, which suggested that all surface treatments produced a similar biological response. This low value of the fibrocellular capsule indicated that our NiTi surface treated implants were relatively inert.

Percutaneous valved stent implantation in the ascending aorta for the treatment of very high-risk aortic regurgitation: an animal study.

PubMed

Zong, Gang-Jun; Jiang, Hai-Bin; Bai, Yuan; Wu, Gang-Yong; Ye, Guang-Ming; Chen, Jing-Kai; Qin, Yong-Wen; Zhao, Xian-xian

2013-12-01

We investigated the effects of percutaneous valved stent implantation in the ascending aorta as an alternative treatment for aortic regurgitation in a canine model. A total of 16 healthy dogs weighing an average of 18.3 ± 2.1 kg were used for the establishment of animal models of chronic aortic regurgitation by percutaneous aortic valve perforation and balloon dilation. At 2 mo after successful model establishment, all experimental animals underwent valved stent implantation in the ascending aorta and then were followed up for 3 mo. Experimental models of chronic aortic regurgitation were successfully established in 10 dogs. Surviving dogs underwent successful valved stent implantation in the ascending aorta and were subsequently followed up for 3 mo. The level of instantaneous aortic regurgitation at 3-mo follow-up was significantly reduced compared with that before valved stent implantation (2.4 ± 0.9 versus 10.6 ± 2.1 mL/s, P < 0.05). The left ventricular ejection fraction was significantly increased (53.8 ± 4.2% versus 37.8 ± 3.7%, P < 0.05), and the left ventricular end-diastolic volume was also significantly reduced (30.3 ± 2.2 versus 40.1 ± 3.6 mL, P < 0.05). No paravalvular leak, stroke, atrioventricular block, or other complications occurred in dogs undergoing valved stent implantation. Percutaneous valved stent implantation in the ascending aorta is feasible, effective, and safe as an alternative treatment for very high-risk aortic regurgitation in a canine model. Copyright © 2013 Elsevier Inc. All rights reserved.

AMS INSIGHT--absorbable metal stent implantation for treatment of below-the-knee critical limb ischemia: 6-month analysis.

PubMed

Bosiers, Marc; Peeters, Patrick; D'Archambeau, Olivier; Hendriks, Jeroen; Pilger, Ernst; Düber, Christoph; Zeller, Thomas; Gussmann, Andreas; Lohle, Paul N M; Minar, Erich; Scheinert, Dierk; Hausegger, Klaus; Schulte, Karl-Ludwig; Verbist, Jürgen; Deloose, Koen; Lammer, J

2009-05-01

Endoluminal treatment of infrapopliteal artery lesions is a matter of controversy. Bioabsorbable stents are discussed as a means to combine mechanical prevention of vessel recoil with the advantages of long-term perspectives. The possibility of not having a permanent metallic implant could permit the occurrence of positive remodeling with lumen enlargement to compensate for the development of new lesions. The present study was designed to investigate the safety of absorbable metal stents (AMSs) in the infrapopliteal arteries based on 1- and 6-month clinical follow-up and efficacy based on 6-month angiographic patency. One hundred seventeen patients with 149 lesions with chronic limb ischemia (CLI) were randomized to implantation of an AMS (60 patients, 74 lesions) or stand-alone percutaneous transluminal angioplasty (PTA; 57 patients, 75 lesions). Seven PTA-group patients "crossed over" to AMS stenting. The study population consisted of patients with symptomatic CLI (Rutherford categories 4 and 5) and de novo stenotic (>50%) or occlusive atherosclerotic disease of the infrapopliteal arteries who presented with a reference diameter of between 3.0 and 3.5 mm and a lesion length of <15 mm. The primary safety endpoint was defined as absence of major amputation and/or death within 30 days after index intervention and the primary efficacy endpoint was the 6-month angiographic patency rate as confirmed by core-lab quantitative vessel analysis. The 30-day complication rate was 5.3% (3/57) and 5.0% (3/60) in patients randomized for PTA alone and PTA followed by AMS implantation, respectively. On an intention-to-treat basis, the 6-month angiographic patency rate for lesions treated with AMS (31.8%) was significantly lower (p = 0.013) than the rate for those treated with PTA (58.0%). Although the present study indicates that the AMS technology can be safely applied, it did not demonstrate efficacy in long-term patency over standard PTA in the infrapopliteal vessels.

Previous coronary stent implantation and cardiac events in patients undergoing noncardiac surgery.

PubMed

Cruden, Nicholas L M; Harding, Scott A; Flapan, Andrew D; Graham, Cat; Wild, Sarah H; Slack, Rachel; Pell, Jill P; Newby, David E

2010-06-01

Noncardiac surgery performed after coronary stent implantation is associated with an increased risk of stent thrombosis, myocardial infarction, and death. The influence of stent type and period of risk still have to be defined. We linked the Scottish Coronary Revascularisation Register with hospital admission data to undertake a Scotland-wide retrospective cohort study examining cardiac outcomes in all patients who received drug-eluting or bare-metal stents between April 2003 and March 2007 and subsequently underwent noncardiac surgery. Of 1953 patients, 570 (29%) were treated with at least 1 drug-eluting stent and 1383 (71%) with bare-metal stents only. There were no differences between drug-eluting and bare-metal stents in the primary end point of in-hospital mortality or ischemic cardiac events (14.6% versus 13.3%; P=0.3) or the secondary end points of in-hospital mortality (0.7% versus 0.6%; P=0.8) and acute myocardial infarction (1.2% versus 0.7%; P=0.3). Perioperative death and ischemic cardiac events occurred more frequently when surgery was performed within 42 days of stent implantation (42.4% versus 12.8% beyond 42 days; P<0.001), especially in patients revascularized after an acute coronary syndrome (65% versus 32%; P=0.037). There were no temporal differences in outcomes between the drug-eluting and bare-metal stent groups. Patients undergoing noncardiac surgery after recent coronary stent implantation are at increased risk of perioperative myocardial ischemia, myocardial infarction, and death, particularly after an acute coronary syndrome. For at least 2 years after percutaneous coronary intervention, cardiac outcomes after noncardiac surgery are similar for both drug-eluting and bare-metal stents.

TACE Combined with Implantation of Irradiation Stent Versus TACE Combine with Bare Stent for HCC Complicated by IVCTT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Qing-hui; Zhang, Wen; Liu, Qing-xin

PurposeThis study was designed to evaluate the safety and efficacy of transarterial chemoembolization (TACE) combined with intra-IVC implantation of an irradiation stent for the treatment of hepatocellular carcinoma (HCC) complicated by inferior vena cava tumor thrombosis (IVCTT).MethodsSixty-one consecutive patients with HCC complicated by IVCTT treated by TACE combined with IVC stenting were retrospectively analysed. IVC stenting was performed using a stent loaded with {sup 125}I seeds strands (the irradiation stent) in 33 patients (Group A) and 28 patients with a bare stent (Group B). Propensity score matching eliminated the baseline differences. Overall survival, oedema related to IVC obstruction remission ratemore » and procedure-related adverse events were compared between the two groups.ResultsThe adverse effect rate was similar for both Group A and Group B patients, and complications were adequately handled by medical treatment. TACE combined with implantation of an irradiation stent showed a significant median survival benefit over TACE combined with a bare stent, with a median survival time of 203.0 ± 28.135 days versus 93.0 ± 24.341 days (p = 0.006). The propensity score-matched (24 pairs) cohort analyses (200 ± 31.231 days vs. 66 ± 23.270 days, p = 0.019). The oedema remission rate was 97.0 % in group A patients and 96.4 % in group B, respectively. TACE-irradiation stent and object tumor response were the independent prognostic factors of favorable survival.ConclusionsTACE combined with irradiation stent implantation is a safe and effective treatment modality for patients with HCC complicated by IVCTT and may extend their survival time.« less

Impending rupture of saphenous vein graft aneurysm with floating fractured bare metal stent treated by coil embolization and covered stent implantation.

PubMed

Kodama, Atsuko; Kurita, Tairo; Kato, Osamu; Suzuki, Takahiko

2016-11-01

Aneurysmal degeneration of a saphenous vein graft (SVG) is a rare, but potentially fatal complication of coronary artery bypass graft (CABG) surgery. In this case report, a patient that had undergone prior CABG surgery and bare metal stent (BMS) implantation at the site of a stenotic SVG lesion presented at our hospital with chest pain, and an SVG aneurysm was detected at the previous BMS implantation site. In addition, the implanted BMS was fractured and floating in the SVG aneurysm. The SVG aneurysm was successfully occluded by percutaneous intervention, using a combination of distal covered stent deployment at the site of the anastomosis between the native coronary artery and the SVG and proximal coil embolization of the aneurysm.

Stenting for curved lesions using a novel curved balloon: Preliminary experimental study.

PubMed

Tomita, Hideshi; Higaki, Takashi; Kobayashi, Toshiki; Fujii, Takanari; Fujimoto, Kazuto

2015-08-01

Stenting may be a compelling approach to dilating curved lesions in congenital heart diseases. However, balloon-expandable stents, which are commonly used for congenital heart diseases, are usually deployed in a straight orientation. In this study, we evaluated the effect of stenting with a novel curved balloon considered to provide better conformability to the curved-angled lesion. In vitro experiments: A Palmaz Genesis(®) stent (Johnson & Johnson, Cordis Co, Bridgewater, NJ, USA) mounted on the Goku(®) curve (Tokai Medical Co. Nagoya, Japan) was dilated in vitro to observe directly the behavior of the stent and balloon assembly during expansion. Animal experiment: A short Express(®) Vascular SD (Boston Scientific Co, Marlborough, MA, USA) stent and a long Express(®) Vascular LD stent (Boston Scientific) mounted on the curved balloon were deployed in the curved vessel of a pig to observe the effect of stenting in vivo. In vitro experiments: Although the stent was dilated in a curved fashion, stent and balloon assembly also rotated conjointly during expansion of its curved portion. In the primary stenting of the short stent, the stent was dilated with rotation of the curved portion. The excised stent conformed to the curved vessel. As the long stent could not be negotiated across the mid-portion with the balloon in expansion when it started curving, the mid-portion of the stent failed to expand fully. Furthermore, the balloon, which became entangled with the stent strut, could not be retrieved even after complete deflation. This novel curved balloon catheter might be used for implantation of the short stent in a curved lesion; however, it should not be used for primary stenting of the long stent. Post-dilation to conform the stent to the angled vessel would be safer than primary stenting irrespective of stent length. Copyright © 2014 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.

Quantitative multi-modality imaging analysis of a bioabsorbable poly-L-lactic acid stent design in the acute phase: a comparison between 2- and 3D-QCA, QCU and QMSCT-CA.

PubMed

Bruining, Nico; Tanimoto, Shuzou; Otsuka, Masato; Weustink, Annick; Ligthart, Jurgen; de Winter, Sebastiaan; van Mieghem, Carlos; Nieman, Koen; de Feyter, Pim J; van Domburg, Ron T; Serruys, Patrick W

2008-08-01

To investigate if three-dimensional (3D) based quantitative techniques are comparable to each other and to explore possible differences with respect to the reference method of 2D-QCA in the acute phase and to study whether non-invasive MSCT could potentially be applied to quantify luminal dimensions of a stented coronary segment with a novel bioabsorable drug-eluting stent made of poly-l-lactic-acid (PLLA). Quantitative imaging data derived from 16 patients enrolled at our institution in a first-in-man trial (ABSORB) receiving a biodegradable stent and who were imaged with standard coronary angiography and intravascular ultrasound were compared. Shortly, after stenting the patients also underwent a MSCT procedure. Standard 2D-QCA showed significant smaller stent lengths (p < 0.01). Although, the absolute measured stent diameters and areas by 2D-QCA tend to be smaller, the differences failed to be statistically different when compared to the 3D based quantitative modalities. Measurements made by non-invasive QMSCT-CA of implanted PLLA stents appeared to be comparable to the other 3D modalities without significant differences. Three-dimensional based quantitative analyses showed similar results quantifying luminal dimensions as compared to 2D-QCA during an evaluation of a new bioabsorbable coronary stent design in the acute phase. Furthermore, in biodegradable stents made of PLLA, non-invasive QMSCT-CA can be used to quantify luminal dimensions.

Efficacy of a Dexamethasone-Eluting Nitinol Stent on the Inhibition of Pseudointimal Hyperplasia in a Transjugular Intrahepatic Portosystemic Shunt: An Experimental Study in a Swine Model

PubMed Central

Seo, Tae-Seok; Park, Young-Koo; Song, Ho-Young; Park, Sang Joon; Yuk, Sun-Hong

2005-01-01

Objective We wanted to evaluate the feasibility and efficacy of using a dexamethasone (DM)-eluting nitinol stent to inhibit the pseudointimal hyperplasia following stent placement in the transjugular intrahepatic portosystemic shunt tract (TIPS) of a swine. Materials and Methods Fifteen stents were constructed using 0.15 mm-thick nitinol wire; they were 60 mm in length and 10 mm in diameter. The metallic stents were then classified into three types; type 1 and 2 was coated with the mixture of 12% and 20%, respectively, of DM solution and polyurethane (PU), while type 3 was a bare stent that was used for control study. In fifteen swine, each type of stent was implanted in the TIPS tract of 5 swine, and each animal was sacrificed 2 weeks after TIPS creation. The proliferation of the pseudointima was evaluated both on follow-up portogram and pathologic examination. Results One TIPS case, using the type 1 stent, and two TIPS cases, using the type 2 stent, maintained their luminal patency while the others were all occluded. On the histopathologic analysis, the mean of the maximum pseudointimal hyperplasia was expressed as the percentage of the stent radius that was patent, and these values were 51.2%, 50% and 76% for the type 1, 2, and 3 stents, respectively. Conclusion The DM-eluting stent showed a tendency to reduce the development of pseudointimal hyperplasia in the TIPS tract of a swine model with induced-portal hypertension. PMID:16374082

Cardiac Procedures and Surgeries

MedlinePlus

... or cutoff. Often combined with implantation of a stent (see below) to help prop the artery open ... or cutoff. Often combined with implantation of a stent (see below) to help prop the artery open ...

Targeting In-Stent-Stenosis with RGD- and CXCL1-Coated Mini-Stents in Mice.

PubMed

Simsekyilmaz, Sakine; Liehn, Elisa A; Weinandy, Stefan; Schreiber, Fabian; Megens, Remco T A; Theelen, Wendy; Smeets, Ralf; Jockenhövel, Stefan; Gries, Thomas; Möller, Martin; Klee, Doris; Weber, Christian; Zernecke, Alma

2016-01-01

Atherosclerotic lesions that critically narrow the artery can necessitate an angioplasty and stent implantation. Long-term therapeutic effects, however, are limited by excessive arterial remodeling. We here employed a miniaturized nitinol-stent coated with star-shaped polyethylenglycole (star-PEG), and evaluated its bio-functionalization with RGD and CXCL1 for improving in-stent stenosis after implantation into carotid arteries of mice. Nitinol foils or stents (bare metal) were coated with star-PEG, and bio-functionalized with RGD, or RGD/CXCL1. Cell adhesion to star-PEG-coated nitinol foils was unaltered or reduced, whereas bio-functionalization with RGD but foremost RGD/CXCL1 increased adhesion of early angiogenic outgrowth cells (EOCs) and endothelial cells but not smooth muscle cells when compared with bare metal foils. Stimulation of cells with RGD/CXCL1 furthermore increased the proliferation of EOCs. In vivo, bio-functionalization with RGD/CXCL1 significantly reduced neointima formation and thrombus formation, and increased re-endothelialization in apoE-/- carotid arteries compared with bare-metal nitinol stents, star-PEG-coated stents, and stents bio-functionalized with RGD only. Bio-functionalization of star-PEG-coated nitinol-stents with RGD/CXCL1 reduced in-stent neointima formation. By supporting the adhesion and proliferation of endothelial progenitor cells, RGD/CXCL1 coating of stents may help to accelerate endothelial repair after stent implantation, and thus may harbor the potential to limit the complication of in-stent restenosis in clinical approaches.

Targeting In-Stent-Stenosis with RGD- and CXCL1-Coated Mini-Stents in Mice

PubMed Central

Weinandy, Stefan; Schreiber, Fabian; Megens, Remco T. A.; Theelen, Wendy; Smeets, Ralf; Jockenhövel, Stefan; Gries, Thomas; Möller, Martin; Klee, Doris; Weber, Christian; Zernecke, Alma

2016-01-01

Atherosclerotic lesions that critically narrow the artery can necessitate an angioplasty and stent implantation. Long-term therapeutic effects, however, are limited by excessive arterial remodeling. We here employed a miniaturized nitinol-stent coated with star-shaped polyethylenglycole (star-PEG), and evaluated its bio-functionalization with RGD and CXCL1 for improving in-stent stenosis after implantation into carotid arteries of mice. Nitinol foils or stents (bare metal) were coated with star-PEG, and bio-functionalized with RGD, or RGD/CXCL1. Cell adhesion to star-PEG-coated nitinol foils was unaltered or reduced, whereas bio-functionalization with RGD but foremost RGD/CXCL1 increased adhesion of early angiogenic outgrowth cells (EOCs) and endothelial cells but not smooth muscle cells when compared with bare metal foils. Stimulation of cells with RGD/CXCL1 furthermore increased the proliferation of EOCs. In vivo, bio-functionalization with RGD/CXCL1 significantly reduced neointima formation and thrombus formation, and increased re-endothelialization in apoE-/- carotid arteries compared with bare-metal nitinol stents, star-PEG-coated stents, and stents bio-functionalized with RGD only. Bio-functionalization of star-PEG-coated nitinol-stents with RGD/CXCL1 reduced in-stent neointima formation. By supporting the adhesion and proliferation of endothelial progenitor cells, RGD/CXCL1 coating of stents may help to accelerate endothelial repair after stent implantation, and thus may harbor the potential to limit the complication of in-stent restenosis in clinical approaches. PMID:27192172

A prospective, multicenter, post marketing surveillance study to evaluate the safety and effectiveness of the Superia-Sirolimus Eluting Coronary Stent System (SSECSS) implanted during routine clinical practice in India.

PubMed

Chandra, Praveen; Kumar, Tarun

2014-01-01

A prospective, multicenter, post marketing surveillance study to evaluate the safety and effectiveness of the Superia-Sirolimus Eluting Coronary Stent System (SSECSS) implanted during routine clinical practice in India. 1. To study the MACE and in stent and In-segment Loss at Six Months (in a pre selected group of 50 patients). 1. Clinical and procedural success. This is a prospective, open label, single-arm, multicenter (16 sites), post marketing observational study enrolling patients implanted with Superia-Sirolimus Eluting Coronary Stent (SSECS) in routine clinical practice in India. A total of 200 Patients of coronary Artery Disease (CAD) implanted with Superia-Sirolimus Eluting Coronary Stent (SSECS) were enrolled. Clinical assessments were done at 30 days, 180 days and at 1, 2 years either telephonically or office visit. A cohort of 50 pre-selected patients were followed up for angiographic evaluation at 180 days. MACE at 12 month of follow up was 1.71%.Late lumen loss, in segment was 0.14 and in stent was 0.10 mm at 6 month of follow-up. TLR was required only in 2 patients. Superia stent is as safe as other biodegradable polymer stent in the market and time has come for biodegradable polymer stent with thin struts. Copyright © 2014 Cardiological Society of India. Published by Elsevier B.V. All rights reserved.

Impact of nitinol stent surface processing on in-vivo nickel release and biological response.

PubMed

Nagaraja, Srinidhi; Sullivan, Stacey J L; Stafford, Philip R; Lucas, Anne D; Malkin, Elon

2018-05-01

Although nitinol is widely used in percutaneous cardiovascular interventions, a causal relationship between nickel released from implanted cardiovascular devices and adverse systemic or local biological responses has not been established. The objective of this study was to investigate the relationship between nitinol surface processing, in-vivo nickel release, and biocompatibility. Nitinol stents manufactured using select surface treatments were implanted into the iliac arteries of minipigs for 6 months. Clinical chemistry profile, complete blood count, serum and urine nickel analyses were performed periodically during the implantation period. After explant, stented arteries were either digested and analyzed for local nickel concentration or fixed and sectioned for histopathological analysis of stenosis and inflammation within the artery. The results indicated that markers for liver and kidney function were not different than baseline values throughout 180 days of implantation regardless of surface finish. In addition, white blood cell, red blood cell, and platelet counts were similar to baseline values for all surface finishes. Systemic nickel concentrations in serum and urine were not significantly different between processing groups and comparable to baseline values during 180 days of implantation. However, stents with non-optimized surface finishing had significantly greater nickel levels in the surrounding artery compared to polished stents. These stents had increased stenosis with potential for local inflammation compared to polished stents. These findings demonstrate that proper polishing of nitinol surfaces can reduce in-vivo nickel release locally, which may aid in minimizing adverse inflammatory reactions and restenosis. Nitinol is a commonly used material in cardiovascular medical devices. However, relationships between nitinol surface finishing, in-vivo metal ion release, and adverse biological responses have yet to be established. We addressed this knowledge gap by implanting single and overlapped nitinol stents with different surface finishes to assess systemic impact on minipigs (i.e. serum and urine nickel levels, liver and kidney function, immune and blood count) over the 6 month implantation period. In addition, nickel levels and histopathology in stented arteries were analyzed on explant to determine relationships between surface processing and local adverse tissue reactions. The findings presented here highlight the importance of surface processing on in-vivo nickel release and subsequent impact on local biological response for nitinol implants. Published by Elsevier Ltd.

[Application of (125)I seeds combined with biliary stent implantation in the treatment of malignant obstructive jaundice].

PubMed

Wang, T; Liu, S; Zheng, Y B; Song, X P; Jiang, W J; Sun, B L; Wang, L G

2016-03-23

To study the feasibility and therapeutic effect of the application of (125)I seeds combined with biliary stent implantation on the treatment of malignant obstructive jaundice. Fifty patients with malignant obstructive jaundice treated from September 2010 to February 2013 in Yantai Yuhuangding Hospital were included in this study. Among them, 24 patients received biliary stent implantation combined with (125)I seeds intraluminal brachytherapy as experimental group, and 26 were treated by biliary stent implantation as control group.The total bilirubin, direct bilirubin and tumor markers (CA-199, CA-242, CEA) before and after surgery, the biliary stent patency status was assessed, and the survival time was evaluated. The 24 patients in experimental group were implanted with 30 (125)I seeds successfully in a total of 450 seeds. Jaundice was improved greatly in both groups. The CA-199 and CA-242 after treatment in the experimental group were significantly decreased than that before treatment (P=0.003 and P=0.004). CEA was also decreased, but showed no statistical significance (P>0.05). There were no significant improvement comparing the CA-199, CA-242 and CEA before and 2 months after surgery in the control group (P>0.05). The rate of biliary stent patency was 83.3% (20/24) in the experimental group and 57.7% (15/26) in the control group (P=0.048). The mean biliary stent patency time in the experimental group was 9.84 months (range 1-15.5 months). The mean biliary stent patency time in the control group was 5.57 months (range 0.8-9 months). There was a significant difference between the two groups (P=0.018). The median survival time was 10.2 months in the experimental group and 5.4 months in the control group (P<0.05). (125)I seeds combined with biliary stent implantation can inhibit the proliferation of vascular endothelial cells and the growth of tumor effectively, and can prolong the biliary stent patency time and the survival time obviously for patients with malignant obstructive jaundice, therefore, is a safe and effective treatment in this malignancy.

Stents Eluting 6-Mercaptopurine Reduce Neointima Formation and Inflammation while Enhancing Strut Coverage in Rabbits

PubMed Central

Ruiter, Matthijs S.; van Tiel, Claudia M.; Doornbos, Albert; Marinković, Goran; Strang, Aart C.; Attevelt, Nico J. M.; de Waard, Vivian; de Winter, Robbert J.; Steendam, Rob; de Vries, Carlie J. M.

2015-01-01

Background The introduction of drug-eluting stents (DES) has dramatically reduced restenosis rates compared with bare metal stents, but in-stent thrombosis remains a safety concern, necessitating prolonged dual anti-platelet therapy. The drug 6-Mercaptopurine (6-MP) has been shown to have beneficial effects in a cell-specific fashion on smooth muscle cells (SMC), endothelial cells and macrophages. We generated and analyzed a novel bioresorbable polymer coated DES, releasing 6-MP into the vessel wall, to reduce restenosis by inhibiting SMC proliferation and decreasing inflammation, without negatively affecting endothelialization of the stent surface. Methods Stents spray-coated with a bioresorbable polymer containing 0, 30 or 300 μg 6-MP were implanted in the iliac arteries of 17 male New Zealand White rabbits. Animals were euthanized for stent harvest 1 week after implantation for evaluation of cellular stent coverage and after 4 weeks for morphometric analyses of the lesions. Results Four weeks after implantation, the high dose of 6-MP attenuated restenosis with 16% compared to controls. Reduced neointima formation could at least partly be explained by an almost 2-fold induction of the cell cycle inhibiting kinase p27Kip1. Additionally, inflammation score, the quantification of RAM11-positive cells in the vessel wall, was significantly reduced in the high dose group with 23% compared to the control group. Evaluation with scanning electron microscopy showed 6-MP did not inhibit strut coverage 1 week after implantation. Conclusion We demonstrate that novel stents coated with a bioresorbable polymer coating eluting 6-MP inhibit restenosis and attenuate inflammation, while stimulating endothelial coverage. The 6-MP-eluting stents demonstrate that inhibition of restenosis without leaving uncovered metal is feasible, bringing stents without risk of late thrombosis one step closer to the patient. PMID:26389595

Genous™ endothelial progenitor cell capturing stent vs. the Taxus Liberté stent in patients with de novo coronary lesions with a high-risk of coronary restenosis: a randomized, single-centre, pilot study

PubMed Central

Beijk, Marcel A.M.; Klomp, Margo; Verouden, Niels J.W.; van Geloven, Nan; Koch, Karel T.; Henriques, José P.S.; Baan, Jan; Vis, Marije M.; Scheunhage, Esther; Piek, Jan J.; Tijssen, Jan G.P.; de Winter, Robbert J.

2010-01-01

Aims The purpose of this study was to evaluate the GenousTM endothelial progenitor cell capturing stent vs. the Taxus Liberté paclitaxel-eluting stent in patients with de novo coronary lesions with a high-risk of coronary restenosis. Methods and results We randomly assigned 193 patients with lesions carrying a high risk of restenosis to have the Genous stent or the Taxus stent implanted. Lesions were considered high risk of restenosis if one of the following applied: chronic total occlusion, lesion length >23 mm, vessel diameter <2.8 mm, or any lesion in a diabetic patient. At 1-year, the rate of the primary end point, target vessel failure (TVF), was 17.3% in the Genous stent group when compared with 10.5% in the Taxus stent group [risk difference (RD) 6.8%, 95% CI −3.1 to 16.7%], a difference predominantly due to a higher incidence of repeat revascularization in patients treated with the Genous stent. In contrast, no stent thrombosis was observed in the Genous stent group compared to 4 stent thromboses in the Taxus stent group (RD −4.2%; 95% CI −10.3 to 0.3%). Repeat angiography between 6 and 12 months in a subgroup of patients showed a significantly higher late loss in the Genous stent compared with the Taxus stent (1.14 ± 0.64 and 0.55 ± 0.61 mm). Conclusion In patients with lesions carrying a high risk of restenosis, the Genous stent resulted in a non-significant higher rate of TVF compared with the Taxus stent mainly due to more repeat revascularizations in the Genous stent group. There were four stent thromboses with Taxus stent, none with the Genous stent. PMID:19933225

Evaluation of Polyurethane Nasolacrimal Duct Stents: In Vivo Studies in New Zealand Rabbits

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wilhelm, K.E., E-mail: wilhelm@uni-bonn.de; Grabolle, B.; Urbach, H.

2006-10-15

The purpose of this study was to evaluate the radiographic and biological effects of different polyurethane nasolacrimal duct stents in an animal model. Fifteen polyurethane nasolacrimal duct stents (n = 5 mushroom-type stents, n = 5 newly designed S-shaped TearLeader stents without hydrophilic coating, and n = 5 S-shaped TearLeader stents with hydrophilic coating) were implanted in the nasolacrimal ducts of eight unaffected New Zealand rabbits. One nasolacrimal system served as control. Clinical and radiographic follow-up was performed at 1-, 2-, and 4-week intervals, then after a 3-month interval, after which the animals were euthanized. All stents were implanted withoutmore » major periprocedural complications. The stents proved to be patent by the end of the procedure. During follow-up, all mushroom-type stents were occluded at 4 weeks. None of these stents opened to forced irrigation. Clinically, all rabbits demonstrated severe dacryocystitis. Three out of five TearLeader stents without hydrophilic coating were blocked at 4 weeks; one out of five was open to irrigation. Best results were observed in the stent group with hydrophilic coating. Follow-up dacryocystography demonstrated patent stents in nasolacrimal ducts of all animals after 4 weeks. In only one of five cases, the coated stent became partially occluded after 2 months. These animals were free of clinical symptoms. After 3 months, at least three out of five stents still opened to forced irrigation and only one stent was completely blocked. Dislocation of the stents was not observed. Refinement of the stent surface and stent design improves the results of nasolacrimal duct stenting in this animal model. Implantation of hydrophilic-coated S-shaped stents is highly superior to conventional mushroom-type stents and noncoated stent types. Hydrophilic coating seems to prevent foreign-body reactions, resulting in maximized stent patency.« less

Hemodynamic alterations after stent implantation in 15 cases of intracranial aneurysm.

PubMed

Wang, Chao; Tian, Zhongbin; Liu, Jian; Jing, Linkai; Paliwal, Nikhil; Wang, Shengzhang; Zhang, Ying; Xiang, Jianping; Siddiqui, Adnan H; Meng, Hui; Yang, Xinjian

2016-04-01

Stent-assisted coiling technology has been widely used in the treatment of intracranial aneurysms. In the current study, we investigated the intra-aneurysmal hemodynamic alterations after stent implantation and their association with the aneurysm location. We first retrospectively studied 15 aneurysm cases [8 internal carotid artery-ophthalmic artery (ICA-OphA) aneurysms and 7 posterior communicating artery (PcoA) aneurysms] treated with Enterprise stents and coils. Then, based on the patient-specific geometries before and after stenting, we built virtual stenting computational fluid dynamics (CFD) simulation models. Before and after the stent deployment, the average wall shear stress (WSS) on the aneurysmal sac at systolic peak changed from 7.04 Pa (4.14 Pa, 15.77 Pa) to 6.04 Pa (3.86 Pa, 11.13 Pa), P = 0.001; the spatially averaged flow velocity in the perpendicular plane of the aneurysm dropped from 0.5 m/s (0.28 m/s, 0.7 m/s) to 0.33 m/s (0.25 m/s, 0.49 m/s), P = 0.001, respectively. Post stent implantation, the WSS in ICA-OphA aneurysms and PcoA aneurysms decreased by 14.4 % (P = 0.012) and 16.6 % (P = 0.018), respectively, and the flow velocity also reduced by 10.3 % (P = 0.029) and 10.5 % (P = 0.013), respectively. Changes in the WSS, flow velocity, and pressure were not significantly different between ICA-OphA and PcoA aneurysms (P > 0.05). Stent implantation did not significantly change the peak systolic pressure in either aneurysm type. After the stent implantation, both the intra-aneurysmal flow velocity and WSS decreased independently of aneurysm type (ICA-OphA and PcoA). Little change was observed in peak systolic pressure.

The Safety and efficacy of a new self-expandable intratracheal nitinol stent for the tracheal collapse in dogs

PubMed Central

Kim, Joon-young; Han, Hyun-jung; Yun, Hun-young; Lee, Bora; Jang, Ha-young; Eom, Ki-dong; Park, Hee-myung

2008-01-01

To evaluate the potential utility of a self-expandable intratracheal nitinol stent with flared ends for the treatment of tracheal collapse in dogs, endotracheal stenting therapy was performed under fluoroscopic guidance in four dogs with severe tracheal collapse. During the 4 to 7 month follow-up, after stent implantation, clinical signs, including dyspnea and respiratory distress, dramatically improved in all dogs. The radiographs showed that the implanted stents improved the tracheal collapse, and there were no side effects such as collapse, shortening or migration of the stents. In conclusion, the self-expandable intratracheal nitinol stents provided adequate stability to the trachea and were effective for attenuating the clinical signs associated with severe tracheal collapse. PMID:18296893

Prospective, randomized study of one, two, or three trabecular bypass stents in open-angle glaucoma subjects on topical hypotensive medication

PubMed Central

Katz, L Jay; Erb, Carl; Carceller, Guillamet Amadeu; Fea, Antonio M; Voskanyan, Lilit; Wells, Jeffrey M; Giamporcaro, Jane Ellen

2015-01-01

Purpose To assess the safety and efficacy of one, two, or three trabecular microbypass stents in eyes with primary open-angle glaucoma (OAG) not controlled on ocular hypotensive medication. A total of 119 subjects were followed for 18 months postoperatively. Materials and methods Subjects with medicated intraocular pressure (IOP) 18–30 mmHg and postmedication-washout baseline IOP 22–38 mmHg were randomized to implantation of one, two, or three stents. Ocular hypotensive medication was to be used if postoperative IOP exceeded 18 mmHg. Results A total of 38 subjects were implanted with one stent, 41 subjects with two stents, and 40 subjects with three stents. Both month 12 IOP reduction ≥20% without ocular hypotensive medication vs baseline unmedicated IOP and month 12 unmedicated IOP ≤18 mmHg were achieved by 89.2%, 90.2%, and 92.1% of one-, two-, and three-stent eyes, respectively. Furthermore, 64.9%, 85.4%, and 92.1% of the three respective groups achieved unmedicated IOP ≤15 mmHg. Over the 18-month follow-up period, medication was required in seven one-stent subjects, four two-stent subjects, and three three-stent subjects. At 18 months, mean unmedicated IOP was 15.9±0.9 mmHg in one-stent subjects, 14.1±1.0 mmHg in two-stent subjects, and 12.2±1.1 mmHg in three-stent subjects. Month 18 IOP reduction was significantly greater (P<0.001) with implantation of each additional stent, with mean differences in reduction of 1.84 mmHg (95% confidence interval 0.96–2.73) for three-stent vs two-stent groups and 1.73 mmHg (95% confidence interval 0.83–2.64) for two-stent vs one-stent groups. Adverse events through 18 months were limited to cataract progression with best-corrected visual acuity loss and subsequent cataract surgery. Conclusion In this series, implantation of each additional stent resulted in significantly greater IOP reduction with reduced medication use. Titratability of stents as a sole procedure was shown to be effective and safe, with sustained effect through 18 months postoperatively in OAG not controlled with medication. PMID:26715834

Optical Coherence Tomography and Stent Boost Imaging Guided Bioresorbable Vascular Scaffold Overlapping for Coronary Chronic Total Occlusion Lesion

PubMed Central

Li, Hu; Choi, Cheol Ung; Oh, Dong Joo

2017-01-01

We report herein the optical coherence tomography (OCT) and stent boost imaging guided bioresorbable vascular scaffold (BVS) implantation for right coronary artery (RCA) chronic total occlusion (CTO) lesion. The gold standard for evaluating BVS expansion after percutaneous coronary intervention is OCT. However, stent boost imaging is a new technique that improves fluoroscopy-based assessments of stent overlapping, and the present case shows clinical usefulness of OCT and stent boost imaging guided ‘overlapping’ BVS implantation via antegrade approach for a typical RCA CTO lesion. PMID:28792157

Collagen Matrix Remodeling in Stented Pulmonary Arteries after Transapical Heart Valve Replacement.

PubMed

Ghazanfari, Samaneh; Driessen-Mol, Anita; Hoerstrup, Simon P; Baaijens, Frank P T; Bouten, Carlijn V C

2016-01-01

The use of valved stents for minimally invasive replacement of semilunar heart valves is expected to change the extracellular matrix and mechanical function of the native artery and may thus impair long-term functionality of the implant. Here we investigate the impact of the stent on matrix remodeling of the pulmonary artery in a sheep model, focusing on matrix composition and collagen (re)orientation of the host tissue. Ovine native pulmonary arteries were harvested 8 (n = 2), 16 (n = 4) and 24 (n = 2) weeks after transapical implantation of self-expandable stented heart valves. Second harmonic generation (SHG) microscopy was used to assess the collagen (re)orientation of fresh tissue samples. The collagen and elastin content was quantified using biochemical assays. SHG microscopy revealed regional differences in collagen organization in all explants. In the adventitial layer of the arterial wall far distal to the stent (considered as the control tissue), we observed wavy collagen fibers oriented in the circumferential direction. These circumferential fibers were more straightened in the adventitial layer located behind the stent. On the luminal side of the wall behind the stent, collagen fibers were aligned along the stent struts and randomly oriented between the struts. Immediately distal to the stent, however, fibers on both the luminal and the adventitial side of the wall were oriented in the axial direction, demonstrating the stent impact on the collagen structure of surrounding arterial tissues. Collagen orientation patterns did not change with implantation time, and biochemical analyses showed no changes in the trend of collagen and elastin content with implantation time or location of the vascular wall. We hypothesize that the collagen fibers on the adventitial side of the arterial wall and behind the stent straighten in response to the arterial stretch caused by oversizing of the stent. However, the collagen organization on the luminal side suggests that stent-induced remodeling is dominated by contact guidance. © 2016 S. Karger AG, Basel.

Radiopaque biodegradable stent for duct-to-duct biliary reconstruction in pigs.

PubMed

Tanimoto, Yoshisato; Tashiro, Hirotaka; Mikuriya, Yoshihiro; Kuroda, Shintaro; Hashimoto, Masakazu; Kobayashi, Tsuyoshi; Taniura, Tokunori; Ohdan, Hideki

2016-06-01

Biliary stricture is a common cause of morbidity after liver transplantation. We previously developed a duct-to-duct biliary anastomosis technique using a biodegradable stent tube and confirmed the feasibility and safety of biliary stent use. However, the duration and mechanism of biliary stent absorption in the common bile duct remain unclear. Radiopaque biodegradable biliary stents were created using a copolymer of L-lactide and ε-caprolactone (70: 30) and coated with barium sulfate. Stents were surgically implanted in the common bile duct of 11 pigs. Liver function tests and computed tomography (CT) scans were performed postoperatively, and autopsies were conducted 6 months after biliary stent implantation. After the surgery, all 11 pigs had normal liver function and survived without any significant complications such as biliary leakage. A CT scan at 2 months post-procedure showed that the biliary stents were located in the hilum of the liver. The stents were not visible by CT scan at the 6-month follow-up examination. The surgical implantation of radiopaque biodegradable biliary stents in biliary surgery represents a new option for duct-to-duct biliary reconstruction. This technique appears to be feasible and safe and is not associated with any significant biliary complications. The advantage of coated biliary stent use is that it may be visualized using abdominal radiography such as CT.

Biocorrosion of magnesium alloys: a new principle in cardiovascular implant technology?

PubMed Central

Heublein, B; Rohde, R; Kaese, V; Niemeyer, M; Hartung, W; Haverich, A

2003-01-01

Objectives: To develop and test a new concept of the degradation kinetics of newly developed coronary stents consisting of magnesium alloys. Methods: Design of a coronary stent prototype consisting of the non-commercial magnesium based alloy AE21 (containing 2% aluminium and 1% rare earths) with an expected 50% loss of mass within six months. Eleven domestic pigs underwent coronary implantation of 20 stents (overstretch injury). Results: No stent caused major problems during implantation or showed signs of initial breakage in the histological evaluation. There were no thromboembolic events. Quantitative angiography at follow up showed a significant (p < 0.01) 40% loss of perfused lumen diameter between days 10 and 35, corresponding to neointima formation seen on histological analysis, and a 25% re-enlargement (p < 0.05) between days 35 and 56 caused by vascular remodelling (based on intravascular ultrasound) resulting from the loss of mechanical integrity of the stent. Inflammation (p < 0.001) and neointimal plaque area (p < 0.05) depended significantly on injury score. Planimetric degradation correlated with time (r = 0.67, p < 0.01). Conclusion: Vascular implants consisting of magnesium alloy degradable by biocorrosion seem to be a realistic alternative to permanent implants. PMID:12748224

Biocorrosion of magnesium alloys: a new principle in cardiovascular implant technology?

PubMed

Heublein, B; Rohde, R; Kaese, V; Niemeyer, M; Hartung, W; Haverich, A

2003-06-01

To develop and test a new concept of the degradation kinetics of newly developed coronary stents consisting of magnesium alloys. Design of a coronary stent prototype consisting of the non-commercial magnesium based alloy AE21 (containing 2% aluminium and 1% rare earths) with an expected 50% loss of mass within six months. Eleven domestic pigs underwent coronary implantation of 20 stents (overstretch injury). No stent caused major problems during implantation or showed signs of initial breakage in the histological evaluation. There were no thromboembolic events. Quantitative angiography at follow up showed a significant (p < 0.01) 40% loss of perfused lumen diameter between days 10 and 35, corresponding to neointima formation seen on histological analysis, and a 25% re-enlargement (p < 0.05) between days 35 and 56 caused by vascular remodelling (based on intravascular ultrasound) resulting from the loss of mechanical integrity of the stent. Inflammation (p < 0.001) and neointimal plaque area (p < 0.05) depended significantly on injury score. Planimetric degradation correlated with time (r = 0.67, p < 0.01). Vascular implants consisting of magnesium alloy degradable by biocorrosion seem to be a realistic alternative to permanent implants.

A clinical evaluation of the ProNOVA XR polymer-free sirolimus eluting coronary stent system in the treatment of patients with de novo coronary artery lesions (EURONOVA XR I study)☆

PubMed Central

Legutko, Jacek; Zasada, Wojciech; Kałuża, Grzegorz L.; Heba, Grzegorz; Rzeszutko, Lukasz; Jakala, Jacek; Dragan, Jacek; Klecha, Artur; Giszterowicz, Dawid; Dobrowolski, Wojciech; Partyka, Łukasz; Jayaraman, Swaminathan; Dudek, Dariusz

2013-01-01

Aims Evaluation of safety and efficacy of ProNOVA XR, a new generation of polymer-free sirolimus eluting stents (SES), utilizing a pharmaceutical excipient for timed release of sirolimus from the XR platform. Methods and results Safety and efficacy of ProNOVA XR coronary stent system was examined in EURONOVA prospective, single arm, multi-center registry of 50 patients with de novo native coronary lesions up to 28 mm in length in arteries between 2.25 and 4 mm. At 6-month, in-stent late lumen loss by QCA was 0.45 ± 0.41 mm and in-stent neointimal volume obstruction in the IVUS sub-study was 14 ± 11%. One-year clinical follow-up revealed a favorable safety profile, with 2% of in-hospital MACE and 6.4% of MACE from hospital discharge up to 12 months (including 1 cardiac death >30 days after stent implantation and 2 TLRs). According to the ARC definition, there was no definite or probable stent thrombosis and 1 possible stent thrombosis (2%) up to 12 months of clinical follow-up. Conclusions In this preliminary evaluation, ProNOVA XR polymer-free sirolimus eluting stent system appeared safe with an early promise of adequate effectiveness in the treatment of de novo coronary lesions in up to 12 months of clinical, angiographic and IVUS follow-up. PMID:23992999

Collagen-conjugated tracheal prosthesis tested in dogs without omental wrapping and silicone stenting.

PubMed

Liu, Yu; Lu, Tao; Zhang, Yongxing; Qiao, Yulei; Xi, Junjie; Wang, Qun

2016-11-01

Artificial tracheas fabricated from collagen-conjugated mesh appear to overcome fatal postoperative complications, namely anastomotic dehiscence and prosthesis dislocation. Such prostheses are incorporated by host tissue, provided they are wrapped in omentum (necessitating an additional abdominal procedure) and a silicone tube is used as a stent (to be extracted several weeks postoperatively). To mitigate related host impact (i.e. injury, pain and distress), we investigated the feasibility of implanting this type of tracheal prosthesis (∼5 cm in length) alone, without omental wrapping and use of a silicone stent. Porous-type tracheal prostheses that were reinforced with a continuous polypropylene spiral and sealed by collagen sponge from porcine skin replaced segments of cervical trachea (∼5 cm long) in 10 dogs through the method of telescopic anastomosis. Omental wrapping and silicone stent placement were omitted. Postoperatively, bronchoscopic examination was performed periodically. When dogs died or were sacrificed, tracheal prostheses were harvested for haematoxylin and eosin staining and electron microscopic scanning of luminal surface conditions. With the exception of one death from an anaesthesia-related incident during fibre-optic bronchoscopy (postsurgical week 1), nine dogs survived uneventfully (until sacrifice), without prosthesis dislocation or anastomotic dehiscence. The longest observation period was 2 years and 8 months. Bronchoscopic examination revealed that no stenosis or local infection was evident in the prostheses of five dogs. Moderate (n = 2) and slight (n = 2) stenoses were observed in the other four animals. All four animals survived for a long time, without dyspnoea or stridor. Histological examination showed that partial inner surface of the artificial trachea was covered with the pseudostratified ciliated epithelium. Regeneration of ciliated epithelium was also confirmed by scanning electron microscopy. This pilot study revealed that implantation of a collagen-conjugated tracheal prosthesis (∼5 cm in length) is feasible without the need for omental wrapping and silicone stenting as ancillary measures. This approach considerably simplified the surgical procedures to minimize host intrusion, which indicated a possible clinical application. © The Author 2016. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

The Effect of Cilostazol on the Angiographic Outcome of Drug-Eluting Coronary Stents Angiographic Analysis of the CILON-T (Influence of CILostazol-Based Triple Antiplatelet Therapy ON Ischemi Complication after Drug-Eluting StenT Implantation) Trial.

PubMed

Suh, Jung-Won; Lee, Seung-Pyo; Park, KyungWoo; Kang, Hyun-Jae; Koo, Bon-Kwon; Cho, Young-Seok; Youn, Tae-Jin; Chae, In-Ho; Choi, Dong-Ju; Rha, Seung-Woon; Bae, Jang-Ho; Kwon, Taek-Geun; Bae, Jang-Whan; Cho, Myeong-Chan; Kim, Hyo-Soo

2017-12-12

It is not clear if anti-restonotic effect of cilostazol is consistent for different types of drug-eluting stents (DES).The purpose of this study was to compare the anti-proliferative effect of cilostazol between DAT and TAT with consideration of confounding influences of DES type.Nine hundred and fifteen patients were randomized to either dual antiplatelet therapy (DAT; aspirin and clopidogrel) or triple antiplatelet therapy (TAT; aspirin, clopidogrel, and cilostazol) in the previous CILON-T trial. After excluding 70 patients who received both or neither stents, we analyzed 845 patients who received exclusively PES or ZES, and compared in-stent late loss at 6 months between both antiplatelet regimens (DAT versus TAT).Baseline angiographic and clinical characteristics were similar between the DAT (656 lesions in 425 patients) and the TAT group (600 lesions in 420 patients). The 6-month follow-up angiography was completed in 745 patients (88.2%). Quantitative coronary angiography showed that TAT significantly reduced in-stent late loss (DAT 0.62 ± 0.62 mm versus TAT 0.54 ± 0.49 mm, P = 0.015). Stent type, diabetes or lesion length did not interact with difference of late loss. However, reduction of late loss by cilostazol did not lead to a significant reduction in the rate of target lesion revascularization (TLR) (DAT 7.8% versus TAT 6.9%, P = 0.69) due to a nonlinear relationship found between late loss and TLR.The TAT group showed less in-stent late loss as compared to the DAT group. This was consistently observed regardless of DES type, lesion length, or diabetic status. However, reduction of late loss by cilostazol did not lead to a significant reduction in TLR.

Distribution of angiographic measures of restenosis after drug-eluting stent implantation.

PubMed

Byrne, R A; Eberle, S; Kastrati, A; Dibra, A; Ndrepepa, G; Iijima, R; Mehilli, J; Schömig, A

2009-10-01

A bimodal distribution of measures of restenosis has been demonstrated at 6-8 months after bare metal stent implantation. Drug-eluting stent (DES) treatment has attenuated the impact of certain factors (eg, diabetes) on restenosis but its effect on the distribution of indices of restenosis is not known. To perform a detailed analysis of the metrics of restenosis indices after DES implantation. Design, settings, Prospective observational study of patients undergoing DES implantation (Cypher, sirolimus-eluting stent; or Taxus, paclitaxel-eluting stent) at two German centres, with repeat angiography scheduled at 6-8 months after coronary stenting. In-stent late luminal loss (LLL) and in-segment percentage diameter stenosis (%DS) as determined by quantitative coronary angiography at recatheterisation. Paired cineangiograms were available for 2057 patients. Overall mean (SD) LLL was 0.31 (0.50) mm; mean (SD) %DS was 30.3 (15.7)%. Distribution of both LLL and %DS differed significantly from normal (Kolmogorov-Smirnov test; p<0.001 for each). For both parameters a mixed distribution model better described the data (likelihood ratio test with 3df; p<0.001 for each). This consisted of two normally distributed subpopulations with means (SD) of 0.10 (0.25) mm and 0.69 (0.60) mm for LLL, and means (SD) of 22.2 (8.6)% and 40.1 (16.6)% for %DS. The results were consistent across subgroups of DES type, "on-label" versus "off-label" indication, and presence or absence of diabetes. LLL and %DS at follow-up angiography after DES implantation have a complex mixed distribution that may be accurately represented by a bimodal distribution model. The introduction of DES treatment has not resulted in elimination of a variable propensity to restenosis among subpopulations of patients with stented lesions.

Risk factors for proximal migration of biliary tube stents.

PubMed

Kawaguchi, Yoshiaki; Ogawa, Masami; Kawashima, Yohei; Mizukami, Hajime; Maruno, Atsuko; Ito, Hiroyuki; Mine, Tetsuya

2014-02-07

To analyze the risk factors for biliary stent migration in patients with benign and malignant strictures. Endoscopic stent placement was performed in 396 patients with bile duct stenosis, at our institution, between June 2003 and March 2009. The indications for bile duct stent implantation included common bile duct stone in 190 patients, malignant lesions in 112, chronic pancreatitis in 62, autoimmune pancreatitis in 14, trauma in eight, surgical complications in six, and primary sclerosing cholangitis (PSC) in four. We retrospectively examined the frequency of stent migration, and analyzed the patient factors (disease, whether endoscopic sphincterotomy was performed, location of bile duct stenosis and diameter of the bile duct) and stent characteristics (duration of stent placement, stent type, diameter and length). Moreover, we investigated retrieval methods for migrated stents and their associated success rates. The frequency of tube stent migration in the total patient population was 3.5%. The cases in which tube stent migration occurred included those with common bile duct stones (3/190; 1.6%), malignant lesions (2/112; 1.8%), chronic pancreatitis (4/62; 6.5%), autoimmune pancreatitis (2/14; 14.3%), trauma (1/8; 12.5%), surgical complications (2/6; 33.3%), and PSC (0/4; 0%). The potential risk factors for migration included bile duct stenosis secondary to benign disease such as chronic pancreatitis and autoimmune pancreatitis (P = 0.030); stenosis of the lower bile duct (P = 0.031); bile duct diameter > 10 mm (P = 0.023); duration of stent placement > 1 mo (P = 0.007); use of straight-type stents (P < 0.001); and 10-Fr sized stents (P < 0.001). Retrieval of the migrated stents was successful in all cases. The grasping technique, using a basket or snare, was effective for pig-tailed or thin and straight stents, whereas the guidewire cannulation technique was effective for thick and straight stents. Migration of tube stents within the bile duct is rare but possible, and it is important to determine the risk factors involved in stent migration.

Symptomatic Post Endarterectomy Common Carotid Artery Pseudoaneurysm Treated with Combination of Flow Diverter Implantation and Carotid Stenting

PubMed Central

Imbarrato, Greg; Gordhan, Ajeet

2018-01-01

A 74-year-old male developed cervical carotid artery psuedoaneurysm 8 months after carotid endarterectomy. The patient was successfully managed with dual implantation of flow-diverter and conventional carotid stent. Flow-diverter was placed across the neck of pseudoaneurysm to provide flow diversion while carotid stent was implanted within the lumen of the expanded flow-diverter to approximate and hold the flow diverter proximal and distal to the pseudoaneurysm. Follow-up ultrasonography revealed complete resolution of the pseudoaneurysm. PMID:29535899

Extracranial carotid angioplasty and stenting. Initial results and short-term follow-up.

PubMed

Vozzi, C R; Rodriguez, A O; Paolantonio, D; Smith, J A; Wholey, M H

1997-01-01

Carotid percutaneous transluminal angioplasty, with or without stent implantation, is becoming another therapeutic option for carotid revascularization. To evaluate the feasibility and effectiveness of the technique, from October of 1995 to March of 1997, we performed 24 percutaneous transluminal angioplasty procedures in 22 patients with severe extracranial carotid artery stenosis. Three common carotid and 21 internal carotid arteries were treated, and 19 procedures included stent implantation using nonarticulated PALMAZ stents (P154 and P204). Twelve patients were asymptomatic and 10 patients were symptomatic; 2 of the symptomatic patients had complete obstruction of the internal carotid artery that was successfully recanalized. Technical and angiographic success was achieved in 23 of 24 procedures, with the carotid artery obstruction diminishing from 85.6% +/- 8.5% to 5.7% +/- 3.2% (P < 0.001). Average stenosis length was 12.5 +/- 3.1 mm, and mean time of carotid occlusion during balloon inflation was 11.5 +/- 2.5 seconds. Three patients experienced transitory seizures during the procedure prior to dilation, 1 patient had a minor stroke with complete recovery within 72 hours, and 1 patient had a major stroke and died 45 days after the procedure. Clinical follow-up was achieved in all patients (mean, 10.5 +/- 7.2 months) and angiographic follow-up in 16 patients (mean, 6.3 +/- 1.2 months). The results obtained in this initial experience provide adequate support to continue further evaluation of this new therapeutic strategy.

Delayed complications after flow-diverter stenting: reactive in-stent stenosis and creeping stents.

PubMed

Cohen, José E; Gomori, John Moshe; Moscovici, Samuel; Leker, Ronen R; Itshayek, Eyal

2014-07-01

We assessed the frequency and severity of changes in stent configuration and location after the treatment of intracranial aneurysms, and patterns of in-stent stenosis. We retrospectively reviewed data for consecutive aneurysm patients managed with endovascular implantation of flow-diverter stents (Silk Flow Diverter [Balt Extrusion, Montmorency, France] and Pipeline Embolization Device [ev3/Coviden, Minneapolis, MN, USA]) from October 2011 to July 2012. Routine 2, 6, 9-12, and 16-20 month follow-up angiograms were compared, with a focus on changes in stent configuration and location from immediately after deployment to angiographic follow-up, and the incidence and development of in-stent stenosis. Thirty-four patients with 42 aneurysms met inclusion criteria. The Silk device was implanted in 16 patients (47%, single device in 15), the Pipeline device in 18 (53%, single device in 16). On first follow-up angiography, in-stent stenosis was observed in 38% of Silk devices and 39% of Pipeline devices. In-stent stenosis was asymptomatic in 12 of 13 patients. One woman presented with transient ischemic attacks and required stent angioplasty due to end tapering and mild, diffuse in-stent stenosis. Configuration and location changes, including stent creeping and end tapering were seen in 2/16 patients (13%) with Silk devices, and 0/18 patients with Pipeline devices. We describe stent creeping and end tapering as unusual findings with the potential for delayed clinical complications. In-stent stenosis, with a unique behavior, is a frequent angiographic finding observed after flow-diverter stent implant. The stenosis is usually asymptomatic; however, close clinical and angiographic monitoring is mandatory for individualized management. Copyright © 2013 Elsevier Ltd. All rights reserved.

Advantages and disadvantages of biodegradable platforms in drug eluting stents.

PubMed

Rodriguez-Granillo, Agustina; Rubilar, Bibiana; Rodriguez-Granillo, Gaston; Rodriguez, Alfredo E

2011-03-26

Coronary angioplasty with drug-eluting stent (DES) implantation is currently the most common stent procedure worldwide. Since the introduction of DES, coronary restenosis as well as the incidence of target vessel and target lesion revascularization have been significantly reduced. However, the incidence of very late stent thrombosis beyond the first year after stent deployment has more commonly been linked to DES than to bare-metal stent (BMS) implantation. Several factors have been associated with very late stent thrombosis after DES implantation, such as delayed healing, inflammation, stent mal-apposition and endothelial dysfunction. Some of these adverse events were associated with the presence of durable polymers, which were essential to allow the elution of the immunosuppressive drug in the first DES designs. The introduction of erodable polymers in DES technology has provided the potential to complete the degradation of the polymer simultaneously or immediately after the release of the immunosuppressive drug, after which a BMS remains in place. Several DES designs with biodegradable (BIO) polymers have been introduced in preclinical and clinical studies, including randomized trials. In this review, we analyze the clinical results from 6 observational and randomized studies with BIO polymers and discuss advantages and disadvantages of this new technology.

Clinical use of intracoronary imaging. Part 1: guidance and optimization of coronary interventions. An expert consensus document of the European Association of Percutaneous Cardiovascular Interventions: Endorsed by the Chinese Society of Cardiology.

PubMed

Räber, Lorenz; Mintz, Gary S; Koskinas, Konstantinos C; Johnson, Thomas W; Holm, Niels R; Onuma, Yoshinubo; Radu, Maria D; Joner, Michael; Yu, Bo; Jia, Haibo; Menevau, Nicolas; de la Torre Hernandez, Jose M; Escaned, Javier; Hill, Jonathan; Prati, Francesco; Colombo, Antonio; di Mario, Carlo; Regar, Evelyn; Capodanno, Davide; Wijns, William; Byrne, Robert A; Guagliumi, Giulio

2018-05-22

This Consensus Document is the first of two reports summarizing the views of an expert panel organized by the European Association of Percutaneous Cardiovascular Interventions (EAPCI) on the clinical use of intracoronary imaging including intravascular ultrasound (IVUS) and optical coherence tomography (OCT). The first document appraises the role of intracoronary imaging to guide percutaneous coronary interventions (PCIs) in clinical practice. Current evidence regarding the impact of intracoronary imaging guidance on cardiovascular outcomes is summarized, and patients or lesions most likely to derive clinical benefit from an imaging-guided intervention are identified. The relevance of the use of IVUS or OCT prior to PCI for optimizing stent sizing (stent length and diameter) and planning the procedural strategy is discussed. Regarding post-implantation imaging, the consensus group recommends key parameters that characterize an optimal PCI result and provides cut-offs to guide corrective measures and optimize the stenting result. Moreover, routine performance of intracoronary imaging in patients with stent failure (restenosis or stent thrombosis) is recommended. Finally, strengths and limitations of IVUS and OCT for guiding PCI and assessing stent failures and areas that warrant further research are critically discussed.

Effects of minute misregistrations of prefabricated markers for image-guided dental implant surgery: an analytical evaluation.

PubMed

Rußig, Lorenz L; Schulze, Ralf K W

2013-12-01

The goal of the present study was to develop a theoretical analysis of errors in implant position, which can occur owing to minute registration errors of a reference marker in a cone beam computed tomography volume when inserting an implant with a surgical stent. A virtual dental-arch model was created using anatomic data derived from the literature. Basic trigonometry was used to compute effects of defined minute registration errors of only voxel size. The errors occurring at the implant's neck and apex both in horizontal as in vertical direction were computed for mean ±95%-confidence intervals of jaw width and length and typical implant lengths (8, 10 and 12 mm). Largest errors occur in vertical direction for larger voxel sizes and for greater arch dimensions. For a 10 mm implant in the frontal region, these can amount to a mean of 0.716 mm (range: 0.201-1.533 mm). Horizontal errors at the neck are negligible, with a mean overall deviation of 0.009 mm (range: 0.001-0.034 mm). Errors increase with distance to the registration marker and voxel size and are affected by implant length. Our study shows that minute and realistic errors occurring in the automated registration of a reference object have an impact on the implant's position and angulation. These errors occur in the fundamental initial step in the long planning chain; thus, they are critical and should be made aware to users of these systems. © 2012 John Wiley & Sons A/S.

Outcomes of spot stenting versus long stenting after intentional subintimal approach for long chronic total occlusions of the femoropopliteal artery.

PubMed

Hong, Sung-Jin; Ko, Young-Guk; Shin, Dong-Ho; Kim, Jung-Sun; Kim, Byeong-Keuk; Choi, Donghoon; Hong, Myeong-Ki; Jang, Yangsoo

2015-03-01

This study sought to compare the outcomes of spot stenting versus long stenting after intentional subintimal approach for long femoropopliteal chronic total occlusions (CTO). The optimal stenting strategy following the subintimal recanalization of long femoropopliteal chronic total occlusions has not been investigated. A total of 196 limbs in 163 patients, implanted with bare nitinol stents after subintimal approach in long femoropopliteal occlusions (lesion length 25 ± 8 cm), were retrospectively analyzed. The primary patency was compared between spot stenting (n = 129) and long stenting (n = 67). Baseline characteristics and immediate procedural results were similar between groups. Adjusted-primary patency (47% vs. 77%, p < 0.001) and adjusted-freedom from target lesion revascularization (52% vs. 84%, p < 0.001) at 2 years were significantly lower in the long stenting group than in the spot stenting group. The incidence of stent fracture, fracture type, and restenosis pattern did not differ between groups. Long stenting was an independent predictor of restenosis (hazard ratio [HR]: 2.0) along with other risk factors such as nonuse of clopidogrel (HR: 3.3) or cilostazol (HR: 2.2), small stent diameter (HR: 0.6), poor run-off (HR: 1.9), and post-procedural ankle-brachial index (HR: 0.1). Compared with spot stenting after adjustment using inverse probability of treatment weighting, long stenting, especially involving the P2 or P3 segment of the popliteal artery, was independently associated with 7.5-fold increases in restenosis risk (p < 0.001). The primary patency was significantly higher with spot stenting than with long stenting following subintimal approach for long femoropopliteal chronic total occlusions. The risk of restenosis was especially higher when long stenting was extended to the distal popliteal artery. Copyright © 2015 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Prediction of advanced endovascular stent graft rotation and its associated morbidity and mortality.

PubMed

Crawford, Sean A; Sanford, Ryan M; Doyle, Matthew G; Wheatcroft, Mark; Amon, Cristina H; Forbes, Thomas L

2018-01-29

Advanced endovascular aneurysm repair (EVAR) with fenestrated and branched stent grafts is increasingly being used to repair complex aortic aneurysms; however, these devices can rotate unpredictably during deployment, leading to device misalignment. The objectives of this study were to quantify the short-term clinical outcomes in patients with intraoperative stent graft rotation and to identify quantitative anatomic markers of the arterial geometry that can predict stent graft rotation preoperatively. A prospective study evaluating all patients undergoing advanced EVAR was conducted at two university-affiliated hospitals between November 2015 and December 2016. Stent graft rotation (defined as ≥10 degrees) was measured on intraoperative fluoroscopic video of the deployment sequence. Standard preoperative computed tomography angiography imaging was used to calculate the geometric properties of the arterial anatomy. Any in-hospital and 30-day complications were prospectively documented, and a composite outcome of any end-organ ischemia or death was used as the primary end point. Thirty-nine patients undergoing advanced EVAR were enrolled in the study with a mean age of 75 years (interquartile range [IQR], 71-80 years) and a mean aneurysm diameter of 64 mm (IQR, 59-65 mm). The incidence of stent graft rotation was 37% (n = 14), with a mean rotation of 25 degrees (IQR, 21-28 degrees). A nominal logistic regression model identified iliac artery torsion, volume of iliac artery calcification, and stent graft length as the primary predictive factors. The total net torsion and the total volume of calcific plaque were higher in patients with stent graft rotation, 8.9 ± 0.8 mm -1 vs 4.1 ± 0.5 mm -1 (P < .0001) and 1054 ± 144 mm 3 vs 525 ± 83 mm 3 (P < .01), respectively. The length of the implanted stent grafts was also higher in patients with intraoperative rotation, 172 ± 9 mm vs 156 ± 8 mm (P < .01). The composite outcome of any end-organ ischemia or death was also substantially higher in patients with stent graft rotation (36% vs 0%; P = .004). In addition, patients with stent graft rotation had significantly higher combined rates of type Ib and type III endoleaks (43% vs 8%; P = .03). Patients with intraoperative stent graft rotation have a significantly higher rate of severe postoperative complications, and this is strongly associated with higher levels of iliac artery torsion, calcification, and stent graft length. These findings suggest that preoperative quantitative analysis of iliac artery torsion and calcification may improve risk stratification of patients before advanced EVAR. Copyright © 2017 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

First Report of the Resolute Onyx 2.0-mm Zotarolimus-Eluting Stent for the Treatment of Coronary Lesions With Very Small Reference Vessel Diameter.

PubMed

Price, Matthew J; Saito, Shigeru; Shlofmitz, Richard A; Spriggs, Douglas J; Attubato, Michael; McLaurin, Brent; Popma Almonacid, Alexandra; Brar, Sandeep; Liu, Minglei; Moe, Elizabeth; Mehran, Roxana

2017-07-24

The aim of this study was to explore the safety and efficacy of a dedicated drug-eluting stent for the treatment of coronary lesions with very small reference vessel diameter (RVD). Smaller RVD is associated with increased risk for restenosis and target lesion failure (TLF) after stent implantation. This was a prospective, single-arm, multicenter trial of the Resolute Onyx 2.0-mm zotarolimus-eluting stent. The primary endpoint was 12-month TLF, which was compared with a pre-specified performance goal. Subjects with stable or unstable angina or ischemia, target lesions ≤27 mm in length, and RVD ≥2.0 and <2.25 mm were eligible for enrollment. A subset of subjects underwent follow-up angiography at 13 months post-procedure. A total of 101 subjects with 104 lesions were enrolled. The mean age was 67.3 ± 9.6 years, 47% of subjects had diabetes, the mean lesion length was 12.6 ± 6.3 mm, and the mean RVD was 1.91 ± 0.26 mm. The rate of TLF at 12 months was 5.0%, fulfilling the pre-specified performance goal of 19% (p < 0.001). The rates of target lesion revascularization and target vessel myocardial infarction were 2.0% and 3.0%, respectively. There were no episodes of stent thrombosis. In-stent late lumen loss was 0.26 ± 0.48 mm, and the rate of binary restenosis was 12.0%. In this first report of a drug-eluting stent with a dedicated size to treat lesions with RVD <2.25 mm, the Resolute Onyx 2.0-mm zotarolimus-eluting stent was associated with a low rate of TLF and late lumen loss, without a signal for stent thrombosis. This novel-sized drug-eluting stent appears to be a feasible option for the treatment of coronary lesions in extremely small vessels. (Medtronic Resolute Onyx 2.0 mm Clinical Study; NCT02412501). Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Resolution of Metallic Biliary Stent Allergic Reaction After Partial Stent Removal in a Patient with Nickel Sensitivity.

PubMed

Esparaz, Anthony M; Ahmed, Muneeb

2017-07-01

Local and systemic reactions to implanted metallic devices, particularly to those containing nickel, are well documented. Metal ions are released due to exposure of the metal to blood, proteins, other body fluids, and sheer mechanical stress. Metal ions then complex with native proteins and become antigens, which can elicit hypersensitivity reactions. Another case report depicts a specific allergic complication (early stent occlusion) related to metallic biliary stent implantation. We present a case of allergic symptoms, associated with eating, in a patient who developed nickel sensitivity after biliary metal stent placement confirmed by allergic skin testing to the same metallic biliary stent placed one year earlier. Symptoms resolved following partial removal of the non-epithelialized portion of the biliary stent.

[Fine mesh metal endoprostheses for treatment of extensive cervical and intrathoracic tracheomalacia].

PubMed

Wilmes, E; Berger, H; Dienemann, H; Jolk, A

1994-01-01

The treatment of tracheal stenoses caused by tracheomalacia is mainly carried out by means of sleeve resection, tracheopexy with ring support or other tracheoplastic operative procedures. If patients cannot be treated by surgical operative strategies, conventional stents are usually used to dilate the trachea. The use of a self-expanding elastic metal prosthesis in 5 patients with tracheal airway obstruction caused by tracheomalacia proved to be a true alternative in the therapy of tracheobronchial stenoses. We report on the long term use of 5 patients with tracheal stenoses treated by implantation of elastic metal wallstents. The implantation of the stents resulted in immediate improvement in respiratory function in all 5 patients. None of the patients experienced complications secondary to the stent placement. The stents were well tolerated (long-time follow-up 26 months). The implantation of self-expanding metal stents type "wallstent" seems to offer alternative possibilities for the treatment of tracheomalacia.

Evolution of the degradation mechanism of pure zinc stent in the one-year study of rabbit abdominal aorta model.

PubMed

Yang, Hongtao; Wang, Cong; Liu, Chaoqiang; Chen, Houwen; Wu, Yifan; Han, Jintao; Jia, Zichang; Lin, Wenjiao; Zhang, Deyuan; Li, Wenting; Yuan, Wei; Guo, Hui; Li, Huafang; Yang, Guangxin; Kong, Deling; Zhu, Donghui; Takashima, Kazuki; Ruan, Liqun; Nie, Jianfeng; Li, Xuan; Zheng, Yufeng

2017-11-01

In the present study, pure zinc stents were implanted into the abdominal aorta of rabbits for 12 months. Multiscale analysis including micro-CT, scanning electron microscopy (SEM), scanning transmission electron microscopy (STEM) and histological stainings was performed to reveal the fundamental degradation mechanism of the pure zinc stent and its biocompatibility. The pure zinc stent was able to maintain mechanical integrity for 6 months and degraded 41.75 ± 29.72% of stent volume after 12 months implantation. No severe inflammation, platelet aggregation, thrombosis formation or obvious intimal hyperplasia was observed at all time points after implantation. The degradation of the zinc stent played a beneficial role in the artery remodeling and healing process. The evolution of the degradation mechanism of pure zinc stents with time was revealed as follows: Before endothelialization, dynamic blood flow dominated the degradation of pure zinc stent, creating a uniform corrosion mode; After endothelialization, the degradation of pure zinc stent depended on the diffusion of water molecules, hydrophilic solutes and ions which led to localized corrosion. Zinc phosphate generated in blood flow transformed into zinc oxide and small amounts of calcium phosphate during the conversion of degradation microenvironment. The favorable physiological degradation behavior makes zinc a promising candidate for future stent applications. Copyright © 2017 Elsevier Ltd. All rights reserved.

[The thermoformable spiral metallic stents in the treatment of localized ureteral stenosis: an alternative to JJ stent? Prospective multicenter study].

PubMed

Bonniol, R; Meria, P; Safsaf, A; Albouy, B; Sibert, L

2011-06-01

Evaluation of the effectiveness and tolerance of thermoformable metallic spiral stents Memokath(®) 051 (Bard, Pnn Medical) in the treatment of localized ureteral stenosis in non-operable patients who have JJ ureteral stents. Prospective, descriptive and multicenter study of patients with ureteral strictures treated with metallic ureteral stents Memokath(®) 051. Assessment criteria (recurrent stenotic, permeability, tolerance) were measured by clinical, biological and radiological examination at 1 month, and then every 3 months. Fifteen stents (average length: 9.15 cm, range 6-15 cm) were implanted in 14 patients (mean age: 55 years, range: 38-72 years) with secondary suspended ureteral stenosis during 2 years in two centers. The median follow-up was 11 months (range 6 to 24 months). Technical difficulty was observed with two patients. Stents are still up in four patients. The stenosis recurred in four patients with spontaneous progression of stenosis but without endoprosthetics tissue invasion. Two and three migration were observed with spontaneous expulsions. Two lower urinary infections and one high occurred, resolved on antibiotic therapy, no inlay or hematuria, no pain (mean VAS score=3/10) or urinary disorders of the lower unit have been identified. Stents Memokath(®) 051 are well tolered and seem to position themselves as an interesting alternative to JJ ureteral stent in some frails patients. The refinement of contraindication should help to improve the stent's efficacity and to reduce the risk of migration and expulsion. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

Microparticles and blood cells induce procoagulant activity via phosphatidylserine exposure in NSTEMI patients following stent implantation.

PubMed

Wang, Lixiu; Bi, Yayan; Cao, Muhua; Ma, Ruishuang; Wu, Xiaoming; Zhang, Yan; Ding, Wenbo; Liu, Yan; Yu, Qian; Zhang, Yingqian; Jiang, Hua; Sun, Yingchun; Tong, Dongxia; Guo, Li; Dong, Zengxiang; Tian, Ye; Kou, Junjie; Shi, Jialan

2016-11-15

Relatively little is known about the role of phosphatidylserine (PS) in procoagulant activity (PCA) in patients with non-ST-elevated myocardial infarction (NSTEMI) after stent implantation. This study was designed to evaluate whether exposed PS on microparticles (MPs) and blood cells were involved in the hypercoagulable state in NSTEMI patients with stent implantation. NSTEMI patients (n=90) and healthy controls (n=20) were included in our study. PS exposure on MPs and blood cells was analyzed with flow cytometer and confocal microscope. PCA was evaluated by clotting time, purified coagulation complex assays and fibrin production assays. Baseline levels of MPs and PS + blood cells were significantly higher (P<0.001) in the patients than in controls. After stent implantation, a remarkable increase was observed in both MPs and PS + blood cells. Specifically, PS + MPs, PS + platelets and erythrocytes peaked at 18h following stent implantation, while PS + leukocytes peaked on day 2. In addition, circulating MPs (mostly derived from platelets, leukocytes, erythrocytes and endothelial cells) cooperating with PS + blood cells, contributed to markedly shortened coagulation time and markedly increased FXa/thrombin/fibrin (all P<0.01) generation in patient group. Moreover, blockade of exposed PS on MPs and cells with lactadherin inhibited PCA by approximately 70%. Our results suggest that PS + MPs and blood cells play a procoagulant role in NSTEMI patients following stent implantation. Blockade of PS could become a novel therapeutic modality for the prevention of thrombosis in these patients. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Stent-based nitric oxide delivery reducing neointimal proliferation in a porcine carotid overstretch injury model.

PubMed

Hou, Dongming; Narciso, Hugh; Kamdar, Kirti; Zhang, Ping; Barclay, Bruce; March, Keith L

2005-01-01

The effects of nitric acid (NO) on vessel response to injury include the inhibition of platelet adhesion, platelet aggregation, leukocyte adhesion and smooth muscle cell proliferation. Releasing NO from a stent might reduce the clinical problem of restenosis. The present study was designed to examine whether an NO-eluting covered stent can prevent neointimal formation in a porcine carotid overstretch injury model. The interior of a self-expanding polytetrafluoroethylene (ePTFE)-covered aSpire stent was coated with silicone, which contained 23.6 microg or 54.5 microg sodium nitroprusside (SNP, NO-releasing compound). The stent was implanted into carotid artery. Six pigs were implanted with stents, one high-dose SNP and one uncoated control, following balloon overstretch injury of the carotid artery with a balloon-to-artery ratio of 1.3:1. No local or systemic toxicity was evidenced in the six pigs after carotid artery implantation with either low- or high-dose stents within a week. At day 28, the mean intimal thickness was 0.12 +/- 0.05 mm for NO-eluting stents and 0.43 +/- 0.09 mm for uncoated stents (p = 0.008). The mean neointimal area was reduced from 2.40 +/- 0.39 mm2 for control stents to 0.49 +/- 0.16 mm2 for NO-eluting stents (p < 0.0001), which resulted in a 24% reduction of angiographic vessel narrowing. The NO-eluting ePTFE-covered stent is feasible and effectively reduces in-stent neointimal hyperplasia at 28 days in a porcine carotid overstretch model.

Incidence of adverse cardiac events 5 years after polymer-free sirolimus eluting stent implantation: Results from the prospective Bad Berka Yukon Choice™ registry.

PubMed

Ohlow, Marc-Alexander; von Korn, Hubertus; Gunkel, Oliver; Farah, Ahmed; Fuhrmann, Joerg T; Lauer, Bernward

2014-12-01

Drug-eluting stents (DES) constitute a major achievement in preventing re-stenosis, concerns remain regarding the increased inflammatory responses associated with the polymers used. This analysis focuses on outcomes in patients receiving the polymer-free sirolimus-eluting stent system YUKON-Choice (Yukon-DES, Translumina, Germany). From 01/2006-09/2008 all patients receiving Yukon-DES (≥2.5 mm diameter) were prospectively enrolled in our registry. The primary endpoint was long-term major adverse cardiac events (MACE). 701 patients were included in our registry. Mean age was 65.7 ± 10 years (73% male gender, 35.5% diabetes, and 32.2% acute coronary syndrome). 76% of the lesions were of Type B2/C. Lesion length was 24.6 ± 5.2 mm and mean stent diameter was 2.8 ± 0.4 mm. A total of 511 pts (72%) underwent 6-months angiographic follow-up, target vessel revascularization was noted in 23.5%. At 5 years clinical outcomes were: cardiac death 5.8%; myocardial infarction 3.4%; and TVR 24.6%. The incidence of MACE differed significantly between "on-label" and "off-label" indications (14.8% vs. 40.8% MACE; P < 0.001). Incidence of definitive/probable stent thrombosis (ST) was 1.14% (8/701); very late (>1 year) ST occurred in 0.29%. Our data suggests that the implantation of the sirolimus-coated polymer-free YUKON-DES is safe and feasible with a very low incidence of ST in this real world patient cohort with high percentage of diabetes and small vessels. © 2013 Wiley Periodicals, Inc.

Preservation of keratinized mucosa around implants using a prefabricated implant-retained stent: a case-control study

PubMed Central

2016-01-01

Purpose The aim of this study was to clinically assess the impact of a prefabricated implant-retained stent clipped over healing abutments on the preservation of keratinized mucosa around implants after implant surgery, and to compare it with horizontal external mattress sutures. Methods A total of 50 patients were enrolled in this study. In the test group, a prefabricated implant-retained stent was clipped on the healing abutment after implant surgery to replace the keratinized tissue bucco-apically. In the control group, horizontal external mattress sutures were applied instead of using a stent. After the surgical procedure, the width of the buccal keratinized mucosa was measured at the mesial, middle, and distal aspects of the healing abutment. The change in the width of the buccal keratinized mucosa was assessed at 1 and 3 months. Results Healing was uneventful in both groups. The difference of width between baseline and 1 month was −0.26±0.85 mm in the test group, without any statistical significance (P=0.137). Meanwhile, the corresponding difference in the control group was −0.74±0.73 mm and it showed statistical significance (P<0.001). The difference of width between baseline and 3 months was −0.57±0.97 mm in the test group and −0.86±0.71 mm in the control group. These reductions were statistically significant (P<0.05); however, there was no difference between the 2 groups. Conclusions Using a prefabricated implant-retained stent was shown to be effective in the preservation of the keratinized mucosa around implants and it was simple and straightforward in comparison to the horizontal external mattress suture technique. PMID:27800215

A review on biodegradable materials for cardiovascular stent application

NASA Astrophysics Data System (ADS)

Hou, Li-Da; Li, Zhen; Pan, Yu; Sabir, MuhammadIqbal; Zheng, Yu-Feng; Li, Li

2016-09-01

A stent is a medical device designed to serve as a temporary or permanent internal scaffold to maintain or increase the lumen of a body conduit. The researchers and engineers diverted to investigate biodegradable materials due to the limitation of metallic materials in stent application such as stent restenosis which requires prolonged anti platelet therapy, often result in smaller lumen after implantation and obstruct re-stenting treatments. Biomedical implants with temporary function for the vascular intervention are extensively studied in recent years. The rationale for biodegradable stent is to provide the support for the vessel in predicted period of time and then degrading into biocompatible constituent. The degradation of stent makes the re-stenting possible after several months and also ameliorates the vessel wall quality. The present article focuses on the biodegradable materials for the cardiovascular stent. The objective of this review is to describe the possible biodegradable materials for stent and their properties such as design criteria, degradation behavior, drawbacks and advantages with their recent clinical and preclinical trials.

Double Lumen Polyamide Tube-stent for the Treatment of Recurrent Postcorrosive Esophageal Stenosis.

PubMed

Woynarowski, Marek; Dądalski, Maciej; Wojno, Violetta; Teisseyre, Mikołaj; Hurkała, Leszek; Płowiecki, Emil

2017-05-01

This article presents the results of endoscopic treatment for recurrent postcorrosive esophageal stenosis with a tube-stent developed at our institution. The tube-stent was implanted in 5 children with corrosive esophageal injury at the age of 2 to 8.5 years after 7 to 64 dilatation sessions during 5 to 118 months. In total, 13 tube-stents were implanted. One patient had undergone 9 procedures during 2.5 years and the tube-stent remained in place for 14 to 250 days. This patient was tube-stent-dependent due to the lack of any possibility of surgical reconstruction. Two patients had the tube-stent removed after 150 to 205 days and they remain free from esophageal restenosis. One patient did not tolerate the tube-stent, evacuated it after 1 day and was referred for surgical esophagus replacement. One patient is currently still being treated with the tube-stent. Tube-stent was well tolerated and it may be effective in children with recurrent critical postcorrosive esophageal stenosis.

