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Sample records for paclitaxel-eluting stent implantation

  1. Late acute thrombosis after paclitaxel eluting stent implantation

    PubMed Central

    Liistro, F; Colombo, A

    2001-01-01

    Late (more than six months) total occlusion after coronary stenting is a progressive phenomenon occurring in approximately 4% of patients, leading to acute myocardial infarction in less than 0.5%. The process must be related to severe and progressive intimal hyperplasia. In patients receiving coronary stenting with simultaneous brachytherapy, late total occlusion has been reported at a higher rate and to be related to stent thrombosis rather than intimal hyperplasia. Late total occlusion presenting with an acute clinical event seven months after the implantation of a paclitaxel drug eluting stent is reported. The occlusion developed soon after the interruption of ticlopidine treatment, suggesting that the event had a thrombotic genesis and that the risk is not confined to the first six month period.


Keywords: paclitaxel eluting stent; late thrombosis PMID:11514475

  2. Safety and efficacy of a novel iopromide-based paclitaxel-eluting balloon following bare metal stent implantation in rabbit aorta abdominalis

    PubMed Central

    Zhu, Zhengbin; Han, Hui; Zhu, Jinzhou; Zhang, Jing; Du, Run; Ni, Jingwei; Ying, Chen; An, Xuanqi; Zhang, Ruiyan

    2015-01-01

    BACKGROUND: Drug-eluting balloons (DEB) may be promising technology for treating atherosclerotic arterial disease. In fact, several DEBs have been clinically available for the treatment of coronary in-stent restenosis (ISR), de novo coronary lesions, and peripheral artery disease. OBJECTIVE: We sought to elucidate the mechanism of action and in vivo safety and efficacy of a novel iopromide-based paclitaxel-eluting balloon. METHODS: In vitro cytotoxicity of a novel DEB on human umbilical vein endothelial cells (HUVECs) and in vivo pharmacokinetics of DEB in a rabbit aorta abdominalis were assessed. Then, bare metal stents (BMS) were implanted at both the proximal and distal sites of the rabbit aorta abdominalis. Stented vascular segments were immediately dilated with a bare balloon (control group) or the DEB (DEB group) randomly. Histological evaluation was performed in all treated segments at 28 days. Because paclitaxel is a tubulin-disrupting agent that binds preferentially to β-tubulin, we measured β-tubulin expression in aortal stent specimens via immunohistochemistry. RESULTS: We observed that DEB was compatible and could reduce neointimal hyperplasia compared with the bare balloon. Meanwhile, immunohistochemistry revealed that β-tubulin expression in the DEB group increased compared with the control group, indirectly suggesting successful uptake of paclitaxel by vessel walls after DEB dilation. CONCLUSIONS: The novel DEB is safe and has a favorable vascular healing response on neointimal hyperplasia. PMID:26484558

  3. Percutaneous radial intervention for complex bilateral renal artery stenosis using paclitaxel eluting stents.

    PubMed

    Granillo, Gastón A Rodriguez; van Dijk, Lukas C; McFadden, Eugène P; Serruys, Patrick W

    2005-01-01

    Techniques used in the coronary circulation may be useful in peripheral intervention. We report a case of bilateral renal artery stenosis treated via a radial approach by direct stenting with distal protection at a right ostial lesion and modified crush stenting at a left renal bifurcation lesion using paclitaxel-eluting stents.

  4. Neointimal tissue healing patterns after paclitaxel-eluting balloon treatment of in-stent restenosis: optical coherence tomography and intravascular ultrasound insights.

    PubMed

    Sandoval, Jorge; Medina, Miguel; Alfonso, Fernando

    2012-10-01

    An 80-year-old patient presented with severe in-stent restenosis of an everolimus-eluting stent implanted in the left anterior descending coronary artery 3 years previously. We obtained good angiographic result after paclitaxel-eluting balloon dilation. However, on optical coherence tomography (OCT), multiple, angiographically silent, in-stent, and edge-related dissections were readily recognized. Intravascular ultrasound (IVUS) revealed residual neointima with minor disruptions. At 9-month follow-up, an excellent angiographic result was demonstrated with complete resolution of the stent-related dissections on OCT. IVUS and OCT confirmed complete neointimal healing with a larger lumen. This case illustrates the value of OCT and IVUS to provide unique insights on the pathophysiological mechanisms and healing patterns of paclitaxel-eluting balloon treatment of in-stent restenosis.

  5. Twelve-Month Results From the MAJESTIC Trial of the Eluvia Paclitaxel-Eluting Stent for Treatment of Obstructive Femoropopliteal Disease

    PubMed Central

    Müller-Hülsbeck, Stefan; Keirse, Koen; Zeller, Thomas; Schroë, Herman; Diaz-Cartelle, Juan

    2016-01-01

    Purpose: To report the 12-month results of the MAJESTIC clinical study of the self-expanding Eluvia paclitaxel-eluting stent in the treatment of femoropopliteal lesions. Methods: The prospective, single-arm, multicenter trial (clinicaltrials.gov identifier NCT01820637) enrolled 57 patients (mean age 69±9 years; 47 men) with chronic lower limb ischemia referable to de novo or restenotic lesions in the native superficial femoral and/or proximal popliteal arteries. A third of the patients had diabetes. Mean lesion length was 70.8±28.1 mm, and diameter stenosis was 86.3%±16.2%; 26 (46%) lesions were occluded. Primary patency was defined as duplex ultrasound peak systolic velocity ratio ≤2.5 and the absence of target lesion revascularization (TLR) or bypass. Major adverse events (MAEs) included all-cause death through 1 month and target limb major amputation and TLR through 12 months. Results: All 57 patients had a single Eluvia stent implanted, employing pre- and postdilation in 93% (53/57) and 95% (54/57) of cases, respectively. Technical success was 97% (55/57; 2 failures due to residual stenosis >30%). At 12 months, primary patency was 96% (49/51) and the MAE rate was 4% (2/53); both MAEs were TLRs. No stent fractures were identified. There were no major amputations. One death occurred 368 days postprocedure, unrelated to the device or procedure. Improvements in the Rutherford category were sustained through 1 year, with 81% (43/53) exhibiting no symptoms (category 0) and 13% (7/53) presenting with mild claudication (category 1). Mean ABI improved from 0.73±0.22 at baseline to 1.02±0.20 at 12 months. Conclusion: MAJESTIC results showed that patients whose femoropopliteal arteries were treated with the Eluvia drug-eluting stent sustained high patency and low MAE rates through 12 months. PMID:27193308

  6. A Budget Impact Model for Paclitaxel-eluting Stent in Femoropopliteal Disease in France

    SciTech Connect

    De Cock, Erwin; Sapoval, Marc; Julia, Pierre; Lissovoy, Greg de; Lopes, Sandra

    2013-04-15

    The Zilver PTX drug-eluting stent (Cook Ireland Ltd., Limerick, Ireland) represents an advance in endovascular treatments for atherosclerotic superficial femoral artery (SFA) disease. Clinical data demonstrate improved clinical outcomes compared to bare-metal stents (BMS). This analysis assessed the likely impact on the French public health care budget of introducing reimbursement for the Zilver PTX stent. A model was developed in Microsoft Excel to estimate the impact of a progressive transition from BMS to Zilver PTX over a 5-year horizon. The number of patients undergoing SFA stenting was estimated on the basis of hospital episode data. The analysis from the payer perspective used French reimbursement tariffs. Target lesion revascularization (TLR) after primary stent placement was the primary outcome. TLR rates were based on 2-year data from the Zilver PTX single-arm study (6 and 9 %) and BMS rates reported in the literature (average 16 and 22 %) and extrapolated to 5 years. Net budget impact was expressed as the difference in total costs (primary stenting and reinterventions) for a scenario where BMS is progressively replaced by Zilver PTX compared to a scenario of BMS only. The model estimated a net cumulative 5-year budget reduction of Euro-Sign 6,807,202 for a projected population of 82,316 patients (21,361 receiving Zilver PTX). Base case results were confirmed in sensitivity analyses. Adoption of Zilver PTX could lead to important savings for the French public health care payer. Despite higher initial reimbursement for the Zilver PTX stent, fewer expected SFA reinterventions after the primary stenting procedure result in net savings.

  7. A polymer-free Paclitaxel eluting coronary stent: effects of solvents, drug concentrations and coating methods.

    PubMed

    Lamichhane, Sujan; Gallo, Annemarie; Mani, Gopinath

    2014-06-01

    Some polymer coatings used in drug-eluting stents (DES) cause adverse reactions. Hence, the use of self-assembled monolayers (SAMs) as a polymer-free platform to deliver an anti-proliferative drug (paclitaxel-PAT) from 2D metal substrates was previously demonstrated. In this study, we optimized the PAT coating on SAMs coated 3D coronary stents. For the optimization process, we investigated the effects of solvents (ethanol, DMSO, and their mixtures), drug concentrations (2, 3, 4, 8, and 12 mg/mL) in the coating solution, and coating methods (dip and spray) on PAT deposition. A solvent mixture of 75:25 v/v Et-OH:DMSO was determined to be the best for obtaining smooth and homogenous PAT coating. PAT coated stents prepared using 8 mg/mL and 3 mg/mL concentrations of PAT by dip and spray coating methods, respectively, were optimal in terms of carrying adequate drug doses (0.35 µg/mm(2) for dipping and 0.76 µg/mm(2) for spraying) as well as negligible defects observed in the coating. PAT was successfully released from SAMs coated stents in a biphasic manner with an initial burst followed by a sustained release for up to 10 weeks. Thus, this study sheds light on the effects of solvents, drug concentrations, and coating methods on preparing a polymer-free DES. PMID:24705673

  8. Durable Clinical Effectiveness With Paclitaxel-Eluting Stents in the Femoropopliteal Artery

    PubMed Central

    Ansel, Gary M.; Jaff, Michael R.; Ohki, Takao; Saxon, Richard R.; Smouse, H. Bob; Machan, Lindsay S.; Snyder, Scott A.; O’Leary, Erin E.; Ragheb, Anthony O.; Zeller, Thomas

    2016-01-01

    Background— This randomized controlled trial evaluated clinical durability of Zilver PTX, a paclitaxel-coated drug-eluting stent (DES), for femoropopliteal artery lesions. Outcomes compare primary DES versus percutaneous transluminal angioplasty (PTA), overall DES (primary and provisional) versus standard care (PTA and provisional Zilver bare metal stent [BMS]), and provisional DES versus provisional BMS. Methods and Results— Patients with symptomatic femoropopliteal artery disease were randomly assigned to DES (n=236) or PTA (n=238). Approximately 91% had claudication; 9% had critical limb ischemia. Patients experiencing acute PTA failure underwent secondary randomization to provisional BMS (n=59) or DES (n=61). The 1-year primary end points of event-free survival and patency showed superiority of primary DES in comparison with PTA; these results were sustained through 5 years. Clinical benefit (freedom from persistent or worsening symptoms of ischemia; 79.8% versus 59.3%, P<0.01), patency (66.4% versus 43.4%, P<0.01), and freedom from reintervention (target lesion revascularization, 83.1% versus 67.6%, P<0.01) for the overall DES group were superior to standard care in nonrandomized comparisons. Similarly, clinical benefit (81.8% versus 63.8%, P=0.02), patency (72.4% versus 53.0%, P=0.03), and freedom from target lesion revascularization (84.9% versus 71.6%, P=0.06) with provisional DES were improved over provisional BMS. These results represent >40% relative risk reduction for restenosis and target lesion revascularization through 5 years for the overall DES in comparison with standard care and for provisional DES in comparison with provisional BMS. Conclusions— The 5-year results from this large study provide long-term information previously unavailable regarding endovascular treatment of femoropopliteal artery disease. The Zilver PTX DES provided sustained safety and clinical durability in comparison with standard endovascular treatments. Clinical Trial

  9. A prospective evaluation of the safety and efficacy of the TAXUS Element paclitaxel-eluting coronary stent system for the treatment of de novo coronary artery lesions: Design and statistical methods of the PERSEUS clinical program

    PubMed Central

    2010-01-01

    Background Paclitaxel-eluting stents decrease angiographic and clinical restenosis following percutaneous coronary intervention compared to bare metal stents. TAXUS Element is a third-generation paclitaxel-eluting stent which incorporates a novel, thinner-strut, platinum-enriched metal alloy platform. The stent is intended to have enhanced radiopacity and improved deliverability compared to other paclitaxel-eluting stents. The safety and efficacy of the TAXUS Element stent are being evaluated in the pivotal PERSEUS clinical trials. Methods/Design The PERSEUS trials include two parallel studies of the TAXUS Element stent in single, de novo coronary atherosclerotic lesions. The PERSEUS Workhorse study is a prospective, randomized (3:1), single-blind, non-inferiority trial in subjects with lesion length ≤28 mm and vessel diameter ≥2.75 mm to ≤4.0 mm which compares TAXUS Element to the TAXUS Express2 paclitaxel-eluting stent system. The Workhorse study employs a novel Bayesian statistical approach that uses prior information to limit the number of study subjects exposed to the investigational device and thus provide a safer and more efficient analysis of the TAXUS Element stent. PERSEUS Small Vessel is a prospective, single-arm, superiority trial in subjects with lesion length ≤20 mm and vessel diameter ≥2.25 mm to <2.75 mm that compares TAXUS Element with a matched historical bare metal Express stent control. Discussion The TAXUS PERSEUS clinical trial program uses a novel statistical approach to evaluate whether design and metal alloy iterations in the TAXUS Element stent platform provide comparable safety and improved procedural performance compared to the previous generation Express stent. PERSEUS trial enrollment is complete and primary endpoint data are expected in 2010. PERSEUS Workhorse and Small Vessel are registered at http://www.clinicaltrials.gov, identification numbers NCT00484315 and NCT00489541. PMID:20059766

  10. Efficacies of the new Paclitaxel-eluting Coroflex Please™ Stent in percutaneous coronary intervention; comparison of efficacy between Coroflex Please™ and Taxus™ (ECO-PLEASANT) trial: study rationale and design

    PubMed Central

    Seo, Jae-Bin; Jeon, Hui-Kyung; Park, Kyung-Woo; Park, Jong-Seon; Bae, Jang-Ho; Kim, Sang-Wook; Moon, Keon-Woong; Choi, Jae-Woong; Lee, Sang-Gon; Chung, Woo-Young; Youn, Tae-Jin; Kim, Soo-Joong; Kim, Doo-Il; Kim, Byung-Ok; Hyon, Min-Su; Park, Keum-Soo; Cha, Tae-Joon; Hwang, Hweung-Kon; Hur, Seung-Ho; Kim, Hyo-Soo

    2009-01-01

    Background Previous randomized trials have showed the superiority of Paclitaxel-eluting stent over bare metal stent in angiographic and clinical outcomes. Coroflex Please™ stent is a newly developed drug eluting stent using the Coroflex™ stent platform combined with the drug paclitaxel contained in a polymer coating. PECOPS I trial, one-arm observational study, showed that the clinical and angiographic outcomes of Coroflex Please™ stent were within the range of those of Taxus, the 1st generation paclitaxel-eluting stent (PES). However, there have been no studies directly comparing the Coroflex Please™ stent with the Taxus Liberte™ stent that is the newest version of Taxus. Therefore, prospective, randomized trial is required to demonstrate the non-inferiority of Coroflex Please™ stent compared with Taxus Liberte™ stent in a head-to-head manner. Methods In the comparison of Efficacy between COroflex PLEASe™ ANd Taxus™ stent(ECO-PLEASANT) trial, approximately 900 patients are being prospectively and randomly assigned to the either type of Coroflex Please™ stent and Taxus Liberte™ stent via web-based randomization. The primary endpoint is clinically driven target vessel revascularization at 9 months. The secondary endpoints include major cardiac adverse events, target vessel failure, stent thrombosis and angiographic efficacy endpoints. Discussion The ECO-PLEASANT trial is the study not yet performed to directly compare the efficacy and safety of the Coroflex Please™ versus Taxus Liberte™ stent. On the basis of this trial, we will be able to find out whether the Coroflex Please™ stent is non-inferior to Taxus Liberte™ stent or not. Trial registration ClinicalTrials.gov number, NCT00699543. PMID:19849864

  11. Zotarolimus-eluting stent fracture at initial implantation diagnosed with StentBoost

    PubMed Central

    Arat Ozkan, Alev; Sinan, Umit Yasar; Gurmen, Aziz T

    2016-01-01

    Stent fracture is a rare complication of drug-eluting stent implantation with a reported rate of 0.84%–3.2% in various clinical studies with first-generation drug-eluting stents and 29% in autopsy studies. Sirolimus-eluting stents with their closed cell design were reported to be more prone to fracture compared to paclitaxel-eluting stents. Other risk factors for stent fracture are multiple stenting, longer stent length, chronic renal failure, right coronary artery intervention, and a higher maximal inflation pressure. The role of angiography in diagnosing stent fracture is limited, a fact also questioning the reliability of angiographic data. Image enhancement techniques like StentBoost are widely available in new-generation angiography systems and are used to assess stent expansion, overlap size, or to localize the postdilation balloon. Here, we report a case of zotarolimus-eluting stent fracture at initial implantation diagnosed with StentBoost. PMID:27489714

  12. Zotarolimus-eluting stent fracture at initial implantation diagnosed with StentBoost.

    PubMed

    Arat Ozkan, Alev; Sinan, Umit Yasar; Gurmen, Aziz T

    2016-01-01

    Stent fracture is a rare complication of drug-eluting stent implantation with a reported rate of 0.84%-3.2% in various clinical studies with first-generation drug-eluting stents and 29% in autopsy studies. Sirolimus-eluting stents with their closed cell design were reported to be more prone to fracture compared to paclitaxel-eluting stents. Other risk factors for stent fracture are multiple stenting, longer stent length, chronic renal failure, right coronary artery intervention, and a higher maximal inflation pressure. The role of angiography in diagnosing stent fracture is limited, a fact also questioning the reliability of angiographic data. Image enhancement techniques like StentBoost are widely available in new-generation angiography systems and are used to assess stent expansion, overlap size, or to localize the postdilation balloon. Here, we report a case of zotarolimus-eluting stent fracture at initial implantation diagnosed with StentBoost. PMID:27489714

  13. Molecular Mechanism of Local Drug Delivery with Paclitaxel-Eluting Membranes in Biliary and Pancreatic Cancer: New Application for an Old Drug

    PubMed Central

    Bang, Sookhee; Lee, Su Yeon; Baek, Yi-Yong; Yun, Jieun; Oh, Soo Jin; Lee, Chang Woo; Jo, Eun Ae; Yang, Sugeun; Lee, Don Haeng; Lee, Dong Ki

    2015-01-01

    Implantation of self-expanding metal stents (SEMS) is palliation for patients suffering from inoperable malignant obstructions associated with biliary and pancreatic cancers. Chemotherapeutic agent-eluting stents have been developed because SEMS are susceptible to occlusion by tumor in-growth. We reported recently that paclitaxel-eluting SEMS provide enhanced local drug delivery in an animal model. However, little is known about the molecular mechanisms by which paclitaxel-eluting stents attenuate tumor growth. We investigated the signal transduction pathways underlying the antiproliferative effects of a paclitaxel-eluting membrane (PEM) implanted in pancreatic/cholangiocarcinoma tumor bearing nude mice. Molecular and cellular alterations were analyzed in the PEM-implanted pancreatic/cholangiocarcinoma xenograft tumors by Western blot, immunoprecipitation, and immunofluorescence. The quantities of paclitaxel released into the tumor and plasma were determined by liquid chromatography-tandem mass spectroscopy. Paclitaxel from the PEM and its diffusion into the tumor inhibited angiogenesis, which involved suppression of mammalian target of rapamycin (mTOR) through regulation of hypoxia inducible factor (HIF-1) and increased apoptosis. Moreover, implantation of the PEM inhibited tumor-stromal interaction-related expression of proteins such as CD44, SPARC, matrix metalloproteinase-2, and vimentin. Local delivery of paclitaxel from a PEM inhibited growth of pancreatic/cholangiocarcinoma tumors in nude mice by suppressing angiogenesis via the mTOR and inducing apoptosis signal pathway. PMID:25983747

  14. Paclitaxel-eluting stents versus sirolimus-eluting stents in patients with diabetes mellitus undergoing percutaneous coronary intervention: a systematic review and meta-analysis of randomized controlled trials.

    PubMed

    Wang, Hui-Bo; Zeng, Ping; Yang, Jun; Yang, Jian; Liu, Xiao-Wen

    2016-10-01

    Uncertainties exist with regard to the efficacy of paclitaxel-eluting stents (PES) versus sirolimus-eluting stents (SES) in diabetes patients undergoing percutaneous coronary intervention (PCI). We performed a meta-analysis of randomized controlled trials (RCTs) to investigate the outcome of PES versus SES in diabetes patients undergoing PCI. A literature search was started, and we found all studies conducted from 2005 to 2016. We systematically searched the literature through the MEDLINE, Cochrane library, and EMBASE. Quality assessments were evaluated with the Jadad scale. Data were extracted considering the characteristics of efficacy and the safety of the designs. 12 RCTs satisfy the inclusion criteria. There is a significant decrease of target lesion revascularization (TLR) (MD = 0.65, 95 % CI = 0.42-1.00, P = 0.05) in a year and more than 1 year (MD = 0.54, 95 % CI = 0.37-0.78, P = 0.00010). A significant decrease of target vessel revascularization (TVR) in more than 1 year is (MD = 0.62, 95 % CI = 0.47-0.81, P = 0.0004). A significant decrease of major adverse cardiac events (MACE) in more than 1 year is (MD = 0.73, 95 % CI = 0.60-0.89, P = 0.002). Nevertheless, there is no significant difference in mortality (MD = 0.85, 95 % CI = 0.66-1.11, P = 0.24), stent thrombosis (ST) (MD = 0.65, 95 % CI = 0.35-1.21, P = 0.18), or myocardial infarction (MD = 1.04, 95 % CI = 0.71-1.51, P = 0.84). SES may be more significant in decreasing TLR, TVR, and MACE than PES without significantly increasing mortality, ST and MI in diabetes patients.

  15. Paclitaxel-eluting stents versus sirolimus-eluting stents in patients with diabetes mellitus undergoing percutaneous coronary intervention: a systematic review and meta-analysis of randomized controlled trials.

    PubMed

    Wang, Hui-Bo; Zeng, Ping; Yang, Jun; Yang, Jian; Liu, Xiao-Wen

    2016-10-01

    Uncertainties exist with regard to the efficacy of paclitaxel-eluting stents (PES) versus sirolimus-eluting stents (SES) in diabetes patients undergoing percutaneous coronary intervention (PCI). We performed a meta-analysis of randomized controlled trials (RCTs) to investigate the outcome of PES versus SES in diabetes patients undergoing PCI. A literature search was started, and we found all studies conducted from 2005 to 2016. We systematically searched the literature through the MEDLINE, Cochrane library, and EMBASE. Quality assessments were evaluated with the Jadad scale. Data were extracted considering the characteristics of efficacy and the safety of the designs. 12 RCTs satisfy the inclusion criteria. There is a significant decrease of target lesion revascularization (TLR) (MD = 0.65, 95 % CI = 0.42-1.00, P = 0.05) in a year and more than 1 year (MD = 0.54, 95 % CI = 0.37-0.78, P = 0.00010). A significant decrease of target vessel revascularization (TVR) in more than 1 year is (MD = 0.62, 95 % CI = 0.47-0.81, P = 0.0004). A significant decrease of major adverse cardiac events (MACE) in more than 1 year is (MD = 0.73, 95 % CI = 0.60-0.89, P = 0.002). Nevertheless, there is no significant difference in mortality (MD = 0.85, 95 % CI = 0.66-1.11, P = 0.24), stent thrombosis (ST) (MD = 0.65, 95 % CI = 0.35-1.21, P = 0.18), or myocardial infarction (MD = 1.04, 95 % CI = 0.71-1.51, P = 0.84). SES may be more significant in decreasing TLR, TVR, and MACE than PES without significantly increasing mortality, ST and MI in diabetes patients. PMID:27631549

  16. Randomized trial of Legflow® paclitaxel eluting balloon and stenting versus standard percutaneous transluminal angioplasty and stenting for the treatment of intermediate and long lesions of the superficial femoral artery (RAPID trial): study protocol for a randomized controlled trial

    PubMed Central

    2013-01-01

    Background Restenosis after percutaneous transluminal angioplasty (PTA) of the superficial femoral artery (SFA) may occur in 45% of patients at 2 years follow-up. Paclitaxel-coated balloons have been found to reduce neointimal hyperplasia, and thus reduce restenosis. Recently, the Legflow® paclitaxel-coated balloon (Cardionovum Sp.z.o.o., Warsaw, Poland) (LPEB) has been introduced. This balloon is covered with shellac, a Food and Drug Administration (FDA) approved natural resin, to obtain an equally distributed tissue concentration of paclitaxel. The RAPID trial is designed to assess restenosis after PTA using the Legflow balloon combined with nitinol stenting versus uncoated balloons with nitinol stenting in SFA lesions >5 cm. Methods/Design A total of 176 adult patients with Rutherford class 2 to class 6 symptoms due to intermediate (5–15 cm) or long (>15 cm) atherosclerotic lesions in the SFA will be randomly allocated for treatment with LPEB with nitinol stenting or uncoated balloon angioplasty with stenting. Stenting will be performed using the Supera® stent in both groups (IDEV Technologies Inc., Webster, TX). The primary endpoint is the absence of binary restenosis of the treated SFA segment. Secondary outcomes are target lesion revascularization (TLR), clinical and hemodynamic outcome, amputation rate, mortality rate, adverse events, and device-specific adverse events. Follow up consists of four visits in which ankle-brachial indices (ABI), toe pressure measurements, and duplex ultrasound (DUS) will be performed. Furthermore, a peripheral artery questionnaire (PAQ) will be completed by the patients at each follow-up. In the event that DUS reveals a symptomatic >50% restenosis, or a >75% asymptomatic restenosis, additional digital subtraction angiography will be performed with any necessary re-intervention. Discussion The RAPID trial is a multicenter randomized controlled patient blind trial that will provide evidence concerning whether the use of the

  17. Paclitaxel-eluting balloon dilation of biliary anastomotic stricture after liver transplantation

    PubMed Central

    Hüsing, Anna; Reinecke, Holger; Cicinnati, Vito R; Beckebaum, Susanne; Wilms, Christian; Schmidt, Hartmut H; Kabar, Iyad

    2015-01-01

    AIM: To investigate the safety and effectiveness of endoscopic therapy with a paclitaxel-eluting balloon (PEB) for biliary anastomotic stricture (AS) after liver transplantation (LT). METHODS: This prospective pilot study enrolled 13 consecutive eligible patients treated for symptomatic AS after LT at the University Hospital of Münster between January 2011 and March 2014. The patients were treated by endoscopic therapy with a PEB and followed up every 8 wk by endoscopic retrograde cholangiopancreatography (ERCP). In cases of re-stenosis, further balloon dilation with a PEB was performed. Follow-up was continued until 24 mo after the last intervention. RESULTS: Initial technical feasibility, defined as successful balloon dilation with a PEB during the initial ERCP procedure, was achieved in 100% of cases. Long-term clinical success (LTCS), defined as no need for further endoscopic intervention for at least 24 mo, was achieved in 12 of the 13 patients (92.3%). The mean number of endoscopic interventions required to achieve LTCS was only 1.7 ± 1.1. Treatment failure, defined as the need for definitive alternative treatment, occurred in only one patient, who developed recurrent stenosis with increasing bile duct dilatation that required stent placement. CONCLUSION: Endoscopic therapy with a PEB is very effective for the treatment of AS after LT, and seems to significantly shorten the overall duration of endoscopic treatment by reducing the number of interventions needed to achieve LTCS. PMID:25624733

  18. Simultaneous occlusion of left anterior descending and left circumflex arteries by very late stent thrombosis: vascular response to drug-eluting stents assessed by intravascular ultrasound.

    PubMed

    Yamawaki, Masahiro; Onuma, Yoshinobu; Nakano, Masatsugu; Muramatsu, Takashi; Nakatani, Shimpei; Ishibashi, Yuki; Ishimori, Hiroshi; Hirano, Keisuke; Ito, Yoshiaki; Tsukahara, Reiko; Muramatsu, Toshiya

    2015-11-01

    Very late stent thrombosis (VLST) is a catastrophic complication after implantation of a drug-eluting stent (DES). It has been reported that VLST is associated with pathological changes, which often include late acquired incomplete stent apposition (LAISA) with thrombus formation. In addition, the vascular response to the stent (evaginations, neointimal growth, and thrombosis) and the incidence of LAISA are reported to vary among the different types of DES. We experienced a patient with cardiogenic shock induced by simultaneous VLST of both the left anterior descending artery (LAD) and the left circumflex artery (LCX) at 3 years after implantation of two sirolimus-eluting stents. Intravascular ultrasound (IVUS) showed LAISA of both arteries. A paclitaxel-eluting stent, which had been implanted in the right coronary artery 3 years earlier, did not show such a finding. IVUS revealed "different vascular reactions" to "different types of DES" in this patient.

  19. Therapies targeting inflammation after stent implantation.

    PubMed

    Okura, Hiroyuki; Takagi, Tsutomu; Yoshida, Kiyoshi

    2013-07-01

    Since the introduction of coronary vessel scaffold by metallic stent, percutaneous coronary intervention has become widely performed all over the world. Although drug-eluting stent technology has further decrease the incidence of in-stent restenosis, there still remaining issues related to stent implantation. Vessel inflammation is one of the causes that may be related to stent restenosis as well as stent thrombosis. Therefore, systemic therapies targeting inflammation emerged as adjunctive pharmacological intervention to improve outcome. Statins, corticosteroids, antiplatelets, and immunosuppresive or anti-cancer drugs are reported to favorably impact outcome after bare-metal stent implantation. In type 2 diabetic patients, pioglitazone may be the most promising drug that can lower neointimal proliferation and, as a result, lower incidence of restenosis and target lesion revascularization. On the other hand, several new stent platforms that might decrease inflammatory response after drug-eluting stent implantation have been introduced. Because durable polymer used in the first generation drug-eluting stents are recognized to be responsible for unfavorable vessel response, biocompatible or bioabsorbable polymer has been introduce and already used clinically. Furthermore, polymer-free drug-eluting stent and bioresorbable scaffold are under investigation. Although vessel inflammation may be reduced by using these new drug-eluting stents or scaffold, long-term impact needs to be investigated further. PMID:23905635

  20. Meta-analysis of randomized trials comparing the effectiveness of different strategies for the treatment of drug-eluting stent restenosis.

