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.

J-tube technique for double-j stent insertion during laparoscopic upper urinary tract surgical procedures.

PubMed

Kim, Hyung Suk; Lee, Byung Ki; Jung, Jin-Woo; Lee, Jung Keun; Byun, Seok-Soo; Lee, Sang Eun; Jeong, Chang Wook

2014-11-01

Double-J stent insertion has been generally performed during laparoscopic upper urinary tract (UUT) surgical procedures to prevent transient urinary tract obstruction and postoperative flank pain from ureteral edema and blood clots. Several restrictive conditions that make this procedure difficult and time consuming, however, include the coiled distal ends of the flexible Double-J stent and the limited bending angle of the laparoscopic instruments. To overcome these limitations, we devised a Double-J stent insertion method using the new J-tube technique. Between July 2011 and May 2013, Double-J stents were inserted using the J-tube technique in 33 patients who underwent a laparoscopic UUT surgical procedure by a single surgeon. The mean stent placement time was 4.8±2.7 minutes, and there were no intraoperative complications. In conclusion, the J-tube technique is a safe and time-saving method for Double-J stent insertion during laparoscopic surgical procedures.

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.

Utility of the balloon-overtube-assisted modified over-the-wire stenting technique to treat post-sleeve gastrectomy complications.

PubMed

Ponte, Ana; Pinho, Rolando; Proença, Luísa; Silva, Joana; Rodrigues, Jaime; Sousa, Mafalda; Silva, João Carlos; Carvalho, João

2017-06-16

To describe a modified technique of deployment of stents using the overtube developed for balloon-assisted enteroscopy in post-sleeve gastrectomy (SG) complications. Between January 2010 and December 2015, all patients submitted to an endoscopic stenting procedure to treat a post-SG stenosis or leakage were retrospectively collected. Procedures from patients in which the stent was deployed using the balloon-overtube-assisted modified over-the-wire (OTW) stenting technique were described. The technical success, corresponding to proper placement of the stent in the stomach resulting in exclusion of the SG leak or the stenosis, was evaluated. Complications related to stenting were also reported. Five procedures were included to treat 2 staple line leaks and 3 stenoses. Two types of stents were used, including a fully covered self-expandable metal stent designed for the SG anatomy (Hanarostent, ECBB-30-240-090; M.I. Tech, Co., Ltd, Seoul, South Korea) in 4 procedures and a biodegradable stent (BD stent 019-10A-25/20/25-080, SX-ELLA, Hradec Kralove, Czech Republic) in the remaining procedure. In all cases, an overtube was advanced with the endoscope through the SG to the duodenum. After placement of the guidewire and removal of the endoscope, the stent was easily advanced through the overtube. The overtube was pulled back and the stent was successfully deployed under fluoroscopic guidance. Technical success was achieved in all patients. The adoption of a modified technique of deployment of OTW stents using an overtube may represent an effective option in the approach of SG complications.

Utility of the balloon-overtube-assisted modified over-the-wire stenting technique to treat post-sleeve gastrectomy complications

PubMed Central

Ponte, Ana; Pinho, Rolando; Proença, Luísa; Silva, Joana; Rodrigues, Jaime; Sousa, Mafalda; Silva, João Carlos; Carvalho, João

2017-01-01

AIM To describe a modified technique of deployment of stents using the overtube developed for balloon-assisted enteroscopy in post-sleeve gastrectomy (SG) complications. METHODS Between January 2010 and December 2015, all patients submitted to an endoscopic stenting procedure to treat a post-SG stenosis or leakage were retrospectively collected. Procedures from patients in which the stent was deployed using the balloon-overtube-assisted modified over-the-wire (OTW) stenting technique were described. The technical success, corresponding to proper placement of the stent in the stomach resulting in exclusion of the SG leak or the stenosis, was evaluated. Complications related to stenting were also reported. RESULTS Five procedures were included to treat 2 staple line leaks and 3 stenoses. Two types of stents were used, including a fully covered self-expandable metal stent designed for the SG anatomy (Hanarostent, ECBB-30-240-090; M.I. Tech, Co., Ltd, Seoul, South Korea) in 4 procedures and a biodegradable stent (BD stent 019-10A-25/20/25-080, SX-ELLA, Hradec Kralove, Czech Republic) in the remaining procedure. In all cases, an overtube was advanced with the endoscope through the SG to the duodenum. After placement of the guidewire and removal of the endoscope, the stent was easily advanced through the overtube. The overtube was pulled back and the stent was successfully deployed under fluoroscopic guidance. Technical success was achieved in all patients. CONCLUSION The adoption of a modified technique of deployment of OTW stents using an overtube may represent an effective option in the approach of SG complications. PMID:28690770

The Need For Dedicated Bifurcation Stents: A Critical Analysis

PubMed Central

Lesiak, Maciej

2016-01-01

There is growing evidence that optimally performed two-stent techniques may provide similar or better results compared with the simple techniques for bifurcation lesions, with an observed trend towards improvements in clinical and/or angiographic outcomes with a two-stent strategy. Yet, provisional stenting remains the treatment of choice. Here, the author discusses the evidence – and controversies – concerning when and how to use complex techniques. PMID:29588719

Y stenting assisted coiling using a new low profile visible intraluminal support device for wide necked basilar tip aneurysms: a technical report.

PubMed

Conrad, Marcelo D; Brasiliense, Leonardo B C; Richie, Alexa N; Hanel, Ricardo A

2014-05-01

Many endovascular techniques have been described in recent years for the management of wide necked aneurysms. The Y stent assisted technique has been generally used for coil embolization of wide necked bifurcation aneurysms. This technique was first described for the treatment of basilar tip aneurysms in combination with several different devices, demonstrating encouraging results. We report the results of the first two cases of wide necked basilar tip aneurysms treated with Y stent assisted coil embolization using a new low profile visible intraluminal stent (LVIS Jr; MicroVention, Tustin, California, USA) delivered through a 0.017 inch microcatheter. We also reviewed the literature comparing other endovascular techniques (coiling alone, stent assisted coiling, and Y stent assisted coiling) for wide necked aneurysms. The LVIS Jr device offers a new option for the treatment of these challenging lesions, with clear advantages over currently available intracranial stents. Larger series and long term results are needed to confirm the applicability and durability of this technique/technology.

Classification and outcomes of extended arch repair for acute Type A aortic dissection: a systematic review and meta-analysis.

PubMed

Smith, Holly N; Boodhwani, Munir; Ouzounian, Maral; Saczkowski, Richard; Gregory, Alexander J; Herget, Eric J; Appoo, Jehangir J

2017-03-01

Distal extent of repair in patients undergoing surgery for acute Type A aortic dissection (ATAAD) is controversial. Emerging hybrid techniques involving open and endovascular surgery have been reported in small numbers by select individual centres. A systematic review and meta-analysis was performed to investigate the outcomes following extended arch repair for ATAAD. A classification system is proposed of the different techniques to facilitate discussion and further investigation. Using Ovid MEDLINE, 38 studies were identified reporting outcomes for 2140 patients. Studies were categorized into four groups on the basis of extent of surgical aortic resection and the method of descending thoracic aortic stent graft deployment; during circulatory arrest (frozen stented elephant trunk) or with normothermic perfusion and use of fluoroscopy (warm stent graft): (I) surgical total arch replacement, (II) total arch and frozen stented elephant trunk, (III) hemiarch and frozen stented elephant trunk and (IV) total arch and warm stent graft. Perioperative event rates were obtained for each of the four groups and the entire cohort using pooled summary estimates. Linearized rates of late mortality and reoperation were calculated. Overall pooled hospital mortality for extended arch techniques was 8.6% (95% CI 7.2-10.0). Pooled data categorized by surgical technique resulted in hospital mortality of 11.9% for total arch, 8.6% total arch and frozen stented elephant trunk, 6.3% hemiarch and frozen stented elephant trunk and 5.5% total arch and 'warm stent graft'. Overall incidence of stroke for the entire cohort was 5.7% (95% CI 3.6-8.2). Rate of spinal cord ischaemia was 2.0% (95% CI 1.2-3.0). Pooled linearized rate of late mortality was 1.66%/pt-yr (95% CI 1.34-2.07) with linearized rate of re-operation of 1.62%/pt-yr (95% CI 1.24-2.05). Perioperative results of extended arch procedures are encouraging. Further follow-up is required to see if long-term complications are reduced with these emerging techniques. The proposed classification system will facilitate future comparison of short- and long-term results of different techniques of extended arch repair for ATAAD. © The Author 2016. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

Silicone Y-Stent Placement on the Secondary Left Carina.

PubMed

Oki, Masahide; Saka, Hideo

2015-01-01

The silicone Y-stent has mainly been used for the treatment of lesions around the main carina, and only a few case reports have been published on the technique for the lesions around the secondary left carina (LC2). We investigated the feasibility, efficacy and safety of a stenting technique using a silicone Y-stent for patients with airway stenosis around LC2. Patients who underwent airway stent placement between December 2010 and September 2014 in a single center were retrospectively reviewed. Under general anesthesia, using rigid and flexible bronchoscopes, the airway lumen was re-established followed by Y-stent placement on LC2. We performed 274 airway stenting procedures for 253 patients during the study period. Twelve of them (7 with lung cancer, 3 with esophageal cancer/carcinosarcoma, 1 with thyroid cancer and 1 with renal cancer) underwent a Y-stent placement on LC2. Respiratory symptoms were relieved in all patients. Six of 7 patients with supplemental oxygen, including the mechanically ventilated patient before stent placement, could be discharged without supplemental oxygen. The chest radiograph after the procedure showed increased lung volume in all 7 patients with partial or complete atelectasis. Median survival after stenting was 197 days at the time of data collection. Retention of secretions occurred in 1 and hemoptysis in another patient. Silicone Y-stent placement on LC2 is technically feasible, effective and acceptably safe. © 2015 S. Karger AG, Basel.

Comparative Computed Flow Dynamic Analysis of Different Optimization Techniques in Left Main Either Provisional or Culotte Stenting.

PubMed

Rigatelli, Gianluca; Dell'Avvocata, Fabio; Zuin, Marco; Giatti, Sara; Duong, Khanh; Pham, Trung; Tuan, Nguyen Si; Vassiliev, Dobrin; Daggubati, Ramesh; Nguyen, Thach

2017-12-01

Provisional and culotte are the most commonly used techniques in left main (LM) stenting. The impact of different post-dilation techniques on fluid dynamic of LM bifurcation has not been yet investigated. The aim of this study is to evaluate, by means of computational fluid dynamic analysis (CFD), the impact of different post-dilation techniques including proximal optimization technique (POT), kissing balloon (KB), POT-Side-POT and POT-KB-POT, 2-steps Kissing (2SK) and Snuggle Kissing balloon (SKB) on flow dynamic profile after LM provisional or culotte stenting. We considered an LM-LCA-LCX bifurcation reconstructed after reviewing 100 consecutive patients (mean age 71.4 ± 9.3 years, 49 males) with LM distal disease. The diameters of LAD and LCX were modelled according to the Finnet's law as following: LM 4.5 mm, LAD 3.5 mm, LCX 2.75 mm, with bifurcation angle set up at 55°. Xience third-generation stent (Abbot Inc., USA) was reconstructed and virtually implanted in provisional/cross-over and culotte fashion. POT, KB, POT-side-POT, POT-KB-POT, 2SK and SKB were virtually applied and analyzed in terms of the wall shear stress (WSS). Analyzing the provisional stenting, the 2SK and KB techniques had a statistically significant lower impact on the WSS at the carina, while POT seemed to obtain a neutral effect. In the wall opposite to the carina, the more physiological profile has been obtained by KB and POT with higher WSS value and smaller surface area of the lower WSS. In culotte stenting, at the carina, POT-KB-POT and 2SK had a very physiological profile; while at the wall opposite to the carina, 2SK and POT-KB-POT decreased significantly the surface area of the lower WSS compared to the other techniques. From the fluid dynamic point of view in LM provisional stenting, POT, 2SK and KB showed a similar beneficial impact on the bifurcation rheology, while in LM culotte stenting, POT-KB-POT and 2SK performed slightly better than the other techniques, probably reflecting a better strut apposition.

A manual carotid compression technique to overcome difficult filter protection device retrieval during carotid artery stenting.

PubMed

Nii, Kouhei; Nakai, Kanji; Tsutsumi, Masanori; Aikawa, Hiroshi; Iko, Minoru; Sakamoto, Kimiya; Mitsutake, Takafumi; Eto, Ayumu; Hanada, Hayatsura; Kazekawa, Kiyoshi

2015-01-01

We investigated the incidence of embolic protection device retrieval difficulties at carotid artery stenting (CAS) with a closed-cell stent and demonstrated the usefulness of a manual carotid compression assist technique. Between July 2010 and October 2013, we performed 156 CAS procedures using self-expandable closed-cell stents. All procedures were performed with the aid of a filter design embolic protection device. We used FilterWire EZ in 118 procedures and SpiderFX in 38 procedures. The embolic protection device was usually retrieved by the accessory retrieval sheath after CAS. We applied a manual carotid compression technique when it was difficult to navigate the retrieval sheath through the deployed stent. We compared clinical outcomes in patients where simple retrieval was possible with patients where the manual carotid compression assisted technique was used for retrieval. Among the 156 CAS procedures, we encountered 12 (7.7%) where embolic protection device retrieval was hampered at the proximal stent terminus. Our manual carotid compression technique overcame this difficulty without eliciting neurologic events, artery dissection, or stent deformity. In patients undergoing closed-cell stent placement, embolic protection device retrieval difficulties may be encountered at the proximal stent terminus. Manual carotid compression assisted retrieval is an easy, readily available solution to overcome these difficulties. Copyright © 2015 National Stroke Association. Published by Elsevier Inc. All rights reserved.

Comparative Analysis of Sequential Proximal Optimizing Technique Versus Kissing Balloon Inflation Technique in Provisional Bifurcation Stenting: Fractal Coronary Bifurcation Bench Test.

PubMed

Finet, Gérard; Derimay, François; Motreff, Pascal; Guerin, Patrice; Pilet, Paul; Ohayon, Jacques; Darremont, Olivier; Rioufol, Gilles

2015-08-24

This study used a fractal bifurcation bench model to compare 6 optimization sequences for coronary bifurcation provisional stenting, including 1 novel sequence without kissing balloon inflation (KBI), comprising initial proximal optimizing technique (POT) + side-branch inflation (SBI) + final POT, called "re-POT." In provisional bifurcation stenting, KBI fails to improve the rate of major adverse cardiac events. Proximal geometric deformation increases the rate of in-stent restenosis and target lesion revascularization. A bifurcation bench model was used to compare KBI alone, KBI after POT, KBI with asymmetric inflation pressure after POT, and 2 sequences without KBI: initial POT plus SBI, and initial POT plus SBI with final POT (called "re-POT"). For each protocol, 5 stents were tested using 2 different drug-eluting stent designs: that is, a total of 60 tests. Compared with the classic KBI-only sequence and those associating POT with modified KBI, the re-POT sequence gave significantly (p < 0.05) better geometric results: it reduced SB ostium stent-strut obstruction from 23.2 ± 6.0% to 5.6 ± 8.3%, provided perfect proximal stent apposition with almost perfect circularity (ellipticity index reduced from 1.23 ± 0.02 to 1.04 ± 0.01), reduced proximal area overstretch from 24.2 ± 7.6% to 8.0 ± 0.4%, and reduced global strut malapposition from 40 ± 6.2% to 2.6 ± 1.4%. In comparison with 5 other techniques, the re-POT sequence significantly optimized the final result of provisional coronary bifurcation stenting, maintaining circular geometry while significantly reducing SB ostium strut obstruction and global strut malapposition. These experimental findings confirm that provisional stenting may be optimized more effectively without KBI using re-POT. Copyright © 2015 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Endoscopic bilateral stent-in-stent placement for malignant hilar obstruction using a large cell type stent.

PubMed

Park, Jin Myung; Lee, Sang Hyub; Chung, Kwang Hyun; Jang, Dong Kee; Ryu, Ji Kon; Kim, Yong-Tae; Lee, Jae Min; Paik, Woo Hyun

2016-12-01

Bilateral stent-in-stent (SIS) self-expandable metal stent placement is technically challenging for palliation of unresectable malignant hilar obstruction. In the SIS technique, the uniform large cell type biliary stent facilitates contralateral stent deployment through the mesh of the first metallic stent. This study aimed to assess the technical success and clinical effectiveness of this technique with a uniform large cell type biliary stent. Thirty-one patients who underwent bilateral SIS placement using a large cell type stent were reviewed retrospectively. All patients showed malignant hilar obstruction (Bismuth types II, III, IV) with different etiologies. Sixteen (51.6%) patients were male. The mean age of the patients was 67.0+/-14.0 years. Most patients were diagnosed as having hilar cholangiocarcinoma (58.1%) and gallbladder cancer (29.0%). Technical success rate was 83.9%. Success was achieved more frequently in patients without masses obstructing the biliary confluence (MOC) than those with MOC (95.2% vs 60.0%, P=0.03). Functional success rate was 77.4%. Complications occurred in 29.0% of the patients. These tended to occur more frequently in patients with MOC (50.0% vs 19.0%, P=0.11). Median time to recurrent biliary obstruction was 188 days and median survival was 175 days. The large cell type stent can be used efficiently for bilateral SIS placement in malignant hilar obstruction. However, the risk of technical failure increases in patients with MOC, and caution is needed to prevent complications for these patients.

Fabrication of balloon-expandable self-lock drug-eluting polycaprolactone stents using micro-injection molding and spray coating techniques.

PubMed

Liu, Shih-Jung; Chiang, Fu-Jun; Hsiao, Chao-Ying; Kau, Yi-Chuan; Liu, Kuo-Sheng

2010-10-01

The purpose of this report was to develop novel balloon-expandable self-lock drug-eluting poly(ε-caprolactone) stents. To fabricate the biodegradable stents, polycaprolactone (PCL) components were first fabricated by a lab-scale micro-injection molded machine. They were then assembled and hot-spot welded into mesh-like stents of 3 and 5 mm in diameters. A special geometry of the components was designed to self-lock the assembled stents and to resist the external pressure of the blood vessels after being expanded by balloons. Characterization of the biodegradable PCL stents was carried out. PCL stents exhibited comparable mechanical property to that of metallic stents. No significant collapse pressure reduction and weight loss of the stents were observed after being submerged in PBS for 12 weeks. In addition, the developed stent was coated with paclitaxel by a spray coating technique and the release characteristic of the drug was determined by an in vitro elution method. The high-performance liquid chromatography analysis showed that the biodegradable stents could release a high concentration of paclitaxel for more than 60 days. By adopting the novel techniques, we will be able to fabricate biodegradable drug-eluting PCL stents of different sizes for various cardiovascular applications.

An effective technique to facilitate radiographic stone visualization with an internal stent during shock wave lithotripsy.

PubMed

Sundaram, C P; Saltzman, B

1998-10-01

We describe a simple method to assist stone localization during shock wave lithotripsy in the presence of a Double J stent. A 4F whistle tip ureteral catheter is passed alongside a previously inserted 6F Double J stent. The tip of the ureteral stent is positioned in the lower or mid third of the ureter. Contrast material is injected through the ureteral catheter during lithotripsy to assist stone localization. This technique has been successful in localization of poorly opacified renal stones during lithotripsy. Radiolucent and poorly calcified renal stones can be easily localized during shock wave lithotripsy, despite the presence of a Double J stent. No special catheters or stents are required for this technique.

Thoracic Endovascular Aortic Repair Combined with Assistant Techniques and Devices for the Treatment of Acute Complicated Stanford Type B Aortic Dissections Involving Aortic Arch.

PubMed

Zhang, Tianhua; Jiang, Weiliang; Lu, Haitao; Liu, Jianfeng

2016-04-01

The present study retrospectively reviewed and evaluated the effectiveness of thoracic endovascular aortic repair (TEVAR) combined with assistant techniques and devices for the treatment of acute complicated Stanford type B aortic dissections involving aortic arch. Fifty-six patients with acute complicated Stanford type B aortic dissection involving aortic arch were treated with TEVAR combined with hybrid procedure, chimney-graft technique, and branched stent grafts from January 2009 to March 2014. Seventeen patients undergone TEVAR combined with hybrid technique. Technical success was achieved in 94.1% with 5.8% of early mortality. Strokes occurred in a patient developing paraplegia, who completely recovered after lumbar drainage. Cardiocirculatory and pulmonary complications, bypass dysfunction or severe endoleak was not observed. Thirty patients undergone TEVAR combined with chimney technique with 100% technical success rate. Chimney-stent compression was observed in 1 patient, and another bare stent was deployed inside the first one. Three patients (10%) died during the study period. Immediate postoperative type I endoleak was detected in 4 cases (13.3%). TEVAR assisted by Castor branched aortic stent grafts in 9 patients was successful. Mortality during perioperative period and 30 days after TEVAR was null. No serious complications such as strokes, acute myocardial infarction, and ischemia of arms occurred. The results indicate that TEVAR combined with hybrid technique, chimney technique, and branched stent grafts is proven to be a technically feasible and effective treatment for acute complicated Stanford type B aortic dissection involving aortic arch in small cohort. Copyright © 2016 Elsevier Inc. All rights reserved.

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.

Causes of failure with Szabo technique - an analysis of nine cases.

PubMed

Jain, Rajendra Kumar; Padmanabhan, T N C; Chitnis, Nishad

2013-01-01

The objective of this case series is to identify and define causes of failure of Szabo technique in rapid-exchange monorail system for ostial lesions. From March 2009 to March 2011, 42 patients with an ostial lesion were treated percutaneously at our institution using Szabo technique in a monorail stent system. All patients received unfractionated heparin during intervention. Loading dose of clopidogrel, followed by clopidogrel and aspirin was administered. In 57% of patients, drug-eluting stents were used and in 42.8% patients bare metal stents. The stent was advanced over both wires, the target wire and the anchor wire. The anchor wire, which was passed through the proximal trailing strut of the stent helps to achieve precise stenting. The procedure was considered to be successful if stent was placed precisely covering the lesion and without stent loss or anchor wire prolapsing. Of the total 42 patients, the procedure was successful in 33, while failed in 9. Majority of failures were due to wire entanglement, which was fixed successfully in 3 cases by removing and reinserting the anchor wire. Out of other three failures, in one stent dislodgment occurred, stent could not cross the lesion in one and in another anchor wire got looped and prolapsed into target vessel. This case series shows that the Szabo technique, in spite of some difficulties like wire entanglement, stent dislodgement and resistance during stent advancement, is a simple and feasible method for treating variety of ostial lesions precisely compared to conventional angioplasty. Copyright © 2013 Cardiological Society of India. Published by Elsevier B.V. All rights reserved.

Causes of failure with Szabo technique – An analysis of nine cases

PubMed Central

Jain, Rajendra Kumar; Padmanabhan, T.N.C.; Chitnis, Nishad

2013-01-01

Objective The objective of this case series is to identify and define causes of failure of Szabo technique in rapid-exchange monorail system for ostial lesions. Methods and results From March 2009 to March 2011, 42 patients with an ostial lesion were treated percutaneously at our institution using Szabo technique in a monorail stent system. All patients received unfractionated heparin during intervention. Loading dose of clopidogrel, followed by clopidogrel and aspirin was administered. In 57% of patients, drug-eluting stents were used and in 42.8% patients bare metal stents. The stent was advanced over both wires, the target wire and the anchor wire. The anchor wire, which was passed through the proximal trailing strut of the stent helps to achieve precise stenting. The procedure was considered to be successful if stent was placed precisely covering the lesion and without stent loss or anchor wire prolapsing. Of the total 42 patients, the procedure was successful in 33, while failed in 9. Majority of failures were due to wire entanglement, which was fixed successfully in 3 cases by removing and reinserting the anchor wire. Out of other three failures, in one stent dislodgment occurred, stent could not cross the lesion in one and in another anchor wire got looped and prolapsed into target vessel. Conclusion This case series shows that the Szabo technique, in spite of some difficulties like wire entanglement, stent dislodgement and resistance during stent advancement, is a simple and feasible method for treating variety of ostial lesions precisely compared to conventional angioplasty. PMID:23809379

Endovascular aortic aneurysm repair with chimney and snorkel grafts: indications, techniques and results.

PubMed

Patel, Rakesh P; Katsargyris, Athanasios; Verhoeven, Eric L G; Adam, Donald J; Hardman, John A

2013-12-01

The chimney technique in endovascular aortic aneurysm repair (Ch-EVAR) involves placement of a stent or stent-graft parallel to the main aortic stent-graft to extend the proximal or distal sealing zone while maintaining side branch patency. Ch-EVAR can facilitate endovascular repair of juxtarenal and aortic arch pathology using available standard aortic stent-grafts, therefore, eliminating the manufacturing delays required for customised fenestrated and branched stent-grafts. Several case series have demonstrated the feasibility of Ch-EVAR both in acute and elective cases with good early results. This review discusses indications, technique, and the current available clinical data on Ch-EVAR.

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.

Computed tomography coronary stent imaging with iterative reconstruction: a trade-off study between medium kernel and sharp kernel.

PubMed

Zhou, Qijing; Jiang, Biao; Dong, Fei; Huang, Peiyu; Liu, Hongtao; Zhang, Minming

2014-01-01

To evaluate the improvement of iterative reconstruction in image space (IRIS) technique in computed tomographic (CT) coronary stent imaging with sharp kernel, and to make a trade-off analysis. Fifty-six patients with 105 stents were examined by 128-slice dual-source CT coronary angiography (CTCA). Images were reconstructed using standard filtered back projection (FBP) and IRIS with both medium kernel and sharp kernel applied. Image noise and the stent diameter were investigated. Image noise was measured both in background vessel and in-stent lumen as objective image evaluation. Image noise score and stent score were performed as subjective image evaluation. The CTCA images reconstructed with IRIS were associated with significant noise reduction compared to that of CTCA images reconstructed using FBP technique in both of background vessel and in-stent lumen (the background noise decreased by approximately 25.4% ± 8.2% in medium kernel (P

Deployment technique that takes advantage of the characteristics of Enterprise VRD2: an in vitro study.

PubMed

Chihara, Hideo; Ishii, Akira; Kikuchi, Takayuki; Ikeda, Hiroyuki; Arai, Daisuke; Miyamoto, Susumu

2017-10-01

Enterprise VRD, a stent frequently used to assist coil embolization of cerebral aneurysms, has been upgraded to reduce the risk of incomplete stent apposition (ISA), a known risk factor for thromboembolic complications. To compare the performances of Enterprise VRD and Enterprise VRD2 in curved vessels, and to investigate a deployment method that takes advantage of the features of Enterprise VRD2 to achieve better vessel wall apposition. A silicone vascular model connected to a temperature-adjustable perfusion circuit was used. First, Enterprise VRD and Enterprise VRD2 were deployed under fluoroscopy and then ISA was evaluated as the stent cross-sectional area ratio at the curved segment of the vessel. For the measurements, each stent was deployed in vessels with different angles of curvature. Second, the incidence of ISA after insertion of Enterprise VRD2 by the 'pushing over outer curve technique', in which stents are deployed along the outer curve of vessels with continuous wire advancement, was compared with 'Heller's push and pull technique'. For all stents, the cross-sectional area ratio decreased with acute curvature of the vessel. Comparisons of the two stents showed that Enterprise VRD2 was better than Enterprise VRD in maintaining a greater cross-sectional area ratio in curved vessels. In addition, kinking with an acute curvature was also minimized with Enterprise VRD2. Furthermore, ISA was reduced using our technique with Enterprise VRD2. Enterprise VRD2 is superior to Enterprise VRD in reducing ISA in curved vessels and can alter ISA according to the deployment technique used. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Double Y-stenting for tracheobronchial stenosis.

PubMed

Oki, Masahide; Saka, Hideo

2012-12-01

The purpose of the present study was to evaluate the feasibility, efficacy and safety of the double Y-stenting technique, by which silicone Y-stents are placed on both the main carina and another peripheral carina, for patients with tracheobronchial stenosis. Under general anaesthesia, using rigid and flexible bronchoscopes, a Dumon™ Y-stent (Novatech, La Ciotat, France) was first placed on the primary right or secondary left carina followed by another Y-stent on the main carina so as to insert the bronchial limb of the stent into the first Y-stent. Patients who underwent double Y-stent placement during 3 yrs and 1 month in a single centre were retrospectively reviewed. In the study period, 93 patients underwent silicone stent placement and 12 (13%) underwent double Y-stent placement (11 for right and one for left bronchus). A combination of Y-stents, 14 × 10 × 10 mm and 16 × 13 × 13 mm in outer diameter, were most frequently used. Dyspnoea was relieved in all patients. Six out of seven patients with supplemental oxygen before stent placement could be discharged without supplemental oxygen. Median survival after stenting was 94.5 days. One pneumothorax and one granuloma formation occurred. Double Y-stent placement for patients with tracheobronchial stenosis was technically feasible, effective and acceptably safe.

Novel application of an established technique for removing a knotted ureteric stent.

PubMed

Tempest, Heidi; Turney, Ben; Kumar, Sunil

2011-04-13

This report describes a case whereby a ureteric stent became knotted during removal and lodged within the upper ureter. The authors describe a novel minimally invasive technique to remove the knotted ureteric stent using the holmium laser.

Antegrade jj stenting after percutaneous renal procedures: The 'pull and push' technique.

PubMed

Ratkal, Jaideep M; Sharma, Elias

2015-06-01

A JJ stent is inserted antegradely after percutaneous renal procedures like percutaneous nephrolithotomy (PCNL) for renal calculus disease, and for endopyelotomy for pelvi-ureteric junction obstruction. We describe a technique for antegrade stent insertion after PCNL.

Role of endoscopic retrograde cholangiopancreatography in the management of benign biliary strictures: What’s new?

PubMed Central

Ferreira, Rosa; Loureiro, Rui; Nunes, Nuno; Santos, António Alberto; Maio, Rui; Cravo, Marília; Duarte, Maria Antónia

2016-01-01

Benign biliary strictures comprise a heterogeneous group of diseases. The most common strictures amenable to endoscopic treatment are post-cholecystectomy, post-liver transplantation, related to primary sclerosing cholangitis and to chronic pancreatitis. Endoscopic treatment of benign biliary strictures is widely used as first line therapy, since it is effective, safe, noninvasive and repeatable. Endoscopic techniques currently used are dilation, multiple plastic stents insertion and fully covered self-expandable metal stents. The main indication for dilation alone is primary sclerosing cholangitis related strictures. In the vast majority of the remaining cases, temporary placement of multiple plastic stents with/without dilation is considered the treatment of choice. Although this approach is effective, it requires multiple endoscopic sessions due to the short duration of stent patency. Fully covered self-expandable metal stents appear as a good alternative to plastic stents, since they have an increased radial diameter, longer stent patency, easier insertion technique and similar efficacy. Recent advances in endoscopic technique and various devices have allowed successful treatment in most cases. The development of novel endoscopic techniques and devices is still ongoing. PMID:26962404

Microvascular stent anastomosis using N-fibroin stents: feasibility, ischemia time, and complications.

PubMed

Smeets, Ralf; Vorwig, Oliver; Wöltje, Michael; Gaudin, Robert; Luebke, Andreas M; Beck-Broichsitter, Benedicta; Rheinnecker, Michael; Heiland, Max; Grupp, Katharina; Gröbe, Alexander; Hanken, Henning

2016-05-01

To evaluate a novel microvascular anastomosis technique using N-fibroin stents. Cylinder stents of 1 mm diameter and 5 mm length were fabricated using N-fibroin from silkworms. In 22 rats, aortas were dissected, and the stent was inserted into the two ends of the aorta and fixed using methylmethacrylate. Stent anastomosis was successful in 21 (96%) rats. The mean ischemia time was 7.4 minutes, significantly shorter than the 15.9 minutes in the control group with conventional sutures (P < .0001). After 4 months, anastomosis was functionally patent in all cases. However, elastic fibers remained interrupted in all stent anastomosis cases, and marked host rejection was evident at the stent anastomosis sites. Around the stents, thrombi were frequent (52%). Our study demonstrated the basic feasibility of stent anastomosis using N-fibroin stents and reduced ischemia time. However, thrombus formation, frequent and severe abdominal infections, and heavy host rejection remain critical issues. Copyright © 2016 Elsevier Inc. All rights reserved.

Carotid artery stenting: current and emerging options

PubMed Central

Morr, Simon; Lin, Ning; Siddiqui, Adnan H

2014-01-01

Carotid artery stenting technologies are rapidly evolving. Options for endovascular surgeons and interventionists who treat occlusive carotid disease continue to expand. We here present an update and overview of carotid stenting devices. Evidence supporting carotid stenting includes randomized controlled trials that compare endovascular stenting to open surgical endarterectomy. Carotid technologies addressed include the carotid stents themselves as well as adjunct neuroprotective devices. Aspects of stent technology include bare-metal versus covered stents, stent tapering, and free-cell area. Drug-eluting and cutting balloon indications are described. Embolization protection options and new direct carotid access strategies are reviewed. Adjunct technologies, such as intravascular ultrasound imaging and risk stratification algorithms, are discussed. Bare-metal and covered stents provide unique advantages and disadvantages. Stent tapering may allow for a more fitted contour to the caliber decrement between the common carotid and internal carotid arteries but also introduces new technical challenges. Studies regarding free-cell area are conflicting with respect to benefits and associated risk; clinical relevance of associated adverse effects associated with either type is unclear. Embolization protection strategies include distal filter protection and flow reversal. Though flow reversal was initially met with some skepticism, it has gained wider acceptance and may provide the advantage of not crossing the carotid lesion before protection is established. New direct carotid access techniques address difficult anatomy and incorporate sophisticated flow-reversal embolization protection techniques. Carotid stenting is a new and exciting field with rapidly advancing technologies. Embolization protection, low-risk deployment, and lesion assessment and stratification are active areas of research. Ample room remains for further innovations and developments. PMID:25349483

A “Train-Track” Technique in Anatomic Reconstruction of SVC Bifurcation Complicated by Cardiac Tamponade: An Introspection

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

Karuppasamy, Karunakaravel, E-mail: karuppk@ccf.org; Al-Natour, Mohammed, E-mail: mnatour85@msn.com; Gurajala, Ram Kishore, E-mail: gurajar@ccf.org

This report describes a stenting technique used to anatomically reconstruct superior vena cava (SVC) bifurcation in a patient with benign SVC syndrome. After recanalizing the SVC bifurcation, we exchanged two 0.035-in. wires for two 0.018-in. wires, deployed the SVC stent over these two wires (“train-track” technique), and stented each innominate vein over one wire. However, our decisions to recanalize both innominate veins, use the “buddy-wire” technique for SVC dilation, and dilate the SVC to 16 mm before stent deployment likely contributed to SVC tear, which was managed by resuscitation, SVC stent placement, and pericardial drainage. Here, we describe the steps ofmore » the train-track technique, which can be adopted to reconstruct other bifurcations; we also discuss the controversial aspects of this case.« less

Novel application of an established technique for removing a knotted ureteric stent

PubMed Central

Tempest, Heidi; Turney, Ben; Kumar, Sunil

2011-01-01

This report describes a case whereby a ureteric stent became knotted during removal and lodged within the upper ureter. The authors describe a novel minimally invasive technique to remove the knotted ureteric stent using the holmium laser. PMID:22701009

Antegrade jj stenting after percutaneous renal procedures: The ‘pull and push’ technique

PubMed Central

Ratkal, Jaideep M.; Sharma, Elias

2014-01-01

A JJ stent is inserted antegradely after percutaneous renal procedures like percutaneous nephrolithotomy (PCNL) for renal calculus disease, and for endopyelotomy for pelvi-ureteric junction obstruction. We describe a technique for antegrade stent insertion after PCNL. PMID:26413327

Modified jailed balloon technique for bifurcation lesions.

PubMed

Saito, Shigeru; Shishido, Koki; Moriyama, Noriaki; Ochiai, Tomoki; Mizuno, Shingo; Yamanaka, Futoshi; Sugitatsu, Kazuya; Tobita, Kazuki; Matsumi, Junya; Tanaka, Yutaka; Murakami, Masato

2017-12-04

We propose a new systematic approach in bifurcation lesions, modified jailed balloon technique (M-JBT), and report the first clinical experience. Side branch occlusion brings with a serious complication and occurs in more than 7.0% of cases during bifurcation stenting. A jailed balloon (JB) is introduced into the side branch (SB), while a stent is placed in the main branch (MB) as crossing SB. The size of the JB is half of the MB stent size. While the proximal end of JB attaching to MB stent, both stent and JB are simultaneously inflated with same pressure. JB is removed and then guidewires are recrossed. Kissing balloon dilatation (KBD) and/or T and protrusion (TAP) stenting are applied as needed. Between February 2015 and February 2016, 233 patients (254 bifurcation lesions including 54 left main trunk disease) underwent percutaneous coronary intervention (PCI) using this technique. Procedure success was achieved in all cases. KBD was performed for 183 lesions and TAP stenting was employed for 31 lesions. Occlusion of SV was not observed in any of the patients. Bench test confirmed less deformity of MB stent in M-JBT compared with conventional-JBT. This is the first report for clinical experiences by using modified jailed balloon technique. This novel M-JBT is safe and effective in the preservation of SB patency during bifurcation stenting. © 2017 Wiley Periodicals, Inc.

Difficult removal of fully covered self expandable metal stents (SEMS) for benign biliary strictures: the "SEMS in SEMS" technique.

PubMed

Tringali, Andrea; Blero, Daniel; Boškoski, Ivo; Familiari, Pietro; Perri, Vincenzo; Devière, Jacques; Costamagna, Guido

2014-06-01

Removal of biliary Fully Covered Self Expandable Metal Stents can fail due to stent migration and/or hyperplastic ingrowth/overgrowth. A case series of 5 patients with benign biliary strictures (2 post-cholecystectomy, 2 following liver transplantation and 1 related to chronic pancreatitis) is reported. The biliary stricture was treated by temporary insertion of Fully Covered Self Expandable Metal Stents. Stent removal failed due to proximal stent migration and/or overgrowth. Metal stent removal was attempted a few weeks after the insertion of another Fully Covered Metal Stent into the first one. The inner Fully Covered Self Expandable Metal Stent compressed the hyperplastic tissue, leading to the extraction of both the stents in all cases. Two complications were reported as a result of the attempt to stents removal (mild pancreatitis and self-limited haemobilia). In the present series, the "SEMS in SEMS" technique revealed to be effective when difficulties are encountered during Fully Covered Self Expandable Metal Stents removal. Copyright © 2014 Editrice Gastroenterologica Italiana S.r.l. Published by Elsevier Ltd. All rights reserved.

Urethroplasty after Urethral Urolume Stent: an International Multicenter Experience.

PubMed

Angulo, Javier C; Kulkarni, Sanjay; Pankaj, Joshi; Nikolavsky, Dmitriy; Suarez, Pedro; Belinky, Javier; Virasoro, Ramón; DeLong, Jessica; Martins, Francisco E; Lumen, Nicolaas; Giudice, Carlos; Suárez, Oscar A; Menéndez, Nicolás; Capiel, Leandro; López-Alvarado, Damian; Ramirez, Erick A; Venkatesan, Krishnan; Husainat, Maha M; Esquinas, Cristina; Arance, Ignacio; Gómez, Reynaldo; Santucci, Richard

2018-05-08

To evaluate the outcomes and factors affecting success of urethroplasty in patients with stricture recurrence after Urolume® urethral stent. Retrospective international multicenter study on patients treated with urethral reconstruction after Urolume® stent. Stricture and stent length, time between urethral stent insertion and urethroplasty, age, mode of stent retrieval, type of urethroplasty, complications and baseline and post-urethroplasty voiding parameters were analyzed. Successful outcome was defined as standard voiding, without need of any postoperative adjunctive procedure. Sixty-three patients were included. Stent was removed at urethroplasty in 61 patients. Reconstruction technique was excision and primary anastomosis in 14(22.2%), dorsal onlay buccal mucosa graft (BMG) 9(14.3%), ventral onlay BMG 6(9.5%), dorso-lateral onlay BMG 9(14.3%), ventral onlay plus dorsal inlay BMG 3(4.8%), augmented anastomosis 5(7.9%), pedicled flap urethroplasty 6(9.5%), 2-stage procedure 4(6.4%) and perineal urethrostomy 7(11.1%). Success rate was 81% at a mean 59.7+63.4months. Dilatation and/or internal urethrotomy was performed in 10(15.9%), redo-urethroplasty in 5(7.9%). Total IPSS, QoL, Qmax and PVR significantly improved (p<.0001). Complications occurred in 8(12.7%), all Clavien-Dindo <2. Disease-free survival rate after reconstruction was 88.1%,79.5% and 76.7% at 1,3 and 5-years respectively. Explant of individual strands followed by onlay BMG is the most common approach and was significantly advantageous over the other techniques (p=.018). Urethroplasty in patients with Urolume® urethral stents is a viable option of reconstruction with a high success rate and very acceptable complication rate. Numerous techniques are viable, however, urethral preservation, tine-by-tine stent extraction and use of BMG augmentation produced significantly better outcomes. Copyright © 2018 Elsevier Inc. All rights reserved.

A new technique of deploying dynamic y stent using flexible bronchoscope, video laryngoscope, and laryngeal mask airway.

PubMed

Obeidat, Shadi; Badin, Shadi; Khawaja, Imran

2010-04-01

Dynamic Y stents are used in tracheobronchial obstruction, tracheal stenosis, and tracheomalacia. Placement may be difficult and is usually accomplished using a rigid grasping forceps (under fluoroscopic guidance) or a rigid bronchoscope. We report using a new stent placement technique on an elderly patient with a central tracheobronchial tumor. It included using a flexible bronchoscope, video laryngoscope, and laryngeal mask airway. The new technique we used has the advantages of continuous direct endoscopic visualization during stent advancement and manipulation, and securing the airways with a laryngeal mask airway at the same time. This technique eliminates the need for intraoperative fluoroscopy.

Comparative Computed Flow Dynamic Analysis of Different Optimization Techniques in Left Main Either Provisional or Culotte Stenting

PubMed Central

Dell’Avvocata, Fabio; Zuin, Marco; Giatti, Sara; Duong, Khanh; Pham, Trung; Tuan, Nguyen Si; Vassiliev, Dobrin; Daggubati, Ramesh; Nguyen, Thach

2017-01-01

Abstract Background and Objectives Provisional and culotte are the most commonly used techniques in left main (LM) stenting. The impact of different post-dilation techniques on fluid dynamic of LM bifurcation has not been yet investigated. The aim of this study is to evaluate, by means of computational fluid dynamic analysis (CFD), the impact of different post-dilation techniques including proximal optimization technique (POT), kissing balloon (KB), POT-Side-POT and POT–KB-POT, 2-steps Kissing (2SK) and Snuggle Kissing balloon (SKB) on flow dynamic profile after LM provisional or culotte stenting. Methods We considered an LM-LCA-LCX bifurcation reconstructed after reviewing 100 consecutive patients (mean age 71.4 ± 9.3 years, 49 males) with LM distal disease. The diameters of LAD and LCX were modelled according to the Finnet’s law as following: LM 4.5 mm, LAD 3.5 mm, LCX 2.75 mm, with bifurcation angle set up at 55°. Xience third-generation stent (Abbot Inc., USA) was reconstructed and virtually implanted in provisional/cross-over and culotte fashion. POT, KB, POT-side-POT, POT-KB-POT, 2SK and SKB were virtually applied and analyzed in terms of the wall shear stress (WSS). Results Analyzing the provisional stenting, the 2SK and KB techniques had a statistically significant lower impact on the WSS at the carina, while POT seemed to obtain a neutral effect. In the wall opposite to the carina, the more physiological profile has been obtained by KB and POT with higher WSS value and smaller surface area of the lower WSS. In culotte stenting, at the carina, POT-KB-POT and 2SK had a very physiological profile; while at the wall opposite to the carina, 2SK and POT–KB-POT decreased significantly the surface area of the lower WSS compared to the other techniques. Conclusion From the fluid dynamic point of view in LM provisional stenting, POT, 2SK and KB showed a similar beneficial impact on the bifurcation rheology, while in LM culotte stenting, POT-KB-POT and 2SK performed slightly better than the other techniques, probably reflecting a better strut apposition. PMID:29340277

On-site customization of silicone stents: towards optimal palliation of complex airway conditions.

PubMed

Breen, David P; Dutau, Hervé

2009-01-01

Stents may be indicated as treatment of benign and malignant conditions of the central airways. Occasionally, aberrant and/or distorted airways secondary to therapy or surgery may preclude the use of commercially manufactured stents. The customization of stents is well described for nonpulmonary diseases, but to date there are only limited data in the literature on prosthesis customization for airway disease. To review all the different techniques and indications of on-site silicone stent customizations and their related complications. A retrospective study was undertaken to identify all patients who underwent treatment with a silicone stent which was customized on site by the physician. The study included subjects treated during an 8-year period. Forty-nine on-site customizations were performed in 43 patients (34 males, mean age 63 +/- 5.2 years). Stent customization was performed in 5.4% of the cases. Stent customization was performed for malignant and benign disease in 35 (81.3%) and 8 (18.7%) cases, respectively. In all cases, the stent deployed successfully and performed well while in situ. Stent manipulation did not increase complications. Customization of airway stents by the physician can lead to successful stenting of difficult airway lesions with a good short-term safety profile. Standard commercially available stents may have resulted in suboptimal management of complex airway pathologies. A prospective study is warranted to further investigate the safety profile and complications associated with stent customization. Copyright 2009 S. Karger AG, Basel.

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

Patel, Rakesh P., E-mail: rpatel9@nhs.net; Katsargyris, Athanasios, E-mail: kthanassos@yahoo.com; Verhoeven, Eric L. G., E-mail: Eric.Verhoeven@klinikum-nuernberg.de

The chimney technique in endovascular aortic aneurysm repair (Ch-EVAR) involves placement of a stent or stent-graft parallel to the main aortic stent-graft to extend the proximal or distal sealing zone while maintaining side branch patency. Ch-EVAR can facilitate endovascular repair of juxtarenal and aortic arch pathology using available standard aortic stent-grafts, therefore, eliminating the manufacturing delays required for customised fenestrated and branched stent-grafts. Several case series have demonstrated the feasibility of Ch-EVAR both in acute and elective cases with good early results. This review discusses indications, technique, and the current available clinical data on Ch-EVAR.

The effect of stent coating on stent deliverability: direct randomised comparison of drug eluting and bare metal stents using the same stent platform.

PubMed

Siminiak, Tomasz; Link, Rafał; Wołoszyn, Maciej; Kałmucki, Piotr; Baszko, Artur

2012-01-01

There is certain experimental and clinical evidence indicating that the covering of bare metal stents (BMS) with drug eluting polymers to produce drug eluting stents (DES) results in increased stent stiffness and modifies the mechanical properties of the stent platform. In addition, it has been speculated that the mechanical performance of DES, compared to BMS, may be related to the type of polymer used to cover stents. We aimed at evaluating the deliverability of DES with a lactate based biodegradable polymer and BMS in patients with stable coronary artery disease in a prospective randomised study. One hundred eleven consecutive patients (age: 36-77, mean 58.8 years) scheduled for routine angioplasty due to stable coronary disease were randomised to receive BMS (Chopin II(TM), Balton, Poland) or paclitaxel eluting stent (Chopin Luc(TM), Balton, Poland) using the same metal platform. Only patients scheduled for angioplasty using the direct implantation technique of a single stent were randomised. The exclusion criteria included patients 〉 80 years, multivessel disease and reference diameter of the target vessel 〉 3.5 mm. In the BMS group (n = 55; 35 males and 20 females), the mean diameter of implanted stents was 3.09 ± 0.40 and the mean length was 11.37 ± 2.80, whereas in the DES group (n = 56; 34 males and 22 females) the mean stent sizes were 3.02 ± 0.34 and 17.90 ± 7.38 mm, respectively (p 〉 0.05 for length). The groups did not significantly differ regarding the frequency of stent implantation to particular coronary vessels. The direct stenting technique was attempted and failed, leading to the stents' implantation after predilatation in five patients in the BMS group and six patients in the DES group. Failure of stent implantation and subsequent implantation of another stent type was observed in no BMS patients and in one DES patient (NS). Although stent covering with lactate based drug eluting polymer may increase its stiffness, it does not affect its deliverability in patients with stable coronary disease.

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.

In vitro comparison of intracranial stent visibility using various concentrations of gadolinium contrast agent under 1.5 T and 3 T MR angiography.

PubMed

Chiang, Chen-Hua; Tseng, Ying-Chi; Chen, Ai-Chi; Huang, Yen-Lin; Chen, David Yen-Ting; Chen, Chi-Jen; Lin, Yen-Kuang; Hsu, Hui-Ling

2017-04-01

MR angiography (MRA) is an increasingly used evaluation method following intracranial stenting. However, the various artifacts created by the stent limit this technique. The purpose of this study was to investigate the effects of various concentrations of gadolinium contrast agent on the visibility and signal characteristics of two stents using the a contrast enhanced MRA technique. Two intracranial stents (Enterprise and Helistent) were placed in polyvinyl chloride tubes as vascular phantoms. They were filled with six different doses of gadolinium contrast agent (1.0, 2.0, 4.0, 6.0, 8.0, and 10.0 mmol/L dimeglumine gadopentetate, respectively) and imaged using 3 T and 1.5 T MR systems. Relative in-stent signal (RIS) was calculated and artificial luminal narrowing (ALN) was obtained using pixel by pixel analysis. The Enterprise stent, performed in both 1.5 T and 3 T MR systems, showed mean RIS values much less than those for the Helistent for all different doses of gadolinium solution. Increased gadolinium concentration resulted in a gradual reduction in RIS values in the Enterprise group. Also, ALN in the Enterprise group showed no or little change with various gadolinium doses. The Enterprise stent demonstrated good luminal visibility regardless of gadolinium concentration. The relative in-stent signals were more predictable in the Enterprise stent with various doses of gadolinium. Therefore, the Enterprise stent has been shown to provide better in-stent visibility compared with the Helistent using various gadolinium doses. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Economic impact of angioplasty salvage techniques, with an emphasis on coronary stents: a method incorporating costs, revenues, clinical effectiveness and payer mix.

PubMed

Vaitkus, P T; Witmer, W T; Brandenburg, R G; Wells, S K; Zehnacker, J B

1997-10-01

We sought to broaden assessment of the economic impact of percutaneous transluminal coronary angioplasty (PTCA) revascularization salvage strategies by taking into account costs, revenues, the off-setting effects of prevented clinical complications and the effects of payer mix. Previous economic analyses of PTCA have focused on the direct costs of treatment but have not accounted either for associated revenues or for the ability of costly salvage techniques such as coronary stenting to reduce even costlier complications. Procedural costs, revenues and contribution margins (i.e., "profit") were measured for 765 consecutive PTCA cases to assess the economic impact of salvage techniques (prolonged heparin administration, thrombolysis, intracoronary stenting or use of perfusion balloon catheters) and clinical complications (myocardial infarction, coronary artery bypass graft surgery [CABG] or acute vessel closure with repeat PTCA). To assess the economic impact of various salvage techniques for failed PTCA, we used actual 1995 financial data as well as models of various mixes of fee-for-service, diagnosis-related group (DRG) and capitated payers. Under fee-for-service arrangements, most salvage techniques were profitable for the hospital. Stents were profitable at almost any level of clinical effectiveness. Under DRG-based systems, most salvage techniques such as stenting produced a financial loss to the hospital because one complication (CABG) remained profitable. Under capitated arrangements, stenting and other salvage modalities were profitable only if they were clinically effective in preventing complications in > 50% of cases in which they were used. The economic impact of PTCA salvage techniques depends on their clinical effectiveness, costs and revenues. In reimbursement systems dominated by DRG payers, salvage techniques are not rewarded, whereas complications are. Under capitated systems, the level of clinical effectiveness needed to achieve cost savings is probably not achievable in current practice. Further studies are needed to define equitable reimbursement schedules that will promote clinically effective practice.

New Technique for the Preservation of the Left Common Carotid Artery in Zone 2a Endovascular Repair of Thoracic Aortic Aneurysm

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

Juszkat, Robert, E-mail: radiologiamim@wp.pl; Kulesza, Jerzy; Zarzecka, Anna

2011-02-15

To describe a technique for the preservation of the left common carotid artery (CCA) in zone 2 endovascular repair of thoracic aortic aneurysm. This technique involves the placement of a guide wire into the left CCA via the right brachial artery before stent graft deployment to enable precise visualization and protection of the left CCA during the whole procedure. Of the 107 patients with thoracic endovascular aortic repair in our study, 32 (30%) had the left subclavian artery intentionally covered (landing zone 2). Eight (25%) of those 32 had landing zone 2a-the segment distally the origin of the left CCA,more » halfway between the origin of the left CCA and the left subclavian artery. In all patients, a guide wire was positioned into the left CCA via the right brachial artery before stent graft deployment. It is a retrospective study in design. In seven patients, stent grafts were positioned precisely. In the remaining patient, the positioning was imprecise; the origin of the left CCA was partially covered by the graft. A stent was implanted into the left CCA to restore the flow into the vessel. All procedures were performed successfully. The technique of placing a guide wire into the left CCA via the right brachial artery before stent graft deployment is a safe and effective method that enables the precise visualization of the left CCA during the whole procedure. Moreover, in case of inadvertent complete or partial coverage of the origin of the left CCA, it supplies safe and quick access to the artery for stent implantation.« less

Atherectomy in complex infrainguinal lesions: a review.

PubMed

Engelberger, S; van den Berg, J C

2015-02-01

In the femoropopliteal segment, endovascular revascularization techniques have gained the role as a first line treatment strategy. Nitinol stent placement has improved the short- and mid-term primary patency rates in most lesion types and is therefore widely applied. Stenting has several shortcomings as in-stent restenosis, stent fractures and foreign material being left behind in the vessel. The concept of atherectomy is plaque debulking. This results in a potential reduction of inflation pressure requirements in angioplasty. Stent placement and consecutive in-stent restenosis may be avoided. In this non systematic literature review, the performance of different atherectomy techniques, such as direct atherectomy, orbital atherectomy, laser debulking and rotational atherectomy in the treatment of complex femoropopliteal lesions, including long lesions, moderately to heavily calcified lesions as well as occlusions and in-stent restenosis, has been analyzed.

Jailed double-microcatheter technique following horizontal stenting for coil embolization of intracranial wide-necked bifurcation aneurysms: A technical report of two cases.

PubMed

Kitahara, Takahiro; Hatano, Taketo; Hayase, Makoto; Hattori, Etsuko; Miyakoshi, Akinori; Nakamura, Takehiko

2017-04-01

The horizontal stenting technique facilitates endovascular treatment of wide-necked bifurcation intracranial aneurysms. Previous literature shows, however, that subsequent coil embolization at initial treatment results in incomplete obliteration in many cases. The authors present two consecutive cases of wide-necked large bifurcation aneurysms to describe an additional coil embolization technique following horizontal stenting. The patients were a 53-year-old female with an unruptured internal carotid artery terminus aneurysm and a 57-year-old female with a recurrent basilar artery tip aneurysm. Both patients underwent endovascular treatment with horizontal stenting followed by coil embolization with jailed double-microcatheters. Immediate complete obliteration was achieved with no complications, and no recanalization was observed at the one-year follow-up in both cases. Coil embolization with jailed double-microcatheter technique following horizontal stenting is a safe and effective strategy for wide-necked bifurcation aneurysms.

External fixation of proximal tracheal airway stents: a modified technique.

PubMed

Majid, Adnan; Fernandez-Bussy, Sebastian; Kent, Michael; Folch, Erik; Fernandez, Liliana; Cheng, George; Gangadharan, Sidhu P

2012-06-01

Treatment of subglottic and proximal tracheal stenosis for nonsurgical candidates includes tracheostomy, Montgomery T tubes, and silicone stents. When used in lesions with concomitant malacia, silicone stents have a high incidence of migration. We describe a simple and effective technique of securing endoluminal stents using an Endo Close suturing device (Coviden, Boston, MA) and an external silicone button in 9 consecutive patients. Copyright © 2012 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Orbital atherectomy as an adjunct to debulk difficult calcified lesions prior to mesenteric artery stenting.

PubMed

Manunga, Jesse M; Oderich, Gustavo S

2012-08-01

To describe a technique in which percutaneous orbital atherectomy is used to debulk heavily calcified superior mesenteric artery (SMA) occlusions as an adjunct in patients undergoing angioplasty and stenting. The technique is demonstrated in a 62-year-old woman with a replaced right hepatic artery originating from an SMA occluded by densely calcified lesions. Via a left transbrachial approach, a 7-F MPA guide catheter was used to engage the ostium of the SMA, which was crossed using a catheter and guidewire. The calcified lesion was debulked using the 2-mm Diamondback 360° orbital atherectomy system. The wire was exchanged for a 0.014-inch filter wire and 0.018-inch guidewire. Using a 2-guidewire technique, the SMA was stented with a self-expanding stent for the distal lesion that crossed side branches and a balloon-expandable stent at the ostium. A 0.014-inch guidewire was placed into the replaced hepatic artery through a cell of the self-expanding stent, followed by deployment of a small balloon-expandable stent to address the residual lesion. The use of orbital atherectomy to debulk occluded and heavily calcified SMA lesions may optimize the technical results with angioplasty and stenting.

Subintimal Recanalization of Occluded Stents: The Substent Technique

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

Diamantopoulos, Athanasios, E-mail: adiamant@upatras.gr; Katsanos, Konstantinos; Spiliopoulos, Stavros

2013-08-01

PurposeApplication of metal stents is complicated by neointimal hyperplasia leading to vessel restenosis and reocclusion. Treatment options in cases presenting with complete occlusion of the stented segment and recurrent critical limb ischemia (CLI) are limited. We present the option of the subintimal/substent technique in dealing with occluded stents.MethodsThe study included patients presenting with recurrent CLI due to impaired blood flow as a result of complete occlusion of previously inserted metal stents and unsuccessful intraluminal crossing of the lesion via either the antegrade or retrograde approach. In these cases, crossing the occlusion through the subintimal/substent plane was attempted. Primary end pointsmore » included technical success, safety of the procedure, clinical improvement, and limb salvage, while secondary end points were patient survival, primary patency, and vessel restenosis rates at 1-year follow-up. Study end points were calculated by Kaplan-Meier survival analysis.ResultsBetween July 2006 and October 2011, a total of 14 patients (mean age 69.14 {+-} 12.59 years, 12 men) were treated with the substent technique and included in the analysis. Technical success rate was 85.71 % (12 of 14), with a total lesion length of 193.57 {+-} 90.78 mm. The mean occluded stented segment length was 90.21 {+-} 44.34 mm. In 10 (83.33 %) of 12 cases, a new stent had to be placed by the side of the old occluded one, while the remaining two cases (16.67 %) were treated only with balloon angioplasty. No serious adverse events were noted during the immediate postprocedural period. All successfully treated patients improved clinically. Estimated limb salvage was 90.9 %, and patient survival rate was 90.0 % at 1 year's follow-up. Primary patency was 45.50 % and vessel restenosis 77.30 %.ConclusionSubintimal recanalization of occluded metal stents through the substent plane is a valuable alternative treatment option, especially in patients with recurrent CLI with few alternatives.« less

[Anesthetic management of tracheobronchial stent insertion in patients who underwent laser resection, balloon dilatation and tracheostomy in advance].

PubMed

Hirai, Akiko; Hirose, Yoshifumi; Gamoh, Masahiro; Satoh, Minako

2005-10-01

We report successful management of tracheobronchial stent insertion under general anesthesia. In thirty-two cases, tracheobronchial stent insertion was performed under general anesthesia. The technique for airway management was chosen depending on the type of stent or the constriction level of the airway portion. We employed tracheostomy in order to avoid repeated intubations during the insertion of Dumon or Dynamic stent. In case of severe airway stenosis, laser resection or balloon dilatation was performed before stent insertion. We had 32 successful cases in 36 trials. Four trials failed due to insufficient expansion in one, mismatches of stent angle in one and pneumomediastinum in one. There was no exacerbation of respiratory condition in failed cases. There was no case who needed percutaneous cardiopulmonary support system. We managed tracheobronchial stent insertion under general anesthesia. Both the airway expansion by laser resection or balloon dilatation before stent insertion and also the insertion of Dumon or Dynamic stent through a tracheostomy were helpful strategies. These techniques facilitated more definitive airway maintenance and stable anesthetic management.

Correction of Stent Distortion and Overhanging Stent Struts during Left Main Bifurcation Stenting by Selective Distal Stent Cell Re-Wiring: A Novel Guidewire Approach

PubMed Central

Sabbah, Mahmoud; Kadota, Kazushige; Fuku, Yasushi; Mitsudo, Kazuaki

2015-01-01

Stent malapposition and overhanging stent struts in front of the side branch (SB) ostium are not uncommon following bifurcation stenting that might lead to stent thrombosis. We herein present 2 cases, in which optical frequency domain imaging and intravascular ultrasound effectively revealed stent malapposition and overhanging struts inside the ostium of the SB following left main coronary artery stenting. Therefore, we introduced a novel technique for rectification of these incidental findings by selective SB re-wiring through the most distal stent cell with the adjunctive help of a double lumen microcatheter. PMID:27122906

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.

A stent for co-delivering paclitaxel and nitric oxide from abluminal and luminal surfaces: Preparation, surface characterization, and in vitro drug release studies

NASA Astrophysics Data System (ADS)

Gallo, Annemarie; Mani, Gopinath

2013-08-01

Most drug-eluting stents currently available are coated with anti-proliferative drugs on both abluminal (toward blood vessel wall) and luminal (toward lumen) surfaces to prevent neointimal hyperplasia. While the abluminal delivery of anti-proliferative drugs is useful for controlling neointimal hyperplasia, the luminal delivery of such drugs impairs or prevents endothelialization which causes late stent thrombosis. This research is focused on developing a bidirectional dual drug-eluting stent to co-deliver an anti-proliferative agent (paclitaxel - PAT) and an endothelial cell promoting agent (nitric oxide - NO) from abluminal and luminal surfaces of the stent, respectively. Phosphonoacetic acid, a polymer-free drug delivery platform, was initially coated on the stents. Then, the PAT and NO donor drugs were co-coated on the abluminal and luminal stent surfaces, respectively. The co-coating of drugs was collectively confirmed by the surface characterization techniques such as Fourier transform infrared spectroscopy, scanning electron microscopy (SEM), 3D optical surface profilometry, and contact angle goniometry. SEM showed that the integrity of the co-coating of drugs was maintained without delamination or cracks formation occurring during the stent expansion experiments. In vitro drug release studies showed that the PAT was released from the abluminal stent surfaces in a biphasic manner, which is an initial burst followed by a slow and sustained release. The NO was burst released from the luminal stent surfaces. Thus, this study demonstrated the co-delivery of PAT and NO from abluminal and luminal stent surfaces, respectively. The stent developed in this study has potential applications in inhibiting neointimal hyperplasia as well as encouraging luminal endothelialization to prevent late stent thrombosis.

Fabrication and in vitro deployment of a laser-activated shape memory polymer vascular stent

PubMed Central

Baer, Géraldine M; Small, Ward; Wilson, Thomas S; Benett, William J; Matthews, Dennis L; Hartman, Jonathan; Maitland, Duncan J

2007-01-01

Background Vascular stents are small tubular scaffolds used in the treatment of arterial stenosis (narrowing of the vessel). Most vascular stents are metallic and are deployed either by balloon expansion or by self-expansion. A shape memory polymer (SMP) stent may enhance flexibility, compliance, and drug elution compared to its current metallic counterparts. The purpose of this study was to describe the fabrication of a laser-activated SMP stent and demonstrate photothermal expansion of the stent in an in vitro artery model. Methods A novel SMP stent was fabricated from thermoplastic polyurethane. A solid SMP tube formed by dip coating a stainless steel pin was laser-etched to create the mesh pattern of the finished stent. The stent was crimped over a fiber-optic cylindrical light diffuser coupled to an infrared diode laser. Photothermal actuation of the stent was performed in a water-filled mock artery. Results At a physiological flow rate, the stent did not fully expand at the maximum laser power (8.6 W) due to convective cooling. However, under zero flow, simulating the technique of endovascular flow occlusion, complete laser actuation was achieved in the mock artery at a laser power of ~8 W. Conclusion We have shown the design and fabrication of an SMP stent and a means of light delivery for photothermal actuation. Though further studies are required to optimize the device and assess thermal tissue damage, photothermal actuation of the SMP stent was demonstrated. PMID:18042294

An Update to Hepatobiliary Stents

PubMed Central

Moy, Brian T.; Birk, John W.

2015-01-01

Endoscopic stent placement is a common primary management therapy for benign and malignant biliary strictures. However, continuous use of stents is limited by occlusion and migration. Stent technology has evolved significantly over the past two decades to reduce these problems. The purpose of this article is to review current guidelines in managing malignant and benign biliary obstructions, current endoscopic techniques for stent placement, and emerging stent technology. What began as a simple plastic stent technology has evolved significantly to include uncovered, partially covered, and fully covered self-expanding metal stents (SEMS) as well as magnetic, bioabsorbable, drug-eluting, and antireflux stents.1 PMID:26357636

Endovascular revascularization for aortoiliac atherosclerotic disease

PubMed Central

Aggarwal, Vikas; Waldo, Stephen W; Armstrong, Ehrin J

2016-01-01

Atherosclerotic iliac artery disease is increasingly being treated with endovascular techniques. A number of new stent technologies can be utilized with high long-term patency, including self-expanding stents, balloon-expandable stents, and covered stents, but comparative data on these stent types and in more complex lesions are lacking. This article provides a review of currently available iliac stent technologies, as well as complex procedural aspects of iliac artery interventions, including approaches to the treatment of iliac bifurcation disease, long segment occlusions, choice of stent type, and treatment of iliac artery in-stent restenosis. PMID:27099509

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.

Successful Kissing Balloon Expandable Stent Graft Treatment for a Right Common Carotid Pseudoaneurysm Caused by Tracheotomy.

PubMed

Agyei, Justice O; Alvarez, Cynthia; Iqbal, Azher; Fanous, Andrew A; Siddiqui, Adnan H

2018-06-01

A rare complication following tracheotomy is common carotid artery (CCA) pseudoaneurysm. Treatment modalities for CCA pseudoaneurysm include surgical repair and single-artery balloon-covered stent graft technique. We describe successful treatment of tracheotomy-related CCA pseudoaneurysm with the "kissing balloon" expandable stent graft technique. We successfully implemented the kissing balloon expandable stent graft technique for treatment of a large, narrow-necked, bilobed CCA pseudoaneurysm that arose owing to a tracheotomy complication. The pseudoaneurysm was detected while performing a diagnostic angiogram of the aortic arch and surrounding vessels. The stent was deployed while the 2 balloons were introduced in a kissing manner such that they faced one another to avoid occlusion of either branch of the innominate artery coming into contact; 1 balloon was inflated at the origin of the right subclavian artery, and the other was inflated at the right innominate artery simultaneously. The pseudoaneurysm was successfully contained; normal blood flow was restored in the CCA. The balloons were deflated and withdrawn. The patient remained neurologically intact after the procedure. The kissing balloon technique is a safe and effective alternative to surgical repair, as it prevents morbidities associated with the surgical procedure. Also, this technique decreases the risk of major side-branch occlusion associated with the single-artery balloon-covered stent graft technique. Copyright © 2018 Elsevier Inc. All rights reserved.

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.

Early Results of the PETTICOAT Technique for the Management of Acute Type A Aortic Dissection.

PubMed

Kotha, Vamshi Krishna; Pozeg, Zlatko I; Herget, Eric J; Moon, Michael C; Appoo, Jehangir J

2017-08-01

Conventional surgical techniques for acute Type A aortic dissection (ATAAD) generally fail to address residual dissection in the descending aorta. The persistence of a false lumen is associated with visceral malperfusion in the acute setting and adverse aortic remodeling in the chronic setting. Hybrid aortic arch repair techniques may improve perioperative and long-term mortality by expanding the true lumen and obliterating the false lumen. However, there is a limit to the extent of aortic coverage due to the concomitant risk of spinal cord ischemia. In Type B dissection, the PETTICOAT (Provisional Extension To Induce Complete Attachment) technique, which entails stent graft coverage of the primary intimal tear followed by bare metal stent placement distally, may improve true lumen caliber and promote false lumen thrombosis without increasing the risk of spinal cord ischemia, as intercostal branches remain perfused through the bare metal stents. The technique of hybrid arch with surgical creation of a Dacron landing zone covering a stent graft in the proximal descending aorta and bare metal stents in the thoraco-abdominal aorta is a promising concept in the treatment of ATAAD.

Novel use of a percutaneous endoscopic gastrostomy tube fastener for securing silicone tracheal stents in patients with benign proximal airway obstruction.

PubMed

Musani, Ali I; Jensen, Kurt; Mitchell, John D; Weyant, Michael; Garces, Katherine; Hsia, David

2012-04-01

Benign tracheal obstruction occurs for a variety of reasons. Bronchoscopic intervention includes silicone stent placement, which effectively maintains airway patency. Stent migration is a common complication, particularly when placed in the proximal trachea. We used a novel technique of securing tracheal stents with a percutaneous endoscopic gastrostomy tube fastener (PEG-TF) to prevent stent migration. The purpose of this study was to determine the feasibility of securing silicone stents in the proximal trachea with PEG-TF. Silicone stents were placed under general anesthesia by rigid bronchoscopy in 7 consecutive patients with inoperable benign proximal tracheal obstruction. PEG-TFs were placed under sterile conditions with direct bronchoscopic visualization. A needle was inserted through the anterior neck and silicone stent wall allowing stylet introduction of a T-fastener into the interior of the stent. The T-fastener was secured externally by a metal clamp and cotton pledget at the surface of the neck. Patients had routine outpatient follow-up and covered the external portion of the PEG-TF with a waterproof dressing when showering. All 7 PEG-TFs were placed without complications. The PEG-TFs were left in for 1 to 25 weeks. Complications of the PEG-TF included localized cellulitis and suture breakage. No stent migration occurred while the fastener was in place. Two stents were removed within 2 weeks due to patient's difficulty tolerating the stent. Securing silicone stents in the proximal trachea is feasible and may prevent stent migration, but further study and possible modification of the PEG-TF device are needed.

Safety of endoscopic removal of self-expandable stents after treatment of benign esophageal diseases.

PubMed

van Halsema, Emo E; Wong Kee Song, Louis M; Baron, Todd H; Siersema, Peter D; Vleggaar, Frank P; Ginsberg, Gregory G; Shah, Pari M; Fleischer, David E; Ratuapli, Shiva K; Fockens, Paul; Dijkgraaf, Marcel G W; Rando, Giacomo; Repici, Alessandro; van Hooft, Jeanin E

2013-01-01

Temporary placement of self-expandable stents has been increasingly used for the management of benign esophageal diseases. To evaluate the safety of endoscopic removal of esophageal self-expandable stents placed for the treatment of benign esophageal diseases. Multicenter retrospective study. Six tertiary care centers in the United States and Europe. A total of 214 patients with benign esophageal diseases undergoing endoscopic stent removal. Endoscopic stent removal. Endoscopic techniques for stent removal, time to stent removal, and adverse events related to stent removal. A total of 214 patients underwent a total of 329 stent extractions. Stents were mainly placed for refractory strictures (49.2%) and fistulae (49.8%). Of the removed stents, 52% were fully covered self-expandable metal stents (FCSEMSs), 28.6% were partially covered self-expandable metal stents (PCSEMSs), and 19.5% were self-expandable plastic stents. A total of 35 (10.6%) procedure-related adverse events were reported, including 7 (2.1%) major adverse events. Multivariate analysis revealed that use of PCSEMSs (P < .001) was a risk factor for adverse events during stent removal. Favorable factors for successful stent removal were FCSEMSs (P ≤ .012) and stent migration (P = .010). No significant associations were found for stent indwelling time (P = .145) and stent embedding (P = .194). Retrospective analysis, only tertiary care centers. With an acceptable major adverse event rate of 2.1%, esophageal stent removal in the setting of benign disease was found to be a safe and feasible procedure. FCSEMSs were more successfully removed than self-expandable plastic stents and PCSEMSs. Adverse events caused by stent removal were not time dependent. Copyright © 2013 American Society for Gastrointestinal Endoscopy. Published by Mosby, Inc. All rights reserved.

New anastomosis technique for (laparoscopic) instrumental small-diameter anastomosis.

PubMed

Schöb, O; Schmid, R; Schlumpf, R; Klotz, H P; Spiess, M; Largiadèr, F

1995-04-01

This study presents a new technique for visceral anastomosis. The principle consists of connecting the two parts to be anastomosed around a reabsorbable stent which is transluminally introduced into small-diameter viscus, where it is fixed. Advancing a larger tube along the axis of the machine, the larger, perforated viscus is inverted and pulled over the stent, and finally a rubber band pops off the machine endoluminally in order to fix the intestinal walls in seroserosal contact onto the stent. To evaluate this "micro" anastomosis, a biliary bypass (choledochojejunostomy and roux-en-y-loop) was performed in ten pigs. Nine of ten animals showed biliary bypass with good runoff in contrast radiography and completely reabsorbed stent after a 3-month follow-up. Weight gain, bilirubin, and alkaline phosphatase were normal. This technology demonstrates a safe and quick way to perform instrumental "micro" anastomosis without remnant foreign material.

Adult Patent Ductus Arteriosus: Treatment with a Stent-Graft

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

Munoz, J.J., E-mail: jjmrc@telefonica.net; Urbaneja, A.; Gonzalez, N.

We present the case of a 63-year-old woman with a short patent ductus arteriosus and aneurysmal pulmonary arteries who was treated by placement of a stent-graft. The technique proved simple and safe. Further research is required to improve the design of stent-grafts and their release system for use of this technique in adult patients with this disorder.

TOKYO criteria 2014 for transpapillary biliary stenting.

PubMed

Isayama, Hiroyuki; Hamada, Tsuyoshi; Yasuda, Ichiro; Itoi, Takao; Ryozawa, Shomei; Nakai, Yousuke; Kogure, Hirofumi; Koike, Kazuhiko

2015-01-01

It is difficult to carry out meta-analyses or to compare the results of different studies of biliary stents because there is no uniform evaluation method. Therefore, a standardized reporting system is required. We propose a new standardized system for reporting on biliary stents, the 'TOKYO criteria 2014', based on a consensus among Japanese pancreatobiliary endoscopists. Instead of stent occlusion, we use recurrent biliary obstruction, which includes occlusion and migration. The time to recurrent biliary obstruction was estimated using Kaplan-Meier analysis with the log-rank test. We can evaluate both plastic and self-expandable metallic stents (uncovered and covered). We also propose specification of the cause of recurrent biliary obstruction, identification of complications other than recurrent biliary obstruction, indication of severity, measures of technical and clinical success, and a standard for clinical care. Most importantly, the TOKYO criteria 2014 allow comparison of biliary stent quality across studies. Because blocked stents can be drained not only using transpapillary techniques but also by an endoscopic ultrasonography-guided transmural procedure, we should devise an evaluation method that includes transmural stenting in the near future. © 2014 The Authors. Digestive Endoscopy © 2014 Japan Gastroenterological Endoscopy Society.