Effects of plaque lengths on stent surface roughness.

PubMed

Syaifudin, Achmad; Takeda, Ryo; Sasaki, Katsuhiko

2015-01-01

The physical properties of the stent surface influence the effectiveness of vascular disease treatment after stent deployment. During the expanding process, the stent acquires high-level deformation that could alter either its microstructure or the magnitude of surface roughness. This paper constructed a finite element simulation to observe the changes in surface roughness during the stenting process. Structural transient dynamic analysis was performed using ANSYS, to identify the deformation after the stent is placed in a blood vessel. Two types of bare metal stents are studied: a Palmaz type and a Sinusoidal type. The relationship between plaque length and the changes in surface roughness was investigated by utilizing three different length of plaque; plaque length longer than the stent, shorter than the stent and the same length as the stent. In order to reduce computational time, 3D cyclical and translational symmetry was implemented into the FE model. The material models used was defined as a multilinear isotropic for stent and hyperelastic for the balloon, plaque and vessel wall. The correlation between the plastic deformation and the changes in surface roughness was obtained by intermittent pure tensile test using specimen whose chemical composition was similar to that of actual stent material. As the plastic strain is achieved from FE simulation, the surface roughness can be assessed thoroughly. The study found that the plaque size relative to stent length significantly influenced the critical changes in surface roughness. It was found that the length of stent which is equal to the plaque length was preferable due to the fact that it generated only moderate change in surface roughness. This effect was less influential to the Sinusoidal stent.

Evaluation of clinical outcomes in patients undergoing dual vessel percutaneous coronary intervention using sirolimus-eluting coronary stent system in India.

PubMed

Chandwani, Prakash; Prajapati, Jayesh; Porwal, Sanjay; Khambhati, Bhavesh; Thakkar, Ashok

2015-02-01

Coronary artery disease is the most common catastrophic disease in India. The safety and effectiveness of dual vessel sirolimus-eluting stent (SES) implantation (used as an intervention in CAD) is currently unknown in Indian population. The purpose of this study was to investigate one year clinical outcomes of patients with dual vessel coronary artery disease after implantation of the Supralimus-Core SES, in a "real-world" setting. We evaluated 60 patients between April-2011 and August-2012, who underwent dual vessel percutaneous coronary intervention (PCI) with the Supralimus-Core SES implantation at the same index procedure. Dual vessels were defined as involvement of two major epicardial vessels (right, left anterior descending, circumflex, or left main coronary arteries) or one major epicardial vessel and a branch (≥2.5 mm in diameter) originating from another major epicardial vessel. The primary endpoint was target lesion failure (TLF) defined as the composite of cardiac death, myocardial infarction (MI), and clinically-driven target lesion revascularization (TLR) at one year. Secondary endpoint included combined (definite, probable and possible) stent thrombosis (ST). A total of 120 lesions were treated in 60 enrolled patients (mean age 56.0±9.2 y; 80.0% male) with average stent length of 23.1±8.5 mm. Among 60 patients, diabetes, hypertension and hypercholesterolemia were present in 15 (25.0%), 22 (36.7%) and 25 (41.7%) patients respectively. Indications for PCI were unstable angina in 30 (50.0%) patients and stable angina in 11 (18.3%) patients. Overall, 40 (33.3%) lesions were classified as complex (American College of Cardiology/American Heart Association type B2/C). The cumulative TLF rate was 5.0% (n=3) at one year. Cardiac death, MI and clinically-driven TLR occurred in 1 (1.7%), 0 (0%) and 2 (3.3%) patients, respectively at one year follow-up. The Kaplan-Meier curve of the freedom from overall events at one year was 95.0%. According to the Academic Research Consortium definition, there were no events of stent thrombosis during one year. Our study shows that, dual vessel Supralimus-Core SES implantation allows safe and effective treatment with low rates of TLF at one year follow-up in Indian population.

Covered Biodegradable Stent: New Therapeutic Option for the Management of Esophageal Perforation or Anastomotic Leak

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cerna, Marie; Koecher, Martin, E-mail: martin.kocher@seznam.cz; Valek, Vlastimil

2011-12-15

Purpose: This study was designed to evaluate our experience with the treatment of postoperative anastomotic leaks and benign esophageal perforations with covered biodegradable stents. Materials and Methods: From 2008 to 2010, we treated five men with either an anastomotic leak or benign esophageal perforation by implanting of covered biodegradable Ella-BD stents. The average age of the patients was 60 (range, 38-74) years. Postoperative anastomotic leaks were treated in four patients (1 after esophagectomy, 1 after resection of diverticulum, 2 after gastrectomy). In one patient, perforation occurred as a complication of the treatment of an esophageal rupture (which occurred during amore » balloon dilatation of benign stenosis) with a metallic stent. Results: Seven covered biodegradable stents were implanted in five patients. Primary technical success was 100%. Clinical success (leak sealing) was achieved in four of the five patients (80%). Stent migration occurred in three patients. In two of these patients, the leak had been sealed by the time of stent migration, therefore no reintervention was necessary. In one patient an additional stent had to be implanted. Conclusion: The use of biodegradable covered stents for the treatment of anastomotic leaks or esophageal perforations is technically feasible and safe. The initial results are promising; however, larger number of patients will be required to evaluate the capability of these biodegradable stents in the future. The use of biodegradable material for coverage of the stent is essential.« less

An argument for the use of multiple segment stents in curved arteries.

PubMed

Kasiri, Saeid; Kelly, Daniel J

2011-08-01

Stenting of curved arteries is generally perceived to be more challenging than straight vessels. Conceptually implanting multiple shorter stents rather than a single longer stent into such a curved artery represents a promising concept, but little is known about the impact of such an approach. The objective of this study is to evaluate the effectiveness of using a multiple segment stent rather than a single long stent to dilate a curved artery using the finite element method. A double segment stent (DSS) and a single segment stent (SSS) were modeled. The stents were compared when expanded into a model of a curved artery. The model predicts that the DSS provides higher flexibility, more conformity, and lower recoil in comparison to the SSS. The volume of arterial tissue experiencing high levels of stress due to stent implantation is also reduced for the DSS. It is suggested that a multiple segment stenting system is a potential solution to the problem of higher rates of in-stent restenosis in curved arteries and mechanically challenging environments.

Optical coherence tomography compared with intravascular ultrasound and with angiography to guide coronary stent implantation (ILUMIEN III: OPTIMIZE PCI): a randomised controlled trial.

PubMed

Ali, Ziad A; Maehara, Akiko; Généreux, Philippe; Shlofmitz, Richard A; Fabbiocchi, Franco; Nazif, Tamim M; Guagliumi, Giulio; Meraj, Perwaiz M; Alfonso, Fernando; Samady, Habib; Akasaka, Takashi; Carlson, Eric B; Leesar, Massoud A; Matsumura, Mitsuaki; Ozan, Melek Ozgu; Mintz, Gary S; Ben-Yehuda, Ori; Stone, Gregg W

2016-11-26

Percutaneous coronary intervention (PCI) is most commonly guided by angiography alone. Intravascular ultrasound (IVUS) guidance has been shown to reduce major adverse cardiovascular events (MACE) after PCI, principally by resulting in a larger postprocedure lumen than with angiographic guidance. Optical coherence tomography (OCT) provides higher resolution imaging than does IVUS, although findings from some studies suggest that it might lead to smaller luminal diameters after stent implantation. We sought to establish whether or not a novel OCT-based stent sizing strategy would result in a minimum stent area similar to or better than that achieved with IVUS guidance and better than that achieved with angiography guidance alone. In this randomised controlled trial, we recruited patients aged 18 years or older undergoing PCI from 29 hospitals in eight countries. Eligible patients had one or more target lesions located in a native coronary artery with a visually estimated reference vessel diameter of 2·25-3·50 mm and a length of less than 40 mm. We excluded patients with left main or ostial right coronary artery stenoses, bypass graft stenoses, chronic total occlusions, planned two-stent bifurcations, and in-stent restenosis. Participants were randomly assigned (1:1:1; with use of an interactive web-based system in block sizes of three, stratified by site) to OCT guidance, IVUS guidance, or angiography-guided stent implantation. We did OCT-guided PCI using a specific protocol to establish stent length, diameter, and expansion according to reference segment external elastic lamina measurements. All patients underwent final OCT imaging (operators in the IVUS and angiography groups were masked to the OCT images). The primary efficacy endpoint was post-PCI minimum stent area, measured by OCT at a masked independent core laboratory at completion of enrolment, in all randomly allocated participants who had primary outcome data. The primary safety endpoint was procedural MACE. We tested non-inferiority of OCT guidance to IVUS guidance (with a non-inferiority margin of 1·0 mm 2 ), superiority of OCT guidance to angiography guidance, and superiority of OCT guidance to IVUS guidance, in a hierarchical manner. This trial is registered with ClinicalTrials.gov, number NCT02471586. Between May 13, 2015, and April 5, 2016, we randomly allocated 450 patients (158 [35%] to OCT, 146 [32%] to IVUS, and 146 [32%] to angiography), with 415 final OCT acquisitions analysed for the primary endpoint (140 [34%] in the OCT group, 135 [33%] in the IVUS group, and 140 [34%] in the angiography group). The final median minimum stent area was 5·79 mm 2 (IQR 4·54-7·34) with OCT guidance, 5·89 mm 2 (4·67-7·80) with IVUS guidance, and 5·49 mm 2 (4·39-6·59) with angiography guidance. OCT guidance was non-inferior to IVUS guidance (one-sided 97·5% lower CI -0·70 mm 2 ; p=0·001), but not superior (p=0·42). OCT guidance was also not superior to angiography guidance (p=0·12). We noted procedural MACE in four (3%) of 158 patients in the OCT group, one (1%) of 146 in the IVUS group, and one (1%) of 146 in the angiography group (OCT vs IVUS p=0·37; OCT vs angiography p=0·37). OCT-guided PCI using a specific reference segment external elastic lamina-based stent optimisation strategy was safe and resulted in similar minimum stent area to that of IVUS-guided PCI. These data warrant a large-scale randomised trial to establish whether or not OCT guidance results in superior clinical outcomes to angiography guidance. St Jude Medical. Copyright © 2016 Elsevier Ltd. All rights reserved.

Covered Stent and Coils Embolization of a Pulmonary Artery Pseudoaneurysm After Gunshot Wound

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huet, Nicolas, E-mail: nhuet@chu-grenoble.fr; Rodiere, Mathieu, E-mail: mrodiere@chu-grenoble.fr; Badet, Michel, E-mail: michel.badet@ch-chambery.fr

We report the first case of endovascular covered stent implantation for the treatment of a large pulmonary artery pseudoaneurysm (PAPA) following a right thoracic gunshot wound. After resuscitation and hemodynamic stabilization, a CT angiography was performed to analyze the neck size of the PAPA and its position relative to the branches of the parent artery. Covered stent implantation with additional coil embolization was successfully performed. At the 4-year follow-up, the stents remained patent and there was neither pseudoaneurysm recurrence nor treatment-related complication.

Impact of Stent-to-Vessel Diameter Ratio on Restenosis in the Superficial Femoral Artery After Endovascular Therapy.

PubMed

Kurata, Naoya; Iida, Osamu; Shiraki, Tatsuya; Fujita, Masashi; Masuda, Masaharu; Okamoto, Shin; Ishihara, Takayuki; Nanto, Kiyonori; Kanda, Takashi; Sunaga, Akihiro; Tsujimura, Takuya; Takahara, Mitsuyoshi; Mano, Toshiaki

2018-04-25

Although stent-to-vessel (S/V) diameter ratio has been described as a restenotic factor after superficial femoral artery (SFA) stenting, the reference vessel diameter is commonly measured distally at a healthy site. It remains unclear whether S/V ratio assessed at the lesion site would be more predictive than that assessed distally at a healthy site.Methods and Results:A total of 117 patients (mean age, 73±7 years; 74% male) who underwent successful nitinol stent implantation in SFA lesions (mean lesion length, 172±104 mm) on intravascular ultrasound (IVUS) were retrospectively analyzed. S/V ratio at the proximal and distal healthy site, and at the smallest lesion site, was evaluated on IVUS. One-year restenosis predictors were evaluated on multivariate analysis. Mean S/V diameter ratio on IVUS at proximal and distal healthy sites, and at the lesion site, was 0.98±0.11, 1.02±0.11 and 1.15±0.16, respectively. One-year primary patency was 77%. On multivariate analysis, lesion length (OR, 1.06 per 10-mm increment; P=0.046) and S/V ratio measured at the lesion site (OR, 1.34 per 0.1 increment; P=0.032), but not that at the distal healthy site (OR, 1.05 per 0.1 increment; P=0.705), were significantly associated with 1-year restenosis. S/V ratio assessed on IVUS at the lesion site, but not at the distal healthy site, was independently associated with 1-year restenosis after SFA stenting.

Microbiology and Biofilm Trends of Silicone Lacrimal Implants: Comparing Infected Versus Routinely Removed Stents.

PubMed

Samimi, David B; Ediriwickrema, Lilangi S; Bielory, Brett P; Miller, Darlene; Lee, Wendy; Johnson, Thomas E

To investigate the pathogens and biofilms responsible for clinically significant infection of silicone stents implanted within the lacrimal system. Retrospective review of culture results and patient demographics for all silicone lacrimal stents removed early for clinically significant infection and sent to the Bascom Palmer Microbiology Laboratory through the end of year 2010. As a control, routinely removed, clinically noninfected stents from the same institution were prospectively sent for culture over a 6-month period. Four clinically infected and 6 clinically noninfected stents showing mucus within the lumen at removal were sent for scanning electron microscopy. Images were randomized and graded by a microbiologist for the presence of organisms, matrix deposits, organisms within matrix, and overall impression of significant biofilm formation. Nineteen stents were included in the study; 100% of clinically infected (n = 10) and noninfected (n = 9) stents were culture positive. Culture positivity for nontuberculous mycobacterium was found in 90% of infected stents and none of the noninfected stents (p < 0.001). Of infected stents, 50% grew Gram-positive organisms compared with 89% of noninfected stents (p = 0.07). Fifty percent of infected versus 67% of noninfected stents were culture positive for Gram-negative organisms (p = 0.46). Electron microscopy of stents revealed organisms consistent with culture results (size, shape) in planktonic and biofilm form. Masked observer image grading revealed a statistically significant higher amount of organism and biofilm on infected versus noninfected specimen. Nontuberculous mycobacteria comprise the primary pathogens responsible for clinically significant infection of silicone stents in the lacrimal system in South Florida. Robust biofilm production by this organism likely plays a role in pathogenesis. Further research into biofilm-related lacrimal implant infection may aid in the development of useful prevention and treatment strategies.

Percutaneous transvenous stent implantation to external iliac vein stenosis in a patient with retroperitoneal fibrosis.

PubMed

Okuyama, Hidenobu; Hirono, Osamu; Ishigaki, Daisuke; Yuki, Koichi; Kubota, Isao

2010-01-01

A 59-year-old man visited our hospital due to right leg edema and right leg pain. Computed tomography revealed that the circumferential enhancement of bilateral external iliac arteries by soft tissue that had similar density as the adjacent psoas muscle and that the right external iliac vein that was constricted by those tissues. The patient was diagnosed as retroperitoneal fibrosis. He underwent stent implantation to the right external iliac vein stenosis and steroid therapy. His right leg edema and pain was immediately improved after the stent implantation and he achieved remission.

Association of neointimal morphology by optical coherence tomography with rupture of neoatherosclerotic plaque very late after coronary stent implantation.

NASA Astrophysics Data System (ADS)

Karanasos, Antonios; Ligthart, Jurgen; Witberg, Karen; Toutouzas, Konstantinos; Daemen, Joost; van Soest, Gijs; Gnanadesigan, Muthukaruppan; van Geuns, Robert-Jan; de Jaegere, Peter; Regar, Evelyn

2013-03-01

Purpose: Neoatherosclerosis within a stent has been recently described as a culprit of late stent failure. We investigated by optical coherence tomography (OCT) the association of neoatherosclerotic plaque morphology with neointimal rupture (NR) and clinical presentation in patients late after coronary stent implantation. Methods: From 1/1/2007 to 31/1/2012, 74 patients from two institutions underwent OCT assessment of a coronary stent implanted at least 18 months prior to OCT study. Native atherosclerosis criteria were used for neointimal characterization. Results: Neoatherosclerosis was observed in 59.5% of the stents (n=44). Stents with neoatherosclerosis were more often associated with symptoms compared to stents without neoatherosclerosis (59.1% acute coronary syndrome (ACS), 25% stable angina (SA), and 15.9% asymptomatic versus 43.3% ACS, 6.7% SA, 50% asymptomatic, p<0.01). Among neoatherosclerotic lesions (n=44), NR was detected in 19 (43.2%) and had higher incidence in ACS (61.5%) than in SA (18.2%) and asymptomatic (14.3%) (p<0.05). Thrombus was detected in all NR cases. Fibrous cap thickness was lower in NR lesions compared to lesions without NR (48+/-21 μm versus 104+/-58μm, p<0.01). Lipid content tended to be higher in lesions with NR (260+/-103° versus 203+/-85°, p=0.051). Lesions with NR had more often dense macrophage infiltration (84.2% versus 44.0%, p<0.05). There were no differences in neovascularization or calcifications between lesions with or without NR. Conclusions: Neoatherosclerosis is frequent and more common among symptomatic patients. Importantly, neointimal rupture is associated with ACS late after stent implantation. Specific morphological characteristics, such as cap thickness and macrophage infiltration are associated with rupture of neoatherosclerotic plaques.

Endovascular abdominal aortic stenosis treatment with the OptiMed self-expandable nitinol stent.

PubMed

Ghazi, Payam; Haji-Zeinali, Ali-Mohammad; Shafiee, Nahid; Qureshi, Shakeel A

2009-10-01

To evaluate the safety and feasibility of self-expandable stents (OptiMed) for treatment of abdominal aortic stenosis in the situations in which the aortic stenosis locates near the origin of celiac, superior mesenteric, renal and inferior mesenteric arteries. Five consecutive patients scheduled for endovascular treatment of abdominal aortic stenosis by self-expandable nitinol stent (Sinus-Aorta/OptiMed) implantation. The diameter of the stent was chosen as 10-30% more than that of the normal portion of the aorta above the stenosis. Long stents of 60 mm or longer were chosen. After stent deployment, balloon postdilation was performed with a balloon in patients with residual gradient > 5 mm Hg. All patients were successfully treated with the OptiMed stents. The balloon predilation was performed in one patient due to severe stenosis. The mean diameter and length of the stents deployed were 20.4 +/- 2.9 (range, 16-24 mm) and 64 +/- 8.9 (range, 60-80 mm), respectively. The balloon postdilation was performed in all cases. The mean diameter of the balloons was 13.6 +/- 1.5 (range, 12-15 mm). The mean diameter of stenosis increased from 4.8 +/- 1.9 to 14.4 +/- 1.8 mm after stent placement. The mean peak systolic gradient decreased from 46.8 +/- 31.5 mm Hg to 0.8 +/- 1.8 mm Hg. During follow-up (22.8 +/- 14.3 months), none of the patients had restenosis within the stent, occlusion of any branches of the aorta, or other related complications. In our small series, we observed that abdominal aortic stenosis can be successfully and effectively treated with OptiMed stents in the situations in which the stenotic segment is located next to the origins of the main visceral branches of abdominal aorta.

Rationale and design of the Patient Related OuTcomes with Endeavor versus Cypher stenting Trial (PROTECT): randomized controlled trial comparing the incidence of stent thrombosis and clinical events after sirolimus or zotarolimus drug-eluting stent implantation.

PubMed

Camenzind, Edoardo; Wijns, William; Mauri, Laura; Boersma, Eric; Parikh, Keyur; Kurowski, Volkhard; Gao, Runlin; Bode, Christoph; Greenwood, John P; Gershlick, Anthony; O'Neill, William; Serruys, Patrick W; Jorissen, Brenda; Steg, P Gabriel

2009-12-01

Drug-eluting stents (DES) reduce restenosis rates compared to bare-metal stents. Most trials using DES enrolled selected patient and lesion subtypes, and primary endpoint focused on angiographic metrics or relatively short-term outcomes. When DES are used in broader types of lesions and patients, important differences may emerge in long-term outcomes between stent types, particularly the incidence of late stent thrombosis. PROTECT is a randomized, open-label trial comparing the long-term safety of the zotarolimus-eluting stent and the sirolimus-eluting stent. The trial has enrolled 8,800 patients representative of those seen in routine clinical practice, undergoing elective, unplanned, or emergency procedures in native coronary arteries in 196 centers in 36 countries. Indications for the procedure and selection of target vessel and lesion characteristics were at the operator's discretion. Procedures could be staged, but no more than 4 target lesions could be treated per patient. Duration of dual antiplatelet therapy was prespecified to achieve similar lengths of treatment in both study arms. The shortest predefined duration was 3 months, as per the manufacturer's instructions. The primary outcome measure is the composite rate of definite and probable stent thrombosis at 3 years, centrally adjudicated using Academic Research Consortium definitions. The main secondary end points are 3-year all-cause mortality, cardiac death, large nonfatal myocardial infarction, and all myocardial infarctions. This large, international, randomized, controlled trial will provide important information on comparative rates of stent thrombosis between 2 different DES systems and safety as assessed by patient-relevant long-term clinical outcomes.

Three-dimensional virtual surgery models for percutaneous coronary intervention (PCI) optimization strategies

NASA Astrophysics Data System (ADS)

Wang, Hujun; Liu, Jinghua; Zheng, Xu; Rong, Xiaohui; Zheng, Xuwei; Peng, Hongyu; Silber-Li, Zhanghua; Li, Mujun; Liu, Liyu

2015-06-01

Percutaneous coronary intervention (PCI), especially coronary stent implantation, has been shown to be an effective treatment for coronary artery disease. However, in-stent restenosis is one of the longstanding unsolvable problems following PCI. Although stents implanted inside narrowed vessels recover normal flux of blood flows, they instantaneously change the wall shear stress (WSS) distribution on the vessel surface. Improper stent implantation positions bring high possibilities of restenosis as it enlarges the low WSS regions and subsequently stimulates more epithelial cell outgrowth on vessel walls. To optimize the stent position for lowering the risk of restenosis, we successfully established a digital three-dimensional (3-D) model based on a real clinical coronary artery and analysed the optimal stenting strategies by computational simulation. Via microfabrication and 3-D printing technology, the digital model was also converted into in vitro microfluidic models with 3-D micro channels. Simultaneously, physicians placed real stents inside them; i.e., they performed “virtual surgeries”. The hydrodynamic experimental results showed that the microfluidic models highly inosculated the simulations. Therefore, our study not only demonstrated that the half-cross stenting strategy could maximally reduce restenosis risks but also indicated that 3-D printing combined with clinical image reconstruction is a promising method for future angiocardiopathy research.

iStent trabecular micro-bypass stent for open-angle glaucoma

PubMed Central

Le, Kim; Saheb, Hady

2014-01-01

Trabecular micro-bypass stents, commonly known as iStents, are micro-invasive glaucoma surgery (MIGS) devices used to treat open-angle glaucoma. Like other MIGS procedures that enhance trabecular outflow, the iStent lowers intraocular pressure (IOP) by creating a direct channel between the anterior chamber and Schlemm’s canal. iStents are typically implanted at the time of phacoemulsification for patients with open-angle glaucoma and visually significant cataracts. This review summarizes the published data regarding the efficacy, safety, and cost considerations of trabecular micro-bypass stents. Most studies found statistically significant reductions in mean IOP and ocular medication use after combined phacoemulsification with single or double iStent implantation. The devices were found to be very safe, with a safety profile similar to that of cataract surgery. Complications were infrequent, with the most common complications being temporary stent obstruction or malposition, which resolved with observation or secondary procedures. Future studies are needed to evaluate long-term outcomes, patient satisfaction, cost effectiveness, and expanded indications. PMID:25284980

Results From the VISIBILITY Iliac Study: Primary and Cohort Outcomes at 9 Months.

PubMed

Rundback, John H; Peeters, Patrick; George, Jon C; Jaff, Michael R; Faries, Peter L

2017-06-01

To evaluate the safety and effectiveness of primary stenting of the common (CIA) or external iliac artery (EIA) using the Visi-Pro Balloon-Expandable Peripheral Stent System for treatment of stenotic, restenotic, or occluded lesions. Between 2011 and 2012, 75 patients (mean age 64.2±8.9 years; 46 men) with Rutherford category 2-4 ischemia and atherosclerotic lesions ≤10 cm in length underwent iliac artery stenting at 17 centers in the United States and Europe. The primary outcome of the study was the major adverse event (MAE) rate at 9 months postprocedure [composite of periprocedural death, in-hospital myocardial infarction, clinically driven target lesion revascularization (CD-TLR), and amputation of the treated limb]. Secondary outcomes included 30-day MAE rate, 9-month primary patency, changes in ankle-brachial index (ABI) and the Walking Impairment Questionnaire at 30 days and 9 months postprocedure, device success, and clinically driven target vessel revascularization (CD-TVR) at 30 days and 9 months. Outcomes in specific patient cohorts (ie, gender, stent location, calcification severity, and lesion grade) were analyzed. Eighty-one stents were implanted in 61 CIA and 15 EIA lesions (41 with moderate/severe calcification). The mean lesion treated length was 29.3±13.9 mm. All devices were successfully deployed. MAE occurred in 3 (4.0%) of 75 subjects at 9 months. Primary patency and freedom from CD-TVR at 9 months were both 95.8%. ABI improved from 0.67±0.14 at baseline to 0.94±0.14 and 0.96±0.16 at 30 days and 9-month follow-up, respectively (p<0.001 for both). There were no differences with respect to any of the analyzed patient characteristics, including gender. Nine-month results of the VISIBILITY Iliac stent study ( ClinicalTrials.gov identifier NCT01402700) demonstrated safety and effectiveness for the treatment of atherosclerotic CIA and EIA lesions with the Visi-Pro stent across all treated cohorts.

iStent with Phacoemulsification versus Phacoemulsification Alone for Patients with Glaucoma and Cataract: A Meta-Analysis

PubMed Central

Malvankar-Mehta, Monali S.; Iordanous, Yiannis; Chen, Yufeng Nancy; Wang, Wan Wendy; Patel, Sangita Shantilal; Costella, John; Hutnik, Cindy M. L.

2015-01-01

Background Minimally invasive glaucoma surgeries (MIGS) have attracted significant attention, as they have been reported to lower intra-ocular pressure (IOP) and have an excellent safety profile. The iStent is an example of a minimally invasive glaucoma device that has received particular attention due to its early and wide spread utilization. There is a growing body of evidence supporting its use at the time of phacoemulsification to help lower IOP. However, it is still not clear how much of the IOP lowering effect can be attributed to the iStent, the crystalline lens extraction or both when inserted concurrently at the time of phacoemulsification. This has been an important issue in understanding its potential role in the glaucoma management paradigm. Purpose To conduct a systematic review and meta-analysis comparing the IOP lowering effect of iStent insertion at the time of phacoemulsification versus phacoemulsification alone for patients with glaucoma and cataracts. Methods A systematic review was conducted utilizing various databases. Studies examining the IOP lowering effect of iStent insertion in combination with phacoemulsification, as well as studies examining the IOP lowering effect of phacoemulsification alone were included. Thirty-seven studies, reporting on 2495 patients, met the inclusion criteria. The percentage reduction in IOP (IOPR%) and mean reduction in topical glaucoma medications after surgery were determined. The standardized mean difference (SMD) was computed as a measure of the treatment effect for continuous outcomes taking into account heterogeneity. Fixed-effect and random-effect models were applied. Results A 4% IOP reduction (IOPR%) from baseline occurred following phacoemulsification as a solo procedure compared to 9% following an iStent implant with phacoemulsification, and 27% following 2 iStents implants with phacoemulsification. Compared with cataract extraction alone, iStent with phacoemulsification resulted in significant reduction in the post-operative IOP (IOPR%) (SMD = -0.46, 95% CI: [-0.87, -0.06]). A weighted mean reduction in the number of glaucoma medications per patient was 1.01 following phacoemulsification alone compared to 1.33 after one iStent implant with phacoemulsification, and 1.1 after 2 iStent implants with phacoemulsification. Compared to cataract extraction alone, iStent with cataract extraction showed a significant decrease in the number of glaucoma medications (SMD = -0.65, 95% CI: [-1.18, -0.12]). Funnel plots suggested the absence of publication bias. Conclusion Both iStent implantation with concurrent phacoemulsification and phacoemulsification alone result in a significant decrease in IOP and topical glaucoma medications. In terms of both reductions, iStent with phacoemulsification significantly outperforms phacoemulsification alone. PMID:26147908

Atheromatous occlusive lesions of the popliteal artery treated with stent grafts: predictive factors of midterm patency.

PubMed

Peidro, Jérémie; Boufi, Mourad; Loundou Dieudonné, Anderson; Hartung, Olivier; Dona, Bianca; Vernet, Florent; Alimi, Yves

2015-01-01

Because of its location, the popliteal artery is exposed to important biomechanical constraints, inducing a specific risk of thrombosis of stents, little studied in the literature. The objective of this monocentric retrospective study was to evaluate the patency of stents implanted in the popliteal artery to treat atheromatous lesions and the risk factors predisposing to thrombosis. Between January 2009 and July 2013, all the patients receiving stents for a residual stenosis or a complication of angioplasty in the popliteal artery or the distal anastomosis of a femoropopliteal bypass were included retrospectively and in an intention to treat. Forty-six patients (17 women), with a 71.5 years median age (range, 45-90 years), including 17 diabetic patients (37%) and 7 hemodialysis patients (15%), were operated in 51 limbs for claudication (n = 25, 49%), critical ischemia (n = 18, 35%), or acute ischemia (n = 8, 16%). Thirty stenoses >70% (59%) and 21 thromboses (41%) were treated with 56 autoexpandable stents, with an average diameter of 6 mm (range, 5-8 mm) and an average length of 5 cm (range, 4-15 cm), including 39 lesions in P1 (above the patella), 8 in P2 (articular), and 4 in P3 (distal popliteal artery). The following factors were analyzed according to univariate and multivariate models: age, gender, Society for Vascular Surgery score, symptomatology, type and location of lesion, number of stents deployed, and dimension of stents. Technical success was of 98% (n = 50), including 1 insufficient result of the endovascular treatment. At 30 days, one patient treated for critical ischemia died (2%) and one residual popliteal stenosis was treated by bypass (2%). After a 27.6 ± 10.07 month follow-up, restenosis (>50%) was detected in 5 cases including 4 asymptomatic and a popliteal thrombosis occurred in 9 cases, including 3 asymptomatic cases. Eight secondary interventions were necessary, including 4 endovascular procedures, 3 bypasses, and only 1 major amputation (thigh). The primary and secondary patencies at 12 months and 24 months were 80% and 65%, and 90% and 74%, respectively. The multivariate analysis showed that the type of lesion (stenosis versus occlusion; odds ratio [OR], 5.1; 95% confidence interval [CI], 1.2-22.9, P = 0.032) and the number of stents implanted (1 vs. 2 stents; OR [95% CI], 12.7 [1.8-88.5]; P = 0.011) were independent predictive factors of secondary thrombosis. The endovascular treatment of the atheromatous popliteal lesions appears to be a satisfactory alternative. The implantation of 1 stent in the popliteal artery is recommended in the event of popliteal occlusion, whereas for a stenosis, it must be reserved for patients with residual stenosis or in the event of complications of angioplasty, such as dissection or elastic recoil. Stent must be single, with deployment of a long stent in the event of long lesion. Copyright © 2015 Elsevier Inc. All rights reserved.

Percutaneous pulmonary valve implantation for free pulmonary regurgitation following conduit-free surgery of the right ventricular outflow tract.

PubMed

Cools, Bjorn; Brown, Stephen C; Heying, Ruth; Jansen, Katrijn; Boshoff, Derize E; Budts, Werner; Gewillig, Marc

2015-01-01

Pulmonary regurgitation (PR) following surgery of the right ventricular outflow tract (RVOT) is not innocent and leads to significant right heart dysfunction over time. Recent studies have demonstrated that percutaneous valves can be implanted in conduit free outflow tracts with good outcomes. To evaluate in patients with severe PR--anticipated to require future pulmonary valve replacement--the feasibility and safety of pre-stenting dilated non-stenotic patched conduit-free right ventricular outflow tracts before excessive dilation occurs, followed by percutaneous pulmonary valve implantation (PPVI). Twenty seven patients were evaluated, but only 23 were deemed suitable based on the presence of an adequate retention zone ≤ 24 mm defined by semi-compliant balloon interrogation of the RVOT. A 2 step procedure was performed: first the landing zone was prepared by deploying a bare stent, followed 2 months later by valve implantation. RVOT pre-stenting with an open cell bare metal stent (Andrastent XXL range) was performed at a median age of 13.0 years (range: 6.0-44.9) with a median weight of 44.3 kg (range: 20.0-88.0). Ninety six percent (22/23) of patients proceeded to PPVI a median of 2.4 months (range: 1.4-3.4) after initial pre-stent placement. Twenty one Melody valves and one 26 mm Edwards SAPIEN™ valve were implanted. Complications consisted of embolization of prestent (n = 1), scrunching (n = 4) and mild stent dislocation (n = 2). During follow-up, no stent fractures were observed and right ventricular dimensions decreased significantly. Post-surgical conduit-free non-stenotic RVOT with free pulmonary regurgitation can be treated percutaneously with a valved stent if anatomical (predominantly size) criteria are met. In experienced hands, the technique is feasible with low morbidity. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Portal Vein Stenting Combined with Iodine-125 Seeds Endovascular Implantation Followed by Transcatheter Arterial Chemoembolization for Treatment of Hepatocellular Carcinoma Patients with Portal Vein Tumor Thrombus

PubMed Central

Zhou, Tanyang; Zhu, Tongyin; Zhang, Yuelin; Nie, Chunhui; Ai, Jing; Zhou, Guanhui; Zhang, Aibin; Dong, Meng-Jie; Wang, Wei-Lin

2016-01-01

Aim was to assess the therapeutic value of portal vein stenting (PVS) combined with iodine-125 seed (125I seed) strand endovascular implantation followed by transcatheter arterial chemoembolization (TACE) for treating patients with hepatocellular carcinoma (HCC) and portal vein tumor thrombus (PVTT). This was a retrospective study of 34 patients aged 29–81 years, diagnosed HCC with PVTT, and treated with PVS combined with 125I seed strand endovascular implantation followed by TACE between January 2012 and August 2014. Survival, stent patency, technical success rate, complications related to the procedure, and adverse events were recorded. The technical success rate was 100%. No serious procedure-related adverse event was recorded. The median survival was 147 days. The cumulative survival rates and stent patency rates at 90, 180, and 360 days were 94.1%, 61.8%, and 32.4% and 97.1% (33/34), 76.9% (24/34), and 29.4% (10/34), respectively. PVS combined with 125I seed strand endovascular implantation followed by TACE is feasible for patients with HCC and PVTT. It resulted in appropriate survival and stent patency, with no procedure-related adverse effects. PMID:27999793

Late Pseudocoarctation Syndrome After Stent-Graft Implantation For Traumatic Aortic Rupture

DOE Office of Scientific and Technical Information (OSTI.GOV)

Letocart, Vincent, E-mail: vincent.letocart@chu-nantes.fr; Fau, Georges, E-mail: georges.fau@chu-nantes.fr; Tirouvanziam, Ashok, E-mail: ashok.tirouvanziam@chu-nantes.fr

The present observation illustrates an unusual complication occurring after stent-grafting (S-graft) for aortic isthmus rupture. A 22-year-old patient, treated by S-graft in the emergency department for traumatic aortic rupture, was readmitted 10 months later with pseudocoarctation syndrome. A membrane was found inside the stent-graft that had induced a pseudo-dissection, which caused the pseudocoarctation syndrome. Surgical treatment consisted of removing the stent-graft and membrane and replacing it with a vascular implant. The patient's clinical course was fair. The suggested mechanism was circumferential neoendothelialization of the stent-graft. Dehiscence caused the superior part of the membrane to drop into the lumen of themore » stent-graft creating a 'false channel' that compressed the 'true lumen' and induced 'pseudocoarctation' syndrome. The cause of the extensive neointimalization remains unexplained. Thoracic aortic stent-grafts require regular follow-up monitoring by angioscan or angio-magnetic resonance imaging.« less

Computer Simulation of the Mechanical Behaviour of Implanted Biodegradable Stents in a Remodelling Artery

NASA Astrophysics Data System (ADS)

Boland, Enda L.; Grogan, James A.; Conway, Claire; McHugh, Peter E.

2016-04-01

Coronary stents have revolutionised the treatment of coronary artery disease. While coronary artery stenting is now relatively mature, significant scientific and technological challenges still remain. One of the most fertile technological growth areas is biodegradable stents; here, there is the possibility to generate stents that will break down in the body once the initial necessary scaffolding period is past (6-12 months) (Grogan et al. in Acta Biomater 7:3523, 2011) and when the artery has remodelled (including the formation of neo-intima). A stent angioplasty computational test-bed has been developed by the authors, based on the Abaqus software (DS-SIMULIA, USA), capable of simulating stent tracking, balloon expansion, recoil and in vivo loading in a atherosclerotic artery model. Additionally, a surface corrosion model to simulate uniform and pitting corrosion of biodegradable stents and a representation of the active response of the arterial tissue following stent implantation, i.e. neointimal remodelling, has been developed. The arterial neointimal remodelling simulations with biodegradable stent corrosion demonstrate that the development of new arterial tissue around the stent struts has a substantial effect on the mechanical behaviour of degrading stents.

Flat panel digital detector cinefluoroscopy late following SES or BMS implantation for detection of coronary stent fracture in asymptomatic patients.

PubMed

Davlouros, Periklis A; Chefneux, Corina; Xanthopoulou, Ioanna; Papathanasiou, Maria; Zaharioglou, Evaggelia; Tsigkas, Grigorios; Alexopoulos, Dimitrios

2012-05-03

Coronary stent fracture (SF), is rare and confined mainly in patients treated with sirolimus eluting stents (SES). The role of flat panel digital detector (FPDD) fluoroscopy in detecting SF has not been investigated. Assessment with FPDD fluoroscopy of asymptomatic patients, with 200 SES (Cypher, Cordis, J&J, Miami, Florida, US), and 200 bare metal stents (BMS), at 45.5 ± 15.7 and 38.4 ± 3.9 months post-stenting respectively. SF was defined as discontinuity of stent struts on fluoroscopy. Coronary angiography was reserved for patients with documented SF. Effective radiation dose was 0.26 ± 0.14 mSv. SF was depicted in 6 (3%) SES, and 1 BMS (0.5%). Stent length was an independent predictor of SF (OR 1.19, 95% CI 1.03-1.4, p=0.024). RCA location and vessel angulation were marginally significant (OR 7.7, 95% CI 0.8-74.2, p=0.077 and OR 5.1, 95% CI 0.8-34, p=0.089). Significant angiographic restenosis was detected in 4 SES (66.6%), and 1 BMS (0.5%). Re-intervention was needed in 3 (42.8%) cases, (2 SES and 1 BMS). Detection of SF with FPDD cinefluoroscopy late following coronary stenting is feasible, involves low radiation and is confined mainly to SES compared to BMS. Application of cinefluoroscopy as part of a routine stent surveillance programme in asymptomatic patients may be more appropriate in "high risk" settings (SES, long stents and adverse angiographic characteristics). The role of invasive imaging and subsequent management of such patients need further studying. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

Comparison of Long-Term Clinical Outcomes of Lesions Exhibiting Focal and Segmental Peri-Stent Contrast Staining.

PubMed

Tokuda, Takahiro; Yamawaki, Masahiro; Takahara, Mitsuyohi; Mori, Shinsuke; Makino, Kenji; Honda, Yosuke; Takafuji, Hiroya; Takama, Takuro; Tsutsumi, Masakazu; Sakamoto, Yasunari; Takimura, Hideyuki; Kobayashi, Norihiro; Araki, Motoharu; Hirano, Keisuke; Ito, Yoshiaki

2016-03-18

Peri-stent contrast staining (PSS) after metallic drug-eluting stent deployment is associated with target lesion revascularization and very late stent thrombosis. However, the type of PSS that influences the clinical outcomes is unknown. Therefore, we aimed to reveal which PSS type was influencing clinical outcomes. This study included 5580 de novo lesions of 4405 patients who were implanted with a first- or second-generation drug-eluting stent and who were evaluated using follow-up angiography within 12 months after stent implantation. We compared the clinical outcomes of patients divided into focal PSS and segmental PSS groups for 6 years after stent implantation. Total PSS was observed in 97 lesions (2.2%), of which 42 and 55 lesions were focal and segmental PSS, respectively. Baseline characteristics were similar between groups, except for intraoperative chronic total occlusion (segmental PSS=47.3% versus focal PSS=11.9%, P=0.0001). The incidence of segmental PSS tended to be higher in patients with a first-generation drug-eluting stent (83.6% versus 16.4%, P=0.05). The cumulative incidence of stent thrombosis in the 6 years of segmental PSS group was significantly higher than that of the focal PSS group (13.9% versus 0%, P=0.04). The cumulative incidence of overall target lesion revascularization for restenosis, excluding target lesion revascularization procedures for stent thrombosis, was significantly higher in the segmental PSS group (38.0% versus 0%, P=0.01). The incidence of segmental PSS tended to be higher in patients with a first-generation drug-eluting stent and appeared to be significantly associated with target lesion revascularization and stent thrombosis. © 2016 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

Modifying effect of dual antiplatelet therapy on incidence of stent thrombosis according to implanted drug-eluting stent type.

PubMed

Camenzind, Edoardo; Boersma, Eric; Wijns, William; Mauri, Laura; Rademaker-Havinga, Tessa; Ordoubadi, Farzin Fath; Suttorp, Maarten J; Al Kurdi, Mohammad; Steg, Ph Gabriel

2014-08-01

To investigate the putative modifying effect of dual antiplatelet therapy (DAPT) use on the incidence of stent thrombosis at 3 years in patients randomized to Endeavor zotarolimus-eluting stent (E-ZES) or Cypher sirolimus-eluting stent (C-SES). Of 8709 patients in PROTECT, 4357 were randomized to E-ZES and 4352 to C-SES. Aspirin was to be given indefinitely, and clopidogrel/ticlopidine for ≥ 3 months or up to 12 months after implantation. Main outcome measures were definite or probable stent thrombosis at 3 years. Multivariable Cox regression analysis was applied, with stent type, DAPT, and their interaction as the main outcome determinants. Dual antiplatelet therapy adherence remained the same in the E-ZES and C-SES groups (79.6% at 1 year, 32.8% at 2 years, and 21.6% at 3 years). We observed a statistically significant (P = 0.0052) heterogeneity in treatment effect of stent type in relation to DAPT. In the absence of DAPT, stent thrombosis was lower with E-ZES vs. C-SES (adjusted hazard ratio 0.38, 95% confidence interval 0.19, 0.75; P = 0.0056). In the presence of DAPT, no difference was found (1.18; 0.79, 1.77; P = 0.43). A strong interaction was observed between drug-eluting stent type and DAPT use, most likely prompted by the vascular healing response induced by the implanted DES system. These results suggest that the incidence of stent thrombosis in DES trials should not be evaluated independently of DAPT use, and the optimal duration of DAPT will likely depend upon stent type (Clinicaltrials.gov number NCT00476957). Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2014. For permissions please email: journals.permissions@oup.com.

A new self-expandable aortic valved stent deployed above native leaflets for aortic insufficiency: an in vitro study.

PubMed

Huang, H; Zhou, Y; Shao, J; Cai, J; Mei, Y; Wang, Y

2012-12-01

The aim of this paper was to develop a new self-expandable aortic valved stent following the shape of the sinus of Valsalva, which can be deployed above native leaflets for aortic regurgitation, and study it's effect on coronary artery flow when orthotopic implantation in and above native leaflets. New self-expandable aortic valved stent consist of nitinol stent and bovine pericardium, and was designed following the shape of the sinus of Valsalva, the bovine pericardium was tailed as native leaflet. Thirty-six swine hearts were divided into three equal groups of twelve. In Group A (N.=12), the new self-expandable aortic valved stents deployed in native leaflets. In Group B (N.=12), the new self-expandable aortic valved stents deployed above native leaflets. In Group C (N.=12), the cylinder-like valved stents deployed only in native leaflets. The measurements of each coronary flow rate and endoscopic inspections were repeated post-implantation. In Group A and C, valve implantation in native leaflets resulted in a significant decrease in both left and right coronary flows. In Group B, no significant change in either right or left coronary flow was found after new self-expandable aortic valved stent placement. Endoscopic inspections showed that in group A and C the native leaflets sandwiched between valved stent and aortic wall, whereas, in group B the native leaflets were under the artificial leaflets. Two kinds of stents deployed in native leaflets affect left and right coronary flows significantly. No significant effect was found when the new self-expandable aortic valved stent deployed above native leaflets. This new self-expandable aortic valved stent can be deployed above the native leaflets, which avoids the obstruction of native leaflets on coronary flow.

Intelligent telemetric stent for wireless monitoring of intravascular pressure and its in vivo testing.

PubMed

Chen, Xing; Brox, Daniel; Assadsangabi, Babak; Hsiang, York; Takahata, Kenichi

2014-10-01

This paper reports a sensor-integrated telemetric stent targeted at wireless detection and monitoring of restenosis, a common vascular complication induced by stent implantation. The developed "smart" stent incorporates the design and fabrication approaches that raise the practicality of the device, being tested in an in vivo study that validates its operating principle. The stent is produced to have a gold-coated helical-like structure that serves as a high-performance inductor/antenna and integrated with a novel capacitive pressure sensor chip, all based on medical-grade stainless steel. The stent device forms an inductor-capacitor resonant tank that enables radio-frequency (RF) wireless pressure sensing in an operating frequency range of 30-80 MHz. With an overall length of 20 mm, the device is designed to be compatible with standard balloon catheters and necessary crimping process. The balloon-expanded devices are characterized in saline and blood to determine selective coating of passivation layer, Parylene C, with tailored thicknesses in order to maximize both RF and sensing abilities. In vitro testing of the devices reveals a frequency sensitivity up to 146 ppm/mmHg over a pressure range of 250 mmHg. Tests in pig models show wireless detection of device's resonance and frequency response to variations in local blood pressure, the targeted function of the device.

Prevalence, Features, and Prognostic Importance of Edge Dissection After Drug-Eluting Stent Implantation: An ADAPT-DES Intravascular Ultrasound Substudy.

PubMed

Kobayashi, Nobuaki; Mintz, Gary S; Witzenbichler, Bernhard; Metzger, D Christopher; Rinaldi, Michael J; Duffy, Peter L; Weisz, Giora; Stuckey, Thomas D; Brodie, Bruce R; Parvataneni, Rupa; Kirtane, Ajay J; Stone, Gregg W; Maehara, Akiko

2016-07-01

Intravascular ultrasound detects stent edge dissections after percutaneous coronary intervention that are not seen angiographically. This study investigated the association between stent edge dissections and clinical outcomes. ADAPT-DES (Assessment of Dual Antiplatelet Therapy With Drug-Eluting Stents) was a large-scale, prospective, multicenter study of patients undergoing drug-eluting stent implantation. In this prospective substudy, 2062 patients (2433 lesions) were evaluated with intravascular ultrasound to characterize the morphological features and clinical outcomes of stent edge dissection after percutaneous coronary intervention. The prevalence of post-percutaneous coronary intervention stent edge dissection was 6.6% per lesion (161 of 2433). Calcified plaque at the proximal stent edge (relative risk [RR]=1.72; P=0.04) and proximal stent edge expansion (RR=1.18; P=0.004) were predictors for proximal dissection; attenuated plaque at the distal stent edge (RR=3.52; P=0.004), distal reference plaque burden (RR=1.56; P<0.0001), and distal edge stent expansion (RR=1.11; P=0.02) were predictors for distal dissection. At 1-year follow-up, target lesion revascularization was more common in lesions with versus without dissection (5.2% versus 2.7%; P=0.04). Multivariable analysis indicated that residual dissection was associated with target lesion revascularization at 1-year follow-up (RR=2.67; P=0.02). Among lesions with dissection, smaller effective lumen area increased the risk of target lesion revascularization at 1-year follow-up (cutoff value of 5.1 mm(2); P=0.05). Greater stent expansion and the presence of large, calcified, and/or attenuated plaques were independent predictors of stent edge dissection. Residual stent edge dissection, especially with a smaller effective lumen area, was associated with target lesion revascularization during 1-year follow-up after drug-eluting stent implantation. URL: http://www.clinicaltrials.gov. Unique identifier: NCT00638794. © 2016 American Heart Association, Inc.

A review of the in vivo and in vitro biomechanical behavior and performance of postoperative abdominal aortic aneurysms and implanted stent-grafts.

PubMed

Corbett, Timothy J; Callanan, Anthony; Morris, Liam G; Doyle, Barry J; Grace, Pierce A; Kavanagh, Eamon G; McGloughlin, Tim M

2008-08-01

Endovascular repair of abdominal aortic aneurysms has generated widespread interest since the procedure was first introduced two decades ago. It is frequently performed in patients who suffer from substantial comorbidities that may render them unsuitable for traditional open surgical repair. Although this minimally invasive technique substantially reduces operative risk, recovery time, and anesthesia usage in these patients, the endovascular method has been prone to a number of failure mechanisms not encountered with the open surgical method. Based on long-term results of second- and third-generation devices that are currently becoming available, this study sought to identify the most serious failure mechanisms, which may have a starting point in the morphological changes in the aneurysm and stent-graft. To investigate the "behavior" of the aneurysm after stent-graft repair, i.e., how its length, angulation, and diameter change, we utilized state-of-the-art ex vivo methods, which researchers worldwide are now using to recreate these failure modes.

Risk factors for proximal migration of biliary tube stents

PubMed Central

Kawaguchi, Yoshiaki; Ogawa, Masami; Kawashima, Yohei; Mizukami, Hajime; Maruno, Atsuko; Ito, Hiroyuki; Mine, Tetsuya

2014-01-01

AIM: To analyze the risk factors for biliary stent migration in patients with benign and malignant strictures. METHODS: Endoscopic stent placement was performed in 396 patients with bile duct stenosis, at our institution, between June 2003 and March 2009. The indications for bile duct stent implantation included common bile duct stone in 190 patients, malignant lesions in 112, chronic pancreatitis in 62, autoimmune pancreatitis in 14, trauma in eight, surgical complications in six, and primary sclerosing cholangitis (PSC) in four. We retrospectively examined the frequency of stent migration, and analyzed the patient factors (disease, whether endoscopic sphincterotomy was performed, location of bile duct stenosis and diameter of the bile duct) and stent characteristics (duration of stent placement, stent type, diameter and length). Moreover, we investigated retrieval methods for migrated stents and their associated success rates. RESULTS: The frequency of tube stent migration in the total patient population was 3.5%. The cases in which tube stent migration occurred included those with common bile duct stones (3/190; 1.6%), malignant lesions (2/112; 1.8%), chronic pancreatitis (4/62; 6.5%), autoimmune pancreatitis (2/14; 14.3%), trauma (1/8; 12.5%), surgical complications (2/6; 33.3%), and PSC (0/4; 0%). The potential risk factors for migration included bile duct stenosis secondary to benign disease such as chronic pancreatitis and autoimmune pancreatitis (P = 0.030); stenosis of the lower bile duct (P = 0.031); bile duct diameter > 10 mm (P = 0.023); duration of stent placement > 1 mo (P = 0.007); use of straight-type stents (P < 0.001); and 10-Fr sized stents (P < 0.001). Retrieval of the migrated stents was successful in all cases. The grasping technique, using a basket or snare, was effective for pig-tailed or thin and straight stents, whereas the guidewire cannulation technique was effective for thick and straight stents. CONCLUSION: Migration of tube stents within the bile duct is rare but possible, and it is important to determine the risk factors involved in stent migration. PMID:24574806

Drug eluting stents and modern stent technologies for in-stent restenosis.

PubMed

Werner, Martin

2017-08-01

The implantation of metallic stents has become a standard procedure to improve the outcome after angioplasty of peripheral vessels. However, the occurrence of in-stent restenosis is hampering the long-term efficacy of these procedures and is associated with re-occurrence of symptoms. The optimal treatment modality for in-stent-restenosis in the peripheral vasculature is not well examined. This review discusses the existing evidence for the treatment of in-stent restenosis with drug eluting stents and modern stent technologies.

In-situ investigation of stress conditions during expansion of bare metal stents and PLLA-coated stents using the XRD sin(2)ψ-technique.

PubMed

Kowalski, Wolfgang; Dammer, Markus; Bakczewitz, Frank; Schmitz, Klaus-Peter; Grabow, Niels; Kessler, Olaf

2015-09-01

Drug eluting stents (DES) consist of platform, coating and drug. The platform often is a balloon-expandable bare metal stent made of the CoCr alloy L-605 or stainless steel 316 L. The function of the coating, typically a permanent polymer, is to hold and release the drug, which should improve therapeutic outcome. Before implantation, DES are compressed (crimped) to allow implantation in the human body. During implantation, DES are expanded by balloon inflation. Crimping, as well as expansion, causes high stresses and high strains locally in the DES struts, as well as in the polymer coating. These stresses and strains are important design criteria of DES. Usually, they are calculated numerically by finite element analysis (FEA), but experimental results for validation are hardly available. In this work, the X-ray diffraction (XRD) sin(2)ψ-technique is applied to in-situ determination of stress conditions of bare metal L-605 stents, and Poly-(L-lactide) (PLLA) coated stents. This provides a realistic characterization of the near-surface stress state and a validation option of the numerical FEA. XRD-results from terminal stent struts of the bare metal stent show an increasing compressive load stress in tangential direction with increasing stent expansion. These findings correlate with numerical FEA results. The PLLA-coating also bears increasing compressive load stress during expansion. Copyright © 2015 Elsevier Ltd. All rights reserved.

Comparison of diamond-like carbon-coated nitinol stents with or without polyethylene glycol grafting and uncoated nitinol stents in a canine iliac artery model

PubMed Central

Kim, J H; Shin, J H; Shin, D H; Moon, M-W; Park, K; Kim, T-H; Shin, K M; Won, Y H; Han, D K; Lee, K-R

2011-01-01

Objective Neointimal hyperplasia is a major complication of endovascular stent placement with consequent in-stent restenosis or occlusion. Improvements in the biocompatibility of stent designs could reduce stent-associated thrombosis and in-stent restenosis. We hypothesised that the use of a diamond-like carbon (DLC)-coated nitinol stent or a polyethylene glycol (PEG)-DLC-coated nitinol stent could reduce the formation of neointimal hyperplasia, thereby improving stent patency with improved biocompatibility. Methods A total of 24 stents were implanted, under general anaesthesia, into the iliac arteries of six dogs (four stents in each dog) using the carotid artery approach. The experimental study dogs were divided into three groups: the uncoated nitinol stent group (n = 8), the DLC-nitinol stent group (n = 8) and the PEG-DLC-nitinol stent group (n = 8). Results The mean percentage of neointimal hyperplasia was significantly less in the DLC-nitinol stent group (26.7±7.6%) than in the nitinol stent group (40.0±20.3%) (p = 0.021). However, the mean percentage of neointimal hyperplasia was significantly greater in the PEG-DLC-nitinol stent group (58.7±24.7%) than in the nitinol stent group (40.0±20.3%) (p = 0.01). Conclusion Our findings indicate that DLC-coated nitinol stents might induce less neointimal hyperplasia than conventional nitinol stents following implantation in a canine iliac artery model; however, the DLC-coated nitinol stent surface when reformed with PEG induces more neointimal hyperplasia than either a conventional or DLC-coated nitinol stent. PMID:21325363

Biodegradable biliary stent implantation in the treatment of benign bilioplastic-refractory biliary strictures: preliminary experience.

PubMed

Mauri, Giovanni; Michelozzi, Caterina; Melchiorre, Fabio; Poretti, Dario; Tramarin, Marco; Pedicini, Vittorio; Solbiati, Luigi; Cornalba, Gianpaolo; Sconfienza, Luca Maria

2013-12-01

To evaluate feasibility, safety, and outcome of patients treated with biodegradable biliary stents for benign biliary stenosis refractory to other treatments. Between March 2011 and September 2012, ten patients (seven men, three women; age 59 ± 7 years) with recurrent cholangitis due to postsurgical biliary stricture, previous multiple unsuccessful (two to five) bilioplasties, and unsuitability for surgical/endoscopic repair underwent percutaneous implantation of a biodegradable biliary stent. Patients were followed-up clinically and with ultrasound at 1, 3 and 6 months, and then at 6-month intervals. Stent implantation was always feasible. No immediate major or minor complications occurred. In all patients, 48-h cholangiographic control demonstrated optimal stent positioning and stenosis resolution. In a median follow-up time of 16.5 months (25th-75th percentiles = 11-20.25 months) no further invasive treatment was needed. Three patients experienced transient episodes of cholangitis. Neither re-stenosis nor dilatation of the biliary tree was documented during follow-up. No stent was visible at the 6-month follow-up. Percutaneous placement of biodegradable biliary stents represents a new option in treating benign biliary stenoses refractory to treatment with bilioplasty. This technique seems to be feasible, effective and free from major complications. Further investigations are warranted to confirm our preliminary results.

Assessment of a Polyester-Covered Nitinol Stent in the Canine Aorta and Iliac Arteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Castaneda, Flavio; Ball-Kell, Susan M.; Young, Kate

Purpose: To evaluate the patency and healing characteristics of a woven polyester fabric-covered stent in the canine model.Methods: Twenty-four self-expanding covered stents were placed in the infrarenal aorta and bilateral common iliac arteries of eight dogs and evaluated at 1 (n = 2), 3 (n = 2), and 6 (n = 4) months. Stent assessment was done using angiography prior to euthanasia, and light and scanning electron microscopy.Results: Angiographically, just prior to euthanasia, 8 of 8 aortic and 14 of 16 iliac endovascular covered stents were patent. Histologically, the stented regions showed complete endothelialization 6 months after graft implantation. Amore » neointima had formed inside the stented vessel regions resulting in complete encasement of the fabric-covered stent by 3 months after graft implantation. Medial compression with smooth muscle cell atrophy was present in all stented regions. Explanted stent wires, examined by scanning electron microscopy, showed pitting but no cracks or breakage.Conclusion: The covered stent demonstrated predictable healing and is effective in preventing stenosis in vessels 10.0 mm or greater in diameter but does not completely preclude stenosis in vessels 6.0 mm or less in diameter.« less

Bio-Adaption between Magnesium Alloy Stent and the Blood Vessel: A Review.

PubMed

Ma, Jun; Zhao, Nan; Betts, Lexxus; Zhu, Donghui

2016-09-01

Biodegradable magnesium (Mg) alloy stents are the most promising next generation of bio-absorbable stents. In this article, we summarized the progresses on the in vitro studies, animal testing and clinical trials of biodegradable Mg alloy stents in the past decades. These exciting findings led us to propose the importance of the concept "bio-adaption" between the Mg alloy stent and the local tissue microenvironment after implantation. The healing responses of stented blood vessel can be generally described in three overlapping phases: inflammation, granulation and remodeling. The ideal bio-adaption of the Mg alloy stent, once implanted into the blood vessel, needs to be a reasonable function of the time and the space/dimension. First, a very slow degeneration of mechanical support is expected in the initial four months in order to provide sufficient mechanical support to the injured vessels. Although it is still arguable whether full mechanical support in stented lesions is mandatory during the first four months after implantation, it would certainly be a safety design parameter and a benchmark for regulatory evaluations based on the fact that there is insufficient human in vivo data available, especially the vessel wall mechanical properties during the healing/remodeling phase. Second, once the Mg alloy stent being degraded, the void space will be filled by the regenerated blood vessel tissues. The degradation of the Mg alloy stent should be 100% completed with no residues, and the degradation products (e.g., ions and hydrogen) will be helpful for the tissue reconstruction of the blood vessel. Toward this target, some future research perspectives are also discussed.

Bio-Adaption between Magnesium Alloy Stent and the Blood Vessel: A Review

PubMed Central

Ma, Jun; Zhao, Nan; Betts, Lexxus; Zhu, Donghui

2016-01-01

Biodegradable magnesium (Mg) alloy stents are the most promising next generation of bio-absorbable stents. In this article, we summarized the progresses on the in vitro studies, animal testing and clinical trials of biodegradable Mg alloy stents in the past decades. These exciting findings led us to propose the importance of the concept “bio-adaption” between the Mg alloy stent and the local tissue microenvironment after implantation. The healing responses of stented blood vessel can be generally described in three overlapping phases: inflammation, granulation and remodeling. The ideal bio-adaption of the Mg alloy stent, once implanted into the blood vessel, needs to be a reasonable function of the time and the space/dimension. First, a very slow degeneration of mechanical support is expected in the initial four months in order to provide sufficient mechanical support to the injured vessels. Although it is still arguable whether full mechanical support in stented lesions is mandatory during the first four months after implantation, it would certainly be a safety design parameter and a benchmark for regulatory evaluations based on the fact that there is insufficient human in vivo data available, especially the vessel wall mechanical properties during the healing/remodeling phase. Second, once the Mg alloy stent being degraded, the void space will be filled by the regenerated blood vessel tissues. The degradation of the Mg alloy stent should be 100% completed with no residues, and the degradation products (e.g., ions and hydrogen) will be helpful for the tissue reconstruction of the blood vessel. Toward this target, some future research perspectives are also discussed. PMID:27698548

Temporal course of vascular healing and neoatherosclerosis after implantation of durable- or biodegradable-polymer drug-eluting stents.

PubMed

Guagliumi, Giulio; Shimamura, Kunihiro; Sirbu, Vasile; Garbo, Roberto; Boccuzzi, Giacomo; Vassileva, Angelina; Valsecchi, Orazio; Fiocca, Luigi; Canova, Paolo; Colombo, Francesco; Tensol Rodriguez Pereira, Gabriel; Nakamura, Daisuke; Attizzani, Guilherme F; Cereda, Alberto; Satogami, Keisuke; De Luca, Leonardo; Saia, Francesco; Capodanno, Davide

2018-05-19

Delayed healing and endothelial dysfunction may occur with drug-eluting stents (DES), promoting accelerated infiltration of lipids in the neointima and development of neoatherosclerosis (NA). Pathology data suggest durable polymer (DP) of DES to play a major role in this process. Whether biodegradable polymer (BP) may address these issues is uncertain. We compared in vivo vessel healing and NA of current generation BP- or DP-DES using serial optical coherence tomography (OCT) assessments. Ninety patients with multivessel coronary artery disease were randomized 1:1 to BP everolimus-eluting stents (EES, Synergy) or DP zotarolimus-eluting stents (ZES, Resolute Integrity). Co-primary endpoints were the maximum length of uncovered struts at 3 months (powered for non-inferiority) and the percentage of patients presenting with frames of NA at 18 months (powered for superiority) as measured by OCT. The maximum length of uncovered struts at 3 months was 10 ± 8 mm in the BP-EES group and 11 ± 7 mm in the DP-ZES group (mean difference -1 mm; upper 97.5% confidence interval +2 mm; P = 0.05 for non-inferiority; P = 0.45 for superiority). The percentage of patients presenting with frames of NA at 18 months was low and similar between BP-EES and DP-ZES groups (11.6% vs. 15.9%; P = 0.56). There was no stent thrombosis in both groups at 24 months. BP-EES and DP-ZES showed a similar healing response at 3 months and a low incidence of NA at 18 months. Biocompatible polymers, regardless of whether they are durable or biodegradable, may favourably impact the long-term vascular response to current-generation DES.

Effect of specific surface microstructures on substrate endothelialisation and thrombogenicity: Importance for stent design.

PubMed

Lutter, Christoph; Nothhaft, Matthias; Rzany, Alexander; Garlichs, Christoph D; Cicha, Iwona

2015-01-01

In coronary artery disease, highly stenosed arteries are frequently treated by stent implantation, which thereafter necessitates a dual-antiplatelet therapy (DAPT) in order to prevent stent-thrombosis. We hypothesized that specific patterns of microstructures on stents can accelerate endothelialisation thereby reducing their thrombogenicity and the DAPT duration. Differently designed, 2-5 μm high elevations or hollows were lithographically etched on silicon plates, subsequently coated with silicon carbide. Smooth silicon plates and bare metal substrates were used as controls. To assess attachment and growth of human umbilical vein endothelial cells under static or flow conditions, actin cytoskeleton was visualised with green phalloidin. Endothelial migration was assessed in a modified barrier assay. To investigate surface thrombogenicity, platelets were incubated on the structured surfaces in static and flow conditions, and visualised with fluorescein-conjugated P-selectin antibody. Images were taken with incident-light fluorescent microscope for non-transparent objects. Compared to smooth surface, flat cubic elevations (5 μm edge length) improved endothelial cell attachment and growth under static and dynamic conditions, whereas smaller, spiky structures (2 μm edge length) had a negative influence on endothelialisation. Endothelial cell migration was fastest on flat cubic elevations, hollows, and smooth surfaces, whereas spiky structures and bare metal had a negative effect on endothelial migration. Thrombogenicity assays under static and flow conditions showed that platelet adhesion was reduced on the flat elevations and the smooth surface, as compared to the spiky structures, the hollow design and the bare metal substrates. Surface microstructures strongly influence endothelialisation of substrates. Designing stents with surface topography which accelerates endothelialisation and reduces thrombogenicity may be of clinical benefit by improving the safety profile of coronary interventions.

Noninvasive inductive stent heating: alternative approach to prevent instent restenosis?

PubMed

Floren, Michael G; Günther, Rolf W; Schmitz-Rode, Thomas

2004-05-01

To test noninvasive inductive heating of implanted vascular stents as an alternative approach for reduction or prevention of neointimal hyperplasia. Calorimetric pretests were performed to get an orientation on the different parameters of influence for inductive heating of stents. The field strength was set to a maximum of 90 kA/m within a frequency range from 80 kHz to 320 kHz. The electromagnetic field was emitted by a custom-made water-cooled copper winding antenna. A flow model for stent heating was set up to assess the increase in temperature of an expanded 316L stainless steel stent with typical coronary stent dimensions of 3.5 mm diameter and 14.5 mm in length, and in a second setup with 4.5 mm diameter and 13 mm in length, respectively. The stent was located in a bioartificial artery, simulated by a fibrinogen matrix with a defined number of vital cells. The system was exposed to a pulsating perfusion and to an electromagnetic field of 200 kHz over a period of 20 minutes and in a second setup to an electromagnetic field of 300 kHz and increasing intensity up to maximum power-output. Afterward, the artificial vessel was sliced and examined by fluorescence microscopy to evaluate the number and location of damaged cells. The calorimetric tests show an exponential correlation of energy uptake in the stent with an increase in frequency and a constant generator output. At a frequency of 80 kHz, the power uptake accounts for 0.1 W (250 kHz 1.0 W; 320 kHz 1.9 W, respectively). The flow tests confirmed feasibility to elevate the stent temperature from 37 degrees C body temperature to 44 degrees C at 200 kHz within 55 seconds. The temperature increase of the fluid passing the heated vessel region was only marginal (maximum of 0.5 degrees C). Cell necrosis after 20 minutes of treatment was not observed. In a second set-up with 4.5 mm stent diameter, a frequency of 300 kHz and with maximum power output, the stent temperature was increased to 80 degrees C and there was extensive necrosis area around the stent. Treatment time and stent temperature were optimized in further tests. Selective noninvasive energy transfer to coronary stainless steel stents by inductive heating is possible within a wide range of power. By thermal conduction, vital cells close to the stent struts can be affected. The frequency of 200 kHz turned out to be favorable. There is still room for further optimization of energy dosage with regard to material and stent design, to induce controlled cell death. The method has potential to serve as an alternative approach for prevention of instent restenosis.

Comparison of the 9-month intra-stent conditions and 2-year clinical outcomes after Resolute zotarolimus-eluting stent implantation between 3-month and standard dual antiplatelet therapy.

PubMed

Fujimoto, Wataru; Sawada, Takahiro; Toba, Takayoshi; Takahashi, Yu; Miyata, Taishi; Oishi, Shogo; Osue, Tsuyoshi; Onishi, Tetsuari; Takaya, Tomofumi; Shimane, Akira; Taniguchi, Yasuyo; Kawai, Hiroya; Yasaka, Yoshinori

2018-07-01

The use of short-duration dual antiplatelet therapy (DAPT) remains controversial. To investigate efficacy and safety of short-duration DAPT, we performed a detailed comparison of intra-stent conditions by optical coherence tomography (OCT) after second-generation drug-eluting stent implantation with short-term and standard DAPT. Eighty-two consecutive patients with stable angina pectoris who received Resolute zotarolimus-eluting stents (R-ZESs; Medtronic Cardiovascular, Santa Rosa, CA, USA) were enrolled. Patients were assigned to 3-month (3M group: 41 patients) and standard (standard group: 41 patients) DAPT. In the 3M group, clopidogrel was discontinued 3 months after stent implantation. In the standard group, DAPT was maintained until follow-up OCT. At 9 months, neointimal proliferation was significantly larger in the 3M group, but there were no significant between-group differences in the proportion of uncovered and malapposed strut. The prevalence of abnormal intra-stent tissue (AIT) at 9 months was equivalent between groups. A multiple regression analysis revealed malapposition at 9 months as the strongest independent predictor of AIT at 9 months, and the prevalence of AIT was not associated with DAPT duration. Over 2 years, cardiac events were equal between groups; however, major bleeding was higher tendency in the standard group than in the 3M group. This OCT study indicated that reducing DAPT's duration may provide acceptable arterial healing in patients with implanted R-ZESs. Copyright © 2018 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.

Inhibition of plaque neovascularization and intimal hyperplasia by specific targeting vascular endothelial growth factor with bevacizumab-eluting stent: an experimental study.

PubMed

Stefanadis, Christodoulos; Toutouzas, Konstantinos; Stefanadi, Elli; Lazaris, Andreas; Patsouris, Efstratios; Kipshidze, Nicholas

2007-12-01

Neovascularization is associated with destabilization of atheromatic plaques. Increased expression of vascular endothelial growth factor (VEGF) is important in the process of neovascularization. We assessed the effect of bevacizumab, a monoclonal antibody specific for VEGF, on neovascularization. We used 12 New Zealand rabbits under atherogenic diet for 3 weeks. We immersed a phosphorycholine coated stent into a solution of 4 ml bevacizumab according to previous studies. Twelve eluting stents and 12 non-eluting stents were implanted in the middle segment of the rabbit's iliac arteries. Follow-up angiography was performed at 4 weeks and tissues were obtained for histological analysis. The procedure of stent loading with bevacizumab and stent implantation was successful. There was no difference in angiographic measurements before, after implantation and at follow-up between the two groups. mean neointimal thickness (0.09+/-0.02 versus 0.12+/-0.02 mm, p<0.01), and mean neointimal area (1.08+/-0.09 versus 1.20+/-0.12 mm(2), p<0.01) were less in the bevacizumab treated segments. bevacizumab-treated arterial segments demonstrated significantly decreased microvessel density compared with the control group (1.69+/-0.06 CI: 1.65-1.73 versus 15.68+/-0.56 CI: 15.32-16.04 vessels per mm(2), p<0.001) and vegf expression was decreased in the media and adventitia of bevacizumab group. Endothelialization, inflammation and injury scores were similar between the two groups. These results suggest that bevacizumab-eluting stent implantation in rabbit iliac arteries is safe, and inhibits neovascularization without affecting the endothelialization.

A Large Posttraumatic Subclavian Artery Aneurysm Complicated by Artery Occlusion and Arteriobronchial Fistula Successfully Treated Using a Covered Stent

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stefanczyk, Ludomir, E-mail: stefanczyk_l@wp.pl; Czeczotka, Jaroslaw; Elgalal, Marcin

2011-02-15

The treatment of posttraumatic aneurysms of peripheral arteries using covered stents is increasingly commonplace. We present the case of a 10-year-old girl with a pseudoaneurysm of the subclavian artery complicated by an arteriobronchial fistula with hemorrhaging into the bronchial tree and distal subclavian artery occlusion. Despite the lack of artery patency, endovascular stent graft implantation was successful. Pseudoaneurysm exclusion and involution was achieved, together with a patent implant and maintained collateral circulation patency.

Angiographic and Interventional Management for a Esophagopericardial Fistula

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Keng, E-mail: zjwukeng@hotmail.com; You, Qiong, E-mail: qiong_you@yahoo.cn; He, Song-Jian

2013-06-19

We reported a case of a 78-year-old patient with esophagopericardial fistula who was referred for angiographic and interventional management. Emergent implantation of the esophageal stent could not lengthen or even save the patient’s life. One week later, the patient died of multiple organ failure, which was probably from formation of granulation tissue and stent migration. Therefore, if the inflammatory to the esophagopericardial fistula had been better controlled initially, and the implantation of the esophageal stent delayed, our patient would have survived.

Aortobronchial fistula caused by an endobronchial lobar Y stent: a word of caution.

PubMed

Härting, Margarete; Welter, Stefan; Aigner, Clemens

2018-04-25

A 17-year-old female patient with a history of pulmonary tuberculosis was admitted with progressive dyspnoea and haemoptysis. Five months prior to admission, a left bronchial carina Y stent was implanted. Because of the already destroyed parenchyma, a pneumonectomy was planned. Intraoperatively, an aortobronchial fistula was discovered as the source of bleeding, which could be stopped by pledget-armed sutures. The formation of an aortobronchial fistula has to be considered as a potential source of endobronchial bleeding after stent implantation.

Stenting and surgery for coronary vasospasm : the wrong solution fails to solve the problem.

PubMed

Nedeljkovic, Milan A; Ostojic, Miodrag; Lalic, Nebojsa; Beleslin, Branko; Nedeljkovic, Ivana; Lalic, Katarina; Ristic, Miljko; Giga, Vojislav; Angelkov, Lazar; Tomasevic, Miloje; Kanjuh, Vladimir

2009-11-01

A 55-year-old man, with a history of medically uncontrolled coronary vasospasm, presented for evaluation of chest pain 6 months after implantation of left internal mammary artery. Due to recurrent episodes of vasospastic angina and serious complications of coronary spasm (ventricular fibrillation, myocardial infarction), a stent had previously been implanted in the proximal part of left anterior descending artery at the site of angiographically and ergonovine-proven coronary spasm, with subsequent in-stent restenosis.

Distribution of nickel after modified nitinol stent implantation in animals

NASA Astrophysics Data System (ADS)

Chepeleva, E.; Sergeevichev, D.; Lotkov, A.; Kashin, O.; Korobeynikov, A.; Kozyr, K.; Baystrukov, V.; Zubarev, D.; Kretov, E.; Pokushalov, E.

2017-09-01

Intravascular stenting of arteries in atherosclerotic lesions is one of the most frequently performed procedures in cardiovascular surgery today. Most stents are made of various stainless-steel alloys and other metals (such as nitinol). Nitinol is a biocompatible, superplastic and corrosion resistant material with an important feature of shape memory. However, the composition of this alloy includes nickel, which shows toxicity to the kidneys, liver, lungs, heart and other organs when it accumulates in the organism. In this research we investigated the nickel content in serum, urine and hair of the laboratory animals after implantation of nitinol stents treated with plasma ionic surface modification by silicon.

[Use of esophageal small balloon or papillary sphincter knife in the treatment of stent implantation 
for colorectal malignant obstruction].

PubMed

Xiao, Dinghua; Liu, Shaojun; Yan, Hanguang; Wang, Xiaoyan

2018-05-28

To explore the function of esophageal small balloon or papillary sphincter knife in the treatment of stent implantation for colorectal malignant obstruction, and to improve the success rate of colonic stent placement in such patients.
 Methods: A total of 49 patients with colorectal cancer complicated with almost complete obstruction or colorectal cancer were enrolled for this study. The esophageal small balloon or papillary sphincter knife was used in the guide wires. The guide wires gradually crossed the tumor gap and they were placed in the contralateral intestinal cavity with balloon progression. X-ray was then used to confirm whether the guide wire was inserted in the lesion intestinal cavity, and then the metal bare stent was inserted.
 Results: The guide wires was successfully inserted with conventional methods in these 49 cases, while they were also successfully placed the guide wire and the stent in the new way.
 Conclusion: For the patients with colorectal cancer complicated with complete obstruction or colorectal cancer located in obviously angled location, the use of esophageal small balloon or papillary sphincter knife can help the guide wire insert. They greatly improve the success rate of stent implantation.

PEACE I all-comers registry: patency evaluation after implantation of the 4-French Pulsar-18 self-expanding nitinol stent in femoropopliteal lesions.

PubMed

Lichtenberg, Michael; Kolks, Oliver; Hailer, Birgit; Stahlhoff, Wilhelm-Friedrich; Tiefenbacher, Christiane; Nolte-Ernsting, Claus; Arjumand, Jawed; Wittenberg, Guenther

2014-06-01

To evaluate the 1-year patency of the 4-F Pulsar-18 self-expanding nitinol stent for treatment of femoropopliteal occlusive disease in a national, prospective, multicenter, all-comers registry. Between January and June 2012, the German PEACE I all-comers prospective registry enrolled 148 patients with symptomatic femoropopliteal lesions (Rutherford category 2-5) undergoing recanalization and implantation of the Pulsar-18 SE nitinol stent at 6 clinical centers. Thirty patients did not have the 12-month follow-up visit (18 declined reevaluation, 5 withdrew consent, and 7 died), leaving 118 patients (64 men; mean 71.9±9.6 age years) for the 1-year evaluation. The average lesion length was 111.5±71.4 mm, and 38 of the 118 lesions were classified as TASC II D. More than half the lesions (67, 56.7%) were chronic total occlusions (CTO). The popliteal segment was involved in 22 (18.7%) lesions. The mean stented length was 122.7±64.5 mm. Routine follow-up included duplex ultrasound at 6 and 12 months. Outcome measures were primary patency and no clinically driven target lesion revascularization (TLR) within 12 months. The overall primary patency rates after 6 and 12 months were 87.4% and 79.5%, respectively; in the popliteal segments, the rate was 71.4% after 12 months. The overall freedom from TLR was 93.2% after 6 months and 81% after 12 months. Ankle-brachial index, pain-free walking distance, and Rutherford category all improved significantly (p<0.0001) after 6 and 12 months. The primary patency rates in patients with diabetes (p=1.0) and those with renal insufficiency (p=0.8) were not significantly lower compared to the overall rate. There was no significant difference (p=0.67) in restenosis rate for recanalization of CTOs compared to non-CTO lesions. In this all-comers registry, the use of the Pulsar-18 self-expanding nitinol stent in femoropopliteal lesions averaging 111.5 mm long showed promising primary patency and freedom from TLR after 6 and 12 months. Diabetes had no negative impact on patency. Primary patency in the popliteal segments was acceptable at 12 months.

[Experimental study of an intratracheal stent made of shape memory alloy].

PubMed

Yoshimura, M; Tsugawa, C; Tsubota, N

1994-11-01

To develop a new prosthesis for treating tracheal stenosis and tracheobronchomalacia, we examined the usefulness of an intratracheal stent made of shape memory alloy (SMA), a titanium-nickel alloy composed of 50% of each metal. At its recovery temperature (37 degrees C), the SMA stent was designed to recall the memorized shape of a coil with a diameter of 5 or 6 mm and a length of 10 mm. For the present experiment, it was transformed to a smaller coil 3 mm in diameter at a low temperature (-50 degrees C) and then loaded into the prosthesis introducer tube. An experimental model of potentially fatal tracheomalacia was made surgically by cutting and fracturing the tracheal cartilages of rabbits and tracheal collapse was confirmed by rigid bronchoscope. The introducer tube with the SMA stent was inserted and then the prosthesis was advanced into the collapsed segment of the trachea using the stent pusher. The SMA stent warmed bo body temperature and recovered its memorized shape after 1-2 min. In 3 out of 8 rabbits, follow-up bronchoscopy performed at 6, 8, and 10 months after implantation revealed satisfactory patency of the SMA stent and the trachea. After follow-up, 3 animals were sacrificed for histological observation, which showed little proliferation of granulation tissue and no dislocation of the SMA stent from the malacic portion. The remaining 5 rabbits have been followed for 18-24 months and are doing well. We conclude that the SMA stent maintains good tracheal patency, causes little reaction in the tracheal wall, and is easy to handle. Thus, it shows the potential for clinical application.