    PubMed

    Piccolo, Raffaele; Galasso, Gennaro; Piscione, Federico; Esposito, Giovanni; Trimarco, Bruno; Dangas, George D; Mehran, Roxana

    2014-11-01

    The investigators performed a network meta-analysis of randomized trials comparing the effectiveness of currently available strategies for the treatment of drug-eluting stent (DES) restenosis. Despite the widespread use of DES in patients who undergo percutaneous coronary intervention, the optimal treatment for DES restenosis remains poorly defined. A systematic search of electronic resources was performed. The primary end point was diameter stenosis at follow-up angiography. Seven trials were included, enrolling a total of 1,586 patients with 1,728 restenotic lesions. The following treatment options were found: balloon angioplasty (BA) in 343 patients (19.3%), iopromide-based paclitaxel-eluting balloons (PEB) in 343 (21.6%), sirolimus-eluting stents in 441 (27.8%), paclitaxel-eluting stents in 462 (29.1%), and everolimus-eluting stents in 34 (2.2%). Compared with BA, PEB (-17.74%, 95% credible interval [CI] -25.17% to -11.31%), everolimus-eluting stents (-14.93%, 95% CI -33.47% to 1.16%), paclitaxel-eluting stents (-15.3%, 95% CI -22.96% to -8.35%), and sirolimus-eluting stents (-11.08%, 95% CI -17.89% to -3.4%) had similar reductions in diameter stenosis at follow-up angiography. PEB (85%) and everolimus-eluting stents (68%) had the greatest probabilities for being the best treatment option. Furthermore, PEB were the best treatment in terms of late luminal loss (85%) and binary restenosis (85%). BA had the lowest efficacy with respect to all study end points. In conclusion, in patients with DES restenosis, repeat DES implantation and iopromide-based PEB are valid alternatives. However, PEB had greater angiographic efficacy and therefore should be considered the new benchmark comparator in the treatment of DES restenosis. The use of BA should be discouraged in patients with DES restenosis.

  1. Meta-analysis of randomized trials comparing the effectiveness of different strategies for the treatment of drug-eluting stent restenosis.

    PubMed

    Piccolo, Raffaele; Galasso, Gennaro; Piscione, Federico; Esposito, Giovanni; Trimarco, Bruno; Dangas, George D; Mehran, Roxana

    2014-11-01

    The investigators performed a network meta-analysis of randomized trials comparing the effectiveness of currently available strategies for the treatment of drug-eluting stent (DES) restenosis. Despite the widespread use of DES in patients who undergo percutaneous coronary intervention, the optimal treatment for DES restenosis remains poorly defined. A systematic search of electronic resources was performed. The primary end point was diameter stenosis at follow-up angiography. Seven trials were included, enrolling a total of 1,586 patients with 1,728 restenotic lesions. The following treatment options were found: balloon angioplasty (BA) in 343 patients (19.3%), iopromide-based paclitaxel-eluting balloons (PEB) in 343 (21.6%), sirolimus-eluting stents in 441 (27.8%), paclitaxel-eluting stents in 462 (29.1%), and everolimus-eluting stents in 34 (2.2%). Compared with BA, PEB (-17.74%, 95% credible interval [CI] -25.17% to -11.31%), everolimus-eluting stents (-14.93%, 95% CI -33.47% to 1.16%), paclitaxel-eluting stents (-15.3%, 95% CI -22.96% to -8.35%), and sirolimus-eluting stents (-11.08%, 95% CI -17.89% to -3.4%) had similar reductions in diameter stenosis at follow-up angiography. PEB (85%) and everolimus-eluting stents (68%) had the greatest probabilities for being the best treatment option. Furthermore, PEB were the best treatment in terms of late luminal loss (85%) and binary restenosis (85%). BA had the lowest efficacy with respect to all study end points. In conclusion, in patients with DES restenosis, repeat DES implantation and iopromide-based PEB are valid alternatives. However, PEB had greater angiographic efficacy and therefore should be considered the new benchmark comparator in the treatment of DES restenosis. The use of BA should be discouraged in patients with DES restenosis. PMID:25242363

  2. Foreign body contamination during stent implantation.

    PubMed

    Whelan, D M; van Beusekom, H M; van der Giessen, W J

    1997-03-01

    The treatment of coronary artery disease using stents has become a widely accepted technique. However, the inadvertent co-implantation of contaminating factors with the stent has received little attention. We studied histological cross-sections of stented porcine coronary arteries and observed contamination of some vessels with surgical glove powder and textile fibres. The contaminating particles were associated with a foreign body reaction. Such a reaction could delay the wound-healing response of a stented vessel and thereby prolong the period in which subacute thrombosis could occur. It is also proposed that air contamination could affect the thrombogenicity of the stent. Appropriate measures should be followed to reduce the chance of contamination occurring.

  3. Use of paclitaxel-eluting balloons for endotherapy of anastomotic strictures following liver transplantation.

    PubMed

    Kabar, I; Cicinnati, V R; Beckebaum, S; Cordesmeyer, S; Avsar, Y; Reinecke, H; Schmidt, H H

    2012-12-01

    Biliary anastomotic strictures after liver transplantation are a major source of morbidity and graft failure; however, repeated endoscopic therapy has shown variable long-term success rates. Thus the aim of this prospective case series was to evaluate the safety and efficacy of using paclitaxel-eluting balloons in 13 patients requiring treatment for symptomatic anastomotic strictures following liver transplantation. Sustained clinical success-defined as no need for further endoscopic intervention for at least 6 months - was achieved in 12 /13 patients (92 %). One, two, and three interventions were required in 9 (69 %), 1, and 2 patients, respectively (mean number of sessions was 1.46). Mean (± SD) bilirubin level dropped from 6.8 (± 4.1) mg/dL to 1.4 (± 0.9) mg/dL. These promising results justify carrying out a randomized comparative trial to confirm this innovative approach. PMID:23188664

  4. Pulmonary Arterial Stent Implantation in an Adult with Williams Syndrome

    SciTech Connect

    Reesink, Herre J.; Henneman, Onno D. F.; Delden, Otto M. van; Biervliet, Jules D.; Kloek, Jaap J.; Reekers, Jim A.; Bresser, Paul

    2007-07-15

    We report a 38-year-old patient who presented with pulmonary hypertension and right ventricular dysfunction due to pulmonary artery stenoses as a manifestation of Williams syndrome, mimicking chronic thromboembolic pulmonary hypertension. The patient was treated with balloon angioplasty and stent implantation. Short-term follow-up showed a good clinical result with excellent patency of the stents but early restenosis of the segments in which only balloon angioplasty was performed. These stenoses were subsequently also treated successfully by stent implantation. Stent patency was observed 3 years after the first procedure.

  5. New approach to quantitative angiographic assessment after stent implantation.

    PubMed

    Reimers, B; Di Mario, C; Di Francesco, L; Moussa, I; Blengino, S; Martini, G; Reiber, J H; Colombo, A

    1997-04-01

    The new generation quantitative angiographic systems apply the interpolated technique to calculate the reference diameter at the site of the stenosis by integrating measurements of the segments proximal and distal to the stenosis. After stent implantation these measurements can be misleading as the treated segment, which is frequently larger than the adjacent not stented segments, is included in the measurements. The consequence is an overestimation of the reference diameter and the residual diameter stenosis. The present study was performed to compare this conventional technique of measurement with a new method which excludes the stented segment for the calculation of the reference diameter. Fifty-two lesions treated with poorly radiopaque stents (56% Palmaz-Schatz, 28% NIR, 10% Gianturco-Roubin, 6% Wallstent) expanded at high pressure (> = or 16 atm) were analyzed according to the conventional and stent excluded method. After stent implantation the reference diameter was 3.39 +/- 0.48 mm with conventional measurements and 3.02 +/- 0.45 mm with the stent excluded method (P < 0.05). The corresponding % diameter stenosis was 13 +/- 9 for the conventional technique and 1 +/- 13 for the stent excluded analysis (P < 0.05). The new approach to quantitative coronary analysis after stenting provides higher accuracy in reference diameter calculations and allows a more appropriate matching of stented segments with adjacent normal segments.

  6. Neoatherosclerosis after Drug-Eluting Stent Implantation: Roles and Mechanisms

    PubMed Central

    Cui, Yuanyuan; Shi, Dazhuo; Chen, Keji

    2016-01-01

    In-stent neoatherosclerosis (NA), characterized by a relatively thin fibrous cap and large volume of yellow-lipid accumulation after drug-eluting stents (DES) implantation, has attracted much attention owing to its close relationship with late complications, such as revascularization and late stent thrombosis (ST). Accumulating evidence has demonstrated that more than one-third of patients with first-generation DES present with NA. Even in the advent of second-generation DES, NA still occurs. It is indicated that endothelial dysfunction induced by DES plays a critical role in neoatherosclerotic development. Upregulation of reactive oxygen species (ROS) induced by DES implantation significantly affects endothelial cells healing and functioning, therefore rendering NA formation. In light of the role of ROS in suppression of endothelial healing, combining antioxidant therapies with stenting technology may facilitate reestablishing a functioning endothelium to improve clinical outcome for patients with stenting. PMID:27446509

  7. Neoatherosclerosis after Drug-Eluting Stent Implantation: Roles and Mechanisms

    PubMed Central

    Cui, Yuanyuan; Shi, Dazhuo; Chen, Keji

    2016-01-01

    In-stent neoatherosclerosis (NA), characterized by a relatively thin fibrous cap and large volume of yellow-lipid accumulation after drug-eluting stents (DES) implantation, has attracted much attention owing to its close relationship with late complications, such as revascularization and late stent thrombosis (ST). Accumulating evidence has demonstrated that more than one-third of patients with first-generation DES present with NA. Even in the advent of second-generation DES, NA still occurs. It is indicated that endothelial dysfunction induced by DES plays a critical role in neoatherosclerotic development. Upregulation of reactive oxygen species (ROS) induced by DES implantation significantly affects endothelial cells healing and functioning, therefore rendering NA formation. In light of the role of ROS in suppression of endothelial healing, combining antioxidant therapies with stenting technology may facilitate reestablishing a functioning endothelium to improve clinical outcome for patients with stenting.

  8. The incidence of stent-edge spasm after stent implantation in patients with or without vasospastic angina pectoris.

    PubMed

    Kaku, Bunji; Honin, I Kanaya; Horita, Yhuki; Uno, Yoshihide; Yamazaki, Tsukasa; Funada, Akira; Ohka, Takio

    2005-01-01

    Although several investigations have reported that stent implantation is an option for the treatment of vasospastic angina (VSA) that is resistant to medical treatment, we are concerned about the occurrence of new stent-edge spasms after stenting. The purpose of this study was to determine the incidence of new stent-edge spasms after stenting. Twenty-seven patients with VSA and 23 patients without VSA were enrolled. About 6 months after stent implantaion, a spasm provocation test was performed by intracoronary infusion of acetylcholine or ergonovine in 26 patients with VSA and all patients without VSA, and the induced stent-edge spasms were classified as either moderate (stent-edge spasm > 75% and < 95% reduction in coronary artery diameter) or severe (stent-edge spasm > 95% reduction in coronary artery diameter). In one patient with VSA, stent-edge spasm and acute thrombosis occurred several hours after stent implantation. The remaining 26 patients with VSA had no complications during or after stent implantation. However, during the chronic phase, severe stent-edge spasm was provoked in 5 patients with VSA (19.2%) and in 2 patients without VSA (8.7%). Moderate stent-edge spasm was provoked in 5 patients with VSA (19.2%) and 5 patients without VSA (21.7%). The results suggest new onset stent-edge spasm in patients either with or without VSA should not be neglected.

  9. Stent implantation influence wall shear stress evolution

    NASA Astrophysics Data System (ADS)

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

    2016-06-01

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

  10. Intravascular brachytherapy with radioactive stents produced by ion implantation

    NASA Astrophysics Data System (ADS)

    Golombeck, M.-A.; Heise, S.; Schloesser, K.; Schuessler, B.; Schweickert, H.

    2003-05-01

    About 1 million patients are treated for stenosis of coronary arteries by percutaneous balloon angioplasty annually worldwide. In many cases a so called stent is inserted into the vessel to keep it mechanically open. Restenosis is observed in about 20-30% of these cases, which can be treated by irradiating the stented vessel segment. In our approach, we utilized the stent itself as radiation source by ion implanting 32P. Investigations of the surface properties were performed with special emphasis on activity retention. Clinical data of about 400 patients showed radioactive stents can suppress instent restenosis, but a so called edge effect appeared, which can be avoided by the new "drug eluting stents".

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

    PubMed

    Zang, Chuanshan; Sun, Jian; Sun, Yan

    2016-03-01

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

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

    PubMed

    Zang, Chuanshan; Sun, Jian; Sun, Yan

    2016-03-01

    We report the treatment of one patient with pharynx anastomotic stenosis after cervical esophagealresection by stent implantation. The patient suffered from serious pharynx anastomotic stenosis after gastric-pha-ryngeal anastomosis. After balloon-dilatation,a domestic self-expanding Z-stents was implanted in the stricture ofthe esophagus under the X-rays. After stent implantation, the patient has been leading a normal life for threeyears. Balloon dilatation and stent implantation is an effective and safe method in the treatment of patients withpharynx anastomotic stenosis. PMID:27382696

  13. Inflammation and impaired wound healing after zotarolimus-eluting stent implantation.

    PubMed

    Yoneda, Shuichi; Abe, Shichiro; Taguchi, Isao; Masawa, Nobuhide; Inoue, Katsumi; Inoue, Teruo

    2012-01-01

    An 86-year-old man died suddenly 5 months after implantation of a zotarolimus-eluting stent. Two zotarolimus-eluting stents were placed to treat a highly calcified diffuse lesion in the proximal-to-mid right coronary artery. The lesion was fully covered by the two stents, and intravascular ultrasound showed complete stent apposition. However, an X-ray at autopsy showed that the proximal stent was fractured. Although we thought that thrombotic occlusion at the fracture site might have caused his sudden death, no thrombus was present. In addition, in the other sites where the stents were optimally dilated, there was stent malapposition and peri-strut inflammation including macrophage infiltration, giant cells, polymer phagocytosis, and neovascularization in the neointima. Even with a second-generation drug-eluting stent, such as the zotarolimus-eluting stent, wound healing may be impaired at the stent-injured vessel site.

  14. Black hole restenosis after drug-eluting stent implantation for in-stent restenosis: potential mechanism and optimal strategy.

    PubMed

    Otsuka, Yoritaka; Murata, Takashi; Kono, Michiaki; Imoto, Hiroki; Koyama, Taku; Nakamura, Keita; Kadama, Sunao; Noguchi, Hiroo; Saito, Taro

    2015-09-01

    In-stent restenosis (ISR) has long remained as the major limitation of coronary stenting. The use of drug-eluting stent (DES) reduces the risk of repeat revascularization without an increase of death and myocardial infarction, compared to the standard bare metal stents. DES has also demonstrated markedly to reduce ISR for complex lesions. However, ISR after DES implantation still occurs and optimal treatment for ISR after DES has not been established. Herein, we report 3 cases with black hole restenosis confirmed by intravascular ultrasound at the site of overlapped DES and discuss potential mechanism and optimal strategy for this phenomenon.

  15. Optimization of Drug Delivery by Drug-Eluting Stents

    PubMed Central

    Bozsak, Franz; Gonzalez-Rodriguez, David; Sternberger, Zachary; Belitz, Paul; Bewley, Thomas; Chomaz, Jean-Marc; Barakat, Abdul I.

    2015-01-01

    Drug-eluting stents (DES), which release anti-proliferative drugs into the arterial wall in a controlled manner, have drastically reduced the rate of in-stent restenosis and revolutionized the treatment of atherosclerosis. However, late stent thrombosis remains a safety concern in DES, mainly due to delayed healing of the endothelial wound inflicted during DES implantation. We present a framework to optimize DES design such that restenosis is inhibited without affecting the endothelial healing process. To this end, we have developed a computational model of fluid flow and drug transport in stented arteries and have used this model to establish a metric for quantifying DES performance. The model takes into account the multi-layered structure of the arterial wall and incorporates a reversible binding model to describe drug interaction with the cells of the arterial wall. The model is coupled to a novel optimization algorithm that allows identification of optimal DES designs. We show that optimizing the period of drug release from DES and the initial drug concentration within the coating has a drastic effect on DES performance. Paclitaxel-eluting stents perform optimally by releasing their drug either very rapidly (within a few hours) or very slowly (over periods of several months up to one year) at concentrations considerably lower than current DES. In contrast, sirolimus-eluting stents perform optimally only when drug release is slow. The results offer explanations for recent trends in the development of DES and demonstrate the potential for large improvements in DES design relative to the current state of commercial devices. PMID:26083626

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

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

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

  17. Optical coherence tomography in bioabsorbable stents: mechanism of vascular response and guidance of stent implantation.

    PubMed

    Mattesini, A; Pighi, M; Konstantinidis, N; Ghione, M; Kilic, D; Foin, N; Dall'ara, G; Secco, G G; Valente, S; Di Mario, C

    2014-02-01

    Fully biodegradable L-polylactic acid stents (biodegradable vascular scaffold, BVS), the latest breakthrough in the area of coronary implants, entered clinical trials in 2005 and became commercially available in 2011. Optical coherence tomography (OCT) was used from the first implants to study the vessel wall response and the timing of the resorption process in man. Analysis of BVS with OCT has several advantages over that of metallic stents. BVS polymeric struts are transparent to the light so that scaffold integrity, apposition to the underlying wall, presence of thrombus and hyperplasia, and changes in the strut characteristics over time can be easily studied. We present a comprehensive review of the findings OCT provided when used as a research tool in serial examination up to five years for investigation of the mechanism of resorption, neointimal coverage, shrinkage and late lumen enlargement. We also report our experience with OCT in 47 lesions of various complexity as a practical means of percutaneous coronary intervention guidance during BVS implantation. PMID:24500218

  18. Preliminary report on a new concept stent prototype designed for venous implant.

    PubMed

    Lugli, M; Maleti, O

    2015-08-01

    Venous obstruction at iliocaval level in both forms, primary and secondary, is a significant cause of severe chronic venous insufficiency. A new therapeutic approach to this pathology emerged with the introduction of stenting procedures that proved effective, leading to good long-term results. However, at present, the majority of implanted stents have been designed for arterial implant and this can pose a limit in particular districts. The purpose of this preliminary acute study was to verify the deliverability and safety of a new stent specially designed for venous-vessel implant. We assess the safety and deliverability of two braided, self-expanding, nickel-titanium stents (Jotec GmbH, Hechingen, Germany) specially designed for endovascular implant in veins. The two stents, despite being based on the same concept, have a different design: stent A presents a proximal tapering shape specially designed to reduce migration, while stent B does not. Both of them are enlarged at their distal extremity and present variable radial force the length of the stent itself, the said force becoming very high in the intermediate segment. Stents were implanted in the internal jugular vein of a sheep, showing optimal deliverability. The completion venography showed the migration of stent B into the right atrium. Stent A maintained its location, confirmed by intravascular ultrasound examination. No scaffolding effect was detected and an adequate adherence and adaptability to the vein wall was obtained. In conclusions, the stent A design matches the characteristics required by vein implants. Stability is achieved even where difficult anatomical conditions apply, such as in the jugular vein. Deployment is easy and precise in a given landing zone. Radial resistive force is very high, as required in specific vein districts, but is also associated with good flexibility. Following this preliminary acute report, further studies are required. PMID:24920424

  19. Inadvertent intracoronary stent extraction 10 months after implantation complicating cutting balloon angioplasty for in-stent restenosis

    SciTech Connect

    Almeda, Francis Q.; Billhardt, Roger A

    2003-09-01

    We report the case of an unusual complication for Cutting Balloon Angioplasty (CBA) during treatment for instent restenosis (ISR), which resulted in inadvertent intracoronary stent extraction 10 months after implantation. In this case report, CBA was utilized to treat an ISR lesion in the distal right coronary artery (RCA). Due to difficulty in withdrawing the cutting balloon into the guide after treatment of the lesion, the entire system (guide, cutting balloon, and guidewire) was removed as a unit from the body. Upon examination of the system, the previously placed stent in the distal RCA was attached to the microtomes of the cutting balloon. Although the precise mechanisms for stent extraction in this case remain speculative, the initial stent used in the distal RCA may have been undersized, and this may have played a major role in this complication. Although there is limited data regarding the optimal strategy to treat the site of the inadvertent stent extraction, we opted to re-stent the area with a properly-sized coronary stent. Following the intervention, there was no residual stenosis with TIMI 3 flow through the vessel. The patient remained asymptomatic and a serum troponin drawn 18 hours after the procedure was normal, and he was discharged the next day. The interventionist must be vigilant about this rare but serious complication when applying CBA in the treatment of ISR, particularly when an undersized or underdeployed stent is suspected.

  20. [Stent implantation as initial coronary interventional therapy? A theoretical model on clinical and economical consequences of in-stent restenosis].

    PubMed

    Pfund, A; Wendland, G; Baer, F; Lauterbach, K; Höpp, H W

    2000-08-01

    The reduction of acute complications and late restenosis compared to conventional PTCA has led to a rapid increase in stent implantation as initial treatment for coronary stenosis. As a result, in-stent restenosis has become an important clinical and economical problem, especially the diffuse form, which is much more likely to reappear. In order to compare the consequences of initial stenting and initial angioplasty, we developed an analytic model, considering the differences between diffuse and focal in-stent restenosis. The simulation based on the optimized therapeutic proceeding following an elective 1-vessel revascularization of a 60-year-old patient, dealing with probabilities for acute complications and late restenosis taken from the literature and in-hospital costs obtained from 200 elective interventions. In the stent group 71.0% of patients were free of any target lesion-related event, compared to 60.2% in the PTCA group. Catheter reintervention was necessary for 32.1% of the patients initially treated with angioplasty and for 17.6% of the initially stented patients, whereas 7.7% of the stent patients had to undergo elective bypass surgery as final treatment compared to 2.8% in the PTCA arm. Long-term medical costs for initial stenting (6,237 Euros) were 14% higher than for conventional PTCA (5,345 Euros). Taking also into consideration the indirect costs (loss of productivity) for a collective with an employment rate of 50%, the difference between stent implantation (9,067 Euros) and angioplasty (8,581 Euros) is smaller. Initial treatment of coronary stenosis by stent implantation decreases the rate of repeat revascularization compared to initial PTCA, but there is a greater likelihood that elective bypass surgery will become necessary. This difference in following treatment is related to the occurrence of diffuse in-stent restenosis. When calculating the long-term costs stenting still appeared to be more expensive than PTCAA because the savings in

  1. Influence of Vessel Size and Tortuosity on In-stent Restenosis After Stent Implantation in the Vertebral Artery Ostium

    SciTech Connect

    Zhou Zhiming; Yin Qin; Xu Gelin; Yue Xuanye; Zhang Renliang; Zhu Wusheng; Fan Xiaobing; Ma Minmin; Liu Xinfeng

    2011-06-15

    Purpose: Percutaneous transluminal angioplasty and stenting is emerging as an alternative for treating atherosclerotic stenosis in the vertebral artery ostium. However, in-stent restenosis (ISR) still remains a critical issue to be addressed. Little is known about the relationship between anatomic characteristics of the artery and ISR after stent implantation. In this study, we have evaluated influential factors for ISR in a cohort of the patients with stenting in the vertebral artery ostium. Methods: Sixty-one patients with 63 symptomatic lesions in vertebral artery ostium treated with stenting were enrolled onto this study. An average of 12.5 months' clinical and angiographic follow-up results were analyzed retrospectively. The possible influential factors for ISR, including conventional risk factors of cerebrovascular diseases and morphological characteristics of target lesions, were evaluated by univariate and multivariate regression analysis. Results: Technical success was achieved in all 63 interventional procedures. Stenosis was reduced from (mean {+-} standard deviation) 75.5 {+-} 12% before to 1 {+-} 3.6% after the procedure. During the mean 12.5-month angiographic follow-up, ISR was detected in 17 treated vessels (27.0%), with 2 treated arteries (3.2%) resulting in occlusion, and a stent fracture in 1 case (1.6%). Multivariate Cox regression analysis showed that the tortuosity of V1 (hazard ratio 3.54, P = 0.01) and smaller diameter of the stent (hazard ratio 3.8, P = 0.04) were independent predictors of ISR. Conclusions: Angioplasty and stenting for symptomatic stenosis in the vertebral artery ostium stenosis seem to be feasible and effective. Tortuosity and smaller diameter may affect ISR after stent implantation.

  2. Atherosclerotic plaque behind the stent changes after bare-metal and drug-eluting stent implantation in humans: implications for late stent failure?

    PubMed Central

    Andreou, Ioannis; Takahashi, Saeko; Tsuda, Masaya; Shishido, Koki; Antoniadis, Antonios P.; Papafaklis, Michail I.; Mizuno, Shingo; Coskun, Ahmet U.; Saito, Shigeru; Feldman, Charles L.; Edelman, Elazer R.; Stone, Peter H.

    2016-01-01

    Background and aims The natural history and the role of atherosclerotic plaque located behind the stent (PBS) are still poorly understood. We evaluated the serial changes in PBS following bare-metal (BMS) compared to first-generation drug-eluting stent (DES) implantation and the impact of these changes on in-stent neointimal hyperplasia (NIH). Methods Three-dimensional coronary reconstruction by angiography and intravascular ultrasound was performed after intervention and at 6–10-month follow-up in 157 patients with 188 lesions treated with BMS (n=89) and DES (n=99). Results There was a significant decrease in PBS area (−7.2%; p<0.001) and vessel area (−1.7%; p<0.001) after BMS and a respective increase in both areas after DES implantation (6.1%; p<0.001 and 4.1%; p<0.001, respectively). The decrease in PBS area significantly predicted neointimal area at follow-up after BMS (β: 0.15; 95% confidence interval [CI]: 0.10–0.20, p<0.001) and DES (β: 0.09; 95% CI: 0.07–0.11; p<0.001) implantation. The decrease in PBS area was the most powerful predictor of significant NIH after BMS implantation (odds ratio: 1.13; 95% CI: 1.02–1.26; p=0.02). Conclusions The decrease in PBS area after stent implantation is significantly associated with the magnitude of NIH development at follow-up. This finding raises the possibility of a communication between the lesion within the stent and the underlying native atherosclerotic plaque, and may have important implications regarding the pathobiology of in-stent restenosis and late/very late stent thrombosis. PMID:27494445

  3. Image-based dosimetry of an implanted radioactive stent using intravascular ultrasound

    NASA Astrophysics Data System (ADS)

    Peterson, Stephen W.

    Angioplasty has become an increasingly popular and effective treatment for heart disease. Unfortunately, restenosis, a cellular and biological reaction to the procedure, has hindered its effectiveness. Two of the most successful methods of inhibiting restenosis are radiation and stents. The combination of these two components, radioactive stents, is not as common as some of the other methods, yet still has potential of slowing restenosis. Investigation into source characteristics and artery wall radiobiology may illuminate some possible solutions to the problems of restenosis. This work has developed a calculational method to look at in-vivo images of implanted stents and determine the dose to the artery walls in order to test different source characteristics. The images are Intravascular Ultrasound (IVUS) cross-sectional slices of the stent and the artery. From these images, it is possible to determine the implanted stent structure. The pieces of the stent are identified in the images and modeled in a Monte Carlo simulation, using MCNP4c3. The simulation results were combined with the images to give three-dimensional absolute dose contours of the stent. The absolute dose values were verified using radiochromic film and 198Au-plated stents. This work was able to successfully verify the dose results and create a three-dimensional dose map of the implanted stent.

  4. Effectiveness of sirolimus-eluting stent implantation for the treatment of coronary artery disease in octogenarians.

    PubMed

    Vijayakumar, Maniyal; Lemos, Pedro A; Hoye, Angela; Ong, Andrew T L; Aoki, Jiro; Granillo, Gaston Rodriguez; McFadden, Eugene P; Sianos, Georgios; Hofma, Sjoerd H; Smits, Pieter C; van der Giessen, Willem J; de Feyter, Pim; van Domburg, Ron T; Cummins, Paul A; Serruys, Patrick W

    2004-10-01

    Sirolimus-eluting stent (SES) implantation has been shown to reduce repeat revascularization in various randomized trials. The present study evaluated the outcomes after SES implantation in 46 octogenarian patients. SES implantation in octogenarians appears to be feasible and is associated with very small subsequent need for repeat target vessel revascularization at 1 year.

  5. Experimental Comparison of the Hemodynamic Effects of Bifurcating Coronary Stent Implantation Techniques

    NASA Astrophysics Data System (ADS)

    Brindise, Melissa; Vlachos, Pavlos; AETheR Lab Team

    2015-11-01

    Stent implantation in coronary bifurcations imposes unique effects to the blood flow patterns and currently there is no universally accepted stent deployment approach. Despite the fact that stent-induced changes can greatly alter clinical outcomes, no concrete understanding exists regarding the hemodynamic effects of each implantation method. This work presents an experimental evaluation of the hemodynamic differences between implantation techniques. We used four common stent implantation methods including the currently preferred one-stent provisional side branch (PSB) technique and the crush (CRU), Culotte (CUL), and T-stenting (T-PR) two-stent techniques, all deployed by a cardiologist in coronary models. Particle image velocimetry was used to obtain velocity and pressure fields. Wall shear stress (WSS), oscillatory shear index, residence times, and drag and compliance metrics were evaluated and compared against an un-stented case. The results of this study demonstrate that while PSB is preferred, both it and T-PR yielded detrimental hemodynamic effects such as low WSS values. CRU provided polarizing and unbalanced results. CUL demonstrated a symmetric flow field, balanced WSS distribution, and ultimately the most favorable hemodynamic environment.

  6. Crush implantation of a self-expanding interwoven stent over a subintimally recanalized standard stent in a TASC D lesion of the superficial femoral artery.