Argon plasma coagulation in the management of uncovered tracheal stent fracture

PubMed Central

Ching, Yiu-Hei; Geck, Robert D.; Andrews, Arthur D.; Rumbak, Mark J.; Camporesi, Enrico M.

2014-01-01

Endotracheal and endobronchial stenting, particularly with uncovered stents, can be complicated by stent fracture, granulation tissue formation, direct airway injury, and airway obstruction. While stent removal is possible, it can result in significant complications and long-term benefit is not guaranteed. Argon plasma coagulation can be employed to trim fractured stent fragments and remove granulation tissue simultaneously. In this manuscript, we report a case and describe our experience with using this technique. PMID:26029557

Restrictive bare stent prevents distal stent graft-induced new entry in endovascular repair of type B aortic dissection.

PubMed

Zhao, Yang; Yin, Henghui; Chen, Yitian; Wang, Mian; Zheng, Liang; Li, Zilun; Chang, Guangqi

2018-01-01

Distal stent graft-induced new entry (SINE) can occur after thoracic endovascular aortic repair (TEVAR) of type B aortic dissection. This study investigated the mechanism of distal SINE and its prevention using a restrictive bare stent (RBS) technique. From January 2013 to December 2014, 68 consecutive type B aortic dissection patients received endovascular repair at our center. The RBS technique was used with distal oversizing (between the diameter of the thoracic stent graft and the descending aorta true lumen diameter at the level of the intended distal edge of the thoracic stent graft) >20%. Twenty-three patients received TEVAR with a single thoracic stent graft (TEVAR group, n = 23); the rest received TEVAR combined with the RBS technique (TEVAR + RBS group, n = 45). Four distal SINEs occurred in the TEVAR group. Distal oversizing (69.7% ± 35.5% vs 31.2% ± 24.5%; P = .005) and expansion mismatch ratio (132.2% ± 16.9% vs 106.5% ± 11.6%; P < .05) were significantly higher in the SINE patients. Compared with standard TEVAR, TEVAR + RBS was associated with significantly lower distal oversizing (TEVAR vs TEVAR + RBS group, 59.8% ± 24.7% vs 16.7% ± 7.6%; P < .05), lower expansion mismatch ratio (113.8% ± 14.6% vs 103.8% ± 11.7%; P = .012), and lower distal SINE rate (4/23 [17.4%] vs 0/45 [0%]; P = .011). Compared with the TEVAR group, the false lumen was reduced significantly at the level of the RBS distal edge (P = .029). Excessive distal oversizing and distal expansion mismatch ratio may contribute to the occurrence of distal SINE. The RBS technique reduced the incidence of distal SINE. Based on our midterm and long-term observations, implantation of an RBS may improve aortic remodeling. Copyright © 2017 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

Influence of surface microroughness by plasma deposition and chemical erosion followed by TiO2 coating upon anticoagulation, hydrophilicity, and corrosion resistance of NiTi alloy stent.

PubMed

Wang, Gui-Xue; Shen, Yang; Zhang, He; Quan, Xue-Jun; Yu, Qing-Song

2008-06-15

Two different surface modification techniques were used to change the surface morphology and roughness of stents at the micrometer level, and eventually improve their surface adhesion properties with respect to endothelial cells. One was chemical erosion followed by sol-gel TiO(2) coating, and the other was low temperature gas plasma deposition. After surface modification, the biocompatibility including the anticoagulation properties, hydrophilicity, and corrosion resistance of these stents was evaluated. It was found that both techniques could change the surface morphology of the stents with microroughness. In comparison with the control, the treated NiTi alloy intravascular stents showed increased surface hydrophilicity and enhanced anticoagulation properties. However, the corrosion properties of the stents were not improved significantly.

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.

Expandable metal stents for endoscopic bilateral stent-within-stent placement for malignant hilar biliary obstruction.

PubMed

Chahal, Prabhleen; Baron, Todd H

2010-01-01

Placement of biliary stents is effective for palliation of unresectable hilar malignant biliary obstruction. However, when bilateral self-expandable metal stents (SEMSs) are used, placement can be technically challenging. In many studies, side-by-side placement is performed, although it is unclear whether this is the most anatomical and functional approach. We sought to assess the technical feasibility and effectiveness of deploying bilateral SEMSs with a stent-within-stent approach using commercially available stents with a large cell width. Retrospective study. Tertiary care medical center. Patients with malignant biliary hilar obstruction referred for endoscopic palliation of obstructive jaundice. Technical success, ie, successful bilateral SEMS placement across the stricture; functional success, ie, decrease in pretreatment bilirubin level; early and late complications; and stent patency. Bilateral biliary drainage was attempted and successfully established in 21 patients with malignant hilar obstruction (15 men, 6 women; mean age 63.7 [standard deviation 13.9] years), resulting in clinical improvement of obstructive symptoms. Median follow-up was 6.14 months (interquartile range 3.5-9.5 months). There were 1 (5%) early and 7 (33%) late stent occlusions that required endoscopic reintervention. The 30-day mortality rate was 10% (2 deaths). Retrospective study of a series of cases treated at a tertiary care center by expert endoscopists. This simple technique was performed by using an open-cell expandable metal stent is technically feasible and easy and allows bilateral placement of SEMSs in patients with unresectable hilar malignancy. 2010 American Society for Gastrointestinal Endoscopy. Published by Mosby, Inc. All rights reserved.

Fixation of silicone stents in the subglottic trachea: preventing stent migration using a fixation apparatus.

PubMed

Miwa, Keisuke; Takamori, Shinzo; Hayashi, Akihiro; Fukunaga, Mari; Shirouzu, Kazuo

2004-12-01

Silicone stents are widely used to treat benign or malignant airway stenosis. However, since straight silicone stents placed into the subglottic trachea to treat stenosis display a high risk of migration, novel approaches are required. The present report outlines our method of external fixation for silicone stents in the subglottic trachea. This technique utilizes a fixation apparatus, is readily performed, and may help to overcome the hesitation seen in placing silicone stents for subglottic tracheal stenosis.

Treatment of cerebral vasospasm with self-expandable retrievable stents: proof of concept.

PubMed

Bhogal, Pervinder; Loh, Yince; Brouwer, Patrick; Andersson, Tommy; Söderman, Michael

2017-01-01

To report our preliminary experience with the use of stent retrievers to cause vasodilation in patients with delayed cerebral vasospasm secondary to subarachnoid hemorrhage. Four patients from two different high volume neurointerventional centers developed cerebral vasospasm following subarachnoid hemorrhage. In addition to standard techniques for the treatment of cerebral vasospasm, we used commercially available stent retrievers (Solitaire and Capture stent retrievers) to treat the vasospastic segment including M2, M1, A2, and A1. We evaluated the safety of this technique, degree of vasodilation, and longevity of the effect. Stent retrievers can be used to safely achieve cerebral vasodilation in the setting of delayed cerebral vasospasm. The effect is long-lasting (>24 hours) and, in our initial experience, carries a low morbidity. We have not experienced any complications using this technique although we have noted that the radial force was not sufficient to cause vasodilation in some instances. The vasospasm did not return in the vessel segments treated with stent angioplasty in any of these cases. In two of our cases stent angioplasty resulted in the reversal of focal neurological symptoms. Stent retrievers can provide long-lasting cerebral vasodilation in patients with delayed cerebral vasospasm. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Endovascular Repair of Acute Symptomatic Pararenal Aortic Aneurysm With Three Chimney and One Periscope Graft for Complete Visceral Artery Revascularization

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

Brechtel, Klaus, E-mail: klaus.brechtel@med.uni-tuebingen.de; Ketelsen, Dominik; Endisch, Andrea

2012-04-15

PurposeTo describe a modified endovascular technique for complete revascularization of visceral and renal arteries in symptomatic pararenal aortic aneurysm (PRAA).TechniqueArterial access was surgically established in both common femoral arteries (CFAs) and the left subclavian artery (LSA). Revascularization of the left renal artery, the celiac trunk, and the superior mesenteric artery was performed through one single sheath via the LSA. Suitable covered stents were put in the aortic branches but not deployed. The right renal artery was accessed over the left CFA. Due to the longitudinal extension of the presented aneurysm two stent-grafts were introduced via the right CFA. After deployingmore » the aortic stent-grafts, all covered stents in the side branches were deployed consecutively with a minimum overlap of 5 mm over the cranial and caudal stent-graft edges. Simultaneous ballooning was performed to fully expand all stent-grafts and warranty patency. Conclusion: This is the first report in the literature of chimney grafting in PRAA for complete revascularization of visceral and renal branches by using more than two covered stents introduced from one side through one single sheath. However this technique is modified, it should be used only in bailout situations when branched stent-grafts are not available and/or surgery is not suitable.« less

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.

Nasojejunal-stent technique (NJST): A new system to prevent fully covered metal stent migration in the treatment of benign esophageal diseases.

PubMed

Hernández Mondragón, Oscar Víctor; Cuellar, Raquel Palos; Murcio Pérez, Enrique

2018-05-19

Fully covered self-expandable metal stents (FCSEMS) have been used for the treatment of benign esophageal conditions such as perforation, leaks, and strictures [1]; high clinical success is reported [2]. Different anchoring methods have been described (clips, suturing devices, over-the-scope clips and Shim technique [2]), because of high migration rates (4-36%) [3,4]. However, not all cases are candidates, mostly in "difficult" cases where enteral feeding is needed [5]. We report the use of the nasojejunal-stent technique (NJST) to prevent migration of FCSEMS in three difficult cases. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Strategies for the Management of SVC Stent Migration into the Right Atrium

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

Taylor, J. D., E-mail: drjeremytaylor@yahoo.co.uk; Lehmann, E. D.; Belli, A.-M.

Purpose. Stent migration into the right atrium is a potentially fatal complication of stenting in the venous system and is most likely to occur during the treatment of superior vena cava obstruction. Endovascular approaches that can salvage this hazardous situation are described and the keys to successful treatment are highlighted. Materials and Methods. Four different strategies are reviewed: (1) snaring the stent directly, (2) angioplasty balloon-assisted snaring of the stent, (3) guide wire-assisted snaring of the stent, and (4) superior vena cava-to-inferior vena cava bridging stent. Results. These techniques have been employed in the successful management of four cases. Nomore » short- or long-term complications as a result of these maneuvers have been identified. Additional treatment of the underlying disease was possible at the same time in each case. Conclusion. We conclude that prompt management of right atrial stent migration is essential and can be successfully achieved by a variety of 'bale-out' techniques which are within the technical range of most interventional radiologists.« less

BIODEGRADABLE BILIARY STENTS: A NEW APPROACH FOR THE MANAGEMENT OF HEPATICOJEJUNOSTOMY STRICTURES FOLLOWING BILE DUCT INJURY. PROSPECTIVE STUDY

PubMed Central

GIMÉNEZ, Mariano E.; PALERMO, Mariano; HOUGHTON, Eduardo; ACQUAFRESCA, Pablo; FINGER, Caetano; VERDE, Juan M.; CÚNEO, Jorge Cardoso

2016-01-01

ABSTRACT Background: Once a biliary injury has occurred, repair is done by a hepaticojejunostomy. The most common procedure is to perform a dilatation with balloon with a success of 70 %. Success rates range using biodegradable stents is from 85% to 95%. Biodegradable biliary stents should change the treatment of this complication. Aim: To investigate the use of biodegradable stents in a group of patients with hepaticojejunonostomy strictures. Methods: In a prospective study 16 biodegradable stents were placed in 13 patients with hepaticojejunostomy strictures secondary to bile duct repair of a biliary surgical injury. Average age was 38.7 years (23-67), nine were female and four male. All cases had a percutaneous drainage before at the time of biodegradable stent placement. Results: In one case, temporary haemobilia was present requiring blood transfusion. In another, pain after stent placement required intravenous medication. In the other 11 patients, hospital discharge was the next morning following stent placement. During the patient´s follow-up, none presented symptoms during the first nine months. One patient presented significant alkaline phosphatase elevation and stricture recurrence was confirmed. One case had recurrence of cholangitis 11 months after the stent placement. 84.6% continued asymptomatic with a mean follow-up of 20 months. Conclusion: The placement of biodegradable stents is a safe and feasible technique. Was not observed strictures caused by the stent or its degradation. It could substitute balloon dilation in strictures of hepaticojejunostomy. PMID:27438039

Ureteral Stents. New Materials and Designs

NASA Astrophysics Data System (ADS)

Monga, Manoj

2008-09-01

Issues of stent migration and challenges of stent placement can be addressed adequately with current stent designs and materials, and an emphasis on precision in technique. Future changes in ureteral stents will need to maintain the current standard that has been set with existing devices in these regards. In contrast, new advances are sorely needed in encrustation and infection associated with ureteral stents. The main target for future development in ureteral stent materials lies in a biodegradable stent that degrades either on demand or degrades reliably within one-month with predictable degradation patterns that do not predispose to urinary obstruction, discomfort or need for secondary procedures. The main target for future development in ureteral stent design is improved patient comfort.

Plastic Biliary Stent Migration During Multiple Stents Placement and Successful Endoscopic Removal Using Intra-Stent Balloon Inflation Technique: A Case Report and Literature Review.

PubMed

Calcara, Calcedonio; Broglia, Laura; Comi, Giovanni; Balzarini, Marco

2016-02-05

Late migration of a plastic biliary stent after endoscopic placement is a well known complication, but there is little information regarding migration of a plastic stent during multiple stents placement. A white man was hospitalized for severe jaundice due to neoplastic hilar stenosis. Surgical eligibility appeared unclear on admission and endoscopy was carried out, but the first stent migrated proximally at the time of second stent insertion. After failed attempts with various devices, the migrated stent was removed successfully through cannulation with a dilation balloon. The migration of a plastic biliary stent during multiple stents placement is a possible complication. In this context, extraction can be very complicated. In our patient, cannulation of a stent with a dilation balloon was the only effective method.

Biocompatibility study of plasma-coated nitinol (NiTi alloy) stents.

PubMed

Wang, G; Shen, Y; Cao, Y; Yu, Q; Guidoin, R

2007-12-01

The authors aimed to assess the surface modification effects of plasma coatings on biocompatibility of nitinol intravascular stent in terms of anticoagulation, haemocytolysis rate, hydrophilicity, cytotoxicity and so on. In order to improve their surface adhesive properties to endothelial cells, NiTi alloy intravascular stents were treated and coated using a low-temperature plasma deposition technique. It was found that plasma coating changed the surface morphology of the stents to a micron-level surface roughness in the range of 1-5 microm. In comparison with the untreated control, the plasma-treated NiTi alloy intravascular stents showed increased surface hydrophilicity and enhanced anticoagulation property. Testing results on plasma-coated NiTi stents indicated that they complied with the standard of national biologic safety evaluation of medical apparatus and instrument (GB/T16886-1997, People's Republic of China) in terms of haemocytolysis rate, cytotoxicity and pyretogen.

Endovascular Exclusion of Visceral Artery Aneurysms with Stent-Grafts: Technique and Long-Term Follow-up

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

Rossi, Michele; Rebonato, Alberto, E-mail: albertorebonato@libero.it; Greco, Laura

This paper describes four cases of visceral artery aneurysms (VAAs) successfully treated with endovascular stent-grafts and discusses the endovascular approach to VAAs and the long-term results. Four balloon expandable stent-grafts were used to treat three splenic artery aneurysms and one bleeding common hepatic artery pseudoaneurysm. The percutaneous access site and the materials were chosen on the basis of CT angiography findings. In all cases the aneurysms were successfully excluded. In one case a splenic infarction occurred, with nonrelevant clinical findings. At 16- to 24-month follow-up three patients had patent stents and complete exclusion and shrinkage of the aneurysms. One patientmore » died due to pancreatitis and sepsis, 16 days after successful stenting and exclusion of a bleeding pseudoaneurysm. We conclude that endovascular treatment using covered stent-grafts is a valid therapeutic option for VAAs. Multislice CT preoperative study helps in planning stent-graft positioning.« less

Early Results of the PETTICOAT Technique for the Management of Acute Type A Aortic Dissection

PubMed Central

Kotha, Vamshi Krishna; Pozeg, Zlatko I.; Herget, Eric J.; Moon, Michael C.; Appoo, Jehangir J.

2017-01-01

Conventional surgical techniques for acute Type A aortic dissection (ATAAD) generally fail to address residual dissection in the descending aorta. The persistence of a false lumen is associated with visceral malperfusion in the acute setting and adverse aortic remodeling in the chronic setting. Hybrid aortic arch repair techniques may improve perioperative and long-term mortality by expanding the true lumen and obliterating the false lumen. However, there is a limit to the extent of aortic coverage due to the concomitant risk of spinal cord ischemia. In Type B dissection, the PETTICOAT (Provisional Extension To Induce Complete Attachment) technique, which entails stent graft coverage of the primary intimal tear followed by bare metal stent placement distally, may improve true lumen caliber and promote false lumen thrombosis without increasing the risk of spinal cord ischemia, as intercostal branches remain perfused through the bare metal stents. The technique of hybrid arch with surgical creation of a Dacron landing zone covering a stent graft in the proximal descending aorta and bare metal stents in the thoraco-abdominal aorta is a promising concept in the treatment of ATAAD. PMID:29657948

Endoscopic guided single self-linking silicone stent in pediatric external dacryocystorhinostomy.

PubMed

Ali, Mohammad Javed; Gupta, Himika; Naik, Milind N; Honavar, Santosh G

2013-09-01

To study the efficacy of a new technique of single self-linking silicone stent exclusively in pediatric external dacryocystorhinostomy (DCR) and to report the new use and advantages of endoscopic guidance for the same. Prospective interventional case series, including 11 eyes of ten patients with nasolacrimal duct obstruction. Data collected included demographic data, clinical presentation, laterality, status of lids and puncta, syringing findings, probing interpretations, types and duration of intubation. Consecutive pediatric patients with post-saccal obstruction who underwent an external dacryocystorhinostomy were included. Exclusion criteria included patients who had undergone a DCR in the past by any route via external, endonasal or transcanalicular. Primary outcome measures were stent retention and ease of stent removal. Secondary outcome measures were anatomic patency of the passage and resolution of symptoms. There were three male and seven female patients. Mean age was 9.4 years (range 6-15). A total of 11 procedures were carried out. Following placement of self-linked stents, the removal was done at a mean duration of 13.2 weeks (range:12-16 weeks). None of the patients had a stent prolapse during this period. All stents were removed in the outpatient without the use of general anesthesia with minimal endoscopic guidance. A minimum follow-up of three months following removal was considered for final analysis. Follow-up ranged from three months to six months after tube removal. The anatomical and functional success rate was 91%. There was one anatomical failure three months following tube removal and the remaining patients were free of symptoms at the last follow-up. Self-linking stents are a useful modality in pediatric patients not only to prevent stent prolapse but also to allow easy removal with minimum discomfort. Endoscopic guidance is a useful addition to this technique.

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.

Initial experience with a new biodegradable airway stent in children: Is this the stent we were waiting for?

PubMed

Antón-Pacheco, Juan L; Luna, Carmen; García, Enrique; López, María; Morante, Rocío; Tordable, Cristina; Palacios, Alba; de Miguel, Mónica; Benavent, Isabel; Gómez, Andrés

2016-06-01

To report our experience with a new type of biodegradable airway stent in the setting of severe tracheobronchial obstruction in children. We conducted a retrospective and prospective (since June 2014) study of pediatric patients with severe airway obstruction treated with biodegradable stents in our institution between 2012 and 2015. The following data were collected: demographics, indication for stenting, bronchoscopic findings, insertion technique complications, clinical outcome, stent related complications, re-stenting, and time of follow-up. Thirteen custom-made polydioxanone stents were placed in four infants (mean age, 4 months) with severe tracheobronchial obstruction: tracheomalacia (two patients), bronchomalacia (1), and diffuse tracheal stenosis (1). All the stents were bronchoscopically inserted uneventfully. Immediate and maintained clinical improvement was observed in every case. No major stent related complications have occurred and only mild or moderate granulation tissue was observed during surveillance bronchoscopy. Two patients required repeated stenting as expected. All the patients are alive and in a good respiratory condition with a follow-up ranging from 5 to 40 months. Biodegradable airway stents seem to be safe, effective, and cause fewer complications than other types of stents. They can be an alternative to the classic metallic or plastic stents for severe tracheal stenosis or malacia in small children. More experience is needed in order to establish the definite clinical criteria for their use in pediatric patients. Pediatr Pulmonol. 2016;51:607-612. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

Endovascular Therapy in Trauma

DTIC Science & Technology

2014-11-23

patients. The use of endovascu- lar techniques in trauma can be considered in three broad categories: (1) large-vessel repair (e.g. covered stent repair...covered stent grafts, and coils and other thrombotic adjuncts. Devices from these categories are introduced over a wire at the access site through...technique or some form of distal aortic perfusion [6]. The use of stent grafts to manage tho- racic aortic trauma stemmed from favorable observations

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.

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.

Correction of nasal deformity in infants with unilateral cleft lip and palate using multiple digital techniques.

PubMed

Zheng, Yaqi; Zhang, Dapeng; Qin, Tian; Wu, Guofeng

2016-06-01

Presurgical correction of severe nasal deformities before cheiloplasty is often recommended for infants with cleft lip and palate. This article describes an approach for the computer-aided design and fabrication of a nasal molding stent. A 3-dimensional photogrammetric system was used to obtain the shape information of the nosewing that was then built as the nostril support for the nasal molding stent. The stent was fabricated automatically with a rapid prototyping machine. This technique may be an alternative approach to presurgical nasal molding in the clinic. Moreover, the patient's nasal morphology can be saved as clinical data for future study. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Renal angioplasty and stenting: is it still indicated after ASTRAL and STAR studies?

PubMed

Henry, M; Benjelloun, A; Henry, I; Polydorou, A; Hugel, M

2010-10-01

A renal artery stenosis (RAS) is common among patients with atherosclerosis, up to a third of patients undergoing cardiac catheterization. Fibromuscular dysplasia is the next cause of RAS, commonly found in young women. Atherosclerosis RAS generally progresses overtime and is often associated with loss of renal mass and worsening renal function (RF). Percutaneous renal artery stent placement is the preferred method of revascularization for hemodynamically significant RAS according to ACC and AHA guidelines. Several randomized trials have shown the superiority of endovascular procedures to medical therapy alone. However, two studies ASTRAL and STAR studies were recently published and did not find any difference between renal stenting and medical therapy. But these studies have a lot of limitations and flaws as we will discuss (poor indications, poor results, numerous complications, failures, poor technique, inexperienced operators, ecc.). Despite these questionable studies, renal stenting keeps indications in patients with: uncontrolled hypertension; ischemic nephropathy; cardiac disturbance syndrome (e.g. "flash" pulmonary edema, uncontrolled heart failure or uncontrolled angina pectoris); solitary kidney. To improve the clinical response rates, a better selection of the patients and lesions is mandatory with: good non-invasive or invasive imaging; physiologic lesion assessment using transluminal pressure gradients; measurements of biomarkers (e.g., BNP); fractional flow reserve study. A problem remains after renal angioplasty stenting, the deterioration of the RF in 20-30% of the patients. Atheroembolism seems to play an important role and is probably the main cause of this R.F deterioration. The use of protection devices alone or in combination with IIb IIa inhibitors has been proposed and seems promising as shown in different recent reports. Renal angioplasty and stenting is still indicated but we need: a better patient and lesion selection; improvements in techniques and maybe the use of protection devices to reduce the risk of RF deterioration after renal stenting.

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

Dose perturbation due to the presence of a prostatic urethral stent in patients receiving pelvic radiotherapy: an in vitro study.

PubMed

Gez, E; Cederbaum, M; Yachia, D; Bar-Deroma, R; Kuten, A

1997-01-01

Temporary metallic intraprostatic stent is a new alternative treatment for patients with urinary obstructive syndrome caused by prostate cancer. Definitive radiotherapy is a treatment of choice for localized prostate cancer. This study evaluates in vitro the effect of a urethral intraprostatic metallic stent on the dose absorbed by the surrounding tissue. The study was designed to mimic the conditions under which the prostatic stent is placed in the body during pelvic irradiation. A urethral stent composed of a 50% nickel-50% titanium alloy (Uracoil-InStent) was imbedded in material mimicking normal tissue (bolus) at a simulated body depth of 10 cm. The distribution of the absorbed dose of irradiation was determined by film dosimetry using Kodak X-Omat V film. Irradiation was done in a single field at the isocenter of a 6 MV linear accelerator with a field size of 7 x 7 cm. The degree of film blackening was in direct proportion to the absorbed dose. The measurements showed an increase in dose of up to 20% immediately before the stent and a decrease of up to 18% immediately after the stent. These changes occurred within a range of 1-3 mm from both sides of the stent. In practice, irradiation in prostate cancer is given by two pairs of opposed co-axial fields; a total of four fields (Box Technique). The dose perturbations are partly cancelled in a pair of opposed beams resulting in a net variation of +/- 4%; therefore, the presence of the intraprostatic stent should not influence radiotherapy planning for prostate cancer.

Culotte stenting for coronary bifurcation lesions with 2nd and 3rd generation everolimus-eluting stents: the CELTIC Bifurcation Study.

PubMed

Walsh, Simon J; Hanratty, Colm G; Watkins, Stuart; Oldroyd, Keith G; Mulvihill, Niall T; Hensey, Mark; Chase, Alex; Smith, Dave; Cruden, Nick; Spratt, James C; Mylotte, Darren; Johnson, Tom; Hill, Jonathan; Hussein, Hafiz M; Bogaerts, Kris; Morice, Marie-Claude; Foley, David P

2018-05-24

The aim of this study was to provide contemporary outcome data for patients with de novo coronary disease and Medina 1,1,1 lesions who were treated with a culotte two-stent technique, and to compare the performance of two modern-generation drug-eluting stent (DES) platforms, the 3-connector XIENCE and the 2-connector SYNERGY. Patients with Medina 1,1,1 bifurcation lesions who had disease that was amenable to culotte stenting were randomised 1:1 to treatment with XIENCE or SYNERGY DES. A total of 170 patients were included. Technical success and final kissing balloon inflation occurred in >96% of cases. Major adverse cardiovascular or cerebrovascular events (MACCE: a composite of death, myocardial infarction [MI], cerebrovascular accident [CVA] and target vessel revascularisation [TVR]) occurred in 5.9% of patients by nine months. The primary endpoint was a composite of death, MI, CVA, target vessel failure (TVF), stent thrombosis and binary angiographic restenosis. At nine months, the primary endpoint occurred in 19% of XIENCE patients and 16% of SYNERGY patients (p=0.003 for non-inferiority for platform performance). MACCE rates for culotte stenting using contemporary everolimus-eluting DES are low at nine months. The XIENCE and SYNERGY stents demonstrated comparable performance for the primary endpoint.

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.

Nanomedicine for the reduction of the thrombogenicity of stent coatings

PubMed Central

Karagkiozaki, Varvara C; Logothetidis, Stergios D; Kassavetis, Spyridon N; Giannoglou, George D

2010-01-01

The treatment of patients with drug-eluting stents (DES) continues to evolve with the current emergence of DES technology that offers a combination of pharmacological and mechanical approaches to prevent arterial restenosis. However, despite the promising short-term and mid-term outcomes of DES, there are valid concerns about adverse clinical effects of late stent thrombosis. In this study, we present an example of how nanomedicine can offer solutions for improving stent coating manufacturing, by producing nanomaterials with tailored and controllable properties. The study is based on the exploitation of human platelets response towards carbon-based nanocoatings via atomic force microscope (AFM). AFM can facilitate the comprehensive analysis of platelets behavior onto stent nanocoatings and enable the study of thrombogenicity. Platelet-rich plasma from healthy donors was used for the real-time study of biointerfacial interactions. The carbon nanomaterials were developed by rf magnetron sputtering technique under controllable deposition conditions to provide favorable surface nanotopography. It was shown that by altering the surface topography of nanocoatings, the activation of platelets can be affected, while the carbon nanocoatings having higher surface roughness were found to be less thrombogenic in terms of platelets adhesion. This is an actual solution for improving the stent coating fabrication. PMID:20463940

Current Status of Interventional Radiology Treatment of Infrapopliteal Arterial Disease

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

Rand, T., E-mail: thomas.rand@wienkav.at; Uberoi, R.

2013-06-15

Treatment of infrapopliteal arteries has developed to a standard technique during the past two decades. With the introduction of innovative devices, a variety of techniques has been created and is still under investigation. Treatment options range from plain balloon angioplasty (POBA), all sorts of stent applications, such as bare metal, balloon expanding, self-expanding, coated and drug-eluting stents, and bio-absorbable stents, to latest developments, such as drug-eluting balloons. Regarding the scientific background, several prospective, randomized studies with relevant numbers of patients have been (or will be) published that are Level I evidence. In contrast to older studies, which primarily were basedmore » mostly on numeric parameters, such as diameters or residual stenoses, more recent study concepts focus increasingly on clinical features, such as amputation rate improvement or changes of clinical stages and quality of life standards. Although it is still not decided, which of the individual techniques might be the best one, we can definitely conclude that whatever treatment of infrapopliteal arteries will be used it is of substantial benefit for the patient. Therefore, the goal of this review is to give an overview about the current developments and techniques for the treatment of infrapopliteal arteries, to present clinical and technical results, to weigh individual techniques, and to discuss the recent developments.« less

[Brief history of interventional radiology].

PubMed

Tang, Zhenliang; Jia, Aiqin; Li, Luoyun; Li, Chunyu

2014-05-01

In 1923, angiography was first successively used for the human body. In 1953, a Swedish doctor Sven-Ivar Seldinger pioneered the Seldinger technique, which laid down the foundation of interventional radiology. In 1963, Charles Dotter first proposed the idea of interventional radiology. In 1964, Charles Dotter opened a new era of percutaneous angioplasty through accidental operation, marking the formation of interventional radiology. On this basis, the techniques of balloon catheter dilation and metal stent implantation was developed. Endovascular stent was proposed in 1969. In 1973, the percutaneous angioplasty has been a breakthrough with the emergence of soft double-lumen balloon catheter. Percutaneous coronary angioplasty is applied in 1977. Since the 1990s, balloon angioplasty relegated to secondary status with the emergence of metal stent. Currently, endovascular stent have entered a new stage with the emergence of temporary stent and stent grafts and biological stent. Transcatheter arterial embolization had been one of the most important basic techniques for interventional radiology since 1965, it had also been a corresponding development with the improvement of embolic agents and catheter technology for the treatment of diseases now. Transjugular intrahepatic portosystemic stent-shunt is a comprehensive interventional radiology technology since 1967, in which the biliary system can be reached through a jugular vein, and the improvement appeared with balloon expandable stent in 1986.Since 1972, non-vascular interventional techniques was another important branch of interventional radiology. Currently, it is applied in the diagnosis and treatment of many diseases of the internal organs like the pancreas, liver, kidney, spinal cord, Fallopian tubes, esophagus and other organs. In 1973, Chinese radiologist first conducted the angiography test. Interventional radiology was introduced into China in the 1980s, it was readily developed through the sponsoring of training class (1981) and academic conferences (1986). Along with the return of the overseas scholars, the gap in the interventional diagnosis and treatment technology between China and the world has been narrowing since the 1990s.

Routine short-term ureteral stent in living donor renal transplantation: introduction of a simple stent removal technique without using anesthesia and cystoscope.

PubMed

Dong, J; Lu, J; Zu, Q; Yang, S; Sun, S; Cai, W; Zhang, L; Zhang, X

2011-12-01

We evaluated routine short-time insertion of ureteral stent in living donor renal transplant at a single center. It was easy to remove the stent without cystoscopy and anesthesia. Between October 2007 and July 2010, a single surgeon performed 76 living donor renal transplantations at one institute. All recipients underwent extravesical ureteroneocystostomy with a 2-0 silk suture passed through the venting side hole of the double-J stent into the bladder; a quadruple knot prevented the suture's slippage or distraction from the stent. After removal of the indwelling catheter at 5 days posttransplantation, the 2-0 silk passed with the urinary stream within 72 hours. The double-J stent was removed at 7 to 10 (mean 8.4) days after kidney transplantation by pulling the 2-0 silk out of the urethral orifice without anesthesia or cystoscopy. There was only one case of stenosis, which was resolved by surgery. No patient developed urinary leakage. There were three episodes of urinary tract infection in 70 patients during first 6 months' follow-up. Routine short-term stenting is a safe and effective technique in living donor renal transplantation. Removal of the stent is feasible without cystoscopy or anesthesia. Copyright © 2011 Elsevier Inc. All rights reserved.

Evaluation of hemodynamics changes during interventional stent placement using Doppler optical coherence tomography

NASA Astrophysics Data System (ADS)

Vuong, Barry; Genis, Helen; Wong, Ronnie; Ramjist, Joel; Jivraj, Jamil; Farooq, Hamza; Sun, Cuiru; Yang, Victor X. D.

2015-03-01

Carotid atherosclerosis is a critical medical concern that can lead to ischemic stroke. Local hemodynamic patterns have also been associated with the development of atherosclerosis, particularly in regions with disturbed flow patterns such as bifurcations. Traditionally, this disease was treated using carotid endarterectomy, however recently there is an increasing trend of carotid artery stenting due to its minimally invasive nature. It is well known that this interventional technique creates changes in vasculature geometry and hemodynamic patterns due to the interaction of stent struts with arterial lumen, and is associated with complications such as distal emboli and restenosis. Currently, there is no standard imaging technique to evaluate regional hemodynamic patterns found in stented vessels. Doppler optical coherence tomography (DOCT) provides an opportunity to identify in vivo hemodynamic changes in vasculature using high-resolution imaging. In this study, blood flow profiles were examined at the bifurcation junction in the internal carotid artery (ICA) in a porcine model following stent deployment. Doppler imaging was further conducted using pulsatile flow in a phantom model, and then compared to computational fluid dynamics (CFD) simulation of a virtual bifurcation to assist with the interpretation of emphin vivo results.

Pull-Through Technique for Recanalization of Occluded Portosystemic Shunts (TIPS): Technical Note and Review of the Literature

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

Tanaka, Toshihiro, E-mail: toshihir@bf6.so-net.ne.jp; Guenther, Rolf W., E-mail: guenther@rad.rwth-aachen.de; Isfort, Peter, E-mail: isfort@hia.rwth-aachen.de

Transjugular intrahepatic portosystemic shunt (TIPS) dysfunction is an important problem after creation of shunts. Most commonly, TIPS recanalization is performed via the jugular vein approach. Occasionally it is difficult to cross the occlusion. We describe a hybrid technique for TIPS revision via a direct transhepatic access combined with a transjugular approach. In two cases, bare metal stents or polytetrafluoroethylene (PTFE)-covered stent grafts had been placed in TIPS tract previously, and they were completely obstructed. The tracts were inaccessible via the jugular vein route alone. In each case, after fluoroscopy or computed tomography-guided transhepatic puncture of the stented segment of themore » TIPS, a wire was threaded through the shunt and snared into the right jugular vein. The TIPS was revised by balloon angioplasty and additional in-stent placement of PTFE-covered stent grafts. The patients were discharged without any complications. Doppler sonography 6 weeks after TIPS revision confirmed patency in the TIPS tract and the disappearance of ascites. We conclude that this technique is feasible and useful, even in patients with previous PTFE-covered stent graft placement.« less

Stent-over-sponge (SOS): a novel technique complementing endosponge therapy for foregut leaks and perforations.

PubMed

Valli, Piero V; Mertens, Joachim C; Kröger, Arne; Gubler, Christoph; Gutschow, Christian; Schneider, Paul M; Bauerfeind, Peter

2018-02-01

 Endoluminal vacuum therapy (EVT) has evolved as a promising option for endoscopic treatment of foregut wall injuries in addition to the classic closure techniques using clips or stents. To improve vacuum force and maintain esophageal passage, we combined endosponge treatment with a partially covered self-expandable metal stent (stent-over-sponge; SOS).  Twelve patients with infected upper gastrointestinal wall defects were treated with the SOS technique.  Indications for SOS were anastomotic leakage after surgery (n = 11) and chronic foregut fistula (n = 1). SOS treatment was used as a first-line treatment in seven patients with a success rate of 71.4 % (5/7) and as a second-line treatment after failed previous EVT treatment in five patients (success rate 80 %; 4/5). Overall, SOS treatment was successful in 75 % of patients (9/12). No severe adverse events occurred. CONCLUSION : SOS is an effective method to treat severely infected foregut wall defects in patients where EVT has failed, and also as a first-line treatment. Comparative prospective studies are needed to confirm our preliminary results. © Georg Thieme Verlag KG Stuttgart · New York.

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

Ureteric catheterization via an ileal conduit: technique and retrieval of a JJ stent.

PubMed

Wah, T M; Kellett, M J

2004-11-01

Retrograde ureteric catheterization of a patient with an ileal conduit is difficult, because guide wires and catheters coil in the conduit. A modified loopogram, using a Foley catheter as a fulcrum through which catheters can be advanced to the ureteric anastomosis, is described. This technique was used to remove a JJ stent, which had been inserted previously across a stricture in one ureter, the stent crossing from one kidney to the other.

Anatomic bifurcated reconstruction of chronic bilateral innominate-superior vena cava occlusion using the Y-stenting technique.

PubMed

Amin, Parth; Sharafuddin, Mel J; Laurich, Chad; Nicholson, Rachael M; Sun, Raphael C; Roh, Simon; Kresowik, Timothy F; Sharp, William J

2012-02-01

This article presents the case of a 42-year-old man who presented with superior vena cava (SVC) syndrome due to fibrosing mediastinitis with multiple failed attempts at recanalization. We initially treated him with unilateral sharp needle recanalization of the right innominate vein into the SVC stump followed by stenting. Although his symptoms improved immediately, they did not completely resolve. Six months later, he returned with worsening symptoms, and venography revealed in-stent restenosis. The patient requested simultaneous treatment on the left side. The right stent was dilated, and a 3-cm-long occlusion of the left innominate vein was recanalized, again using sharp needle technique, homing into the struts of the right-sided stent. Following fenestration of the stent, a second stent was deployed from the left side into the SVC, and the two Y limbs were sequentially dilated to allow a true bifurcation anatomy (figure). The patient had complete resolution of his symptoms and continues to do well 6 months later. Copyright © 2012 Annals of Vascular Surgery Inc. Published by Elsevier Inc. All rights reserved.

Retrograde exchange of heavily encrusted ureteric stents via the ileal conduit: a technical report.

PubMed

Tapping, Charles Ross; Boardman, Phil

2014-02-01

We describe two cases of retrograde ureteric stent exchange of heavily encrusted ureteric stents (JJ) via tortuous ileal conduits. The blocked ureteric stents were snared from inside the conduit so they could be accessed and a wire inserted. The lumens of the stents were unblocked with a wire but the stents could not be withdrawn due to heavy encrustation of the ureteric stent in the renal pelvis. A stiff wire was inserted to provide support and a 9 French peel away sheath was used to remove the encrustations allowing the stents to be withdrawn and exchanged. This is a safe and successful technique allowing ureteric stents to be removed when heavily encrusted. © 2013 The Royal Australian and New Zealand College of Radiologists.

Robot-assisted laparoscopic pyeloureterostomy in infants with duplex systems and upper pole hydronephrosis: Variations in double-J ureteral stenting techniques.

PubMed

Baek, Minki; Au, Jason; Huang, Gene O; Koh, Chester J

2017-04-01

We describe our experience with robot-assisted laparoscopic (RAL) pyeloureterostomy in infants with duplex systems and upper pole hydronephrosis with an emphasis on the various double J (DJ) ureteral stent placement techniques. We used our RAL pyeloureterostomy technique in two female infants with duplex systems and upper pole hydronephrosis. For case 1, we introduced the DJ stent and placed it in the recipient lower pole ureter during the robotic operation in an antegrade fashion. For case 2, we inserted the DJ stent during retrograde pyelography prior to the robotic procedure in a retrograde fashion, and the proximal portion of the stent was placed across the anastomosis into the upper pole renal pelvis. Postoperatively, each of the patients were discharged on postoperative day 1 without complications. The postoperative renal ultrasound at 3 months demonstrated marked improvement of the right upper pole hydronephrosis in both patients. RAL pyeloureterostomy represents a minimally invasive option for upper tract reconstruction of duplex systems with upper pole hydronephrosis in infants. The DJ stent can be placed at the beginning or during the procedure. The stent can be placed in the lower pole ureter or across the anastomosis into the upper pole renal pelvis. Copyright © 2017 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved.

Crossing Y-stent technique with dual open-cell stents for coiling of wide-necked bifurcation aneurysms.

PubMed

Ko, Jun Kyeung; Han, In Ho; Cho, Won Ho; Choi, Byung Kwan; Cha, Seung Heon; Choi, Chang Hwa; Lee, Sang Weon; Lee, Tae Hong

2015-05-01

Double stenting in a Y-configuration is a promising therapeutic option for wide-necked cerebral aneurysms not amenable to reconstruction with a single stent. We retrospectively evaluated the efficacy and safety of the crossing Y-stent technique for coiling of wide-necked bifurcation aneurysms. By collecting clinical and radiological data we evaluated from January 2007 through December 2013, 20 wide-necked bifurcation aneurysms. Twelve unruptured and eight ruptured aneurysms in 20 patients were treated with crossing Y-stent-assisted coiling. Aneurysm size and neck size ranged from 3.2 to 28.2mm (mean 7.5mm) and from 1.9 to 9.1mm (mean 4.5mm). A Y-configuration was established successfully in all 20 patients. All aneurysms were treated with a pair of Neuroform stents. The immediate angiographic results were total occlusion in 17 aneurysms, residual neck in two, and residual sac in one. Peri-operative morbidity was only 5%. Fifteen of 18 surviving patients underwent follow-up conventional angiography (mean, 10.9 months). The result showed stable occlusion in all 15 aneurysms and asymptomatic in-stent occlusion in one branch artery. At the end of the observation period (mean, 33.5 months), all 12 patients without subarachnoid hemorrhage had excellent clinical outcomes (mRS 0), except one (mRS 2). Of eight patients with subarachnoid hemorrhage, four remained symptom free (mRS 0), while the other four had were dependent or dead (mRS score, 3-6). In this report on 20 patients, crossing Y-stent technique for coiling of wide-necked bifurcation aneurysms showed a good technical safety and favorable clinical and angiographic outcome. Copyright © 2015. Published by Elsevier B.V.

High-Resolution C-Arm CT and Metal Artifact Reduction Software: A Novel Imaging Modality for Analyzing Aneurysms Treated with Stent-Assisted Coil Embolization.

PubMed

Yuki, I; Kambayashi, Y; Ikemura, A; Abe, Y; Kan, I; Mohamed, A; Dahmani, C; Suzuki, T; Ishibashi, T; Takao, H; Urashima, M; Murayama, Y

2016-02-01

Combination of high-resolution C-arm CT and novel metal artifact reduction software may contribute to the assessment of aneurysms treated with stent-assisted coil embolization. This study aimed to evaluate the efficacy of a novel Metal Artifact Reduction prototype software combined with the currently available high spatial-resolution C-arm CT prototype implementation by using an experimental aneurysm model treated with stent-assisted coil embolization. Eight experimental aneurysms were created in 6 swine. Coil embolization of each aneurysm was performed by using a stent-assisted technique. High-resolution C-arm CT with intra-arterial contrast injection was performed immediately after the treatment. The obtained images were processed with Metal Artifact Reduction. Five neurointerventional specialists reviewed the image quality before and after Metal Artifact Reduction. Observational and quantitative analyses (via image analysis software) were performed. Every aneurysm was successfully created and treated with stent-assisted coil embolization. Before Metal Artifact Reduction, coil loops protruding through the stent lumen were not visualized due to the prominent metal artifacts produced by the coils. These became visible after Metal Artifact Reduction processing. Contrast filling in the residual aneurysm was also visualized after Metal Artifact Reduction in every aneurysm. Both the observational (P < .0001) and quantitative (P < .001) analyses showed significant reduction of the metal artifacts after application of the Metal Artifact Reduction prototype software. The combination of high-resolution C-arm CT and Metal Artifact Reduction enables differentiation of the coil mass, stent, and contrast material on the same image by significantly reducing the metal artifacts produced by the platinum coils. This novel image technique may improve the assessment of aneurysms treated with stent-assisted coil embolization. © 2016 by American Journal of Neuroradiology.

The integrated place of tracheobronchial stents in the multidisciplinary management of large post-pneumonectomy fistulas: our experience using a novel customised conical self-expandable metallic stent.

PubMed

Dutau, Hervé; Breen, David Patrick; Gomez, Carine; Thomas, Pascal Alexandre; Vergnon, Jean-Michel

2011-02-01

Stump dehiscence after pneumonectomy is a cause of morbidity and mortality in patients treated for non-small-cell lung carcinoma. Surgical repair remains the treatment of choice but can be postponed or contraindicated. Bronchoscopic techniques may be an option with curative intent or as a bridge towards definitive surgery. The aim of the study is to evaluate the efficacy and the outcome of a new customised covered conical self-expandable metallic stent in the management of large bronchopleural fistulas complicating pneumonectomies. A case series using chart review of non-operable patients presenting with large bronchopleural fistulas (>6mm) post-pneumonectomies as a definitive treatment with curative intent for non-small-cell lung carcinomas and requiring the use of a dedicated conical shaped stent in two tertiary referral centres. Seven patients presenting large post-pneumonectomy fistulas (between 6 and 12 mm) were included. Cessation of the air leak and clinical improvement was achieved in all the patients after stent placement. Stent-related complications (two migrations and one stent rupture) were successfully managed using bronchoscopic techniques in two patients and surgery in one. Mortality, mainly related to overwhelming sepsis, was 57%. Delayed definitive surgery was achieved successfully in three patients (43%). This case series assesses the short-term clinical efficacy of a new customised covered conical self-expandable metallic stent in the multidisciplinary management of large bronchopleural fistulas complicating pneumonectomies in patients deemed non-operable. Long-term benefits are jeopardised by infectious complications. Copyright © 2010 European Association for Cardio-Thoracic Surgery. Published by Elsevier B.V. All rights reserved.

Endoscopic control of enterocutaneous fistula by dual intussuscepting stent technique.

PubMed

Melich, George; Pai, Ajit; Balachandran, Banujan; Marecik, Slawomir J; Prasad, Leela M; Park, John J

2016-09-01

Large high-output enterocutaneous fistulas pose great difficulties, especially in the setting of recent surgery and compromised skin integrity. This video demonstrates a new technique of endoscopic control of enterocutaneous fistula by using two covered overlapping stents. In brief, the two stents are each inserted endoscopically, one proximal, and the other distal to the fistula with 2 cm of each stent protruding cutaneously. Following this, the proximal stent is crimped and intussuscepted into the distal stent with an adequate overlap. A prolene suture is passed through the anterior wall of both stents to prevent migration. The two stents used were evolution esophageal stents-10 cm long, fully covered, double-flared with non-flared and flared diameters being 20 and 25 mm, respectively (product number EVO-FC-20-25-10-E, Cook Medical, Bloomington, IN, USA). The patient featured in this video developed a high-output enterocutaneous fistula proximal to a loop ileostomy, which was created following a small bowel leak after a curative surgery for bladder cancer. Using the technique featured in this video (schematic depicted in Fig. 1), the patient was nutritionally optimized with oral feeds from albumin of 0.9-3.4 g/dl within 2 months despite prior failure to achieve nutrition optimization and adequate skin protection with combination of oral and/or parenteral nutrition. Three months after stenting, following nutritional optimization and improvement of skin coverage, definitive procedure consisted of uncomplicated fistula resection with primary stapled side-to-side functional end-to-end anastomosis. The stents were not completely incorporated into the mucosa and were rather easily pulled through the residual fistula opening just prior to the surgery. Only minimal fibrosis was noted and less than 20 cm of involved small bowel needed to be resected. Had the fistula have closed completely, the options would have included (1) proceeding to bowel resection with removal of the stents regardless of closure, or (2) cutting the securing prolene stitch and observation. Considering the placement of the stents in mid-small bowel, their endoscopic retrieval would have been difficult unless they were to migrate into the colon. Although a prior attempt at managing an enterocutaneous fistula with a stent deployed through a colostomy site was previously reported [1], there is no published account of bridging an enterocutaneous fistula with overlapping endoscopic stents through the fistula itself. This video serves as a proof of concept for temporizing enterocutaneous fistulas with endoscopic stenting.

Management of embedded metallic stents used in the treatment of grades III and IV subglottic, and upper tracheal stenosis in adults.

PubMed

Sendi, Khalil; Al-Khatib, Talal; Ahmed, Duha G; Tonkul, Al-Baraa

2014-11-01

The aim of this study was to evaluate the post-operative complications of using balloon-expandable metallic stents in treatment of benign, major subglottic and tracheal stenosis in adult patients whom conventional therapy has failed and to demonstrate how to deal with these complications in the long run. A retrospective review of five cases; adlut patiets with benign, major subglottic and upper tracheal stenosis whom were treated with balloon expandable metallic stents at King Abdulaziz University Hospital, in the years between 2008 and 2013. Granulation tissue formed in five of the four cases and restenosis occurred. Other complications encountered were stent infection and dislodgment. The complications were managed by removing the stents surgically via a laryngofissure incision and required the placement of a Montgomery T-tube. Managing the restenosis due to granulation tissue formation around the metallic stents is best achieved by removing the embedded metallic stents surgically via open technique and then by placement of a Montgomery T-tube as a bridging option to successful decannulation. Open surgical procedures remain the mainstay treatment for advanced airway stenosis.

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.

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

Palena, Luis Mariano, E-mail: marianopalena@hotmail.com; Cester, Giacomo; Manzi, Marco

In-stent reocclusion is a frequent complication of endovascular treatment and stenting, especially in the superficial femoral artery. Neointimal hyperplasia is the main cause of this problem, but in many cases, it occurs as a result of the presence of stent strut fractures. The two treatment options are endovascular and surgical intervention. The effectiveness of endovascular interventions in patients with critical limb ischemia has been well established, but in some cases, crossing the occluded stent is difficult. We describe a new technique to recanalize long in-stent superficial femoral artery occlusions characterized by direct stent puncture, followed by retrograde-antegrade recanalization after antegrademore » failures.« less

[Value of the optical coherence tomography in the treatment guided of the stent failure. Case report].

PubMed

Macías, Enrico; Tellez, Alejandro; Ochoa, Jorge; Ortíz, José E

2014-01-01

Since the advent of bare metal and drug-eluting stents, the surgical revascularization have declined considerably, however the thrombosis and in-stent restenosis are important complications of these devices. There are several factors that predispose to thrombosis and in-stent restenosis. Conventional angiography has serious limitations to determine the causes of stent failure. Optical coherence tomography is a very sensitive technique to determine the cause of thrombosis and in-stent restenosis. Copyright © 2013 Instituto Nacional de Cardiología Ignacio Chávez. Published by Masson Doyma México S.A. All rights reserved.

Automatic segmentation of the wire frame of stent grafts from CT data.

PubMed

Klein, Almar; van der Vliet, J Adam; Oostveen, Luuk J; Hoogeveen, Yvonne; Kool, Leo J Schultze; Renema, W Klaas Jan; Slump, Cornelis H

2012-01-01

Endovascular aortic replacement (EVAR) is an established technique, which uses stent grafts to treat aortic aneurysms in patients at risk of aneurysm rupture. Late stent graft failure is a serious complication in endovascular repair of aortic aneurysms. Better understanding of the motion characteristics of stent grafts will be beneficial for designing future devices. In addition, analysis of stent graft movement in individual patients in vivo can be valuable for predicting stent graft failure in these patients. To be able to gather information on stent graft motion in a quick and robust fashion, we propose an automatic method to segment stent grafts from CT data, consisting of three steps: the detection of seed points, finding the connections between these points to produce a graph, and graph processing to obtain the final geometric model in the form of an undirected graph. Using annotated reference data, the method was optimized and its accuracy was evaluated. The experiments were performed using data containing the AneuRx and Zenith stent grafts. The algorithm is robust for noise and small variations in the used parameter values, does not require much memory according to modern standards, and is fast enough to be used in a clinical setting (65 and 30s for the two stent types, respectively). Further, it is shown that the resulting graphs have a 95% (AneuRx) and 92% (Zenith) correspondence with the annotated data. The geometric model produced by the algorithm allows incorporation of high level information and material properties. This enables us to study the in vivo motions and forces that act on the frame of the stent. We believe that such studies will provide new insights into the behavior of the stent graft in vivo, enables the detection and prediction of stent failure in individual patients, and can help in designing better stent grafts in the future. Copyright © 2011 Elsevier B.V. All rights reserved.

In vitro simulator with numerical stress analysis for evaluation of stent-assisted coiling embolization in cerebral aneurysm treatments.

PubMed

Shi, Chaoyang; Kojima, Masahiro; Tercero, Carlos; Najdovski, Zoran; Ikeda, Seiichi; Fukuda, Toshio; Arai, Fumihito; Negoro, Makoto

2014-12-01

There are several complications associated with Stent-assisted Coil Embolization (SACE) in cerebral aneurysm treatments, due to damaging operations by surgeons and undesirable mechanical properties of stents. Therefore, it is necessary to develop an in vitro simulator that provides both training and research for evaluating the mechanical properties of stents. A new in vitro simulator for three-dimensional digital subtraction angiography was constructed, followed by aneurysm models fabricated with new materials. Next, this platform was used to provide training and to conduct photoelastic stress analysis to evaluate the SACE technique. The average interaction stress increasingly varied for the two different stents. Improvements for the Maximum-Likelihood Expectation-Maximization method were developed to reconstruct cross-sections with both thickness and stress information. The technique presented can improve a surgeon's skills and quantify the performance of stents to improve mechanical design and classification. This method can contribute to three-dimensional stress and volume variation evaluation and assess a surgeon's skills. Copyright © 2013 John Wiley & Sons, Ltd.

Long-term outcomes of a newly developed hybrid metal stent for EUS-guided biliary drainage (with videos).

PubMed

Cho, Dong Hui; Lee, Sang Soo; Oh, Dongwook; Song, Tae Jun; Park, Do Hyun; Seo, Dong Wan; Lee, Sung Koo; Kim, Myung-Hwan

2017-05-01

Although fully covered self-expandable metal stents (FCSEMSs) have been commonly used for EUS-guided biliary drainage (EUS-BD), FCSEMS migration is a main limitation of this procedure. In the present study we evaluated the technical and clinical success rates, adverse events, and long-term outcomes of a newly developed hybrid stent that has been customized for EUS-BD. From September 2011 to May 2015, 54 consecutive patients with biliary obstruction were enrolled in this prospective, observational study. These patients were candidates for alternative BD techniques because of failed ERCP. The hybrid metal stent used for EUS-BD in this study was partially covered, had anchoring flaps, and is commercially available in Korea. EUS-guided hepaticogastrostomy (EUS-HGS) was performed in 21 patients and EUS-guided choledochoduodenostomy (EUS-CDS) in 33 patients. The technical and clinical success rates of EUS-BD were 100% (54/54) and 94.4% (51/54), respectively. Immediate adverse events developed after EUS-BD in 9 patients (16.6%; cholangitis in 3, bleeding in 2, self-limited pneumoperitoneum in 3, and abdominal pain in 1). Proximal or distal stent migration was not observed during the follow-up period (median, 148.5 days; IQR, 79.7-244), and the mean stent patency duration was 166.3 days and 329.1 days in the EUS-HGS and EUS-CDS groups, respectively. EUS-BD with the hybrid metal stent is technically feasible and can effectively treat biliary obstruction after failed ERCP. EUS-BD with the hybrid metal stent can reduce stent-related adverse events, especially stent migration. Copyright © 2017 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc. All rights reserved.

A Bumpy and Winding but Right Path to Domestic Drug-Eluting Coronary Stents

PubMed Central

Cho, Jae Yeong; Ahn, Youngkeun

2013-01-01

Restenosis and stent thrombosis remain major concerns after percutaneous coronary intervention for the treatment of coronary artery disease. The present review was undertaken in order to highlight the various coronary stents that have been investigated in our Heart Research Center, and how far we have come from the first heparin-coated stent first used in the late 1990s. Thereafter, from the abciximab-coated stent to the current gene-delivery stent and other newer agents, our group has applied a range of techniques in this field. However, in groups similar to ours, the restenosis rates of such stents are still high for second-generation drug-eluting stents (DESs). Moreover, our nation imports almost all of these types of stents from other countries. Thus, we need to develop domestic coronary stents. Research into newer DESs are warranted in Korea so as to achieve improved safety and efficacy outcomes. PMID:24255648

Development of a static bioactive stent prototype and dynamic aneurysm-on-a-chip(TM) model for the treatment of aneurysms

NASA Astrophysics Data System (ADS)

Reece, Lisa M.

Aneurysms are pockets of blood that collect outside blood vessel walls forming dilatations and leaving arterial walls very prone to rupture. Current treatments include: (1) clipping, and (2) coil embolization, including stent-assisted coiling. While these procedures can be effective, it would be advantageous to design a biologically active stent, modified with magnetic stent coatings, allowing cells to be manipulated to heal the arterial lining. Further, velocity, pressure, and wall shear stresses aid in the disease development of aneurysmal growth, but the shear force mechanisms effecting wound closure is elusive. Due to these factors, there is a definite need to cultivate a new stent device that will aid in healing an aneurysm in situ. To this end, a static bioactive stent device was synthesized. Additionally, to study aneurysm pathogenesis, a lab-on-a-chip device (a dynamic stent device) is the key to discovering the underlying mechanisms of these lesions. A first step to the reality of a true bioactive stent involves the study of cells that can be tested against the biomaterials that constitute the stent itself. The second step is to test particles/cells in a microfluidic environment. Therefore, biocompatability data was collected against PDMS, bacterial nanocellulose (BNC), and magnetic bacterial nanocellulose (MBNC). Preliminary static bioactive stents were synthesized whereby BNC was grown to cover standard nitinol stents. In an offshoot of the original research, a two-dimensional microfluidic model, the Aneurysm-on-a-ChipTM (AOC), was the logical answer to study particle flow within an aneurysm "sac" - this was the dynamic bioactive stent device. The AOC apparatus can track particles/cells when it is coupled to a particle image velocimetry software (PIV) package. The AOC fluid flow was visualized using standard microscopy techniques with commercial microparticles/cells. Movies were taken during fluid flow experiments and PIV was utilized to monitor.

T-Stenting-and-Small-Protrusion Technique for Bifurcation Stenoses After End-to-Side Anastomosis of Transplant Renal Artery and External Iliac Artery: Report of Two Cases

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

Chen, Yong, E-mail: cheny102@163.com; Ye, Peng, E-mail: thomas19871223@163.com; Jiang, Wen-jin, E-mail: 18653501187@163.com

Bifurcation stenoses after end-to-side anastomosis of transplant renal artery (TRA) and external iliac artery (EIA), including stenoses at the anastomosis and the iliac artery proximal to the TRA, are rare. In the present article, we report two successfully managed cases of bifurcation stenoses after end-to-side anastomosis of the TRA and EIA using the technique of T-stenting and small protrusion (TAP stenting)

Real-World Bioresorbable Vascular Scaffold Experience Compared With Second-Generation Metallic Drug-Eluting Stents in Complex Coronary Lesions.

PubMed

Okamoto, Naotaka; Ueda, Hiroshi; Yoshimura, Takahiro; Chamaria, Surbhi; Bhatheja, Samit; Vengrenyuk, Yuliya; Rabiei, Samaneh; Barrientos, Yonandy; Kapur, Vishal; Barman, Nitin; Sweeny, Joseph; Baber, Usman; Mehran, Roxana; Sharma, Samin K; Kini, Annapoorna S

2018-04-15

The aim of the study was to compare the acute outcomes of Absorb bioresorbable vascular scaffolds (BVS) and second-generation drug-eluting stent (DES) implantation in routine clinical practice. There is a paucity of data regarding BVS use in a real-world patient population. The study population comprised 40 consecutive patients who underwent percutaneous coronary intervention (PCI) with BVS implantation at a tertiary-care center in New York, New York between July and December of 2016. An optimal implantation technique including adequate lesion preparation, mandatory postdilation, and optical coherence tomography (OCT) imaging was used in all cases. De novo lesions treated with BVS were compared to lesions treated with DES matched by OCT calcium arc, scaffold/stent size, use of atherectomy device, and lesion postdilation. Acute lumen gain, minimal device area, malapposition, eccentricity, and symmetry index were assessed using OCT. We analyzed OCT images of 40 BVS cases and 40 matching DES cases from 35 and 40 patients, respectively. Compared to the DES group, the BVS group demonstrated similar acute lumen gain, minimal scaffold/stent area, eccentricity index, and symmetry index after PCI. There were fewer malapposed struts detected after BVS implantation; however, malapposition distance and length were not different between the groups. BVS implantation in a real-world patient population with optimal implantation technique resulted in similar stent expansion and better strut apposition compared to DES implantation.

Air Embolism During TEVAR: Carbon Dioxide Flushing Decreases the Amount of Gas Released from Thoracic Stent-Grafts During Deployment.

PubMed

Rohlffs, Fiona; Tsilimparis, Nikolaos; Saleptsis, Vasilis; Diener, Holger; Debus, E Sebastian; Kölbel, Tilo

2017-02-01

To investigate the amount of gas released from Zenith thoracic stent-grafts using standard saline flushing vs the carbon dioxide flushing technique. In an experimental bench setting, 20 thoracic stent-grafts were separated into 2 groups of 10 endografts. One group of grafts was flushed with 60 mL saline and the other group was flushed with carbon dioxide for 5 minutes followed by 60 mL saline. All grafts were deployed into a water-filled container with a curved plastic pipe; the deployment was recorded and released gas was measured using a calibrated setup. Gas was released from all grafts in both study groups during endograft deployment. The average amount of released gas per graft was significantly lower in the study group with carbon dioxide flushing (0.79 vs 0.51 mL, p=0.005). Thoracic endografts release significant amounts of air during deployment if flushed according to the instructions for use. Application of carbon dioxide for the flushing of thoracic stent-grafts prior to standard saline flush significantly reduces the amount of gas released during deployment. The additional use of carbon dioxide should be considered as a standard flush technique for aortic stent-grafts, especially in those implanted in proximal aortic segments, to reduce the risk of air embolism and stroke.

Newly Designed Y-configured Single-Catheter Stenting for the Treatment of Hilar-Type Nonanastomotic Biliary Strictures After Orthotopic Liver Transplantation

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

Wang Changming; Li Xuan, E-mail: lixuanbysy@163.com; Song Shibing

2012-02-15

Purpose: This study was designed to introduce our novel technique of percutaneous single catheter placement into the hilar bile ducts strictures while fulfilling the purpose of bilateral biliary drainage and stenting. We investigated the efficacy and safety of the technique for the treatment of hilar nonanastomotic biliary strictures. Methods: Ten patients who were post-orthotopic liver transplantation between July 2000 and July 2010 were enrolled in this study. Percutaneous Y-configured single-catheter stenting for bilateral bile ducts combined with balloon dilation was designed as the main treatment approach. Technical success rate, clinical indicators, complications, and recurrent rate were analyzed. Results: Technical successmore » rate was 100%. Nine of the ten patients had biochemical normalization, cholangiographic improvement, and clinical symptoms relief. None of them experienced recurrence in a median follow-up of 26 months after completion of therapy and removal of all catheters. Complications were minor and limited to two patients. The one treatment failure underwent a second liver transplantation but died of multiple system organ failure. Conclusions: Percutaneous transhepatic Y-configured single-catheter stenting into the hilar bile ducts is technically feasible. The preliminary trial of this technique combined with traditional PTCD or choledochoscopy for the treatment of hilar biliary strictures after orthotopic liver transplantation appeared to be effective and safe. Yet, further investigation is needed.« less

Biodegradable nasal stents (MgF2 -coated Mg-2 wt %Nd alloy)-A long-term in vivo study.

PubMed

Durisin, Martin; Reifenrath, Janin; Weber, Constantin M; Eifler, Rainer; Maier, Hans J; Lenarz, Thomas; Seitz, Jan-Marten

2017-02-01

Despite innovative surgical techniques and use of current frontal sinus stents from different materials, the problem of treatment failure with consecutive reoperation remains present. The aim of our study is to investigate biocompatibility, degradation kinetics, and functionality of a newly developed fluoride-coated magnesium-based nasal stent. A minipig anatomy of frontal sinus adapted design and an external surgical approach were developed and established. The functionality of the stents was evaluated endoscopically. The stent-tissue blocks were analysed after 90 and 180 days using microcomputed tomography (µ-CT), histology, scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). Functional evaluation revealed an unobstructed stent lumen in all cases. Histological analysis showed moderate mucosal hyperplasia with a mild, nonspecific inflammatory response, and nonosteoconductive effect. Rejection reactions or necrosis did not occur. The volumetric analysis of the stents showed 51% volume loss after 180 days. The EDS analysis did not detect any neodymium (Nd) in the mucosa or bone. The Mg-2 wt % Nd stents are a promising option when treating the narrow passages following paranasal sinus surgery. In particular, its good biocompatibility and good functionality facilitate the re-epithelization of these constricted passages. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 350-365, 2017. © 2015 Wiley Periodicals, Inc.

Y-shaped bilateral self-expandable metallic stent placement for malignant hilar biliary obstruction: data from a referral center for palliative care.

PubMed

Di Mitri, R; Mocciaro, F

2014-01-01

Malignant hilar strictures are a clinical challenge because of the current therapeutic approach and the poor prognosis. In recent years, self-expandable metallic stents have proven more effective than plastic stents for palliation of malignant hilar strictures, with the bilateral stent-in-stent technique registering a high success rate. We report our experience with Y-shaped endoscopic self-expandable metallic stents placement for treatment of advanced malignant hilar strictures. From April 2009 to August 2012, we prospectively collected data on patients treated with Y-shaped SEMS placement for advanced malignant hilar carcinoma. Data on technical success, clinical success, and complications were collected. Twenty patients (9 males) were treated (mean age 64.2 ± 15.3 years). The grade of malignant hilar strictures according to the Bismuth classification was II in 5 patients (25%), IIIa in 1 (5%), and IV in 14 (70%). The mean bilirubin level was 14.7 ± 4.9 mg/dL. Technical success was achieved in all patients, with a significant reduction in bilirubin levels (2.9 ± 1.7 mg/dL). One patient experienced cholangitis as early complication, while in 2 patients stent ingrowth was observed. No stents migration was recorded. There was no procedure-related mortality. At the end of the follow-up (7.1 ± 3.1 months), 13 of the 20 patients (65%) had died. Our experience confirms endoscopic bilateral self-expandable metallic stents placement with stent-in-stent technique (Y-shaped configuration) as a feasible, effective, and safe procedure for palliation of unresectable malignant hilar strictures.

CE-MRA for follow-up of aneurysms post stent-assisted coiling.

PubMed

Agid, R; Schaaf, M; Farb, Ri

2012-09-01

This study compared the accuracy of contrast-enhanced MR angiography (CE-MRA) to intra-arterial cerebral angiography (IA-DSA) for assessment of intracranial aneurysms after stent-assisted coiling and to check if the presence of a stent in the parent artery diminishes the accuracy of CE-MRA. Consecutive patients with cerebral aneurysms treated by stent-assisted coiling were evaluated retrospectively. Matching follow-up CE-MRA and IA-DSA were evaluated separately. Evaluation included the presence of aneurysmal remnant, patency and stenosis of parent artery. Twenty-seven patients with 28 aneurysms and 33 matched CE-MRA and IA-DSA studies were evaluated. Nineteen aneurysmal remnants were seen on CE-MRA and 16 on IA-DSA. CE-MRA diagnosed three aneurysmal remnants not appreciated on IA-DSA. Five other remnants were larger on CE-MRA than IA-DSA. None of the remnants were missed on CE-MRA. Parent arteries were patent on both modalities. CE-MRA showed false stenosis of the stented artery in six cases and exaggerated stenosis in two. In 18 cases, CE-MRA showed a short focal "pseudo-stenosis" where the stent's marker bands were located. This was noted whenever the stent's marker bands were located in an artery with luminal diameter ≤2 mm and was called "marker band effect". CE-MRA is an accurate technique for follow-up of aneurysms post stent-assisted coiling with excellent depiction of remnants in spite of the presence of a stent. Apparent stenosis of the stented parent artery on CE-MRA is often false or exaggerated. "Marker band effect" should be recognized as an artifact that appears when stent's marker bands are in a small artery.

Computational replication of the patient-specific stenting procedure for coronary artery bifurcations: From OCT and CT imaging to structural and hemodynamics analyses.

PubMed

Chiastra, Claudio; Wu, Wei; Dickerhoff, Benjamin; Aleiou, Ali; Dubini, Gabriele; Otake, Hiromasa; Migliavacca, Francesco; LaDisa, John F

2016-07-26

The optimal stenting technique for coronary artery bifurcations is still debated. With additional advances computational simulations can soon be used to compare stent designs or strategies based on verified structural and hemodynamics results in order to identify the optimal solution for each individual's anatomy. In this study, patient-specific simulations of stent deployment were performed for 2 cases to replicate the complete procedure conducted by interventional cardiologists. Subsequent computational fluid dynamics (CFD) analyses were conducted to quantify hemodynamic quantities linked to restenosis. Patient-specific pre-operative models of coronary bifurcations were reconstructed from CT angiography and optical coherence tomography (OCT). Plaque location and composition were estimated from OCT and assigned to models, and structural simulations were performed in Abaqus. Artery geometries after virtual stent expansion of Xience Prime or Nobori stents created in SolidWorks were compared to post-operative geometry from OCT and CT before being extracted and used for CFD simulations in SimVascular. Inflow boundary conditions based on body surface area, and downstream vascular resistances and capacitances were applied at branches to mimic physiology. Artery geometries obtained after virtual expansion were in good agreement with those reconstructed from patient images. Quantitative comparison of the distance between reconstructed and post-stent geometries revealed a maximum difference in area of 20.4%. Adverse indices of wall shear stress were more pronounced for thicker Nobori stents in both patients. These findings verify structural analyses of stent expansion, introduce a workflow to combine software packages for solid and fluid mechanics analysis, and underscore important stent design features from prior idealized studies. The proposed approach may ultimately be useful in determining an optimal choice of stent and position for each patient. Copyright © 2015 Elsevier Ltd. All rights reserved.

Iliocaval Confluence Stenting for Chronic Venous Obstructions

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

Graaf, Rick de, E-mail: r.de.graaf@mumc.nl; Wolf, Mark de, E-mail: markthewolf@gmail.com; Sailer, Anna M., E-mail: anni.sailer@mumc.nl

PurposeDifferent techniques have been described for stenting of venous obstructions. We report our experience with two different confluence stenting techniques to treat chronic bi-iliocaval obstructions.Materials and MethodsBetween 11/2009 and 08/2014 we treated 40 patients for chronic total bi-iliocaval obstructions. Pre-operative magnetic resonance venography showed bilateral extensive post-thrombotic scarring in common and external iliac veins as well as obstruction of the inferior vena cava (IVC). Stenting of the IVC was performed with large self-expandable stents down to the level of the iliocaval confluence. To bridge the confluence, either self-expandable stents were placed inside the IVC stent (24 patients, SECS group) ormore » high radial force balloon-expandable stents were placed at the same level (16 patients, BECS group). In both cases, bilateral iliac extensions were performed using nitinol stents.ResultsRecanalization was achieved for all patients. In 15 (38 %) patients, a hybrid procedure with endophlebectomy and arteriovenous fistula creation needed to be performed because of significant involvement of inflow vessels below the inguinal ligament. Mean follow-up was 443 ± 438 days (range 7–1683 days). For all patients, primary, assisted-primary, and secondary patency rate at 36 months were 70, 73, and 78 %, respectively. Twelve-month patency rates in the SECS group were 85, 85, and 95 % for primary, assisted-primary, and secondary patency. In the BECS group, primary patency was 100 % during a mean follow-up period of 134 ± 118 (range 29–337) days.ConclusionStenting of chronic bi-iliocaval obstruction shows relatively high patency rates at medium follow-up. Short-term patency seems to favor confluence stenting with balloon-expandable stents.« less

Outcome of ureteral stent placement for treatment of benign ureteral obstruction in dogs: 44 cases (2010-2013).

PubMed

Pavia, Philippa R; Berent, Allyson C; Weisse, Chick W; Neiman, Dana; Lamb, Kenneth; Bagley, Demetrius

2018-03-15

OBJECTIVE To describe the technique and short- and long-term outcomes for dogs undergoing double-pigtail ureteral stent placement for treatment of benign ureteral obstruction. DESIGN Retrospective case series. ANIMALS 44 dogs (57 ureters). PROCEDURES Medical records of dogs that underwent ureteral stenting for treatment of benign ureteral obstruction between 2010 and 2013 were reviewed. Signal-ment, history, pertinent diagnostic imaging results, endourologic and post-procedural details, duration of hospitalization, complications, and outcome (short term, 7 to 30 days; long term, > 30 days) were recorded. Ureteral stent placement was performed endoscopically, surgically, or both, with fluoroscopic guidance. RESULTS 57 ureters (44 dogs) underwent stenting because of obstructive ureterolithiasis (n = 48 [84%]), stricture (5 [9%]), or both (4 [7%]). Endoscopic or surgical techniques were successful for stent placement in 45 of 55 and 12 of 12 ureters (34/42 and 10/10 dogs), respectively. Median hospitalization time was 1 day. Median creatinine concentration was 2 mg/dL prior to stenting and 1.3 mg/dL 3 months after the procedure. Urinary tract infections were present in 26 of 44 (59%) dogs prior to stenting and in 11 of 43 dogs (26%) after stenting. One of the 44 (2%) dogs died after undergoing stenting, but the cause of death was not related to the procedure. Median follow-up time was 1,158 days (range, 3 to > 1,555 days), with 30 of 44 dogs alive at the time of last follow-up. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that ureteral stenting may be a viable option for first-line treatment of dogs with benign ureteral obstruction. However, patients should be monitored for urinary tract infection following stenting.

Therapeutic esophageal interventions for dysphagia and bleeding.

PubMed

Siersema, Peter D

2006-07-01

This article reviews the most notable results of esophageal interventions for dysphagia and bleeding published in 2005. Long-term rubber tube placement was shown to be an interesting treatment option for difficult esophageal strictures. Two studies demonstrated that only 50% of patients who had undergone pneumatic dilation for achalasia were dysphagia-free after long-term follow-up. It was shown that patients with dysphagia from esophageal cancer should be treated by intraluminal radiotherapy (brachytherapy), whereas stent placement was preferable in those with a poor prognosis. Temporary stent placement is an option in patients undergoing radiotherapy for inoperable esophageal cancer to increase the dysphagia-free period. Two studies were published on the successful use of silicone-covered plastic stents for sealing of leaks after surgery of the esophagus. The optimal treatment for bleeding varices was confirmed to be endoscopic band ligation. A meta-analysis demonstrated that adding sclerotherapy to band ligation for secondary prophylaxis of bleeding varices had no effect on clinical outcome. In 2005, new techniques for the treatment of complicated strictures were presented. In addition, expanding indications for stents were reported. Finally, endoscopic band ligation was confirmed to be the most optimal technique for the treatment of varices.