[Implantation of the paclitaxel-eluting stent Apollo in patients with stable angina pectoris: long-term angiographic and clinical results].

PubMed

Batyraliev, T A; Fettser, D V; Samko, A N; Sidorenko, B A

2010-01-01

to assess the long-term angiographic and clinical results of percutaneous coronary interventions (PCI) with implantation of the drug-eluting stent (DES) Apollo in patients with stable angina pectoris. The study enrolled 48 patients with stable angina who had been implanted with 59 stents. A follow-up of the patients lasted 12 months. The intervention was successful in 100% patients. Following 12 months, 81.3% of the patients underwent angiography that demonstrated that the vascular diameter decreased by 0.32 +/- 0.45 mm and the rate of restenosis was reduced by only 5.3%. The frequency of evident cardiac complications over 12 months was as high as 11.6%. The DES Apollo provides a way of safely performing PCI, by achieving a high of angiographic success rate. The application of this stent yields long-term good angiographic and clinical results in patients with stable angina pectoris.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sommer, C. M., E-mail: christof.sommer@med.uni-heidelberg.de; Grenacher, L.; Stampfl, U.

The purpose of this study was to evaluate the impact of stent design on in-stent stenosis in rabbit iliac arteries. Four different types of stent were implanted in rabbit iliac arteries, being different in stent design (crown or wave) and strut thickness (50 or 100 {mu}m). Ten stents of each type were implanted. Each animal received one crown and one wave stent with the same strut thickness. Follow-up was either 12 weeks (n = 10 rabbits) or 24 weeks (n = 10 rabbits). Primary study end points were angiographic and microscopic in-stent stenosis. Secondary study end points were vessel injury,more » vascular inflammation, and stent endothelialization. Average stent diameter, relative stent overdilation, average and minimal luminal diameter, and relative average and maximum luminal loss were not significantly different. However, a trend to higher relative stent overdilation was recognized in crown stents compared to wave stents. A trend toward higher average and minimal luminal diameter and lower relative average and maximum luminal loss was recognized in crown stents compared to wave stents with a strut thickness of 100 {mu}m. Neointimal height, relative luminal area stenosis, injury score, inflammation score, and endothelialization score were not significantly different. However, a trend toward higher neointimal height was recognized in crown stents compared to wave stents with a strut thickness of 50 {mu}m and a follow-up of 24 weeks. In conclusion, in this study, crown stents seem to trigger neointima. However, the optimized radial force might equalize the theoretically higher tendency for restenosis in crown stents. In this context, also more favorable positive remodeling in crown stents could be important.« less

A comparison of the temporary placement of 3 different self-expanding stents for the treatment of refractory benign esophageal strictures: a prospective multicentre study

PubMed Central

2012-01-01

Background Refractory benign esophageal strictures (RBESs) have been treated with the temporary placement of different self-expanding stents with conflicting results. We compared the clinical effectiveness of 3 types of stents: self-expanding plastic stents (SEPSs), biodegradable stents, and fully covered self-expanding metal stents (FCSEMSs), for the treatment of RBES. Methods This study prospectively evaluated 3 groups of 30 consecutive patients with RBESs who underwent temporary placement of either SEPSs (12 weeks, n = 10), biodegradable stents (n = 10) or FCSEMSs (12 weeks, n = 10). Data were collected to analyze the technical success and clinical outcome of the stents as evaluated by recurrent dysphagia, complications and reinterventions. Results Stent implantation was technically successful in all patients. Migration occurred in 11 patients: 6 (60%) in the SEPS group, 2 (20%) in the biodegradable group and 3 (30%) in the FCSEMS group (P = 0.16). A total of 8/30 patients (26.6%) were dysphagia-free after the end of follow-up: 1 (10%) in the SEPS group, 3 (30%) in the biodegradable group and 4 (40%) in the FCSEMS group (P = 0.27). More reinterventions were required in the SEPS group (n = 24) than in the biodegradable group (n = 13) or the FCSEMS group (n = 13) (P = 0.24). Multivariate analysis showed that stricture length was significantly associated with higher recurrence rates after temporary stent placement (HR = 1.37; 95% CI = 1.08-1.75; P = 0.011). Conclusions Temporary placement of a biodegradable stent or of a FCSEMS in patients with RBES may lead to long-term relief of dysphagia in 30 and 40% of patients, respectively. The use of SEPSs seems least preferable, as they are associated with frequent stent migration, more reinterventions and few cases of long-term improvement. Additionally, longer strictures were associated with a higher risk of recurrence. PMID:22691296

Clinical Outcomes of Ahmed Glaucoma Valve Implantation Using Tube Ligation and Removable External Stents

PubMed Central

Lee, Jong Joo; Kim, Dong Myung; Kim, Tae Woo

2009-01-01

Purpose To investigate the immediate and long-term outcomes of Ahmed glaucoma valve (AGV) implantation with silicone tube ligation and removable external stents. Methods This retrospective non-comparative study investigated the outcomes of AGV implantation with silicone tube ligation and removable external stents in 95 eyes (90 patients) with at least 12 months of postoperative follow-up. Qualified success was defined as an intraocular pressure (IOP) of ≤21 mmHg and ≥6 mmHg regardless of anti-glaucoma medication. Those who required additional glaucoma surgery, implant removal or who had phthisis bulbi were considered failures. Hypotony was defined as an IOP of <6 mmHg. Results Mean IOP reduced from 37.1±9.7 mmHg preoperatively to 15.2±5.6 mmHg at 12 months postoperatively (p<0.001). Qualified success was achieved in 84.2% at 1 year. Hypotony with an IOP of <6 mmHg was seen in 8.4% and an IOP of <5 mmHg in 3.2% on the first postoperative day. No case of hypotony required surgical intervention. Suprachoroidal hemorrhage did not occur in this study. When stents were removed on the first postoperative day because of an insufficient IOP decrease, the mean IOP decreased significantly from 42.0 mmHg to 14.1 mmHg (p<0.001) after 1 hour. The most common complication was hyphema, which occurred in 17.9%. Conclusions Hypotony-related early complications requiring surgical intervention were reduced by ligation and external stents in the tube. In addition, early postoperative high IOPs were managed by removing external stents. The described method can prevent postoperative hypotony after AGV implantation and showed long-term success rates comparable to those reported previously. PMID:19568356

Clinical outcomes of Ahmed glaucoma valve implantation using tube ligation and removable external stents.

PubMed

Lee, Jong Joo; Park, Ki Ho; Kim, Dong Myung; Kim, Tae Woo

2009-06-01

To investigate the immediate and long-term outcomes of Ahmed glaucoma valve (AGV) implantation with silicone tube ligation and removable external stents. This retrospective non-comparative study investigated the outcomes of AGV implantation with silicone tube ligation and removable external stents in 95 eyes (90 patients) with at least 12 months of postoperative follow-up. Qualified success was defined as an intraocular pressure (IOP) of or=6 mmHg regardless of anti-glaucoma medication. Those who required additional glaucoma surgery, implant removal or who had phthisis bulbi were considered failures. Hypotony was defined as an IOP of <6 mmHg. Mean IOP reduced from 37.1+/-9.7 mmHg preoperatively to 15.2+/-5.6 mmHg at 12 months postoperatively (p<0.001). Qualified success was achieved in 84.2% at 1 year. Hypotony with an IOP of <6 mmHg was seen in 8.4% and an IOP of <5 mmHg in 3.2% on the first postoperative day. No case of hypotony required surgical intervention. Suprachoroidal hemorrhage did not occur in this study. When stents were removed on the first postoperative day because of an insufficient IOP decrease, the mean IOP decreased significantly from 42.0 mmHg to 14.1 mmHg (p<0.001) after 1 hour. The most common complication was hyphema, which occurred in 17.9%. Hypotony-related early complications requiring surgical intervention were reduced by ligation and external stents in the tube. In addition, early postoperative high IOPs were managed by removing external stents. The described method can prevent postoperative hypotony after AGV implantation and showed long-term success rates comparable to those reported previously.

Trabecular micro-bypass stent implantation during small-incision cataract surgery for open-angle glaucoma or ocular hypertension: Long-term results.

PubMed

Neuhann, Tobias H

2015-12-01

To evaluate long-term safety and efficacy of iStent trabecular micro-bypass stent implantation during cataract surgery in patients with primary open-angle, pseudo-exfoliation glaucoma, ocular hypertension, or secondary or post-traumatic glaucoma. AaM Augenklinik am Marienplatz, Munich, Germany. Prospective, open-label, non-randomized study. Preoperative and postoperative evaluations included intra-ocular pressure (IOP), topical ocular hypotensive medication use, cup/disc ratio, corrected-distance visual acuity (CDVA), complications, and adverse events. A single trabecular micro-bypass stent was implanted through the same temporal, limbal incision used for cataract surgery via phacoemulsification in a consecutive series of 62 eyes of 43 patients. To date, a total of 41 eyes have been followed for 3 years postoperatively, whereas long-term postoperative follow-up on the remaining patients is ongoing. Mean preoperative IOP was 24.1 ± 6.9 mm Hg on a mean of 1.8 medications (±0.9). Analyses of eyes with no secondary surgical intervention showed mean IOP reduction to 14.8 ± 4.2 mm Hg at 12 months (n = 61), 14.5 ± 2.2 mm Hg at 24 months (n = 42), and 14.9 ± 2.3 mm Hg at 36 months (n = 39). Medications were eliminated in 74% of eyes at 36 months. Five eyes, 4 with previous glaucoma surgeries and 1 with pseudo-exfoliation syndrome, required additional glaucoma surgery after stent implantation. No intra-operative or postoperative complications typically seen with conventional glaucoma surgeries occurred after stent implantation. At 36 months, CDVA was 20/40 or better in 38 eyes (93%). Trabecular micro-bypass stent implantation during cataract surgery was safe and effective in patients with ocular hypertension or glaucoma as measured by a sustained reduction in IOP and medication use and an excellent safety profile through 3 years after surgery. Dr. Neuhann has no financial or proprietary interest in any material or method mentioned. Glaukos Corp. provided editorial assistance in the preparation of the manuscript. Copyright © 2015 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Clinical Outcomes of Drug-Coated Balloons in Coronary Artery Disease Unsuitable for Drug-Eluting Stent Implantation.

PubMed

Iijima, Raisuke; Kougame, Norihiro; Hara, Hidehiko; Moroi, Masao; Nakamura, Masato

2018-06-12

The aim of this study was to investigate whether drug-coated balloon (DCB) treatment is effective for de novo coronary lesions that are unsuitable for drug-eluting stent (DES) implantation.Methods and Results:This retrospective study included 118 de novo lesions that were not suitable for DES implantation. Of the lesions, 40% was treated because of very small vessel disease. Patients with planned non-cardiac surgery and at high bleeding risk were 3% and 19%, respectively, and lesions that easily develop stent fracture comprised 26%. Clinically driven target lesion revascularization (TLR) was the primary endpoint. The rate of suboptimal lesion preparation before DCB treatment was set as the secondary endpoint. Optimal lesion preparation was defined as acquisition of Thrombolysis in Myocardial Infarction flow grade 3, minor coronary dissection, and residual stenosis ≤30%. The rate of suboptimal lesion preparation was 2.5% and 3 patients needed bail-out stenting. Accordingly, 115 patients were treated with a DCB. Clinically driven TLR had occurred in 8 patients (7.0%) at the 8-month follow-up. The presence of chronic total occlusion was identified as an independent predictor for TLR (odds 11.57; 95% confidence interval, 1.38-135.54; P=0.02). For lesions that are unsuitable for stent implantation, stent-less intervention using a DCB should be considered initially. The present study also highlighted that lesion preparation is key to a successful DCB strategy.

Constraining OCT with Knowledge of Device Design Enables High Accuracy Hemodynamic Assessment of Endovascular Implants.

PubMed

O'Brien, Caroline C; Kolandaivelu, Kumaran; Brown, Jonathan; Lopes, Augusto C; Kunio, Mie; Kolachalama, Vijaya B; Edelman, Elazer R

2016-01-01

Stacking cross-sectional intravascular images permits three-dimensional rendering of endovascular implants, yet introduces between-frame uncertainties that limit characterization of device placement and the hemodynamic microenvironment. In a porcine coronary stent model, we demonstrate enhanced OCT reconstruction with preservation of between-frame features through fusion with angiography and a priori knowledge of stent design. Strut positions were extracted from sequential OCT frames. Reconstruction with standard interpolation generated discontinuous stent structures. By computationally constraining interpolation to known stent skeletons fitted to 3D 'clouds' of OCT-Angio-derived struts, implant anatomy was resolved, accurately rendering features from implant diameter and curvature (n = 1 vessels, r2 = 0.91, 0.90, respectively) to individual strut-wall configurations (average displacement error ~15 μm). This framework facilitated hemodynamic simulation (n = 1 vessel), showing the critical importance of accurate anatomic rendering in characterizing both quantitative and basic qualitative flow patterns. Discontinuities with standard approaches systematically introduced noise and bias, poorly capturing regional flow effects. In contrast, the enhanced method preserved multi-scale (local strut to regional stent) flow interactions, demonstrating the impact of regional contexts in defining the hemodynamic consequence of local deployment errors. Fusion of planar angiography and knowledge of device design permits enhanced OCT image analysis of in situ tissue-device interactions. Given emerging interests in simulation-derived hemodynamic assessment as surrogate measures of biological risk, such fused modalities offer a new window into patient-specific implant environments.

One Year Outcomes of 101 BeGraft Stent Grafts used as Bridging Stents in Fenestrated Endovascular Repairs.

PubMed

Spear, Rafaelle; Sobocinski, Jonathan; Hertault, Adrien; Delloye, Matthieu; Azzauiu, Richard; Fabre, Dominique; Haulon, Stéphan

2018-04-01

To evaluate the outcomes of the second generation BeGraft balloon expandable covered stent Graft System (Bentley InnoMed, Hechingen, Germany) implanted as bridging stent grafts during fenestrated endovascular aortic repair (FEVAR) of complex aneurysms. This was a single centre prospective study including all consecutive patients treated by FEVAR performed with second generation BeGraft stent grafts as bridging stents. Demographics of patients, diameter and length of the bridging stent grafts, technical success, re-interventions, occlusions, post-operative events, and imaging (Cone Beam CT and/or CT scan, and contrast enhanced ultrasound) were prospectively collected in an electronic database. Duplex ultrasound was performed before discharge and at 6 month follow-up. At 1 year, patients were evaluated clinically and by imaging (CT and ultrasound). Between November 2015 and September 2016, 39 consecutive patients (one woman) were treated with custom made fenestrated endografts (2-5 fenestrations) for complex aneurysms or type 1 endoleak after EVAR, using a variety of bridging stents including the BeGraft. All 101 BeGraft stent grafts were successfully delivered and deployed. There was no in hospital mortality. Early fenestration patency rate was 99% (96/97); the sole target vessel post-operative occlusion was secondary to a dissection of the renal artery distal to the stent. Complementary stenting was unsuccessful in recovering renal artery patency; bilateral renal stent occlusion was observed in the same patient on a CT scan performed 2 months after the procedure. He required post-operative dialysis. No additional renal impairment was observed. During follow-up (median 13 months [11-15]), all fenestrations stented with BeGraft stent grafts remained patent (95/97, 98%). One type 1b endoleak was detected and treated (2.6%). BeGraft stent grafts used as bridging stents during FEVAR are associated with favourable outcomes at 1 year follow-up. Long-term follow-up is required to confirm these promising results. Copyright © 2018 European Society for Vascular Surgery. Published by Elsevier B.V. All rights reserved.

An improved methodology for investigating the parameters influencing migration resistance of abdominal aortic stent-grafts.

PubMed

Corbett, Timothy J; Callanan, Anthony; O'Donnell, Michael R; McGloughlin, Tim M

2010-02-01

To develop an improved methodology for investigating the parameters influencing stent-graft migration, with particular focus on the limitations of existing methods. A physiological silicone rubber abdominal aortic aneurysm (AAA) model for fixation studies was manufactured based on an idealized AAA geometry: the model had a 24-mm neck, a 50-mm aneurysm, 12-mm-diameter legs, a 60 degrees bifurcation angle, and 2-mm-thick walls. The models were authenticated in neck fixation experiments. The displacement force required to migrate stent-grafts in physiological pulsatile flow was tested dynamically in water at 37 degrees C. A commercially available longitudinally rigid stent-graft (AneuRx) and a homemade device with little longitudinal rigidity were studied in a number of different configurations to investigate the effect of neck fixation length and systolic pressure on displacement force. The AneuRx (6.95+/-0.49 to 8.52+/-0.5 N) performed significantly better than the homemade device (2.57+/-0.11 to 4.62+/-0.25 N) in pulsatile flow. The opposite was true in the neck fixation tests because the longitudinal stiffness of the AneuRx was not accounted for. Increasing pressure or decreasing fixation length compromised the fixation of the homemade device. This relationship was not as clear for the AneuRx because decreasing proximal fixation resulted in an increase in iliac fixation, which could assist fixation in this device. Assessing the migration resistance of stent-grafts based solely on proximal fixation discriminates against devices that are longitudinally stiff. Current in vivo models may give inaccurate displacement forces due to the high degree of oversizing in these studies. A novel in vitro approach, accounting for longitudinal rigidity and realistic graft oversizing, was developed to determine the resistance of aortic stent-grafts to migration in the period immediately after device implantation.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang Zhongmin, E-mail: wzm0722@hotmail.com; Huang Xunbo, E-mail: huangxunbo0722@hotmail.com; Cao Jun, E-mail: caojun88888@hotmail.com

Objective: This study was designed to compare the clinical effectiveness of intraluminal radioactive stent loaded with iodine-125 seeds implantation versus covered stent alone insertion in patients with malignant esophageal stricture. Methods: We studied two groups of patients with malignant esophageal stricture. Group A comprised 28 patients (19 men and 9 women) who underwent intraluminal radioactive stent loaded with iodine-125 seeds implantation and were followed prospectively. Group B comprised 30 patients (18 men and 12 women) who had previously received covered stent alone insertion; these patients were evaluated retrospectively. There was no crossover between the two groups during follow-up. Informed consentmore » was obtained from each patient, and our institutional review board approved the study. The dysphagia score, overall survival rates, complication rates, and reintervention rates were compared in the two groups. Results: There were no significant differences between the two groups in terms of baseline characteristics. Stent placement was technically successful and well tolerated in all patients. The dysphagia score was improved in both groups after stent placement. The median survival was significantly longer in group A than in group B: 11 versus 4.9 months, respectively (P < 0.001). The complications of chest pain, esophageal reflux, and stent migration was more frequent in group B, but this difference did not reach statistical significance. There was no statistical difference in reintervention between two groups. Conclusions: Intraluminal radioactive stent loaded with iodine-125 seeds implantation was a feasible and practical management in treating malignant esophageal stricture and was superior to covered stent alone insertion, as measured by survival.« less

SEMS vs cSEMS in duodenal and small bowel obstruction: High risk of migration in the covered stent group

PubMed Central

Waidmann, Oliver; Trojan, Jörg; Friedrich-Rust, Mireen; Sarrazin, Christoph; Bechstein, Wolf Otto; Ulrich, Frank; Zeuzem, Stefan; Albert, Jörg Gerhard

2013-01-01

AIM: To compare clinical success and complications of uncovered self-expanding metal stents (SEMS) vs covered SEMS (cSEMS) in obstruction of the small bowel. METHODS: Technical success, complications and outcome of endoscopic SEMS or cSEMS placement in tumor related obstruction of the duodenum or jejunum were retrospectively assessed. The primary end points were rates of stent migration and overgrowth. Secondary end points were the effect of concomitant biliary drainage on migration rate and overall survival. The data was analyzed according to the Strengthening the Reporting of Observational Studies in Epidemiology guidelines. RESULTS: Thirty-two SEMS were implanted in 20 patients. In all patients, endoscopic stent implantation was successful. Stent migration was observed in 9 of 16 cSEMS (56%) in comparison to 0/16 SEMS (0%) implantations (P = 0.002). Stent overgrowth did not significantly differ between the two stent types (SEMS: 3/16, 19%; cSEMS: 2/16, 13%). One cSEMS dislodged and had to be recovered from the jejunum by way of laparotomy. Time until migration between SEMS and cSEMS in patients with and without concomitant biliary stents did not significantly differ (HR = 1.530, 95%CI 0.731-6.306; P = 0.556). The mean follow-up was 57 ± 71 d (range: 1-275 d). CONCLUSION: SEMS and cSEMS placement is safe in small bowel tumor obstruction. However, cSEMS is accompanied with a high rate of migration in comparison to uncovered SEMS. PMID:24115817

Randomized comparison of Zotarolimus-Eluting Endeavor Sprint versus bare-metal stent implantation in uncertain drug-eluting stent candidates: rationale, design, and characterization of the patient population for the Zotarolimus-eluting Endeavor Sprint stent in uncertain DES candidates study.

PubMed

Valgimigli, Marco; Patialiakas, Athanasios; Thury, Attila; Colangelo, Salvatore; Campo, Gianluca; Tebaldi, Matteo; Ungi, Imre; Tondi, Stefano; Roffi, Marco; Menozzi, Alberto; de Cesare, Nicoletta; Garbo, Roberto; Meliga, Emanuele; Testa, Luca; Gabriel, Henrique M; Airoldi, Flavio; Ferlini, Marco; Liistro, Francesco; Dellavalle, Antonio; Vranckx, Pascal; Briguori, Carlo

2013-11-01

The use of drug-eluting stent (DES) instead of bare-metal stent (BMS) in patients at high stent thrombosis or bleeding risk as well as in those at low restenosis risk (ie, uncertain DES candidates) remains a matter of debate. Zotarolimus-Eluting Endeavor Sprint stent (E-ZES) (Santa Rosa, CA) is a hydrophilic polymer-based second-generation device with unique drug fast-release profile, which may allow for a shorter dual antiplatelet therapy (DAPT) duration without safety concerns. The primary objective is to assess whether E-ZES implantation followed by a shorter than currently recommended course of DAPT will decrease the incidence of 12-month major adverse cardiovascular events as compared with BMS in undefined DES recipients. Actual duration of DAPT regimen will be dictated by patients' characteristics and not by stent type and, as such, can be as short as 30 days after intervention in both stent groups. The ZEUS study is an open-label randomized clinical trial conducted at 20 clinical sites in Italy, Switzerland, Portugal, and Hungary. With 1,600 individuals, this study will have 85% power to detect a 33% difference in the primary end point consisting of the composite of death, nonfatal myocardial infarction, or target vessel revascularization. The ZEUS trial aims to assess whether the use of E-ZES, followed by a DAPT duration regimen based on patients' characteristics and not by stent type, is superior to conventional BMS implantation in undefined DES recipients who qualify for the presence of high thrombosis, bleeding, or low restenosis risk criteria. © 2013.

Process for making electroformed stents

DOEpatents

Hines, Richard A.

2000-02-01

This invention is directed to an expandable stent useful for implantation into an artery or the like. The stents are made using electroforming techniques in which an electrically-conductive mandrel is coated with a suitable resist material, after which the resist is exposed to an appropriate light pattern and frequency so as to form a stent pattern in the resist. The mandrel is then electroplated with a suitable stent material. The mandrel is etched away once a sufficient layer of stent material is deposited, leaving a completed stent.

Management of stent dislodgment in coarctoplasty of aorta with three overlapping self-expandable nitinol stents.

PubMed

Ghazi, Payam; Haji-Zeinali, Ali-Mohammad

2010-01-01

We describe a case of native coarctation of aorta managed with three self-expandable nitinol stents. After balloon pre-dilation, the first and second stents were dislodged. The coarcted area was successfully treated with the third stent overlapped with the previous stents. During follow up (30 months), the patient was free of complications. It seems that implantation of multiple overlapping self-expandable stents in aortic coarctation patients, if needed, is safe and possible.

Polymer Hydrogel/Polybutadiene/Iron Oxide Nanoparticle Hybrid Actuators for the Characterization of NiTi Implants

PubMed Central

Jeličić, Aleksandra; Friedrich, Alwin; Jeremić, Katarina; Siekmeyer, Gerd; Taubert, Andreas

2009-01-01

One of the main issues with the use of nickel titanium alloy (NiTi) implants in cardiovascular implants (stents) is that these devices must be of very high quality in order to avoid subsequent operations due to failing stents. For small stents with diameters below ca. 2 mm, however, stent characterization is not straightforward. One of the main problems is that there are virtually no methods to characterize the interior of the NiTi tubes used for fabrication of these tiny stents. The current paper reports on a robust hybrid actuator for the characterization of NiTi tubes prior to stent fabrication. The method is based on a polymer/hydrogel/magnetic nanoparticle hybrid material and allows for the determination of the inner diameter at virtually all places in the raw NiTi tubes. Knowledge of the inner structure of the raw NiTi tubes is crucial to avoid regions that are not hollow or regions that are likely to fail due to defects inside the raw tube. The actuator enables close contact of a magnetic polymer film with the inner NiTi tube surface. The magnetic signal can be detected from outside and be used for a direct mapping of the tube interior. As a result, it is possible to detect critical regions prior to expensive and slow stent fabrication processes.

Safety of six-month dual antiplatelet therapy after second-generation drug-eluting stent implantation: OPTIMA-C Randomised Clinical Trial and OCT Substudy.

PubMed

Lee, Byoung-Kwon; Kim, Jung-Sun; Lee, Oh-Huyn; Min, Pil-Ki; Yoon, Young-Won; Hong, Bum-Kee; Shin, Dong-Ho; Kang, Tae-Soo; Kim, Byung Ok; Cho, Duk-Kyu; Jeon, Dong Woon; Woo, Sung-Ill; Choi, Seonghoon; Kim, Yong Hoon; Kang, Woong-Chol; Kim, Seunghwan; Kim, Byeong-Keuk; Hong, Myeong-Ki; Jang, Yangsoo; Kwon, Hyuck Moon

2018-03-20

There are few randomised studies concerning the optimal duration of dual antiplatelet therapy (DAPT) for patients who receive a second-generation drug-eluting stent (DES). This trial aimed to investigate the safety of six-month compared with 12-month DAPT maintenance after second-generation DES implantation. A prospective, randomised, multicentre trial was performed at 10 medical centres. The 1,368 patients included in the study received a biolimus-eluting stent (BES) or a zotarolimus-eluting stent (ZES). The primary outcome measured was the composite of major adverse cardiac events (MACE), including cardiac death, myocardial infarction (MI), or ischaemia-driven target lesion revascularisation at the 12-month follow-up. The secondary outcome was the percentage of uncovered struts at six months in 60 patients (30 ZES, 30 BES) using optical coherence tomography (OCT) assessment. Each patient was randomly assigned to six-month (n=684) or 12-month DAPT (n=684). Major adverse cardiac events at 12 months occurred in eight patients (1.2%) in the six-month DAPT group and in four patients (0.6%) in the 12-month DAPT group (risk difference 0.6%; 95% confidence interval [CI]: -0.4-1.6%; p=0.24). The upper 95% CI limit was lower than the pre-specified limit of 4% non-inferiority (p for non-inferiority <0.05). The percentage of uncovered struts was 3.16±4.30% at six months in 60 stents of 60 patients. After second-generation DES implantation, six-month DAPT was not inferior to 12-month DAPT in terms of MACE occurrence over the 12-month follow-up period. OCT examination revealed favourable stent strut coverage at six months after stent implantation.

[Cost-effectiveness trial of self-expandable metal stents and plastic biliary stents in malignant biliary obstruction].

PubMed

Daróczi, Tímea; Bor, Renáta; Fábián, Anna; Szabó, Ella; Farkas, Klaudia; Bálint, Anita; Czakó, László; Rutka, Mariann; Szűcs, Mónika; Milassin, Ágnes; Molnár, Tamás; Szepes, Zoltán

2016-02-14

Self-expandable metal and plastic stents can be applied in the palliative endoscopic treatment of patients with unresectable malignant biliary obstruction. The use of metal stentsis recommended if the patient's life expectancy is more than four months. To compare the therapeutic efficacy and cost-effectiveness of metal and plastic stents in the treatment of malignant biliary obstruction. The authors retrospectively enrolled patients who received metal (37 patients) or plastic stent (37 patients). The complication rate, stent patency and cumulative cost of treatment were assessed in the two groups. The complication rate of metal stents was lower (37.84% vs. 56.76%), but the stent patency was higher compared with plastic stents (19.11 vs. 8.29 weeks; p = 0.0041). In the plastic stent group the frequency of hospitalization of patients in context with stent complications (1.18 vs. 2.32; p = 0.05) and the necessity of reintervention for stent dysfunction (17 vs. 27; p = 0.033) were substantially higher. In this group multiple stent implantation raised the stent patency from 7.68 to 10.75 weeks. There was no difference in the total cost of treatment of malignant biliary obstruction between the two groups (p = 0.848). Considering the cost of treatment and the burden of patients the authors recommend self-expandable metal sten timplantation if the life expectancy of patients is more than two months. In short survival cases multiple plastic stent implantation is recommended.

Palliation double stenting for malignant biliary and duodenal obstruction

PubMed Central

ZHAO, LIANG; XU, HAITAO; ZHANG, YUBAO

2016-01-01

The surgical management of patients with malignant biliary and duodenal obstruction is complex. Tumor excision is no longer possible in the majority of patients with malignant obstructive jaundice and duodenal obstruction. The aim of the present study was to evaluate the effectiveness of intraluminal dual stent placement in malignant biliary and duodenal obstruction. In total, 20 patients with malignant obstructive jaundice and duodenal obstruction, including 6 with pancreatic carcinoma, 11 with cholangiocarcinoma, 1 with duodenal carcinoma and 2 with abdominal lymph node metastasis, were treated with intraluminal stent placement. Bile duct obstruction with late occurrence of duodenal obstruction was observed in 16 cases, and duodenal obstruction followed by a late occurrence of bile duct obstruction was observed in 3 cases, while, in 1 case, bile duct obstruction and duodenal obstruction occurred simultaneously. After X-ray fluoroscopy revealed obstruction in the bile duct and duodenum, stents were placed into the respective lumens. Percutaneous transhepatic placement was employed for the biliary stent, while the duodenal stent was placed perioraly. The clinical outcomes, including complications associated with the procedures and patency of the stents, were evaluated. The biliary and duodenal stents were successfully implanted in 18 patients and the technical success rate was 90% (18/20). A total of 39 stents were implanted in 20 patients. In 2 cases, duodenal stent placement failed following biliary stent placement. Duodenal obstruction remitted in 15 patients, and 1 patient succumbed to aspiration pneumonia 5 days after the procedure. No severe complications were observed in any other patient. The survival time of the 18 patients was 5–21 months (median, 9.6 months), and 6 of those patients survived for >12 months. The present study suggests that X-ray fluoroscopy-guided intraluminal stent implantation is an effective procedure for the treatment of malignant biliary and duodenal obstruction. PMID:26889267

The impact of overhead lines for employees with stents

NASA Astrophysics Data System (ADS)

Syrek, P.; Skowron, M.

2017-05-01

The aim of article is to discuss interaction between stents implanted in the body of worker and harmonic magnetic field in the vicinity of electric wires. In last decades, a growing proportion of people has any devices implanted, to list: cardiac pacemakers, cardioverter - defibrillators. Recommendations of International Commision on Non-ionizing Radiation Protection (ICNIRP), and resctrictions imposed in different states, may exlude specific individuals from their duties. The autors focused on the situation, when the employee with stent, works in the immediate vicinity of overhead electric wires, cleaning with dry ice the electric insulators.

Airport and superficial femoral artery obstruction due to a wandering coronary stent: the possibility of airport detection of modern implant metals.

PubMed

Teijink, J A W; van Herwaarden, J A; van den Berg, J C; Overtoom, T C; Moll, F L

2004-06-01

In the treatment of coronary artery disease, peripheral loss of a coronary stent is an unusual complication. We present the case of a patient who suggested that his right leg claudication was caused by a slipped coronary stent 2 years previously. The patient was convinced about this unusual finding based on an airport security check. Examination proved him to be right. However, the ability to detect an object using eddy currents is dependent on the object's permeability and its conductivity. Ferrous (iron) content is not the critical factor. Modern implant materials and processing techniques result in implants that are difficult to magnetize i.e. their permeability is very low. In addition their conductivity is very low. This enables modern implants to escape detection at airports. For this reason the event at the airport, as described by our patient, is considered coincidental.

Treatment of congenital tracheal stenosis by balloon-expandable metallic stents in paediatric intensive care unit

PubMed Central

Xu, Xuan; Li, Dandan; Zhao, Shuyu; Liu, Xicheng; Feng, Zhichun; Ding, Hui

2012-01-01

The aim of this study was to evaluate the use of balloon-expandable metallic stents in the treatment of children with congenital tracheal stenosis in whom conventional therapy has failed. From 2010 to 2011, balloon-expandable metallic stents were implanted into the trachea of eight infants aged 2–20 months in the paediatric intensive care unit. The infants had severe airway obstruction caused by congenital tracheal stenosis. Tracheal stents were placed after intraluminal balloon dilatation of the tracheal stenosis, inserted with balloon catheters and implanted into the desired position bronchoscopically. The stents were 12 to 29 mm long and 4 mm in diameter. Seven children were relieved of airway obstruction after this procedure. However, a child died due to severe sepsis after the placement of bronchial stents. No granulation tissue developed over the stents in any of the children. Stents have been in place for 1–6 months after insertion without any other complication. Balloon-expandable metallic stents are effective in relieving airway obstruction by congenital tracheal stenosis in children. This technique may provide an important remedy for congenital tracheal stenosis in children. PMID:22361127

The use of expandable metallic airway stents for tracheobronchial obstruction in children.

PubMed

Filler, R M; Forte, V; Fraga, J C; Matute, J

1995-07-01

Expandable metallic angioplasty stents (Palmaz stent) have been implanted in the trachea and/or bronchi of seven children. Three children had severe tracheal stenosis after tracheoplasty for congenital tracheal stenosis repair, and four had tracheomalacia or bronchomalacia with or without vascular compression. The mean age at stenting was 9.7 months (range, 2 to 15 months). Balloon expandable stents were inserted into the trachea or bronchus through a 3.5-mm bronchoscope under fluoroscopic control. Initially a single tracheal stent was used for all patients except for one with obstruction in the trachea and both bronchi, in whom three stents were implanted. Three children had recurrent airway obstruction 1 month later; one was cured with a second stent; one child died 1 year later; and the other is being treated for heart disease. The others have no serious respiratory problems. The stents in all have been in place for 1 to 25 (mean, 11) months. No immediate complications were noted. Early and late bronchoscopy showed incomplete epithelialization of the stent and patches of granulation tissue on it. Two stents were removed bronchoscopically, one at the completion of treatment for tracheomalacia and the other at the time of recurrent airway obstruction. This preliminary experience indicates that expandable metallic stents have a useful role in the treatment of selected lower airway obstructions.

Comparison of the long-term safety and efficacy of drug-eluting and bare-metal stent implantation in saphenous vein grafts.

PubMed

Latib, Azeem; Ferri, Luca; Ielasi, Alfonso; Cosgrave, John; Godino, Cosmo; Bonizzoni, Erminio; Romagnoli, Enrico; Chieffo, Alaide; Valgimigli, Marco; Penzo, Carlo; Carlino, Mauro; Michev, Iassen; Sangiorgi, Giuseppe M; Montorfano, Matteo; Airoldi, Flavio; Colombo, Antonio

2010-06-01

Concerns about the long-term safety of drug-eluting stents (DES) in saphenous vein grafts has become an area of controversy and uncertainty. In this retrospective registry, we compared the outcomes in 127 patients (143 lesions) treated with DES from April 2002 to June 2006 (DES group) with 131 patients (160 lesions) treated with bare-metal stents in the preceding 36 months (bare-metal stent group). End points analyzed were cumulative death, myocardial infarction, and target vessel revascularization at 2 years after stent implantation. The DES group was significantly (P<0.05) more complex with a greater frequency of diabetes (33.1%versus 15.3%), older grafts (11.6+/-5.3 years versus 9.6+/-5.2 years), restenotic lesions (23.8% versus 4.4%), total occlusions (7.7% versus 1.2%), and smaller grafts (3.16+/-0.66 mm versus 3.44+/-0.76 mm) treated with longer stents (34.1+/-25.1 mm versus 22.7+/-11.6 mm). At 2 years, there was no statistical difference in death (8.7% versus 7.8%), myocardial infarction (6.3% versus 9.4%), or target vessel revascularization (19.7% versus 24.2%) between DES and bare-metal stents, respectively. A propensity analysis to adjust for baseline differences suggested that there was no observed association between DES and increased mortality (hazard ratio, 0.72; 95% CI, 0.21 to 2.44; P=0.60) but possibly an association with a reduction in target vessel revascularization (hazard ratio, 0.31; 95% CI, 0.14 to 0.66; P=0.002). Despite being implanted in patients and lesions more complex than the bare-metal stent group, there was no observed association between DES implantation in saphenous vein grafts and an increase in late mortality. DES may maintain their efficacy in reducing revascularization rates in diseased saphenous vein grafts over a 2-year follow-up period.

Natural history of optical coherence tomography-detected non-flow-limiting edge dissections following drug-eluting stent implantation.

PubMed

Radu, Maria D; Räber, Lorenz; Heo, Jungho; Gogas, Bill D; Jørgensen, Erik; Kelbæk, Henning; Muramatsu, Takashi; Farooq, Vasim; Helqvist, Steffen; Garcia-Garcia, Hector M; Windecker, Stephan; Saunamäki, Kari; Serruys, Patrick W

2014-01-22

Angiographic evidence of edge dissections has been associated with a risk of early stent thrombosis. Optical coherence tomography (OCT) is a high-resolution technology detecting a greater number of edge dissections--particularly non-flow-limiting--compared to angiography. Their natural history and clinical implications remain unclear. The objectives of the present study were to assess the morphology, healing response, and clinical outcomes of OCT-detected edge dissections using serial OCT imaging at baseline and at one year following drug-eluting stent (DES) implantation. Edge dissections were defined as disruptions of the luminal surface in the 5 mm segments proximal and distal to the stent, and categorised as flaps, cavities, double-lumen dissections or fissures. Qualitative and quantitative OCT analyses were performed every 0.5 mm at baseline and one year, and clinical outcomes were assessed. Sixty-three lesions (57 patients) were studied with OCT at baseline and one-year follow-up. Twenty-two non-flow-limiting edge dissections in 21 lesions (20 patients) were identified by OCT; only two (9%) were angiographically visible. Flaps were found in 96% of cases. The median longitudinal dissection length was 2.9 mm (interquartile range [IQR] 1.6-4.2 mm), whereas the circumferential and axial extensions amounted to 1.2 mm (IQR: 0.9-1.7 mm) and 0.6 mm (IQR: 0.4-0.7 mm), respectively. Dissections extended into the media and adventitia in seven (33%) and four (20%) cases, respectively. Eighteen (82%) OCT-detected edge dissections were also evaluated with intravascular ultrasound which identified nine (50%) of these OCT-detected dissections. No stent thrombosis or target lesion revascularisation occurred up to one year. At follow-up, 20 (90%) edge dissections were completely healed on OCT. The two cases exhibiting persistent dissection had the longest flaps (2.81 mm and 2.42 mm) at baseline. OCT-detected edge dissections which are angiographically silent in the majority of cases are not associated with acute stent thrombosis or restenosis up to one-year follow-up.

Use of PTFE Stent Grafts for Hemodialysis-related Central Venous Occlusions: Intermediate-Term Results

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kundu, Sanjoy, E-mail: sanjoy_kundu40@hotmail.com; Modabber, Milad; You, John M.

2011-10-15

Purpose: To assess the safety and effectiveness of a polytetrafluoroethylene (PTFE) encapsulated nitinol stents (Bard Peripheral Vascular, Tempe, AZ) for treatment of hemodialysis-related central venous occlusions. Materials and Methods: Study design was a single-center nonrandomized retrospective cohort of patients from May 2004 to August 2009 for a total of 64 months. There were 14 patients (mean age 60 years, range 50-83 years; 13 male, 1 female). All patients had autogenous fistulas. All 14 patients had central venous occlusions and presented with clinical symptoms of the following: extremity swelling (14%, 2 of 14), extremity and face swelling (72%, 10 of 14),more » and face swelling/edema (14%, 2 of 14). There was evidence of access dysfunction with decreased access flow in 36% (5 of 14) patients. There were prior interventions or previous line placement at the site of the central venous lesion in all 14 patients. Results were assessed by recurrence of clinical symptoms and function of the access circuit (National Kidney Foundation recommended criteria). Results: Sixteen consecutive straight stent grafts were implanted in 14 patients. Average treated lesion length was 5.0 cm (range, 0.9-7 cm). All 14 patients had complete central venous occlusion (100% stenosis). The central venous occlusions were located as follows: right subclavian and brachiocephalic vein (21%, 3 of 14), right brachiocephalic vein (36%, 5 of 14), left brachiocephalic vein (36%, 5 of 14), and bilateral brachiocephalic vein (7%, 1 of 14). A total of 16 PTFE stent grafts were placed. Ten- or 12-mm-diameter PTFE stent grafts were placed. The average stent length was 6.1 cm (range, 4-8 cm). Technical (deployment), anatomic (<30% residual stenosis), clinical (resolution of symptoms), and hemodynamic (resolution of access dysfunction) success were 100%. At 3, 6, and 9 months, primary patency of the treated area and access circuit were 100% (14 of 14). Conclusions: This PTFE encapsulated stent graft demonstrates encouraging intermediate-term patency results for central vein occlusions. Further prospective studies with long-term assessment and larger patient populations will be required.« less

Superficial femoral artery TASC D Registry: twelve-month effectiveness analysis of the Pulsar-18 SE nitinol stent in patients with critical limb ischemia.

PubMed

Lichtenberg, M; Stahlhoff, W; Boese, D

2013-08-01

Single center observational study analyzing the primary patency rate and freedom from target lesions revascularization rate of the Pulsar-18 nitinol stent after recanalization of long superficial femoral artery (SFA) occlusions (TASC D) in 22 patients with critical limb ischemia (CLI). Between 1/2011 and 7/2011, 22 consecutive patients (9 male, 13 female) with chronic total occlusions (CTO) of the femoro-popliteal arteries presenting with CLI (17 patients with Rutherford 4 score, and 5 patients with Rutherford 5 score) were enrolled and successfully recanalized using the Pulsar-18 self-expanding (SE) nitinol stent (BIOTRONIK AG, Buelach, Switzerland). Primary patency at 12 months was defined as no binary restenosis (>50%) on Duplex ultrasound (PSVR<2.5) and respectively no target lesion revascularization performed within 12 months. The average lesion length of the treated femoro-popliteal segment was 315 mm. Performing spot stenting average stent length in all patients was 245 mm (minimal 215 mm, maximal 315 mm). Technical success, with establishing an antegrade straight line flow to the foot through a reopened SFA, was achieved in all 22 patients. Subintimal and intraluminal recanalization techniques were used. Two patients with Rutherford 5 score had a minor amputation shortly after the recanalization procedure. All other patients had a complete wound healing of their lesions during a 6 month follow-up. After 12 month follow-up the primary patency rate of the Pulsar-18 SE nitinol stent was 77% with a per protocol restenosis in 5 of 22 patients. Seventeen patients showed a walking capacity on treadmill test >300 meters (Rutherford II). Two patients with a documented restenosis were Rutherford, these patients were treated conservatively. Three patients with restenosis and a Rutherford III score were scheduled for an endovascular target lesion revascularization leading to a freedom from target lesion revascularization rate of 86%. Endovascular intervention of long SFA occlusions using subintimal or intraluminal recanalization technique with implantation of the Pulsar-18 SE nitinol stent in CLI patients is safe and clinically effective with a primary patency rate after 12 months of 77% and a freedom from target lesion revascularization rate of 86%.

Results From the VISIBILITY Iliac Study: Primary and Cohort Outcomes at 9 Months

PubMed Central

Rundback, John H.; Peeters, Patrick; George, Jon C.; Jaff, Michael R.; Faries, Peter L.

2017-01-01

Purpose: To evaluate the safety and effectiveness of primary stenting of the common (CIA) or external iliac artery (EIA) using the Visi-Pro Balloon-Expandable Peripheral Stent System for treatment of stenotic, restenotic, or occluded lesions. Methods: Between 2011 and 2012, 75 patients (mean age 64.2±8.9 years; 46 men) with Rutherford category 2–4 ischemia and atherosclerotic lesions ≤10 cm in length underwent iliac artery stenting at 17 centers in the United States and Europe. The primary outcome of the study was the major adverse event (MAE) rate at 9 months postprocedure [composite of periprocedural death, in-hospital myocardial infarction, clinically driven target lesion revascularization (CD-TLR), and amputation of the treated limb]. Secondary outcomes included 30-day MAE rate, 9-month primary patency, changes in ankle-brachial index (ABI) and the Walking Impairment Questionnaire at 30 days and 9 months postprocedure, device success, and clinically driven target vessel revascularization (CD-TVR) at 30 days and 9 months. Outcomes in specific patient cohorts (ie, gender, stent location, calcification severity, and lesion grade) were analyzed. Results: Eighty-one stents were implanted in 61 CIA and 15 EIA lesions (41 with moderate/severe calcification). The mean lesion treated length was 29.3±13.9 mm. All devices were successfully deployed. MAE occurred in 3 (4.0%) of 75 subjects at 9 months. Primary patency and freedom from CD-TVR at 9 months were both 95.8%. ABI improved from 0.67±0.14 at baseline to 0.94±0.14 and 0.96±0.16 at 30 days and 9-month follow-up, respectively (p<0.001 for both). There were no differences with respect to any of the analyzed patient characteristics, including gender. Conclusion: Nine-month results of the VISIBILITY Iliac stent study (ClinicalTrials.gov identifier NCT01402700) demonstrated safety and effectiveness for the treatment of atherosclerotic CIA and EIA lesions with the Visi-Pro stent across all treated cohorts. PMID:28351204

A Migrated Aortic Stent Graft Causing Erosive Spondylopathy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gestrich, Christopher, E-mail: christopher.gestrich@ukb.uni-bonn.de; Probst, Chris, E-mail: chris.probst@ukb.uni-bonn.de; Wilhelm, Kai, E-mail: kai.wilhelm@ek-bonn.de

We report about a patient presenting with back pain 4 months after an uneventful endovascular implantation of an aortic stent graft. Computed tomography scan revealed a migration of the stent with consecutive endoleakage, kink formation, and movement of the stent toward the spine, which caused destruction of the aortic wall as well as vertebral necrosis. Explantation of the stent and replacement of the native aorta relieved the patient of his symptoms.

A simplified in vivo approach for evaluating the bioabsorbable behavior of candidate stent materials.

PubMed

Pierson, Daniel; Edick, Jacob; Tauscher, Aaron; Pokorney, Ellen; Bowen, Patrick; Gelbaugh, Jesse; Stinson, Jon; Getty, Heather; Lee, Chee Huei; Drelich, Jaroslaw; Goldman, Jeremy

2012-01-01

Metal stents are commonly used to revascularize occluded arteries. A bioabsorbable metal stent that harmlessly erodes away over time may minimize the normal chronic risks associated with permanent implants. However, there is no simple, low-cost method of introducing candidate materials into the arterial environment. Here, we developed a novel experimental model where a biomaterial wire is implanted into a rat artery lumen (simulating bioabsorbable stent blood contact) or artery wall (simulating bioabsorbable stent matrix contact). We use this model to clarify the corrosion mechanism of iron (≥99.5 wt %), which is a candidate bioabsorbable stent material due to its biocompatibility and mechanical strength. We found that iron wire encapsulation within the arterial wall extracellular matrix resulted in substantial biocorrosion by 22 days, with a voluminous corrosion product retained within the vessel wall at 9 months. In contrast, the blood-contacting luminal implant experienced minimal biocorrosion at 9 months. The importance of arterial blood versus arterial wall contact for regulating biocorrosion was confirmed with magnesium wires. We found that magnesium was highly corroded when placed in the arterial wall but was not corroded when exposed to blood in the arterial lumen for 3 weeks. The results demonstrate the capability of the vascular implantation model to conduct rapid in vivo assessments of vascular biomaterial corrosion behavior and to predict long-term biocorrosion behavior from material analyses. The results also highlight the critical role of the arterial environment (blood vs. matrix contact) in directing the corrosion behavior of biodegradable metals. Copyright © 2011 Wiley Periodicals, Inc.

In-hospital management and outcome of patients on warfarin undergoing coronary stent implantation: results of the multicenter, prospective WARfarin and coronary STENTing (WAR-STENT) registry.

PubMed

Rubboli, Andrea; Sciahbasi, Alessandro; Briguori, Carlo; Saia, Francesco; Palmieri, Cataldo; Moroni, Luigi Andrea; Calabrò, Paolo; Leone, Antonio Maria; Franco, Nicoletta; Valgimigli, Marco; Varani, Elisabetta; Santi, Michela; Pasqualini, Paola; Capecchi, Alessandro; Piccalò, Giacomo; Margheri, Massimo; di Pasquale, Giuseppe; Galvani, Marcello; Bolognese, Leonardo; Gonzini, Lucio; Maggioni, Aldo Pietro

2013-04-01

The in-hospital management of patients on warfarin undergoing coronary stent implantation (PCI-S) is variable, and the in-hospital outcome incompletely defined. To determine the adherence to the current recommendations, and the incidence of adverse events, we carried out the prospective, multicenter, observational WARfarin and coronary STENTing (WAR-STENT) registry (ClinicalTrials.gov identifier NCT00722319). All consecutive patients on warfarin undergoing PCI-S at 37 Italian centers were enrolled and followed for 12 months. Outcome measures were: major adverse cardiovascular events (MACE), including cardiovascular death, non-fatal myocardial infarction, need for urgent revascularization, stroke, and venous thromboembolism, and major and minor bleeding. In this paper, we report the in-hospital findings. Out of the 411 patients enrolled, 92% were at non-low (ie, moderate or high) thromboembolic risk. The radial approach and bare-metal stents were used in 61% and 60% of cases, respectively. Drug-eluting stents were essentially reserved to patients with diabetes, which in turn, significantly predicted the implantation of drug-eluting stents (odds ratio [OR], 2.02; 95% confidence interval [CI], 1.29-3.17; P=.002). The in-hospital MACE and major bleeding rates were 2.7% and 2.1%, respectively. At discharge, triple therapy (TT) of warfarin, aspirin, and clopidogrel was prescribed to 76% of patients. Prescription of TT was significantly more frequent in the non-low thromboembolic risk group. Non-low thromboembolic risk, in turn, was a significant predictor of TT prescription (OR, 11.2; 95% CI, 4.83-26.3; P<.0001). In conclusion, real-world warfarin patients undergoing PCI-S are largely managed according to the current recommendations. As a consequence, the risk of in-hospital MACE and major bleedings appears limited and acceptable.

Demonstration of bacterial biofilms in culture-negative silicone stent and jones tube.

PubMed

Parsa, Kami; Schaudinn, Christoph; Gorur, Amita; Sedghizadeh, Parish P; Johnson, Thomas; Tse, David T; Costerton, John W

2010-01-01

To demonstrate the presence of bacterial biofilms on a dacryocystorhinostomy silicone stent and a Jones tube. One dacryocystorhinostomy silicone stent and one Jones tube were removed from 2 patients who presented with an infection of their respective nasolacrimal system. Cultures were obtained, and the implants were processed for scanning electron microscopy and confocal laser scanning microscopy, advanced microscopic methods that are applicable for detection of uncultivable biofilm organisms. Routine bacterial cultures revealed no growth, but bacterial biofilms on outer and inner surfaces of both implants were confirmed by advanced microscopic techniques. To the authors' knowledge, this is the first article that documents the presence of biofilms on a Crawford stent or a Jones tube on patients who presented with infections involving the nasolacrimal system. Although initial cultures revealed absence of any bacterial growth, confocal laser scanning microscopy and scanning electron microscopy documented bacterial colonization. Clinicians should consider the role of biofilms and the limitation of our standard culturing techniques while treating patients with device- or implant-related infections.

Comparison of early-phase arterial repair following cobalt-chrome everolimus-eluting stent and slow-release zotarolimus-eluting stent: an angioscopic study.

PubMed

Ishihara, Takayuki; Iida, Osamu; Fujita, Masashi; Masuda, Masaharu; Okamoto, Shin; Nanto, Kiyonori; Kanda, Takashi; Tsujimura, Takuya; Sunaga, Akihiro; Awata, Masaki; Nanto, Shinsuke; Uematsu, Masaaki

2018-04-01

Whether arterial repair following implantation of drug-eluting stents (DES) of the second generation differs among stent types remains unknown. We examined 41 DES placed in 28 patients (age 72 ± 7 years, male 89%) presenting with stable angina pectoris due to de novo lesions in native coronary arteries. Coronary angioscopy was performed 4 ± 1 months after stent implantation. Patients were divided into two groups based on the DES types: 22 cobalt-chrome everolimus-eluting stents (CoCr-EES) in 13 patients and 19 slow-release zotarolimus-eluting stents (R-ZES) in 15 patients. Neointimal coverage (NIC) was graded as: grade 0, stent struts exposed; grade 1, struts bulging into the lumen, although covered; grade 2, struts embedded in the neointima, but translucent; grade 3, struts fully embedded and invisible. NIC was defined as heterogeneous when the NIC grade variation was ≥1. Presence of thrombus was also investigated. Distribution of dominant NIC grade (CoCr-EES: grade 0, 9%; grade 1, 77%; grade 2, 9%; grade 3, 5%; R-ZES: grade 0, 16%; grade 1: 47%; grade 2, 37%; grade 3, 0%, P = 0.38) and heterogeneity of NIC (P = 0.43) were similar between CoCr-EES and R-ZES groups. Existence of thrombus was not significantly different in CoCr-EES and R-ZES (18 versus 42%, P = 0.17). Arterial repair occurred without significant differences between CoCr-EES and R-ZES 4 months after implantation.

Immediate, short‐, and long‐term changes in tracheal stent diameter, length, and positioning after placement in dogs with tracheal collapse syndrome

PubMed Central

Raske, Matthew; Berent, Allyson C.; McDougall, Renee; Lamb, Kenneth

2018-01-01

Background Intraluminal tracheal stenting is a minimally invasive procedure shown to have variable degrees of success in managing clinical signs associated with tracheal collapse syndrome (CTCS) in dogs. Objectives Identify immediate post‐stent changes in tracheal diameter, determine the extent of stent migration, and stent shortening after stent placement in the immediate‐, short‐, and long‐term periods, and evaluate inter‐observer reliability of radiographic measurements. Animals Fifty client‐owned dogs. Methods Retrospective study in which medical records were reviewed in dogs with CTCS treated with an intraluminal tracheal stent. Data collected included signalment, location, and type of collapse, stent diameter and length, and post‐stent placement radiographic follow‐up times. Radiographs were used to obtain pre‐stent tracheal measurements and post‐stent placement measurements. Results Immediate mean percentage change was 5.14%, 5.49%, and 21.64% for cervical, thoracic inlet, and intra‐thoracic tracheal diameters, respectively. Ultimate mean follow‐up time was 446 days, with mean percentage change of 2.55%, 15.09%, and 8.65% for cervical, thoracic inlet, and intra‐thoracic tracheal diameters, respectively. Initial mean stent length was 26.72% higher than nominal length and ultimate long‐term tracheal mean stent shortening was only 9.90%. No significant stent migration was identified in the immediate, short‐, or long‐term periods. Good inter‐observer agreement of radiographic measurements was found among observers of variable experience level. Conclusions and Clinical Importance Use of an intraluminal tracheal stent for CTCS is associated with minimal stent shortening with no clinically relevant stent migration after fluoroscopic placement. Precise stent sizing and placement techniques likely play important roles in avoiding these reported complications. PMID:29460368

Immediate, short-, and long-term changes in tracheal stent diameter, length, and positioning after placement in dogs with tracheal collapse syndrome.

PubMed

Raske, Matthew; Weisse, Chick; Berent, Allyson C; McDougall, Renee; Lamb, Kenneth

2018-03-01

Intraluminal tracheal stenting is a minimally invasive procedure shown to have variable degrees of success in managing clinical signs associated with tracheal collapse syndrome (CTCS) in dogs. Identify immediate post-stent changes in tracheal diameter, determine the extent of stent migration, and stent shortening after stent placement in the immediate-, short-, and long-term periods, and evaluate inter-observer reliability of radiographic measurements. Fifty client-owned dogs. Retrospective study in which medical records were reviewed in dogs with CTCS treated with an intraluminal tracheal stent. Data collected included signalment, location, and type of collapse, stent diameter and length, and post-stent placement radiographic follow-up times. Radiographs were used to obtain pre-stent tracheal measurements and post-stent placement measurements. Immediate mean percentage change was 5.14%, 5.49%, and 21.64% for cervical, thoracic inlet, and intra-thoracic tracheal diameters, respectively. Ultimate mean follow-up time was 446 days, with mean percentage change of 2.55%, 15.09%, and 8.65% for cervical, thoracic inlet, and intra-thoracic tracheal diameters, respectively. Initial mean stent length was 26.72% higher than nominal length and ultimate long-term tracheal mean stent shortening was only 9.90%. No significant stent migration was identified in the immediate, short-, or long-term periods. Good inter-observer agreement of radiographic measurements was found among observers of variable experience level. Use of an intraluminal tracheal stent for CTCS is associated with minimal stent shortening with no clinically relevant stent migration after fluoroscopic placement. Precise stent sizing and placement techniques likely play important roles in avoiding these reported complications. Copyright © 2018 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.

Peri-stent aneurysm formation following a stent implant for stenotic intracranial vertebral artery dissection: a technical report of two cases successfully treated with coil embolization.

PubMed

Ishimaru, Hideki; Nakashima, Kazuaki; Takahata, Hideaki; Matsuoka, Yohjiro

2013-02-01

Although stenting for stenotic vertebral artery dissection (VAD) improves compromised blood flow, subsequent peri-stent aneurysm (PSA) formation is not well-known. We report two cases with PSA successfully treated with coil embolization. Three patients with stenotic intracranial VAD underwent endovascular angioplasty at our institution because they had acute infarction in posterior circulation territory and clinical evidence of hemodynamic insufficiency. In two of three patients balloon angioplasty at first session failed to relieve the stenosis, and a coronary stent was implanted. Angiography immediately after stenting showed no abnormality in case 1 and minimal slit-like projection at proximal portion of the stent in case 2. Angiography obtained 16 months after the stenting revealed PSA in case 1. In case 2, angiography performed 3 months later showed that the projection at proximal portion enlarged and formed an aneurysm outside the stent. Because follow-up angiographies showed growth of the aneurysm in both cases, endovascular aneurysmal embolization was performed. We advanced a microcatheter into the aneurysm through the strut of existing stent and delivered detachable coils into the aneurysm lumen successfully in both cases. The post-procedural course was uneventful, and complete obliteration of aneurysm was confirmed on angiography in both cases. Stenting for stenotic intracranial VAD may result in delayed PSA; therefore, follow-up angiographies would be necessary after stenting for stenotic intracranial arterial dissection. Coil embolization through the stent strut would be a solution for enlarging PSA.

Clinical feasibility of a new through-the-scope fully covered esophageal self-expandable metallic stent: an in vivo animal study.

PubMed

Cheon, Young Koog; Lee, Tae Yoon; Sung, In Kyung; Shim, Chan Sup

2014-01-01

Most delivery devices used for esophageal stents for obstructing esophageal cancer have a diameter of 5-8 mm, a size that is too large to pass through the endoscopic working channel. The conventional esophageal stent requires multiple endoscopic procedures for implantation. The purpose of the present study was to evaluate the clinical feasibility of a newly developed fully covered, self-expanding, through-the-scope (TTS) esophageal stent in a porcine model. Eight mini pigs were used. Each animal underwent placement of a fully covered TTS stent (Hanarostent® Esophagus TTS) and the upper part of the stent was fixed by suturing with nylon. Fluoroscopy was carried out every week to assess migration of the stent. Follow-up endoscopy was done every month for 3 months to evaluate the status of the membrane, stent mesh, grade of tissue hyperplasia, and mucosal changes at both ends of the stent. All stents were successfully and easily deployed, and were placed without any distortion in the stent or without rupture of the membrane. In two cases, stent migration was observed after 8 weeks. No case of membrane disruption, stent mesh disruption or tissue hyperplasia at either end of the stent was found at the completion of the study. Our findings indicate that the new fully covered self-expanding TTS esophageal stent is easy and simple to implant, and no significant distortion of mesh or disruption of membrane was observed. © 2013 The Authors. Digestive Endoscopy © 2013 Japan Gastroenterological Endoscopy Society.

In vivo response of AZ31 alloy as biliary stents: a 6 months evaluation in rabbits

PubMed Central

Liu, Yang; Zheng, Shengmin; Li, Nan; Guo, Huahu; Zheng, Yufeng; Peng, Jirun

2017-01-01

Mg-based metallic materials have been making continuing progress as vascular stents. However, the research of Mg-based materials as non-vascular stents is still at its primary stage. AZ31 stents hereby were implanted into the common bile duct of rabbits for 6 months. The results revealed an existence of 93.82 ± 1.36% and 30.89 ± 2.46% of the original volume after 1 and 3 month, respectively. Whole blood tests indicated an inflammation decreasing to normal level after 3 month implantation. A benign host response was observed via H&E staining. Nonuniform corrosion at the two ends of the stents was observed and considered the results of flow or local inflammation. Moreover, the application of Mg-based materials for different stenting treatment were reviewed and compared. Esophagus was hypothesized most destructive, whilst blood vessel and bile duct considered similar and less destructive. Trachea and nasal cavity were thought to be mildest. PMID:28084306

Current State of Bioabsorbable Polymer-Coated Drug-Eluting Stents

PubMed Central

Akinapelli, Abhilash; Chen, Jack P.; Roy, Kristine; Donnelly, Joseph; Dawkins, Keith; Huibregtse, Barbara; Hou, Dongming

2017-01-01

Drug-eluting stents (DES) have been shown to significantly reduce clinical and angiograph-ic restenosis compared to bare metal stents (BMS). The polymer coatings on DES elute antiproliferative drugs to inhibit intimal proliferation and prevent restenosis after stent implantation. Permanent poly-mers which do not degrade in vivo may increase the likelihood of stent-related delayed arterial healing or polymer hypersensitivity. In turn, these limitations may contribute to an increased risk of late clinical events. Intuitively, a polymer which degrades after completion of drug release, leaving an inert metal scaffold in place, may improve arterial healing by removing a chronic source of inflammation, neoath-erosclerosis, and/or late thrombosis. In this way, a biodegradable polymer may reduce late ischemic events. Additionally, improved healing after stent implantation could reduce the requirement for long-term dual antiplatelet therapy and the associated risk of bleeding and cost. This review will focus on bioabsorbable polymer-coated DES currently being evaluated in clinical trials.

In vivo response of AZ31 alloy as biliary stents: a 6 months evaluation in rabbits

NASA Astrophysics Data System (ADS)

Liu, Yang; Zheng, Shengmin; Li, Nan; Guo, Huahu; Zheng, Yufeng; Peng, Jirun

2017-01-01

Mg-based metallic materials have been making continuing progress as vascular stents. However, the research of Mg-based materials as non-vascular stents is still at its primary stage. AZ31 stents hereby were implanted into the common bile duct of rabbits for 6 months. The results revealed an existence of 93.82 ± 1.36% and 30.89 ± 2.46% of the original volume after 1 and 3 month, respectively. Whole blood tests indicated an inflammation decreasing to normal level after 3 month implantation. A benign host response was observed via H&E staining. Nonuniform corrosion at the two ends of the stents was observed and considered the results of flow or local inflammation. Moreover, the application of Mg-based materials for different stenting treatment were reviewed and compared. Esophagus was hypothesized most destructive, whilst blood vessel and bile duct considered similar and less destructive. Trachea and nasal cavity were thought to be mildest.

Meta-analysis of long-term outcomes of drug-eluting stent implantations for chronic total coronary occlusions.

PubMed

Ma, Jian; Yang, Weiwei; Singh, Manpreet; Peng, Tianqing; Fang, Ningyuan; Wei, Meng

2011-01-01

In the treatment of chronic total occlusions (CTOs), some uncertainty exists regarding the effect of drug-eluting stents (DESs) compared with the effects of bare mental stents (BMSs). We reviewed outcomes of DES vs. BMS implantation for CTO lesions, to evaluate the risk-benefit ratio of DES implantation. Relevant studies of long-term clinical outcomes or angiographic outcomes of both BMS and DES implantation were examined. The primary endpoint comprised major adverse cardiovascular events (MACEs), including all-cause deaths, myocardial infarctions (MIs), and target lesion revascularizations (TLRs). A fixed-effect model and random-effect model were used to analyze the pooling results. Ten studies were included according to the selection criteria. Eight were nonrandomized controlled trials, and two consisted of a randomized controlled comparison between DES and BMS implantation. No significant difference was evident for in-hospital MACE rates between the two groups (odds ratio [OR], 1.07; 95% confidence interval [CI], .53 to 2.13), but the long-term MACE rates in the DES group were significantly lower than in the BMS group (OR, .22; 95% CI, .13 to .38; P < .00001). The rates of stent restenosis and reocclusions were also significantly lower in the DES group (OR, .14; 95% CI, .09 to .20; and OR, .23; 95% CI, .12 to .41, respectively). Implantation of the DES improves long-term angiographic and clinical outcomes compared with BMS in the treatment of CTO lesions. Copyright © 2011 Elsevier Inc. All rights reserved.

Intra-stent tissue evaluation within bare metal and drug-eluting stents > 3 years since implantation in patients with mild to moderate neointimal proliferation using optical coherence tomography and virtual histology intravascular ultrasound.

PubMed

Kitabata, Hironori; Loh, Joshua P; Pendyala, Lakshmana K; Omar, Alfazir; Ota, Hideaki; Minha, Sa'ar; Magalhaes, Marco A; Torguson, Rebecca; Chen, Fang; Satler, Lowell F; Pichard, Augusto D; Waksman, Ron

2014-04-01

We aimed to compare neointimal tissue characteristics between bare-metal stents (BMS) and drug-eluting stents (DES) at long-term follow-up using optical coherence tomography (OCT) and virtual histology intravascular ultrasound (VH-IVUS). Neoatherosclerosis in neointima has been reported in BMS and in DES. Thirty patients with 36 stented lesions [BMS (n=17) or DES (n=19)] >3years after implantation were prospectively enrolled. OCT and VH-IVUS were performed and analyzed independently. Stents with ≥70% diameter stenosis were excluded. The median duration from implantation was 126.0months in the BMS group and 60.0months in the DES group (p <0.001). Lipid-laden intima (58.8% vs. 42.1%, p=0.317), thrombus (17.6% vs. 5.3%, p=0.326), and calcification (35.3% vs. 26.3%, p=0.559) did not show significant differences between BMS and DES. When divided into 3 time periods, the cumulative incidence of lipid-laden neointima from >3years to <9years was similar between BMS and DES (42.9% vs. 42.1%, p=1.000). Furthermore, it continued to gradually increase over time in both groups. OCT-derived thin-cap fibroatheroma (TCFA) was observed in 17.6% of BMS- and 5.3% of DES-treated lesions (p=0.326). No stents had evidence of intimal disruption. The percentage volume of necrotic core (16.1% [9.7, 20.3] vs. 9.7% [7.0, 16.5], p=0.062) and dense calcium (9.5% [3.8, 13.6] vs. 2.7% [0.4, 4.9], p=0.080) in neointima tended to be greater in BMS-treated lesions. Intra-stent VH-TCFA (BMS vs. DES 45.5% vs. 18.2%, p=0.361) did not differ significantly. At long-term follow-up beyond 3 years after implantation, the intra-stent neointimal tissue characteristics appeared similar for both BMS and DES. Copyright © 2014 Elsevier Inc. All rights reserved.

Outcome and management of pacemaker-induced superior vena cava syndrome.

PubMed

Fu, Hai-Xia; Huang, Xin-Miao; Zhong, Li; Osborn, Michael J; Bjarnason, Haraldur; Mulpuru, Siva; Zhao, Xian-Xian; Friedman, Paul A; Cha, Yong-Mei

2014-11-01

We aimed to determine the long-term outcomes of percutaneous lead extraction and stent placement in patients with pacemaker-induced superior vena cava (SVC) syndrome. The study retrospectively screened patients who underwent lead extraction followed by central vein stent implantation at Mayo Clinic (Rochester, MN, USA), from January 2005 to December 2012, to identify the patients with pacemaker-induced SVC syndrome. Demographic, clinical, and follow-up characteristics of those patients were collected from electronic medical records. Six cases were identified. The mean (standard deviation) age was 56 (15) years (male, 67%). All patients had permanent dual-chamber pacemakers, with a mean 11-year history of pacemaker placement. The entire device system was explanted in five patients; one patient had a 21-year-old pacemaker lead that could not be removed. Eight stents were implanted in six patients: five patients had one stent, one patient had three. A new pacemaker system was reimplanted through the stented vein in five patients. Technical success was achieved in all patients, without any complication. Symptoms rapidly resolved in all patients after stent deployment. The mean follow-up duration was 48 months (range, 10-100 months). Three patients remained symptom free. Reintervention with percutaneous balloon venoplasty was successful in three patients with symptom recurrence. Percutaneous stent implantation after lead removal followed by reimplantation of leads is a feasible alternative therapy for pacemaker-induced SVC syndrome, although some cases may require repeat intervention. ©2014 Wiley Periodicals, Inc.

Adjunctive stent use during endovascular intervention to the femoropopliteal artery with drug coated balloons: Insights from the XLPAD registry.

PubMed

Kokkinidis, Damianos G; Jeon-Slaughter, Haekyung; Khalili, Houman; Brilakis, Emmanouil S; Shammas, Nicolas W; Banerjee, Subhash; Armstrong, Ehrin J

2018-06-01

With growing use of drug-coated balloons (DCB) for femoropopliteal (FP) artery interventions, there is limited information on rates of real-world adjunctive stent use and its association with short and long-term outcomes. We report on 225 DCB treated FP lesions in 224 patients from the Excellence in Peripheral Artery Disease (XLPAD) registry (NCT01904851) between 2014 and 2016. Cochran-Mantel-Haenszel and Wilcoxon rank sum statistics were used to compare stented (planned or 'bail-out') versus non-stented DCB treated lesions. Stents were implanted in 31% of FP DCB interventions. Among the 70 stents implanted, 46% were for 'bail-out' indications and 54% were planned. Lesions treated with stents were longer (mean 150 mm vs 100 mm; p < 0.001) and less likely to be in-stent restenosis lesions (10% vs 28%; p=0.003). Stenting was significantly more frequent in complex FP lesions, including chronic total occlusions (66% vs 34%; p < 0.001). For bail-out stenting, interwoven nitinol stents were the most common type (50%) followed by drug-eluting stents (34%) and bare-metal stents (22%). There were no differences in peri-procedural complication rates or 12-month target limb revascularization rates (18.6% vs 11.6%; p=0.162) or 12-month amputation rates (11.4% vs 11%; p=0.92) between lesions where adjunctive stenting was used versus lesions without adjunctive stenting, respectively. In conclusion, in a contemporary 'real-world' adjudicated multicenter US registry, adjunctive stenting was necessary in nearly a third of the lesions, primarily for the treatment of more complex FP lesions, with similar short and intermediate-term clinical outcomes compared with non-stented lesions.

Surgical stent planning: simulation parameter study for models based on DICOM standards.

PubMed

Scherer, S; Treichel, T; Ritter, N; Triebel, G; Drossel, W G; Burgert, O

2011-05-01

Endovascular Aneurysm Repair (EVAR) can be facilitated by a realistic simulation model of stent-vessel-interaction. Therefore, numerical feasibility and integrability in the clinical environment was evaluated. The finite element method was used to determine necessary simulation parameters for stent-vessel-interaction in EVAR. Input variables and result data of the simulation model were examined for their standardization using DICOM supplements. The study identified four essential parameters for the stent-vessel simulation: blood pressure, intima constitution, plaque occurrence and the material properties of vessel and plaque. Output quantities such as radial force of the stent and contact pressure between stent/vessel can help the surgeon to evaluate implant fixation and sealing. The model geometry can be saved with DICOM "Surface Segmentation" objects and the upcoming "Implant Templates" supplement. Simulation results can be stored using the "Structured Report". A standards-based general simulation model for optimizing stent-graft selection may be feasible. At present, there are limitations due to specification of individual vessel material parameters and for simulating the proximal fixation of stent-grafts with hooks. Simulation data with clinical relevance for documentation and presentation can be stored using existing or new DICOM extensions.

Use of a biodegradable, oversized stent in a child with tracheomalacia secondary to vascular external compression.

PubMed

Di Dedda, Giovanni; Mirabile, Cristian

2017-01-01

We describe the implantation of an absorbable, custom-made stent of polydioxanone to treat tracheomalacia in a 5-month-old patient with extrinsic compression by a double aortic arch. The use of an absorbable, oversized stent treated the tracheal collapse caused by vascular compression, avoided removal procedures, and allowed the infant's growth. The use of an oversized stent prevented stent migration and gave minimal problems of granulation.

Covered stent to exclude intravascular thrombus.

PubMed

Liistro, Francesco; Stankovic, Goran; Di Mario, Carlo; Montorfano, Matteo; Briguori, Carlo; Colombo, Antonio

2002-04-01

To describe the utility of stent-graft implantation to avoid distal embolization from a large thrombus-containing lesion. A 67-year-old man was evaluated for recent onset of disabling left leg claudication. Angiography disclosed a mobile lobular mass occluding the left common iliac artery; irregular staining suggested an atherothrombotic lesion. Through a percutaneous ipsilateral access and an 8-F sheath, a balloon-expandable Jostent peripheral stent-graft was positioned with the distal edge immediately proximal to the internal iliac artery ostium. A prominent "waist" at the center of the balloon confirmed entrapment of the thrombotic mass. Completion angiography showed an optimal result with no residual stenosis or evidence of distal embolization. At 6-month follow-up, the patient was asymptomatic with angiographically documented luminal patency and no evidence of in-stent stenosis. Stent-graft implantation appears a viable treatment alternative for thrombus-containing lesions, particularly when the thrombotic material is localized or is in a large vessel.

Fatigue and In Vivo Validation of a Peritoneum-Lined Self-Expanding Nitinol Stent-Graft

PubMed Central

Bastijanic, Jennifer M.; Etscheidt, Jordan; Sattiraju, Mallika; Bonsignore, Craig; Kopchok, George; White, Rodney; Sarac, Timur P.

2014-01-01

Purpose To assess the fatigue and in vivo performance of a new stent-graft incorporating bovine peritoneum lining that is designed for application in peripheral vascular occlusive disease. Methods Bovine peritoneum-lined stent-grafts were subjected to accelerated in vitro pulsatile fatigue and axial/torsional fatigue testing designed to simulate 10 years of physiological strain on the devices. At specified times the devices were evaluated for stent fracture, suture failure, or tissue tearing. Seven dogs underwent bilateral common iliac artery (CIA) balloon angioplasty injury with unilateral placement of the peritoneum-lined stent-graft. Angiography and intravascular ultrasound were performed prior to treatment, after treatment, and prior to sacrifice at 30 days. Vessels were perfusion fixed and histologically evaluated at 5 regions: above stent, proximal stent, mid stent, distal stent, and below stent. Results No evidence of stent, suture, or tissue failure was present during or after pulsatile and axial/torsional fatigue testing. At 30±0.3 days after implantation, all vessels were patent. The average lumen area at explantation across stented vessels was 25.45 mm2. Lumen areas tended to be reduced above (23.57 mm2) and below (24.17 mm2) the stent. Lumen areas were consistent across stented regions at explantation (proximal stent 27.80 mm2, mid stent 25.88 mm2, and distal stent 25.81 mm2). The mean neointimal area in peritoneum-lined stents was 2.02±1.52 mm2, with a neointima:media ratio of 1.03±0.50. These values were significantly lower in the above and below stent areas than in the stented regions, but there was no difference in either measure within the proximal, mid, or distal stent. Conclusion The custom-designed peritoneum-lined stent-graft is promising for clinical peripheral applications due to its ability to resist relevant long-term physiological stresses and outstanding short-term patency rates in canine implantations. PMID:25290804

Biodegradable Metals for Cardiovascular Stent Application: Interests and New Opportunities

PubMed Central

Moravej, Maryam; Mantovani, Diego

2011-01-01

During the last decade, biodegradable metallic stents have been developed and investigated as alternatives for the currently-used permanent cardiovascular stents. Degradable metallic materials could potentially replace corrosion-resistant metals currently used for stent application as it has been shown that the role of stenting is temporary and limited to a period of 6–12 months after implantation during which arterial remodeling and healing occur. Although corrosion is generally considered as a failure in metallurgy, the corrodibility of certain metals can be an advantage for their application as degradable implants. The candidate materials for such application should have mechanical properties ideally close to those of 316L stainless steel which is the gold standard material for stent application in order to provide mechanical support to diseased arteries. Non-toxicity of the metal itself and its degradation products is another requirement as the material is absorbed by blood and cells. Based on the mentioned requirements, iron-based and magnesium-based alloys have been the investigated candidates for biodegradable stents. This article reviews the recent developments in the design and evaluation of metallic materials for biodegradable stents. It also introduces the new metallurgical processes which could be applied for the production of metallic biodegradable stents and their effect on the properties of the produced metals. PMID:21845076

Impact of stent strut design in metallic stents and biodegradable scaffolds.

PubMed

Foin, Nicolas; Lee, Renick D; Torii, Ryo; Guitierrez-Chico, Juan Luis; Mattesini, Alessio; Nijjer, Sukhjinder; Sen, Sayan; Petraco, Ricardo; Davies, Justin E; Di Mario, Carlo; Joner, Michael; Virmani, Renu; Wong, Philip

2014-12-20

Advances in the understanding of healing mechanisms after stent implantation have led to the recognition of stent strut thickness as an essential factor affecting re-endothelialization and overall long term vessel healing response after Percutaneous Coronary Interventions (PCI). Emergence of Drug-eluting stents (DESs) with anti-proliferative coating has contributed to reducing the incidence of restenosis and Target Lesion Revascularization (TVR), while progress and innovations in stent materials have in the meantime facilitated the design of newer platforms with more conformability and thinner struts, producing lesser injury and improving integration into the vessel wall. Recent advances in biodegradable metal and polymer materials now also allow for the design of fully biodegradable platforms, which are aimed at scaffolding the vessel only temporarily to prevent recoil and constrictive remodeling of the vessel during the initial period required, and are then progressively resorbed thereby avoiding the drawback of leaving an unnecessary implant permanently in the vessel. The aim of this article is to review recent evolution in stent material and stent strut design while understanding their impact on PCI outcomes. The article describes the different metallic alloys and biodegradable material properties and how these have impacted the evolution of stent strut thickness and ultimately outcomes in patients. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Magnetizable stent-grafts enable endothelial cell capture

NASA Astrophysics Data System (ADS)

Tefft, Brandon J.; Uthamaraj, Susheil; Harburn, J. Jonathan; Hlinomaz, Ota; Lerman, Amir; Dragomir-Daescu, Dan; Sandhu, Gurpreet S.

2017-04-01

Emerging nanotechnologies have enabled the use of magnetic forces to guide the movement of magnetically-labeled cells, drugs, and other therapeutic agents. Endothelial cells labeled with superparamagnetic iron oxide nanoparticles (SPION) have previously been captured on the surface of magnetizable 2205 duplex stainless steel stents in a porcine coronary implantation model. Recently, we have coated these stents with electrospun polyurethane nanofibers to fabricate prototype stent-grafts. Facilitated endothelialization may help improve the healing of arteries treated with stent-grafts, reduce the risk of thrombosis and restenosis, and enable small-caliber applications. When placed in a SPION-labeled endothelial cell suspension in the presence of an external magnetic field, magnetized stent-grafts successfully captured cells to the surface regions adjacent to the stent struts. Implantation within the coronary circulation of pigs (n=13) followed immediately by SPION-labeled autologous endothelial cell delivery resulted in widely patent devices with a thin, uniform neointima and no signs of thrombosis or inflammation at 7 days. Furthermore, the magnetized stent-grafts successfully captured and retained SPION-labeled endothelial cells to select regions adjacent to stent struts and between stent struts, whereas the non-magnetized control stent-grafts did not. Early results with these prototype devices are encouraging and further refinements will be necessary in order to achieve more uniform cell capture and complete endothelialization. Once optimized, this approach may lead to more rapid and complete healing of vascular stent-grafts with a concomitant improvement in long-term device performance.

Magnetizable stent-grafts enable endothelial cell capture.