    PubMed

    Vogel, B; Strothmeyer, A; Cebola, R; Katus, H; Blessing, E

    2012-11-01

    We demonstrate feasibility of implantation of a self-expanding interwoven nitinol stent in a claudicant, where recanalization attempt of a heavily calcified, occluded superficial femoral artery (TASC D lesion) was complicated by a previously implanted, fractured standard stent. Wire passage through the occlusion and beyond the fractured stent could only be achieved through the subintimal space. A dedicated reentry device was used to allow distal wire entry into the true lumen at the level of the popliteal artery. Despite crushing of the fractured stent with a series of increasingly sized standard balloons, a significant recoil remainded in the area of the crushed stent. To secure patency of the femoro-popliteal artery we therefore decided to implant the novel self-expanding interwoven nitinol stent (Supera Veritas (TM), IDEV), whose unique feature is an exceptional high radial strength. Patient presented asymptomatic without any impairment of his walking capacity at three month follow up and duplex ultrasound confirmed patency of the stent. Subintimal recanalizations can be complicated by previously implanted stents, in particular in the presence of stent fracture, where intraluminal wire passage often can not be achieved. Considering the high radial strength and fracture resistance, interwoven nitinol stents represent a good treatment option in those challenging cases and they can be used to crush standard nitinol and ballonexpandable stents. PMID:23129042

  7. Association between cholesterol efflux capacity and coronary restenosis after successful stent implantation.

    PubMed

    Imaizumi, Satoshi; Miura, Shin-Ichiro; Takata, Kohei; Takamiya, Yosuke; Kuwano, Takashi; Sugihara, Makoto; Ike, Amane; Iwata, Atsushi; Nishikawa, Hiroaki; Saku, Keijiro

    2016-08-01

    The measurement of high-density lipoprotein (HDL) functionality could be useful for identifying patients who have an increased risk of coronary restenosis after stent implantation. In the present study, we elucidates whether HDL functionality can predict restenosis. The participants included 48 consecutive patients who had stable angina and were successfully implanted with a drug-eluting stent (DES) or bare-metal stent. Follow-up coronary angiography was performed after 6-8 months of stenting. Cholesterol efflux and the anti-inflammatory capacity of HDL were measured before stenting (at baseline) and at follow-up. The mean age was 64 ± 11 years and the body mass index was 24 ± 3 kg/m(2). While HDL cholesterol (HDL-C) significantly increased from baseline to follow-up, there was no significant association between HDL-C level at baseline and in-stent late loss. Cholesterol efflux capacity was significantly increased from baseline to follow-up. The efflux capacity at baseline was negatively correlated with in-stent late loss, whereas the anti-oxidative activity of HDL at baseline was not associated with in-stent late loss. We analyzed the predictors of in-stent late loss using independent variables (efflux capacity and anti-oxidative capacity at baseline in addition to age, gender, HDL-C and low-density lipoprotein cholesterol at baseline, hypertension, diabetes mellitus, smoking, lesion length and DES implantation, history of myocardial infarction and prior percutaneous coronary intervention) by a multiple regression analysis. The efflux capacity at baseline was only independently associated with in-stent late loss. In conclusion, cholesterol efflux capacity at baseline could predict coronary restenosis in patients with successful stent implantation.

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

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

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

  9. Comparison of Full Lesion Coverage versus Spot Drug-Eluting Stent Implantation for Coronary Artery Stenoses

    PubMed Central

    Kim, Seunghwan; Yun, Kyeong Ho; Shin, Dong-Ho; Kim, Jung-Sun; Kim, Byeong-Keuk; Ko, Young-Guk; Choi, Donghoon; Jang, Yangsoo

    2014-01-01

    Purpose The aim of this study was to evaluate and compare the long-term clinical outcomes of the spot drug-eluting stent (DES) implantation strategy, which is used to minimize implanted stent length and the number of stents, versus full lesion coverage for treatment of coronary artery stenoses. Materials and Methods We evaluated 1-year clinical outcomes of 1619 patients with stent implantation for a single coronary lesion. They were divided into two groups: those treated by full lesion coverage (n=1200) and those treated with the spot stenting strategy (n=419). The combined occurrence of 1-year target vessel failure (TVF), including cardiac death, target-vessel related myocardial infarction, or ischemia-driven target-vessel revascularization was evaluated. Results The spot DES implantation group had a shorter stent length (23.14±9.70 mm vs. 25.44±13.24 mm, respectively; p<0.001) and a fewer number of stents (1.09±0.30 vs. 1.16±0.41, respectively; p<0.001), even though the average lesion length was similar to the full lesion coverage group (21.36±10.30 mm vs. 20.58±10.97 mm, respectively; p=0.206). Spot DES implantation was superior to full DES coverage with respect to 1-year TVF (1.4% vs. 3.3%, p=0.044). Cox proportional hazard model analysis showed that the risk for 1-year TVF was almost 60% lower among patients who received spot DESs compared to those who received full DES coverage after adjustment for other risk factors (HR=0.40, 95% confidence interval=0.17-0.98; p=0.046). Conclusion Minimizing stent length and the number of stents with overlapping by spot DES implantation may result in reduced rates of 1-year TVF, compared with full DES coverage. PMID:24719123

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

    SciTech Connect

    Letocart, Vincent Fau, Georges Tirouvanziam, Ashok; Toquet, Claire; Al Habash, Oussama Guerin, Patrice; Rousseau, Herve; Crochet, Dominique

    2013-06-15

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

  11. Late pseudocoarctation syndrome after stent-graft implantation for traumatic aortic rupture.

    PubMed

    Letocart, Vincent; Fau, Georges; Tirouvanziam, Ashok; Toquet, Claire; Al Habash, Oussama; Guerin, Patrice; Rousseau, Hervé; Crochet, Dominique

    2013-06-01

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

  12. Combined Arterial Infusion and Stent Implantation Compared with Metal Stent Alone in Treatment of Malignant Gastroduodenal Obstruction

    SciTech Connect

    Wang Zhongmin; Chen Kemin; Gong Ju; Zheng Yunfeng; Wang Tianxiang

    2009-09-15

    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 time 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

  13. Popliteal artery aneurysm treated with implantation of a covered stent graft (fluency(®)) reinforced with a nitinol stent (S.M.A.R.T. (®)).

    PubMed

    Nishi, Masahiro; Zen, Kan; Yamaguchi, Shinichiro; Asada, Satoshi; Kambayashi, Daisuke

    2016-10-01

    A 60-year-old man was admitted for right knee pain provoked by an enlarging popliteal artery aneurysm (PAA) after endovascular therapy for thromboembolism in the right popliteal artery. The PAA was treated with implantation of a covered stent graft (Fluency(®)); however, acute thromboembolism occurred 6 months after the intervention. Therefore, we implanted a nitinol stent (S.M.A.R.T.(®)) in the proximal part of the covered stent where the major hinge point existed in addition to a stent fracture. No vascular event occurred during 4.5 years of follow-up.

  14. Hemodynamic Alterations after Stent Implantation in 15 Cases of Intracranial Aneurysms

    PubMed Central

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

    2016-01-01

    Background Stent-assisted coiling technology has been widely used in the treatment of intracranial aneurysms. In current study, we investigated the intra-aneurysmal hemodynamic alterations after stent implantation and its association with aneurysm location. Methods We first retrospectively studied 15 aneurysm cases (8 internal carotid artery-ophthalmic artery (ICA-OphA) aneurysms and 7 posterior communicating artery (PcoA) aneurysms) treated with Enterprise stents and coils. Then based on patient-specific geometries before and after stenting, we built virtual stenting computational fluid dynamics (CFD) simulation models. Results Before and after stent deployment, the average Wall Shear Stress (WSS) on the aneurysmal sac at systolic peak changed from 7.04 Pa (4.14 Pa, 15.77 Pa) to 6.04 Pa (3.86 Pa, 11.13 Pa), P = 0.001; and the spatially averaged value of flow velocity in the perpendicular plane of aneurysm dropped from 0.5 m/s (0.28 m/s, 0.7 m/s) to 0.33 m/s (0.25 m/s, 0.49 m/s), P = 0.001, respectively. Post-stent implantation, WSS in ICA-OphA aneurysms and PcoA aneurysms decreased by 14.4% (P = 0.012) and 16.6% (P = 0.018) respectively, and flow velocity also reduced by 10.3% (P = 0.029) and 10.5% (P = 0.013), respectively. Changes in WSS, flow velocity, and pressure were not significantly different between ICA-OphA aneurysms and PcoA aneurysms (P > 0.05). Stent implantation did not significantly change the peak systolic pressure in both aneurysm types. Conclusion After stent implantation, intra-aneurysmal flow velocity and WSS decreased independent of aneurysm type (ICA-OphA and PcoA). Little change was observed on peak systolic pressure. PMID:26746828

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

    SciTech Connect

    Hautmann, Hubert; Rieger, Johannes; Huber, Rudolf M.; Pfeifer, Klaus J.

    1999-03-15

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

  16. In-stent thrombosis after 68 months of implantation inspite of continuous dual antiplatelet therapy: a case report

    PubMed Central

    2010-01-01

    Lately, there has been an increased incidence of late stent thrombosis; especially following Drug eluting stent (DES) implantation. Several factors are associated with an increased risk of stent thrombosis, including the procedure itself, patient and lesion characteristics, stent design, and premature cessation of anti-platelet drugs. We present a case of late stent thrombosis (LST) following DES implantation after a period of 68 months, making it the longest reported case of LST reported in the literature, despite the use of dual anti-platelet therapy. PMID:20178570

  17. Improved vascular healing after the successful treatment of very late sirolimus-eluting stent thrombosis with a bare metal stent implantation - A serial optical coherence tomography study.

    PubMed

    Bouki, Konstantina P; Vlad, Delia; Riga, Maria; Stergiouli, Ifigenia; Toutouzas, Konstantinos P

    2016-01-01

    We present the case of a patient with non-ST-elevated myocardial infarction due to very late stent thrombosis 2 years after a sirolimus-eluting stent implantation (SES). Optical coherence tomography (OCT) imaging identified vessel wall destruction of the whole stented coronary segment with multiple cavity formations along the entire stent length, severe strut malapposition and thrombi. The patient was treated successfully with the implantation of a bare metal stent (BMS). Follow-up OCT imaging at 12 months revealed the improvement of vascular healing with complete re-endothelialization of the distal parts of the new BMS, while the stent body remained partly uncovered, suggesting vascular toxicity due to the old SES. PMID:27445030

  18. [Endovascular stent implantation as a treatment for iliac artery disease].

    PubMed

    Tetteroo, E; van Engelen, A D; van der Graaf, Y; Mali, W P

    2000-01-22

    A stent is an endovascular prosthesis that may be used in the treatment of intermittent claudication caused by lesions of the A. iliaca communis and the A. iliaca externa in which earlier balloon dilatation has proved insufficiently effective. The expansion is caused by inflation of an angioplasty balloon (plastic remodelling: Palmaz stent) or by self-expansion due to elastic transformation as in the Wail stent or to thermic memory metal, as in the Memotherm stent. Evaluation of the literature shows that stent placement is a safe method of treatment. The proportion of initial technical success appears to be higher than that of balloon angioplasty, especially in the treatment of total occlusions. The haemodynamic situation immediately after treatment also appears to be better in case of stent placement. Long-term comparison of the clinical efficacy is not well possible because the published studies differ with regard to patient population, definition of indication and criteria of success. PMID:10668541

  19. Optical coherence tomography to evaluate coronary stent implantation and complications.

    PubMed

    Hayat, Umair; Thondapu, Vikas; Ul Haq, Muhammad Asrar; Foin, Nicolas; Jang, Ik-Kyung; Barlis, Peter

    2015-08-01

    Coronary optical coherence tomography (OCT) is now an established imaging technique in many catheterization laboratories worldwide. With its near-histological view of the vessel wall and lumen interface, it offers unprecedented imaging quality to improve our understanding of the pathophysiology of atherosclerosis, plaque vulnerability, and vascular biology. Not only is OCT used to accurately detect atherosclerotic plaque and optimize stent position, but it can further characterize plaque composition, quantify stent apposition, and assess stent tissue coverage. Given that its resolution of 15 μm is well above that of angiography and intravascular ultrasound, OCT has become the invasive imaging method of choice to examine the interaction between stents and the vessel wall. This review focuses on the application of OCT to examine coronary stents, the mechanisms of stent complications, and future directions of OCT-guided intervention. PMID:26247272

  20. Transpulmonary echocardiography to guide stent implantation into coarctation of the aorta.

    PubMed

    Teramachi, Yozo; Suda, Kenji; Yoshimoto, Hironaga; Kishimoto, Shintaro; Kudo, Yoshiyuki; Iemura, Motofumi

    2015-05-01

    Although stent implantation into aortic coarctation has been performed solely under fluoroscopy, we successfully applied intracardiac echocardiography (ICE) to guide this procedure in a 13-year-old patient. Placing an intracardiac echocardiographic catheter in the left pulmonary artery facing upward, we readily visualized the precise anatomy of coarctation, measured the pressure gradient, and monitored the stent inflation process. This report suggests a new application of ICE for intervention with structural and vascular diseases other than interatrial septum.

  1. Everolimus-induced Pneumonitis after Drug-eluting Stent Implantation: A Case Report

    SciTech Connect

    Sakamoto, Susumu Kikuchi, Naoshi; Ichikawa, Atsuo; Sano, Go; Satoh, Keita; Sugino, Keishi; Isobe, Kazutoshi; Takai, Yujiro; Shibuya, Kazutoshi; Homma, Sakae

    2013-08-01

    Despite the wide use of everolimus as an antineoplastic coating agent for coronary stents to reduce the rate of restenosis, little is known about the health hazards of everolimus-eluting stents (EES). We describe a case of pneumonitis that developed 2 months after EES implantation for angina. Lung pathology demonstrated an organizing pneumonia pattern that responded to corticosteroid therapy. Although the efficacy of EES for ischemic heart disease is well established, EES carries a risk of pneumonitis.

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

    PubMed Central

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

    2016-01-01

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

  3. 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. PMID:26438449

  4. 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.

  5. 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

  6. Intravascular ultrasound characterization of the "black hole" phenomenon after drug-eluting stent implantation.

    PubMed

    Costa, Marco A; Sabate, Manel; Angiolillo, Dominick J; Jimenez-Quevedo, Pilar; Teirstein, Paul; Carter, Andrew; Leon, Martin B; Moses, Jeffrey; Zenni, Martin; Yakubov, Steven; Guzman, Luis A; Gilmore, Paul; Macaya, Carlos; Bass, Theodore A

    2006-01-15

    An intraluminal echolucent tissue, dubbed "black hole," has been identified by intravascular ultrasonography after intracoronary brachytherapy. This study reports the characteristics and incidence of the black hole in patients treated with drug-eluting stent implantation using a sirolimus-eluting stent (SES). We included intravascular ultrasound data from the Compassionate Use of Sirolimus-Eluting Stent (SECURE, n = 61 lesions) registry, a study involving patients in whom previous brachytherapy had failed, and the DIABETES trial (n = 165 lesions), a multicenter, randomized study comparing SES versus bare metal stents in diabetic patients. Intravascular ultrasound follow-up was scheduled at 8 months (SECURE trial, post-brachytherapy population) and 9 months (DIABETES trial). In the SECURE population, a black hole was observed in 10 patients (19.6%). Seven black hole segments had significant intimal hyperplasia (> 10%). A black hole accounted for 27% of total intraluminal tissue. In the DIABETES trial, 2 patients (2.5%) in the SES group and none in the bare metal stent group showed echolucent intimal hyperplasia. In conclusion, a black hole occurred frequently after implantation of a SES in patients in whom intracoronary brachytherapy had previously failed. Black holes were also identified in a nonirradiated population, although the incidence was lower than in the post-brachytherapy patients. Bare metal stents were not associated with this phenomenon.

  7. 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.

  8. Persistent High Restenosis After Local Intrawall Delivery of Long-Acting Steroids Before Coronary Stent Implantation.

    PubMed

    Reimers; Moussa; Akiyama; Kobayashi; Albiero; Di Francesco L; Di Mario C; Colombo

    1998-07-01

    OBJECTIVE: This pilot study was performed to evaluate the feasibility and safety of intrawall delivery of long acting steroids before stent implantation, testing the efficacy of this treatment in reducing intimal hyperplasia in lesions at high risk for restenosis. METHODS: In 24 patients (40 lesions) local intrawall drug delivery of methylprednisolone acetate, using a new catheter device, was attempted before elective stent implantation. Treated lesions were compared to a matched control group. RESULTS: Lesions were classified AHA/ACC type C in 47% of cases, had a mean lesion length of 13.6 +/- 9.1 mm, and a mean vessel diameter of 2.85 +/- 0.44 mm. In 9 cases (25%) chronic total occlusions were treated. Methylprednisolone acetate (mean 60 +/- 23 mg) was delivered in 36 lesions (21 patients; delivery success 90%) in the remaining 4 lesions (10%) the delivery device did not cross the lesion. After drug delivery 46 stents were implanted (1.2 stent/lesion; stented segment length 30.1 +/- 18.8 mm) using high pressure for stent expansion (mean 16.4 +/- 3.1 atm). Intracoronary ultrasound guidance was used in 64% of cases. Procedural and in-hospital complications were: Two non Q wave myocardial infarctions (8%) and one (3%) subacute stent thrombosis. Angiographic follow-up was obtained in all 36 treated lesions (100%) and the angiographic restenosis rate (³ 50% diameter stenosis) was 39%. A reduction of the incidence of restenosis compared to the matched control group was not observed. CONCLUSIONS: Long acting steroids could be delivered locally with high success and low complication rates. The restenosis rate remained high in a subset of unfavorable lesions with high risk for restenosis.

  9. Comparison of Endoscopic Vacuum Therapy and Endoscopic Stent Implantation With Self-Expandable Metal Stent in Treating Postsurgical Gastroesophageal Leakage.

    PubMed

    Hwang, Jae J; Jeong, Yeon S; Park, Young S; Yoon, Hyuk; Shin, Cheol M; Kim, Nayoung; Lee, Dong H

    2016-04-01

    The aim of the present study was to evaluate the more effective therapy for the postsurgical gastroesophageal leakage by a head-to-head comparison of endoscopic vacuum therapy (EVT) and endoscopic stent implantation with self-expandable metal stent (E-SEMS). In this hospital-based, retrospective, observative study, the patients were classified into 2 groups. Those treated with EVT were assigned to the EVT group (n = 7), and those treated with E-SMS were assigned to the E-SEMS group (n = 11). We evaluated the clinical characteristics and treatment outcomes between the 2 groups. All 7 patients (100%) were treated with EVT, but only 7 of 11 patients (63.6%) in the stenting group were treated successfully. The median time to clinical success was 19.5 (5-21) days in the EVT group and 27.0 (3-84) days in the E-SEMS group. The median hospital stay was 37.1 (13-128) days in the EVT group and 87.3 (17-366) days in the E-SEMS group. The complicaion rate was lower in the EVT group (0/7, 0.0%) than that in the E-SEMS group (6/11, 54.5%) with statistically significant difference (P = 0.042). EVT is more effective and has fewer adverse effects than E-SMS therapy as a treatment for postsurgical gastroesophageal leakage.

  10. Comparison of Endoscopic Vacuum Therapy and Endoscopic Stent Implantation With Self-Expandable Metal Stent in Treating Postsurgical Gastroesophageal Leakage

    PubMed Central

    Hwang, Jae J.; Jeong, Yeon S.; Park, Young S.; Yoon, Hyuk; Shin, Cheol M.; Kim, Nayoung; Lee, Dong H.

    2016-01-01

    Abstract The aim of the present study was to evaluate the more effective therapy for the postsurgical gastroesophageal leakage by a head-to-head comparison of endoscopic vacuum therapy (EVT) and endoscopic stent implantation with self-expandable metal stent (E-SEMS). In this hospital-based, retrospective, observative study, the patients were classified into 2 groups. Those treated with EVT were assigned to the EVT group (n = 7), and those treated with E-SMS were assigned to the E-SEMS group (n = 11). We evaluated the clinical characteristics and treatment outcomes between the 2 groups. All 7 patients (100%) were treated with EVT, but only 7 of 11 patients (63.6%) in the stenting group were treated successfully. The median time to clinical success was 19.5 (5–21) days in the EVT group and 27.0 (3–84) days in the E-SEMS group. The median hospital stay was 37.1 (13–128) days in the EVT group and 87.3 (17–366) days in the E-SEMS group. The complicaion rate was lower in the EVT group (0/7, 0.0%) than that in the E-SEMS group (6/11, 54.5%) with statistically significant difference (P = 0.042). EVT is more effective and has fewer adverse effects than E-SMS therapy as a treatment for postsurgical gastroesophageal leakage. PMID:27100431

  11. Comparison of Endoscopic Vacuum Therapy and Endoscopic Stent Implantation With Self-Expandable Metal Stent in Treating Postsurgical Gastroesophageal Leakage.

    PubMed

    Hwang, Jae J; Jeong, Yeon S; Park, Young S; Yoon, Hyuk; Shin, Cheol M; Kim, Nayoung; Lee, Dong H

    2016-04-01

    The aim of the present study was to evaluate the more effective therapy for the postsurgical gastroesophageal leakage by a head-to-head comparison of endoscopic vacuum therapy (EVT) and endoscopic stent implantation with self-expandable metal stent (E-SEMS). In this hospital-based, retrospective, observative study, the patients were classified into 2 groups. Those treated with EVT were assigned to the EVT group (n = 7), and those treated with E-SMS were assigned to the E-SEMS group (n = 11). We evaluated the clinical characteristics and treatment outcomes between the 2 groups. All 7 patients (100%) were treated with EVT, but only 7 of 11 patients (63.6%) in the stenting group were treated successfully. The median time to clinical success was 19.5 (5-21) days in the EVT group and 27.0 (3-84) days in the E-SEMS group. The median hospital stay was 37.1 (13-128) days in the EVT group and 87.3 (17-366) days in the E-SEMS group. The complicaion rate was lower in the EVT group (0/7, 0.0%) than that in the E-SEMS group (6/11, 54.5%) with statistically significant difference (P = 0.042). EVT is more effective and has fewer adverse effects than E-SMS therapy as a treatment for postsurgical gastroesophageal leakage. PMID:27100431

  12. A case of an occlusive right coronary artery dissection after stent implantation: dilemmas and challenges.

    PubMed

    Panoulas, Vasileios F; Figini, Filippo; Giustino, Gennaro; Carlino, Mauro; Chieffo, Alaide; Latib, Azeem; Colombo, Antonio

    2015-01-01

    A 53-year-old man with stable angina had a staged percutaneous coronary intervention to a critical focal stenosis of the mid-segment of the right coronary artery (RCA). Two hours after successful RCA stent implantation, the patient re-presented with inferior ST elevation secondary to acute dissection originating at the distal edge of the stent, causing subtotal occlusion of the distal RCA. The patient had TIMI-2 flow in the posterolateral branch and occlusion of the posterior descending artery. This case describes the procedural challenges the operators were faced with and successful use of the "rescue STAR" technique as a last resort. PMID:25589705

  13. Simultaneous stent implantation for coarctation of the aorta and closure of patent ductus arteriosus using the Amplatzer duct occluder.

    PubMed

    Hakim, F; Hawelleh, A A; Goussous, Y; Hijazi, Z M

    1999-05-01

    We report on a 13-year-old girl with coarctation of the aorta and patent ductus arteriosus who underwent successful simultaneous stent implantation for the coarctation and catheter closure of the ductus using an Amplatzer duct occluder. PMID:10385155

  14. [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.

  15. Usefulness of Everolimus-Eluting Coronary Stent Implantation in Patients on Maintenance Hemodialysis.

    PubMed

    Ikari, Yuji; Kyono, Hiroyuki; Isshiki, Takaaki; Ishizuka, Shuichi; Nasu, Kenya; Sano, Koichi; Okada, Hisayuki; Sugano, Teruyasu; Uehara, Yoshiki

    2015-09-15

    The outcomes of second-generation drug-eluting stent (DES) are unknown in patients on maintenance hemodialysis (HD) although HD has been reported as a strong predictor of adverse outcome after the first-generation DES implantation. The OUCH-PRO Study is a prospective multicenter single-arm registry design to study clinical and angiographic outcomes after everolimus-eluting stent (EES). Patients who underwent maintenance HD were prospectively enrolled at the time of elective coronary intervention using EES. Quantitative coronary angiography was performed in an independent core laboratory. The primary end point was the occurrence of target vessel failure (TVF) defined as cardiac death, myocardial infarction (MI), and target vessel revascularization at 1 year. A total of 123 patients were enrolled and 161 EES were implanted. The TVF rate at 1 year was 18% (4% cardiac death, 0% MI, 17% target vessel revascularization). No stent thrombosis was documented. Other clinical events at 1 year were 3% noncardiac death, 3% stroke, and 9% non-target-vessel revascularization. Late lumen loss in stent was 0.37 ± 0.63 mm at 8 months. In conclusion, EES had a high TVF rate and great late lumen loss in patients on HD compared with previous huge EES data in non-HD patients. PMID:26219496

  16. Management of Biliary Neoplastic Obstruction with Two Different Metallic Stents Implanted in One Session

    SciTech Connect

    Gandini, Roberto; Fabiano, S. Pipitone, Vincenzo; Spinelli, Alessio; Reale, Carlo Andrea; Colangelo, Vittorio; Pampana, Enrico; Romagnoli, Andrea; Simonetti, Giovanni

    2005-01-15

    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 patients (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.

  17. Wall shear stress in the development of in-stent restenosis revisited. A critical review of clinical data on shear stress after intracoronary stent implantation.

    PubMed

    Jenei, Csaba; Balogh, Emília; Szabó, Gábor Tamás; Dézsi, Csaba András; Kőszegi, Zsolt

    2016-01-01

    The average wall shear stress (WSS) is in 1 Pa range in coronary arteries, while the stretching effect of an implanted coronary stent can generate up to 3 × 105 times higher circumferential stress in the vessel wall. It is widely accepted that WSS plays a critical role in the development of restenosis after coronary stent implantation, but relevant clinical endpoint studies are lack-ing. Fluid dynamics modeling suggests an association between WSS and intimal hyperplasia, however, such an association is not established when the compensating healing process becomes an overshoot phenomenon. This review summarizes available clinical results and concepts of potential clinical importance. PMID:27439365

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

    PubMed

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

    2003-07-01

    The stimulation of endothelial cells by arterial wall shear stress (WSS) plays a central role in restenosis. The fluid-structure interaction between stent wire and blood flow alters the WSS, particularly between stent struts. We have designed an in vitro model of struts of an intra-vascular prosthesis to study blood flow through a 'stented' section. The experimental artery consisted of a transparent square section test vein, which reproduced the strut design (100x magnifying power). A programmable pump was used to maintain a steady blood flow. Particle image velocimetry method was used to measure the flow between and over the stent branches, and to quantify WSS. Several prosthesis patterns that were representative of the total stent strut geometry were studied in a greater detail. We obtained WSS values of between -1.5 and 1.5Pa in a weak SS area which provided a source of endothelial stimulation propitious to restenosis. We also compared two similar patterns located in two different flow areas (one at the entry of the stent and one further downstream). We only detected a slight difference between the weakest SS levels at these two sites. As the endothelial proliferation is greatly influenced by the SS, knowledge of the SS modification induced by the stent implantation could be of importance for intra-vascular prostheses design optimisation and thus can help to reduce the restenosis incidence rate. PMID:12757808

  19. Focal wall overstretching after high-pressure coronary stent implantation does not influence restenosis.

    PubMed

    Nakamura, S; Di Francesco, L; Finci, L; Reimers, B; Adamian, M; Di Mario, C; Colombo, A

    1999-09-01

    To determine if vessel wall overstretching during coronary stenting is associated with a higher restenosis rate, the intravascular ultrasound morphological evaluation was performed following ultrasound criteria. A total of 468 lesions with successful coronary Palmaz-Schatz stenting guided by intravascular ultrasound were classified into the no overstretching group (n = 295) and the overstretching group (n = 147). There were 26 lesions not classifiable due to the poststent morphology. Balloon-to-vessel ratio was 1.12 +/- 0.17 in the no focal overstretching group and 1. 20 +/- 0.20 in the overstretching group (P < 0.0002). Follow-up angiogram was performed in 77% of no focal overstretching group and in 75% of the focal overstretching group. The restenosis rate of the no focal overstretching group was 19.8% and 20.9% in the focal overstretching group, respectively (P = 0.65). Focal overstretching was more frequent following balloon oversizing. No increase in restenosis rate, found in focal overstretched stented lesions, leads us to the hypothesis of a regulation of smooth-muscle-cell proliferation activated by the normalization of blood flow and of shear stress, when stent implantation succeeds in optimally improving the lumen. Cathet. Cardiovasc. Intervent. 48:24-30, 1999.

  20. In-vitro study on the accuracy of a simple-design CT-guided stent for dental implants

    PubMed Central

    Huh, Young-June; Choi, Bo-Ram; Huh, Kyung-Hoe; Yi, Won-Jin; Heo, Min-Suk; Lee, Sam-Sun

    2012-01-01

    Purpose An individual surgical stent fabricated from computed tomography (CT) data, called a CT-guided stent, would be useful for accurate installation of implants. The purpose of the present study was to introduce a newly developed CT-guided stent with a simple design and evaluate the accuracy of the stent placement. Materials and Methods A resin template was fabricated from a hog mandible and a specially designed plastic plate, with 4 metal balls inserted in it for radiographic recognition, was attached to the occlusal surface of the template. With the surgical stent applied, CT images were taken, and virtual implants were placed using software. The spatial positions of the virtually positioned implants were acquired and implant guiding holes were drilled into the surgical stent using a specially designed 5-axis drilling machine. The surgical stent was placed on the mandible and CT images were taken again. The discrepancy between the central axis of the drilled holes on the second CT images and the virtually installed implants on the first CT images was evaluated. Results The deviation of the entry point and angulation of the central axis in the reference plane were 0.47±0.27 mm, 0.57±0.23 mm, and 0.64±0.16°, 0.57±0.15°, respectively. However, for the two different angulations in each group, the 20° angulation showed a greater error in the deviation of the entry point than did the 10° angulation. Conclusion The CT-guided template proposed in this study was highly accurate. It could replace existing implant guide systems to reduce costs and effort. PMID:23071963

  1. Neointimal hyperplasia persists at six months after sirolimus-eluting stent implantation in diabetic porcine

    PubMed Central

    Zhang, Qi; Lu, Lin; Pu, LiJin; Zhang, RuiYan; Shen, Jie; Zhu, ZhengBing; Hu, Jian; Yang, ZhenKun; Chen, QiuJin; Shen, WeiFeng

    2007-01-01

    Background Observational clinical studies have shown that patients with diabetes have less favorable results after percutaneous coronary intervention compared with the non-diabetic counterparts, but its mechanism remains unclear. The aim of this study was to examine the changes of neointimal hyperplasia after sirolimus-eluting stent (SES) implantation in a diabetic porcine model, and to evaluate the impact of aortic inflammation on this proliferative process. Methods Diabetic porcine model was created with an intravenous administration of a single dose of streptozotocin in 15 Chinese Guizhou minipigs (diabetic group); each of them received 2 SES (Firebird, Microport Co, China) implanted into 2 separated major epicardial coronary arteries. Fifteen non-diabetic minipigs with SES implantation served as controls (control group). At 6 months, the degree of neointimal hyperplasia was determined by repeat coronary angiography, intravascular ultrasound (IVUS) and histological examination. Tumor necrosis factor (TNF)-α protein level in the aortic intima was evaluated by Western blotting, and TNF-α, interleukin (IL)-1β and IL-6 mRNA levels were assayed by reverse transcription and polymerase chain reaction. Results The distribution of stented vessels, diameter of reference vessels, and post-procedural minimal lumen diameter were comparable between the two groups. At 6-month follow-up, the degree of in-stent restenosis (40.4 ± 24.0% vs. 20.2 ± 17.7%, p < 0.05), late lumen loss (0.33 ± 0.19 mm vs. 0.10 ± 0.09 mm, p < 0.001) by quantitative angiography, percentage of intimal hyperplasia in the stented area (26.7 ± 19.2% vs. 7.3 ± 6.1%, p < 0.001) by IVUS, and neointimal area (1.59 ± 0.76 mm2 vs. 0.41 ± 0.18 mm2, p < 0.05) by histological examination were significantly exacerbated in the diabetic group than those in the controls. Significant increases in TNF-α protein and TNF-α, IL-1β and IL-6 mRNA levels were observed in aortic intima in the diabetic group

  2. The effect of implantation of aortic stents on compliance and blood flow. An experimental study in pigs.

    PubMed

    Pihkala, J; Thyagarajan, G K; Taylor, G P; Nykanen, D; Benson, L N

    2001-03-01

    Balloon dilation of coarctation of the aorta has been found to be an effective modality for treatment. Recently, in the older child and adult, implantation of endovascular stents has been considered a clinical alternative to dilation alone. Little is known, however, of the effect of implantation of stents on aortic compliance. To investigate this impact of implantation, we studied 18 piglets, divided into experimental and control groups. At median weight of 14 kg, 2 pairs of ultrasonic crystals were implanted on the aortic wall. After 1 week, all animals underwent catheterization. In the experimental group, a 3 cm long balloon expandable stent was implanted in the descending thoracic aorta between the pairs of crystals. Measurements of arterial pressure and dimensions were performed before implantation and immediately thereafter, and at follow-up catheterization. The index of stiffness, beta, and the the elastic modulus of aortic pressure-strain, were calculated as indexes of arterial compliance. The change in compliance during the period of study was not different between groups. At follow-up, no difference was observed between groups in the velocity of the aortic pulse wave, the augmentation index, or the maximum velocity of flow of blood. The stents remained patent and did not affect aortic growth or medial wall thickness. There was no difference between groups in levels of plasma renin activity and serum aldosterone. In this animal model studied over the short term, therefore, implantation of stents does not affect aortic compliance. Further studies are required to elucidate the long term effects of stents on the hemodynamics affecting the aortic wall and local flow dynamics.