Cost-effectiveness of drug-eluting stents in patients at high or low risk of major cardiac events in the Basel Stent KostenEffektivitäts Trial (BASKET): an 18-month analysis.

PubMed

Brunner-La Rocca, Hans Peter; Kaiser, Christoph; Bernheim, Alain; Zellweger, Michael J; Jeger, Raban; Buser, Peter T; Osswald, Stefan; Pfisterer, Matthias

2007-11-03

Our aim was to determine whether drug-eluting stents are good value for money in long-term, everyday practice. We did an 18-month cost-effectiveness analysis of the Basel Stent KostenEffektivitäts Trial (BASKET), which randomised 826 patients 2:1 to drug-eluting stents (n=545) or to bare-metal stents (281). We used non-parametric bootstrap techniques to determine incremental cost-effectiveness ratios (ICERs) of drug-eluting versus bare-metal stents, to compare low-risk (> or =3.0 mm stents in native vessels; n=558, 68%) and high-risk patients (<3.0 mm stents/bypass graft stenting; n=268, 32%), and to do sensitivity analyses by altering costs and event rates in the whole study sample and in predefined subgroups. Quality-adjusted life-years (QALYs) were assessed by EQ-5D questionnaire (available in 703/826 patients). Overall costs were higher for patients with drug-eluting stents than in those with bare-metal stents (11,808 euros [SD 400] per patient with drug-eluting stents and 10,450 euros [592] per patient with bare-metal stents, mean difference 1358 euros [717], p<0.0001), due to higher stent costs. We calculated an ICER of 64,732 euros to prevent one major adverse cardiac event, and of 40,467 euros per QALY gained. Stent costs, number of events, and QALYs affected ICERs most, but unrealistic alterations would have been required to achieve acceptable cost-effectiveness. In low-risk patients, the probability of drug-eluting stents achieving an arbitrary ICER of 10,000 euros or less to prevent one major adverse cardiac event was 0.016; by contrast, it was 0.874 in high-risk patients. If used in all patients, drug-eluting stents are not good value for money, even if prices were substantially reduced. Drug-eluting stents are cost effective in patients needing small vessel or bypass graft stenting, but not in those who require large native vessel stenting.

In vitro stent lumen visualisation of various common and newly developed femoral artery stents using MR angiography at 1.5 and 3 tesla.

PubMed

Syha, R; Ketelsen, D; Kaempf, M; Mangold, S; Sixt, S; Zeller, T; Springer, F; Schick, F; Claussen, C D; Brechtel, K

2013-02-01

To evaluate stent lumen assessment of various commonly used and newly developed stents for the superficial femoral artery (SFA) using MR angiography (MRA) at 1.5 and 3 T. Eleven nitinol stents and one cobalt-chromium stent were compared regarding stent lumen visualisation using a common three-dimensional MRA sequence. Maximum visible stent lumen width and contrast ratio were analysed in three representative slices for each stent type. A scoring system for lumen visualisation was applied. Nitinol stents showed significantly better performance than the cobalt chromium stent (P < 0.05) at 1.5 and 3 T. Maximum visible stent lumen ranged between 43.4 and 95.5 %, contrast ratio between 7.2 and 110.6 %. Regarding both field strengths, seven of the nitinol stents were classified as "suitable". Three nitinol stents were "limited", and one nitinol stent and the cobalt chromium stent were "not suitable". Intraluminal loss of signal and artefacts of most of the SFA stents do not markedly limit assessment of stent lumen by MRA at 1.5 and 3 T. MRA can thus be considered a valid technique for detection of relevant in-stent restenosis. Applied field strength does not strongly influence stent lumen assessment in general, but proper choice of field strength might be helpful.

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

Engelmeier, R.L.

A technique has been described for fabrication of a radiation therapy stent that can help to stabilize the head when adjustable alignment devices are used to position a patient during radiation therapy. The technique can save time for the radiotherapist, enhance accuracy in treatment, increase patient comfort, and save the dentist time in stent fabrication.

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

Lanciego, Carlos; Miguel, Silvia De; Padilla, Manuel

The purpose of this study was to evaluate, in a prospective, single-center study, the effectiveness of Song's polyurethane stents, modified 'in-house,' in the percutaneous management of epiphora. Patients (n = 170; age range 18-83, mean = 64; 50 male, 120 female) with severe epiphora had the modified stents inserted (183 eyes/195 stents) to treat unilateral/bilateral and complete/partial obstruction of the nasolacrimal system. The etiology of the obstruction was idiopathic in 119 cases (61%) and chronic dacryocystitis in 76 (39%). The set designed by Song was used in all patients but modified by us such that the extreme end is cone-shaped.more » The original technique was slightly modified by us and the procedure was conducted on an outpatient basis. The initial technical success rate of stent placement was 97%. Resolution of epiphora was complete in 180 eyes and partial in 3. On follow-up (mean = 18 months; range: 2 days to 24 months), 165 of 195 stents (85%) remained patent. Primary patency rates at follow-up were 86%, 84%, 84%, and 79% in the first 6 months, second and third 6 months, and the present (24 months), respectively. Stents became obstructed in 30 patients, but all but 2 were easily withdrawn and 20 of these patients remained asymptomatic for a mean of 14 months (secondary patency of 67%). Following stent removal, the withdrawn stent was replaced with a new stent in the same intervention on 14 occasions. In another six cases, patency was re-established without the need of a second stent. The procedure is simple and safe, both in stent insertion as well as in mechanical de-blocking and withdrawal when occluded. Success was >80 % in the short term (1-year follow-up). Stenting failure does not preclude other treatment because with the modification that we had introduced, the extreme end of the stent becomes more accessible to mechanical de-blocking, withdrawal, and relocation. The levels of primary and secondary patencies are promising and warrant more extensive investigation.« less

Research of Customized Aortic Stent Graft Manufacture

NASA Astrophysics Data System (ADS)

Zhang, Lei; Chen, Xin; Liu, Muhan

2017-03-01

Thoracic descending aorta diseases include aortic dissection and aortic aneurysm, of which the natural mortality rate is extremely high. At present, endovascular aneurysm repair (EVAR) has been widely used as an effective means for the treatment of descending aortic disease. Most of the existing coating stents are standard design, which are unable to meet the size or structure of different patients. As a result, failure of treatment would be caused by dimensional discrepancy between stent and vessels, which could lead to internal leakage or rupture of blood vessels. Therefore, based on rapid prototyping sacrificial core - coating forming (RPSC-CF), a customized aortic stent graft manufactured technique has been proposed in this study. The aortic stent graft consists of film and metallic stent, so polyether polyurethane (PU) and nickel-titanium (NiTi) shape memory alloy with good biocompatibility were chosen. To minimum film thickness without degrading performance, effect of different dip coating conditions on the thickness of film were studied. To make the NiTi alloy exhibit super-elasticity at body temperature (37°C), influence of different heat treatment conditions on austenite transformation temperature (Af) and mechanical properties were studied. The results show that the customized stent grafts could meet the demand of personalized therapy, and have good performance in blasting pressure and radial support force, laying the foundation for further animal experiment and clinical experiment.

Double Guiding Catheters for Complex Percutaneous Coronary Intervention

PubMed Central

Chou, Shing-Hsien; Lin, Chia-Pin; Lin, Yen-Chen; Kuo, Chi-Tai; Lin, Ming-Shyan; Chang, Chi-Jen

2012-01-01

A large-lumen guiding catheter is often used for complex percutaneous coronary intervention—particularly when a final kissing-balloon or 2-stent technique is required. However, catheter insertion is sometimes restricted by diseased vascular access sites or a tortuous vascular route. We report 2 cases in which a unique double guiding catheter technique was used to create a lumen of sufficient size for complex percutaneous coronary intervention. In each patient, two 6F guiding catheters were used concurrently to engage the ostium of 1 target vessel. In 1 patient, these catheters were used for the delivery of 2 balloons to complete kissing-balloon dilation after single-stent placement. In the other patient, the catheters were used to deliver 2 stents sequentially to their respective target lesions. The stents were then deployed simultaneously as kissing stents, followed by high-pressure kissing-balloon postdilation. PMID:22412243

Iliac artery angioplasty : technique and results.

PubMed

Brountzos, E N; Kelekis, D A

2004-10-01

Percutaneous angioplasty is widely used for the treatment of iliac artery occlusive disease. Access to the ipsi-lateral, or less commonly contralateral, common femoral artery is obtained under local anaesthesia; the lesion is crossed with a guidewire and dilated with an angioplasty balloon catheter. This technique yields excellent immediate results with very few complications. Stent placement is used in lesions not amenable to balloon angioplasty, in complications, and recurrences. Evidence suggests that balloon angioplasty is the procedure of choice for iliac artery occlusive lesions. Stent placement should be reserved for angioplasty failures. However, primary stent placement is indicated in total occlusions. Lesion morphology is an important determinant of immediate success and long-term patency. TASC lesions type A and B are best treated with angioplasty and stenting, while TASC lesions type C and D show better results with surgical treatment. The development of new stent designs may expand the indications of the percutaneous treatment.

[How to prevent tissue overgrowth and incrustation of metal stents in the urinary tract in patients with pelvic malignancy] b ].

PubMed

Marković, Z; Masulović, D; Markovic, B; Anojcić, P; Mladenović, A

2009-01-01

At the current level of stent application in urology each irreversible urostasis contraindicated for surgical therapy implies consideration of indications for metal stent insertion. Stent incrustation which leads directly into a new uroobstruction is a characteristic complication of this method. Available experience in different uroobstructive conditions has shown that very different clinical aspects of stent usage may directly determine the possibility of their incrustation. Stent incrustation may occur in the early postprocedural course or several months later. After that, prevention of stent incrustation starts with postprocedural evaluation, selection of the stent type, and it is subsequently continued by insertion technique and lasts practically permanently after the insertion (infection control, promotion of diuresis and maintenance of normal urodynamics). Authors present own experianse in clinical aplication of metal stents in uroradiology strictures for period of last 15 years.

The predictive value of haemodynamic parameters for outcome of deep venous reconstructions in patients with chronic deep vein obstruction - A systematic review.

PubMed

Kurstjens, Rlm; de Wolf, Maf; Kleijnen, J; de Graaf, R; Wittens, Cha

2017-09-01

Objective The aim of this study was to investigate the predictive value of haemodynamic parameters on success of stenting or bypass surgery in patients with non-thrombotic or post-thrombotic deep venous obstruction. Methods EMBASE, MEDLINE and trial registries were searched up to 5 February 2016. Studies needed to investigate stenting or bypass surgery in patients with post-thrombotic obstruction or stenting for non-thrombotic iliac vein compression. Haemodynamic data needed to be available with prognostic analysis for success of treatment. Two authors, independently, selected studies and extracted data with risk bias assessment using the Quality in Prognosis Studies tool. Results Two studies using stenting and two using bypass surgery were included. Three investigated plethysmography, though results varied and confounding was not properly taken into account. Dorsal foot vein pressure and venous refill times appeared to be of influence in one study, though confounding by deep vein incompetence was likely. Another investigated femoral-central pressure gradients without finding statistical significance, though sample size was small without details on statistical methodology. Reduced femoral inflow was found to be a predictor for stent stenosis or occlusion in one study, though patients also received additional surgery to improve stent inflow. Data on prediction of haemodynamic parameters for stenting of non-thrombotic iliac vein compression were not available. Conclusions Data on the predictive value of haemodynamic parameters for success of treatment in deep venous obstructive disease are scant and of poor quality. Plethysmography does not seem to be of value in predicting outcome of stenting or bypass surgery in post-thrombotic disease. The relevance of pressure-related parameters is unclear. Reduced flow into the common femoral vein seems to be predictive for in-stent stenosis or occlusion. Further research into the predictive effect of haemodynamic parameters is warranted and the possibility of developing new techniques that evaluate various haemodynamic aspects should be explored.

Transtracheal single-point stent fixation in posttracheotomy tracheomalacia under cone-beam computer tomography guidance by transmural suturing with the Berci needle - a perspective on a new tool to avoid stent migration of Dumon stents.

PubMed

Hohenforst-Schmidt, Wolfgang; Linsmeier, Bernd; Zarogoulidis, Paul; Freitag, Lutz; Darwiche, Kaid; Browning, Robert; Turner, J Francis; Huang, Haidong; Li, Qiang; Vogl, Thomas; Zarogoulidis, Konstantinos; Brachmann, Johannes; Rittger, Harald

2015-01-01

Tracheomalacia or tracheobronchomalacia (TM or TBM) is a common problem especially for elderly patients often unfit for surgical techniques. Several surgical or minimally invasive techniques have already been described. Stenting is one option but in general long-time stenting is accompanied by a high complication rate. Stent removal is more difficult in case of self-expandable nitinol stents or metallic stents in general in comparison to silicone stents. The main disadvantage of silicone stents in comparison to uncovered metallic stents is migration and plugging. We compared the operation time and in particular the duration of a sufficient Dumon stent fixation with different techniques in a patient with severe posttracheotomy TM and strongly reduced mobility of the vocal cords due to Parkinson's disease. The combined approach with simultaneous Dumon stenting and endoluminal transtracheal externalized suture under cone-beam computer tomography guidance with the Berci needle was by far the fastest approach compared to a (not performed) surgical intervention, or even purely endoluminal suturing through the rigid bronchoscope. The duration of the endoluminal transtracheal externalized suture was between 5 minutes and 9 minutes with the Berci needle; the pure endoluminal approach needed 51 minutes. The alternative of tracheobronchoplasty was refused by the patient. In general, 180 minutes for this surgical approach is calculated. The costs of the different approaches are supposed to vary widely due to the fact that in Germany 1 minute in an operation room costs on average approximately 50-60€ inclusive of taxes. In our own hospital (tertiary level), it is nearly 30€ per minute in an operation room for a surgical approach. Calculating an additional 15 minutes for patient preparation and transfer to wake-up room, therefore a total duration inside the investigation room of 30 minutes, the cost per flexible bronchoscopy is per minute on average less than 6€. Although the Dumon stenting requires a set-up with more expensive anesthesiology accompaniment, which takes longer than a flexible investigation estimated at 1 hour in an operation room, still without calculation of the costs of the materials and specialized staff that the surgical approach would consume at least 3,000€ more than a minimally invasive approach performed with the Berci needle. This difference is due to the longer time of the surgical intervention which is calculated at approximately 180 minutes in comparison to the achieved non-surgical approach of 60 minutes in the operation suite.

Stent-Assisted Endovascular Treatment of Anterior Communicating Artery Aneurysms - Literature Review.

PubMed

Kocur, Damian; Ślusarczyk, Wojciech; Przybyłko, Nikodem; Bażowski, Piotr; Właszczuk, Adam; Kwiek, Stanisław

2016-01-01

The anterior cerebral artery is a common location of intracranial aneurysms. The standard coil embolization technique is limited by its inability to occlude wide-neck aneurysms. Stent deployment across the aneurysm neck supports the coil mass inside the aneurysmal sac, and furthermore, has an effect on local hemodynamic and biologic changes. In this article, various management strategies and techniques as well as angiographic outcomes and complications related to stent-assisted endovascular treatment of anterior communicating artery aneurysms are presented. This treatment method is safe and associated with low morbidity and mortality rates.

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.

Nitric Oxide Releasing Coronary Stent: A New Approach Using Layer-by-Layer Coating and Liposomal Encapsulation.

PubMed

Elnaggar, Mahmoud A; Seo, Seong Ho; Gobaa, Samy; Lim, Kyung Seob; Bae, In-Ho; Jeong, Myung Ho; Han, Dong Keun; Joung, Yoon Ki

2016-11-01

The sustained or controlled release of nitric oxide (NO) can be the most promising approach for the suppression or prevention of restenosis and thrombosis caused by stent implantation. The aim of this study is to investigate the feasibility in the potential use of layer-by-layer (LBL) coating with a NO donor-containing liposomes to control the release rate of NO from a metallic stent. Microscopic observation and surface characterizations of LBL-modified stents demonstrate successful LBL coating with liposomes on a stent. Release profiles of NO show that the release rate is sustained up to 5 d. In vitro cell study demonstrates that NO release significantly enhances endothelial cell proliferation, whereas it markedly inhibits smooth muscle cell proliferation. Finally, in vivo study conducted with a porcine coronary injury model proves the therapeutic efficacy of the NO-releasing stents coated by liposomal LBL technique, supported by improved results in luminal healing, inflammation, and neointimal thickening except thrombo-resistant effect. As a result, all these results demonstrate that highly optimized release rate and therapeutic dose of NO can be achieved by LBL coating and liposomal encapsulation, followed by significantly efficacious outcome in vivo. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fluoroscopic removal of retrievable self-expandable metal stents in patients with malignant oesophageal strictures: Experience with a non-endoscopic removal system.

PubMed

Kim, Pyeong Hwa; Song, Ho-Young; Park, Jung-Hoon; Zhou, Wei-Zhong; Na, Han Kyu; Cho, Young Chul; Jun, Eun Jung; Kim, Jun Ki; Kim, Guk Bae

2017-03-01

To evaluate clinical outcomes of fluoroscopic removal of retrievable self-expandable metal stents (SEMSs) for malignant oesophageal strictures, to compare clinical outcomes of three different removal techniques, and to identify predictive factors of successful removal by the standard technique (primary technical success). A total of 137 stents were removed from 128 patients with malignant oesophageal strictures. Primary overall technical success and removal-related complications were evaluated. Logistic regression models were constructed to identify predictive factors of primary technical success. Primary technical success rate was 78.8 % (108/137). Complications occurred in six (4.4 %) cases. Stent location in the upper oesophagus (P=0.004), stricture length over 8 cm (P=0.030), and proximal granulation tissue (P<0.001) were negative predictive factors of primary technical success. If granulation tissue was present at the proximal end, eversion technique was more frequently required (P=0.002). Fluoroscopic removal of retrievable SEMSs for malignant oesophageal strictures using three different removal techniques appeared to be safe and easy. The standard technique is safe and effective in the majority of patients. The presence of proximal granulation tissue, stent location in the upper oesophagus, and stricture length over 8 cm were negative predictive factors for primary technical success by standard extraction and may require a modified removal technique. • Fluoroscopic retrievable SEMS removal is safe and effective. • Standard removal technique by traction is effective in the majority of patients. • Three negative predictive factors of primary technical success were identified. • Caution should be exercised during the removal in those situations. • Eversion technique is effective in cases of proximal granulation tissue.

Is peri-operative urethral catheter drainage enough? The case for stentless pediatric robotic pyeloplasty.

PubMed

Silva, Mark V; Levy, Alison C; Finkelstein, Julia B; Van Batavia, Jason P; Casale, Pasquale

2015-08-01

The necessity for urinary diversion with trans-anastomotic ureteral stenting during pyeloplasty is currently under debate. Performing a stentless repair could eliminate stent-related morbidity, including: stent migration, urinary tract infection, flank pain, and bladder spasms. In addition, there would be no need for a second procedure and associated anesthesia required for stent removal. This study describes the outcomes of robotic-assisted laparoscopic pyeloplasty without use of a ureteral stent. An IRB-approved prospective database of all pediatric patients undergoing robotic pyeloplasty from July 2012 to July 2014 at a single institution was reviewed. The 'bypass pyeloplasty' or Anderson-Hynes dismembered pyeloplasty (DP) technique was performed. In both groups, neither a ureteral stent nor an abdominal drainage catheter was utilized. Complications were recorded, including: postoperative pain, bladder spasms, fever, and urinary tract infections. Follow-up renal ultrasound was reviewed for hydronephrosis. Twenty-seven children (17 male, 10 female) with a mean age of 25 months (range 6-157 months) underwent robotic ureteral stentless pyeloplasty during the study time period. The bypass pyeloplasty technique was performed on 19 children (70%). Mean length of stay was 20.2 hours (range 11-46). No fever, urinary tract infections, or hematuria requiring intervention were experienced. Additionally, there were no reports of bladder spasms or pain requiring pharmacotherapy. The mean follow-up was 8 months (range 4-21). Pre-operative Society of Fetal Urology grading was 3.5 and 3.4 for the dismembered and bypass cohort, respectively, with improvements to 1.1 for both groups at 3 months. Postoperative renal ultrasound hydronephrosis resolved in eight children (29.6%), improved in 14 (51.9%), and was stable in five (18.5%). The overall success rate was 100%. This study was limited by its small cohort and short follow-up, which may not thoroughly describe the efficacy of the stentless repair as it has been shown that stricture and re-obstruction can occur several years after surgery. Robotic stentless pyeloplasty is a feasible alternative to conventional methods, with excellent success rates and minimal complications. Importantly, this technique circumvents the need for a second procedure and the associated risks of anesthesia. Copyright © 2015. Published by Elsevier Ltd.

Role of Animal Models in Coronary Stenting.

PubMed

Iqbal, Javaid; Chamberlain, Janet; Francis, Sheila E; Gunn, Julian

2016-02-01

Coronary angioplasty initially employed balloon dilatation only. This technique revolutionized the treatment of coronary artery disease, although outcomes were compromised by acute vessel closure, late constrictive remodeling, and restenosis due to neointimal proliferation. These processes were studied in animal models, which contributed to understanding the biology of endovascular arterial injury. Coronary stents overcome acute recoil, with improvements in the design and metallurgy since then, leading to the development of drug-eluting stents and bioresorbable scaffolds. These devices now undergo computer modeling and benchtop and animal testing before evaluation in clinical trials. Animal models, including rabbit, sheep, dog and pig are available, all with individual benefits and limitations. In smaller mammals, such as mouse and rabbit, the target for stenting is generally the aorta; whereas in larger animals, such as the pig, it is generally the coronary artery. The pig coronary stenting model is a gold-standard for evaluating safety; but insights into biomechanical properties, the biology of stenting, and efficacy in controlling neointimal proliferation can also be gained. Intra-coronary imaging modalities such as intravascular ultrasound and optical coherence tomography allow precise serial evaluation in vivo, and recent developments in genetically modified animal models of atherosclerosis provide realistic test beds for future stents and scaffolds.

Provisional vs. two-stent technique for unprotected left main coronary artery disease after ten years follow up: A propensity matched analysis.

PubMed

D'Ascenzo, Fabrizio; Iannaccone, Mario; Giordana, Francesca; Chieffo, Alaide; Connor, Stephen O; Napp, L Christian; Chandran, SujaySubash; de la Torre Hernández, José María; Chen, Shao-Liang; Varbella, Ferdinando; Omedè, Pierluigi; Taha, Salma; Meliga, Emanuele; Kawamoto, Hiroyoshi; Montefusco, Antonio; Chong, Mervyn; Garot, Philippe; Sin, Lin; Gasparetto, Valeria; Abdirashid, Mohamed; Cerrato, Enrico; Biondi-Zoccai, Giuseppe; Gaita, Fiorenzo; Escaned, Javier; Hiddick Smith, David; Lefèvre, Thierry; Colombo, Antonio; Sheiban, Imad; Moretti, Claudio

2016-05-15

There is uncertainty on which stenting approach confers the best long-term outlook for unprotected left main (ULM) bifurcation disease. This is a non-randomized, retrospective study including all consecutive patients with 50% stenosis of the left main involving at least 1 of the arteries stemming from the left main treated with drug-eluting stents (DES) in 9 European centers between 2002 and 2004. Patients were divided into two groups: those treated with provisional stentings vs. those treated with two stent strategy. The outcomes of interest were 10-year rates of target lesion revascularization (TLR), major adverse cardiac events (MACE), and their components (cardiovascular death, myocardial infarction [MI], or repeat revascularization), along with stent thrombosis (ST). A total of 285 patients were included, 178 (62.5%) in the provisional stenting group and 87 (37.5%) in the two stent group. After 10 years, no differences in TLR were found at unadjusted analysis (19% vs 25%, p>0.05) nor after propensity score matching (25% vs 28%, p>0.05). Similar rates of MACE (60% vs 66%, p>0.05), death (34% vs 43%, p>0.05), MI (9% vs 14%, p>0.05) and ST were also disclosed at propensity-based analysis. Even after 10 year follow-up, patients treated with provisional stenting on left main showed comparable rates of target lesion revascularization compared to two stent strategy. Copyright © 2016 Elsevier Ireland 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.

Air cholangiography in endoscopic bilateral stent-in-stent placement of metallic stents for malignant hilar biliary obstruction.

PubMed

Lee, Jae Min; Lee, Sang Hyub; Jang, Dong Kee; Chung, Kwang Hyun; Park, Jin Myung; Paik, Woo Hyun; Lee, Jun Kyu; Ryu, Ji Kon; Kim, Yong-Tae

2016-03-01

Although endoscopic bilateral stent-in-stent (SIS) placement of self-expandable metallic stents (SEMS) is one of the major palliative treatments for unresectable malignant hilar biliary obstruction, post-endoscopic retrograde cholangiopancreatography (ERCP) cholangitis can occur frequently due to inadequate drainage, especially after contrast injection into the biliary tree. The aim of this study is to evaluate the efficacy and safety of air cholangiography-assisted stenting. This study included 47 patients with malignant hilar biliary obstruction who underwent endoscopic bilateral SEMS placement using the SIS technique. They were divided into two groups, air (n = 23) or iodine contrast (n = 24) cholangiography. We retrospectively compared comprehensive clinical and laboratory data of both groups. There were no significant differences found between the two groups with respect to technical success (87% versus 87.5%, air versus contrast group, respectively), functional success (95% versus 95.2%), 30-day mortality (8.3% versus 8.7%) and stent patency. Post-ERCP adverse events occurred in 5 (21.7%) of the patients in the air group and 8 (33.3%) of the patients in the contrast group. Among these, the rate of cholangitis was significantly lower in the air group (4.8% versus 29.2%, p = 0.048). In multivariate analysis, air cholangiography, technical success and a shorter procedure time were significantly associated with a lower incidence of post-ERCP cholangitis. Air cholangiography-assisted stenting can be a safe and effective method for endoscopic bilateral SIS placement of SEMS in patients with malignant hilar biliary obstruction.

A combined technique using a muscular flap and endobronchial stent to repair complex broncho-oesophageal fistulae supported by ECMO.

PubMed

Baste, Jean-Marc; Haddad, Laura; Philouze, Guillaume

2018-02-01

Certain broncho-oesophageal fistulae require surgical repair. Herein, we describe an innovative surgical technique combining intercostal flap and endobronchial stenting. Two patients, each with a with complex broncho-oesophageal fistula 2 years after radio-chemotherapy, were hospitalised for severe respiratory infection and extension of the fistula despite previous endoscopic treatment. The first patient presented with respiratory distress (ARDS). She had emergency surgery under extra corporeal membrane oxygenation: oesophagectomy and reconstruction of the left bronchus by a vascularised intercostal flap. Stenting was performed on day 10, due to persistence of the fistula. At 3 months the bronchus was healed, but the patient died of cerebral bleeding. For the second patient, repair was proposed before severe ARDS with the same surgical and ventilatory strategy and a stent was preventively inserted after surgery. After 3 months, the stent was removed and the left bronchus was healed. Complex post-radiotherapy broncho-oesophageal fistulae should be treated surgically before respiratory complications arise, by combining reconstruction with a vascularised flap and transient stenting.

Percutaneous Transluminal Cerebral Angioplasty and Stenting in Acute Vertebrobasilar Ischemic Stroke

PubMed Central

Nistri, M.; Mangiafico, S.; Cellerini, M.; Villa, G.; Mennonna, P.; Ammannati, F.; Giordano, G. P.

2002-01-01

Summary Reports of cerebral transluminal angioplasty and stenting in patients with vertebrobasilar ischemic stroke are scanty. Herein we report on the use of “monorail” coronary balloon angioplasty and stent balloon mounted catheters in two patients with acute vertebrobasilar ischemic stroke, focussing on the differences and possible advantages of the “monorail” technique in comparison with the “over-the-wire” technique. In both patients, the clinical picture was characterized by progressive brainstem symptoms followed by acute loss of consciousness related to an atherothrombotic occlusion and subocclusion of the dominant intracranial vertebral artery, respectively. In one patient, superselective thrombolytic therapy and balloon angioplasty resulted in a dissection flap at the vertebrobasilar junction. The latter was treated by successful deployment of a coronary stent. In the other patient, the subocclusive lesion was directly treated by angioplasty and stenting without thrombolytic therapy. The clinical outcome was poor for one patient (“locked in” syndrome) while the other had a complete clinical recovery. In acute atherothrombotic vertebrobasilar stroke transluminal cerebral angioplasty and stenting may be successfully performed allowing vessel recanalization. PMID:20594522

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.

Functional Nanoarchitectures For Enhanced Drug Eluting Stents

NASA Astrophysics Data System (ADS)

Saleh, Yomna E.; Gepreel, Mohamed A.; Allam, Nageh K.

2017-01-01

Different strategies have been investigated to allow for optimum duration and conditions for endothelium healing through the enhancement of coronary stents. In this study, a nanoarchitectured system is proposed as a surface modification for drug eluting stents. Highly oriented nanotubes were vertically grown on the surface of a new Ni-free biocompatible Ti-based alloy, as a potential material for self-expandable stents. The fabricated nanotubes were self-grown from the potential stent substrate, which are also proposed to enhance endothelial proliferation while acting as drug reservoir to hinder Vascular Smooth Muscle Cells (VSMC) proliferation. Two morphologies were synthesized to investigate the effect of structure homogeneity on the intended application. The material was characterized by field-emission scanning electron microscope (FESEM), X-ray diffraction (XRD), Raman spectroscopy, energy dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS). Nanoindentation technique was used to study the mechanical properties of the fabricated material. Cytotoxicity and proliferation studies were performed and compared for the two fabricated nanoarchitectures, versus smooth untextured samples, using in-vitro cultured endothelial cells. Finally, the drug loading capacity was experimentally studied and further supported by computational modeling of the release profile.

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.

Alteration of intraaneurysmal hemodynamics by placement of a self-expandable stent. Laboratory investigation.

PubMed

Tateshima, Satoshi; Tanishita, Kazuo; Hakata, Yasuhiro; Tanoue, Shin-ya; Viñuela, Fernando

2009-07-01

Development of a flexible self-expanding stent system and stent-assisted coiling technique facilitates endovascular treatment of wide-necked brain aneurysms. The hemodynamic effect of self-expandable stent placement across the neck of a brain aneurysm has not been well documented in patient-specific aneurysm models. Three patient-specific silicone aneurysm models based on clinical images were used in this study. Model 1 was constructed from a wide-necked internal carotid artery-ophthalmic artery aneurysm, and Models 2 and 3 were constructed from small wide-necked middle cerebral artery aneurysms. Neuroform stents were placed in the in vitro aneurysm models, and flow structures were compared before and after the stent placements. Flow velocity fields were acquired with particle imaging velocimetry. In Model 1, a clockwise, single-vortex flow pattern was observed in the aneurysm dome before stenting was performed. There were multiple vortices, and a very small fast flow stream was newly formed in the aneurysm dome after stenting. The mean intraaneurysmal flow velocity was reduced by approximately 23-40%. In Model 2, there was a clockwise vortex flow in the aneurysm dome and another small counterclockwise vortex in the tip of the aneurysm dome before stenting. The small vortex area disappeared after stenting, and the mean flow velocity in the aneurysm dome was reduced by 43-64%. In Model 3, a large, counterclockwise, single vortex was seen in the aneurysm dome before stenting. Multiple small vortices appeared in the aneurysm dome after stenting, and the mean flow velocity became slower by 22-51%. The flexible self-expandable stents significantly altered flow velocity and also flow structure in these aneurysms. Overall flow alterations by the stent appeared favorable for the long-term durability of aneurysm embolization. The possibility that the placement of a low-profile self-expandable stent might induce unfavorable flow patterns such as a fast flow stream in the aneurysm dome cannot be excluded.

[The bioresorbable coronary stent: a revolution].

PubMed

Koegler, Flora; De Benedetti, Edoardo

2013-04-10

Coronary angioplasty has undergone several technological revolutions: starting with balloon angioplasty, then with bare metal stent and finally with drug eluting stent (DES), this technique is now mature. However, once we thought the problem of instent restenosis solved with DES, new concerns arise with late and very late stent thrombosis. Should we therefore proscribe DES? How long should be the duration of dual antiplatelet therapy? And how should we manage the patients who need a surgery and are at high risk of bleeding? Are bioresorbable stents the final solution with their initial mechanical properties, then with their drug eluting effect against intra-stent restenosis, and finally with their complete resorption which leaves the artery free of any foreign material?

Management of large bowel obstruction with self-expanding metal stents. A multicentre retrospective study of factors determining outcome.

PubMed

Geraghty, J; Sarkar, S; Cox, T; Lal, S; Willert, R; Ramesh, J; Bodger, K; Carlson, G L

2014-06-01

UK cancer guidelines recommend patients with colonic obstruction due to suspected malignancy be considered for stenting with a self-expanding metal stent (SEMS). Considerable variation in practice exists due to a lack of expertise, technical difficulties and other, as yet ill-defined features. This retrospective multi-centre study aims to determine the outcome following colonic stenting for large bowel obstruction and identify factors associated with successful intervention. A regional programme of colonic stenting for large bowel obstruction, in five UK centres from 2005 to 2010 was evaluated for outcome including technical and clinical success, survival, complications and reoperation. A SEMS was inserted in 334 patients, including 264 (79.0%) for palliation and 52 (15.6%) as a bridge to surgery. Technical success was achieved in 292 (87.4%) patients, with 46 (13.8%) experiencing a complication or technical failure. Reoperation was required in 39 (14.8%) patients stented for palliation of colorectal cancer of whom 16 (6.1%) subsequently required a colostomy. A one-stage primary anastomosis was achieved in 35 (67.3%) of the 52 patients undergoing stenting as a bridge to resection. Technical success did not vary by indication or site of obstruction (P = 0.60) but was higher for operators who had performed more than 10 procedures (OR 3.34, P = 0.001). ASA grade ≥3 predicted a worse clinical outcome (OR 0.43, P = 0.04). The through-the-scope (TTS) endoscopy technique was more successful than radiological placement alone (90.3% vs 74.8%, P < 0.001). Experienced operators using a TTS technique achieved a better outcome for the emergency management of large bowel obstruction. Older, sicker patients and those with extracolonic and benign strictures fared less well. Colorectal Disease © 2014 The Association of Coloproctology of Great Britain and Ireland.

Wireless magnetoelastic transducers for biomedical applications

NASA Astrophysics Data System (ADS)

Green, S. R.; Gianchandani, Y. B.

2017-05-01

This paper highlights emerging medical applications for magnetoelastic sensing and actuation, each taking advantage of the wireless capabilities and small form factor enabled by the magnetoelastic transduction technique. Magnetoelastic transduction leverages the strong coupling between stress, strain, and magnetization intrinsic to some materials - notably amorphous metals and rare earth crystalline alloys. This coupling provides inherently wireless transduction that does not require any onboard power; these traits are especially advantageous in diagnostic and therapeutic medical implant applications. This paper first describes the basic transduction technique, and considerations for design and fabrication of medical systems which utilize the technique. These considerations include material selection, magnetic biasing, packaging, and interrogation approaches. The first application highlighted is stent monitoring, in which the masssensitive magnetoelastic resonator is integrated along the inner sidewall of the stent to provide early detection of stent occlusion. Prototype tests indicate clinical feasibility and a full scale range from zero stent occlusion to full stent occlusion. Wireless ranges of up to 15 cm in situ have been achieved using 25 mm long resonators. The second application is wireless strain sensing, which can be useful for orthopedic implants and orthodontia. A differential strain sensor is described, with a dynamic range of 0-1.85 mstrain - accommodating typical palatal expander strain - and a sensitivity of 12.5x103 ppm/mstrain. Finally, a wireless actuator intended to agitate fluid for mitigation of encapsulation of glaucoma drainage devices is shown. Peak actuator vibration amplitudes of 1.5 μm - sufficient to affect cell adhesion in other studies - are recorded at a wireless range of 25-30 mm.

Stent longitudinal integrity bench insights into a clinical problem.

PubMed

Ormiston, John A; Webber, Bruce; Webster, Mark W I

2011-12-01

Standardized bench-top compression and elongation testing was undertaken to assess the longitudinal strength of contemporary stents. Insights gained may improve clinical stent choice and deployment techniques, and facilitate future stent design improvements. The hoops of coronary stents provide radial support, and connectors hold hoops together. Strut material, shape, and thickness, along with connector number and configuration, provide the balance between stent flexibility and longitudinal integrity. Longitudinal distortion manifests as length change, strut overlap, strut separation, malapposition, and luminal obstruction. These may predispose to restenosis and stent thrombosis, obstruct passage of devices, be misinterpreted as strut fracture, and require additional stenting. The force required to compress and to elongate 7 contemporary stents was measured with an Instron universal testing machine (Norwood, Massachusetts). Stents deployed in a silicone phantom damaged by a balloon or guide catheter were imaged by microcomputed tomography to understand better the appearances and effects of longitudinal distortion. Stents with 2 connectors (Boston Scientific [Natick, Massachusetts] Omega and Medtronic [Santa Rosa, California] Driver) required significantly less force to be compressed up to 5 mm and elongated by 1 mm than designs with more connectors. The 6-connector Cypher Select required significantly more force to be elongated 5 mm than other designs. Stents with 2 connectors between hoops have less longitudinal strength when exposed to compressing or elongating forces than those with more connectors. This independent, standardized study may assist stent selection in clinical situations where longitudinal integrity is important, and may aid future design improvements. Stent longitudinal strength, the resistance to shortening or elongation, appears related to the number of connectors between hoops. Using a standardized testing protocol, designs with 2 connectors were more likely to shorten or elongate than those with more connectors. Distortion may be recognized clinically as bunching or separation of struts, and may be confused with strut fracture. Without post-dilation or further stent deployment, the patient may be at increased risk for adverse clinical events. A stent design change ensuring 3 connectors, especially at the proximal end of a stent, should increase longitudinal integrity, but perhaps at the expense of stent flexibility. Copyright © 2011 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

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.

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

OCT assisted identification of the grade of encrustation of urologic catheters

NASA Astrophysics Data System (ADS)

Sroka, Ronald; Püls, Michaela; Stepp, Herbert; Zilinberg, Katja; Bader, Markus; Weidlich, Patrick

2013-06-01

Introduction: Ureteric stenting is a commonly used endourologic procedure for temporary and long-term drainage of an obstructed upper urinary tract. The indication for ureteric stenting is obstruction due to intrinsic (intraureteral stones, strictures, or tumors) or extrinsic (for example compressing pelvic or retroperitoneal mass) causes. Despite the fact that stents do certainly have proven benefits in all fields of urology, there are potential morbidities. The most common problem of indwelling ureteral stents is infection. As foreign body in the urinary system, stents act as a nidus for bacteria colonization, crystallization and encrustation. Bacteria induced biofilm formation predisposes for the crystallization of lithogenic salts, such as calcium-phosphate, calcium-oxalate, magnesium-phosphate on the surface initiating stent encrustation. It was the objective of this study to evaluate whether optical coherence tomography (OCT) using both the surface and the endoluminal technique is feasible to investigate the locations and degree of encrustation process in clinically used ureteral stents. Patients and methods: After removal from patients, fourteen polyurethane JJ stents were investigated. A fresh JJ served as a control. The external surfaces were examined using an endoscopic surface OCT whereas the intraluminal surfaces were investigated by an endoluminal radial OCT device. The focus was on detection of encrustation or crystalline sedimentation. Results: In 12 female and 2 male patients, the median indwelling time of the ureteral catheter was 100 days (range 19- 217). Using the endoluminal OCT, the size and grade of intraluminal encrustation could be expressed as a percentage relating to the open lumen of the reference stent. The maximum encrustation observed resulted in a remaining unrestricted lumen of 15-35% compared to the reference. The luminal reduction caused by encrustation was significantly higher at the proximal end of the ureteral stent as compared to its distal part. The extraluminal OCT-investigations facilitated the characterization of extraluminal encrustation. Conclusion: OCT techniques were feasible and facilitated the detection of encrustation of double pigtail catheters on both the extra and intra luminal surface. Quantitative expression of the degree of intraluminal encrustation could be achieved, with the most dense and thickened occurrence of intraluminal incrustation in the upper curl of the JJ stent.

Risk Factors for Migration, Fracture, and Dislocation of Pancreatic Stents

PubMed Central

Kawaguchi, Yoshiaki; Lin, Jung-Chun; Kawashima, Yohei; Maruno, Atsuko; Ito, Hiroyuki; Ogawa, Masami; Mine, Tetsuya

2015-01-01

Aim. To analyze the risk factors for pancreatic stent migration, dislocation, and fracture in chronic pancreatitis patients with pancreatic strictures. Materials and Methods. Endoscopic stent placements (total 386 times) were performed in 99 chronic pancreatitis patients with pancreatic duct stenosis at our institution between April 2006 and June 2014. We retrospectively examined the frequency of stent migration, dislocation, and fracture and analyzed the patient factors and stent factors. We also investigated the retrieval methods for migrated and fractured stents and their success rates. Results. The frequencies of stent migration, dislocation, and fracture were 1.5% (5/396), 0.8% (3/396), and 1.2% (4/396), respectively. No significant differences in the rates of migration, dislocation, or fracture were noted on the patient factors (etiology, cases undergoing endoscopic pancreatic sphincterotomy, location of pancreatic duct stenosis, existence of pancreatic stone, and approach from the main or minor papilla) and stent factors (duration of stent placement, numbers of stent placements, stent shape, diameter, and length). Stent retrieval was successful in all cases of migration. In cases of fractured stents, retrieval was successful in 2 of 4 cases. Conclusion. Stent migration, fracture, and dislocation are relatively rare, but possible complications. A good understanding of retrieval techniques is necessary. PMID:25945085

A Novel 'Cheese Wire' Technique for Stent Positioning Following Difficult Iliac Artery Subintimal Dissection and Aortic Re-Entry

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

Watkinson, A. F., E-mail: anthony.watkinson@rdeft.nhs.u

2009-07-15

Subintimal wire dissection is a well-established method for traversing difficult vascular occlusions. This technique relies on re-entry of the true lumen distal to the occlusion, which may be difficult in diseased vessels with significant calcification. This case report describes a novel 'cheese wire' technique to allow stent positioning without the use of proprietary re-entry devices.

Rigid bronchoscopy and silicone stents in the management of central airway obstruction

PubMed Central

Yarmus, Lonny

2015-01-01

The field of interventional pulmonology has grown significantly over the past several decades now including the diagnosis and therapeutic treatment of complex airway disease. Rigid bronchoscopy is an invaluable tool in the diagnosis and management of several malignant and non-malignant causes of central airway obstruction (CAO) and has become integral after the inception of airway stenting. The management of CAO can be a complicated endeavor with significant risks making the understanding of basic rigid bronchoscopy techniques, ablative technologies, anesthetic care and stenting of utmost importance in the care of these complex patients. This review article will focus on the history of rigid bronchoscopy, the technical aspects of performing a rigid bronchoscopy as well as the use of silicone stents their indications, complications and placement techniques. PMID:26807283

Endovascular Stent-Graft Placement in Patients with Stanford Type B Aortic Dissection in China: A Systematic Review.

PubMed

Wang, Junwei; Li, Yonghui; Li, Yongxin; Ren, Zefang; Chen, Peng; Qian, Xueke; Wang, Shenming; Wang, Jinsong

2016-10-01

Improvements in stent-graft devices and increasing clinical experience with the technique have improved outcomes and expanded clinical indications in patients with Stanford type B aortic dissection (AD) in China. However, the evolution of and modifications to stent grafts have not been reviewed. The aim of this study was to summarize all available published data on technical success, potential benefits, complications, stent evolution, and survival rates associated with endovascular stent-graft placements in patients with Stanford type B AD in China. We performed comprehensive searches of the Chinese-language medical literature in Chinese Biomedical Database, China National Knowledge Infrastructure, and Wanfang Data and of the English-language medical literature in PubMed, Web of Science, and the Cochrane Library. This systematic review was based on all retrospective studies assessing outcomes of Stanford type B AD treated with endovascular stent-graft placement in China. A total of 153 retrospective studies that included 8,694 cases were analyzed in this study. Procedure success was reported in 99.7 ± 0.1% of patients. Overall complications were reported in 19.1 ± 0.6% of patients. Postoperative endoleaks occurred in 7.2 ± 0.3% of patients. Major complications were reported in 3.2 ± 0.2% of patients, with a neurological complication rate of 1.3 ± 0.1%. Periprocedural stroke occurred more frequently than did paraplegia (0.8 ± 0.1% vs. 0.1 ± 0.04%). Overall complications were significantly greater in patients treated with first-generation stents than in those treated with second-generation stents (25.1 ± 1.2% vs. 9.5 ± 0.9%, P < 0.001). The in-hospital mortality rate was 1.6 ± 0.1%. In addition, 1.8 ± 0.2% of patients died during a mean follow-up period of 29.4 ± 13.5 months. The Kaplan-Meier estimates of the overall survival rate were 99.0 ± 0.1% at 30 days, 98.5 ± 0.2% at 6 months, 98.4 ± 0.2% at 1 year, 98.1 ± 0.2% at 2 years, and 97.9 ± 0.2% at 5 years. Endovascular stent-graft placement is feasible and has a high technique success rate as well as favorable neurological complication and survival rates when used to treat Stanford type B AD. The new generation of stent grafts appears to have favorable in-hospital and follow-up outcomes. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Stent placement with the monorail technique for treatment of mesenteric artery stenosis.

PubMed

Schaefer, Philipp J; Schaefer, Fritz K W; Hinrichsen, Holger; Jahnke, Thomas; Charalambous, Nikolas; Heller, Martin; Mueller-Huelsbeck, Stefan

2006-04-01

To analyze the immediate and midterm success of stenting of mesenteric arteries by a monorail technique in patients with chronic mesenteric ischemia. In this prospective case series, 19 patients (11 male, 8 female; mean age, 62.9 +/- 10.4 y; range, 36-82 y) with 23 symptomatic stenoses of mesenteric arteries were treated with stent placement by a monorail technique in a radiologic intervention center over a period of 4.5 years. Clinical examinations and duplex sonography were used to evaluate the stents' patency and clinical success. Kaplan-Meier graphs were calculated to analyze the patency and freedom-from-symptom rate. Initial technical success rate was 22/23 (96%). Mean follow-up was 17 months (range, 1-58 mo). Primary patency and primary clinical success rates were 82% and 78%, respectively. According to Kaplan-Meier tables, the patency rates were 96%, 87%, 76%, and 61% at 0, 1, 15, and 24 months, respectively, and the freedom-from-symptom rates were 95%, 90%, 72%, and 54% at 0, 1, 24, and 30 months, respectively. No peri-interventional complications occurred. Two patients died of cardiac failure in the hospital within 30 days after intervention; deaths were not related to the intervention. Stent placement by a monorail technique in mesenteric arteries is an effective and safe treatment for symptomatic stenoses in patients with chronic mesenteric ischemia after a mean follow-up of 17 months.

Reproducibility of haemodynamical simulations in a subject-specific stented aneurysm model--a report on the Virtual Intracranial Stenting Challenge 2007.

PubMed

Radaelli, A G; Augsburger, L; Cebral, J R; Ohta, M; Rüfenacht, D A; Balossino, R; Benndorf, G; Hose, D R; Marzo, A; Metcalfe, R; Mortier, P; Mut, F; Reymond, P; Socci, L; Verhegghe, B; Frangi, A F

2008-07-19

This paper presents the results of the Virtual Intracranial Stenting Challenge (VISC) 2007, an international initiative whose aim was to establish the reproducibility of state-of-the-art haemodynamical simulation techniques in subject-specific stented models of intracranial aneurysms (IAs). IAs are pathological dilatations of the cerebral artery walls, which are associated with high mortality and morbidity rates due to subarachnoid haemorrhage following rupture. The deployment of a stent as flow diverter has recently been indicated as a promising treatment option, which has the potential to protect the aneurysm by reducing the action of haemodynamical forces and facilitating aneurysm thrombosis. The direct assessment of changes in aneurysm haemodynamics after stent deployment is hampered by limitations in existing imaging techniques and currently requires resorting to numerical simulations. Numerical simulations also have the potential to assist in the personalized selection of an optimal stent design prior to intervention. However, from the current literature it is difficult to assess the level of technological advancement and the reproducibility of haemodynamical predictions in stented patient-specific models. The VISC 2007 initiative engaged in the development of a multicentre-controlled benchmark to analyse differences induced by diverse grid generation and computational fluid dynamics (CFD) technologies. The challenge also represented an opportunity to provide a survey of available technologies currently adopted by international teams from both academic and industrial institutions for constructing computational models of stented aneurysms. The results demonstrate the ability of current strategies in consistently quantifying the performance of three commercial intracranial stents, and contribute to reinforce the confidence in haemodynamical simulation, thus taking a step forward towards the introduction of simulation tools to support diagnostics and interventional planning.

Modified Activation Technique for Nasal Stent of Nasoalveolar Molding Appliance for Columellar Lengthening in Bilateral Cleft Lip/Palate.

PubMed

Patil, Pravinkumar G; Nimbalkar-Patil, Smita P

2018-01-01

Bilateral cleft lip/cleft palate is associated with nasal deformities typified by a short columella. The presurgical nasoalveolar molding (NAM) therapy approach includes reduction of the size of the intraoral alveolar cleft as well as positioning of the surrounding deformed soft tissues and cartilages. In a bilateral cleft patient, NAM, along with columellar elongation, eliminates the need for columellar lengthening surgery. Thus the frequent surgical intervention to achieve the desired esthetic results can be avoided. This article proposes a modified activation technique of the nasal stent for a NAM appliance for columellar lengthening in bilateral cleft lip/palate patients. The design highlights relining of the columellar portion of the nasal stent and the wire-bending of the nasal stent to achieve desirable results within the limited span of plasticity of the nasal cartilages. With this technique the vertical taping of the premaxilla to the oral plate can be avoided. © 2016 by the American College of Prosthodontists.

Advanced Technical Considerations for Implanting the t-Branch Off-the-Shelf Multibranched Stent-Graft to Treat Thoracoabdominal Aneurysms.

PubMed

Ferreira, Marcelo; Ferreira, Diego; Cunha, Rodrigo; Bicalho, Guilherme; Rodrigues, Eduardo

2018-06-01

To demonstrate different techniques and device modifications that can expand the anatomic suitability of the off-the-shelf multibranched t-Branch for treatment of thoracoabdominal aortic aneurysm. The t-Branch device is not customized for specific patient anatomy, and the most frequent limitations to its use are an inadequate sealing zone and renal artery anatomy. Experience with this device has prompted the development of several techniques that can be employed to maximize the suitability of this stent-graft. Advice is offered on modification of the device to minimize the risk of paraplegia or better match patient anatomy. Maneuvers are explained to ease delivery through tortuous anatomy or existing stent-grafts, catheterize visceral target vessels, select a bridging stent, reduce ischemia time in the limbs, and alter the configuration of the branches. Employing adjunctive maneuvers can increase the anatomic suitability of the t-Branch; in our experience, these techniques have increased the applicability to more than 80% of all elective and urgent thoracoabdominal aortic aneurysm cases.

In vitro experiments of vessel wall apposition between the Enterprise and Enterprise 2 stents for treatment of cerebral aneurysms.

PubMed

Kono, Kenichi; Terada, Tomoaki

2016-02-01

A closed-cell stent called Enterprise has been used for stent-assisted coil embolization of cerebral aneurysms. The Enterprise stent tends to cause kinks and vessel wall malposition in curved vessels and may cause thromboembolic complications. We evaluated vessel wall apposition of a new closed-cell stent, Enterprise 2, compared with a previous Enterprise stent, using curved vascular silicone models. The Enterprise or Enterprise 2 stent was deployed in curved vascular models with various radii of approximately 5 to 10 mm. Stent deployment was performed 25 times in each stent. A push-pull technique was used to minimize incomplete wall apposition. To evaluate conformity of stents, gaps between a stent and a vessel wall were measured. The gap ratio (gap / a wall diameter) was 15 % ± 17 % (mean ± standard deviation) and 41 % ± 15 % with the Enterprise 2 stent and the Enterprise stent, respectively. Taking gap ratios and radii of vessel curvature into consideration, the Enterprise 2 stent had significantly better wall apposition than the Enterprise stent (p = 0.005). In the same radius of vessel curvature, the Enterprise 2 stent had approximately half of the gap compared with the Enterprise stent. There were no significant differences in vessel straightening effects between the two stents. The Enterprise 2 stent has better wall apposition in curved vessels than the Enterprise stent. The gap between a vessel wall and the Enterprise 2 stent is approximately half that of the Enterprise stent. However, gaps and kinks are still present in curved vessels with a small radius. Caution should be taken for kinks and malposition in acutely curved vessels, such as the siphon of the internal carotid artery.

Stent-Assisted Endovascular Treatment of Anterior Communicating Artery Aneurysms – Literature Review

PubMed Central

Kocur, Damian; Ślusarczyk, Wojciech; Przybyłko, Nikodem; Bażowski, Piotr; Właszczuk, Adam; Kwiek, Stanisław

2016-01-01

Summary The anterior cerebral artery is a common location of intracranial aneurysms. The standard coil embolization technique is limited by its inability to occlude wide-neck aneurysms. Stent deployment across the aneurysm neck supports the coil mass inside the aneurysmal sac, and furthermore, has an effect on local hemodynamic and biologic changes. In this article, various management strategies and techniques as well as angiographic outcomes and complications related to stent-assisted endovascular treatment of anterior communicating artery aneurysms are presented. This treatment method is safe and associated with low morbidity and mortality rates. PMID:27559426

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.

A randomized trial comparing primary angioplasty versus stent placement for symptomatic intracranial stenosis

PubMed Central

Qureshi, Adnan I; Chaudhry, Saqib A; Siddiq, Farhan; Majidi, Shahram; Rodriguez, Gustavo J; Suri, M Fareed K

2013-01-01

Background: Both primary angioplasty alone and angioplasty with a self-expanding stent have been compared in non-randomized concurrent clinical studies that suggest equivalent results. However, there is no randomized trial that has compared the two procedures in patients with symptomatic high grade intracranial stenosis. Objective: The primary aim of the randomized trial was to compare the clinical and angiographic efficacy of primary angioplasty and angioplasty followed by stent placement in preventing restenosis, stroke, requirement for second treatment, and death in patients with symptomatic intracranial stenosis. Methods: The study prospectively evaluated efficacy and safety of the two existing neurointerventional techniques for treatment of moderate intracranial stenosis (stenosis ≥ 50%) with documented failure of medical treatment or severe stenosis (≥70%) with or without failure of medical treatment. Results: A total of 18 patients were recruited in the study (mean age [±SD] was 64.7 ± 15.1 years); out of these, 12 were men. Of these 18, 10 were treated with primary angioplasty and 8 were treated with angioplasty followed by self-expanding stent. The technical success rates of intracranial angioplasty and stent placements defined as ability to achieve <30% residual stenosis when assessed by immediate post-procedure angiography was 5 of 10 and 5 of 8 patients, respectively. The total fluoroscopic time (mean [±SD]) was lower in patients undergoing primary angioplasty 37 [±11] min versus those undergoing angioplasty followed by self-expanding stent 42 [±15] min, P = 0.4321. The stroke and death rate within 1 month was very low in both patient groups (1 of 10 versus 0 of 8 patients). One patient randomized to stent placement continued to have recurrent ischemic symptoms requiring another angioplasty in the vertebral artery on post-procedure Day 2. Conclusions: The trial suggests that a randomized trial comparing primary angioplasty to angioplasty followed by stent placement is feasible. The immediate procedural outcomes with primary angioplasty are comparable to stent placement and warrant further studies. PMID:24358415

Biodegradable Stents: An Evolution in Management of Benign Intestinal Strictures.

PubMed

Jain, Deepanshu; Mahmood, Ejaz; Singhal, Shashideep

2017-04-01

Benign intestine strictures secondary to postoperative narrowing or inflammatory bowel disease can be managed surgically or conservatively. Some patients may not be suitable surgical candidates and some patients may choose not to have repeat surgery. Biodegradable (BD) stents offer a prolonged dilatory effect before gradual degradation and obviates the need of a second procedure for stent removal. BD stents have high technical success rates (mean, 94.4%; median, 100%; range, 86% to 100%) but widely variable clinical success rates (range, 45% to 100%). Stent migration is the most commonly reported complication (mean, 22.2%; range, 0% to 36%). In the future, with better understanding of the factors contributing to stent migration, improvement in present stent design and better anchoring techniques, the stent migration rate is expected to decrease and improve clinical outcome. The role of prophylactic BD stent placement to prevent stricture development postintestine surgery is an intriguing idea and needs to be explored. As of now, the use of BD stents is a reasonable option for patients with dilatation resistant intestinal strictures who are unfit for surgery or refuse to have surgical treatment.

Endoscopic Ultrasound-guided Bilio-pancreatic Drainage

PubMed Central

Giovannini, Marc; Bories, Erwan; Téllez-Ávila, Félix I.

2012-01-01

The echoendoscopic biliary drainage is an option to treat obstructive jaundices when endoscopic retrograde cholangiopancreatography (ERCP) drainage fails. These procedures compose alternative methods to the side of surgery and percutaneous transhepatic biliary drainage, and it was only possible by the continuous development and improvement of echoendoscopes and accessories. The development of linear sectorial array echoendoscopes in early 1990 brought a new approach to diagnostic and therapeutic dimension on echoendoscopy capabilities, opening the possibility to perform punction over direct ultrasonografic view. Despite of the high success rate and low morbidity of biliary drainage obtained by ERCP, difficulty could be found at the presence of stent tumor ingrown, tumor gut compression, periampullary diverticula and anatomic variation. The echoendoscopic technique starts performing punction and contrast of the left biliary tree. When performed from gastric wall, the access is made through hepatic segment III. From duodenum, direct common bile duct punction. Diathermic dilatation of the puncturing tract is required using a 6-Fr cystostome and a plastic or metal stent is introducted. The techincal success of hepaticogastrostomy is near 98%, and complications are present in 20%: pneumoperitoneum, choleperitoneum, infection and stent disfunction. To prevent bile leakage, we have used the 2-stent techniques. The first stent introduced was a long uncovered metal stent (8 or 10 cm) and inside this first stent a second fully covered stent of 6 cm was delivered to bridge the bile duct and the stomach. Choledochoduodenostomy overall success rate is 92%, and described complications include, in frequency order, pneumoperitoneum and focal bile peritonitis, present in 14%. By the last 10 years, the technique was especially performed in reference centers, by ERCP experienced groups, and this seems to be a general guideline to safer procedure execution. The ideal approach for pancreatic pseudocyst (PPC) puncture combines endos-copy with real time endosonography using an interventional echoendoscope. Several authors have described the use of endoscopic ultrasound (EUS) longitudinal scanners for guidance of transmural puncture and drainage procedures. The same technique could be used to access a dilated pancreatic duct in cases in which the duct cannot be drained by conventional ERCP because of complete obstruction. PMID:24949349

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

Transtracheal single-point stent fixation in posttracheotomy tracheomalacia under cone-beam computer tomography guidance by transmural suturing with the Berci needle – a perspective on a new tool to avoid stent migration of Dumon stents

PubMed Central

Hohenforst-Schmidt, Wolfgang; Linsmeier, Bernd; Zarogoulidis, Paul; Freitag, Lutz; Darwiche, Kaid; Browning, Robert; Turner, J Francis; Huang, Haidong; Li, Qiang; Vogl, Thomas; Zarogoulidis, Konstantinos; Brachmann, Johannes; Rittger, Harald

2015-01-01

Tracheomalacia or tracheobronchomalacia (TM or TBM) is a common problem especially for elderly patients often unfit for surgical techniques. Several surgical or minimally invasive techniques have already been described. Stenting is one option but in general long-time stenting is accompanied by a high complication rate. Stent removal is more difficult in case of self-expandable nitinol stents or metallic stents in general in comparison to silicone stents. The main disadvantage of silicone stents in comparison to uncovered metallic stents is migration and plugging. We compared the operation time and in particular the duration of a sufficient Dumon stent fixation with different techniques in a patient with severe posttracheotomy TM and strongly reduced mobility of the vocal cords due to Parkinson’s disease. The combined approach with simultaneous Dumon stenting and endoluminal transtracheal externalized suture under cone-beam computer tomography guidance with the Berci needle was by far the fastest approach compared to a (not performed) surgical intervention, or even purely endoluminal suturing through the rigid bronchoscope. The duration of the endoluminal transtracheal externalized suture was between 5 minutes and 9 minutes with the Berci needle; the pure endoluminal approach needed 51 minutes. The alternative of tracheobronchoplasty was refused by the patient. In general, 180 minutes for this surgical approach is calculated. The costs of the different approaches are supposed to vary widely due to the fact that in Germany 1 minute in an operation room costs on average approximately 50–60€ inclusive of taxes. In our own hospital (tertiary level), it is nearly 30€ per minute in an operation room for a surgical approach. Calculating an additional 15 minutes for patient preparation and transfer to wake-up room, therefore a total duration inside the investigation room of 30 minutes, the cost per flexible bronchoscopy is per minute on average less than 6€. Although the Dumon stenting requires a set-up with more expensive anesthesiology accompaniment, which takes longer than a flexible investigation estimated at 1 hour in an operation room, still without calculation of the costs of the materials and specialized staff that the surgical approach would consume at least 3,000€ more than a minimally invasive approach performed with the Berci needle. This difference is due to the longer time of the surgical intervention which is calculated at approximately 180 minutes in comparison to the achieved non-surgical approach of 60 minutes in the operation suite. PMID:26045666

An approach to tracheostomy in a patient with an expandable metallic tracheal stent.

PubMed

Madden, Brendan P; Sheth, Abhijat

2005-09-01

With increasing use of expandable metallic stents to manage patients with a variety of endobronchial pathologies, some will have a subsequent need for tracheostomy insertion. We describe a successful technique to insert a tracheostomy using rigid and fibre-optic bronchoscopy in a patient who had an 8 cm expandable metallic tracheal stent deployed previously on account of tracheomalacia.

Comparison of results of endovascular stenting and bypass grafting for TransAtlantic Inter-Society (TASC II) type B, C and D iliac occlusive disease

PubMed Central

Benetis, Rimantas; Antusevas, Aleksandras; Kaupas, Rytis Stasys; Inciura, Donatas; Kinduris, Sarunas

2016-01-01

Introduction The priority use of endovascular techniques in the management of aortoiliac occlusive disease has increased in the last decade. The aim of the present article is to report 1- and 2-year results of iliac artery stenting (IAS) and aortoiliac grafting in the management of patients with TASC II type B, C and D iliac lesions and chronic limb ischaemia. Material and methods In this prospective, non-randomised, one-centre clinical study, iliac artery stents and vascular grafts used for the treatment of patients with symptomatic lesions in the iliac artery were evaluated. This study enrolled 2 groups: 54 patients in the stent group and 47 patient in the surgery group. Results The primary patency rates at 1 and 2 years were 83% and 79.9% after IAS and 97.1% and 97.1% after surgical reconstruction, respectively (p = 0.015). The assisted primary stent patency at 1 and 2 years was 87.9% and 78.2%, respectively. The complication rate was 7.4% in the stent group and 6.3% in the surgery group. There was no perioperative mortality in either group. Conclusions Our results reveal that patients with severe aortoiliac occlusive disease (TASC II types B, C and D) can be treated with IAS or surgically with satisfactory results. Iliac artery stenting is associated with decreased primary patency compared with the surgery group. Iliac artery stenting should be considered with priority in elderly patients or in patients with severe comorbidities. PMID:27186180

Management of occluded self-expanding biliary metal stents in malignant biliary disease.

PubMed

Nennstiel, Simon; Tschurtschenthaler, Isolde; Neu, Bruno; Algül, Hana; Bajbouj, Monther; Schmid, Roland M; von Delius, Stefan; Weber, Andreas

2018-02-01

Occlusion of self-expanding metal stents (SEMS) in malignant biliary obstruction occurs in up to 40% of patients. This study aimed to compare the different techniques to resolve stent occlusion in our collective of patients. Patients with malignant biliary obstruction and occlusion of biliary metal stent at a tertiary referral endoscopic center were retrospectively identified between April 1, 1994 and May 31, 2014. The clinical records were further analyzed regarding the characteristics of patients, malignant strictures, SEMS, management strategies, stent patency, subsequent interventions, survival time and case charges. A total of 108 patients with biliary metal stent occlusion were identified. Seventy-nine of these patients were eligible for further analysis. Favored management was plastic stent insertion in 73.4% patients. Second SEMS were inserted in 12.7% patients. Percutaneous transhepatic biliary drainage and mechanical cleansing were conducted in a minority of patients. Further analysis showed no statistically significant difference in median overall secondary stent patency (88 vs. 143 days, P = 0.069), median survival time (95 vs. 192 days, P = 0.116), median subsequent intervention rate (53.4% vs. 40.0%, P = 0.501) and median case charge (€5145 vs. €3473, P = 0.803) for the treatment with a second metal stent insertion compared to plastic stent insertion. In patients with survival time of more than three months, significantly more patients treated with plastic stents needed re-interventions than patients treated with second SEMS (93.3% vs. 57.1%, P = 0.037). In malignant biliary strictures, both plastic and metal stent insertions are feasible strategies for the treatment of occluded SEMS. Our data suggest that in palliative biliary stenting, patients especially those with longer expected survival might benefit from second SEMS insertion. Careful patient selection is important to ensure a proper decision for either management strategy. Copyright © 2018 First Affiliated Hospital, Zhejiang University School of Medicine in China. Published by Elsevier B.V. All rights reserved.

Hemodynamic comparison of stent configurations used for aortoiliac occlusive disease.

PubMed

Groot Jebbink, Erik; Mathai, Varghese; Boersen, Johannes T; Sun, Chao; Slump, Cornelis H; Goverde, Peter C J M; Versluis, Michel; Reijnen, Michel M P J

2017-07-01

Endovascular treatment of aortoiliac occlusive disease entails the use of multiple stents to reconstruct the aortic bifurcation. Different configurations have been applied and geometric variations exist, as quantified in previous work. Other studies concluded that specific stent geometry seems to affect patency. These variations may affect local flow patterns, resulting in different wall shear stress (WSS) and oscillating shear index (OSI). The aim of this study was to compare the effect of different stent configurations on flow perturbations (recirculation and fluid stasis), WSS, and OSI in an in vitro setup. Three different stent configurations were deployed in transparent silicone models: bare-metal kissing (BMK) stents, covered kissing (CK) stents, and the covered endovascular reconstruction of the aortic bifurcation (CERAB) configuration. Transparent covered stents were created with polyurethane to enable visualization. Models were placed in a circulation setup under physiologic flow conditions. Time-resolved laser particle image velocimetry techniques were used to quantify the flow, and WSS and OSI were calculated. The BMK configuration did not show flow disturbances at the inflow section, and WSS values were similar to the control. An area of persistent low flow was observed throughout the cardiac cycle in the area between the anatomic bifurcation and neobifurcation. The CK model showed recirculation zones near the inflow area of the stents with a resulting low average WSS value and high OSI. The proximal inflow of the CERAB configuration did not show flow disturbances, and WSS values were comparable to control. Near the inflow of the limbs, a minor zone of recirculation was observed without changes in WSS values. Flow, WSS, and OSI on the lateral wall of the proximal iliac artery were undisturbed in all models. The studied aortoiliac stent configurations have distinct locations where flow disturbances occur, and these are related to the radial mismatch. The CERAB configuration is the most unimpaired physiologic reconstruction, whereas BMK and CK stents have their typical zones of flow recirculation. Copyright © 2016 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

Endoscopic Dacrocystorhinostomy in Lacrimal Canalicular Trauma

PubMed Central

Khan, Humayun A; Bayat, Aredeshir; De Carpentier, JP

2007-01-01

A case is presented where the common insertion of the upper and lower canaliculus of the lacrimal sac was repaired using endoscopic dacrocystorhinostomy (DCR) techniques, with silicone stenting and securing of stents intranasally. PMID:17316509

Radiofrequency wire for the recanalization of central vein occlusions that have failed conventional endovascular techniques.

PubMed

Guimaraes, Marcelo; Schonholz, Claudio; Hannegan, Christopher; Anderson, Michael Bret; Shi, June; Selby, Bayne

2012-08-01

To report the technique and acute technical results associated with the PowerWire Radiofrequency (RF) Guidewire used to recanalize central vein occlusions (CVOs) after the failure of conventional endovascular techniques. A retrospective study was conducted from January 2008 to December 2011, which identified all patients with CVOs who underwent treatment with a novel RF guide wire. Forty-two symptomatic patients (with swollen arm or superior vena cava [SVC] syndrome) underwent RF wire recanalization of 43 CVOs, which were then implanted with stents. The distribution of CVOs in central veins was as follows: six subclavian, 29 brachiocephalic, and eight SVC. All patients had a history of central venous catheter placement. Patients were monitored with regular clinical evaluations and central venography after treatment. All 42 patients had successful recanalization of CVOs facilitated by the RF wire technique. There was one complication, which was not directly related to the RF wire: one case of cardiac tamponade attributed to balloon angioplasty after stent placement. Forty of 42 patients (95.2%) had patent stents and were asymptomatic at 6 and 9 months after treatment. The present results suggest that the RF wire technique is a safe and efficient alternative in the recanalization of symptomatic and chronic CVOs when conventional endovascular techniques have failed. Copyright © 2012 SIR. Published by Elsevier Inc. All rights reserved.

Recent advances in endovascular treatment of aortoiliac occlusive disease.

PubMed

Kavaliauskienė, Zana; Antuševas, Aleksandras; Kaupas, Rytis Stasys; Aleksynas, Nerijus

2012-01-01

The rate of endovascular interventions for iliac occlusive lesions is continuously growing. The evolution of the technology supporting these therapeutic measures improves the results of these interventions. We performed a review of the literature to report and appreciate short- and long-term results of endovascular stenting of iliac artery occlusive lesions. The Medline database was searched to identify all the studies reporting iliac artery stenting for aortoiliac occlusive disease (Trans Atlantic Inter-Society Consensus [TASC] type A, B, C, and D) from January 2006 to July 2012. The outcomes were technical success, long-term primary and secondary patency rates, early mortality, and complications. Technical success was achieved in 91% to 99% of patients as reported in all the analyzed articles. Early mortality was described in 5 studies and ranged from 0.7% to 3.6%. The most common complications were access site hematomas, distal embolization, pseudoaneurysms, and iliac artery ruptures. The complications were most often treated conservatively or using percutaneous techniques. The 5-year primary and secondary patency rates ranged from 63% to 88% and 86% to 93%, respectively; and the 10-year primary patency rates ranged from 68% to 83%. In this article, combined percutaneous endovascular iliac stenting and infrainguinal surgical reconstructions and new techniques in the treatment of iliac stent restenosis are discussed. Iliac stenting is a feasible, safe, and effective method for the treatment of iliac occlusive disease. Initial technical and clinical success rates are high; early mortality and complication rates are low. Long-term patency is comparable with that after bypass surgery.

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.

Endoscopic retrograde JJ-stenting of the ureter without fluoroscopy guidance--an appraisal of outcome.

PubMed

Shuaibu, S I; Gidado, S; Oseni-Momodu, E

2013-01-01

JJ- ureteral stenting is a means of relieving ureteric obstruction. It is done as a retrograde or antegrade procedure, usually under fluoroscopy guidance. We reviewed our results in 2 independent tertiary health centers in Nigeria which lack fluoroscopy units. A 2 year retrospective review of data of patients who had retrograde JJ- ureteric stenting was done. Data relating to age, indication and outcome of procedure were retrieved and analysed. 22 (71%) patients had successful retrograde JJ- ureteric stenting out of 31 patients who were taken for the procedure. These 22 patients had stenting of 27 ureteric units. Mean age was 48.5 years. Commonest indication was carcinoma of the cervix (31.8%). Commonest complication was irritative lower urinary tract symptoms (43.5%). In spite of inherent complications, JJ-stenting is a simple and safe technique. Therefore, the decision to attempt JJ -stenting in carefully selected patients in the absence of fluoroscopy is acceptable.

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.

[Feasibility and possibility of Inoue stent graft for thoracic aortic aneurysms].

PubMed

Marui, Akira; Kimura, Takeshi; Tazaki, Junichi; Sakata, Ryuzo; Inoue, Kanji

2011-01-01

Open surgical repair is a traditional treatment for patients with thoracic aortic aneurysms. Despite recent advances in surgical techniques and anesthetic management, the surgical repair of thoracic aortic aneurysms is still associated with significant mortality and morbidity. Endovascular aneurysm repair of thoracic aortic aneurysms is emerging as an alternative method for repair in selected patients. Although endovascular stent grafting is less invasive than open surgical repair, involvement of branch vessels and precipitous curvature of the aortic arch limits the application of stent grafting. Inoue stent graft system consists of soft nitinol ring-type stent which enables very flexible stent graft, and it can well comply with the precipitous curvature of the aortic arch. The system also provides a stent graft with a side branch to manage the left subclavian artery. This system does not require the surgical revascularization of the left subclavian artery. In this report, we show the feasibility and possibility of Inoue stent graft system to manage the aortic arch aneurysm.

[Myocardial ischemia in general medicine and the revolution of coronary stents].