PubMed

Tefft, Brandon J; Uthamaraj, Susheil; Harburn, J Jonathan; Hlinomaz, Ota; Lerman, Amir; Dragomir-Daescu, Dan; Sandhu, Gurpreet S

2017-04-01

Emerging nanotechnologies have enabled the use of magnetic forces to guide the movement of magnetically-labeled cells, drugs, and other therapeutic agents. Endothelial cells labeled with superparamagnetic iron oxide nanoparticles (SPION) have previously been captured on the surface of magnetizable 2205 duplex stainless steel stents in a porcine coronary implantation model. Recently, we have coated these stents with electrospun polyurethane nanofibers to fabricate prototype stent-grafts. Facilitated endothelialization may help improve the healing of arteries treated with stent-grafts, reduce the risk of thrombosis and restenosis, and enable small-caliber applications. When placed in a SPION-labeled endothelial cell suspension in the presence of an external magnetic field, magnetized stent-grafts successfully captured cells to the surface regions adjacent to the stent struts. Implantation within the coronary circulation of pigs (n=13) followed immediately by SPION-labeled autologous endothelial cell delivery resulted in widely patent devices with a thin, uniform neointima and no signs of thrombosis or inflammation at 7 days. Furthermore, the magnetized stent-grafts successfully captured and retained SPION-labeled endothelial cells to select regions adjacent to stent struts and between stent struts, whereas the non-magnetized control stent-grafts did not. Early results with these prototype devices are encouraging and further refinements will be necessary in order to achieve more uniform cell capture and complete endothelialization. Once optimized, this approach may lead to more rapid and complete healing of vascular stent-grafts with a concomitant improvement in long-term device performance.

Quantitative optical coherence tomography analysis for late in-stent restenotic lesions.

PubMed

Fu, Qiang; Suzuki, Nobuaki; Kozuma, Ken; Miyagawa, Mutsuki; Nomura, Takahiro; Kawashima, Hideyuki; Shiratori, Yoshitaka; Ishikawa, Shuichi; Kyono, Hiroyuki; Isshiki, Takaaki

2015-01-01

Coronary optical coherence tomography (OCT) has the potential to identify in-stent neoatherosclerosis, which is a possible risk factor for late acute coronary events after drug-eluting stent implantation. The purpose of this study was to investigate differences between mid-term and late in-stent restenosis after stent implantation by quantitative and semiautomated tissue property analysis using OCT. In total, 1063 OCT image frames of 16 lesions in 15 patients were analyzed. This included 346 frames of 6 lesions in late in-stent restenosis, which was defined as restenosis that was not detected at 6 to 12 months but ≥ 12 months after follow-up coronary angiography. Signal attenuation was circumferentially analyzed using a dedicated semiautomated software. Attenuation was assessed along 200 lines delineated radially for analysis of the in-stent restenotic lesions (between the lumen and stent contours). All lines were anchored by the image wire to avoid artifacts resulting from wire location. Stronger signal attenuation at the frame level (2.46 ± 0.78 versus 1.47 ± 0.32, P < 0.001) and higher maximum signal intensity at the lesion level (9.19 ± 0.19 versus 8.84 ± 0.32, P = 0.018) were observed in late in-stent restenotic lesions than in mid-term in-stent restenotic lesions. OCT demonstrated stronger signal attenuation and higher maximum signal intensity in late in-stent restenotic lesions than in mid-term in-stent restenotic lesions, indicating the possibility of neoatherosclerosis.

Intraocular Pressure and Retinal Nerve Fibre Layer Thickness Changes After Carotid Artery Stenting.

PubMed

Biberoğlu, Esra; Eraslan, Muhsin; Baltacıoğlu, Feyyaz; Midi, İpek

2017-08-01

The aim of this study was to evaluate intraocular pressure (IOP) and retinal nerve fiber layer (RNFL) changes in patients with carotid artery stenosis (CAS) after carotid artery stenting. This study was conducted as a cross-sectional, non-randomised clinical case series. Fifteen male patients (mean age: 63.6±9.1) with CAS and more than 70% carotid artery narrowing were included. All of the patients were followed in the department of neurology and were operated in the interventional radiology division. Eighteen healthy male subjects (mean age: 63.7±5.3) were included in the control group. All of the healthy subjects had a detailed ophthalmological examination and subjects with any chronic eye disease were excluded from the study. All of the participants had a detailed ophthalmological examination including tonometry using Goldmann applanation tonometry and RNFL analysis using optical coherence tomography (RTVue-100 5.1). There were no ocular ischemic symptoms in any of the participants. The mean IOP value was 15.1±2.1 mmHg in the control group and 16.6±2.4 mmHg before stent implantation, 16.4±2.2 mmHg at 1 week after implantation, 16.6±2.5 mmHg at 1 month after implantation, and 16.7±2.9 mmHg at 3 months after implantation in the CAS group. Mean RNFL thickness was 105±6 µm in the control group; in the CAS group, mean RNFL thickness values were 98±27 µm before stent implantation and 103±11 µm, 101±10 µm, and 101±11 µm at 1 week, 1 month, and 3 months after stenting. There were no significant differences between the CAS group and control group regarding IOP and RNFL thickness values (p>0.05). IOP and RNFL thickness also did not show any statistically significant changes from preoperative measurements in 3 months postoperative follow-up in the CAS group (p>0.05). IOP and RNFL thickness remained unchanged after carotid stent implantation in carotid artery stenosis patients with no signs of ocular ischemic syndrome.

Intraocular Pressure and Retinal Nerve Fibre Layer Thickness Changes After Carotid Artery Stenting

PubMed Central

Biberoğlu, Esra; Eraslan, Muhsin; Baltacıoğlu, Feyyaz; Midi, İpek

2017-01-01

Objectives: The aim of this study was to evaluate intraocular pressure (IOP) and retinal nerve fiber layer (RNFL) changes in patients with carotid artery stenosis (CAS) after carotid artery stenting. Materials and Methods: This study was conducted as a cross-sectional, non-randomised clinical case series. Fifteen male patients (mean age: 63.6±9.1) with CAS and more than 70% carotid artery narrowing were included. All of the patients were followed in the department of neurology and were operated in the interventional radiology division. Eighteen healthy male subjects (mean age: 63.7±5.3) were included in the control group. All of the healthy subjects had a detailed ophthalmological examination and subjects with any chronic eye disease were excluded from the study. All of the participants had a detailed ophthalmological examination including tonometry using Goldmann applanation tonometry and RNFL analysis using optical coherence tomography (RTVue-100 5.1). Results: There were no ocular ischemic symptoms in any of the participants. The mean IOP value was 15.1±2.1 mmHg in the control group and 16.6±2.4 mmHg before stent implantation, 16.4±2.2 mmHg at 1 week after implantation, 16.6±2.5 mmHg at 1 month after implantation, and 16.7±2.9 mmHg at 3 months after implantation in the CAS group. Mean RNFL thickness was 105±6 µm in the control group; in the CAS group, mean RNFL thickness values were 98±27 µm before stent implantation and 103±11 µm, 101±10 µm, and 101±11 µm at 1 week, 1 month, and 3 months after stenting. There were no significant differences between the CAS group and control group regarding IOP and RNFL thickness values (p>0.05). IOP and RNFL thickness also did not show any statistically significant changes from preoperative measurements in 3 months postoperative follow-up in the CAS group (p>0.05). Conclusion: IOP and RNFL thickness remained unchanged after carotid stent implantation in carotid artery stenosis patients with no signs of ocular ischemic syndrome. PMID:28845322

When Not to Go SOLO? Contraindications Based on Implant Experience.

PubMed

Wollersheim, Laurens W; Li, Wilson W; Kaya, Abdullah; van Boven, Wim J; van der Meulen, Jan; de Mol, Bas A

2016-11-01

Because of the design and specific implantation technique of the stentless Freedom SOLO bioprosthesis, patient selection is crucial. The aim of the study was to discuss the contraindications to this prosthesis based on the authors' implant experience. Between April 2005 and February 2015, one surgeon at the authors' center performed 292 aortic valve replacements using a bioprosthesis, with the initial intention of implanting a SOLO valve in every patient. A search was conducted for all of these patients and data collected on whether a SOLO valve was used, or not. A SOLO valve was implanted in 238 patients (82%), and a stented bioprosthesis in 54 (18%). The predominant reasons not to implant a SOLO valve were asymmetric commissures (26%) and a large aortic annulus (24%). Only one patient had structural valve deterioration, and none of the patients had to undergo reoperation because of aortic valve insufficiency or paravalvular leakage. Asymmetric commissures, large aortic annulus (>27 mm), calcified aortic sinuses, dilated sinotubular junction, aberrant location of coronary ostia and whenever the stent of a stented bioprosthesis is useful, were contraindications to implant a SOLO valve. When these contraindications were taken into account, a very good durability could be achieved with the SOLO valve during mid-term follow up.

Acute stent thrombosis after a "stroll for fresh air". A case of the smoking gun.

PubMed

Gotsman, I; Helman, Y; Planer, D

2013-02-01

We present a case of a patient who underwent a percutaneous coronary intervention and excused himself for some "fresh air". He subsequently developed acute stent thrombosis. We discuss the contribution of acute cigarette smoking to this serious complication after stent implantation.

[Transjugular intrahepatic portosystemic shunting with covered stents in children: a preliminary study of safety and patency].

PubMed

Zurera, L J; Espejo, J J; Canis, M; Bueno, A; Vicente, J; Gilbert, J J

2014-01-01

To retrospectively analyze the safety and efficacy of transjugular intrahepatic portosystemic shunting (TIPS) using covered stents in children. We present 6 children (mean age, 10.6 years; mean weight, 33.5kg) who underwent TIPS with 8mm diameter Viatorr(®) covered stents for acute (n=4) or recurrent (n=2) upper digestive bleeding that could not be controlled by endoscopic measures. Five of the children had cirrhosis and the other had portal vein thrombosis with cavernous transformation. We analyzed the relapse of upper digestive bleeding, the complications that appeared, and the patency of the TIPS shunt on sequential Doppler ultrasonography or until transplantation. A single stent was implanted in a single session in each child; none of the children died. The mean transhepatic gradient decreased from 16mmHg (range: 12-21mmHg) before the procedure to 9mmHg (range: 1-15mmHg) after TIPS. One patient developed mild encephalopathy, and the girl who had portal vein thrombosis with cavernous transformation developed an acute occlusion of the TIPS that resolved after the implantation of a coaxial stent. Three children received transplants (7, 9, and 10 months after the procedure, respectively), and the patency of the TIPS was confirmed at transplantation. In the three remaining children, patency was confirmed with Doppler ultrasonography 1, 3, and 5 months after implantation. None of the children had new episodes of upper digestive bleeding during follow-up after implantation (mean: 8.1 months). Our results indicate that TIPS with 8mm diameter Viatorr(®) covered stents can be safe and efficacious for the treatment of upper digestive bleeding due to gastroesophageal varices in cirrhotic children; our findings need to be corroborated in larger series. Copyright © 2011 SERAM. Published by Elsevier Espana. All rights reserved.

Incidence and Clinical Outcomes of Stent Fractures on the Basis of 6,555 Patients and 16,482 Drug-Eluting Stents From 4 Centers.

PubMed

Kan, Jing; Ge, Zhen; Zhang, Jun-Jie; Liu, Zhi-Zhong; Tian, Nai-Liang; Ye, Fei; Li, Sui-Ji; Qian, Xue-Song; Yang, Song; Chen, Meng-Xuan; Rab, Tanveer; Chen, Shao-Liang

2016-06-13

The present study aimed to analyze the incidence of SF and its correlation with clinical events after DES implantation and the outcome of re-intervention for symptomatic in-stent restenosis (ISR) induced by stent fracture (SF). SF is associated with a high rate of clinical events after the implantation of drug-eluting stents (DES). However, the chronological rate of SF and the effect of SF on clinical outcomes from a large patient population remain underreported. A total of 6,555 patients with 16482 DES in 10751 diseased vessels and surveillance angiography between November 2003 and January 2014 were prospectively studied. The primary endpoints included the incidence of SF, in-stent restenosis (ISR), target lesion revascularization (TLR), and definite stent thrombosis (ST) at the end of follow-up before and after propensity score matching. Clinical outcomes after TLR were also followed up. The SF rate was detected in 803 (12.3%) patients, 3,630 (22.0%) stents, and 1,852 (17.2%) diseased vessels. SF increased over time. SF was associated with higher unadjusted rates of ISR (42.1%), TLR (24.8%, n = 379), and definite ST (4.6%) compared with stents without fracture (10.7%, 6.6%, and 1.03%, all p < 0.001), and the differences remained significant after propensity score matching (all p < 0.05). There was no significant difference in any-cause or cardiac mortality between patients with and without SF. After 1,523 days of follow-up since the first surveillance angiography, repeat ISR was detected in 90 of 379 (23.8%) stents after reintervention, and 6 (7.5%) stents required repeat TLR. SF is more frequently observed after DES implantation. TLR was required in almost one-fourth of fractured stents. Increased events in the SF group did not translate into a difference in mortality compared with the non-SF group. Reintervention was associated with acceptable clinical results. Copyright © 2016 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Efficacy of therapy for hepatocellular carcinoma with portal vein tumor thrombus

PubMed Central

Chuan-Xing, Li; Xu, He; Bao-Shan, Hu; Yong, Li; Pei-Jian, Shao; Xian-Yi, Yu; Xiao-Ning, Luo

2011-01-01

The purpose of this study is to analyze the safety and clinical efficacy of transcatheter arterial chemoembolization (TACE) combined with portal vein stent and 125I implantation for the treatment of portal vein tumor thrombus (PVTT) in hepatocellular carcinoma. Fifty-six patients from our department diagnosed with advanced hepatocellular carcinoma with PVTT between January 2008 and December 30, 2010 were divided into two groups. Patients in Group A were treated with TACE and portal vein stent; patients in Group B were treated with TACE, portal vein stent and 125I implantation. The success rate of TACE with portal vein stent and 125I implantation was 100%, with no severe surgery-related complications. After an 8 mo follow-up, the total clinical benefit rates were 56.7 and 88.5% for Groups A and B, respectively (p < 0.05). The median survival times (mOS) for the two groups were 5.7 and 8.9 mo, respectively (p < 0.05). The median time of progression (mTTP) of the two groups were 5.3 and 7.9 mo, respectively (p < 0.05). The 2, 6, 8, 12 and 18 mo patency rates in Group A were 100, 93.3, 83.3, 53.3 and 36.6%. Those in Group B were 100, 100, 92.3, 84.6 and 80.7%. The 2, 6 and 8 mo patency rates showed no statistical differences (p > 0.05), but the 12 and 18 mo rates did (p < 0.05). Our results suggest that TACE combined with portal vein stent and 125I implantation are both safe and effective, and 125I implantation can further postpone the restenosis of the portal vein effectively. PMID:22037354

Impact of vessel curvature on neointimal healing after stent implantation as assessed by optical coherence tomography.

PubMed

Fu, Yandong; Zhang, Shaotao; Du, Hongwei; Li, Lulu; Wang, Chao; Zheng, Gonghui; Wang, Yan; Dong, Hui; Jia, Haibo; Yu, Bo

2018-04-01

Previous studies have indicated that stent implantation could alter the vessel geometry, which may impact the neointimal healing process. Curvature is an important parameter for evaluating vessel geometry. The purpose of our study was to investigate the relationship between vessel curvature and neointimal healing after stent implantation. Fifty-nine patients with acute coronary syndrome (ACS) who underwent stent implantation were enrolled in the study. According to the post-percutaneous coronary intervention vessel curvature measured by quantitative coronary angiography, patients were divided into high (n = 30) and low (n = 29) curvature groups. Neointimal thickness and area together with the neointimal type were assessed by optical coherence tomography at a 6-month follow-up. Baseline clinical characteristics were comparable between the 2 groups. The vessel curvature at pre- and 6-month follow-up was significantly higher in the high curvature group than the low curvature group. At 6-month follow-up, neointimal thickness (0.22 [0.08-0.32] mm vs. 0.10 [0.07-0.16] mm, P = .043) and neointimal area (1.86 [0.66-2.66] vs. 0.82 [0.60-1.41] mm, P = .030) were significantly higher in the high curvature group than the low curvature group. In the high curvature group, the incidence of the heterogeneous neointimal type was higher than that in the low curvature group (50.00% vs. 17.20%, respectively, P = .004), whereas the frequency of the homogeneous neointimal type was lower (43.30% vs. 82.80%, respectively, P = .004) in the high curvature group than the low curvature group. Higher vessel curvature after stent implantation may potentially have an impact on the neointimal healing with a higher incidence of heterogeneous neointimal.

Bioresorbable Electronic Stent Integrated with Therapeutic Nanoparticles for Endovascular Diseases.

PubMed

Son, Donghee; Lee, Jongha; Lee, Dong Jun; Ghaffari, Roozbeh; Yun, Sumin; Kim, Seok Joo; Lee, Ji Eun; Cho, Hye Rim; Yoon, Soonho; Yang, Shixuan; Lee, Seunghyun; Qiao, Shutao; Ling, Daishun; Shin, Sanghun; Song, Jun-Kyul; Kim, Jaemin; Kim, Taeho; Lee, Hakyong; Kim, Jonghoon; Soh, Min; Lee, Nohyun; Hwang, Cheol Seong; Nam, Sangwook; Lu, Nanshu; Hyeon, Taeghwan; Choi, Seung Hong; Kim, Dae-Hyeong

2015-06-23

Implantable endovascular devices such as bare metal, drug eluting, and bioresorbable stents have transformed interventional care by providing continuous structural and mechanical support to many peripheral, neural, and coronary arteries affected by blockage. Although effective in achieving immediate restoration of blood flow, the long-term re-endothelialization and inflammation induced by mechanical stents are difficult to diagnose or treat. Here we present nanomaterial designs and integration strategies for the bioresorbable electronic stent with drug-infused functionalized nanoparticles to enable flow sensing, temperature monitoring, data storage, wireless power/data transmission, inflammation suppression, localized drug delivery, and hyperthermia therapy. In vivo and ex vivo animal experiments as well as in vitro cell studies demonstrate the previously unrecognized potential for bioresorbable electronic implants coupled with bioinert therapeutic nanoparticles in the endovascular system.

Endovascular Stent Treatment for Symptomatic Benign Iliofemoral Venous Occlusive Disease: Long-Term Results 1987-2009

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gutzeit, A., E-mail: andreas.gutzeit@ksw.ch; Zollikofer, Ch. L., E-mail: Christoph.Zollikofer@ksb.ch; Dettling-Pizzolato, M., E-mail: Mira.Dettling@ksw.ch

Venous stenting has been shown to effectively treat iliofemoral venous obstruction with good short- and mid-term results. The aim of this study was to investigate long-term clinical outcome and stent patency. Twenty patients were treated with venous stenting for benign disease at our institution between 1987 and 2005. Fifteen of 20 patients (15 female, mean age at time of stent implantation 38 years [range 18-66]) returned for a clinical visit, a plain X-ray of the stent, and a Duplex ultrasound. Four patients were lost to follow-up, and one patient died 277 months after stent placement although a good clinical resultmore » was documented 267 months after stent placement. Mean follow-up after stent placement was 167.8 months (13.9 years) (range 71 (6 years) to 267 months [22 years]). No patient needed an additional venous intervention after stent implantation. No significant difference between the circumference of the thigh on the stented side (mean 55.1 cm [range 47.0-70.0]) compared with the contralateral thigh (mean 54.9 cm [range 47.0-70.0]) (p = 0.684) was seen. There was a nonsignificant trend toward higher flow velocities within the stent (mean 30.8 cm/s [range 10.0-48.0]) and the corresponding vein segment on the contralateral side (mean 25.2 cm/s [range 12.0-47.0]) (p = 0.065). Stent integrity was confirmed in 14 of 15 cases. Only one stent showed a fracture, as documented on x-ray, without any impairment of flow. Venous stenting using Wallstents showed excellent long-term clinical outcome and primary patency rate.« less

Biological effect of microengineered grooved stents on strut healing: a randomised OCT-based comparative study in humans

PubMed Central

Vesga, Boris; Hernandez, Hector; Higuera, Sergio; Gasior, Pawel; Echeveri, Dario; Delgado, Juan A; Dager, Antonio; Arana, Camilo; Simonton, Charles; Maehara, Akiko; Palmaz, Julio; Granada, Juan F

2017-01-01

Objective To evaluate the biological effect of microengineered stent grooves (MSG) on early strut healing in humans by performing optical coherence tomography (OCT) analysis 3 weeks following the implantation. Background In the experimental setting, MSG accelerate endothelial cell migration and reduce neointimal proliferation compared with bare metal stent (BMS). Methods A total of 37 patients undergoing percutaneous coronary intervention with de novo coronary lesions were randomly assigned to either MSG (n=19) or an identical BMS controls (n=18). All patients underwent OCT imaging at 3 weeks. A total of 7959 struts were included in the final analysis. Results At 3 weeks following stent implantation, almost all struts analysed (~97%) had evidence of tissue coverage. The percentage of partially covered struts was comparable between both groups. However, the percentage of fully embedded struts was higher in the BMS group (81.22%, 49.75–95.52) compared with the MSG group (74.21%, 58.85–86.38). The stent-level analysis demonstrated reduction in neointimal formation (neointimal hyperplasia area and volume reduction of ~14% and ~19%, respectively) in the MSG versus the BMS group. In the strut-level analysis, an even greater reduction (~22% in neointimal thickness) was seen in the MSG group. Layered neointimal was present in ~6% of the OCT frames in the BMS group while it was not present in the MSG group. Conclusions MSG induced a more homogeneous and predictable pattern of surface healing in the early stages following stent implantation. The biological effect of MSG on stent healing has the potential to improve the safety profile of current generation drug-eluting stents. Classifications BMS, OCT, clinical trials. PMID:28674616

Biological effect of microengineered grooved stents on strut healing: a randomised OCT-based comparative study in humans.

PubMed

Vesga, Boris; Hernandez, Hector; Higuera, Sergio; Gasior, Pawel; Echeveri, Dario; Delgado, Juan A; Dager, Antonio; Arana, Camilo; Simonton, Charles; Maehara, Akiko; Palmaz, Julio; Granada, Juan F

2017-01-01

To evaluate the biological effect of microengineered stent grooves (MSG) on early strut healing in humans by performing optical coherence tomography (OCT) analysis 3 weeks following the implantation. In the experimental setting, MSG accelerate endothelial cell migration and reduce neointimal proliferation compared with bare metal stent (BMS). A total of 37 patients undergoing percutaneous coronary intervention with de novo coronary lesions were randomly assigned to either MSG (n=19) or an identical BMS controls (n=18). All patients underwent OCT imaging at 3 weeks. A total of 7959 struts were included in the final analysis. At 3 weeks following stent implantation, almost all struts analysed (~97%) had evidence of tissue coverage. The percentage of partially covered struts was comparable between both groups. However, the percentage of fully embedded struts was higher in the BMS group (81.22%, 49.75-95.52) compared with the MSG group (74.21%, 58.85-86.38). The stent-level analysis demonstrated reduction in neointimal formation (neointimal hyperplasia area and volume reduction of ~14% and ~19%, respectively) in the MSG versus the BMS group. In the strut-level analysis, an even greater reduction (~22% in neointimal thickness) was seen in the MSG group. Layered neointimal was present in ~6% of the OCT frames in the BMS group while it was not present in the MSG group. MSG induced a more homogeneous and predictable pattern of surface healing in the early stages following stent implantation. The biological effect of MSG on stent healing has the potential to improve the safety profile of current generation drug-eluting stents. BMS, OCT, clinical trials.

Angiographic patterns of restenosis with 2nd generation drug-eluting stent: comparative analysis from a 10-year single-center experience .

PubMed

Lee, Sahmin; Yoon, Chang-Hwan; Oh, Il-Young; Suh, Jung-Won; Cho, Young-Seok; Cho, Goo-Yeong; Chae, In-Ho; Choi, Dong-Ju; Youn, Tae-Jin

2015-01-01

The angiographic features of restenosis contain prognostic information. However, restenosis patterns of the new generation drug-eluting stents (DES), everolimus-(EES) and resolute zotarolimus-eluting stent (ZES) have not been described.A total of 210 consecutive patients with DES restenosis were enrolled from 2003 to 2012. We analyzed 217 restenotic lesions after DES implantation, and compared the morphologic characteristics of the 2nd generation DES restenosis to those of restenosis with 2 first generation DES, sirolimus-(SES) and paclitaxel-eluting stent (PES).Baseline characteristics were comparable between the different stent groups. The incidence of focal restenosis was significantly lower for PES than the other stents (49.5% versus 87.0%, 76.2%, and 82.1% for PES versus SES, EES, and ZES, respectively, P < 0.001). When considering the pattern of restenosis solely within the stent margins, a further clear distinction between PES and other stents was observed (40.0% versus 92.9%, 88.9%, and 81.2% in PES versus SES, EES, and ZES, respectively, P < 0.001). There were no significant differences in restenosis patterns among SES, EES, and ZES. In multivariate analysis, PES implantation, hypertension, and age were associated with non-focal type of restenosis after DES implantation. After the introduction of EES and ZES into routine clinical practice in 2008, focal restenosis significantly increased from 63.9% to 76.7% and diffuse restenosis significantly decreased from 26.4% to 11.0% (P = 0.045).Focal restenosis was the most common pattern of restenosis in the new generation DES and the incidence of diffuse restenosis significantly decreased with the introduction of the 2nd generation DES.

Potential mechanisms of in-stent occlusion in the femoropopliteal artery: an angioscopic assessment.

PubMed

Ishihara, Takayuki; Iida, Osamu; Okamoto, Shin; Fujita, Masashi; Masuda, Masaharu; Nanto, Kiyonori; Shiraki, Tatsuya; Kanda, Takashi; Tsujimura, Takuya; Okuno, Shota; Yanaka, Koji; Uematsu, Masaaki

2017-10-01

Although stent implantation has become widespread for the treatment of patients with peripheral artery disease with femoropopliteal (FP) lesions, in-stent restenosis, especially in-stent occlusion (ISO), remains as a major concern for refractory recurrence. Furthermore, the mechanisms of ISO in FP lesions have not been well elucidated. We performed angioscopy for 6 lesions (bare-metal stent: 3, drug-eluting stent: 3) from 5 patients (mean age 74 ± 10 years, male 40 %) with ISO in the FP artery immediately after wire-passing or thrombus aspiration. The presence of thrombus as well as the presence and location of organic stenosis were evaluated. Median duration from stent implantation to angioscopic evaluation was 1099.5 (514.5-2272.5) days, while the duration from recurrence of symptoms to angioscopic evaluation was 45 (5.75-60) days. Mixed thrombi were observed in all stents. Organic stenosis was detected at the proximal edge of the stents in 5 lesions. Organic stenosis was observed at the overlapping segment of the stent in one lesion. The distal edge of the stents could be evaluated in 3 lesions, and all of them showed organic stenosis at the site. Mixed thrombi and organic stenosis were observed in all stents. Partial development of organic stenosis in a stent followed by thrombus formation may be the potential mechanism of the development of ISO in the FP artery though the sample size of this study was small and it had no serial angioscopic data so that we should consider it as preliminary one at best.

Immediate and late clinical and angiographic outcomes after GFX coronary stenting: is high-pressure balloon dilatation necessary?

PubMed

Park, S W; Hong, M K; Lee, C W; Kim, J J; Park, H K; Cho, G Y; Kang, D H; Song, J K; Park, S J

2000-08-01

The GFX stent is a balloon-expandable stent made of sinusoidal element of stainless steel. The adjunct high-pressure balloon dilatations were usually recommended in routine stenting procedure. The aim of this study was to evaluate the immediate and long-term clinical and angiographic outcomes and to investigate the necessity of high-pressure balloon dilatation during GFX stenting. In all, 172 consecutive patients underwent single 12 or 18 mm GFX stent implantation in 188 native coronary lesions. Two types of stenting technique were used: (1) stent size of a final stent-to-artery ratio of 1:1 (inflation pressure > 10 atm, high-pressure group), and (2) stent size of 0.5 mm bigger than reference vessel (inflation pressure < or = 10 atm, low-pressure group). The adjunct high-pressure balloon dilatations were performed only in cases of suboptimal results. The adjunct high-pressure balloon dilatation was required in 11 of 83 lesions (13%) in the high-pressure group and in 7 of 105 lesions (7%) in the low-pressure group (p = 0.203). Procedural success rate was 100%. There were no significant differences of in-hospital and long-term clinical events between the two groups. The overall angiographic restenosis rate was 17.7%; 18.4% in the high-pressure group and 17.1% in the low-pressure group (p = 0.991). The GFX stent is a safe and effective device with a high procedural success rate and favorable late clinical outcome for treatment of native coronary artery disease. Further randomized trials may be needed to compare stenting techniques in GFX stent implantation.

Bioabsorbable Stent Quo Vadis: A Case for Nano-Theranostics

PubMed Central

Gundogan, Buket; Tan, Aaron; Farhatnia, Yasmin; Alavijeh, Mohammad S.; Cui, Zhanfeng; Seifalian, Alexander M.

2014-01-01

Percutaneous coronary intervention (PCI) is one of the most commonly performed invasive medical procedures in medicine today. Since the first coronary balloon angioplasty in 1977, interventional cardiology has seen a wide array of developments in PCI. Bare metal stents (BMS) were soon superseded by the revolutionary drug-eluting stents (DES), which aimed to address the issue of restenosis found with BMS. However, evidence began to mount against DES, with late-stent thrombosis (ST) rates being higher than that of BMS. The bioabsorbable stent may be a promising alternative, providing vessel patency and support for the necessary time required and thereafter degrade into safe non-toxic compounds which are reabsorbed by the body. This temporary presence provides no triggers for ST, which is brought about by non-endothelialized stent struts and drug polymers remaining in vivo for extended periods of time. Likewise, nano-theranostics incorporated into a bioabsorbable stent of the future may provide an incredibly valuable single platform offering both therapeutic and diagnostic capabilities. Such a stent may allow delivery of therapeutic particles to specific sites thus keeping potential toxicity to a minimum, improved ease of tracking delivery in vivo by embedding imaging agents, controlled rate of therapy release and protection of the implanted therapy. Indeed, nanocarriers may allow an increased therapeutic index as well as offer novel post-stent implantation imaging and diagnostic methods for atherosclerosis, restenosis and thrombosis. It is envisioned that a nano-theranostic stent may well form the cornerstone of future stent designs in clinical practice. PMID:24672583

Evaluation of a Bioabsorbable Self-Expandable Vein Stent-Base Made of Poly(L-lactide) In Vitro and In Vivo.

PubMed

Løvdal, Alexandra Liv Vest; Calve, Sarah; Yang, Shuo; Van Alstine, William; Binkert, Christoph A; Klausen, Kasper

2017-01-01

This study was designed to evaluate performance and tissue response to a self-expandable bioabsorbable vein stent-base cut from a tube with enhanced stiffness and strength in vitro and in vivo. A diamond-shaped stent-base was cut from a sequential biaxially strained poly(L-lactide) (PLLA) tube for optimized performance. The performance of the stent-base was evaluated in a finite element analysis model, and validation was attempted in vitro through a cyclic flat-plate compression and radial force measurement. The performance of the stent-base was tested in vivo using 3 sheep with 2 implants each for 2 and 3½ weeks, respectively. In vitro the stent-base showed an elliptical deformation but no fractures. In vivo the stent-base showed adequate radial force and no migration. All implanted stent-bases showed multiple fractures not only at the predicted stress zones but at all connecting points. Fragments of the caudal stent-base stayed in the vein wall indicating sufficient tissue coverage to avoid embolization of the fractured stent pieces, whereas fragments from the cranial device remaining were few. Neointima formation was confirmed histologically at 2 and 3½ weeks. A bioabsorbable self-expandable stent-base made from PLLA for large veins seems feasible, but over time, the PLLA used in this study appears too stiff and lacks the sufficient flexibility to move with the vena cava, causing multiple fractures.

Evaluation of a Bioabsorbable Self-Expandable Vein Stent-Base Made of Poly(l-lactide) In Vitro and In Vivo

DOE Office of Scientific and Technical Information (OSTI.GOV)

Løvdal, Alexandra Liv Vest, E-mail: alvlo@nanotech.dtu.dk; Calve, Sarah; Yang, Shuo

PurposeThis study was designed to evaluate performance and tissue response to a self-expandable bioabsorbable vein stent-base cut from a tube with enhanced stiffness and strength in vitro and in vivo.MethodsA diamond-shaped stent-base was cut from a sequential biaxially strained poly(l-lactide) (PLLA) tube for optimized performance. The performance of the stent-base was evaluated in a finite element analysis model, and validation was attempted in vitro through a cyclic flat-plate compression and radial force measurement. The performance of the stent-base was tested in vivo using 3 sheep with 2 implants each for 2 and 3½ weeks, respectively.ResultsIn vitro the stent-base showed anmore » elliptical deformation but no fractures. In vivo the stent-base showed adequate radial force and no migration. All implanted stent-bases showed multiple fractures not only at the predicted stress zones but at all connecting points. Fragments of the caudal stent-base stayed in the vein wall indicating sufficient tissue coverage to avoid embolization of the fractured stent pieces, whereas fragments from the cranial device remaining were few. Neointima formation was confirmed histologically at 2 and 3½ weeks.ConclusionA bioabsorbable self-expandable stent-base made from PLLA for large veins seems feasible, but over time, the PLLA used in this study appears too stiff and lacks the sufficient flexibility to move with the vena cava, causing multiple fractures.« less

Endovascular Treatment of Severely Calcified Femoropopliteal Lesions Using the "Pave-and-Crack" Technique: Technical Description and 12-Month Results.

PubMed

Dias-Neto, Marina; Matschuck, Manuela; Bausback, Yvonne; Banning-Eichenseher, Ursula; Steiner, Sabine; Branzan, Daniela; Staab, Holger; Varcoe, Ramon L; Scheinert, Dierk; Schmidt, Andrej

2018-06-01

To report midterm results of the "pave-and-crack" technique to facilitate safe and effective scaffolding of heavily calcified femoropopliteal lesions in preparation for delivery of a Supera interwoven stent. Data were collected retrospectively on 67 consecutive patients (mean age 71±8 years; 54 men) treated with this technique between November 2011 and February 2017 at a single center. A third (22/64, 34%) of the patients had critical limb ischemia (CLI). Most lesions were TASC D (52/67, 78%), and the majority were occlusions (61/66, 92%). The mean lesion length was 26.9±11.2 cm. Nearly two-thirds (40/64, 62%) had grade 4 calcification (Peripheral Arterial Calcium Scoring System). To prepare for Supera stenting, the most heavily calcified segments of the lesion were predilated aggressively to obliterate recoil. A Viabahn stent-graft was then implanted to "pave" the lesion and protect from vessel rupture as aggressive predilation continued until the calcified plaque was "cracked" before lining the entire lesion with a Supera stent. Patency and target lesion revascularization (TLR) rates were estimated using the Kaplan-Meier method. Procedural success was achieved in 100% and technical success (residual stenosis <30%) in 98% (66/67). The mean cumulative stent lengths were 16±9 cm for the Viabahn and 23±12 cm for the Supera. Only 2 complications occurred (distal embolization and access-site pseudoaneurysm). Two CLI patients died within 30 days, and 3 patients (all claudicants) underwent a TLR. Patients were followed for a mean 19±18 months, during which another 2 CLI patients died and 1 patient had a major amputation. One-year primary and secondary patency estimates were 79% and 91%, respectively; freedom from TLR was 85%. Despite severe lesion calcification, patients experienced high technical success and a safe and durable therapy at midterm follow-up with the femoropopliteal "pave-and-crack" technique.

In-Graft Endovascular Stenting Repair for Supravalvular Stenosis From Aortic Rupture After Balloon-Expanding Transcatheter Aortic Valve Implantation.

PubMed

Furukawa, Nobuyuki; Scholtz, Werner; Haas, Nikolaus; Ensminger, Stephan; Gummert, Jan; Börgermann, Jochen

2015-01-01

An 81-year-old man with high-grade aortic valve stenosis and status post-coronary artery bypass grafting and supracoronary replacement of the ascending aorta was referred for transcatheter aortic valve implantation. He was in New York Heart Association class III and had dyspnea. After appropriate screening, we implanted a 29-mm SAPIEN XT valve (Edwards Lifesciences, Irvine, CA USA) through a transapical approach because of severe peripheral arterial occlusive disease. Postinterventional aortography revealed correct positioning and function of the valve and free coronary ostia but contrast extravasation in the vicinity of the interposed vascular prosthesis, resulting in severe luminal narrowing. We chose to manage the stenosis with an endovascular stent. After stenting, extravascular compression was markedly reduced, and the pressure gradient disappeared. The patient was discharged home on the 20th postoperative day. Three months later, computed tomography depicted correct positioning of both grafts. The patient's general health is good, and he is now in New York Heart Association class II. This case illustrates a complication of transcatheter aortic valve implantation specific for patients with an ascending aortic graft. Although stenting may be a good solution, as depicted by this case, self-expanding transcatheter aortic valves should be preferred in patients with ascending aortic grafts to avoid the described complication.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vajda, Zsolt, E-mail: Z.Vajda@klinikum-stuttgart.de; Guethe, Thomas, E-mail: T.Guethe@klinikum-stuttgart.de; Perez, Marta Aguilar, E-mail: M.Aguilar@klinikum-stuttgart.de

Stenting in intracranial atherosclerotic disease (ICAD) is increasingly debated, due to issues of procedural safety, technical efficacy, and in-stent recurrent stenoses (ISR). In the present study, feasibility, safety, and efficacy of angioplasty using a drug-eluting balloon (DEB) followed by the implantation of a self-expanding stent (Enterprise) were evaluated for the treatment of ICAD lesions. Fifty-two patients (median age: 71 years; range: 54-86 years; male/female ratio 37:15) underwent stenting of high-grade ICAD lesions between February 2010 and November 2011 in a single center. Angioplasty using a paclitaxel coated SeQuent Please (B. Braun, Germany) or DIOR (Eurocor, Germany) coronary PTCA balloon, followedmore » by the implantation of a self-expanding stent (Enterprise, Codman, USA) was performed in 54 lesions. Angiographic and clinical follow-up was performed at 6 and 12 weeks, 6 and 12 months, and yearly thereafter. Technical success rate, periprocedural complications, occurrence of recurrent ischemic symptoms, and the development of an ISR were analyzed. Angioplasty using a DEB followed by stent implantation was successfully performed in 44 (81 %) cases. DEB insertion failed in 19 % of the cases and angioplasty was finally performed using a conventional PTCA balloon. The combined procedure related permanent neurologic morbidity and mortality rate (stroke, ICH, and subarachnoid hemorrhage) at 30 days and beyond was 5 %. Angiographic and clinical follow-up were obtained in 33 (61 %) lesions in 32 patients. Recurrent stenosis was seen in one (3 %) lesion. Angioplasty and stenting using a DEB is safe and yields encouragingly low ISR rates. Further technical developments to improve lesion accessibility are, nevertheless, mandatory.« less

Delayed Esophageal Hemorrhage Caused by a Metal Stent: Treatment with Embolization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kos, Xavier; Trotteur, Genevieve; Dondelinger, Robert F.

We report a case of life-threatening esophageal hemorrhage after metal stent implantation successfully treated by arterial embolization. An 85-year-old woman was admitted in shock secondary to massive hematemesis and melena. Recent medical history revealed esophageal cancer treated 8 weeks previously by endoesophageal radiotherapy (40 Gy) and endoscopic placement of a covered Wallstent prosthesis. Selective arteriography of the fifth posterior right intercostal artery showed massive contrast extravasation in the esophagus. Embolization was performed with 150-250-{mu}m polyvinyl alcohol particles. Follow-up at 5 months was uneventful. Arteriography and embolization are advised when severe hemorrhage occurs after esophageal implantation of metal stents.

The impact of precise robotic lesion length measurement on stent length selection: ramifications for stent savings.

PubMed

Campbell, Paul T; Kruse, Kevin R; Kroll, Christopher R; Patterson, Janet Y; Esposito, Michele J

2015-09-01

Coronary stent deployment outcomes can be negatively impacted by inaccurate lesion measurement and inappropriate stent length selection (SLS). We compared visual estimate of these parameters to those provided by the CorPath 200® Robotic PCI System. Sixty consecutive patients who underwent coronary stent placement utilizing the CorPath System were evaluated. The treating physician assessed orthogonal images and provided visual estimates of lesion length and SLS. The robotic system was then used for the same measures. SLS was considered to be accurate when visual estimate and robotic measures were in agreement. Visual estimate SLSs were considered to be "short" or "long" if they were below or above the robotic-selected stents, respectively. Only 35% (21/60) of visually estimated lesions resulted in accurate SLS, whereas 33% (20/60) and 32% (19/60) of the visually estimated SLSs were long and short, respectively. In 5 cases (8.3%), 1 less stent was placed based on the robotic lesion measurement being shorter than the visual estimate. Visual estimate assessment of lesion length and SLS is highly variable with 65% of the cases being inaccurately measured when compared to objective measures obtained from the robotic system. The 32% of the cases where lesions were visually estimated to be short represents cases that often require the use of extra stents after the full lesion is not covered by 1 stent [longitudinal geographic miss (LGM)]. Further, these data showed that the use of the robotic system prevented the use of extra stents in 8.3% of the cases. Measurement of lesions with robotic PCI may reduce measurement errors, need for extra stents, and LGM. Copyright © 2015 Elsevier Inc. All rights reserved.

Percutaneous Transcatheter One-Step Mechanical Aortic Disc Valve Prosthesis Implantation: A Preliminary Feasibility Study in Swine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sochman, Jan; Peregrin, Jan H.; Rocek, Miloslav

Purpose. To evaluate the feasibility of one-step implantation of a new type of stent-based mechanical aortic disc valve prosthesis (MADVP) above and across the native aortic valve and its short-term function in swine with both functional and dysfunctional native valves. Methods. The MADVP consisted of a folding disc valve made of silicone elastomer attached to either a nitinol Z-stent (Z model) or a nitinol cross-braided stent (SX model). Implantation of 10 MADVPs (6 Z and 4 SX models) was attempted in 10 swine: 4 (2 Z and 2 SX models) with a functional native valve and 6 (4 Z andmore » 2 SX models) with aortic regurgitation induced either by intentional valve injury or by MADVP placement across the native valve. MADVP function was observed for up to 3 hr after implantation. Results. MADVP implantation was successful in 9 swine. One animal died of induced massive regurgitation prior to implantation. Four MADVPs implanted above functioning native valves exhibited good function. In 5 swine with regurgitation, MADVP implantation corrected the induced native valve dysfunction and the device's continuous good function was observed in 4 animals. One MADVP (SX model) placed across native valve gradually migrated into the left ventricle. Conclusion. The tested MADVP can be implanted above and across the native valve in a one-step procedure and can replace the function of the regurgitating native valve. Further technical development and testing are warranted, preferably with a manufactured MADVP.« less

Acute ST-Elevation Myocardial Infarction after Coronary Stent Fracture.

PubMed

Rafighdust, Abbasali; Eshraghi, Ali

2015-10-27

The invention of the drug-eluting stent (DES) has brought about revolutionary changes in the field of interventional cardiology. In the DES era, in-stent restenosis has declined but new issues such as stent thrombosis have emerged. One of the emerging paradigms in the DES era is stent fracture. There are reports about stent fracture leading to in-stent restenosis or stent thrombosis. Most of these reports concern the Sirolimus-eluting stent. The present case is a representation of a Biolimus-eluting stent fracture. We introduce a 64-year-old male patient, for whom the BioMatrix stent was deployed in the right coronary artery. Five months after the implantation, he experienced acute myocardial infarction, with stent fracture leading to stent thrombosis being the causative mechanism. Another DES (Cypher) was used to manage this situation, and the final result was good.

Stent implantation influence wall shear stress evolution

NASA Astrophysics Data System (ADS)

Bernad, S. I.; Totorean, A. F.; Bosioc, A. I.; Petre, I.; Bernad, E. S.

2016-06-01

Local hemodynamic factors are known affect the natural history of the restenosis critically after coronary stenting of atherosclerosis. Stent-induced flows disturbance magnitude dependent directly on the strut design. The impact of flow alterations around struts vary as the strut geometrical parameters change. Our results provide data regarding the hemodynamic parameters for the blood flow in both stenosed and stented coronary artery under physiological conditions, namely wall shear stress and pressure drop.

Computational hemodynamics of an implanted coronary stent based on three-dimensional cine angiography reconstruction.

PubMed

Chen, Mounter C Y; Lu, Po-Chien; Chen, James S Y; Hwang, Ned H C

2005-01-01

Coronary stents are supportive wire meshes that keep narrow coronary arteries patent, reducing the risk of restenosis. Despite the common use of coronary stents, approximately 20-35% of them fail due to restenosis. Flow phenomena adjacent to the stent may contribute to restenosis. Three-dimensional computational fluid dynamics (CFD) and reconstruction based on biplane cine angiography were used to assess coronary geometry and volumetric blood flows. A patient-specific left anterior descending (LAD) artery was reconstructed from single-plane x-ray imaging. With corresponding electrocardiographic signals, images from the same time phase were selected from the angiograms for dynamic three-dimensional reconstruction. The resultant three-dimensional LAD artery at end-diastole was adopted for detailed analysis. Both the geometries and flow fields, based on a computational model from CAE software (ANSYS and CATIA) and full three-dimensional Navier-Stroke equations in the CFD-ACE+ software, respectively, changed dramatically after stent placement. Flow fields showed a complex three-dimensional spiral motion due to arterial tortuosity. The corresponding wall shear stresses, pressure gradient, and flow field all varied significantly after stent placement. Combined angiography and CFD techniques allow more detailed investigation of flow patterns in various segments. The implanted stent(s) may be quantitatively studied from the proposed hemodynamic modeling approach.

Biological effect on restenosis and vascular healing of encapsulated paclitaxel nanocrystals delivered via coated balloon technology in the familial hypercholesterolaemic swine model of in-stent restenosis.

PubMed

Cheng, Yanping; Shibuya, Masahiko; McGregor, Jenn; Conditt, Gerard B; Yi, Geng-Hua; Kaluza, Greg L; Gray, William; Doshi, Manish; Sojitra, Prakash; Granada, Juan F

2016-10-20

The aim of this study was to evaluate the biological efficacy of a novel lower-dose (2.5 µg/mm2) encapsulated paclitaxel nanocrystal-coated balloon (Nano-PCB) in the familial hypercholesterolaemic swine (FHS) model of iliofemoral in-stent restenosis. Nano-PCB pharmacokinetics were assessed in 20 femoral arteries (domestic swine). Biological efficacy was evaluated in ten FHS: 14 days following bare metal stent implantation each stent segment was randomised to a clinically available PCB (IN.PACT, n=14), the Nano-PCB (n=14) or an uncoated balloon (n=12). Angiographic, optical coherence tomography and histological evaluation was performed at 28 days after treatment. Arterial paclitaxel concentration was 120.7 ng/mg at one hour and 7.65 ng/mg of tissue at 28 days with the Nano-PCB. Compared to the control uncoated group, both PCBs significantly reduced percent area stenosis (Nano-PCB: 36.0±14.2%, IN.PACT: 29.3±9.2% vs control: 67.9±15.1%, p<0.001). Neointimal distribution in the entire stent length was more homogenous in the Nano-PCB. Histological evaluation showed comparable degrees of neointimal proliferation in both PCBs; however, the Nano-PCB showed slightly higher levels of neointimal maturity and endothelialisation. Lower-dose encapsulated paclitaxel nanocrystals delivered via a coated balloon displayed comparable biological efficacy with superior healing features compared to a clinically validated PCB technology.

Portal venous stent placement for treatment of portal hypertension caused by benign main portal vein stenosis.

PubMed

Shan, Hong; Xiao, Xiang-Sheng; Huang, Ming-Sheng; Ouyang, Qiang; Jiang, Zai-Bo

2005-06-07

To evaluate the value of endovascular stent in the treatment of portal hypertension caused by benign main portal vein stenosis. Portal vein stents were implanted in six patients with benign main portal vein stenosis (inflammatory stenosis in three cases, postprocedure of liver transplantation in another three cases). Changes in portal vein pressure, portal vein patency, relative clinical symptoms, complications, and survival were evaluated. Six metallic stents were successfully placed across the portal vein stenotic or obstructive lesions in six patients. Mean portal venous pressure decreased significantly after stent implantation from (37.3+/-4.7) cm H(2)O to (18.0+/-1.9) cm H(2)O. The portal blood flow restored and the symptoms caused by portal hypertension were eliminated. There were no severe procedure-related complications. The patients were followed up for 1-48 mo. The portal vein remained patent during follow-up. All patients survived except for one patient who died of other complications of liver transplantation. Percutaneous portal vein stent placement for the treatment of portal hypertension caused by benign main portal vein stenosis is safe and effective.

Prospective unmasked randomized evaluation of the iStent inject® versus two ocular hypotensive agents in patients with primary open-angle glaucoma

PubMed Central

Fea, Antonio M; Belda, Jose I; Rękas, Marek; Jünemann, Anselm; Chang, Lydia; Pablo, Luis; Voskanyan, Lilit; Katz, L Jay

2014-01-01

Purpose The purpose of this study was to compare outcomes of subjects with open-angle glaucoma (OAG) not controlled on one medication who underwent either implantation of two iStent inject® trabecular micro-bypass devices or received medical therapy consisting of a fixed combination of latanoprost/timolol. Patients and methods Of 192 subjects who qualified for the study and were enrolled, 94 were randomized to surgery with implantation of two iStent inject® devices in the treated eye and 98 to receive medical therapy. Results At the month 12 visit, 94.7% of eyes (89/94) in the stent group reported an unmedicated intraocular pressure (IOP) reduction of ≥20% versus baseline unmedicated IOP, and 91.8% of eyes (88/98) in the medical therapy group reported an IOP reduction ≥20% versus baseline unmedicated IOP. A 17.5% between-group treatment difference in favor of the iStent inject group was statistically significant (P=0.02) at the ≥50% level of IOP reduction. An IOP ≤18 mmHg was reported in 92.6% of eyes (87/94) in the iStent inject group and 89.8% of eyes (88/98) in the medical therapy group. Mean (standard deviation) IOP decreases from screening of 8.1 (2.6) mmHg and 7.3 (2.2) mmHg were reported in the iStent inject and medical therapy groups, respectively. A high safety profile was also noted in this study in both the iStent inject and medical therapy groups, as measured by stable best corrected visual acuity, cup-to-disc ratio, and adverse events. Conclusion These data show that the use of iStent inject is at least as effective as two medications, with the clinical benefit of reducing medication burden and assuring continuous treatment with full compliance to implant therapy as well as having a highly favorable safety profile. PMID:24855336

Bioresorbable scaffolds for percutaneous coronary interventions

PubMed Central

Gogas, Bill D.

2014-01-01

Innovations in drug-eluting stents (DES) have substantially reduced rates of in-segment restenosis and early stent thrombosis, improving clinical outcomes following percutaneous coronary interventions (PCI). However a fixed metallic implant in a vessel wall with restored patency and residual disease remains a precipitating factor for sustained local inflammation, in-stent neo-atherosclerosis and impaired vasomotor function increasing the risk for late complications attributed to late or very late stent thrombosis and late target lesion revascularization (TLR) (late catch-up). The quest for optimal coronary stenting continues by further innovations in stent design and by using biocompatible materials other than cobalt chromium, platinum chromium or stainless steel for engineering coronary implants. Bioresorbable scaffolds made of biodegradable polymers or biocorrodible metals with properties of transient vessel scaffolding, local drug-elution and future restoration of vessel anatomy, physiology and local hemodynamics have been recently developed. These devices have been utilized in selected clinical applications so far providing preliminary evidence of safety showing comparable performance with current generation drug-eluting stents (DES). Herein we provide a comprehensive overview of the current status of these technologies, we elaborate on the potential benefits of transient coronary scaffolds over permanent stents in the context of vascular reparation therapy, and we further focus on the evolving challenges these devices have to overcome to compete with current generation DES. Condensed Abstract:: The quest for optimizing percutaneous coronary interventions continues by iterative innovations in device materials beyond cobalt chromium, platinum chromium or stainless steel for engineering coronary implants. Bioresorbable scaffolds made of biodegradable polymers or biocorrodible metals with properties of transient vessel scaffolding; local drug-elution and future restoration of vessel anatomy, physiology and local hemodynamics were recently developed. These devices have been utilized in selected clinical applications providing preliminary evidence of safety showing comparable intermediate term clinical outcomes with current generation drug-eluting stents. PMID:25780795

A review of stent’s failure on patent ductus arteriosus

NASA Astrophysics Data System (ADS)

Lazim, Zulfaqih; Ismail, Al Emran; Taib, Ishkrizat; Atan, Bainun Akmal Mohd

2017-01-01

This paper presents a review of stent’s failure on patent ductus arteriosus (PDA). Ductus arteriosus (DA) is an opening for newborn babies and some patient that experienced cynotic congenital heart disease (CCHD) should maintain the duct opening for survival. To date, there are no specific research on mechanical stent failure study at DA. The challenging of the stent implantation on PDA is the PDA morphology. The failure of stent in term of stent fracture have been reported and reviewed in this paper. Furthermore, the failure prediction of stent is important for further stent design development. The morphology of PDA, stent type and material used in PDA and method for accessing the failure of stent is reviewed.

Evaluating the interaction of a tracheobronchial stent in an ovine in-vivo model.

PubMed

McGrath, Donnacha J; Thiebes, Anja Lena; Cornelissen, Christian G; O'Brien, Barry; Jockenhoevel, Stefan; Bruzzi, Mark; McHugh, Peter E

2018-04-01

Tracheobronchial stents are used to restore patency to stenosed airways. However, these devices are associated with many complications such as stent migration, granulation tissue formation, mucous plugging and stent strut fracture. Of these, granulation tissue formation is the complication that most frequently requires costly secondary interventions. In this study a biomechanical lung modelling framework recently developed by the authors to capture the lung in-vivo stress state under physiological loading is employed in conjunction with ovine pre-clinical stenting results and device experimental data to evaluate the effect of stent interaction on granulation tissue formation. Stenting is simulated using a validated model of a prototype covered laser-cut tracheobronchial stent in a semi-specific biomechanical lung model, and physiological loading is performed. Two computational methods are then used to predict possible granulation tissue formation: the standard method which utilises the increase in maximum principal stress change, and a newly proposed method which compares the change in contact pressure over a respiratory cycle. These computational predictions of granulation tissue formation are then compared to pre-clinical stenting observations after a 6-week implantation period. Experimental results of the pre-clinical stent implantation showed signs of granulation tissue formation both proximally and distally, with a greater proximal reaction. The standard method failed to show a correlation with the experimental results. However, the contact change method showed an apparent correlation with granulation tissue formation. These results suggest that this new method could be used as a tool to improve future device designs.

Anticoagulant and Antiplatelet Therapy in Patients with Atrial Fibrillation and Coronary Artery Disease

PubMed Central

Mischke, Karl; Knackstedt, Christian; Marx, Nikolaus

2012-01-01

Anticoagulation represents the mainstay of therapy for most patients with atrial fibrillation. Patients on oral anticoagulation often require concomitant antiplatelet therapy, mostly because of coronary artery disease. After coronary stent implantation, dual antiplatelet therapy is necessary. However, the combination of oral anticoagulation and antiplatelet therapy increases the bleeding risk. Risk scores such as the CHA2DS2-Vasc score and the HAS-BLED score help to identify both bleeding and stroke risk in individual patients. The guidelines of the European Society of Cardiology provide a rather detailed recommendation for patients on oral anticoagulation after coronary stent implantation. However, robust evidence is lacking for some of the recommendations, and especially for new oral anticoagulants and new antiplatelets few or no data are available. This review addresses some of the critical points of the guidelines and discusses potential advantages of new anticoagulants in patients with atrial fibrillation after stent implantation. PMID:22577538

Endovascular stent-based revascularization of malignant superior vena cava syndrome with concomitant implantation of a port device using a dual venous approach.

PubMed

Anton, Susanne; Oechtering, T; Stahlberg, E; Jacob, F; Kleemann, M; Barkhausen, J; Goltz, J P

2018-06-01

The aim of this paper is to evaluate the safety and efficacy of endovascular revascularization of malignant superior vena cava syndrome (SVCS) and simultaneous implantation of a totally implantable venous access port (TIVAP) using a dual venous approach. Retrospectively, 31 patients (mean age 67 ± 8 years) with malignant CVO who had undergone revascularization by implantation of a self-expanding stent into the superior vena cava (SVC) (Sinus XL®, OptiMed, Germany; n = 11 [Group1] and Protégé ™ EverFlex, Covidien, Ireland; n = 20 [Group 2]) via a transfemoral access were identified. Simultaneously, percutaneous access via a subclavian vein was used to (a) probe the lesion from above, (b) facilitate a through-and-through maneuver, and (c) implant a TIVAP. Primary endpoints with regard to the SVC syndrome were technical (residual stenosis < 30%) and clinical (relief of symptoms) success; with regard to TIVAP implantation technical success was defined as positioning of the functional catheter within the SVC. Secondary endpoints were complications as well as stent and TIVAP patency. Technical and clinical success rate were 100% for revascularization of the SVS and 100% for implantation of the TIVAP. One access site hematoma (minor complication, day 2) and one port-catheter-associated sepsis (major complication, day 18) were identified. Mean catheter days were 313 ± 370 days. Mean imaging follow-up was 184 ± 172 days. Estimated patency rates at 3, 6, and 12 months were 100% in Group 1 and 84, 84, and 56% in Group 2 (p = 0.338). Stent-based revascularization of malignant SVCS with concomitant implantation of a port device using a dual venous approach appears to be safe and effective.

Combined Open and Endovascular Repair for Aortic Arch Pathology

PubMed Central

Kang, Woong Chol; Ahn, Tae Hoon; Lee, Kyung Hoon; Moon, Chan Il; Han, Seung Hwan; Park, Chul-Hyun; Park, Kook-Yang; Kang, Jin Mo; Kim, Jung Ho

2010-01-01

Background and Objectives We describe our experience with combined open and endovascular repair in patients who have aortic arch pathology. Subjects and Methods This study is a retrospective analysis of 7 patients who underwent combined open and endovascular repair for aortic arch pathology. Medical records and radiographic information were reviewed. Results A total of 7 consecutive patients (5 men, 71.4%) underwent thoracic stent graft implantation. The mean age was 59.9±16.7 years. The indication for endovascular repair was aneurysmal degeneration in 5 patients, and rupture or impending rupture in 2 patients. In all 7 cases, supra-aortic transposition of the great vessels was performed successfully. Stent graft implantation was achieved in all cases. Surgical exposure of the access vessel was necessary in 2 patients. A total of 9 stent grafts were implanted (3 stent grafts in one patient). The Seal thoracic and the Valiant endovascular stent graft were implanted in 6 patients and 1 patient, respectively. There were no post-procedure deaths or neurologic complications. In 2 patients, bleeding and injury of access vessel were noted after the procedure. Postoperative endoleak was noted in 1 patient. One patient died at 10 months after the procedure due to a newly developed ascending aortic dissection. No patients required secondary intervention during the follow-up period. The aortic diameter decreased in 4 patients. In 3 patients, including 1 patient with endoleak, there was no change in aortic diameter. Conclusion Our experience suggests that combined open and endovascular repair for aortic arch pathology is safe and effective, with few complications. PMID:20830254

Long-term titrated IOP control with one, two, or three trabecular micro-bypass stents in open-angle glaucoma subjects on topical hypotensive medication: 42-month outcomes

PubMed Central

Erb, Carl; Carceller Guillamet, Amadeu; Fea, Antonio M; Voskanyan, Lilit; Giamporcaro, Jane Ellen; Hornbeak, Dana M

2018-01-01

Purpose Evaluate long-term outcomes after one, two, or three trabecular micro-bypass stents implanted in a standalone procedure in eyes with open-angle glaucoma taking ocular hypotensive medication. Patients and methods Prospective randomized ongoing study of 119 subjects (109 with 42-month follow-up) with open-angle glaucoma, preoperative intraocular pressure (IOP) 18–30 mmHg on one to three glaucoma medications, and unmedicated (post-washout) IOP 22–38 mmHg. Subjects were randomized to receive one (n=38), two (n=41), or three (n=40) iStent trabecular micro-bypass stents in a standalone procedure. Postoperatively, IOP was measured with medication and annually following washout. Data included IOP, medications, gonioscopy, pachymetry, visual field, visual acuity, adverse events, and slit-lamp and fundus examinations. Results Preoperative mean medicated IOP was 19.8±1.3 mmHg on 1.71 medications in one-stent eyes, 20.1±1.6 mmHg on 1.76 medications in two-stent eyes, and 20.4±1.8 mmHg on 1.53 medications in three-stent eyes. Post-washout IOP prior to stent implantation was 25.0±1.2, 25.0±1.7, and 25.1±1.9 mmHg in the three groups, respectively. Postoperatively, Month 42 medicated IOP was 15.0±2.8, 15.7±1.0 and 14.8±1.3 mmHg in the three groups, and post-washout IOP (Months 36–37) was 17.4±0.9, 15.8±1.1 and 14.2±1.5 mmHg, respectively. IOP reduction ≥20% without medication was achieved in 89%, 90%, and 92% of one-, two-, and three-stent eyes, respectively, at Month 12; and in 61%, 91%, and 91% of eyes, respectively, at Month 42. The need for additional medication remained consistent at Months 12 and 42 in multi-stent eyes (four two-stent eyes and three three-stent eyes at both time points), whereas it increased in single-stent eyes (four eyes at Month 12 versus 18 eyes at Month 42). Safety parameters were favorable in all groups. Conclusion The standalone implantation of either single or multiple iStent® device(s) produced safe, clinically meaningful IOP and medication reductions through 42 months postoperatively, with incrementally greater and more sustained reductions in multi-stent eyes. PMID:29440867

Efficacy and Safety of Dual Antiplatelet Therapy After Complex PCI.

PubMed

Giustino, Gennaro; Chieffo, Alaide; Palmerini, Tullio; Valgimigli, Marco; Feres, Fausto; Abizaid, Alexandre; Costa, Ricardo A; Hong, Myeong-Ki; Kim, Byeong-Keuk; Jang, Yangsoo; Kim, Hyo-Soo; Park, Kyung Woo; Gilard, Martine; Morice, Marie-Claude; Sawaya, Fadi; Sardella, Gennaro; Genereux, Philippe; Redfors, Bjorn; Leon, Martin B; Bhatt, Deepak L; Stone, Gregg W; Colombo, Antonio

2016-10-25

Optimal upfront dual antiplatelet therapy (DAPT) duration after complex percutaneous coronary intervention (PCI) with drug-eluting stents (DES) remains unclear. This study investigated the efficacy and safety of long-term (≥12 months) versus short-term (3 or 6 months) DAPT with aspirin and clopidogrel according to PCI complexity. The authors pooled patient-level data from 6 randomized controlled trials investigating DAPT durations after PCI. Complex PCI was defined as having at least 1 of the following features: 3 vessels treated, ≥3 stents implanted, ≥3 lesions treated, bifurcation with 2 stents implanted, total stent length >60 mm, or chronic total occlusion. The primary efficacy endpoint was major adverse cardiac events (MACE), defined as the composite of cardiac death, myocardial infarction, or stent thrombosis. The primary safety endpoint was major bleeding. Intention-to-treat was the primary analytic approach. Of 9,577 patients included in the pooled dataset for whom procedural variables were available, 1,680 (17.5%) underwent complex PCI. Overall, 85% of patients received new-generation DES. At a median follow-up time of 392 days (interquartile range: 366 to 710 days), patients who underwent complex PCI had a higher risk of MACE (adjusted hazard ratio [HR]: 1.98; 95% confidence interval [CI]: 1.50 to 2.60; p < 0.0001). Compared with short-term DAPT, long-term DAPT yielded significant reductions in MACE in the complex PCI group (adjusted HR: 0.56; 95% CI: 0.35 to 0.89) versus the noncomplex PCI group (adjusted HR: 1.01; 95% CI: 0.75 to 1.35; p interaction  = 0.01). The magnitude of the benefit with long-term DAPT was progressively greater per increase in procedural complexity. Long-term DAPT was associated with increased risk for major bleeding, which was similar between groups (p interaction  = 0.96). Results were consistent by per-treatment landmark analysis. Alongside other established clinical risk factors, procedural complexity is an important parameter to take into account in tailoring upfront duration of DAPT. Copyright © 2016 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Computational Analysis on Stent Geometries in Carotid Artery: A Review

NASA Astrophysics Data System (ADS)

Paisal, Muhammad Sufyan Amir; Taib, Ishkrizat; Ismail, Al Emran

2017-01-01

This paper reviews the work done by previous researchers in order to gather the information for the current study which about the computational analysis on stent geometry in carotid artery. The implantation of stent in carotid artery has become popular treatment for arterial diseases of hypertension such as stenosis, thrombosis, atherosclerosis and embolization, in reducing the rate of mortality and morbidity. For the stenting of an artery, the previous researchers did many type of mathematical models in which, the physiological variables of artery is analogized to electrical variables. Thus, the computational fluid dynamics (CFD) of artery could be done, which this method is also did by previous researchers. It lead to the current study in finding the hemodynamic characteristics due to artery stenting such as wall shear stress (WSS) and wall shear stress gradient (WSSG). Another objective of this study is to evaluate the nowadays stent configuration for full optimization in reducing the arterial side effect such as restenosis rate after a few weeks of stenting. The evaluation of stent is based on the decrease of strut-strut intersection, decrease of strut width and increase of the strut-strut spacing. The existing configuration of stents are actually good enough in widening the narrowed arterial wall but the disease such as thrombosis still occurs in early and late stage after the stent implantation. Thus, the outcome of this study is the prediction for the reduction of restenosis rate and the WSS distribution is predicted to be able in classifying which stent configuration is the best.

Stent Implantation for Superior Vena Cava Syndrome of Malignant Cause.

PubMed

Büstgens, Felix A; Loose, Reinhard; Ficker, Joachim H; Wucherer, Michael; Uder, Michael; Adamus, Ralf

2017-05-01

Purpose  The purpose of this paper is the retrospective analysis of endovascular therapy for the treatment of superior vena cava syndrome (SVCS) of malignant cause. This study focuses on the effectiveness of the therapy regarding the duration of remission, symptom control and practicability. Materials and Methods  From January 2003 to November 2012, therapeutic implantation of one or more stents was performed in 141 patients suffering from SVCS. The medical history was retrospectively researched using digitalized patient files. If those were incomplete, secondary research was conducted using the cancer registry of the General Hospital Nuremberg, the cancer registry of the tumor center at Friedrich-Alexander-University Erlangen-Nuremberg (FAU) or information given by physicians in private practice. This data was collected using Microsoft Office Excel ® and statistically analyzed using IBM SPSS Statistics 22 ® . Results  168 stents were implanted in 141 patients (median age: 64.6 years; range: 36 - 84), 86 being male and 55 being female. In 121 patients, SVCS was caused by lung cancer (85.8 %), in 9 patients by mediastinal metastasis of an extrathoracic carcinoma (6.4 %), in 3 patients by mesothelioma of the pleura (2.1 %) and in 1 patient by Hodgkin's disease (0.7 %). There was no histological diagnosis in 7 cases (4.9 %). The primary intervention was successful in 138 patients (97.9 %). Immediate thrombosis in the stent occurred in the remaining 3 cases. Recurrence of SVCS was observed in 22 patients (15.6 %), including 5 early and 17 late occlusions. Stent dislocation or breakage was not observed. As expected, the survival after implantation was poor. The median survival was 101 days, and the median occlusion-free survival was 80 days. Conclusion  The symptomatic therapy of SVCS with endovascular stents is effective and safe. Despite effective symptom control and a low rate of recurrence, the patients' prognosis is poor. Key Points:   · Patients with SVCS of malignant cause have a poor prognosis.. · Lung cancer is the most common cause for SVCS.. · Endovascular therapy is safe and effective.. Citation Format · Büstgens FA, Loose R, Ficker JH et al. Stent Implantation for Superior Vena Cava Syndrome of Malignant Cause. Fortschr Röntgenstr 2017; 189: 423 - 430. © Georg Thieme Verlag KG Stuttgart · New York.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parthipun, Aneeta; Diamantopoulos, Athanasios; Kitrou, Panagiotis

PurposeTo report the immediate and mid-term clinical and anatomical outcomes of a novel, hybrid, heparin-bonded, nitinol ring stent (TIGRIS; Gore Medical) when used for the treatment of lesions located in the popliteal artery.Materials and MethodsThis was a prospective single-centre registry. Patients eligible for inclusion were individuals suffering from symptomatic popliteal arterial occlusive disease (Rutherford–Becker stage 3–6; P1–P3 segments) and treated with placement of the TIGRIS stent(s). Patients were prospectively scheduled for clinical review and duplex ultrasound follow-up after 6 and 12 months. Outcome measures included immediate technical success, primary vessel patency, in-stent binary restenosis (evaluable by Duplex at 50 % threshold; PSVRmore » > 2.0), freedom from target lesion revascularization (TLR) and amputation-free survival (AFS) estimated by Kaplan–Meier (K–M) survival analysis. Cox proportional-hazards regression analysis was also performed to adjust for confounders and search for independent predictors of outcomes.ResultsFrom August 2012 to March 2014, a total of 54 popliteal TIGRIS stents were implanted in 50 limbs of 48 patients (27 men and 21 women; mean age 76.0 ± 1.7 years). Median Rutherford–Becker stage was five at baseline and 37/50 (74.0 %) were chronic total occlusions. Technical success was achieved in all cases (100 %). Stented lesion length was 114.2 ± 36.9 mm (range 6–20 cm). Median follow-up was 11.8 ± 0.8 months. After 12 months, primary patency of the TIGRIS stent was 69.5 ± 10.2 % with an 86.1 ± 5.9 % freedom from TLR and 87 ± 5.0 % AFS (K–M estimates).ConclusionThe TIGRIS hybrid heparin-bonded nitinol ring stent is a safe and effective endovascular option for complex occlusive disease of the popliteal artery.« less

Stent fracture, valve dysfunction, and right ventricular outflow tract reintervention after transcatheter pulmonary valve implantation: patient-related and procedural risk factors in the US Melody Valve Trial.

PubMed

McElhinney, Doff B; Cheatham, John P; Jones, Thomas K; Lock, James E; Vincent, Julie A; Zahn, Evan M; Hellenbrand, William E

2011-12-01

Among patients undergoing transcatheter pulmonary valve (TPV) replacement with the Melody valve, risk factors for Melody stent fracture (MSF) and right ventricular outflow tract (RVOT) reintervention have not been well defined. From January 2007 to January 2010, 150 patients (median age, 19 years) underwent TPV implantation in the Melody valve Investigational Device Exemption trial. Existing conduit stents from a prior catheterization were present in 37 patients (25%, fractured in 12); 1 or more new prestents were placed at the TPV implant catheterization in 51 patients. During follow-up (median, 30 months), MSF was diagnosed in 39 patients. Freedom from a diagnosis of MSF was 77±4% at 14 months (after the 1-year evaluation window) and 60±9% at 39 months (3-year window). On multivariable analysis, implant within an existing stent, new prestent, or bioprosthetic valve (combined variable) was associated with longer freedom from MSF (P<0.001), whereas TPV compression (P=0.01) and apposition to the anterior chest wall (P=0.02) were associated with shorter freedom from MSF. Freedom from RVOT reintervention was 86±4% at 27 months. Among patients with a MSF, freedom from RVOT reintervention after MSF diagnosis was 49±10% at 2 years. Factors associated with reintervention were similar to those for MSF. MSF was common after TPV implant in this multicenter experience and was more likely in patients with severely obstructed RVOT conduits and when the TPV was directly behind the anterior chest wall and/or clearly compressed. A TPV implant site protected by a prestent or bioprosthetic valve was associated with lower risk of MSF and reintervention.

Radioactive self-expanding stents for palliative management of unresectable esophageal cancer: a systematic review and meta-analysis.

PubMed

Chen, Hong-Lin; Shen, Wang-Qin; Liu, Kun

2017-05-01

Stent insertion is a feasible and safe palliative management for advanced unresectable esophageal cancer. The aim of this study is to assess the efficacy of radioactive stent for unresectable esophageal cancer compared with conventional stent. Systematic searches of the PubMed and Web of science are dated from their beginning to January 25, 2016. Studies that compared radioactive stent with conventional stent for unresectable esophageal cancer were included. The outcomes were postimplantation survival, relief of dysphagia, and complications related to stent implant. Six studies with 539 patients were included. All of them used stent equipped with radioactive iodine beads as a radioactive stent. The pooled weighted mean difference for median survival was 2.734 months (95% CI 1.710-3.775; Z = 5.21, P = 0.000) between two groups. The 1,3,6 month survival rates were higher in radioactive stents than conventional stent, with the pooled ORs 3.216 (95% CI 1.293-7.999; Z = 2.51, P = 0.012), 3.095 (95% CI 1.908-5.020; Z = 4.58, P = 0.000), and 7.503 (95% CI 2.206- 25.516; Z = 3.23, P = 0.001, respectively). The pooled hazard ratio was 0.464 (95% CI 0.328-0.655; Z = 4.35, P = 0.000) between two groups. For relief of dysphagia, two stents all have good relief of the dysphagia effect, but radioactive stent showed a better effect at 3, 6 months follow-up after implantation. For complications related to stent implant, no significant differences were found between two stents in terms of severe chest pain (30.0% vs. 35.7%, OR 0.765, 95% CI 0.490-1.196), gastroesophageal reflux (18.6% vs. 16.1%, OR 1.188, 95% CI 0.453-3.115), fever (12.1% vs. 12.1%, OR 1.014, 95% CI 0.332-3.097), bleeding (16.7% vs. 14.2%, OR 1.201, 95% CI 0.645-2.236), perforation or fistula (6.1% vs. 9.0%, OR 0.658, 95% CI 0.291-1.486), pneumonia (10.7% vs. 14.1%, OR 0.724, 95% CI 0.343-1.526), stent migration (7.0% vs. 10.2%, OR 0.651, 95% CI 0.220-1.924), and restenosis (24.2% vs. 20.6%, OR 1.228, 95% CI 0.674-2.239). Radioactive stent insertion had potential benefits for palliative management for patients with unresectable esophageal cancer. This method prolonged survival and dysphagia relief period without more complications. However, this conclusion should be confirmed by more trials. © International Society for Diseases of the Esophagus 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Absorbable magnesium-based stent: physiological factors to consider for in vitro degradation assessments

PubMed Central

Wang, Juan; Smith, Christopher E.; Sankar, Jagannathan; Yun, Yeoheung; Huang, Nan

2015-01-01

Absorbable metals have been widely tested in various in vitro settings using cells to evaluate their possible suitability as an implant material. However, there exists a gap between in vivo and in vitro test results for absorbable materials. A lot of traditional in vitro assessments for permanent materials are no longer applicable to absorbable metallic implants. A key step is to identify and test the relevant microenvironment and parameters in test systems, which should be adapted according to the specific application. New test methods are necessary to reduce the difference between in vivo and in vitro test results and provide more accurate information to better understand absorbable metallic implants. In this investigative review, we strive to summarize the latest test methods for characterizing absorbable magnesium-based stent for bioabsorption/biodegradation behavior in the mimicking vascular environments. Also, this article comprehensively discusses the direction of test standardization for absorbable stents to paint a more accurate picture of the in vivo condition around implants to determine the most important parameters and their dynamic interactions. PMID:26816631

Experimental evaluation of efficacy and healing response of everolimus-eluting stents in the familial hypercholesterolemic swine model: a comparative study of bioabsorbable versus durable polymer stent platforms.

PubMed

Tellez, Armando; Seifert, Paul S; Donskoy, Elina; Sushkova, Natalia; Pennington, Douglas E; Milewski, Krzysztof; Krueger, Christian G; Kaluza, Greg L; Eppihimer, Michael J; Huibregtse, Barbara A; Dawkins, Keith D; Granada, Juan F

2014-05-01

The utility of animal models for the prediction of drug-eluting stent (DES) efficacy in human clinical trials is still unclear. The familial hypercholesterolemic swine (FHS) model has been shown to induce a human-like neointimal response to bare metal stent (BMS) implantation. However, its utility to discriminate efficacy signals following DES implantation is unknown. In this study, we aimed to test the efficacy and healing response of several everolimus-eluting stent (EES) platforms in the coronary territory of the FHS. A total of 19 EES platforms (SYNERGY=6, SYNERGY½-dose=7, and PROMUS Element=6) and an identical BMS control (Element=6) were implanted into the coronary arteries of nine FHS. All implants were performed under intravascular ultrasound guidance using a 1.2 : 1 overstretch ratio. At 30 days, the vascular response to the implant was evaluated by quantitative coronary angiography, optical coherence tomography, and histology. At 28 days, all EES platforms showed a significant decrease in angiographic late lumen loss (between 27 and 37%) compared with the BMS control group. This finding was confirmed both by optical coherence tomography (mean neointimal thickness=28-42% reduction) and by histology (mean neointimal thickness=44-55% reduction). All EES platforms showed similar degrees of neointimal inhibition. The presence of moderate to severe para-strut inflammation was observed in 83% of the stent sections in the BMS group compared with 28.6% in the SYNERGY½-dose group and 0% in the SYNERGY and PROMUS groups (P=0.0002). There was a 68-95% reduction in MMP9 expression in the media in all EES platforms compared with the BMS controls. The presence of mild to moderate para-strut fibrin deposits ranged from 66.7 to 83.4% in all EES platforms compared with 16.7% in the EBMS group. The FHS coronary injury model showed the efficacy of several EES platforms compared with an identical BMS control. Everolimus eluted from different polymeric platforms showed lower levels of inflammation and slightly higher fibrin deposits compared with BMS controls.

Combining clinical and angiographic variables for estimating risk of target lesion revascularization after drug eluting stent placement.

PubMed

Stolker, Joshua M; Cohen, David J; Kennedy, Kevin F; Pencina, Michael J; Arnold, Suzanne V; Kleiman, Neal S; Spertus, John A

Drug-eluting stents (DES) reduce restenosis but require prolonged antiplatelet therapy, when compared with bare metal stents. Ideally, the patient should be involved in this risk:benefit assessment prior to selecting DES, to maximize the benefits and cost-effectiveness of care, and to improve medication adherence. However, accurate estimation of restenosis risk may require angiographic factors identified at cardiac catheterization. In a large PCI registry, we used logistic regression to identify clinical and angiographic predictors of clinically-driven target lesion revascularization (TLR) over the first year after stent placement. Discrimination c-statistic and integrated discrimination improvement (IDI) were used to calculate the incremental utility of angiographic variables when added to clinical predictors. Of 8501 PCI patients, TLR occurred in 4.5%. After adjusting for DES use, clinical TLR predictors were younger age, female sex, diabetes, prior PCI, and prior bypass surgery (model c-statistic 0.630). Angiographic predictors were vein graft PCI, in-stent restenosis lesion, longer stent length, and smaller stent diameter (c-statistic 0.650). After adding angiographic factors to the clinical model, c-statistic improved to 0.680 and the average separation in TLR risk among patients with and without TLR improved by 1% (IDI=0.010, 95% CI 0.009-0.014), primarily driven by those experiencing TLR (from 5.9% to 6.9% absolute risk). Among unselected PCI patients, the incidence of clinically-indicated TLR is <5% at 1-year, and standard clinical variables only moderately discriminate who will and will not experience TLR. Angiographic variables significantly improve TLR risk assessment, suggesting that stent selection may be best performed after coronary anatomy has been delineated. Although several recent studies have challenged traditional expectations regarding the duration of dual antiplatelet therapy, current guidelines recommend at least 6 to 12months of treatment after implantation of a drug eluting stent, with a shorter course for bare metal stents. Stent selection ideally should involve input from the patient receiving these stents, but multiple studies have suggested that angiographic factors - obtained after the patient has received sedation during the diagnostic catheterization - are important predictors of repeat revascularization. In this analysis from a large registry of patients receiving coronary stents, angiographic characteristics were found to significantly improve risk assessment for target lesion revascularization, when added to clinical variables alone. Copyright © 2016 Elsevier Inc. All rights reserved.

Long-Term Outcomes of Stenting the Proximal Left Anterior Descending Artery in the PROTECT Trial.