  3. Effects of balloon angioplasty and stent implantation on intrarenal echo-Doppler velocimetric indices.

    PubMed

    Marana, I; Airoldi, F; Burdick, L; Alberti, C; Lovaria, A; Saccheri, S; Gazzano, G; Palatresi, S; Nador, B; Turolo, L; Morganti, A

    1998-06-01

    This study was aimed at examining whether four intrarenal echo-Doppler velocimetric indices (pulsatility and resistive indices, acceleration and acceleration time) can be useful for assessing the effects of renal artery dilation obtained with either angioplasty or stent implantation. Echo-Doppler studies were performed in 63 hypertensive patients with 68 renal artery stenoses (39 atherosclerotic and 29 fibromuscular) prior to and within five days after the dilation procedures (55 angioplasties, 13 stent implantations), which resulted in an average reduction of arterial narrowing from 79% to 20%. In 24 patients, the velocimetric indices were also examined in relationship to the venoarterial differences of plasma renin activity and of angiotensin II across the stenotic kidneys. We found that after dilation the values of the four indices had returned within the normal range in all but three arteries (one false negative for resistive index and two for acceleration time). However, decrements in acceleration time was the only factor to be significantly correlated with the reduction of arterial narrowing. Moreover, postdilation values of this index were, on average, slightly but significantly higher in arteries that at follow-up developed restenosis rather than in those that remained patent. For similar reductions in arterial narrowing the absolute changes of all indices were similar in atherosclerotic and fibromuscular stenotic arteries and, in a subset of the atheromatous arteries, were also similar after angioplasty and stent implantation. No relationship was found with the changes in the venoarterial differences of plasma renin activity and angiotensin II. It appears that these intrarenal velocimetric indices and, in particular, acceleration time reliably reflect the technical success of renal artery dilation. The acceleration time index may also be valuable for predicting the restenosis of the dilated vessel. None of the indices, however, mirrors the functional

  4. Quantification of local hemodynamic alterations caused by virtual implantation of three commercially available stents for the treatment of aortic coarctation.

    PubMed

    Kwon, Sung; Feinstein, Jeffrey A; Dholakia, Ronak J; Ladisa, John F

    2014-04-01

    Patients with coarctation of the aorta (CoA) are prone to morbidity including atherosclerotic plaque that has been shown to correlate with altered wall shear stress (WSS) in the descending thoracic aorta (dAo). We created the first patient-specific computational fluid dynamics (CFD) model of a CoA patient treated by Palmaz stenting to date, and compared resulting WSS distributions to those from virtual implantation of Genesis XD and modified NuMED CP stents, also commonly used for CoA. CFD models were created from magnetic resonance imaging, fluoroscopy and blood pressure data. Simulations incorporated vessel deformation, downstream vascular resistance and compliance to match measured data and generate blood flow velocity and time-averaged WSS (TAWSS) results. TAWSS was quantified longitudinally and circumferentially in the stented region and dAo. While modest differences were seen in the distal portion of the stented region, marked differences were observed downstream along the posterior dAo and depended on stent type. The Genesis XD model had the least area of TAWSS values exceeding the threshold for platelet aggregation in vitro, followed by the Palmaz and NuMED CP stents. Alterations in local blood flow patterns and WSS imparted on the dAo appear to depend on the type of stent implanted for CoA. Following confirmation in larger studies, these findings may aid pediatric interventional cardiologists in selecting the most appropriate stent for each patient, and ultimately reduce long-term morbidity following treatment for CoA by stenting.

  5. Optical coherence tomography derived cut-off value of uncovered stent struts to predict adverse clinical outcomes after drug-eluting stent implantation.

    PubMed

    Won, Hoyoun; Shin, Dong-Ho; Kim, Byeong-Keuk; Mintz, Gary S; Kim, Jung-Sun; Ko, Young-Guk; Choi, Donghoon; Jang, Yangsoo; Hong, Myeong-Ki

    2013-08-01

    Although the presence of uncovered struts may be associated with occurrence of stent thrombosis, the impact of uncovered struts detected routinely by optical coherence tomography (OCT) on subsequent long-term clinical outcomes remains unclear. The objective of this study was to determine the cut-off value of uncovered struts that predicted adverse clinical outcomes after drug eluting stent (DES) implantation. Major safety events (MSEs, a composite occurrence of cardiovascular death, myocardial infarction, and stent thrombosis) were evaluated in 489 DES-treated patients (535 lesions) during the median 851 days after follow-up OCT. MSEs occurred in six patients (four definite stent thrombosis and two sudden cardiac death). The best cut-off value of percentage of uncovered struts for predicting MSE was 5.9 % using the maximal χ(2) method: area under the receiver-operating characteristic curve = 0.779, 95 % confidence interval (CI) = 0.648-0.910, p = 0.019, a sensitivity of 83.3 % and a specificity of 70.3 %. Independent predictors for MSE were post-intervention minimal lumen diameter (odds ratio 0.019, 95 % CI = 0.001-0.513, p = 0.018) and percentage of uncovered struts ≥5.9 % (odds ratio 19.781, 95 % CI = 2.071-188.968, p = 0.010). A greater percentage of uncovered struts (the cut-off value of ≥5.9 % uncovered struts) might be significantly associated with occurrence of MSE after DES implantation. PMID:23615849

  6. Primary stent implantation is superior to balloon angioplasty in acute myocardial infarction: final results of the primary angioplasty versus stent implantation in acute myocardial infarction (PASTA) trial. PASTA Trial Investigators.

    PubMed

    Saito, S; Hosokawa, G; Tanaka, S; Nakamura, S

    1999-11-01

    Several studies have shown that stent implantations in acute myocardial infarction (AMI) result in better short- and long-term outcomes than primary balloon angioplasty. These results, however, have not been ascertained in randomized trials. We randomized 136 patients out of 208 patients with AMI within 12 hr from onset into two groups: 69 patients with primary balloon angioplasty (POBA group) and 67 patients with primary stent implantation (STENT group). We compared the incidences of major cardiac events (repeat MI, target lesion revascularization, and cardiac death) and angiographic parameters during hospitalization and follow-up periods up to 12 months in these two groups. There was no significant difference in the reperfusion success rates. The incidences of major cardiac events were lower in the STENT group than in the POBA group during hospitalization, the first 6 months and 12 months (6% vs. 19%, P = 0.023; 21% vs. 46%, P < 0.0001; 22% vs. 49%, P = 0.0011). Minimum lumen diameters were significantly bigger in the STENT group than the POBA group at predischarge angiogram and 6-month follow-up (2.85 +/- 0.62 vs. 2.08 +/- 0.82 mm, P < 0.0001; 2.24 +/- 0.64 vs. 1.72 +/- 0.76, P = 0.002). Restenosis rates at 6-month follow-up were significantly lower in the STENT group than in the POBA group (17% vs. 37.5%, P = 0.02). In selected patients with AMI, primary stent implantation results in a lower incidence of major cardiac events during the first 12 months, postprocedure, and less frequent 6-month restenosis than primary balloon angioplasty.

  7. Bridge therapy or standard treatment for urgent surgery after coronary stent implantation: Analysis of 314 patients.

    PubMed

    De Servi, Stefano; Morici, Nuccia; Boschetti, Enrico; Rossini, Roberta; Martina, Paola; Musumeci, Giuseppe; D'Urbano, Maurizio; Lazzari, Ludovico; La Vecchia, Carlo; Senni, Michele; Klugmann, Silvio; Savonitto, Stefano

    2016-05-01

    Intravenous administration of a short acting glycoprotein IIb/IIIa inhibitor has been proposed as a bridge to surgery in patients on dual antiplatelet treatment, but data in comparison with other treatment options are not available. We conducted a retrospective analysis of consecutive patients who underwent un-deferrable, non-emergency surgery after coronary stenting. The bridge therapy was performed after discontinuation of the oral P2Y12 inhibitor by using i.v. tirofiban infusion. Net Adverse Clinical Events (NACE) was the primary outcome. We analyzed 314 consecutive patients: the bridge strategy was performed in 87 patients, whereas 227 were treated with other treatment options and represent the control group. Thirty-day NACE occurred in 8% of patients in the bridge group and in 22.5% in the control group (p < 0.01). Bridge therapy was associated with decreased 30-day NACE rate [Odds ratio (OR) 0.30; 95% confidence interval (CI) 0.13-0.39; p < 0.01], particularly when the time interval between stenting and surgery was ≤ 60 days (OR 0.09, 95% CI 0.01-0.72; p = 0.02). There were no cases of stent thrombosis in the bridge group and 3 (1.3%) in the control group. Bridge therapy was associated with decreased events rates as compared to both patients with and without P2Y12 inhibitors discontinuation in the control group. After adjustment for the most relevant covariates, the favorable effect of the bridge therapy was not materially modified. In conclusion, perioperative bridge therapy using tirofiban was associated with reduced 30-day NACE rate, particularly when surgery was performed within 60 days after stent implantation.

  8. Interleukin-6 and Asymmetric Dimethylarginine Are Associated with Platelet Activation after Percutaneous Angioplasty with Stent Implantation

    PubMed Central

    Gremmel, Thomas; Perkmann, Thomas; Kopp, Christoph W.; Seidinger, Daniela; Eichelberger, Beate; Koppensteiner, Renate; Steiner, Sabine; Panzer, Simon

    2015-01-01

    Data linking in vivo platelet activation with inflammation and cardiovascular risk factors are scarce. Moreover, the interrelation between endothelial dysfunction as early marker of atherosclerosis and platelet activation has not been studied, so far. We therefore sought to investigate the associations of inflammation, endothelial dysfunction and cardiovascular risk factors with platelet activation and monocyte-platelet aggregate (MPA) formation in 330 patients undergoing angioplasty with stent implantation for atherosclerotic cardiovascular disease. P-selectin expression, activation of glycoprotein IIb/IIIa and MPA formation were determined by flow cytometry. Interleukin (IL)-6, high sensitivity C-reactive protein and asymmetric dimethylarginine (ADMA) were measured by commercially available assays. IL-6 was the only parameter which was independently associated with platelet P-selectin expression and activated GPIIb/IIIa as well as with leukocyte-platelet interaction in multivariate regression analysis (all p<0.05). ADMA was independently associated with GPIIb/IIIa activation (p<0.05). Patients with high IL-6 exhibited a significantly higher expression of P-selectin than patients with low IL-6 (p=0.001), whereas patients with high ADMA levels showed a more pronounced activation of GPIIb/IIIa than patients with low ADMA (p=0.003). In conclusion, IL-6 and ADMA are associated with platelet activation after percutaneous angioplasty with stent implantation. It remains to be established whether they act prothrombotic and atherogenic themselves or are just surrogate markers for atherosclerosis with concomitant platelet activation. PMID:25807315

  9. Interleukin-6 and asymmetric dimethylarginine are associated with platelet activation after percutaneous angioplasty with stent implantation.

    PubMed

    Gremmel, Thomas; Perkmann, Thomas; Kopp, Christoph W; Seidinger, Daniela; Eichelberger, Beate; Koppensteiner, Renate; Steiner, Sabine; Panzer, Simon

    2015-01-01

    Data linking in vivo platelet activation with inflammation and cardiovascular risk factors are scarce. Moreover, the interrelation between endothelial dysfunction as early marker of atherosclerosis and platelet activation has not been studied, so far. We therefore sought to investigate the associations of inflammation, endothelial dysfunction and cardiovascular risk factors with platelet activation and monocyte-platelet aggregate (MPA) formation in 330 patients undergoing angioplasty with stent implantation for atherosclerotic cardiovascular disease. P-selectin expression, activation of glycoprotein IIb/IIIa and MPA formation were determined by flow cytometry. Interleukin (IL)-6, high sensitivity C-reactive protein and asymmetric dimethylarginine (ADMA) were measured by commercially available assays. IL-6 was the only parameter which was independently associated with platelet P-selectin expression and activated GPIIb/IIIa as well as with leukocyte-platelet interaction in multivariate regression analysis (all p<0.05). ADMA was independently associated with GPIIb/IIIa activation (p<0.05). Patients with high IL-6 exhibited a significantly higher expression of P-selectin than patients with low IL-6 (p=0.001), whereas patients with high ADMA levels showed a more pronounced activation of GPIIb/IIIa than patients with low ADMA (p=0.003). In conclusion, IL-6 and ADMA are associated with platelet activation after percutaneous angioplasty with stent implantation. It remains to be established whether they act prothrombotic and atherogenic themselves or are just surrogate markers for atherosclerosis with concomitant platelet activation.

  10. Similar Success Rates with Bivalirudin and Unfractionated Heparin in Bare-Metal Stent Implantation

    SciTech Connect

    Hallak, Omar; Shams, S. Ali; Broce, Mike; Lavigne, P. Scott; Lucas, B. Daniel; Elhabyan, Abdul-Karim; Reyes, Bernardo J.

    2007-09-15

    Background. Unfractionated heparin (UFH) is the traditional agent utilized during percutaneous peripheral interventions (PPIs) despite its well-known limitations. Bivalirudin, a thrombin-specific anticoagulant, overcomes many of the limitations of UFH and has consistently demonstrated comparable efficacy with significantly fewer bleeding complications. The purpose of this study was to compare procedural success in patients undergoing bare-metal stent implantation for atherosclerotic blockage of the renal, iliac, and femoral arteries and receiving either bivalirudin (0.75 mg/kg bolus/1.75 mg/kg/hr infusion) or UFH (50-70 U/kg/hr bolus) as the primary anticoagulant. Methods. This study was an open-label, nonrandomized retrospective registry with the primary endpoint of procedural success. Secondary endpoints included incidence of: death, myocardial infarction (MI), urgent revascularization, amputation, and major and minor bleeding. Results. One hundred and five consecutive patients were enrolled (bivalirudin = 53; heparin = 52). Baseline demographics were comparable between groups. Patients were pretreated with clopidogrel (approx. 71%) and aspirin (approx. 79%). Procedural success was achieved in 97% and 96% of patients in the bivalirudin- and heparin-treated groups, respectively. Event rates were low and similar between groups. Conclusion. Bivalirudin maintained an equal rate of procedural success in this cohort without sacrificing patient safety. Results of this study add to the growing body of evidence supporting the safety and efficacy of bivalirudin as a possible substitute for UFH in anticoagulation during peripheral vascular bare-metal stent implantation.

  11. Coronary venous lead implantation after an evaluation by virtual histology intravascular ultrasound and stenting of a stenosis.

    PubMed

    Yamasaki, Hiro; Tada, Hiroshi; Arimoto, Takanori; Sekiguchi, Yukio; Sato, Akira; Aonuma, Kazutaka

    2013-02-01

    We describe a patient who developed coronary vein (CV) stenosis shortly (<3 months) after an initial left ventricular (LV) lead implantation with significant fibrous tissue. The virtual histological intravascular ultrasound analysis was useful for characterizing the plaque component of the stenotic lesion and formulating the strategy. A summarized review of the CV angioplasty for LV lead implantations disclosed that CV stenosis was often found in patients who had a previous history of cardiac surgery or an LV lead implantation and that a stent implantation was required to deploy the LV lead in the targeted CV in some (9.3%) patients.

  12. Long-term outcomes of intravascular ultrasound-guided implantation of bare metal stents versus drug-eluting stents in primary percutaneous coronary intervention

    PubMed Central

    Cho, Yun-Kyeong; Park, Nam-Hee; Choi, Sang-Woong; Sohn, Ji-Hyun; Cho, Hyun-Ok; Park, Hyoung-Seob; Yoon, Hyuck-Jun; Kim, Hyungseop; Nam, Chang-Wook; Kim, Yoon-Nyun; Kim, Kwon-Bae

    2014-01-01

    Background/Aims While drug-eluting stents (DESs) have shown favorable outcomes in ST-segment elevation myocardial infarction (STEMI) compared to bare metal stents (BMSs), there are concerns about the risk of stent thrombosis (ST) with DESs. Because intravascular ultrasound (IVUS) guidance may help optimize stent placement and improve outcomes in percutaneous coronary intervention (PCI) patients, we evaluated the impact of IVUS-guided BMS versus DES implantation on long-term outcomes in primary PCI. Methods In all, 239 STEMI patients received DES (n = 172) or BMS (n = 67) under IVUS guidance in primary PCI. The 3-year incidence of major adverse cardiac events (MACEs) including death, myocardial infarction (MI), target vessel revascularization (TVR), and ST was evaluated. Results There was no difference in all cause mortality or MI. However, the incidence of TVR was 23.9% with BMS versus 9.3% with DES (p = 0.005). Thus, the number of MACEs was significantly lower with DES (11.0% vs. 29.9%; p = 0.001). The incidence of definite or probable ST was not different (1.5% vs. 2.3%; p = 1.0). IVUS-guided DES implantation (hazard ratio [HR], 0.25; 95% confidence interval [CI], 0.08 to 0.78; p = 0.017), stent length (HR, 1.03; 95% CI, 1.00 to 1.06; p = 0.046), and multivessel disease (HR, 3.01; 95% CI, 1.11 to 8.15; p = 0.030) were independent predictors of MACE. Conclusions In patients treated with primary PCI under IVUS guidance, the use of DES reduced the incidence of 3-year TVR versus BMS. However, all cause mortality and MI were similar between the groups. The incidence of ST was low in both groups. PMID:24574835

  13. [Baloon angioplasty with stent implantation in recoarctation of the aorta: an attractive alternative].

    PubMed

    Saliba, Z; Aggoun, Y; Iserin, L; Massih, T A; Bonnet, D; Acar, P; Mousseaux, E; Sidi, D; Kachaner, J; Bonhoeffer, P

    2001-05-01

    The results of transcatheter balloon angioplasty in teenagers and adults with aortic recoarctation are uncertain. Therefore, there is a current trend to prefer a more complex procedure including the implantation of a stent. This study deals with 8 patients aged 7 to 25.3 years (median: 15 years), weighing 20 to 68 kg. (median: 57) and having undergone resection of an aortic coarctation during infancy (24 days to 4 years). All had their lower limb pulses diminished or abolished, elevated blood pressure at rest (and at exercise in the 5 tested patients), and left ventricular hypertrophy. MRI documented the lesion and helped to select seven patients whose stenosis was short and remote enough from the origin of the main aortic collateral. In one case, the decision to stent was taken as an emergent measure to treat an aortic dissection which appeared shortly after balloon dilatation. The effectiveness of the procedure was immediate in all patients with a 50% increase in diameter of the dilated area, total relief of the gradient, drop to normal values of the blood pressure. These good results persisted at follow-up (3-24 months) in 6 patients, with moderate hypertensive rebounds in the last 2. There were 2 technical problems (premature burst of the balloon, asymmetrical inflation of the stent like an "Eiffel Tower") that could finally be overcome and should no longer occur with the new specially designed so-called "BIB" balloons. Would long term follow-up confirm these early results, one should conclude that this method offers an attractive, safe and effective option to surgery for adolescents and adults with late recoarctation of the aorta.

  14. Impact of Insulin Resistance on Neointimal Tissue Proliferation after 2nd-Generation Drug-Eluting Stent Implantation.

    PubMed

    Komatsu, Takaaki; Yaguchi, Isao; Komatsu, Sachiko; Nakahara, Shiro; Kobayashi, Sayuki; Sakai, Yoshihiko; Taguchi, Isao

    2015-08-01

    Percutaneous coronary intervention is established as an effective treatment for patients with ischemic heart disease; in particular, drug-eluting stent implantation is known to suppress in-stent restenosis. Diabetes mellitus is an independent risk factor for restenosis, so reducing insulin resistance is being studied as a new treatment approach. In this prospective study, we sought to clarify the factors associated with in-stent restenosis after percutaneous coronary intervention, and we evaluated the homeostasis model assessment of insulin resistance (HOMA-IR) index as a predictor of restenosis. We enrolled 136 consecutive patients who underwent elective percutaneous coronary intervention at our hospital from February 2010 through April 2013. All were implanted with a 2nd-generation drug-eluting stent. We distributed the patients in accordance with their HOMA-IR index values into insulin-resistant Group P (HOMA-IR, ≥2.5; n=77) and noninsulin-resistant Group N (HOMA-IR, <2.5; n=59). Before and immediately after stenting, we measured reference diameter, minimal lumen diameter, and percentage of stenosis, and after 8 months we measured the last 2 factors and late lumen loss, all by means of quantitative coronary angiography. After 8 months, the mean minimal lumen diameter was smaller in Group P than that in Group N (1.85 ± 1.02 vs 2.37 ± 0.66 mm; P=0.037), and the mean late lumen loss was larger (0.4 ± 0.48 vs 0.16 ± 0.21 mm; P=0.025). These results suggest that insulin resistance affects neointimal tissue proliferation after 2nd-generation drug-eluting stent implantation. PMID:26413014

  15. Primary Implantation of Polyester-Covered Stent-Grafts for Transjugular Intrahepatic Portosystemic Stent Shunts (TIPSS): A Pilot Study

    SciTech Connect

    Cejna, Manfred; Thurnher, Siegfried; Pidlich, Johann; Kaserer, Klaus; Schoder, Maria; Lammer, Johannes

    1999-07-15

    Purpose: To investigate whether placement of a polyester-covered stent-graft increases the primary patency of transjugular intrahepatic portosystemic stent shunts (TIPSS). Methods: Between 1995 and 1997 Cragg Endopro or Passager MIBS stent-grafts were used for the creation of TIPSS in eight male patients, 35-59 years of age (mean 48 years). All patients suffered from recurrent variceal bleeding and/or refractory ascites due to liver cirrhosis. Seven stent-grafts were dilated to a diameter of 10 mm, one to 12 mm. Follow-up was performed with duplex ultrasound, clinical assessment, and angiography. Results: The technical success rate for creation of a TIPSS was 100%. The mean portosystemic pressure gradient decreased from 25 mmHg to 12 mmHg. In seven of eight patients TIPSS dysfunction occurred between 2 days and 3 years after stent-graft placement. In one patient the TIPSS is still primarily patent (224 days after creation). The secondary patency rates are 31 days to 3 years. Conclusion: The primary use of polyester-covered stent-grafts for TIPSS did not increase primary patency rates in our small series.

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

    PubMed Central

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

    2015-01-01

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

  17. Thoracic Stent Graft Implantation for Aortic Coarctation with Patent Ductus Arteriosus via Retroperitoneal Iliac Approach in the Presence of Small Sized Femoral Artery

    PubMed Central

    Korkmaz, Ozge; Beton, Osman; Goksel, Sabahattin; Kaya, Hakkı; Berkan, Ocal

    2016-01-01

    Endovascular stent graft implantation is a favorable method for complex aortic coarctation accompanied by patent ductus arteriosus. Herein, an 18-year-old woman with complex aortic coarctation and patent ductus arteriosus was successfully treated by endovascular thoracic stent graft via retroperitoneal approach. The reason for retroperitoneal iliac approach was small sized common femoral arteries which were not suitable for stent graft passage. This case is the first aortic coarctation plus patent ductus arteriosus case described in the literature which is treated by endovascular thoracic stent graft via retroperitoneal approach. PMID:27242935

  18. Chronic vascular response after self-expanding nitinol stent implantation in superficial femoral arteries: a serial intravascular ultrasound analysis.

    PubMed

    Nishimura, Machiko; Fujii, Kenichi; Fukunaga, Masashi; Kawasaki, Daizo; Miki, Kojiro; Saita, Ten; Horimatsu, Tetsuo; Tamaru, Hiroto; Imanaka, Takahiro; Naito, Yoshiro; Masuyama, Tohru

    2016-10-01

    The mechanical properties of the self-expanding nitinol stents (SENS) and chronic biological stimulation on the wall from the SENS have not been fully investigated. This study evaluated the mechanical vascular response to SENS implantation in superficial femoral artery (SFA) lesions using serial volumetric intravascular ultrasound (IVUS). Twenty-five symptomatic patients due to de novo SFA lesions scheduled for SENS placement were prospectively enrolled. Serial IVUS studies were performed immediately after crossing with a guidewire, immediately after the procedure, and at a 8-month follow-up. Serial IVUS volumetric analysis was conducted after stent deployment and at follow-up. Mean stent, lumen and neointimal areas were calculated as the volume divided by the stent length, and the calcium arc was measured. At follow-up, SENS had increased 40.6 % in overall volume. The chronic stent expansion tended to be larger, and the mean neointimal area at the 8-month follow-up was significantly larger in less calcified lesions compared to heavily calcified lesions. As a result, the mean late lumen area loss was significantly larger in lesions with calcium arcs of 0° and in the first and second quadrants than in those with calcium arcs in the third and fourth quadrants (2.8 ± 7.2, 1.3 ± 5.6, 0.6 ± 5.9, 1.2 ± 5.4, -0.8 ± 5.2 mm(2), respectively; p < 0.001). SENSs continued to enlarge with intimal proliferation over 8 months in all lesions. Although arterial calcium affected the degree of chronic stent expansion during the follow-up period, neointimal proliferation was smaller in heavily calcified lesion compared to less calcified lesion following SENS implantation.

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

    PubMed

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

    2015-01-01

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

  20. Longitudinal stent deformation during coronary bifurcation stenting.

    PubMed

    Vijayvergiya, Rajesh; Sharma, Prafull; Gupta, Ankush; Goyal, Praveg; Panda, Prashant

    2016-03-01

    A distortion of implanted coronary stent along its longitudinal axis during coronary intervention is known as longitudinal stent deformation (LSD). LSD is frequently seen with newer drug eluting stents (DES), specifically with PROMUS Element stent. It is usually caused by impact of guide catheter tip, or following passage of catheters like balloon catheter, IVUS catheter, guideliner, etc. We hereby report a case of LSD during coronary bifurcation lesion intervention, using two-stents technique. Patient had acute stent thrombosis as a complication of LSD, which was successfully managed. PMID:26811144

  1. Utility of drug-eluting stents in complex lesions and high-risk patients.

    PubMed

    Nikolsky, Eugenia; Stone, Gregg W

    2007-02-01

    Drug-eluting stents represent a breakthrough technology designed to deliver high concentrations of a bioactive agent locally to an atherosclerotic lesion, thereby minimizing systemic side effects of the drug. The safety and efficacy of drug-eluting stents have clearly been demonstrated in noncomplex lesions. This article presents an evidence-based analysis of the current experience with CYPHER sirolimus-eluting stents (Cordis Corp., Miami Lakes, FL) and TAXUS paclitaxel-eluting stents (Boston Scientific, Natick, MA) in a broad spectrum of high-risk and/or complex subsets of patients and lesions, including those with diabetes mellitus, multivessel disease, diffuse disease, very small vessels, lesions in saphenous vein grafts, chronic total occlusions, in-stent restenosis, ostial and bifurcation lesions, unprotected left main disease, and acute myocardial infarction. Emerging data in several of these subsets suggest that drug-eluting stents are safe and effective, and their use may currently be recommended, whereas in other groups of patients and lesions the efficacy and/or safety of drug-eluting stents remains to be determined, thus warranting caution. It is anticipated that penetration of drug-eluting stents will continue to increase, and fewer patients will require surgical revascularization to achieve sustained event-free survival.

  2. Computational blood flow and vessel wall modeling in a CT-based thoracic aorta after stent-graft implantation

    NASA Astrophysics Data System (ADS)

    Hazer, Dilana; Stoll, Markus; Schmidt, Eduard; Richter, Goetz-M.; Dillmann, Rüdiger

    2010-03-01

    Abnormal blood flow conditions and structural fatigue within stented vessels may lead to undesired failure causing death to the patient. Image-based computational modeling provides a physical and realistic insight into the patientspecific biomechanics and enables accurate predictive simulations of development, growth and failure of cardiovascular diseases as well as associated risks. Controlling the efficiency of an endovascular treatment is necessary for the evaluation of potential complications and predictions on the assessment of the pathological state. In this paper we investigate the effects of stent-graft implantation on the biomechanics in a patient-specific thoracic aortic model. The patient geometry and the implanted stent-graft are obtained from morphological data based on a CT scan performed during a controlling routine. Computational fluid dynamics (CFD) and computational structure mechanics (CSM) simulations are conducted based on the finite volume method (FVM) and on the finite element method (FEM) to compute the hemodynamics and the elastomechanics within the aortic model, respectively. Physiological data based on transient pressure and velocity profiles are used to set the necessary boundary conditions. Further, the effects of various boundary conditions and definition of contact interactions on the numerical stability of the blood flow and the vessel wall simulation results are also investigated. The quantification of the hemodynamics and the elastomechanics post endovascular intervention provides a realistic controlling of the state of the stented vessel and of the efficiency of the therapy. Consequently, computational modeling would help in evaluating individual therapies and optimal treatment strategies in the field of minimally invasive endovascular surgery.