PubMed

El-Mourad, M; Merveille, P; Preumont, N

2014-09-01

Since Gruentizg's first percutaneous transluminal ballon angioplasty in 1977 in Zurich, percuta. neous coronary intervention evolved significantly in order to overcome the numerous associated complications of each technique. Bare-metal stents (BMS) made their initial appearance followed by three generations of drug-eluting stents (DES). The use of bioabsorbable vascular scaffold stents (BVS) has become more frequent creating a temporary scaffold allowing healing of the endothelium within 2 years. In this article, we discuss the nomenclature of the main intravascular complications linked to percuta. neous coronary intervention such as stent thrombosis (ST), Instent restenosis (ISR), neoatherosclerosis, and stents evolution to overcome these complications. We will finally mention the new technologies of intracoronary imaging such as OCT (Optical Coherence Tomography) having an increasing vital role in percutaneous coronary intervention,

Complications of Nonoperative Management of High-grade Blunt Hepatic Injuries

DTIC Science & Technology

2005-11-01

cholangiopancreatography (ERCP) and stenting of biliary leaks, and CT scan-guided drainage of hepatic or perihepatic abscesses or biliary collections by...1 B). Stenting was successful in decreasing the biliary leak, but repeat ERCP was required for increased serum bilirubin, pain, and fever...Finally, failure of percutaneous drainage techniques or biliary stenting may require operative intervention. In summary, although patients with high

An Assessment of Radiologically Inserted Transoral and Transgastric Gastroduodenal Stents to Treat Malignant Gastric Outlet Obstruction

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

Miller, Bethany H. T., E-mail: bmiller@doctors.org.uk; Griffiths, Ewen A., E-mail: Eagriffiths@doctors.org.uk; Pursnani, Kishore G., E-mail: Kish.Pursnani@lthtr.nhs.uk

2013-12-15

IntroductionSelf-expanding metallic stents (SEMS) are used to palliate malignant gastric outlet obstruction (GOO) and are useful in patients with limited life expectancy or severe medical comorbidity, which would preclude surgery. Stenting can be performed transorally or by a percutaneous transgastric technique. Our goal was to review the outcome of patients who underwent radiological SEMS insertion performed by a single consultant interventional radiologist. Methods: Patients were identified from a prospectively collected database held by one consultant radiologist. Data were retrieved from radiological reports, multidisciplinary team meetings, and the patients' case notes. Univariate survival analysis was performed. Results: Between December 2000 andmore » January 2011, 100 patients (63 males, 37 females) had 110 gastroduodenal stenting procedures. Median age was 73 (range 39-89) years. SEMS were inserted transorally (n = 66) or transgastrically (n = 44). Site of obstruction was the stomach (n = 37), duodenum (n = 50), gastric pull-up (n = 10), or gastroenterostomy (n = 13). Seven patients required biliary stents. Technical success was 86.4 %: 83.3 % for transoral insertion, 90.9 % for transgastric insertion. Eleven patients developed complications. Median GOO severity score: 1 pre-stenting, 2 post-stenting (p = 0.0001). Median survival was 54 (range 1-624) days. Post-stenting GOO severity score was predictive of survival (p = 0.0001). Conclusions: The technical success rate for insertion of palliative SEMS is high. Insertional technique can be tailored to the individual depending on the location of the tumor and whether it is possible to access the stomach percutaneously. Patients who have successful stenting and return to eating a soft/normal diet have a statistically significant increase in survival.« less

Rescue strategy for acute carotid stent thrombosis during carotid stenting with distal filter protection using forced arterial suction thrombectomy with a reperfusion catheter of the Penumbra System: a technical note.

PubMed

Kim, Yong-Won; Kang, Dong-Hun; Hwang, Jeong-Hyun; Park, Jaechan; Hwang, Yang-Ha; Kim, Yong-Sun

2013-08-01

Among the procedural complications related to carotid artery stenting (CAS), internal carotid artery (ICA) flow arrest is one of the most drastic complications, as it can cause major ischemic stroke. Acute carotid stent thrombosis (ACST) is a rare etiology of ICA flow arrest during carotid artery stenting with distal filter protection, but the most devastating. Moreover, no definitive management strategy has been established so far for treating ACST. We introduce a rescue management strategy for differential diagnosis of ICA flow arrest and for recanalization of ACST with a simple endovascular mechanical thrombectomy technique. In three cases of ICA flow arrest caused by ACST, selective angiography with a 1.7 F microcatheter provided confirmative diagnosis. Recanalization was then achieved with a Penumbra System (PS) reperfusion catheter using the forced arterial suction thrombectomy (FAST) technique. Successful recanalization with a Thrombolysis In Cerebral Infarction score of 3 was achieved for all three patients. Recanalization was confirmed with follow-up angiography at least 24 h after the procedure. No complications associated with this technique occurred. Based on our preliminary experiences, selective microangiography can be helpful for rapid diagnosis of ACST, and the present mechanical thrombectomy technique, using a modification of the PS, can play a role in adjuvant management or as a last resort for the treatment of ACST during CAS.

High-definition computed tomography for coronary artery stents imaging compared with standard-definition 64-row multidectector computed tomography: an initial in vivo study.

PubMed

Yang, Wen Jie; Zhang, Huan; Xiao, Hua; Li, Jian Ying; Liu, Yan; Pan, Zi Lai; Chen, Ke Min

2012-01-01

The evaluation of coronary stents by computed tomography (CT) remains difficult. We assessed the imaging performance of a high-definition CT scanner (HDCT) by comparing with a conventional 64-row standard-definition CT (SDCT). One hundred thirty-eight consecutive stented patients underwent coronary CT angiography, among whom 66 patients were examined by HDCT, and 72 patients by SDCT (LightSpeed VCT XT; GE Healthcare, Waukesha, Wis). The image quality score, the inner stent diameter (ISD), and the radiation dose were analyzed. All data were statistically tested by SPSS 13.0 software (SPSS Inc, Chicago, Ill). In 72 patients examined using SDCT, 135 stents were detected; in 66 patients examined using HDCT, 119 stents were detected. The image quality score on HDCT was significantly better than that on SDCT (1.4 [SD, 0.7] vs 1.9 [SD, 0.8]). The ISD on HDCT was significantly higher than that on SDCT (1.8 [SD, 0.5] vs 1.6 [SD, 0.4]). There was no significant difference of either image quality score or ISD between the HDCT and SDCT groups in stents with 2.5-mm diameter. Images on HDCT showed significantly better image quality score and larger ISD than images on SDCT in 2.75-, 3-, and 3.5-mm stents. For patients examined by retrospective electrocardiogram-gated technique, the radiation dose on HDCT was significantly lower than that on SDCT (11.3 [SD, 2.9] vs 15.1 [SD, 3.8] mSv). High-definition CT scanner offered improved image quality and measurement accuracy for imaging coronary stents compared with conventional SDCT, providing higher spatial resolution and lower dose for evaluating coronary stents with 2.75- to 3.5-mm diameter.

Intracoronary beta-radiation for the treatment of patients at very high risk for recurrence of in-stent restenosis: a single center experience.

PubMed

Parenti, Dennis Zavalloni; Marsico, Federica; Tosi, Giovanni; Catalano, Gianpiero; Maiello, Luigi; Milone, Francesco; Carcagnì, Addolorata; Pron, Paolo Giay; Orecchia, Roberto; Presbitero, Patrizia

2003-03-01

Intracoronary brachytherapy has significantly reduced the recurrence of in-stent restenosis. The aim of this study was to evaluate the feasibility, safety and efficacy of intracoronary beta-radiation in patients at very high risk for recurrence of in-stent restenosis. We analyzed 42 patients with 50 lesions submitted to catheter-based beta-radiation (Beta-Cath System, Novoste Corporation, Norcross, GA, USA) for in-stent restenosis. Thirty-eight lesions were at the second restenosis, 8 at the third, and 4 at the fourth; a diffuse pattern was present in 78%. Balloon angioplasty was performed for 30 lesions (60%) and the cutting balloon technique for 20 (40%). In 12 lesions further 14 stents had to be deployed (28%). The delivery catheter was successfully positioned in 96% of the procedures. The mean dwell time was 179 +/- 50 s with a radiation dose ranging from 18.4 to 25.3 Gy, depending on the vessel size. A complete angiographic success without coronary dissection and without any additional stenting after radiation delivery was achieved in 86%. At follow-up (7.2 +/- 2.1 months), the overall restenosis rate was 30.4% (14 lesions). A recurrence was detected in 1/11 lesions with initial focal pattern and in 13/39 lesions with initial diffuse pattern. The restenosis rate was higher in patients in whom a geographic miss had occurred (p < 0.05 vs lesions without geographic miss) and in those in whom a new stent had been deployed (p < 0.05 vs lesions treated without a stent). Brachytherapy reduces the in-stent restenosis rate in patients who are at very high risk of recurrence. The restenosis pattern, geographic miss and new stent deployment seem to be negative prognostic factors for recurrence of restenosis.

Stent-thrombus interaction and the influence of aspiration on mechanical thrombectomy: evaluation of different stent retrievers in a circulation model.

PubMed

Madjidyar, Jawid; Hermes, Julian; Freitag-Wolf, Sandra; Jansen, Olav

2015-08-01

Different devices and techniques are available for endovascular treatment of ischemic stroke. In this in vitro study, we examined the stent-thrombus interaction and the influence of additional aspiration on the efficiency of mechanical thrombectomy with established stent retrievers. Human blood thrombi were made in a Chandler loop. The thrombi were placed into the middle cerebral artery of a vascular silicon phantom. A programmable piston pump was used to acquire physiological flow in the model. Resistances were interposed to gain physiological pressure. The stent retrievers Trevo, Solitaire FR, Separator 3D, and Aperio were used to perform thrombectomy under direct visual control. For the additional aspiration, we used intermediate catheters. Ten attempts per device were made with and without aspiration under standardized conditions, a total of n = 80. For all thrombectomy maneuvers, it was demonstrated that the thrombus was pushed by the stent struts against the vessel wall and was retracted along it. The stent-thrombus interaction was only superficial for all devices. Using additional distal aspiration, the amount of distal embolism and rate of embolism in new territories was significantly lower than without. Moreover, additional aspiration reduced the number of recanalization maneuvers and the recanalization time. Distal aspiration with intermediate catheters increases the efficacy of mechanical thrombectomy with stent retrievers significantly. In contrary to earlier suggestions, the interaction between the thrombus and the stent retriever is only superficial, rather than an integration of the thrombus into the retriever. No significant differences between the proven devices could be shown in our model.

[Proposed model of vascular trauma by mean of mechanical characterization of endovascular prostheses (stents) based on structural analysis by FEA].

PubMed

Bustamante, John; Uribe, Pablo; Sosa, Mauricio; Valencia, Raúl

2016-01-01

The accumulated evidence on angioplasty techniques with stents has raised a controversy about the factors that influence the final vascular response. Indeed, several studies have shown there might be re-stenosis between 30% to 40% about 6 months after placement, relating to the design of the device as one of the main causes. This paper proposes the functional characterization of endovascular stents, analyzing its mechanical influence in the vascular system and predicting implicit traumatic factors in the vessel. A structural analysis was made for several computational models of endovascular stents using Finite Element Analysis in order to predict the mechanical behavior and the vascular trauma. In this way, the stents were considered as tubular devices composed of multiple links under radial pressure loads, reflecting stress concentration effects. The analysis allowed to visualize how the geometry of stents is adjusted under several load conditions, in order to obtain the response of "solid-solid" interaction between the stent and the arterial wall. Thus, an analysis was performed in order to calculate stress, and a conceptual model that explains its mechanical impact on the stent-vessel interaction, was raised, to infer on the functionality from the design of the devices. The proposed conceptual model allows to determine the relationship between the conditions of mechanical interaction of the stents, and warns about the effects in what would be the operation of the device on the vascular environment. Copyright © 2016 Instituto Nacional de Cardiología Ignacio Chávez. Publicado por Masson Doyma México S.A. All rights reserved.

High-definition computed tomography for coronary artery stent imaging: a phantom study.

PubMed

Yang, Wen Jie; Chen, Ke Min; Pang, Li Fang; Guo, Ying; Li, Jian Ying; Zhang, Huang; Pan, Zi Lai

2012-01-01

To assess the performance of a high-definition CT (HDCT) for imaging small caliber coronary stents (≤ 3 mm) by comparing different scan modes of a conventional 64-row standard-definition CT (SDCT). A cardiac phantom with twelve stents (2.5 mm and 3.0 mm in diameter) was scanned by HDCT and SDCT. The scan modes were retrospective electrocardiography (ECG)-gated helical and prospective ECG-triggered axial with tube voltages of 120 kVp and 100 kVp, respectively. The inner stent diameters (ISD) and the in-stent attenuation value (AV(in-stent)) and the in-vessel extra-stent attenuation value (AV(in-vessel)) were measured by two observers. The artificial lumen narrowing (ALN = [ISD - ISD(measured)]/ISD) and artificial attenuation increase between in-stent and in-vessel (AAI = AV(in-stent) - AV(in-vessel)) were calculated. All data was analyzed by intraclass correlation and ANOVA-test. The correlation coefficient of ISD, AV(in-vessel) and AV(in-stent) between the two observers was good. The ALNs of HDCT were statistically lower than that of SDCT (30 ± 5.7% versus 35 ± 5.4%, p < 0.05). HDCT had statistically lower AAI values than SDCT (15.7 ± 81.4 HU versus 71.4 ± 90.5 HU, p < 0.05). The prospective axial dataset demonstrated smaller ALN than the retrospective helical dataset on both HDCT and SDCT (p < 0.05). Additionally, there were no differences in ALN between the 120 kVp and 100 kVp tube voltages on HDCT (p = 0.05). High-definition CT helps improve measurement accuracy for imaging coronary stents compared to SDCT. HDCT with 100 kVp and the prospective ECG-triggered axial technique, with a lower radiation dose than 120 kVp application, may be advantageous in evaluating coronary stents with smaller calibers (≤ 3 mm).

[Comparison of the therapeutic effects of PTBD and PTBS in treatment of malignant obstructive jaundice].

PubMed

Bai, Ai-Guo; Zheng, Chuan-Sheng; Zhou, Guo-Feng; Liang, Hui-Min; Feng, Gan-Sheng

2010-06-01

To summarize and compare the short-term and long-term clinical efficacy of percutaneous transhepatic biliary drainage (PTBD) and percutaneous transhepatic biliary stent (PTBS) in the treatment of malignant obstructive jaundice. 210 cases of malignant obstructive jaundice underwent interventional therapy, of which 161 cases of drainage catheters placement and 49 cases of metallic stent implantation. Follow-up information was obtained through telephone review or check-up records. The technical success rate of technique was 100%. At 3 - 5 days after treatment, the serum total bilirubin in 15 metallic stent-treated patients was decreased by (178.04 +/- 42.32) micromol/L, and direct bilirubin by (83.97 +/- 23.63) micromol/L. Compared with those of 28 cases treated with drainage catheters: (95.67 +/- 34.28) micromol/L and (49.84 +/- 28.21) micromol/L, there were statistically significant differences between the two groups (P = 0.017 and P = 0.035). At 6 - 9 days after treatment, the serum total bilirubin in 28 cases of metallic stent group was decreased by (188.22 +/- 79.90) micromol/L, and that in 126 cases of drainage catheter group decreased by (141.39 +/- 65.32) micromol/L. The difference was statistically significant (P = 0.014). But the decline value of direct bilirubin had no significant difference. The median patency period and the median survival time of the drainage catheter group were 60 and 148 days, respectively, those of metallic stent group were 197 days and 245 days. There were statistically significant differences between the two groups (P < 0.05). The results of this study indicate that the short-term and long-term efficacies of metallic stent implantation are better than those of catheter drainage technique.

Clipping in Awake Surgery as End-Stage in a Complex Internal Carotid Artery Aneurysm After Failure of Multimodal Endovascular and Extracranial-Intracranial Bypass Treatment.

PubMed

Cannizzaro, Delia; Peschillo, Simone; Mancarella, Cristina; La Pira, Biagia; Rastelli, Emanuela; Passacantilli, Emiliano; Santoro, Antonio

2017-06-01

Intracranial carotid artery aneurysm can be treated via microsurgical or endovascular techniques. The optimal planning is the result of the careful patient selection through clinical, anatomic, and angiographic analysis. We present a case of ruptured internal carotid artery (ICA) aneurysm that became a complex aneurysm after failure of multi-endovascular and surgery treatment. We describe complete trapping in awake craniotomy after failure of coiling, stenting, and bypassing. ICA aneurysms could become complex aneurysms following multi-treatment failure. Endovascular approaches to treat ICA aneurysms include coiling, stenting, flow diverter stenting, and stenting-assisted coiling technique. The role of surgery remains relevant. To avoid severe neurologic deficits, recurrence, and the need of retreatment, a multidisciplinary discussion with experienced endovascular and vascular neurosurgeons is mandatory in such complex cases. Copyright © 2017 National Stroke Association. Published by Elsevier Inc. All rights reserved.

Palliation: Hilar cholangiocarcinoma

PubMed Central

Goenka, Mahesh Kr; Goenka, Usha

2014-01-01

Hilar cholangiocarcinomas are common tumors of the bile duct that are often unresectable at presentation. Palliation, therefore, remains the goal in the majority of these patients. Palliative treatment is particularly indicated in the presence of cholangitis and pruritus but is often also offered for high-grade jaundice and abdominal pain. Endoscopic drainage by placing stents at endoscopic retrograde cholangio-pancreatography (ERCP) is usually the preferred modality of palliation. However, for advanced disease, percutaneous stenting has been shown to be superior to endoscopic stenting. Endosonography-guided biliary drainage is emerging as an alternative technique, particularly when ERCP is not possible or fails. Metal stents are usually preferred over plastic stents, both for ERCP and for percutaneous biliary drainage. There is no consensus as to whether it is necessary to place multiple stents within advanced hilar blocks or whether unilateral stenting would suffice. However, recent data have suggested that, contrary to previous belief, it is useful to drain more than 50% of the liver volume for favorable long-term results. In the presence of cholangitis, it is beneficial to drain all of the obstructed biliary segments. Surgical bypass plays a limited role in palliation and is offered primarily as a segment III bypass if, during a laparotomy for resection, the tumor is found to be unresectable. Photodynamic therapy and, more recently, radiofrequency ablation have been used as adjuvant therapies to improve the results of biliary stenting. The exact technique to be used for palliation is guided by the extent of the biliary involvement (Bismuth class) and the availability of local expertise. PMID:25232449

Efficacy of a Self-Expandable Porous Stent as the Sole Curative Treatment for Extracranial Carotid Pseudoaneurysms.

PubMed

Chen, Peng Roc; Edwards, Nancy J; Sanzgiri, Aditya; Day, Arthur L

2016-04-01

Extracranial carotid pseudoaneurysms are uncommon vascular lesions. Even with conservative management complications can happen, such as delayed cerebral embolization or symptoms due to flow limitation. Although endovascular therapy can be curative, literature demonstrating a preferred technique is scant. Our goal was to evaluate the use of 1 technique only-the deployment of overlapping self-expandable porous stents-to treat a series of extracranial carotid pseudoaneurysms. From 2008 to 2014, 14 consecutive cases of symptomatic extracranial carotid pseudoaneurysms were managed with single or multilayer porous stents at our institution. Each patient underwent a standardized angiographic follow-up at 6 months. Twelve patients also received a follow-up computed tomography angiogram at 12 months, and yearly thereafter (median radiographic follow-up, 38 months). The total clinical follow-up period ranged between 6 and 69 months (median, 46 months). In our series, each of the extracranial carotid pseudoaneurysms appeared to be the result of carotid artery dissection with associated carotid stenosis at the origin of every pseudoaneurysm. Endovascular treatment consisted of 1-3 layers of self-expandable porous stents placed without balloon angioplasty. Immediately after stenting angiographic images were notable for stagnant opacification of the pseudoaneurysm through the stent(s). All pseudoaneurysms were completely obliterated by the 6-month follow-up angiogram and remained so throughout the radiographic follow-up period. Complications were minimal, consisting of 1 patient developing a mild Horner's syndrome after treatment that resolved during clinical follow-up. Extracranial carotid pseudoaneurysms can be successfully obliterated with the use of porous, self-expandable stents. Copyright © 2016 Elsevier Inc. All rights reserved.

Concurrent Angioplasty Balloon Placement for Stent Delivery through Jugular Venous Bulb for Treating Cerebral Venous Sinus Stenosis. Technical Report.

PubMed

Qureshi, Adnan I; Khan, Asif A; Capistrant, Rachel; Qureshi, Mushtaq H; Xie, Kevin; Suri, M Fareed K

2016-10-01

To report upon technique of concurrent placement of angioplasty balloon at the internal jugular vein and sigmoid venous sinus junction to facilitate stent delivery in two patients in whom stent delivery past the jugular bulb was not possible. A 21-year-old woman and a 41-year-old woman with worsening headaches, visual obscuration or diplopia were treated for pseudotumor cerebri associated with transverse venous stenosis. Both patients had undergone primary angioplasty, which resulted in improvement in clinical symptoms followed by the recurrence of symptoms with restenosis at the site of angioplasty. After multiple attempts at stent delivery through jugular venous bulb were unsuccessful, a second guide catheter was placed in the ipsilateral internal jugular vein through contralateral femoral venous approach. A 6 mm × 20 mm (left) or 5 × 15 mm (right) angioplasty balloon was placed across the internal jugular vein and sigmoid sinus junction and partially inflated until the inflation and relative straightening of the junction was observed. In both patients, the internal jugular vein and sigmoid sinus junction was successfully traversed by the stent delivery system in a parallel alignment to inflated balloon. Balloon mounted stent was deployed at the site of restenosis with near complete resolution of lumen narrowing delivery and improvement in clinical symptoms. We report a technique for realignment and diameter change with concurrent placement and partial inflation of angioplasty balloon at the jugular venous bulb to facilitate stent delivery into the sigmoid and transverse venous sinuses in circumstances where multiple attempts at stent delivery are unsuccessful.

Metallic stents for tracheobronchial pathology treatment.

PubMed

Serrano, Carolina; Laborda, Alicia; Lozano, Juan M; Caballero, Hugo; Sebastián, Antonio; Lopera, Jorge; de Gregorio, Miguel Ángel

2013-12-01

To present the 7-year experience of the treatment of benign and malignant tracheobronchial stenoses using metallic stents. One hundred twenty-three stents were inserted in 86 patients (74 benign and 12 malignant stenoses). Ninety-seven stents were placed in the trachea and 26 in the bronchi. The procedures were performed under fluoroscopic and flexible bronchoscopic guidance with the patient under light sedation. In cases of severe stenotic lesions or obstructions, laser resection was performed before stent placement. Clinical and functional pulmonary data were recorded before and 3 months after the procedure. Follow-up involved clinical data and radiographic techniques at 48 h and at 1-, 3-, 6-, and 12-month intervals. The technical success was 100 %. Dyspnea disappearance, forced expiratory volume in the first second, and pulmonary functional data improvement was observed in all patients (p < 0.001). Complications were detected in 23 patients (26.7 %). Mean follow-up time was 6.3 ± 1.2 months in patients with malignant lesions and 76.2 ± 2.3 months patients with in benign lesions. By the end of the study, 100 % of patients with malignant pathology and 6.7 % of patients with benign lesions had died. Endoluminal treatment of tracheobronchial stenosis with metallic stents is a therapeutic alternative in patients who are poor candidates for surgery. In unresectable malignant lesions, the benefit of metallic stenting is unquestionable. In benign lesions, the results are satisfactory, but sometimes other interventions are required to treat complications. New stent technology may improve these results.

Transradial percutaneous coronary intervention for left main bifurcation lesions using 7.5-Fr sheathless guide catheter.

PubMed

Zhao, Huiqiang; Banerjee, Subhash; Chen, Hui; Li, Hongwei

2018-05-01

Recent studies have shown sheathless guide catheters (GCs) to be safe and effective during complex lesions such as bifurcations, chronic total occlusion (CTO), and/or calcified lesions. We investigated the feasibility and safety of using 7.5-Fr sheathless GC for transradial percutaneous coronary intervention (PCI) to treat left main bifurcation lesions.A total of 82 patients were consecutively enrolled from March 2013 to February 2016. They underwent transradial PCI for left main bifurcation lesions using the 7.5-Fr sheathless GC.The mean syntax score was 28.1 ± 6.1, and the majority (n = 55, 67.1%) was intermediate scores (23∼32). The unprotected LM disease was present in 67 of 82 patients (81.7%), and true bifurcation (Medina 1, 1, 1) was present in 46 of 82 patients (56.1%). The 2-stent technique was used in 62 of 82 patients (75.6%). The 2-stent technique included 31 cases (37.8%) of "Crush," 18 cases (22.0%) of "Cullote," and 13 (15.8%) cases of "T stent and modified T stent" (T stent). Immediate angiographic success rate was 100% (82/82), and procedural success rate was 97.6% (80/82). The vascular complications occurred in 3 patients (3/82, 3.7%).The use of 7.5-Fr sheathless GC is safe and allows PCI for complex bifurcation lesions located in the distal of left main to be performed transradially with a high success rate.

Automatic quantitative analysis of in-stent restenosis using FD-OCT in vivo intra-arterial imaging.

PubMed

Mandelias, Kostas; Tsantis, Stavros; Spiliopoulos, Stavros; Katsakiori, Paraskevi F; Karnabatidis, Dimitris; Nikiforidis, George C; Kagadis, George C

2013-06-01

A new segmentation technique is implemented for automatic lumen area extraction and stent strut detection in intravascular optical coherence tomography (OCT) images for the purpose of quantitative analysis of in-stent restenosis (ISR). In addition, a user-friendly graphical user interface (GUI) is developed based on the employed algorithm toward clinical use. Four clinical datasets of frequency-domain OCT scans of the human femoral artery were analyzed. First, a segmentation method based on fuzzy C means (FCM) clustering and wavelet transform (WT) was applied toward inner luminal contour extraction. Subsequently, stent strut positions were detected by utilizing metrics derived from the local maxima of the wavelet transform into the FCM membership function. The inner lumen contour and the position of stent strut were extracted with high precision. Compared to manual segmentation by an expert physician, the automatic lumen contour delineation had an average overlap value of 0.917 ± 0.065 for all OCT images included in the study. The strut detection procedure achieved an overall accuracy of 93.80% and successfully identified 9.57 ± 0.5 struts for every OCT image. Processing time was confined to approximately 2.5 s per OCT frame. A new fast and robust automatic segmentation technique combining FCM and WT for lumen border extraction and strut detection in intravascular OCT images was designed and implemented. The proposed algorithm integrated in a GUI represents a step forward toward the employment of automated quantitative analysis of ISR in clinical practice.

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

Nam, Hyeong Soo; Kim, Chang-Soo; Yoo, Hongki, E-mail: kjwmm@korea.ac.kr, E-mail: hyoo@hanyang.ac.kr

Purpose: Intravascular optical coherence tomography (IV-OCT) is a high-resolution imaging method used to visualize the microstructure of arterial walls in vivo. IV-OCT enables the clinician to clearly observe and accurately measure stent apposition and neointimal coverage of coronary stents, which are associated with side effects such as in-stent thrombosis. In this study, the authors present an algorithm for quantifying stent apposition and neointimal coverage by automatically detecting lumen contours and stent struts in IV-OCT images. Methods: The algorithm utilizes OCT intensity images and their first and second gradient images along the axial direction to detect lumen contours and stent strutmore » candidates. These stent strut candidates are classified into true and false stent struts based on their features, using an artificial neural network with one hidden layer and ten nodes. After segmentation, either the protrusion distance (PD) or neointimal thickness (NT) for each strut is measured automatically. In randomly selected image sets covering a large variety of clinical scenarios, the results of the algorithm were compared to those of manual segmentation by IV-OCT readers. Results: Stent strut detection showed a 96.5% positive predictive value and a 92.9% true positive rate. In addition, case-by-case validation also showed comparable accuracy for most cases. High correlation coefficients (R > 0.99) were observed for PD and NT between the algorithmic and the manual results, showing little bias (0.20 and 0.46 μm, respectively) and a narrow range of limits of agreement (36 and 54 μm, respectively). In addition, the algorithm worked well in various clinical scenarios and even in cases with a low level of stent malapposition and neointimal coverage. Conclusions: The presented automatic algorithm enables robust and fast detection of lumen contours and stent struts and provides quantitative measurements of PD and NT. In addition, the algorithm was validated using various clinical cases to demonstrate its reliability. Therefore, this technique can be effectively utilized for clinical trials on stent-related side effects, including in-stent thrombosis and in-stent restenosis.« less

The BioStent: novel concept for a viable stent structure.

PubMed

Weinandy, Stefan; Rongen, Lisanne; Schreiber, Fabian; Cornelissen, Christian; Flanagan, Thomas Cormac; Mahnken, Andreas; Gries, Thomas; Schmitz-Rode, Thomas; Jockenhoevel, Stefan

2012-09-01

Percutaneous stenting of occluded peripheral vessels is a well-established technique in clinical practice. Unfortunately, the patency rates of small-caliber vessels after stenting remain unsatisfactory. The aim of the BioStent concept is to overcome in-stent restenosis by excluding the diseased vessel segment entirely from the blood stream, in addition to providing an intact endothelial cell layer. The concept combines the principles of vascular tissue engineering with a self-expanding stent: casting of the stent within a cellularized fibrin gel structure, followed by bioreactor conditioning, allows complete integration of the stent within engineered tissue. Small-caliber BioStents (Ø=6 mm; n=4) were produced by casting a nitinol stent within a thin fibrin/vascular smooth muscle cell (vSMC) mixture, followed by luminal endothelial cell seeding, and conditioning of the BioStent within a bioreactor system. The potential remodeling of the fibrin component into tissue was analyzed using routine histological methods. Scanning electron microscopy was used to assess the luminal endothelial cell coverage following the conditioning phase and crimping of the stent. The BioStent was shown to be noncytotoxic, with no significant effect on cell proliferation. Gross and microscopic analysis revealed complete integration of the nitinol component within a viable tissue structure. Hematoxylin and eosin staining revealed a homogenous distribution of vSMCs throughout the thickness of the BioStent, while a smooth, confluent luminal endothelial cell lining was evident and not significantly affected by the crimping/release process. The BioStent concept is a platform technology offering a novel opportunity to generate a viable, self-expanding stent structure with a functional endothelial cell lining. This platform technology can be transferred to different applications depending on the luminal cell lining required.

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.

CE-MRA for Follow-up of Aneurysms Post Stent-Assisted Coiling

PubMed Central

Agid, R.; Schaaf, M.; Farb, RI.

2012-01-01

Summary This study compared the accuracy of contrast-enhanced MR angiography (CE-MRA) to intra-arterial cerebral angiography (IA-DSA) for assessment of intracranial aneurysms after stent-assisted coiling and to check if the presence of a stent in the parent artery diminishes the accuracy of CE-MRA. Consecutive patients with cerebral aneurysms treated by stent-assisted coiling were evaluated retrospectively. Matching follow-up CE-MRA and IA-DSA were evaluated separately. Evaluation included the presence of aneurysmal remnant, patency and stenosis of parent artery. Twenty-seven patients with 28 aneurysms and 33 matched CE-MRA and IA-DSA studies were evaluated. Nineteen aneurysmal remnants were seen on CE-MRA and 16 on IA-DSA. CE-MRA diagnosed three aneurysmal remnants not appreciated on IA-DSA. Five other remnants were larger on CE-MRA than IA-DSA. None of the remnants were missed on CE-MRA. Parent arteries were patent on both modalities. CE-MRA showed false stenosis of the stented artery in six cases and exaggerated stenosis in two. In 18 cases, CE-MRA showed a short focal “pseudo-stenosis” where the stent’s marker bands were located. This was noted whenever the stent’s marker bands were located in an artery with luminal diameter ≤2 mm and was called “marker band effect”. CE-MRA is an accurate technique for follow-up of aneurysms post stent-assisted coiling with excellent depiction of remnants in spite of the presence of a stent. Apparent stenosis of the stented parent artery on CE-MRA is often false or exaggerated. “Marker band effect” should be recognized as an artifact that appears when stent’s marker bands are in a small artery. PMID:22958765

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.

Assessment of tissue blood flow following small artery welding with an intraluminal dissolvable stent.

PubMed

He, F C; Wei, L P; Lanzetta, M; Owen, E R

1999-01-01

Using the technique of radioactive 51Cr-labeled biological microspheres, this study evaluated arterial blood flow following small vessel anastomosis by CO2 laser welding and a dissolvable stent in the lumen. A total of 30 Sprague-Dawley rats were divided into two groups. Group A: 11 rats had their femoral arteries ligated on one side. The contralateral side served as a control, with the artery transected and repaired using conventional microsuturing. Group B: 19 rats had their femoral arteries transected and repaired using CO2 laser welding and an intraluminal dissolvable stent technique. The contralateral side was again used as a control using conventional microsuturing. At 1 hr postoperatively, 51Cr-labeled biological microspheres were injected centripetally into the left common carotid artery and the legs and thighs immediately harvested for measurement of radioactivity. All repaired arteries were patent (30/30 in the microsuturing group and 19/19 in the stented welding group), with no detectable stenosis or dilation at the repaired site. Statistical analysis showed that tissue radioactivity (cpm/g) in the ligated group (3,972 +/- 384 in thighs and 3,142 +/- 742 in legs) was significantly lower than in the microsuturing group (7,132 +/- 1,723 in thighs and 6,557 +/- 1,469 in legs) (P < 0.01). In the ligated group, a significant reduction of blood flow was seen in the legs when compared with the thighs (P < 0.05). There was no significant difference in radioactivity when comparing the microsuturing control with the stented welding group, in both thighs (7,064 +/- 2,599 and 7,006 +/- 2,406, respectively; P > 0.05) and legs (6,386 +/- 1,703 and 6,288 +/- 1,757, respectively; P > 0.05). This study provided evidence that the dissolvable stent placed intraluminally does not impair blood circulation and that when coupled with CO2 laser welding offers a high-quality alternative to conventional small vessel anastomosis.

Applying value stream mapping techniques to eliminate non-value-added waste for the procurement of endovascular stents.

PubMed

Teichgräber, Ulf K; de Bucourt, Maximilian

2012-01-01

OJECTIVES: To eliminate non-value-adding (NVA) waste for the procurement of endovascular stents in interventional radiology services by applying value stream mapping (VSM). The Lean manufacturing technique was used to analyze the process of material and information flow currently required to direct endovascular stents from external suppliers to patients. Based on a decision point analysis for the procurement of stents in the hospital, a present state VSM was drawn. After assessment of the current status VSM and progressive elimination of unnecessary NVA waste, a future state VSM was drawn. The current state VSM demonstrated that out of 13 processes for the procurement of stents only 2 processes were value-adding. Out of the NVA processes 5 processes were unnecessary NVA activities, which could be eliminated. The decision point analysis demonstrated that the procurement of stents was mainly a forecast driven push system. The future state VSM applies a pull inventory control system to trigger the movement of a unit after withdrawal by using a consignment stock. VSM is a visualization tool for the supply chain and value stream, based on the Toyota Production System and greatly assists in successfully implementing a Lean system. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

Endoscopic stenting versus surgical colostomy for the management of malignant colonic obstruction: comparison of hospital costs and clinical outcomes.

PubMed

Varadarajulu, Shyam; Roy, Ann; Lopes, Tercio; Drelichman, Ernesto R; Kim, Micheline

2011-07-01

Although stent placement is increasingly performed, colostomy still is considered the gold standard for emergent relief of malignant colonic obstruction (MCO). This study aimed to compare hospital costs and clinical outcomes between patients undergoing colostomy and those undergoing stenting for the management of MCO. A retrospective claims analysis of the Medicare Provider Analysis and Review (MedPAR) data set was conducted to identify inpatient hospitalizations for colostomy or stent placement for the treatment of colon cancer (2007-2008). The outcomes evaluated using MedPAR compared the total length of hospital stay (LOS) and the costs associated with both techniques. Because MedPAR is a claims data set that does not provide outcomes at a patient level, a single-institution retrospective case-control study was conducted in which each stent placement patient was matched with two colostomy patients during the same period. Outcome measures (institutional data) were used to compare rates of treatment success, postprocedure LOS, and reinterventions between the two cohorts. The MedPAR data evaluated 778 stent placements and 5,868 colostomy hospitalizations. There were no differences in gender, age distribution, or comorbidity between the two groups. Compared with colostomy, the median LOS (8 vs. 12 days; p<0.0001) and the median cost ($15,071 vs. $24,695; p<0.001) per claim were significantly less for stent placement. Stent placement was more commonly performed at urban versus rural hospitals (84% vs. 16%; p<0.0001), teaching versus nonteaching hospitals (56% vs. 44%; p=0.0058) and larger versus smaller institutions (mean bed capacity, 331 vs. 227; p<0.0001). The institution data included 12 patients who underwent stent placement and 24 who underwent colostomy. Although both methods were technically successful, the median postprocedure LOS (2.17 vs. 10.58 days; p=0.0004) and the rate of readmissions for complications (0% vs. 25%; p=0.01) were significantly lower for stent placement. Although the technical and clinical outcomes for colostomy and stent placement appear comparable, stent placement is less costly and associated with shorter LOS and fewer complications. Dissemination of stent placement beyond large teaching hospitals located in urban areas as a treatment for MCO is important given its implications for patient care and resource use.

Malignant biliary disease: percutaneous interventions.

PubMed

Morgan, R A; Adam, A N

2001-09-01

Interventional radiologists have an important role in the management of patients with malignant biliary obstruction. This article describes the techniques for percutaneous biliary drainage, insertion of biliary endoprostheses, and the management of occluded biliary endoprostheses. Most procedures are performed by using fluoroscopic guidance alone. Ultrasound is also a useful modality for guiding biliary drainage, particularly drainage of the left biliary ducts. Patients should be treated by internal drainage if possible. Metallic endoprostheses can be inserted at the time of the initial biliary drainage procedure. Plastic tubes should be inserted a few days after biliary drainage because of their relatively large size compared with metallic stents. Occluded plastic stents should be replaced. Blocked metallic stents should be treated either by placement of additional overlapping metallic stents or by placement of plastic stents within the metallic stent lumen. Copyright 2001 by W.B. Saunders Company

[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.

Double Kissing Crush Versus Provisional Stenting for Left Main Distal Bifurcation Lesions: DKCRUSH-V Randomized Trial.

PubMed

Chen, Shao-Liang; Zhang, Jue-Jie; Han, Yaling; Kan, Jing; Chen, Lianglong; Qiu, Chunguang; Jiang, Tiemin; Tao, Ling; Zeng, Hesong; Li, Li; Xia, Yong; Gao, Chuanyu; Santoso, Teguh; Paiboon, Chootopol; Wang, Yan; Kwan, Tak W; Ye, Fei; Tian, Nailiang; Liu, Zhizhong; Lin, Song; Lu, Chengzhi; Wen, Shangyu; Hong, Lang; Zhang, Qi; Sheiban, Imad; Xu, Yawei; Wang, Lefeng; Rab, Tanveer S; Li, Zhanquan; Cheng, Guanchang; Cui, Lianqun; Leon, Martin B; Stone, Gregg W

2017-11-28

Provisional stenting (PS) is the most common technique used to treat distal left main (LM) bifurcation lesions in patients with unprotected LM coronary artery disease undergoing percutaneous coronary intervention. The double kissing (DK) crush planned 2-stent technique has been shown to improve clinical outcomes in non-LM bifurcations compared with PS, and in LM bifurcations compared with culotte stenting, but has never been compared with PS in LM bifurcation lesions. The authors sought to determine whether a planned DK crush 2-stent technique is superior to PS for patients with true distal LM bifurcation lesions. The authors randomized 482 patients from 26 centers in 5 countries with true distal LM bifurcation lesions (Medina 1,1,1 or 0,1,1) to PS (n = 242) or DK crush stenting (n = 240). The primary endpoint was the 1-year composite rate of target lesion failure (TLF): cardiac death, target vessel myocardial infarction, or clinically driven target lesion revascularization. Routine 13-month angiographic follow-up was scheduled after ascertainment of the primary endpoint. TLF within 1 year occurred in 26 patients (10.7%) assigned to PS, and in 12 patients (5.0%) assigned to DK crush (hazard ratio: 0.42; 95% confidence interval: 0.21 to 0.85; p = 0.02). Compared with PS, DK crush also resulted in lower rates of target vessel myocardial infarction I (2.9% vs. 0.4%; p = 0.03) and definite or probable stent thrombosis (3.3% vs. 0.4%; p = 0.02). Clinically driven target lesion revascularization (7.9% vs. 3.8%; p = 0.06) and angiographic restenosis within the LM complex (14.6% vs. 7.1%; p = 0.10) also tended to be less frequent with DK crush compared with PS. There was no significant difference in cardiac death between the groups. In the present multicenter randomized trial, percutaneous coronary intervention of true distal LM bifurcation lesions using a planned DK crush 2-stent strategy resulted in a lower rate of TLF at 1 year than a PS strategy. (Double Kissing and Double Crush Versus Provisional T Stenting Technique for the Treatment of Unprotected Distal Left Main True Bifurcation Lesions: A Randomized, International, Multi-Center Clinical Trial [DKCRUSH-V]; ChiCTR-TRC-11001213). Copyright © 2017 American College of Cardiology Foundation. All rights reserved.

The Influence of a Metal Stent on the Distribution of Thermal Energy during Irreversible Electroporation

PubMed Central

van den Bos, Willemien; Neal, Robert E.; van Lienden, Krijn P.; Besselink, Marc G. H.; van Gemert, Martin J. C.; van der Geld, Cees W. M.; Meijerink, Martijn R.; Klaessens, John H.; Verdaasdonk, Rudolf M.

2016-01-01

Purpose Irreversible electroporation (IRE) uses short duration, high-voltage electrical pulses to induce cell death via nanoscale defects resulting from altered transmembrane potential. The technique is gaining interest for ablations in unresectable pancreatic and hepatobiliary cancer. Metal stents are often used for palliative biliary drainage in these patients, but are currently seen as an absolute contraindication for IRE due to the perceived risk of direct heating of the metal and its surroundings. This study investigates the thermal and tissue viability changes due to a metal stent during IRE. Methods IRE was performed in a homogeneous tissue model (polyacrylamide gel), without and with a metal stent placed perpendicular and parallel to the electrodes, delivering 90 and 270 pulses (15–35 A, 90 μsec, 1.5 cm active tip exposure, 1.5 cm interelectrode distance, 1000–1500 V/cm, 90 pulses/min), and in-vivo in a porcine liver (4 ablations). Temperature changes were measured with an infrared thermal camera and with fiber-optic probes. Tissue viability after in-vivo IRE was investigated macroscopically using 5-triphenyltetrazolium chloride (TTC) vitality staining. Results In the gel, direct stent-heating was not observed. Contrarily, the presence of a stent between the electrodes caused a higher increase in median temperature near the electrodes (23.2 vs 13.3°C [90 pulses]; p = 0.021, and 33.1 vs 24.8°C [270 pulses]; p = 0.242). In-vivo, no temperature difference was observed for ablations with and without a stent. Tissue examination showed white coagulation 1mm around the electrodes only. A rim of vital tissue remained around the stent, whereas ablation without stent resulted in complete tissue avitality. Conclusion IRE in the vicinity of a metal stent does not cause notable direct heating of the metal, but results in higher temperatures around the electrodes and remnant viable tissue. Future studies should determine for which clinical indications IRE in the presence of metal stents is safe and effective. PMID:26844550

Overlapping bio-absorbable scaffolds: Aim for D2D technique?

PubMed

Khan, Asaad A; Dangas, George D

2018-06-01

The results of overlapping metallic stents have been concerning but this practice is often unavoidable in the setting of long or tortuous lesions, diameter discrepancy of proximal and distal vessel, and for residual dissections. Theoretically, bio-absorbable scaffolds may carry an advantage over metallic stents due to the progressive resorption of the scaffold theoretically rendering the overlap a non-issue; this has not been clinically evident. Since stent/scaffold overlap cannot be entirely avoided, improved stent delivery/deployment and scaffold design modification may reduce complications in this complex patient subset. © 2018 Wiley Periodicals, Inc.

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.

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.

Retrievable Stent-Assisted Coiling Technique Using a Solitaire Stent: Treatment of Pancreaticoduodenal Artery Aneurysm Associated With Celiac Artery Occlusion.

PubMed

Sanal, Bekir; Nas, Omer Fatih; Hacikurt, Kadir; Hakyemez, Bahattin; Erdogan, Cuneyt

2016-02-01

True aneurysm of pancreaticoduodenal arcade (PDA) is usually accompanied by stenosis or occlusion of celiac trunk (CeT). The up-to-date and first choice treatment modality of PDA aneurysm is the endovascular approach in nearly all cases except few selected ones necessitating surgery. The main approach in endovascular treatment is embolization of the aneurysm by preserving the parent artery. A case with concomitant CeT occlusion and PDA aneurysm was treated with coil embolization by preserving inferior pancreaticoduodenal artery with retrievable Solitaire(®) stent. In our knowledge, this is the first case with PDA aneurysm treated with this technique. © The Author(s) 2016.

The use of cold sprayed alloys for metallic stents

NASA Astrophysics Data System (ADS)

AL-Mangour, Bandar

With the invention of the coronary stent, which is a wire metal mesh tube designed to keep the arteries open in the treatment of heart diseases, promising clinical outcomes were generated. However, the long term successes of stents have been delayed by significant in-stent restenosis (blockages) and stent fracture. In this research work, it has been proposed to use Cold Gas Dynamic Spraying (CGDS) coating material as an alternative choice to manufacture metallic stent. In CGDS, fine particles are accelerated to a high velocity and undergo solid-state plastic deformation upon impact on the substrate, which leads to particle-particle bonding. The feature of CGDS distinct from other thermal spray techniques is that the processing gas temperature is below the melting point of the feedstock. Therefore, unwanted effects of high temperatures, such as oxidation, grain growth and thermal stresses, are absent. In response to the fact that the majority of stents are made from stainless steel (316L) or Co-Cr alloy (L605), this study specifically addresses the development and characterization of 316L and 316L mixed with L605 coatings produced by the CGDS process. Scanning electron microscopy and electron backscatter diffraction were used to investigate the microstructural changes of these coatings before and after annealing. The effect of gas type on the microstructure of 316L coatings and the role of post-heat treatment in the microstructure and properties are also studied. Of particular interest are grain refinement, heat treatment, mechanical properties and corrosion behavior of the cold sprayed material.

Transhepatic metallic stenting for hepaticojejunostomy stricture following laparoscopic cholecystectomy biliary injury: A case of successful 20 years follow-up.

PubMed

Donatelli, Gianfranco; Mutter, Didier; Dhumane, Parag; Callari, Cosimo; Marescaux, Jacques

2012-07-01

Laparoscopic cholecystectomy is still associated with a considerable rate of biliary injuries and related strictures. Advances in interventional endoscopy and percutaneous techniques have made stenting a preferred treatment modality for the management of these strictures. We report successful 20 years of follow-up of a case of trans-hepatic metallic stenting (2 Gianturco(®) prostheses, 5 cm long, 2 cm in diameter) done for stenosed hepatico-jejunostomy anastomosis after laparoscopic CBD injury. Percutaneous transhepatic stenting and long-term placement of metallic stents need to be re-evaluated as a minimally invasive definitive treatment option for benign biliary strictures in patients with altered anatomy such as hepatico-jejunostomy or in whom re-operation involves high risk.

Materials and Manufacturing Technologies Available for Production of a Pediatric Bioabsorbable Stent

PubMed Central

Alexy, Ryan D.; Levi, Daniel S.

2013-01-01

Transcatheter treatment of children with congenital heart disease such as coarctation of the aorta and pulmonary artery stenosis currently involves the use of metal stents. While these provide good short term results, there are long term complications with their use. Children outgrow metal stents, obligating them to future transcatheter dilations and eventual surgical removal. A bioabsorbable stent, or a stent that goes away with time, would solve this problem. Bioabsorbable stents are being developed for use in coronary arteries, however these are too small for use in pediatric congenital heart disease. A bioabsorbable stent for use in pediatric congenital heart disease needs to be low profile, expandable to a diameter 8 mm, provide sufficient radial strength, and absorb quickly enough to allow vessel growth. Development of absorbable coronary stents has led to a great understanding of the available production techniques and materials such as bioabsorbable polymers and biocorrodable metals. Children with congenital heart disease will hopefully soon benefit from the current generation of bioabsorbable and biocorrodable materials and devices. PMID:24089660

Tracheobronchial Polyflex stents for the management of benign refractory hypopharyngeal strictures.

PubMed

Silva, Rui Almeida; Mesquita, Nuno; Nunes, Pedro Pimentel; Cardoso, Elisabete; Pinto, Ricardo Marcos; Dias, Luís Moreira

2012-02-14

To describe a modified technique for placement of a tracheobronchial self-expanding plastic stent (SEPS) in patients with benign refractory hypopharyngeal strictures in order to improve dysphagia and allow stricture remodeling. A case series of four consecutive patients with complex hypopharyngeal strictures after combined therapy for laryngeal cancer, previously submitted to multiple sessions of dilation without lasting improvement, is presented. All patients underwent placement of a small diameter and unflared tracheobronchial SEPS. Main outcome measurements were improvement of dysphagia and avoiding of repeated dilation. The modified introducer system allowed an easy and technically successful deployment of the tracheobronchial Polyflex stent through the stricture. All four patients developed complications related to stent placement. Two patients had stent migration (one proximal and one distal), two patients developed phanryngocutaneous fistulas and all patients with stents in situ for more than 8 wk had hyperplastic tissue growth at the upper end of the stent. Stricture recurrence was observed at 4 wk follow-up after stent removal in all patients. Although technically feasible, placement of a tracheobronchial SEPS is associated with a high risk of complications. Small diameter stents must be kept in place for longer than 3 mo to allow adequate time for stricture remodeling.

Use of flow-diverting stents as salvage treatment following failed stent-assisted embolization of intracranial aneurysms.

PubMed

Heiferman, Daniel M; Billingsley, Joshua T; Kasliwal, Manish K; Johnson, Andrew K; Keigher, Kiffon M; Frudit, Michel E; Moftakhar, Roham; Lopes, Demetrius K

2016-07-01

Flow-diverting stents, including the Pipeline embolization device (PED) and Silk, have been beneficial in the treatment of aneurysms previously unable to be approached via endovascular techniques. Recurrent aneurysms for which stent-assisted embolization has failed are a therapeutic challenge, given the existing intraluminal construct with continued blood flow into the aneurysm. We report our experience using flow-diverting stents in the repair of 25 aneurysms for which stent-assisted embolization had failed. Nineteen (76%) of these aneurysms at the 12-month follow-up showed improved Raymond class occlusion, with 38% being completely occluded, and all aneurysms demonstrated decreased filling. One patient developed a moderate permanent neurologic deficit. Appropriate stent sizing, proximal and distal construct coverage, and preventing flow diverter deployment between the previously deployed stent struts are important considerations to ensure wall apposition and prevention of endoleak. Flow diverters are shown to be a reasonable option for treating previously stented recurrent cerebral aneurysms. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Role of fully covered self-expandable metal stent for treatment of benign biliary strictures and bile leaks.

PubMed

Pausawasadi, Nonthalee; Soontornmanokul, Tanassanee; Rerknimitr, Rungsun

2012-01-01

Endoscopic therapy by balloon dilation and placement of multiple large-bore plastic stents is the treatment of choice for benign biliary stricture. This approach is effective but it typically requires multiple endoscopic sessions given the short duration of stent patency. The endoscopic approach for treatment of bile leak involves the placement of a stent with or without biliary sphincterotomy. The self-expandable metal stent (SEMS) has traditionally been used for palliation of malignant biliary strictures given the long duration of stent patency owing to their larger stent diameter. Recently, SEMS has been used in a variety of benign biliary strictures and leaks, especially with the design of the covered self-expandable metal stent (CSEMS), which permits endoscopic-mediated stent removal. The use of CSEMS in benign biliary stricture could potentially result in a decrease in endoscopic sessions and it is technically easier when compared to placement of multiple plastic stents. However, complications such as cholecystitis due to blockage of cystic duct, stent migration, infection and pancreatitis have been reported. The potential subsegmental occlusion of contralateral intrahepatic ducts also limits the use of CSEMS in hilar stricture. Certain techniques and improvement of stent design may overcome these challenges in the future. Thus, CSEMS may be appropriate in only highly selected conditions, such as refractory benign biliary stricture, despite multiple plastic stent placement or difficult to treat bile duct stricture from chronic pancreatitis, and should not be used routinely. This review focuses on the use of fully covered self-expandable metal stent for benign biliary strictures and bile leaks.

Unilateral versus bilateral stent insertion for malignant hilar biliary obstruction.

PubMed

Chang, Gang; Xia, Feng-Fei; Li, Hong-Fu; Niu, Su; Xu, Yuan-Shun

2017-11-01

To determine the clinical efficiency and long-term outcomes between unilateral and bilateral stent insertion in patients with malignant hilar biliary obstruction. From August 2012 to February 2016, 63 consecutive patients with malignant hilar biliary obstruction were treated with unilateral or bilateral stent insertion at our center. The bilateral stents were inserted using the side-by-side technique. The clinical efficiency and long-term outcomes were compared between the two groups. Unilateral and bilateral stent insertions were successfully performed in 31 of 33 and 27 of 30 patients, respectively (P = 0.912). No procedure-related complication occurred. Clinical success was achieved in 29 of 31 patients in the unilateral stent group and in 26 of 27 patients in the bilateral stent group (P = 0.637). During the follow-up, re-obstruction of stent occurred in five patients in the unilateral stent group and in three patients in the bilateral stent group (P = 0.58). The significant differences were not observed in the stent patency time (368 vs. 387 days, P = 0.685) and survival (200 vs. 198 days, P = 0.751) between two groups. Based on the univariate and multivariate analyses, the independent risk factors for decreasing the survival time included higher Eastern Cooperative Oncology Group performance status (P = 0.018), higher alanine aminotransferase level (P = 0.009), and absence of anticancer treatment after stent insertion (P = 0.002). Compared to bilateral stent insertion for malignant hilar biliary obstruction, unilateral stent insertion can provide comparable clinical efficiency and long-term outcomes.

Role of Fully Covered Self-Expandable Metal Stent for Treatment of Benign Biliary Strictures and Bile Leaks

PubMed Central

Pausawasadi, Nonthalee; Soontornmanokul, Tanassanee

2012-01-01

Endoscopic therapy by balloon dilation and placement of multiple large-bore plastic stents is the treatment of choice for benign biliary stricture. This approach is effective but it typically requires multiple endoscopic sessions given the short duration of stent patency. The endoscopic approach for treatment of bile leak involves the placement of a stent with or without biliary sphincterotomy. The self-expandable metal stent (SEMS) has traditionally been used for palliation of malignant biliary strictures given the long duration of stent patency owing to their larger stent diameter. Recently, SEMS has been used in a variety of benign biliary strictures and leaks, especially with the design of the covered self-expandable metal stent (CSEMS), which permits endoscopic-mediated stent removal. The use of CSEMS in benign biliary stricture could potentially result in a decrease in endoscopic sessions and it is technically easier when compared to placement of multiple plastic stents. However, complications such as cholecystitis due to blockage of cystic duct, stent migration, infection and pancreatitis have been reported. The potential subsegmental occlusion of contralateral intrahepatic ducts also limits the use of CSEMS in hilar stricture. Certain techniques and improvement of stent design may overcome these challenges in the future. Thus, CSEMS may be appropriate in only highly selected conditions, such as refractory benign biliary stricture, despite multiple plastic stent placement or difficult to treat bile duct stricture from chronic pancreatitis, and should not be used routinely. This review focuses on the use of fully covered self-expandable metal stent for benign biliary strictures and bile leaks. PMID:22563290

[Partial stomach partitioning gastrojejunostomy in the treatment of the malignant gastric outlet obstruction].

PubMed

Abdel-lah-Fernández, Omar; Parreño-Manchado, Felipe Carlos; García-Plaza, Asunción; Álvarez-Delgado, Alberto

2015-01-01

In patients with unresectable gastric cancer and outlet obstruction syndrome, gastric partitioning gastrojejunostomy is an alternative, which could avoid the drawbacks of the standard techniques. Comparison of antroduodenal stent, conventional gastrojejunostomy and gastric partitioning gastrojejunostomy. A retrospective, cross-sectional study was conducted on patients with unresectable distal gastric cancer and gastric outlet obstruction, treated with the three different techniques over the last 12 years, comparing results based on oral tolerance and complications. An analysis was performed on the results using the Student-t test for independent variables. The 22 patients were divided in 3 groups: group I (6 cases) stent, group II (9 cases) conventional gastrojejunostomy, and group III (7 cases) gastric partitioning gastrojejunostomy, respectively. The stent allows a shorter "postoperative" stay and early onset of oral tolerance (P<0.05), however, the gastric partitioning gastrojejunostomy achieve normal diet at 15th day (P<0.05). The mortality rate was higher in the stent group (33%) compared with surgical techniques, with a morbidity of 4/6 (66.7%) in Group I, 6/9 (66.7%) Group II, and 3/7 (42%) Group III. Re-interventions: 2/6 Group I, 3/9 Group II, and 0/7 Group III. The median survival was superior in the gastric partitioning gastrojejunostomy, achieving an overall survival of 6.5 months. The gastric partitioning gastrojejunostomy for treatment of gastric outlet obstruction in unresectable advanced gastric cancer is a safe technique, allowing a more complete diet with lower morbidity and improved survival. Copyright © 2015 Academia Mexicana de Cirugía A.C. Published by Masson Doyma México S.A. All rights reserved.

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

Winklehner, Anna, E-mail: anna.winklehner@usz.ch; Nguyen-Kim, Thi Dan Linh, E-mail: thidanlinh.nguyen@usz.ch; Pfammatter, Thomas, E-mail: thomas.pfammatter@usz.ch

PurposeThis study was designed to evaluate retrospectively the long-term stent-graft patency after renovisceral revascularization with Viabahn Open Revascularization Technique (VORTEC) using computed tomography angiography (CTA) and magnetic resonance angiography (MRA).MethodsIn 34 patients (seven women; mean age 72 ± 8 years) with aortic aneurysm, 63 renovisceral vessels (i.e., 54 renal, nine visceral arteries) were revascularized with VORTEC between 2004 and 2009. All patients obtained a pre- and postinterventional CTA and at least one follow-up CTA or MRA after 6 or more months following intervention (median follow up: 43 months). Detection of bypass occlusion, bypass stenosis, infolding, stent-graft fractures and dislocations, and kidney shrinkage were notedmore » by two readers in consensus. Furthermore, mortality during follow-up was assessed using the medical report.ResultsDuring follow-up, 12.6 % of stent-grafts occluded. Cumulative patency rate was 95.2 ± 2.7 % at 12 months, 87.7 ± 4.4 % at 24 and 36 months, and 84.7 ± 5.2 % at 48, 60, 72, 84, and 89 months, respectively. Overall, 19 % of stent-grafts (12/63) developed bypass stenosis (<50 %, 10 stent-grafts; > 50 %, 2 stent-grafts), in one case stenosis (>70 %) was suspected to be hemodynamically significant. No secondary dislocation, no infolding of renovisceral stent-grafts, and no stent-graft fracture occurred. Kidney shrinkage occurred in nine patients, primarily in patients with an occluded Viabahn (n = 7). Eleven patients (32.3 %) died within the follow-up time period.ConclusionsIn long-term survivors after VORTEC cumulative patency rate remained high, and no stent-graft fractures or secondary dislocations occurred.« less

Endoscopic ultrasound-guided placement of plastic vs. biflanged metal stents for therapy of walled-off necrosis: a retrospective single-center series.

PubMed

Mukai, Shuntaro; Itoi, Takao; Baron, Todd H; Sofuni, Atsushi; Itokawa, Fumihide; Kurihara, Toshio; Tsuchiya, Takayoshi; Ishii, Kentaro; Tsuji, Shujiro; Ikeuchi, Nobuhito; Tanaka, Reina; Umeda, Junko; Tonozuka, Ryosuke; Honjo, Mitsuyoshi; Gotoda, Takuji; Moriyasu, Fuminori; Yasuda, Ichiro

2015-01-01

Recently, a novel fully covered and biflanged metal stent (BFMS)dedicated to the drainage of walled-off necrosis(WON) was developed. The aim of this study was to retrospectively evaluate the safety, efficacy, and cost performance of drainage of WON using the novel BFMS compared with a traditional plastic stent. A total of 70 patients with symptomatic WON were treated under endoscopic ultrasound (EUS) guidance. Initial drainage was conducted using the single gateway technique with placement of one or more plastic stents or a single BFMS.If drainage was unsuccessful,direct endoscopic necrosectomy (DEN)was performed. There were no statistically significant differences in rates of technical success, clinical success,and adverse events between plastics stents and BFMS, despite the size of WON in the BFMS group being significantly larger than that in the plastic stent group (105.6 vs. 77.1 mm; P=0.003).The mean procedure times for the first EUS-guided drainage and for re-intervention were significantly shorter in the BFMS group than in the plastic stent group (28.8±7.1 vs. 42.6±14.2, respectively,for drainage, P<0.001; and 34.9±8.5 vs.41.8±7.6, respectively, for re-intervention, P<0.001). There was no statistically significant difference in the total cost between plastic stent and BFMS use in the treatment of WON ($5352vs. $6274; P=0.25). Plastic stents and BFMS were safe and effective for the treatment of WON. In particular,BFMS placement appeared to be preferable for initial EUS-guided drainage and additional reintervention(e.g. DEN) as it reduced the procedure time. Prospective randomized controlled trials are warranted.

Endoscopic removal of malfunctioning biliary self-expandable metallic stents.

PubMed

Familiari, Pietro; Bulajic, Milutin; Mutignani, Massimiliano; Lee, Linda S; Spera, Gianluca; Spada, Cristiano; Tringali, Andrea; Costamagna, Guido

2005-12-01

Endoscopic removal of malfunctioning self-expandable metallic biliary stents (SEMS) is difficult and not well described. The aim of this study is to review the indications, the techniques, and the results of SEMS removal in a cohort of patients with malfunctioning stents. All patients who underwent an attempt at endoscopic removal of biliary SEMS over a 5-year period were retrospectively identified. The main indications for SEMS removal were the following: distal migration of the stent or impaction to the duodenum, impaction into the bile-duct wall, tissue ingrowth, and inappropriate length of the stent causing occlusion of intrahepatic ducts. SEMS were removed by using foreign-body forceps or polypectomy snares. Endoscopic removal of 39 SEMS (13 uncovered and 26 covered) was attempted in 29 patients (17 men; mean age, 66 years). SEMS extraction was attempted after a mean of 7.5 months (8.75 months standard deviation) post-SEMS insertion. Removal was successful in 20 patients (68.9%) and in 29 SEMS (74.3%). Covered SEMS were effectively removed more frequently than uncovered ones: 24 of 26 (92.3%) and 5 of 13 (38.4%), respectively (p < 0.05). No major complications were recorded. Multivariate analysis showed that the time interval between insertion and removal, SEMS length, stent-mesh design (zigzag vs. interlaced), and indication for removal were not predictive of success at stent removal. Endoscopic removal of biliary SEMS is feasible and safe in more than 70% of cases. Because only 38% of uncovered SEMS were removable, the presence of a stent covering is the only factor predictive of successful stent extraction. The presence of diffuse and severe ingrowth was the main feature limiting SEMS removal.

Full covered self-expandable metal stents for the treatment of anastomotic leak using a silk thread

PubMed Central

Choi, Cheol Woong; Kang, Dae Hwan; Kim, Hyung Wook; Park, Su Bum; Kim, Su Jin; Hwang, Sun Hwi; Lee, Si Hak

2017-01-01

Abstract To evaluate the safety and effectiveness of fixation of the fully covered self-expandable metal stent (SEMS) placement using a silk thread for complete closure of an anastomotic leak. An anastomotic leak is a life-threatening complication after gastrectomy. Although the traditional treatment of choice was surgical re-intervention, an endoscopic SEMS can be used alternatively. During the study period, we retrospectively reviewed consecutive patients who received a modified covered SEMS capable of being fixed using a silk thread (Shim technique) due to an anastomotic leak after gastrectomy to prevent stent migration. Demographic data, stent placement and removal, clinical success, time to resolution, and complications were evaluated. A total of 7 patients underwent fully covered SEMS with a silk thread placement for an anastomotic leak after gastrectomy to treat gastric cancer. The patients’ mean age was 71.3 ± 8.0 years. Man sex was predominant (85.7%). All patients’ American Society of Anesthesiologists (ASA) scores were between I and III. Total gastrectomy was performed in 5 patients (71.4%) and proximal gastrectomy was performed in 2 patients (28.6%). The time between gastrectomy and stent insertion was 22.3 ± 11.1 days. The size of the leaks was 27.1 ± 11.1 mm. Technical success and complete leak closure were achieved in all patients. Stent migration was absent. All stents were removed between 4 and 6 weeks. Delayed esophageal stricture was found in 1 patient (14.2) and successfully resolved after endoscopic balloon dilation. For an anastomotic leak after gastrectomy, fully covered SEMS placement with a silk thread is an effective and safe treatment option without stent migration. The stent extraction time between 4 and 6 weeks was optimal without severe complications. PMID:28723752

Full covered self-expandable metal stents for the treatment of anastomotic leak using a silk thread.

PubMed

Choi, Cheol Woong; Kang, Dae Hwan; Kim, Hyung Wook; Park, Su Bum; Kim, Su Jin; Hwang, Sun Hwi; Lee, Si Hak

2017-07-01

To evaluate the safety and effectiveness of fixation of the fully covered self-expandable metal stent (SEMS) placement using a silk thread for complete closure of an anastomotic leak. An anastomotic leak is a life-threatening complication after gastrectomy. Although the traditional treatment of choice was surgical re-intervention, an endoscopic SEMS can be used alternatively.During the study period, we retrospectively reviewed consecutive patients who received a modified covered SEMS capable of being fixed using a silk thread (Shim technique) due to an anastomotic leak after gastrectomy to prevent stent migration. Demographic data, stent placement and removal, clinical success, time to resolution, and complications were evaluated.A total of 7 patients underwent fully covered SEMS with a silk thread placement for an anastomotic leak after gastrectomy to treat gastric cancer. The patients' mean age was 71.3 ± 8.0 years. Man sex was predominant (85.7%). All patients' American Society of Anesthesiologists (ASA) scores were between I and III. Total gastrectomy was performed in 5 patients (71.4%) and proximal gastrectomy was performed in 2 patients (28.6%). The time between gastrectomy and stent insertion was 22.3 ± 11.1 days. The size of the leaks was 27.1 ± 11.1 mm. Technical success and complete leak closure were achieved in all patients. Stent migration was absent. All stents were removed between 4 and 6 weeks. Delayed esophageal stricture was found in 1 patient (14.2) and successfully resolved after endoscopic balloon dilation.For an anastomotic leak after gastrectomy, fully covered SEMS placement with a silk thread is an effective and safe treatment option without stent migration. The stent extraction time between 4 and 6 weeks was optimal without severe complications.

Time-resolved 3D contrast-enhanced MRA on 3.0T: a non-invasive follow-up technique after stent-assisted coil embolization of the intracranial aneurysm.

PubMed

Choi, Jin Woo; Roh, Hong Gee; Moon, Won-Jin; Kim, Na Ra; Moon, Sung Gyu; Kang, Chung Hwan; Chun, Young Il; Kang, Hyun-Seung

2011-01-01

To evaluate the usefulness of time-resolved contrast enhanced magnetic resonance angiography (4D MRA) after stent-assisted coil embolization by comparing it with time of flight (TOF)-MRA. TOF-MRA and 4D MRA were obtained by 3T MRI in 26 patients treated with stent-assisted coil embolization (Enterprise:Neuroform = 7:19). The qualities of the MRA were rated on a graded scale of 0 to 4. We classified completeness of endovascular treatment into three categories. The degree of quality of visualization of the stented artery was compared between TOF and 4D MRA by the Wilcoxon signed rank test. We used the Mann-Whitney U test for comparing the quality of the visualization of the stented artery according to the stent type in each MRA method. The quality in terms of the visualization of the stented arteries in 4D MRA was significantly superior to that in 3D TOF-MRA, regardless of type of the stent (p < 0.001). The quality of the arteries which were stented with Neuroform was superior to that of the arteries stented with Enterprise in 3D TOF (p < 0.001) and 4D MRA (p = 0.008), respectively. 4D MRA provides a higher quality view of the stented parent arteries when compared with TOF.

Self-expanding Y stents in the treatment of central airway stenosis: a retrospective analysis.

PubMed

Gompelmann, Daniela; Eberhardt, Ralf; Schuhmann, Maren; Heussel, Claus P; Herth, Felix J F

2013-10-01

Central airway obstruction (CAO) is a life-threatening situation. Stent insertion re-establishes patency of the central airways. Self-expanding metallic Y stents have been available since 2005, widening the spectrum of interventional bronchoscopic techniques. Retrospective analysis of all patients treated for CAO with a self-expanding metallic Y stent at the Thoraxklinik Heidelberg between May 2005 and January 2009. A total of 43 patients aged 26-81 had a metallic Y stent inserted endoscopically for the treatment of CAO; 39 of these patients (90.7%) had CAO due to malignant disease, four patients (9.3%) due to benign disease. In all 43 patients, the Y stent was deployed without any complications. A longitudinal follow up was possible in 32 of the 43 patients. The stents remained in situ for an average of 107.1 days (range 1-640 days). In 29 patients with malignant CAO the stenosis was successfully overcome with a Y stent; 11 of these patients died within 6 weeks following stent insertion. On follow up the remaining 18 patients showed immediate improvement of dyspnoea. Eight out of the 18 patients (44.4%) tolerated the stent without problems, two (11.1%) required further stenting, six (33.3%) had complications such as increased secretions, cough, dyspnoea or granulation tissue formation. The stent was removed in one patient (5.6%) due to increased secretions, and in another (5.6%) as the stent was no longer required due to successful tumour-specific therapy. Placement of Y stents in symptomatic CAO allows for quick relief of symptoms. Severe complications are rare. Stent removal is possible after successful treatment of the primary tumour. However, the prognostic indicator for survival is the underlying malignancy.

Neurovascular stent artifacts in 3D-TOF and 3D-PCMRI: Influence of stent design on flow measurement.

PubMed

Bouillot, Pierre; Brina, Olivier; Delattre, Bénédicte M A; Ouared, Rafik; Pellaton, Alain; Yilmaz, Hasan; Machi, Paolo; Lovblad, Karl-Olof; Farhat, Mohamed; Pereira, Vitor Mendes; Vargas, Maria Isabel

2018-06-12

The morphological and hemodynamic evaluations of neurovascular diseases treated with stents would benefit from noninvasive imaging techniques such as 3D time-of-flight MRI (3D-TOF) and 3D phase contrast MRI (3D-PCMRI). For this purpose, a comprehensive evaluation of the stent artifacts and their impact on the flow measurement is critical. The artifacts of a representative sample of neurovascular stents were evaluated in vitro with 3D-TOF and 3D-PCMRI sequences. The dependency of the artifacts with respect to the orientation was analyzed for each stent design as well as the impact on the flow measurement accuracy. Furthermore, the 3D-PCMRI data of four patients carrying intracranial aneurysms treated with flow diverter stents were analyzed as illustrative examples. The stent artifacts were mainly confined to the stent lumen therefore indicating the leading role of shielding effect. The influence of the stent design and its orientation with respect to the transmitting MR coils were highlighted. The artifacts impacted the 3D-PCMRI velocities mainly in the low magnitude domains, which were discarded from the analysis ensuring reliable near-stent velocities. The feasibility of in-stent flow measurements was confirmed in vivo on two patients who showed strong correlation between flow and geometric features. In two other patients, the consistency of out-of-stent velocities was verified qualitatively through intra-aneurysmal streamlines except when susceptibility artifacts occurred. The present results motivate the conception of low inductance or nonconductive stent design. Furthermore, the feasibility of near-stent 3D-PCMRI measurements opens the door to clinical applications like the post-treatment follow-up of stenoses or intracranial aneurysms. © 2018 International Society for Magnetic Resonance in Medicine.

A systematic review and meta-analysis of randomized trials and prospective studies comparing covered and bare self-expandable metal stents for the treatment of malignant obstruction in the digestive tract.

PubMed

Yang, Zhiping; Wu, Qiong; Wang, Fang; Ye, Xiaofei; Qi, Xingshun; Fan, Daiming

2013-01-01

Self-expandable metal stents (SEMS) are widely used for the palliative treatment of malignant gastrointestinal obstruction. Our aim was to evaluate the evidence comparing covered and bare SEMS in the digestive tract using meta-analytical techniques. A literature search was performed using PubMed, Cochrane Library, and Embase databases for comparative studies assessing the two types of stents. The primary outcomes of interest were stent patency and patient survival; second outcomes included technical success, clinical success, tumor ingrowth, tumor overgrowth, and stent migration. A random-effects model was conducted. Pooled analysis was done separately based on the different segments of the digestive tract. Eleven studies (8 randomized controlled trials and 3 prospective cohort studies) including a total of 1376 patients were identified. Covered SEMS were equivalent to bare SEMS in terms of technical success, clinical success, stent patency (gastroduodenal obstruction: HR =0.87, 95% CI 0.53-1.42; colorectal obstruction: HR =0.89, 95% CI 0.18-4.45; biliary obstruction: HR =0.73, 95% CI 0.41-1.32) and survival rates (esophageal obstruction: HR =1.80, 95% CI 0.73-4.44; gastroduodenal obstruction: HR =0.83, 95% CI 0.55-1.26; biliary obstruction: HR =0.99, 95% CI 0.77-1.28), although bare stents were more prone to tumor ingrowth (esophageal obstruction: RR =0.10, 95% CI 0.01-0.77; gastroduodenal obstruction: RR =0.12, 95% CI 0.03-0.55; colorectal obstruction: RR =0.21, 95% CI 0.06-0.70; biliary obstruction: RR =0.21, 95% CI 0.06-0.69), whereas covered stents had the higher risk of stent migration (gastroduodenal obstruction: RR =5.01, 95% CI 1.53-16.43; colorectal obstruction: RR =11.70, 95% CI 2.84-48.27; biliary obstruction: RR =8.11, 95% CI 1.47-44.76) and tumor overgrowth (biliary obstruction: RR =2.03, 95% CI 1.08-3.78). Both covered and bare SEMS are comparable in efficacy for the palliative treatment of malignant obstruction in the digestive tract. Each type of the stents has its own merit and demerit relatively.

Role of metallic stents in benign esophageal stricture

NASA Astrophysics Data System (ADS)

Shim, Chan Sup

2012-10-01

Simple esophageal strictures, which are focal, straight, and large in diameter, usually require 1 - 3 dilation sessions to relieve symptoms. However, complex strictures, which are long, tortuous, or associated with a severely compromised luminal diameter, are usually more difficult to treat with conventional bougie or balloon dilation techniques, and often have high recurrence rates. Although the permanent placement of self-expandable metal stents (SEMS) has been used to manage refractory benign esophageal strictures, this procedure is associated with additional problems, such as stricture from tissue hyperplasia, stent migration, and fistula formation. Thus, several new types of stents have been developed, including temporary SEMS, self-expandable plastic stents (SEPS), and biodegradable stents. The use of these new products has produced varied results. Temporary SEMS that have been used to relieve benign esophageal conditions have caused granulation tissue at both ends of the stent because of contact between the mucosa and the exposed metal components of the stent, thus hindering stent removal. We examined the tissue response to two new types of SEMS, a flange-type and a straighttype, each coated with a silicone membrane on the outside of the metal mesh. These two SEMS were evaluated individually and compared with a conventional control stent in animal experiments. Although the newly designed stents resulted in reduced tissue hyperplasia, and were thus more easily separated from the esophageal tissue, some degree of tissue hyperplasia did occur. We suggest that newly designed DES (drug-eluting stents) may provide an alternative tool to manage refractory benign esophageal stricture.

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.

Use of modified Sandwich-graft technique to preserve hypogastric artery in EVAR treatment of complex aortic aneurysm anatomy.