PubMed

Roguin, Ariel; Camenzind, Edoardo; Kerner, Arthur; Beyar, Rafael; Boersma, Eric; Mauri, Laura; Steg, Ph Gabriel; Wijns, William

2017-03-27

This study sought to compare the outcomes of patients undergoing drug-eluting stent implantation according to lesion location within or outside the proximal left anterior descending (LAD) artery. Proximal LAD artery involvement is considered uniquely in revascularization guidelines. The impact of LAD lesion location on long-term outcomes after revascularization is poorly understood in context of current percutaneous coronary intervention and medical therapy. Among 8,709 patients enrolled in PROTECT (Patient Related Outcomes with Endeavor Versus Cypher Stenting Trial), a multicenter percutaneous coronary intervention trial, we compared the outcomes of 2,534 patients (29.1%) (3,871 lesions [31.5%]) with stents implanted in the proximal LAD to 6,172 patients (70.9%) (8,419 lesions [68.5%]) with stents implanted outside the proximal LAD. At the 4-year follow-up, death rates were the same (5.8% vs. 5.8%; p > 0.999), but more myocardial infarctions occurred in the proximal LAD group (6.2% vs. 4.9%; p = 0.015). The rate of clinically driven target vessel failure (TVF) (14.8% vs. 13.5%; p = 0.109), major adverse cardiac event(s) (MACE) (15.0% vs. 13.7%; hazard ratio: 1.1; 95% confidence interval: 0.97 to 1.31; p = 0.139), and stent thrombosis (2.1% vs. 2.0%; p = 0.800) were similar. Drug-eluting stent type had no interaction with MACE or TVF. In multivariate analysis, the proximal LAD was a predictor of myocardial infarction (p = 0.038) but not of TVF (p = 0.149) or MACE (p = 0.069). In this study of contemporary percutaneous coronary intervention, proximal LAD location was associated with higher rates of myocardial infarction during the long-term follow-up, but there were no differences in stent thrombosis, death, TVF, or overall MACE. This finding may suggest that, in the drug-eluting stent era, proximal LAD no longer confers a different prognosis than other lesion sites. (Randomized Study Comparing Endeavor With Cypher Stents [PROTECT]; NCT00476957). Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Initial Clinical Experience with an Endoluminal Spiral Prosthesis for Treating Complicated Venous Thrombosis and Preventing Pulmonary Embolism

PubMed Central

Jakob, H.; Oelert, H.; Schmiedt, W.; Teusch, P.; Iversen, S.; Hake, U.; Schild, H.; Maass, D.

1989-01-01

Fourteen patients with complicated venous thrombosis or recurrent pulmonary embolism were treated by implantation of an endoluminal spiral prosthesis subsequent to balloon angioplasty, surgical thrombectomy or embolectomy, a combination of these, or, in 2 cases, no other treatment. The patients were divided into 2 groups, based on their primary diagnosis and the purpose of the prosthesis. Group I included 8 patients with extensive iliofemoral or caval thrombosis, caused by congenital caval stenosis (1 case) or extravascular compression or retraction (7 cases); 7 of these patients had had previous operations, and the remaining patient had undergone thrombolysis, which failed. The current treatment consisted of balloon angioplasty and surgical thrombectomy or embolectomy, and implantation of an endoluminal spiral stent to prevent elastic recoil of the vessel. In 4 cases, an arteriovenous fistula was constructed and was taken down 3 months later; in 1 additional patient, a bilateral arteriovenous fistula was created. Group II comprised 6 patients with recurrent pulmonary embolism (4 cases), massive pulmonary embolism (1 case), or paradoxical bilateral carotid artery embolism (1 case). Four of these patients underwent surgical thrombectomy or embolectomy, while 2 had no treatment other than filter implantation. All 6 underwent transluminal implantation of a helix caval filter (a modification of the endoluminal spiral stent). All but 1 implantation was accomplished by means of either a transfemoral or a transjugular cutdown; the remaining implantation was performed transatrially after a pulmonary embolectomy. The only device-related complication was a retroperitoneal hematoma in Group I, resulting from perforation of the inferior vena cava by the guidewire during device implantation. This complication necessitated an emergency laparotomy and takedown of the arteriovenous fistula, which resulted in rethrombosis of the left iliofemoral vein. The other 7 stented veins were patent at early phlebographic follow-up, as were all 5 of those studied later. One Group-I patient died 4 months after surgery, due to tumor progression and without signs of caval restenosis. Twelve months postoperatively, 1 Group-II patient died of urosepsis without a recurrence of pulmonary embolism. Four of the 6 Group-II patients were studied late postoperatively, and all of their stented vessels were patent. There was no operative mortality or postoperative embolism. On the basis of these results, we conclude that endoluminal stenting with an expandable spiral prosthesis is a promising method for remote venous reconstruction. Moreover, it appears that the modified stent, or helix caval filter, compares favorably with commercially available filters. (Texas Heart Institute Journal 1989;16:87-94) Images PMID:15227219

Usefulness of Corsair microcatheter to cross stent struts in bifurcation lesions.

PubMed

Fujimoto, Yoshihide; Iwata, Yo; Yamamoto, Masashi; Kobayashi, Yoshio

2014-01-01

Side branch compromise after stenting in bifurcation lesions is a matter of concern. It may happen that even low-profile balloon catheters do not cross stent struts after rewiring. The Corsair catheter is a hybrid catheter that has features of a microcatheter and a support catheter. The present study evaluated usefulness of the Corsair catheter to facilitate advancing a low-profile balloon catheter through stent struts in bifurcation lesions. After rewiring, low-profile balloon catheters failed to cross stent struts of 29 bifurcation lesions. The Corsair microcatheter successfully crossed stent struts in all lesions except one (97 %) where a stent was implanted to treat in-stent restenosis (stent-in-stent). Low-profile balloon catheters were able to advance into the side branch of all bifurcation lesions where the Corsair microcatheter crossed stent struts. In conclusion, the Corsair microcatheter may be utilized if low-profile balloon catheters are unable to cross stent struts in bifurcation lesions.

Medical implants and methods of making medical implants

DOEpatents

Shaw, Wendy J; Yonker, Clement R; Fulton, John L; Tarasevich, Barbara J; McClain, James B; Taylor, Doug

2014-09-16

A medical implant device having a substrate with an oxidized surface and a silane derivative coating covalently bonded to the oxidized surface. A bioactive agent is covalently bonded to the silane derivative coating. An implantable stent device including a stent core having an oxidized surface with a layer of silane derivative covalently bonded thereto. A spacer layer comprising polyethylene glycol (PEG) is covalently bonded to the layer of silane derivative and a protein is covalently bonded to the PEG. A method of making a medical implant device including providing a substrate having a surface, oxidizing the surface and reacting with derivitized silane to form a silane coating covalently bonded to the surface. A bioactive agent is then covalently bonded to the silane coating. In particular instances, an additional coating of bio-absorbable polymer and/or pharmaceutical agent is deposited over the bioactive agent.

[Acute stent thrombosis and reverse transient left ventricular dilatation after performing a single-photon emission computed tomography myocardial perfusion].

PubMed

Miranda, B; Pizzi, M N; Aguadé-Bruix, S; Domingo, E; Candell-Riera, J

2015-01-01

A 63-year-old male patient with a history of stent implantation in the left anterior descending three months before. Due to the presentation of vegetative symptoms, he was referred for gated-SPECT myocardial perfusion. During acquisition of the resting images he presented chest pain and ST segment elevation, so that urgent cardiac catheterization was performed, showing stent thrombosis. Rest perfusion imaging showed a defect in anterior and apical perfusion, more severe and extensive than in the stress images, with striking left ventricular dilatation and a fall in the ejection fraction related to the acute ischemia phenomenon. Intense exercise is associated with a transient activation of the coagulation system and hemodynamic changes that might induce thrombosis, especially in recently implanted coronary stents that probably still have not become completely endothelialized. Copyright © 2014 Elsevier España, S.L.U. y SEMNIM. All rights reserved.

Technological Advances in Stent Therapies: a Year in Review.

PubMed

Raffoul, Jad; Nasir, Ammar; Klein, Andrew J P

2018-04-07

Stent technology has rapidly evolved since the first stainless steel bare metal stents with substantial developments in scaffolding, polymer, drug choice, drug delivery, and elution mechanisms. Most recently, there has been the evolution of bioabsorbable vascular scaffolds, potentially eliminating the need for long-term foreign object retention. These rapid developments have led to an ever-expanding selection of new stents, making the choice of which to use in which patient challenging. Operators must balance potential short- and long-term clinical ramifications, namely stent thrombosis, in-stent restenosis, target lesion revascularization, and target lesion failure. In this review, we hope to provide insight for interventional cardiologists on the details of stent technology and how this impacts outcomes, stent selection, and duration of dual-antiplatelet therapy duration post drug-eluting stent implantation.

Long-Term Primary Patency Rate After Nitinol Self-Expandable Stents Implantation in Long, Totally Occluded Femoropopliteal (TASC II C & D) Lesions.

PubMed

Elmahdy, Mahmoud Farouk; Buonamici, Piergiovanni; Trapani, Maurizio; Valenti, Renato; Migliorini, Angela; Parodi, Guido; Antoniucci, David

2017-06-01

Endovascular therapy for long femoropopliteal lesions using percutaneous transluminal balloon angioplasty or first-generation of peripheral stents has been associated with unacceptable one-year restenosis rates. However, with recent advances in equipment and techniques, a better primary patency rate is expected. This study was conducted to detect the long-term primary patency rate of nitinol self-expandable stents implanted in long, totally occluded femoropopliteal lesions TransAtlantic Inter-Society Census (TASC II type C & D), and determine the predictors of reocclusion or restenosis in the stented segments. The demographics, clinical, anatomical, and procedural data of 213 patients with 240 de novo totally occluded femoropopliteal (TASC II type C & D) lesions treated with nitinol self-expandable stents were retrospectively analysed. Of these limbs, 159 (66.2%) presented with intermittent claudication, while 81 (33.8%) presented with critical limb ischaemia. The mean-time of follow-up was 36±22.6 months, (range: 6.3-106.2 months). Outcomes evaluated were, primary patency rate and predictors of reocclusion or restenosis in the stented segments. The mean age of the patients was 70.9±9.3 years, with male gender 66.2%. Mean pre-procedural ABI was 0.45±0.53. One-hundred-and-seventy-five (73%) lesions were TASC II type C, while 65 (27%) were type D lesions. The mean length of the lesions was 17.9±11.3mm. Procedure related complications occurred in 10 (4.1%) limbs. There was no periprocedural mortality. Reocclusion and restenosis were detected during follow-up in 45 and 30 limbs respectively, and all were re-treated by endovascular approach. None of the patients required major amputation. Primary patency rates were 81.4±1.1%, 77.7±1.9% and 74.4±2.8% at 12, 24, and 36 months respectively. Male gender, severe calcification, and TASC II D lesion were independent predictors for reocclusion, while predictors of restenosis were DM, smoking and TASC II D lesions. Treatment of long, totally occluded femoropopliteal (TASC II C & D) lesions with nitinol self-expandable stents is safe and is associated with highly acceptable long-term primary patency rates. Copyright © 2016 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier B.V. All rights reserved.

Experimental Evaluation of a New Tubular Coronary Stent (V-Flexª).

PubMed

Shun; Wang; Zhou; Verbeken; Ping; Szilard; Yanming; Jianhua; De Scheerder IK

1998-11-01

The safety, efficacy, angiographic and histological effects of a new 316 L, SS seamless stainless steel tubular stent (V-Flexª, Global Therapeutics, Broomfield, Colorado) was evaluated in a porcine coronary and peripheral artery model. Implantation in the right coronary artery was successful in all 16 pigs. Eight pigs were angiographically controlled after 6 weeks and then sacrificed for morphometric analysis. All stented coronary vessels were widely patent at this moment and morphometric analysis showed only a mild fibromuscular neointimal hyperplasia resulting in a neointimal hyperplasia of 1.15 +/- 0.38 mm2. The remaining 8 pigs were controlled and sacrificed at 12 weeks. At that time, all stented vessels were patent and neointimal hyperplasia was 1.22 +/- 0.34 mm2. Comparison with the Palmaz-Schatzª coronary stent (Cordis, Miami, Florida) in a porcine peripheral artery model demonstrated significantly less neointimal hyperplasia at 6 weeks (1.11 +/- 0.73 vs. 2.40 +/- 0.36, p = 0.001) and at 12 weeks (1.53 +/- 0.42 vs. 2.47 +/- 0.63, p = 0.003) for the V-Flex stent. In conclusion, V-Flex coronary stent implantation in a porcine coronary and peripheral arteries results in a high procedural success rate without subacute thrombotic occlusions, despite no further anticoagulation nor antiplatelet therapy. Six and 12 week histopathological and morphometric evaluation demonstrated only a mild fibromuscular neointimal hyperplasia. Comparison with the Palmaz-Schatz coronary stent in a peripheral artery model showed significantly less neointimal hyperplasia in the V-Flex stent.

Experimental study of laminar blood flow through an artery treated by a stent implantation: characterisation of intra-stent wall shear stress.

PubMed

Benard, Nicolas; Coisne, Damien; Donal, Erwan; Perrault, Robert

2003-07-01

The stimulation of endothelial cells by arterial wall shear stress (WSS) plays a central role in restenosis. The fluid-structure interaction between stent wire and blood flow alters the WSS, particularly between stent struts. We have designed an in vitro model of struts of an intra-vascular prosthesis to study blood flow through a 'stented' section. The experimental artery consisted of a transparent square section test vein, which reproduced the strut design (100x magnifying power). A programmable pump was used to maintain a steady blood flow. Particle image velocimetry method was used to measure the flow between and over the stent branches, and to quantify WSS. Several prosthesis patterns that were representative of the total stent strut geometry were studied in a greater detail. We obtained WSS values of between -1.5 and 1.5Pa in a weak SS area which provided a source of endothelial stimulation propitious to restenosis. We also compared two similar patterns located in two different flow areas (one at the entry of the stent and one further downstream). We only detected a slight difference between the weakest SS levels at these two sites. As the endothelial proliferation is greatly influenced by the SS, knowledge of the SS modification induced by the stent implantation could be of importance for intra-vascular prostheses design optimisation and thus can help to reduce the restenosis incidence rate.

Preventive effects of 125I seeds on benign restenosis following esophageal stent implantation in a dog model

PubMed Central

GAN, ZHEN; JING, JIAN; ZHU, GUANGYU; QIN, YONGLIN; TENG, GAOJUN; GUO, JINHE

2015-01-01

The present study aimed to evaluate the effects of iodine-125 (125I) seeds on the proliferation of primary esophageal fibroblasts in dogs, and to assess the safety and preventive efficacy of 125I seed-pre-loaded esophageal stents in benign restenosis following implantation. Primary fibroblasts were cultured with various 125I seed activities, which were then evaluated using cell proliferation and apoptosis assays as well as cell cycle analysis using Annexin V/propidium iodide (PI) double staining and PI staining. Prior to sacrification, animals were submitted to esophageal radiography under digital subtraction angiography. Esophageal tissues were collected and examined for macroscopic, microscopic and pathological alterations. The results demonstrated a significant and dose-dependent inhibition of fibroblast proliferation and increased apoptosis following exposure to 125I seeds. G0/G1 fibroblast populations increased in a dose-dependent manner following treatment with 125I seeds, in contrast to cells in S phase. Four weeks following implantation, α-smooth muscle actin and proliferating cell nuclear antigen expression levels in the experimental group were significantly lower compared with those in the control group; in addition, eight weeks following implantation, esophageal inner diameters were increased in the experimental group. 125I seeds inhibited proliferation of dog esophageal fibroblasts via cell cycle arrest and apoptosis. In conclusion, 125I seed-pre-loaded esophageal stents inhibited benign hyperplasia in the upper edge of the stent to a certain extent, which relieved benign restenosis following implantation with a good safety profile. PMID:25543838

In vitro and in vivo cell-capture strategies using cardiac stent technology - A review.

PubMed

Ravindranath, Rohan R; Romaschin, Alexander; Thompson, Michael

2016-01-01

Stenosis is a symptom of coronary artery disease (CAD), and is caused by narrowing of arteries in the heart. Over the last several decades, medical implants such as cardiac stents have been developed to counter stenosis. Upon implantation of a stent to open up a restricted artery, narrowing of the artery can reoccur (restenosis), due to an immune response launched by the body towards the stent. Currently, restenosis is a major health concern for patients who have undergone heart surgery for coronary artery disease. Recently, there have been new methods developed to combat restenosis, which have shown potential signs of success. One proposed method is the use of stents to capture cells, thereby reducing immune response. This review will explore the different methods for cell capture both in vitro and in vivo. Biological modifications of the stent will be surveyed, as well as the use of surface science to immobilize biological probes. Immobilization of proteins and nucleotides, as well as use of magnetic field are all methods that will be further discussed. Finally, concluding remarks and future prospects will be presented. Copyright © 2015 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

Application of High Entropy Alloys in Stent Implants

NASA Astrophysics Data System (ADS)

Alagarsamy, Karthik

High entropy alloys (HEAs) are alloys with five or more principal elements. Due to these distinct concept of alloying, the HEA exhibits unique and superior properties. The outstanding properties of HEA includes higher strength/hardness, superior wear resistance, high temperature stability, higher fatigue life, good corrosion and oxidation resistance. Such characteristics of HEA has been significant interest leading to researches on these emerging field. Even though many works are done to understand the characteristic of these HEAs, very few works are made on how the HEAs can be applied for commercial uses. This work discusses the application of High entropy alloys in biomedical applications. The coronary heart disease, the leading cause of death in the United States kills more than 350,000 persons/year and it costs $108.9 billion for the nation each year in spite of significant advancements in medical care and public awareness. A cardiovascular disease affects heart or blood vessels (arteries, veins and capillaries) or both by blocking the blood flow. As a surgical interventions, stent implants are deployed to cure or ameliorate the disease. However, the high failure rate of stents has lead researchers to give special attention towards analyzing stent structure, materials and characteristics. Many works related to alternate material and/or design are carried out in recent time. This paper discusses the feasibility of CoCrFeNiMn and Al0.1CoCrFeNi HEAs in stent implant application. This work is based on the speculation that CoCrFeNiMn and Al0.1CoCrFeNi HEAs are biocompatible material. These HEAs are characterized to determine the microstructure and mechanical properties. Computational modeling and analysis were carried out on stent implant by applying CoCrFeNiMn and Al0.1CoCrFeNi HEAs as material to understand the structural behavior.

Late adverse events after implantation of sirolimus-eluting stent and bare-metal stent: long-term (5-7 years) follow-up of the Coronary Revascularization Demonstrating Outcome study-Kyoto registry Cohort-2.

PubMed

Natsuaki, Masahiro; Morimoto, Takeshi; Furukawa, Yutaka; Nakagawa, Yoshihisa; Kadota, Kazushige; Yamaji, Kyohei; Ando, Kenji; Shizuta, Satoshi; Shiomi, Hiroki; Tada, Tomohisa; Tazaki, Junichi; Kato, Yoshihiro; Hayano, Mamoru; Abe, Mitsuru; Tamura, Takashi; Shirotani, Manabu; Miki, Shinji; Matsuda, Mitsuo; Takahashi, Mamoru; Ishii, Katsuhisa; Tanaka, Masaru; Aoyama, Takeshi; Doi, Osamu; Hattori, Ryuichi; Kato, Masayuki; Suwa, Satoru; Takizawa, Akinori; Takatsu, Yoshiki; Shinoda, Eiji; Eizawa, Hiroshi; Takeda, Teruki; Lee, Jong-Dae; Inoko, Moriaki; Ogawa, Hisao; Hamasaki, Shuichi; Horie, Minoru; Nohara, Ryuji; Kambara, Hirofumi; Fujiwara, Hisayoshi; Mitsudo, Kazuaki; Nobuyoshi, Masakiyo; Kita, Toru; Kimura, Takeshi

2014-04-01

Late adverse events such as very late stent thrombosis (VLST) or late target-lesion revascularization (TLR) after first-generation sirolimus-eluting stents (SES) implantation have not been yet fully characterized at long term in comparison with those after bare-metal stent (BMS) implantation. Among 13 058 consecutive patients undergoing first percutaneous coronary intervention in the Coronary REvascularization Demonstrating Outcome study-Kyoto registry Cohort-2, 5078 patients were treated with SES only, and 5392 patients were treated with BMS only. During 7-year follow-up, VLST and late TLR beyond 1 year after SES implantation occurred constantly and without attenuation at 0.24% per year and at 2.0% per year, respectively. Cumulative 7-year incidence of VLST was significantly higher in the SES group than that in the BMS group (1.43% versus 0.68%, P<0.0001). However, there was no excess of all-cause death beyond 1 year in the SES group as compared with that in the BMS group (20.8% versus 19.6%, P=0.91). Cumulative incidences of late TLR (both overall and clinically driven) were also significantly higher in the SES group than in the BMS group (12.0% versus 4.1%, P<0.0001 and 8.5% versus 2.6%, P<0.0001, respectively), leading to late catch-up of the SES group to the BMS group regarding TLR through the entire 7-year follow-up (18.8% versus 25.2%, and 10.6% versus 10.2%, respectively). Clinical presentation as acute coronary syndrome was more common at the time of late SES TLR compared with early SES TLR (21.2% and 10.0%). Late catch-up phenomenon regarding stent thrombosis and TLR was significantly more pronounced with SES than that with BMS. This limitation should remain the target for improvements of DES technology.

From implant planning to surgical execution: an integrated approach for surgery in oral implantology.

PubMed

Chiarelli, Tommaso; Franchini, Federico; Lamma, Achille; Lamma, Evelina; Sansoni, Tommaso

2012-03-01

Using oral implantology software and transferring the preoperative planning into a stereolithographic model, prosthodontists can produce the related surgical guide. This procedure has some disadvantages: bone-supported stent invasiveness, lack of references due to scattering and non-negligible stereolithography cost. An alternative solution is presented that provides an ideal surgical stent (not invasive, precise, and cheap) as a result. This work focuses on the third phase of a fully 3D approach to oral implant planning, that starts by CT scanning a patient who wears a markers-equipped radiological stent, continues exploiting built-on-purpose preoperative planning software, and finishes producing the ideal surgical template. A 5-axes bur-equipped robot has been designed able to reproduce the milling vectors planned by the software. Software-robot interfacing has been achieved properly matching the stent reference frame and the software and robot coordinate systems. Invasiveness has been avoided achieving the surgical stent from the mucosa-supported radiological mask wax-up. Scattering is ignored because of the surgical stent independency from the bone structure radiography. Production cost has been strongly reduced by avoiding the stereolithographic model. Finally, software-robot interfacing precision has been validated comparing digitally a multi-marker base and its planning transfer. Average position and orientation errors (respectively 0.283 mm ± 0.073 mm and 1.798° ± 0.496°) were significantly better than those achieved using methods based on stereolithography (respectively, 1.45 mm ± 1.42 mm and 7.25° ± 2.67°, with a general best maximum translation discrepancy of about 1.1 mm). This paper describes the last step of a fully 3D approach in which implant planning can be done in a 3D environment, and the correct position, orientation and depth of the planned implants are easily computed and transferred to the surgical phase. Copyright © 2011 John Wiley & Sons, Ltd.

Dual Antiplatelet Therapy for 6 Months vs 12 Months After New-generation Drug-eluting Stent Implantation: Matched Analysis of ESTROFA-DAPT and ESTROFA-2.

PubMed

de la Torre Hernández, José M; Oteo Domínguez, Juan F; Hernández, Felipe; García Camarero, Tamara; Abdul-Jawad Altisent, Omar; Rivero Crespo, Fernando; Cascón, José D; Zavala, Germán; Gimeno, Federico; Arrebola Moreno, Antonio L; Andraka, Leire; Gómez Menchero, Antonio; Bosa, Francisco; Carrillo, Xavier; Sánchez Recalde, Ángel; Alfonso, Fernando; Pérez de Prado, Armando; López Palop, Ramón; Sanchis, Juan; Diarte de Miguel, José A; Jiménez Navarro, Manuel; Muñoz, Luz; Ramírez Moreno, Antonio; Tizón Marcos, Helena

2015-10-01

The recommendation for dual antiplatelet therapy following drug-eluting stent implantation ranges from 6 months to 12 months or beyond. Recent trials have suggested the safety of a 6-month dual antiplatelet therapy regimen, yet certain caveats to these studies limit the applicability of this shorter duration dual antiplatelet therapy strategy in real world settings. A registry was constructed with consecutive recruitment of patients undergoing new-generation drug-eluting stent implantation and prescribed 6 months of dual antiplatelet therapy. Propensity score matching was undertaken with a historical cohort of patients treated with second-generation drug-eluting stents who received 12 months of dual antiplatelet therapy from the ESTROFA-2 registry. The sample size was calculated using a noninferiority basis and the primary endpoint was the combination of cardiac death, myocardial infarction, revascularization, or major bleeding at 12 months. The analysis included 1286 patients in each group, with no significant differences in baseline characteristics. The primary endpoint occurred in 5.0% and 6.6% in the 6-month and 12-month groups, respectively (P = .001 for noninferiority). The incidence of definite or probable stent thrombosis was 0.5% and 0.7% in the 6-month and 12-month groups, respectively (P = .4). Major bleeding events were lower in the 6-month group than in the 12-month group (0.8% vs 1.4%; P = .2) CONCLUSIONS: In selected patients in this large multicenter study, the safety and efficacy of a 6-month dual antiplatelet therapy regimen after implantation of new-generation drug-eluting stents appeared to be noninferior to those of a 12-month dual antiplatelet therapy regimen. Copyright © 2015 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

Contralateral Deep Vein Thrombosis after Iliac Vein Stent Placement in Patients with May-Thurner Syndrome.

PubMed

Le, Trong Binh; Lee, Taeg Ki; Park, Keun-Myoung; Jeon, Yong Sun; Hong, Kee Chun; Cho, Soon Gu

2018-04-25

To investigate the incidence and potential causes of contralateral deep vein thrombosis (DVT) after common iliac vein (CIV) stent placement in patients with May-Thurner syndrome (MTS). Data of 111 patients (women: 73%) who had CIV stent implantation for symptomatic MTS at a single center were retrospectively analyzed. Mean patient age was 63.1 ± 15.2 years. Median follow-up was 36 months (range, 1-142 months). Stent location was determined by venogram and classified as extended to the inferior vena cava (IVC), covered the confluence, or confined to the iliac vein. Potential causes of contralateral DVT were presumed based on venographic findings. The relationship between stent location and contralateral DVT was analyzed. Ten patients (9%, men/women: 4/6) exhibited contralateral DVT at a median timing of 40 months (range, 6-98 months). Median age was 69 years (range, 42-85 years). Median follow-up was 73.5 months (range, 20-134 months). Potential causes were venous intimal hyperplasia (VIH) (n = 7), "jailing" (n = 2), and indeterminate (n = 1). All patients with VIH had previous CIV stents overextended to the IVC. Overextension of CIV stent was associated with contralateral DVT (P < .001). The primary patency rate of the contralateral CIV stent was 70% at 20 months. Contralateral DVT after CIV stent implantation has a relatively high incidence and often occurs late during follow-up. Overextension of the CIV stent to the IVC is associated with development of contralateral DVT, and VIH should be considered a potential cause. Copyright © 2018 SIR. Published by Elsevier Inc. All rights reserved.

[Significance of the level of implantation of the 'E-vita open plus' hybrid stent graft into the descending aorta in the development of spinal ischaemic complications].

PubMed

Kozlov, B N; Panfilov, D S; Saushkin, V V; Kuznetsov, M S; Nasrashvili, G G; Andriianova, A V; Shipulin, V M

Spinal ischaemia in patients after reconstruction of the thoracic aorta is referred to the category of the most severe postoperative complications, especially in hybrid interventions. The present study was aimed at assessing the risks for the development of spinal ischaemia in patients after implantation of the 'E-vita open plus' stent graft into the descending portion of the thoracic aorta during hybrid reconstruction. The 'E-vita open plus' hybrid stent graft (Jotec, Germany) was implanted to 18 patients presenting with various pathology of the thoracic aorta (dissection, aneurysms). All operations were carried out in the conditions of moderate hypothermia, circulatory arrest and antegrade perfusion of the brain through the brachiocephalic trunk. It was determined that the distal end of the stent graft was located at the level of Th7-Th12. In 12 (66.7%) cases the 'lower' edge of the stent graft was located at the level of thoracic vertebrae Th8-Th9. Before the operation the number of open pairs of intercostal arteries amounted to 10 [9, 11]. After the operation, the number of the open pairs of the segmental arteries amounted to 3 [1; 4], they were all in the lower thoracic portion; the above-located intercostal arteries were shut by the stent graft. In 17 (94.5%) cases in the early postoperative period there were no signs of spinal ischaemia. Only one (5.5%) patient was clinically diagnosed to have developed transient spinal ischaemia noted to disappear spontaneously within the first 24 hours. A conclusion was made that using the 'E-vita open plus' stent graft in the course of hybrid reconstruction of the thoracic aorta was accompanied by the minimal risk for spinal ischaemic complications. The level of the location of the distal edge of the stent graft is not the determining factor in the risks of spinal complications in of such similar operations.

Initial experience with the E-ventus® stent-graft for endovascular treatment of visceral artery aneurysms.

PubMed

Anton, Susanne; Stahlberg, Erik; Horn, Marco; Wiedner, Marcus; Kleemann, Markus; Barkhausen, Joerg; Goltz, Jan P

2018-04-01

To evaluate the safety and efficacy of a novel balloon-expandable stent-graft for endovascular treatment of visceral artery aneurysms (VAA). Between 9/2014 and 1/2017 seven patients (69±15 years) with true (N.=4) and false (N.=3) VAAs were treated by implantation of balloon-expandable stent-grafts (E-ventus®, Jotec, Hechingen, Germany) using a transfemoral (N.=2) or transbrachial (N.=5) vascular access. The stent-graft was placed without prior passing of the landing zone with a sheath. In 3 of 7 patients (42.9%) additional coil or plug embolization was performed to prevent retrograde VAA perfusion. Endpoints were technical success (defined as delivery and implantation of the stent-graft in the intended position with complete exclusion of the VAA), peri-procedural complications and patency. Mean diameters of true VAAs (splenic artery: N.=2, common hepatic artery: N.=1, celiac trunk: N.=1) were 26±9 and of false (common hepatic artery: N.=2, gastroduodenal artery: N.=1) 29±14 mm. False aneurysms presented as emergencies with active bleeding. Technical success was 100%. One peri-procedural complication was noted: pseudoaneurysm of the accessed brachial artery. After a mean follow-up of 187 days 6/7 stent-grafts (85.7%) were patent. One patient (fVAA) died two days after the emergency procedure owing to multi-organ failure which was assessed to be non-procedure-related. Another patient (fVAA) died 7 months from the procedure owing to cancer. Endovascular treatment of true and false visceral artery aneurysms by use of the E-ventus® stent-graft is safe and effective. Flexibility of the stent-graft and shaft allows for implantation without passing the lesion with a sheath, enabling treatment of distal as well as complex visceral lesions. Long-term results regarding patency in a larger patient cohort are needed to confirm these findings.

Long-term outcome after drug-eluting versus bare-metal stent implantation in patients with ST-segment elevation myocardial infarction: 5 years follow-up from the randomized DEDICATION trial (Drug Elution and Distal Protection in Acute Myocardial Infarction).

PubMed

Holmvang, Lene; Kelbæk, Henning; Kaltoft, Anne; Thuesen, Leif; Lassen, Jens Flensted; Clemmensen, Peter; Kløvgaard, Lene; Engstrøm, Thomas; Bøtker, Hans E; Saunamäki, Kari; Krusell, Lars R; Jørgensen, Erik; Tilsted, Hans-Henrik; Christiansen, Evald H; Ravkilde, Jan; Køber, Lars; Kofoed, Klaus Fuglsang; Terkelsen, Christian J; Helqvist, Steffen

2013-06-01

This study sought to compare the long-term effects of drug-eluting stent (DES) compared with bare-metal stent (BMS) implantation in patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention. The randomized DEDICATION (Drug Elution and Distal Protection in Acute Myocardial Infarction) trial evaluated the outcome after DES compared with BMS implantation in patients with STEMI undergoing primary percutaneous coronary intervention. Patients with a high-grade stenosis/occlusion of a native coronary artery presenting with symptoms <12 h and ST-segment elevation were enrolled after giving informed consent. Patients were randomly assigned to receive a DES or a BMS in the infarct-related lesion. Patients were followed for at least 5 years, and clinical endpoints were evaluated from population registries and hospital charts. The main endpoint was the occurrence of the first major adverse cardiac event (MACE), defined as cardiac death, nonfatal recurrent myocardial infarction, and target lesion revascularization. Complete clinical status was available in 623 patients (99.5%) at 5 years follow-up. The combined MACE rate was insignificantly lower in the DES group (16.9% vs. 23%), mainly driven by a lower need of repeat revascularization (p = 0.07). Whereas the number of deaths from all causes tended to be higher in the DES group (16.3% vs. 12.1%, p = 0.17), cardiac mortality was significantly higher (7.7% vs. 3.2%, p = 0.02). The 5-year stent thrombosis rates were generally low and similar between the DES and the BMS groups. No cardiac deaths occurring within 1 month could be clearly ascribed to stent thrombosis, whereas stent thrombosis was involved in 78% of later-occurring deaths. The 5-year MACE rate was insignificantly different, but the cardiac mortality was higher after DES versus BMS implantation in patients with STEMI. Stent thrombosis was the main cause of late cardiac deaths. Copyright © 2013 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Numerical simulation on the effects of drug eluting stents at different Reynolds numbers on hemodynamic and drug concentration distribution.

PubMed

Chen, Yu; Xiong, Yan; Jiang, Wentao; Yan, Fei; Guo, Meng; Wang, Qingyuan; Fan, Yubo

2015-01-01

The changes of hemodynamics and drug concentration distribution caused by the implantation of drug eluting stents (DESs) in curved vessels have significant effects on In-Stent Restenosis. A 3D virtual stent with 90° curvature was modelled and the distribution of wall shear stress (WSS) and drug concentration in this model were numerically studied at Reynolds numbers of 200, 400, 600, 800. The results showed that (1) the intensity of secondary flow at the 45° cross-section was stronger than that at the 90° cross-section; (2) As the Reynolds number increases, the WSS decreases. When the Reynolds number reaches 600, the low-WSS region only accounts for 3% of the total area. (3) The effects of Reynolds number on drug concentration in the vascular wall decreases in proportionally and then the blood velocity increased 4 times, the drug concentration in the vascular wall decreased by about 30%. (4) The size of the high drug concentration region is inversely proportional to the Reynolds number. As the blood velocity increases, the drug concentration in the DES decreases, especially at the outer bend. It is beneficial for the patient to decrease vigorous activities and keep calm at the beginning of the stent implantation, because a substantial amount of the drug is released in the first two months of stent implantation, thus a calm status is conducive to drug release and absorption; Subsequently, appropriate exercise which increases the blood velocity is helpful in decreasing regions of low-WSS.

Bare-metal stents across the Vater's ampulla is a safe method for patients with lower bile duct obstruction

PubMed Central

Mao, Xiao-Nan; Lu, Zai-Ming; Wen, Feng; Liang, Hong-Yuan; Guo, Qi-Yong

2017-01-01

Abstract This study explored the effect of the implant position of stents across the Vater's ampulla on treatment outcomes in patients with lower bile duct obstruction. In the retrospective study, 41 patients with malignant obstruction of the lower bile duct and obstructive jaundice received percutaneous transhepatic biliary placement of bare-metal stents. Basic demographic data on patients, such as sex, age, and primary diseases, and follow-up data, including postoperative complications and jaundice-free survival, were recorded. The follow-up data on patients with an involved ampulla, patients with an uninvolved ampulla, patients with a stent across the ampulla, and patients with a stent at a site other than the ampulla were compared. Furthermore, prognostic factors for jaundice- free survival were investigated using Cox proportional hazards regression analysis. Among the 41 patients, 38 patients experienced subsiding of jaundice, whereas 3 cases had unsuccessful stent patency. Whether or not the ampulla was involved did not influence the incidence rates of postoperative complications and the jaundice-free survival time. Notably, when stents were placed across the ampulla, the jaundice-free survival time was significantly longer than when stents were placed at sites other than across the ampulla (P < .05). Furthermore, placement of the stent across the ampulla or at other sites was an independent prognostic factor (hazard ratio = 0.154, 95% confidence interval 0.042–0.560, P = .005) for jaundice-free survival of patients. The current study revealed that the implant position of a stent across the ampulla resulted in maintenance of stent patency and prolongation of the jaundice-free survival time. PMID:29137005

A new intratracheal stent made from nitinol, an alloy with "shape memory effect".

PubMed

Vinograd, I; Klin, B; Brosh, T; Weinberg, M; Flomenblit, Y; Nevo, Z

1994-05-01

Temporary or permanent tracheal splinting in pediatric patients may be indicated in tracheomalacia or bronchomalacia, repair of congenital tracheal stenosis, and after tracheal resection. This study presents the results of the development of a new intraluminal airway stent made from titanium alloy, a metal with "shape memory effect". At low temperatures (martensitic state) the titanium alloy stent can be fashioned into a specific shape; then when heated to a higher temperature (austenitic state) the stent alters its shape, only to regain its original shape when recooled to the lower temperature. The stent, connected to a small electric power supply, was introduced into 20 young rabbits with the use of a 2.5 cm rigid bronchoscope. After implantation in the martensitic state the stent was warmed to 40 degrees C, the austenitic state, by an electric current of 1.5 to 3 ampere for 1 to 2 seconds. After a period of 8 to 10 weeks the stent was removed (in its martensitic state) through the same-sized bronchoscope after being cooled with 3 to 4 ml of 80% alcohol solution at 6 degrees C. No signs of airway obstruction developed in any of the animals after implantation or extraction of the stent. The biomechanical properties of the trachea, as shown by strain measurements with the use of incremental forces, showed significant differences between the stented and unstented segments (p < 0.005). The titanium alloy intratracheal stent adequately fulfilled the requirements of a temporary intraluminal airway splint, and because of its unique feature of shape memory effect the stent could be inserted, fixed, and removed easily, even in very small airways.

Chemical etching of nitinol stents.

PubMed

Katona, Bálint; Bognár, Eszter; Berta, Balázs; Nagy, Péter; Hirschberg, Kristóf

2013-01-01

At present the main cause of death originates from cardiovascular diseases. Primarily the most frequent cause is vessel closing thus resulting in tissue damage. The stent can help to avoid this. It expands the narrowed vessel section and allows free blood flow. The good surface quality of stents is important. It also must have adequate mechanical characteristics or else it can be damaged which can easily lead to the fracture of the implant. Thus, we have to consider the importance of the surface treatment of these implants. In our experiments the appropriate design was cut from a 1.041 mm inner diameter and 0.100 mm wall thickness nitinol tube by using Nd:YAG laser device. Then, the stent was subjected to chemical etching. By doing so, the burr created during the laser cutting process can be removed and the surface quality refined. In our research, we changed the time of chemical etching and monitored the effects of this parameter. The differently etched stents were subjected to microscopic analysis, mass measurement and in vivo environment tests. The etching times that gave suitable surface and mechanical features were identified.

Diabetes mellitus: a prothrombotic state Implications for outcomes after coronary revascularization

PubMed Central

Cola, Clarissa; Brugaletta, Salvatore; Yuste, Victoria Martín; Campos, Bieito; Angiolillo, Dominick J; Sabaté, Manel

2009-01-01

Coronary stent thrombosis is a serious problem in the drug-eluting stent era. Despite aggressive antiplatelet therapy during and after percutaneous coronary intervention (PCI), the incidence of sub-acute stent thrombosis remains approximately 0.5%–2%, which may represent a catastrophic clinical situation. Both procedural factors and discontinuation of antiplatelet therapy are normally associated with this event. We report on simultaneous stent thromboses of two drug-eluting stents implanted in two different vessels, which resulted in a life-threatening clinical condition. Possible contributing factors that led to synergistic thrombotic effects are discussed. PMID:19436654

Transradial primary angioplasty and stenting in Indian patients with acute myocardial infarction: acute results and 6-month follow-up.

PubMed

Ranjan, Alok; Patel, Tejas M; Shah, Sanjay C; Malhotra, Hemant; Patel, Rajni; Vayada, Nishith; Pothiwala, Rasesh; Fonseca, Keith; Tanwar, Narendra S

2005-01-01

Coronary angioplasty and stent implantation is effective as primary intervention in acute myocardial infarction. Because of fewer puncture site complications and improved patient comfort, transradial access has been increasingly used as an alternative to transfemoral access for percutaneous coronary interventions. We studied 103 patients (94 men, 9 women: mean age 52.5 +/- 11.96 years) with a diagnosis of acute myocardial infarction (<12 hours after onset), who underwent primary percutaneous coronary intervention. Transradial access was used in all patients with a normal Allen's test and transfemoral access was used additionally only if intra-aortic balloon counterpulsation was required. Follow-up duration was 6 months. Transradial access was successfully achieved in all patients. Radial artery cannulation took <2 min in more than 85% patients. During percutaneous coronary intervention, cannulation to balloon inflation times and total procedure times were 11.3 +/- 5.2 min and 19.9 +/- 10.8 min, respectively. Stents were implanted in 99 (96.1%) patients andplain balloon angioplastywas performed in 3.9%. The primary success rate was 98.1%, with no major bleeding complications. Total length of hospitalization averaged 2.4 +/- 0.8 days. In-hospital major adverse clinical events rate was 5.9%. Six-month clinical follow-up was achieved for 84 (86.6%) patients. Six (7.1%) patients died during follow-up. Follow-up coronary angiography was performed in 22 (26.2%) patients. After 6 months, 7 patients required revascularizationof the target lesion. The rate of survival without myocardial infarction, bypass surgery or repeat coronary angioplasty was 88.5% at 6 months. Transradial access may represent a safe and feasible technique for performing primary percutaneous coronary intervention with good acute results and without major bleeding complications.

The Primary Patency and Fracture Rates of Self-Expandable Nitinol Stents Placed in the Popliteal Arteries, Especially in the P2 and P3 Segments, in Korean Patients

PubMed Central

Chang, Il Soo; Park, Sang Woo; Yun, Ik Jin; Hwang, Jae Joon; Lee, Song Am; Kim, Jun Seok; Chang, Seong-Hwan; Jung, Hong Geun

2011-01-01

Objective We wanted to evaluate the status of self-expandable nitinol stents implanted in the P2 and P3 segments of the popliteal artery in Korean patients. Materials and Methods We retrospectively analyzed 189 consecutive patients who underwent endovascular treatment for stenoocclusive lesions in the femoropopliteal artery from July 2003 to March 2009, and 18 patients who underwent stent placement in popliteal arterial P2 and P3 segments were finally enrolled. Lesion patency was evaluated by ultrasound or CT angiography, and stent fracture was assessed by plain X-rays at 1, 3, 6 and 12 months and annually thereafter. Results At the 1-month follow-up, stent fracture (Type 2) was seen in one limb (up to P3, 1 of 18, 6%) and it was identified in seven limbs at the 3-month follow-up (Type 2, Type 3, Type 4) (n = 1: up to P2; n = 6: P3). At the 6-month follow-up, one more fracture (Type 1) (up to P3) was noted. At the 1-year follow-up, there were no additional stent fractures. Just four limbs (up to P2) at the 2-year follow-up did not have stent fracture. The primary patency was 94%, 61% and 44% at 1, 3 and 6 months, respectively, and the group with stent implantation up to P3 had a higher fracture rate than that of the group that underwent stenting up to P2 (p < 0.05). Conclusion We suggest that stent placement up to the popliteal arterial P3 segment and over P2 in an Asian population can worsen the stent patency owing to stent fracture. It may be necessary to develop a stent design and structure for the Asian population that can resist the bending force in the knee joint. PMID:21430937

Stent Implantation for Malignant Pulmonary Artery Stenosis in a Metastasizing Non-Small Cell Bronchial Carcinoma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gutzeit, A., E-mail: andreas.gutzeit@ksw.c; Koch, S.; Meier, U. R.

2008-07-15

A 58-year-old patient with recently diagnosed non-small cell bronchial carcinoma was referred to us with increasing shortness of breath and orthopnea by her family practitioner. To exclude the possibility of a pulmonary embolism, contrast medium-enhanced angio-CT of the thorax was performed. This showed a large mediastinal tumor, which, on the one hand, infiltrated and occluded the left upper lobe bronchus and, on the other, constricted the left pulmonary artery over a considerable part of its length. In view of the palliative situation and massively increasing dyspnea, balloon dilatation of the obstructed left pulmonary artery followed by stent placement was performed.more » This resulted in an immediate improvement of the symptoms. The originally strongly oxygen-dependent and heavily dyspneic patient could be relieved of the external supply of oxygen and was able to sleep normally without additional medication within 24 h. The patient was able ambulate freely within 2 days, with a markedly improved quality of life.« less

Intravascular Ultrasound and Angiographic Predictors of In-Stent Restenosis of Chronic Total Occlusion Lesions.

PubMed

Kang, Jeehoon; Cho, Young-Seok; Kim, Seong-Wook; Park, Jin Joo; Yoon, Yeonyee E; Oh, Il-Young; Yoon, Chang-Hwan; Suh, Jung-Won; Youn, Tae-Jin; Chae, In-Ho; Choi, Dong-Ju

2015-01-01

Despite the benefits of successful percutaneous coronary interventions (PCIs) for chronic total occlusion (CTO) lesions, PCIs of CTO lesions still carry a high rate of adverse events, including in-stent restenosis (ISR). Because previous reports have not specifically investigated the intravascular ultrasound (IVUS) predictors of ISR in CTO lesions, we focused on these predictors. We included 126 patients who underwent successful PCIs, using drug-eluting stents, and post-PCI IVUS of CTO lesions. Patient and lesion characteristics were analyzed to elucidate the ISR predictors. In each lesion, an average of 1.7 ± 0.7 (mean length, 46.4 ± 20.3 mm) stents were used. At 9 months follow-up, 14 (11%) patients demonstrated ISR, and 8 (6.3%) underwent target lesion revascularization. Multivariate logistic regression analysis showed that the independent predictors of ISR were the post-PCI minimal luminal diameter (MLD) and the stent expansion ratio (SER; minimal stent cross-sectional area (CSA) over the nominal CSA of the implanted stent), measured using quantitative coronary angiography (QCA) and IVUS, respectively. A receiver operating characteristic analysis indicated that the best post-PCI MLD and SER cut-off values for predicting ISR were 2.4 mm (area under the curve [AUC], 0.762; 95% confidence interval (CI), 0.639-0.885) and 70% (AUC, 0.714; 95% CI, 0.577-0.852), respectively. Lesions with post-PCI MLD and SER values less than these threshold values were at a higher risk of ISR, with an odds ratio of 23.3 (95% CI, 2.74-198.08), compared with lesions having larger MLD and SER values. Thus, the potential predictors of ISR, after PCI of CTO lesions, are the post-PCI MLD and SER values. The ISR rate was highest in lesions with a post-PCI MLD ≤2.4 mm and an SER ≤70%.

Use of Self-Expanding Metallic Ureteral Stents in the Secondary Treatment of Ureteral Stenosis Following Kidney Transplantation.

PubMed

Xu, Guibin; Li, Xun; He, Yongzhong; Zhao, Haibo; Yang, Weiqing; Xie, Qingling

2015-10-01

To evaluate the safety and efficacy of self-expanding metal stents in the treatment of ureteral stenosis following kidney transplantation. Seven patients who developed benign stenosis after kidney transplantation were treated by a self-expanding metallic stent implantation from June 2007 to March 2014. All patients had undergone at least one open surgical procedure and one endourologic procedure for treatment of the stenosis. The extent of stenosis varied from 1.2 to 3.7 cm. Ultrasonography, urography, diuretic renography, and urine culture were performed every 3 months after stent insertion. Ureteroscopic examination was performed when needed. Stent placement was technically effective in all cases. The mean operative time was 37 minutes (range, 26-59 minutes). Lower urinary-tract symptoms and the ipsilateral flank pain were common early-stage complications and were greatly relieved after an average of 3 months. The mean follow-up duration was 38 months (range, 13-86 months), and no stent migration or fragmentation was observed. Urothelial hyperplasia occurred in only one patient and was effectively managed with a Double-J stent. Five patients had normal stable renal function; the remaining two had impaired renal function, including one patient with a preoperative renal failure who required dialysis at the end of the follow-up period (36 months). As an alternative to open surgery, implantation of a self-expanding metal stent is a safe and effective treatment for ureteral stenosis in patients who have undergone kidney transplantation.

Flow modification in canine intracranial aneurysm model by an asymmetric stent: studies using digital subtraction angiography (DSA) and image-based computational fluid dynamics (CFD) analyses

NASA Astrophysics Data System (ADS)

Hoi, Yiemeng; Ionita, Ciprian N.; Tranquebar, Rekha V.; Hoffmann, Kenneth R.; Woodward, Scott H.; Taulbee, Dale B.; Meng, Hui; Rudin, Stephen

2006-03-01

An asymmetric stent with low porosity patch across the intracranial aneurysm neck and high porosity elsewhere is designed to modify the flow to result in thrombogenesis and occlusion of the aneurysm and yet to reduce the possibility of also occluding adjacent perforator vessels. The purposes of this study are to evaluate the flow field induced by an asymmetric stent using both numerical and digital subtraction angiography (DSA) methods and to quantify the flow dynamics of an asymmetric stent in an in vivo aneurysm model. We created a vein-pouch aneurysm model on the canine carotid artery. An asymmetric stent was implanted at the aneurysm, with 25% porosity across the aneurysm neck and 80% porosity elsewhere. The aneurysm geometry, before and after stent implantation, was acquired using cone beam CT and reconstructed for computational fluid dynamics (CFD) analysis. Both steady-state and pulsatile flow conditions using the measured waveforms from the aneurysm model were studied. To reduce computational costs, we modeled the asymmetric stent effect by specifying a pressure drop over the layer across the aneurysm orifice where the low porosity patch was located. From the CFD results, we found the asymmetric stent reduced the inflow into the aneurysm by 51%, and appeared to create a stasis-like environment which favors thrombus formation. The DSA sequences also showed substantial flow reduction into the aneurysm. Asymmetric stents may be a viable image guided intervention for treating intracranial aneurysms with desired flow modification features.

Intervention Therapy for Portal Vein Stenosis/Occlusion After Pediatric Liver Transplantation.

PubMed

Gao, Haijun; Wang, Hao; Chen, Guang; Yi, Zhengjia

2017-04-18

BACKGROUND The aim of this study was to investigate the outcomes and stent implantation timing of portal vein stenosis intervention after pediatric liver transplantation (pLT). MATERIAL AND METHODS The clinical data of 30 children with post-liver transplantation portal vein stenosis/occlusion (PVS/O) between Jan 2008 and Jun 2015 were retrospectively analyzed. The successfully re-opened cases used balloon angioplasty or stent implantation. SPSS13.0 software was used for statistical analysis and paired t test of the pressure gradient at both ends of the stenosis, diameter and flow rate within the stenosis, platelet count, and albumin in the PVS children before and after balloon angioplasty, with p<0.05 considered as statistically significant. Among the 30 patients, 6 received a stent implant in their first treatment, 22 received balloon angioplasty in their first treatment, and in 2 the re-opening could not be achieved. RESULTS The diameter of the stenotic segment, portal vein velocity, pressure gradient at both ends of the stenosis, and platelet count in these children with portal vein stenosis/occlusion (PVS/O) showed statistically significant differences when comparing values before and after intervention (p<0.05), but albumin showed no statistically significant difference (p>0.05). CONCLUSIONS Intervention therapy for portal vein stenosis after pediatric liver transplantation (pLT-PVS) is a safe and effective treatment, and patients with portal vein torsion, intimal tearing, or long portal vein segment occlusion should undergo stent implantation.

Expandable right ventricular-to-pulmonary artery conduit: an animal study.

PubMed

Boudjemline, Younes; Laborde, François; Pineau, Emmanuelle; Mollet, Alix; Abadir, Sylvia; Borenstein, Nicolas; Behr, Luc; Bonhoeffer, Philipp

2006-06-01

This study was performed to assess a new vascular stent graft as an expandable valved conduit for right ventricular outflow tract (RVOT) reconstruction in sheep. Conduits were constructed by sewing an 18-mm valved conduit inside a stent. Crimped to 16 mm, they were implanted either under or without extracorporeal circulation in seven (group A) and in five (group B) sheep, respectively. Six weeks and 3 mo after their insertion, conduits were dilated intraluminally. A valved stent was implanted percutaneously into conduits before they were killed. Two animals from group A recovered normally, whereas five animals had a complicated postoperative course. In group B, one died acutely due to kinking of the conduit. Balloon dilatations were performed in all surviving animals. First dilatations had a slight impact on valvular function in all animals but one, whereas second dilatations led to significant PR in all. Transcatheter valve implantation was performed successfully. When animals were killed, no bleeding was found around the surgically implanted device. In conclusion, we designed a biologic valved conduit for RVOT reconstruction that can be dilated sequentially to follow animal growth. This new device can have tremendous applications in children with congenital heart diseases involving the RVOT.

A Critical Review on Metallic Glasses as Structural Materials for Cardiovascular Stent Applications.

PubMed

Jafary-Zadeh, Mehdi; Praveen Kumar, Gideon; Branicio, Paulo Sergio; Seifi, Mohsen; Lewandowski, John J; Cui, Fangsen

2018-02-27

Functional and mechanical properties of novel biomaterials must be carefully evaluated to guarantee long-term biocompatibility and structural integrity of implantable medical devices. Owing to the combination of metallic bonding and amorphous structure, metallic glasses (MGs) exhibit extraordinary properties superior to conventional crystalline metallic alloys, placing them at the frontier of biomaterials research. MGs have potential to improve corrosion resistance, biocompatibility, strength, and longevity of biomedical implants, and hence are promising materials for cardiovascular stent applications. Nevertheless, while functional properties and biocompatibility of MGs have been widely investigated and validated, a solid understanding of their mechanical performance during different stages in stent applications is still scarce. In this review, we provide a brief, yet comprehensive account on the general aspects of MGs regarding their formation, processing, structure, mechanical, and chemical properties. More specifically, we focus on the additive manufacturing (AM) of MGs, their outstanding high strength and resilience, and their fatigue properties. The interconnection between processing, structure and mechanical behaviour of MGs is highlighted. We further review the main categories of cardiovascular stents, the required mechanical properties of each category, and the conventional materials have been using to address these requirements. Then, we bridge between the mechanical requirements of stents, structural properties of MGs, and the corresponding stent design caveats. In particular, we discuss our recent findings on the feasibility of using MGs in self-expandable stents where our results show that a metallic glass based aortic stent can be crimped without mechanical failure. We further justify the safe deployment of this stent in human descending aorta. It is our intent with this review to inspire biodevice developers toward the realization of MG-based stents.

A Critical Review on Metallic Glasses as Structural Materials for Cardiovascular Stent Applications

PubMed Central

Jafary-Zadeh, Mehdi; Praveen Kumar, Gideon

2018-01-01

Functional and mechanical properties of novel biomaterials must be carefully evaluated to guarantee long-term biocompatibility and structural integrity of implantable medical devices. Owing to the combination of metallic bonding and amorphous structure, metallic glasses (MGs) exhibit extraordinary properties superior to conventional crystalline metallic alloys, placing them at the frontier of biomaterials research. MGs have potential to improve corrosion resistance, biocompatibility, strength, and longevity of biomedical implants, and hence are promising materials for cardiovascular stent applications. Nevertheless, while functional properties and biocompatibility of MGs have been widely investigated and validated, a solid understanding of their mechanical performance during different stages in stent applications is still scarce. In this review, we provide a brief, yet comprehensive account on the general aspects of MGs regarding their formation, processing, structure, mechanical, and chemical properties. More specifically, we focus on the additive manufacturing (AM) of MGs, their outstanding high strength and resilience, and their fatigue properties. The interconnection between processing, structure and mechanical behaviour of MGs is highlighted. We further review the main categories of cardiovascular stents, the required mechanical properties of each category, and the conventional materials have been using to address these requirements. Then, we bridge between the mechanical requirements of stents, structural properties of MGs, and the corresponding stent design caveats. In particular, we discuss our recent findings on the feasibility of using MGs in self-expandable stents where our results show that a metallic glass based aortic stent can be crimped without mechanical failure. We further justify the safe deployment of this stent in human descending aorta. It is our intent with this review to inspire biodevice developers toward the realization of MG-based stents. PMID:29495521

Double bifurcation optimization stent system technique for left main stenosis.

PubMed

Vassilev, D; Mateev, H; Alexandrov, A; Karamfiloff, K; Gil, R J

2014-12-01

We present a first-in-man case with implantation in culottes' fashion of two dedicated coronary bifurcation stents (BiOSS Lim) in distal left main stenosis. The immediate procedural and very short-term result was excellent. © 2014, Wiley Periodicals, Inc.

Comparison of haemodialysis patients and non-haemodialysis patients with respect to clinical characteristics and 3-year clinical outcomes after sirolimus-eluting stent implantation: insights from the Japan multi-centre post-marketing surveillance registry.

PubMed

Otsuka, Yoritaka; Ishiwata, Sugao; Inada, Tsukasa; Kanno, Hiroyuki; Kyo, Eisho; Hayashi, Yasuhiko; Fujita, Hiroshi; Michishita, Ichiro

2011-04-01

Long-term outcomes after sirolimus-eluting stent (SES) implantation in haemodialysis (HD) patients have remained controversial. We investigated the impact of HD on outcomes after SES implantation. We analysed the data on 2050 patients who underwent SES implantation in a multi-centre prospective registry in Japan. Three-year clinical outcomes were compared between the HD group (n = 106) and the non-haemodialysis (NH) group (n = 1944). At the 3-year clinical follow-up, the rates of unadjusted cardiac mortality (HD: 16.3 vs. NH: 2.3%) and target-lesion revascularization (TLR) (HD: 19.4 vs. NH: 6.6%) were significantly higher in the HD group than the NH group (P < 0.001). Although HD group had a numerically higher stent thrombosis rate, the difference in stent thrombosis between the two groups (HD: 2.0 vs. NH: 0.7%) did not reach statistical significance. Using Cox's proportional-hazard models with propensity score adjustment for baseline differences, the HD group had higher risks of TLR [HD: 16.3 vs. NH: 6.1%; hazard ratio, 2.83; 95% confidence interval (CI): 1.62-4.93, P = 0.0003] and cardiac death (HD: 12.3 vs. NH: 2.3%; hazard ratio, 5.51; 95% CI: 2.58-11.78, P < 0.0001). The consistent results of analyses, whether unadjusted or adjusted for other baseline clinical and procedural differences, identify HD as an independent risk factor for cardiac death and TLR. Percutaneous coronary intervention with SES in HD patients has a higher incidence of repeat revascularization and mortality compared with those in NH patients. Haemodialysis appears to be strongly associated with mortality and repeat revascularization even after SES implantation.

Combined Arterial Infusion and Stent Implantation Compared with Metal Stent Alone in Treatment of Malignant Gastroduodenal Obstruction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang Zhongmin, E-mail: wzm0722@hotmail.co; Chen Kemin, E-mail: ckm0722@hotmail.co; Gong Ju

Many patients with malignant gastroduodenal obstruction have an unresectable primary lesion and distant metastases, which may prompt palliative management to allow the patient to eat and to improve the quality of life. Intraluminal metallic stent implantation (MSI) under fluoroscopic guidance has been reported to be an effective option for symptomatic relief in these patients, with a good safety record. An alternative, dual interventional therapy (DIT), has been used during the last decade, in which prosthesis insertion is followed by intra-arterial chemotherapy via the tumor-feeding arteries. The aim of this study was to compare success rates, complication rates, and survival timemore » between MSI and DIT in patients who presented with gastroduodenal obstruction from advanced upper gastrointestinal tract cancer. All consecutive patients with malignant gastroduodenal obstruction seen at our center between October 2002 and August 2007 were retrospectively studied. Patients were treated palliatively by either MSI or DIT by the patient's or the next of kin's decision. Outcomes included technical and clinical success, complication rates, and survival. Of the 164 patients with malignant gastric and duodenal outlet obstructions, 80 (49%) underwent stent insertion as the primary therapy, while the remaining 84 (51%) received DIT. Clinical characteristics were similar between the two groups. In the MSI cohort initial stent implantation was successful in 73 patients (91%), two stents were used in 5 patients, and delayed additional stent insertion for stent obstruction related to tumor overgrowth was required in 3 patients during follow-up. In the DIT cohort the technical success rate was 94%, 3 patients required two stents, and stent obstruction occurred in 2 patients after initial stent placement. Early postprocedural clinical success, indicated by average dysphagia score, improved significantly in both groups: MSI group, from 4.56 to 1.51 (P < 0.01); and DIT group, from 4.38 to 1.48 (p < 0.01). There were no short-term complications. Late complications including hematemesis (n = 3), migration (n = 12), and stent occlusion due to tumor overgrowth (n = 5) were evenly distributed between the groups. In the DIT group chemotherapy-induced neutropenia and transient renal dysfunction were detected in six patients, which improved after symptomatic management. Mean survival time after the procedure was 5.9 and 11.1 months for MSI and DIT, respectively (P < 0.001). In conclusion, both MSI and DIT offer effective palliation for malignant gastroduodenal obstruction, but DIT appears to offer superior survival over MSI alone. Ideally, a prospective randomized trial comparing these two techniques should be carried out to validate this result.« less

Stent design favorably influences the vascular response in normal porcine coronary arteries.

PubMed

Carter, A J; Scott, D; Rahdert, D; Bailey, L; De Vries J; Ayerdi, K; Turnlund, T; Jones, R; Virmani, R; Fischell, T A

1999-03-01

The purpose of this study was to compare the arterial response following implantation of a stainless-steel, balloon-expandable, tubular slotted stent with that of a novel computer-designed, multi-cellular stent in normal porcine coronary arteries. Intracoronary stent placement has evolved into the primary strategy for percutaneous revascularization of symptomatic coronary arterial lesions. Presently there is intense interest in developing new stent designs to improve stent delivery and biocompatability. Computer-assisted design was utilized to develop a balloon-expandable stent with symmetric expansion properties, uniform arterial wall coverage, longitudinal flexibility and radial strength. Quantitative coronary angiography and histological assessment of the stented arteries was used to evaluate the acute and chronic vascular responses to a stainless-steel, balloon-expandable, tubular slotted stent as compared to the computer-designed BX stent in the normolipemic swine. Forty stents (24 BX, 16 tubular slotted) were implanted in 19 miniature swine at a mean inflation pressure of 9 atm using identical delivery systems. Eight of the BX and none of the tubular slotted stents were post-dilated with a non-compliant balloon at 12-14 atm. The mean stent-to-artery ratio was similar for the BX (1.03 +/- 0.06) and tubular slotted (1.04 +/- 0.11; p = 0.59) designs. Protrusion or asymmetric radial flaring of a strut at the stent margin was present in 1 of 23 BX stents (4.3%) and 10 of 15 tubular slotted stents (66.7%; p < 0.0001). The mean arterial injury score was significantly less for the BX stent (0.2 +/- 0.2) as compared with the tubular slotted stents (0.4 +/- 0.4; p = 0.025). At 3 days, thrombus area was similar for the BX and tubular slotted designs (0.42 +/- 0.16 mm2 versus 0.44 +/- 0.18 mm2, respectively; p = 0.88). The mean neointimal area was significantly less for the BX at 2 months (1.09 +/- 0.25 mm2 versus 2.93 +/- 2.26 mm2 in the tubular slotted stent) and at 6 months (1.10 +/- 0.26 mm2 versus 2.07 +/- 0.65 mm2 in the tubular slotted stent; p = 0.01), resulting in approximately 50% less in-stent stenosis. The arterial response to a balloon-expandable stent can be favorably influenced by computer-assisted modification of design in an experimental model. Further study is warranted to determine the impact of stent design upon clinical in-stent restenosis.

Biomimicry, vascular restenosis and coronary stents.

PubMed

Schwartz, R S; van der Giessen, W J; Holmes, D R

1998-01-01

Biomimicry is in its earliest stages and is being considered in the realm of tissue engineering. If arterial implants are to limit neointimal thickening, purely passive structures cannot succeed. Bioactivity must be present, either by pharmacologic intervention or by fabricating a 'living stent' that contains active cellular material. As tissue engineering evolves, useful solutions will emerge from applying this knowledge directly to vascular biologic problems resulting from angioplasty, stenting, and vascular prosthesis research.

Reliable porcine coronary model of chronic total occlusion using copper wire stents and bioabsorbable levo-polylactic acid polymer.

PubMed

Sim, Doo Sun; Jeong, Myung Ho; Cha, Kyoung Rae; Park, Suk Ho; Park, Jong Oh; Shin, Young Min; Shin, Heungsoo; Hong, Young Joon; Ahn, Youngkeun; Schwartz, Robert S; Kang, Jung Chaee

2012-12-01

Chronic total occlusion (CTO) remains a challenge in interventional cardiology. We investigated the feasibility and reliability of copper wire stents and levo-polylactic acid (l-PLA) as a means of CTO induction in a porcine model. In one group of 20 swine, copper stents were crimped on a 3.0mm angioplasty balloon and inserted into the mid-left anterior descending coronary artery (LAD). In the other group of 20 swine, l-PLA was wrapped on a guidewire and pushed into the distal LAD with a 3.0mm balloon catheter to induce embolization. Of 20 swine which underwent copper stent implantation, 13 died of stent thrombosis. In the remaining 7 swine, total or near total occlusion with collateral circulation was observed at 5 weeks. Of 20 swine which underwent l-PLA embolization, 4 died of ventricular fibrillation during or shortly after the procedure. Serial histopathologic studies showed complete absorption of the polymer with replacement by fibrotic tissue approximately 4 weeks following the polymer implantation. CTO could be reliably induced in porcine coronary arteries by copper stents and l-PLA. These models may support investigation of new percutaneous devices to facilitate CTO interventions. Copyright © 2012 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.

Fracture and Collapse of Balloon-Expandable Stents in the Bilateral Common Iliac Arteries Due to Shiatsu Massage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ichihashi, Shigeo, E-mail: shigeoichihashi@yahoo.co.jp; Higashiura, Wataru; Itoh, Hirofumi

2012-12-15

We report a case of stent fracture and collapse of balloon-expandable stents caused by shiatsu massage. A 76-year-old man presented with complaints of intermittent claudication of the right lower extremity. Stenoses of the bilateral common iliac arteries (CIAs) were detected. Balloon-expandable stents were deployed in both CIAs, resulting in resolution of symptoms. Five months later, pelvis x-ray showed collapse of both stents. Despite the stent collapse, the patient was asymptomatic, and his ankle brachial index values were within the normal range. Further history showed that the patient underwent daily shiatsu therapy in the umbilical region, which may have triggered collapsemore » of the stent. Physicians should advise patients to avoid compression of the abdominal wall after implantation of a stent in the iliac artery.« less

Comparison of expandable endotracheal stents in the treatment of surgically induced piglet tracheomalacia.

PubMed

Mair, E A; Parsons, D S; Lally, K P; Van Dellen, A F

1991-09-01

Present surgical alternatives for pediatric tracheobronchomalacia are limited and associated with many potentially undesirable complications. The feasibility of different intraluminal expandable endotracheal stents for the treatment of surgically induced tracheomalacia was analyzed in 27 piglets. A potentially fatal tracheomalacia was surgically created. Either a stainless steel "zig-zag" stent or a woven polymeric stent was then implanted. Tracheal patency, mucosal function, histopathologic respiratory tract changes, and effects of the stent on esophageal motility were evaluated over a 16-week period. Piglets with steel stents uniformly experienced intense inflammation leading to tracheal dysfunction and death. Piglets with polymeric stents experienced minimal respiratory symptoms. Expandable polymeric endotracheal stents alleviate surgically induced piglet tracheomalacia, were easy to insert, allowed for tracheal growth, and reduced the need for high-risk surgical procedures with prolonged ventilatory support.

Ex vivo blood vessel bioreactor for analysis of the biodegradation of magnesium stent models with and without vessel wall integration.

PubMed

Wang, Juan; Liu, Lumei; Wu, Yifan; Maitz, Manfred F; Wang, Zhihong; Koo, Youngmi; Zhao, Ansha; Sankar, Jagannathan; Kong, Deling; Huang, Nan; Yun, Yeoheung

2017-03-01

Current in vitro models fail in predicting the degradation rate and mode of magnesium (Mg) stents in vivo. To overcome this, the microenvironment of the stent is simulated here in an ex vivo bioreactor with porcine aorta and circulating medium, and compared with standard static in vitro immersion and with in vivo rat aorta models. In ex vivo and in vivo conditions, pure Mg wires were exposed to the aortic lumen and inserted into the aortic wall to mimic early- and long-term implantation, respectively. Results showed that: 1) Degradation rates of Mg were similar for all the fluid diffusion conditions (in vitro static, aortic wall ex vivo and in vivo); however, Mg degradation under flow condition (i.e. in the lumen) in vivo was slower than ex vivo; 2) The corrosion mode in the samples can be mainly described as localized (in vitro), mixed localized and uniform (ex vivo), and uniform (in vivo); 3) Abundant degradation products (MgO/Mg(OH) 2 and Ca/P) with gas bubbles accumulated around the localized degradation regions ex vivo, but a uniform and thin degradation product layer was found in vivo. It is concluded that the ex vivo vascular bioreactor provides an improved test setting for magnesium degradation between static immersion and animal experiments and highlights its promising role in bridging degradation behavior and biological response for vascular stent research. Magnesium and its alloys are candidates for a new generation of biodegradable stent materials. However, the in vitro degradation of magnesium stents does not match the clinical degradation rates, corrupting the validity of conventional degradation tests. Here we report an ex vivo vascular bioreactor, which allows simulation of the microenvironment with and without blood vessel integration to study the biodegradation of magnesium implants in comparison with standard in vitro test conditions and with in vivo implantations. The bioreactor did simulate the corrosion of an intramural implant very well, but showed too high degradation for non-covered implants. It is concluded that this system is in between static incubation and animal experiments concerning the predictivity of the degradation. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Evaluation of Bleb Morphology and Reduction in IOP and Glaucoma Medication following Implantation of a Novel Gel Stent

PubMed Central

Spinetta, Roberta; Cannizzo, Paola Maria Loredana; Consolandi, Giulia; Lavia, Carlo; Germinetti, Francesco; Rolle, Teresa

2017-01-01

Objective To evaluate the efficacy and safety of the Xen Gel Stent and provide a macro- and microscopic analyses of bleb morphology. Methods A prospective 12-month study on patients with primary open-angle glaucoma. Patients underwent implantation of the XEN Gel Stent (Allergan INC, Dublin, Ireland) either alone or combined with a cataract surgery. Biomicroscopy, in vivo confocal microscopy (IVCM), and anterior segment-optical coherence tomography (AS-OCT) were used to assess bleb morphology. Safety parameters were adverse events, best corrected visual acuity, visual field, and corneal endothelial cell loss. A postoperative IOP ≤ 18 mmHg without or on medications was respectively defined as complete and qualified success while an IOP ≥ 18 mmHg was defined as failure. Results Twelve eyes of 11 patients were evaluated. At one year, 5 out of 10 patients available achieved a complete success while five were qualified success. AS-OCT showed that bleb wall reflectivity was significantly higher in the failure group; IVCM revealed that stromal density was significantly lower in the success group. No safety issues were recorded. Conclusion Implantation of the XEN Gel Stent appears to be a safe and effective procedure. AS-OCT and IVCM may be helpful in bleb assessment. PMID:28751986

Paclitaxel Drug-eluting Tracheal Stent Could Reduce Granulation Tissue Formation in a Canine Model

PubMed Central

Wang, Ting; Zhang, Jie; Wang, Juan; Pei, Ying-Hua; Qiu, Xiao-Jian; Wang, Yu-Ling

2016-01-01

Background: Currently available silicone and metallic stents for tracheal stenosis are associated with many problems. Granulation proliferation is one of the main complications. The present study aimed to evaluate the efficacy of paclitaxel drug-eluting tracheal stent in reducing granulation tissue formation in a canine model, as well as the pharmacokinetic features and safety profiles of the coated drug. Methods: Eight beagles were randomly divided into a control group (bare-metal stent group, n = 4) and an experimental group (paclitaxel-eluting stent group, n = 4). The observation period was 5 months. One beagle in both groups was sacrificed at the end of the 1st and 3rd months, respectively. The last two beagles in both groups were sacrificed at the end of 5th month. The proliferation of granulation tissue and changes in tracheal mucosa were compared between the two groups. Blood routine and liver and kidney function were monitored to evaluate the safety of the paclitaxel-eluting stent. The elution method and high-performance liquid chromatography were used to characterize the rate of in vivo release of paclitaxel from the stent. Results: Compared with the control group, the proliferation of granulation tissue in the experimental group was significantly reduced. The drug release of paclitaxel-eluting stent was the fastest in the 1st month after implantation (up to 70.9%). Then, the release slowed down gradually. By the 5th month, the release reached up to 98.5%. During the observation period, a high concentration of the drug in the trachea (in the stented and adjacent unstented areas) and lung tissue was not noted, and the blood test showed no side effect. Conclusions: The paclitaxel-eluting stent could safely reduce the granulation tissue formation after stent implantation in vivo, suggesting that the paclitaxel-eluting tracheal stent might be considered for potential use in humans in the future. PMID:27824004

Predictors and Long-Term Clinical Impact of Acute Stent Malapposition: An Assessment of Dual Antiplatelet Therapy With Drug-Eluting Stents (ADAPT-DES) Intravascular Ultrasound Substudy.

PubMed

Wang, Bin; Mintz, Gary S; Witzenbichler, Bernhard; Souza, Cristiano F; Metzger, D Christopher; Rinaldi, Michael J; Duffy, Peter L; Weisz, Giora; Stuckey, Thomas D; Brodie, Bruce R; Matsumura, Mitsuaki; Yamamoto, Myong-Hwa; Parvataneni, Rupa; Kirtane, Ajay J; Stone, Gregg W; Maehara, Akiko

2016-12-22

The impact of acute stent malapposition (ASM) on long-term clinical outcomes in patients undergoing percutaneous coronary intervention is still controversial. We sought to evaluate predictors and long-term clinical outcomes of ASM. ADAPT-DES (Assessment of Dual Antiplatelet Therapy With Drug-Eluting Stents) was a prospective multicenter study of 8663 patients undergoing percutaneous coronary intervention using drug-eluting stents. In a prespecified intravascular ultrasound-guided substudy, 2072 patients with 2446 culprit lesions had post-percutaneous coronary intervention intravascular ultrasound and were classified according to the presence or absence of ASM. After intravascular ultrasound-guided percutaneous coronary intervention, the overall prevalence of ASM after successful drug-eluting stents implantation was 14.4% per patient and 12.6% per lesion. Compared to lesions without ASM, lesions with ASM had larger in-stent lumen areas, larger stent areas, and larger in-stent vessel areas. A larger mean plaque area along with more attenuated plaque was observed in lesions with ASM versus lesions without ASM. Lesions with ASM had greater proximal and distal reference lumen areas and more distal, but not proximal, reference calcium compared to lesions without ASM. At 2-year follow-up, there was no significant difference in the incidence of cardiac death; myocardial infarction; early, late, or very late stent thrombosis; or clinically driven target lesion revascularization in patients with ASM versus those without ASM. Furthermore, ASM was not an independent predictor of 2-year major adverse cardiac events or target lesion revascularization even when forced into the multivariate model. In patients treated with intravascular ultrasound-guided drug-eluting stents implantation, ASM was not associated with adverse clinical events during long-term follow-up including, but not limited to, stent thrombosis. URL: https://www.clinicaltrials.gov. Unique identifier: NCT00638794. © 2016 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

Mechanical Properties of High Entropy Alloy Al0.1CoCrFeNi for Peripheral Vascular Stent Application.

PubMed

Alagarsamy, Karthik; Fortier, Aleksandra; Komarasamy, Mageshwari; Kumar, Nilesh; Mohammad, Atif; Banerjee, Subhash; Han, Hai-Chao; Mishra, Rajiv S

2016-12-01

High entropy alloys (HEAs) are new class of metallic materials with five or more principal alloying elements. Due to this distinct concept of alloying, the HEAs exhibit unique properties compared to conventional alloys. The outstanding properties of HEAs include increased strength, superior wear resistance, high temperature stability, increased fatigue properties, good corrosion, and oxidation resistance. Such characteristics of HEAs have generated significant interest among the scientific community. However, their applications are yet to be explored. This paper discusses the mechanical behavior and microstructure of Al 0.1 CoCrFeNi HEA subjected to thermo-mechanical processing, and its potential application in peripheral vascular stent implants that are prone to high failure rates. Results show that Al 0.1 CoCrFeNi alloy possesses characteristics that compare well against currently used stent materials and it can potentially find use in peripheral vascular stent implants and extend their life-cycle.

[Self-expandable metallic biliary endoprosthesis in malignant obstructive jaundice].

PubMed

Güitrón-Cantú, Alfredo; Adalid-Martínez, Raúl; Gutiérrez-Bermúdez, José A

2005-01-01

Implantation of metallic stents for malignant biliary strictures has been recognized to be effective alternatives. To show our experience in metallic stents for palliation of malignant biliary strictures. Seventy three patients (38 males, 35 females, mean age 64.26) with malignant biliary strictures have been treated by implantation of metallic stents. Causes of obstruction were pancreatic carcinoma (23/73, 31.5%), bile duct carcinoma (31/73, 42.5%), carcinoma of ampula of Vater (11/73, 15%) and Klatskin tumor (3/73, 4.1%). Endoscopic procedure was successful in all cases. Neither procedure-related morbidity nor mortality was observed. Life surviving curve was 9 months and showed significant difference (p < 0.0071) in patients with carcinoma of ampula of Vater. Self-expanding metal endoprosthesis is a recognized method of palliation in malignant biliary obstruction. It efficiently relieves jaundice and generally improves comfort and nutritional status during the patient's remaining lifetime. The metallic stents are advantageous in patients surviving 6 months or less.

[Migration of a stent implanted in the pulmonary artery of a patient with tetralogy of Fallot].

PubMed

Palomero Rodríguez, M A; Gabaldón Rivilla, M; Cabestrero Alonso, D; Gonzalez Cibrián, C; Abelleira Pardeiro, C; Centella Hernánez, T; Collado Gutierrez, R; Asuero de Lis, M S; Gómez González, R

2014-05-01

Tetralogy of Fallot is a congenital heart disease that accounts for 11-13% of the congenital cardiomyopathies. Stenosis and hyperplasia of the pulmonary arteries occur in a high proportion of them as this disease causes a native stenosis of the pulmonary branch, which can be surgically repaired with a stent. The use of balloon expandable intravascular stents is an alternative technique to further surgery in patients with congenital heart diseases. However, despite the gradual increase in their use, the limited number of procedures, combined with the wide anatomical variability and different characteristics of these patients, even in expert hands, stent implants are associated with a not inconsiderable incidence of complications. These are not always obvious and often require performing surgery in patients who have already had multiple interventions, thus increasing the complexity and the risk. Copyright © 2013 Sociedad Española de Anestesiología, Reanimación y Terapéutica del Dolor. Published by Elsevier España. All rights reserved.

Testing prospectively the effectiveness and safety of paclitaxel-eluting stents in over 1000 very high-risk patients: design, baseline characteristics, procedural data and in-hospital outcomes of the multicenter Taxus in Real-life Usage Evaluation (TRUE) Study.

PubMed

Biondi-Zoccai, Giuseppe G L; Sangiorgi, Giuseppe M; Antoniucci, David; Grube, Eberhard; Di Mario, Carlo; Reimers, Bernard; Tamburino, Corrado; Agostoni, Pierfrancesco; Cosgrave, John; Colombo, Antonio

2007-05-02

Paclitaxel-eluting stents (PES) have been proved effective in randomized trials enrolling highly selected patients. Yet, given the uncertainty concerning results of PES implantation in very high-risk patients and lesions, we designed a prospective multicenter registry, the Taxus in Real-life Usage Evaluation (TRUE) Study. STUDY DESIGN, PATIENT CHARACTERISTICS AND IN-HOSPITAL OUTCOMES: Consecutive patients undergoing PES implantation were enrolled provided that the target lesion treated with PES was an unprotected left main (ULM), a true bifurcation, a chronic total occlusion (CTO), a long lesion (>28 mm), located in a small vessel (<2.75 mm), or the patient had diabetes mellitus. Clinical events will be adjudicated at 1, 7 and 12 months, with 4- to 8-month angiographic follow-up. The primary end-point will be the 7-month occurrence of major adverse cardiovascular events (MACE, i.e. the composite of cardiac death, non-fatal myocardial infarction [MI], coronary artery bypass grafting [CABG] and percutaneous target vessel revascularization [TVR]). To date, patient enrollment has been completed reaching the target of 1065 subjects. These included 322 (30.2%) diabetics, 115 (10.8%) subjects undergoing PES implantation for ULM, 229 (21.5%) in a bifurcation, 191 (17.9%) in a CTO, 430 (40.4%) in a small vessel, and 289 (27.1%) in a long lesion. An average of 1.5+/-0.6 vessels and 2.0+/-1.0 lesions were treated per patient, with 2.0+/-1.2 PES implanted per patient, and a 46+/-30 mm total PES length per patient. In-hospital MACE occurred in 39 (3.7%) patients, with 2 (0.2%) cardiac deaths, 32 (3.0%) MI, 5 (0.5%) TVR, no CABG, and 4 (0.4%) acute stent thromboses. Despite the availability of randomized trials, only carefully designed and prospective registries can provide timely and accurate assessment of the risk-benefit profile of PES in very high-risk patients. Indeed, the TRUE Study, including as much as 115 ULM and 229 bifurcation interventions, should give important insights into the outcome of PES in such an unprecedented and challenging context.