  3. First-generation versus second-generation drug-eluting stents in current clinical practice: updated evidence from a comprehensive meta-analysis of randomised clinical trials comprising 31 379 patients

    PubMed Central

    Navarese, Eliano Pio; Kowalewski, Mariusz; Kandzari, David; Lansky, Alexandra; Górny, Bartosz; Kołtowski, Łukasz; Waksman, Ron; Berti, Sergio; Musumeci, Giuseppe; Limbruno, Ugo; van der Schaaf, Rene J; Kelm, Malte; Kubica, Jacek; Suryapranata, Harry

    2014-01-01

    Background First-generation drug-eluting stents (DES) have become the most widely used devices worldwide for management of coronary artery disease. As remote follow-up data were becoming available, concerns emerged in regard to their long-term safety. Second-generation DES were designed to overcome safety issues, but the results of randomised clinical trials remain conflicting. Methods We compared the safety and efficacy of first-generation versus second-generation Food and Drug Administration approved DES; the following devices were included: first-generation sirolimus-eluting stent (SES) and paclitaxel-eluting stents (PES); second-generation everolimus-eluting stent (EES), zotarolimus-eluting stent Endeavor and ZES-Resolute (ZES-R). Prespecified safety end points comprised ≤1 and >1 year: overall and cardiac mortality, myocardial infarction (MI), definite/definite or probable ST; efficacy end points were target lesion revascularisation and target vessel revascularisation. Composite end points were analysed as well. Results 33 randomised controlled trials involving 31 379 patients with stable coronary artery disease or acute coronary syndrome undergoing DES implantation were retrieved. No differences in mortality among devices were found. In the overall class comparison, second-generation DES were associated with a 22% reduction of odds of MI at short-term OR 0.77 (95% CI 0.68 to 0.89) p=0.0002; EES reduced the odds of definite-probable ST compared with PES: OR 0.33 (95% CI 0.15 to 0.73) p=0.006; First-generation SES along with second-generation EES and ZES-R showed similar efficacy in decreasing the odds of repeat revascularisation. Conclusions Second-generation EES and ZES-R offer similar levels of efficacy compared with first-generation SES, but are more effective than PES; however, only second-generation EES significantly reduced the incidence of MI and ST, and therefore should be perceived as the safest DES to date. PMID:25332803

  4. CYP2C19 loss-of-function alleles are not associated with clinical outcome of clopidogrel therapy in patients treated with newer-generation drug-eluting stents

    PubMed Central

    Choi, Ik Jun; Koh, Yoon-Seok; Park, Mahn-Won; Her, Sung Ho; Choi, Yun-Seok; Park, Chul-Soo; Park, Hun-Jun; Kim, Pum-Joon; Chung, Wook-Sung; Kim, Ho-Sook; Shin, Jae-Gook; Seung, Ki-Bae; Chang, Kiyuk

    2016-01-01

    Abstract CYP2C19 loss-of-function (LOF) alleles adversely affect clinical outcome of clopidogrel therapy. Recent introduction of a newer-generation drug-eluting stent (DES) has significantly reduced the occurrence of stent thrombosis. The aim of this study was to evaluate the impact of CYP2C19 LOF alleles on clinical outcome in patients treated with the newer-generation DES. The effects of CYP2C19 genotypes were evaluated on clinical outcome of clopidogrel therapy in 2062 patients treated with percutaneous coronary intervention using either first-generation DES (sirolimus- and paclitaxel-eluting stent, n = 1349) or newer-generation DES (everolimus- and zotarolimus-eluting stent, n = 713). The primary clinical outcome was major cardiac and cerebrovascular event (MACCE) including cardiac death, nonfatal myocardial infarction, stroke, and stent thrombosis during 1 year of follow-up. CYP2C19 LOF alleles were significantly associated with a higher risk of MACCE in patients treated with first-generation DES (hazard ratio [HR] 2.599, 95% confidence interval [CI] 1.047–6.453; P = 0.034). In contrast, CYP2C19 LOF alleles were not associated with primary outcome in newer-generation DES (HR 0.716, 95% CI 0.316–1.622; P = 0.522). In the further multivariate analysis, CYP2C19 LOF alleles were not associated with MACCE in patients receiving newer-generation DES (adjusted HR 0.540, 95% CI 0.226–1.291; P = 0.166), whereas they were demonstrated to be an independent risk factor for MACCE in those implanted with first-generation DES (adjusted HR 3.501, 95% CI 1.194–10.262; P = 0.022). In contradiction to their clinical impact in first-generation DES era, CYP2C19 LOF alleles may not affect clinical outcome of clopidogrel therapy in patients treated with newer-generation DES. PMID:27368038

  5. The Supralimus sirolimus-eluting stent.

    PubMed

    Lemos, Pedro A; Bienert, Igor

    2013-05-01

    The use of biodegradable polymeric coatings has emerged as a potential bioengineering target to improve the vascular compatibility of coronary drug-eluting stents (DESs). This review summarizes the main features and scientific facts about the Supralimus sirolimus-eluting stent (Sahajanand Medical Technologies Ltd, Surat, India), which is a biodegradable polymer-based, sirolimus-eluting metallic stent that was recently introduced for routine use in Europe. The novel stent is built on a stainless steel platform, coated with a blend of biodegradable polymers (poly-l-lactide, poly-dl-lactide-co-glycolide and polyvinyl pyrrolidone; coating thickness is 4-5 µm). The active agent is the antiproliferative sirolimus in a dose load of 1.4 µg/mm(2), which is released within 48 days. The Supralimus stent was initially evaluated in the single-arm SERIES-I study, which showed binary angiographic restenosis rates of 0% (in-stent) and 1.7% (in-segment) and an in-stent late lumen loss of 0.09 ± 0.28 mm. The multicenter randomized PAINT trial compared two DESs with identical metallic platforms and biodegradable polymer carriers, but different agents (Infinnium [Sahajanand Medical Technologies Pvt Ltd] paclitaxel-eluting stent or Supralimus sirolimus-eluting stent) against bare stents. After 3 years, the pooled DES population had similar rates of cardiac death or myocardial infarction (9 vs 7.1%; p = 0.6), but a lower risk of repeat interventions (10 vs 29.9%; p < 0.01) than controls with bare stents. The incidence of definite or probable stent thrombosis in the pooled DES group was 2.3% (1st year: 1.8%; 2nd year: 0.4% and 3rd year: 0%). These results demonstrate that the novel Supralimus stents are effective in reducing reintervention, while potentially improving the safety profile by decreasing the risk of late-term thrombosis, even though further studies would be necessary to confirm these findings.

  6. The Supralimus sirolimus-eluting stent.

    PubMed

    Lemos, Pedro A; Bienert, Igor

    2013-05-01

    The use of biodegradable polymeric coatings has emerged as a potential bioengineering target to improve the vascular compatibility of coronary drug-eluting stents (DESs). This review summarizes the main features and scientific facts about the Supralimus sirolimus-eluting stent (Sahajanand Medical Technologies Ltd, Surat, India), which is a biodegradable polymer-based, sirolimus-eluting metallic stent that was recently introduced for routine use in Europe. The novel stent is built on a stainless steel platform, coated with a blend of biodegradable polymers (poly-l-lactide, poly-dl-lactide-co-glycolide and polyvinyl pyrrolidone; coating thickness is 4-5 µm). The active agent is the antiproliferative sirolimus in a dose load of 1.4 µg/mm(2), which is released within 48 days. The Supralimus stent was initially evaluated in the single-arm SERIES-I study, which showed binary angiographic restenosis rates of 0% (in-stent) and 1.7% (in-segment) and an in-stent late lumen loss of 0.09 ± 0.28 mm. The multicenter randomized PAINT trial compared two DESs with identical metallic platforms and biodegradable polymer carriers, but different agents (Infinnium [Sahajanand Medical Technologies Pvt Ltd] paclitaxel-eluting stent or Supralimus sirolimus-eluting stent) against bare stents. After 3 years, the pooled DES population had similar rates of cardiac death or myocardial infarction (9 vs 7.1%; p = 0.6), but a lower risk of repeat interventions (10 vs 29.9%; p < 0.01) than controls with bare stents. The incidence of definite or probable stent thrombosis in the pooled DES group was 2.3% (1st year: 1.8%; 2nd year: 0.4% and 3rd year: 0%). These results demonstrate that the novel Supralimus stents are effective in reducing reintervention, while potentially improving the safety profile by decreasing the risk of late-term thrombosis, even though further studies would be necessary to confirm these findings. PMID:23597097

  7. The Tradeoff Between Shorter and Longer Courses of Dual Antiplatelet Therapy After Implantation of Newer Generation Drug-Eluting Stents.

    PubMed

    Bittl, John A

    2016-01-01

    The benefit of prolonged dual antiplatelet therapy (DAPT) after implantation of drug-eluting stents (DESs) remains uncertain. In 10 randomized controlled trials (RCTs) of 31,666 predominantly low-risk patients undergoing DES implantation, shorter courses (3-12 months) of DAPT resulted in lower mortality (odds ratio [OR] 0.83, 95 % confidence interval [CI] 0.69-0.98) and major hemorrhage (OR 0.60, 95 % CI 0.48-0.75) but increased myocardial infarction (MI, OR 1.34, 95 % CI 1.04-1.73) and stent thrombosis (ST, OR 1.75, 95 % CI 1.08-2.82) than did longer courses (12-36 months) of DAPT. A risk-benefit analysis identified 3 fewer deaths and 5 fewer bleeds but 4 more MIs and 3 more STs annually for every 1000 patients treated with the shorter courses. In the predominantly low-risk population enrolled in RCTs, limiting DAPT to 3 to 12 months after DES implantation saved lives and prevented bleeding at the expense of increased ST and MI. PMID:26732901

  8. Clinical Impact of Dual Antiplatelet Therapy Use in Patients Following Everolimus-eluting Stent Implantation: Insights from the SEEDS Study

    PubMed Central

    Zhang, Yao-Jun; Zhao, Ye-Lin; Xu, Bo; Han, Ya-Ling; Li, Bao; Liu, Qiang; Su, Xi; Pang, Si; Lu, Shu-Zheng; Guo, Xiao-Feng; Yang, Yue-Jin

    2015-01-01

    Background: Studies have suggested that use of prolonged dual antiplatelet therapy (DAPT) following new generation drug-eluting stent implantation may increase costs and potential bleeding events. This study aimed to investigate the association of DAPT status with clinical safety in patients undergoing everolimus-eluting stent (EES) implantation in the SEEDS study (A Registry to Evaluate Safety and Effectiveness of Everolimus Drug-eluting Stent for Coronary Revascularization) at 2-year follow-up. Methods: The SEEDS study is a prospective, multicenter study, where patients (n = 1900) with small vessel, long lesion, or multi-vessel diseases underwent EES implantation. Detailed DAPT status was collected at baseline, 6-month, 1- and 2-year. DAPT interruption was defined as any interruption of aspirin and/or clopidogrel more than 14 days. The net adverse clinical events (NACE, a composite endpoint of all-cause death, all myocardial infarction (MI), stroke, definite/probable stent thrombosis (ST), and major bleeding (Bleeding Academic Research Consortium II-V)) were investigated according to the DAPT status at 2-year follow-up. Results: DAPT was used in 97.8% of patients at 6 months, 69.5% at 12 months and 35.4% at 2 years. It was observed that the incidence of NACE was low (8.1%) at 2 years follow-up, especially its components of all-cause death (0.9%), stroke (1.1%), and definite/probable ST (0.7%). DAPT was not an independent predictor of composite endpoint of all-cause death/MI/stroke (hazard ratio [HR]: 0.693, 95% confidence interval [CI]: 0.096–4.980, P = 0.715) and NACE (HR: 1.041, 95% CI: 0.145–7.454, P = 0.968). Of 73 patients who had DAPT interruption, no patient had ST at 12-month, and only 1 patient experienced ST between 1- and 2-year (1.4%). There was a high frequency of major bleeding events (53/65, 82.5%) occurred in patients receiving DAPT treatment. Conclusions: Prolonged DAPT use was not associated with improved clinical safety. The study

  9. Covered Stent Implantation for the Treatment of Direct Carotid-Cavernous Fistula and Its Mid-Term Follow-up

    PubMed Central

    Briganti, F.; Tortora, F.; Marseglia, M.; Napoli, M.; Cirillo, L.

    2009-01-01

    Summary Carotid-cavernous fistulas are abnormal arteriovenous communications either directly between the internal carotid artery and the cavernous sinus or between the dural branches of the internal and external carotid arteries. These fistulas predominantly present with ocular manifestations and they are treated mainly by endovascular techniques in most cases. A detailed review of the literature allowed us to make a complete analysis of the information available on the topic. We describe a case of a direct carotid-cavernous fistula occluded by endovascular implantation of a covered stent, showing the persistence of results after three years. PMID:20465897

  10. Nitinol stent implantation for femoropopliteal disease in patients on hemodialysis: results of the 3-year retrospective multicenter APOLLON study.

    PubMed

    Fujihara, Masahiko; Higashimori, Akihiro; Kato, Yoshihiro; Taniguchi, Hiromasa; Iwasaki, Yusuke; Amano, Tomonori; Sumiyoshi, Akinori; Nishiya, Daisuke; Yokoi, Yoshiaki

    2016-09-01

    The clinical outcomes of nitinol stents for femoropopliteal arterial (FP) disease in patients on hemodialysis were assessed. Endovascular therapy (EVT) is accepted for symptomatic FP disease. However, the clinical outcomes of patients on dialysis are not well known. A multicenter retrospective study was conducted with data between November 2010 and August 2013. A total of 484 consecutive patients who successfully underwent EVT for FP disease with nitinol stents were recruited and analyzed. Patients were categorized into the hemodialysis group (N = 161) and non-hemodialysis group (N = 323). The primary measure was primary patency verified by duplex ultrasound at a rest peak systolic velocity (PSVR) of >2.5, and secondary measures were freedom from target lesion revascularization (TLR) and major amputation-free survival (AFS). Average follow-up duration was 19.5 ± 13.5 months. The primary patency rate at 3 years was significantly lower in the hemodialysis group than the non-hemodialysis group (33.8 vs. 43.7 %; p = 0.036). Freedom from TLR at 3 years was 55.0 % in the hemodialysis group and 66.1 % in the non-hemodialysis group (p = 0.032). The hemodialysis group showed a significantly lower AFS rate at 3 years than the non-hemodialysis group (86.4 vs. 58.2 %; p < 0.001). In hemodialysis patients, nitinol stent use resulted in a lower patency rate, higher TLR rate, and lower AFS rate compared to non-hemodialysis patients. These data suggest that nitinol stent implantation for FP arteries in hemodialysis patient needs to be reconsidered. PMID:26337619

  11. Treatment of a Celiac Trunk Aneurysm Close to the Hepato-splenic Bifurcation by Using Hepatic Stent-graft Implantation and Splenic Artery Embolization

    SciTech Connect

    Basile, Antonio Lupattelli, Tommaso; Magnano, Marco; Giulietti, Giorgio; Privitera, Giambattista; Battaglia, Giuseppe; Monaca, Vincenzo; Ettorre, Giancarlo

    2007-02-15

    We present a case of a 73-year-old man in whom a celiac trunk aneurysm close to the hepato-splenic bifurcation was discovered and treated by using celiac-hepatic stent-grafts implantation and splenic artery embolization.

  12. Prolonged high-pressure balloon angioplasty of femoropopliteal lesions: Impact on stent implantation rate and mid-term outcome

    PubMed Central

    Rigatelli, Gianluca; Palena, Mariano; Cardaioli, Paolo; dell'Avvocata, Fabio; Giordan, Massimo; Vassilev, Dobrin; Manzi, Marco

    2014-01-01

    Objectives To assess the impact on stent implantation rate and mid-term outcomes of prolonged high pressure angioplasty of femoropopliteal lesions. Methods We retrospectively enrolled 620 consecutive patients from January 2011 to December 2011 (75.6 ± 12.3 years, 355 males, 76.5% in Rutherford class 5–6), referred for critical limb ischemia and submitted to prolonged high-pressure angioplasty of femoropopliteal lesions. The definition of prolonged high-pressure angioplasty includes dilation to at least 18 atm for at least 120 s. Procedural data, and clinical and instrumental follow-up were analyzed to assess stent implantation rate and mid-term outcomes. Results The preferred approach was ipsilateral femoral antegrade in 433/620 patients (69.7%) and contralateral cross-over in 164/620 (26.4%) and popliteal retrograde + femoral antegrade in 23/620 (3.7%). Techniques included subintimal angioplasty in 427/620 patients (68.8%) and endoluminal angioplasty in 193/620 patients (31.2%). The prolonged high pressure balloon angioplasty procedure was successful in 86.2% (minor intra-procedural complications rate 15.7 %), stent implantation was performed in 74 patients (11.9%), with a significant improvement of ankle-brachial index (0.29 ± 0.6 vs. 0.88 ± 0.3, P < 00.1) and Rutherford class (5.3 ± 0.8 vs. 0.7 ± 1.9, P < 0.01), a primary patency rate of 86.7%, restenosis of 18.6 % on Doppler ultrasound and a target lesion revascularization of 14.8% at a mean follow-up of 18.1 ± 6.4 months (range 1–24 months). Secondary patency rate was 87.7%. Conclusions Prolonged high pressure angioplasty of femoropopliteal lesions appears to be safe and effective allowing for an acceptable patency and restenosis rates on mid-term. PMID:25009562

  13. Fate of side branches after intracoronary implantation of the Gianturco-Roubin flex-stent for acute or threatened closure after percutaneous transluminal coronary angioplasty.

    PubMed

    Mazur, W; Grinstead, W C; Hakim, A H; Dabaghi, S F; Abukhalil, J M; Ali, N M; Joseph, J; French, B A; Raizner, A E

    1994-12-15

    Side branch occlusion may occur in the course of percutaneous transluminal coronary angioplasty (PTCA), particularly if complicated by site dissection. Concern that the additional placement of a stent may further jeopardize side branches is logical. Consequently, this study analyzed pre-PTCA, post-PTCA, poststent, and 6-month follow-up angiograms of 100 consecutive patients in whom 103 Gianturco-Roubin stents were implanted for acute or threatened closure after PTCA. Side branches were defined as major (> 50% of the stented vessel diameter) and minor (< 50%). Minor branches, often < 1 mm in diameter, were assessed only for patency. One hundred eight major branches, of which 33 were diseased (> 50% stenosis), and 129 minor branches were analyzed. Seven major branches (6%), all of which were diseased before PTCA, and 23 minor branches (18%) were lost after PTCA. Immediately after stent insertion, only 1 additional major and 1 minor branch were lost, whereas 2 of 7 major (29%) and 9 of 23 minor (39%) branches reappeared. At follow-up angiography, 7 major branches (6%) were more stenosed and 6 (6%) were improved compared with the angiogram before PTCA. Only 2 major (2%) and 5 minor (4%) branches remained occluded. Additionally, 2 major and 1 minor branch, which were patent after PTCA and stenting, were occluded at follow-up as a result of total occlusion of the stented segment.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7977091

  14. Mechanisms and Patterns of Intravascular Ultrasound In-Stent Restenosis Among Bare Metal Stents and First- and Second-Generation Drug-Eluting Stents.

    PubMed

    Goto, Kosaku; Zhao, Zhijing; Matsumura, Mitsuaki; Dohi, Tomotaka; Kobayashi, Nobuaki; Kirtane, Ajay J; Rabbani, LeRoy E; Collins, Michael B; Parikh, Manish A; Kodali, Susheel K; Leon, Martin B; Moses, Jeffrey W; Mintz, Gary S; Maehara, Akiko

    2015-11-01

    The most common causes of in-stent restenosis (ISR) are intimal hyperplasia and stent under expansion. The purpose of this study was to use intravascular ultrasound (IVUS) to compare the ISR mechanisms of bare metal stents (BMS), first-generation drug-eluting stents (DES), and second-generation DES. There were 298 ISR lesions including 52 BMS, 73 sirolimus-eluting stents, 52 paclitaxel-eluting stents, 16 zotarolimus-eluting stents, and 105 everolimus-eluting stent. Mean patient age was 66.6 ± 1.1 years, 74.2% were men, and 48.3% had diabetes mellitus. BMS restenosis presented later (70.0 ± 66.7 months) with more intimal hyperplasia compared with DES (BMS 58.6 ± 15.5%, first-generation DES 52.6 ± 20.9%, second-generation DES 48.2 ± 22.2%, p = 0.02). Although reference lumen areas were similar in BMS and first- and second-generation DES, restenotic DES were longer (BMS 21.8 ± 13.5 mm, first-generation DES 29.4 ± 16.1 mm, second-generation DES 32.1 ± 18.7 mm, p = 0.003), and stent areas were smaller (BMS 7.2 ± 2.4 mm(2), first-generation DES 6.1 ± 2.1 mm(2), second-generation DES 5.7 ± 2.0 mm(2), p <0.001). Stent fracture was seen only in DES (first-generation DES 7 [5.0%], second-generation DES 8 [7.4%], p = 0.13). In conclusion, restenotic first- and second-generation DES were characterized by less neointimal hyperplasia, smaller stent areas, longer stent lengths, and more stent fractures than restenotic BMS.

  15. A prospective 3-year follow-up trial of implantation of two trabecular microbypass stents in open-angle glaucoma

    PubMed Central

    Donnenfeld, Eric D; Solomon, Kerry D; Voskanyan, Lilit; Chang, David F; Samuelson, Thomas W; Ahmed, Iqbal Ike K; Katz, L Jay

    2015-01-01

    Purpose To evaluate 3-year safety and intraocular pressure (IOP) following two trabecular microbypass stents in phakic and pseudophakic subjects with open-angle glaucoma (OAG) not controlled on preoperative medication. Patients and methods In this prospective pilot study, phakic or pseudophakic subjects with OAG and IOP between 18 mmHg and 30 mmHg on one preoperative topical ocular hypotensive medication underwent medication washout. Thirty-nine qualified subjects with preoperative unmedicated IOP ≥22 mmHg and ≤38 mmHg received two stents. Postoperative examinations were scheduled at Day 1, Week 1, Months 1, 3, 6, and 12, and semiannually through Month 60. Ocular hypotensive medication was considered if postoperative IOP exceeded 21 mmHg. IOP, medication use, and safety were assessed at each visit. Subject follow-up through Month 36 was completed. Results Thirty-six eyes (92.3%; 95% confidence interval [CI] 79.1%, 98.4%) achieved the primary efficacy end point of Month 12 reduction in IOP ≥20% from baseline (unmedicated IOP) without ocular hypotensive medication. Four subjects required medication during the Month 36 follow-up period. Mean IOP at 36 months for subjects not taking medication was 15.2 mmHg. At 36 months, subjects sustained mean IOP decrease of 9.1±2.7 mmHg (95% CI 8.0 mmHg, 10.14 mmHg), or 37% IOP reduction, from unmedicated baseline IOP. Compared to preoperative medicated IOP, subjects had mean reduction at Month 36 of 5.5±2.7 mmHg (95% CI 4.5 mmHg, 6.6 mmHg), or 26% reduction. Both measures of IOP reduction were highly significant (P<0.001). Other than one case of early postoperative hyphema that resolved at 1 week, no postoperative adverse events were attributed to stent implantation. Conclusion In a pilot study, two trabecular microbypass stents to treat OAG subjects on one preoperative medication provided statistically significant, sustained, and safe reduction of IOP to ≤15 mmHg without medication through 36 months. PMID:26604675

  16. Implantable Cardioverter-Defibrillator Shock after Stenting Across the Device Leads.

    PubMed

    Mehra, Sanjay; Chelu, Mihail Gabriel

    2016-02-01

    A 45-year-old man with nonischemic cardiomyopathy and end-stage renal disease had lived uneventfully with a cardiac resynchronization therapy defibrillator (CRT-D) for 5 years. Less than a month before presenting at our institution, he had undergone stenting of his partially occluded subclavian vein, to relieve stenosis of the ipsilateral arteriovenous fistula that was used for his hemodialysis. The CRT-D subsequently discharged. Device interrogation revealed that electrical noise originating from leads damaged by the stent had caused the inappropriate shock and intermittent electrical discharges thereafter. The patient was highly traumatized by these events and insisted upon device removal, which deprived him of a potentially life-saving intervention. He later had a cardiac arrest that resulted in sustained profound hypoxic ischemic encephalopathy with minimal neurologic recovery: his family placed him in a long-term care facility on ventilator support, with a tracheostomy and feeding tube. This situation might have been avoided through collaboration between the interventional radiologist and the electrophysiologist. To our knowledge, this is the first report of a patient with nonischemic cardiomyopathy and end-stage renal disease who presented with inappropriate defibrillator discharge caused by lead damage secondary to stenting across the leads. PMID:27047295

  17. Implantable Cardioverter-Defibrillator Shock after Stenting Across the Device Leads

    PubMed Central

    Chelu, Mihail Gabriel

    2016-01-01

    A 45-year-old man with nonischemic cardiomyopathy and end-stage renal disease had lived uneventfully with a cardiac resynchronization therapy defibrillator (CRT-D) for 5 years. Less than a month before presenting at our institution, he had undergone stenting of his partially occluded subclavian vein, to relieve stenosis of the ipsilateral arteriovenous fistula that was used for his hemodialysis. The CRT-D subsequently discharged. Device interrogation revealed that electrical noise originating from leads damaged by the stent had caused the inappropriate shock and intermittent electrical discharges thereafter. The patient was highly traumatized by these events and insisted upon device removal, which deprived him of a potentially life-saving intervention. He later had a cardiac arrest that resulted in sustained profound hypoxic ischemic encephalopathy with minimal neurologic recovery: his family placed him in a long-term care facility on ventilator support, with a tracheostomy and feeding tube. This situation might have been avoided through collaboration between the interventional radiologist and the electrophysiologist. To our knowledge, this is the first report of a patient with nonischemic cardiomyopathy and end-stage renal disease who presented with inappropriate defibrillator discharge caused by lead damage secondary to stenting across the leads. PMID:27047295

  18. Local hemodynamic changes caused by main branch stent implantation and subsequent virtual side branch balloon angioplasty in a representative coronary bifurcation.

    PubMed

    Williams, Andrew R; Koo, Bon-Kwon; Gundert, Timothy J; Fitzgerald, Peter J; LaDisa, John F

    2010-08-01

    Abnormal blood flow patterns promoting inflammation, cellular proliferation, and thrombosis may be established by local changes in vessel geometry after stent implantation in bifurcation lesions. Our objective was to quantify altered hemodynamics due to main vessel (MV) stenting and subsequent virtual side branch (SB) angioplasty in a coronary bifurcation by using computational fluid dynamics (CFD) analysis. CFD models were generated from representative vascular dimensions and intravascular ultrasound images. Time-averaged wall shear stress (TAWSS), oscillatory shear index (OSI), and fractional flow reserve (FFR) were quantified. None of the luminal surface was exposed to low TAWSS (<4 dyn/cm(2)) in the nondiseased bifurcation model. MV stenting introduced eccentric areas of low TAWSS along the lateral wall of the MV. Virtual SB angioplasty resulted in a more concentric region of low TAWSS in the MV distal to the carina and along the lateral wall of the SB. The luminal surface exposed to low TAWSS was similar before and after virtual SB angioplasty (rest: 43% vs. 41%; hyperemia: 18% vs. 21%) and primarily due to stent-induced flow alterations. Sites of elevated OSI (>0.1) were minimal but more impacted by general vessel geometry established after MV stenting. FFR measured at a jailed SB was within the normal range despite angiographic stenosis of 54%. These findings indicate that the most commonly used percutaneous interventional strategy for a bifurcation lesion causes abnormal local hemodynamic conditions. These results may partially explain the high clinical event rates in bifurcation lesions.

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

    PubMed

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

    2013-04-01

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

  20. Non-polymeric coatings to control drug release from metallic coronary stents

    NASA Astrophysics Data System (ADS)

    Gupta, Celia Edith Macias

    Percutaneous transluminal coronary angiography (PTCA) is a procedure used to re-open narrowed coronary arteries. During PTCA, a coronary stent is expanded inside a diseased vessel and serves as a scaffold to keep the artery open. The major drawback of stenting is restenosis---a re-narrowing of the vessel resulting from the hyperproliferation of smooth muscle cells. Drug eluting stents (DES) reduce the rate of restenosis compared to bare metal stents. Paclitaxel (PAT) is commonly used in DES for its ability to prevent restenosis. However, DES have been associated with thrombosis due to the polymer carrier that controls drug delivery. Therefore, there is a need to change the drug delivery mechanisms to eliminate the need of polymers. The goal of this dissertation is to develop a novel polymer-free drug eluting stent that controls drug release using nanoscale metal coatings. The coating was designed to release PAT as the metal slowly degrades in biological conditions. Once all the Paclitaxel has eluted from the surface, the coating will continue to degrade until the final result is a bare metal stent. The results of this study include a novel non-polymeric drug delivery system using nanoscale coatings that release Paclitaxel at a rate similar to commercial stents, as well as the biocompatibility and efficacy of these coatings. The non-polymeric drug delivery system described here achieved a Paclitaxel release profile equivalent to clinically available Paclitaxel-eluting stents and effectively inhibits smooth muscle cell proliferation, thereby completely eliminating the need for polymers to control drug release from coronary stents.

  1. Aspiration Thrombectomy and Drug-Eluting Stent Implantation Decrease the Occurrence of Angina Pectoris One Year After Acute Myocardial Infarction

    PubMed Central

    Lee, Wei-Chieh; Fang, Chih-Yuan; Chen, Huang-Chung; Hsueh, Shu-Kai; Chen, Chien-Jen; Yang, Cheng-Hsu; Yip, Hon-Kan; Hang, Chi-Ling; Wu, Chiung-Jen; Fang, Hsiu-Yu

    2016-01-01

    Abstract Angina pectoris is a treatable symptom that is associated with mortality and decreased quality of life. Angina eradication is a primary care goal of care after an acute myocardial infarction (AMI). Our aim was to evaluate factors influencing angina pectoris 1 year after an AMI. From January 2005 to December 2013, 1547 patient received primary percutaneous intervention in our hospital for an acute ST-segment elevation myocardial infarction (MI). Of these patients, 1336 patients did not experience post-MI angina during a 1-year follow-up, and 211 patients did. Univariate and multivariate logistic regression analyses were performed to identify the factors influencing angina pectoris 1 year after an AMI. Propensity score matched analyses were performed for subgroups analyses. The average age of the patients was 61.08 ± 12.77 years, with a range of 25 to 97 years, and 82.9% of the patients were male. During 1-year follow-up, 13.6% of the patients experienced post-MI angina. There was a longer chest pain-to-reperfusion time in the post-MI angina group (P = 0.01), as well as a higher fasting sugar level, glycohemoglobin (HbA1C), serum creatinine, troponin-I and creatine kinase MB (CK-MB). The post-MI angina group also had a higher prevalence of multiple-vessel disease. Manual thrombectomy, and distal protective device and intracoronary glycoprotein IIb/IIIa inhibitor injection were used frequently in the no post-MI angina group. Antiplatelet agents and post-MI medication usage were similar between the 2 groups. Multivariate logistic regression analyses demonstrated that prior MI was a positive independent predictor of occurrence of post-MI angina. Manual thrombectomy use and drug-eluting stent implantation were negative independent predictors of post-MI angina. Higher troponin-I and longer chest pain-to-reperfusion time exhibited a trend toward predicting post-MI angina. Prior MIs were strong, independent predictors of post-MI angina. Manual thrombectomy

  2. Aspiration Thrombectomy and Drug-Eluting Stent Implantation Decrease the Occurrence of Angina Pectoris One Year After Acute Myocardial Infarction.