PubMed

Mosquera Arochena, N; Rodríguez Feijoo, G; Carballo Fernandez, C; Molina Herrero, F; Fernandez Lebrato, R; Barrios Castro, A; Garcia Fernandez, I

2011-10-01

Since the introduction of the first endoprosthetic devices, continuous development in techniques and implants has occurred, such as the introduction of a stent graft with branches designed to preserve antegrade flow in the hypogastric artery, a stent-graft designed to treat extreme neck angulation and iliac tortuosity, as well as "Sandwich" and "Chimney" techniques used to maintain perfusion in branch vessels originating in the region to be treated. This paper describes how the Sandwich-Graft technique was adapted, as described by Lobato et al., employing the Aorfix™ system (Lombard Medical) and the Viabahn™ (W.L.Gore) to preserve hypogastric flow in cases with extreme neck angulation and iliac tortuosity. The study included four patients treated from April 2010 until November 2010 with the modified Sandwich technique. All patients eligible for this approach were considered unfit for open repair and were not suitable for an iliac branch graft (Z-BIS Zenith™ Cook Medical). A bifurcated endograft was implanted with specific, in-situ, branching to the target hypogastric artery and achieved clinical and technical success, in all the patients. After a 11-month follow-up in two cases and a six-month follow-up in the other two, clinical results were successful. All patients were endoleak-free, had patent hypogastric branches and had shrinking or stable aneurysms. The initial experience shows that the Sandwich technique with the Aorfix™ stent-graft demonstrated to be effective in endovascular repair of abdominal aortic aneurysms in patients with aortoiliac anatomy hostile to preserving hypogastric artery patency. This graft allows a broader group of patients to be treated with endovascular repair without potential complications of hypogastric artery occlusion; however, further studies are needed to evaluate long-term results in larger numbers of patients.

Successful Use of Orbital Atherectomy as an Adjunct in Treating Extensively Calcified Mesenteric Artery Lesions.

PubMed

Richard, Michele; Krol, Emilia; Dietzek, Alan

2016-10-01

To describe the use of orbital technique of atherectomy as an adjunct to successful angioplasty and stent placement of the superior mesenteric artery (SMA). The technique is demonstrated in a 68-year-old man with critical SMA stenosis. The SMA was cannulated with 0.014-in wire, but the lesion was highly stenotic and densely calcified and prevented the passage of even the smallest 1.5-mm balloon. Orbital atherectomy was thus performed with a 1.25-mm CSI crown. Balloon angioplasty was then possible with a 4 mm × 2 cm balloon followed by placement of a 7 mm × 22 mm balloon-mounted stent. The use of atherectomy as an adjunct to angioplasty and stenting in extensive, calcified SMA lesions supports the value of this technique to avoid a much larger and morbid open procedure. Published by Elsevier Inc.

Vascular stents with submicrometer-scale surface patterning realized via titanium deep reactive ion etching

NASA Astrophysics Data System (ADS)

Gott, Shannon C.; Jabola, Benjamin A.; Rao, Masaru P.

2015-08-01

Herein, we report progress towards realization of vascular stents that will eventually provide opportunity for evaluating cellular response to rationally-designed, submicrometer-scale surface patterning in physiologically-relevant contexts, i.e. those that provide exposure to the complex multicellular milieu, flow-induced shear, and tissue-device interactions present in vivo. Specifically, using our novel titanium deep reactive ion etching technique (Ti DRIE), we discuss recent advances that have enabled: (a) fabrication of precisely-defined, grating-based surface patterns on planar Ti foils with minimum feature sizes as small as 0.15 μm (b) creation of cylindrical stents from micromachined planar Ti foils; and (c) integration of these processes to produce the first submicrometer-scale surface-patterned Ti stents that are compatible with conventional balloon catheter deployment techniques. We also discuss results from elastoplastic finite element simulations and preliminary mechanical testing of these devices to assess their mechanical performance. These efforts represent key steps towards our long-term goal of developing a new paradigm in stenting, where rationally-designed surface patterning provides a physical means for facilitating healing, and thus, improving outcomes in vascular intervention applications.

Advanced endografting techniques: snorkels, chimneys, periscopes, fenestrations, and branched endografts.

PubMed

Kansagra, Kartik; Kang, Joseph; Taon, Matthew-Czar; Ganguli, Suvranu; Gandhi, Ripal; Vatakencherry, George; Lam, Cuong

2018-04-01

The anatomy of aortic aneurysms from the proximal neck to the access vessels may create technical challenges for endovascular repair. Upwards of 30% of patients with abdominal aortic aneurysms (AAA) have unsuitable proximal neck morphology for endovascular repair. Anatomies considered unsuitable for conventional infrarenal stent grafting include short or absent necks, angulated necks, conical necks, or large necks exceeding size availability for current stent grafts. A number of advanced endovascular techniques and devices have been developed to circumvent these challenges, each with unique advantages and disadvantages. These include snorkeling procedures such as chimneys, periscopes, and sandwich techniques; "homemade" or "back-table" fenestrated endografts as well as manufactured, customized fenestrated endografts; and more recently, physician modified branched devices. Furthermore, new devices in the pipeline under investigation, such as "off-the-shelf" fenestrated stent grafts, branched stent grafts, lower profile devices, and novel sealing designs, have the potential of solving many of the aforementioned problems. The treatment of aortic aneurysms continues to evolve, further expanding the population of patients that can be treated with an endovascular approach. As the technology grows so do the number of challenging aortic anatomies that endovascular specialists take on, further pushing the envelope in the arena of aortic repair.

Treatment of Portosystemic Shunt Myelopathy with a Stent Graft Deployed through a Transjugular Intrahepatic Route

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

Jain, Deepak, E-mail: deepakjain02@yahoo.com; Arora, Ankur, E-mail: aroradrankur@yahoo.com; Deka, Pranjal, E-mail: drpranjaldeka@gmail.com

2013-08-01

A case of surgically created splenorenal shunt complicated with shunt myelopathy was successfully managed by placement of a stent graft within the splenic vein to close the portosystemic shunt and alleviate myelopathy. To our knowledge, this is the first report of a case of shunt myelopathy in a patient with noncirrhotic portal fibrosis without cirrhosis treated by a novel technique wherein a transjugular intrahepatic route was adopted to deploy the stent graft.

Percutaneous Pancreatic Stent Placement for Postoperative Pancreaticojejunostomy Stenosis: A Case Report

PubMed Central

Yang, Seung Koo

2016-01-01

Stenosis of the pancreatico-enteric anastomosis is one of the major complications of pancreaticoduodenectomy (PD). Endoscopic stent placement, has limited success rate as a nonsurgical treatment due to altered gastrointestinal anatomy. Percutaneous treatment is rarely attempted due to the technical difficulty in accessing the pancreatic duct. We reported a case of pancreaticojejunostomy stenosis after PD, in which a pancreatic stent was successfully placed using a rendezvous technique with a dual percutaneous approach. PMID:27587970

Transhepatic metallic stenting for hepaticojejunostomy stricture following laparoscopic cholecystectomy biliary injury: A case of successful 20 years follow-up

PubMed Central

Donatelli, Gianfranco; Mutter, Didier; Dhumane, Parag; Callari, Cosimo; Marescaux, Jacques

2012-01-01

Laparoscopic cholecystectomy is still associated with a considerable rate of biliary injuries and related strictures. Advances in interventional endoscopy and percutaneous techniques have made stenting a preferred treatment modality for the management of these strictures. We report successful 20 years of follow-up of a case of trans-hepatic metallic stenting (2 Gianturco® prostheses, 5 cm long, 2 cm in diameter) done for stenosed hepatico-jejunostomy anastomosis after laparoscopic CBD injury. Percutaneous transhepatic stenting and long-term placement of metallic stents need to be re-evaluated as a minimally invasive definitive treatment option for benign biliary strictures in patients with altered anatomy such as hepatico-jejunostomy or in whom re-operation involves high risk. PMID:22837599

Transjugular Intrahepatic Portosystemic Shunt Flow Reduction with Adjustable Polytetrafluoroethylene-Covered Balloon-Expandable Stents Using the “Sheath Control” Technique

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

Blue, Robert C., E-mail: Robert.c.blue@gmail.com; Lo, Grace C.; Kim, Edward

PurposeA complication of transjugular intrahepatic portosystemic shunts (TIPS) placement is refractory portosystemic encephalopathy (PSE) often requiring TIPS reduction. We report the results of a “sheath control technique” utilizing constraining sheaths during deployment of polytetrafluoroethylene (PTFE)-covered balloon-expandable stents, minimizing stent migration, and providing additional procedural control.MethodsTIPS reduction was performed in 10 consecutive patients for PSE using Atrium iCast covered stents (Atrium Maquet Getinge Group, Germany). Within the indwelling TIPS stent, a 9 mm × 59 mm iCast stent was deployed with 2 cm exposed from the sheath’s distal end and the majority of the stent within the sheath to create the distal hourglass shape. During balloonmore » retraction, the stent was buttressed by the sheath. The proximal portion of the stent was angioplastied to complete the hourglass configuration, and the central portion of the stent was dilated to 5 mm. Demographics, pre- and post-procedure laboratory values, and outcomes were recorded.ResultsTen patients underwent TIPS reduction with 100 % technical success. There was no stent migration during stent deployment. All patients experienced initial improvement of encephalopathy. One patient ultimately required complete TIPS occlusion for refractory PSE, and another developed TIPS occlusion 36 days post-procedure. There was no significant trend toward change in patients’ MELD scores immediately post-procedure or at 30 days (p = 0.46, p = 0.47, respectively).ConclusionTIPS reduction using Atrium iCast PTFE balloon-expandable stents using the “sheath control technique” is safe and effective, and minimizes the risk of stent migration.« less

The sea anchor technique: a novel method to aid in stent-assisted embolization of giant cerebral aneurysms.

PubMed

Edwards, Landon; Kota, Gopi; Morris, Padraig P

2013-11-01

Endovascular navigation past some large or giant intracranial aneurysms for the purpose of stent deployment can be difficult. Some of these lesions have a morphology which compels the operator to navigate through the aneurysm dome in order to gain distal access, a step which requires straightening of the delivery microcatheter before a stent can be deployed. In most patients this can be achieved by simply retracting the microcatheter and reducing the loop within the aneurysm. However, in certain patients the acute angle formed between aneurysm inflow and outflow tracts as well as the dynamics of tension within the microcatheter act together to prevent this from happening. Instead of retracting and straightening across the aneurysm neck, the microcatheter withdraws leaving the intra-aneurysm loop intact. This challenge can thwart attempts at stent placement and subsequent embolization. The authors describe a simple and safe technique to circumvent this problem, a way of stabilizing the distal tip of the microcatheter which they term the 'sea anchor'.

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.

Treatment of long, diffuse, in-stent restenotic lesions with beta radiation using strontium 90 and sequential positioning "pullback" technique: procedural details and clinical outcomes.

PubMed

Crocker, I; Joyal, M; Fox, T; Arsenault, A; Bonan, R

2001-12-01

Long, diffuse, in-stent restenotic lesions have been problematic for many patients, necessitating the need for multiple repeat percutaneous coronary interventions (PCI). The need for repeat PCI has been significantly reduced in patients since the advent of vascular brachytherapy. In-stent restenosis resulting in long lesions (> 30 mm) presents even more of a challenge. The interventional injury length created during PCI is usually greater than 30 mm and the vascular brachytherapy systems available in most hospitals are 30 mm or 40 mm in length. The purpose of this paper is to define "pullback technique" and to report the Montreal Heart Institute (MHI) data to show that the pullback technique using the Novoste system seems to be a safe and effective method for using vascular brachytherapy to treat long, diffuse, in-stent restenotic lesions. We reviewed the database of patients enrolled in the Compassionate Use Registry between August 1999 and July 2000. The data are reported on 23 consecutive patients treated with the pullback technique. The mean lesion length was 49.4 +/- 19.8 mm. Three patients (13%) underwent target vessel revascularization. Angiographic follow-up was obtained in 18 patients (78%). Seven patients (38.8%) showed angiographic restenosis (> 50% luminal re-narrowing). No aneurysms or zones of ectasia were noted. This angiographic and clinical evaluation of the MHI Compassionate Use Registry data show the pullback technique to be safe from both a dosimetric and clinical point of view.

Percutaneous Intraductal Radiofrequency Ablation Combined with Biliary Stent Placement for Nonresectable Malignant Biliary Obstruction Improves Stent Patency but not Survival.

PubMed

Wang, Jianfeng; Zhao, Lizhen; Zhou, Chuanguo; Gao, Kun; Huang, Qiang; Wei, Baojie; Gao, Jun

2016-04-01

Although radiofrequency (RF) ablation has been accepted as a curative treatment modality for solid organ tumors, intraductal RF ablation for malignant biliary obstruction has not been widely described. The aim of this study was to evaluate the feasibility, safety, and efficacy (in terms of stent patency and survival) of intraductal RF ablation combined with biliary stent placement for nonresectable malignant biliary obstruction. A search of the nonresectable malignant extrahepatic biliary obstruction database (179 patients) identified 18 consecutive patients who were treated with biliary intraluminal RF ablation during percutaneous transhepatic cholangiodrainage and inner stent placement (RF ablation group) and 18 patients who underwent inner stent placement without biliary intraluminal RF ablation (control group). The patients were matched for tumor type, location of obstruction, tumor stage, and Child-Pugh class status. Primary endpoints included safety, stent patency time, and survival rates. The secondary endpoint was effectiveness of the technique. The RF ablation and control groups were closely matched in terms of age, diagnosis, presence of metastases, presence of locally advanced tumor, American Society of Anesthesiologists (ASA) grade, and chemotherapy regimen (all P > 0.05). The technical success rate for both groups was 100%. The median time of stent patency in the RF ablation and control groups were 5.8 (2.8-11.5) months and 4.5 (2.4-8.0) months, respectively (Kaplan-Meier analysis: P = 0.03). The median survival times in the RF ablation and control groups were 6.1 (4.8-15.2) months and 5.8 (4.2-16.5) months, with no significant difference according to Kaplan-Meier analysis (P = 0.45). In univariate and multivariate analyses, poorer overall survival was associated with advanced age and presence of metastases (P < 0.05). Intraductal RF ablation combined with biliary stent placement for nonresectable malignant biliary obstruction is safe and feasible and effectively increases stent patency time. However, it does not improve patient survival.

PROTECT: PRoximal balloon Occlusion TogEther with direCt Thrombus aspiration during stent retriever thrombectomy - evaluation of a double embolic protection approach in endovascular stroke treatment.

PubMed

Maegerlein, Christian; Mönch, Sebastian; Boeckh-Behrens, Tobias; Lehm, Manuel; Hedderich, Dennis M; Berndt, Maria Teresa; Wunderlich, Silke; Zimmer, Claus; Kaesmacher, Johannes; Friedrich, Benjamin

2017-12-08

Stent retriever-based mechanical thrombectomy (MT) for emergent large vessel occlusions (ELVO) is often complicated by thrombus fragmentation causing distal embolization and embolization to new vascular territories. Well-established embolic protection approaches include proximal flow arrest and distal aspiration techniques during stent retriever maneuvers. Aiming at the reduction of thrombus fragmentation during MT we evaluated a technical approach combining proximal balloon occlusion together with direct thrombus aspiration during MT: the PROTECT technique. We performed a case-control study comparing the PROTECT technique with sole distal aspiration during MT regarding technical and procedural parameters, n=200 patients with ELVO of either the terminus of the internal carotid artery or the proximal middle artery were included. PROTECT resulted in a shorter procedure time (29 vs 40 min; P=0.002), in a higher rate of successful recanalizations (100% vs 78%; P=0.001) and a higher rate of complete reperfusions (70% vs 39%; P<0.001) compared with sole distal aspiration during MT. The PROTECT technique is a promising new approach to significantly reduce thrombus fragmentation and, hence distal embolization during MT. This safe and efficient technique needs to be validated in larger trials to confirm our results. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Preoperative biliary drainage using a fully covered self-expandable metallic stent for pancreatic head cancer: A prospective feasibility study.

PubMed

Togawa, Osamu; Isayama, Hiroyuki; Kawakami, Hiroshi; Nakai, Yousuke; Mohri, Dai; Hamada, Tsuyoshi; Kogure, Hirofumi; Kawakubo, Kazumichi; Sakamoto, Naoya; Koike, Kazuhiko; Kita, Hiroto

2018-01-01

The role of endoscopic preoperative biliary drainage (PBD) for pancreatic head cancer is controversial because of the high incidence of stent occlusion before surgery. This study was performed to evaluate the feasibility and safety of PBD using a fully covered self-expandable metallic stent (FCSEMS). This multicenter prospective study involved 26 patients treated for pancreatic head cancer with distal bile duct obstruction from April 2011 to March 2013. An FCSEMS was endoscopically placed in 24 patients. Among these, 7 patients were diagnosed with unresectable cancer, and 17 underwent surgery at a median of 18 days after FCSEMS placement. The main outcome measure was preoperative and postoperative adverse events. Two adverse events (cholecystitis and insufficient resolution of jaundice) occurred between FCSEMS placement and surgery (12%). Postoperative adverse events occurred in eight patients (47%). The cumulative incidence of stent-related adverse events 4 and 8 weeks after FCSEMS placement among the 24 patients who underwent this procedure were 19%. PBD using an FCSEMS is feasible in patients with resectable pancreatic head cancer. Placement of an FCSEMS can be an alternative PBD technique when surgery without delay is impossible. A larger randomized controlled trial is warranted.

Computational fluid dynamics evaluation of the cross-limb stent graft configuration for endovascular aneurysm repair.

PubMed

Shek, Tina L T; Tse, Leonard W; Nabovati, Aydin; Amon, Cristina H

2012-12-01

The technique of crossing the limbs of bifurcated modular stent grafts for endovascular aneurysm repair (EVAR) is often employed in the face of splayed aortic bifurcations to facilitate cannulation and prevent device kinking. However, little has been reported about the implications of cross-limb EVAR, especially in comparison to conventional EVAR. Previous computational fluid dynamics studies of conventional EVAR grafts have mostly utilized simplified planar stent graft geometries. We herein examined the differences between conventional and cross-limb EVAR by comparing their hemodynamic flow fields (i.e., in the "direct" and "cross" configurations, respectively). We also added a "planar" configuration, which is commonly found in the literature, to identify how well this configuration compares to out-of-plane stent graft configurations from a hemodynamic perspective. A representative patient's cross-limb stent graft geometry was segmented using computed tomography imaging in Mimics software. The cross-limb graft geometry was used to build its direct and planar counterparts in SolidWorks. Physiologic velocity and mass flow boundary conditions and blood properties were implemented for steady-state and pulsatile transient simulations in ANSYS CFX. Displacement forces, wall shear stress (WSS), and oscillatory shear index (OSI) were all comparable between the direct and cross configurations, whereas the planar geometry yielded very different predictions of hemodynamics compared to the out-of-plane stent graft configurations, particularly for displacement forces. This single-patient study suggests that the short-term hemodynamics involved in crossing the limbs is as safe as conventional EVAR. Higher helicity and improved WSS distribution of the cross-limb configuration suggest improved flow-related thrombosis resistance in the short term. However, there may be long-term fatigue implications to stent graft use in the cross configuration when compared to the direct configuration.

Stent-assisted coiling of intracranial aneurysms using LEO stents: long-term follow-up in 153 patients.

PubMed

Sedat, Jacques; Chau, Yves; Gaudart, Jean; Sachet, Marina; Beuil, Stephanie; Lonjon, Michel

2018-02-01

Coiling associated with placement of a self-expandable intracranial stent has improved the treatment of intracranial wide-necked aneurysms. Little is known, however, about the durability of this treatment. The purpose of this report is to present our experience with the LEO stent and to evaluate the complications, effectiveness, and long-term results of this technique. We analyzed the records of 155 intracranial unruptured aneurysms that were treated by stent-assisted coiling with a LEO stent between 2008 and 2012. Procedural, early post-procedural, and delayed complications were recorded. Clinical and angiographic follow-up of patients was conducted over a period of at least 36 months. No procedural mortality was observed. One-month morbidity was observed in 14 out of 153 patients (9,15%). One hundred thirty-eight patients (with 140 aneurysms) had clinical and angiographic follow-up for more than 36 months. No aneurysm rupture was observed during follow-up. Four patients presented an intra-stent stenosis at 8 months, and 6 patients who had an early recurrence were retreated. Final results showed 85% complete occlusion, 13% neck remnants, and 2% stable incomplete occlusion. Stent-assisted coiling with the LEO stent is a safe and effective treatment for unruptured intracranial aneurysms. The long-term clinical outcomes with the LEO stent are excellent with a high rate of complete occlusion that is stable over time.

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.

BIODEGRADABLE BILIARY STENTS: A NEW APPROACH FOR THE MANAGEMENT OF HEPATICOJEJUNOSTOMY STRICTURES FOLLOWING BILE DUCT INJURY. PROSPECTIVE STUDY.

PubMed

Giménez, Mariano E; Palermo, Mariano; Houghton, Eduardo; Acquafresca, Pablo; Finger, Caetano; Verde, Juan M; Cúneo, Jorge Cardoso

2016-01-01

Once a biliary injury has occurred, repair is done by a hepaticojejunostomy. The most common procedure is to perform a dilatation with balloon with a success of 70 %. Success rates range using biodegradable stents is from 85% to 95%. Biodegradable biliary stents should change the treatment of this complication. To investigate the use of biodegradable stents in a group of patients with hepaticojejunonostomy strictures. In a prospective study 16 biodegradable stents were placed in 13 patients with hepaticojejunostomy strictures secondary to bile duct repair of a biliary surgical injury. Average age was 38.7 years (23-67), nine were female and four male. All cases had a percutaneous drainage before at the time of biodegradable stent placement. In one case, temporary haemobilia was present requiring blood transfusion. In another, pain after stent placement required intravenous medication. In the other 11 patients, hospital discharge was the next morning following stent placement. During the patient´s follow-up, none presented symptoms during the first nine months. One patient presented significant alkaline phosphatase elevation and stricture recurrence was confirmed. One case had recurrence of cholangitis 11 months after the stent placement. 84.6% continued asymptomatic with a mean follow-up of 20 months. The placement of biodegradable stents is a safe and feasible technique. Was not observed strictures caused by the stent or its degradation. It could substitute balloon dilation in strictures of hepaticojejunostomy. Uma vez que lesão biliar ocorreu, o reparo é feito por hepaticojejunostomia. O procedimento mais comum é efetuar dilatação com balão com sucesso de 70%. As taxas de sucesso utilizando stents biodegradáveis ​​é de 85% a 95%. Stents biliares biodegradáveis ​​devem mudar o tratamento desta complicação. Investigar o uso de stents biodegradáveis em um grupo de pacientes com estenose hepaticojejunal. Em estudo prospectivo 16 stents biodegradáveis ​​foram colocados em 13 pacientes com estenose de hepaticojejunostomia secundárias usados para reparação do ductos biliares de lesão cirúrgica. A média de idade foi de 38,7 anos (23-67), nove pacientes eram homens e quatro mulheres. Todos os casos tiveram drenagem percutânea antes do momento da colocação de stent biodegradável. Em um caso, haemobilia temporária estava presente com necessidade de transfusão de sangue. Em outro, dor após a colocação do stent necessitou de medicação intravenosa. Nos outros 11 pacientes, alta hospitalar foi na manhã seguinte após o procedimento. Durante o seguimento, nenhum apresentou sintomas durante os primeiros nove meses. Um paciente apresentou significativa elevação da fosfatase alcalina por recidiva da estenose. Um caso teve recorrência de colangite 11 meses após a colocação do stent. Continuaram assintomáticos 84,6% com média de acompanhamento de 20 meses. A colocação de stents biodegradáveis ​​é técnica segura e viável. Não foram observadas restrições causadas pelo stent ou pela sua degradação. Stent pode substituir dilatação com balão na estenose de hepaticojejunostomia.

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

Ahmadi, Ramazan-Ali; Schillinger, Martin; Haumer, Markus

Endarterectomy is currently the preferred treatment for severe carotid stenosis. The technique of eversion endarterectomy allows correction of severe vessel elongation and kinking. The latter is generally believed to be a relative contraindication for endovascular stent placement. We report successful percutaneous transluminal angioplasty and stenting of a left internal carotid artery with high-grade stenosis and severe kinking which was not amenable to endarterectomy because of the distal location of the stenosis. Advanced stent technology with flexible materials makes endovascular treatment of carotid stenosis feasible even in cases of kinking.

Three-dimensional reconstruction of coronary stents in vivo based on motion compensated X-ray angiography

NASA Astrophysics Data System (ADS)

Schäfer, Dirk; Movassaghi, Babak; Grass, Michael; Schoonenberg, Gert; Florent, Raoul; Wink, Onno; Klein, Andrew J. P.; Chen, James Y.; Garcia, Joel; Messenger, John C.; Carroll, John D.

2007-03-01

The complete expansion of the stent during a percutaneous transluminal coronary angioplasty (PTCA) procedure is essential for treatment of a stenotic segment of a coronary artery. Inadequate expansion of the stent is a major predisposing factor to in-stent restenosis and acute thrombosis. Stents are positioned and deployed by fluoroscopic guidance. Although the current generation of stents are made of materials with some degree of radio-opacity to detect their location after deployment, proper stent expansion is hard to asses. In this work, we introduce a new method for the three-dimensional (3D) reconstruction of the coronary stents in-vivo utilizing two-dimensional projection images acquired during rotational angiography (RA). The acquisition protocol consist of a propeller rotation of the X-ray C-arm system of 180°, which ensures sufficient angular coverage for volume reconstruction. The angiographic projections were acquired at 30 frames per second resulting in 180 projections during a 7 second rotational run. The motion of the stent is estimated from the automatically tracked 2D coordinates of the markers on the balloon catheter. This information is used within a motion-compensated reconstruction algorithm. Therefore, projections from different cardiac phases and motion states can be used, resulting in improved signal-to-noise ratio of the stent. Results of 3D reconstructed coronary stents in vivo, with high spatial resolution are presented. The proposed method allows for a comprehensive and unique quantitative 3D assessment of stent expansion that rivals current X-ray and intravascular ultrasound techniques.

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.

Carotid angioplasty and stenting under protection. Techniques, results and limitations.

PubMed

Henry, M; Polydorou, A; Henry, I; Anagnostopoulou, I S; Polydorou, I A; Hugel, M

2006-10-01

A carotid stenosis is responsible for about 30% of strokes occurring. Carotid endarterectomy (CEA) is considered to be the gold standard treatment of a carotid stenosis. Carotid angioplasty and stenting (CAS) is emerging as a new alternative treatment for a carotid artery stenosis, but the risk of neurological complications and brain embolism remains the major drawback to this procedure. Therefore, in order to reduce the risks, we need: 1) good indications, good patient and lesion selection; 2) correct techniques; 3) brain protection devices (cerebral protection devices should be routinely used and are mandatory for any procedure); 4) 3 types of protection devices are available, but filters are the most commonly used (all protection devices have limitations and cannot prevent from all embolic events; however, neurological complications can be reduced by 60%); 5) a good choice of the stent and correct implantation (all stents are not equivalent and have different geometrical effects); 6) pharmacological adjuncts; 7) a good team. Recent studies have shown that CAS has superior short-term outcomes than CEA in high surgical risk patients, but there are enough reported data to conclude that CAS is also not inferior to CEA in low-risk patients. CAS under protection is the standard of care and is maybe becoming the gold standard treatment of a carotid stenosis at least in some subgroups of patients.

Prolonged high-pressure is required for optimal stent deployment as assessed by optical coherence tomography.

PubMed

Cook, Jeffrey R; Mhatre, Ajay; Wang, Fen Wei; Uretsky, Barry F

2014-03-01

Optimizing stent deployment is important for both acute- and long-term outcomes. High-pressure balloon inflation is the standard for coronary stent implantation. However, there is no standardized inflation protocol. We hypothesized that prolonged high-pressure balloon inflation until stabilization of inflation pressure is superior to a rapid inflation/deflation sequence for both stent expansion and strut apposition. A high-pressure rapid inflation/deflation sequence was deployed followed by angiography to assure no residual stenosis. Optical coherence tomography (OCT) was then performed followed by prolonged inflation until balloon pressure was stabilized for 30 sec using the same balloon at the same pressure as the rapid sequence. A second OCT run was then done. Thirteen thousand nine hundred thirteen stent struts were evaluated by OCT in 12 patients undergoing successful stenting. Stent expansion improved with prolonged (206 ± 115 sec) vs. rapid (28 ± 17 sec) inflation for both minimal stent diameter (3.0 ± 0.5 vs. 2.75 ± 0.44 mm, P < 0.0001) and area (7.83 ± 2.45 vs. 6.63 ± 1.85 mm(2) , P = 0.0003). The number of malapposed struts decreased (45 ± 41 vs. 88 ± 75, P = 0.005) as did the maximal malapposed strut distance (0.31 ± 0.2 vs. 0.43 ± 0.2 mm, P = 0.0001). Factors related to strut malapposition after rapid inflation included localized asymmetry in 67%, stent underexpansion in 75%, and stent undersizing in 67%. These data demonstrate that prolonged inflation is superior to a rapid inflation/deflation technique for both stent expansion and strut apposition. We recommend for routine stent deployment a prolonged inflation protocol as described above to optimize stent deployment. Copyright © 2012 Wiley Periodicals, Inc.

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%.

Is early removal of prophylactic ureteric stents beneficial in live donor renal transplantation?

PubMed Central

Indu, K. N.; Lakshminarayana, G.; Anil, M.; Rajesh, R.; George, K.; Ginil, K.; Georgy, M.; Nair, B.; Sudhindran, S.; Appu, T.; Unni, V. N.; Sanjeevan, K. V.

2012-01-01

Prophylactic ureteric stenting has been shown to reduce ureteric leaks and collecting system obstruction following renal transplantation and is in widespread use. However, the optimal time for removal of ureteric stents after renal transplantation remains unclear. Aim of this study was to compare the result of early versus late removal of ureteric stents after kidney transplantation of the laparoscopically retrieved live related donor grafts. Eligible patients were live donor kidney transplant recipients with normal urinary tracts. All recipients underwent extravesical Lich–Gregoire ureteroneocystostomy over 4F/160 cm polyurethane double J stents by a uniform technique. They were randomized on seventh postoperative day for early removal of stents on postoperative day 7 (Group I), or for late removal on postoperative day 28 (Group II). The incidence of urinary tract infections, asymptomatic bacteriuria, and urological complications were compared. Between 2007 and 2009, 130 kidney transplants were performed at one centre of which 100 were enrolled for the study, and 50 each were randomized into the two groups. Donor and recipient age, sex, native renal disease, immunosupression, number of rejection episodes, and antirejection therapy were similar in the two groups. The occurrence of symptomatic urinary tract infection during the follow-up period of 6 months was significantly less in the early stent removal group [5 out of 50 (10%) in Group I, vs 50 out of 15 (30%) in Group II, P=0.02]. Asymptomatic bacteriuria was documented in 2 out of 50 (4%) in Group I and 4 out of 50 (8%) in Group II (P=0.3). There was no statistically significant difference in the rate of ureteric leak, ureteric obstruction, or hematuria in the two groups (P=1.0). We conclude that, in kidney transplant recipients of laparoscopically retrieved live donor grafts, early stent removal at the end of first week reduces the incidence of urinary tract infection without increasing the rate of urine leak or ureteric obstruction. PMID:23162271

The comparation of effects and security of double-J stent retention and ureteroscopy lithotripsy in the treatment of symptomatic ureteral calculi during pregnancy.

PubMed

Tan, Shu-Tao; Chen, Xiaonan; Sun, Ming; Wu, Bin

2018-06-01

To describe the efficacy of double-J stent retention and ureteroscopy lithotripsy, we performed a study to evaluate the management of symptomatic ureteral calculi during pregnancy. From January 2005 and June 2015, 53 pregnant women with symptomatic ureteral calculi were admitted and treated in our hospital. According to the treatment techniques, there were divided into two groups: double-J stent retention group (30 cases) and ureteroscopy lithotripsy group (23 cases). We collected the characteristics and treatment outcome of the patients. Double-J stent retention was performed on 30 patients. And the stents were successfully inserted in 25 patients (83.3%). 4 cases got complication in double-J group (16%). The mean operating time, medical cost and hospitalization time of double-J group were 20.6 min, 1632 yuan and 1.3 days. Ureteroscopy lithotripsy was performed on 23 patients. 20 patients were operated successfully (87.0%). 2 cases got complication in ureteroscopy group (10.0%). The mean operating time, medical cost and hospitalization time of ureteroscopy group were 41.5 min, 2792 yuan and 6.0 days. In summary, both double-J stent retention and ureteroscopy lithotripsy are effective and safe in the managation of ureteral calculi during pregnancy. Copyright © 2018 Elsevier B.V. All rights reserved.

Long-term outcomes of covered self-expandable metal stents for treating benign biliary strictures.

PubMed

Park, Jin-Seok; Lee, Sang Soo; Song, Tae Jun; Park, Do Hyun; Seo, Dong-Wan; Lee, Sung Koo; Han, Seungbong; Kim, Myung-Hwan

2016-05-01

Fully covered, self-expandable metal stents (FCSEMSs) are acceptable tools for treating benign biliary stricture (BBS). However, little is known about the long-term outcomes of this technique. The aim of the present study was to evaluate the procedural and long-term outcomes of FCSEMSs for treating BBSs. A total of 134 consecutive patients (median age 56 years; range 21 - 83) with BBS were retrospectively reviewed. The main outcomes were technical and clinical success, stricture resolution, recurrence, and adverse events. Outcomes were analyzed by reviewing patient medical records. The success rates of FCSEMS placement and removal were 99.3 % and 98.2 %, respectively. Stricture resolution occurred in 103/132 (78.0 %) of the patients (median stent duration, 93 days; range 1 - 489). The associated factors for stricture resolution were longer stent indwelling period (≥ 120 days) and absence of stent migration. Stricture recurrence was seen in 26/103 patients (25.2 %; 95 % confidence interval [CI] 0.17 - 0.34) within a median of 390 days (range 4 - 903 days). Chronic pancreatitis was associated with stricture recurrence (hazard ratio [HR] 2.59, 95 %CI 1.20 - 5.61; P = 0.02). Stent migration occurred in 41/132 patients (31.1 %; 95 %CI 0.23 - 0.39). The FCSEMS with anchoring flaps appeared to protect against stent migration (HR 0.22, 95 %CI 0.08 - 0.63; P < 0.01). FCSEMSs had a high success rate for BBS resolution. Longer indwelling periods and the absence of stent migration might be important factors for stricture resolution. © Georg Thieme Verlag KG Stuttgart · New York.

Advanced Stent Graft Treatment of Venous Stenosis Affecting Hemodialysis Vascular Access: Case Illustrations

PubMed Central

Patel, Darshan; Ray, Charles E.; Lokken, R. Peter; Bui, James T.; Lipnik, Andrew J.; Gaba, Ron C.

2016-01-01

Surgically placed dialysis access is an important component of dialysis replacement therapy. The vast majority of patients undergoing dialysis will have surgically placed accesses at some point in the course of their disease, and for many patients these accesses may represent their definitive renal replacement option. Most, if not all, arteriovenous fistulae and grafts will require interventions at some point in time. Percutaneous angioplasty is the typical first treatment performed for venous stenoses, with stents and stent grafts being reserved for patients in whom angioplasty and surgical options are exhausted. In some salvage situations, stent graft placement may be the only or best option for patients. This article describes, using case illustrations, placement of stent grafts in such patients; a focus will also be made on the techniques utilized in such salvage situations. PMID:27011426

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.

Ascending Aortic Stenting for Acute Supraaortic Stenosis From Graft Collapse.

PubMed

Lader, Joshua M; Smith, Deane E; Staniloae, Cezar; Fallahi, Arzhang; Iqbal, Sohah N; Galloway, Aubrey C; Williams, Mathew R

2018-06-01

A 78-year-old man with remote type-A dissection presented with acute-onset dyspnea. Twenty-two years prior, treatment for his aortic disease required replacement of ascending and arch aneurysms with a polyester graft (Dacron) using the graft inclusion technique. He presented currently in cardiogenic shock. Echocardiography demonstrated new severe hypokinesis of all apical segments. Left-heart catheterization revealed a 120 mm Hg intragraft gradient. Computed tomography arteriography was unrevealing, but intraaortic ultrasound demonstrated critical intragraft stenosis. A balloon expandable stent (Palmaz stent, Cordis, Milpitas, CA) was deployed in the stenotic region with gradient resolution. The patient later underwent aortic root replacement and ascending aneurysm repair (Bio-Bentall technique) and is doing well at 24 months. Copyright © 2018 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

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 induced gastric wall erosion and endoscopic retrieval of nonadjustable gastric band: a new technique.

PubMed

Wilson, Todd D; Miller, Nathan; Brown, Nicholas; Snyder, Brad E; Wilson, Erik B

2013-05-01

In gastrointestinal surgery, specifically in bariatric surgery, there are many types of fixed bands used for restriction and there are a multitude reasons that might eventually be an impetus for the removal of those bands. Bands consisting of Marlex or non silastic materials can be extremely difficult to remove. Intraoperative complications removing fixed bands include the difficulty in locating the band, inability to remove all of the band, and damage to surrounding structures including gastrotomies. Removal of eroded bands endoscopically may pose less risk. Potentially, forced erosion may be an easier modality than surgery, allowing revision without having to deal with the actual band at the time of definitive revision surgery. A retrospective case series developed from a university single institution bariatric practice setting was utilized. Endpoints for the study include success of band removal, complications, length of time the stent was present, and the type of stent. A total of 15 consecutive cases utilizing endoscopic stenting to actively induce fixed gastric band erosion for subsequent endoscopic removal were reviewed. There was an 87 % success rate in complete band removal with partial removal of the remaining bands that resolved the patient's symptoms. A complication rate of 27 % was recorded among the 15 patients, consisting of pain and/or nausea and vomiting. The mean time period of the placement of the stent prior to removal or attempted removal was 16.3 days. Endoscopic forced erosion of fixed gastric bands is feasible, safe, and may offer an advantage over laparoscopic removal. This technique is especially applicable for gastric obstruction from fixed bands, prior to large and definitive revision surgeries, or anticipated hostile anatomy that might preclude an abdominal operation altogether.

Intracorporeal Double-J stent placement during robot-assisted urinary tract reconstruction: technical considerations.

PubMed

Mufarrij, Patrick W; Rajamahanty, Srinivas; Krane, L Spencer; Hemal, Ashok K

2012-09-01

An integral component of many urologic reconstructive surgical procedures is the positioning of a Double-J stent to span the anastomosis. Some surgeons prefer to place a retrograde stent during cystoscopy, either during or after the reconstruction. In this communication, we describe our straightforward and effective approach of performing this critical step intracorporeally using robotic assistance in a variety of upper tract urologic reconstructive procedures. We examined our Institutional Review Board-approved database of robotic surgeries to identify reconstructive operations that included the intracorporeal placement of a Double-J stent since 2008. Our step-by-step method for stent placement during various robotic urologic reconstructions is detailed, including procedures involving the proximal, mid, and distal ureter. With the aid of a bedside assistant-surgeon, we delineate how the console surgeon is able to perform this step of the procedure completely intracorporeally, without the need for repositioning or cystoscopy. Since the inception of our robotic surgical program in 2008, we have used these robotic stent placement techniques in 150 patients. The average time of robotic intracorporeal stent placement across the anastomosis was 3.5 minutes. Three patients did experience proximal stent migration, as documented on postoperative radiographs, but all were treated with conservative measures, because their anastomosis was not affected and severe symptoms did not develop. No patient needed stent replacement, and each stent was subsequently removed ureteroscopically without sequelae. Our robotic intracorporeal Double-J stent placement approach is simple and effective, avoids the need for cystoscopy and fluoroscopy, and can be used in any type of upper urinary tract urologic reconstruction.

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.

To kiss or not to kiss? Impact of final kissing-balloon inflation on early and long-term results of percutaneous coronary intervention for bifurcation lesions.

PubMed

Biondi-Zoccai, Giuseppe; Sheiban, Imad; De Servi, Stefano; Tamburino, Corrado; Sangiorgi, Giuseppe; Romagnoli, Enrico

2014-11-01

Final kissing-balloon inflation is often recommended for percutaneous coronary intervention (PCI) of bifurcation lesions. However, randomized trials focusing on kissing inflation have not confirmed its beneficial impact. We compared outcomes of kissing inflation for PCI of bifurcation lesions, explicitly stratifying results according to stenting strategy. Patients undergoing bifurcation PCI were retrospectively enrolled. Subjects receiving final kissing inflation were compared with those not undergoing kissing inflation, after stratification for a single-stent technique. The primary end point was the long-term rate of major adverse cardiac events (MACE, i.e., death, myocardial infarction, or target lesion revascularization (TLR)). A total of 4314 patients were included: 1176 (27.3 %) treated with a single stent and kissing inflation, 1637 (37.9 %) with a single stent but no kissing, 1072 (24.8 %) with two stents and kissing, and 429 (9.9 %) with two stents but no kissing. At unadjusted analyses kissing was associated with fewer short-term MACE and deaths in the two-stent group, and with fewer long-term MACE, cardiac deaths, and side-branch TLR in the two-stent group (all P < 0.05). Conversely, kissing appeared detrimental after single stenting. However, after multivariable analyses, kissing no longer significantly affected the risk of adverse events, with the exception of the risk of side-branch TLR, which was lower in those receiving two stents and final kissing inflation (hazard ratio = 0.52, 95 % confidence interval 0.30–0.90, P = 0.020). Kissing inflation can be avoided in bifurcation lesions uneventfully treated with single-stent PCI. However, final kissing-balloon inflation appears beneficial in reducing the risk of side-branch repeat revascularization after using a two-stent strategy.

External stenting: A reliable technique to relieve airway obstruction in small children.

PubMed

Ando, Makoto; Nagase, Yuzo; Hasegawa, Hisaya; Takahashi, Yukihiro

2017-05-01

Airway obstruction in children may be caused by conditions such as vascular compression and congenital tracheobronchomalacia. Obstructive pulmonary vascular disease may be a detrimental sequel for patients with congenital heart disease. We evaluate our own original external stenting technique as a treatment option for these patients. Ninety-eight patients underwent external stenting (1997-2015). Cardiovascular anomalies were noted in 82 (83.7%). Nine patients had hypoplastic left heart syndrome and 6 had other types of single-ventricular hearts. The median age at the first operation was 7.2 months (range, 1.0-77.1 months). The mechanisms were tracheobronchomalacia with (n = 46) or without (n = 52) vascular compression. Patients underwent 127 external stentings for 139 obstruction sites (62 trachea, 55 left bronchus, and 22 right bronchus). The stent sizes varied from 12 to 16 mm. There were 14 (8 in the hospital and 6 after discharge) mortality cases. Nine required reoperation for restenosis and 3 required stent removal for infection. The actuarial freedom from mortality and any kind of reoperation was 74.7% ± 4.6% after 2.8 years. The negative pressure threshold to induce airway collapse for congenital malacia (n = 58) improved from -15.9 to -116.0 cmH 2 O. A follow-up computed tomography scan (>2.0 years interval from the operation; n = 23) showed the mean diameter of the stented segment at 88.5% ± 13.7% (bronchus) and 94.5% ± 8.2% (trachea) of the reference. External stenting is a reliable method to relieve airway compression for small children, allowing an age-proportional growth of the airway. Copyright © 2017 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.

Five-year follow-up using a prostate stent as fiducial in image-guided radiotherapy of prostate cancer.

PubMed

Carl, Jesper; Sander, Lotte

2015-06-01

To report results from the five-year follow-up on a previously reported study using image-guided radiotherapy (IGRT) of localized or locally advanced prostate cancer (PC) and a removable prostate stent as fiducial. Patients with local or locally advanced PC were treated using five-field 3D conformal radiotherapy (3DRT). The clinical target volumes (CTV) were treated to 78 Gy in 39 fractions using daily on-line image guidance (IG). Late genito-urinary (GU) and gastro-intestinal (GI) toxicities were scored using the radiotherapy oncology group (RTOG) score and the common toxicity score of adverse events (CTC) score. Urinary symptoms were also scored using the international prostate symptom score (IPSS). Median observation time was 5.4 year. Sixty-two of the 90 patients from the original study cohort were eligible for toxicity assessment. Overall survival, cancer-specific survival and biochemical freedom from failure were 85%, 96% and 80%, respectively at five years after radiotherapy. Late toxicity GU and GI RTOG scores≥2 were 5% and 0%. Comparing pre- and post-radiotherapy IPSS scores indicate that development in urinary symptoms after radiotherapy may be complex. Prostate image-guided radiotherapy using a prostate stent demonstrated survival data comparable with recently published data. GU and GI toxicities at five-year follow-up were low and comparable to the lowest toxicity rates reported. These findings support that the precision of the prostate stent technique is at least as good as other techniques. IPSS revealed a complex development in urinary symptoms after radiotherapy.

Endoscopic surgery and telemedicine in microgravity: developing contingency procedures for exploratory class spaceflight.

PubMed

Jones, J A; Johnston, S; Campbell, M; Miles, B; Billica, R

1999-05-01

The risk of a urinary calculus during an extended duration mission into the reduced gravity environment of space is significant. For medical operations to develop a comprehensive strategy for the spaceflight stone risk, both preventive countermeasures and contingency management (CM) plans must be included. A feasibility study was conducted to demonstrate the potential CM technique of endoscopic ureteral stenting with ultrasound guidance for the possible in-flight urinary calculus contingency. The procedure employed the International Space Station/Human Research Facility ultrasound unit for guide wire and stent localization, a flexible cystoscope for visual guidance, and banded, biocompatible soft ureteral stents to successfully stent porcine ureters bilaterally in zero gravity (0g). The study demonstrated that downlinked endoscopic surgical and ultrasound images obtained in 0g are comparable in quality to 1g images, and therefore are useful for diagnostic clinical utility via telemedicine transmission. In order to be successful, surgical procedures in 0g require excellent positional stability of the operating surgeon, assistant, and patient, relative to one another. The technological development of medical procedures for long-duration spaceflight contingencies may lead to improved terrestrial patient care methodology and subsequently reduced morbidity.

Endoscopic surgery and telemedicine in microgravity: developing contingency procedures for exploratory class spaceflight

NASA Technical Reports Server (NTRS)

Jones, J. A.; Johnston, S.; Campbell, M.; Miles, B.; Billica, R.

1999-01-01

OBJECTIVES: The risk of a urinary calculus during an extended duration mission into the reduced gravity environment of space is significant. For medical operations to develop a comprehensive strategy for the spaceflight stone risk, both preventive countermeasures and contingency management (CM) plans must be included. METHODS: A feasibility study was conducted to demonstrate the potential CM technique of endoscopic ureteral stenting with ultrasound guidance for the possible in-flight urinary calculus contingency. The procedure employed the International Space Station/Human Research Facility ultrasound unit for guide wire and stent localization, a flexible cystoscope for visual guidance, and banded, biocompatible soft ureteral stents to successfully stent porcine ureters bilaterally in zero gravity (0g). RESULTS: The study demonstrated that downlinked endoscopic surgical and ultrasound images obtained in 0g are comparable in quality to 1g images, and therefore are useful for diagnostic clinical utility via telemedicine transmission. CONCLUSIONS: In order to be successful, surgical procedures in 0g require excellent positional stability of the operating surgeon, assistant, and patient, relative to one another. The technological development of medical procedures for long-duration spaceflight contingencies may lead to improved terrestrial patient care methodology and subsequently reduced morbidity.

Protection or nonprotection in carotid stent angioplasty: the influence of interventional techniques on outcome data from the SPACE Trial.

PubMed

Jansen, Olav; Fiehler, Jens; Hartmann, Marius; Brückmann, Hartmut

2009-03-01

The use of protection devices (PDs) and stents with different cell designs in carotid artery stenting (CAS) is a subject of controversy, and no data on their benefit are available from independently controlled multi-center studies. We analyzed data from the prospective randomized SPACE trial, which included 563 patients randomized to CAS and treated per protocol. A total of 145 patients were treated with a PD and 418 without. Of the patients, 436 were treated with an open cell stent and 127 with a closed cell stent. Use of PDs and choice of device was chosen at the individual discretion of the interventionalist. The outcome event (OE) of the analysis (ipsilateral stroke or ipsilateral stroke death within 30 days) was reached in 26/418 patients (6.2%, 95% CI: 4.1 to 9.0%) in the nonprotection [corrected] group and in 12/145 (8.3%, 95% CI: 4.3 to 14.0%) patients in the protection [corrected] group (P=0.40). The OE rate was significantly lower in patients treated with a closed cell stent (5.6% [95% CI: 3.7 to 8.2%]) than in those treated with an open cell stent.(11.0%, 95% CI: 6.2 to 17.8%; P=0.029). Predilatation showed a tendency to but no significant reduction of OE rate. Overall, 49% of all OEs occurred directly periinterventionally, 10% during the navigation procedure and 41% postinterventionally, including 10% of hyperperfusion syndromes. Time point of the event was not influenced by the use of a PD. This secondary analysis of data from the SPACE trial does not support the need for a PD in CAS. Stent design seems to have an impact on the OE rate. Our analysis demonstrates that the choice of the interventional material may have an impact on the periprocedural complication rate in CAS and that the development of more specific stent systems for the treatment of carotid stenosis may reduce the complication rate significantly.

Useful technique for long-term urinary drainage by inlying ureteral stent. Six-year experience.

PubMed

Kearney, G P; Mahoney, E M; Brown, H P

1979-08-01

Endoscopically placed inlying ureteral stents have proved useful in the conservative management of patients with ureteral obstruction, urinary fistula, and malignancy and have obviated the need for operative intervention. In high-risk symptomatic patients with widespread malignancy, internal urinary diversion offers the opportunity for an improved quality of life without the surgical risk or potential morbidity of supravesical diversion. Potential candidates for this simple, safe, and effective technique include: those with postsurgical obstruction and/or fistula, retroperitoneal fibrosis, metastatic carcinoma, congenital ureteropelvic junction obstruction, as well as those with reversible obstruction from lymphoma and carcinoma of the prostate who are undergoing radiotherapy and/or chemotherapy. The focus of this report is on the technique we have found successful in providing us with stents that fit our individual patients. Readily available fabricated graduated ureteral catheter can be cut and shaped to particular measurements unlike prefabricated catheters. Minimal preparation time is demanded, and there is no need for extensive stocking of various catheter sizes.

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.

Bare Metal Stenting for Endovascular Exclusion of Aortic Arch Thrombi

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

Mahnken, Andreas H., E-mail: mahnken@med.uni-marburg.de; Hoffman, Andras; Autschbach, Ruediger

BackgroundAortic thrombi in the ascending aorta or aortic arch are rare but are associated with a relevant risk of major stroke or distal embolization. Although stent grafting is commonly used as a treatment option in the descending aorta, only a few case reports discuss stenting of the aortic arch for the treatment of a thrombus. The use of bare metal stents in this setting has not yet been described.MethodsWe report two cases of ascending and aortic arch thrombus that were treated by covering the thrombus with an uncovered stent. Both procedures were performed under local anesthesia via a femoral approach.more » A femoral cutdown was used in one case, and a total percutaneous insertion was possible in the second case.ResultsBoth procedures were successfully performed without any periprocedural complications. Postoperative recovery was uneventful. In both cases, no late complications or recurrent embolization occurred at midterm follow-up, and control CT angiography at 1 respectively 10 months revealed no stent migration, freely perfused supra-aortic branches, and no thrombus recurrence.ConclusionTreating symptomatic thrombi in the ascending aorta or aortic arch with a bare metal stent is feasible. This technique could constitute a minimally invasive alternative to a surgical intervention or complex endovascular therapy with fenestrated or branched stent grafts.« less

Abdominal Infrarenal Aortic Stenosis Approached Through a Full Transradial Approach: A Case Series.

PubMed

Porto, Italo; Burzotta, Francesco; Aurigemma, Cristina; Gustapane, Massimo; Trani, Carlo

2017-07-01

Six consecutive patients (3 men; mean age, 63 ± 14 years; age range, 38-81 years) with infrarenal abdominal aortic stenosis underwent unilateral or bilateral transradial approach for stenting of the aortic lesion. In 4 cases, isolated aortic stenting was performed through single transradial approach (in 2 cases with precise alignment to the proximal end of previously deployed iliac stents), whereas in the other 2 cases bilateral transradial approach was used for aortic stenting followed by bilateral stenting of the proximal iliac arteries. Either a "bare-on-the-wire" or a "support-catheter" technique was used, according to patient anatomy and technical requirements. The median follow-up was 14.3 months, at which time all patients had relief of symptoms without thromboembolic or bleeding complications. In this performance and safety evaluation, full transradial approach was effective and safe for treating infrarenal aortic stenosis that is isolated or associated with iliac disease.

Compliance Study of Endovascular Stent Grafts Incorporated with Polyester and Polyurethane Graft Materials in both Stented and Unstented Zones

PubMed Central

Guan, Ying; Wang, Lu; Lin, Jing; King, Martin W.

2016-01-01

Compliance mismatch between stent graft and host artery may induce complications and blood flow disorders. However, few studies have been reported on stent graft compliance. This study aims to explore the deformation and compliance of stent graft in stented and unstented zones under three pressure ranges. Compliance of two stent grafts incorporated with polyurethane graft (nitinol-PU) and polyester graft (nitinol-PET) materials respectively were tested; the stents used in the two stent grafts were identical. For the circumferential deformation of the stent grafts under each pressure range, the nitinol-PET stent graft was uniform in both zones. The nitinol-PU stent graft was circumferentially uniform in the stented zone, however, it was nonuniform in the unstented zone. The compliance of the PU graft material was 15 times higher than that of the PET graft. No significant difference in compliance was observed between stented and unstented zones of the nitinol-PET stent graft regardless of the applied pressure range. However, for the nitinol-PU stent graft, compliance of the unstented PU region was approximately twice that of the stented region; thus, compliance along the length of the nitinol-PU stent graft was not constant and different from that of the nitinol-PET stent graft. PMID:28773781

Prospective Multicenter Study on the Challenges Inherent to Using Large Cell-Type Stents for Bilateral Stent-in-Stent Placement in Patients with Inoperable Malignant Hilar Biliary Obstruction.

PubMed

Yang, Min Jae; Kim, Jin Hong; Hwang, Jae Chul; Yoo, Byung Moo; Lee, Sang Hyub; Ryu, Ji Kon; Kim, Yong-Tae; Woo, Sang Myung; Lee, Woo Jin; Jeong, Seok; Lee, Don Haeng

2018-06-22

Although endoscopic bilateral stent-in-stent placement is challenging, many recent studies have reported promising outcomes regarding technical success and endoscopic reintervention. This study aimed to evaluate the technical feasibility of stent-in-stent placement using large cell-type stents in patients with inoperable malignant hilar biliary obstruction. Forty-three patients with inoperable malignant hilar biliary obstruction from four academic centers were prospectively enrolled from March 2013 to June 2015. Bilateral stent-in-stent placement using two large cell-type stents was successfully performed in 88.4% of the patients (38/43). In four of the five cases with technical failure, the delivery sheath of the second stent became caught in the hook-cross-type vertex of the large cell of the first stent, and subsequent attempts to pass a guidewire and stent assembly through the mesh failed. Functional success was achieved in all cases with technical success. Stent occlusion occurred in 63.2% of patients (24/38), with a median patient survival of 300 days. The median stent patency was 198 days. The stent patency rate was 82.9%, 63.1%, and 32.1% at 3, 6, and 12 months, respectively. Endoscopic re-intervention was performed in 14 patients, whereas 10 underwent percutaneous drainage. Large cell-type stents for endoscopic bilateral stent-in-stent placement showed acceptable functional success and stent patency when technically successful. However, the technical difficulty associated with the entanglement of the second stent delivery sheath in the hook-cross-type vertex of the first stent may preclude large cell-type stents from being considered as a dedicated standard tool for stent-in-stent placement.

Experimental Study of Flow Through Carotid Aneurysms

NASA Astrophysics Data System (ADS)

Masoomi, Faezeh; Mejia-Alvarez, Ricardo

2017-11-01

There is evidence that traditional endovascular techniques like coiling are not effective for treatment of wide-neck cerebral aneurysms. Flow Diverter Stents (FDS) have emerged as promising devices for treating complex aneurysms since they enable treatment of aneurysms that were considered untreatable before. Recent studies suggest a number of associated risks with FDS, including in-stent thrombosis, perianeurysmal edema, delayed hemorrhage, and perforator occlusions. Chong et al. simulated hemodynamic behavior using patient-specific data. From their study, it is possible to infer that the standard deviation of energy loss could be a good predictor for intervention success. The aim of this study is to investigate the flow in models of cerebral aneurysms before and after FDS insertion using PIV. These models will be based on actual clinical studies and will be fabricated with advanced additive manufacturing techniques. These data will then be used to explore flow parameters that could inform the likelihood of post-intervention aneurysm rupture, and help determine FDS designs that better suit any particular patient before its procedure.

Flexible ureterorenoscopy and laser lithotripsy in children

PubMed Central

Yeow, When-Chan; Pemberton, Richard; Barker, Andrew

2009-01-01

Background: Flexible ureterorenoscopy (FUR) and laser lithotripsy (LL) are techniques used in the management of upper urinary tract disorders. These techniques, so far established in adults, are now being used in children as well. We report our experience with 26 cases of pediatric upper urinary tract disorders treated using these techniques. Methods: In the period from 1997 to 2006, FUR was performed in 26 children (14 males and 12 females) in the age group of three months to 15 years with a mean age of 8.2 years. Twenty five were stented prior to undergoing FUR and 24 presented with suspected upper tract stones (17 pelvicalyceal and seven midureteric). Two cases showed JJ stent migration post-pyeloplasty. Results: Eight cases involved diagnostic procedures. Six excluded the presence of renal calculi, one had focal medullary sponge kidney, and one had calcified papillae. There were 15 cases of therapeutic FUR. Of these, 12 had LL with only one had incomplete stone fragmentation which subsequently passed spontaneously. Other therapeutic procedures included removal of migrated JJ stents and FUR with the basket removal of a midureteric calculus. Three cases failed ureterorenoscopy due to technical difficulties. The overall success rate was 88.5% for FUR. Conclusion: FUR and LL are valuable minimally invasive techniques for the examination and treatment of pediatric upper urinary tract conditions. Preoperative stenting improves passage of the ureteroscope and with progressive miniaturization of instruments, the lower weight limit will decrease. PMID:20671848

Benchmark for Numerical Models of Stented Coronary Bifurcation Flow.

PubMed

García Carrascal, P; García García, J; Sierra Pallares, J; Castro Ruiz, F; Manuel Martín, F J

2018-09-01

In-stent restenosis ails many patients who have undergone stenting. When the stented artery is a bifurcation, the intervention is particularly critical because of the complex stent geometry involved in these structures. Computational fluid dynamics (CFD) has been shown to be an effective approach when modeling blood flow behavior and understanding the mechanisms that underlie in-stent restenosis. However, these CFD models require validation through experimental data in order to be reliable. It is with this purpose in mind that we performed particle image velocimetry (PIV) measurements of velocity fields within flows through a simplified coronary bifurcation. Although the flow in this simplified bifurcation differs from the actual blood flow, it emulates the main fluid dynamic mechanisms found in hemodynamic flow. Experimental measurements were performed for several stenting techniques in both steady and unsteady flow conditions. The test conditions were strictly controlled, and uncertainty was accurately predicted. The results obtained in this research represent readily accessible, easy to emulate, detailed velocity fields and geometry, and they have been successfully used to validate our numerical model. These data can be used as a benchmark for further development of numerical CFD modeling in terms of comparison of the main flow pattern characteristics.

Endovascular stenting of a chronic ruptured type B thoracic aortic dissection, a second chance: a case report.

PubMed

Arshad, Ali; Khan, Sumaira L; Whitaker, Simon C; Macsweeney, Shane T

2008-02-07

We aim to highlight the need for awareness of late complications of endovascular thoracic aortic stenting and the need for close follow-up of patients treated by this method. We report the first case in the English literature of an endovascular repair of a previously stented, ruptured chronic Stanford type B thoracic aortic dissection re-presenting with a type III endoleak of the original repair. Endovascular thoracic stenting is now a widely accepted technique for the treatment of thoracic aortic dissection and its complications. Long term follow up is necessary to ensure that late complications are identified and treated appropriately. In this case of type III endoleak, although technically challenging, endovascular repair was feasible and effective.

[Application of Silicone Rubber Stents in Intracranial Arterial Microanastomosis for Vessels with Intimal Dissection:A Technical Note].

PubMed

Funatsu, Takayuki; Kawashima, Akitsugu; Mochizuki, Yuichi; Kikuta, Yoshichika; Imanaka, Kousuke; Okada, Yoshikazu

2015-10-01

Intracranial arterial microanastomosis remains an important neurosurgical technique. Intimal dissection of donor or recipient arteries can cause bypass failure. We used a silicone rubber stent while performing arterial microanastomoses, and achieved an excellent postoperative patency rate. In this study, we evaluated the efficacy of the stent in cases of extensive intimal dissection. In 5 cases involving extensive intimal dissection of vessels out of a total of 856 microanastomoses that were performed between November 2000 and August 2014, we placed a silicone rubber stent in the lumen of the recipient artery for donor to recipient suturing. Surgery was performed in 3 cases of cerebrovascular atherosclerotic disease and in 2 cases requiring cerebral revascularization for the treatment of aneurysm recurrence. In one of the 5 cases in which arterial microanastomosis was performed in the spasm period after subarachnoid hemorrhage, a patent anastomosis could not be confirmed. We observed the following advantages of silicone stent use: clear visualization of the orifice created in the vessel, avoidance of suturing or damaging the contralateral side vessel edges, and maintenance of the shape of the anastomosed vessel segment. These advantages made it easier to visualize the intima and to achieve fixation by using tacking sutures.

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

True double bifurcation lesions: new application of the self-expandable Axxess stent and review of literature with dedicated bifurcation devices.

PubMed

Borgia, Francesco; Niglio, Tullio; De Luca, Nicola; Di Serafino, Luigi; Esposito, Giovanni; Trimarco, Bruno; Cirillo, Plinio

2018-04-21

Complex coronary artery bifurcation lesions occurred in hard clinical scenarios, such as acute coronary syndromes, may represent a challenge for interventional cardiologists, with not-defined general consensus on treatment. Even if provisional stenting is the most common option used to restore rapidly the coronary branches flow, improvements in industrial technologies and design of new dedicated bifurcation devices might open new modalities of treatment in these complex cases. The Axxess stent (Biosensors Europe SA, Morges, Switzerland) is a self-expanding biolimus-eluting conical V-shape stent, specifically designed to treat "easily" coronary artery bifurcation lesions, with reported favorable long-term clinical results in stable patients compared to a provisional technique. We report for the first time the feasibility to use this device in a case of "true double coronary bifurcation lesion" occurred in the context of acute coronary syndrome. Moreover, we reviewed studies with bifurcation dedicated devices and available cases of "true double bifurcation lesions", underlying advantages/disadvantages of using one device over the others during acute coronary syndrome. Copyright © 2018 Elsevier Inc. All rights reserved.

An Hybrid 2-Stage Technique to Treat a Post-Traumatic Internal Carotid-Jugular Fistula.

PubMed

Massara, Mafalda; Barillà, David; De Caridi, Giovanni; Serra, Raffaele; Volpe, Alberto; Cutrupi, Andrea; Alberti, Antonino; Volpe, Pietro

2017-01-01

Penetrating wounds of the neck involving the carotid arteries can lead to 2 possible and important late sequelae: pseudoaneurysm formation and arteriovenous fistula (AVF), if an artery and the adjacent jugular vein are simultaneously lacerated. Traumatic AVF of the neck are rare complications and if untreated may cause congestive heart failure, cerebral ischemia, thromboembolism, or even rupture complications. Current treatment options for carotid-jugular AVF include operative repair, detachable balloon, coiling, or stenting. We present a hybrid 2-stage technique to treat an internal carotid-jugular vein fistula in a young woman, based first on carotid stenting to reduce the bleeding and reestablish an adequate cerebral perfusion, followed by stent removal and safe vessels surgical reconstruction through carotid-to-carotid bypass and vein repair. Copyright © 2016 Elsevier Inc. All rights reserved.

A Stent-Retrieving into an Aspiration Catheter with Proximal Balloon (ASAP) Technique: A Technique of Mechanical Thrombectomy.

PubMed

Goto, Shunsaku; Ohshima, Tomotaka; Ishikawa, Kojiro; Yamamoto, Taiki; Shimato, Shinji; Nishizawa, Toshihisa; Kato, Kyozo

2018-01-01

The best technique for the first attempt at mechanical thrombectomy for acute ischemic stroke is a still matter of debate. In this study, we evaluate the efficacy of a stent-retrieving into an aspiration catheter with proximal balloon (ASAP) technique that uses a series of thrombus extraction by withdrawing the stent retriever into the aspiration catheter and continuous aspiration from the aspiration catheter at the first attempt. We performed a retrospective analysis of 42 consecutive patients with acute ischemic stroke caused by occlusions in the anterior circulation who were treated with the ASAP technique at our institution. Preoperative patient characteristic, including age, thrombus location, Alberta Stroke Program Early CT Score, National Institutions of Health Stroke Scale, and time from onset to puncture; postoperative Thrombolysis in Cerebral Infarction score; modified Rankin Scale score after 3 months; time from puncture to recanalization; the number of passes to achieve recanalization; and procedural complications, including intracranial hemorrhage, embolization to new territory, and distal embolization, were assessed. A Thrombolysis in Cerebral Infarction score of 2B or 3 was achieved in 40/42 patients (95.2%). Average time from puncture to the final recanalization was 21.5 minutes. Recanalization was achieved in a single attempt in 31 patients (77.5%). Embolization to new territory was observed in only 2 patients (4.8%); no patient developed distal embolization or intracranial hemorrhage including asymptomatic subarachnoid hemorrhage. Thirty-two patients (76.2%) achieved modified Rankin Scale scores of 0-2 at 3 months postoperatively. Our ASAP technique showed fast recanalization, minimal complications, and good clinical outcomes in this case series. Copyright © 2017 Elsevier Inc. All rights reserved.

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

Ozkan, Ugur, E-mail: radugur@yahoo.com; Oguzkurt, Levent, E-mail: loguzkurt@yahoo.com; Tercan, Fahri, E-mail: ftercan@yahoo.com

The aim of this study was to report our experience in endovascular treatment of total aortoiliac occlusion. Five patients who underwent endovascular recanalization procedures including manual aspiration thrombectomy, balloon angioplasty, and stent placement for total aortoiliac occlusion in a 4-year period were reviewed retrospectively. The mean age of patients was 51 years (range, 43 to 58 years). All patients had abdominal aorta and bilateral common iliac artery occlusion with or without external iliac artery occlusion. All patients either had a contraindication to surgery or refused it. Initial technical success was obtained in four of five (80%) patients. Endovascular techniques weremore » successful in four patients who had good distal runoff and short-segment aortoiliac occlusion, but failed in a patient who had the worst distal runoff and long-segment aortoiliac occlusion. We observed two major complications, one of which was bilateral rupture of the common iliac arteries treated with covered stent placement. Another patient had extension of intra-aortic thrombus into the iliac stent after primary stenting. This was successfully treated with manual aspiration thrombectomy. Aortic and iliac stents remained patent during the follow-up period (median, 18 months; range, 3 to 26 months) in four patients. Primary patency rates at 6, 12, and 24 months were all 80%. In conclusion, endovascular treatment can be an alternative for aortoiliac occlusion in selected patients. Short- to midterm follow-up so far is satisfactory. Removal of intra-aortic thrombus with manual aspiration thrombectomy before balloon angioplasty and/or stenting is possible and a good alternative to thrombolysis.« less

Percutaneous transhepatic biliary stenting in patients with intradiverticular papillae and biliary strictures caused by ampullary carcinoma: A case report

PubMed Central

NIU, HONG-TAO; HUANG, QIANG; ZHAI, REN-YOU

2014-01-01

Endoscopic retrograde cholangiopancreatography with endoscopic sphincterotomy is a well-established procedure for the treatment of bile duct strictures. However, the procedure is difficult to perform in patients with intradiverticular papillae or tumor infiltration of the major papilla. Percutaneous transhepatic biliary stenting (PTBS) is commonly used in the management of malignant biliary stricture. The current study reports two cases of PTBS performed to treat malignant obstructive jaundice caused by ampullary carcinoma complicated with intradiverticular papillae. PTBS is potentially a safe technique for this relatively rare condition. PMID:24944703

Percutaneous transhepatic biliary stenting in patients with intradiverticular papillae and biliary strictures caused by ampullary carcinoma: A case report.

PubMed

Niu, Hong-Tao; Huang, Qiang; Zhai, Ren-You

2014-04-01

Endoscopic retrograde cholangiopancreatography with endoscopic sphincterotomy is a well-established procedure for the treatment of bile duct strictures. However, the procedure is difficult to perform in patients with intradiverticular papillae or tumor infiltration of the major papilla. Percutaneous transhepatic biliary stenting (PTBS) is commonly used in the management of malignant biliary stricture. The current study reports two cases of PTBS performed to treat malignant obstructive jaundice caused by ampullary carcinoma complicated with intradiverticular papillae. PTBS is potentially a safe technique for this relatively rare condition.

Stent sizing strategies in renal artery stenting: the comparison of conventional invasive renal angiography with renal computed tomographic angiography.

PubMed

Kadziela, Jacek; Michalowska, Ilona; Pregowski, Jerzy; Janaszek-Sitkowska, Hanna; Lech, Katarzyna; Kabat, Marek; Staruch, Adam; Januszewicz, Andrzej; Witkowski, Adam

2016-01-01

Randomized trials comparing invasive treatment of renal artery stenosis with standard pharmacotherapy did not show substantial benefit from revascularization. One of the potential reasons for that may be suboptimal procedure technique. To compare renal stent sizing using two modalities: three-dimensional renal computed tomography angiography (CTA) versus conventional angiography. Forty patients (41 renal arteries), aged 65.1 ±8.5 years, who underwent renal artery stenting with preprocedural CTA performed within 6 months, were retrospectively analyzed. In CTA analysis, reference diameter (CTA-D) and lesion length (CTA_LL) were measured and proposed stent diameter and length were recorded. Similarly, angiographic reference diameter (ANGIO_D) and lesion length (ANGIO_LL) as well as proposed stent dimensions were obtained by visual estimation. The median CTA_D was 0.5 mm larger than the median ANGIO_D (p < 0.001). Also, the proposed stent diameter in CTA evaluation was 0.5 mm larger than that in angiography (p < 0.0001). The median CTA_LL was 1 mm longer than the ANGIO_LL (p = NS), with significant correlation of these variables (r = 0.66, p < 0.0001). The median proposed stent length with CTA was equal to that proposed with angiography. The median diameter of the implanted stent was 0.5 mm smaller than that proposed in CTA (p < 0.0005) and identical to that proposed in angiography. The median length of the actual stent was longer than that proposed in angiography (p = 0.0001). Renal CTA has potential advantages as a tool adjunctive to angiography in appropriate stent sizing. Careful evaluation of the available CTA scans may be beneficial and should be considered prior to the planned procedure.

Stent sizing strategies in renal artery stenting: the comparison of conventional invasive renal angiography with renal computed tomographic angiography

PubMed Central

Michalowska, Ilona; Pregowski, Jerzy; Janaszek-Sitkowska, Hanna; Lech, Katarzyna; Kabat, Marek; Staruch, Adam; Januszewicz, Andrzej; Witkowski, Adam

2016-01-01

Introduction Randomized trials comparing invasive treatment of renal artery stenosis with standard pharmacotherapy did not show substantial benefit from revascularization. One of the potential reasons for that may be suboptimal procedure technique. Aim To compare renal stent sizing using two modalities: three-dimensional renal computed tomography angiography (CTA) versus conventional angiography. Material and methods Forty patients (41 renal arteries), aged 65.1 ±8.5 years, who underwent renal artery stenting with preprocedural CTA performed within 6 months, were retrospectively analyzed. In CTA analysis, reference diameter (CTA-D) and lesion length (CTA_LL) were measured and proposed stent diameter and length were recorded. Similarly, angiographic reference diameter (ANGIO_D) and lesion length (ANGIO_LL) as well as proposed stent dimensions were obtained by visual estimation. Results The median CTA_D was 0.5 mm larger than the median ANGIO_D (p < 0.001). Also, the proposed stent diameter in CTA evaluation was 0.5 mm larger than that in angiography (p < 0.0001). The median CTA_LL was 1 mm longer than the ANGIO_LL (p = NS), with significant correlation of these variables (r = 0.66, p < 0.0001). The median proposed stent length with CTA was equal to that proposed with angiography. The median diameter of the implanted stent was 0.5 mm smaller than that proposed in CTA (p < 0.0005) and identical to that proposed in angiography. The median length of the actual stent was longer than that proposed in angiography (p = 0.0001). Conclusions Renal CTA has potential advantages as a tool adjunctive to angiography in appropriate stent sizing. Careful evaluation of the available CTA scans may be beneficial and should be considered prior to the planned procedure. PMID:27279870

Revascularisation versus medical treatment in patients with stable coronary artery disease: network meta-analysis

PubMed Central

Stortecky, Stefan; Stefanini, Giulio G; daCosta, Bruno R; Rutjes, Anne Wilhelmina; Di Nisio, Marcello; Siletta, Maria G; Maione, Ausilia; Alfonso, Fernando; Clemmensen, Peter M; Collet, Jean-Philippe; Cremer, Jochen; Falk, Volkmar; Filippatos, Gerasimos; Hamm, Christian; Head, Stuart; Kappetein, Arie Pieter; Kastrati, Adnan; Knuuti, Juhani; Landmesser, Ulf; Laufer, Günther; Neumann, Franz-Joseph; Richter, Dimitri; Schauerte, Patrick; Sousa Uva, Miguel; Taggart, David P; Torracca, Lucia; Valgimigli, Marco; Wijns, William; Witkowski, Adam; Kolh, Philippe; Juni, Peter

2014-01-01

Objective To investigate whether revascularisation improves prognosis compared with medical treatment among patients with stable coronary artery disease. Design Bayesian network meta-analyses to combine direct within trial comparisons between treatments with indirect evidence from other trials while maintaining randomisation. Eligibility criteria for selecting studies A strategy of initial medical treatment compared with revascularisation by coronary artery bypass grafting or Food and Drug Administration approved techniques for percutaneous revascularization: balloon angioplasty, bare metal stent, early generation paclitaxel eluting stent, sirolimus eluting stent, and zotarolimus eluting (Endeavor) stent, and new generation everolimus eluting stent, and zotarolimus eluting (Resolute) stent among patients with stable coronary artery disease. Data sources Medline and Embase from 1980 to 2013 for randomised trials comparing medical treatment with revascularisation. Main outcome measure All cause mortality. Results 100 trials in 93 553 patients with 262 090 patient years of follow-up were included. Coronary artery bypass grafting was associated with a survival benefit (rate ratio 0.80, 95% credibility interval 0.70 to 0.91) compared with medical treatment. New generation drug eluting stents (everolimus: 0.75, 0.59 to 0.96; zotarolimus (Resolute): 0.65, 0.42 to 1.00) but not balloon angioplasty (0.85, 0.68 to 1.04), bare metal stents (0.92, 0.79 to 1.05), or early generation drug eluting stents (paclitaxel: 0.92, 0.75 to 1.12; sirolimus: 0.91, 0.75 to 1.10; zotarolimus (Endeavor): 0.88, 0.69 to 1.10) were associated with improved survival compared with medical treatment. Coronary artery bypass grafting reduced the risk of myocardial infarction compared with medical treatment (0.79, 0.63 to 0.99), and everolimus eluting stents showed a trend towards a reduced risk of myocardial infarction (0.75, 0.55 to 1.01). The risk of subsequent revascularisation was noticeably reduced by coronary artery bypass grafting (0.16, 0.13 to 0.20) followed by new generation drug eluting stents (zotarolimus (Resolute): 0.26, 0.17 to 0.40; everolimus: 0.27, 0.21 to 0.35), early generation drug eluting stents (zotarolimus (Endeavor): 0.37, 0.28 to 0.50; sirolimus: 0.29, 0.24 to 0.36; paclitaxel: 0.44, 0.35 to 0.54), and bare metal stents (0.69, 0.59 to 0.81) compared with medical treatment. Conclusion Among patients with stable coronary artery disease, coronary artery bypass grafting reduces the risk of death, myocardial infarction, and subsequent revascularisation compared with medical treatment. All stent based coronary revascularisation technologies reduce the need for revascularisation to a variable degree. Our results provide evidence for improved survival with new generation drug eluting stents but no other percutaneous revascularisation technology compared with medical treatment. PMID:24958153

Does antegrade JJ stenting affect the total operative time during laparoscopic pyeloplasty?