Endovascular treatment of popliteal artery segments P1 and P2 in patients with critical limb ischemia: initial experience using a helical nitinol stent with increased radial force.

PubMed

Goltz, Jan P; Ritter, Christian O; Kellersmann, Richard; Klein, Detlef; Hahn, Dietbert; Kickuth, Ralph

2012-06-01

To evaluate efficacy, safety, and midterm patency of a helical, self-expanding nitinol stent after failed percutaneous transluminal angioplasty (PTA) of popliteal artery segments P1 and P2 in patients with chronic critical limb ischemia (CLI) or lifestyle-limiting claudication. Between February 2009 and March 2011, 40 patients (23 men; mean age 77±10 years) classified as Rutherford category 3 (n = 10) or 4/5 (n = 30) underwent PTA of the proximal and mid popliteal artery followed by implantation of a SUPERA stent for elastic recoil, residual stenosis, or flow-limiting dissection. All patients had an elevated operative risk. Before and after the procedure and during the 12-month follow-up, a clinical investigation, ankle-brachial-index (ABI) measurement, and color-coded duplex sonography and/or digital subtraction angiography were performed. Primary endpoints were limb salvage and anatomical patency at 12 months. Stent implantation was successful in all patients. The major complication rate was 7.5% (an access-site pseudoaneurysm, 2 retroperitoneal hematomas, and 1 death from retroperitoneal bleeding). Mean follow-up was 15.9 months (range 0.5-27.9). The mean baseline ABI of 0.37 significantly increased to 0.91 at 12 months (p<0.01). Three (7.5%) patients underwent bypass surgery owing to lack of clinical improvement (<0.10 improvement in ABI). Primary and secondary patency rates at 12 months in the 34 patients eligible for follow-up were 68.4% and 79.8%, respectively. The major amputation rate was 5% at 1 year. Five (12.5%) in-stent stenoses and 1 of 2 (5.0%) in-stent occlusions were successfully recanalized (the second occlusion was asymptomatic). Implantation of this helical stent into segments of the popliteal artery at the knee joint in CLI patients is a safe and clinically effective bailout method with acceptable intermediate patency.

Comparative Case-Control analysis of a dedicated self-expanding Biolimus A9-eluting Bifurcation stent versus provisional or mandatory side branch intervention strategies in the treatment of coronary bifurcation lesions.

PubMed

Ohlow, Marc-Alexander; Farah, Ahmed; Richter, Stefan; El-Garhy, Mohamad; von Korn, Hubertus; Lauer, Bernward

2017-07-01

In a number of coronary bifurcation lesions, both the main vessel and the side branch (SB) need stent coverage. To analyze the procedural performance and the impact on radiation times (RT) and contrast medium consumption (CMC) of the Axxess™ stent system (Biosensors, Switzerland) treating de novo bifurcation lesions (DBL). One hundred and ten consecutive prospectively enrolled cases (Axxess Group) and 110 age, sex, and lesion location matched controls undergoing mandatory (Group A, n = 56) or provisional (Group B, n = 54) SB intervention were analyzed. Although more pre-dilatation was performed in the Axxess Group (92.7% vs. 46.4% [Group A] vs. 24.1% [Group B]), and more stents were used (2.4 vs. 1.2 vs. 1.05), RT and CMC were significantly lower in the Axxess Group [7.9 min/129 ml vs. 14.2 min/209 ml vs. 7.8 min/152 ml; P < 0.001]. Final Thrombolysis In Myocardial Infarction three flow in both branches was significantly more frequent in the Axxess Group (98.2% vs. 94.6% vs. 88.9%; P = 0.02), and post-interventional troponin T elevations were the lowest in the Axxess Group. Eighty one percent of the Axxess-stents could be implanted without technical difficulties. Difficult implantations procedures were mainly related to coronary anatomy. There was no safety concerns (cardiac death, stent-thrombosis) compared to controls. Cumulative 6-months MACE rates were 11% versus 23% versus 25%. TLR rates at 6-months were 5%, 18%, and 15%, respectively. Axxess bifurcation stent system procedures were associated with significantly less RT and CMC compared to conventional DBL therapy strategies. Difficult coronary anatomy may hinder successful implantation and a learning curve has to be considered. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

[Acetylsalicylic acid desensitization in the new era of percutaneous coronary intervention].

PubMed

Fuertes Ferre, Georgina; Ferrer Gracia, Maria Cruz; Calvo Cebollero, Isabel

2015-09-21

Dual antiplatelet therapy is essential in patients undergoing percutaneous coronary intervention with stent implantation. Hypersensitivity to acetylsalicylic acid (ASA) limits treatment options. Desensitization to ASA has classically been studied in patients with respiratory tract disease. Over the last years, many protocols have been described about ASA desensitization in patients with ischemic heart disease, including acute coronary syndrome and the need for coronary stent implantation. It is important to know the efficacy and safety of ASA desensitization in these patients. Copyright © 2014 Elsevier España, S.L.U. All rights reserved.

Percutaneous laser-assisted recanalization of long chronic iliac artery occlusions: primary and mid-term results.

PubMed

Balzer, Jörn O; Gastinger, Verena; Thalhammer, Axel; Ritter, Ralf G; Lindhoff-Last, Edelgard; Schmitz-Rixen, Thomas; Vogl, Thomas J

2006-02-01

We report the primary and mid-term outcome of patients with long chronic iliac artery occlusions after percutaneous excimer-laser-assisted interventional recanalization. Between 2000 and 2001, 43 patients with 46 chronic occlusions of either the common iliac artery (n=27), the external iliac artery ( n=13) or both (n=3) underwent laser-assisted percutaneous transluminal angioplasty and implantation of stents. The average length of the occlusion was 57.1+/-26 mm. After laser-assisted angioplasty and implantation of a total of 60 stents, the patients were followed up for up to 4 years. Patency rates were analyzed by ankle-brachial index (ABI) measurement and duplex ultrasound. The primary technical success rate was 95.3%, with a major complication rate of 6.9%. Clinical improvement as categorized by the Rutherford guidelines could be observed in 97.6% of cases. The ABI of all patients improved from an average of 0.46+/-0.08 before intervention to 0.97+/-0.13 at the end of the follow-up period. The overall primary patency rate was 86.1%. Four reinterventions were successful (secondary patency rate 95.4%). The mid-term results of the percutaneous recanalization of iliac artery occlusions with primary and secondary patency rates of 86.1 and 95.4% are similar to those of the treatment of short stenoses.

76 FR 56200 - Circulatory System Devices Panel of the Medical Devices Advisory Committee; Notice of Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2011-09-12

... Stent. The ZILVER-PTX Stent is a self-expanding nitinol stent coated on its outer surface with the... millimeter. The ZILVER-PTX Stent is available in diameters ranging from 5 to 10 millimeters (mm) and lengths... deployment, the ZILVER-PTX Stent expands to establish and maintain patency in the stented region. The...

The numerical simulation study of hemodynamics of the new dense-mesh stent

NASA Astrophysics Data System (ADS)

Ma, Jiali; Yuan, Zhishan; Yu, Xuebao; Feng, Zhaowei; Miao, Weidong; Xu, Xueli; Li, Juntao

2017-09-01

The treatment of aortic aneurysm in new dense mesh stent is based on the principle of hemodynamic changes. But the mechanism is not yet very clear. This paper analyzed and calculated the hemodynamic situation before and after the new dense mesh stent implanting by the method of numerical simulation. The results show the dense mesh stent changed and impacted the blood flow in the aortic aneurysm. The changes include significant decrement of blood velocity, pressure and shear forces, while ensuring blood can supply branches, which means the new dense mesh stent's hemodynamic mechanism in the treatment of aortic aneurysm is clearer. It has very important significance in developing new dense mesh stent in order to cure aortic aneurysm.

Significantly lower incidence of early definite stent thrombosis of drug-eluting stents after unrestricted use in Japan using ticlopidine compared to western countries using clopidogrel: a retrospective comparison with western mega-studies.

PubMed

Ishikawa, Tetsuya; Nakano, Yosuke; Endoh, Akira; Kubota, Takeyuki; Suzuki, Teruhiko; Nakata, Koutarou; Miyamoto, Takashi; Murakami, Michiaki; Sakamoto, Hiroshi; Imai, Kamon; Mochizuki, Seibu; Yoshimura, Michihiro; Mutoh, Makoto

2009-10-01

The incidence of definite stent thrombosis (ST) after use of drug-eluting stents (DES), as defined by the Academic Research Consortium, is known to be lower in Japan than in western countries. However, a statistical difference in the incidence of early definite ST (EDST) associated with the unrestricted use of DES has not yet been documented. Therefore, the incidence of EDST in our Japanese institute after unrestricted use of DES was retrospectively compared with those reported in western mega-studies. During the 40 months from August 2004 to November 2007 (before approval of clopidogrel in Japan), DES were implanted in 3605 lesions in 1885 patients in our institute; lesion- and patient-associated percentages of DES use were 95.2% and 94.7%, respectively. Mean stent length per lesion was 33.2 mm, emergent procedures and ST-elevation myocardial infarctions made up 33.7% and 16.4% of the procedures, respectively, intravascular ultrasonography was used 96.0% of the time, a distal protection device for acute coronary syndrome was used 68.7% of the time, and the mean maximum inflation pressure was 19.5 atm. EDST was observed in five lesions (0.139%) in four patients (0.212%). The incidence of patient-associated EDST at our center was significantly lower than in four western mega-studies (0.736%, 66 of 8970 patients; 0.634%, 149 of 23,500; 0.595%, 52 of 8402; 0.997%, 20 of 2006) (p<0.05, <0.01, <0.05, <0.01, respectively, using a chi(2)-test). Due to differences in procedural approaches in Japan, the incidence of EDST after unrestricted use of DES was significantly lower than in western countries.

Relation between calcium burden, echocardiographic stent frame eccentricity and paravalvular leakage after corevalve transcatheter aortic valve implantation.

PubMed

Di Martino, Luigi F M; Soliman, Osama I I; van Gils, Lennart; Vletter, Wim B; Van Mieghem, Nicolas M; Ren, Ben; Galema, Tjebbe W; Schultz, Carl; de Jaegere, Peter P T; Di Biase, Matteo; Geleijnse, Marcel L

2017-06-01

Paravalvular aortic leakage (PVL) after transcatheter aortic valve implantation (TAVI) is a complication with potentially severe consequences. The relation between native aortic root calcium burden, stent frame eccentricity and PVL was not studied before. Two-hundred-and-twenty-three consecutive patients with severe aortic stenosis who underwent TAVI with a Medtronic CoreValve System© and who had available pre-discharge transthoracic echocardiography were studied. Echocardiographic stent inflow frame eccentricity was defined as major-minor diameter in a short-axis view >2 mm. PVL was scored according to the updated Valve Academic Research Consortium (VARC-2) recommendations. In a subgroup of 162 (73%) patients, the calcium Agatston score was available. Stent frame eccentricity was seen in 77 (35%) of patients. The correlation between the Agatston score and stent frame eccentricity was significant (ρ = 0.241, P = 0.003). Paravalvular leakage was absent in 91 cases (41%), mild in 67 (30%), moderate in 51 (23%), and severe in 14 (6%) cases. The correlation between stent frame eccentricity and PVL severity was significant (ρ = 0.525, P < 0.0001). There was a relation between particular eccentric stent frame shapes and the site of PVL. Calcification of the aortic annulus is associated with a subsequent eccentric shape of the CoreValve prosthesis. This eccentric shape results in more PVL, with the localization of PVL related to the shape of stent frame eccentricity. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2017. For permissions, please email: journals.permissions@oup.com.

Catheter-based tricuspid valve replacement: first experimental data of a newly designed bileaflet stent graft prosthesis.

PubMed

Lausberg, Henning F; Gryszkiewicz, Rafal; Kuetting, Maximilian; Baumgaertner, Moritz; Centola, Marcos; Wendel, Hans-Peter; Nowak-Machen, Martina; Schibilsky, David; Kruger, Tobias; Schlensak, Christian

2017-07-01

Moderate or severe degree tricuspid valve regurgitation (TVR) is associated with high rates of morbidity and mortality. Surgical correction as the only therapeutic option offers unsatisfactory results. Recently, several interventional procedures have been introduced clinically in a limited cohort. We present our initial experiments with an innovative interventional valved stent graft for treatment of TVR. A newly designed porcine pericardium-covered nitinol stent graft with a lateral bicuspid valve was adapted to size in a cadaver study. After haemodynamic testing in an ex vivo perfusion setup, vascular access, valve delivery and function were investigated in an ovine animal model ( n  = 7). The device was implanted successfully in all animals. Vascular access was established surgically via the femoral vein without any vascular complications. Angiography demonstrated the correct position of the device with proper sealing of both venae cavae in 6 animals. In 1 extremely large animal, the position of the device was considered too cranial but still acceptable. Correct valve function was verified in all animals by both angiography and echocardiography. There were no persistent arrhythmias other than during valve implant. All animals survived the implant procedure and were sacrificed electively. This study demonstrated that this new valved stent graft could be delivered safely with correct positioning and valve function in this ovine model. Further long-term studies in animals implanted with the device after creation of tricuspid regurgitation are necessary to prove the haemodynamic benefit of this procedure. © The Author 2017. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

Automatic three-dimensional registration of intra-vascular optical coherence tomography images for the clinical evaluation of stent implantation over time

NASA Astrophysics Data System (ADS)

Ughi, Giovanni J.; Adriaenssens, Tom; Larsson, Matilda; Dubois, Christophe; Sinnaeve, Peter; Coosemans, Mark; Desmet, Walter; D'hooghe, Jan

2012-01-01

In the last decade a large number of new intracoronary devices (i.e. drug-eluting stents, DES) have been developed to reduce the risks related to bare metal stent (BMS) implantation. The use of this new generation of DES has been shown to substantially reduce, compared with BMS, the occurrence of restenosis and recurrent ischemia that would necessitate a second revascularization procedure. Nevertheless, safety issues on the use of DES persist and full understanding of mechanisms of adverse clinical events is still a matter of concern and debate. Intravascular Optical Coherence Tomography (IV-OCT) is an imaging technique able to visualize the microstructure of blood vessels with an axial resolution <20 μm. Due to its very high spatial resolution, it enables detailed in-vivo assessment of implanted devices and vessel wall. Currently, the aim of several major clinical trials is to observe and quantify the vessel response to DES implantation over time. However, image analysis is currently performed manually and corresponding images, belonging to different IV-OCT acquisitions, can only be matched through a very labor intensive and subjective procedure. The aim of this study is to develop and validate a new methodology for the automatic registration of IV-OCT datasets on an image level. Hereto, we propose a landmark based rigid registration method exploiting the metallic stent framework as a feature. Such a tool would provide a better understanding of the behavior of different intracoronary devices in-vivo, giving unique insights about vessel pathophysiology and performance of new generation of intracoronary devices and different drugs.

Long-term surveillance of zinc implant in murine artery: Surprisingly steady biocorrosion rate.

PubMed

Drelich, Adam J; Zhao, Shan; Guillory, Roger J; Drelich, Jaroslaw W; Goldman, Jeremy

2017-08-01

Metallic zinc implanted into the abdominal aorta of rats out to 6months has been demonstrated to degrade while avoiding responses commonly associated with the restenosis of vascular implants. However, major questions remain regarding whether a zinc implant would ultimately passivate through the production of stable corrosion products or via a cell mediated fibrous encapsulation process that prevents the diffusion of critical reactants and products at the metal surface. Here, we have conducted clinically relevant long term in vivo studies in order to characterize late stage zinc implant biocorrosion behavior and products to address these critical questions. We found that zinc wires implanted in the murine artery exhibit steady corrosion without local toxicity for up to at least 20months post-implantation, despite a steady buildup of passivating corrosion products and intense fibrous encapsulation of the wire. Although fibrous encapsulation was not able to prevent continued implant corrosion, it may be related to the reduced chronic inflammation observed between 10 and 20months post-implantation. X-ray elemental and infrared spectroscopy analyses confirmed zinc oxide, zinc carbonate, and zinc phosphate as the main components of corrosion products surrounding the Zn implant. These products coincide with stable phases concluded from Pourbaix diagrams of a physiological solution and in vitro electrochemical impedance tests. The results support earlier predictions that zinc stents could become successfully bio-integrated into the arterial environment and safely degrade within a time frame of approximately 1-2years. Previous studies have shown zinc to be a promising candidate material for bioresorbable endovascular stenting applications. An outstanding question, however, is whether a zinc implant would ultimately passivate through the production of stable corrosion products or via a cell mediated tissue encapsulation process that prevented the diffusion of critical reactants and products at the metal surface. We found that zinc wires implanted in the murine artery exhibit steady corrosion for up to at least 20months post-implantation. The results confirm earlier predictions that zinc stents could safely degrade within a time frame of approximately 1-2years. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Biocompatibility and biodegradability of Mg-Sr alloys: the formation of Sr-substituted hydroxyapatite.

PubMed

Bornapour, M; Muja, N; Shum-Tim, D; Cerruti, M; Pekguleryuz, M

2013-02-01

Magnesium is an attractive material for use in biodegradable implants due to its low density, non-toxicity and mechanical properties similar to those of human tissue such as bone. Its biocompatibility makes it amenable for use in a wide range of applications from bone to cardiovascular implants. Here we investigated the corrosion rate in simulated body fluid (SBF) of a series of Mg-Sr alloys, with Sr in the range of 0.3-2.5%, and found that the Mg-0.5 Sr alloy showed the slowest corrosion rate. The degradation rate from this alloy indicated that the daily Sr intake from a typical stent would be 0.01-0.02 mg day⁻¹, which is well below the maximum daily Sr intake levels of 4 mg day⁻¹. Indirect cytotoxicity assays using human umbilical vascular endothelial cells indicated that Mg-0.5 Sr extraction medium did not cause any toxicity or detrimental effect on the viability of the cells. Finally, a tubular Mg-0.5 Sr stent sample, along with a WE43 control stent, was implanted into the right and left dog femoral artery. No thrombosis effect was observed in the Mg-0.5 Sr stent after 3 weeks of implantation while the WE43 stent thrombosed. X-ray diffraction demonstrated the formation of hydroxyapatite and Mg(OH)₂ as a result of the degradation of Mg-0.5 Sr alloy after 3 days in SBF. X-ray photoelectron spectroscopy further showed the possibility of the formation of a hydroxyapatite Sr-substituted layer that presents as a thin layer at the interface between the Mg-0.5 Sr alloy and the corrosion products. We believe that this interfacial layer stabilizes the surface of the Mg-0.5 Sr alloy, and slows down its degradation rate over time. Copyright © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

[Percutaneously implantable aortic valve: the JenaValve concept evolution].

PubMed

Figulla, Hans R; Ferrari, Markus

2006-10-01

Due to the increasing incidence of severe aortic stenosis in old and multimorbid patients, the percutaneous implantation of aortic valve-carrying stents has become an alternative to the surgical replacement of aortic valves. Starting in 1995, the authors developed a self-expanding stent which transferred the necessary forces for anchoring up to the aorta ascendens-a conception taken over from CoreValve. The further improvement of this idea over the past 11 years has led to a self-expanding, relatively short stent-valve system that is reliably positioned in the cusps of the old aortic valve and holds the old valve like a paper clip, thus transferring the holding forces physiologically. As compared to conventional systems, the sophisticated insertion catheter requires further chronic animal tests so as to represent a true alternative to the conventional surgical procedure.

Effect on Intimal Hyperplasia of Dexamethasone Released from Coated Metal Stents Compared with Non-Coated Stents in Canine Femoral Arteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Strecker, Ernst-Peter; Gabelmann, Andreas; Boos, Irene

1998-11-15

Purpose: Polymer-coated, dexamethasone (DXM)-releasing stents were tested in order to assess the efficacy of DXM released locally for the prevention of stent restenosis due to intimal hyperplasia. Methods: Strecker stents coated with a biodegradable membrane containing DXM were implanted percutaneously into the femoral artery in 14 dogs. The contralateral artery received a conventional non-coated stent serving as control. The drugs are eluted by degradation of the carrier membrane. Follow-up intraarterial digital subtraction angiography (DSA) was obtained at 3, 6, 9, 12, and 24 weeks with subsequent autopsy. Specimens for gross and microscopic pathology were obtained and histomorphometry was performed. Results:more » Four of 14 DXM-coated stents showed thrombotic occlusion within the first 3 weeks; ten DXM-coated stents remained patent. At follow-up DSA, DXM-coated stents showed a significantly wider lumen than the non-coated stents. At morphometry there was less intimal hyperplasia over DXM-coated stents than over non-coated stents (p < 0.05). Conclusion: DXM-coated stents reduce neointimal hyperplasia in dogs when compared with non-coated stents.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miyayama, Shiro, E-mail: s-miyayama@fukui.saiseikai.or.jp; Yamashiro, Masashi; Takeda, Taro

We report the successful management of acute cholecystitis using cystic duct stent placement in 3 patients with inoperable malignant cystic duct obstruction (2 cholangiocarcinoma and 1 pancreatic carcinoma). All patients underwent stent placement in the bile duct, using an uncovered stent in 2 and a covered stent in 1, to relieve jaundice occurring 8-184 days (mean 120 days) before the development of acute cholecystitis. The occluded cystic duct was traversed by a microcatheter and a stent was implanted 4-17 days (mean 12 days) after cholecystostomy. Acute cholecystitis was improved after the procedure in all patients. Two patients died 3 andmore » 10 months later, while 1 has survived without cholecystitis for 22 months after the procedure to date.« less

[Finite Element Analysis of Intravascular Stent Based on ANSYS Software].

PubMed

Shi, Gengqiang; Song, Xiaobing

2015-10-01

This paper adopted UG8.0 to bulid the stent and blood vessel models. The models were then imported into the finite element analysis software ANSYS. The simulation results of ANSYS software showed that after endothelial stent implantation, the velocity of the blood was slow and the fluctuation of velocity was small, which meant the flow was relatively stable. When blood flowed through the endothelial stent, the pressure gradually became smaller, and the range of the pressure was not wide. The endothelial shear stress basically unchanged. In general, it can be concluded that the endothelial stents have little impact on the flow of blood and can fully realize its function.

Use of a wire extender during neuroprotected vertebral artery angioplasty and stenting.

PubMed

Lesley, Walter S; Kumar, Ravi; Rangaswamy, Rajesh

2010-09-01

The off-label use of an extender wire during vertebral artery stenting and angioplasty with or with neuroprotection has not been previously reported. Retrospective, single-patient, technical report. After monorail balloon angioplasty was performed on a proximal left vertebral artery stenosis, the 190 cm long Accunet neuroprotection filter device was not long enough for delivery of an over-the-wire stent. After mating a 145 cm long, 0.014 inch extension wire to the filter device, a balloon-mounted Liberté stent was implanted with good angiographic and clinical results. The off-label use of an extender wire permits successful over-the-wire stenting on a monorail neuroprotection device for vertebral artery endosurgery.

Endoscopic Removal of a Nitinol Mesh Stent from the Ureteropelvic Junction after 15 Years

PubMed Central

Smrkolj, Tomaž; Šalinović, Domagoj

2015-01-01

We report a rare case of a patient with a large stone encrusted on a nitinol mesh stent in the ureteropelvic junction. The stent was inserted in the year 2000 after failure of two pyeloplasty procedures performed due to symptomatic ureteropelvic junction stenosis. By combining minimally invasive urinary stone therapies—extracorporeal shock wave lithotripsy, semirigid ureterorenoscopy with laser lithotripsy, and percutaneous nephrolithotomy—it was possible to completely remove the encrusted stone and nitinol mesh stent that was implanted for 15 years, rendering the patient symptom and obstruction free. PMID:26697258

Interaction of intraluminal tissue and coronary sinus lead stabilized with stent placement.

PubMed

Balázs, Tibor; Merkely, Béla; Bognár, Eszter; Zima, Endre

2013-04-01

The aim of our investigation was to examine the intraluminal interaction of the vascular tissue and the implanted coronary sinus lead stabilized with stent on two human hearts removed before transplantation. The coronary sinus lumen was sectioned under operational microscope and opened carefully. The leads and stents were found separately positioned beside each other completely covered by an intact intimal tissue layer. No sign of occluding proliferative tissue was observed. Stent fixation technique and extraction of the CS lead in our cases did not have any particular damaging effect on the vascular system. © 2012 Wiley Periodicals, Inc.

Comparison of self-expandable and balloon-expanding stents for hybrid ductal stenting in hypoplastic left heart complex.

PubMed

Goreczny, Sebastian; Qureshi, Shakeel A; Rosenthal, Eric; Krasemann, Thomas; Nassar, Mohamed S; Anderson, David R; Morgan, Gareth J

2017-07-01

We aimed to compare the procedural and mid-term performance of a specifically designed self-expanding stent with balloon-expandable stents in patients undergoing hybrid palliation for hypoplastic left heart syndrome and its variants. The lack of specifically designed stents has led to off-label use of coronary, biliary, or peripheral stents in the neonatal ductus arteriosus. Recently, a self-expanding stent, specifically designed for use in hypoplastic left heart syndrome, has become available. We carried out a retrospective cohort comparison of 69 neonates who underwent hybrid ductal stenting with balloon-expandable and self-expanding stents from December, 2005 to July, 2014. In total, 43 balloon-expandable stents were implanted in 41 neonates and more recently 47 self-expanding stents in 28 neonates. In the balloon-expandable stents group, stent-related complications occurred in nine patients (22%), compared with one patient in the self-expanding stent group (4%). During follow-up, percutaneous re-intervention related to the ductal stent was performed in five patients (17%) in the balloon-expandable stent group and seven patients (28%) in self-expanding stents group. Hybrid ductal stenting with self-expanding stents produced favourable results when compared with the results obtained with balloon-expandable stents. Immediate additional interventions and follow-up re-interventions were similar in both groups with complications more common in those with balloon-expandable stents.

Single-Center Experience and 1-Year Follow-up Results of 'Sandwich Technique' in the Management of Common Iliac Artery Aneurysms During EVAR

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ricci, Carmelo; Ceccherini, Claudio, E-mail: claudiocec@hotmail.it; Cini, Marco

Purpose: Abdominal aortic aneurysm (AAA) accompanied by common iliac artery (CIA) aneurysms requires a more demanding procedure owing to the difficulties in obtaining an adequate distal landing zone for the stent-graft limb(s), a potential site of endoleak. The 'sandwich technique' is a procedure to increase EVAR feasibility in the setting of adverse or challenging CIA anatomy. Its main advantages include no restrictions in terms of CIA diameter or length or internal iliac artery (IIA) diameter, no need to wait for a specific stent-graft. Our purpose is to describe our single-center experience and one year follow-up results of this new procedure.more » Materials and Methods: From April 2009 to June 2010, the sandwich technique was performed in our institution in 7 patients treated for AAA and unilateral CIA aneurysms (n. 5) or bilateral CIA aneurysms (n. 2). Inclusion criteria were the presence of unilateral or bilateral CIA aneurysm (independently from its diameter), IIA artery measuring up to 9 mm in its maximum diameter, not dilatation of IIA and EIA. Results: The mean follow-up length was 15 months (range: 14-20 months). All stent-implanted iliac branches remained patent on 1 year follow-up and IIA flow was preserved. None of the patients had symptoms of pelvic ischemia. CT scan follow-up showed aneurysm shrinkage in five patients, without any sign of endoleaks in all cases. Conclusions: In selected cases, the 'sandwich technique' showed good outcomes confirming to be a safe and easy to perform way to overcome anatomical constraints and expanding the limits of EVAR.« less

Behaviour of two typical stents towards a new stent evolution.

PubMed

Simão, M; Ferreira, J M; Mora-Rodriguez, J; Fragata, J; Ramos, H M

2017-06-01

This study explores the analysis of a new stent geometry from two typical stents used to treat the coronary artery disease. Two different finite element methods are applied with different boundary conditions to investigate the stenosis region. Computational fluid dynamics (CFD) models including fluid-structure interaction are used to assess the haemodynamic impact of two types of coronary stents implantation: (1) type 1-based on a strut-link stent geometry and (2) type 2-a continuous helical stent. Using data from a recent clinical stenosis, flow disturbances and consequent shear stress alterations introduced by the stent treatment are investigated. A relationship between stenosis and the induced flow fields for the two types of stent designs is analysed as well as the correlation between haemodynamics and vessel wall biomechanical factors during the initiation and development of stenosis formation in the coronary artery. Both stents exhibit a good performance in reducing the obstruction artery. However, stent type 1 presents higher radial deformation than the type 2. This deformation can be seen as a limitation with a long-term clinical impact.

A Spanner in the works: the use of a new temporary urethral stent to relieve bladder outflow obstruction after prostate brachytherapy.

PubMed

Henderson, Alastair; Laing, Robert W; Langley, Stephen E M

2002-01-01

Assessment of the Spanner, a new temporary urethral stent to relieve bladder outflow obstruction and urinary symptoms after brachytherapy. Five patients with unusually severe urinary morbidity after (125)I brachytherapy were recruited. The mean time after implant was 40 days (range 25-90). Spanner intraprostatic stents were introduced using topical anesthetic without complication. All patients were able to void spontaneously with no post-void residual volume of urine. The flow rates increased in all cases (p=0.03) and the International Prostate Symptom Scores were significantly improved after stent insertion in all patients (p=0.03). All patients experienced some degree of pain or dysuria during stent use. Bladder outflow obstruction was effectively treated with the Spanner intraprostatic stent, however pain limited the use of the device in the early post-brachytherapy patient group. Pharmacotherapy, stent design modification, or smaller stent diameter may increase the utility of stents after brachytherapy.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Doros, Attila, E-mail: dorattila@yahoo.com; Nemeth, Andrea; Deak, Akos Pal

The role of covered stent in the management of biliary complications is not yet defined in liver transplant recipients. This Case Report presents a patient with anastomotic stricture and leakage with biloma treated with a covered stent 32 months following liver transplantation. Signs of in-stent restenosis developed 52 months following covered stent placement, which was resolved by balloon dilation. There were no complications during the interventions. The latest follow-up, at 69 months following primary and 19 months following secondary percutaneous intervention, shows a patent covered stent without any clinical or morphological sign of further restenosis. The clinical success with long-termmore » follow-up data suggests that covered stent implantation can be a rational, minimally invasive option for simultaneous treatment of bile duct stenosis and bile leak following liver transplantation in selected cases.« less

Enhanced bioactivity of Mg-Nd-Zn-Zr alloy achieved with nanoscale MgF2 surface for vascular stent application.

PubMed

Mao, Lin; Shen, Li; Chen, Jiahui; Wu, Yu; Kwak, Minsuk; Lu, Yao; Xue, Qiong; Pei, Jia; Zhang, Lei; Yuan, Guangyin; Fan, Rong; Ge, Junbo; Ding, Wenjiang

2015-03-11

Magnesium (Mg) alloys have revolutionized the application of temporary load-bearing implants as they meet both engineering and medical requirements. However, rapid degradation of Mg alloys under physiological conditions remains the major obstacle hindering the wider use of Mg-based implants. Here we developed a simple method of preparing a nanoscale MgF2 film on Mg-Nd-Zn-Zr (denoted as JDBM) alloy, aiming to reduce the corrosion rate as well as improve the biological response. The corrosion rate of JDBM alloy exposed to artificial plasma is reduced by ∼20% from 0.337 ± 0.021 to 0.269 ± 0.043 mm·y(-1) due to the protective effect of the MgF2 film with a uniform and dense physical structure. The in vitro cytocompatibility test of MgF2-coated JDBM using human umbilical vein endothelial cells indicates enhanced viability, growth, and proliferation as compared to the naked substrate, and the MgF2 film with a nanoscale flakelike feature of ∼200-300 nm presents a much more favorable environment for endothelial cell adhesion, proliferation, and alignment. Furthermore, the animal experiment via implantation of MgF2-coated JDBM stent to rabbit abdominal aorta confirms excellent tissue compatibility of the well re-endothelialized stent with no sign of thrombogenesis and restenosis in the stented vessel.

A novel balloon assisted two-stents telescoping technique for repositioning an embolized stent in the pulmonary conduit.

PubMed

Kobayashi, Daisuke; Gowda, Srinath T; Forbes, Thomas J

2014-08-01

A 9-year-old male, with history of pulmonary atresia and ventricular septal defect, status post complete repair with a 16 mm pulmonary homograft in the right ventricular outflow tract (RVOT) underwent 3110 Palmaz stent placement for conduit stenosis. Following deployment the stent embolized proximally into the right ventricle (RV). We undertook the choice of repositioning the embolized stent into the conduit with a transcatheter approach. Using a second venous access, the embolized stent was carefully maneuvered into the proximal part of conduit with an inflated Tyshak balloon catheter. A second Palmaz 4010 stent was deployed in the distal conduit telescoping through the embolized stent. The Tyshak balloon catheter was kept inflated in the RV to stabilize the embolized stent in the proximal conduit until it was successfully latched up against the conduit with the deployment of the overlapping second stent. One year later, he underwent Melody valve implantation in the pre-stented conduit relieving conduit insufficiency. This novel balloon assisted two-stents telescoping technique is a feasible transcatheter option to secure an embolized stent from the RV to the RVOT. © 2014 Wiley Periodicals, Inc.

Imaging vascular implants with optical coherence tomography

NASA Astrophysics Data System (ADS)

Barton, Jennifer K.; Dal Ponte, Donny B.; Williams, Stuart K.; Ford, Bridget K.; Descour, Michael R.

2000-04-01

Vascular stents and grafts have many proven and promising clinical applications, but also a large number of complications. A focus of current research is the development of biocompatible implants. Evaluation of these devices generally requires a large number of animals due to the need for explanation and histological evaluation of the implant at several time intervals. It would be desirable to use instead a high resolution, in situ assessment method. An in vitro study was performed to determine if OCT could image cell proliferation and thrombus formation on vascular stents and grafts. First, images were taken of explanted stents. The implants were locate din peripheral vessels of a porcine model of atherosclerosis. The images clearly show the vessel response to initial damage, the materials of the implant, extent of intimal cell hyper proliferation, and small platelet aggregates. Next, a tissue engineered graft, which had been sodded with smooth muscle cells and incubated in a bioreactor, was evaluated. Cross-section images showed the pores of the polymer material and the layer of smooth muscle cells beginning to invade the graft material. For comparison, in vitro 20 MHz IVUS images of the same grafts were obtained. A catheter was designed for intravascular imaging. The 2.3 mm diameter catheter contains a fiber with GRIN lens and right angle prism, a monorail guidewire, and a novel positioning wire that can be protruded to push the catheter against the vessel wall, potentially eliminating the need for saline flush. Preliminary in vitro results with this catheter are encouraging.

Rotational atherectomy ablation for an unexpandable stent under the guide of IVUS

PubMed Central

Si, Daoyuan; Liu, Guohui; Tong, Yaliang; He, Yuquan

2018-01-01

Abstract Rationale: Inadequate stent expansion due to rigid calcified may result in restenosis lesions, but the available options are limited. Patient concerns: We report a case via the trans-radial approach of the severely underexpanded freshly deployed stent due to heavily calcified plaques Diagnoses: Coronary angiography revealed that there was no adequate expansion of the freshly deployed stent. Interventions: Under the guide of intravascular ultrasound (IVUS), rotational atherectomy (RA) successfully ablated the stent layers and the protruding calcified plaque. Followed by balloon angioplasty, the ablated segment was scaffolded with another stent, well expanded and documented by IVUS. Outcomes: The patient was uneventful during the procedure and remained angina free at the point of one year of clinical follow-up. Lessons: This case indicated that RA via the trans-radial approach could be a useful remedy in the situation of under-expansion of implanted stents, and the debulking should be performed under IVUS-guidance. PMID:29443790

Understanding the requirements of self-expandable stents for heart valve replacement: Radial force, hoop force and equilibrium.

PubMed

Cabrera, María Sol; Oomens, Cees W J; Baaijens, Frank P T

2017-04-01

A proper interpretation of the forces developed during stent crimping and deployment is of paramount importance for a better understanding of the requirements for successful heart valve replacement. The present study combines experimental and computational methods to assess the performance of a nitinol stent for tissue-engineered heart valve implantation. To validate the stent model, the mechanical response to parallel plate compression and radial crimping was evaluated experimentally. Finite element simulations showed good agreement with the experimental findings. The computational models were further used to determine the hoop force on the stent and radial force on a rigid tool during crimping and self-expansion. In addition, stent deployment against ovine and human pulmonary arteries was simulated to determine the hoop force on the stent-artery system and the equilibrium diameter for different degrees of oversizing. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Systematic isolated post-dilatation of the side branch as part of the provisional stent technique in the percutaneous treatment of coronary bifurcations. CR12 Registry.

PubMed

Jurado-Román, Alfonso; Rubio-Alonso, Belén; García-Tejada, Julio; Sánchez-Pérez, Ignacio; López-Lluva, María T; Gómez-Blázquez, Iván; Velázquez-Martín, María T; Albarrán-González-Trevilla, Agustín; Hernández-Hernández, Felipe; Lozano-Ruíz-Poveda, Fernando

2017-10-26

To analyse systematic isolated post-dilatation of the side branch as a part of provisional stent technique. 1960 angioplasties performed in two centres were prospectively registered, of which 382 were coronary bifurcations with a side branch>2mm. In centre A, isolated post-dilatation of the side branch was performed regardless its impairment after main vessel stenting. In centre B, side branch post-dilatation was performed only if it was severely affected after stent implantation. There was no difference between the two centres in the rate of side branch affection after stent implantation (A: 44.6 vs B: 49.3%, p=0.48) nor in the procedural success rate (A: 98.6% vs B: 96.7%, p=0.45). After one-year follow-up, a reduction of cardiovascular events was observed in centre A (A: 4.4% vs B: 10.4%, p=0.043) with a trend towards lower cardiac mortality (A: 2.2% vs B: 6.5%, p=0.093) and stent thrombosis (A: 0% vs B: 2.6%, p=0.077). There were no differences in the rate of myocardial infarction related to the treated artery (A: 1.4% vs B: 3.9%, p=0.29), or target lesion revascularization (A: 1.4% vs. B: 3.2%, p=0.45). Systematic isolated post-dilatation of the side branch in the provisional stent technique was associated with a high angiographic success rate, and a low rate of cardiovascular events during follow-up. Although the study design does not allow definitive conclusions, this strategy could be considered a valid option in some cases or even as part of the provisional stent technique. Copyright © 2017 Elsevier Inc. All rights reserved.

Safety of 6-month duration of dual antiplatelet therapy after percutaneous coronary intervention in patients with acute coronary syndromes: Rationale and design of the Smart Angioplasty Research Team-safety of 6-month duration of Dual Antiplatelet Therapy after percutaneous coronary intervention in patients with acute coronary syndromes (SMART-DATE) prospective multicenter randomized trial.

PubMed

Lee, Joo Myung; Cho, Deok-Kyu; Hahn, Joo-Yong; Song, Young Bin; Park, Taek Kyu; Oh, Ju-Hyeon; Lee, Jin Bae; Doh, Joon-Hyung; Kim, Sang-Hyun; Yang, Jeong Hoon; Choi, Jin-Ho; Choi, Seung-Hyuck; Lee, Sang Hoon; Gwon, Hyeon-Cheol

2016-12-01

Dual antiplatelet therapy (DAPT) is a fundamental treatment that optimizes clinical outcomes after percutaneous coronary intervention, especially in patients with acute coronary syndrome (ACS). Although current international guidelines recommend DAPT for at least 12 months after implantation of a drug-eluting stent in patients with ACS, these recommendations are not based on randomized controlled trials dedicated to ACS population. The SMART-DATE trial is a prospective, multicenter, randomized, and open-label study to demonstrate the noninferiority of 6-month DAPT compared with 12 months or longer DAPT in patients with ACS undergoing percutaneous coronary intervention. A total of 2,700 patients will undergo prospective, random assignment to either of the DAPT duration groups. To minimize the bias from different stent devices, the type of stents will be randomly assigned (everolimus-eluting stents, zotarolimus-eluting stents, or biolimus A9-eluting stents). The primary end point is a composite of all-cause death, myocardial infarction, and cerebrovascular events at 18 months after the index procedure. The major secondary end points are definite/probable stent thrombosis defined by the Academic Research Consortium and bleeding defined by Bleeding Academic Research Consortium type 2-5. The SMART-DATE randomized trial is the first study exploring the safety of 6-month DAPT compared with conventional 12-month or longer DAPT dedicated to patients with ACS after second-generation drug-eluting stent implantation. Copyright © 2016 Elsevier Inc. All rights reserved.

Comparison of Immediate With Delayed Stenting Using the Minimalist Immediate Mechanical Intervention Approach in Acute ST-Segment-Elevation Myocardial Infarction: The MIMI Study.

PubMed

Belle, Loic; Motreff, Pascal; Mangin, Lionel; Rangé, Grégoire; Marcaggi, Xavier; Marie, Antoine; Ferrier, Nadine; Dubreuil, Olivier; Zemour, Gilles; Souteyrand, Géraud; Caussin, Christophe; Amabile, Nicolas; Isaaz, Karl; Dauphin, Raphael; Koning, René; Robin, Christophe; Faurie, Benjamin; Bonello, Laurent; Champin, Stanislas; Delhaye, Cédric; Cuilleret, François; Mewton, Nathan; Genty, Céline; Viallon, Magalie; Bosson, Jean Luc; Croisille, Pierre

2016-03-01

Delayed stent implantation after restoration of normal epicardial flow by a minimalist immediate mechanical intervention aims to decrease the rate of distal embolization and impaired myocardial reperfusion after percutaneous coronary intervention. We sought to confirm whether a delayed stenting (DS) approach (24-48 hours) improves myocardial reperfusion, versus immediate stenting, in patients with acute ST-segment-elevation myocardial infarction undergoing primary percutaneous coronary intervention. In the prospective, randomized, open-label minimalist immediate mechanical intervention (MIMI) trial, patients (n=140) with ST-segment-elevation myocardial infarction ≤12 hours were randomized to immediate stenting (n=73) or DS (n=67) after Thrombolysis In Myocardial Infarction 3 flow restoration by thrombus aspiration. Patients in the DS group underwent a second coronary arteriography for stent implantation a median of 36 hours (interquartile range 29-46) after randomization. The primary end point was microvascular obstruction (% left ventricular mass) on cardiac magnetic resonance imaging performed 5 days (interquartile range 4-6) after the first procedure. There was a nonsignificant trend toward lower microvascular obstruction in the immediate stenting group compared with DS group (1.88% versus 3.96%; P=0.051), which became significant after adjustment for the area at risk (P=0.049). Median infarct weight, left ventricular ejection fraction, and infarct size did not differ between groups. No difference in 6-month outcomes was apparent for the rate of major cardiovascular and cerebral events. The present findings do not support a strategy of DS versus immediate stenting in patients with ST-segment-elevation infarction undergoing primary percutaneous coronary intervention and even suggested a deleterious effect of DS on microvascular obstruction size. URL: http://www.clinicaltrials.gov. Unique identifier: NCT01360242. © 2016 American Heart Association, Inc.

Stage of hilar cholangiocarcinoma predicts recurrence of biliary obstruction in patients with metal stents.

PubMed

Siddiqui, Ali; Shahid, Haroon; Sarkar, Avik; Cox, Kristen; Kowalski, Thomas E; Loren, David E; Sharma, Ashish; Laing, Patrick; Birch, Madeline; Adler, Douglas G

2013-09-01

Most patients with hilar cholangiocarcinomas present with unresectable tumors, so only palliative biliary drainage with self-expanding metal stents (SEMS) is possible. Stents eventually cease to function because of tumor overgrowth and/or other causes, so it is important to identify factors that affect stent patency and failure. We examined the patency of endoscopically placed SEMS in patients with hilar cholangiocarcinoma and factors associated with patency. We performed a retrospective study of 120 consecutive patients (mean age, 67 ± 14.6 years; 74 male) who presented with obstructive jaundice from hilar cholangiocarcinoma and underwent bilateral SEMS from September 2006 through April 2012 at 2 US tertiary medical centers. We collected data on patient demographics and survival, success of stent placement and function, and immediate adverse events. The primary outcome was duration of stent patency (time from insertion to failure). Thirty-eight patients had stage 1 hilar cholangiocarcinomas, 45 had stage 2, 12 had stage 3, and 25 had stage 4. The median length of the hilar stricture was 9 mm (range, 8-50 mm). The stent was successfully passaged across the stricture in all patients and was functional in 115; its median length was 8 mm (range, 8-10 mm), and diameter was 80 mm (range, 60-100 mm). Fourteen patients had immediate adverse events, including perforation (n = 2), bleeding (n = 2), pancreatitis (n = 9), and cholangitis (n = 1). Median survival was 17 weeks (range, 1-211 weeks), and 50 patients had stent occlusion. On Kaplan-Meier analysis, the median time from stent placement to occlusion was 17 weeks (range, 1-104 weeks). More patients with stage 3 or 4 tumors (64%) had SEMS occlusion than patients with stage 1 or 2 tumors (28%) in univariate analysis (P = .017). In multivariate analysis, only cancer stage was independently and significantly associated with patency (P = .006; hazard ratio, 2.77); age, sex, length of stricture, and SEMS diameter and length were not. The cumulative patency of bilateral SEMS for hilar cholangiocarcinoma significantly decreases as tumor stage increases. Age, sex, length of stricture, and SEMS diameter and length are not associated with SEMS patency. Copyright © 2013 AGA Institute. Published by Elsevier Inc. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lanciego, Carlos; Rodriguez, Mario; Rodriguez, Adela

The use of metallic stents in the management of benign and malignant superior vena cava syndrome (SVCS) is well documented. Symptomatic stenosis or occlusion of the SVC is a rare complication of a transvenous permanent pacemaker implant. Suggested treatments have included anticoagulation therapy, thrombolysis, balloon angioplasty and surgery. More recently, endovascular stenting has evolved as an attractive alternative but the data available in the literature are limited. We describe a case in which venous stenting with a Wallstent endoprosthesis was used successfully. The patient remains symptom free and with normal pacemaker function 36 months later.

High-Resolution CT and Angiographic Evaluation of NexStent Wall Adaptation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nemes, Balazs, E-mail: nembal@freemail.hu; Lukacs, Levente; Balazs, Gyoergy

2009-05-15

Carotid stenting is a minimally invasive treatment for extracranial carotid artery stenosis. Stent design may affect technical success and complications in a certain subgroup of patients. We examined the wall adaptability of a new closed-cell carotid stent (NexStent), which has a unique rolled sheet design. Forty-one patients had 42 carotid arteries treated with angioplasty and stenting for internal carotid artery stenosis. The mean patient age was 65 {+-} 10 years. All patients underwent high-resolution computed tomographic angiography after the stent implantation. Data analysis included pre- and postprocedural stenosis, procedure complications, plaque calcification, and stent apposition. We reviewed the angiographic andmore » computed tomographic images for plaque coverage and stent expansion. All procedures were technically successful. Mean stenosis was reduced from 84 {+-} 8% before the procedure to 15.7 {+-} 7% after stenting. Two patients experienced transient ischemic attack; one patient had bradycardia and hypotension. Stent induced kinking was observed in one case. Good plaque coverage and proper overlapping of the rolled sheet was achieved in all cases. There was weak correlation between the residual stenosis and the amount of calcification. The stent provides adequate expansion and adaptation to the tapering anatomy of the bifurcation.« less

Fabrication of Small Caliber Stent-grafts Using Electrospinning and Balloon Expandable Bare Metal Stents.

PubMed

Uthamaraj, Susheil; Tefft, Brandon J; Jana, Soumen; Hlinomaz, Ota; Kalra, Manju; Lerman, Amir; Dragomir-Daescu, Dan; Sandhu, Gurpreet S

2016-10-26

Stent-grafts are widely used for the treatment of various conditions such as aortic lesions, aneurysms, emboli due to coronary intervention procedures and perforations in vasculature. Such stent-grafts are manufactured by covering a stent with a polymer membrane. An ideal stent-graft should have a biocompatible stent covered by a porous, thromboresistant, and biocompatible polymer membrane which mimics the extracellular matrix thereby promoting injury site healing. The goal of this protocol is to manufacture a small caliber stent-graft by encapsulating a balloon expandable stent within two layers of electrospun polyurethane nanofibers. Electrospinning of polyurethane has been shown to assist in healing by mimicking native extracellular matrix, thereby promoting endothelialization. Electrospinning polyurethane nanofibers on a slowly rotating mandrel enabled us to precisely control the thickness of the nanofibrous membrane, which is essential to achieve a small caliber balloon expandable stent-graft. Mechanical validation by crimping and expansion of the stent-graft has shown that the nanofibrous polyurethane membrane is sufficiently flexible to crimp and expand while staying patent without showing any signs of tearing or delamination. Furthermore, stent-grafts fabricated using the methods described here are capable of being implanted using a coronary intervention procedure using standard size guide catheters.

Conformability of balloon-expandable stents to the carotid siphon: an in vitro study.

PubMed

du Mesnil de Rochemont, R; Yan, B; Zanella, F E; Rüfenacht, D A; Berkefeld, J

2006-02-01

Endovascular placement of coronary balloon-expandable stents in patients with recurrent cerebral ischemia has emerged as a treatment option for intracranial arterial occlusive disease. We have developed an in vitro model matching the tortuous curve of the carotid siphon that allows the assessment of apposition of stents to a curved vessel wall. Six types of balloon-expandable coronary stents were implanted in a silicone model of the carotid siphon. Digital radiographs and 3D rotational angiograms were obtained. Stent morphology was evaluated and the degree of apposition between stent and wall of the model was measured on a digital workstation. All 6 stents showed lack of apposition between stent and the wall at the convexity of the anterior segment of the carotid siphon and the wall at the concavity at both extremities of the stent. In and around the curve, the modules of the stents did not expand completely to their nominal diameter and were distorted to an oval shape. The tested coronary balloon-expandable stents did not completely conform to the vessel wall of the model of the carotid siphon and further development is needed to approach the goal of an "ideal intracranial stent."

Fenestration of a Papyrus PK covered stent to recover the occluded left main bifurcation after sealing a left main perforation during a CTO procedure.

PubMed

Werner, Gerald S; Ahmed, Waqar H

2017-09-01

Covered stents are indicated for coronary perforations, but they may seal off major side branches in that process. We report the successful sealing of an ostial left main perforation, induced by a guide catheter in the course of a retrograde approach to treat a chronic total occlusion (CTO) of the right coronary artery (RCA) in a 76year old woman with prior CABG. The implanted Papyrus covered stent, however, overlapped the left main bifurcation and occluded the non-grafted circumflex artery (CX) resulting in acute ischemia. Through a double lumen catheter advanced over the wire located in the left anterior descending coronary artery (LAD) territory, a stiff recanalization wire could be advanced from the side-port to penetrate the stent membrane towards the CX. This was successfully achieved, and after subsequent dilatation, a drug-eluting stent was implanted in Culotte-fashion from the CX to the left main with subsequent kissing-balloon dilatation. The clinical symptoms subsided immediately, and the RCA was finally recanalized in antegrade parallel wire technique. No periprocedural infarct was observed during 48h of follow-up before discharge. At clinical follow-up of 6months the patient is symptom-free. Copyright © 2017 Elsevier Inc. All rights reserved.

Is In-Stent Restenosis After a Successful Coronary Stent Implantation Due to Stable Angina Associated With TG/HDL-C Ratio?

PubMed

Kundi, Harun; Korkmaz, Ahmet; Balun, Ahmet; Cicekcioglu, Hulya; Kiziltunc, Emrullah; Gursel, Koray; Cetin, Mustafa; Ornek, Ender; Ileri, Mehmet

2017-10-01

We examined the impact of the preprocedural triglyceride (TG)/high-density lipoprotein cholesterol (HDL-C) ratio on risk of in-stent restenosis (ISR). Patients with typical anginal symptoms and/or positive treadmill or myocardial perfusion scintigraphy test results who underwent successful coronary stent implantation due to stable angina were examined; 1341 patients were enrolled. The hospital files of the patients were used to gather data. Cox regression analysis showed that the TG/HDL-C ratio was independently associated with the presence of ISR ( P < .001). Moreover, diabetes mellitus ( P = .007), smaller stent diameter ( P = .046), and smoking status ( P = .001) were also independently associated with the presence of ISR. Using a cutoff of 3.8, the TG/HDL-C ratio predicted the presence of ISR with a sensitivity of 71% and a specificity of 68%. Also, the highest quartile of TG/HDL-C ratio had the highest rate of ISR ( P < .001). Measuring preprocedural TG/HDL-C ratio, in fasting or nonfasting samples, could be beneficial for the risk assessment of ISR. However, further large-scale prospective studies are required to establish the exact role of this simple, easily calculated, and reproducible parameter in the pathogenesis of ISR.

Self-Expanding Versus Balloon-Expandable Stents for Iliac Artery Occlusive Disease: The Randomized ICE Trial.

PubMed

Krankenberg, Hans; Zeller, Thomas; Ingwersen, Maja; Schmalstieg, Josefin; Gissler, Hans Martin; Nikol, Sigrid; Baumgartner, Iris; Diehm, Nicolas; Nickling, Estell; Müller-Hülsbeck, Stefan; Schmiedel, Rainer; Torsello, Giovanni; Hochholzer, Willibald; Stelzner, Christian; Brechtel, Klaus; Ito, Wulf; Kickuth, Ralph; Blessing, Erwin; Thieme, Marcus; Nakonieczny, Jaroslaw; Nolte, Thomas; Gareis, Ragnar; Boden, Harald; Sixt, Sebastian

2017-08-28

Atherosclerosis of iliac arteries is widespread. As inflow vessels, they are of great clinical significance and increasingly being treated by endovascular means. Most commonly, stents are implanted. So far, due to a lack of comparative data, no guideline recommendations on the preferable stent type, balloon-expandable stent (BE) or self-expanding stent (SE), have been issued. In this randomized, multicenter study, patients with moderate to severe claudication from common or external iliac artery occlusive disease were assigned 1:1 to either BE or SE. The primary endpoint was binary restenosis at 12 months as determined by duplex ultrasound. Key secondary endpoints were walking impairment, freedom from target lesion revascularization (TLR), hemodynamic success, target limb amputation, and all-cause death. Six hundred sixty patients with 660 lesions were enrolled at 18 German and Swiss sites over a period of 34 months; 24.8% of the patients had diabetes and 57.4% were current smokers. The common iliac artery was affected in 58.9%. One hundred nine (16.5%) lesions were totally occluded and 25.6% heavily calcified. Twelve-month incidence of restenosis was 6.1% after SE implantation and 14.9% after BE implantation (p = 0.006). Kaplan-Meier estimate of freedom from TLR was 97.2% and 93.6%, respectively (p = 0.042). There was no between-group difference in walking impairment, hemodynamic success, amputation rate, all-cause death, or periprocedural complications. The treatment of iliac artery occlusive disease with SE as compared with BE resulted in a lower 12-month restenosis rate and a significantly reduced TLR rate. No safety concerns arose in both groups. (Iliac, Common and External [ICE] Artery Stent Trial; NCT01305174). Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Use of drug-eluting stents in Victorian public hospitals.

PubMed

Yan, Bryan P; Ajani, Andrew E; Duffy, Stephen J; New, Gishel; Horrigan, Mark; Szto, Gregory; Walton, Antony; Eccleston, David; Lefkovits, Jeffery; Black, Alexander; Sebastian, Martin; Brennan, Angela L; Reid, Christopher M; Clark, David J

2006-10-02

We aimed to assess the pattern of use of drug-eluting stents (DESs) in patients undergoing percutaneous coronary interventions (PCIs) in Victorian public hospitals. Prospective study comparing the use of one or more DESs versus bare-metal stents (BMSs) only, in consecutive patients undergoing 2428 PCIs with stent implantation from 1 April 2004 to 31 December 2005 at seven Victorian public hospitals. Adherence to current Victorian Department of Human Services guidelines which recommend DES use in patients with high-risk features for restenosis (diabetes, small vessels, long lesions, in-stent restenotic lesions, chronic total occlusions and bifurcation lesions). Of the 2428 PCIs performed, at least one DES was implanted in 1101 (45.3%) and BMSs only were implanted in 1327 (54.7%). In 87.7% (966/1101) of PCI with DESs, there was at least one criterion for high risk of restenosis. DESs were more likely to be used in patients with diabetes (risk ratio [RR], 2.45; 95% CI, 2.02-2.97), small vessels (RR, 3.35; 95%CI, 2.35-4.76), long lesions (RR, 3.87; 95% CI, 3.23-4.65), in-stent restenotic lesions (RR, 3.98; 95%CI, 2.67-6.06), chronic total occlusions (RR, 1.30; 95% CI, 0.51-2.88) and bifurcation lesions (RR, 2.23; 95%CI, 1.57-3.17). However, 66.2% (1608/2428) of all PCIs were in patients eligible for DESs according to Victorian guidelines, and in 39.9% (642/1608) of these PCIs, a BMS was used. In Victorian public hospitals, DESs have been largely reserved for patients at high risk of restenosis in accordance with Department of Human Services guidelines. However, many patients with high-risk criteria for restenosis did not receive DESs. Greater use of DESs in these patients may improve outcomes by reducing the need for repeat revascularisation.

Effect of dissolution of magnesium alloy AZ31 on the rheological properties of Phosphate Buffer Saline.

PubMed

Riaz, Usman; Rakesh, Leela; Shabib, Ishraq; Haider, Waseem

2018-06-05

The issue of long-term incompatible interactions associated with the permanent implants can be eliminated by using various biodegradable metal implants. The recent research is focusing on the use of degradable stents to restore most of the hindrances of capillaries, and coronary arteries by supplying instant blood flow with constant mechanical and structural support. However, internal endothelialization and infection due to the corrosion of implanted stents are not easy to diagnose in the long run. In the recent past, magnesium (Mg) has been widely investigated for the cardiovascular stent applications. Here we made an attempt to understand the biodegradation process of Mg alloy stent by studying the degradation of Mg alloy AZ31 (3 wt% Aluminum, 1 wt% Zn) powder at various time-intervals in simulated blood fluid using the Rheological methods. The degradability of the Mg stent in the arteries affects the stress-strain properties of blood plasma and the subsequent flow conditions. Blood and plasma viscosities alter due to the degradation of Mg resulting from the stress-strain experienced in the blood vessels, in which the stent is inserted. Here our objective was to explore the influence of Mg degradation on the blood plasma viscosity by studying the viscoelastic properties. In this work, the effect of dissolution of Mg alloy AZ31 on the rheological properties of Phosphate Buffer Saline (PBS) at various time intervals have been investigated. The viscosity of the PBS-AZ31 solution increased with the dissolution of both slurries and percolated clear solution. The only exception was day-7 of the percolated clear solution, where viscosity was decreased showing a reduction in viscosity at initial stages of dissolution. The frequency sweep showed the tendency of the PBS-AZ31 gelation up to 100 rad/s frequency. Copyright © 2018 Elsevier Ltd. All rights reserved.

Experimental Evaluation of a New Single Wire Stainless Steel Fishscale Coronary Stent (Freedomª).

PubMed

Wang; Verbeken; Mukherjee; Zhou; De Scheerder IK

1996-10-01

Recent randomized clinical trials revealed a significant reduction in angiographic restenosis rates when adjunctive stenting was performed after conventional coronary balloon angioplasty. Current approved coronary stents are however hampered by their rigidity, limiting their trackability in tortuous vessels and furthermore, needing high pressure deployment for optimal vessel apposition. New coronary stents are currently under development, using more biocompatible metal alloys and/or designs which better align to the vessel wall at moderate deployment pressures. We evaluated the safety, efficacy, angiographic and histological effect of a new stainless steel fishscale designed stent (Freedomª, Global Therapeutics, Co., USA) in a porcine coronary and peripheral artery model. Implantation in the right coronary artery was successful in all 20 pigs. Control angiograms at 6 weeks follow-up demonstrated patent vessels and morphologic evaluation showed only a mild fibromuscular neointimal response resulting in an area stenosis of 28.7 +/- 0.18% and a mean neointimal hyperplasia of 0.18 +/- 0.25 mm. Comparison with the Palmaz-Schatzª coronary stent in a porcine peripheral artery model demonstrated similar quantitative angiographic and morphologic vessel analysis results. Also the morphometric data were comparable. Area stenosis: Palmaz-Schatz: 37 +/- 0.24%, Freedom: 21 +/- 0.14%, p = 0.07. Mean neointimal hyperplasia: Palmaz-Schatz: 0.33 +/- 0.24 mm, Freedom: 0.18 +/- 0.08 mm, p = 0.08. CONCLUSION: Freedom coronary stent implantation in a porcine model resulted in a high procedural success without subacute thrombotic occlusions, despite no further anticoagulation nor antiplatelet therapy. Six weeks histopathological and morphometric evaluation demonstrated only a mild fibromuscular neointimal hyperplasia.

Sensor to detect endothelialization on an active coronary stent

PubMed Central

2010-01-01

Background A serious complication with drug-eluting coronary stents is late thrombosis, caused by exposed stent struts not covered by endothelial cells in the healing process. Real-time detection of this healing process could guide physicians for more individualized anti-platelet therapy. Here we present work towards developing a sensor to detect this healing process. Sensors on several stent struts could give information about the heterogeneity of healing across the stent. Methods A piezoelectric microcantilever was insulated with parylene and demonstrated as an endothelialization detector for incorporation within an active coronary stent. After initial characterization, endothelial cells were plated onto the cantilever surface. After they attached to the surface, they caused an increase in mass, and thus a decrease in the resonant frequencies of the cantilever. This shift was then detected electrically with an LCR meter. The self-sensing, self-actuating cantilever does not require an external, optical detection system, thus allowing for implanted applications. Results A cell density of 1300 cells/mm2 on the cantilever surface is detected. Conclusions We have developed a self-actuating, self-sensing device for detecting the presence of endothelial cells on a surface. The device is biocompatible and functions reliably in ionic liquids, making it appropriate for implantable applications. This sensor can be placed along the struts of a coronary stent to detect when the struts have been covered with a layer of endothelial cells and are no longer available surfaces for clot formation. Anti-platelet therapy can be adjusted in real-time with respect to a patient's level of healing and hemorrhaging risks. PMID:21050471

The Management of Superior Mesenteric Artery Aneurysm: Experience with 16 Cases in a Single Center.

PubMed

Zilun, Li; Henghui, Yin; Yang, Zhao; Mian, Wang; Guangqi, Chang; Shenming, Wang

2017-07-01

Superior mesenteric artery aneurysm (SMAA) represents a rare but potentially fatal condition. This study aimed to present the individual management protocol of SMAA in our center and to discuss a potential preliminary treatment algorithm. SMAA patients treated in our center between January 2007 and December 2014 were retrospectively reviewed on January 2015. Sixteen patients with SMAA were identified, including 1 female and 15 males, with a mean age of 48.9 ± 12.9 years. Three patients (3/16, 18.8%) were treated by multiple overlapping bare stents and one (1/16, 6.3%) initially by a single bare stent. Two cases (2/16, 12.5%) were treated by a covered stent implantation, but one of those suffered from SMAA rupture 7 days later, whereas the other had inner-stent thrombosis one month after discharge and died from multiple organ-dysfunction syndrome. Nine patients (9/16, 56.2%) received conservative therapy, one of who received multiple overlapping bare stents implantations for persistent abdominal pain. One patient underwent open surgery. There were 2 major complications, with no death during hospitalization and 1 death during follow-up. SMAA treatment needs to be individually prescribed, based on clinical manifestation, anatomy, and etiology. Multiple overlapping bare stents are safe and effective in selective patients with SMAA, and covered stents should be used with caution to avoid covering proximal branches; open surgery should be reserved for patients with suspected intestinal necrosis. Copyright © 2017 Elsevier Inc. All rights reserved.

Stent thrombosis and bleeding complications after implantation of sirolimus-eluting coronary stents in an unselected worldwide population: a report from the e-SELECT (Multi-Center Post-Market Surveillance) registry.

PubMed

Urban, Philip; Abizaid, Alexandre; Banning, Adrian; Bartorelli, Antonio L; Baux, Ana Cebrian; Džavík, Vladimír; Ellis, Stephen; Gao, Runlin; Holmes, David; Jeong, Myung Ho; Legrand, Victor; Neumann, Franz-Josef; Nyakern, Maria; Spaulding, Christian; Worthley, Stephen

2011-03-29

The aim of this study was to ascertain the 1-year incidence of stent thrombosis (ST) and major bleeding (MB) in a large, unselected population treated with sirolimus-eluting stents (SES). Stent thrombosis and MB are major potential complications of drug-eluting stent implantation. Their relative incidence and predisposing factors among large populations treated worldwide are unclear. The SES were implanted in 15,147 patients who were entered in a multinational registry. We analyzed the incidence of: 1) definite and probable ST as defined by the Academic Research Consortium; and 2) MB, with the STEEPLE (Safety and efficacy of Enoxaparin in PCI) definition, together with their relation to dual antiplatelet therapy (DAPT) and to 1-year clinical outcomes. The mean age of the sample was 62 ± 11 years, 30.4% were diabetic, 10% had a Charlson comorbidity index ≥3, and 44% presented with acute coronary syndrome or myocardial infarction. At 1 year, the reported compliance with DAPT as recommended by the European Society of Cardiology guidelines was 86.3%. Adverse event rates were: ST 1.0%, MB 1.0%, mortality 1.7%, myocardial infarction 1.9%, and target lesion revascularization 2.3%. Multivariate analysis identified 9 correlates of ST and 4 correlates of MB. Advanced age and a high Charlson index were associated with an increased risk of both ST and MB. After ST, the 7-day and 1-year all-cause mortality was 30% and 35%, respectively, versus 1.5% and 10% after MB. Only 2 of 13,749 patients (0.015%) experienced both MB and ST during the entire 1-year follow-up period. In this worldwide population treated with ≥1 SES, the reported compliance with DAPT was good, and the incidence of ST and MB was low. Stent thrombosis and MB very rarely occurred in the same patient. (The e-SELECT Registry: a Multicenter Post-Market Surveillance; NCT00438919). Copyright © 2011 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Effectiveness of two-year clopidogrel + aspirin in abolishing the risk of very late thrombosis after drug-eluting stent implantation (from the TYCOON [two-year ClOpidOgrel need] study).

PubMed

Tanzilli, Gaetano; Greco, Cesare; Pelliccia, Francesco; Pasceri, Vincenzo; Barillà, Francesco; Paravati, Vincenzo; Pannitteri, Gaetano; Gaudio, Carlo; Mangieri, Enrico

2009-11-15

It remains unclear whether dual antiplatelet therapy >12 months might carry a better prognosis after percutaneous coronary intervention (PCI) with drug-eluting stents (DESs). To address the hypothesis that in the real world the risk of very late thrombosis after PCI with DESs can be decreased by an extended use of clopidogrel, we set up the Two-Year ClOpidOgrel Need (TYCOON) registry and prospectively investigated the impact on very late thrombosis of 12- versus 24-month dual antiplatelet regimens in an unselected population. The registry enrolled 897 consecutive patients who underwent PCI with stenting from January 1, 2003, to December 31, 2004, and had dual antiplatelet therapy. All patients had a 4-year clinical follow-up. In the 447 patients with DES implantation, the dual antiplatelet regimen after PCI was given for 12 months in the 173 patients treated in 2003 (12-month group) and for 24 months in the 274 patients treated in 2004 (24-month group). Comparison between groups did not reveal any significant difference in baseline clinical characteristics, angiographic and procedural features, and major adverse cardiac events. During follow-up, there were 5 cases of stent thrombosis after PCI in the 12-month DES group and 1 case in the 24-month DES group (p = 0.02). Specifically, there were 2 cases of subacute thrombosis (1 in each group), no case of late thrombosis, and 4 cases of very late thrombosis occurring at 13, 15, 17, and 23 months after DES implantation in the 12-month group only. In conclusion, a 2-year dual antiplatelet regimen with aspirin and clopidogrel can prevent the occurrence of very late stent thrombosis after PCI with DESs.

Automatic three-dimensional registration of intravascular optical coherence tomography images

NASA Astrophysics Data System (ADS)

Ughi, Giovanni J.; Adriaenssens, Tom; Larsson, Matilda; Dubois, Christophe; Sinnaeve, Peter R.; Coosemans, Mark; Desmet, Walter; D'hooge, Jan

2012-02-01

Intravascular optical coherence tomography (IV-OCT) is a catheter-based high-resolution imaging technique able to visualize the inner wall of the coronary arteries and implanted devices in vivo with an axial resolution below 20 μm. IV-OCT is being used in several clinical trials aiming to quantify the vessel response to stent implantation over time. However, stent analysis is currently performed manually and corresponding images taken at different time points are matched through a very labor-intensive and subjective procedure. We present an automated method for the spatial registration of IV-OCT datasets. Stent struts are segmented through consecutive images and three-dimensional models of the stents are created for both datasets to be registered. The two models are initially roughly registered through an automatic initialization procedure and an iterative closest point algorithm is subsequently applied for a more precise registration. To correct for nonuniform rotational distortions (NURDs) and other potential acquisition artifacts, the registration is consecutively refined on a local level. The algorithm was first validated by using an in vitro experimental setup based on a polyvinyl-alcohol gel tubular phantom. Subsequently, an in vivo validation was obtained by exploiting stable vessel landmarks. The mean registration error in vitro was quantified to be 0.14 mm in the longitudinal axis and 7.3-deg mean rotation error. In vivo validation resulted in 0.23 mm in the longitudinal axis and 10.1-deg rotation error. These results indicate that the proposed methodology can be used for automatic registration of in vivo IV-OCT datasets. Such a tool will be indispensable for larger studies on vessel healing pathophysiology and reaction to stent implantation. As such, it will be valuable in testing the performance of new generations of intracoronary devices and new therapeutic drugs.

Shrinking the Supply Chain for Implantable Coronary Stent Devices.

PubMed

Moore, Sean S; O'Sullivan, Kevin J; Verdecchia, Francesco

2016-02-01

Stenting treatments for the management of disease in the heart, arterial and venous systems, biliary ducts, urethras, ureters, oesophageal tract and prostate have made enormous technical advances since their introduction into clinical use. The progression from metallic to polymer based bio-absorbable stents, coupled with the advances in additive manufacturing techniques, present a unique opportunity to completely re-envision the design, manufacture, and supply chain of stents. This paper looks at current stenting trends and proposes a future where the stent supply chain is condensed from ~150 days to ~20 min. The Cardiologist therefore has the opportunity to become a designer, manufacturer and user with patients receiving custom stents specific to their unique pathology that will be generated, delivered and deployed in the Cath-lab. The paper will outline this potentially revolutionary development and consider the technical challenges that will need to be overcome in order to achieve these ambitious goals. A high level overview of the generating eluting stents in situ program-GENESIS-is outlined including some early experimental work.

Surface characterization, in vitro and in vivo biocompatibility of Mg-0.3Sr-0.3Ca for temporary cardiovascular implant.

PubMed

Bornapour, M; Mahjoubi, H; Vali, H; Shum-Tim, D; Cerruti, M; Pekguleryuz, M

2016-10-01

Magnesium-based alloys are attractive candidate materials for medical applications. Our earlier work showed that the ternary Mg-0.3Sr-0.3Ca alloy exhibits slower degradation rates than both binary Mg-Sr and Mg-Ca alloys. The ternary alloy immersed in simulated body fluid (SBF) forms a compact surface layer of corrosion products that we hypothesized to be a Sr-substituted hydroxyapatite (HA). The main objectives of the current work are to understand the bio-degradation mechanism of Mg-0.3Sr-0.3Ca, to identify the exact nature of its protective layer and to evaluate the in vitro and in vivo biocompatibility of the alloy for cardiovascular applications. To better simulate the physiological environment, the alloy was immersed in SBF which was daily refreshed. Raman spectroscopy and X-Ray photoelectron spectroscopy (XPS) confirmed the formation of a thin, Sr-substituted HA layer at the interface between the alloy and the corrosion products. In vitro biocompatibility evaluated via indirect cytotoxicity assays using HUVECs showed no toxicity effect and ions extracted from Mg-0.3Sr-0.3Ca in fact increased the viability of HUVECs after one week. In vivo tests were performed by implanting a tubular Mg-0.3Sr-0.3Ca stent along with a WE43 control stent into the right and left femoral artery of a dog. Post implantation and histological analyses showed no thrombosis in the artery with Mg-0.3Sr-0.3Ca stent after 5weeks of implantation while the artery implanted with WE43 stent was extensively occluded and thrombosed. Microscopic observation of the Mg-0.3Sr-0.3Ca implant-tissue interface confirmed the in situ formation of Sr-substituted HA on the surface during in vivo test. These results show that the interfacial layer protects the surface of the Mg-0.3Sr-0.3Ca alloy both in vitro and in vivo, and is the key factor in the bio-corrosion resistance of the alloy. Copyright © 2016 Elsevier B.V. All rights reserved.

Early Strut Coverage in Patients Receiving Drug-Eluting Stents and its Implications for Dual Antiplatelet Therapy: A Randomized Trial.

PubMed

Lee, Seung-Yul; Kim, Jung-Sun; Yoon, Hyuck-Jun; Hur, Seung-Ho; Lee, Sang-Gon; Kim, Jin Won; Hong, Young Joon; Kim, Ki-Seok; Choi, So-Yeon; Shin, Dong-Ho; Nam, Chung-Mo; Kim, Byeong-Keuk; Ko, Young-Guk; Choi, Donghoon; Jang, Yangsoo; Hong, Myeong-Ki

2018-02-09

This study sought to measure early strut coverage in patients receiving drug-eluting stents (DESs) and to explore the feasibility of short-term dual antiplatelet therapy (DAPT) based on the degree of early strut coverage. Data for early strut coverage in patients receiving new-generation DESs, and its implications for DAPT continuation were limited. A randomized, multicenter trial was conducted in 894 patients treated with DESs. Patients were randomly assigned to everolimus-eluting stent (EES) (n = 444) or biolimus-eluting stent (BES) (n = 450) groups and optical coherence tomography (OCT)-guided (n = 445) or angiography-guided (n = 449) implantation groups using a 2-by-2 factorial design. Early strut coverage was measured as the percentage of uncovered struts on 3-month follow-up OCT examination. The primary outcome was the difference in early strut coverage between EES and BES groups and between OCT- and angiography-guided implantation groups. The secondary outcome was a composite of cardiac death, myocardial infarction, stent thrombosis, and major bleeding during the first 12 months post-procedure in patients receiving 3-month DAPT based on the presence of early strut coverage (≤6% uncovered) on 3-month follow-up OCT. Three-month follow-up OCT data were acquired for 779 patients (87.1%). The median percentage of uncovered struts at 3 months was 8.9% and 8.2% in the EES and BES groups, respectively (p = 0.69) and was lower in the OCT-guided group (7.5%) than in the angiography-guided group (9.9%; p = 0.009). Favorable early strut coverage (≤6% uncovered strut) was observed in 320 of 779 patients (41.1%). At 12 months, the composite event rarely occurred in the 3-month (0.3%) or 12-month (0.2%) DAPT groups (p = 0.80). OCT-guided DES implantation improved early strut coverage compared with angiography-guided DES implantation, with no difference in strut coverage between EES and BES groups. Short-term DAPT may be feasible in selected patients with favorable early strut coverage (Determination of the Duration of the Dual Antiplatelet Therapy by the Degree of the Coverage of The Struts on Optical Coherence Tomography From the Randomized Comparison Between Everolimus-eluting Stents Versus Biolimus A9-eluting Stents [DETECT-OCT]; NCT01752894). Copyright © 2018 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Acceptance and introduction of disruptive technologies - simple steps to build a fully functional pulmonary valved stent.

PubMed

Huber, Christoph H; Marty, Bettina; von Segesser, Ludwig K

2007-08-01

Valved stents are new land for cardiac surgeons even though they are being used more frequently by interventional disciplines. This paper presents simple steps to build a patient-specific pulmonary valved stent and its delivery device. The design concept was tested by random participants at a med-tech meeting. The valved stent is constructed by linking an endoprosthetic graft with a valved-jugular-vein. The delivery device is made from a modified 5-ml syringe. Of 72 participants, 66 (92%) built and 60 participants implanted the device successfully into the targeted pulmonary position via a trans-infundibular access.

Effectiveness of early ureteric stenting for urosepsis associated with urinary tract calculi.

PubMed

Nishiguchi, Sho; Branch, Joel; Suganami, Yu; Kitagawa, Izumi; Tokuda, Yasuharu

2014-01-01

Patients with urosepsis associated with urinary tract calculi occasionally require drainage, primarily via ureteric stenting. Such patients require longer hospitalization. However, the indications for early ureteric stenting for this condition have not been clearly defined. To compare the length of stay (LOS) in the hospital between patients treated with earlier ureteric stenting versus those with delayed ureteric stenting. Design: Retrospective cohort study. Setting: An acute care teaching hospital in Japan. Length of hospital stay in days. Patients Patients with urosepsis associated with urinary tract calculi. Among a total of 30 patients (mean age, 72; 13 men), the mean number of days from emergency room admission to ureteric stenting was 3.5 days (range, 1-14 days), and the overall mean LOS was 36 days (range, 8-102 days). The early stenting group (mean LOS, 21 days) had a significantly shorter LOS than the delayed stenting group (mean LOS, 50 days), with an adjusted beta coefficient of -26 days [95% confidence interval (CI), -46, -6]. In patients with urosepsis associated with urinary tract calculi, performing early stenting within two days of admission may reduce the LOS in the hospital.

Measurement of in vitro and in vivo stent geometry and deformation by means of 3D imaging and stereo-photogrammetry.

PubMed

Zwierzak, Iwona; Cosentino, Daria; Narracott, Andrew J; Bonhoeffer, Philipp; Diaz, Vanessa; Fenner, John W; Schievano, Silvia

2014-12-01

To quantify variability of in vitro and in vivo measurement of 3D device geometry using 3D and biplanar imaging. Comparison of stent reconstruction is reported for in vitro coronary stent deployment (using micro-CT and optical stereo-photogrammetry) and in vivo pulmonary valve stent deformation (using 4DCT and biplanar fluoroscopy). Coronary stent strut length and inter-strut angle were compared in the fully deployed configuration. Local (inter-strut angle) and global (dog-boning ratio) measures of stent deformation were reported during stent deployment. Pulmonary valve stent geometry was assessed throughout the cardiac cycle by reconstruction of stent geometry and measurement of stent diameter. Good agreement was obtained between methods for assessment of coronary stent geometry with maximum disagreement of +/- 0.03 mm (length) and +/- 3 degrees (angle). The stent underwent large, non-uniform, local deformations during balloon inflation, which did not always correlate with changes in stent diameter. Three-dimensional reconstruction of the pulmonary valve stent was feasible for all frames of the fluoroscopy and for 4DCT images, with good correlation between the diameters calculated from the two methods. The largest compression of the stent during the cardiac cycle was 6.98% measured from fluoroscopy and 7.92% from 4DCT, both in the most distal ring. Quantitative assessment of stent geometry reconstructed from biplanar imaging methods in vitro and in vivo has shown good agreement with geometry reconstructed from 3D techniques. As a result of their short image acquisition time, biplanar methods may have significant advantages in the measurement of dynamic 3D stent deformation.

Ultrasound enhanced release of therapeutics from drug-releasing implants based on titania nanotube arrays.