    PubMed

    Lee, Wei-Chieh; Fang, Chih-Yuan; Chen, Huang-Chung; Hsueh, Shu-Kai; Chen, Chien-Jen; Yang, Cheng-Hsu; Yip, Hon-Kan; Hang, Chi-Ling; Wu, Chiung-Jen; Fang, Hsiu-Yu

    2016-04-01

    Angina pectoris is a treatable symptom that is associated with mortality and decreased quality of life. Angina eradication is a primary care goal of care after an acute myocardial infarction (AMI). Our aim was to evaluate factors influencing angina pectoris 1 year after an AMI.From January 2005 to December 2013, 1547 patient received primary percutaneous intervention in our hospital for an acute ST-segment elevation myocardial infarction (MI). Of these patients, 1336 patients did not experience post-MI angina during a 1-year follow-up, and 211 patients did. Univariate and multivariate logistic regression analyses were performed to identify the factors influencing angina pectoris 1 year after an AMI. Propensity score matched analyses were performed for subgroups analyses.The average age of the patients was 61.08 ± 12.77 years, with a range of 25 to 97 years, and 82.9% of the patients were male. During 1-year follow-up, 13.6% of the patients experienced post-MI angina. There was a longer chest pain-to-reperfusion time in the post-MI angina group (P = 0.01), as well as a higher fasting sugar level, glycohemoglobin (HbA1C), serum creatinine, troponin-I and creatine kinase MB (CK-MB). The post-MI angina group also had a higher prevalence of multiple-vessel disease. Manual thrombectomy, and distal protective device and intracoronary glycoprotein IIb/IIIa inhibitor injection were used frequently in the no post-MI angina group. Antiplatelet agents and post-MI medication usage were similar between the 2 groups. Multivariate logistic regression analyses demonstrated that prior MI was a positive independent predictor of occurrence of post-MI angina. Manual thrombectomy use and drug-eluting stent implantation were negative independent predictors of post-MI angina. Higher troponin-I and longer chest pain-to-reperfusion time exhibited a trend toward predicting post-MI angina.Prior MIs were strong, independent predictors of post-MI angina. Manual thrombectomy and drug

  3. 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.

  4. Failing left ventricle to ascending aorta conduit-Hybrid implantation of a melody valve and NuMed covered stent.

    PubMed

    Gössl, Mario; Johnson, Jonathan N; Hagler, Donald J

    2014-04-01

    We present the case of a 36-year-old woman with increasing shortness of breath, a new 3/4 diastolic murmur, and a complex history of LV outflow tract obstruction. She has undergone multiple surgeries including the replacement of her old LV apex to ascending aorta conduit with a 20-mm Gore-Tex tube graft, addition of a 24-mm homograft sutured between the conduit and the LV apex, and insertion of a 21-mm Freestyle porcine valve conduit between the Gore-Tex tube graft and allograft at age 23. The current assessment showed a failing Freestyle conduit prosthesis leading to left heart decompensation. Due to substantial surgical risk, the patient underwent successful implantation of a Melody valve into the Gore-Tex tube and exclusion of the failing Freestyle bioprosthesis with a NuMed CP stent in a hybrid procedure. The case nicely illustrates the collaborative potential of cardiovascular surgeons and interventional cardiologists in the new arena of a hybrid operating room. Complex hybrid procedures like the current one, especially those including percutaneous placements of valves, offer therapeutic options for patients that are otherwise too high risk for conventional open heart surgery. PMID:23784974

  5. Short-Term Intraocular Pressure Elevations after Combined Phacoemulsification and Implantation of Two Trabecular Micro-Bypass Stents: Prednisolone versus Loteprednol

    PubMed Central

    Wang, Qianqian; Harasymowycz, Paul

    2015-01-01

    Objective. To compare the effects of prednisolone and of loteprednol after combined phacoemulsification and trabecular micro-bypass stent implantation (phaco-iStent). Methods. Patients who underwent phaco-iStent between April 2013 and November 2014 were identified by retrospective chart review. Postoperatively, they received either prednisolone (n = 38) or loteprednol (n = 58). Baseline data was compared. Primary outcomes including intraocular pressure (IOP) and number of glaucoma medications (NGM) were analyzed at preoperative visit, postoperative day 1, weeks 1-2, weeks 3-4, and months 2-3. Results. Both groups had similar preoperative parameters (p > 0.05). The mean IOP spike occurred at postoperative weeks 1-2 with an increase of 2.21 ± 7.30 mmHg in the loteprednol group and 2.54 ± 9.28 mmHg in the prednisolone group. It decreased by weeks 3-4 in both groups and continued to improve at months 2-3. NGM showed significant reduction (p < 0.0001) after the surgery and remained stable in both groups. No significant group effect or time-group interaction in IOP and NGM evolution was detected (p > 0.05). The proportions of patients needing paracentesis were similar between the two groups. Conclusion. Similar early IOP elevations after combined phaco-iStent occurred with both prednisolone and loteprednol. Facilitated glucocorticoid infusion, altered aqueous humor outflow, and local inflammation may be contributing factors. PMID:26266045

  6. Stent Implantation for Malignant Pulmonary Artery Stenosis in a Metastasizing Non-Small Cell Bronchial Carcinoma

    SciTech Connect

    Gutzeit, A.; Koch, S.; Meier, U. R.; Zollikofer, Ch.

    2008-07-15

    A 58-year-old patient with recently diagnosed non-small cell bronchial carcinoma was referred to us with increasing shortness of breath and orthopnea by her family practitioner. To exclude the possibility of a pulmonary embolism, contrast medium-enhanced angio-CT of the thorax was performed. This showed a large mediastinal tumor, which, on the one hand, infiltrated and occluded the left upper lobe bronchus and, on the other, constricted the left pulmonary artery over a considerable part of its length. In view of the palliative situation and massively increasing dyspnea, balloon dilatation of the obstructed left pulmonary artery followed by stent placement was performed. This resulted in an immediate improvement of the symptoms. The originally strongly oxygen-dependent and heavily dyspneic patient could be relieved of the external supply of oxygen and was able to sleep normally without additional medication within 24 h. The patient was able ambulate freely within 2 days, with a markedly improved quality of life.

  7. Hemodynamic impact of abdominal aortic aneurysm stent-graft implantation-induced stenosis.

    PubMed

    Aristokleous, Nicolas; Kontopodis, Nikolaos G; Tzirakis, Konstantinos; Ioannou, Christos V; Papaharilaou, Yannis

    2016-10-01

    The current study aims to computationally evaluate the hemodynamic impact of a novel sealing mechanism employed by a recently developed endograft (Ovation TriVascular Stent-Graft System) for endovascular aneurysm repair. The exploitation of two inflatable O-rings to achieve sealing may be advantageous in terms of accommodating challenging anatomies, but comes at a price of a marked inflow stenosis. Here, four representative patient cases of inflow stenosis ranging from 30 to 80 % were analyzed. Lumen surface models were constructed from 1 month post-operative computed tomography images and then used to numerically compute the complex endograft flow field. Our results highlight coexistence of stenotic wall regions exposed to high shear rate and post-stenotic recirculation zones. These conditions may implicate platelet activation and predispose thrombus formation and thromboembolic complications. A clinically insignificant cycle-averaged pressure drop along the inflow stenosis and further in the endograft main body legs was predicted (range 0.01-1.72 mmHg) which was, however, notable at peak systole (range 3.52-19.73 mmHg). Although the functional impact of the endograft stenosis at rest flow conditions may appear insignificant, increased flow rate during exercise is expected to strongly accentuate the observed effects. Pressure drop in the endograft legs was attributed to suboptimal, based on Murray's scaling law, cross-sectional area ratio between trunk and legs of the device. PMID:26676685

  8. Intractable intraoperative bleeding requiring platelet transfusion during emergent cholecystectomy in a patient with dual antiplatelet therapy after drug-eluting coronary stent implantation (with video)

    PubMed Central

    Fujikawa, Takahisa; Noda, Tomohiro; Tada, Seiichiro; Tanaka, Akira

    2013-01-01

    We report a case of a 76-year-old man, receiving dual antiplatelet therapy (DAPT) with aspirin and ticlopidine for the past 6 years after implantation of drug-eluting coronary stent, developed a severe hypochondriac pain. After diagnosing severe acute cholecystitis by an enhanced CT, emergent laparotomy under continuation of DAPT was attempted. During the operation, intractable bleeding from the adhesiolysed liver surface was encountered, which required platelet transfusion. Subtotal cholecystectomy with abdominal drainage was performed, and the patient recovered without any postoperative bleeding or thromboembolic complications. Like the present case, the final decision should be made to perform platelet transfusion when life-threatening DAPT-induced intraoperative bleeding occurs during an emergent surgery, despite the elevated risk of stent thrombosis. PMID:23536626

  9. Successful treatment of bleeding large duodenal gastrointestinal stromal tumour in a patient under dual antiplatelet therapy after recent drug-eluting coronary stent implantation

    PubMed Central

    Fukuyama, Keita; Fujikawa, Takahisa; Kuramitsu, Shoichi; Tanaka, Akira

    2014-01-01

    We report a case of a 69-year-old man who started dual antiplatelet therapy (APT) with aspirin and clopidogrel after recent implantation of drug-eluting coronary stent and developed massive bleeding due to large duodenal gastrointestinal stromal tumour (GIST). Following endoscopic haemostasis and discontinuation of dual APT, neoadjuvant chemotherapy with imatinib was started under continuation of ‘single’ APT with aspirin. A good chemotherapeutic response was achieved without recurrence of bleeding, and subsequent less invasive surgical resection of the tumour was performed, while preoperative single APT was continued for prevention of stent thrombosis. The patient recovered well without any thromboembolic or bleeding events. Neoadjuvant imatinib therapy and subsequent less invasive surgery under continuation of APT is one of the preferred approaches for patients with duodenal GIST with severe thromboembolic comorbidities, as in the current case. PMID:24777088

  10. Intraluminal tracheal stent fracture in a Yorkshire terrier.

    PubMed

    Woo, Heung-Myong; Kim, Mi-Jeong; Lee, Seung-Gon; Nam, Hyun-Sook; Kwak, Ho-Hyun; Lee, Joon-Seok; Park, In-Chul; Hyun, Changbaig

    2007-10-01

    An 8-year-old Yorkshire terrier was presented with tracheal collapse. Two intraluminal nitinol stents were implanted. The implanted stents were found to be fractured 4 weeks after implantation. The fractured stents were removed. To restore the collapsed trachea, ring prostheses were applied. However, the dog was euthanized because of a bad outcome following surgery.

  11. Stent-grafts for the treatment of TIPS dysfunction: Fluency stent vs Wallgraft stent

    PubMed Central

    Luo, Xue-Feng; Nie, Ling; Wang, Zhu; Tsauo, Jiaywei; Liu, Ling-Jun; Yu, Yang; Zhou, Biao; Tang, Cheng-Wei; Li, Xiao

    2013-01-01

    AIM: To evaluate the clinical efficacy of an expanded polytetrafluoro-ethylene-covered Fluency stent compared with that of a polyethylene terephthalate-covered Wallgraft stent for the management of transjugular intrahepatic portosystemic shunt (TIPS) dysfunction. METHODS: A retrospective review of patients who underwent TIPS revision with stent-grafts between May 2007 and June 2011 was conducted. The patients were divided into two groups according to the stent-grafts implanted: the Fluency stent (Bard Incorporated, Karlsruhe, Germany) and the Wallgraft stent (Boston Scientific, Galway, Ireland). The primary patency rates were calculated and compared using the Kaplan-Meier method. RESULTS: A total of 73 patients were evaluated in this study: 33 with Fluency stents and 40 with Wallgraft stents. The primary patency rates at 12 and 24 mo were 91% and 85%, respectively, in the Fluency stent group and 78% and 63%, respectively, in the Wallgraft stent group. The primary shunt patency rates after TIPS revision were significantly better with the Fluency stent than with the Wallgraft stent (P = 0.033). CONCLUSION: TIPS revision with the Fluency stent has higher medium-term patency rates than that with the Wallgraft stent. PMID:23946607

  12. Endovascular implantation of covered stents in the extracranial carotid and vertebral arteries: Case series and review of the literature

    PubMed Central

    Alaraj, Ali; Wallace, Adam; Amin-Hanjani, Sepideh; Charbel, Fady T; Aletich, Victor

    2011-01-01

    Background: Covered stents are used endovascularly to seal arterial wall defects while preserving vessel patency. This report describes our experience with the use of covered stents to treat cervical pathology, and a review of the literature in regards to this topic is presented. Case Description: Two patients presenting with the carotid blowout syndrome and one patient with a vertebrojugular fistula were treated with covered stents. This allowed for preservation of the vessel and was a treatment alternative to cerebral bypass. Conclusion: Covered stents provide a viable means of preserving the cervical vessels in selected patients; however, long-term follow-up is necessary to determine stent patency and permanency of hemostasis. PMID:21697983

  13. Automatic three-dimensional registration of intra-vascular optical coherence tomography images for the clinical evaluation of stent implantation over time

    NASA Astrophysics Data System (ADS)

    Ughi, Giovanni J.; Adriaenssens, Tom; Larsson, Matilda; Dubois, Christophe; Sinnaeve, Peter; Coosemans, Mark; Desmet, Walter; D'hooghe, Jan

    2012-01-01

    In the last decade a large number of new intracoronary devices (i.e. drug-eluting stents, DES) have been developed to reduce the risks related to bare metal stent (BMS) implantation. The use of this new generation of DES has been shown to substantially reduce, compared with BMS, the occurrence of restenosis and recurrent ischemia that would necessitate a second revascularization procedure. Nevertheless, safety issues on the use of DES persist and full understanding of mechanisms of adverse clinical events is still a matter of concern and debate. Intravascular Optical Coherence Tomography (IV-OCT) is an imaging technique able to visualize the microstructure of blood vessels with an axial resolution <20 μm. Due to its very high spatial resolution, it enables detailed in-vivo assessment of implanted devices and vessel wall. Currently, the aim of several major clinical trials is to observe and quantify the vessel response to DES implantation over time. However, image analysis is currently performed manually and corresponding images, belonging to different IV-OCT acquisitions, can only be matched through a very labor intensive and subjective procedure. The aim of this study is to develop and validate a new methodology for the automatic registration of IV-OCT datasets on an image level. Hereto, we propose a landmark based rigid registration method exploiting the metallic stent framework as a feature. Such a tool would provide a better understanding of the behavior of different intracoronary devices in-vivo, giving unique insights about vessel pathophysiology and performance of new generation of intracoronary devices and different drugs.

  14. Spontaneous Sealing of a Type Ia Endoleak after Ovation Stent Graft Implantation in a Patient with On-Label Aortic Neck Anatomy.

    PubMed

    Pranteda, Chiara; Sirignano, Pasqualino; Capoccia, Laura; Mansour, Wassim; Montelione, Nunzio; Speziale, Francesco

    2016-07-01

    We report a case of an early type Ia endoleak after endovascular aneurysm repair (EVAR) of an abdominal aortic aneurysm by Ovation Stent Graft implantation and spontaneously resolved without further reintervention. The patient presents a conical aortic neck, but EVAR was performed within the instruction for use proposed by manufactory. At completion angiography, a low-flow type Ia endoleak was present and left untreated. Computed tomographic angiography performed on the third postoperative day showed infolding of the 2 sealing rings. The patient was dismissed without further treatment. At 3-month follow-up, the leak appeared spontaneously sealed with partial expansion of the 2 rings.

  15. Plasma pentraxin 3 may be a more sensitive marker of inflammatory response than high-sensitivity C-reactive protein after bare-metal stent compared to drug-eluting stent implantation.

    PubMed

    Hudzik, Bartosz; Szkodzinski, Janusz; Pietka-Rzycka, Anna; Danikiewicz, Aleksander; Wojnar, Rafal; Lekston, Andrzej; Polonski, Lech; Zubelewicz-Szkodzinska, Barbara

    2013-05-01

    C-reactive protein (CRP) and pentraxin 3 (PTX3) are members of a highly conserved pentraxin superfamily. CRP is synthesized in the liver and may represent a systemic response to local inflammation. PTX3 is synthesized locally at the inflammatory sites and may represent a marker for local inflammation at sites of vessel injury. We compared plasma high-sensitivity CRP (hsCRP) and PTX3 concentrations after bare-metal stent (BMS) and drug-eluting stent (DES) implantation. Fifty-three patients with stable coronary artery disease who underwent percutaneous coronary intervention were divided into 2 groups: 1-24 patients (BMS group) and 2-29 patients (DES group). Patients were scheduled for an elective, 6-month clinical follow-up. Major adverse cardiovascular events (MACEs) (death, myocardial infarction, target vessel revascularization) were assessed. Baseline clinical characteristics were similar in both groups. Patients after BMS implantation had a higher median PTX3 concentration 1.02 ng/mL compared to patients after DES implantation 0.80 ng/mL, P=0.045. Median hsCRP concentrations were similar in both groups: 0.9 mg/L versus 0.89 mg/L, respectively. Six-month follow-up was available in 33 patients. Four out of 33 patients had MACEs during follow-up. The cut-off value to predict MACEs for PTX3 was >1.16 ng/mL (P=0.004) and for hsCRP was >0.95 mg/L (P<0.001). Patients after DES implantation showed significantly lower plasma PTX3 levels compared with patients after BMS implantation. hsCRP showed no difference between the study groups. PTX3 may be a more sensitive marker of local inflammatory response due to vessel injury by BMS than hsCRP. DES implantation may attenuate the early inflammatory response. Lower PTX3 levels may reflect potent anti-inflammatory properties of DES.

  16. Implantation of self-expanding metal stent in the treatment of severe bleeding from esophageal ulcer after endoscopic band ligation.

    PubMed

    Mishin, I; Ghidirim, G; Dolghii, A; Bunic, G; Zastavnitsky, G

    2010-09-01

    Endoscopic variceal ligation is superior to sclerotherapy because of its lower rebleeding and complication rates. However, ligation may be associated with life-threatening bleeding from postbanding esophageal ulcer. We report a case of a 49-year-old male with massive hemorrhage from esophageal ulcer on 8th day after successful band ligation of bleeding esophageal varices caused by postviral liver cirrhosis (Child-Pugh class C). A removable polyurethane membrane-covered self-expanding metal stent (SX-ELLA stent Danis, 135 mm × 25 mm, ELLA-CS, Hradec-Kralove, Czech Republic) was inserted in ICU for preventing fatal hemorrhage. Complete hemostasis was achieved and stent was removed after 8 days without rebleeding or any complications. To the best of our knowledge, this is the first report in English literature regarding life-threatening hemorrhage from postbanding esophageal ulcer successfully treated by self-expanding metal stent in a patient with portal hypertension.

  17. Meta-analysis of randomized controlled trials on efficacy and safety of extended thienopyridine therapy after drug-eluting stent implantation

    PubMed Central

    Tang, Wenyi; Yeh, James; Chen, Jian; Liu, Mao; Ke, Jianting; Tan, Guangyi; Lin, Xiufang

    2016-01-01

    Background The potential benefits and risks of extended thienopyridine therapy beyond 12 months after drug-eluting stent (DES) implantation remain unclear. Methods Randomized controlled trials (RCTs) were searched in PubMed, EMBASE, the Cochrane Library and China National Knowledge Infrastructure databases. The adverse clinical endpoints were compared between 12 months group (aspirin alone) and >12 months group (additional thienopyridine plus aspirin after 12-month dual antiplatelet therapy). Odds ratios (ORs) with 95% confidence intervals (95% CIs) were used as summary statistics. A random-effect model was used in the meta-analysis process. Results Finally, three RCTs incorporating 16,265 participants were included in this meta-analysis. The results indicated that the incidences of myocardial infarction (1.55% vs. 2.90%; OR =0.58; 95% CI, 0.40–0.84; P=0.004) and stent thrombosis (0.32% vs. 0.98%; OR =0.35; 95% CI, 0.20–0.62; P<0.001) in the >12 months group were significantly lower than the 12 months group. However, compared to the 12 months group, the extended thienopyridine therapy markedly increased the risk of bleeding events (2.09% vs. 1.28%; OR =1.64; 95% CI, 1.23–2.17; P<0.001). The risks of stroke (0.78% vs. 0.84%; P=0.67) and cardiac death (0.94% vs. 0.89%; P=0.61) were similar between the two groups. Conclusions The synthesis of available evidence indicates that a regimen of extended thienopyridine therapy beyond 12 months may significantly reduce the risks of myocardial infarction and stent thrombosis but increase the risk of bleeding events in the patients who have received DESs implantation. PMID:27747163

  18. Broken Esophageal Stent Successfully Treated by Interventional Radiology Technique

    SciTech Connect

    Zelenak, Kamil; Mistuna, Dusan; Lucan, Jaroslav; Polacek, Hubert

    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.

  19. Low-dose sirolimus-eluting hydroxyapatite coating on stents does not increase platelet activation and adhesion ex vivo.

    PubMed

    Alviar, Carlos L; Tellez, Armando; Wang, Michael; Potts, Pamela; Smith, Doug; Tsui, Manus; Budzynski, Wladyslaw; Raizner, Albert E; Kleiman, Neal S; Lev, Eli I; Granada, Juan F; Kaluza, Greg L

    2012-07-01

    We previously found paclitaxel-eluting polymer-coated stents causing more human platelet-monocyte complex formation than bare metal stents in vitro. Presently, we examined patterns of platelet activation and adhesion after exposure to 6 nanofilm HAp-coated (HAp-nano) stents, 6 HAp-microporous-coated (HAp-micro) stents, 5 HAp sirolimus-eluting microporous-coated (HAp-SES) stents and 5 cobalt-chromium stents (BMS) deployed in an in vitro flow system. Blood obtained from healthy volunteers was circulated and sampled at 0, 10, 30 and 60 min. By flow cytometry, there were no significant differences in P-Selectin expression between the 4 stent types (HAp-nano = 32.5%; HAp-micro = 42.5%, HAp-SES = 10.23%, BMS = 7% change from baseline at 60 min, p = NS); PAC-1 antibody binding (HAp-nano = 11.8%; HAp-micro = 2.9%, HAp-SES = 18%, BMS = 6.4% change from baseline at 60 min, p = NS) or PMC formation (HAp-nano = 21.6%; HAp-micro = 4%, HAp-SES = 6.6%, BMS = 17.4% change from baseline at 60 min, p = NS). The 4 stent types did not differ in the average number of platelet clusters >10 μm in diameter by SEM (HAp-nano = 2.39 ± 5.75; HAp-micro = 2.26 ± 3.43; HAp-SES = 1.93 ± 3.24; BMS = 1.94 ± 2.41, p = NS). The majority of the struts in each stent group were only mildly covered by platelets, (HAp-nano = 80%, HAp-micro = 61%, HAp-SES = 78% and BMS = 52.1%, p = NS). The HAp-microporous-coated stents (ECD) attracted slightly more proteinaceous material than bare metal stents (HAp-micro = 35% struts with complete protein coverage, P < 0.0001 vs. other 3 stent types). In conclusion, biomimetic stent coating with nanofilm or microporous hydroxyapatite, even when eluting low-dose sirolimus, does not increase the platelet activation in circulating human blood, or platelet adhesion to stent surface when compared to bare metal stents in vitro.

  20. Rotational Atherectomy of Three Overlapping Stent Layers.

    PubMed

    Frisoli, Tiberio M; Friedman, Harold; O'Neill, William W

    2016-09-01

    A patient was referred to us for Canadian Cardiovascular Society class III refractory angina. He was found to have in-stent restenosis within three layers of underexpanded stents implanted in 2004, 2011, and 2014. Rotational atherectomy safely yielded stent strut ablation (reduced to one layer), lesion expansion, and very good angiographic and physiologic results. PMID:27591692

  1. Prognostic Impact of 9-Month High-Sensitivity C-Reactive Protein Levels on Long-Term Clinical Outcomes and In-Stent Restenosis in Patients at 9 Months after Drug-Eluting Stent Implantation

    PubMed Central

    Hsieh, I-Chang; Chen, Chun-Chi; Hsieh, Ming-Jer; Yang, Chia-Hung; Chen, Dong-Yi; Chang, Shang-Hung; Wang, Chao-Yung; Lee, Cheng-Hung; Tsai, Ming-Lung

    2015-01-01

    Introduction The level of 9-month high-sensitivity C-reactive protein (hsCRP) in predicting cardiovascular outcomes is scanty in patients at 9 months after receiving drug-eluting stent (DES) implantations. This study aims to evaluate the relationship between 9-month follow-up hsCRP levels and long-term clinical outcomes in patients at 9 months after receiving DES. Methods A total of 1,763 patients who received 9-month follow-up angiography were enrolled and grouped according to hsCRP level 9 months after the DES implantation: group I (718 patients, hsCRP<1.0 mg/L), group II (639 patients, 1.0≦hsCRP≦3.0 mg/L), and group III (406 patients, hsCRP>3.0 mg/L). Results Group III patients had a lower cardiovascular event-free survival rate than group I or II patients during a follow-up of 64±45 months (64.5% vs. 71.6% vs. 72.8%, respectively, p = 0.012). Multivariate analysis showed that a follow-up hsCRP level <3.0 mg/L was an independent predictor of a major adverse cardiovascular event (cardiac death, reinfarction, target lesion revascularization, stenting in a new lesion, or coronary bypass surgery). Group III patients had a higher restenosis rate (11.3% vs. 5.8% vs. 6.6%, respectively, p = 0.002) and loss index (0.21±0.32 vs. 0.16±0.24 vs. 0.18±0.28, respectively, p = 0.001) than group I or II patients in 9-month follow-up angiography. Conclusions A high 9-month follow-up hsCRP level is an independent predictor of long-term clinical cardiovascular outcomes in patients at 9 months after DES implantation. It is also associated with a higher restenosis rate, larger late loss and loss index at 9 months after DES implantation. PMID:26406989

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

    PubMed

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

    2014-07-01

    We assessed the frequency and severity of changes in stent configuration and location after the treatment of intracranial aneurysms, and patterns of in-stent stenosis. We retrospectively reviewed data for consecutive aneurysm patients managed with endovascular implantation of flow-diverter stents (Silk Flow Diverter [Balt Extrusion, Montmorency, France] and Pipeline Embolization Device [ev3/Coviden, Minneapolis, MN, USA]) from October 2011 to July 2012. Routine 2, 6, 9-12, and 16-20 month follow-up angiograms were compared, with a focus on changes in stent configuration and location from immediately after deployment to angiographic follow-up, and the incidence and development of in-stent stenosis. Thirty-four patients with 42 aneurysms met inclusion criteria. The Silk device was implanted in 16 patients (47%, single device in 15), the Pipeline device in 18 (53%, single device in 16). On first follow-up angiography, in-stent stenosis was observed in 38% of Silk devices and 39% of Pipeline devices. In-stent stenosis was asymptomatic in 12 of 13 patients. One woman presented with transient ischemic attacks and required stent angioplasty due to end tapering and mild, diffuse in-stent stenosis. Configuration and location changes, including stent creeping and end tapering were seen in 2/16 patients (13%) with Silk devices, and 0/18 patients with Pipeline devices. We describe stent creeping and end tapering as unusual findings with the potential for delayed clinical complications. In-stent stenosis, with a unique behavior, is a frequent angiographic finding observed after flow-diverter stent implant. The stenosis is usually asymptomatic; however, close clinical and angiographic monitoring is mandatory for individualized management. PMID:24524952

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

    PubMed

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

    2014-07-01

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

  4. The management of patients with atrial fibrillation undergoing percutaneous coronary intervention with stent implantation: in-hospital-data from the Atrial Fibrillation undergoing Coronary Artery Stenting study.

    PubMed

    Schlitt, Axel; Rubboli, Andrea; Lip, Gregory Y H; Lahtela, Heli; Valencia, Josè; Karjalainen, Pasi P; Weber, Michael; Laine, Mika; Kirchhof, Paulus; Niemelä, Matti; Vikman, Saila; Buerke, Michael; Airaksinen, K E Juhani

    2013-12-01

    Current recommendations on the management of patients with atrial fibrillation (AF) undergoing percutaneous coronary intervention with stent (PCI-S) essentially derive from small, single-center, retrospective datasets. To obtain larger and better quality data, we carried out the prospective, multicenter Atrial Fibrillation undergoing Coronary Artery Stenting (AFCAS) study. Therefore, consecutive patients with history of or ongoing AF undergoing PCI-S were enrolled, and occurrence of adverse ischemic and bleeding events recorded during 12 months follow-up. In this article, we report the in-hospital observations. Out of the 963 patients, in the majority of cases (49.1%) AF was permanent. The associated risk of stroke, as defined by a CHADS2 -score ≥2, was in 70% of patients moderate to high. Upon enrollment in the registry, 69.3% of patients were on VKA therapy. Overall occurrence of in-hospital major adverse cardiac events was 4.5% (cardiovascular death 1.9%, urgent revascularization in 1.5%, and stroke/arterial thromboembolism in 0.6%). Bleeding complications occurred in 7.1% of patients, being severe in 2.5%. In a logistic regression analysis, no risk factor was independently associated with bleeding events, whereas Clopidogrel treatment decreased and female gender/treatment with gpIIb/IIIa-antagonists, respectively increased the risk for the combined ischemic endpoint. The majority of AF patients undergoing PCI-S are at high stroke risk, and therefore VKA treatment should not be withdrawn and combined anticoagulant and antiplatelet treatment is warranted. Current management appears largely in accordance with current recommendations, whereby accounting for the limited occurrence of in-hospital adverse ischemic and bleeding events.

  5. High versus low-pressure balloon inflation during multilinktrade mark stent implantation: acute and long-term angiographic results.

    PubMed

    Caixeta, A M; Brito, F S; Rati, M; Perin, M A; da Luz, P L; Ramires, J A; Ambrose, J A; Martinez, E E

    2000-08-01

    We compared the impact of low and high-pressure balloon inflation on acute and late angiographic results of Multilink stent. Low-pressure balloon inflation (9.5 +/- 1.9 atm) was used in 43 stents and high pressure (17.1 +/- 1.5 atm) in 44. A larger immediate luminal gain was achieved in stents with high-pressure balloon inflation (1.80 +/- 0.26 vs. 1.47 +/- 0.62; P = 0.002), resulting in a larger mean diameter in this group (2.71 +/- 0.37 vs. 2.48 +/- 0.47; P = 0.017). At follow-up, a larger luminal diameter was achieved in the high pressure group (1.93 +/- 0.72 vs. 1.45 +/- 0.66; P = 0.002) and a trend to a lower rate of angiographic restenosis (15% vs. 38%, P = 0.08).