PubMed

Bolat, Mustafa Suat; Çınar, Önder; Akdeniz, Ekrem

2017-12-01

We aimed to show the effect of retrograde JJ stenting and intraoperative antegrade JJ stenting techniques on operative time in patients who underwent laparoscopic pyeloplasty. A total of 34 patients were retrospectively investigated (15 male and 19 female) with ureteropelvic junction obstruction. Of the patients stentized under local anesthesia preoperatively, as a part of surgery, 15 were retrogradely stentized at the beginning of the procedure (Group 1), and 19 were antegradely stentized during the procedure (Group 2). A transperitoneal dismembered pyeloplasty technique was performed in all patients. The two groups were retrospectively compared in terms of complications, the mean total operative time, and the mean stenting times. The mean ages of the patients were 31.5±15.5 and 33.2±15.5 years (p=0.09), and the mean body mass indexes were 25.8±5.6 and 26.2.3±8.4 kg/m 2 in Group 1 and Group 2, respectively. The mean total operative times were 128.9±38.9 min and 112.7±21.9 min (p=0.04); the mean stenting times were 12.6±5.4 min and 3.5±2.4 min (p=0.02); and the mean rates of catheterization-to-total surgery times were 0.1 and 0.03 (p=0.01) in Group 1 and 2, respectively. The mean hospital stays and the mean anastomosis times were similar between the two groups (p>0.05). Antegrade JJ stenting during laparoscopic pyeloplasty significantly decreased the total operative time.

Hemodynamic and Anatomic Predictors of Renovisceral Stent-Graft Occlusion Following Chimney Endovascular Repair of Juxtarenal Aortic Aneurysms.

PubMed

Tricarico, Rosamaria; He, Yong; Laquian, Liza; Scali, Salvatore T; Tran-Son-Tay, Roger; Beck, Adam W; Berceli, Scott A

2017-12-01

To identify anatomic and hemodynamic changes associated with impending visceral chimney stent-graft occlusion after endovascular aneurysm repair (EVAR) with the chimney technique (chEVAR). A retrospective evaluation was performed of computed tomography scans from 41 patients who underwent juxtarenal chEVAR from 2008 to 2012 to identify stent-grafts demonstrating conformational changes following initial placement. Six subjects (mean age 74 years; 3 men) were selected for detailed reconstruction and computational hemodynamic analysis; 4 had at least 1 occluded chimney stent-graft. This subset of repairs was systematically analyzed to define the anatomic and hemodynamic impact of these changes and identify signature patterns associated with impending renovisceral stent-graft occlusion. Spatial and temporal analyses of cross-sectional area, centerline angle, intraluminal pressure, and wall shear stress (WSS) were performed within the superior mesenteric and renal artery chimney grafts used for repair. Conformational changes in the chimney stent-grafts and associated perturbations, in both local WSS and pressure, were responsible for the 5 occlusions in the 13 stented branches. Anatomic and hemodynamic signatures leading to occlusion were identified within 1 month postoperatively, with a lumen area <14 mm 2 (p=0.04), systolic pressure gradient >25 Pa/mm (p=0.03), and systolic WSS >45 Pa (p=0.03) associated with future chimney stent-graft occlusion. Chimney stent-grafts at increased risk for occlusion demonstrated anatomic and hemodynamic signatures within 1 month of juxtarenal chEVAR. Analysis of these parameters in the early postoperative period may be useful for identifying and remediating these high-risk stent-grafts.

Use of a balloon-expandable metallic stent for treatment of nasopharyngeal stenosis in dogs and cats: six cases (2005-2007).

PubMed

Berent, Allyson C; Weisse, Chick; Todd, Kimberly; Rondeau, Mark P; Reiter, Alexander M

2008-11-01

To determine outcome associated with use of a balloon-expandable metallic stent for treatment of nasopharyngeal stenosis in dogs and cats. Retrospective case series. 3 dogs and 3 cats. All 6 animals had severe inspiratory stertor at initial examination. Two animals had no orifice present at the stenosis. Nasopharyngeal stenosis was diagnosed and stent size determined by use of computed tomography. A percutaneous transluminal angioplasty balloon premounted with a balloon-expandable metallic stent was placed over a guidewire, advanced through the stenotic lesion under fluoroscopic and rhinoscopic guidance, and dilated to restore patency. All animals had immediate resolution of clinical signs after stent placement. The procedure took a median of 38 minutes (range, 22 to 70 minutes). One animal with a stenosis located far caudally needed the tip of the stent resected because of hairball entrapment and exaggerated swallowing. Both animals without an orifice in the stenosis had tissue in-growth requiring a covered stent. All animals were reexamined 6 to 12 weeks after treatment via rhinoscopy, radiography, computed tomography, or a combination of techniques. All animals lacked signs of discomfort; 5 of 6 were breathing normally 12 to 28 months after the procedure. Transnasal balloon-expandable metallic stent placement may represent a rapid, safe, noninvasive, and effective treatment in animals with nasopharyngeal stenosis. If the stenosis is extremely caudal in the nasopharynx, serial balloon dilatation might be considered prior to stent placement. A covered stent should be considered initially if the stenosis is completely closed.

Stent placement for benign colonic stenosis: case report, review of the literature, and animal pilot data.

PubMed

Geiger, Timothy M; Miedema, Brent W; Tsereteli, Zurab; Sporn, Emanuel; Thaler, Klaus

2008-10-01

Permanent metal stent placement for malignant intestinal obstruction has been proven to be efficient. Temporary stents for benign conditions of the colon and rectum are less studied. This is a case study, review of the literature, and observation from an animal model on placement of stents in the colorectum for benign disease. A 55-year-old man presented with recurrent obstructions from a benign stricture of the distal sigmoid colon. After failed balloon dilations, a polyester coated stent was placed. The purpose of the stent was to improve symptoms and avoid surgery. The stent was expelled after 5 days. We conducted a literature review of stents placed for benign colorectal strictures and an animal study to evaluate stent migration. In the literature, there were 53 reports of uncovered metal stents, four covered metal stents, and six polyester stents. Patency rates were 71%, and migration rate was 43%. Migration occurred earlier with polyester stents (mean=8 days) versus covered (32 days) or uncovered metal stents (112 days). Severe complications were seen in 23% of patients. Four 45-kg pigs underwent rectosigmoid transection with a 21-mm anastomosis and endoscopic placement of a Polyflex stent. Two stents were secured with suture. Stents without fixation were expelled within 24 h of surgery. Stents with fixation were expelled between postoperative days 2 and 14. Stents for the treatment of benign colorectal strictures are safe, with comparable patency rates between stent types. Metal stents can cause severe complications. In a pig model, covered polyester stents tend to migrate early even with fixation. Further investigation needs to focus on new stent designs and/or better fixation.

Solitaire FR stent as an adjunctive tool for pipeline stent deployment in the treatment of giant intracranial aneurysms.

PubMed

Clarençon, Frédéric; Wyse, Gerald; Fanning, Noel; Di Maria, Federico; Gaston, André; Chiras, Jacques; Sourour, Nader

2013-06-01

The use of flow-diverting stents has gained acceptance during the past few years for the treatment of numerous intracranial aneurysms, especially large or giant ones. However, successful catheterization of the distal parent artery in giant intracranial aneurysms with a microcatheter can be extremely challenging. Forming a microcatheter loop in the aneurysm sac can aid distal catheterization. We report the use of a Solitaire FR stent as an adjunctive tool in the successful treatment of 2 giant intracranial unruptured aneurysms with a Pipeline Embolization Device. After having formed a loop inside the aneurysm sac, the microcatheter was anchored distally by a Solitaire FR stent. With the Solitaire FR device opened, the loop in the giant aneurysm sac was completely reduced without loss of the microcatheter position in the distal parent artery. A Pipeline Embolization Device could be delivered in both cases without any difficulty. There were no complications. The technique described results in ideal microcatheter alignment with a secure distal position before deployment of a flow-diverting stent.

Peripheral Atherectomy: Applications and Techniques.

PubMed

Mittleider, Derek; Russell, Erich

2016-06-01

Peripheral atherectomy is a class of procedures that is rapidly increasing in volume. Multiple classes of devices exist, and newer variants are added to the market annually. The devices see wide application for de novo lesions, in-stent restenosis, and adjunctive therapy for drug-coated balloons. The body of evidence supporting atherectomy is less robust than for many other peripheral therapies. The frequency and severity of complications from atherectomy can be significant compared with angioplasty and stenting, and familiarity with preventative and bailout techniques is essential for the interventionalist. Copyright © 2016 Elsevier Inc. All rights reserved.

Long-Term Outcomes of Double-Layered Polytetrafluoroethylene Membrane-Covered Self-Expandable Segmental Metallic Stents (Uventa) in Patients with Chronic Ureteral Obstructions: Is It Really Safe?

PubMed

Kim, Myong; Hong, Bumsik; Park, Hyung Keun

2016-12-01

To evaluate the long-term clinical efficacy and safety of double-layered polytetrafluoroethylene membrane-covered self-expandable segmental metallic stents (Uventa) in patients with chronic ureteral obstruction. In a retrospective study, a total of 50 ureter units (44 patients) with chronic obstructions were included from July 2010 to May 2015. Indications for Uventa placement were primary stenting for malignant ureteral obstruction, failed conventional polymeric Double-J stent (PS), or percutaneous nephrostomy (PCN) technique, with comorbidities or fears limiting PS/PCN changes, or with irritation or pain due to PS/PCN. Patients underwent Uventa stent placement using the antegrade or retrograde approach. There were no immediate procedure-related complications, and all stents were placed in the proper sites. During the median follow-up of 30.9 (interquartile range [IQR], 8.1-49.0) months, the primary (no obstruction and no additional intervention) and overall success (no obstruction and no additional intervention except supplementary Uventa) was 30.0% and 34.0%, respectively. Moreover, 14 of 50 ureter units (28.0%) experienced major complications (≥Clavien-Dindo class IIIb), such as ureteroarterial fistula (three cases, 6.0%), ureteroenteric fistula (three, 6.0%), ureterovaginal fistula (one, 2.0%), ureter perforation (one, 2.0%), uncontrollable bleeding (one, 2.0%), and complete obstruction (five, 10.0%). On univariate analysis, major complications were associated with female (odds ratio [OR] = 6.000), cervical cancer (OR = 4.667), ureteral stricture length (≥6.0 cm, OR = 4.583), and placement duration (≥24.0 months, OR = 20.429; all p < 0.05). In long-term follow-up, the Uventa stent demonstrated poor treatment outcomes with frequent major complications in patients with chronic ureteral obstructions.

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.

A Comparative Study of the efficacy by using different stent-grafts in bell-bottom technique for the treatment of abdominal aortic aneurysm concomitant with iliac artery aneurysm.

PubMed

Wang, Lixin; Liang, Shuangchao; Xu, Xin; Chen, Bin; Jiang, Junhao; Shi, Zhenyu; Tang, Xiao; Zhou, Xiushi; Zhou, Min; Guo, Daqiao; Fu, Weiguo

2018-06-06

Bell-bottom technique (BBT) is one method to preserve the internal iliac artery during EVAR for abdominal aortic aneurysm(AAA) that extend to iliac artery. The data on the efficacy of this technique is still limited. We sought to evaluate the mid-term efficacy of BBT by using different stent-grafts in the treatment of AAA combined with iliac artery aneurysm (IAA). From January 2011 to December 2016, AAA patients with IAA using BBT to preserve the internal iliac artery were retrospectively analyzed in our institution. Patients were followed up at 3, 6 and then every 12 months after surgery. The outcomes among three types of stent-grafts (Zenith, Excluder and Endurant) were compared. BBT related endpoints including type Ib endoleak, IAA sac expansion, distal neck expansion and rupture during follow-up were compared. Other events including perioperative death, any other types of endoleak and corresponding management were also documented. A total of 125 patients with 141 IAAs were identified. Ninety-eight patients (78.4%) with 113 lesions (80.4%) received a median follow-up time of 38 months. The incidence of type Ib endoleak was 22.9%, 8.3%, 11.9% and 14.2% (P=0.19) in Zenith, Excluder, Endurant group and total patients respectively. The incidence of IAA sac enlargement was 17.1%, 5.6%, 7.1% and 9.7% (P=0.20). The incidence of IAA rupture was 8.6%, 0.0%, 0.0% and 2.7%(P=0.03). The incidence of IAA neck enlargement was 34.3%, 13.9%, 16.7% and 21.2%(P=0.07). Totally 14 cases (10.7%) received further treatment for BBT related issues. Although BBT remains a safe and effective treatment option to preserve internal iliac artery during standard EVAR with acceptable complication rates in Asians, different IAA rupture rates were found among three different stent-grafts. Our data first time revealed that the types of stent-grafts have influence on the final clinical outcome. Based on that, iliac extension should be selected appropriately while treating AAA-IAA. Copyright © 2018 Elsevier Inc. All rights reserved.

Percutaneous Injection of Lidocaine Within the Carotid Body Area in Carotid Artery Stenting: An 'Old-New' Technique

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

Mourikis, Dimitrios; Chatoupis, Konstantinos, E-mail: kchatoupis@yahoo.g; Katsenis, Konstantinos

2008-07-15

Severe bradycardia is a common untoward effect during balloon angioplasty when performing carotid artery stenting. Therefore atropine injection even before dilatation and the presence of an anesthesiologist are advocated in all patients. In the surgical literature, injection of a local anesthetic agent into the carotid sinus before carotid endarterectomy was performed in an attempt to ameliorate perioperative hemodynamic instability. This study was undertaken to test the hypothesis that percutaneous infiltration of the carotid sinus with local anesthetic immediately before balloon dilatation reduces bradycardia and ameliorates the need for atropine injection or the presence of an anesthesiologist. Infiltration of the carotidmore » sinus with 5 ml of 1% lidocaine, 3 min before dilatation, was performed in 30 consecutive patients. No one exhibited any significant rhythm change that required atropine injection. The anesthesiologist did not face any hemodynamic instability during the carotid artery stenting procedure.« less

A retrograde y-stenting of the trachea for treatment of mediastinal fistula in an unusual situation

PubMed Central

Hohenforst-Schmidt, Wolfgang; Zarogoulidis, Paul; Steinheimer, Michael; Schneider, Thomas; Benhassen, Naim; Rupprecht, Holger; Freitag, Lutz

2017-01-01

Introduction Stents have been used for quite some time for the treatment of benign and malignant airway stenosis. Silicon stents are preferred for benign situations, whereas metallic self-expanding stents are preferred for malignant comorbidities. Patient and methods In general, stents can be placed in different approach directions, although in pulmonary medicine it is logical to apply only antegrade techniques – until now. A 63-year-old patient, 168 cm height and 53 kg weight on referral, suffered chronical diseases. The patient was diagnosed with a papillary thyroid carcinoma in 1989, which was treated by resection and radiotherapy. In the following years, she developed a stenosis of the esophagus. The decision to try endobronchial stenting was made upon the plan to close that fistula with a pedicled omentum majus replacement through the diaphragmal opening of the esophagus. This surgical plastic needed an abutment and a secured continuous airway replacement above the tracheostoma level. A Freitag stent (FS), 11 cm in length (110–25–40) and an inner diameter of 13 mm, was placed successfully retrograde into the trachea and completely bridged the big fistula. Unfortunately the patient passed away due to pulmonary infections after several weeks. Discussion In this case report, a successful but unusual case of retrograde stent placement of a modified FS is presented. PMID:28579789

Symptomatic stent cast.

PubMed

Keohane, John; Moore, Michael; O'Mahony, Seamus; Crosbie, Orla

2008-02-01

Biliary stent occlusion is a major complication of endoscopic stent insertion and results in repeat procedures. Various theories as to the etiology have been proposed, the most frequently studied is the attachment of gram negative bacteria within the stent. Several studies have shown prolongation of stent patency with antibiotic prophylaxis. We report the case of stent occlusion from a cast of a previously inserted straight biliary stent; a "stent cast" in an 86-year-old woman with obstructive jaundice. This was retrieved with the lithotrypter and she made an uneventful recovery. This is the first reported case of a biliary stent cast.

Prosthetic management of posttraumatic external auditory canal atresia: A rare cause of conductive hearing loss

PubMed Central

Adhershitha, A. R.; Anilkumar, S.; Rajesh, C.; Mohan, Deepak C.

2016-01-01

Acquired external auditory canal (EAC) atresia is an infrequent entity which can originate from a number of different causes including trauma, infection, neoplasia, inflammation, and radiotherapy. Posttraumatic atresias are exceptionally rare, only 10% of atresias are attributed to trauma in most of the series. The management of stenosis of the EAC is challenging as it is associated with residual hearing loss and late recurrence. Traditional stents often occlude the EAC, resulting in a temporary conductive hearing loss. This case report describes the technique of fabrication of a wide-bored acrylic stent which attained additional retention from the folds of the auricle. The customized earmold stent effectively prevented restenosis, while the large bore provided ventilation and improved hearing subjectively during the stenting period. PMID:27746605

Invasive Imaging of Bioresorbable Coronary Scaffolds – A Review

PubMed Central

Ligthart, Jurgen MR; Bruining, Nico; Regar, Evelyn; van Beusekom, Heleen MM

2013-01-01

Various fully bioresorbable stents (BRS) have been recently developed, allowing for temporary scaffolding of the vessel wall. The potentially unique advantage of BRS to temporary scaffold the vessel could reduce the risk of adverse clinical outcomes caused by acute vessel geometry changes, late malapposition, jailed side branches or inflexibility of permanent stents. The design of BRS is, however, not similar for all stents, resulting in differences in degradation and behaviour. To assess the performance of BRS, the effect of degradation and behaviour on the vessel wall should be accurately evaluated. Intracoronary imaging techniques such as intravascular ultrasound (IVUS), optical coherence tomography (OCT) and near-infrared spectroscopy (NIRS) allow for detailed longitudinal evaluation of the stent and the vessel wall and might therefore aid in improving design and behaviour of BRS. PMID:29588747

Application of rotational atherectomy in the drug-eluting stent era

PubMed Central

Chen, Chun-Chi; Hsieh, I-Chang

2013-01-01

Rotational atherectomy (RA) was introduced in the interventional arena in 1988 as a dedicated device for calcified lesions. Due to the complexity of the technique, the development of alternative methods such as the cutting balloon procedure, and the high restenosis rate of subsequent bare metal stenting in long lesions, its use had later declined. However, with the increasing use of drug-eluting stents (DES) and the aggressive treatment of longer lesions, the number of procedure performed with RA has increased significantly again in recent years. In this article, we reviewed the application of RA in DES era. PMID:24133506

Wing-shaped plastic stents vs. self-expandable metal stents for palliative drainage of malignant distal biliary obstruction: a randomized multicenter study.

PubMed

Schmidt, Arthur; Riecken, Bettina; Rische, Susanne; Klinger, Christoph; Jakobs, Ralf; Bechtler, Matthias; Kähler, Georg; Dormann, Arno; Caca, Karel

2015-05-01

Previous studies have shown superior patency rates for self-expandable metal stents (SEMS) compared with plastic stents in patients with malignant biliary obstruction. The aim of this study was to compare stent patency, patient survival, and complication rates between a newly designed, wing-shaped, plastic stent and SEMSs in patients with unresectable, malignant, distal, biliary obstruction. A randomized, multicenter trial was conducted at four tertiary care centers in Germany. A total of 37 patients underwent randomization between March 2010 and January 2013. Patients underwent endoscopic retrograde cholangiography with insertion of either a wing-shaped, plastic stent without lumen or an SEMS.  Stent failure occurred in 10/16 patients (62.5 %) in the winged-stent group vs. 4/18 patients (22.2 %) in the SEMS group (P = 0.034). The median time to stent failure was 51 days (range 2 - 92 days) for the winged stent and 80 days (range 28 - 266 days) for the SEMS (P = 0.002). Early stent failure (< 8 weeks after placement) occurred in 8 patients (50 %) vs. 2 patients (11.1 %), respectively (P = 0.022). After obtaining the results from this interim analysis, the study was discontinued because of safety concerns. The frequency of stent failure was significantly higher in the winged-stent group compared with the SEMS group. A high incidence of early stent failure within 8 weeks was observed in the winged-stent group. Thus, the winged, plastic stent without central lumen may not be appropriate for mid or long term drainage of malignant biliary obstruction. Study registration ClinicalTrials.gov (NCT01063634). © Georg Thieme Verlag KG Stuttgart · New York.

A systematic review of biodegradable biliary stents: promising biocompatibility without stent removal.

PubMed

Siiki, Antti; Sand, Juhani; Laukkarinen, Johanna

2018-05-18

Biodegradable self-expanding stents are an emerging alternative to standard biliary stents as the development of endoscopic insertion devices advances. The aim was to systematically review the existing literature on biodegradable biliary stents. In-vivo studies on the use of biodegradable stents in the biliary duct were systematically reviewed from 1990 to 2017. Despite extensive research on the biocompatibility of stents, the experience so far on their clinical use is limited. A few favorable reports have recently been presented on endoscopically and percutaneously inserted self-expanding biodegradable polydioxanone stents in benign biliary strictures. Another potential indication appears to be postcholecystectomy leak of the cystic duct. The main benefit of biodegradable stents is that stent removal can be avoided. The biocompatibility of the current biodegradable stent materials, most prominently polydioxanone, is well documented. In the few studies currently available, biodegradable stents are reported to be feasible and safe, also in humans. The initial results of the endoscopic use of these stents in benign biliary stricture management and for treating postcholecystectomy bile leaks are promising. Further controlled studies on long-term clinical results and cost-effectiveness are needed.

Airway stent complications: the role of follow-up bronchoscopy as a surveillance method

PubMed Central

Labaki, Wassim; Yu, Diana H.; Salwen, Benjamin; Gilbert, Christopher; Schneider, Andrea L. C.; Ortiz, Ricardo; Feller-Kopman, David; Arias, Sixto; Yarmus, Lonny

2017-01-01

Background Airway stenting has become an integral part of the therapeutic endoscopic management of obstructive benign and malignant central airway diseases. Despite increased use of airway stents and frequent stent-associated complications, no clear guidelines for surveillance and maintenance exist. This study aim is to elucidate predictive factors associated with development of stent complications, as well as an optimal surveillance period for follow-up bronchoscopy for early detection and possible prevention of stent-associated complications. Methods Retrospective cohort study of all patients who underwent airway stent placements at our institution from April 2010 to December 2013 for benign and malignant airway diseases. Metallic, silicone (straight, Y stent, T-tube) and hybrid stents were included in the study. Stent complications were analyzed at the time of follow-up bronchoscopy performed four to six weeks after initial stent placement or earlier if patients became symptomatic. Results The study included 134 patients of which 147 stents were placed. Follow-up bronchoscopy was performed in 94 patients. Symptomatic status at the time of follow-up bronchoscopy was not associated with stent complications [odds ratio (OR) =1.88; 95% CI: 0.79–4.45; P=0.15]. Patient age, sex, indication for stent placement, and stent location, were not associated with development of complications (all P>0.05). Compared to all other stents, hybrid stents were more likely to migrate (OR =6.60; 95% CI: 2.16–20.2; P=0.001) or obstruct by secretions (OR =2.53; 95% CI: 1.10–5.84; P=0.03). There were no complications associated with surveillance bronchoscopy. Conclusions Surveillance bronchoscopy within 4 to 6 weeks of stent placement may be useful for early detection of complications and their subsequent management, regardless of symptomatic status and indication for stent placement. Prospective multicenter studies are needed to compare optimal surveillance methods and the impact on patient mortality, morbidity and healthcare costs. PMID:29268534

Titanium-nitride-oxide-coated coronary stents: insights from the available evidence.

PubMed

Karjalainen, Pasi P; Nammas, Wail

2017-06-01

Coating of stent surface with a biocompatible material is suggested to improve stent safety profile. A proprietary process was developed to coat titanium-nitride-oxide on the stent surface, based on plasma technology that uses the nano-synthesis of gas and metal. Preclinical in vitro and in vivo investigation confirmed blood compatibility of titanium (nitride-) oxide films. Titanium-nitride-oxide-coated stents demonstrated a better angiographic outcome, compared with bare-metal stents at mid-term follow-up; however, they failed to achieve non-inferiority for angiographic outcome versus second-generation drug-eluting stents. Observational studies showed adequate clinical outcome at mid-term follow-up. Non-randomized studies showed an outcome of titanium-nitride-oxide-coated stents comparable to - or better than - first-generation drug-eluting stents at long-term follow-up. Two randomized controlled trials demonstrated comparable efficacy outcome, and a better safety outcome of titanium-nitride-oxide-coated stents versus drug-eluting stents at long-term follow-up. Evaluation by optical coherence tomography at mid-term follow-up revealed better neointimal strut coverage associated with titanium-nitride-oxide-coated stents versus drug-eluting stents; yet, neointimal hyperplasia thickness was greater. Key messages Stents coated with titanium-nitride-oxide demonstrated biocompatibility in preclinical studies: they inhibit platelet and fibrin deposition, and reduce neointimal growth. In observational and non-randomized studies, titanium-nitride-oxide-coated stents were associated with adequate safety and efficacy outcome. In randomized trials of patients with acute coronary syndrome, titanium-nitride-oxide-coated stents were associated with a better safety outcome, compared with drug-eluting stents; efficacy outcome was comparable.

High-definition multidetector computed tomography for evaluation of coronary artery stents: comparison to standard-definition 64-detector row computed tomography.

PubMed

Min, James K; Swaminathan, Rajesh V; Vass, Melissa; Gallagher, Scott; Weinsaft, Jonathan W

2009-01-01

The assessment of coronary stents with present-generation 64-detector row computed tomography scanners that use filtered backprojection and operating at standard definition of 0.5-0.75 mm (standard definition, SDCT) is limited by imaging artifacts and noise. We evaluated the performance of a novel, high-definition 64-slice CT scanner (HDCT), with improved spatial resolution (0.23 mm) and applied statistical iterative reconstruction (ASIR) for evaluation of coronary artery stents. HDCT and SDCT stent imaging was performed with the use of an ex vivo phantom. HDCT was compared with SDCT with both smooth and sharp kernels for stent intraluminal diameter, intraluminal area, and image noise. Intrastent visualization was assessed with an ASIR algorithm on HDCT scans, compared with the filtered backprojection algorithms by SDCT. Six coronary stents (2.5, 2.5, 2.75, 3.0, 3.5, 4.0mm) were analyzed by 2 independent readers. Interobserver correlation was high for both HDCT and SDCT. HDCT yielded substantially larger luminal area visualization compared with SDCT, both for smooth (29.4+/-14.5 versus 20.1+/-13.0; P<0.001) and sharp (32.0+/-15.2 versus 25.5+/-12.0; P<0.001) kernels. Stent diameter was higher with HDCT compared with SDCT, for both smooth (1.54+/-0.59 versus1.00+/-0.50; P<0.0001) and detailed (1.47+/-0.65 versus 1.08+/-0.54; P<0.0001) kernels. With detailed kernels, HDCT scans that used algorithms showed a trend toward decreased image noise compared with SDCT-filtered backprojection algorithms. On the basis of this ex vivo study, HDCT provides superior detection of intrastent luminal area and diameter visualization, compared with SDCT. ASIR image reconstruction techniques for HDCT scans enhance the in-stent assessment while decreasing image noise.

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.

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.

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

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.

Current global status of carotid artery stent placement.

PubMed

Wholey, M H; Wholey, M; Bergeron, P; Diethrich, E B; Henry, M; Laborde, J C; Mathias, K; Myla, S; Roubin, G S; Shawl, F; Theron, J G; Yadav, J S; Dorros, G; Guimaraens, J; Higashida, R; Kumar, V; Leon, M; Lim, M; Londero, H; Mesa, J; Ramee, S; Rodriguez, A; Rosenfield, K; Teitelbaum, G; Vozzi, C

1998-05-01

Our purpose was to review the current status of carotid artery stent placement throughout the world. Surveys were sent to major interventional centers in Europe, North and South America, and Asia. Information from peer-reviewed journals was also included and supplemented the survey. The survey asked various questions regarding the patients enrolled, procedure techniques, and results of carotid stenting, including complications and restenosis. Of the centers which were sent surveys, 24 responded. The total number of endovascular carotid stent procedures that have been performed worldwide to date included 2,048 cases, with a technical success of 98.6%. Complications that occurred during carotid stent placement or within a 30-day period following placement were recorded. Overall, there were 63 minor strokes, with a rate of occurrence of 3.08%. The total number of major strokes was 27, for a rate of 1.32%. There were 28 deaths within a 30-day postprocedure period, resulting in a mortality rate of 1.37%. Restenosis rates of carotid stenting have been 4.80% at 6 mo. Endovascular stent treatment of carotid artery atherosclerotic disease is growing as an alternative to vascular surgery, especially for patients that are at high risk for standard carotid endarterectomy. The periprocedural risks for major and minor strokes and death are generally acceptable at this early stage of development.

Temporary Rectal Stenting for Management of Severe Perineal Wounds in Two Dogs.

PubMed

Skinner, Owen T; Cuddy, Laura C; Coisman, James G; Covey, Jennifer L; Ellison, Gary W

Perineal wounds in dogs present a challenge due to limited local availability of skin for closure and constant exposure to fecal contaminants. This report describes temporary rectal stenting in two dogs following severe perineal wounds. Dog 1 presented with a 4 × 4 cm full-thickness perineal slough secondary to multiple rectal perforations. A 12 mm internal diameter endotracheal tube was placed per-rectum as a temporary stent to minimize fecal contamination. The stent was removed 18 days after placement, and the perineal wound had healed at 32 days post-stent placement, when a minor rectal stricture associated with mild, intermittent tenesmus was detected. Long-term outcome was deemed good. Dog 2 presented with multiple necrotic wounds with myiasis, circumferentially surrounding the anus and extending along the tail. A 14 mm internal diameter endotracheal tube was placed per-rectum. The perineal and tail wounds were managed with surgical debridement and wet-to-dry and honey dressings prior to caudectomy and negative pressure wound therapy (NPWT). Delayed secondary wound closure and stent removal were performed on day six without complication. Long-term outcome was deemed excellent. Temporary rectal stenting may be a useful technique for fecal diversion to facilitate resolution of complex perineal injuries, including rectal perforation.

A novel, ring-connected stent versus conventional GI stents: comparative study of physical properties and migration rates in a canine colon obstruction model.

PubMed

Park, Hong Suk; Choo, In Wook; Seo, Soowon; Hyun, Dongho; Lim, Sooyoun; Kim, Jae J; Hong, Saet-Byul; Min, Byung-Hoon; Do, Young Soo; Choo, Sung Wook; Shin, Sung Wook; Park, Kwang Bo; Cho, Sung Ki

2015-01-01

Migration of stents is one of the most common adverse events in covered stent placement in GI tract obstruction. To compare physical property and migration rates in a canine colon obstruction model among a novel stent and conventional stents. Comparative physical test and animal study. Medical device testing laboratory and animal laboratory. Mongrel dogs (N=26). Surgical colon obstruction followed by placement of a novel (n=13) or conventional (n=13) stent. Physical properties, migration, and adverse events. The novel stent showed better flexibility, as in a physical test of longitudinal compressibility and axial force, than did conventional stents, and it withstood the fatigue test for 10 days. In terms of radial force and tensile strength, the novel stent showed the same or better results than conventional stents. In a canine colon obstruction model, the migration rate of a novel stent was significantly lower than that of a conventional stent (2/13, 15.4% vs 8/13, 61.5%; P=.008). Animal study of limited size. The novel, ring-connected stent is more flexible and more resistant to migration than the conventional stents. Copyright © 2015 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc. All rights reserved.

Results of celiac trunk stenting during fenestrated or branched aortic endografting.

PubMed

Wattez, Hélène; Martin-Gonzalez, Teresa; Lopez, Benjamin; Spear, Rafaëlle; Clough, Rachel E; Hertault, Adrien; Sobocinski, Jonathan; Haulon, Stéphan

2016-12-01

Endovascular repair of aortic aneurysms involving the visceral segment of the aorta often requires placement of a covered bridging stent in the celiac axis (CA). The median arcuate ligament (MAL) is a fibrous arch that unites the diaphragmatic crura on either side of the aortic hiatus. The ligament may compress and distort the celiac artery and result in difficult cannulation, or stenosis and occlusion of the vessel. This study evaluated the influence of the MAL compression on the technical success and the patency of the celiac artery after branched and fenestrated endovascular aortic repair. We retrospectively analyzed a cohort of consecutive patients treated electively for complex aneurysms with branched and fenestrated endovascular aortic repair between January 2007 and April 2014. All data were collected prospectively. Analysis of preoperative computed tomography angiography on a three-dimensional workstation determined the presence of MAL compression. Patency of the CA bridging stent was assessed during follow-up by computed tomography angiography and duplex ultrasound evaluation. Statistical analysis was performed to compare the outcomes of patients with MAL (MAL+) and without MAL (MAL-) compression. Of 315 patients treated for aortic disease involving the visceral segment during the study period, 113 had endografts designed with a branch (n = 57) or fenestration (n = 56) for the CA. In 45 patients (39.8%), asymptomatic compression of the CA by the MAL was depicted (MAL+). Complex endovascular techniques were required in this group to access the CA in 16 (14.2%) patients (vs none in the MAL- group; P = .003), which lead to a failed bridging stent implantation in seven patients (6.2%). Increased operative time and dose area product were observed in the MAL+ group, but this did not reach statistical significance. In the MAL+ group, no thrombosis of the CA bridging stents were observed during follow-up; an external compression of the CA bridging stent was depicted in six patients but without hemodynamic effect on duplex ultrasound imaging. In the MAL- group, one CA bridging stent occlusion occurred owing to an embolus from a cardiac source. MAL compression is associated with good celiac trunk bridging stent patency during follow-up, but with a higher rate of technical difficulties and failed bridging stent implantation during the procedure. Copyright © 2016 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

Dissection and re-entry techniques and longer-term outcomes following successful percutaneous coronary intervention of chronic total occlusion.

PubMed

Rinfret, Stéphane; Ribeiro, Henrique Barbosa; Nguyen, Can Manh; Nombela-Franco, Luis; Ureña, Marina; Rodés-Cabau, Josep

2014-11-01

New techniques involving dissection of the subintimal space and re-entry into the true lumen increase success rates in chronic total occlusion (CTO) percutaneous coronary intervention (PCI). However, their long-term safety and efficacy were unknown. This study included a series of consecutive patients who underwent CTO PCI. All patients who did not present events were contacted 12 to 18 months after their PCI. The combined incidence of cardiac death, myocardial infarction, ischemia-driven target-vessel revascularization (TVR), or reocclusion was assessed as our primary outcome. From January 2010 to January 2013, of 212 CTOs treated in our CTO program, 192 (91%) were successfully opened (in 179 patients). Follow-up data were available for 187 CTOs (97.4%), with 82 (44%) that were opened with dissection re-entry and 105 (56%) with conventional wire escalation techniques. At a median follow-up of 398 days, the primary outcome occurred in 18 of 179 CTOs treated (10.7%), driven by TVR. No patient died from cardiac causes. Eleven CTOs (15.2%) treated with dissection re-entry versus 7 CTOs (7.3%) treated with wire escalation presented with the primary outcome (p = 0.17). With multivariate adjustment, dissection re-entry techniques had no significant impact on outcomes. However, treatment of an in-stent occlusion was independently associated with TVR (hazards ratio >6.0, p <0.001). In conclusion, dissection re-entry techniques have minimal impact on long-term outcomes after CTO PCI, which are favorable in most patients. However, treatment of an in-stent occlusion and use of sirolimus-eluting stent were predictors of subsequent adverse outcomes. Copyright © 2014 Elsevier Inc. All rights reserved.

TAVR Through Heavily Calcified Aorta Following Atheroma Retrieval With the "Elevator" Technique.

PubMed

Senguttuvan, N Boopathy; Ellozy, Sharif; Tejani, Furqan; Kovacic, Jason; Kini, Annapoorna S; Sharma, Samin K; Dangas, George D

2015-10-01

An 86-year-old Caucasian female with severe symptomatic, inoperable aortic stenosis was accepted for high-risk transfemoral transcatheter aortic valve replacement (TAVR) approach due to severe calcification of the aorta. During initial passage of a 22 Fr sheath, there was dislodgment with proximal migration of a circumferential tunnel of calcium from the infrarenal aorta. A novel "elevator" technique was used to secure and retrieve the dislodged aorta en bloc back to its original infrarenal aortic position and allow in situ fixation with stenting. A new TAVR system was then successfully placed through the stent and a 23 mm Edwards Sapien valve (Edwards Lifesciences) was implanted as planned. In case of calcification protruding into the lumen of the aorta and limiting the passage of the large valve delivery system sheath, the obstruction can be managed by stenting the calcification against the luminal wall under fluoroscopic and intravascular-ultrasound guidance, allowing successful passage of the valve delivery system. The elevator technique allows axial transportation of any calcified vascular fragments, should they become dislodged.

Scalable Manufacturing of Metal Micro/Nanowires and Applications by Thermal Fiber Drawing Method

NASA Astrophysics Data System (ADS)

Hwang, Injoo

The objective of this study is to better understand the fundamental principal of the thermal fiber drawing process with metal-core preforms. This would enable us to overcome the fundamental limits of current thermal drawing techniques by tuning material properties of core metals and interactions between core and cladding materials using nanoparticles. Metal micro/nanowires with controlled size, aspect ratio and spatial configurations of core and cladding materials exhibit extraordinary mechanical, thermal, electrical and optical properties. These metal micro/nanowires can be utilized for widespread applications such as: thermoelectric, conductive electrode and plasmonic photonic crystal fibers. Thermal fiber drawing method has emerged as an advanced scalable manufacturing technique for micro/nanowires production due to its unique characteristics that allow mass production of continuous and arbitrary designed wires. It is of tremendous scientific and technical interests to conduct a fundamental study on thermal fiber drawing methods and to break the current limits of the crystalline metal core thermal fiber drawing process. In this study, metal core was fabricated by cold compaction of the Zinc (Zn)-Tungsten Carbide (WC) nanopowders. Our characterizations through scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) showed that WC nanoparticle are uniformly dispersed in Zn matrix. The effects of WC nanoparticles on the mechanical properties and degradation rate in Zn-WC nanocomposites were carefully analyzed by tensile, compressive, hardness, degradation and viscosity tests. Metallic stents are commonly used to expand blood vessels that have been narrowed by plaque buildup (atherosclerosis). Fabrication difficulty and other constrains of metallic stents result in high cost. Zn-WC nanocomposite microwires were controllably drawn for stent struts with a diameter of 200 ?m. Characterizations by the tensile and degradation tests of Zn-WC nanocomposite microwires validate the eligibility for stent fabrication. Single cell Zn-WC nanocomposite stents were fabricated by braiding thermally drawn Zn-WC nanocomposite microwires on a weaving stage built by 3D printing. Zn-WC nanocomposite stents with an inner diameter of 2 mm was expanded up to 10 mm without recoil by a catheter, which is thin tube inserted into human body serving in a broad range of functions. For the purpose of in vivo test, Zn-WC nanocomposite stents were deployed in a pig by percutaneous coronary intervention method (angioplasty with stent). The surgery under fluoroscopy that continuous X-ray beam is passed through the body part being examined. X-ray opaque Zn-WC nanocomposite stents were distinctly shown to be expanded by a catheter and remained without bounce back through the whole procedure. The Zn-WC nanocomposite stents were extracted from the pig a month later and studied for the degradability by SEM and EDS mapping analysis. SEM images of Zn-WC stents showed that the degradation of the stents was uniformly proceeded on the surface without fractures. While the Zn-WC nanocomposite stents stayed inside the vessel, good endothelializations between the Zn-WC stents and surrounding cell tissues as well as no acute pathological problems were discovered from this study. One of the current challenges of thermal fiber drawing process for crystalline metal nanowires is low aspect ratio (< 10,000). A molten metal nanowire in a cladding material breaks up into shorter nanowires or smaller droplets due to Plateau-Rayleigh instability. It was experimentally and theoretically shown that molten liquid tends to minimize their surface area by virtue of surface tensions. The Tomotika model introduced the relation among instability time, viscosities of core and cladding materials, the wavelength and diameter of the core fluid, and interfacial energy between core and cladding materials as specifying the Plateau-Rayleigh instability [1]. The instability time was impeded by high viscosity of the Zn-WC nanocomposite core material while the preform of Zn-WC nanocomposite was thermally drawn by the stack-and-draw method. Consequently, high aspect ratio (> 1,500,000) of Zn-WC nanocomposite nanowires that are 200 nm in diameter and up to 31 cm length were achieved. Herein, we present that WC nanoparticles decreased interfacial energy between metal and glass due to its inherent characteristic such as partly metallic bonding. As a result, the nanoparticle can play the role of anchors to prevent breakage by capillary instability in nanoscale thermal fiber drawing process. Zn-WC nanocomposite nanowires surrounded by borosilicate glass were shown through the TEM (transmission electron microscope) diffraction patterns. By the electrical resistance test, not onlythe electrical resistance and but also the continuity of the Zn-WC nanocomposite nanowires was presented. (Abstract shortened by ProQuest.).

Time Sequence Evaluation of Biliary Stent Occlusion by Dissection Analysis of Retrieved Stents.

PubMed

Kwon, Chang-Il; Gromski, Mark A; Sherman, Stuart; Easler, Jeffrey J; El Hajj, Ihab I; Watkins, James; Fogel, Evan L; McHenry, Lee; Lehman, Glen A

2016-08-01

Multiple factors can affect the occlusion of plastic stents. Previous data demonstrate that side holes may induce more biofilm formation probably via microturbulence and bile flow disturbances that could lead to occlusion. These results, however, have not been replicated in subsequent clinical studies with different methods. The objective of this study is to evaluate the physical characteristics of plastic stent occlusion over time. This is a plastic stent sequential analysis study. Biliary stents removed via ERCP from February 24, 2015, to June 2, 2015, were included. One hundred and forty-eight retrieved straight-type plastic stents were longitudinally cut by a custom-made cutting device. These dissected stents were then evaluated in detail with regard to the location of stent occlusion and the stent patency period. Location of stent occlusive debris was the primary outcome in this study. Biofilm formations and occlusions by debris were sequentially but separately tallied. Biofilm formations were initially seen around the side hole areas within 30 days and spread to the entire stent by 60 days. Then, occlusion process by debris was mainly initiated by 80 days and progressed to full occlusion by median of 90 days. Although some occlusions were also observed around the side hole areas within 30 days, affected areas were more widely observed after biofilm formation. This study is the first to attempt to describe the distribution of stent occlusions over time. These observations may help guide future stent development.

Scanning Electron Microscopic Features of Nasolacrimal Silastic Stents Retained for Prolong Durations Following Dacryocystorhinostomy.

PubMed

Ali, Mohammad Javed; Baig, Farhana; Lakshman, Mekala; Naik, Milind N

2016-01-01

The aims of this study were to examine the scanning electron microscopic features of silastic nasolacrimal duct stents retained for long durations following a dacryocystorhinostomy. A prospective interventional study was performed on stents retrieved from patients who were lost to follow up after a dacryocystorhinostomy with Crawford stent insertion. Long duration was defined as stents retrieved at a minimum of 1 year following a dacryocystorhinostomy. None of the patients had any evidence of postoperative infection. After removal, the stent segments were subjected to biofilm and physical deposit analysis using standard protocols of scanning electron microscopy. These stent segments were compared against sterile stents which acted as controls. A total of 7 stents were studied. Five were consecutive patient samples, and 2 were sterile stents. All the 5 stents were retrieved from patients who were lost to follow up for a minimum of 12 months following surgery. The mean duration of intubation at retrieval was 21 months. All the stents demonstrated evidence of biofilm formation and physical deposits. However, as the duration of retention increased, the deposits and biofilms were noted to be progressively denser, multilayered and extensive. Certain areas demonstrated thick biofilm integration with the deposits. Polymicrobial communities were noted within the exopolysaccharide matrix. This is the first study to exclusively report on scanning electron microscopic features of lacrimal stents retained for long durations. Further studies on physical elements within the deposits and protein analysis would provide more insights into stent-tissue interactions.

Frequency of occurrence of urinary tract infection in double j stented versus non-stented renal transplant recipients.

PubMed

Shohab, Durre; Khawaja, Athar; Atif, Emad; Jamil, Imran; Ali, Iftikhar; Akhter, Saeed

2015-01-01

Prophylactic ureteric stenting in renal transplant recipients prevents major surgical complications such as ureteric leak and obstruction on the one hand while, on the other hand, it is associated with complications like urinary tract infections (UTI), hematuria, stent migration, stent encrustation and forgotten stents. UTI is documented to be most common complication associated with double J (DJ) stent. In this retrospective observational study involving 157 patients, we compared the frequency of occurrence of UTI in DJ-stented versus non-stented renal transplant recipients. The study patients had undergone renal transplantation, with or without DJ-stenting, between January 2007 and June 2012. The mean age of the study subjects was 34.01 ± 14.63 years. The patients were followed-up for one year post-transplantation with regular evaluation, including detailed assessment, complete blood picture, renal function tests, routine urine examination and cultures. Data were collected through chart and electronic record review. Of a total of 157 patients, 61 (38.85%) developed UTI, including 30 of 74 stented patients (40.54%) and 31 of 83 non-stented renal transplant recipients (37.34%). Relative risk was calculated to be 1.08. The mean serum creatinine at the end of one year was 1.47 mg/dL in DJ-stented patients and 1.36 mg/dL in nonstented patients. Our study suggests that there is no significant difference in the frequency of UTI between DJ-stented and non-stented renal transplant recipients.

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.

Stent recanalization of carotid tonsillar loop dissection using the Enterprise vascular reconstruction device.

PubMed

Rahal, Jason P; Gao, Bulang; Safain, Mina G; Malek, Adel M

2014-07-01

Although advances in endovascular techniques have permitted reconstruction of intimal dissections and related pseudoaneurysms of the extracranial cervical internal carotid artery, highly tortuous tonsillar loop anatomic variants still pose an obstacle to conventional extracranial self-expanding carotid stents. During a 12 year period, nine of 48 cases with cervical carotid dissections were associated with a tonsillar loop. Five patients required endovascular treatment, which was performed using a microcatheter-based technique with the low-profile Enterprise vascular reconstruction device (Codman Neurovascular, Raynham, MA, USA). Technical, radiographic, and clinical outcomes were analyzed for each patient. Dissection etiology was spontaneous in three patients, iatrogenic in one, and traumatic in one. Four near-occlusive tonsillar loop dissections were successfully recanalized during the acute phase. Dissection-related stenosis improved from 90±22% to 31±13%, with tandem stents needed in three instances to seal the inflow zone. There were no procedure-related transient ischemic attacks (TIA), minor/major strokes, or deaths. Angiographic follow-up for a mean of 28.0±21.6 months showed all stents were patent, with average stenosis of 25.2±12.2%. Focal ovalization and kinking of the closed-cell design was noted at the sharpest curve in one patient. Clinical outcome (follow-up of 28.1±21.5 months) demonstrated overall improvement with no clinical worsening, new TIA, or stroke. Tonsillar loop-associated carotid dissections can be successfully and durably recanalized using the low-profile Enterprise stent with an excellent long-term patency rate and low procedural risk. The possibility of stent kinking and low radial force should be considered when planning reconstruction with this device. Copyright © 2014 Elsevier Ltd. All rights reserved.

Endovascular Stenting of Peripheral Infected Aneurysms: A Temporary Measure or a Definitive Solution in High-Risk Patients

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

Riga, Celia, E-mail: c.riga@imperial.ac.u; Bicknell, Colin; Jindal, Ravul

The purpose of this study was to demonstrate the use of endovascular technology in the management of peripheral infected aneurysms in high-risk patients as a temporary measure or definitive solution. Five cases underwent successful endovascular stenting of infected aneurysms of the subclavian, femoral, and carotid arteries. All these patients were at high risk for open surgery. Covered stents were placed by percutaneous approach under local anesthesia in all patients. Postoperatively, antibiotics were continued for 3 months. A literature review using the Medline database was also undertaken, and all the relevant papers on endovascular management of peripheral infected aneurysms were takenmore » into account. Stent deployment was successful in all patients. One patient died of mediastinal sepsis and another from type A aortic dissection 5 weeks later. Two patients required drainage of the infected hematoma. Three patients did well at a median follow-up of 1 year, with no evidence of sepsis. A review of the literature shows promising early and midterm results. Most early reports were of single cases, reflecting the low incidence of peripheral infected aneurysms. We conclude that further development of endoluminal techniques and long-term follow-up to establish the durability of stenting could potentially lead to a decrease in the high morbidity and mortality rates associated with infected aneurysmal disease in this high-risk group of patients.« less

Endovascular stenting of peripheral infected aneurysms: a temporary measure or a definitive solution in high-risk patients.

PubMed

Riga, Celia; Bicknell, Colin; Jindal, Ravul; Cheshire, Nicholas; Hamady, Mohamad

2008-01-01

The purpose of this study was to demonstrate the use of endovascular technology in the management of peripheral infected aneurysms in high-risk patients as a temporary measure or definitive solution. Five cases underwent successful endovascular stenting of infected aneurysms of the subclavian, femoral, and carotid arteries. All these patients were at high risk for open surgery. Covered stents were placed by percutaneous approach under local anesthesia in all patients. Postoperatively, antibiotics were continued for 3 months. A literature review using the Medline database was also undertaken, and all the relevant papers on endovascular management of peripheral infected aneurysms were taken into account. Stent deployment was successful in all patients. One patient died of mediastinal sepsis and another from type A aortic dissection 5 weeks later. Two patients required drainage of the infected hematoma. Three patients did well at a median follow-up of 1 year, with no evidence of sepsis. A review of the literature shows promising early and midterm results. Most early reports were of single cases, reflecting the low incidence of peripheral infected aneurysms. We conclude that further development of endoluminal techniques and long-term follow-up to establish the durability of stenting could potentially lead to a decrease in the high morbidity and mortality rates associated with infected aneurysmal disease in this high-risk group of patients.

Preliminary study for a newly designed silicone stent and delivery system for canine obstructive tracheal disease.

PubMed

Kim, Dae-Hyun; Choi, Chi-Bong; Chung, Wook-Hun; Lee, Sung-Ho; Lee, A-Jin; Jeong, Jae-Seung; Kim, Ho-Joong; Kim, Hwi-Yool

2012-10-01

The goal of this study was to prove the possibility of using silicone stents broadly used for human medicine in canine obstructive tracheal disease. A silicone stent anatomically designed for canine trachea was tested on 5 beagle dogs for 8 weeks. The stent was carefully inserted using a newly developed delivery device under fluoroscopic guidance. There were no technical difficulties in placing the stent during the procedure. Previously reported complications of airway stenting such as stent migration or granulation tissue formation did not occur in any of the cases. In addition, removal of the stent was as simple as inserting it, and complications were absent. The stent introduced in this study could possibly be applied to various canine obstructive tracheal diseases.

Treatment protocol based on assessment of clot quality during endovascular thrombectomy for acute ischemic stroke using the Trevo stent retriever

PubMed Central

Ishikawa, Kojiro; Ohshima, Tomotaka; Nishihori, Masahiro; Imai, Tasuku; Goto, Shunsaku; Yamamoto, Taiki; Nishizawa, Toshihisa; Shimato, Shinji; Kato, Kyozo

2016-01-01

ABSTRACT The optional endovascular approach for acute ischemic stroke is unclear. The Trevo stent retriever can be used as first-line treatment for fast mechanical recanalization. The authors developed a treatment protocol for acute ischemic stroke based on the assessment of clot quality during clot removal with the Trevo. This prospective single-center study included all patients admitted for acute ischemic stroke between July 2014 and February 2015, who underwent emergency endovascular treatment. According to the protocol, the Trevo was used for first-line treatment. Immediately after the Trevo was deployed, the stent delivery wire was pushed to open the stent by force (ACAPT technique). Clot quality was assessed on the basis of the perfusion status after deployment of the Trevo; continued occlusion or immediate reopening either reoccluded or maintained after the stent retriever had been in place for 5 min. If there was no obvious clot removal after the first pass with the Trevo, according to the quality of the clot, either a second pass was performed or another endovascular device was selected. Twelve consecutive patients with acute major cerebral artery occlusion were analyzed. Thrombolysis in cerebral infarction score 2b and 3 was achieved in 11 patients (91.7%) and 9 (75%) had a good clinical outcome after 90 days based on a modified Rankin scale score ≤ 2. Symptomatic intracranial hemorrhage occurred in 1 patient (8.3%). The overall mortality rate was 8.3%. Endovascular thrombectomy using the Trevo stent retriever for first-line treatment is feasible and effective. PMID:27578909

To stent or not to stent: the use of transanastomotic biliary stents in liver transplantation and patient outcomes.

PubMed

Ong, Michelle; Slater, Kellee; Hodgkinson, Peter; Dunn, Nathan; Fawcett, Jonathan

2018-06-01

There is no substantial evidence for the use of biliary stents in bile duct reconstruction during liver transplantation. A longitudinal, retrospective cohort study was performed to compare biliary complications between stented and non-stented patients between 2011 and 2015 at the Princess Alexandra Hospital, Brisbane, Australia. We found no significant difference in biliary complications between stented and non-stented groups. Stented patients were 3.31 times as likely to require subsequent intervention, mainly in the form of stent removal. These results suggest that there is limited benefit in the placement of endobiliary stents in liver transplantation. Given that this was purely an observational study, causality cannot be proven and a prospective cohort trial would be beneficial in further defining these relationships. © 2018 Royal Australasian College of Surgeons.

Drug-eluting versus bare-metal coronary stents: where are we now?

PubMed

Amoroso, Nicholas S; Bangalore, Sripal

2012-11-01

Drug-eluting stents have dramatically reduced the risk of restenosis, but concerns of an increased risk of stent thrombosis have provided uncertainty about their use. Recent studies have continued to show improved procedural and clinical outcomes with drug-eluting stents both in the setting of acute coronary syndromes and stable coronary artery disease. Newer generation drug-eluting stents (especially everolimus-eluting stents) have been shown to be not only efficacious but also safe with reduced risk of stent thrombosis when compared with bare-metal stents, potentially changing the benchmark for stent safety from bare-metal stents to everolimus-eluting stents. While much progress is being made in the development of bioabsorbable polymer stents, nonpolymer stents and bioabsorbable stent technology, it remains to be seen whether these stents will have superior safety and efficacy outcomes compared with the already much improved rates of revascularization and stent thrombosis seen with newer generation stents (everolimus-eluting stents and resolute zotarolimus-eluting stents).

Mechanical design of an intracranial stent for treating cerebral aneurysms.

PubMed

Shobayashi, Yasuhiro; Tanoue, Tetsuya; Tateshima, Satoshi; Tanishita, Kazuo

2010-11-01

Endovascular treatment of cerebral aneurysms using stents has advanced markedly in recent years. Mechanically, a cerebrovascular stent must be very flexible longitudinally and have low radial stiffness. However, no study has examined the stress distribution and deformation of cerebrovascular stents using the finite element method (FEM) and experiments. Stents can have open- and closed-cell structures, and open-cell stents are used clinically in the cerebrovasculature because of their high flexibility. However, the open-cell structure confers a risk of in-stent stenosis due to protrusion of stent struts into the normal parent artery. Therefore, a flexible stent with a closed-cell structure is required. To design a clinically useful, highly flexible, closed-cell stent, one must examine the mechanical properties of the closed-cell structure. In this study, we investigated the relationship between mesh patterns and the mechanical properties of closed-cell stents. Several mesh patterns were designed and their characteristics were studied using numerical simulation. The results showed that the bending stiffness of a closed-cell stent depends on the geometric configuration of the stent cell. It decreases when the stent cell is stretched in the circumferential direction. Mechanical flexibility equal to an open-cell structure was obtained in a closed-cell structure by varying the geometric configuration of the stent cell. Copyright © 2010 IPEM. Published by Elsevier Ltd. All rights reserved.

Predictors of early stent occlusion among plastic biliary stents.

PubMed

Khashab, Mouen A; Kim, Katherine; Hutfless, Susan; Lennon, Anne Marie; Kalloo, Anthony N; Singh, Vikesh K

2012-09-01

A major disadvantage of plastic biliary stents is their short patency rates. The aim of this study was to identify predictors of early stent occlusion among patients receiving conventional plastic biliary stents. Early stent occlusion was defined as worsening cholestatic liver test results of a severity sufficiently significant to warrant ERCP with stent exchange prior to the planned stent exchange, or as symptoms of cholangitis. The association of cumulative stent diameter, demographics, stricture location, procedure indication, Charlson comorbidity index, history of prior early stent occlusion, presence of gallbladder, and performance of sphincteromy with the occurrence of early stent occlusion was studied using logistic regression and multivariate analysis. Our patient cohort comprised 343 patients (mean age 59.3 years) who underwent 561 ERCP procedures with the placement of one or more plastic biliary stents (mean number of stents per procedure 1.2, mean total diameter of stents per procedure 12 Fr). Early stent occlusion occurred in 73 (13 %) procedures. Female gender was protective against early stent occlusion (adjusted OR 0.54, 95 % CI 0.32-0.90, p = 0.02), while hilar stricture location was independently associated with a significantly increased risk of early stent occlusion (adjusted OR 3.41, 95 % CI 1.68-6.90, p = 0.0007). Early occlusion of conventional biliary stents occurred in 13 % of cases. While female gender decreased the risk of early stent occlusion, hilar stricture location was a significant predictor of early stent occlusion. Our results suggest that physicians should consider early elective stent exchange in patients with hilar strictures.

Rationale and design of a multidisciplinary national real-world registry on carotid stenting: the Italian Registry for Carotid Stenting (RISC).

PubMed

Biasi, Giorgio M; Deleo, Gaetano; Froio, Alberto; Cremonesi, Alberto; Inglese, Luigi; Lavitrano, Marialuisa; Setacci, Carlo

2006-04-01

The Registro Italiano per lo Stenting Carotideo (RISC, Italian Registry for Carotid Stenting) has been organized by Italian specialists from different disciplines directly involved in the prevention of stroke due to carotid plaques through stenting of carotid lesions. The Registry has been endorsed by the national societies of 4 different specialties: vascular surgery, interventional cardiology, radiology, and neuroradiology. Each society contributed in the planning stage. The basis for the registry is to collect data on carotid stenting procedures performed by different specialists with different techniques in a "real-world" setting without the limitations of a randomized clinical trial. The Registry was funded to enroll at least 1200 patients over a minimum period of 36 months. The results will be analyzed using the intention-to-treat principle and are anticipated in late 2006. Primary endpoints of the registry are the 30-day combined death and stroke rate and the occurrence of restenosis and ipsilateral neurological deficit at 12 and 24 months. Considerable attention has been paid to the registry's quality control program to ensure scientific validation. An online database facilitates the collection of data with speed and accuracy.

Endoscopic Gallbladder Drainage for Acute Cholecystitis

PubMed Central

Widmer, Jessica; Alvarez, Paloma; Sharaiha, Reem Z.; Gossain, Sonia; Kedia, Prashant; Sarkaria, Savreet; Sethi, Amrita; Turner, Brian G.; Millman, Jennifer; Lieberman, Michael; Nandakumar, Govind; Umrania, Hiren; Gaidhane, Monica

2015-01-01

Background/Aims Surgery is the mainstay of treatment for cholecystitis. However, gallbladder stenting (GBS) has shown promise in debilitated or high-risk patients. Endoscopic transpapillary GBS and endoscopic ultrasound-guided GBS (EUS-GBS) have been proposed as safe and effective modalities for gallbladder drainage. Methods Data from patients with cholecystitis were prospectively collected from August 2004 to May 2013 from two United States academic university hospitals and analyzed retrospectively. The following treatment algorithm was adopted. Endoscopic retrograde cholangiopancreatography (ERCP) with sphincterotomy and cystic duct stenting was initially attempted. If deemed feasible by the endoscopist, EUS-GBS was then pursued. Results During the study period, 139 patients underwent endoscopic gallbladder drainage. Among these, drainage was performed in 94 and 45 cases for benign and malignant indications, respectively. Successful endoscopic gallbladder drainage was defined as decompression of the gallbladder without incidence of cholecystitis, and was achieved with ERCP and cystic duct stenting in 117 of 128 cases (91%). Successful endoscopic gallbladder drainage was also achieved with EUS-guided gallbladder drainage using transmural stent placement in 11 of 11 cases (100%). Complications occurred in 11 cases (8%). Conclusions Endoscopic gallbladder drainage techniques are safe and efficacious methods for gallbladder decompression in non-surgical patients with comorbidities. PMID:26473125

Malignant Ureteral Obstruction: Functional Duration of Metallic versus Polymeric Ureteral Stents

PubMed Central

Chow, Po-Ming; Chiang, I-Ni; Chen, Chia-Yen; Huang, Kuo-How; Hsu, Jui-Shan; Wang, Shuo-Meng; Lee, Yuan-Ju; Yu, Hong-Jeng; Pu, Yeong-Shiau; Huang, Chao-Yuan

2015-01-01

Background Ureteral obstruction caused by extrinsic compression is often associated with intra-abdominal cancers. Internal drainage with ureteral stents is typically the first-line therapy to relieve such obstructions. Novel designs of ureteral stents made of different materials have been invented to achieve better drainage. In this study, we described the functional outcomes of a Resonance metallic ureteral stent (Cook Medical, Bloomington, Indiana, USA) in patients with malignant ureteral obstruction and compare the functional duration of Resonance stents with regular polymeric stents in the same cohort. Methods Cancer patients who received polymeric stents and subsequent Resonance stents for ureteral obstruction between July 2009 and November 2012 were included in a chart review. Stent failure was detected by clinical symptoms, imaging studies, and renal function tests. The functional durations of each stent were calculated, and possible factors affecting stent patency were investigated. Results A total of 50 stents were successfully inserted into 50 ureteral units in 42 patients with malignant ureteral obstruction. There were 7 antegrade stents and 43 retrograde stents. There were no major complications. Stent-related symptoms were similar in both kinds of stents. After polymeric stents were replaced with Resonance metallic stents, hydronephrosis subsided or remained stable in 90% (45/50) of the ureteral units. Serum creatinine decreased or remained stable in 90% (38/42) of these patients. The Resonance stent exhibited a mean increase in functional duration of 4 months compared with the polymeric stents (p<0.0001), and 50% (25/50) of the Resonance stents exhibited a significant increase in functional duration (more than 3 months). Pre-operative serum creatinine < 2 was associated with a substantial increase in stent duration. Conclusions Resonance stents are effective and safe in relieving malignant ureteral obstructions after polymeric stents failure. Resonance stents can provide a longer functional duration than polymeric stents and should be offered as an option for internal drainage. PMID:26267140

Stent-Assisted Coil Embolization of a Mycotic Renal Artery Aneurysm by Use of a Self-Expanding Neurointerventional Stent

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

Rabellino, Martin, E-mail: jmrabellino@hotmail.com; Garcia-Nielsen, Luis, E-mail: luisgarcia@hospiten.es; Zander, Tobias, E-mail: tobiaszander@hospiten.es

2011-02-15

Mycotic aneurysms are uncommon, especially those located in visceral arteries. We present a case of a patient with two visceral mycotic aneurysms due to bacterial endocarditis, one located in right upper pole renal artery and the second in the splenic artery. Both aneurysms were treated as endovascular embolization using microcoils. In the aneurysm located at the renal artery, the technique of stent-assisted coils embolization was preferred to avoid coils migration due to its wide neck. The stent used was the Solitaire AB, which was designed for the treatment of intracranial aneurysms and was used recently in acute stroke as amore » mechanical thrombectomy device. Complete embolization of the aneurysm was achieved, preserving all the arterial branches without nephrogram defects in the final angiogram.« less

Management of refractory esophageal stenosis in the pediatric age.

PubMed

Alberca de Las Parras, Fernando; Navalón Rubio, María; Egea Valenzuela, Juan

2016-10-01

Refractory esophageal stenosis (RES) is a major health problem in the pediatric population. Several techniques such as stent placement or C-mitomycin (CM) have been described as alternative treatments. We present our experience with both techniques, in our case with biodegradable stents (BS) and sometimes the association with stents and CM. Six patients have been included: 2 post-operative fistulas in patients with type I esophageal atresia; 1 operated atresia without fistula; and 3 caustic strictures. 5 BS were placed in 4 children: 3 of them in cases of atresia (2 prosthesis in one case) and the other one in a case of stricture. CM was used in 5 cases: in 2 of them from the beginning, and in the other 3 cases after failure of the stent. When placed in fistulas, BS were fully covered. One of them successfully treated the fistula, but the other one was not effective. One stenosis was successfully treated with SB (in the case of persistent fistula), but recurrence was observed in the other 2 cases. One of these was solved with CM, and the other one needed a second stent. In the remaining 2 cases (one atresia and one caustic stricture) CM was effective after 1 and 2 sessions respectively. Overall, 5 out of 6 stenosis have been successfully treated (83.3%), and 1 out of 2 fistulas (50%). Association of BS and CM has been effective in the management of RES in children.

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

Study design and rationale of the 'Balloon-Expandable Cobalt Chromium SCUBA Stent versus Self-Expandable COMPLETE-SE Nitinol Stent for the Atherosclerotic ILIAC Arterial Disease (SENS-ILIAC Trial) Trial': study protocol for a randomized controlled trial.

PubMed

Choi, Woong Gil; Rha, Seung Woon; Choi, Cheol Ung; Kim, Eung Ju; Oh, Dong Joo; Cho, Yoon Hyung; Park, Sang Ho; Lee, Seung Jin; Hur, Ae Yong; Ko, Young Guk; Park, Sang Min; Kim, Ki Chang; Kim, Joo Han; Kim, Min Woong; Kim, Sang Min; Bae, Jang Ho; Bong, Jung Min; Kang, Won Yu; Seo, Jae Bin; Jung, Woo Yong; Cho, Jang Hyun; Kim, Do Hoi; Ahn, Ji Hoon; Kim, Soo Hyun; Jang, Ji Yong

2016-06-25

The self-expandable COMPLETE™ stent (Medtronic) has greater elasticity, allowing it to regain its shape after the compression force reduces, and has higher trackability, thus is easier to maneuver through tortuous vessels, whereas the balloon-expandable SCUBA™ stent (Medtronic) has higher radial stiffness and can afford more accurate placement without geographic miss, which is important in aortoiliac bifurcation lesions. To date, there have been no randomized control trials comparing efficacy and safety between the self-expanding stent and balloon-expandable stent in advanced atherosclerotic iliac artery disease. The purpose of our study is to examine primary patency (efficacy) and incidence of stent fracture and geographic miss (safety) between two different major representative stents, the self-expanding nitinol stent (COMPLETE-SE™) and the balloon-expanding cobalt-chromium stent (SCUBA™), in stenotic or occlusive iliac arterial lesions. This trial is designed as a prospective, randomized, multicenter trial to demonstrate a noninferiority of SCUBA™ stent to COMPLETE-SE™ stent following balloon angioplasty in iliac arterial lesions, and a total of 280 patients will be enrolled. The primary end point of this study is the rate of primary patency in the treated segment at 12 months after intervention as determined by catheter angiography, computed tomography angiography, or duplex ultrasound. The SENS-ILIAC trial will give powerful insight into whether the stent choice according to deployment mechanics would impact stent patency, geographic miss, or stent fracture in patients undergoing stent implantation in iliac artery lesions. National Institutes of Health Clinical Trials Registry (ClinicalTrials.gov identifier: NCT01834495 ), registration date: May 8, 2012.

Stenting for symptomatic intracranial vertebrobasilar artery stenosis: 30-day results in a high-volume stroke center.

PubMed

Liu, Lian; Zhao, Xiaojing; Mo, Dapeng; Ma, Ning; Gao, Feng; Miao, Zhongrong

2016-04-01

Symptomatic intracranial vertebrobasilar artery stenosis (IVBS) carries a high annual risk of recurrent stroke. Endovascular therapy was a promising technique but recent trials suggest it may carry a risk of periprocedual complications especially in inexperienced hands. This prospective study was to evaluate the safety of endovascular therapy for severe symptomatic IVBS in a high volume stroke centre. Patients with symptomatic IVBS caused by 70-99% stenosis despite medical treatment of at least one antiplatelet agent and statin were enrolled. The patients were treated either with balloon-mounted stent or balloon pre-dilation plus self-expanding stent as determined by the operators following a guideline. The primary outcome was 30-day stroke, transient ischemic attack (TIA) and death after stenting. The secondary outcome was successful stent deployment. The baseline characteristics and outcomes of patients with basilar artery (BA) lesions and patients with vertebral artery V4 segment lesions (BA group vs V4 group) were compared. And the outcome of different Mori type lesions was also compared. From September 2013 to September 2014, 105 patients with stroke or TIA due to intracranial IVBS were screened and 97 patients were treated by stenting, including 52 patients with BA stenosis and 45 patients with V4 stenosis. The rate of 30-day stroke, TIA and death was 7.1%. All the three strokes happened in the BA group and were perforator strokes. The successful stent deployment rate was 100%. General anesthesia was more preferred in the BA group than in the V4 groups (96.2% vs 75.6%, p=0.005). The Apollo stent was used more for Mori A lesions (30.5% vs 7.9%, p=0.011) and had lower degree of residual stenosis (8.6% vs 12.6%, p=0.014) than Wingspan stent. Mori C lesions were more likely to have higher degree of residual stenosis than Mori A lesion (15.3% vs 7.4%, p=0.005). The short-term safety of endovascular stenting for patients with severe symptomatic IVBS in a high volume stroke centre was acceptable. Mori A lesions may have lower residual stenosis rate than the Mori C type lesions. Copyright © 2016. Published by Elsevier B.V.

Multislice spiral computed tomography for the evaluation of stent patency after left main coronary artery stenting: a comparison with conventional coronary angiography and intravascular ultrasound.

PubMed

Van Mieghem, Carlos A G; Cademartiri, Filippo; Mollet, Nico R; Malagutti, Patrizia; Valgimigli, Marco; Meijboom, Willem B; Pugliese, Francesca; McFadden, Eugene P; Ligthart, Jurgen; Runza, Giuseppe; Bruining, Nico; Smits, Pieter C; Regar, Evelyn; van der Giessen, Willem J; Sianos, Georgios; van Domburg, Ron; de Jaegere, Peter; Krestin, Gabriel P; Serruys, Patrick W; de Feyter, Pim J

2006-08-15

Surveillance conventional coronary angiography (CCA) is recommended 2 to 6 months after stent-supported left main coronary artery (LMCA) percutaneous coronary intervention due to the unpredictable occurrence of in-stent restenosis (ISR), with its attendant risks. Multislice computed tomography (MSCT) is a promising technique for noninvasive coronary evaluation. We evaluated the diagnostic performance of high-resolution MSCT to detect ISR after stenting of the LMCA. Seventy-four patients were prospectively identified from a consecutive patient population scheduled for follow-up CCA after LMCA stenting and underwent MSCT before CCA. Until August 2004, a 16-slice scanner was used (n = 27), but we switched to the 64-slice scanner after that period (n = 43). Patients with initial heart rates > 65 bpm received beta-blockers, which resulted in a mean periscan heart rate of 57 +/- 7 bpm. Among patients with technically adequate scans (n = 70), MSCT correctly identified all patients with ISR (10 of 70) but misclassified 5 patients without ISR (false-positives). Overall, the accuracy of MSCT for detection of angiographic ISR was 93%. The sensitivity, specificity, and positive and negative predictive values were 100%, 91%, 67%, and 100%, respectively. When analysis was restricted to patients with stenting of the LMCA with or without extension into a single major side branch, accuracy was 98%. When both branches of the LMCA bifurcation were stented, accuracy was 83%. For the assessment of stent diameter and area, MSCT showed good correlation with intravascular ultrasound (r = 0.78 and 0.73, respectively). An intravascular ultrasound threshold value > or = 1 mm was identified to reliably detect in-stent neointima hyperplasia with MSCT. Current MSCT technology, in combination with optimal heart rate control, allows reliable noninvasive evaluation of selected patients after LMCA stenting. MSCT is safe to exclude left main ISR and may therefore be an acceptable first-line alternative to CCA.

Dedicated bifurcation stents

PubMed Central

Pillai, Ajith Ananthakrishna; Jayaraman, Balachander

2012-01-01

Bifurcation percutaneous coronary intervention (PCI) is still a difficult call for the interventionist despite advancements in the instrumentation, technical skill and the imaging modalities. With major cardiac events relate to the side-branch (SB) compromise, the concept and practice of dedicated bifurcation stents seems exciting. Several designs of such dedicated stents are currently undergoing trials. This novel concept and pristine technology offers new hope notwithstanding the fact that we need to go a long way in widespread acceptance and practice of these gadgets. Some of these designs even though looks enterprising, the mere complex delivering technique and the demanding knowledge of the exact coronary anatomy makes their routine use challenging. PMID:22572498

A comparative evaluation of early stent occlusion among biliary conventional versus wing stents.