PubMed

Aw, Moom Sinn; Losic, Dusan

2013-02-25

A non-invasive and external stimulus-driven local drug delivery system (DDS) based on titania nanotube (TNT) arrays loaded with drug encapsulated polymeric micelles as drug carriers and ultrasound generator is described. Ultrasound waves (USW) generated by a pulsating sonication probe (Sonotrode) in phosphate buffered saline (PBS) at pH 7.2 as the medium for transmitting pressure waves, were used to release drug-loaded nano-carriers from the TNT arrays. It was demonstrated that a very rapid release in pulsatile mode can be achieved, controlled by several parameters on the ultrasonic generator. This includes pulse length, time, amplitude and power intensity. By optimization of these parameters, an immediate drug-micelles release of 100% that spans a desirable time of 5-50 min was achieved. It was shown that stimulated release can be generated and reproduced at any time throughout the TNT-Ti implant life, suggesting considerable potential of this approach as a feasible and tunable ultrasound-mediated drug delivery system in situ via drug-releasing implants. It is expected that this concept can be translated from an in vitro to in vivo regime for therapeutic applications using drug-releasing implants in orthopedic and coronary stents. Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.

Three dimensional rotational angiography for assessment of coronary arteries during melody valve implantation: introducing a technique that may improve outcomes.

PubMed

Pockett, C R; Moore, J W; El-Said, H G

2017-02-01

Adverse events from Melody valve implantation may be catastrophic. To date a role for three dimensional rotational angiography of the aortic root (3DRAA) during Melody valve implantation has not been established. To describe the role of 3DRAA in the assessment of Melody valve candidacy and to demonstrate that it may improve outcomes. All patients who underwent cardiac catheterisation for Melody valve implantation and 3DRAA between August 2013 and February 2015 were reviewed. 31 patients had 3DRAA with balloon sizing. Ten were deemed not Melody candidates (5 coronary compression, 2 aortic root distortion with cusp flattening, 2 RVOT was too large, and 1 had complex branch stenosis and a short landing zone). Of the 21 patients who were Melody candidates, 12 had conduits, 6 prosthetic valves and 3 native RVOTs. In patients with conduits, the technique of stenting the conduit prior to dilation was used after measuring the distance between the conduit and the coronary arteries on 3DRAA. In the Melody patients, we had 100% procedural success and no serious adverse events (coronary compression, tears, stent fracture or endocarditis). As a tool for case selection, 3DRAA may facilitate higher procedural success and decreased risk of serious adverse events. Furthermore, 3D rotational angiography allows stenting of the conduit prior to dilation, which may prevent tears and possibly endocarditis.

Update on perioperative care of the cardiac patient for noncardiac surgery.

PubMed

Ghadimi, Kamrouz; Thompson, Annemarie

2015-06-01

The current review will address key topics and recommendations of the recent 2014 update of the American College of Cardiology and American Heart Association clinical practice guideline for the perioperative cardiovascular evaluation and management of patients undergoing noncardiac surgery. The completely rewritten guideline provides a stepwise approach for the identification and management of patients at highest risk for major adverse cardiac events and discusses new or updated recommendations. For example, β-blockers should be continued perioperatively but treatment should not be initiated within 24 h of noncardiac surgery. Angiotensin-converting enzyme inhibitors should be continued, but if held, may be restarted as soon as feasible. Routine aspirin therapy is not recommended without previous coronary stent implantation or risk assessment for myocardial ischemia. Elective noncardiac surgery should not be performed within 30 days of bare metal stent or 12 months of drug-eluting stent implantation because of in-stent thrombosis as well as bleeding risk from dual antiplatelet therapy during surgery. Noncardiac surgery may be considered, however, in patients on antiplatelet agents 180 days after drug-eluting stent placement if risk of surgical delay exceeds risk of stent thrombosis from cessation of antiplatelet therapy. In conclusion, this review will discuss the important topics from the 2014 American College of Cardiology/American Heart Association guideline in order to provide the perioperative physician with the most recent evidence necessary to minimize major adverse cardiac events in patients undergoing noncardiac surgery.

An intriguing design concept to enhance the pulsatile fatigue life of self-expanding stents.

PubMed

Hsiao, Hao-Ming; Yin, Ming-Ting

2014-02-01

Intravascular stenting has emerged as the primary treatment for vascular diseases and has received great attention from the medical community since its introduction two decades ago. The endovascular self-expanding stent is used to treat peripheral artery diseases; however, once implanted, these stents suffer from various cyclic motions caused by pulsatile blood pressure and daily activities. Due to this challenging environment, fatigue performance has become a critical issue for stent design. In this paper, a simple yet intriguing concept of stent design aimed at enhancing pulsatile fatigue life is investigated. The concept of this design is to shift the highly concentrated stresses/strains away from the crown and re-distribute them along the stress-free bar arm by tapering its strut width. Finite element models were developed to evaluate the mechanical integrity and pulsatile fatigue resistance of the stent to various loading conditions. Results show that the fatigue safety factor jumped to 2.5-3.0 times that of the standard stent with constant strut width. This is astonishing considering that the stent profile and scaffolding were not compromised. The findings of this paper provide an excellent approach to the optimization of future stent design to greatly improve stent fatigue performance.

[Management of malignant and benign airway stenosis by stent implantation].

PubMed

Gyulai, Márton; Slavei, Krisztina; Pénzes, István; Strausz, János

2006-11-12

In the last few decades the different bronchoscopic procedures have gained an important role in the treatment of airway stenosis, and the number of implanted airway stents has also greatly increased. Between 1998 and 2004 the authors implanted altogether 108 airway prosthesis in 90 patients at the Institute of Pulmonology of Pest County. 58% of the patients were males, 42% females, the average age was 57.5 years, the average follow-up time was 7 months. On the basis of different etiology the patients were separated into two main groups. In 57% the airway stenosis was caused by malignant illnesses, in these cases stents can be used only with palliative purpose. However, in case of benign lesions they can offer a long-term solution and require an adequate follow-up of the patients. The authors' main aim was to get an overall picture of the interventions they had done by processing the data, with the help of the measurable characteristics that make possible to follow the airways' permeability and its changes. Analysing the results of the respiratory function and blood gas examinations they didn't find a significant difference inspite of the subjective improvement.

A novel side branch protection technique in coronary stent implantation: Jailed Corsair technique.

PubMed

Numasawa, Yohei; Sakakura, Kenichi; Yamamoto, Kei; Yamamoto, Shingo; Taniguchi, Yousuke; Fujita, Hideo; Momomura, Shin-Ichi

2017-06-01

Side branch occlusion, which was one of the common complications in percutaneous coronary interventions, was closely associated with cardiac death and myocardial infarction. Clinical guidelines also support the importance of preservation of physiologic blood flow in SB during PCI to bifurcation lesions. In order to avoid side branch occlusion during stent implantation, we often performed the jailed wire technique, in which a conventional guide wire was inserted to the side branch before stent implantation to the main vessel. However, the jailed wire technique could not always prevent side branch occlusion. In this case report, we described a case of 72-year-old male suffering from angina pectoris. Coronary angiography revealed the diffuse calcified stenosis in the proximal and middle of left anterior descending coronary artery, and the large diagonal branch originated from the middle of the stenosis. To prevent side branch occlusion, we performed a novel side branch protection technique by using the Corsair microcatheter (Asahi Intecc, Nagoya, Japan). In this case report, we illustrated this "Jailed Corsair technique", and discussed the advantage compared to other side branch protection techniques such as the jailed balloon technique. Copyright © 2017 Elsevier Inc. All rights reserved.

Coagulation and complement activation.

PubMed

Christensen, K; Larsson, R; Emanuelsson, H; Elgue, G; Larsson, A

2001-02-01

The purpose of this investigation was to assess the effect of heparin coating of a new stent construction (Stent Graft, Jomed Implantate GmbH, Germany) on platelet and coagulation activity. Stent grafts with an ePTFE membrane interfoliated between two stents were deployed in tubings to form Chandler loops. Fresh human blood with a low concentration of heparin was rotated for 1 h, then collected and used for measurements of platelet number, thrombin-antithrombin complex (TAT), CD11b, C3a and C5b-9. There were five study groups: Group 1, conventional unmodified stents (n = 8); Group 2, untreated stent grafts (n = 8); Group 3, heparin-coated stents and untreated membrane (n = 7); Group 4, heparin-coated stents and membrane (n = 8); Group 5, heparin-coated PVC tubings with no stents (n = 8). There was a significant drop in platelet count, increase in TAT-values and CD11b expression in Groups 1-3 but not in Group 4 compared to Group 5. Examination by scanning electron microscopy revealed extensive activation on non-modified stents but almost no deposition of thrombotic material on heparin-modified stent grafts. With unmodified stents and membrane there were signs of significant activation of platelets and coagulation. In contrast, the heparin-coated stent graft induced much less alterations, indicating improved blood compatibility.

Surface modification of traditional and bioresorbable metallic implant materials for improved biocompatibility

NASA Astrophysics Data System (ADS)

Walker, Emily K.

Due to their strength, elasticity, and durability, a variety of metal alloys are commonly used in medical implants. Traditionally, corrosion-resistant metals have been preferred. These permanent materials can cause negative systemic and local tissue effects in the long-term. Permanent stenting can lead to late-stent thrombosis and in-stent restenosis. Metallic pins and screws for fracture fixation can corrode and fail, cause loss of bone mass, and contribute to inflammation and pain at the implant site, requiring reintervention. Corrodible metallic implants have the potential to prevent many of these complications by providing transient support to the affected tissue, dissolving at a rate congruent with the healing of the tissue. Alloys of iron and manganese (FeMn) exhibit similar fatigue strength, toughness, and elasticity compared with 316L stainless steel, making them very attractive candidates for bioresorbable stents and temporary fracture fixation devices. Much attention in recent years has been given to creating alloys with ideal mechanical properties for various applications. Little work has been done on determining the blood compatibility of these materials or on examining how their surfaces can be improved to improve cell adhesion, however. We examined thethrombogenic response of blood exposed to various resorbable ferrous stent materials through contact with porcine blood. The resorbable materials induced comparable or lower levels of several coagulation factors compared with 316L stainless steel. Little platelet adhesion was observed on any of the tested materials. Endothelialization is an important process after the implantation of a vascular stent, as it prevents damage to the vessel wall that can accelerate neointimal hyperplasia. Micromotion can lead to the formation of fibrous tissue surrounding an orthopedic implant, loosening, and ultimately failure of the implant. Nanoscale features were created on the surfaces of noble metal coatings, silicon, and bioabsorbable materials through ion beam irradiation in order to improve endothelialzation and bone cell adhesion. Gold, palladium, silicon, and iron manganese surfaces were patterned through ion beam irradiation using argon ions. The surface morphology of the samples was examined using atomic force microscopy (AFM) and scanning electron microscopy (SEM), while surface chemistry was examined through x-ray photoelectron spectroscopy (XPS) and contact angle goniometry measurements. It was not possible to create nanoscale surface features on the surfaces of the gold and palladium films. At near normal incidence, irradiation produced ripples on the surfaces of Si(100), while oblique incidence irradiation produced nanoislands in the presence of impurities on the surface. Iron manganese irradiation resulted in the formation of blade-shaped structures for ion energies between 500eV and 1000eV, and significant iron enrichment at the surface. Chemical treatment can also be used to create surface features that will enhance cell adhesion. Ti6Al4V is one of the most commonly used alloys for permanent orthopedic devices. The creation of a porous surface in order to improve osteoblast adhesion was achieved through chemical etching using acid-peroxide solutions. While phosphoric acid etched the grain boundaries, sulfuric and nitric acid preferentially etched grains of particular orientations, creating a spongy, porous morphology that has the potential to aid in osseointegration.

A new polymer-free drug-eluting stent with nanocarriers eluting sirolimus from stent-plus-balloon compared with bare-metal stent and with biolimus A9 eluting stent in porcine coronary arteries.

PubMed

Takimura, Celso K; Galon, Micheli Z; Gutierrez, Paulo S; Sojitra, Prakash; Vyas, Ashwin; Doshi, Manish; Lemos, Pedro A

2015-04-01

Permanent polymers in first generation drug-eluting stent (DES) have been imputed to be a possible cause of persistent inflammation, remodeling, malapposition and late stent thrombosis. We aim to describe the in vivo experimental result of a new polymer-free DES eluting sirolimus from stent-plus-balloon (Focus np stent, Envision Scientific) compared with a bare-metal stent (BMS) (Amazonia CroCo, Minvasys) and with a biolimus A9 eluting stent (Biomatrix, Biosensors). In 10 juvenile pigs, 23 coronary stents were implanted in the coronary arteries (8 Amazonia CroCo, 8 Focus np, and 7 Biomatrix). At 28-day follow-up, optical coherence tomography (OCT) and histology were used to evaluate neointimal hyperplasia and healing response. According to OCT analysis, Focus np stents had a greater lumen area and less neointimal hyperplasia response than BMS and Biomatrix had. Histomorphometry results showed less neointimal hyperplasia in Focus np than in BMS. Histology showed a higher fibrin deposition in Biomatrix stent compared to Focus np and BMS. The new polymer-free DES with sirolimus eluted from stent-plus-balloon demonstrated safety and reduced neointimal proliferation compared with the BMS and Biomatrix stents at 28-day follow-up in this porcine coronary model. This new polymer-free DES is promising and warrants further clinical studies.

Endoscopic and Photodynamic Therapy of Cholangiocarcinoma

PubMed Central

Meier, Benjamin; Caca, Karel

2016-01-01

Background Most patients with cholangiocarcinoma (CCA) have unresectable disease. Endoscopic bile duct drainage is one of the major objectives of palliation of obstructive jaundice. Methods/Results Stent implantation using endoscopic retrograde cholangiography is considered to be the standard technique. Unilateral versus bilateral stenting is associated with different advantages and disadvantages; however, a standard approach is still not defined. As there are various kinds of stents, there is an ongoing discussion on which stent to use in which situation. Palliation of obstructive jaundice can be augmented through the use of photodynamic therapy (PDT). Studies have shown a prolonged survival for the combinations of PDT and different stent applications as well as combinations of PDT and additional systemic chemotherapy. Conclusion More well-designed studies are needed to better evaluate and standardize endoscopic treatment of unresectable CCA. PMID:28229075

Endoscopic and Photodynamic Therapy of Cholangiocarcinoma.

PubMed

Meier, Benjamin; Caca, Karel

2016-12-01

Most patients with cholangiocarcinoma (CCA) have unresectable disease. Endoscopic bile duct drainage is one of the major objectives of palliation of obstructive jaundice. Stent implantation using endoscopic retrograde cholangiography is considered to be the standard technique. Unilateral versus bilateral stenting is associated with different advantages and disadvantages; however, a standard approach is still not defined. As there are various kinds of stents, there is an ongoing discussion on which stent to use in which situation. Palliation of obstructive jaundice can be augmented through the use of photodynamic therapy (PDT). Studies have shown a prolonged survival for the combinations of PDT and different stent applications as well as combinations of PDT and additional systemic chemotherapy. More well-designed studies are needed to better evaluate and standardize endoscopic treatment of unresectable CCA.

Fabrication of hydrophobic structures on coronary stent surface based on direct three-beam laser interference lithography

NASA Astrophysics Data System (ADS)

Gao, Long-yue; Zhou, Wei-qi; Wang, Yuan-bo; Wang, Si-qi; Bai, Chong; Li, Shi-ming; Liu, Bin; Wang, Jun-nan; Cui, Cheng-kun; Li, Yong-liang

2016-05-01

To solve the problems with coronary stent implantation, coronary artery stent surface was directly modified by three-beam laser interference lithography through imitating the water-repellent surface of lotus leaf, and uniform micro-nano structures with the controllable period were fabricated. The morphological properties and contact angle (CA) of the microstructure were measured by scanning electron microscope (SEM) and CA system. The water repellency of stent was also evaluated by the contact and then separation between the water drop and the stent. The results show that the close-packed concave structure with the period of about 12 μm can be fabricated on the stent surface with special parameters (incident angle of 3°, laser energy density of 2.2 J·cm-2 and exposure time of 80 s) by using the three-beam laser at 1 064 nm, and the structure has good water repellency with CA of 120°.

The interactions between bloodstream and vascular structure on aortic dissecting aneurysmal model: A numerical study

NASA Astrophysics Data System (ADS)

Chen, Zeng-Sheng; Fan, Zhan-Ming; Zhang, Xi-Wen

2013-06-01

Stent-graft implantation is an important means of clinical treatment for aortic dissecting aneurysm (ADA). However, researches on fluid dynamics effects of stent were rare. Computer simulation was used to investigate the interactions between bloodstream and vascular structure in a stented ADA, which endures the periodic pulse velocity and pressure. We obtained and analyzed the flow velocity distribution, the wall displacement and wall stress in the ADA. By comparing the different results between a non-stented and a stented ADA, we found that the insertion of a vascular graft can make the location of maximum stress and displacement move from the aneurysm lumen wall to the artery wall, accompanied with a greatly decrease in value. These results imply that the placement of a stent-graft of any kind to occlude ADA will result in a decreased chance of rupture.

Fabrication of Small Caliber Stent-grafts Using Electrospinning and Balloon Expandable Bare Metal Stents

PubMed Central

Uthamaraj, Susheil; Tefft, Brandon J.; Jana, Soumen; Hlinomaz, Ota; Kalra, Manju; Lerman, Amir; Dragomir-Daescu, Dan; Sandhu, Gurpreet S.

2016-01-01

Stent-grafts are widely used for the treatment of various conditions such as aortic lesions, aneurysms, emboli due to coronary intervention procedures and perforations in vasculature. Such stent-grafts are manufactured by covering a stent with a polymer membrane. An ideal stent-graft should have a biocompatible stent covered by a porous, thromboresistant, and biocompatible polymer membrane which mimics the extracellular matrix thereby promoting injury site healing. The goal of this protocol is to manufacture a small caliber stent-graft by encapsulating a balloon expandable stent within two layers of electrospun polyurethane nanofibers. Electrospinning of polyurethane has been shown to assist in healing by mimicking native extracellular matrix, thereby promoting endothelialization. Electrospinning polyurethane nanofibers on a slowly rotating mandrel enabled us to precisely control the thickness of the nanofibrous membrane, which is essential to achieve a small caliber balloon expandable stent-graft. Mechanical validation by crimping and expansion of the stent-graft has shown that the nanofibrous polyurethane membrane is sufficiently flexible to crimp and expand while staying patent without showing any signs of tearing or delamination. Furthermore, stent-grafts fabricated using the methods described here are capable of being implanted using a coronary intervention procedure using standard size guide catheters. PMID:27805589

Prospective, unmasked evaluation of the iStent® inject system for open-angle glaucoma: synergy trial.

PubMed

Voskanyan, Lilit; García-Feijoó, Julián; Belda, Jose I; Fea, Antonio; Jünemann, Anselm; Baudouin, Christophe

2014-02-01

Micro-invasive glaucoma surgical implantation of trabecular micro-bypass stents, previously shown to be safe and effective for open-angle glaucoma (OAG) subjects during cataract surgery, was considered for evaluation as a sole procedure. The aim of this study was to evaluate the safety and intraocular pressure (IOP)-lowering efficacy after ab interno implantation of two Glaukos Trabecular Micro-Bypass iStent inject second generation devices in subjects with OAG. This study was performed at sites in France, Germany, Italy, Republic of Armenia, and Spain. In this pan-European, multi-center prospective, post-market, unmasked study, 99 patients with OAG on at least two topical ocular hypotensive medications who required additional IOP lowering to control glaucoma disease underwent implantation of two GTS400 stents in a stand-alone procedure. Patients were qualified if they presented with preoperative mean IOP between 22 and 38 mmHg after medication washout. Postoperatively, subjects were assessed at Day 1, Months 1, 3, 6, 7, 9, and 12. IOP, medication use and safety were assessed at each visit. Sixty-six percent of subjects achieved IOP ≤18 mmHg at 12 months without medication, and 81% of subjects achieved Month 12 IOP ≤ 18 mmHg with either a single medication or no medication. Mean baseline washout IOP values decreased by 10.2 mmHg or 39.7% from 26.3 (SD 3.5) mmHg to 15.7 (SD 3.7) mmHg at Month 12. Mean IOP at 12 months was 14.7 (SD 3.1) mmHg in subjects not using ocular hypotensive medications. Reduction from preoperative medication burden was achieved in 86.9% of patients, including 15.2% with reduction of one medication and 71.7% with reduction of two or more medications. Postoperative complications occurred at a low rate and resolved without persistent effects. In this series, implantation of two trabecular micro-bypass second generation stents in subjects with OAG resulted in IOP and medication reduction and favorable safety outcomes.

IVUS Findings in Late and Very Late Stent Thrombosis. A Comparison Between Bare-metal and Drug-eluting Stents.

PubMed

Fuentes, Lara; Gómez-Lara, Josep; Salvatella, Neus; Gonzalo, Nieves; Hernández-Hernández, Felipe; Fernández-Nofrerias, Eduard; Sánchez-Recalde, Ángel; Alfonso, Fernando; Romaguera, Rafael; Ferreiro, José Luis; Roura, Gerard; Teruel, Luis; Gracida, Montserrat; Marcano, Ana Lucrecia; Gómez-Hospital, Joan-Antoni; Cequier, Ángel

2018-05-01

Stent thrombosis (ST) is a life-threatening complication after stent implantation. Intravascular ultrasound is able to discern most causes of ST. The aim of this study was to compare intravascular ultrasound findings between bare-metal stents (BMS) and drug-eluting stents (DES) in patients with late (31 days to 1 year) or very late ST (> 1 year). Of 250 consecutive patients with late or very late ST in 7 Spanish institutions, 114 patients (45.5% BMS and 54.5% DES) were imaged with intravascular ultrasound. Off-line intravascular ultrasound analysis was performed to assess malapposition, underexpansion, and neoatherosclerosis. The median time from stent implantation to ST was 4.0 years with BMS and 3.4 years with DES (P = .04). Isolated malapposition was similarly observed in both groups (36.5% vs 46.8%; P = .18) but was numerically lower with BMS (26.6% vs 48.0%; P = .07) in patients with very late ST. Isolated underexpansion was similarly observed in both groups (13.5% vs 11.3%; P = .47). Isolated neoatherosclerosis occurred only in patients with very late ST and was more prevalent with BMS (22.9%) than with DES (6.0%); P = .02. At 2.9 years' follow-up, there were 0% and 6.9% cardiac deaths, respectively (P = .06) and recurrent ST occurred in 4.0% and 5.2% of patients, respectively (P = .60). Malapposition was the most common finding in patients with late and very late ST and is more prevalent with DES in very late ST. In contrast, neoatherosclerosis was exclusively observed in patients with very late ST and mainly with BMS. Copyright © 2017 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

Effective treatment of benign biliary strictures with a removable, fully covered, self-expandable metal stent: A prospective, multicenter European study

PubMed Central

Schmidt, Arthur; Pickartz, Tilman; Lerch, Markus M; Fanelli, Fabrizio; Fiocca, Fausto; Lucatelli, Pierleone; Cereatti, Fabrizio; Hoffmeister, Albrecht; van Steenbergen, Werner; Kraft, Matthias; Meier, Benjamin

2016-01-01

Background Temporary placement of removable, fully covered, self-expandable metal stents (fcSEMS) for treatment of benign biliary strictures (BBS) has been reported to be effective. However, the optimal extraction time point remains unclear and stent migration has been a major concern. Objective The objective of this study was to evaluate the efficacy and safety of this treatment modality using an fcSEMS with a special antimigration design and prolonged stent indwell time. Methods We performed a prospective, single-arm study at six tertiary care centers in Europe. Patients with BBS underwent endoscopic or percutaneous implantation of an fcSEMS (GORE® VIABIL® Biliary Endoprosthesis, W.L. Gore & Associates, Flagstaff, AZ, USA). The devices were scheduled to be removed nine months later, and patients were to return for follow-up for an additional 15 months. Results Forty-three patients were enrolled in the study. Stricture etiology was chronic pancreatitis in the majority of patients (57.5%). All fcSEMS were placed successfully, either endoscopically (76.7%) or percutaneously (23.3%). Stent migration was observed in two patients (5.2%). Primary patency of the SEMS prior to removal was 73.0%. All attempted stent removals were successful. At removal, stricture was resolved or significantly improved without need for further therapy in 78.9% of patients. Stricture recurrence during a follow-up of two years post-implant was observed in two patients. Conclusions Temporary placement of the fcSEMS is a feasible, safe and effective treatment for BBS. The design of the device used in this study accounts for very low migration rates and facilitates easy stent retrieval, even after it has been in place for up to 11 months. PMID:28507752

Type D personality predicts death or myocardial infarction after bare metal stent or sirolimus-eluting stent implantation: a Rapamycin-Eluting Stent Evaluated at Rotterdam Cardiology Hospital (RESEARCH) registry substudy.

PubMed

Pedersen, Susanne S; Lemos, Pedro A; van Vooren, Priya R; Liu, Tommy K K; Daemen, Joost; Erdman, Ruud A M; Smits, Pieter C; Serruys, Patrick W J C; van Domburg, Ron T

2004-09-01

We investigated the effect of Type D personality on the occurrence of adverse events at nine months in patients with ischemic heart disease (IHD) after percutaneous coronary intervention (PCI) with sirolimus-eluting stents (SESs) or bare stents. Type D patients experience increased negative emotions and tend not to express these emotions in social interactions. The SES is a new advent in interventional cardiology that reduces the restenosis rate and the risk of a major adverse cardiac event, but the SES has not been shown to confer any benefits on death or myocardial infarction (MI). Consecutive patients with IHD (n = 875) enrolled in the Rapamycin-Eluting Stent Evaluated At Rotterdam Cardiology Hospital (RESEARCH) registry completed the Type D Personality Scale (DS14) six months after PCI. The end point was a composite of death and MI. Events occurring before administration of the DS14 were excluded from analyses. At nine months' follow-up, there were 20 events. Type D patients were at a cumulative increased risk of adverse outcome compared with non-Type D patients: 5.6% versus 1.3% (p < 0.002). Type D personality (odds ratio [OR] 5.31; 95% confidence interval [CI] 2.06 to 13.66) remained an independent predictor of adverse outcome adjusting for all other variables, including SES versus bare-stent implantation. Type D personality was an independent predictor of adverse events in patients optimally treated with the latest advent in interventional cardiology. The DS14 could be used as a screening instrument in routine clinical practice to optimize risk stratification in IHD patients.

Effective treatment of benign biliary strictures with a removable, fully covered, self-expandable metal stent: A prospective, multicenter European study.

PubMed

Schmidt, Arthur; Pickartz, Tilman; Lerch, Markus M; Fanelli, Fabrizio; Fiocca, Fausto; Lucatelli, Pierleone; Cereatti, Fabrizio; Hoffmeister, Albrecht; van Steenbergen, Werner; Kraft, Matthias; Meier, Benjamin; Caca, Karel

2017-04-01

Temporary placement of removable, fully covered, self-expandable metal stents (fcSEMS) for treatment of benign biliary strictures (BBS) has been reported to be effective. However, the optimal extraction time point remains unclear and stent migration has been a major concern. The objective of this study was to evaluate the efficacy and safety of this treatment modality using an fcSEMS with a special antimigration design and prolonged stent indwell time. We performed a prospective, single-arm study at six tertiary care centers in Europe. Patients with BBS underwent endoscopic or percutaneous implantation of an fcSEMS (GORE® VIABIL® Biliary Endoprosthesis, W.L. Gore & Associates, Flagstaff, AZ, USA). The devices were scheduled to be removed nine months later, and patients were to return for follow-up for an additional 15 months. Forty-three patients were enrolled in the study. Stricture etiology was chronic pancreatitis in the majority of patients (57.5%). All fcSEMS were placed successfully, either endoscopically (76.7%) or percutaneously (23.3%). Stent migration was observed in two patients (5.2%). Primary patency of the SEMS prior to removal was 73.0%. All attempted stent removals were successful. At removal, stricture was resolved or significantly improved without need for further therapy in 78.9% of patients. Stricture recurrence during a follow-up of two years post-implant was observed in two patients. Temporary placement of the fcSEMS is a feasible, safe and effective treatment for BBS. The design of the device used in this study accounts for very low migration rates and facilitates easy stent retrieval, even after it has been in place for up to 11 months.

A review on fracture prevention of stent in femoropopliteal artery

NASA Astrophysics Data System (ADS)

Atan, Bainun Akmal Mohd; Ismail, Al Emran; Taib, Ishkrizat; Lazim, Zulfaqih

2017-01-01

Heavily calcific lesions, total occlusions, tortuous blood vessels, variable lengths of arteries, various dynamic loads and deformations in the femoropopliteal (FP) arterial segment make stenosis treatments are complicated. The dynamic forces in FP artery including bending, torsion and radial compression may lead to stent fracture (SF) and eventually to in-stent restenosis (ISR). Stent design specifically geometrical configurations are a major factor need to be improved to optimize stent expansion and flexibility both bending and torsion during stent deployment into the diseased FP artery. Previous studies discovered the influence of various stent geometrical designs resulted different structural behaviour. Optimizing stent design can improve stent performances: flexibility and radial strength to prevent SF in FP arterial segment

Silver-nanoparticle-coated biliary stent inhibits bacterial adhesion in bacterial cholangitis in swine.

PubMed

Wen, Wei; Ma, Li-Mei; He, Wei; Tang, Xiao-Wei; Zhang, Yin; Wang, Xiang; Liu, Li; Fan, Zhi-Ning

2016-02-01

One of the major limitations of biliary stents is the stent occlusion, which is closely related to the over-growth of bacteria. This study aimed to evaluate the feasibility of a novel silver-nanoparticle-coated polyurethane (Ag/PU) stent in bacterial cholangitis model in swine. Ag/PU was designed by coating silver nanoparticles on polyurethane (PU) stent. Twenty-four healthy pigs with bacterial cholangitis using Ag/PU and PU stents were randomly divided into an Ag/PU stent group (n=12) and a PU stent group (n=12), respectively. The stents were inserted by standard endoscopic retrograde cholangiopancreatography. Laboratory assay was performed for white blood cell (WBC) count, alanine aminotransferase (ALT), interleukin-1beta (IL-1beta), tumor necrosis factor-alpha (TNF-alpha) at baseline time, 8 hours, 1, 2, 3, and 7 days after stent placements. The segment of bile duct containing the stent was examined histologically ex vivo. Implanted biliary stents were examined by a scan electron microscope. The amount of silver release was also measured in vitro. The number of inflammatory cells and level of ALT, IL-1beta and TNF-alpha were significantly lower in the Ag/PU stent group than in the PU stent group. Hyperplasia of the mucosa was more severe in the PU stent group than in the Ag/PU stent group. In contrast to the biofilm of bacteria on the PU stent, fewer bacteria adhered to the Ag/PU stent. PU biliary stents modified with silver nanoparticles are able to alleviate the inflammation of pigs with bacterial cholangitis. Silver-nanoparticle-coated stents are resistant to bacterial adhesion.

Safety Outcomes Using a Proximal Protection Device in Carotid Stenting of Long Carotid Stenoses

PubMed Central

Atchaneeyasakul, Kunakorn; Khandelwal, Priyank; Ambekar, Sudheer; Ramdas, Kevin; Guada, Luis; Yavagal, Dileep

2016-01-01

Background Embolic protection devices can prevent atherosclerotic emboli during carotid stenting. Newer proximal protection devices reverse flow in the internal carotid artery (ICA), leading to reduction in perioperative microemboli. The risk of stroke is high for carotid stenting of ICA lesions with a length >10 mm and/or angiographic string sign. Objective We aimed to evaluate the safety outcomes of proximal embolic protection device usage in this high-risk group. Methods This is a retrospective analysis of patients who underwent carotid stenting procedures with proximal embolic protection devices at a tertiary care center. High-risk features for adverse events with carotid stenting were identified. Peri- and postprocedural outcomes were recorded. We further compared outcomes in patients with a carotid stenosis length >10 mm to those with shorter stenosis. Results From January 2011 to December 2014, we included 27 patients; 96.3% were symptomatic and 3.7% were asymptomatic. There was a stent placement technical success rate of 100%. No major stroke or coronary events were recorded. One minor stroke event developed in one patient. A carotid lesion length >10 mm and/or angiographic string sign was noted in 21/27 patients, with an average lesion length of 14.4 mm. One patient (4.8%) in this group developed a minor stroke event. Neither a coronary nor a major stroke event was recorded in this group. There was no significant difference in the complication rate between the long lesion and the control group. Conclusion In our patient cohort, it was found that a proximal embolic protection device is safe for patients with carotid stenosis, including those with a carotid lesion length >10 mm and/or angiographic string sign. PMID:27781040

Customized Hinged Covered Metallic Stents for the Treatment of Benign Main Bronchial Stenosis.

PubMed

Han, Xinwei; Al-Tariq, Quazi; Zhao, Yanle; Li, Lei; Cheng, Zhe; Wang, Huaqi; Liu, Chao; Jiao, Dechao; Wu, Gang

2017-08-01

To address the limitations of silicone stents, we designed a hinged self-expandable covered metallic stent. The aim of this study was to evaluate the safety and efficacy of the customized stents in clinical applications. This was a retrospective analysis. Under conscious sedation and local anesthesia, the stents were implanted or removed by interventional radiologists, with fluoroscopic guidance. Of 24 patients with benign main bronchial stenosis, stents were successfully placed in 21 (87.5%). The low-pressure balloon before dilation failed in 1 case (4.17%) of left main bronchial cicatricial stenosis. In 2 other cases (8.33%), stent placement was abandoned. Stents were successfully removed between 29 and 103 days after the procedure. After stent removal, the follow-up lasted for at least 12 months. Restenosis occurred only in 1 case (4.55%) owing to bronchial collapse 3 days after stent removal. Dyspnea occurred in another case (4.55%) at 2 months after retrieval; recurrence was confirmed using bronchoscopy, leading to a left pneumonectomy. The described procedure is safe and easy to be performed and avoids the use of intubation, bronchoscopy, and general anesthesia. Copyright © 2017 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Morphology characterization and biocompatibility study of PLLA (Poly-L-Llactid-Acid) coating chitosan as stent for coronary heart disease

NASA Astrophysics Data System (ADS)

Widiyanti, Prihartini; Paramadini, Adanti W.; Jabbar, Hajria; Fatimah, Inas; Nisak, Fadila N. K.; Puspitasari, Rahma A.

2016-03-01

Cardiovascular disease is a global disease with high urgency. In the severe case of coronary heart disease while a blockage in the coronary arteries reach 75% or more, the patient required stent implantation. Stents are made of metal which has many limitations that can lead to blood clots and stent incompatibility toward the size of the blood vessels. There is a metal stent replacement solution that made from polymer material which is biocompatible. PLLA also has biocompatibility and good mechanical strength. PLLA stent will be coated with chitosan as a candidate for drug-coated stents which is able to work as a drug carrier. The aim of this study is to know the morphology information and biocompability status of PLLA coating chitosan as candidate of heart stent. Morphological results using SEM showed a smooth surface structure which reinforced clinical standard of stent material. Results of cytotoxicity test by MTT Assay method showed that the result of four samples in this experiment living cells is reached 90% which is non toxic and safe to use in the human body. %). The conclusion of this study is PLLA is polymer has potency to be used as stent material.

Recent perspective on coronary artery bifurcation interventions.

PubMed

Dash, Debabrata

2014-01-01

Coronary bifurcation lesions are frequent in routine practice, accounting for 15-20% of all lesions undergoing percutaneous coronary intervention (PCI). PCI of this subset of lesions is technically challenging and historically has been associated with lower procedural success rates and worse clinical outcomes compared with non-bifurcation lesions. The introduction of drug-eluting stents has dramatically improved the outcomes. The provisional technique of implanting one stent in the main branch remains the default approach in most bifurcation lesions. Selection of the most effective technique for an individual bifurcation is important. The use of two-stent techniques as an intention to treat is an acceptable approach in some bifurcation lesions. However, a large amount of metal is generally left unapposed in the lumen with complex two-stent techniques, which is particularly concerning for the risk of stent thrombosis. New technology and dedicated bifurcation stents may overcome some of the limitations of two-stent techniques and revolutionise the management of bifurcation PCI in the future.

Use of the Viatorr Expanded Polytetrafluoroethylene-Covered Stent-Graft for Transjugular Intrahepatic Portosystemic Shunt Creation in Children: Initial Clinical Experience

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mermuys, Koen; Maleux, Geert, E-mail: geert.maleux@uzleuven.be; Heye, Sam

2008-07-15

Four children, three boys and one girl, with a median age of 9 years 8 months, underwent transjugular intrahepatic portosystemic shunt creation with an expanded polytetrafluoroethylene (e-PTFE)-covered nitinol stent. The stent-graft was successfully placed in all four patients without any complication. Clinical and biochemical improvement was noted in all four patients during follow-up. Radiological follow-up with use of duplex ultrasound showed a recurrent stenosis of the shunt 180 days after stent-graft implantation in one patient. This was treated with placement of an additional stent-graft, re-expanding completely the recurrent stenosis. In the other three patients, the stent-graft remained fully patent untilmore » the end of the study or until orthotopic liver transplantation. These preliminary results suggest that use of the Viatorr ePTFE-covered stent-graft in children is safe and feasible, with potentially the same high patency rate and improved clinical outcome as reported in adult patients.« less

Treatment of a coronary artery aneurysm by use of a covered stent graft – a case report

PubMed Central

Gundoğdu, Fuat; Arslan, Sakir; Buyukkaya, Eyup; Senocak, Huseyin

2007-01-01

Coronary artery aneurysm is a rare finding at coronary angiography. Most coronary aneurysms remain asymptomatic. There is no consensus on its management; some advocate aggressive approach while others advocate conservative management. A case of coronary artery aneurysm successfully treated by implantation of a polytetrafluoroethylene-covered coronary stent is presented. PMID:22477247

[Evaluation of Radiation Dose during Stent-graft Treatment Using a Hybrid Operating Room System].

PubMed

Haga, Yoshihiro; Chida, Kouichi; Kaga, Yuji; Saitou, Kazuhisa; Arai, Takeshi; Suzuki, Shinichi; Iwaya, Yoshimi; Kumasaka, Eriko; Kataoka, Nozomi; Satou, Naoto; Abe, Mitsuya

2015-12-01

In recent years, aortic aneurysm treatment with stent graft grafting in the X-ray fluoroscopy is increasing. This is an endovascular therapy, because it is a treatment which includes the risk of radiation damage, having to deal with radiation damage, to know in advance is important. In this study, in order to grasp the trend of exposure stent graft implantation in a hybrid operating room (OR) system, focusing on clinical data (entrance skin dose and fluoroscopy time), was to count the total. In TEVAR and EVAR, fluoroscopy time became 13.40 ± 7.27 minutes, 23.67 ± 11.76 minutes, ESD became 0.87 ± 0.41 mGy, 1.11 ± 0.57 mGy. (fluoroscopy time of EVAR was 2.0 times than TEVAR. DAP of EVAR was 1.2 times than TEVAR.) When using the device, adapted lesions and usage are different. This means that care changes in exposure-related factors. In this study, exposure trends of the stent graft implantation was able to grasp. It can be a helpful way to reduce/optimize the radiation dose in a hybrid OR system.

Efficacy of different types of self-expandable stents in carotid artery stenting for carotid bifurcation stenosis.

PubMed

Liu, Ya-min; Qin, Hao; Zhang, Bo; Wang, Yu-jing; Feng, Jun; Wu, Xiang

2016-02-01

Both open and closed loop self-expandable stents were used in carotid artery stenting (CAS) for carotid bifurcation stenosis. We sought to compare the efficacy of two types of stents in CAS. The data of 212 patients treated with CAS (42 and 170 cases implanted with closed and open loop stents, respectively) for carotid bifurcation stenosis and distal filtration protection devices were retrospectively analyzed. Between closed and open loop stents, there were no significant differences in hospitalization duration, NIHSS score before and after the treatment, stenosis at 12th month, and cumulative incidence of primary endpoint events within 30 days or from the 31st day to the 12th month; while there were significant differences in hemodynamic changes and rate of difficulty in recycling distal filtration protection devices. Use of open vs. closed loop stents for carotid bifurcation stenosis seems to be associated with similar incidence of complications, except for greater rate of hemodynamic changes and lower rate of difficulty in recycling the distal filtration protection devices.

Clinical outcomes and stent thrombosis following off-label use of drug-eluting stents.

PubMed

Win, Htut K; Caldera, Angel E; Maresh, Kelly; Lopez, John; Rihal, Charanjit S; Parikh, Manish A; Granada, Juan F; Marulkar, Sachin; Nassif, Deborah; Cohen, David J; Kleiman, Neal S

2007-05-09

Clinical trials that have excluded patients at high risk for cardiac events have led to commercial labeling approval of drug-eluting stents; nevertheless, such high-risk patients commonly undergo stent placement in clinical practice. The degree to which they experience cardiac events at a higher rate than non-high-risk patients is unclear. To assess the rates of major adverse cardiac events during the index admission and 1 year after the implantation of drug-eluting stents in patients with high-risk angiographic and clinical features. From July 2004 to September 2005, consecutive patients who underwent attempted stent placement at 42 different hospitals throughout the United States were enrolled in a prospective multicenter registry. We analyzed outcomes of 3323 patients who received at least 1 drug-eluting stent for a reason other than acute ST-segment elevation myocardial infarction. The study population was divided into 2 groups based on presence of at least 1 of 9 off-label characteristics based on the current US Food and Drug Administration-approved indications for sirolimus- and paclitaxel-eluting stents. The composite clinical outcomes of death, myocardial infarction, or target vessel revascularization during the index admission and death, myocardial infarction, or target lesion revascularization at 1 year were evaluated. Of the 3323 patients, 1817 (54.7%) had at least 1 off-label characteristic. During the index hospitalization, the composite clinical outcome occurred in 198 (10.9%) of patients in the off-label group and 76 (5.0%) of patients in the on-label group (adjusted odds ratio, 2.32; 95% confidence interval [CI], 1.75-3.07; P<.001). At 1 year, the composite clinical outcome occurred more often in the off-label group compared with the on-label group; 309 (17.5%) vs 131 (8.9%) (adjusted hazard ratio [HR], 2.16; 95% CI, 1.74-2.67; P<.001). Stent thrombosis also occurred more frequently among patients in the off-label group during the initial hospitalization (8 [0.4%] vs 0) and at 1 year: 29 (1.6%) vs 13 (0.9%), adjusted HR, 2.29 (95% CI, 1.02-5.16; P = .05). Compared with on-label use, off-label use of drug-eluting stents is associated with a higher rate of adverse outcomes during the index admission and at 1 year. Stent thrombosis occurred predominantly in patients who underwent off-label drug-eluting stent implantation. Clinicians should be cautious about extrapolating the benefits of drug-eluting stents over bare-metal stents observed in randomized clinical trials to higher-risk clinical settings that have not been assessed.

The Suprachoroidal Route in Glaucoma Surgery

PubMed Central

Shaarawy, Tarek

2016-01-01

ABSTRACT Glaucoma surgeries targeting the uveoscleral drainage pathways have been drawing more attention lately. Among all the available techniques, procedures focusing on the supra-choroidal space seem particularly promising, by making use of a presumably efficient and secure outflow route and avoiding subconjunctival filtration blebs. The purpose of this review is to assess the efficacy and the security of the different suprachoroidal drainage implants, namely the CyPass Micro-Stent, the iStent Supra, the SOLX Gold Shunt, the Aquashunt, and the STARflo Glaucoma Implant. Most clinical studies seem to currently point toward the direction that there are actual benefits in suprachoroidal surgeries by avoiding bleb-related complications. Nevertheless, even suprachoroidal implants may be subject to scarring and failure. More data are still needed, especially concerning long-term effects, although the approach does seem appealing. How to cite this article: Gigon A, Shaarawy T. The Suprachoroidal Route in Glaucoma Surgery. J Curr Glaucoma Pract 2016;10(1): 13-20. PMID:27231415

Current evidence for the safety and efficacy of the bio-engineered dual therapy COMBO stent.

PubMed

Kalkman, Deborah N; Chandrasekhar, Jaya; de Winter, Robbert J; Mehran, Roxana

2018-06-01

The novel dual-therapy COMBO stent aims to promote vessel healing after percutaneous coronary intervention (PCI) in patients with coronary artery disease. The pro-healing technique consists of an anti-CD34+ antibody layer that attracts circulating endothelial progenitor cells (EPCs), which bind to the stent surface and allow rapid endothelialization by differentiation of the EPCs into normal endothelial cells. The COMBO stent combines this pro-healing technique with an abluminal drug elution of sirolimus. The promise of this dual-therapy stent is that it may safely allow a shortened duration of dual-antiplatelet therapy (DAPT) after stent placement. Moreover, with a mature endothelial layer, lower rates of in-stent restenosis may be expected. Clinical outcomes after COMBO stent implantation have been recently evaluated in both randomized trials and large, prospective, multicenter registries, showing low clinical event rates of in-stent restenosis and stent thrombosis. Randomized clinical trials (HARMONEE and RECOVERY) have demonstrated the non-inferiority of COMBO versus "first in class" second generation and newer generation drug-eluting stents. Safety and efficacy of 3 months of DAPT after COMBO stent placement in patients presenting with acute coronary syndrome has been evaluated in the large REDUCE randomized controlled trial, showing non-inferiority to standard duration of 12-month DAPT. In this review we provide an overview of the current pre-clinical and clinical evidence for the performance of the COMBO stent.

Particle imaging velocimetry evaluation of intracranial stents in sidewall aneurysm: hemodynamic transition related to the stent design.

PubMed

Bouillot, Pierre; Brina, Olivier; Ouared, Rafik; Lovblad, Karl-Olof; Farhat, Mohamed; Pereira, Vitor Mendes

2014-01-01

We investigated the flow modifications induced by a large panel of commercial-off-the-shelf (COTS) intracranial stents in an idealized sidewall intracranial aneurysm (IA). Flow velocities in IA silicone model were assessed with and without stent implantation using particle imaging velocimetry (PIV). The use of the recently developed multi-time-lag method has allowed for uniform and precise measurements of both high and low velocities at IA neck and dome, respectively. Flow modification analysis of both regular (RSs) and flow diverter stents (FDSs) was subsequently correlated with relevant geometrical stent parameters. Flow reduction was found to be highly sensitive to stent porosity variations for regular stents RSs and moderately sensitive for FDSs. Consequently, two distinct IA flow change trends, with velocity reductions up to 50% and 90%, were identified for high-porosity RS and low-porosity FDS, respectively. The intermediate porosity (88%) regular braided stent provided the limit at which the transition in flow change trend occurred with a flow reduction of 84%. This transition occurred with decreasing stent porosity, as the driving force in IA neck changed from shear stress to differential pressure. Therefore, these results suggest that stents with intermediate porosities could possibly provide similar flow change patterns to FDS, favourable to curative thrombogenesis in IAs.

External heating of stents by radio waves Pilot studies in rabbit aorta

DOE Office of Scientific and Technical Information (OSTI.GOV)

Levitt, Adam B.; Robinson, Keith; Chronos, Nicolas A.F.

Purpose: This experiment was designed to assess the feasibility of radio frequency energy delivered by a prototype radio frequency generator inductive heating device (REVAX) positioned external to the body, for transient heating of stents after arterial implant. Methods and Materials: Twenty-one New Zealand White rabbits underwent stenting of their infrarenal aorta. Nine rabbits were stented and immediately placed in the REVAX for external stent heating with internal temperature probes in place. Twelve rabbits were stented and 3 days later either heated or placed in the generator as a sham for 20 min. The animals were terminated 28 days later. Results:more » The REVAX was able to heat the aortic stents in a controlled fashion; in Phase II experiments, the stent temperature was raised to 42 deg. C for 20 min. In Phase I mild necrosis was noted at the stent struts. In Phase II, necrosis and mineralization of the media was seen at the stent struts, and evidence of neointimal suppression was observed. Conclusion: This study demonstrated that external heating of stents in a blood vessel in a live animal via radio frequency energy is feasible. Further studies will be needed to assess whether any specific heating regimen might inhibit fibrocellular neointimal hyperplasia.« less

Influence of strut cross-section of stents on local hemodynamics in stented arteries

NASA Astrophysics Data System (ADS)

Jiang, Yongfei; Zhang, Jun; Zhao, Wanhua

2016-05-01

Stenting is a very effective treatment for stenotic vascular diseases, but vascular geometries altered by stent implantation may lead to flow disturbances which play an important role in the initiation and progression of restenosis, especially in the near wall in stented arterial regions. So stent designs have become one of the indispensable factors needed to be considered for reducing the flow disturbances. In this paper, the structural designs of strut cross-section are considered as an aspect of stent designs to be studied in details. Six virtual stents with different strut cross-section are designed for deployments in the same ideal arterial model. Computational fluid dynamics (CFD) methods are performed to study how the shape and the aspect ratio (AR) of strut cross-section modified the local hemodynamics in the stented segments. The results indicate that stents with different strut cross-sections have different influence on the hemodynamics. Stents with streamlined cross-sectional struts for circular arc or elliptical arc can significantly enhance wall shear stress (WSS) in the stented segments, and reduce the flow disturbances around stent struts. The performances of stents with streamlined cross-sectional struts are better than that of stents with non-streamlined cross-sectional struts for rectangle. The results also show that stents with a larger AR cross-section are more conductive to improve the blood flow. The present study provides an understanding of the flow physics in the vicinity of stent struts and indicates that the shape and AR of strut cross-section ought to be considered as important factors to minimize flow disturbance in stent designs.

Structural Mechanics Predictions Relating to Clinical Coronary Stent Fracture in a 5 Year Period in FDA MAUDE Database

PubMed Central

Everett, Kay D.; Conway, Claire; Desany, Gerard J.; Baker, Brian L.; Choi, Gilwoo; Taylor, Charles A.; Edelman, Elazer R.

2016-01-01

Endovascular stents are the mainstay of interventional cardiovascular medicine. Technological advances have reduced biological and clinical complications but not mechanical failure. Stent strut fracture is increasingly recognized as of paramount clinical importance. Though consensus reigns that fractures can result from material fatigue, how fracture is induced and the mechanisms underlying its clinical sequelae remain ill-defined. In this study, strut fractures were identified in the prospectively maintained Food and Drug Administration's (FDA) Manufacturer and User Facility Device Experience Database (MAUDE), covering years 2006–2011, and differentiated based on specific coronary artery implantation site and device configuration. These data, and knowledge of the extent of dynamic arterial deformations obtained from patient CT images and published data, were used to define boundary conditions for 3D finite element models incorporating multimodal, multi-cycle deformation. The structural response for a range of stent designs and configurations was predicted by computational models and included estimation of maximum principal, minimum principal and equivalent plastic strains. Fatigue assessment was performed with Goodman diagrams and safe/unsafe regions defined for different stent designs. Von Mises stress and maximum principal strain increased with multimodal, fully reversed deformation. Spatial maps of unsafe locations corresponded to the identified locations of fracture in different coronary arteries in the clinical database. These findings, for the first time, provide insight into a potential link between patient adverse events and computational modeling of stent deformation. Understanding of the mechanical forces imposed under different implantation conditions may assist in rational design and optimal placement of these devices. PMID:26467552

Structural Mechanics Predictions Relating to Clinical Coronary Stent Fracture in a 5 Year Period in FDA MAUDE Database.

PubMed

Everett, Kay D; Conway, Claire; Desany, Gerard J; Baker, Brian L; Choi, Gilwoo; Taylor, Charles A; Edelman, Elazer R

2016-02-01

Endovascular stents are the mainstay of interventional cardiovascular medicine. Technological advances have reduced biological and clinical complications but not mechanical failure. Stent strut fracture is increasingly recognized as of paramount clinical importance. Though consensus reigns that fractures can result from material fatigue, how fracture is induced and the mechanisms underlying its clinical sequelae remain ill-defined. In this study, strut fractures were identified in the prospectively maintained Food and Drug Administration's (FDA) Manufacturer and User Facility Device Experience Database (MAUDE), covering years 2006-2011, and differentiated based on specific coronary artery implantation site and device configuration. These data, and knowledge of the extent of dynamic arterial deformations obtained from patient CT images and published data, were used to define boundary conditions for 3D finite element models incorporating multimodal, multi-cycle deformation. The structural response for a range of stent designs and configurations was predicted by computational models and included estimation of maximum principal, minimum principal and equivalent plastic strains. Fatigue assessment was performed with Goodman diagrams and safe/unsafe regions defined for different stent designs. Von Mises stress and maximum principal strain increased with multimodal, fully reversed deformation. Spatial maps of unsafe locations corresponded to the identified locations of fracture in different coronary arteries in the clinical database. These findings, for the first time, provide insight into a potential link between patient adverse events and computational modeling of stent deformation. Understanding of the mechanical forces imposed under different implantation conditions may assist in rational design and optimal placement of these devices.

Mechanical Characteristics of Composite Knitted Stents

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tokuda, Takanori, E-mail: tkdtknr@gmail.com; Shomura, Yuzo; Tanigawa, Noboru

2009-09-15

We used metal wires and fibers to fabricate a composite knitted stent and then compare the mechanical characteristics of this stent with those of a pure metallic stent of the same construction in order to develop a stent that offers a comparable degree of expandability as metallic stents but can be used for highly curved lesions that cannot be treated using metallic stents. We fabricated two types of composite knitted stent (N-Z stents), using nitinol wire with a diameter of 0.12 mm and polypara-phenylene-benzobisoxazole (PBO) multifilament fiber (Zyron AS; Toyobo, Osaka, Japan). Stents were knitted into a cylindrical shape usingmore » the same textile pattern as a Strecker stent. Two loop lengths (L) of nitinol wire were used in the N-Z stents: L = 1.84 mm (N-Z stent L = 1.84) and L = 2.08 mm (N-Z stent L = 2.08). For the sake of comparison, we fabricated a metallic stent of nitinol using the same textile pattern (N-N stent L = 1.92). We applied a radial compression force diametrically to each stent and applied a bending force diametrically at the free end of a stent with one end fixed in order to evaluate the relationship between stent elasticity and load values. In addition, we macroscopically evaluated the generation of kinks when the stent was bent 180{sup o}. The radial compressive force when the stent diameter was reduced by 53% was 6.44 N in the case of N-Z stent L = 1.84, 6.14 N in the case of N-Z stent L = 2.08, and 4.96 N in the case of N-N stent L = 1.92 mm. The composite stent had a radial compressive force higher than that of a metallic stent. The restoring force to longitudinal direction at a 90{sup o} bending angle was 0.005 N for N-Z stent L = 1.84, 0.003 N for N-Z stent L = 2.08, and 0.034 N for N-N stent L = 1.92. The restoring force of the composite stent was significantly lower. Finally, the composite stent generated no definitive kinks at a bending angle of 180{sup o}, regardless of loop length. However, the N-N stent clearly produced kinks, causing blockage of the inner cavity. In conclusion, the use of a metal and fiber composite in the construction of a knitted stent ensures an expansion performance comparable to that of metallic stents, while providing better kink resistance.« less

A newly designed big cup nitinol stent for gastric outlet obstruction

PubMed Central

Shi, Ding; Liao, Sheng-Hui; Geng, Jian-Ping

2010-01-01

AIM: To find out whether a newly designed big cup nitinol stent is suitable for treatment of patients with gastric outlet obstruction resulting from gastric cancer. METHODS: The new stent is composed of a proximal big cup segment (20 mm in length and 48-55 mm in diameter), a middle part (60 mm in length and 20 mm in diameter) covered by a polyethylene membrane and a distal sphericity (20 mm in length and 28 mm in diameter). Half of the proximal big cup segment is also covered by a polyethlene membrane, which is adjacent to the middle part of the stent. The stent is preloaded in a 6.0-mm-diameter introducer system. Thirteen patients with gastric outlet obstruction resulting from gastric cancer received the new stents under endoscopic and fluoroscopic guidance. RESULTS: Technical success was achieved in 12 of 13 (92.3%) patients. Among the 12 patients in whom endoscopic stent was placed successfully, the clinical success rate was 91.7% during a follow-up of average 6.5 mo. During the first month follow-up, the migration rate was 0%, recurrent obstruction 0% and gastric bleeding 8.3%. During the follow-up between 2-12 mo, no migration, recurrent obstruction and gastric bleeding occurred. CONCLUSION: The proximal big cup segment seems to be effective and promising for technical efficacy, clinical outcome, and preventing migration and tumor ingrowth and increasing the emptying rate of sinus ventriculi. PMID:20806440

Wall shear stress distributions on stented patent ductus arteriosus

NASA Astrophysics Data System (ADS)

Kori, Mohamad Ikhwan; Jamalruhanordin, Fara Lyana; Taib, Ishkrizat; Mohammed, Akmal Nizam; Abdullah, Mohammad Kamil; Ariffin, Ahmad Mubarak Tajul; Osman, Kahar

2017-04-01

A formation of thrombosis due to hemodynamic conditions after the implantation of stent in patent ductus arteriosus (PDA) will derived the development of re-stenosis. The phenomenon of thrombosis formation is significantly related to the distribution of wall shear stress (WSS) on the arterial wall. Thus, the aims of this study is to investigate the distribution of WSS on the arterial wall after the insertion of stent. Three dimensional model of patent ductus arteriosus inserted with different types of commercial stent are modelled. Computational modelling is used to calculate the distributions of WSS on the arterial stented PDA. The hemodynamic parameters such as high WSS and WSSlow are considered in this study. The result shows that the stented PDA with Type III stent has better hemodynamic performance as compared to others stent. This model has the lowest distributions of WSSlow and also the WSS value more than 20 dyne/cm2. From the observed, the stented PDA with stent Type II showed the highest distributions area of WSS more than 20 dyne/cm2. This situation revealed that the high possibility of atherosclerosis to be developed. However, the highest distribution of WSSlow for stented PDA with stent Type II indicated that high possibility of thrombosis to be formed. In conclusion, the stented PDA model calculated with the lowest distributions of WSSlow and WSS value more than 20dyne/cm2 are considered to be performed well in stent hemodynamic performance as compared to other stents.

A new polymer-free drug-eluting stent with nanocarriers eluting sirolimus from stent-plus-balloon compared with bare-metal stent and with biolimus A9 eluting stent in porcine coronary arteries

PubMed Central

Galon, Micheli Z.; Gutierrez, Paulo S.; Sojitra, Prakash; Vyas, Ashwin; Doshi, Manish; Lemos, Pedro A.

2015-01-01

Background Permanent polymers in first generation drug-eluting stent (DES) have been imputed to be a possible cause of persistent inflammation, remodeling, malapposition and late stent thrombosis. We aim to describe the in vivo experimental result of a new polymer-free DES eluting sirolimus from stent-plus-balloon (Focus np stent, Envision Scientific) compared with a bare-metal stent (BMS) (Amazonia CroCo, Minvasys) and with a biolimus A9 eluting stent (Biomatrix, Biosensors). Methods In 10 juvenile pigs, 23 coronary stents were implanted in the coronary arteries (8 Amazonia CroCo, 8 Focus np, and 7 Biomatrix). At 28-day follow-up, optical coherence tomography (OCT) and histology were used to evaluate neointimal hyperplasia and healing response. Results According to OCT analysis, Focus np stents had a greater lumen area and less neointimal hyperplasia response than BMS and Biomatrix had. Histomorphometry results showed less neointimal hyperplasia in Focus np than in BMS. Histology showed a higher fibrin deposition in Biomatrix stent compared to Focus np and BMS. Conclusions The new polymer-free DES with sirolimus eluted from stent-plus-balloon demonstrated safety and reduced neointimal proliferation compared with the BMS and Biomatrix stents at 28-day follow-up in this porcine coronary model. This new polymer-free DES is promising and warrants further clinical studies. PMID:25984451

Impact of Fluoropolymer-Based Paclitaxel Delivery on Neointimal Proliferation and Vascular Healing: A Comparative Peripheral Drug-Eluting Stent Study in the Familial Hypercholesterolemic Swine Model of Femoral Restenosis.

PubMed

Gasior, Pawel; Cheng, Yanping; Valencia, Andres F; McGregor, Jenn; Conditt, Gerard B; Kaluza, Grzegorz L; Granada, Juan F

2017-05-01

A polymer-free peripheral paclitaxel-eluting stent (PES, Zilver PTX, Cook, IN) has shown to improve vessel patency after superficial femoral angioplasty. A new-generation fluoropolymer-based PES (FP-PES; Eluvia, Boston Scientific, MA) displaying more controlled and sustained paclitaxel delivery promise to improve the clinical outcomes of first-generation PES. We sought to compare the biological effect of paclitaxel delivered by 2 different stent-coating technologies (fluoropolymer-based versus polymer-free) on neointimal proliferation and healing response in the familial hypercholesterolemic swine model of femoral restenosis. The biological efficacy of clinically available FP-PES (n=12) and PES (n=12) was compared against a bare metal stent control (n=12; Innova, Boston Scientific, MA) after implantation in the femoral arteries of 18 familial hypercholesterolemic swine. Longitudinal quantitative vascular angiography and optical coherence tomography were performed at baseline and at 30 and 90 days. Histological evaluation was performed at 90 days. Ninety-day quantitative vascular angiography results showed a lower percent diameter stenosis for FP-PES (38.78% [31.27-47.66]) compared with PES (54.16% [42.60-61.97]) and bare metal stent (74.52% [47.23-100.00]; P <0.001). Ninety-day optical coherence tomography results demonstrated significantly lower neointimal area in FP-PES (8.01 mm 2 [7.65-9.21]) compared with PES (10.95 mm 2 [9.64-12.46]) and bare metal stent (13.83 mm 2 [11.53-17.03]; P <0.001). Histological evaluation showed larger lumen areas and evidence of higher biological activity (smooth muscle cell loss and fibrin deposition) in the FP-PES compared with PES and bare metal stent. In the familial hypercholesterolemic swine model of femoral restenosis, the implantation of an FP-PES resulted in lower levels of neointimal proliferation and sustained biological effect ≤90 days compared with a polymer-free stent-based approach. © 2017 American Heart Association, Inc.

One Year Clinical Outcomes of Renal Artery Stenting: The Results of ODORI Registry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sapoval, M., E-mail: marc.sapoval2@egp.aphp.f; Tamari, I.; Goffette, P.

2010-06-15

The safety, efficacy and long term clinical benefits of renal artery revascularization by stenting are still a matter of debate. The aim of our study was to define the safety and efficacy of renal artery stenting with the Tsunami peripheral stent (Terumo Corporation, Tokyo, Japan). The ODORI was a prospective, multicentre registry which enrolled 251 consecutive patients, (276 renal arteries) in 36 centres across Europe. The primary endpoint was acute procedural success defined as <30% residual stenosis after stent placement. Secondary endpoints included major adverse events, blood pressure control, serum creatinine level, and target lesion revascularization (TLR) at 6 andmore » 12 months. Patients were 70 {+-} 10 years old, 59% were male, 33% had diabetes, and 96% hypertension. The main indications for renal stent implantation were hypertension in 83% and renal salvage in 39%. Direct stent implantation was performed in 76% of the cases. Acute success rate was 100% with residual stenosis of 2.5 {+-} 5.4%. Systolic/diastolic blood pressure decreased from a mean of 171/89 at baseline to 142/78 mmHg at 6 months (p < 0.0001 vs. baseline), and 141/80 mmHg at 12 months (p < 0.0001 vs. baseline). Mean serum creatinine concentration did not change significantly in the total population. However, there was significant improvement in the highest tercile (from 283 {mu}mol/l at baseline to 205 and 209 {mu}mol/l at 6 and 12 months respectively). At 12-months, rates of restenosis and TLR were 6.6 and 0.8% respectively. The 12 month cumulative rate of all major clinical adverse events was 6.4% while the rate of device or procedure related events was 2.4%. In hypertensive patients with atherosclerotic renal artery stenosis Tsunami peripheral balloon-expandable stent provides a safe revascularization strategy, with a potential beneficial impact on hypertension control and renal function in the highest risk patients.« less

Drug-eluting stents versus bare-metal stents for off-label indications: a propensity score-matched outcome study.

PubMed

Austin, David; Oldroyd, Keith G; McConnachie, Alex; Slack, Rachel; Eteiba, Hany; Flapan, Andrew D; Jennings, Kevin P; Northcote, Robin J; Pell, Alastair C H; Starkey, Ian R; Pell, Jill P

2008-08-01

The US Food and Drug Administration recently concluded that data on off-label drug-eluting stent (DES) safety are limited. However, in actual clinical practice, DES are often used for off-label indications, and observational studies demonstrate that complications are higher when compared with on-label use. We aimed to determine whether clinical outcomes differ after DES and bare-metal stent implantation in a patient cohort defined by DES off-label indications. We used the national revascularization registry in Scotland to identify patients who underwent coronary stenting for an off-label indication between January 2003 and September 2005. Individual-level linkage to comprehensive national admission and death databases was used to ascertain the end points of death, myocardial infarction, and target-vessel revascularization. We calculated propensity scores on the basis of clinical, demographic, and angiographic variables and matched DES to bare-metal stents on a 1:1 basis. The final study population consisted of 1642 patients, well matched for important covariables at baseline. Event-free survival was calculated over 24 months with the Kaplan-Meier method. All-cause death was more common after bare-metal stent implantation during follow-up (7.7% versus 6.6%; hazard ratio 0.63; 95% confidence interval, 0.40 to 0.99; P=0.04). No difference in the rates of myocardial infarction were noted (7.3% versus 7.5%; hazard ratio 1.02; 95% confidence interval, 0.69 to 1.54; P=0.92). Target-vessel revascularization was reduced in patients treated with DES (13.9% versus 10.7%; hazard ratio 0.67; 95% confidence interval, 0.49 to 0.93; P=0.02). At 24 months, patients treated with DES for off-label indications had lower rates of death and target-vessel revascularization and similar rates of myocardial infarction, as compared with patients treated with bare-metal stents.

New stent surface materials: the impact of polymer-dependent interactions of human endothelial cells, smooth muscle cells, and platelets.

PubMed

Busch, Raila; Strohbach, Anne; Rethfeldt, Stefanie; Walz, Simon; Busch, Mathias; Petersen, Svea; Felix, Stephan; Sternberg, Katrin

2014-02-01

Despite the development of new coronary stent technologies, in-stent restenosis and stent thrombosis are still clinically relevant. Interactions of blood and tissue cells with the implanted material may represent an important cause of these side effects. We hypothesize material-dependent interaction of blood and tissue cells. The aim of this study is accordingly to investigate the impact of vascular endothelial cells, smooth muscle cells and platelets with various biodegradable polymers to identify a stent coating or platform material that demonstrates excellent endothelial-cell-supportive and non-thrombogenic properties. Human umbilical venous endothelial cells, human coronary arterial endothelial cells and human coronary arterial smooth muscle cells were cultivated on the surfaces of two established biostable polymers used for drug-eluting stents, namely poly(ethylene-co-vinylacetate) (PEVA) and poly(butyl methacrylate) (PBMA). We compared these polymers to new biodegradable polyesters poly(l-lactide) (PLLA), poly(3-hydroxybutyrate) (P(3HB)), poly(4-hydroxybutyrate) (P(4HB)) and a polymeric blend of PLLA/P(4HB) in a ratio of 78/22% (w/w). Biocompatibility tests were performed under static and dynamic conditions. Measurement of cell proliferation, viability, glycocalix width, eNOS and PECAM-1 mRNA expression revealed strong material dependency among the six polymer samples investigated. Only the polymeric blend of PLLA/P(4HB) achieved excellent endothelial markers of biocompatibility. Data show that PLLA and P(4HB) tend to a more thrombotic response, whereas the polymer blend is characterized by a lower thrombotic potential. These data demonstrate material-dependent endothelialization, smooth muscle cell growth and thrombogenicity. Although polymers such as PEVA and PBMA are already commonly used for vascular implants, they did not sufficiently meet the criteria for biocompatibility. The investigated biodegradable polymeric blend PLLA/P(4HB) evidently represents a promising material for vascular stents and stent coatings. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Serial Versus Direct Dilation of Small Diameter Stents Results in a More Predictable and Complete Intentional Transcatheter Stent Fracture: A PICES Bench Testing Study.

PubMed

Crystal, Matthew A; Morgan, Gareth J; Danon, Saar; Gray, Robert G; Gruenstein, Daniel H; Gordon, Brent M; Goldstein, Bryan H

2018-01-01

Balloon-expandable stents, implanted in infants and children with congenital heart disease (CHD), often require redilation to match somatic growth. Small diameter stents may eventually require longitudinal surgical transection to prevent iatrogenic vascular stenosis. Intentional transcatheter stent fracture (TSF) is an emerging alternative approach to stent transection, but little is known about the optimal stent substrate and best protocol to improve the likelihood of successful TSF. Bench testing was performed with a stent dilation protocol. After recording baseline characteristics, stents were serially or directly dilated using ultra-high-pressure balloons (UHPB) until fracture occurred or further stent dilation was not possible. Stent characteristics recorded were as follows: cell design, metallurgy, mechanism, and uniformity of fracture. Stents tested included bare-metal coronary stents, premounted small diameter stents, and ePTFE-covered small diameter premounted stents. Ninety-four stents representing 9 distinct models were maximally dilated, with 80 (85%) demonstrating evidence of fracture. Comprehensive fracture details were recorded in 64 stents: linear and complete in 34/64 stents (53.1%), linear and incomplete in 9/64 stents (14.1%), transverse/complex and complete in 6/64 stents (9.4%), and transverse/complex and incomplete in 15/64 stents (23.4%). Stent fracture was not accomplished in some stent models secondary to significant shortening, i.e., "napkin-ring" formation. Serial dilation resulted in evidence of fracture in 62/67 (92.5%) stents compared with 18/27 (66.7%) stents in the direct dilation group (p = 0.003). Intentional TSF is feasible in an ex vivo model. Serial dilation more reliably expanded the stent and allowed for ultimate stent fracture, whereas direct large diameter dilation of stents was more likely to generate a "napkin-ring" configuration, which may be more resistant to fracture. In vivo animal and human testing is necessary to better understand the response to attempted TSF for newly developed stents as well as those currently in use.

Use of biliary stent in laparoscopic common bile duct exploration.

PubMed

Lyon, Matthew; Menon, Seema; Jain, Abhiney; Kumar, Harish

2015-05-01

It is well supported in the literature that laparoscopic common bile duct exploration (LCBDE) for choledocholithiasis has equal efficacy when compared to ERCP followed by laparoscopic cholecystectomy. Decompression after supra-duodenal choledochotomy is common practice as it reduced the risk of bile leaks. We conducted a prospective non-randomized study to compare outcomes and length of stay in patients undergoing biliary stent insertion versus T-tube drainage following LCBDE via choledochotomy. The study involved 116 patients with choledocholithiasis who underwent LCBDE and decompression of the biliary system by either ante-grade biliary stent or T-tube insertion. A 7 French straight/duodenal curve biliary Diagmed™ stent (9-11 cm) was placed in 82 patients (Biliary Stent Group). T-tube insertion was used for 34 patients (T-tube group). The length of hospital stay and complications for the selected patients were recorded. All trans-cystic common bile duct explorations were excluded from the study. The mean hospital stay for patients who underwent ante-grade biliary stent or T-tube insertion after LBCDE were 1 and 3.4 days, respectively. This is a statistically significant result with a p value of less than 0.001. Of the T-tube group, two patients required laparoscopic washout due to bile leaks, one had ongoing biliary stasis and one reported ongoing pain whilst the T-tube was in situ. A complication rate of 11.2%, this was a significant finding. There were no complications or concerns reported for the Biliary Stent Group. Our results show that there is a significant reduction in length of hospital stay and morbidity for patients that have ante-grade biliary stent decompression of the CBD post laparoscopic choledochotomy when compared T-tube drainage. This implies that ante-grade biliary stent insertion is likely to reduce costs and increase overall patient satisfaction. We support the use of ante-grade biliary stent insertion during LCBDE when primary closure is not preferred.

Metallic Zinc Exhibits Optimal Biocompatibility for Bioabsorbable Endovascular Stents

PubMed Central

Bowen, Patrick K.; Guillory, Roger J.; Shearier, Emily R.; Seitz, Jan-Marten; Drelich, Jaroslaw; Bocks, Martin; Zhao, Feng; Goldman, Jeremy

2015-01-01

Although corrosion resistant bare metal stents are considered generally effective, their permanent presence in a diseased artery is an increasingly recognized limitation due to the potential for long-term complications. We previously reported that metallic zinc exhibited an ideal biocorrosion rate within murine aortas, thus raising the possibility of zinc as a candidate base material for endovascular stenting applications. This study was undertaken to further assess the arterial biocompatibility of metallic zinc. Metallic zinc wires were punctured and advanced into the rat abdominal aorta lumen for up to 6.5 months. This study demonstrated that metallic zinc did not provoke responses that often contribute to restenosis. Low cell densities and neointimal tissue thickness, along with tissue regeneration within the corroding implant, point to optimal biocompatibility of corroding zinc. Furthermore, the lack of progression in neointimal tissue thickness over 6.5 months or the presence of smooth muscle cells near the zinc implant suggest that the products of zinc corrosion may suppress the activities of inflammatory and smooth muscle cells. PMID:26249616

"Accordion" deformity of a tortuous external iliac artery after stent-graft placement.

PubMed

Quinn, S F; Kim, J; Sheley, R C; Frankhouse, J H

2001-02-01

To identify a complication of endograft deployment in aneurysmal iliac arteries. A 71-year-old man was referred for endovascular treatment of a 60-mm-diameter right common iliac artery aneurysm; however, deployment of a homemade covered stent (Palmaz-Schatz and polytetrafluoroethylene) induced shortening of the tortuous external iliac artery, causing an "accordion" deformity. The anomaly proved difficult to treat with serial Wallstent deployment, because the convolution tightened and migrated caudally with each stent deployed, threatening outflow. Finally, after 3 Wallstents were implanted, the contour of the external iliac artery was straight, and flow was unimpeded. However, 3 weeks later, the external iliac artery had recoiled to its original redundant appearance, but flow remained satisfactory. The aneurysm remains excluded, with satisfactory distal flow after 24 months. Implanting endografts in redundant, tortuous arterial segments may prove problematic, since induced straightening by the device precipitates kinking in the redundant system. Although treatment may be required in some situations, the vessels may return to a noncompressed state by removing the delivery system and guidewire.

Early Clinical Results of a Novel Ab Interno Gel Stent for the Surgical Treatment of Open-angle Glaucoma.

PubMed

Sheybani, Arsham; Dick, H Burkhard; Ahmed, Iqbal I K

2016-07-01

To evaluate the intraocular pressure (IOP) lowering effect of the XEN140 microfistula gel stent implant for the surgical treatment of open-angle glaucoma. Forty-nine eyes of 49 patients with an IOP>18 mm Hg and ≤35 mm Hg were studied in a prospective nonrandomized multicenter cohort trial of the surgical implantation of the XEN140 implant in patients with open-angle glaucoma. Complete success was defined as a postoperative IOP≤18 mm Hg with ≥20% reduction in IOP at 12 months without any glaucoma medications. Failure was defined as vision loss of light perceptions vision or worse, need for additional glaucoma surgery, or <20% reduction of IOP from baseline. The average age was 64.3 (28.1 to 86.9) years old. Twenty-one eyes had prior failed trabeculectomy with mitomycin C surgery. IOP at 12 months decreased from a mean of 23.1 (±4.1) mm Hg to 14.7 (±3.7) mm Hg for a 36.4% reduction in IOP from baseline. The number of patients at 12 months who achieved an IOP≤18 mm Hg and ≥20% reduction in IOP was 40 (89%). The number of patients who achieved an IOP≤18 mm Hg and ≥20% reduction in IOP without antiglaucoma medications was 18 (40%). The XEN140 gel stent lowers IOP with few complications when implanted for the surgical treatment of open-angle glaucoma.

Management of antithrombotic therapy during cardiac implantable device surgery.

PubMed

AlTurki, Ahmed; Proietti, Riccardo; Birnie, David H; Essebag, Vidal

2016-06-01

Anticoagulants are commonly used drugs that are frequently encountered during device placement. Deciding when to halt or continue the use of anticoagulants is a balance between the risks of thromboembolism versus bleeding. Patients taking warfarin with a high risk of thromboembolism should continue to take their warfarin without interruption during device placement while ensuring their international normalized ratio remains below 3. For patients who are taking warfarin and have low risk of thromboembolism, either interrupted or continued warfarin may be used, with no evidence to clearly support either strategy. There is little evidence to support continuing direct acting oral anticoagulants (DOACs) for device implantation. The timing of halting these medications depends largely on renal function. If bleeding occurs, warfarin׳s anticoagulation effect is reversible with vitamin K and activated prothrombin complex concentrate. There are no DOAC reversal agents currently available, but some are under development. Regarding antiplatelet agents, aspirin alone can be safely continued while clopidogrel alone may also be continued, but with a slightly higher bleeding risk. Dual antiplatelet therapy for bare-metal stent/drug-eluting stent implanted within 4 weeks/6 months, respectively, should be continued due to high risk of stent thrombosis; however, if they are implanted after this period, then clopidogrel can be halted 5 days before the procedure and resumed soon after, while aspirin is continued. If the patient is taking both aspirin and warfarin, aspirin should be halted 5 days prior to the procedure, while warfarin is continued.

Late Complication after Superficial Femoral Artery (SFA) Aneurysm: Stent-graft Expulsion Outside the Skin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pecoraro, Felice, E-mail: felicepecoraro@libero.it; Sabatino, Ermanno R.; Dinoto, Ettore

A 78-year-old man presented with a 7-cm aneurysm in the left superficial femoral artery, which was considered unfit and anatomically unsuitable for conventional open surgery for multiple comorbidities. The patient was treated with stent-graft [Viabhan stent-graft (WL Gore and Associates, Flagstaff, AZ)]. Two years from stent-graft implantation, the patient presented a purulent secretion and a spontaneous external expulsion through a fistulous channel. No claudication symptoms or hemorrhagic signs were present. The pus and device cultures were positive for Staphylococcus aureus sensitive to piperacillin/tazobactam. Patient management consisted of fistula drainage, systemic antibiotic therapy, and daily wound dressing. At 1-month follow-up, themore » wound was closed. To our knowledge, this is the first case of this type of stent-graft complication presenting with external expulsion.« less

Successful silicon stent for life-threatening tracheal wall laceration.

PubMed

Yamamoto, Shinichi; Endo, Shunsuke; Endo, Tetsuya; Mitsuda, Sayaka

2013-01-01

We report an 86-year-old woman with a large tracheal laceration caused by tracheal intubation at cardiopulmonary arrest who underwent a successful stent procedure. Tracheal laceration developed in the membranous portion longitudinally 6 cm in length to 2 cm above the carina. Following 9 days' tracheal intubation, a Y-shaped silicon stent was inserted over the lacerated trachea. Four months after the stenting procedure, we removed the Y-shaped silicon stent from the healed membranous wall. The patient returned to daily life without requiring thoracotomy.

The role of stents in the treatment of congenital heart disease: Current status and future perspectives

PubMed Central

Peters, Bjoern; Ewert, Peter; Berger, Felix

2009-01-01

Intravascular or intracardiac stenoses occur in many forms of congenital heart disease (CHD). Therefore, the implantation of stents has become an accepted interventional procedure for stenotic lesions in pediatric cardiology. Furthermore, stents are know to be used to exclude vessel aneurysm or to ensure patency of existing or newly created intracardiac communications. With the further refinement of the first generation of devices, a variety of “modern” stents with different design characteristics have evolved. Despite the tremendous technical improvement over the last 20 years, the “ideal stent” has not yet been developed. Therefore, the pediatric interventionalist has to decide which stent is suitable for each lesion. On this basis, currently available stents are discussed in regard to their advantages and disadvantages for common application in CHD. New concepts and designs developed to overcome some of the existing problems, like the failure of adaptation to somatic growth, are presented. Thus, in the future, biodegradable or growth stents might replace the currently used generation of stents. This might truly lead to widening indications for the use of stents in the treatment of CHD. PMID:20300265

Hemodynamics in Transplant Renal Artery Stenosis and its Alteration after Stent Implantation Based on a Patient-specific Computational Fluid Dynamics Model.