  6. Impact of arterial remodelling and plaque rupture on target and non‐target lesion revascularisation after stent implantation in patients with acute coronary syndrome: an intravascular ultrasound study

    PubMed Central

    Okura, Hiroyuki; Taguchi, Haruyuki; Kubo, Tomoichiro; Toda, Iku; Yoshiyama, Minoru; Yoshikawa, Junichi; Yoshida, Kiyoshi

    2007-01-01

    Objectives To investigate the impact of arterial remodelling on long‐term clinical outcome after stent implantation in patients with acute coronary syndrome (ACS). Methods 134 patients with ACS were enrolled. External elastic membrane (EEM) cross‐sectional area (CSA) and lumen CSA were measured. Plaque and media CSA was calculated as EEM minus lumen CSA. Final minimal stent area (MSA) was also measured after stenting. Positive remodelling (PR) was defined as the ratio of the EEM CSA at the target lesion to that at the proximal reference of >1.05, and intermediate or negative remodelling (IR/NR) was defined as that of ⩽1.05. Results Although final MSA was similar, target lesion revascularisation (TLR) rates at 2 years were significantly higher in patients with PR (33.7%) than in those with IR/NR (13.7%; p = 0.01). In addition, non‐TLR rates were also significantly higher in patients with PR (42.2%) than in those with IR/NR (23.5%; p = 0.03). Cardiac event‐free survival (for events such as death, myocardial infarction, TLR and non‐TLR) was significantly lower in patients with PR than in those with IR/NR (log rank, p = 0.001). By multivariate logistic regression analysis, PR (χ2 6.57, OR 2.70; 95% CI, 1.27 to 5.78; p = 0.01) and plaque rupture (χ2 4.17, OR 2.38; 95% CI, 1.04 to 5.45; p = 0.04) were independent predictors of cardiac events. Conclusion In patients with ACS, PR and intravascular ultrasound findings that may correspond with plaque rupture predict cardiac events including both TLR and non‐TLR at 2 years. PMID:17395673

  7. Endovascular stent implantation in the coeliac and superior mesenteric arteries in the treatment of chronic mesenteric ischemia.

    PubMed

    Srimannarayana, J; Babu, K Jagadeesh; Ramesh, K G; Raju, P V R; Sharma, Anurag

    2006-01-01

    Mesenteric ischemia is a rare but serious cause of abdominal pain.We present the case of a man who had symptomatic mesenteric ischemia, secondary to a superior mesenteric artery stenosis in conjunction with a coeliac artery stenosis. He was treated with balloon angioplasty and stent insertion, and showed good symptomatic improvement. PMID:18989062

  8. Clinical predictors of mortality following rotational atherectomy and stent implantation in high‐risk patients: A single center experience

    PubMed Central

    Édes, István F.; Ruzsa, Zoltán; Szabó, György; Nardai, Sándor; Becker, Dávid; Benke, Kálmán; Szilveszter, Bálint

    2015-01-01

    Objectives Our aim was to assess the procedural success and determine the clinical predictors of postprocedure mortality, following rotational atherectomy (RA) and stenting in high‐risk patients. Background RA is mainly used to facilitate stenting in complex lesions. Outcomes involving RA and stenting have been investigated, yet high‐risk patients have not been adequately described. Methods Data of 218 consecutive patients who underwent RA were evaluated in a prospective register. Primary endpoints were the angiographic success and long‐term mortality. Secondary endpoints were procedural success, consumption of the angioplasty equipment, and periprocedural major adverse cardiac events. The impact of the relevant angiographic and clinical characteristics on long‐term mortality was analyzed using uni‐ and multivariate Cox regression analysis. Results Mean age of the patients was 70 ± 8.2 years, diabetes was present in 44%, and chronic renal failure in 29%. Prior myocardial infarction and three‐vessel disease amounted to 42.2% and 32.6%, respectively. Altogether, 52.8% of patients underwent RA after a failed, non‐RA intervention attempt, and 30.7% of cases presented as acute coronary syndromes. Angiographic success was 100%, and all patients received stents after RA. Periprocedural major adverse cardiac events occurred in five (2.3%) patients. Postprocedural death was investigated, with a mean follow‐up of 36 months. Mortality amounted to 37.2%. Multivariate analysis revealed that left ventricular ejection fraction < 50%, glomerular filtration rate < 60 ml/min, cardiogenic shock, and diabetes were the only independent mortality predictors. Conclusions We have found that RA and stenting is feasible and viable in an elderly high‐risk population, with exceptional procedural success and acceptable long‐term results. © 2015 Wiley Periodicals, Inc. PMID:26032270

  9. Impact of Stent Design on In-Stent Stenosis in a Rabbit Iliac Artery Model

    SciTech Connect

    Sommer, C. M. Grenacher, L.; Stampfl, U.; Arnegger, F. U.; Rehnitz, C.; Thierjung, H.; Stampfl, S.; Berger, I.; Richter, G. M.; Kauczor, H. U.; Radeleff, B. A.

    2010-06-15

    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, 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.

  10. Wave reflection at a stent.

    PubMed

    Crespo, Antonio; García, Javier; Manuel, Fernando

    2013-01-01

    A simple analytical expression has been derived to calculate the characteristics of a wave that reflects at a stent implanted in a uniform vessel. The stent is characterized by its length and the wave velocity in the stented region. The reflected wave is proportional to the time derivative of the incident wave. The reflection coefficient is a small quantity of the order of the length of the stent divided by the wavelength of the unstented vessel. The results obtained coincide with those obtained numerically by Charonko et al. The main simplifications used are small amplitude of the waves so that equations can be linearized and that the length of the stent is small enough so that the values of the wave functions are nearly uniform along the stent. Both assumptions hold in typical situations. PMID:23516957

  11. Wave reflection at a stent.

    PubMed

    Crespo, Antonio; García, Javier; Manuel, Fernando

    2013-01-01

    A simple analytical expression has been derived to calculate the characteristics of a wave that reflects at a stent implanted in a uniform vessel. The stent is characterized by its length and the wave velocity in the stented region. The reflected wave is proportional to the time derivative of the incident wave. The reflection coefficient is a small quantity of the order of the length of the stent divided by the wavelength of the unstented vessel. The results obtained coincide with those obtained numerically by Charonko et al. The main simplifications used are small amplitude of the waves so that equations can be linearized and that the length of the stent is small enough so that the values of the wave functions are nearly uniform along the stent. Both assumptions hold in typical situations.

  12. Analysis of the stent expansion in a stenosed artery using finite element method: application to stent versus stent study.

    PubMed

    Imani, S Misagh; Goudarzi, A M; Ghasemi, S E; Kalani, A; Mahdinejad, J

    2014-10-01

    In this article, finite element method is used to investigate the mechanical behavior of a stent and to determine the biomechanical interaction between the stent and the artery in a stenting procedure. The main objective of this study is to reach to a model close to a real condition of coronary stent placement. Unlike most of the models proposed in the literature, all the steps of the deployment of a stent in the stenotic vessel (i.e. pressure increasing, constant load pressure and pressure decreasing) are simulated in this article to show the behavior of the stent in different stages of implantation. The results indicate that the first step of deployment, that is, pressure increasing, plays a main role in the success of stent implantation. So that, in order to compare the behavior of different types of stents, it is sufficient to compare their behavior at the end of pressure increasing step. In order to show the application of the findings in stent versus stent studies, three commercially available stents (the Palmaz-Schatz, Multi-Link and NIR stents) are modeled and their behavior is compared at the end of pressure increasing step. The effect of stent design on the restenosis rate is investigated. According to the findings, the possibility of restenosis is lower for Multi-Link and NIR stents in comparison with Palmaz-Schatz stent which is in good agreement with clinical results. Therefore, the testing methodology outlined here is proposed as a simple and economical alternative for "stent versus stent" complicated clinical trials.

  13. iStent® Trabecular Microbypass Stent: An Update.

    PubMed

    Resende, Arthur Fernandes; Patel, Neal Sanjay; Waisbourd, Michael; Katz, L Jay

    2016-01-01

    Due to the high rates of complications and failure experienced with current glaucoma procedures, there is a continuous search for a safer and more effective glaucoma surgery. A new class of procedures termed minimally invasive glaucoma surgeries (MIGS) aim to fill this void by offering an alternative method of IOP reduction associated with markedly reduced complication rates and shorter recovery times. The iStent, a trabecular microbypass stent, is a MIGS device that has quickly gained popularity. The device allows aqueous humor to directly drain from the anterior chamber into Schlemm's canal by bypassing an obstructed trabecular meshwork. This review examines publications about the iStent, focusing on the device's efficacy, safety, and cost when a single iStent or multiple iStents are implanted in combination with cataract surgery or as a solo procedure. Current data suggest that the iStent is a safe and effective tool in the management of mild-to-moderate glaucoma, notable for its limited complications and absence of serious adverse events following implantation. As valuable experience is gained performing ab interno MIGS, increasing familiarity with angle anatomy and iStent placement, and as newer stent designs are developed, there is promise of continual improvement in the surgical management of glaucoma.

  14. iStent® Trabecular Microbypass Stent: An Update

    PubMed Central

    Resende, Arthur Fernandes; Patel, Neal Sanjay; Waisbourd, Michael; Katz, L. Jay

    2016-01-01

    Due to the high rates of complications and failure experienced with current glaucoma procedures, there is a continuous search for a safer and more effective glaucoma surgery. A new class of procedures termed minimally invasive glaucoma surgeries (MIGS) aim to fill this void by offering an alternative method of IOP reduction associated with markedly reduced complication rates and shorter recovery times. The iStent, a trabecular microbypass stent, is a MIGS device that has quickly gained popularity. The device allows aqueous humor to directly drain from the anterior chamber into Schlemm's canal by bypassing an obstructed trabecular meshwork. This review examines publications about the iStent, focusing on the device's efficacy, safety, and cost when a single iStent or multiple iStents are implanted in combination with cataract surgery or as a solo procedure. Current data suggest that the iStent is a safe and effective tool in the management of mild-to-moderate glaucoma, notable for its limited complications and absence of serious adverse events following implantation. As valuable experience is gained performing ab interno MIGS, increasing familiarity with angle anatomy and iStent placement, and as newer stent designs are developed, there is promise of continual improvement in the surgical management of glaucoma. PMID:27413541

  15. Evaluation of safety and efficacy of NexGen – an ultrathin strut and hybrid cell design cobalt-chromium bare metal stent implanted in a real life patient population – the Polish NexGen Registry

    PubMed Central

    Milewski, Krzysztof; Gąsior, Paweł; Samborski, Stefan; Buszman, Piotr P.; Błachut, Aleksandra; Młodziankowski, Adam; Mendyk, Artur; Król, Marek; Wojakowski, Wojciech; Buszman, Paweł E.

    2016-01-01

    Introduction Despite the dominance of drug-eluting stents in modern interventional cardiology, there is still a niche for bare metal stents. Aim The aim of the Polish NexGen registry was to evaluate the safety and efficacy of a new generation cobalt-chromium NexGen stent in a real life patient population. Material and methods A prospective multi-center registry was conducted in five clinical sites of American Heart of Poland. Three hundred and eighty-three patients who underwent percutaneous coronary intervention (PCI) with NexGen stent implantation were included. Clinical follow-up was performed at 1, 6 and 12 months. Additionally, a group of 42 randomly selected patients underwent control angiography at 6 months (10.96% of study population). The primary endpoint was occurrence of target vessel revascularization (TVR) at 6-month follow-up. Angiographic endpoints included rates of binary restenosis and late lumen loss at 6-month follow-up based on QCA analysis. Multivessel disease was present in more than 70% of patients, and 52.4% of lesions were complex. The main indications for angiography were non-ST elevation acute coronary syndromes (54.8%) and ST elevation myocardial infarction (34.99%). Results At 6-month follow-up 47 (12.7%) patients reached the primary endpoint of TVR. The composite of major acute cardiac event rates at 30-day and 6- and 12-month follow-up was 6.01% (n = 23), 18.5% (n = 69) and 25.21% (n = 92) respectively. Control angiography performed after 6 months showed in-stent late loss of 0.66 ±0.71 mm and a binary restenosis rate of 16.7%. Conclusions Our study showed that PCI with the NexGen stent is safe and effective at 6- and 12-month follow-up. Angiographic results showed a satisfactory restenosis rate and low late lumen loss. PMID:27625684

  16. Evaluation of safety and efficacy of NexGen – an ultrathin strut and hybrid cell design cobalt-chromium bare metal stent implanted in a real life patient population – the Polish NexGen Registry

    PubMed Central

    Milewski, Krzysztof; Gąsior, Paweł; Samborski, Stefan; Buszman, Piotr P.; Błachut, Aleksandra; Młodziankowski, Adam; Mendyk, Artur; Król, Marek; Wojakowski, Wojciech; Buszman, Paweł E.

    2016-01-01

    Introduction Despite the dominance of drug-eluting stents in modern interventional cardiology, there is still a niche for bare metal stents. Aim The aim of the Polish NexGen registry was to evaluate the safety and efficacy of a new generation cobalt-chromium NexGen stent in a real life patient population. Material and methods A prospective multi-center registry was conducted in five clinical sites of American Heart of Poland. Three hundred and eighty-three patients who underwent percutaneous coronary intervention (PCI) with NexGen stent implantation were included. Clinical follow-up was performed at 1, 6 and 12 months. Additionally, a group of 42 randomly selected patients underwent control angiography at 6 months (10.96% of study population). The primary endpoint was occurrence of target vessel revascularization (TVR) at 6-month follow-up. Angiographic endpoints included rates of binary restenosis and late lumen loss at 6-month follow-up based on QCA analysis. Multivessel disease was present in more than 70% of patients, and 52.4% of lesions were complex. The main indications for angiography were non-ST elevation acute coronary syndromes (54.8%) and ST elevation myocardial infarction (34.99%). Results At 6-month follow-up 47 (12.7%) patients reached the primary endpoint of TVR. The composite of major acute cardiac event rates at 30-day and 6- and 12-month follow-up was 6.01% (n = 23), 18.5% (n = 69) and 25.21% (n = 92) respectively. Control angiography performed after 6 months showed in-stent late loss of 0.66 ±0.71 mm and a binary restenosis rate of 16.7%. Conclusions Our study showed that PCI with the NexGen stent is safe and effective at 6- and 12-month follow-up. Angiographic results showed a satisfactory restenosis rate and low late lumen loss.

  17. Validation of the Ability of SYNTAX and Clinical SYNTAX Scores to Predict Adverse Cardiovascular Events After Stent Implantation: A Systematic Review and Meta-Analysis.

    PubMed

    Chen, JiaYuan; Tang, Buzhou; Lin, YongQing; Ru, Ying; Wu, MaoXiong; Wang, Xiaolong; Chen, Qingcai; Chen, YangXin; Wang, JingFeng

    2016-10-01

    To compare the predicative ability of SYNTAX (Synergy between PCI with Taxus and Cardiac Surgery) and clinical SYNTAX scores for major adverse cardiac events (MACEs) after stent implantation in patients with coronary artery disease (CAD). Studies were identified by electronic and manual searches. Twenty-six studies were included in the meta-analysis. The pooled C-statistics of SYNTAX score for 1- and 5-year all-cause mortality (ACM) were 0.65 (95% confidence interval [CI]: 0.61-0.68) and 0.62 (95% CI: 0.59-0.65), respectively, with weak heterogeneity. The 1- and 5-year ACM pooled C-statistics for clinical SYNTAX scores were significantly higher at 0.77 and 0.71, respectively (Ps < .05). Both scoring systems predicted 1- and 5-year MACE equally well. The pooled risk ratio of the SYNTAX score for predicting 1-year ACM per unit was 1.04 (95% CI: 1.03-1.05). Calibration analysis indicated SYNTAX scores overestimated the risk of major adverse cardiac and cerebrovascular events in each risk stratum. The SYNTAX score demonstrated minimal discrimination in predicting 1- or 5-year adverse cardiovascular events after percutaneous coronary intervention in patients with CAD. The clinical SYNTAX score could further improve the predictive capability for ACM but not MACE.

  18. Biological behaviour of human umbilical artery smooth muscle cell grown on nickel-free and nickel-containing stainless steel for stent implantation

    PubMed Central

    Li, Liming; An, Liwen; Zhou, Xiaohang; Pan, Shuang; Meng, Xin; Ren, Yibin; Yang, Ke; Guan, Yifu

    2016-01-01

    To evaluate the clinical potential of high nitrogen nickel-free austenitic stainless steel (HNNF SS), we have compared the cellular and molecular responses of human umbilical artery smooth muscle cells (HUASMCs) to HNNF SS and 316L SS (nickel-containing austenitic 316L stainless steel). CCK-8 analysis and flow cytometric analysis were used to assess the cellular responses (proliferation, apoptosis, and cell cycle), and quantitative real-time PCR (qRT-PCR) was used to analyze the gene expression profiles of HUASMCs exposed to HNNF SS and 316L SS, respectively. CCK-8 analysis demonstrated that HUASMCs cultured on HNNF SS proliferated more slowly than those on 316L SS. Flow cytometric analysis revealed that HNNF SS could activate more cellular apoptosis. The qRT-PCR results showed that the genes regulating cell apoptosis and autophagy were up-regulated on HNNF SS. Thus, HNNF SS could reduce the HUASMC proliferation in comparison to 316L SS. The findings furnish valuable information for developing new biomedical materials for stent implantation. PMID:26727026

  19. Biological behaviour of human umbilical artery smooth muscle cell grown on nickel-free and nickel-containing stainless steel for stent implantation

    NASA Astrophysics Data System (ADS)

    Li, Liming; An, Liwen; Zhou, Xiaohang; Pan, Shuang; Meng, Xin; Ren, Yibin; Yang, Ke; Guan, Yifu

    2016-01-01

    To evaluate the clinical potential of high nitrogen nickel-free austenitic stainless steel (HNNF SS), we have compared the cellular and molecular responses of human umbilical artery smooth muscle cells (HUASMCs) to HNNF SS and 316L SS (nickel-containing austenitic 316L stainless steel). CCK-8 analysis and flow cytometric analysis were used to assess the cellular responses (proliferation, apoptosis, and cell cycle), and quantitative real-time PCR (qRT-PCR) was used to analyze the gene expression profiles of HUASMCs exposed to HNNF SS and 316L SS, respectively. CCK-8 analysis demonstrated that HUASMCs cultured on HNNF SS proliferated more slowly than those on 316L SS. Flow cytometric analysis revealed that HNNF SS could activate more cellular apoptosis. The qRT-PCR results showed that the genes regulating cell apoptosis and autophagy were up-regulated on HNNF SS. Thus, HNNF SS could reduce the HUASMC proliferation in comparison to 316L SS. The findings furnish valuable information for developing new biomedical materials for stent implantation.

  20. Does endovascular treatment of infra-inguinal arterial disease with drug-eluting stents offer better results than angioplasty with or without bare metal stents?

    PubMed

    Antoniou, George A; Georgakarakos, Efstratios I; Antoniou, Stavros A; Georgiadis, George S

    2014-08-01

    A best evidence topic in vascular and endovascular surgery was developed according to a structured protocol. The question addressed was whether treatment of infra-inguinal arterial occlusive disease with drug-eluting stents (DESs) provides improved outcomes compared with bare metal stents (BMSs) or percutaneous balloon angioplasty (PTA) alone. Altogether, 136 papers were found using the reported searches, of which 5 provided the best evidence to answer the question. All papers represent either level 1 or 2 evidence. The authors, journal, date, country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. Main outcome measures varied among the studies, and included patency, in-stent restenosis, target lesion revascularization, major adverse events, clinical improvement and limb salvage. Evidence on the comparative efficacy of DESs in femoro-popliteal arterial disease is mainly based on two randomized, controlled trials. Paclitaxel-eluting stents were evaluated in the Zilver PTX trial and demonstrated superior 2-year results to either BMSs or PTA, as indicated/shown by patency (DES vs PTA, 74.8 vs 26.5%, P < 0.01), clinical benefit (DES vs PTA, P < 0.01) and event-free survival (DES vs PTA, 86.6 vs 77.9%, P = 0.02). However, the SIROCCO trial found that the sirolimus-eluting stent did not exhibit statistically significant differences in 2-year in-stent restenosis (22.9 vs 21.1%) and target lesion revascularization (6 vs 13%) compared with the BMS. Treatment of infra-politeal arterial disease with DESs was related with superior outcomes to those of BMSs, as indicated/shown by patency, freedom from target lesion revascularization and freedom from major adverse events. Furthermore, the ACHILLES trial, the only published trial comparing the infra-popliteal DES with PTA, revealed lower angiographic restenosis (22.4 vs 41.9%, P = 0.019) and greater vessel patency (75 vs 57.1%, P = 0.025) in the DES group at 1 year

  1. Nitinol Esophageal Stents: New Designs and Clinical Indications

    SciTech Connect

    Strecker, Ernst-Peter; Boos, Irene; Vetter, Sylvia; Strohm, Michael; Domschke, Sigurd

    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 stent 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.

  2. The clinical outcomes of triple antiplatelet therapy versus dual antiplatelet therapy for high-risk patients after coronary stent implantation: a meta-analysis of 11 clinical trials and 9,553 patients

    PubMed Central

    Fan, Zhong-Guo; Ding, Guo-Bin; Li, Xiao-Bo; Gao, Xiao-Fei; Gao, Ya-Li; Tian, Nai-Liang

    2016-01-01

    Background The optimal antiplatelet regimen after in-coronary intervention among patients presenting with complex coronary artery lesions or acute coronary syndrome (ACS) has remained unclear. This study sought to evaluate the clinical outcomes of triple antiplatelet treatment (TAPT) (cilostazol added to aspirin plus clopidogrel) in these patients. Methods The PubMed, EMBASE, MEDLINE, and other Internet sources were searched for relevant articles. The primary end point was major adverse cardiac events (MACE), including all-cause mortality, myocardial infarction, and target vessel revascularization. The incidence of definite/probable stent thrombosis and bleeding were analyzed as the safety end points. Results Eleven clinical trials involving 9,553 patients were analyzed. The risk of MACE was significantly decreased following TAPT after stent implantation in the ACS subgroup (odds ratio [OR]: 0.72; 95% confidence interval [CI]: 0.61–0.85; P<0.001), which might mainly result from the lower risk of all-cause mortality in this subset (OR: 0.62; 95% CI: 0.48–0.80; P<0.001). The risk of bleeding was not increased with respect to TAPT. Conclusion TAPT after stent implantation was associated with feasible benefits on reducing the risk of MACE, especially on reducing the incidence of all-cause mortality among patients suffering from ACS, without higher incidence of bleeding. Larger and more powerful randomized trials are still warranted to prove the superiority of TAPT for such patients. PMID:27799743

  3. A computational study of the hemodynamic impact of open- versus closed-cell stent design in carotid artery stenting.

    PubMed

    De Santis, Gianluca; Trachet, Bram; Conti, Michele; De Beule, Matthieu; Morbiducci, Umberto; Mortier, Peter; Segers, Patrick; Verdonck, Pascal; Verhegghe, Benedict

    2013-07-01

    The aim of this study is to analyze the shape and flow changes of a patient-specific carotid artery after carotid artery stenting (CAS) performed using an open-cell (stent-O) or a closed-cell (stent-C) stent design. First, a stent reconstructed from micro-computed tomography (microCT) is virtually implanted in a left carotid artery reconstructed from CT angiography. Second, an objective analysis of the stent-to-vessel apposition is used to quantify the lumen cross-sectional area and the incomplete stent apposition (ISA). Third, the carotid artery lumen is virtually perfused in order to quantify its resistance to flow and its exposure to atherogenic or thrombogenic hemodynamic conditions. After CAS, the minimum cross-sectional area of the internal carotid artery (ICA) (external carotid artery [ECA]) changes by +54% (-12%) with stent-O and +78% (-17%) with stent-C; the resistance to flow of the ICA (ECA) changes by -21% (+13%) with stent-O and -26% (+18%) with stent-C. Both stent designs suffer from ISA but the malapposed stent area is larger with stent-O than stent-C (29.5 vs. 14.8 mm(2) ). The untreated vessel is not exposed to atherogenic flow conditions whereas an area of 67.6 mm(2) (104.9) occurs with stent-O (stent-C). The area of the stent surface exposed to thrombogenic risk is 5.42 mm(2) (7.7) with stent-O (stent-C). The computer simulations of stenting in a patient's carotid artery reveal a trade-off between cross-sectional size and flow resistance of the ICA (enlarged and circularized) and the ECA (narrowed and ovalized). Such a trade-off, together with malapposition, atherogenic risk, and thrombogenic risk is stent-design dependent. PMID:23578331

  4. Late Stent Expansion and Neointimal Proliferation of Oversized Nitinol Stents in Peripheral Arteries

    SciTech Connect

    Zhao, Hugh Q. Nikanorov, Alexander; Virmani, Renu; Jones, Russell; Pacheco, Erica; Schwartz, Lewis B.

    2009-07-15

    For peripheral endovascular intervention, self-expanding (SE) stents are commonly oversized in relation to target arteries to assure optimal wall apposition and prevent migration. However, the consequences of oversizing have not been well studied. The purpose of this study was to examine the effects of SE stent oversizing (OS) with respect to the kinetics of late stent expansion and the long-term histological effects of OS. Pairs of overlapped 8 x 28-mm Nitinol SE stents were implanted into the iliofemoral arteries of 14 Yucatan swine. Due to variations in target artery size, the stent-to-artery ratio ranged from 1.2:1 to 1.9:1. Lumen and stent diameters were assessed by quantitative angiography at the time of implantation. Following angiographic assessment at 6 months, stented arteries were perfusion-fixed, sectioned, and stained for histological analysis. Immediately following implantation, the stents were found to be expanded to a range of 4.7-7.1 mm, largely conforming to the diameter of the recipient target artery. The stents continued to expand over time, however, and all stents had enlarged to nearly their 8-mm nominal diameter by 6 months. The histological effects of OS were profound, with marked increases in injury and luminal area stenosis, including a statistically significant linear correlation between stent-to-artery ratio and area stenosis. In this experimental model of peripheral endovascular intervention, oversized Nitinol SE stents are constrained by their target artery diameter upon implantation but expand to their nominal diameter within 6 months. Severe OS (stent-to-artery ratio >1.4:1) results in a profound long-term histological response including exuberant neointimal proliferation and luminal stenosis.

  5. Focal stent collapse in a patient with systemic sclerosis.

    PubMed

    Di Francesco, L; Finci, L; Reimers, B; Di Mario, C; Colombo, A

    1998-05-01

    We report a patient with systemic sclerosis having implantation of a 35 mm beStent with immediate success but developing angina at follow-up. A focal stent collapse with focal hyperplasia in and outside the stent was documented by ultrasound after 2 mos. A 14mm Palmaz-Schatz stent was successfully deployed into the collapsed beStent, with good 6-mo angiographic result. The stent collapse was probably due to unequal distribution of radial forces and possibly reactive hyperplasia in this unique patient with systemic sclerosis.

  6. In vivo and in vitro characterization of poly(styrene-b-isobutylene-b-styrene) copolymer stent coatings for biostability, vascular compatibility and mechanical integrity.

    PubMed

    Strickler, Fred; Richard, Robert; McFadden, Sharon; Lindquist, Jeff; Schwarz, Marlene C; Faust, Rudolf; Wilson, Gregory J; Boden, Mark

    2010-02-01

    The TAXUS Express 2 Paclitaxel Eluting Coronary Stent System employs a coating consisting of the thermoplastic elastomer, poly(styrene-b-isobutylene-b-styrene; SIBS), selected for its drug-eluting characteristics, vascular compatibility, mechanical properties, and biostability. This study was conducted to evaluate the impact of different SIBS (17-51 mole % styrene) compositions on mechanical properties, chemical stability, and vascular compatibility. Mechanical property (stress-strain measurements) and stability studies were conducted on polymer films with five different styrene contents (17, 24, 32, 39, and 51 mole %). The ultimate tensile strength did not change significantly with composition, but the elongation at break decreased with increased styrene content. A pulsatile fatigue test further confirmed the mechanical stability of SIBS up to 39 mole % styrene. The vascular compatibility of five different SIBS compositions was assessed using SIBS-only coated stents, in the coronary and carotid arteries in a porcine model study. The stability of the vessel wall, rate/degree of endothelialization, inflammation, and thrombus at timepoints from 30 to 180 days were evaluated. The results confirm vascular compatibility over the range of 17-51 mole % styrene.

  7. A Migrated Aortic Stent Graft Causing Erosive Spondylopathy

    SciTech Connect

    Gestrich, Christopher Probst, Chris; Wilhelm, Kai; Schiller, Wolfgang

    2013-12-15

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

  8. Very late in-stent thrombosis 9 years after double stent treatment of fusiform basilar artery aneurysm.

    PubMed

    Juszkat, Robert; Stanislawska, Katarzyna; Wasik, Norbert; Jankowski, Roman; Liebert, Włodzimierz

    2015-06-01

    Endovascular treatment seems to be the best approach to posterior circulation fusiform aneurysms. Double stent techniques are frequently used to occlude basilar artery dilations. Unfortunately, there is a limited number of studies that have followed up with patients over prolonged periods of time in order to evaluate delayed complications, such as stenosis, thrombosis or migration of stents. We present an unusual case of in-stent thrombosis 9 years after basilar artery aneurysm treatment to caution about complications associated with double stent implantation.

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

    SciTech Connect

    Wilhelm, K.E. Grabolle, B.; Urbach, H.; Tolba, R.; Schild, H.; Paulsen, F.

    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 without 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.

  10. Flexibility and trackability of laser cut coronary stent systems.

    PubMed

    Szabadíts, Péter; Puskás, Zsolt; Dobránszky, János

    2009-01-01

    Coronary stents are the most important supports in present day cardiology. Flexibility and trackability are two basic features of stents. In this paper, four different balloon-expandable coronary stent systems were investigated mechanically in order to compare their suitability. The coronary stent systems were assessed by measurements of stent flexibility as well as by comparison of forces during simulated stenting in a self-investigated coronary vessel model. The stents were cut by laser from a single tube of 316L stainless steel or L-605 (CoCr) cobalt chromium alloy. The one-and four-point bending tests were carried out to evaluate the stent flexibility E x I (Nmm(2)), under displacement control in crimped and expanded configurations. The flexibility of stents would be rather dependent on the design than on raw material. In general a more flexible stent needs lower tracking force during the implantation. The L-605 raw material stents need lower track force to pass through in the vessel model than the 316L raw material stents. The sort and long stents passed through the curved vessel model in different ways. The long stents nestled to the vessel wall at the outer arc and bent, while the short stents did not bend in the curve, only the delivery systems bent.