PubMed

Khashab, Mouen A; Hutfless, Susan; Kim, Katherine; Lennon, Anne Marie; Canto, Marcia I; Jagannath, Sanjay B; Okolo, Patrick I; Shin, Eun Ji; Singh, Vikesh K

2012-06-01

Conventional plastic stents with a lumen typically have limited patency. The lumenless wing stent was engineered to overcome this problem. The objective of this study was to compare the incidence of early stent occlusion (symptomatic occlusion/cholangitis necessitating re-insertion within 90 days) for wing stents and conventional plastic stents. Patients with biliary pathology treated with plastic biliary stenting during the period 2003-2009 comprised the study cohort. Patients who had at least one biliary wing stent placed comprised the wing stent group, whereas patients who underwent only conventional stent plastic placement comprised the conventional stent group. Patients were stratified by indication: benign biliary strictures (group 1), malignant biliary strictures (group 2), or benign biliary non-stricture pathology (group 3). The association of stent type with the occurrence of primary outcome by indication was analyzed by use of multivariable logistic regression. Three-hundred and forty-six patients underwent 612 ERCP procedures with placement of plastic biliary stent(s). On multivariate analysis, early stent occlusion did not differ between the wing and conventional groups in groups 1, 2, and 3. Among patients who achieved primary outcome in group 2, significantly fewer patients in the wing group had cholangitis (6.7% vs. 39.1%, P = 0.03). Among patients who achieved primary outcome in group 3, significantly fewer patients in the wing group had cholangitis (10% vs. 50%, P = 0.03). Early stent occlusion was similar for wing stents and conventional plastic stents. Wing stents, however, were associated with a lower incidence of cholangitis in patients with malignant biliary obstruction and benign non-stricturing biliary pathology.

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

Computational Study of Axial Fatigue for Peripheral Nitinol Stents

NASA Astrophysics Data System (ADS)

Meoli, Alessio; Dordoni, Elena; Petrini, Lorenza; Migliavacca, Francesco; Dubini, Gabriele; Pennati, Giancarlo

2014-07-01

Despite their success as primary treatment for vascular diseases, Nitinol peripheral stents are still affected by complications related to fatigue failure. Hip and knee movements during daily activities produce large and cyclic deformations of the superficial femoral artery, that concomitant to the effects of pulsatile blood pressure, may cause fatigue failure in the stent. Fatigue failure typically occurs in cases of very extended lesions, which often require the use of two or more overlapping stents. In this study, finite element models were used to study the fatigue behavior of Nitinol stents when subjected to cyclic axial compression in different conditions. A specific commercial Nitinol stent was chosen for the analysis and subjected to cyclic axial compression typical of the femoral vascular region. Three different configurations were investigated: stent alone, stent deployed in a tube, and two overlapping stents deployed in a tube. Results confirm that stent oversizing has an influence in determining both the mean and amplitude strains induced in the stent and plays an important role in determining the fatigue response of Nitinol stents. In case of overlapping stents, numerical results suggest higher amplitude strains concentrate in the region close to the overlapping portion where the abrupt change in stiffness causes higher cyclic compression. These findings help to explain the high incidence of stent fractures observed in various clinical trials located close to the overlapping portion.

Endoscopic management of malignant biliary obstruction by means of covered metallic stents: primary stent placement vs. re-intervention.

PubMed

Kida, M; Miyazawa, S; Iwai, T; Ikeda, H; Takezawa, M; Kikuchi, H; Watanabe, M; Imaizumi, H; Koizumi, W

2011-12-01

Recent progress in chemotherapy has prolonged the survival of patients with malignant biliary strictures, leading to increased rates of stent occlusion. Occlusion of covered metallic stents now occurs in about half of all patients with malignant biliary strictures. The removal of metallic stents followed by placement of a second stent has been attempted, but outcomes remain controversial. The aim of the current study was to evaluate the effectiveness and safety of the primary placement and secondary placement (re-intervention) of covered metallic stents and to assess the feasibility and safety of stent removal. The study included 186 patients with unresectable malignant biliary strictures who underwent primary stent placement between October 2001 and March 2010.  Covered biliary self-expandable metal stents (SEMSs) were removed in 39 of these patients, and 36 underwent re-intervention. The patency times, occlusion rates of the first stent and re-intervention, success rates of stent removal, and complications were investigated. Covered SEMSs were placed in 186 patients. The median patency time of the first stent was 352 days. Stent occlusion occurred in 48.9 % of the patients and was mainly caused by debris or food residue (37 %), dislocation (19 %), and migration with hyperplasia (19 %). Stent removal was attempted in 50 patients and was successful without complication in 39 (78 %). Most of the patients in whom stent removal was unsuccessful had migration with hyperplasia. The median patency time of the second stent was 263 days. The stent patency time did not significantly differ between the first and the second stent. Covered SEMSs could be safely removed at the time of stent occlusion. Patency rates were similar for initial stent placement and re-intervention. © Georg Thieme Verlag KG Stuttgart · New York.

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

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.

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.

Flow-diverting Stent in the Treatment of Cervical Carotid Dissection and Pseudoaneurysm: Review of Literature and Case Report.

PubMed

Baptista-Sincos, Anna Paula Weinhardt; Simplício, Aline Bigatão; Sincos, Igor Rafael; Leaderman, Alex; Neto, Fernando Saliture; Moraes, Adjaldes; Aun, Ricardo

2018-01-01

The endovascular technique has been recommended over the past few years to extracranial carotid dissection and pseudoaneurysm with promising results, especially after medical therapy failure. Flow-diverting stents are an alternative for complex cases. These stents have proven to be effective treatment devices for intracranial aneurysms. The reference list of Pham's systematic review, published in 2011, and Seward's literature review, published in 2015, was considered, as well as all new articles with eligible features. Search was conducted on specific databases: MEDLINE and Literatura Latino-Americana e do Caribe em Ciências da Saúde. For carotid dissection and pseudoaneurysm, our review yielded 3 published articles including 12 patients. The technical success rate of flow-diverting stent was 100% with no procedural complication described. Mean clinical follow-up was 27.2 months (range 5-48), and in 5 months' angiographic follow-up, all lesions had healed. No new neurological events were reported during the clinical follow-up. Flow diverter stent use on intracranial and peripheral vascular surgery demonstrates satisfactory initial results, but it is still under investigation. There are very few cases treated till now and the initial results with flow-diverting stents to cervical carotid dissection are promising. In well-selected cases, where simple embolization or conventional stent is not appropriate, this technic may be considered. Copyright © 2017 Elsevier Inc. All rights reserved.

Biodegradable stents for the treatment of refractory or recurrent benign esophageal stenosis.

PubMed

Imaz-Iglesia, Iñaki; García-Pérez, Sonia; Nachtnebel, Anna; Martín-Águeda, Belén; Sánchez-Piedra, Carlos; Karadayi, Bilgehan; Demirbaş, Ali Rıza

2016-06-01

Esophageal stents are used for the treatment of refractory and recurrent dyphagias. In 2007, esophageal biodegradable stents (EBS) were authorised as an alternative to existing metal and plastic stents in Europe. The advantages claimed for EBS are fewer complications concerning tissue ingrowth, stent migration and stent removal. We performed a systematic review to evaluate the efficacy and safety of EBS compared to fully-covered self-expanding metal stents, self-expanding plastic stents, and esophageal dilation for the treatment of refractory or recurrent benign esophageal stenosis. Three comparative studies (one randomized controlled trial and two cohort studies) were assessed. The studies used different inclusion criteria, had a very small (sample) size and the quality of the evidence was very low. Expert commentary: The current evidence is insufficient to determine the relative efficacy or safety of esophageal biodegradable stents. The results of this systematic review should be updated once new evidence is available.

Reversed Frozen Elephant Trunk Technique to Treat a Type II Thoracoabdominal Aortic Aneurysm.

PubMed

Debus, E Sebastian; Kölbel, Tilo; Wipper, Sabine; Diener, Holger; Reiter, Beate; Detter, Christian; Tsilimparis, Nikolaos

2017-04-01

To describe a hybrid technique of reversed frozen elephant trunk to treat thoracoabdominal aortic aneurysms (TAAA) through an abdominal only approach. The technique is demonstrated in a 29-year-old Marfan patient with a chronic type B aortic dissection previously treated with a thoracic stent-graft who presented with a thoracoabdominal false lumen aneurysm. Through an open distal retroperitoneal approach to the abdominal aorta, a frozen elephant trunk graft was implanted over a super-stiff wire upside down with the stent-graft component in the thoracic aorta. Following deployment of the stent-graft proximally and preservation of renovisceral perfusion in a retrograde manner, the renovisceral vessels were sequentially anastomosed to the elephant trunk graft branches, thus reducing the ischemia time of the end organs. The aortic sac was then opened, and the distal part of the hybrid graft was anastomosed with a further bifurcated graft to the iliac vessels. The reversed frozen elephant trunk technique is feasible for hybrid treatment of TAAAs via an abdominal approach only. This has the benefit of substantially reducing the trauma of thoracic exposure, thus preserving major benefits of open thoracoabdominal surgery, such as the presence of short bypasses to the renovisceral vessels and reimplantation of lumbar arteries to reduce spinal cord ischemia.

Randomized multicenter study of multiple plastic stents vs. covered self-expandable metallic stent in the treatment of biliary stricture in chronic pancreatitis.

PubMed

Haapamäki, Carola; Kylänpää, Leena; Udd, Marianne; Lindström, Outi; Grönroos, Juha; Saarela, Arto; Mustonen, Harri; Halttunen, Jorma

2015-07-01

The use of covered self-expandable metallic stents (cSEMS) in benign biliary indications is evolving. The aim of the study was to assess the safety and feasibility of cSEMS compared with multiple plastic stents in the treatment of benign biliary stricture (BBS) caused by chronic pancreatitis. This was a prospective, multicenter, randomized study of 60 patients with BBS caused by chronic pancreatitis. All patients received an initial plastic stent before randomization. At randomization, the stent was replaced either with a single cSEMS or three plastic stents. After 3 months, the position of the cSEMS was checked or another three plastic stents were added. At 6 months after randomization, all stents were removed. Clinical follow-up including abdominal ultrasound and laboratory tests were performed at 6 months and 2 years after stent removal. Two patients dropped out of the cSEMS group before stent removal. In April 2014, the median follow-up was 40 months (range 1 - 66 months). The 2-year, stricture-free success rate was 90 % (95 % confidence interval [CI] 72 % - 97 %) in the plastic stent group and 92 % (95 %CI 70 % - 98 %) in the cSEMS group (P = 0.405). There was one late recurrence in the plastic stent group 50 months after stent removal. Stent migration occurred three times (10 %) in the plastic stent group and twice in the cSEMS group (7 %; P = 1.000). A 6-month treatment with either six 10-Fr plastic stents or with one 10-mm cSEMS produced good long-term relief of biliary stricture caused by chronic pancreatitis.Study registered at ClinicalTrials.gov (NCT01085747). © Georg Thieme Verlag KG Stuttgart · New York.

Antireflux Versus Conventional Plastic Stent in Malignant Biliary Obstruction: A Prospective Randomized Study.

PubMed

Vihervaara, Hanna; Grönroos, Juha M; Hurme, Saija; Gullichsen, Risto; Salminen, Paulina

2017-01-01

Endoscopic stents are used to relieve obstructive jaundice. The purpose of this prospective randomized study was to compare the patency of antireflux and conventional plastic biliary stent in relieving distal malignant biliary obstruction. All jaundiced patients admitted to hospital with suspected unresectable malignant distal biliary stricture between October 2009 and September 2010 were evaluated for the study. Eligible patients were randomized either to antireflux or conventional plastic stent arms. The primary endpoint was stent patency and the follow-up was continued either until the stent was occluded or until 6 months after the stent placement. At an interim analysis, antireflux stents (ARSs; n = 6) had a significantly shorter median patency of 34 (8-49) days compared with the conventional stent (n = 7) patency of 167 (38-214) days (P = .0003). Based on these results, the study was terminated due to ethical concerns. According to these results, the use of this ARS is not recommended.

Comparison of partially covered nitinol stents with partially covered stainless stents as a historical control in a multicenter study of distal malignant biliary obstruction: the WATCH study.

PubMed

Isayama, Hiroyuki; Mukai, Tsuyoshi; Itoi, Takao; Maetani, Iruru; Nakai, Yousuke; Kawakami, Hiroshi; Yasuda, Ichiro; Maguchi, Hiroyuki; Ryozawa, Shomei; Hanada, Keiji; Hasebe, Osamu; Ito, Kei; Kawamoto, Hirofumi; Mochizuki, Hitoshi; Igarashi, Yoshinori; Irisawa, Atsushi; Sasaki, Tamito; Togawa, Osamu; Hara, Taro; Kamada, Hideki; Toda, Nobuo; Kogure, Hirofumi

2012-07-01

Covered self-expandable metal stents (CSEMSs) were developed to prevent tumor ingrowth, but stent migration is one of the problems with CSEMSs. To evaluate a new, commercially available CSEMS with flared ends and low axial force compared with a commercially available CSEMS without the anti-migration system and high axial force. Multicenter, prospective study with a historical cohort. Twenty Japanese referral centers. This study involved patients with unresectable distal malignant biliary obstruction. Placement of a new, commercially available, partially covered SEMS. Recurrent biliary obstruction rate, time to recurrent biliary obstruction, stent-related complications, survival. Between April 2009 and March 2010, 141 patients underwent partially covered nitinol stent placement, and between May 2001 and January 2007, 138 patients underwent placement of partially covered stainless stents as a historical control. The silicone cover of the partially covered nitinol stents prevented tumor ingrowth. There were no significant differences in survival (229 vs 219 days; P = .250) or the rate of recurrent biliary obstruction (33% vs 38%; P = .385) between partially covered nitinol stents and partially covered stainless stents. Stent migration was less frequent (8% vs 17%; P = .019), and time to recurrent biliary obstruction was significantly longer (373 vs 285 days; P = .007) with partially covered nitinol stents. Stent removal was successful in 26 of 27 patients (96%). Nonrandomized, controlled trial. Partially covered nitinol stents with an anti-migration system and less axial force demonstrated longer time to recurrent biliary obstruction with no tumor ingrowth and less stent migration. Copyright © 2012 American Society for Gastrointestinal Endoscopy. Published by Mosby, Inc. All rights reserved.

A new partially covered metal stent for palliation of malignant dysphagia: a prospective follow-up study.

PubMed

van Boeckel, Petra G; Siersema, Peter D; Sturgess, Richard; Dwyer, Laura; Raijman, Isaac; Hirdes, Meike M; Vleggaar, Frank P

2010-12-01

Metal stents are frequently used for palliation of malignant dysphagia. Recently, a new stent design, the partially covered Wallflex stent (Boston Scientific, Natick, Mass), has been introduced. To determine clinical effectiveness and safety of the esophageal Wallflex stent for the palliation of dysphagia. A prospective follow-up study evaluating a new stent design. Three tertiary-care referral centers. This study involved 37 patients with cancer of the esophagus or gastric cardia. Stent placement. Data were collected regarding technical and clinical outcome, complications, recurrent dysphagia, and survival. A total of 37 patients (median age, 67 years; range, 48-84 years; 22 men [59%]) had a Wallflex stent placed. Stent placement was technically successful in all but 1 patient. Dysphagia improved from a median dysphagia score of 3 (ability to swallow liquids only) to 1 (ability to eat some solid foods) 4 weeks after stent placement. Major complications occurred in 3 patients (8%; pneumonia in 1, severe pain in 2), and 1 patient (3%) died from a complication (pneumonia). Minor complications included mild retrosternal pain in 10 patients (27%) and regurgitation in 7 patients (19%). In total, 8 patients (22%) developed recurrent dysphagia because of stent migration (n = 2 [6%]), food impaction (n = 2 [6%]), or tissue ingrowth or overgrowth (n = 4 [10%]). Nonrandomized study design. Placement of a partially covered Wallflex stent is safe and effective for the palliation of malignant dysphagia, with migration and tissue in- and overgrowth rates comparable to those of similarly designed stents. Retrosternal pain may occur more often with this stent than with other stent designs. Copyright © 2010 American Society for Gastrointestinal Endoscopy. Published by Mosby, Inc. All rights reserved.

Covered metal stent or multiple plastic stents for refractory pancreatic ductal strictures in chronic pancreatitis: a systematic review.

PubMed

Shen, Yonghua; Liu, Mingdong; Chen, Min; Li, Yunhong; Lu, Ying; Zou, Xiaoping

2014-01-01

Refractory chronic pancreatitis has been proposed as a challenge for endoscopists following routine single plastic stenting. However, data on the efficacy and safety of further endoscopic stenting are still controversial. The current systematic review aimed to assess the efficacy and safety of placement of fully covered self-expandable metal stent (FCSEMS) and multiple plastic stents. Databases including MEDLINE, EMBASE, the Cochrane Library, CBM, CNKI, VIP, and WANFANG Database were used to search relevant trials. Published studies were assessed by using well-defined inclusion and exclusion criteria. The process was independently performed by two investigators. A total of 5 studies provided data of 80 patients. Forest plots and publication bias were not carried out because few studies were relevant and screened studies were all case series. The technical success rate was 100% both in placement of FCSEMS and multiple plastic stents. The functional success rate after placement of FCSEMS was 100%, followed by multiple plastic stents (94.7%). Complications occurred 26.2% after FCSEMS placement, which was not described in detail in multiple plastic stents. The stent migration rate was 8.2% for FCSEMS and 10.5% for multiple plastic stents. Reintervention rate was 9.8% for FCSEMS and 15.8% for multiple plastic stents. Pain improvement rate was 85.2% for FCSEMS and 84.2% for multiple plastic stents. FCSEMS appeared to be no significant difference with multiple plastic stents in treatment of refractory chronic pancreatitis. We need to develop more investigations. Copyright © 2014 IAP and EPC. Published by Elsevier B.V. All rights reserved.

Optimization of stent implantation using a high pressure inflation protocol.

PubMed

Vallurupalli, Srikanth; Bahia, Amit; Ruiz-Rodriguez, Ernesto; Ahmed, Zubair; Hakeem, Abdul; Uretsky, Barry F

2016-01-01

High-pressure inflation is the universal standard for stent deployment but a specific protocol for its use is lacking. We developed a standardized "pressure optimization protocol" (POP) using time to inflation pressure stability as an endpoint for determining the required duration of stent inflation. The primary study purpose was to determine the stent inflation time (IT) in a large patient cohort using the standardized inflation protocol, to correlate various patient and lesion characteristics with IT, and ascertain in an in vitro study the time for pressure accommodation within an inflation system. Six hundred fifteen stent implants in 435 patients were studied. Multivariate analysis was performed to determine predictors of longer ITs. In an in vitro study, various stents and balloons were inflated in air to determine the pressure accommodation time of the inflation system. The mean stent IT was 104 ± 41 sec (range 30-380 sec). Stent length was the only predictor of prolonged stent inflation. The "accommodation time" in vitro of the stent inflation system itself was 33 ± 24 sec. The protocol was safe requiring premature inflation termination in <3% of stent implants. No serious adverse events occurred. Achieving stable inflation pressure requires on average over 100 sec and may require several minutes in individual cases. Stent length increases IT. These results suggest that the widespread practice of rapid inflation/deflation may not be sufficient to fully expand the stent and that the use of a pressure stability protocol will allow for safe, predictable, and more complete stent deployment. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

Plastic biliary stent patency in patients with locally advanced pancreatic adenocarcinoma receiving downstaging chemotherapy.

PubMed

Ge, Phillip S; Hamerski, Christopher M; Watson, Rabindra R; Komanduri, Srinadh; Cinnor, Birtukan B; Bidari, Kiran; Klapman, Jason B; Lin, Cui L; Shah, Janak N; Wani, Sachin; Donahue, Timothy R; Muthusamy, V Raman

2015-02-01

Plastic stents in patients with biliary obstruction caused by pancreatic adenocarcinoma are typically exchanged at 3-month intervals. Plastic stents may have reduced durability in patients receiving chemotherapy. To determine the duration of plastic biliary stent patency in patients undergoing chemotherapy for pancreatic adenocarcinoma. Retrospective, multicenter cohort study. Three tertiary academic referral centers. A total of 173 patients receiving downstaging chemotherapy for locally advanced or borderline resectable pancreatic adenocarcinoma from 1996 to 2013. Placement of 10F or larger plastic biliary stents. Primary outcome was overall duration of stent patency. Secondary outcomes included the incidence of premature stent exchange (because of cholangitis or jaundice) and hospitalization rates. A total of 233 plastic stents were placed, and the overall median duration of stent patency was 53 days (interquartile range [IQR] 25-99 days). Eighty-seven stents were removed at the time of surgical resection, and 63 stents were exchanged routinely per protocol. The remaining 83 stent exchanges were performed for worsening liver function test results, jaundice, or cholangitis, representing a 35.6% rate of premature stent exchange. The median stent patency duration in the premature stent exchange group was 49 days (IQR 25-91 days) with a 44.6% hospitalization rate. The overall rate of cholangitis was 15.0% of stent exchanges, occurring a median of 56 days after stent placement (IQR 26-89 days). Retrospective study. Plastic biliary stents placed during chemotherapy/chemoradiation for pancreatic adenocarcinoma have a shorter-than-expected patency duration, and a substantial number of patients will require premature stent exchange. Consideration should be given to shortening the interval for plastic biliary stent exchange. Copyright © 2015 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc. All rights reserved.

Effect of modification of oxide layer on NiTi stent corrosion resistance.

PubMed

Trépanier, C; Tabrizian, M; Yahia, L H; Bilodeau, L; Piron, D L

1998-01-01

Because of its good radiopacity, superelasticity, and shape memory properties, nickel-titanium (NiTi) is a potential material for fabrication of stents because these properties can facilitate their implantation and precise positioning. However, in vitro studies of NiTi alloys report the dependence of alloy biocompatibility and corrosion behavior on surface conditions. Surface oxidation seems to be very promising for improving the corrosion resistance and biocompatibility of NiTi. In this work, we studied the effect on corrosion resistance and surface characteristics of electropolishing, heat treatment, and nitric acid passivation of NiTi stents. Characterization techniques such as potentiodynamic polarization tests, scanning electron microscopy, Auger electron spectroscopy, and X-ray photoelectron spectroscopy were used to relate corrosion behavior to surface characteristics and surface treatments. Results show that all of these surface treatments improve the corrosion resistance of the alloy. This improvement is attributed to the plastically deformed native oxide layer removal and replacement by a newly grown, more uniform one. The uniformity of the oxide layer, rather than its thickness and composition, seems to be the predominant factor to explain the corrosion resistance improvement.

Computational Study of Intracranial Aneurysms with Flow Diverting Stent: Correlation with Surgical Outcome

NASA Astrophysics Data System (ADS)

Tang, Yik Sau; Chiu, Tin Lok; Tsang, Anderson Chun On; Leung, Gilberto Ka Kit; Chow, Kwok Wing

2016-11-01

Intracranial aneurysm, abnormal swelling of the cerebral artery, can cause massive internal bleeding in the subarachnoid space upon aneurysm rupture, leading to a high mortality rate. Deployment of a flow diverting stent through endovascular technique can obstruct the blood flow into the aneurysm, thus reducing the risk of rupture. Patient-specific models with both bifurcation and sidewall aneurysms have been investigated. Computational fluid dynamics analysis with physiological boundary conditions has been performed. Several hemodynamic parameters including volume flow rate into the aneurysm and the energy (sum of the fluid kinetic and potential energy) loss between the inlet and outlets were analyzed and compared with the surgical outcome. Based on the simulation results, we conjecture that a clinically successful case might imply less blood flow into the aneurysm after stenting, and thus a smaller amount of energy loss in driving the fluid flow in that portion of artery. This study might provide physicians with quantitative information for surgical decision making. (Partial financial support by the Innovation and Technology Support Program (ITS/011/13 & ITS/150/15) of the Hong Kong Special Administrative Region Government)

Plastic strains during stent deployment have a critical influence on the rate of corrosion in absorbable magnesium stents.

PubMed

Galvin, Emmet; Cummins, Christy; Yoshihara, Shoichiro; Mac Donald, Bryan J; Lally, Caitríona

2017-08-01

Magnesium stents are a promising candidate in the emerging field of absorbable metallic stents (AMSs). In this study, the mechanical and corrosion performance of dog-bone specimens and a specific stent design of a magnesium alloy, WE43, are assessed experimentally in terms of their corrosion behaviour and mechanical integrity. It is shown that plastic strains that are induced in the struts of the stent during stent deployment have a critical influence in directing subsequent corrosion behaviour within the material. In addition, the deployment and scaffolding characteristics of the magnesium stent are elucidated and contrasted with those of a commercial stainless steel stent. The magnesium stent is found to support higher levels of cyclic strain amplitude than the stainless steel stent, even prior to degradation, and this may play a role in reducing in-stent restenosis. This study provides new insights into the experimental performance of a current AMS design and material whilst demonstrating the critical influence of plastic strain on the corrosion performance and scaffolding ability of an AMS.

Molecular intravascular imaging approaches for atherosclerosis.

PubMed

Press, Marcella Calfon; Jaffer, Farouc A

2014-10-01

Coronary artery disease (CAD) is an inflammatory process that results in buildup of atherosclerosis, typically lipid-rich plaque in the arterial wall. Progressive narrowing of the vessel wall and subsequent plaque rupture can lead to myocardial infarction and death. Recent advances in intravascular fluorescence imaging techniques have provided exciting coronary artery-targeted platforms to further characterize the molecular changes that occur within the vascular wall as a result of atherosclerosis and following coronary stent-induced vascular injury. This review will summarize exciting recent developments in catheter-based imaging of coronary arterial-sized vessels; focusing on two-dimensional near-infrared fluorescence imaging (NIRF) molecular imaging technology as an approach to specifically identify inflammation and fibrin directly within coronary artery-sized vessels. Intravascular NIRF is anticipated to provide new insights into the in vivo biology underlying high-risk plaques, as well as high-risks stents prone to stent restenosis or stent thrombosis.

Endoscopic management of hilar biliary strictures

PubMed Central

Singh, Rajiv Ranjan; Singh, Virendra

2015-01-01

Hilar biliary strictures are caused by various benign and malignant conditions. It is difficult to differentiate benign and malignant strictures. Postcholecystectomy benign biliary strictures are frequently encountered. Endoscopic management of these strictures is challenging. An endoscopic method has been advocated that involves placement of increasing number of stents at regular intervals to resolve the stricture. Malignant hilar strictures are mostly unresectable at the time of diagnosis and only palliation is possible.Endoscopic palliation is preferred over surgery or radiological intervention. Magnetic resonance cholangiopancreaticography is quite important in the management of these strictures. Metal stents are superior to plastic stents. The opinion is divided over the issue of unilateral or bilateral stenting.Minimal contrast or no contrast technique has been advocated during endoscopic retrograde cholangiopancreatography of these patients. The role of intraluminal brachytherapy, intraductal ablation devices, photodynamic therapy, and endoscopic ultrasound still remains to be defined. PMID:26191345

New dedicated bifurcated silicone stent placement for stenosis around the primary right carina.

PubMed

Oki, Masahide; Saka, Hideo

2013-08-01

Silicone stenting has been widely used to palliate respiratory symptoms in patients suffering from airway stenosis. Although many types and shapes of stents have been developed, there is no ideal stent for stenosis around the carina between the bronchus to the right upper lobe and the bronchus intermedius (primary right carina). The purpose of this study was to evaluate the feasibility, efficacy, and safety of a new silicone stent designed for treating airway stenosis around the primary right carina. We recruited 16 patients with suspected stenosis around the primary right carina. Ten of the patients met the inclusion criteria for inserting the study stent. All stenting procedures were performed with a rigid and flexible bronchoscope under general anesthesia. The study stent could be mounted successfully on the primary right carina in all 10 patients. Five patients underwent stenting using only the new stent, and the other five underwent stenting with it on the primary right carina and a silicone Y stent on the main carina. The dyspnea index improved in eight of the 10 patients, including one who was mechanically ventilated. Early complications developed in three patients (temporary pneumonia in two and retention of secretions in one), and late complications occurred in two patients (granuloma formation in one and hemoptysis in one). Stent placement with the new silicone stent designed to fit on the primary right carina is feasible, effective, and acceptably safe. UMIN-Clinical Trials Registry; No.: UMIN000001776; URL: www.umin.ac.jp/ctr.

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.

Metallic ureteral stents in malignant ureteral obstruction: clinical factors predicting stent failure.

PubMed

Chow, Po-Ming; Hsu, Jui-Shan; Huang, Chao-Yuan; Wang, Shuo-Meng; Lee, Yuan-Ju; Huang, Kuo-How; Yu, Hong-Jheng; Pu, Yeong-Shiau; Liang, Po-Chin

2014-06-01

To provide clinical outcomes of the Resonance metallic ureteral stent in patients with malignant ureteral obstruction, as well as clinical factors predicting stent failure. Cancer patients who have received Resonance stents from July 2009 to March 2012 for ureteral obstruction were included for chart review. Stent failure was detected by clinical symptoms, image studies, and renal function tests. Survival analysis for stent duration was used to estimate patency rate and factors predicting stent failure. A total of 117 stents were inserted successfully into 94 ureteral units in 79 patients. There were no major complications. These stents underwent survival analysis and proportional hazard regression. The median duration for the stents was 5.77 months. In multivariate analysis, age (P=0.043), preoperative serum creatinine level (P=0.0174), and cancer type (P=0.0494) were significant factors associated with stent failure. Cancer treatment before and after stent insertion had no effect on stent duration. Resonance stents are effective and safe in relieving malignant ureteral obstructions. Old age and high serum creatinine level are predictors for stent failure. Stents in patients with lower gastrointestinal cancers have longer functional duration.

Novel Biliary Reconstruction Techniques During Liver Transplantation

PubMed Central

Carmody, Ian C.; Romano, John; Bohorquez, Humberto; Bugeaud, Emily; Bruce, David S.; Cohen, Ari J.; Seal, John; Reichman, Trevor W.; Loss, George E.

2017-01-01

Background: Biliary complications remain a significant problem following liver transplantation. Several surgical options can be used to deal with a significant size mismatch between the donor and recipient bile ducts during the biliary anastomosis. We compared biliary transposition to recipient biliary ductoplasty in cadaveric liver transplant. Methods: A total of 33 reconstructions were performed from January 1, 2005 to December 31, 2013. In the biliary transposition group (n=23), 5 reconstructions were performed using an internal stent (5 or 8 French pediatric feeding tube), and 18 were performed without. Of the 10 biliary ductoplasties, 2 were performed with a stent. All patients were managed with standard immunosuppression and ursodiol. Follow-up ranged from 2 months to 5 years. Results: No patients in the biliary transposition group required reoperation; 1 patient had an internal stent removed for recurrent unexplained leukocytosis, and 2 patients required endoscopic retrograde cholangiography and stent placement for evidence of stricture. Three anastomotic leaks occurred in the biliary ductoplasty group, and 2 patients in the biliary ductoplasty group required reoperation for biliary complications. Conclusion: Our results indicate that biliary reconstruction can be performed with either biliary transposition or biliary ductoplasty. These techniques are particularly useful when a significant mismatch in diameter exists between the donor and recipient bile ducts. PMID:28331447

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.

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.

Heparin surface stent-graft for the treatment of a carotid pseudoaneurysm.

PubMed

Tsolaki, Elpiniki; Elpiniki, Tsolaki; Salviato, Elisabetta; Rocca, Tiberio; Braccini, Lucia; Galeotti, Roberto; Mascoli, Francesco

2010-10-01

Carotid pseudoaneurysms are a rare consequence of carotid surgery, trauma, and infection. Historically, carotid aneurysms and pseudoaneurysms were treated surgically. However, endovascular techniques have recently become a valid alternative for the treatment of carotid pseudoaneurysms. The case of a 57-year-old male patient with a pseudoaneurysm of the right internal carotid artery is described. The patient came to our unit with a painless and pulsatile mass in the neck, which was growing slowly. Five years earlier, he had undergone surgery on a saccular aneurysm located on the distal extracranial segment of the right internal carotid artery. The pseudoaneurysm was successfully treated with a heparin surface Viabahn stent-graft system (Gore AL, Flagstaff, AZ). Heparin surface stent-grafts can be used for the treatment of carotid lesions and may offer protection against intimal hyperplasia and thrombosis. Further studies are needed to evaluate the long-term results. Copyright © 2010 Annals of Vascular Surgery Inc. Published by Elsevier Inc. All rights reserved.

Efficacy and tolerance of a new silicone stent for the treatment of benign tracheal stenosis: preliminary results.

PubMed

Vergnon, J M; Costes, F; Polio, J C

2000-08-01

In inoperable patients with tracheal stenosis who are treated using silicone stents, stent migration occurs in 18.6% of cases. To decrease the migration rate, we have designed a new silicone stent with narrow central and larger distal parts. This study analyzes the stability and tolerance of this new stent. Preliminary prospective study conducted in two French university hospitals. Thirteen inoperable patients with benign complex tracheal stenosis due to intubation or tracheotomy. Tracheal stent insertion was performed under general anesthesia with a rigid bronchoscope. The patients were followed up clinically up to stent removal, which was planned at 18 months. Stent insertion or removal was very simple and did not differ from other silicone stents. No migration occurred after a mean follow-up of 22.8 months. Minimal granuloma formation occurred in only one patient (7.7%). Sputum retention remained similar to that with other silicone stents and could be improved by a smoother internal wall. Stents have been removed in seven patients after a mean duration of 19.6 months, with a complete stenosis cure in four cases. This new stent combines the excellent stability of the metallic stents and the tolerance and easy removal of straight silicone stents. This allows a prolonged use in order to obtain curative action.

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

Gandini, Roberto; Fabiano, S., E-mail: sebas575@yahoo.it; Pipitone, Vincenzo

The efficacy of the 'one-step' technique using two different metallic stents (Wallstent and Ultraflex) and associated rate of complications was studied in 87 patients with jaundice secondary to malignant biliary obstruction, with bilirubin level less than 15 mg/dl and Bismuth type 1 or 2 strictures. The study group, composed of 40 men and 47 women with a mean age of 59.4 years (range 37-81 years), was treated with a 'one-step' percutaneous transhepatic implantation of self-expanding stents. The cause of the obstruction was pancreatic carcinoma in 38 patients (44%), lymph node metastasis in 20 patients (23%), gallbladder carcinoma in 13 patientsmore » (15%), cholangiocarcinoma in 12 patients (14%) and ampullary carcinoma in four patients (5%). A significant reduction in jaundice was obtained in all but one patient, with a drop of total serum bilirubin level from a mean of 13.7 mg/dl to 4.3 mg/dl within the first 4 days. The mean postprocedural hospitalization period was 5.4 days in the Wallstent group and 6.4 days in the Ultraflex group. Mean survival rate was 7.8 months (Wallstent group) and 7.1 months (Ultraflex group). The use of both stents did not reveal any significant difference in parameters tested. The implantation of these self-expandable stents in one session, in selected patients, is clinically effective, devoid of important complications and cost-effective due to the reduction in hospitalization.« less

Development and Initial Porcine and Cadaver Experience with Three-Dimensional Printing of Endoscopic and Laparoscopic Equipment

PubMed Central

del Junco, Michael; Okhunov, Zhamshid; Yoon, Renai; Khanipour, Ramtin; Juncal, Samuel; Abedi, Garen; Lusch, Achim

2015-01-01

Abstract Introduction: Recent advances in three-dimensional (3D) printing technology have made it possible to print surgical devices. We report our initial experience with the printing and deployment of endoscopic and laparoscopic equipment. Materials and Methods: We created computer-aided designs for ureteral stents and laparoscopic trocars using SolidWorks. We developed three generations of stents, which were printed with an Objet500 Connex printer, and a fourth generation was printed with an EOSINT P395 printer. The trocars were printed with an Objet30 Pro printer. We deployed the printed stents and trocars in a female cadaver and in vivo porcine model. We compared the printed trocars to two standard trocars for defect area and length using a digital caliper. Paired T-tests and ANOVA were used to test for statistical difference. Results: The first two generations of stents (7F and 9F) were functional failures as their diminutive inner lumen failed to allow the passage of a 0.035 guidewire. The third generation 12F stent allowed passage of a 0.035 guidewire. The 12F diameter limited its deployment, but it was introduced in a cadaver through a ureteral access sheath. The fourth-generation 9F stents were printed and deployed in a porcine model using the standard Seldinger technique. The printed trocars were functional for the maintenance of the pneumoperitoneum and instrument passage. The printed trocars had larger superficial defect areas (p<0.001) and lengths (p=0.001) compared to Karl Storz and Ethicon trocars (29.41, 18.06, and 17.22 mm2, respectively, and 14.29, 11.39, and 12.15 mm, respectively). Conclusions: In this pilot study, 3D printing of ureteral stents and trocars is feasible, and these devices can be deployed in the porcine and cadaver models. Three-dimensional printing is rapidly advancing and may be clinically viable in the future. PMID:24983138

Clinical outcomes with the STENTYS self-apposing coronary stent in patients presenting with ST-segment elevation myocardial infarction: two-year insights from the APPOSITION III (A Post-Market registry to assess the STENTYS self-exPanding COronary Stent In AcuTe MyocardIal InfarctiON) registry.

PubMed

Lu, Huangling; Grundeken, Maik J; Vos, Nicola S; IJsselmuiden, Alexander J J; van Geuns, Robert-Jan; Wessely, Rainer; Dengler, Thomas; La Manna, Alessio; Silvain, Johanne; Montalescot, Gilles; Spaargaren, René; Tijssen, Jan G P; Amoroso, Giovanni; de Winter, Robbert J; Koch, Karel T

2017-08-04

The APPOSITION III registry evaluated the feasibility and performance of the STENTYS self-apposing stent in an ST-segment elevation myocardial infarction (STEMI) population. This novel self-apposing stent device lowers stent strut malapposition rates and therefore carries the potential to prevent stent undersizing during primary percutaneous coronary intervention (PCI) in STEMI patients. To date, no long-term data are available using this device in the setting of STEMI. We aimed to evaluate the long-term clinical outcomes of the APPOSITION III registry. This was an international, prospective, multicentre post-marketing registry. The study population consisted of 965 STEMI patients. The primary endpoint, major adverse cardiac events (MACE), was defined as the composite of cardiac death, recurrent target vessel myocardial infarction (TV-MI), and clinically driven target lesion revascularisation (CD-TLR). At two years, MACE occurred in 11.2%, cardiac death occurred in 2.3%, TV-MI occurred in 2.3% and CD-TLR in 9.2% of patients. The two-year definite stent thrombosis (ST) rate was 3.3%. Incremental event rates between one- and two-year follow-up were 1.0% for TV-MI, 1.8% for CD-TLR, and 0.5% for definite ST. Post-dilation resulted in significantly reduced CD-TLR and ST rates at 30-day landmark analyses. Results were equivalent between the BMS and PES STENTYS subgroups. This registry revealed low rates of adverse events at two-year follow-up, with an incremental ST rate as low as 0.5% in the second year, demonstrating that the self-apposing technique is feasible in STEMI patients on long-term follow-up while using post-dilatation.

Development and initial porcine and cadaver experience with three-dimensional printing of endoscopic and laparoscopic equipment.

PubMed

del Junco, Michael; Okhunov, Zhamshid; Yoon, Renai; Khanipour, Ramtin; Juncal, Samuel; Abedi, Garen; Lusch, Achim; Landman, Jaime

2015-01-01

Recent advances in three-dimensional (3D) printing technology have made it possible to print surgical devices. We report our initial experience with the printing and deployment of endoscopic and laparoscopic equipment. We created computer-aided designs for ureteral stents and laparoscopic trocars using SolidWorks. We developed three generations of stents, which were printed with an Objet500 Connex printer, and a fourth generation was printed with an EOSINT P395 printer. The trocars were printed with an Objet30 Pro printer. We deployed the printed stents and trocars in a female cadaver and in vivo porcine model. We compared the printed trocars to two standard trocars for defect area and length using a digital caliper. Paired T-tests and ANOVA were used to test for statistical difference. The first two generations of stents (7F and 9F) were functional failures as their diminutive inner lumen failed to allow the passage of a 0.035 guidewire. The third generation 12F stent allowed passage of a 0.035 guidewire. The 12F diameter limited its deployment, but it was introduced in a cadaver through a ureteral access sheath. The fourth-generation 9F stents were printed and deployed in a porcine model using the standard Seldinger technique. The printed trocars were functional for the maintenance of the pneumoperitoneum and instrument passage. The printed trocars had larger superficial defect areas (p<0.001) and lengths (p=0.001) compared to Karl Storz and Ethicon trocars (29.41, 18.06, and 17.22 mm(2), respectively, and 14.29, 11.39, and 12.15 mm, respectively). In this pilot study, 3D printing of ureteral stents and trocars is feasible, and these devices can be deployed in the porcine and cadaver models. Three-dimensional printing is rapidly advancing and may be clinically viable in the future.

Metallic Limus-Eluting Stents Abluminally Coated with Biodegradable Polymers: Angiographic and Clinical Comparison of a Novel Ultra-Thin Sirolimus Stent Versus Biolimus Stent in the DESTINY Randomized Trial.

PubMed

Lemos, Pedro A; Abizaid, Alexandre A C; Meireles, George C; Sarmento-Leite, Rogério; Prudente, Mauricio; Cantarelli, Marcelo; Dourado, Adriano D; Mariani, Jose; Perin, Marco A; Costantini, Costantino; Costa, Ricardo A; Costa, José Ribamar; Chamie, Daniel; Campos, Carlos A; Ribeiro, Expedito

2015-12-01

To evaluate the outcomes of patients treated with a new drug-eluting stent formulation with low doses of sirolimus, built in an ultra-thin-strut platform coated with biodegradable abluminal coating. This study is a randomized trial that tested the main hypothesis that the angiographic late lumen loss of the novel sirolimus-eluting stent is noninferior compared with commercially available biolimus-eluting stent. A final study population comprising 170 patients with one or two de novo lesions was randomized in the ratio 2:1 for sirolimus-eluting stent or biolimus-eluting stent, respectively. The primary endpoint was 9-month angiographic in-stent late lumen loss. Adverse clinical events were prospectively collected for 1 year. After 9 months, the novel sirolimus-eluting stent was shown noninferior compared with the biolimus stent for the primary endpoint (angiographic in-stent late lumen loss: 0.20 ± 0.29 mm vs. 0.15 ± 0.20 mm, respectively; P value for noninferiority <0.001). The 1-year incidence of death, myocardial infarction, repeat revascularization, and stent thrombosis remained low and not significantly different between the groups. The present randomized trial demonstrates that the tested novel sirolimus-eluting stent was angiographically noninferior in comparison with a last-generation biolimus-eluting stent. © 2015 John Wiley & Sons Ltd.

Timing of silicone stent removal in patients with post-tuberculosis bronchial stenosis.

PubMed

Eom, Jung Seop; Kim, Hojoong; Park, Hye Yun; Jeon, Kyeongman; Um, Sang-Won; Koh, Won-Jung; Suh, Gee Young; Chung, Man Pyo; Kwon, O Jung

2013-10-01

In patients with post-tuberculosis bronchial stenosis (PTBS), the severity of bronchial stenosis affects the restenosis rate after the silicone stent is removed. In PTBS patients with incomplete bronchial obstruction, who had a favorable prognosis, the timing of stent removal to ensure airway patency is not clear. We evaluated the time for silicone stent removal in patients with incomplete PTBS. A retrospective study examined PTBS patients who underwent stenting and removal of a silicone stent. Incomplete bronchial stenosis was defined as PTBS other than total bronchial obstruction, which had a luminal opening at the stenotic segment on bronchoscopic intervention. The duration of stenting was defined as the interval from stent insertion to removal. The study included 44 PTBS patients and the patients were grouped at intervals of 6 months according to the duration of stenting. Patients stented for more than 12 months had a significantly lower restenosis rate than those stented for less than 12 months (4% vs. 35%, P = 0.009). Multiple logistic regression revealed an association between stenting for more than 12 months and a low restenosis rate (odds ratio 12.095; 95% confidence interval 1.097-133.377). Moreover, no restenosis was observed in PTBS patients when the stent was placed more than 14 months previously. In patients with incomplete PTBS, stent placement for longer than 12 months reduced restenosis after stent removal.

Hybrid treatment of tandem, common carotid/innominate artery and ipsilateral carotid bifurcation stenoses by simultaneous, retrograde proximal stenting and eversion carotid endarterectomy: Preliminary results of a case series.

PubMed

Illuminati, Giulio; Pizzardi, Giulia; Pasqua, Rocco; Frezzotti, Francesca; Palumbo, Piergaspare; Macrina, Francesco; Calio', Francesco

2018-04-01

Tandem stenoses of the internal carotid artery (ICA) and proximal, ipsilateral common carotid artery (CCA) or innominate artery can be treated with a hybrid approach, combining conventional carotid endarterectomy (CEA) and retrograde stenting of the proximal stenosis, through surgical exposure of the carotid bifurcation. The purpose of this study was to evaluate the results of combining eversion CEA with retrograde CCA/innominate artery stenting. From January 2015 to July 2017, 7 patients, 6 men of a mean age of 72 years (range 59-83 years) underwent simultaneous, retrograde stenting of the proximal CCA/innominate artery and an eversion CEA of the ipsilateral ICA, through surgical exposure of the carotid bifurcation, for severe tandem stenoses. The proximal stenosis involved the left proximal CCA in 4 patients, the proximal innominate artery in 2 patients and the right CCA in one patient. The procedure was performed under general anesthesia in a conventional operating room equipped with a mobile C-arm. A covered, balloon expandable stent was deployed over the proximal stenosis via a 6-F sheath directly introduced into the proximal CCA through the obliquely transected carotid bulb. After removing the sheath, debris were flushed through the carotid bulb and eversion CEA completed the procedure. Study endpoints were: postoperative stroke/mortality rate, cardiac mortality and morbidity, peripheral nerve injury, cervical hematoma, overall late survival, freedom from ipsilateral stroke and patency of arterial reconstruction. No postoperative mortality or neurologic morbidity was observed in any patient. Cervical hematomas and peripheral nerve injuries were likewise absent. At a mean follow-up of 18 months, all the patients were alive, free from neurologic events of new onset and free from restenosis. Combined proximal stenting and eversion CEA for tandem lesions seems a valid treatment, with the advantages of eversion CEA over other techniques of carotid bifurcation revascularization. Copyright © 2018 IJS Publishing Group Ltd. Published by Elsevier Ltd. All rights reserved.

A prospective, randomized study of the patency period of the plastic antireflux biliary stent: an interim analysis.

PubMed

Leong, Quan Wai; Shen, Mira L; Au, Kim W; Luo, Derek; Lau, James Y; Wu, Justin C; Chan, Francis K; Sung, Joseph J

2016-02-01

There is as yet no ideal design of a plastic biliary stent with the longest patency period. To study the safety and effective patency period of a new plastic antireflux biliary stent in the clinical setting. We conducted a prospective, randomized trial to compare the patency of 2 similar plastic biliary stents, one of which has an antiduodenobiliary reflux property. The study was conducted at 2 separate tertiary centers in 2 countries. Patients with inoperable distal malignant biliary obstruction were recruited. One of the 2 types of plastic stents under study was randomly chosen and inserted in the common bile duct of the study subjects. The subjects were followed until the end of study or occlusion occurrence. Our primary endpoint was the time to stent occlusion in days, with stent-related adverse events and all-cause mortality the secondary endpoints. A total of 16 subjects were recruited for the study; 7 were allocated to group A (ordinary Tannenbaum stent) and 9 to group B (antireflux biliary stent). Five of 7 subjects (71%) in group B had stent occlusion within 8 days, and the primary end point was reached in all 7 subjects within 30 days, whereas the primary endpoint was not reached within 30 days in any of the subjects in group A. Our data showed a significantly shorter stent patency period in group B compared with group A (P < .003). Small sample size. Routine use of antireflux plastic biliary stents in the palliative management of malignant biliary obstructions cannot be recommended at present. (Clinical trial registration number: NCT01142921.). Copyright © 2016 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc. All rights reserved.

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

Development of asymmetric stent for treatment of eccentric plaque.

PubMed

Syaifudin, Achmad; Takeda, Ryo; Sasaki, Katsuhiko

2018-01-01

The selection of stent and balloon type is decisive in the stenting process. In the treatment of an eccentric plaque obstruction, a symmetric expansion from stent dilatation generates nonuniform stress distribution, which may aggravate fibrous cap prone to rupture. This paper developed a new stent design to treat eccentric plaque using structural transient dynamic analysis in ANSYS. A non-symmetric structural geometry of stent is generated to obtain reasonable stress distribution safe for the arterial layer surrounding the stent. To derive the novel structural geometry, a Sinusoidal stent type is modified by varying struts length and width, adding bridges, and varying curvature width of struts. An end ring of stent struts was also modified to eliminate dogboning phenomenon and to reduce the Ectropion angle. Two balloon types were used to deploy the stent, an ordinary cylindrical and offset balloon. Positive modification results were used to construct the final non-symmetric stent design, called an Asymmetric stent. Analyses of the deformation characteristics, changes in surface roughness and induced stresses within intact arterial layer were subsequently examined. Interaction between the stent and vessel wall was implemented by means of changes in surface roughness and stress distribution analyses. The Palmaz and the Sinusoidal stent were used for a comparative study. This study indicated that the Asymmetric stent types reduced the central radial recoiling and the dogboning phenomenon. In terms of changes in surface roughness and induced stresses, the Asymmetric stent has a comparable effect with that of the Sinusoidal stent. In addition, it could enhance the distribution of surface roughening as expanded by an offset balloon.

Primary and revision efficacy of cross-wired metallic stents for endoscopic bilateral stent-in-stent placement in malignant hilar biliary strictures.

PubMed

Lee, T H; Moon, J H; Kim, J H; Park, D H; Lee, S S; Choi, H J; Cho, Y D; Park, S H; Kim, S J

2013-01-01

Endoscopic bilateral drainage for inoperable malignant hilar biliary strictures (HBS) using metal stents is considered to be technically difficult. Furthermore, endoscopic revision of bilateral stenting after occlusion can be challenging. This study was performed to evaluate the long-term efficacy of endoscopic bilateral stent-in-stent placement of cross-wired metallic stents in high-grade malignant HBS and planned endoscopic bilateral revision. A total of 84 patients with inoperable high-grade malignant HBS were enrolled from three academic tertiary referral centers. Two cross-wired metal stents were inserted using a bilateral stent-in-stent placement method. Bilateral endoscopic revision was also performed during follow-up using either identical metal stents or plastic stents. The main outcome measurements were technical and functional success, complications, stent patency, and endoscopic revision efficacy. The technical and clinical success rates of endoscopic bilateral stent-in-stent placement of cross-wired metallic stents were 95.2% (80/84) and 92.9% (78/84), respectively. Median patency (range) and survival were 238 days (10-429) and 256 days (10-1130), respectively. Obstruction of primary bilateral stents occurred in 30.8% (24/78) of patients with functionally successful stent placement. The technical and clinical success rates of planned bilateral endoscopic revision for occluded stents were 83.3% (20/24) and 79.2% (19/24), respectively. For revision, bilateral metallic stents were placed in 11 patients (55.0%); the remaining patients received plastic stents. Palliative endoscopic bilateral stent-in-stent placement of cross-wired metallic stents was effective in patients with inoperable HBS. Revision endoscopic bilateral stenting may be feasible and successful in cases where the primary deployed metal stents are occluded. © Georg Thieme Verlag KG Stuttgart · New York.

The insertion of self expanding metal stents with flexible bronchoscopy under sedation for malignant tracheobronchial stenosis: a single-center retrospective analysis.

PubMed

McGrath, Emmet E; Warriner, David; Anderson, Paul

2012-02-01

To describe a 10-year experience of inserting Ultraflex™ self-expanding metal stents (SEMS) under sedation using flexible bronchoscopy for the treatment of malignant tracheobronchial stenosis in a tertiary referral centre. Medical notes were retrospectively reviewed for all patients who underwent SEMS insertion between 1999 and 2009. A data analysis of 68 patients who had Ultraflex™ SEMS inserted under sedation was completed. Thirty three males and 35 females with a mean age of 67.9 years (range 35-94) presented with features including dyspnea/respiratory distress (39 patients), stridor (16 patients) and hemoptysis/dyspnea (13 patients). Etiology of stenosis included lung cancer (46 patients) esophageal cancer (14 patients) and other malignancies (8 patients). Mean dose of midazolam administered was 5mg (range 0-10mg). The trachea was the most common site of stent insertion followed by the right and left main bronchus, respectively. Adjuvant laser therapy was applied at some stage in 31% of all cases, and chemotherapy and/or radiotherapy was administered to at least 64% of patients with malignant disease. Hemoptysis and stent migration were the most frequent complications (5 and 4 patients, respectively). The mean survival time of stented non-small cell lung cancer (NSCLC) patients was 214 days (range 5-1233) and that of esophageal malignancy was 70 days (range 12-249). Mean pack-year history of individuals with lung cancer requiring stent insertion was 37 (range 2-100). Ultraflex stents offer a safe and effective therapy for patients who are inoperable or unresectable that otherwise would have no alternative therapy. It has an immediate beneficial effect upon patients, not only through symptom relief but, in some, through prolongation of life. Survival data is no worse than other studies using different varieties of stents and insertion techniques indicating its longer-term efficacy. Moreover, this report highlights the feasibility of performing this procedure successfully in a respiratory unit, without the need for general anesthesia. Copyright © 2011 SEPAR. Published by Elsevier Espana. All rights reserved.

The added benefits and efficacy of atherectomy in the lower limb.

PubMed

VAN DEN Berg, Jos C

2016-08-01

Atherectomy has been used as an adjunct therapy for balloon angioplasty and/or stent placement in the superficial femoral artery for many years, but has never gained global popularity in the treatment of peripheral arterial disease, most probably related to the conflicting results as published in the literature. Novel techniques that have been developed over the past years are yielding promising results in the infrainguinal region. This paper will describe the added benefits of atherectomy as compared to plain old balloon angioplasty and bail-out bare-metal stenting, both in the treatment of primary lesions of the superficial femoral artery as well as in cases of in-stent restenosis.

Metallic stents in the management of ureteric strictures

PubMed Central

Kulkarni, Ravi

2014-01-01

Management of ureteric strictures is a challenging task. Subtle presentation, silent progression and complex aetiology may delay diagnosis. A wide range of available treatment options combined with the lack of adequate randomised trials has led to the introduction of personal bias in the management of this difficult group of patients. Metallic ureteric stents offer an alternative to the conventional treatment modalities. A review of the currently available metallic stents and their role in the long-term management of ureteric strictures is presented. Materials used in the manufacture of indwelling urological devices are evolving all the time. Improved endo-urological techniques combined with new devices made from better compounds will continue to improve patient experience. PMID:24497686

Carotid Artery Stenting

PubMed Central

2018-01-01

Carotid artery stenosis is relatively common and is a significant cause of ischemic stroke, but carotid revascularization can reduce the risk of ischemic stroke in patients with significant symptomatic stenosis. Carotid endarterectomy has been and remains the gold standard treatment to reduce the risk of carotid artery stenosis. Carotid artery stenting (CAS) (or carotid artery stent implantation) is another method of carotid revascularization, which has developed rapidly over the last 30 years. To date, the frequency of use of CAS is increasing, and clinical outcomes are improving with technical advancements. However, the value of CAS remains unclear in patients with significant carotid artery stenosis. This review article discusses the basic concepts and procedural techniques involved in CAS. PMID:29171201

Rare Esophageal Migration of AXIOS Stent Used for Walled-off Pancreatic Necrosis Drainage

PubMed Central

Renno, Anas; Hammad, Tariq; Nawras, Ali

2017-01-01

The AXIOS stent (Boston Scientific, Marlborough, MA) is a novel lumen-apposing self-expandable metallic stent designed for enteric drainage of nonadherent lumens. Efficacy and safety of using the AXIOS stent for pancreatic fluid drainage have been consistently shown in several studies. Although it is less common with this novel stent, stent migration still may happen. We present a case of AXIOS stent migration into the esophagus. PMID:28584846

Role of Esophageal Metal Stents Placement and Combination Therapy in Inoperable Esophageal Carcinoma: A Systematic Review and Meta-analysis.

PubMed

Lai, Andrew; Lipka, Seth; Kumar, Ambuj; Sethi, Sajiv; Bromberg, David; Li, Nanxing; Shen, Huafeng; Stefaniwsky, Lilia; Brady, Patrick

2018-04-01

More than 50% of patients with esophageal cancer already have inoperable disease at the time of diagnosis. Controversy surrounds the outcomes of patients with advanced esophageal cancer who receive palliative care by either stent alone or stent plus an additional modality. We set out to perform a systematic review and meta-analysis of studies assessing the use of metal stents as treatment options for symptomatic improvement, survival, and adverse events. We searched Embase, MEDLINE, and the Cochrane Central Register of Controlled Trials (CENTRAL) from inception until January 14, 2016, as well as other databases for randomized controlled trials (RCTs) comparing esophageal stent versus either esophageal stent plus brachytherapy, radiotherapy, or chemotherapy. For quality assurance purposes throughout the systematic review, multiple independent extractions were performed, and the process was executed as per the standards of the Cochrane collaboration. Primary outcomes were mean change in dysphagia score, overall survival, and quality of life. Secondary outcomes were adverse events including fever, severe pain, aspiration, fistula, stent migration, perforation, and restenosis. Eight RCTs enrolling 732 patients were included with three distinct comparisons: stents combination therapy vs stents alone (5 studies, n = 417), stents alone versus brachytherapy alone (2 studies, n = 274), and stents + brachytherapy vs brachytherapy alone (1 study, n = 41). Stents combination therapy was defined as stents plus radiotherapy, chemotherapy, or both. Mean change in dysphagia scores favored stents combination therapy versus stents alone, and the effect was seen in patients surviving longer than 3 months. Stents combination therapy was also associated with a more favorable overall survival. The risks of stent migration, aspiration pneumonia, and restenosis were lower in the stents combination group compared to stents alone, while the risks of severe pain, hemorrhage, and fistula formation were higher. Changes in dysphagia scores and overall survival did not differ significantly in the brachytherapy-alone vs stents-alone comparison. The risk of fistula formation and hemorrhage were higher in the stents-alone group, while the risk of perforation was lower, compared to brachytherapy alone. Quality of life improvements were seen in all treatment groups, but were not pooled in analysis due to differing methods of measurement. While there appears to be no immediate short-term differences, those who live longer than 3 months experience a significant improvement in dysphagia score using a stents combination therapy approach vs stents alone. The combination therapy significantly improves the overall survival as well as showed improvements in quality of life scores. Larger randomized controlled trials are needed to assess improvements in dysphagia score, overall survival, quality of life, and adverse events.

Radial force measurement of endovascular stents: Influence of stent design and diameter.

PubMed

Matsumoto, Takuya; Matsubara, Yutaka; Aoyagi, Yukihiko; Matsuda, Daisuke; Okadome, Jun; Morisaki, Koichi; Inoue, Kentarou; Tanaka, Shinichi; Ohkusa, Tomoko; Maehara, Yoshihiko

2016-04-01

Angioplasty and endovascular stent placement is used in case to rescue the coverage of main branches to supply blood to brain from aortic arch in thoracic endovascular aortic repair. This study assessed mechanical properties, especially differences in radial force, of different endovascular and thoracic stents. We analyzed the radial force of three stent models (Epic, E-Luminexx and SMART) stents using radial force-tester method in single or overlapping conditions. We also analyzed radial force in three thoracic stents using Mylar film testing method: conformable Gore-TAG, Relay, and Valiant Thoracic Stent Graft. Overlapping SMART stents had greater radial force than overlapping Epic or Luminexx stents (P < 0.01). The radial force of the thoracic stents was greater than that of all three endovascular stents (P < 0.01). Differences in radial force depend on types of stents, site of deployment, and layer characteristics. In clinical settings, an understanding of the mechanical characteristics, including radial force, is important in choosing a stent for each patient. © The Author(s) 2015.

Assessment of In-Stent Restenosis Using 64-MDCT: Analysis of the CORE-64 Multicenter International Trial

PubMed Central

Wykrzykowska, Joanna J.; Arbab-Zadeh, Armin; Godoy, Gustavo; Miller, Julie M.; Lin, Shezhang; Vavere, Andrea; Paul, Narinder; Niinuma, Hiroyuki; Hoe, John; Brinker, Jeffrey; Khosa, Faisal; Sarwar, Sheryar; Lima, Joao; Clouse, Melvin E.

2012-01-01

OBJECTIVE Evaluations of stents by MDCT from studies performed at single centers have yielded variable results with a high proportion of unassessable stents. The purpose of this study was to evaluate the accuracy of 64-MDCT angiography (MDCTA) in identifying in-stent restenosis in a multicenter trial. MATERIALS AND METHODS The Coronary Evaluation Using Multidetector Spiral Computed Tomography Angiography Using 64 Detectors (CORE-64) Multicenter Trial and Registry evaluated the accuracy of 64-MDCTA in assessing 405 patients referred for coronary angiography. A total of 75 stents in 52 patients were assessed: 48 of 75 stents (64%) in 36 of 52 patients (69%) could be evaluated. The prevalence of in-stent restenosis by quantitative coronary angiography (QCA) in this subgroup was 23% (17/75). Eighty percent of the stents were ≤ 3.0 mm in diameter. RESULTS The overall sensitivity, specificity, positive predictive value, and negative predictive value to detect 50% in-stent stenosis visually using MDCT compared with QCA was 33.3%, 91.7%, 57.1%, and 80.5%, respectively, with an overall accuracy of 77.1% for the 48 assessable stents. The ability to evaluate stents on MDCTA varied by stent type: Thick-strut stents such as Bx Velocity were assessable in 50% of the cases; Cypher, 62.5% of the cases; and thinner-strut stents such as Taxus, 75% of the cases. We performed quantitative assessment of in-stent contrast attenuation in Hounsfield units and correlated that value with the quantitative percentage of stenosis by QCA. The correlation coefficient between the average attenuation decrease and ≥ 50% stenosis by QCA was 0.25 (p = 0.073). Quantitative assessment failed to improve the accuracy of MDCT over qualitative assessment. CONCLUSION The results of our study showed that 64-MDCT has poor ability to detect in-stent restenosis in small-diameter stents. Evaluability and negative predictive value were better in large-diameter stents. Thus, 64-MDCT may be appropriate for stent assessment in only selected patients. PMID:20028909

A critical view of the peripheral atherectomy data in the treatment of infrainguinal arterial disease.

PubMed

Quevedo, Henry C; Arain, Salman A; Ali, Gholam; Abi Rafeh, Nidal

2014-01-01

Revascularization of the peripheral arteries remains technically challenging. By decreasing the volume of the atherosclerotic plaque, debulking procedures may confer superior primary patency after revascularization. To assess the impact of atherectomy on primary patency rates at 12 months compared to balloon angioplasty and/or stent placement alone in patients with infrainguinal arterial disease. A database search for "directional," "orbital," "rotational," and "laser atherectomy" in peripheral arterial disease (PAD) was performed. Studies were screened according to the STROBE (Strengthening the Reporting of Observational studies in Epidemiology) critical appraisal tool and summarized by population, methodology, and outcomes (primary patency and major adverse events). Only two randomized studies were found. Most of the data were obtained from single-arm studies and registries. The primary patency with directional atherectomy approaches 60% at 12 months as a stand-alone technique, whereas orbital atherectomy in conjunction with balloon angioplasty and stenting achieved primary patency rates of 90%. Laser atherectomy is universally employed with balloon angioplasty and stenting for in-stent restenosis lesions with a primary patency rate of 64%. Although there are data for the safe use of rotational atherectomy, robust data to support its effectiveness are lacking. The combination of drug-coated balloons and atherectomy for the treatment of heavily calcified lesions in patients with critical limb ischemia is under evaluation. Despite the successful procedural outcomes reported in clinical registries, the available data do not support the use of atherectomy alone in PAD. Larger randomized controlled studies are warranted to define its role in contemporary endovascular practice.

Endoscopic treatment of large pancreatic fluid collections (PFC) using self-expanding metallic stents (SEMS) - a two-center experience.

PubMed

Chaves, Dalton Marques; Mönkemüller, Klaus; Carneiro, Fred; Medrado, Bruno; Dos Santos, Marcos; Wodak, Stephanie; Reimão, Sílvia; Sakai, Paulo; de Moura, Eduardo

2014-12-01

Background/study aim: During the last several years, endoscopic ultrasound (EUS)-guided pancreatic fluid collections' (PFC) drainage has evolved into the preferred drainage technique. Recently, self-expanding metallic stents (SEMS) have been used as an alternative to double pigtail stents, with the advantage of providing a larger diameter fistula, thereby decreasing the risk of early obstruction and also allowing for direct endoscopic exploration of the cavity. The aim of this study was to evaluate the technical and clinical success, safety, and outcome of patients undergoing EUS-guided drainage of complex PFC using SEMS. The study was conducted at two tertiary hospitals from January 2010 to January 2013. All patients with PFC referred for endoscopic drainage were enrolled in a prospective database. The inclusion criteria were: (1) patients with pseudocysts or walled-off necrosis based on the revised Atlanta classification; (2) symptomatic patients with thick PFC; (3) PFC that persisted more than 6 weeks; and (4) large PFC diameter (≥ 9 cm). The exclusion criteria consisted of coagulation disorders, PFC bleeding or infection, and failure-to-inform written consent. A total of 16 patients (9 females, 7 males; mean age 52.6, range 20 - 82) underwent EUS drainage with SEMS. There were 14 cases of pseudocysts and 2 cases of walled-off necrosis. The etiologies of the PFC were mainly gallstones (8 of 16 patients, 50 %) and alcohol (5 of 16 patients, 31 %). Technical success was achieved in 100 % of the cases. All patients had a complete resolution of the PFC. Transmural EUS-guided drainage of complex PFC using SEMS is feasible, appears safe, and is efficacious. However, the exchange of the UC (uncovered)-SEMS for plastic stents is mandatory within 1 week. Future prospective studies, preferably multicenter studies, comparing SEMS versus traditional plastic stents for the drainage of PFC are warranted.

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

Innovative Chimney-Graft Technique for Endovascular Repair of a Pararenal Abdominal Aortic Aneurysm

PubMed Central

Galiñanes, Edgar Luis; Hernandez-Vila, Eduardo A.

2015-01-01

After abdominal aortic aneurysm repair, progressive degeneration of the aneurysm can be challenging to treat. Multiple comorbidities and previous operations place such patients at high risk for repeat surgery. Endovascular repair is a possible alternative; however, challenging anatomy can push the limits of available technology. We describe the case of a 71-year-old man who presented with a 5.3-cm pararenal aneurysm 4 years after undergoing open abdominal aortic aneurysm repair. To avoid reoperation, we excluded the aneurysm by endovascular means, using visceral-artery stenting, a chimney-graft technique. Low-profile balloons on a monorail system enabled the rapid exchange of coronary wires via a buddy-wire technique. This novel approach facilitated stenting and simultaneous angioplasty of multiple visceral vessels and the abdominal aorta. PMID:25873796

Innovative chimney-graft technique for endovascular repair of a pararenal abdominal aortic aneurysm.

PubMed

Galiñanes, Edgar Luis; Hernandez-Vila, Eduardo A; Krajcer, Zvonimir

2015-02-01

After abdominal aortic aneurysm repair, progressive degeneration of the aneurysm can be challenging to treat. Multiple comorbidities and previous operations place such patients at high risk for repeat surgery. Endovascular repair is a possible alternative; however, challenging anatomy can push the limits of available technology. We describe the case of a 71-year-old man who presented with a 5.3-cm pararenal aneurysm 4 years after undergoing open abdominal aortic aneurysm repair. To avoid reoperation, we excluded the aneurysm by endovascular means, using visceral-artery stenting, a chimney-graft technique. Low-profile balloons on a monorail system enabled the rapid exchange of coronary wires via a buddy-wire technique. This novel approach facilitated stenting and simultaneous angioplasty of multiple visceral vessels and the abdominal aorta.

Intraoperative double-J stent insertion in children with scintigraphic impaired renal function and obstructive urinary tract malformation.

PubMed

Erculiani, E; Zampieri, N; Cecchetto, M; Camoglio, F S; Giacomello, L

2008-03-01

Ureteral double-J (DJ) stents are frequently used in modern urologic practice. At present the role of stents in urological and surgical practice and their efficacy in paediatric age are not yet clear. The aim of this study is to evaluate advantages and efficacy of ureteral stents, correlating clinical and radiological data with the permanence of stent in situ. Between July 1999 and July 2004 surgery with ureteral stenting was performed on 24 consecutive patients aged between 2 and 13.5 months with scintigraphic impaired renal function due to an obstructive urinary tract malformation. During the study the performance and the efficacy of indwelling stent have been evaluated through clinical and radiological variables: pre-, intra-, and post stenting blood tests, ultrasonographic and scintigraphic parameters were also evaluated. The stent insertion was useful to improve renal parenchymal thickness and renal growth. No correlation was found between improved blood tests and scintigraphic values. The improvements of clinical and radiological data were strictly correlated with the time of stenting (>3 months). The insertion of DJ stents as long-term internal urinary diversion is useful and safe. Late complications related to the use of stents are not frequent.

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

Endo, Masayuki, E-mail: masay010@yahoo.co.jp; Kaminou, Toshio, E-mail: kaminout@med.tottori-u.ac.jp; Ohuchi, Yasufumi, E-mail: oyasu@med.tottori-u.ac.jp

Purpose: Covered, self-expandable metallic stents (SEMS) have been enthusiastically adopted for the treatment of esophagotracheal fistula, but problems with stent migration have yet to be resolved. To overcome this problem, we have developed a new hanging-type esophageal stent designed to prevent migration, and we conducted an animal study to assess the efficacy of our method. Methods: A total of six female pigs were used in this study. The main characteristic of our stent was the presence of a string tied to the proximal edge of the stent for fixation under the skin of the neck. The first experiment was performedmore » to confirm technical feasibility in three pigs with esophagotracheal fistula. The second experiment was performed to evaluate stent migration and esophagotracheal fistula in three pigs. Results: Creation of the esophagotracheal fistula and stent placement were technically successful in all pigs. In the first experiment, esophagotracheal fistula was sealed by stent placement. In the second experiment, no stent migration was seen 11 or 12 days after stent placement. Gross findings showed no fistulas on the esophageal or tracheal wall. Conclusions: Our new hanging-type esophageal stent seems to offer a feasible method for preventing stent migration.« less

The modified pancreatic stent system for prevention of post-ERCP pancreatitis: a case-control study.

PubMed

Zhang, Cheng; Yang, Yu-Long; Ma, Yue-Feng; Zhang, Hong-Wei; Li, Jing-Yi; Lin, Mei-Ju; Shi, Li-Jun; Qi, Chun-Chun

2017-10-18

Prophylactic pancreatic stents after endoscopic retrograde cholangiopancreatography (ERCP) can help prevent post-ERCP pancreatitis. However most of the pancreatic stents need to be removed by another ERCP. The aim of this observational study was to investigate the feasibility and effectiveness of the modified pancreatic stent system for prevention of post-ERCP pancreatitis. From November 2013 to November 2015, a total of 230 patients who had prophylactic pancreatic stent placed for prevention of post-ERCP pancreatitis at a single institution were identified and stratified. In this case-control design, 150 patients received an ordinary pancreatic stent, and 80 patients received the modified pancreatic stent. The main outcome measures were the difficulty level and complications of pancreatic stent placement and extraction between the two groups. In ordinary group, the average time of pancreatic stent and nasal biliary drainage placement was 3.5 ± 0.6 min. There were 13 cases of stent proximal migration (8.7%), 20 cases of stent spontaneous abscission (13.3%), 5 cases of acute pancreatitis (3.3%) (2 cases for stent abscission) and 7 cases of hyperamylasemia (4.7%) after ERCP. One hundred thirty patients received extra duodenoscope (86.7%) to remove the stent, and 4 cases had acute pancreatitis and 5 patients had hyperamylasemia after removing the proximal migratory stents. In modified group, the average time of pancreatic stent system placement was 4.9 ± 0.7 min, but there was only one case of stent abscission (1.3%), 2 cases of acute pancreatitis (2.5%) and 3 cases of hyperamylasemia (3.8%). The new pancreatic stents were removed directly under x-ray without complication. The modified pancreatic stent system has the same effect of preventing post-ERCP pancreatitis, lower rate of stents proximal migration and spontaneous abscission, and the advantage of easier removed compared with ordinary pancreatic stent.

[Stent-assisted recanalization of femoropopliteal arterial occlusive disease. Influence of stent design on patency rates].

PubMed

Treitl, M; Reiser, M F; Treitl, K M

2016-03-01

Despite enormous technical progress the results of endovascular treatment of the femoropopliteal vasculature are unsatisfactory and its role is still controversially discussed. In the past decade numerous new stent designs have come onto the market but it is unclear whether they have benefits with respect to patency rates. Comparison of published data on patency rates and target lesion revascularization rates after use of different stent designs in the femoropopliteal vasculature. Analysis of 25 published studies and registries from 2006 to 2015 for classical open-cell stents, interwoven stents and partially or fully covered stents. The published data are heterogeneous and comparative studies for different stent designs are completely missing. Over the past decade the patency rates after femoropopliteal stenting could be improved. According to available data stenting of short lesions < 5 cm does not show any benefit compared to isolated balloon angioplasty. Primary stenting is now recommended for intermediate and longer lesions > 6.4 cm. Due to the heterogeneity of published data a clear benefit for a specific stent design is not obvious; however, data for interwoven stents are promising and show a tendency towards improved patency, at least for certain lesions. Randomized controlled comparative trials are needed to confirm this result.

Plastic or metal stents for benign extrahepatic biliary strictures: a systematic review

PubMed Central

2009-01-01

Background Benign biliary strictures may be a consequence of surgical procedures, chronic pancreatitis or iatrogenic injuries to the ampulla. Stents are increasingly being used for this indication, however it is not completely clear which stent type should be preferred. Methods A systematic review on stent placement for benign extrahepatic biliary strictures was performed after searching PubMed and EMBASE databases. Data were pooled and evaluated for technical success, clinical success and complications. Results In total, 47 studies (1116 patients) on outcome of stent placement were identified. No randomized controlled trials (RCTs), one non-randomized comparative studies and 46 case series were found. Technical success was 98,9% for uncovered self-expandable metal stents (uSEMS), 94,8% for single plastic stents and 94,0% for multiple plastic stents. Overall clinical success rate was highest for placement of multiple plastic stents (94,3%) followed by uSEMS (79,5%) and single plastic stents (59.6%). Complications occurred more frequently with uSEMS (39.5%) compared with single plastic stents (36.0%) and multiple plastic stents (20,3%). Conclusion Based on clinical success and risk of complications, placement of multiple plastic stents is currently the best choice. The evolving role of cSEMS placement as a more patient friendly and cost effective treatment for benign biliary strictures needs further elucidation. There is a need for RCTs comparing different stent types for this indication. PMID:20017920

Biofilms and Physical Deposits on Nasolacrimal Silastic Stents Following Dacryocystorhinostomy: Is There a Difference Between Ocular and Nasal Segments?