PubMed

Wang, Hong-Yang; Liu, Long-Shan; Cao, Hai-Ming; Li, Jun; Deng, Rong-Hai; Fu, Qian; Zhang, Huan-Xi; Fei, Ji-Guang; Wang, Chang-Xi

Accumulating studies on computational fluid dynamics (CFD) support the involvement of hemodynamic factors in artery stenosis. Based on a patient-specific CFD model, the present study aimed to investigate the hemodynamic characteristics of transplant renal artery stenosis (TRAS) and its alteration after stent treatment. Computed tomography angiography (CTA) data of kidney transplant recipients in a single transplant center from April 2013 to November 2014 were reviewed. The three-dimensional geometry of transplant renal artery (TRA) was reconstructed from the qualified CTA images and categorized into three groups: the normal, stenotic, and stented groups. Hemodynamic parameters including pressure distribution, velocity, wall shear stress (WSS), and mass flow rate (MFR) were extracted. The data of hemodynamic parameters were expressed as median (interquartile range), and Mann-Whitney U-test was used for analysis. Totally, 6 normal, 12 stenotic, and 6 stented TRAs were included in the analysis. TRAS presented nonuniform pressure distribution, adverse pressure gradient across stenosis throat, flow vortex, and a separation zone at downstream stenosis. Stenotic arteries had higher maximal velocity and maximal WSS (2.94 [2.14, 3.30] vs. 1.06 [0.89, 1.15] m/s, 256.5 [149.8, 349.4] vs. 41.7 [37.8, 45.3] Pa at end diastole, P= 0.001; 3.25 [2.67, 3.56] vs. 1.65 [1.18, 1.72] m/s, 281.3 [184.3, 364.7] vs. 65.8 [61.2, 71.9] Pa at peak systole, P= 0.001) and lower minimal WSS and MFRs (0.07 [0.03, 0.13] vs. 0.52 [0.45, 0.67] Pa, 1.5 [1.0, 3.0] vs. 11.0 [8.0, 11.3] g/s at end diastole, P= 0.001; 0.08 [0.03, 0.19] vs. 0.70 [0.60, 0.81] Pa, 2.0 [1.3, 3.3] vs. 16.5 [13.0, 20.3] g/s at peak systole, P= 0.001) as compared to normal arteries. Stent implantation ameliorated all the alterations of the above hemodynamic factors except low WSS. Hemodynamic factors were significantly changed in severe TRAS. Stent implantation can restore or ameliorate deleterious change of hemodynamic factors except low WSS at stent regions.

Hemodynamics in Transplant Renal Artery Stenosis and its Alteration after Stent Implantation Based on a Patient-specific Computational Fluid Dynamics Model

PubMed Central

Wang, Hong-Yang; Liu, Long-Shan; Cao, Hai-Ming; Li, Jun; Deng, Rong-Hai; Fu, Qian; Zhang, Huan-Xi; Fei, Ji-Guang; Wang, Chang-Xi

2017-01-01

Background: Accumulating studies on computational fluid dynamics (CFD) support the involvement of hemodynamic factors in artery stenosis. Based on a patient-specific CFD model, the present study aimed to investigate the hemodynamic characteristics of transplant renal artery stenosis (TRAS) and its alteration after stent treatment. Methods: Computed tomography angiography (CTA) data of kidney transplant recipients in a single transplant center from April 2013 to November 2014 were reviewed. The three-dimensional geometry of transplant renal artery (TRA) was reconstructed from the qualified CTA images and categorized into three groups: the normal, stenotic, and stented groups. Hemodynamic parameters including pressure distribution, velocity, wall shear stress (WSS), and mass flow rate (MFR) were extracted. The data of hemodynamic parameters were expressed as median (interquartile range), and Mann–Whitney U-test was used for analysis. Results: Totally, 6 normal, 12 stenotic, and 6 stented TRAs were included in the analysis. TRAS presented nonuniform pressure distribution, adverse pressure gradient across stenosis throat, flow vortex, and a separation zone at downstream stenosis. Stenotic arteries had higher maximal velocity and maximal WSS (2.94 [2.14, 3.30] vs. 1.06 [0.89, 1.15] m/s, 256.5 [149.8, 349.4] vs. 41.7 [37.8, 45.3] Pa at end diastole, P = 0.001; 3.25 [2.67, 3.56] vs. 1.65 [1.18, 1.72] m/s, 281.3 [184.3, 364.7] vs. 65.8 [61.2, 71.9] Pa at peak systole, P = 0.001) and lower minimal WSS and MFRs (0.07 [0.03, 0.13] vs. 0.52 [0.45, 0.67] Pa, 1.5 [1.0, 3.0] vs. 11.0 [8.0, 11.3] g/s at end diastole, P = 0.001; 0.08 [0.03, 0.19] vs. 0.70 [0.60, 0.81] Pa, 2.0 [1.3, 3.3] vs. 16.5 [13.0, 20.3] g/s at peak systole, P = 0.001) as compared to normal arteries. Stent implantation ameliorated all the alterations of the above hemodynamic factors except low WSS. Conclusions: Hemodynamic factors were significantly changed in severe TRAS. Stent implantation can restore or ameliorate deleterious change of hemodynamic factors except low WSS at stent regions. PMID:28051019

In-situ laser fenestration of endovascular stent-graft in abdominal aortic aneurysm repair (EVAR)

NASA Astrophysics Data System (ADS)

Micheletti, Filippo; Pini, Roberto; Piazza, Roberta; Ferrari, Vincenzo; Condino, Sara; Rossi, Francesca

2017-02-01

Endovascular abdominal aortic aneurysms repair (EVAR) involves the minimally invasive implantation of a stent-graft within the aorta to exclude the aneurysm from the circulation thus preventing its rupture. The feasibility of such operation is highly dependent on the aorta morphology and in general the presence of one/both renal arteries emerging from the aneurysm is the absolute limit for the implantation of a standard stent-graft. Consequently, classical intervention methods involve the implantation of a custom-made graft with fenestrations, leading to extremely complicated surgeries with high risks for the patient and high costs. Recent techniques introduced the use of standard grafts (i.e. without fenestrations) in association with mechanical in-situ fenestration, but this procedure is limited principally by the brittleness and low stability of the environment, in addition to the difficulty of controlling the guidance of the endovascular tools due to the temporarily block of the blood flow. In this work we propose an innovative EVAR strategy, which involves in-situ fenestration with a fiber guided laser tool, controlled via an electromagnetic navigation system. The fiber is sensorized to be tracked by means of the driving system and, using a 3D model of the patient anatomy, the surgeon can drive the fiber to the aneurysm, where the stent has been previously released, to realize the proper fenestration(s). The design and construction of the catheter laser tool will be presented, togheter with preliminary fenestration tests on graft-materials, including the effects due to the presence of blood and tissues.

Results of transcatheter pulmonary valvulation in native or patched right ventricular outflow tracts.

PubMed

Malekzadeh-Milani, Sophie; Ladouceur, Magalie; Cohen, Sarah; Iserin, Laurence; Boudjemline, Younes

2014-11-01

Although widely accepted worldwide, indications for percutaneous valve replacement are limited to treatment of dysfunction of prosthetic conduits inserted in the right ventricular outflow tract (RVOT). There has been little evaluation of the use of the Melody(®) valve for patched non-circular pulmonary pathways. To evaluate the outcomes of Melody valve insertion in patients with a patched non-circular RVOT. We analysed procedural and outcomes data from 34 patients who underwent Melody valve implantation for a non-circular RVOT. RVOT preparation was done in all patients, using different techniques (conventional, Russian doll and/or PA jailing). Melody valve insertion was performed concomitantly in most patients. All procedures were successful. Sixteen patients had complex additional procedures, including the jailing technique (n=5), the Russian doll technique (n=6) and multiple stent implantations (Russian jailing; n=5). The remaining patients were treated using the conventional technique with systematic prestenting. Three early complications occurred: one haemoptysis; one residual RVOT obstruction needing recatheterization 48 hours after percutaneous pulmonary valve implantation; and one stent embolization during advancement of the Ensemble(®) delivery system. The mean follow-up period was 2.6 years postprocedure. There was no stent fracture, migration or embolization. Two patients developed a significant paraprosthetic leak and one received a second Melody valve. Careful patient selection, balloon sizing and RVOT preparation with prestenting are required to create a safe landing zone for the Melody valve. Short-term follow-up shows excellent results with no stent fracture or migration and appears promising. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Combined Endovascular Repair of a Celiac Trunk Aneurysm Using Celiac-Splenic Stent Graft and Hepatic Artery Embolization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carrafiello, Giampaolo; Rivolta, Nicola; Fontana, Federico

2010-04-15

Celiac trunk aneurysms are rare and usually asymptomatic lesions. However, treatment is generally warranted to avoid catastrophic rupture. We report a case of a 70-year-old man who sought care for a celiac trunk aneurysm close to the hepatosplenic bifurcation managed endovascularly by using a combined treatment of celiac-splenic stent-graft implantation and hepatic artery embolization.

ABSORB II randomized controlled trial: a clinical evaluation to compare the safety, efficacy, and performance of the Absorb everolimus-eluting bioresorbable vascular scaffold system against the XIENCE everolimus-eluting coronary stent system in the treatment of subjects with ischemic heart disease caused by de novo native coronary artery lesions: rationale and study design.

PubMed

Diletti, Roberto; Serruys, Patrick W; Farooq, Vasim; Sudhir, Krishnankutty; Dorange, Cecile; Miquel-Hebert, Karine; Veldhof, Susan; Rapoza, Richard; Onuma, Yoshinobu; Garcia-Garcia, Hector M; Chevalier, Bernard

2012-11-01

Currently, no data are available on the direct comparison between the Absorb everolimus-eluting bioresorbable vascular scaffold (Absorb BVS) and conventional metallic drug-eluting stents. The ABSORB II study is a randomized, active-controlled, single-blinded, multicenter clinical trial aiming to compare the second-generation Absorb BVS with the XIENCE everolimus-eluting metallic stent. Approximately 501 subjects will be enrolled on a 2:1 randomization basis (Absorb BVS/XIENCE stent) in approximately 40 investigational sites across Europe and New Zealand. Treated lesions will be up to 2 de novo native coronary artery lesions, each located in different major epicardial vessels, all with an angiographic maximal luminal diameter between 2.25 and 3.8 mm as estimated by online quantitative coronary angiography (QCA) and a lesion length of ≤48 mm. Clinical follow-up is planned at 30 and 180 days and at 1, 2, and 3 years. All subjects will undergo coronary angiography, intravascular ultrasound (IVUS) and IVUS-virtual histology at baseline (pre-device and post-device implantation) and at 2-year angiographic follow-up. The primary end point is superiority of the Absorb BVS vs XIENCE stent in terms of vasomotor reactivity of the treated segment at 2 years, defined as the QCA quantified change in the mean lumen diameter prenitrate and postnitrate administration. The coprimary end point is the noninferiority (reflex to superiority) of the QCA-derived minimum lumen diameter at 2 years postnitrate minus minimum lumen diameter postprocedure postnitrate by QCA. In addition, all subjects allocated to the Absorb BVS group will undergo multislice computed tomography imaging at 3 years. The ABSORB II randomized controlled trial (ClinicalTrials.gov NCT01425281) is designed to compare the safety, efficacy, and performance of Absorb BVS against the XIENCE everolimus-eluting stent in the treatment of de novo native coronary artery lesions. Copyright © 2012 Mosby, Inc. All rights reserved.

Cutaneous and systemic hypersensitivity reactions to metallic implants.

PubMed

Basko-Plluska, Juliana L; Thyssen, Jacob P; Schalock, Peter C

2011-01-01

Cutaneous reactions to metal implants, orthopedic or otherwise, are well documented in the literature. The first case of a dermatitis reaction over a stainless steel fracture plate was described in 1966. Most skin reactions are eczematous and allergic in nature, although urticarial, bullous, and vasculitic eruptions may occur. Also, more complex immune reactions may develop around the implants, resulting in pain, inflammation, and loosening. Nickel, cobalt, and chromium are the three most common metals that elicit both cutaneous and extracutaneous allergic reactions from chronic internal exposure. However, other metal ions as well as bone cement components can cause such hypersensitivity reactions. To complicate things, patients may also develop delayed-type hypersensitivity reactions to metals (ie, in-stent restenosis, prosthesis loosening, inflammation, pain, or allergic contact dermatitis) following the insertion of intravascular stents, dental implants, cardiac pacemakers, or implanted gynecologic devices. Despite repeated attempts by researchers and clinicians to further understand this difficult area of medicine, the association between metal sensitivity and cutaneous allergic reactions remains to be fully understood. This review provides an update of the current knowledge in this field and should be valuable to health care providers who manage patients with conditions related to this field.

A new one-step procedure for pulmonary valve implantation of the melody valve: Simultaneous prestenting and valve implantation.

PubMed

Boudjemline, Younes

2018-01-01

To describe a new modification, the one-step procedure, that allows interventionists to pre-stent and implant a Melody valve simultaneously. Percutaneous pulmonary valve implantation (PPVI) is the standard of care for managing patients with dysfunctional right ventricular outflow tract, and the approach is standardized. Patients undergoing PPVI using the one-step procedure were identified in our database. Procedural data and radiation exposure were compared to those in a matched group of patients who underwent PPVI using the conventional two-step procedure. Between January 2016 and January 2017, PPVI was performed in 27 patients (median age/range, 19.1/10-55 years) using the one-step procedure involving manual crimping of one to three bare metal stents over the Melody valve. The stent and Melody valve were delivered successfully using the Ensemble delivery system. No complications occurred. All patients had excellent hemodynamic results (median/range post-PPVI right ventricular to pulmonary artery gradient, 9/0-20 mmHg). Valve function was excellent. Median procedural and fluoroscopic times were 56 and 10.2 min, respectively, which significantly differed from those of the two-step procedure group. Similarly, the dose area product (DAP), and radiation time were statistically lower in the one-step group than in the two-step group (P < 0.001 for all variables). After a median follow-up of 8 months (range, 3-14.7), no patient underwent reintervention, and no device dysfunction was observed. The one-step procedure is a safe modification that allows interventionists to prestent and implants the Melody valve simultaneously. It significantly reduces procedural and fluoroscopic times, and radiation exposure. © 2017 Wiley Periodicals, Inc.

Evaluation of functionality and biological response of the multilayer flow modulator in porcine animal models.

PubMed

Sultan, Sherif; Kavanagh, Edel P; Hynes, Niamh; Diethrich, Edward B

2016-02-01

This study outlines the use of non-aneurysmal porcine animal models to study device functionality and biological response of the Multilayer Flow Modulator (MFM) (Cardiatis, Isnes, Belgium), with an emphasis on preclinical device functionality and biological response characteristics in an otherwise healthy aorta. Twelve animals were implanted with the study device in the abdominal aorta, in 6 animals for 1 month and 6 animals for 6 months. Upon completion of the study period, each animal underwent a necropsy to examine how the implanted device had affected the artery and surrounding tissue. Neointima and stenosis formation were recorded via morphometry, and endothelialization via histopathological analysis. The MFM devices were delivered to their respective implantation sites without difficulty. Six of the implanted stents were oversized with percentages ranging from 2.6% to 18.8%. Statistical analysis was carried out and showed no significance between the regular sized stent group and oversized stent group for neointimal area (P=0.17), neointimal thickness (P=0.17), and percentage area stenosis (P=0.65). Histopathological findings showed in most areas flattened endothelium like cells lined the luminal surface of the neointima. Scanning electron microscopy also showed the devices were well tolerated, inciting only a minimal neointimal covering and little fibrin or platelet deposition. Neointimal thickness of 239.7±55.6 μm and 318.3±130.4 μm, and percentage area stenosis of 9.6±2.6% and 12.6±5% were recorded at 1 and 6 months respectively. No statistical differences were found between these results. The MFM devices were delivered to their respective implantation sites without difficulty and incited little neointimal and stenosis formation in the aorta, affirming its functionality and biocompatibility.

[The application of Y-shaped self-expandable covered metal stents in the thoracostomach-airway fistula: a single center, 11 years experience].

PubMed

Fang, Yi; Li, Tengfei; Han, Xinwei; Wu, Gang; Ren, Jianzhuang; Ren, Kewei; Lu, Huibin; Zhang, Quanhui; Li, Zongming

2015-08-01

To investigate the clinical feasibility and efficacy of Y-shaped self-expandable covered metal stents (Y-stents) in the management of thoracostomach-airway fistula. Retrospective analysis was performed for 108 patients treated for thoracostomach-airway fistula with Y-shaped self-expandable coated metal stents between April 2003 and October 2014. Y-stents were designed based on the dimensions of trachea and bronchus and sites of the fistula and then were inserted under DSA monitoring. There were 65 cases with single big Y-stent placement, 26 cases with single small Y-stent placement, 23 cases with double Y-stents placement, and 1 case with 3 Y-stents placement. Stent implantation was successfully accomplished with single manipulation in all patients. Complete occlusion of the fistula was obtained in 104 patients after the primary manipulation, and 4 patients required a secondary manipulation where a double Y-stents was inserted because of failure of primary manipulate. Ninety-two patients completed the follow-up , while 16 were lost. Fifty-nine patients died while 33 were alive with marked improvement in their quality of life. The placement of Y-stents can effectively occlude the thoracostomach-airway fistula in patients who had had the esophageal tumors resected. The technique is not only feasible but reliable to improve the quality of life of the patients.

High-definition computed tomography for coronary artery stents imaging: Initial evaluation of the optimal reconstruction algorithm.

PubMed

Cui, Xiaoming; Li, Tao; Li, Xin; Zhou, Weihua

2015-05-01

The aim of this study was to evaluate the in vivo performance of four image reconstruction algorithms in a high-definition CT (HDCT) scanner with improved spatial resolution for the evaluation of coronary artery stents and intrastent lumina. Thirty-nine consecutive patients with a total of 71 implanted coronary stents underwent coronary CT angiography (CCTA) on a HDCT (Discovery CT 750 HD; GE Healthcare) with the high-resolution scanning mode. Four different reconstruction algorithms (HD-stand, HD-detail; HD-stand-plus; HD-detail-plus) were applied to reconstruct the stented coronary arteries. Image quality for stent characterization was assessed. Image noise and intrastent luminal diameter were measured. The relationship between the measurement of inner stent diameter (ISD) and the true stent diameter (TSD) and stent type were analysed. The stent-dedicated kernel (HD-detail) offered the highest percentage (53.5%) of good image quality for stent characterization and the highest ratio (68.0±8.4%) of visible stent lumen/true stent lumen for luminal diameter measurement at the expense of an increased overall image noise. The Pearson correlation coefficient between the ISD and TSD measurement and spearman correlation coefficient between the ISD measurement and stent type were 0.83 and 0.48, respectively. Compared with standard reconstruction algorithms, high-definition CT imaging technique with dedicated high-resolution reconstruction algorithm provides more accurate stent characterization and intrastent luminal diameter measurement. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Removable esophageal stents have poor efficacy for the treatment of refractory benign esophageal strictures (RBES).

PubMed

Dan, D T; Gannavarapu, B; Lee, J G; Chang, K; Muthusamy, V R

2014-08-01

With the recent availability of removable esophageal stents, endoscopic stenting has been utilized to treat refractory benign esophageal strictures (RBES). The objective of this study was to review the feasibility and effectiveness of removable esophageal stents to treat RBES. Patients who received removable esophageal stents for the treatment of RBES at the institution between 2004-2010 using its stent implantation logs and endoscopic database were retrospectively identified. Patient demographics, stricture etiology and location, stent and procedure characteristics, and clinical outcomes were obtained. Twenty-five patients with a mean age of 70 (72% male) underwent initial stent placement; 24 were successful. Overall clinical success was achieved in five of the 19 patients (26%) ultimately undergoing stent removal. RBES etiologies included anastomotic (13), radiation (5), peptic (3), chemotherapy (1), scleroderma (1), and unknown (2). Alimaxx-E (Merit-Endotek, South Jordan, UT, USA) stents were placed in 20 patients and Polyflex (Boston Scientific, Natick, MA, USA) stents were used in five patients. Immediate complications included failed deployment (1) and chest pain (7). Five patients died prior to stent removal. Stent migration was found in 53% (10/19) of patients who underwent stent removal: nine required additional therapy and one had symptom resolution. Out of the nine patients without stent migration, five required additional therapy and four had symptom resolution. Although placement of removable esophageal stents for RBES is technically feasible, it is frequently complicated by stent migration and chest pain. In addition, few patients achieved long-term stricture resolution after initial stenting. In this study, most patients ultimately required repeated stenting and/or dilations to maintain relief of dysphagia. © 2012 Copyright the Authors. Journal compilation © 2012, Wiley Periodicals, Inc. and the International Society for Diseases of the Esophagus.

Dual Antiplatelet Therapy for 6 Versus 18 Months After Biodegradable Polymer Drug-Eluting Stent Implantation.

PubMed

Nakamura, Masato; Iijima, Raisuke; Ako, Junya; Shinke, Toshiro; Okada, Hisayuki; Ito, Yoshiaki; Ando, Kenji; Anzai, Hitoshi; Tanaka, Hiroyuki; Ueda, Yasunori; Takiuchi, Shin; Nishida, Yasunori; Ohira, Hiroshi; Kawaguchi, Katsuhiro; Kadotani, Makoto; Niinuma, Hiroyuki; Omiya, Kazuto; Morita, Takashi; Zen, Kan; Yasaka, Yoshinori; Inoue, Kenji; Ishiwata, Sugao; Ochiai, Masahiko; Hamasaki, Toshimitsu; Yokoi, Hiroyoshi

2017-06-26

The NIPPON (Nobori Dual Antiplatelet Therapy as Appropriate Duration) study was a multicenter randomized investigation of the noninferiority of short-term versus long-term dual antiplatelet therapy (DAPT) in patients with implantation of the Nobori drug-eluting stent (DES) (Terumo, Tokyo, Japan), which has a biodegradable abluminal coating. The optimum duration of DAPT for patients with a biodegradable polymer-coated DES is unclear. The subjects were 3,773 patients with stable or acute coronary syndromes undergoing Nobori stent implantation. They were randomized 1:1 to receive DAPT for 6 or 18 months. The primary endpoint was net adverse clinical and cerebrovascular events (NACCE) (all-cause mortality, myocardial infarction, stroke, and major bleeding) from 6 to 18 months after stenting. Intention-to-treat analysis was performed in 3,307 patients who were followed for at least 6 months. NACCE occurred in 34 patients (2.1%) receiving short-term DAPT and 24 patients (1.5%) receiving long-term DAPT (difference 0.6%, 95% confidence interval [CI]: 1.5 to 0.3). Because the lower limit of the 95% CI was inside the specified margin of -2%, noninferiority of short-term DAPT was confirmed. Mortality was 1.0% with short-term DAPT versus 0.4% with long-term DAPT, whereas myocardial infarction was 0.2% versus 0.1%, and major bleeding was 0.7% versus 0.7%, respectively. The estimated probability of NACCE was lower in the long-term DAPT group (hazard ratio: 1.44, 95% CI: 0.86 to 2.43). Six months of DAPT was not inferior to 18 months of DAPT following implantation of a DES with a biodegradable abluminal coating. However, this result needs to be interpreted with caution given the open-label design and wide noninferiority margin of the present study. (Nobori Dual Antiplatelet Therapy as Appropriate Duration [NIPPON]; NCT01514227). Copyright © 2017. Published by Elsevier Inc.

Transcatheter Pulmonary Valve Replacement by Hybrid Approach Using a Novel Polymeric Prosthetic Heart Valve: Proof of Concept in Sheep

PubMed Central

Xu, Tong-yi; Zhang, Zhi-gang; Li, Xin; Han, Lin; Xu, Zhi-yun

2014-01-01

Background Since 2000, transcatheter pulmonary valve replacement has steadily advanced. However, the available prosthetic valves are restricted to bioprosthesis which have defects like poor durability. Polymeric heart valve is thought as a promising alternative to bioprosthesis. In this study, we introduced a novel polymeric transcatheter pulmonary valve and evaluated its feasibility and safety in sheep by a hybrid approach. Methods We designed a novel polymeric trileaflet transcatheter pulmonary valve with a balloon-expandable stent, and the valve leaflets were made of 0.1-mm expanded polytetrafluoroethylene (ePTFE) coated with phosphorylcholine. We chose glutaraldehyde-treated bovine pericardium valves as control. Pulmonary valve stents were implanted in situ by a hybrid transapical approach in 10 healthy sheep (8 for polymeric valve and 2 for bovine pericardium valve), weighing an average of 22.5±2.0 kg. Angiography and cardiac catheter examination were performed after implantation to assess immediate valvular functionality. After 4-week follow-up, angiography, echocardiography, computed tomography, and cardiac catheter examination were used to assess early valvular function. One randomly selected sheep with polymeric valve was euthanized and the explanted valved stent was analyzed macroscopically and microscopically. Findings Implantation was successful in 9 sheep. Angiography at implantation showed all 9 prosthetic valves demonstrated orthotopic position and normal functionality. All 9 sheep survived at 4-week follow-up. Four-week follow-up revealed no evidence of valve stent dislocation or deformation and normal valvular and cardiac functionality. The cardiac catheter examination showed the peak-peak transvalvular pressure gradient of the polymeric valves was 11.9±5.0 mmHg, while that of two bovine pericardium valves were 11 and 17 mmHg. Gross morphology demonstrated good opening and closure characteristics. No thrombus or calcification was seen macroscopically. Conclusions This design of the novel ePTFE transcatheter pulmonary valve is safe and effective to deploy in sheep by hybrid approach, and the early valvular functionality is good. PMID:24926892

Experimental and theoretical studies of implant assisted magnetic drug targeting

NASA Astrophysics Data System (ADS)

Aviles, Misael O.

One way to achieve drug targeting in the body is to incorporate magnetic nanoparticles into drug carriers and then retain them at the site using an externally applied magnetic field. This process is referred to as magnetic drug targeting (MDT). However, the main limitation of MDT is that an externally applied magnetic field alone may not be able to retain a sufficient number of magnetic drug carrier particles (MDCPs) to justify its use. Such a limitation might not exist when high gradient magnetic separation (HGMS) principles are applied to assist MDT by means of ferromagnetic implants. It was hypothesized that an Implant Assisted -- MDT (IA-MDT) system would increase the retention of the MDCPs at a target site where an implant had been previously located, since the magnetic forces are produced internally. With this in mind, the overall objective of this work was to demonstrate the feasibility of an IA-MDT system through mathematical modeling and in vitro experimentation. The mathematical models were developed and used to demonstrate the behavior and limitations of IA-MDT, and the in vitro experiments were designed and used to validate the models and to further elucidate the important parameters that affect the performance of the system. IA-MDT was studied with three plausible implants, ferromagnetic stents, seed particles, and wires. All implants were studied theoretically and experimentally using flow through systems with polymer particles containing magnetite nanoparticles as MDCPs. In the stent studies, a wire coil or mesh was simply placed in a flow field and the capture of the MDCPs was studied. In the other cases, a porous polymer matrix was used as a surrogate capillary tissue scaffold to study the capture of the MDCPs using wires or particle seeds as the implant, with the seeds either fixed within the polymer matrix or captured prior to capturing the MDCPs. An in vitro heart tissue perfusion model was also used to study the use of stents. In general, all the results demonstrated that IA-MDT is indeed feasible and that careful modification of the MDCP properties and implant properties are fundamental to the success of this technology.

Numerical Study of Blood Clots Influence on the Flow Pattern and Platelet Activation on a Stented Bifurcation Model.

PubMed

García Carrascal, P; García García, J; Sierra Pallares, J; Castro Ruiz, F; Manuel Martín, F J

2017-05-01

Stent implantation is a common procedure followed in arteries affected by atherosclerosis. This procedure can lead to other stenting-related problems. One of these is the deposition and accumulation of blood clots over stent struts. This process can have further consequences, in so far as it can introduce modifications to the flow pattern. This problem is especially critical in stented bifurcations, where resulting stent geometry is more complex. In this regard, a numerical study is presented of the effect on the flow pattern and platelet activation of blood clot depositions on the stent struts of a stented coronary bifurcation. The numerical model is first validated with experimental measurements performed for this purpose. Experiments considered a flow with suspended artificial thrombi, which naturally deposited on stent struts. The location and shape observed were used to create numerical thrombi. Following this, numerical simulations were performed to analyze the influence of the presence of thrombi depositions on parameters such as Time Averaged Wall Shear Stress, Oscillatory Shear Index or Relative Residence Time. Finally, a study was also carried out of the effect of different geometrical configurations, from a straight tube to a stented bifurcation model with thrombus depositions, on platelet activation.

A planning system for transapical aortic valve implantation

NASA Astrophysics Data System (ADS)

Gessat, Michael; Merk, Denis R.; Falk, Volkmar; Walther, Thomas; Jacobs, Stefan; Nöttling, Alois; Burgert, Oliver

2009-02-01

Stenosis of the aortic valve is a common cardiac disease. It is usually corrected surgically by replacing the valve with a mechanical or biological prosthesis. Transapical aortic valve implantation is an experimental minimally invasive surgical technique that is applied to patients with high operative risk to avoid pulmonary arrest. A stented biological prosthesis is mounted on a catheter. Through small incisions in the fifth intercostal space and the apex of the heart, the catheter is positioned under flouroscopy in the aortic root. The stent is expanded and unfolds the valve which is thereby implanted into the aortic root. Exact targeting is crucial, since major complications can arise from a misplaced valve. Planning software for the perioperative use is presented that allows for selection of the best fitting implant and calculation of the safe target area for that implant. The software uses contrast enhanced perioperative DynaCT images acquired under rapid pacing. In a semiautomatic process, a surface segmentation of the aortic root is created. User selected anatomical landmarks are used to calculate the geometric constraints for the size and position of the implant. The software is integrated into a PACS network based on DICOM communication to query and receive the images and implants templates from a PACS server. The planning results can be exported to the same server and from there can be rertieved by an intraoperative catheter guidance device.

Feasibility study using a Ni-Ti stent and electronic portal imaging to localize the prostate during radiotherapy.

PubMed

Carl, Jesper; Lund, Bente; Larsen, Erik Hoejkjaer; Nielsen, Jane

2006-02-01

A new method for localization of the prostate during external beam radiotherapy is presented. The method is based on insertion of a thermo-expandable Ni-Ti stent. The stent is originally developed for treatment of bladder outlet obstruction caused by benign hyperplasia. The radiological properties of the stent are used for precise prostate localization during treatment using electronic portal images. Patients referred for intended curative radiotherapy and having a length of their prostatic urethra in the range from 25 to 65 mm were included. Pairs of isocentric orthogonal portal images were used to determine the 3D position at eight different treatment sessions for each patient. Fourteen patients were enrolled in the study. The data obtained demonstrated that the stent position was representative of the prostate location. The stent may also improve delineation of the prostate GTV, and prevent obstruction of bladder outlet during treatment. Precision in localization of the stent was less than 1 mm. Random errors in stent position were left-right 1.6 mm, cranial-caudal 2.2 mm and anterior-posterior 3.2 mm. In four of 14 patients a dislocation of the stent to the bladder occurred. Dislocation only occurred in patients with length of prostatic urethra less than 40 mm. A new method for radiological high precision localization of the prostate during radiotherapy is presented. The method is based on insertion of a standard Ni-Ti thermo-expandable stent, designed for treatment of benign prostate hyperplasia.

Chronic impedance spectroscopy of an endovascular stent-electrode array

NASA Astrophysics Data System (ADS)

Opie, Nicholas L.; John, Sam E.; Rind, Gil S.; Ronayne, Stephen M.; Grayden, David B.; Burkitt, Anthony N.; May, Clive N.; O'Brien, Terence J.; Oxley, Thomas J.

2016-08-01

Objective. Recently, we reported a minimally invasive stent-electrode array capable of recording neural signals from within a blood vessel. We now investigate the use of electrochemical impedance spectroscopy (EIS) measurements to infer changes occurring to the electrode-tissue interface from devices implanted in a cohort of sheep for up to 190 days. Approach. In a cohort of 15 sheep, endovascular stent-electrode arrays were implanted in the superior sagittal sinus overlying the motor cortex for up to 190 days. EIS was performed routinely to quantify viable electrodes for up to 91 days. An equivalent circuit model (ECM) was developed from the in vivo measurements to characterize the electrode-tissue interface changes occurring to the electrodes chronically implanted within a blood vessel. Post-mortem histological assessment of stent and electrode incorporation into the wall of the cortical vessels was compared to the electrical impedance measurements. Main results. EIS could be used to infer electrode viability and was consistent with x-ray analysis performed in vivo, and post-mortem evaluation. Viable electrodes exhibited consistent 1 kHz impedances across the 91 day measurement period, with the peak resistance frequency for the acquired data also stable over time. There was a significant change in 100 Hz phase angles, increasing from -67.8° ± 8.8° at day 0 to -43.8° ± 0.8° at day 91, which was observed to stabilize after eight days. ECM’s modeled to the data suggested this change was due to an increase in the capacitance of the electrode-tissue interface. This was supported by histological assessment with >85% of the implanted stent struts covered with neointima and incorporated into the blood vessel within two weeks. Conclusion. This work demonstrated that EIS could be used to determine the viability of electrode implanted chronically within a blood vessel. Impedance measurements alone were not observed to be a useful predictor of alterations occurring at the electrode tissue interface. However, measurement of 100 Hz phase angles was in good agreement with the capacitive changes predicted by the ECM and consistent with suggestions that this represents protein absorption on the electrode surface. 100 Hz phase angles stabilized after 8 days, consistent with histologically assessed samples. Significance. These findings demonstrate the potential application of this technology for use as a chronic neural recording system and indicate the importance of conducting EIS as a measure to identify viable electrodes and changes occurring at the electrode-tissue interface.

Transmyocardial drilling revascularization combined with heparinized bFGF-incorporating stent activates resident cardiac stem cells via SDF-1/CXCR4 axis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Guang-Wei; Wen, Ti; Gu, Tian-Xiang, E-mail: cmugtx@sina.com

Objective: To investigate whether transmyocardial drilling revascularization combined with heparinized basic fibroblast growth factor (bFGF)-incorporating degradable stent implantation (TMDRSI) can promote myocardial regeneration after acute myocardial infarction (AMI). Methods: A model of AMI was generated by ligating the mid-third of left anterior descending artery (LAD) of miniswine. After 6 h, the animals were divided into none-treatment (control) group (n = 6) and TMDRSI group (n = 6). For TMDRSI group, two channels with 3.5 mm in diameter were established by a self-made drill in the AMI region, into which a stent was implanted. Expression of stromal cell-derived factor-1{sub {alpha}} (SDF-1{submore » {alpha}}) and CXC chemokine receptor 4 (CXCR4), cardiac stem cell (CSC)-mediated myocardial regeneration, myocardial apoptosis, myocardial viability, and cardiac function were assessed at various time-points. Results: Six weeks after the operation, CSCs were found to have differentiated into cardiomyocytes to repair the infarcted myocardium, and all above indices showed much improvement in the TMDRSI group compared with the control group (P < 0.001). Conclusions: The new method has shown to be capable of promoting CSCs proliferation and differentiation into cardiomyocytes through activating the SDF-1/CXCR4 axis, while inhibiting myocardial apoptosis, thereby enhancing myocardial regeneration following AMI and improving cardiac function. This may provide a new strategy for myocardial regeneration following AMI. -- Highlights: Black-Right-Pointing-Pointer The effects of TMDR and bFGF-stent on myocardial regeneration were studied in a pig model of AMI. Black-Right-Pointing-Pointer TMDR and bFGF-stent implantation activated CSCs via the SDF-1/CXCR4 axis. Black-Right-Pointing-Pointer CSC-mediated myocardial regeneration improved cardiac function. Black-Right-Pointing-Pointer It may be a new therapeutic strategy for AMI.« less

Evaluation of XIENCE V everolimus-eluting and Taxus Express2 paclitaxel-eluting coronary stents in patients with jailed side branches from the SPIRIT IV trial at 2 years.

PubMed

Forrest, John K; Lansky, Alexandra J; Meller, Stephanie M; Hou, Liming; Sood, Poornima; Applegate, Robert J; Wang, John C; Skelding, Kimberly A; Shah, Aakar; Kereiakes, Dean J; Sudhir, Krishnankutty; Cristea, Ecaterina; Yaqub, Manejeh; Stone, Gregg W

2013-06-01

The aim of this study was to determine whether patients from the Clinical Evaluation of the XIENCE V Everolimus Eluting Coronary Stent System in the Treatment of Patients With de Novo Native Coronary Artery Lesions (SPIRIT) IV trial who underwent percutaneous coronary intervention, who had target lesions with jailed side branches, had improved clinical outcomes when treated with the XIENCE V versus Taxus Express(2) drug-eluting stent. In the SPIRIT III randomized trial, patients with target lesions with jailed side branches after XIENCE V compared with Taxus Express(2) implantation had lower 2-year rates of major adverse cardiac events. The SPIRIT IV trial represents a larger more diverse patient population compared with SPIRIT III. In the large-scale, prospective, multicenter, randomized SPIRIT IV trial, 3,687 patients who underwent coronary stenting with up to 3 de novo native coronary artery lesions were randomized 2:1 to receive XIENCE V versus Taxus Express(2) stents. Two-year clinical outcomes of patients with or without jailed side branches after stenting were compared. A jailed side branch was defined as any side branch >1.0 mm in diameter within the target segment being stented, excluding bifurcations deemed to require treatment. Of the 3,687 patients in SPIRIT IV, a total of 1,426 had side branches that were jailed during angioplasty of the target lesion. Patients with jailed side branches after XIENCE V compared with Taxus Express(2) implantation had significantly lower 2-year rates of target lesion failure (6.5% vs 11.9%, p = 0.001), major adverse cardiac events (6.6% vs 12.2%, p = 0.0008), ischemia-driven target vessel revascularization (4.1% vs 7.9%, p = 0.004), and stent thrombosis (0.6% vs 2.8%, p = 0.001). In conclusion, patients with jailed side branches after stenting with XIENCE V compared to Taxus Express(2) devices had superior clinical outcomes at 2 years in the large-scale randomized SPIRIT IV trial. Copyright © 2013 Elsevier Inc. All rights reserved.

4D phase contrast flow imaging for in-stent flow visualization and assessment of stent patency in peripheral vascular stents--a phantom study.

PubMed

Bunck, Alexander C; Jüttner, Alena; Kröger, Jan Robert; Burg, Matthias C; Kugel, Harald; Niederstadt, Thomas; Tiemann, Klaus; Schnackenburg, Bernhard; Crelier, Gerard R; Heindel, Walter; Maintz, David

2012-09-01

4D phase contrast flow imaging is increasingly used to study the hemodynamics in various vascular territories and pathologies. The aim of this study was to assess the feasibility and validity of MRI based 4D phase contrast flow imaging for the evaluation of in-stent blood flow in 17 commonly used peripheral stents. 17 different peripheral stents were implanted into a MR compatible flow phantom. In-stent visibility, maximal velocity and flow visualization were assessed and estimates of in-stent patency obtained from 4D phase contrast flow data sets were compared to a conventional 3D contrast-enhanced magnetic resonance angiography (CE-MRA) as well as 2D PC flow measurements. In all but 3 of the tested stents time-resolved 3D particle traces could be visualized inside the stent lumen. Quality of 4D flow visualization and CE-MRA images depended on stent type and stent orientation relative to the magnetic field. Compared to the visible lumen area determined by 3D CE-MRA, estimates of lumen patency derived from 4D flow measurements were significantly higher and less dependent on stent type. A higher number of stents could be assessed for in-stent patency by 4D phase contrast flow imaging (n=14) than by 2D phase contrast flow imaging (n=10). 4D phase contrast flow imaging in peripheral vascular stents is feasible and appears advantageous over conventional 3D contrast-enhanced MR angiography and 2D phase contrast flow imaging. It allows for in-stent flow visualization and flow quantification with varying quality depending on stent type. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Reduction of Late In-Stent Stenosis in a Porcine Coronary Artery Model by Cobalt Chromium Stents with a Nanocoat of Polyphosphazene (Polyzene-F)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stampfl, Ulrike; Sommer, Christof-Matthias; Thierjung, Heidi

2008-11-15

The purpose of this study was to investigate the potential of nanoscale coating with the highly biocompatible polymer Polyzene-F (PZF), in combination with cobalt chromium and stainless steel stents, to reduce in-stent stenosis, thrombogenicity, and vessel wall injury and inflammation. One bare cobalt chromium, PZF-nanocoated stainless steel or PZF-nanocoated cobalt chromium stent was implanted in right coronary artery of 30 mini-pigs (4- or 12-week follow-up). Primary study end points were in-stent stenosis and thrombogenicity. Secondary study end points were vessel wall injury and inflammation as evaluated by microscopy and a new immunoreactivity score applying C-reactive protein (CRP), tumor-necrosis factor alphamore » (TNF{alpha}), and TGF{beta}. At 12 weeks, angiography showed a significantly lower average loss in lumen diameter (2.1% {+-} 3.05%) in PZF-nanocoated cobalt chromium stents compared with stents in the other groups (9.73% {+-} 4.93% for bare cobalt chromium stents and 9.71% {+-} 7% for PZF-nanocoated stainless steel stents; p = 0.04), which was confirmed at microscopy (neointima 40.7 {+-} 16 {mu}m in PZF-nanocoated cobalt chromium stents, 74.7 {+-} 57.6 {mu}m in bare cobalt chromium stents, and 141.5 {+-} 109 {mu}m in PZF-nanocoated stainless steel stents; p = 0.04). Injury and inflammation scores were low in all stents and were without significant differences. PZF-nanocoated cobalt chromium stents provided the highest efficacy in reducing in-stent stenosis at long-term follow-up. The PZF nanocoat proved to be biocompatible with respect to thromboresistance and inflammation. Our data suggest that its combination with cobalt chromium stents might provide an interesting passive stent platform.« less

In vitro study of role of trace amount of Cu release from Cu-bearing stainless steel targeting for reduction of in-stent restenosis.

PubMed

Ren, Ling; Xu, Lu; Feng, Jingwen; Zhang, Yang; Yang, Ke

2012-05-01

A novel 316L type Cu-bearing stainless steel was developed in present work, aiming at reducing the occurrence of the in-stent restenosis after implantations of coronary stents, through trace amount of Cu release from surface of the steel in body fluid. It was found that there was a trace amount of Cu released from the Cu-bearing steel in a simulated body fluid, with no cytotoxicity. All the in vitro experimental results proved that this Cu-bearing steel could not only inhibit the proliferation of vascular smooth muscle cells, reducing the formation of thrombosis, which are the main reasons for happening of the in-stent restenosis, but also promote the proliferation of vascular endothelial cells needed for the revascularization, showing that this novel steel is prospective to be a new material for manufacturing coronary stents with function of reducing the in-stent restenosis.

Management of Endovascular Aortic Aneurysm Complications via Retrograde Catheterization Through the Distal Stent-Graft Landing Zone.

PubMed

Zhang, Xicheng; Sun, Yuan; Chen, Zhaolei; Jing, Yuanhu; Xu, Miao

2017-08-01

A retrograde technique through the gap between the distal stent landing zone and the iliac artery wall has been applied to treat type II endoleak after endovascular aortic aneurysm repair (EVAR). In this study, we tried to investigate its efficacy in the management of type III endoleak and intraoperative accidental events. We reported 2 complications of EVAR that were difficult to treat with conventional methods. One patient had a sustained type III endoleak after EVAR, and the right renal artery was accidentally sealed by a graft stent in the other patient during the operation. Both complications were managed by the retrograde technique from the distal stent landing zone. In the first case, the endoleak was easily embolized by the retrograde catheterization technique, and in the second case, a stent was implanted in the right renal artery using the retrograde technique to restore blood flow. In some EVAR cases, the technique of retrograde catheterization through the distal stent-graft landing zone is feasible, safe, and easy to perform.

Monitoring the Wall Mechanics During Stent Deployment in a Vessel

PubMed Central

Steinert, Brian D.; Zhao, Shijia; Gu, Linxia

2012-01-01

Clinical trials have reported different restenosis rates for various stent designs1. It is speculated that stent-induced strain concentrations on the arterial wall lead to tissue injury, which initiates restenosis2-7. This hypothesis needs further investigations including better quantifications of non-uniform strain distribution on the artery following stent implantation. A non-contact surface strain measurement method for the stented artery is presented in this work. ARAMIS stereo optical surface strain measurement system uses two optical high speed cameras to capture the motion of each reference point, and resolve three dimensional strains over the deforming surface8,9. As a mesh stent is deployed into a latex vessel with a random contrasting pattern sprayed or drawn on its outer surface, the surface strain is recorded at every instant of the deformation. The calculated strain distributions can then be used to understand the local lesion response, validate the computational models, and formulate hypotheses for further in vivo study. PMID:22588353

Pulmonary vein stenosis with collateralization via esophageal varices: Long-term follow-up after successful treatment with drug-eluting stent.

PubMed

Goldberg, Jason F; Jensen, Craig L; Krishnamurthy, Rajesh; Varghese, Nidhy P; Justino, Henri

2018-01-01

We describe the long-term follow-up of a child with recurrent hemoptysis due to severe pulmonary vein stenosis decompressing via collaterals to esophageal varices. Case report SETTING: Tertiary children's hospital PATIENT: Single child through ages 2- to 11-year old INTERVENTIONS: The child underwent cutting balloon angioplasty, bare metal stenting, and implantation of a PTFE-covered stent, all of which failed rapidly. Only after placement of a paclitaxel drug eluting stent did he have prolonged relief from hemoptysis and long-term patency of the treated vein. The stents were serially dilated to keep up with somatic growth of the child, eventually culminating in the need to induce intentional stent fracture. We highlight novel transcatheter techniques to treat this vexing condition, discuss mechanisms of disease treatment and progression, and present the only patient with this rare combination of lesions to have achieved both longstanding pulmonary vein patency and resolution of esophageal varices. © 2017 Wiley Periodicals, Inc.

Risk factors for lower urinary tract infection and bacterial stent colonization in patients with a double J ureteral stent.

PubMed

Akay, Ali Ferruh; Aflay, Uğur; Gedik, Abdullah; Sahin, Hayrettin; Bircan, Mehmet Kamuran

2007-01-01

We investigated the potential risk factors for lower urinary tract infection and bacterial stent colonization in patients with double-J stents. A total of 195 double-J stents from 190 patients (95 men and 95 women, mean age 40.22 years) were examined. In all patients, prophylactic antimicrobial therapy was administered at the time of stenting. The stents and urine samples were removed aseptically and the proximal and distal tip segments of the stents were obtained. Three culture specimens were obtained from each stent segment and urine sample. Chi-square tests, odds ratio, and relative risk were used for the statistical analysis. Bacterial colonies were found in 24% (47 of 190) of the urine samples, 31% (61 of 195) of the proximal stent segments, and 34% (67 of 195) of the distal stent segments. Of the pathogens identified, Escherichia coli (34 of 47) was the most common. Diabetes mellitus (P < 0.01), chronic renal failure (P < 0.001), and pregnancy (P < 0.01) were found to be risk factors for lower urinary tract infection in patients with stents. An increased stent colonization rate was associated with implantation time, age, and female sex, but these were not statistically significant for lower urinary tract infection Diabetes mellitus, chronic renal failure, and pregnancy are associated with a higher risk of lower urinary tract infection. Therefore, patients in these categories should be monitored carefully for infectious complications.

Distinctive effects of CD34- and CD133-specific antibody-coated stents on re-endothelialization and in-stent restenosis at the early phase of vascular injury

PubMed Central

Wu, Xue; Yin, Tieying; Tian, Jie; Tang, Chaojun; Huang, Junli; Zhao, Yinping; Zhang, Xiaojuan; Deng, Xiaoyan; Fan, Yubo; Yu, Donghong; Wang, Guixue

2015-01-01

It is not clear what effects of CD34- and CD133-specific antibody-coated stents have on re-endothelialization and in-stent restenosis (ISR) at the early phase of vascular injury. This study aims at determining the capabilities of different coatings on stents (e.g. gelatin, anti-CD133 and anti-CD34 antibodies) to promote adhesion and proliferation of endothelial progenitor cells (EPCs). The in vitro study revealed that the adhesion force enabled the EPCs coated on glass slides to withstand flow-induced shear stress, so that allowing for the growth of the cells on the slides for 48 h. The in vivo experiment using a rabbit model in which the coated stents with different substrates were implanted showed that anti-CD34 and anti-CD133 antibody-coated stents markedly reduced the intima area and restenosis than bare mental stents (BMS) and gelatin-coated stents. Compared with the anti-CD34 antibody-coated stents, the time of cells adhesion was longer and earlier present in the anti-CD133 antibody-coated stents and anti-CD133 antibody-coated stents have superiority in re-endothelialization and inhibition of ISR. In conclusion, this study demonstrated that anti-CD133 antibody as a stent coating for capturing EPCs is better than anti-CD34 antibody in promoting endothelialization and reducing ISR. PMID:26813006

Automatic stent strut detection in intravascular OCT images using image processing and classification technique

NASA Astrophysics Data System (ADS)

Lu, Hong; Gargesha, Madhusudhana; Wang, Zhao; Chamie, Daniel; Attizani, Guilherme F.; Kanaya, Tomoaki; Ray, Soumya; Costa, Marco A.; Rollins, Andrew M.; Bezerra, Hiram G.; Wilson, David L.

2013-02-01

Intravascular OCT (iOCT) is an imaging modality with ideal resolution and contrast to provide accurate in vivo assessments of tissue healing following stent implantation. Our Cardiovascular Imaging Core Laboratory has served >20 international stent clinical trials with >2000 stents analyzed. Each stent requires 6-16hrs of manual analysis time and we are developing highly automated software to reduce this extreme effort. Using classification technique, physically meaningful image features, forward feature selection to limit overtraining, and leave-one-stent-out cross validation, we detected stent struts. To determine tissue coverage areas, we estimated stent "contours" by fitting detected struts and interpolation points from linearly interpolated tissue depths to a periodic cubic spline. Tissue coverage area was obtained by subtracting lumen area from the stent area. Detection was compared against manual analysis of 40 pullbacks. We obtained recall = 90+/-3% and precision = 89+/-6%. When taking struts deemed not bright enough for manual analysis into consideration, precision improved to 94+/-6%. This approached inter-observer variability (recall = 93%, precision = 96%). Differences in stent and tissue coverage areas are 0.12 +/- 0.41 mm2 and 0.09 +/- 0.42 mm2, respectively. We are developing software which will enable visualization, review, and editing of automated results, so as to provide a comprehensive stent analysis package. This should enable better and cheaper stent clinical trials, so that manufacturers can optimize the myriad of parameters (drug, coverage, bioresorbable versus metal, etc.) for stent design.

Impact of peri-stent remodeling on restenosis: a volumetric intravascular ultrasound study.

PubMed

Nakamura, M; Yock, P G; Bonneau, H N; Kitamura, K; Aizawa, T; Tamai, H; Fitzgerald, P J; Honda, Y

2001-05-01

Vessel remodeling is an important mechanism of late lumen loss after nonstent coronary interventions. However, its impact on in-stent restenosis has not been systematically investigated. Serial volumetric intravascular ultrasound analyses (poststent and follow-up) were performed in 55 lesions treated with a balloon-expandable stent (ACS MultiLink) using standard stent deployment techniques. The vessel volume (VV), lumen volume (LV), and volume bordered by the stent (SV) were measured using Simpson's method. The volume of plaque and neointima outside the stent (peri-stent volume, PSV) and volume of neointima within the stent (intrastent volume) were also measured. The change of each parameter during the follow-up period (follow-up minus poststent) was calculated and then divided by SV to normalize these values (designated as percent change [%]). As expected, %PSV directly correlated with %VV (P<0.0001, r=0.935), with no significant SV. A highly significant inverse correlation was seen between %PSV and the percent change of intrastent volume (P<0.0001, r=0.517). Consequently, %LV significantly correlated with peri-stent remodeling, as measured by %VV (P<0.0001, r=0.602). Positive remodeling of the vessel exterior to a coronary stent occurs to a variable degree after stent implantation. There is a distinct trade-off between positive remodeling and in-stent hyperplasia: in segments in which the degree of peri-stent remodeling is less, intrastent neointimal proliferation is greater and accompanied by more significant late lumen loss.

Rotational atherectomy before paclitaxel-eluting stent implantation in complex calcified coronary lesions: Two-year clinical outcome of the randomized ROTAXUS trial.

PubMed

de Waha, Suzanne; Allali, Abdelhakim; Büttner, Heinz-Joachim; Toelg, Ralph; Geist, Volker; Neumann, Franz-Josef; Khattab, Ahmed A; Richardt, Gert; Abdel-Wahab, Mohamed

2016-03-01

In the randomized ROTAXUS trial, routine lesion preparation of complex calcified coronary lesions using rotational atherectomy (RA) prior to paclitaxel-eluting stent implantation did not reduce the primary endpoint of angiographic late lumen loss at 9 months compared to stenting without RA. So far, no long-term data of prospective head-to-head comparisons between both treatment strategies have been reported. ROTAXUS randomly assigned patients with complex calcified coronary lesions to RA followed by stenting (n = 120) or stenting without RA (n = 120). The primary endpoint of the current analysis was the occurrence of major adverse cardiac events (MACE) at 2-year follow-up defined as the composite of death, myocardial infarction, and target vessel revascularization (TVR). At 2 years, MACE occurred in 32 patients in the RA group and 37 patients in the standard therapy group (29.4% vs. 34.3%, P = 0.47). The rates of death (8.3% vs. 7.4%, P = 1.00), myocardial infarction (8.3% vs. 6.5%, P = 0.80), target lesion revascularization (TLR, 13.8% vs. 16.7%, P = 0.58), and TVR (19.3% vs. 22.2%, P = 0.62) were similar in both groups. Despite high rates of initial angiographic success, nearly one third of patients enrolled in ROTAXUS experienced MACE within 2-year follow-up, with no differences between patients treated with or without RA. © 2015 Wiley Periodicals, Inc.

RNA-Eluting Surfaces for the Modulation of Gene Expression as A Novel Stent Concept

PubMed Central

Koenig, Olivia; Zengerle, Diane; Perle, Nadja; Hossfeld, Susanne; Neumann, Bernd; Behring, Andreas; Avci-Adali, Meltem; Walker, Tobias; Schlensak, Christian; Wendel, Hans Peter; Nolte, Andrea

2017-01-01

Presently, a new era of drug-eluting stents is continuing to improve late adverse effects such as thrombosis after coronary stent implantation in atherosclerotic vessels. The application of gene expression–modulating stents releasing specific small interfering RNAs (siRNAs) or messenger RNAs (mRNAs) to the vascular wall might have the potential to improve the regeneration of the vessel wall and to inhibit adverse effects as a new promising therapeutic strategy. Different poly (lactic-co-glycolic acid) (PLGA) resomers for their ability as an siRNA delivery carrier against intercellular adhesion molecule (ICAM)-1 with a depot effect were tested. Biodegradability, hemocompatibility, and high cell viability were found in all PLGAs. We generated PLGA coatings with incorporated siRNA that were able to transfect EA.hy926 and human vascular endothelial cells. Transfected EA.hy926 showed significant siICAM-1 knockdown. Furthermore, co-transfection of siRNA and enhanced green fluorescent protein (eGFP) mRNA led to the expression of eGFP as well as to the siRNA transfection. Using our PLGA and siRNA multilayers, we reached high transfection efficiencies in EA.hy926 cells until day six and long-lasting transfection until day 20. Our results indicate that siRNA and mRNA nanoparticles incorporated in PLGA films have the potential for the modulation of gene expression after stent implantation to achieve accelerated regeneration of endothelial cells and to reduce the risk of restenosis. PMID:28208634

Impact of coronary artery stent edge dissections on long-term clinical outcome in patients with acute coronary syndrome: an optical coherence tomography study.

PubMed

Bouki, Konstantina P; Sakkali, Eleni; Toutouzas, Konstantinos; Vlad, Delia; Barmperis, Dimitrios; Phychari, Stavroula; Riga, Maria; Apostolou, Thomas; Stefanadis, Christodoulos

2015-08-01

The purpose of the present study was to assess the incidence, predictors and long term prognosis of stent edge dissections identified by (OCT) after the implantation of bare metal (BMS) and drug eluting stents (DES). We studied 74 patients who underwent percutaneous coronary intervention (PCI) because of an acute coronary syndrome. Edge dissections were found in 29 of 74 patients (39.1%). Independent predictors of edge dissections were: the presence of ST-elevation myocardial infarction (STEMI) (P = 0.005, odds ratio 11.78; 95% Cl 2.06-67.10), the small reference lumen diameter (P = 0.009, odds ratio 0.11; 95% Cl 0.02-0.58) and the short stents implanted (P = 0.013, odds ratio 0.83; 95% Cl 0.72-0.96). During a follow-up period of 25.6 ± 9.4 months 11 patients presented with at least one major adverse cardiac event. Event free survival was significantly decreased in patients with edge dissection with a flap thickness >0.31 mm compared to patients with thinner flap or without any dissection (P < 0.001). OCT frequently detects edge dissections, usually related to STEMI presentation and to PCI technique. Deep vessel wall injury at stent edges with a dissection flap thickness more than 0.31mm carries an adverse clinical impact on long-term clinical outcome. © 2015 Wiley Periodicals, Inc.

Secondary flow structures in the presence of Type-IV stent fractures through a bent tube model for curved arteries: Effect of circulation thresholding

NASA Astrophysics Data System (ADS)

Hussain, Shadman; Bulusu, Kartik V.; Plesniak, Michael W.

2013-11-01

A common treatment for atherosclerosis is the opening of narrowed arteries resulting from obstructive lesions by angioplasty and stent implantation to restore unrestricted blood flow. ``Type-IV'' stent fractures involve complete transverse, linear fracture of stent struts, along with displacement of the stent fragments. Experimental data pertaining to secondary flows in the presence of stents that underwent ``Type-IV'' fractures in a bent artery model under physiological inflow conditions were obtained through a two-component, two-dimensional (2C-2D) PIV technique. Concomitant stent-induced flow perturbations result in secondary flow structures with complex, multi-scale morphologies and varying size-strength characteristics. Ultimately, these flow structures may have a role to play in restenosis and progression of atherosclerotic plaque. Vortex circulation thresholds were established with the goal of resolving and tracking iso-circulation secondary flow vortical structures and their morphological changes. This allowed for a parametric evaluation and quantitative representation of secondary flow structures undergoing deformation and spatial reorganization. Supported by NSF Grant No. CBET- 0828903 and GW Center for Biomimetics and Bioinspired Engineering.

Stent manufacturing using cobalt chromium molybdenum (CoCrMo) by selective laser melting technology

NASA Astrophysics Data System (ADS)

Omar, Mohd Asnawi; Baharudin, BT-HT; Sulaiman, S.

2017-12-01

This paper reviews the capabilities of additive manufacturing (AM) technology and the use of Cobalt super alloy stent fabrication by looking at the dimensional accuracy and mechanical properties of the stent. Current conventional process exhibit many processes which affect the supply chain, costing, and post processing. By alternatively switching to AM, the step of production can be minimized and thus customization of stent can be carried out according to patients need. The proposed methodology is a perfect choice as surgeons need to have an accurate size during stent implantation. It also is able to reduce time-to-market delivery in a matter of hours and from days. The suggested stent model was taken from the third party vendor and flow optimization was carried out using Materialise Magics TM software. By using SLM125TM printer, the printing parameters such as Energy Density (DE), Laser Power (PL), Scanning Speed (SS) and Hatching Distance (DH) was used to print the stent. The properties of the finished product, such as strength, surface finish and orientation was investigated.

Recent Advances in Drug Eluting Stents

PubMed Central

Puranik, Amey S.; Dawson, Eileen R.; Peppas, Nicholas A.

2013-01-01

One of the most common medical interventions to reopen an occluded vessel is the implantation of a coronary stent. While this method of treatment is effective initially, restenosis, or the re-narrowing of the artery frequently occurs largely due to neointimal hyperplasia of smooth muscle cells. Drug eluting stents were developed in order to provide local, site-specific, controlled release of drugs that can inhibit neointima formation. By implementing a controlled release delivery system it may be possible to control the time release of the pharmacological factors and thus be able to bypass some of the critical events associated with stent hyperplasia and prevent the need for subsequent intervention. However, since the advent of first-generation drug eluting stents, long-term adverse effects have raised concerns regarding their safety. These limitations in safety and efficacy have triggered considerable research in developing biodegradable stents and more potent drug delivery systems. In this review, we shed light on the current state-of-the-art in drug eluting stents, problems related to them and highlight some of the ongoing research in this area. PMID:23117022

Plaque components affect wall stress in stented human carotid artery: A numerical study

NASA Astrophysics Data System (ADS)

Fan, Zhen-Min; Liu, Xiao; Du, Cheng-Fei; Sun, An-Qiang; Zhang, Nan; Fan, Zhan-Ming; Fan, Yu-Bo; Deng, Xiao-Yan

2016-12-01

Carotid artery stenting presents challenges of in-stent restenosis and late thrombosis, which are caused primarily by alterations in the mechanical environment of the artery after stent implantation. The present study constructed patient-specific carotid arterial bifurcation models with lipid pools and calcified components based on magnetic resonance imaging. We numerically analyzed the effects of multicomponent plaques on the distributions of von Mises stresses (VMSs) in the patient-specific models after stenting. The results showed that when a stent was deployed, the large soft lipid pool in atherosclerotic plaques cushioned the host artery and reduced the stress within the arterial wall; however, this resulted in a sharp increase of VMS in the fibrous cap. When compared with the lipid pool, the presence of the calcified components led to slightly increased stresses on the luminal surface. However, when a calcification was located close to the luminal surface of the host artery and the stenosis, the local VMS was elevated. Overall, compared with calcified components, large lipid pools severely damaged the host artery after stenting. Furthermore, damage due to the calcified component may depend on location.

Long-term results of a sirolimus-eluting stent with biodegradable polymer (RAPSTROM™) in de novo coronary stenoses.

PubMed

Figini, Filippo; Manjunath, Chaman Nadish; Srinivas, Balaji Chandra; Sadananda, Kanvar Sarat; Sreedharan, Madhu; Fischer, Louie; Pillai, Ramakrishna; Varghese, Kiron; Gopal, Ajay K; Nagesh, Chamarajnagar Mahadevappa; Sheiban, Imad

2017-10-07

To report long-term results of a novel sirolimus-eluting stent with biodegradable polymer BACKGROUND: Newer generation drug-eluting stents are characterized by thin struts, improved platform design and highly biocompatible polymer carrying the antiproliferative drug. The RapstromTM stent, sharing these features, showed promising outcomes in preclinical models and in a first-in-man trial. The present study is a multicenter, non-randomized post-market registry, including patients with de novo coronary artery disease treated with implantation of one or more Rapstrom stents. Primary endpoint of the study was the rate of major adverse cardiac events (MACE) at three-year follow-up. 1073 patients were enrolled, with a high prevalence of diabetes (35%) and acute coronary syndrome at presentation (82%); at three-year follow up, MACE rate was 14.8%, with a low incidence of definite or probable stent thrombosis (0.75%). These data confirm the good clinical performance of the Rapstrom stent, supporting the concept that the combination of thin struts and biodegradable polymer is associated with positive clinical outcomes. Copyright © 2017 Elsevier Inc. All rights reserved.

A new approach to endoscopic treatment of tumors of the esophagogastric junction with individually designed self-expanding metal stents

PubMed Central

Aymaz, Serhat; Dormann, Arno J

2008-01-01

The incidence of adenocarcinoma of the esophago-gastric junction is constantly increasing. Curative treatment is no longer possible at the time of diagnosis in more than 50% of patients with esophageal carcinoma, and palliative treatment focusing on eliminating dysphagia is required. Endoscopic therapy with stent implantation is an established method of achieving this. It can be carried out quickly, with a low rate of early complications, and leads to fast symptomatic improvement, assessed using the dysphagia score. The relatively high rate of late complications such as stent migration, hemorrhage, and gastroesophageal mucosal prolapse has led to recent debate on the role of metal stents in palliative therapy. We present here a new type of stent design for transcardial application, which is intended to prevent bleeding due to mechanical mucosal lesions caused by the distal end of the stent extending into the stomach. The further intention of this case report is to force the discussion on individually designed nitinol stents in special anatomic conditions. PMID:18609720

Hematopoietic stem cell capture and directional differentiation into vascular endothelial cells for metal stent-coated chitosan/hyaluronic acid loading CD133 antibody.

PubMed

Zhang, Shixuan; Zhang, Fan; Feng, Bo; Fan, Qingyu; Yang, Feng; Shang, Debin; Sui, Jinghan; Zhao, Hong

2015-03-01

A series of metal stents coated with chitosan/hyaluronic acid (CS/HA) loading antibodies by electrostatic self-assembled method were prepared, and the types of cells captured by antibodies and their differentiation in vascular endothelial cells (ECs) evaluated by molecular biology and scanning electron microscope. The results showed that CD133 stent can selectively capture hematopoietic stem cells (HSC),which directionally differentiate into vascular ECs in peripheral blood by (CS/HA) induction, and simultaneously inhibit migration and proliferation of immune cells and vascular smooth muscle cells (MCs). CD34 stent can capture HSC, hematopoietic progenitor cells that differentiate into vascular ECs and immune cells, promoting smooth MCs growth, leading to thrombosis, inflammation, and rejection. CD133 stent can be implanted into miniature pig heart coronary and can repair vascular damage by capturing own HSC, thus contributing to the rapid natural vascular repair, avoiding inflammation and rejection, thrombosis and restenosis. These studies demonstrated that CD133 stent of HSC capture will be an ideal coated metal stent providing a new therapeutic approach for cardiovascular and cerebrovascular disease.

Food impaction after expandable metal stent placement: experience in 1,360 patients with esophageal and upper gastrointestinal tract obstruction.

PubMed

Song, Min; Song, Ho-Young; Kim, Jin Hyoung; Park, Jung-Hoon; Jung, Hwoon-Yong; Kim, Jong-Hoon; Kim, Sung-Bae

2011-09-01

To retrospectively evaluate the incidence, predictive factors, and interventional management of food impaction after expandable metallic stent placement in patients with obstruction of the esophagus or upper gastrointestinal tract caused by benign or malignant disease. Between March 1993 and March 2010, 1,360 patients (1,029 men, 331 women; age range, 21-89 y; mean age, 61 y) underwent fluoroscopically guided stent placement for dysphagia caused by esophageal or gastrointestinal tract strictures. Five types of covered expandable metal stents were used, including four types of esophageal stents (types A-D) and one type of gastroduodenal stent (type E), with types A, B, C, D, and E stents used in 180, 60, 90, 432, and 598 patients, respectively. Multivariate analysis was performed to evaluate factors predictive of food impaction. Food impaction occurred in 41 of 1,360 patients (3.0%). The food impaction rates for types A, B, C, D, and E stents were 0.6%, 1.7%, 1.1%, 3.2%, and 4.0%, respectively. Multivariate analysis showed that stent length was an independent predictor of food impaction (odds ratio, 0.839; P = .012). Of the 41 patients with food impaction, 23 underwent endoscopic management, 12 underwent fluoroscopically guided management, and six did not require management because impacted food spontaneously passed through the stent. The overall food impaction rate was 3.0%, with multiple logistic regression analysis showing that shorter stent length was the only significant predictor of food impaction. Food impaction can be managed by endoscopic or fluoroscopically guided removal or placement of a second stent. Copyright © 2011 SIR. Published by Elsevier Inc. All rights reserved.

Heparin-bonded, expanded polytetrafluoroethylene-lined stent graft in the treatment of femoropopliteal artery disease: 1-year results of the VIPER (Viabahn Endoprosthesis with Heparin Bioactive Surface in the Treatment of Superficial Femoral Artery Obstructive Disease) trial.

PubMed

Saxon, Richard R; Chervu, Arun; Jones, Paul A; Bajwa, Tanvir K; Gable, Dennis R; Soukas, Peter A; Begg, Richard J; Adams, John G; Ansel, Gary M; Schneider, Darren B; Eichler, Charles M; Rush, Michael J

2013-02-01

To evaluate the performance of a heparin-bonded, expanded polytetrafluoroethylene (ePTFE)-lined nitinol endoprosthesis in the treatment of long-segment occlusive disease of the femoropopliteal artery (FPA) and to identify factors associated with loss of patency. In a single-arm, prospective, 11-center study (VIPER [Gore Viabahn Endoprosthesis with Heparin Bioactive Surface in the Treatment of Superficial Femoral Artery Obstructive Disease] trial), 119 limbs (113 patients; 69 men; mean age, 67 y), including 88 with Rutherford category 3-5 disease and 72 with Inter-Society Consensus for the Management of Peripheral Arterial Disease (TASC II) C or D lesions of the FPA, underwent stent graft implantation. The mean lesion length was 19 cm; 56% of lesions were occlusions. Follow-up evaluations included color duplex ultrasonography in all patients, with patency defined as a peak systolic velocity ratio< 2.5. At 12 months, Rutherford category and ankle-brachial index (ABI) were significantly improved (mean category improvement, 2.4; ABI increased from 0.6±0.2 to 0.9±0.19; P<.0001). Primary and secondary patency rates were 73% and 92%. The primary patency for devices oversized<20% at the proximal landing zone was 88%, whereas the primary patency for devices oversized by>20% was 70% (P = .047). Primary patency was not significantly affected by device diameter (5 vs 6 vs 7 mm) or lesion length (≤20 cm vs>20 cm). The 30-day major adverse event rate was 0.8%. The heparin-bonded, ePTFE/nitinol stent graft provided clinical improvement and a primary patency rate of 73% at 1 year in the treatment of long-segment FPA disease. Careful sizing of the device relative to vessel landing zones is essential for achieving optimal outcomes. Copyright © 2013 SIR. Published by Elsevier Inc. All rights reserved.

Development of a dynamic in vitro model of a stented blood vessel to evaluate the effects of stent strut material selection and surface coating on smooth muscle cell response

NASA Astrophysics Data System (ADS)

Winn, Bradley Huegh

Cardiovascular disease is the leading cause of mortality in The United States and Europe, accounting for approximately half of all deaths. The most common form of cardiovascular disease is atherosclerosis, which is characterized by the formation of fatty atheromatous plaques that can grow to occlude the vessel lumen, thus causing ischemia distal to the occlusion. This is commonly treated using balloon angioplasty, which is usually done in conjunction with the deployment of a stent. Stent deployment helps hold the vessel open following the local injury caused by balloon inflation and prevents elastic recoil and subsequent negative remodeling. Stenting has been shown to significantly reduce restenosis rates from approximately 20-50% without a stent to about 10-30% with stent deployment. However, restenosis still remains the main cause of long-term stent failure. In basic terms, a balloon angioplasty procedure is a forceful displacement of an atherosclerotic lesion serving to widen the vessel lumen to increase blood flow. This procedure causes stretching of the vessel wall, tears in the atherosclerotic plaques, and general damage to the vessel in turn signaling a complex cascade of thrombosis, inflammation, intimal thickening, and vascular remodeling. Stent deployment also further complicates the immunological response by triggering a foreign body response from the implantation of a biomaterial into the body. When performing an angioplasty procedure, particularly in conjunction with stent deployment, a certain degree of vascular injury is inevitable. However, the initial injury can be further complicated by the body's local reaction to the implanted biomaterial, the severity of which can ultimately dictate the degree of restenosis and subsequently affect procedural success. The proliferative response of VSMCs to the various afore mentioned stimuli results in the formation of often copious amounts of neointimal tissue, generally known as intimal hyperplasia. The formation of this new tissue, primarily consisting of VSMCs of the synthetic phenotype and their subsequent extracellular matrix, is the sole causation of in-stent restenosis since the stent serves to prevent elastic recoil and negative remodeling. This doctoral research program is focused on endovascular stent biomaterials science and engineering. Overall, this doctoral project is founded on the hypothesis that smooth muscle cell hyperplasia, as an important causative factor for vascular restenosis following endovascular stent deployment, is triggered by the various effects of stent strut contact on the vessel wall including contact forces and material biocompatibility. In this program, a dynamic in vitro model of a stented blood vessel aimed at evaluating the effect of stent strut material selection, and surface coating on smooth muscle cell response was developed. The in vitro stented artery model was validated through the proliferation of VSMC in contact with stent struts. Additionally, it was demonstrated that, with respect to known biocompatible materials such as Nitinol and 316L stainless steel, DNA synthesis and alpha-actin expression, as indicators of VSMC phenotype, are independent of stent material composition. Furthermore, hydroxyapatite was shown to be a biocompatible stent surface coating with acceptable post-strain integrity. This coating was shown in a feasibility study to be capable of serving as a favorable drug delivery platform able to reliably deliver locally therapeutic doses of bisphosphonates, such as alendronate, to control VSMC proliferation in an in vitro model of a stented blood vessel. This stent coating/drug combination may be effective for reducing restenosis as a result of VSMC hyperplasia in vivo.

Longitudinal Deformation of Distal Edge in a New-Generation Stent Caused by Guidewire Entrapment

PubMed Central

Taleb, Adam; Parikh, Gaurav

2018-01-01

Longitudinal stent deformation, described in some older stent geometries, prompted design modifications such as reinforcing struts on the proximal end. However, distal edges of stents—also subject to longitudinal force—have not been reinforced. We report a case of guidewire entrapment that deformed the distal edge of a new-generation stent during percutaneous coronary intervention, and we describe our efforts to restore the stent to its initial length. This case highlights the risk of manipulating equipment beyond the position of a newly deployed stent, the ongoing potential for deformation of distal edges in newer stent platforms, and the advisability of treating distal lesions before proximal ones. PMID:29556153

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sakamoto, Susumu, E-mail: susumu1029@gmail.com; Kikuchi, Naoshi; Ichikawa, Atsuo

Despite the wide use of everolimus as an antineoplastic coating agent for coronary stents to reduce the rate of restenosis, little is known about the health hazards of everolimus-eluting stents (EES). We describe a case of pneumonitis that developed 2 months after EES implantation for angina. Lung pathology demonstrated an organizing pneumonia pattern that responded to corticosteroid therapy. Although the efficacy of EES for ischemic heart disease is well established, EES carries a risk of pneumonitis.

Two-Year Clinical Outcomes of Newer-Generation Drug-Eluting Stent Implantation Following Rotational Atherectomy for Heavily Calcified Lesions.

PubMed

Jinnouchi, Hiroyuki; Kuramitsu, Shoichi; Shinozaki, Tomohiro; Kobayashi, Yohei; Hiromasa, Takashi; Morinaga, Takashi; Mazaki, Toru; Sakakura, Kenichi; Soga, Yoshimitsu; Hyodo, Makoto; Shirai, Shinichi; Ando, Kenji

2015-01-01

Clinical outcomes of implantation of the newer-generation drug-eluting stent (DES) following rotational atherectomy for heavily calcified lesions remain unclear in the real-world setting. We enrolled 252 consecutive patients (273 lesions) treated with newer-generation DES following rotational atherectomy. The primary endpoint was the cumulative 2-year incidence of major adverse cardiovascular events (MACE), defined as cardiac death, myocardial infarction, clinically-driven target lesion revascularization, and definite stent thrombosis. Complete clinical follow-up information at 2-year was obtained for all patients. The mean age was 73.2±9.0 years and 155 patients (61.5%) were male. Cumulative 2-year incidence of MACE (cardiac death, myocardial infarction, clinically-driven target lesion revascularization and definite stent thrombosis) was 20.3% (7.0%, 2.1%, 18.1% and 2.1%, respectively). Predictors of MACE were presenting with acute coronary syndrome (hazard ratio [HR]: 3.80, 95% confidence interval [CI]: 1.29-11.2, P=0.02), hemodialysis (HR: 1.93, 95% CI: 1.04-3.56, P=0.04) and previous coronary artery bypass graft (HR: 2.26, 95% CI: 1.02-5.00, P=0.045). PCI for calcified lesions requiring rotational atherectomy is still challenging even in the era of newer-generation DES.

Multifaceted prospects of nanocomposites for cardiovascular grafts and stents

PubMed Central

Vellayappan, Muthu Vignesh; Balaji, Arunpandian; Subramanian, Aruna Priyadarshini; John, Agnes Aruna; Jaganathan, Saravana Kumar; Murugesan, Selvakumar; Supriyanto, Eko; Yusof, Mustafa

2015-01-01

Cardiovascular disease is the leading cause of death across the globe. The use of synthetic materials is indispensable in the treatment of cardiovascular disease. Major drawbacks related to the use of biomaterials are their mechanical properties and biocompatibility, and these have to be circumvented before promoting the material to the market or clinical setting. Revolutionary advancements in nanotechnology have introduced a novel class of materials called nanocomposites which have superior properties for biomedical applications. Recently, there has been a widespread recognition of the nanocomposites utilizing polyhedral oligomeric silsesquioxane, bacterial cellulose, silk fibroin, iron oxide magnetic nanoparticles, and carbon nanotubes in cardiovascular grafts and stents. The unique characteristics of these nanocomposites have led to the development of a wide range of nanostructured copolymers with appreciably enhanced properties, such as improved mechanical, chemical, and physical characteristics suitable for cardiovascular implants. The incorporation of advanced nanocomposite materials in cardiovascular grafts and stents improves hemocompatibility, enhances antithrombogenicity, improves mechanical and surface properties, and decreases the microbial response to the cardiovascular implants. A thorough attempt is made to summarize the various applications of nanocomposites for cardiovascular graft and stent applications. This review will highlight the recent advances in nanocomposites and also address the need of future research in promoting nanocomposites as plausible candidates in a campaign against cardiovascular disease. PMID:25897223

In Situ Fracture of Stents Implanted for Relief of Pulmonary Arterial Stenosis in Patients with Congenitally Malformed Hearts

PubMed Central

McElhinney, Doff B.; Bergersen, Lisa; Marshall, Audrey C.

2014-01-01

Background One of the most common uses of stents in patients with congenitally malformed hearts is treatment of pulmonary arterial stenosis. Although there are reports of fractured pulmonary arterial stents, little is known about the risk factors for, and implications of, such fractures. Methods We reviewed angiograms to identify fractures in stents previously inserted to relieve stenoses in pulmonary arteries from 1990 through 2001 in patients who also underwent follow-up catheterization at least 3 years after placement of the stent. We undertook matched cohort analysis, matching a ratio of 2 fractured to 1 unfractured stent. Results Overall, 166 stents meeting the criterions of our study had been placed in 120 patients. We identified fractures in 35 stents (21%) in 29 patients. All fractured stents were in the central pulmonary arteries, 24 (69%) in the central part of the right pulmonary artery, and all were complete axial fractures, or complex fractures along at least 2 planes. Stent-related factors associated with increased risk of fracture identified by multivariable logistic regression included placement in close apposition to the ascending aorta (p = 0.001), and a larger expanded diameter (p = 0.002). There was obstruction across 28 of 35 fractured stents, which was severe in 11. We re-stented 21 of the fractured stents, and recurrent fracture was later diagnosed in 3 of these. A fragment of the fractured stent embolized distally in 2 patients, without clinically important effects. Conclusions In situ fracture of pulmonary arterial stents is relatively common, and in most cases is related to compression by the aorta. There is usually recurrent obstruction across the fractured stent, but fractured stents rarely embolize, and are not associated with other significant complications. PMID:18559137

Optimization of Electropolishing on NiTi Alloy Stents and Its Influence on Corrosion Behavior.

PubMed

Kim, Jinwoo; Park, Jun-Kyu; Kim, Han Ki; Unnithan, Afeesh Rajan; Kim, Cheol Sang; Park, Chan Hee

2017-04-01

Nitinol or NiTi alloys are well-known as an attractive biomedical material due to their unique properties such as the shape memory effect, super-elasticity and biocompatibility. These characteristics enable them to be best candidates for implant materials such as stent. One of the major factors that strongly affect the performance of nitinol stent is its unique surface properties. In this study, the influence of electropolishing on nitinol stents and its corrosion behavior were observed. Electropolishing is an effective method for surface treatment, which not only controls the surface state but also helps to produce uniform surface layers. Therefore, to improve the surface quality of nitinol stents, we conducted an electropolishing under various conditions from 30–40 V and 10–30 s as a post heat treatment for nitinol stent manufacturing process. In order to find the optimal surface state of NiTi stents, various electropolished samples were explored using various characterization techniques. Furthermore, the potentiodynamic polarization tests were also performed to determine the corrosion resistance. The electropolished nitinol stents under the condition of 40 V for 10 s exhibited the best corrosion performance as well as surface quality.

Surface Conditioning of Cardiovascular 316L Stainless Steel Stents: a Review

NASA Astrophysics Data System (ADS)

Navarro, Lucila; Luna, Julio; Rintoul, Ignacio

2017-07-01

Cardiovascular disease is the leading cause of death worldwide and 90% of coronary interventions consists in stenting procedures. Most of the implanted stents are made of AISI 316L stainless steel (SS). Excellent mechanical properties, biocompatibility, corrosion resistance, workability and statistically demonstrated medical efficiency are the reasons for the preference of 316L SS over any other material for stent manufacture. However, patients receiving 316L SS bare stents are reported with 15-20% of restenosis probability. The decrease of the restenosis probability is the driving force for a number of strategies for surface conditioning of 316L SS stents. This review reports the latest advances in coating, passivation and the generation of controlled topographies as strategies for increasing the corrosion resistance and reducing the ion release and restenosis probability on 316L SS stents. Undoubtedly, the future of technique is related to the elimination of interfaces with abrupt change of properties, the elimination of molecules and any other phase somehow linked to the metal substrate. And leaving the physical, chemical and topographical smart modification of the outer part of the 316L SS stent for enhancing the biocompatiblization with endothelial tissues.