PubMed

Ali, Mohammad Javed; Baig, Farhana; Lakshman, Mekala; Naik, Milind N

2015-01-01

The aims of this study were to examine the presence of biofilms and physical deposits on ocular and nasal segments of silastic nasolacrimal duct stents inserted after dacryocystorhinostomy and to document any differences. A prospective interventional study was performed on a series of patients undergoing dacryocystorhinostomy with Crawford stent insertion. All the patient samples were retrieved 4 weeks after an endoscopic dacryocystorhinostomy. None of the patients had any evidence of postoperative infection. The ocular and nasal segments were separated during retrieval. After removal, the stent segments were subjected to biofilm and physical deposit analysis using standard protocols of scanning electron microscopy. These stent segments were compared against sterile stents which acted as controls. A total of 11 stents were studied. Nine were consecutive patient samples and 2 were sterile stents. The ocular and nasal segments of all the stents demonstrated evidence of biofilm formation and physical deposits. However, the deposits and biofilms were thicker and extensive in the ocular segment, although more focal in nature. In contrast, the nasal segments showed thinner biofilms and sparser deposits but were more diffuse in nature. The presence of different-sized organisms within the exopolysaccharide matrix and in between the deposits suggests the existence of polymicrobial communities. This is the first study to report the differences between ocular and nasal segments of lacrimal stents. These differences could propel further studies on stent biomechanics and their interactions with ocular and nasal tissues, following a dacryocystorhinostomy.

Bacteriology of urinary tract infection associated with indwelling J ureteral stents.

PubMed

Kehinde, Elijah O; Rotimi, Vincent O; Al-Hunayan, Adel; Abdul-Halim, Hamdy; Boland, Fareeda; Al-Awadi, Khaleel A

2004-11-01

To investigate the microorganisms responsible for urinary tract infection (UTI) and stent colonization in patients with indwelling J ureteral stents and to compare the antimicrobial susceptibility pattern of the isolates from urine and J stents in order to establish the etiologic agents of bacteriuria and colonized stents in such patients and provide baseline data on an antibiotic policy for the urology unit. Midstream urine from 250 patients requiring J stent insertion was investigated microbiologically prior to stent insertion and on the day of stent removal. After stent removal, 3 to 5 cm of the tip located in the bladder was also sent for culture. Patients' bio-data and underlying diseases were documented. Those with no known systemic diseases ("normal patients") were also studied as controls. Of the 250 patients studied, 152 (61%) were normal, while 27 (11%), 53 (21%), and 18 (7%) had diabetes mellitus (DM), chronic renal failure (CRF), and diabetic nephropathy (DN), respectively. The mean duration of stent retention was 27 days. All microbial isolates were tested for their susceptibility to a panel of 10 antibiotics. Twelve patients (5%) before stent insertion and 42 patients (17%; P < 0.001) on the day of stent removal had positive urine cultures. One hundred four stents (42%) were culture positive. Of the 104 patients with positive stent cultures, in 62 patients (60%), urine culture was sterile. The commonest isolates were Escherichia coli, Enterococcus spp., Staphylococcus spp., Pseudomonas, and Candida spp. On the day of stent removal, urine culture was positive in 28% of the normal patients compared with 57% (P = 0.11), 78% (P < 0.001), and 62% (P < 0.001) of patients with CRF, DM, and DN, respectively. Stent isolates were more resistant to antibiotics than the organism isolated before stent insertion. An indwelling J ureteral stent carries a significant risk of bacteriuria and stent colonization. The sensitivity of urine culture to stent colonization is low, and therefore, a negative culture does not rule out a colonized stent. Bacteria cultured from urine after stent insertion and from the stents are more resistant to antibiotics than are those cultured from urine before stent insertion. Norfloxacin or ciprofloxacin is recommended as prophylaxis prior to stent insertion, and an aminoglycoside can be added to treat symptomatic patients with severe infections.

[External biliary fistulas selectively managed by endoscopic retrograde cholangiography with sphincterotomy and/or stent placement].

PubMed

Săftoiu, A; Gheonea, D I; Surlin, V; Ciurea, M E; Georgescu, A; Andrei, E; Blendea, A; Georgescu, C C; Georgescu, I; Ciurea, T

2006-01-01

External bile duct fistulas are inherent postoperative complications that usually appear after biliary tract surgery, traumatic bile duct injuries and liver surgery for hepatic hydatid disease or liver transplant. The management is highly individualized, while the success and long-term results of endoscopic and surgical techniques are conflicting. The study included 32 cases with external bile duct fistulas managed by endoscopic retrograde cholangiography (ERC) with sphincterotomy and/or stent placement, including "rendez-vous" procedures in 2 cases. The causes of the external fistula were represented by cholecystectomy with/without retained common bile duct stones or strictures (22 cases), cholecystectomy and drainage of a subphrenic abscess caused by severe acute pancreatitis (1 case) and surgical interventions for hepatic hydatid disease (9 cases). Due to the prospective protocol of the study we were able to apply an individualized endoscopic treatment: sphincterotomy with proper relief of the bile duct obstruction (stone extraction) or sphincterotomy with large-size (10 Fr) stent placement for large-sized bile duct defects. The results consisted in closure of the fistula in 3.5 +/- 1.7 days for the subgroup of patients with sphincterotomy alone. Among the patients with stent insertion, fistulas healed slower in 14 +/- 3.5 days. There were no complications after endoscopic treatment; however the stent could not be passed in one patient that required subsequent surgery. In conclusion, endoscopic intervention is the treatment of choice for small external biliary fistulas complicating biliary tract surgery or liver surgery for hepatic hydatid disease. When the fistula is large, the placement of a 10 Fr endoprosthesis becomes necessary, while failure of endoscopic treatment leads to surgery with hepatico-jejunal anastomosis.

Outcomes with various drug eluting or bare metal stents in patients with diabetes mellitus: mixed treatment comparison analysis of 22 844 patient years of follow-up from randomised trials

PubMed Central

Kumar, Sunil; Fusaro, Mario; Amoroso, Nicholas; Kirtane, Ajay J; Byrne, Robert A; Williams, David O; Slater, James; Cutlip, Donald E; Feit, Frederick

2012-01-01

Objectives To evaluate the efficacy and safety of currently used drug eluting stents compared with each other and compared with bare metal stents in patients with diabetes. Design Mixed treatment comparison meta-analysis. Data sources and study selection PubMed, Embase, and CENTRAL were searched for randomised clinical trials, until April 2012, of four durable polymer drug eluting stents (sirolimus eluting stents, paclitaxel eluting stents, everolimus eluting stents, and zotarolimus eluting stents) compared with each other or with bare metal stents for the treatment of de novo coronary lesions and enrolling at least 50 patients with diabetes. Primary outcomes Efficacy (target vessel revascularisation) and safety (death, myocardial infarction, stent thrombosis). Results From 42 trials with 22 844 patient years of follow-up, when compared with bare metal stents (reference rate ratio 1) all of the currently used drug eluting stents were associated with a significant reduction in target vessel revascularisation (37% to 69%), though the efficacy varied with the type of stent (everolimus eluting stents∼sirolimus eluting stents>paclitaxel eluting stents∼zotarolimus eluting stent>bare metal stents). There was about an 87% probability that everolimus eluting stents were the most efficacious compared with all others, though there were limited usable data for the zotarolimus eluting Resolute stent in patients with diabetes. Moreover, there was no increased risk of any safety outcome (including very late stent thrombosis) with any drug eluting stents compared with bare metal stents. There was about a 62% probability that the everolimus eluting stent was the safest stent for the outcome of “any” stent thrombosis. Conclusions Among patients with diabetes treated with coronary stents all currently available drug eluting stents were efficacious without compromising safety compared with bare metal stents. There were relative differences among the drug eluting stents, such that the everolimus eluting stent was the most efficacious and safe. PMID:22885395

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.

Timing of silicone stent removal in patients with post-tuberculosis bronchial stenosis

PubMed Central

Eom, Jung Seop; Kim, Hojoong; Park, Hye Yun; Jeon, Kyeongman; Um, Sang-Won; Koh, Won-Jung; Suh, Gee Young; Chung, Man Pyo; Kwon, O. Jung

2013-01-01

CONTEXT: In patients with post-tuberculosis bronchial stenosis (PTBS), the severity of bronchial stenosis affects the restenosis rate after the silicone stent is removed. In PTBS patients with incomplete bronchial obstruction, who had a favorable prognosis, the timing of stent removal to ensure airway patency is not clear. AIMS: We evaluated the time for silicone stent removal in patients with incomplete PTBS. SETTINGS AND DESIGN: A retrospective study examined PTBS patients who underwent stenting and removal of a silicone stent. METHODS: Incomplete bronchial stenosis was defined as PTBS other than total bronchial obstruction, which had a luminal opening at the stenotic segment on bronchoscopic intervention. The duration of stenting was defined as the interval from stent insertion to removal. The study included 44 PTBS patients and the patients were grouped at intervals of 6 months according to the duration of stenting. RESULTS: Patients stented for more than 12 months had a significantly lower restenosis rate than those stented for less than 12 months (4% vs. 35%, P = 0.009). Multiple logistic regression revealed an association between stenting for more than 12 months and a low restenosis rate (odds ratio 12.095; 95% confidence interval 1.097-133.377). Moreover, no restenosis was observed in PTBS patients when the stent was placed more than 14 months previously. CONCLUSIONS: In patients with incomplete PTBS, stent placement for longer than 12 months reduced restenosis after stent removal. PMID:24250736

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.

Satisfactory short-term outcomes of the STABILISE technique for type B aortic dissection.

PubMed

Melissano, Germano; Bertoglio, Luca; Rinaldi, Enrico; Mascia, Daniele; Kahlberg, Andrea; Loschi, Diletta; De Luca, Monica; Monaco, Fabrizio; Chiesa, Roberto

2018-03-29

The aim of this study was to evaluate the perioperative and short-term results in a cohort of patients treated during the last year at our institution with the stent-assisted balloon-induced intimal disruption and relamination in aortic dissection repair (STABILISE) technique for acute complicated aortic dissection. Between June 2016 and June 2017, 10 patients (all male; mean age, 62.6 ± 7.4 years) received treatment for acute complicated aortic dissection with the STABILISE technique. After a standard provisional extension to induce complete attachment procedure using the commercially available endovascular dissection system (Cook Medical, Bloomington, Ind), the distal stent graft area and the bare stent area were ballooned to completely exclude the thoracic false lumen (FL) and to obtain a single-channeled abdominal aorta. Computed tomography was routinely performed within the first postoperative week before discharge and then at 3 months, at 6 months, and yearly thereafter. The technical and clinical success rates were analyzed. The 30-day technical and clinical success rates were 100%, with complete thrombosis of the thoracic FL and no type I endoleak. Malperfusion was resolved in all cases. No aortic ruptures were recorded, and no open conversion was required. One case of delayed spinal cord ischemia fully resolved within the discharge period. Predischarge computed tomography showed complete thrombosis of the thoracic FL in all cases. In two cases, some degree of patency of the abdominal FL was observed. At short-term follow-up, the overall aortic diameters remained stable with no further dilation. The STABILISE technique was safe and feasible in this cohort of patients, with complete thrombosis of the thoracic FL and creation of a single-channeled aorta in most cases. Further studies are needed to ascertain the long-term behavior of the treated aorta. Copyright © 2018 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

The Evolution of Transjugular Intrahepatic Portosystemic Shunt: Tips

PubMed Central

Fanelli, Fabrizio

2014-01-01

Since Richter's description in the literature in 1989 of the first procedure on human patients, transjugular intrahepatic portosystemic shunt (TIPS) has been worldwide considered as a noninvasive technique to manage portal hypertension complications. TIPS succeeds in lowering the hepatic sinusoidal pressure and in increasing the circulatory flow, thus reducing sodium retention, ascites recurrence, and variceal bleeding. Required several revisions of the shunt TIPS can be performed in case of different conditions such as hepatorenal syndrome, hepatichydrothorax, portal vein thrombosis, and Budd-Chiari syndrome. Most of the previous studies on TIPS procedure were based on the use of bare stents and most patients chose TIPS 2-3 years after traditional treatment, thus making TIPS appear to be not superior to endoscopy in survival rates. Bare stents were associated with higher incidence of shunt failure and consequently patients required several revisions during the follow-up. With the introduction of a dedicated e-PTFE covered stent-graft, these problems were completely solved, No more reinterventions are required with a tremendous improvement of patient's quality of life. One of the main drawbacks of the use of e-PTFE covered stent-graft is higher incidence of hepatic encephalopathy. In those cases refractory to the conventional medical therapy, a shunt reduction must be performed. PMID:27335841

A novel animal model for hyperdynamic airway collapse.

PubMed

Tsukada, Hisashi; O'Donnell, Carl R; Garland, Robert; Herth, Felix; Decamp, Malcolm; Ernst, Armin

2010-12-01

Tracheobronchomalacia (TBM) is increasingly recognized as a condition associated with significant pulmonary morbidity. However, treatment is invasive and complex, and because there is no appropriate animal model, novel diagnostic and treatment strategies are difficult to evaluate. We endeavored to develop a reliable airway model to simulate hyperdynamic airway collapse in humans. Seven 20-kg male sheep were enrolled in this study. Tracheomalacia was created by submucosal resection of > 50% of the circumference of 10 consecutive cervical tracheal cartilage rings through a midline cervical incision. A silicone stent was placed in the trachea to prevent airway collapse during recovery. Tracheal collapsibility was assessed at protocol-specific time points by bronchoscopy and multidetector CT imaging while temporarily removing the stent. Esophageal pressure and flow data were collected to assess flow limitation during spontaneous breathing. All animals tolerated the surgical procedure well and were stented without complications. One sheep died at 2 weeks because of respiratory failure related to stent migration. In all sheep, near-total forced inspiratory airway collapse was observed up to 3 months postprocedure. Esophageal manometry demonstrated flow limitation associated with large negative pleural pressure swings during rapid spontaneous inhalation. Hyperdynamic airway collapse can reliably be induced with this technique. It may serve as a model for evaluation of novel diagnostic and therapeutic strategies for TBM.

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

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

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.

Outcomes of second self-expandable metallic stent insertion for malignant gastric outlet obstruction.

PubMed

Kim, Chan Gyoo; Choi, Il Ju; Lee, Jong Yeul; Cho, Soo-Jeong; Kim, Soo Jin; Kim, Mi-Jung; Park, Sook Ryun; Park, Young Lee

2014-01-01

Self-expandable metallic stents are used widely to relieve malignant gastric outlet obstruction (GOO). However, restenosis or migration of first stents is a frequent complication. The purpose of this retrospective cohort study was to evaluate the effectiveness of second stents as an approach to manage failure of first stents in patients with malignant GOO. A total of 222 patients with gastric cancer received first stents due to inoperable GOO at National Cancer Center in Korea between January 2008 and June 2011. Monthly follow-up interviews were performed, and second stents (stent-in-stent or stent-after-migration) were inserted in 59 patients by June 2012. Technical and clinical successes and long-term complications were evaluated. The technical and immediate clinical success rates were 98.3 % (58/59) and 91.5 % (54/59), respectively. Patients who received a second stent due to late complications involving the first stent (migration, restenosis, and fracture) showed a higher clinical success rate (95.8 % [46/48]) than patients who received a second stent due to immediate clinical failure of the first stent (72.7 % [8/11], p = 0.04). The immediate clinical success rate of stent-after-migration (100 % [11/11]) was not different from that of stent-in-stent (89.6 % [43/48], p = 1.0). The stent dysfunction rate of stent-after-migration (27.3 % [3/11]) also was similar to that of stent-in-stent (29.2 % [14/48], p = 1.0). The median patencies of stent-in-stent and stent-after-migration were 27.4 and 58.4 weeks, respectively (p = 0.177). There were no significant prognostic factors for patency of second stents. Insertion of a second stent is effective for treating the first-stent failure in gastric cancer patients with GOO, especially if the immediate outcome of the first stent was successful.

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.

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.

Are there fewer complications with third generation endografts in endovascular aneurysm repair?

PubMed

Jayia, P; Constantinou, J; Morgan-Rowe, L; Schroeder, T V; Lonn, L; Ivancev, K

2013-02-01

Endovascular aneurysm repair (EVAR) is widely accepted as a safe technique for treatment of aortic diseases since the concept was first pioneered by Volodos in 1986 and Parodi in 1991. Numerous registries have shown that this minimally invasive technique is associated with lower mortality when compared to open surgery in short and mid-term follow-up. The first pioneer devices had a high failure rate due to stent migration. This led to the creation of the first generation stent-grafts, which were associated with complications such as thrombosis of the limbs, graft migration and major endoleaks. The majority of these endostents are now withdrawn from the commercial market. However, these patients need lifelong surveillance because of a considerable risk of late complications. The materials used in the stent-graft vary with each manufacturer. Low porous fabric, suprarenal fixation and low profile devices led to the development of the second generation stent-grafts. The improvements with regards to the delivery systems, enabled reposition of the top-stent following deployment in some devices. The number of devices commercially available increased with the second generation. The third generation of stent-grafts, allowed treatment of complex aortic disease. Custom made solutions incorporate small openings, fenestrations for vessels involved in the aneurysmal disease and is already built in today's technology and available as CE marked devices. The device can be built with combinations of various branches and fenestrations in order to best accommodate the aortic anatomy of the patient. However, many issues remain with the development of this technology. There is a need for durable systems with less complicated deployment mechanics in order to be applied and more widespread. In conclusion, the third generation endografts in challenging anatomy has yielded encouraging results. With regards to short and midterm outcome and need for secondary interventions, evaluations shows comparable results with all devices performing well.

[The Predictive Factors of Stent Failure in the Treatment of Malignant Extrinsc Ureteral Obstruction Using Internal Ureteral Stents].

PubMed

Matsuura, Hiroshi; Arase, Shigeki; Hori, Yasuhide; Tochigi, Hiromi

2017-12-01

In this study, we retrospectively reviewed the experiences at our single institute in the treatment of malignant extrinsic ureteral obstruction (MUO) using ureteral stents to investigate the clinical outcomes and the predictive factors of stent failure. In 52 ureters of 38 patients who had radiologically significant hydronephrosis due to MUO, internal ureteral stents (The BARD(R) INLAY(TM) ureteral stent set) were inserted. The median follow-up interval after the initial stent insertion was 124.5 days (4-1,120). Stent failure occurred in 8 ureters (15.4%) of the 7 patients. The median interval from the first stent insertion to stent failure was 88 days (1-468). A Cox regression multivariate analysis showed that the significant predictors of stent failure were bladder invasion. Based on the possibility of stent failure, the adaptation of the internal ureteral stent placement should be considered especially in a patient with MUO combined with bladder invasion.

Endoscopic stenting for benign upper gastrointestinal strictures and leaks.

PubMed

Sharaiha, Reem Z; Kim, Katherine J; Singh, Vikesh K; Lennon, Anne Marie; Amateau, Stuart K; Shin, Eun Ji; Canto, Marcia Irene; Kalloo, Anthony N; Khashab, Mouen A

2014-01-01

Self-expandable metal stents (SEMS) and self-expandable plastic stents (SEPS) maybe used for the treatment of benign upper gastrointestinal (GI) leaks and strictures. This study reviewed our experience with stent insertions in patients with benign upper GI conditions. Patients who underwent stent placement for benign upper GI strictures and leaks between March 2007 and April 2011 at a tertiary referral academic center were studied using an endoscopic database and electronic patient records. The technical success, complications, and clinical improvement after stent removal were compared according to type of stent. The outcomes measured were clinical response, adverse events, and predictors of stent migration. Thirty-eight patients (50 % male, mean age = 54 years, range = 12-82) underwent 121 endoscopic procedures. Twenty patients had stents placed for strictures, and 18 had stents placed for leaks. Stent placement was technically successful in all patients. The average duration of stent placement was 54 days (range = 18-118). Clinical improvement immediately after stent placement was seen in 29 of the 38 patients (76.3 %). Immediate post-procedure adverse events occurred in 8 patients. Late adverse events were seen in 18 patients. Evidence of stent migration occurred in 16 patients and was seen in 42 of the 118 successfully placed stents (35.5 %). Migration was more frequent with fully covered SEMS (p = 0.002). After stent removal, 27 patients were evaluable for long-term success (median follow-up time of 283 days, IQR 38-762). Resolution of strictures or leaks was seen in 11 patients (40.7 %). Predictors for long-term success included increasing age and if the stent did not cross the GE junction. Placement of SEPS and SEMS for benign refractory strictures and fistulas has modest long-term clinical efficacy and is limited by a significant migration rate. Stent migration is common and frequent with fully covered SEMS compared to other types of stents, regardless of indication or location.

Tracheal ceramic rings for tracheomalacia: a review after 17 years.

PubMed

Göbel, Gyula; Karaiskaki, Niki; Gerlinger, Imre; Mann, Wolf J

2007-10-01

Despite different support techniques, the surgical management of tracheomalacia is still a challenging problem. Satisfactory results after internal stenting are above 80%, whereas, when performing external stenting using biocompatible ceramic rings, results are reported at over 90%. The purpose of this study was to examine the efficiency of surgical treatment in patients with segmentary tracheomalacia using external ceramic ring grafts. In this retrospective study, we collected data from 12 patients who underwent surgery during the last 17 years for symptomatic segmentary tracheomalacia by use of biocompatible aluminum-oxide ceramic rings. All except one patient had undergone previous tracheostomy, six had a history of long-term intubation, two had previous trauma, and two patients had previous cancer treatment including radiotherapy. One of the patients still had an existing tracheostoma, which was closed when a ceramic ring was implanted. Tracheal wall collapse with pseudoglottis formation or flattened anterior-posterior tracheal diameter was documented with fiberoscopy at rest, and both pre- and postoperative airway resistance measurements were performed in all 12 patients using a spirometer. After malacic segments were found to be expandable using rigid tracheoscopy while the patient was under general anesthesia, preparation of the trachea was performed using a midline vertical incision in the neck. Subsequently, the malacic trachea was expanded by placing and suturing proper-sized ceramic ring(s) around it. In all patients, surgical expansion of the malacic segment using ceramic rings was successfully carried out without major complications while inspiratory stridor was resolved. Airway resistance decreased significantly from an average of 0.62 to 0.385 kPascal. Although the results of applying internal tracheal stents are encouraging, complications such as stent migration, granulation tissue and fistula formation, and mucociliary transport arrest are possible. Biocompatible ceramic rings do not cause foreign body reactions, remain stabile, and, with a proper suturing technique, provide a suitable long-term solution.

Internal versus external ureteric stents for uretero-ileal anastomosis after laparoscopic radical cystectomy with orthotopic neobladder: A prospective comparative study.

PubMed

Abdel Hakim, Mahmoud A; Abdalla, Ahmed A; Saad, Ismail R; ElSheemy, Mohammed S; El Feel, Ahmed S; Salem, Hosni K; Abdel Hakim, Amr M

2016-06-01

To prospectively compare the use of external ureteric stents with internal JJ stenting of the uretero-ileal anastomosis in patients undergoing laparoscopic radical cystectomy (LRC) with a Y-shaped ileal orthotopic neobladder (ON). The study included 69 patients undergoing LRC with ON. Patients were grouped according to the type of uretero-ileal stents used. An external ureteric stent was used in Group A (33 patients) and a JJ stent was used in Group B (36). We prospectively compared the duration of hospital stay, the incidence of short- and intermediate-term complications in the two study groups. The mean (SD) follow-up periods were 29.18 (3.94) and 28.19 (3.37) months for patients in Groups A and B, respectively. Perioperative patient characteristics were comparable in the two study groups. The use of JJ stenting was associated with a shorter hospital stay compared with external stenting, at a mean (SD) of 14.63 (3.74) and 6.8 (3.03) days in Groups A and B, respectively (P < 0.001). The incidence of urinary leakage was comparable in the two study groups, at 6.1% in Group A vs 8.3% in Group B (P = 1.0). Strictures of the uretero-ileal anastomosis occurred in two patients (6%) in Group A and confirmed by intravenous urography. All strictures were treated with antegrade JJ fixation. JJ stents could be used as an effective alternative to external ureteric stents to support the uretero-ileal anastomosis. JJ stenting is associated with a shorter hospital stay and similar complication rates compared with external stenting in patients undergoing LRC with ON.

Photon Counting Computed Tomography With Dedicated Sharp Convolution Kernels: Tapping the Potential of a New Technology for Stent Imaging.

PubMed

von Spiczak, Jochen; Mannil, Manoj; Peters, Benjamin; Hickethier, Tilman; Baer, Matthias; Henning, André; Schmidt, Bernhard; Flohr, Thomas; Manka, Robert; Maintz, David; Alkadhi, Hatem

2018-05-23

The aims of this study were to assess the value of a dedicated sharp convolution kernel for photon counting detector (PCD) computed tomography (CT) for coronary stent imaging and to evaluate to which extent iterative reconstructions can compensate for potential increases in image noise. For this in vitro study, a phantom simulating coronary artery stenting was prepared. Eighteen different coronary stents were expanded in plastic tubes of 3 mm diameter. Tubes were filled with diluted contrast agent, sealed, and immersed in oil calibrated to an attenuation of -100 HU simulating epicardial fat. The phantom was scanned in a modified second generation 128-slice dual-source CT scanner (SOMATOM Definition Flash, Siemens Healthcare, Erlangen, Germany) equipped with both a conventional energy integrating detector and PCD. Image data were acquired using the PCD part of the scanner with 48 × 0.25 mm slices, a tube voltage of 100 kVp, and tube current-time product of 100 mAs. Images were reconstructed using a conventional convolution kernel for stent imaging with filtered back-projection (B46) and with sinogram-affirmed iterative reconstruction (SAFIRE) at level 3 (I463). For comparison, a dedicated sharp convolution kernel with filtered back-projection (D70) and SAFIRE level 3 (Q703) and level 5 (Q705) was used. The D70 and Q70 kernels were specifically designed for coronary stent imaging with PCD CT by optimizing the image modulation transfer function and the separation of contrast edges. Two independent, blinded readers evaluated subjective image quality (Likert scale 0-3, where 3 = excellent), in-stent diameter difference, in-stent attenuation difference, mathematically defined image sharpness, and noise of each reconstruction. Interreader reliability was calculated using Goodman and Kruskal's γ and intraclass correlation coefficients (ICCs). Differences in image quality were evaluated using a Wilcoxon signed-rank test. Differences in in-stent diameter difference, in-stent attenuation difference, image sharpness, and image noise were tested using a paired-sample t test corrected for multiple comparisons. Interreader and intrareader reliability were excellent (γ = 0.953, ICCs = 0.891-0.999, and γ = 0.996, ICCs = 0.918-0.999, respectively). Reconstructions using the dedicated sharp convolution kernel yielded significantly better results regarding image quality (B46: 0.4 ± 0.5 vs D70: 2.9 ± 0.3; P < 0.001), in-stent diameter difference (1.5 ± 0.3 vs 1.0 ± 0.3 mm; P < 0.001), and image sharpness (728 ± 246 vs 2069 ± 411 CT numbers/voxel; P < 0.001). Regarding in-stent attenuation difference, no significant difference was observed between the 2 kernels (151 ± 76 vs 158 ± 92 CT numbers; P = 0.627). Noise was significantly higher in all sharp convolution kernel images but was reduced by 41% and 59% by applying SAFIRE levels 3 and 5, respectively (B46: 16 ± 1, D70: 111 ± 3, Q703: 65 ± 2, Q705: 46 ± 2 CT numbers; P < 0.001 for all comparisons). A dedicated sharp convolution kernel for PCD CT imaging of coronary stents yields superior qualitative and quantitative image characteristics compared with conventional reconstruction kernels. Resulting higher noise levels in sharp kernel PCD imaging can be partially compensated with iterative image reconstruction techniques.

Carotid Artery Stenting Using a Novel Self-Expanding Braided Nickel-Titanium Stent: Feasibility and Safety Porcine Trial

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

Ahlhelm, Frank, E-mail: frah1@gmx.de; Kaufmann, Ralf, E-mail: ralf.kaufmann@vascomed.d; Ahlhelm, Dirk, E-mail: ahlhelmd@gmx.de

We studied the deliverability and safety of a braided, self-expanding, closed-cell nickel-titanium (NiTi) stent (E-volution, Jotec GmbH, Hechingen, Germany) especially designed for the endovascular treatment of carotid artery bifurcation stenosis with special regard to in-stent stenosis and thrombosis compared with a laser-cut reference nitinol stent in a porcine model of percutaneous vascular interventions. We aimed to assess histopathologic response in minipig carotid and subclavian arteries. Eight minipigs received a total of 42 stents: 14 reference stents and 28 E-volution stents. Eleven of the E-volution stents were additionally coated with heparin. Control angiography was obtained immediately before and after vascular interventionmore » as well as 4 weeks after the procedure. Primary endpoints were 28 days of angiographic analyses as well as histomorphometric analysis, including injury score, inflammation score, luminal diameter, vessel diameter, maximal neointimal thickness, and area of in-stent stenosis. Secondary end points were procedural success, 28-day mortality, and stent thrombosis. All stents could be delivered successfully without procedural complications, morbidity, or mortality during our observation time. As confirmed by histology, no in-stent thrombosis was observed. Compared with common carotid arteries, subclavian arteries are significantly more vulnerable to developing in-stent stenosis caused by neointima proliferation (p < 0.05). Compared with the use of 1 single stent/artery, serial application of two stents leads to a more excessive but not significantly different neointimal proliferation (p > 0.05). The E-volution stent, especially when heparin coated, is in line with the comparison to the laser-cut reference stent displaying similar results of angiographic, histologic, and histomorphometric analyses (p > 0.05). Compared with the reference laser-cut stent, the self-expanding nitinol stent (E-volution) with its advanced braiding technology is feasible and safe. In our opinion, the high radial resistive force and the advanced braided design with tight stent-strut interstices may be beneficial in terms of plaque stabilization. Further studies are necessary and warranted.« less

Newly designed plastic stent for endoscopic placement above the sphincter of Oddi in patients with malignant hilar biliary obstruction.

PubMed

Ishiwatari, Hirotoshi; Hayashi, Tsuyoshi; Ono, Michihiro; Sato, Tsutomu; Kato, Junji

2013-05-01

Plastic stent (PS) occlusion occurs as a result of bacterial adherence to the stent's inner wall. To retain the bacteriological barrier, placing a PS above the sphincter of Oddi ('inside stent') has been investigated. We designed a new PS (inside stent with thread [IT] stent) with attachable nylon thread for use as an inside stent and for easy retrieval. The present study evaluated the IT stent's technical feasibility and efficacy for malignant hilar biliary obstruction. A total of 26 consecutive patients with unresectable malignant hilar biliary obstruction underwent placement of IT stents from August 2007 to February 2011. IT stents were placed across the strictures without sphincterotomy to achieve bilateral drainage. The overall technical success rate of the IT stent was 100% for one session. Multiple IT stents were inserted in 25 cases(two stents in 15 patients, three stents in 10 patients). No stent-related early complications occurred. The functional success rate was 92% (24/26). The rate of reintervention because of stent malfunction was 50% (13/26). In all 16 patients who underwent stent removal, IT stents were easily retrieved using the nylon thread. According to Kaplan-Meier analysis, the median stent patency period was 136 days. IT stents for endoscopic placement above the sphincter of Oddi can be used safely and effectively for malignant hilar biliary obstruction. © 2013 The Authors. Digestive Endoscopy © 2013 Japan Gastroenterological Endoscopy Society.

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

Computational fluid dynamics analysis of balloon-expandable coronary stents: influence of stent and vessel deformation.

PubMed

Martin, David M; Murphy, Eoin A; Boyle, Fergal J

2014-08-01

In many computational fluid dynamics (CFD) studies of stented vessel haemodynamics, the geometry of the stented vessel is described using non-deformed (NDF) geometrical models. These NDF models neglect complex physical features, such as stent and vessel deformation, which may have a major impact on the haemodynamic environment in stented coronary arteries. In this study, CFD analyses were carried out to simulate pulsatile flow conditions in both NDF and realistically-deformed (RDF) models of three stented coronary arteries. While the NDF models were completely idealised, the RDF models were obtained from nonlinear structural analyses and accounted for both stent and vessel deformation. Following the completion of the CFD analyses, major differences were observed in the time-averaged wall shear stress (TAWSS), time-averaged wall shear stress gradient (TAWSSG) and oscillatory shear index (OSI) distributions predicted on the luminal surface of the artery for the NDF and RDF models. Specifically, the inclusion of stent and vessel deformation in the CFD analyses resulted in a 32%, 30% and 31% increase in the area-weighted mean TAWSS, a 3%, 7% and 16% increase in the area-weighted mean TAWSSG and a 21%, 13% and 21% decrease in the area-weighted mean OSI for Stents A, B and C, respectively. These results suggest that stent and vessel deformation are likely to have a major impact on the haemodynamic environment in stented coronary arteries. In light of this observation, it is recommended that these features are considered in future CFD studies of stented vessel haemodynamics. Copyright © 2014 IPEM. Published by Elsevier Ltd. All rights reserved.

A computational study of crimping and expansion of bioresorbable polymeric stents

NASA Astrophysics Data System (ADS)

Qiu, T. Y.; Song, M.; Zhao, L. G.

2018-05-01

This paper studied the mechanical performance of four bioresorbable PLLA stents, i.e., Absorb, Elixir, Igaki-Tamai and RevaMedical, during crimping and expansion using the finite element method. Abaqus CAE was used to create the geometrical models for the four stents. A tri-folded balloon was created using NX software. For the stents, elastic-plastic behaviour was used, with hardening implemented by considering the increase of yield stress with the plastic strain. The tri-folded balloon was treated as linear elastic. To simulate the crimping of stents, a set of 12 rigid plates were generated around the stents with a radially enforced displacement. During crimping, the stents were compressed from a diameter of 3 mm to 1.2 mm, with the maximum stress developed at both inner and outer sides of the U-bends. During expansion, the stent inner diameter increased to 3 mm at the peak pressure and then recoiled to different final diameters after balloon deflation due to different stent designs. The maximum stress was found again at the U-bends of stents. Diameter change, recoiling effect and radial strength/stiffness were also compared for the four stents to assess the effect of design variation on stent performance. The effect of loading rate on stent deformation was also simulated by considering the time-dependent plastic behaviour of polymeric material.

A computational study of crimping and expansion of bioresorbable polymeric stents

NASA Astrophysics Data System (ADS)

Qiu, T. Y.; Song, M.; Zhao, L. G.

2017-10-01

This paper studied the mechanical performance of four bioresorbable PLLA stents, i.e., Absorb, Elixir, Igaki-Tamai and RevaMedical, during crimping and expansion using the finite element method. Abaqus CAE was used to create the geometrical models for the four stents. A tri-folded balloon was created using NX software. For the stents, elastic-plastic behaviour was used, with hardening implemented by considering the increase of yield stress with the plastic strain. The tri-folded balloon was treated as linear elastic. To simulate the crimping of stents, a set of 12 rigid plates were generated around the stents with a radially enforced displacement. During crimping, the stents were compressed from a diameter of 3 mm to 1.2 mm, with the maximum stress developed at both inner and outer sides of the U-bends. During expansion, the stent inner diameter increased to 3 mm at the peak pressure and then recoiled to different final diameters after balloon deflation due to different stent designs. The maximum stress was found again at the U-bends of stents. Diameter change, recoiling effect and radial strength/stiffness were also compared for the four stents to assess the effect of design variation on stent performance. The effect of loading rate on stent deformation was also simulated by considering the time-dependent plastic behaviour of polymeric material.

Covered versus uncovered self-expandable metal stents for malignant biliary strictures: A meta-analysis and systematic review.

PubMed

Moole, Harsha; Bechtold, Matthew L; Cashman, Micheal; Volmar, Fritz H; Dhillon, Sonu; Forcione, David; Taneja, Deepak; Puli, Srinivas R

2016-09-01

Self-expandable metal stents (SEMS) are used for palliating inoperable malignant biliary strictures. It is unclear if covered metal stents are superior to uncovered metal stents in these patients. We compared clinical outcomes in patients with covered and uncovered stents. Studies using covered and uncovered metallic stents for palliation in patients with malignant biliary stricture were reviewed. Articles were searched in MEDLINE, PubMed, and Ovid journals. Fixed and random effects models were used to calculate the pooled proportions. Initial search identified 1436 reference articles, of which 132 were selected and reviewed. Thirteen studies (n = 2239) for covered and uncovered metallic stents which met the inclusion criteria were included in this analysis. Odds ratio for stent occlusion rates in covered vs. uncovered stents was 0.79 (95 % CI = 0.65 to 0.96). Survival benefit in patients with covered vs. uncovered stents showed the odds ratio to be 1.29 (95 % CI = 0.95 to 1.74). Pooled odds ratio for migration of covered vs. uncovered stents was 9.9 (95 % CI = 4.5 to 22.3). Covered stents seemed to have significantly lesser occlusion rates, increased odds of migration, and increased odds of pancreatitis compared to uncovered stents. There was no statistically significant difference in the survival benefit, overall adverse event rate, and patency period of covered vs. uncovered metal stents in patients with malignant biliary strictures.

Embolization of the Internal Iliac Artery: Cost-Effectiveness of Two Different Techniques

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

Pellerin, Olivier, E-mail: olivier.pellerin@egp.aphp.f; Caruba, Thibaud; Kandounakis, Yanis

2008-11-15

The purpose of this study was to compare the cost-effectiveness of coils versus the Amplatzer Vascular Plug (AVP) for occlusion of the internal iliac artery (IAA). Between 2002 and January 2006, 13 patients (mean age 73 {+-} 13 years) were referred for stent-grafting of abdominal aortic aneurysm (n = 6); type I distal endoleak (n = 3), isolated iliac aneurysm (n = 3), or rupture of a common iliac aneurysm (n = 1). In all patients, extension of the stent-graft was needed because the distal neck was absent. Two different techniques were used to occlude the IIA: AVP in sevenmore » patients (group A) and coil embolization in six patients (group C). Immediate results and direct material costs were assessed retrospectively. Immediate success was achieved in all patients, and simultaneous stent-grafting was successfully performed in two of six patients in group C versus five of seven patients in group A. In all group A patients, a single AVP was sufficient to achieve occlusion of the IIA, accounting for a mean cost of 485 Euro , whereas in group C patients, an average of 7 {+-} 3 coils were used, accounting for a mean cost of 1,745 Euro . Mean average cost savings using the AVP was 1,239 Euro . When IIA occlusion is needed, the AVP allows a single-step procedure at significant cost savings.« less

Tracheal reaction to three different intraluminal stents in an animal model of tracheomalacia.

PubMed

Weinberg, Mark; Sandbank, Judith; Flumenblit, Yoseph; Klin, Baruch; Vinograd, Itzhak

2005-06-01

Three different internal airway stents were studied in an animal model of tracheomalacia: the Palmaz stent (Johnson & Johnson, Warren, New Jersey) and the NIR stent (Medinol Ltd., Tel Aviv, Israel)--both made of stainless steel in the form of tubular mesh--and the Nitinol stent, made of nickel-titanium formed into a spiral shape. All three stents could be adequately stabilized in the malacic tracheal segment. The Nitinol stent (Medinol Ltd., Tel Aviv, Israel) proved to be less reactive to the tracheal mucosa, demonstrated higher biocompatibility with significantly less granulation tissue formation, and showed superior radial resistance. Extraction of the Nitinol stent also proved to be much smoother. This stent may be the stent of choice in the treatment of tracheo- and bronchomalacia.

Endoscopic dacryocystorhinostomy without silicone stent.

PubMed

Yeon, Je Yeob; Shim, Woo Sub

2012-06-01

In nasolacrimal duct (NLD) obstruction patients that undergo endoscopic dacryocystorhinostomy (DCR), creation of a patent rhinostomy with adequate epithelialization can be accomplished without a stent. However, in common canalicular obstruction patients, a silicone stent seems to have a beneficial role and to bear more favorable results. The aim of this study was to evaluate the surgical outcome of endoscopic DCR without the use of a silicone stent. In all, 36 patients (41 eyes) who underwent endoscopic DCR were enrolled in this study. The patients were classified into a DCR with silicone stent group and a DCR without silicone stent group. Then each of the groups was subdivided into common canalicular obstruction group and NLD obstruction group. Surgical outcomes were evaluated by postoperative symptom improvement and patency of the rhinostomy under nasal endoscopic exam. The epiphora was improved in 84.2% of the silicone stent group and 81.8% of the non-silicone stent group. Categorized by the level of obstruction, in common canalicular obstruction, the success rate was 84.5% (11/13) in the silicone stent group and 57.1% (4/7) in the no stent group. In NLD obstruction, the success rate was 83.0% (5/6) in the silicone stent group and 93.3% (14/15) in the no stent group.

Temporary use of silicone stents for severe airway stenosis in untreated malignant lymphoma.

PubMed

Oki, Masahide; Saka, Hideo

2013-01-01

Airway stenting has become a popular method for palliation of airway stenosis; however, little has been reported about their use for patients with malignant lymphoma that occasionally causes a life-threatening condition. The aim of the study was to evaluate the efficacy and safety of airway stenting in chemoradiotherapy naive patients with severe airway stenosis due to malignant lymphoma. Patients who underwent airway stent placement from April 2007 to July 2011 in a single center were retrospectively reviewed. All stenting procedures were performed using rigid and flexible bronchoscopes under general anesthesia. We performed 174 airway stenting procedures (silicone stents in 154 procedures and metallic in 20 procedures) for 150 patients during the study period. Of the patients, 7 had untreated malignant lymphomas (4 diffuse large B-cell lymphomas, 2 lymphoblastic lymphomas, 1 mucosa-associated lymphoid tissue lymphoma). All patients underwent stenting using the silicone Y-stent (6 on the main carina and 1 on the primary right carina). Dyspnea was relieved immediately in 6 of 7 patients including the mechanically ventilated patient. Stents could be removed in all patients (median 90 d after stenting; range, 32 to 245 d) because of the tumor response to tumor-specific therapy. One granuloma formation and 1 mucus retention triggered the decision to remove the stents. Airway stenting using silicone stents is safe and effective in palliation of airway stenosis in patients with untreated malignant lymphoma, and permits postprocedural tumor-specific therapy. The response to tumor-specific therapy can be expected, and so removable stents should be selected.

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

Sun Zhonghua, E-mail: z.sun@curtin.edu.a; Chaichana, Thanapong

The purpose of the study was to investigate the hemodynamic effect of stent struts (wires) on renal arteries in patients with abdominal aortic aneurysms (AAAs) treated with suprarenal stent-grafts. Two sample patients with AAA undergoing multislice CT angiography pre- and postsuprarenal fixation of stent-grafts were selected for inclusion in the study. Eight juxtarenal models focusing on the renal arteries were generated from the multislice CT datasets. Four types of configurations of stent wires crossing the renal artery ostium were simulated in the segmented aorta models: a single wire crossing centrally, a single wire crossing peripherally, a V-shaped wire crossing centrally,more » and multiple wires crossing peripherally. The blood flow pattern, flow velocity, wall pressure, and wall shear stress at the renal arteries pre- and post-stent-grafting were analyzed and compared using a two-way fluid structure interaction analysis. The stent wire thickness was simulated with a diameter of 0.4, 1.0, and 2.0 mm, and hemodynamic analysis was performed at different cardiac cycles. The interference of stent wires with renal blood flow was mainly determined by the thickness of stent wires and the type of configuration of stent wires crossing the renal ostium. The flow velocity was reduced by 20-30% in most of the situations when the stent wire thickness increased to 1.0 and 2.0 mm. Of the four types of configuration, the single wire crossing centrally resulted in the highest reduction of flow velocity, ranging from 21% to 28.9% among three different wire thicknesses. Wall shear stress was also dependent on the wire thickness, which decreased significantly when the wire thickness reached 1.0 and 2.0 mm. In conclusion, our preliminary study showed that the hemodynamic effect of suprarenal stent wires in patients with AAA treated with suprarenal stent-grafts was determined by the thickness of suprarenal stent wires. Research findings in our study are useful for follow-up of patients treated with suprarenal stent-grafts to ensure long-term safety of the suprarenal fixation.« less

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

Krokidis, Miltiadis, E-mail: mkrokidis@hotmail.com; Fanelli, Fabrizio; Orgera, Gianluigi

The purpose of this study was to compare the clinical effectiveness of expanded polytetrafluoroethylene/fluorinated-ethylene-propylene (ePTFE/FEP)-covered stents with that of uncovered nitinol stents for the palliation of malignant jaundice caused by inoperable pancreatic head cancer. Eighty patients were enrolled in a prospective randomized study. Bare nitinol stents were used in half of the patients, and ePTFE/FEP-covered stents were used in the remaining patients. Patency, survival, complications, and mean cost were calculated in both groups. Mean patency was 166.0 {+-} 13.11 days for the bare-stent group and 234.0 {+-} 20.87 days for the covered-stent group (p = 0.007). Primary patency rates atmore » 3, 6, and 12 months were 77.5, 69.8, and 69.8% for the bare-stent group and 97.5, 92.2, and 87.6% for the covered-stent group, respectively. Mean secondary patency was 123.7 {+-} 22.5 days for the bare-stent group and 130.3 {+-} 21.4 days for the covered-stent group. Tumour ingrowth occurred exclusively in the bare-stent group in 27.5% of cases (p = 0.002). Median survival was 203.2 {+-} 11.8 days for the bare-stent group and 247.0 {+-} 20 days for the covered-stent group (p = 0.06). Complications and mean cost were similar in both groups. Regarding primary patency and ingrowth rate, ePTFE/FEP-covered stents have shown to be significantly superior to bare nitinol stents for the palliation of malignant jaundice caused by inoperable pancreatic head cancer and pose comparable cost and complications. Use of a covered stent does not significantly influence overall survival rate; nevertheless, the covered endoprosthesis seems to offer result in fewer reinterventions and better quality of patient life.« less

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.

Re-examining minimal luminal diameter relocation and quantitative coronary angiography--intravascular ultrasound correlations in stented saphenous vein grafts: methodological insights from the randomised RRISC trial.

PubMed

Semeraro, Oscar; Agostoni, Pierfrancesco; Verheye, Stefan; Van Langenhove, Glenn; Van den Heuvel, Paul; Convens, Carl; Van den Branden, Frank; Bruining, Nico; Vermeersch, Paul

2009-03-01

Angiographic parameters (such as late luminal loss) are common endpoints in drug-eluting stent trials, but their correlation with the neointimal process and their reliability in predicting restenosis are debated. Using quantitative coronary angiography (QCA) data (49 bare metal stent and 44 sirolimus-eluting stent lesions) and intravascular ultrasound (IVUS) data (39 bare metal stent and 34 sirolimus-eluting stent lesions) from the randomised Reduction of Restenosis In Saphenous vein grafts with Cypher stent (RRISC) trial, we analysed the "relocation phenomenon" of QCA-based in-stent minimal luminal diameter (MLD) between post-procedure and follow-up and we correlated QCA-based and IVUS-based restenotic parameters in stented saphenous vein grafts. We expected the presence of MLD relocation for low late loss values, as MLD can "migrate" along the stent if minimal re-narrowing occurs, while we anticipated follow-up MLD to be located close to post-procedural MLD position for higher late loss. QCA-based MLD relocation occurred frequently: the site of MLD shifted from post-procedure to follow-up an "absolute" distance of 5.8 mm [2.5-10.2] and a "relative" value of 29% [10-46]. MLD relocation failed to correlate with in-stent late loss (rho = 0.14 for "absolute" MLD relocation [p = 0.17], and rho=0.03 for "relative" relocation [p = 0.811). Follow-up QCA-based and IVUS-based MLD values well correlated in the overall population (rho = 0.76, p < 0.001), but QCA underestimated MLD on average 0.55 +/- 0.49 mm, and this was mainly evident for lower MLD values. Conversely, the location of QCA-based MLD failed to correlate with the location of IVUS-based MLD (rho = 0.01 for "absolute" values--in mm [p = 0.911, rho = 0.19 for "relative" values--in % [p = 0.111). Overall, the ability of late loss to "predict" IVUS parameters of restenosis (maximum neointimal hyperplasia diameter, neointimal hyperplasia index and maximum neointimal hyperplasia area) was moderate (rho between 0.46 and 0.54 for the 3 IVUS parameters). These findings suggest the need for a critical re-evaluation of angiographic parameters (such as late loss) as endpoints for drug-eluting stent trials and the use of more precise techniques to describe accurately and properly the restenotic process.

Urinary tract infections associated with ureteral stents: A Review.

PubMed

Liaw, A; Knudsen, B

2016-10-01

We review the literature on infections associated with ureteral stents and new technologies aimed at preventing them. Ureteral stent placement is one of the most common urologic procedures, but carries a comparatively high morbidity. Infection is one of the most common stent-associated morbidities. Several new stent materials and coatings have been proposed and tested to reduce stent-associated infections. We review the current methods of preventing bacterial infection, including antibiotic prophylaxis and minimising dwell time. We look at the science underlying infection and biofilm formation on stents. Several new stent materials and coatings are described, as well as the studies underlying their mechanism of action. While many promising ideas for new stent coatings and materials have been tested, no significant improvement to current polyurethane stent technology is commonly available or used. The basic principles of antibiotic prophylaxis at time of insertion, avoiding contamination, and minimising dwell times remain the best methods to prevent stent-associated infections.

Safety and efficacy of self-expandable metal stents for obstructive proximal and distal large bowel cancer.

PubMed

Mitra, V; Hu, M; Majumdar, D; Krishnan, V; Chaudhury, B; Hancock, J; Dwarakanath, D

2017-03-01

Self-expandable metal stents are often used to treat obstructive large bowel cancers. This study assessed the safety and efficacy of colonic stent insertion carried out in a district general hospital. Methods A retrospective review was carried out between 1 January 2007 and 28 February 2014 to identify patients who underwent stent insertion for malignant colorectal obstruction. Results Seventy-five patients (median age 75.2 years, 70.6% male) with primary colorectal cancer underwent stent insertion - 53 underwent semi-elective self-expanded metal stent insertion (for subacute bowel obstruction) and 22 had emergency stent inserted (for acute bowel obstruction). The majority (88%) had self-expanded metal stents inserted for palliation. Technical and clinical success rates were 98.7% and 91.2%, respectively. One patient had stent-related perforation; there was no procedure-related mortality. Conclusion This study shows that self-expanded metal stent insertion in malignant colorectal obstruction is safe and effective and can be successfully delivered in a district general hospital with high technical and clinical success rates.

Endovascular treatment of wide-neck intracranial aneurysms using a microcatheter protective technique: results and outcomes in 75 aneurysms.

PubMed

Lee, J Y; Seo, J H; Cho, Y D; Kang, H-S; Han, M H

2011-05-01

The microcatheter protective technique positions an additional microcatheter in the parent or side-branching artery to protect it during coil embolization. The purpose of this study was to describe this method and to evaluate its efficacy and safety as an alternative to a multiple-microcatheter or balloon- or stent-assisted technique for wide-neck aneurysms. A retrospective review of 74 patients (43 women; mean age, 59.6 years) with 75 wide-neck aneurysms treated with the microcatheter protective technique between January 2003 and April 2010 was performed. Immediate postembolization angiograms were evaluated by using a conventional angiographic scale, and clinical evaluation was performed by using the GOS. Clinical and imaging follow-up were available in 57 (76%) patients, with a mean of 14.7 months. Postembolization angiograms demonstrated total occlusion in 45 of 75 (60%) aneurysms, a neck remnant in 17 (22.7%), and body filling in 13 (17.3%). The technique-related complication rate was 17.4% (13/75), and the procedural-related morbidity rate was 1.3% (1/74). All patients, except 3 complicated cases with a GOS of <4, had a GOS of 5 at the end of the study period. Of the 57 aneurysms with follow-up, recanalization developed in 5 (8.8%) aneurysms, and 3 (5.3%) cases of major recanalization were re-treated endovascularly. The microcatheter protective technique is feasible and safe for coil embolization of wide-neck aneurysms, especially in cases that are not suitable for multiple catheter or balloon- or stent-assisted techniques.

Risk of stent thrombosis among bare-metal stents, first-generation drug-eluting stents, and second-generation drug-eluting stents: results from a registry of 18,334 patients.

PubMed

Tada, Tomohisa; Byrne, Robert A; Simunovic, Iva; King, Lamin A; Cassese, Salvatore; Joner, Michael; Fusaro, Massimiliano; Schneider, Simon; Schulz, Stefanie; Ibrahim, Tareq; Ott, Ilka; Massberg, Steffen; Laugwitz, Karl-Ludwig; Kastrati, Adnan

2013-12-01

This study sought to compare the risk of stent thrombosis among patients treated with bare-metal stents (BMS), first-generation drug-eluting stents (G1-DES), and second-generation drug-eluting stents (G2-DES) for a period of 3 years. In patients undergoing coronary stenting, there is a scarcity of long-term follow-up data on cohorts large enough to compare rates of stent thrombosis across the stent generations. A total of 18,334 patients undergoing successful coronary stent implantation from 1998 to 2011 at 2 centers in Munich, Germany, were included in this study. Patients were stratified into 3 groups according to treatment with BMS, G1-DES, and G2-DES. The cumulative incidence of definite stent thrombosis at 3 years was 1.5% with BMS, 2.2% with G1-DES, and 1.0% with G2-DES. On multivariate analysis, G1-DES compared with BMS showed a significantly higher risk of stent thrombosis (odds ratio [OR]: 2.05; 95% confidence interval [CI]: 1.47 to 2.86; p < 0.001). G2-DES were associated with a similar risk of stent thrombosis compared with BMS (OR: 0.82; 95% CI: 0.56 to 1.19; p = 0.30). Beyond 1 year, the risk of stent thrombosis was significantly increased with G1-DES compared with BMS (OR: 4.72; 95% CI: 2.01 to 11.1; p < 0.001), but not with G2-DES compared with BMS (OR: 1.01; 95% CI: 0.32 to 3.25; p = 0.98). In a large cohort of unselected patients undergoing coronary stenting, compared with BMS, there was a significant excess risk of stent thrombosis at 3 years with G1-DES, driven by an increased risk of stent thrombosis events beyond 1 year. G2-DES were associated with a similar risk of stent thrombosis compared with BMS. Copyright © 2013 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Lumen apposing metal stents for pancreatic fluid collections: Recognition and management of complications.

PubMed

DeSimone, Michael L; Asombang, Akwi W; Berzin, Tyler M

2017-09-16

For patients recovering from acute pancreatitis, the development of a pancreatic fluid collection (PFC) predicts a more complex course of recovery, and introduces difficult management decisions with regard to when, whether, and how the collection should be drained. Most PFCs resolve spontaneously and drainage is indicated only in pseudocysts and walled-off pancreatic necrosis when the collections are causing symptoms and/or local complications such as biliary obstruction. Historical approaches to PFC drainage have included surgical (open or laparoscopic cystgastrostomy or pancreatic debridement), and the placement of percutaneous drains. Endoscopic drainage techniques have emerged in the last several years as the preferred approach for most patients, when local expertise is available. Lumen-apposing metal stents (LAMS) have recently been developed as a tool to facilitate potentially safer and easier endoscopic drainage of pancreatic fluid collections, and less commonly, for other indications, such as gallbladder drainage. Physicians considering LAMS placement must be aware of the complications most commonly associated with LAMS including bleeding, migration, buried stent, stent occlusion, and perforation. Because of the patient complexity associated with severe pancreatitis, management of pancreatic fluid collections can be a complex and multidisciplinary endeavor. Successful and safe use of LAMS for patients with pancreatic fluid collections requires that the endoscopist have a full understanding of the potential complications of LAMS techniques, including how to recognize and manage expected complications.

Percutaneous stent placement for the treatment of malignant biliary obstruction: nitinol versus elgiloy stents.

PubMed

Zurstrassen, Charles Edouard; Bitencourt, Almir Galvão Vieira; Guimaraes, Marcos Duarte; Cavalcante, Aline Cristine Barbosa Santos; Tyng, Chiang Jeng; Amoedo, Mauricio Kauark; Matsushita Junior, João Paulo Kawaoka; Szklaruk, Janio; Marchiori, Edson; Chojniak, Rubens

2017-01-01

This study aimed to compare two self-expanding stents, a nitinol stent and an elgiloy stent, both placed percutaneously, in terms of their efficacy in palliating inoperable malignant biliary obstruction. We retrospectively investigated 99 patients with unresectable malignant biliary obstruction treated with percutaneous placement of a self-expanding metallic stent at our institution between May 2007 and January 2010. Serum bilirubin and liver enzyme levels were measured before and 30 days after stenting. For all procedures using elgiloy or nitinol stents, stent occlusion and patient survival rates were calculated using Kaplan-Meyer analysis. All of the patients showed clinical improvement after stent placement, with no difference between the two groups. In both groups, the occlusion-free survival rate was 67% at 30 days, 37% at 90 days, 25% at 180 days, and 10% at 360 days, with no significant difference in relation to the type of stent. The two stents evaluated showed comparable efficacy for the percutaneous treatment of unresectable biliary malignancy, with good clinical results.

Treatment of symptomatic carotid stenosis: carotid stent placement versus endarterectomy.

PubMed

Alqadri, Syeda L; Qureshi, Adnan I

2013-08-01

The mainstay of treatment options for symptomatic carotid stenosis is focused around medical management, carotid endarterectomy, and carotid angioplasty and stent placement. The International Carotid Stenting Study (ICSS), also called Carotid and Vertebral Artery Transluminal Angioplasty Study 2 (CAVATAS 2), the Stent-Supported Percutaneous Angioplasty of the Carotid Artery Versus Endarterectomy (SPACE) trial, the Endarterectomy Versus Angioplasty in Patients with Symptomatic Severe Carotid Stenosis (EVA-3S) trial, the Stenting and Angioplasty with Protection in Patients at High Risk for Endarterectomy (SAPPHIRE) trial, and the Carotid Revascularization Endarterectomy Versus Stenting Trial (CREST) were five major trials which compared carotid endarterectomy and carotid angioplasty and stent placement. We review the results of the trials and incorporation of the results into clinical decision making.

Treatment of gastric leaks with coated self-expanding stents after sleeve gastrectomy.

PubMed

Serra, Carlos; Baltasar, Aniceto; Andreo, Luis; Pérez, Nieves; Bou, Rafael; Bengochea, Marcelo; Chisbert, Juan José

2007-07-01

Duodenal switch (DS) is one of the most effective techniques for the treatment of morbid obesity and its co-morbidities, with mortality rate <1%, but with 9.4% morbidity rates (6.5% due to leaks). In our experience, leaks of the staple-line after sleeve gastrectomy (SG) are the most frequent sites of fistula formation and conservative treatment usually takes a long time. We present our experience in the treatment of gastric leaks with coated self-expandable stents (CSES). 6 patients had gastric leaks at the gastroesophageal (GE) junction after SG or DS. One patient had a symptomatic gastro-bronchial fistula. Stents were placed by the interventional radiologist under fluoroscopic control and removed endoscopically. In one case, we used an uncoated Wallstent. In two patients, percutaneous microcoil embolization of the fistula was added. The patient treated with the Wallstent required a total gastrectomy 6 months after placement of the uncovered stent. In the other 5 patients, coated stents were successfully removed and the gastric leaks completely sealed. CSES are proposed as an alternative therapeutic option for the management of GE junction leaks in bariatric surgery with good results in terms of morbidity and survival.

On the Mechanical Properties and Microstructure of Nitinol forBiomedical Stent Applications

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

Robertson, Scott W.

2006-01-01

This dissertation was motivated by the alarming number of biomedical device failures reported in the literature, coupled with the growing trend towards the use of Nitinol for endovascular stents. The research is aimed at addressing two of the primary failure modes in Nitinol endovascular stents: fatigue-crack growth and overload fracture. The small dimensions of stents, coupled with their complex geometries and variability among manufacturers, make it virtually impossible to determine generic material constants associated with specific devices. Instead, the research utilizes a hybrid of standard test techniques (fracture mechanics and x-ray micro-diffraction) and custom-designed testing apparatus for the determination ofmore » the fracture properties of specimens that are suitable representations of self-expanding Nitinol stents. Specifically, the role of texture (crystallographic alignment of atoms) and the austenite-to-martensite phase transformation on the propagation of cracks in Nitinol was evaluated under simulated body conditions and over a multitude of stresses and strains. The results determined through this research were then used to create conservative safe operating and inspection criteria to be used by the biomedical community for the determination of specific device vulnerability to failure by fracture and/or fatigue.« less

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

Stent thrombosis with drug-eluting and bare-metal stents: evidence from a comprehensive network meta-analysis.

PubMed

Palmerini, Tullio; Biondi-Zoccai, Giuseppe; Della Riva, Diego; Stettler, Christoph; Sangiorgi, Diego; D'Ascenzo, Fabrizio; Kimura, Takeshi; Briguori, Carlo; Sabatè, Manel; Kim, Hyo-Soo; De Waha, Antoinette; Kedhi, Elvin; Smits, Pieter C; Kaiser, Christoph; Sardella, Gennaro; Marullo, Antonino; Kirtane, Ajay J; Leon, Martin B; Stone, Gregg W

2012-04-14

The relative safety of drug-eluting stents and bare-metal stents, especially with respect to stent thrombosis, continues to be debated. In view of the overall low frequency of stent thrombosis, large sample sizes are needed to accurately estimate treatment differences between stents. We compared the risk of thrombosis between bare-metal and drug-eluting stents. For this network meta-analysis, randomised controlled trials comparing different drug-eluting stents or drug-eluting with bare-metal stents currently approved in the USA were identified through Medline, Embase, Cochrane databases, and proceedings of international meetings. Information about study design, inclusion and exclusion criteria, sample characteristics, and clinical outcomes was extracted. 49 trials including 50,844 patients randomly assigned to treatment groups were analysed. 1-year definite stent thrombosis was significantly lower with cobalt-chromium everolimus eluting stents (CoCr-EES) than with bare-metal stents (odds ratio [OR] 0·23, 95% CI 0·13-0·41). The significant difference in stent thrombosis between CoCr-EES and bare-metal stents was evident as early as 30 days (OR 0·21, 95% CI 0·11-0·42) and was also significant between 31 days and 1 year (OR 0·27, 95% CI 0·08-0·74). CoCr-EES were also associated with significantly lower rates of 1-year definite stent thrombosis compared with paclitaxel-eluting stents (OR 0·28, 95% CI 0·16-0·48), permanent polymer-based sirolimus-eluting stents (OR 0·41, 95% CI 0·24-0·70), phosphorylcholine-based zotarolimus-eluting stents (OR 0·21, 95% CI 0·10-0·44), and Resolute zotarolimus-eluting stents (OR 0·14, 95% CI 0·03-0·47). At 2-year follow-up, CoCr-EES were still associated with significantly lower rates of definite stent thrombosis than were bare-metal (OR 0·35, 95% CI 0·17-0·69) and paclitaxel-eluting stents (OR 0·34, 95% CI 0·19-0·62). No other drug-eluting stent had lower definite thrombosis rates compared with bare-metal stents at 2-year follow-up. In randomised studies completed to date, CoCr-EES has the lowest rate of stent thrombosis within 2 years of implantation. The finding that CoCr-EES also reduced stent thrombosis compared with bare-metal stents, if confirmed in future randomised trials, represents a paradigm shift. The Cardiovascular Research Foundation. Copyright © 2012 Elsevier Ltd. All rights reserved.

Endovascular Techniques for the Treatment of Renal Artery Aneurysms

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

Elaassar, Omar, E-mail: elaassaro@yahoo.com; Auriol, Julien; Marquez, Romero

2011-10-15

Purpose: Our goal was to analyze the indications and limitations of the different percutaneous endovascular approaches reported for the treatment of renal artery aneurysms (RAAs) and to develop a scientific approach for optimum selection of treatment strategy of RAAs through analyzing our experience and reviewing available literature. Methods: This retrospective study was designed to evaluate the treatment and follow-up of 13 consecutive patients who presented with 13 RAAs by using a variety of endovascular interventional techniques. Different combinations of coil embolization, liquid embolization, stenting, and stent-graft exclusion were used in correlation with variable-specific aneurysm criteria. Results: All patients were successfullymore » treated with no significant short- or long-term complications. Patients were followed for an average period of 43 (range 13-103) months. Conclusions: Ten different determinants were found to affect our decision making: shape, size, neck, position of aneurysm on artery, branches arising, artery involved, condition of the artery, age, general condition of the patient, and renal function.« less

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.

Utility of intravascular ultrasound examination during carotid stenting.

PubMed

Joan, M Mellado; Moya, B Gómez; Agustí, F Pañella; Vidal, R García; Arjona, Y Abril; Alija, M P Fariñas; Paredero, V Martín

2009-01-01

Intravascular ultrasound (IVUS) examination may provide useful information during endovascular procedures. However, its actual clinical utility for carotid stenting remains unclear. We evaluated the usefulness of IVUS as a complementary tool during endovascular procedures in the carotid arteries and its impact on the modification of the therapeutic strategy. Between April 2006 and April 2007, 18 symptomatic patients (nine with transient ischemic attack, nine with stroke) underwent angioplasty and stenting of >70% stenosis of the internal carotid artery (ICA). Target lesions were identified with preoperative duplex scanning and further confirmed at angiography. Intraoperative IVUS examination was performed in all patients. Multilevel measurement of the artery as well as virtual histology images, before and after stenting, were obtained. The technique was 100% successful. There were no complications at the femoral puncture site and no neurological or other events. Compared with angiography, IVUS findings showed an average arterial diameter that was greater than 1.64+/-0.22mm. Based on virtual histology information, endovascular treatment was excluded in two patients and carotid endarterectomy was performed. Type or size of the stent was modified after IVUS examination in eight cases. IVUS examination provides complementary information to that obtained using conventional diagnostic procedures. It may be useful for characterizing the composition and measurement of the target lesion, choosing the type and size of the stent, and evaluating the results after the procedure.

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.

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.

Clinical results from first use of prostate stent as fiducial for radiotherapy of prostate cancer.

PubMed

Carl, Jesper; Nielsen, Jane; Holmberg, Mats; Larsen, Erik Hoejkjaer; Fabrin, Knud; Fisker, Rune V

2011-05-01

A clinical feasibility study using a removable prostate stent as fiducial for image-guided radiotherapy (IGRT) of localized prostate cancer (PC). The study included patients with local or locally advanced PC. The clinical target volume (CTV) was outlined on magnetic resonance (MR) images co-registered to planning computer tomography (CT) images. Daily online IGRT was delivered using the stent as fiducial. Risk of migration was estimated using multiple MR. Acute urinary toxicity was scored using the international prostate symptom score (IPSS). Late gastro-intestinal (GI) and genito-urinary (GU) toxicity was scored using the Radio Therapy Oncology Group (RTOG) score, biochemical failure (BF) was defined as an elevation of prostate specific antigen (PSA) above nadir plus 2 ng/ml after radiotherapy. One hundred men were enrolled in the study. Ninety completed radiotherapy with the stent as fiducial. No migration of the stent was seen, but three cases of dislocation of the stent to the bladder were observed. Acute urinary toxicity based on IPSS was comparable to toxicity in patients who had gold markers (GM) as fiducials. Removal of the stent was associated with a high frequency of urinary retention. Late GI and GU toxicity and BF were comparable to those of other studies, but longer observation time is needed. This study reports the first clinical results of using a prostate stent as fiducial. No migration of the stent observed. Dislocation of the stent to the urinary bladder was observed in three cases, requiring removal of the stent and insertion of a new fiducial. Acute toxicity during radiotherapy evaluated from IPSS was comparable to toxicity in patients with GM. Removal of the stent was associated with a high frequency of post procedural urinary retention. Late toxicity and BF were comparable to those of other studies, though longer observation time is needed.

[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.

Increasing Efficacy of Thrombectomy by Using Digital Subtraction Angiography to Confirm Stent Retriever Clot Integration

PubMed Central

Simon, Scott; Cooke, Jonathon

2016-01-01

Physicians performing thrombectomy for acute stroke have had increasing success as thrombectomy-specific devices have continued to evolve. As the devices evolve, so too must the techniques. The current generation of stent retriever thrombectomy devices requires five minutes of dwell time, regardless of the particularities of the case. We have noticed the presence of flow through the stent immediately prior to removal portends a lower chance of successful thrombus retrieval than when no flow is seen, regardless of dwell time. We hypothesize that interventionalists can use the presence or absence of flow to predict adequacy of seating time and decrease the number of deployments per case. This could significantly decrease time to recanalization by avoiding time-consuming, unsuccessful pulls. This is a technical report of a few cases of stent retriever thrombectomy. We propose using post-deployment digital subtraction angiography to confirm thrombus-device integration and increase the chance of thrombus removal. PMID:27182473

Outcomes after bronchoscopic procedures for primary tracheobronchial amyloidosis: retrospective study of 6 cases.

PubMed

Alloubi, Ihsan; Thumerel, Matthieu; Bégueret, Hugues; Baste, Jean-Marc; Velly, Jean-François; Jougon, Jacques

2012-01-01

Respiratory amyloidosis is a rare disease which refers to localized aberrant extracellular protein deposits within the airways. Tracheobronchial amyloidosis (TBA) refers to the deposition of localized amyloid deposits within the upper airways. Treatments have historically focused on bronchoscopic techniques including debridement, laser ablation, balloon dilation, and stent placement. We present the outcomes after rigid bronchoscopy to remove the amyloid protein causing the airway obstruction in 6 cases of tracheobronchial amyloidosis. This is the first report of primary diffuse tracheobronchial amyloidosis in our department; clinical features, in addition to therapy in the treatment of TBA, are reviewed. This paper shows that, in patients with TBA causing airway obstruction, excellent results can be obtained with rigid bronchoscopy and stenting of the obstructing lesion.

Supera self-expanding stents for endovascular treatment of femoropopliteal disease: a review of the clinical evidence

PubMed Central

Bishu, Kalkidan; Armstrong, Ehrin J

2015-01-01

Femoropopliteal lesions account for a significant proportion of endovascular interventions for peripheral artery disease in patients with disabling claudication or chronic limb ischemia. The femoropopliteal artery crosses two joint structures (hip and knee joints) and courses through the muscular adductor canal in the thigh, which places the artery at increased biomechanical stress. There is a critical need for stent platforms with a reduced risk of stent fracture while maintaining patency during long-term follow-up. The Supera peripheral stent system has a braided nickel–titanium alloy stent designed to withstand the unique stressors along the course of the femoropopliteal artery. This design may be associated with improved patency in association with reduced stent fracture rates on short- and medium-term follow-up. Further studies, including randomized controlled studies, comparing the Supera interwoven nickel–titanium alloy stent system with other stent platforms and angioplasty alone are needed. PMID:26203255

Stent fracture in the superficial femoral and proximal popliteal arteries: literature summary and economic impacts.

PubMed

Neil, Nancy

2013-06-01

To summarize available evidence regarding stent fracture in the femoropopliteal region. We searched PubMed, 2000-2011, using MeSH search terms "stents," "popliteal artery," and "femoral artery." We identified 29 original studies reporting 0% to 65% incidence of stent fracture. Fracture-related repeat revascularization could be avoided in the absence of device failure. Recently published data suggest that even a 5% rate of fracture-related reintervention would generate $118.4 million in health care cost in the United States. These excess procedures would also result in major complications and deaths that might have been avoided in the absence of stent fracture. Reported incidence and clinical relevance of femoropopliteal stent fractures vary across studies. Stent fracture may lead to repeat revascularization. These reinterventions create considerable--and potentially avoidable--economic burden for patients and payers. Further, these costs are effectively invisible wherever stent fractures are not systematically documented as the reason for reintervention.

Comparison of Flow Characteristics of Novel Three-Dimensional Printed Ureteral Stents Versus Standard Ureteral Stents in a Porcine Model.

PubMed

Del Junco, Michael; Yoon, Renai; Okhunov, Zhamshid; Abedi, Garen; Hwang, Christina; Dolan, Benjamin; Landman, Jaime

2015-09-01

We compared the flow characteristics of novel three-dimensional (3D) printed ureteral stents with four conventional double-pigtail stents in an ex vivo porcine model. In six ex vivo porcine urinary systems with kidneys and ureters intact, we deployed a 5F occlusion catheter in an interpolar calix. We tested each system with antegrade irrigation with a 0.9% saline bag placed 35 cm above the renal pelvis. We evaluated four standard stents (6F Universa® Soft, 7F Percuflex,™ 7/10F Applied Endopyelotomy, 8.5F Filiform Double Pigtail) and compared them with a 9F 3D printed prototype stent. For each stent, we measured the total, extraluminal, and intraluminal flow rates. The mean total flow rates for 3D printed stents were significantly higher than the 6F, 7F, and 7/10F stents (P<0.05). No significant difference was seen in the total flow rate for the 3D printed stent and the 8.5F stent. The mean extraluminal flow rates for the 3D stents were similar to those of 7F stents, but significantly lower than 6F stents (P<0.001) and 8.5F stents (P<0.05) and higher than 7/10F stents (P<0.001). The mean intraluminal flow rates for the 3D printed stents were significantly higher than the 6F, 7F, 7/10F, and 8.5F stents (P<0.05). In this pilot study, 3D printed stents manifested a mean total flow rate comparable to the flow rates of contemporary stents. Continued advances in technology and material may permit functionally feasible 3D printed ureteral stents.

Development and evaluation of a centralised computerised registry for ureteric stents: completing the audit cycle.

PubMed

Davis, N F; Murray, G; O'Connor, T; Browne, C; MacCraith, E; Galvin, D; Mulvin, D; Quinlan, D; Lennon, G

2017-11-01

A forgotten ureteric stent may result in severe renal impairment leading to nephrectomy. To compare the effectiveness of a centralised computerised registry for monitoring ureteric stent activity with a previously established theatre stent logbook system. This prospective audit was performed in two 9-monthly intervals. During the first interval, insertion/removal of a ureteric stent was documented in a specific theatre stent logbook. In the second interval, an electronic centralised computerised registry was developed to document insertion/removal of a ureteric stent onto an accessible hospital server. A computerised traffic-light system was also developed to identify patients with an indwelling stent for >3 months. The primary outcome variable was the number of prolonged indwelling ureteric stents in both groups. During the first time interval, 188 ureteric stents were inserted and 182 (96%) were removed or changed. Six (4%) patients underwent insertion of a ureteric stent for a prolonged period of time (>6 months). This subgroup required complex endourological intervention for stent removal due to encrustation. During the second time interval, 157 ureteric stents were inserted and all patients had their stent removed or changed within 6 months. No patients in this group were lost to follow-up. This study demonstrates that a centralised computerised ureteric stent registry is superior to a conventional logbook for monitoring ureteric stent activity. We propose the introduction a centralised nationalised ureteric stent registry for eliminating the potential for prolonged or forgotten ureteric stents.