  11. The risk of bleeding of triple therapy with vitamin K-antagonists, aspirin and clopidogrel after coronary stent implantation: Facts and questions

    PubMed Central

    Rubboli, Andrea

    2011-01-01

    Background Triple therapy (TT) with vitamin K-antagonists (VKA), aspirin and clopidogrel is the recommended antithrombotic treatment following percutaneous coronary intervention with stent implantation (PCI-S) in patients with an indication for oral anticoagulation. TT is associated with an increased risk of bleeding, but available evidence is flawed by important limitations, including the limited size and the retrospective design of most of the studies, as well as the rare reporting of the incidence of in-hospital bleeding and the treatment which was actually ongoing at the time of bleeding. Since the perceived high bleeding risk of TT may deny patients effective strategies, the determination of the true safety profile of TT is of paramount importance. Methods All the 27 published studies where the incidence of bleeding at various time points during follow-up has been reported separately for patients on TT were reviewed, and the weakness of the data was analyzed. Results The absolute incidence of major bleeding upon discharge at in-hospital, ≤ 1 month, 6 months, 12 months and ≥ 12 months was: 3.3% ± 1.9%, 5.1% ± 6.7%, 8.0% ± 5.2%, 9.0% ± 8.0, and 6.2% ± 7.8%, respectively, and not substantially different from that observed in previous studies with prolonged dual antiplatelet treatment with aspirin and clopidogrel. Conclusions While waiting for the ongoing, large-scale, registries and clinical trials to clarify the few facts and to answer the many questions regarding the risk of bleeding of TT, this treatment should not be denied to patients with an indication for VKA undergoing PCI-S provided that the proper measures and cautions are implemented. PMID:22783307

  12. 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.

  13. Rapid virtual stenting for intracranial aneurysms

    NASA Astrophysics Data System (ADS)

    Zhao, Liang; Chen, Danyang; Chen, Zihe; Wang, Xiangyu; Paliwal, Nikhil; Xiang, Jianping; Meng, Hui; Corso, Jason J.; Xu, Jinhui

    2016-03-01

    The rupture of Intracranial Aneurysms is the most severe form of stroke with high rates of mortality and disability. One of its primary treatments is to use stent or Flow Diverter to divert the blood flow away from the IA in a minimal invasive manner. To optimize such treatments, it is desirable to provide an automatic tool for virtual stenting before its actual implantation. In this paper, we propose a novel method, called ball-sweeping, for rapid virtual stenting. Our method sweeps a maximum inscribed sphere through the aneurysmal region of the vessel and directly generates a stent surface touching the vessel wall without needing to iteratively grow a deformable stent surface. Our resulting stent mesh has guaranteed smoothness and variable pore density to achieve an enhanced occlusion performance. Comparing to existing methods, our technique is computationally much more efficient.

  14. Rapid Virtual Stenting for Intracranial Aneurysms

    PubMed Central

    Zhao, Liang; Chen, Danyang; Chen, Zihe; Wang, Xiangyu; Paliwal, Nikhil; Xiang, Jianping; Meng, Hui; Corso, Jason J.; Xu, Jinhui

    2016-01-01

    The rupture of Intracranial Aneurysms is the most severe form of stroke with high rates of mortality and disability. One of its primary treatments is to use stent or Flow Diverter to divert the blood flow away from the IA in a minimal invasive manner. To optimize such treatments, it is desirable to provide an automatic tool for virtual stenting before its actual implantation. In this paper, we propose a novel method, called ball-sweeping, for rapid virtual stenting. Our method sweeps a maximum inscribed sphere through the aneurysmal region of the vessel and directly generates a stent surface touching the vessel wall without needing to iteratively grow a deformable stent surface. Our resulting stent mesh has guaranteed smoothness and variable pore density to achieve an enhanced occlusion performance. Comparing to existing methods, our technique is computationally much more efficient. PMID:27346910

  15. Image-based mechanical analysis of stent deformation: concept and exemplary implementation for aortic valve stents.

    PubMed

    Gessat, Michael; Hopf, Raoul; Pollok, Thomas; Russ, Christoph; Frauenfelder, Thomas; Sündermann, Simon Harald; Hirsch, Sven; Mazza, Edoardo; Székely, Gábor; Falk, Volkmar

    2014-01-01

    An approach for extracting the radial force load on an implanted stent from medical images is proposed. To exemplify the approach, a system is presented which computes a radial force estimation from computer tomography images acquired from patients who underwent transcatheter aortic valve implantation (TAVI). The deformed shape of the implanted valve prosthesis' Nitinol frame is extracted from the images. A set of displacement vectors is computed that parameterizes the observed deformation. An iterative relaxation algorithm is employed to adapt the information extracted from the images to a finite-element model of the stent, and the radial components of the interaction forces between the stent and the tissue are extracted. For the evaluation of the method, tests were run using the clinical data from 21 patients. Stent modeling and extraction of the radial forces were successful in 18 cases. Synthetic test cases were generated, in addition, for assessing the sensitivity to the measurement errors. In a sensitivity analysis, the geometric error of the stent reconstruction was below 0.3 mm, which is below the image resolution. The distribution of the radial forces was qualitatively and quantitatively reasonable. An uncertainty remains in the quantitative evaluation of the radial forces due to the uncertainty in defining a radial direction on the deformed stent. With our approach, the mechanical situation of TAVI stents after the implantation can be studied in vivo, which may help to understand the mechanisms that lead to the complications and improve stent design. PMID:24626769

  16. A novel ferromagnetic thermo-stent for plaque stabilization that self-regulates the temperature.

    PubMed

    Matsui, Takemi; Matsumura, Kouji; Hagisawa, Kousuke; Ishihara, Masayuki; Ishizuka, Toshiaki; Suzuki, Minoru; Kurita, Akira; Kikuchi, Makoto

    2002-06-01

    The purpose of this study is to investigate the vascular wall with a thermally self-regulating, cylindrical stent made of a low Curie temperature ferromagnetic alloy. Physiologic saline was circulated in the silicone model vessel implanted with the stent. The stent-temperature remained nearly constant for variable saline flows, saline temperatures, and magnetic flux densities. Stent implants of this type in human blood vessels could potentially enable thermotherapy and temperature determination without catheterization.

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

    PubMed Central

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

    2016-01-01

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

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

    PubMed

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

    2016-01-01

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

  19. A randomised determination of the Effect of Fluvastatin and Atorvastatin on top of dual antiplatelet treatment on platelet aggregation after implantation of coronary drug-eluting stents. The EFA-Trial.

    PubMed

    Wenaweser, Peter; Eshtehardi, Parham; Abrecht, Linda; Zwahlen, Marcel; Schmidlin, Kurt; Windecker, Stephan; Meier, Bernhard; Haeberli, Andre; Hess, Otto M

    2010-09-01

    Drug-drug interaction between statins metabolised by cytochrome P450 3A4 and clopidogrel have been claimed to attenuate the inhibitory effect of clopidogrel. However, published data regarding this drug-drug interaction are controversial. We aimed to determine the effect of fluvastatin and atorvastatin on the inhibitory effect of dual antiplatelet therapy with acetylsalicylic acid (ASA) and clopidogrel. One hundred one patients with symptomatic stable coronary artery disease undergoing percutaneous coronary intervention and drug-eluting stent implantation were enrolled in this prospective randomised study. After an interval of two weeks under dual antiplatelet therapy with ASA and clopidogrel, without any lipid-lowering drug, 87 patients were randomised to receive a treatment with either fluvastatin 80 mg daily or atorvastatin 40 mg daily in addition to the dual antiplatelet therapy for one month. Platelet aggregation was assessed using light transmission aggregometry and whole blood impedance platelet aggregometry prior to randomisation and after one month of receiving assigned statin and dual antiplatelet treatment. Platelet function assessment after one month of statin and dual antiplatelet therapy did not show a significant change in platelet aggregation from 1st to 2nd assessment for either statin group. There was also no difference between atorvastatin and fluvastatin treatment arms. In conclusion, neither atorvastatin 40 mg daily nor fluvastatin 80 mg daily administered in combination with standard dual antiplatelet therapy following coronary drug-eluting stent implantation significantly interfere with the antiaggregatory effect of ASA and clopidogrel.

  20. 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

  1. Development of a polymer stent with shape memory effect as a drug delivery system.

    PubMed

    Wache, H M; Tartakowska, D J; Hentrich, A; Wagner, M H

    2003-02-01

    The article presents a new concept for vascular endoprothesis (stent). Almost all commercially available stents are made of metallic materials. A common after effect of stent implantation is restenosis. Several studies on metal stents coated with drug show, that the use of a drug delivery system may reduce restenosis. The purpose of this work is to develop a new stent for the drug delivery application. The shape memory properties of thermoplastic polyurethane allow to design a new fully polymeric self-expandable stent. The possibility to use the stent as a drug delivery system is described.

  2. Comparison of outcomes in patients with insulin-dependent versus non-insulin dependent diabetes mellitus receiving drug-eluting stents (from the first phase of the prospective multicenter German DES.DE registry).

    PubMed

    Akin, Ibrahim; Bufe, Alexander; Eckardt, Lars; Reinecke, Holger; Senges, Jochen; Richardt, Gert; Kuck, Karl-Heinz; Schneider, Steffen; Nienaber, Christoph A

    2010-11-01

    Drug-eluting stents have been effective in randomized controlled trials, but their safety and efficacy in patients with insulin-dependent diabetes has not been well studied. Baseline clinical and angiographic characteristics and in-hospital and follow-up events were recorded for enrolled patients. From October 2005 and October 2006, 581 patients with insulin-dependent diabetes and 1,078 with non-insulin-dependent diabetes treated with sirolimus- and paclitaxel-eluting stents were enrolled at 98 sites. The composite of death, myocardial infarction, and stroke, defined as major adverse cardiac and cerebrovascular events, as well as target vessel revascularization was used as the primary end point. Multiple logistic regression analysis was used to adjust for confounding parameters. Baseline clinical characteristics were more severe in patients with insulin-dependent diabetes, whereas descriptive characteristics were not unique. At 1-year follow-up, the comparison between the 2 groups revealed significantly higher rates of overall death (7.4% vs 4.6%, p <0.05), target vessel revascularization (15.1% vs 10.4%, p <0.05), and overall stent thrombosis (6.5% vs 4.1%, p <0.05) for insulin-dependent patients, while rates of major adverse cardiac and cerebrovascular events were not significantly different (12.8% vs 9.9%, p = 0.09). These results persisted even after risk adjustment for heterogenous baseline characteristics of the 2 groups. In conclusion, the data generated from the German Drug-Eluting Stent (DES.DE) registry revealed that even with drug-eluting stents, the annual risk for death, target vessel revascularization, and thrombotic events remains higher in patients with insulin-dependent diabetes compared to those with non-insulin-dependent diabetes.

  3. Degradation Model of Bioabsorbable Cardiovascular Stents

    PubMed Central

    Luo, Qiyi; Liu, Xiangkun; Li, Zhonghua; Huang, Chubo; Zhang, Wen; Meng, Juan; Chang, Zhaohua; Hua, Zezhao

    2014-01-01

    This study established a numerical model to investigate the degradation mechanism and behavior of bioabsorbable cardiovascular stents. In order to generate the constitutive degradation material model, the degradation characteristics were characterized with user-defined field variables. The radial strength bench test and analysis were used to verify the material model. In order to validate the numerical degradation model, in vitro bench test and in vivo implantation studies were conducted under physiological and normal conditions. The results showed that six months of degradation had not influenced the thermodynamic properties and mechanical integrity of the stent while the molecular weight of the stents implanted in the in vivo and in vitro models had decreased to 61.8% and 68.5% respectively after six month's implantation. It was also found that the degradation rate, critical locations and changes in diameter of the stents in the numerical model were in good consistency in both in vivo and in vitro studies. It implies that the numerical degradation model could provide useful physical insights and prediction of the stent degradation behavior and evaluate, to some extent, the in-vivo performance of the stent. This model could eventually be used for design and optimization of bioabsorbable stent. PMID:25365310

  4. [Changes of content of regulatory lymphocytes and concentration of soluble interleukine-2 receptor in blood of patients with ischemic heart disease after coronary artery angioplasty with implantation of stents with rapamycin covering].

    PubMed

    Potekhina, A V; Sokolov, V O; Pylaeva, E A; Provatorov, S I; Masenko, V P; Bosykh, E G; Noeva, E A; Krasnikova, T L; Aref'eva, T I

    2011-01-01

    We studied dynamics of content of subpopulation of lymphocytes including regulatory and effector T-lymphocytes as well as concentration of soluble form of interleukine-2 receptor (sCD25) in peripheral blood of patients after coronary stenting (CS) with implantation of stents with rapamycin covering (SRC). We included into the study 62 patients with stable effort II-III functional class angina. Coronary angiography (CA) was carried out in all, CS with implantation of 1 - 2 SRC - in 42 patients. Blood samples were taken before CA/CS, in 24, 48 hours, 7 days, 1 and 3 months after intervention. Content of T-, helper and cytotoxic T-cells, -, NK-, NKT-cells, activated effector T-lymphocytes (CD4+CD251owCD127high) and regulatory T-lymphocytes (CD4+CD25highCD1271ow) were measured by direct immunofluorescence and flow cytometry. CD4+ lymphocytes were isolated from mononuclear cell fraction of donor blood by magnetic separation. Content of regulatory T-lymphocytes in culture were determined by expression of a specific marker FOXP3+. Concentration of sCD25 was measured by chemiluminescent method. It was shown that content of main subpopulations of lymphocytes in blood changed after CS or CF. Blood content of regulatory T-lymphocytes and sCD25 significantly increased after 7 days and 1 month after CS but not after CA. Plasma sCD25 concentration correlated with content of regulatory T-lymphocytes in 1 month after SRC implantation. During cultivation of CD4+ lymphocytes in the presence of rapamycin we noted antiproliferative effect relative to FOXP3-cells and accumulation of regulatory +-lymphocytes. Thus implantation of SRC in coronary arteries leads to increase of number of circulating regulatory T-lymphocytes and blood concentration of sCD25. Changes of these parameters after CS can reflect peculiarities of local and systemic reaction arising in response to introduction of stent with drug covering and be significant for assessment of prognosis of the disease.

  5. Early and Long-Term Results of Stent Implantation for Aortic Coarctation in Pediatric Patients Compared to Adolescents: A Single Center Experience

    PubMed Central

    Bondanza, Sara; Calevo, Maria Grazia; Marasini, Maurizio

    2016-01-01

    Background. Stents have become the treatment of choice for native aortic coarctation in adults and adolescents, but in pediatric patients insufficient data are currently available to identify the best therapeutic option. Methods. To compare the outcomes of pediatric and adolescent patients, we retrospectively evaluated early and long-term results of stenting for aortic coarctation in 34 patients divided into 2 groups (A and B) composed, respectively, of 17 children (mean age 8.2 ± 2.3, weight ≤30 kg) and 17 adolescents (mean age 14.3 ± 1.7, weight >30 kg). Results. No significant differences in outcome were found between groups immediately after the procedure. In all of our patients, peak systolic gradient pressure significantly decreased after stenting from 43.7 ± 12 to 1.7 ± 3.1 mmHg in group A and from 39.4 ± 16.8 to 1.6 ± 3 in group B (p < 0.0001). We observed early and late adverse events in both groups: early femoral vessel injury or thrombosis was more frequent in younger patients, as well as restenosis due to vessel growth requiring stent redilatations, often complicated by stent fractures. Data from long-term follow-up showed that, in younger patients, stress-related hypertension was more frequent. Conclusions. The procedure was immediately safe and effective in both groups. Pediatric patients must be accurately selected before stenting because they could probably need reinterventions and stents could impact on their future therapeutic perspectives. PMID:26925287

  6. New stent delivery balloon: a technical note.

    PubMed

    di Mario, C; Reimers, B; Reinhardt, R; Ferraro, M; Moussa, I; Colombo, A

    1997-12-01

    This study reports the first clinical application of a new noncompliant balloon composed of a middle polyurethane layer sandwiched between an inner layer of polyethylene terephtalate and an outer membrane that provides for consistent even expansion. With this balloon design, the very low compliance and high pressure resistance of polyethylene terephthalate are associated with the high elasticity of polyurethane, preventing balloon damage from stent crimping and expansion and allowing a firm embedding of the stent struts. Palmaz-Schatz stent implantation was successful in 33/35 stents (94%), and the two stents that could not be advanced up to the lesion were successfully withdrawn. High pressure expansion of the stent was obtained during deployment with no balloon ruptures at inflation pressures equal or lower than 16 atmospheres (atm). Accurate positioning of the stent was facilitated by the two markers at the balloon ends and by the optimal visualization after contrast injection, even with 6 Fr guiding catheters. This new delivery system maintains the advantages of hand-crimped stents on noncompliant balloons, reducing the risk of stent loss. PMID:9408637

  7. Sex differences in long-term outcomes of coronary patients treated with drug-eluting stents at a tertiary medical center

    PubMed Central

    Shammas, Nicolas W; Shammas, Gail A; Jerin, Michael; Sharis, Peter

    2014-01-01

    Background Limited data exist on contemporary sex-related differences in long-term outcomes of coronary patients receiving drug-eluting stents. In this study we evaluate differences for males (M) and females (F) in 2-year target lesion failure (TLF) in an unselected consecutive series of patients treated with everolimus-eluting stents (EES) and paclitaxel-eluting stents (PES) at a tertiary medical center. Methods Data on 348 consecutive patients (M 221, F 127) stented with EES and PES were retrospectively analyzed. The primary end point of the study was to compare sex-related outcomes in TLF, defined as the combined end point of cardiac death, nonfatal myocardial infarction, and target lesion revascularization (TLR). Secondary end points included TLR, target vessel failure, target vessel revascularization, acute stent thrombosis as defined by the Academic Research Consortium, and cardiac death. The cineangiograms of the first consecutive 162 patients (M 105, F 57) were independently reviewed by a cardiologist blinded to clinical outcome, and SYNTAX scoring was performed. Follow-up was achieved using medical records and/or phone calls and was censored at 2 years. Descriptive analysis was performed on all variables. Univariate analysis compared the M and F cohorts. Multivariate analysis using Cox regression was performed to determine independent predictors of TLF with time, including sex as an independent variable in the model. Results M had more prior percutaneous coronary interventions and restenotic lesions and a higher prevalence of smoking. They also had longer length of disease and received more stents than F. F were older and had a higher prevalence of prior stroke. Angiographic complexity was not statistically different between the two groups, as judged by SYNTAX scoring (M 20.8±13.8, F 19.7±13.9, P=0.650). At 2-year follow-up, TLF was 27.4% and 24.8% (P=0.614) with no statistical difference between TLR (23.3% versus [vs] 21.6%), cardiac death (2.8% vs 3

  8. The effects of stent interaction on porcine urinary bladder matrix employed as stent-graft materials.

    PubMed

    Callanan, A; Davis, N F; McGloughlin, T M; Walsh, M T

    2014-06-01

    Deployment of stent-grafts, derived from synthetic biomaterials, is an established minimally invasive approach for effectively treating abdominal aortic aneurysms (AAAs). However, a notable disadvantage associated with this surgical technique is migration of the deployed stent-graft due to poor biocompatibility and inadequate integration in vivo. Recently, tissue-engineered extracellular matrices (ECMs) have shown early promise as integrating stabilisation collars in this setting due to their ability to induce a constructive tissue remodelling response after in vivo implantation. In the present study the effects of stent loading on an ECM׳s mechanical properties were investigated by characterising the compression and loading effects of endovascular stents on porcine urinary bladder matrix (UBM) scaffolds. Results demonstrated that the maximum stress was induced when the stent force was 8-times higher than a standard commercially available stent-graft and this represented about 20% of the failure strength of the UBM material. In addition, the influence of stent shape was also investigated. Findings demonstrated that the stress induced was higher for circular stents at low forces and a higher stress was induced on square stents when increased force was applied. Our findings demonstrate that porcine UBM possesses sufficient mechanical strength to withstand the compression and loading effects of commercially available stent-grafts in the setting of endovascular aneurysm repair.

  9. Successful stent implantation guided by intravascular ultrasound and a Doppler guidewire without contrast injection in a patient with allergy to iodinated contrast media.

    PubMed

    Okura, Hiroyuki; Nezuo, Shintaro; Yoshida, Kiyoshi

    2011-07-01

    Presence of allergy to iodinated contrast may prevent percutaneous coronary intervention (PCI) to be performed. We present a 76-year-old male with a history of allergic reaction to iodinated contrast who successfully underwent intravascular ultrasound (IVUS) and a Doppler guidewire-guided PCI. Stent size was determined based on IVUS. After PCI, stent expansion and a lack of edge dissection or incomplete apposition were confirmed by IVUS and a good antegrade coronary flow was confirmed by a Doppler guidewire. Thus, PCI without contrast injection under IVUS and a Doppler guidewire-guidance may be feasible in selected patients with allergy to iodinated contrast. PMID:21725127

  10. Electropolymerized tricopolymer based on N-pyrrole derivatives as a primer coating for improving the performance of a drug-eluting stent.

    PubMed

    Okner, Regina; Shaulov, Yulia; Tal, Noam; Favaro, Gregory; Domb, Abraham J; Mandler, Daniel

    2009-04-01

    The coating of medical implants by polymeric films aims at increasing their biocompatibility as well as providing a durable matrix for the controlled release of a drug. In many cases, the coating is divided into a primer layer, which bridges between the medical implant and the drug-eluting matrix. The primer coating must be very carefully designed in order to provide optimal interactions with the surface of the medical implant and the outer layer. Here we present a simple and versatile approach for designing the primer layer based on electropolymerization of a carefully chosen blend of three different pyrrole derivatives: N-methylpyrrole (N-me), N-(2-carboxyethyl)pyrrole (PPA), and the butyl ester of N-(2-carboxyethyl)pyrrole (BuOPy). The composition and physical properties of the primer layer were studied in detail by atomic force microscopy (AFM) and a nano scratch tester. The latter provides the in-depth analysis of the adhesion and viscoelasticity of the coating. AFM phase imaging reveals a uniform distribution of the three monomers forming rough morphology. This primer layer significantly improved the morphology, stability, and paclitaxel release profile of a paclitaxel-eluting matrix based on methyl and lauryl methacrylates.

  11. The Road to Bioabsorbable Stents: Reaching Clinical Reality?

    SciTech Connect

    Erne, Paul Schier, Matthias; Resink, Therese J.

    2006-02-15

    This article provides an overview of the evolution of revascularization devices since Gruentzig's initial introduction of balloon angioplasty in 1977. In-stent restenosis (ISR) is the major shortcoming of conventional (permanent-implant) stent therapy; even with the innovation and promising benefits of drug-eluting stents, management of ISR is very difficult. ISR is mainly caused by the interaction between the blood and the stent surface and a permanent mechanical irritation of the vascular tissue. Thus stenting technology has moved toward the development of temporary implants composed of biocompatible materials which mechanically support the vessel during the period of high risk for recoil and then completely biodegrade in the long term. Preclinical and first clinical experiences with bioabsorbable magnesium stents are discussed.

  12. Biomimicry, vascular restenosis and coronary stents.

    PubMed

    Schwartz, R S; van der Giessen, W J; Holmes, D R

    1998-01-01

    Biomimicry is in its earliest stages and is being considered in the realm of tissue engineering. If arterial implants are to limit neointimal thickening, purely passive structures cannot succeed. Bioactivity must be present, either by pharmacologic intervention or by fabricating a 'living stent' that contains active cellular material. As tissue engineering evolves, useful solutions will emerge from applying this knowledge directly to vascular biologic problems resulting from angioplasty, stenting, and vascular prosthesis research.

  13. Duration of Dual Antiplatelet Therapy After Drug-Eluting Stent Implantation in Patients With and Without Acute Coronary Syndrome: A Systematic Review of Randomized Controlled Trials.

    PubMed

    Sharma, Abhishek; Lavie, Carl J; Sharma, Samin K; Garg, Akash; Vallakati, Ajay; Mukherjee, Debabrata; Marmur, Jonathan D

    2016-08-01

    In this systemic review we evaluated the efficacy and safety of long duration dual anti-platelet therapy (DAPT) (L-DAPT) compared with short duration DAPT (S-DAPT) after drug-eluting stent (DES) implantation in patients who presented with or without acute coronary syndromes (ACS). We identified 8 randomized controlled trials in which 30,975 patients were randomized to S-DAPT versus L-DAPT (12,421 ACS and 18,554 non-ACS). Short duration dual anti-platelet therapy was associated with an increase in target vessel revascularization (TVR) in ACS patients, but the difference was not significant for non-ACS patients (odds ratio [OR] 5.04 [95% CI, 1.28-19.76], and OR, 0.89 [95% CI, 0.51-1.55], respectively). The risk of cardiac mortality was not significantly different with S-DAPT and L-DAPT for ACS (OR, 1.69 [95% CI, 0.82-3.50]) and non-ACS patients (OR, 0.89 [95% CI, 0.57-1.37]). For all cause mortality, myocardial infarction, and stent thrombosis, most of the events were derived from the DAPT study, thus a meta-analysis was not performed for these end points. Based on our review of the literature, we conclude that S-DAPT was associated with higher rates of stent thrombosis and myocardial infarction, and non-significant differences in all-cause mortality, with no significant interactions according to ACS vs non-ACS. However, in non-ACS patients, the benefit-risk profile favored S-DAPT, with lower all-cause mortality, whereas the trends were reversed in ACS. Additional studies are required to determine if the benefit-risk profile of S-DAPT vs L-DAPT varies according to clinical syndrome. PMID:27492914

  14. Virtual histology-intravascular ultrasound assessment of lesion coverage after angiographically-guided stent implantation in patients with ST Elevation myocardial infarction undergoing primary percutaneous coronary intervention.

    PubMed

    Legutko, Jacek; Jakala, Jacek; Mintz, Gary S; Wizimirski, Marcin; Rzeszutko, Lukasz; Partyka, Lukasz; Mrevlje, Blaz; Richter, Angela; Margolis, Pauliina; Kaluza, Grzegorz L; Dudek, Dariusz

    2012-05-15

    An occlusion or severe stenosis (angiographic culprit lesion) of the infarct-related artery is frequently located at the site of the maximum thrombus burden, whereas the origin of the plaque rupture (the true culprit) can be situated proximal or distal to it. The aim of this study was to examine stent coverage of true culprit lesions in 20 patients who underwent primary percutaneous coronary intervention and had Thrombolysis In Myocardial Infarction (TIMI) grade 3 flow restored in the infarct-related artery by angiographically guided direct stenting. Images of lesions were obtained using virtual histology-intravascular ultrasound before and after intervention (blinded to the operator). Plaque rupture sites were identified by intravascular ultrasound in 12 lesions (60%), 11 proximal and 1 distal to the minimum luminal area (MLA). Maximum necrotic core sites were found proximal to the MLA in 16 lesions, at the MLA in 3 lesions, and distal to the MLA in 1 lesion. Plaque rupture sites were fully covered by stents in 11 lesions. Virtual histology-intravascular ultrasound-derived thin-cap fibroatheroma longitudinal geographic misses were found in 10 lesions, 7 in the proximal reference segment and in 3 patients in the proximal and distal reference segments. In conclusion, in about 50% of patients who undergo primary percutaneous coronary intervention for ST-segment elevation myocardial infarction with optimal angiographic results, the stent does not fully cover the maximum necrotic core site related to the culprit lesion.

  15. Haemodynamic impact of stent-vessel (mal)apposition following carotid artery stenting: mind the gaps!

    PubMed

    De Santis, G; Conti, M; Trachet, B; De Schryver, T; De Beule, M; Degroote, J; Vierendeels, J; Auricchio, F; Segers, P; Verdonck, P; Verhegghe, B

    2013-01-01

    Carotid artery stenting (CAS) has emerged as a minimally invasive alternative to endarterectomy but its use in clinical treatment is limited due to the post-stenting complications. Haemodynamic actors, related to blood flow in the stented vessel, have been suggested to play a role in the endothelium response to stenting, including adverse reactions such as in-stent restenosis and late thrombosis. Accessing the flow-related shear forces acting on the endothelium in vivo requires space and time resolutions which are currently not achievable with non-invasive clinical imaging techniques but can be obtained from image-based computational analysis. In this study, we present a framework for accurate determination of the wall shear stress (WSS) in a mildly stenosed carotid artery after the implantation of a stent, resembling the commercially available Acculink (Abbott Laboratories, Abbott Park, Illinois, USA). Starting from angiographic CT images of the vessel lumen and a micro-CT scan of the stent, a finite element analysis is carried out in order to deploy the stent in the vessel, reproducing CAS in silico. Then, based on the post-stenting anatomy, the vessel is perfused using a set of boundary conditions: total pressure is applied at the inlet, and impedances that are assumed to be insensitive to the presence of the stent are imposed at the outlets. Evaluation of the CAS outcome from a geometrical and haemodynamic perspective shows the presence of atheroprone regions (low time-average WSS, high relative residence time) colocalised with stent malapposition and stent strut interconnections. Stent struts remain unapposed in the ostium of the external carotid artery disturbing the flow and generating abnormal shear forces, which could trigger thromboembolic events.

  16. Detection of thrombosis and restenosis in an endovascular stent

    NASA Astrophysics Data System (ADS)

    Wu, Junru; Weissman, Eric

    2002-05-01

    Endovascular stents that are implanted in an artery are often used in the interventional treatment of coronary artery disease. Its widespread applications are, however, limited by the development of subacute thrombosis (clot forming inside of the stent). Ex vivo experiments with pigs have shown that the broadband A-mode ultrasound is quite effective in detection thrombosis and restenosis in an endovascular stent. [Work supported by BFGoodrich and Noveon, Inc.

  17. Chemical etching of nitinol stents.

    PubMed

    Katona, Bálint; Bognár, Eszter; Berta, Balázs; Nagy, Péter; Hirschberg, Kristóf

    2013-01-01

    At present the main cause of death originates from cardiovascular diseases. Primarily the most frequent cause is vessel closing thus resulting in tissue damage. The stent can help to avoid this. It expands the narrowed vessel section and allows free blood flow. The good surface quality of stents is important. It also must have adequate mechanical characteristics or else it can be damaged which can easily lead to the fracture of the implant. Thus, we have to consider the importance of the surface treatment of these implants. In our experiments the appropriate design was cut from a 1.041 mm inner diameter and 0.100 mm wall thickness nitinol tube by using Nd:YAG laser device. Then, the stent was subjected to chemical etching. By doing so, the burr created during the laser cutting process can be removed and the surface quality refined. In our research, we changed the time of chemical etching and monitored the effects of this parameter. The differently etched stents were subjected to microscopic analysis, mass measurement and in vivo environment tests. The etching times that gave suitable surface and mechanical features were identified.

  18. Geometrical deployment for braided stent.

    PubMed

    Bouillot, Pierre; Brina, Olivier; Ouared, Rafik; Yilmaz, Hasan; Farhat, Mohamed; Erceg, Gorislav; Lovblad, Karl-Olof; Vargas, Maria Isabel; Kulcsar, Zsolt; Pereira, Vitor Mendes

    2016-05-01

    The prediction of flow diverter stent (FDS) implantation for the treatment of intracranial aneurysms (IAs) is being increasingly required for hemodynamic simulations and procedural planning. In this paper, a deployment model was developed based on geometrical properties of braided stents. The proposed mathematical description is first applied on idealized toroidal vessels demonstrating the stent shortening in curved vessels. It is subsequently generalized to patient specific vasculature predicting the position of the filaments along with the length and local porosity of the stent. In parallel, in-vitro and in-vivo FDS deployments were measured by contrast-enhanced cone beam CT (CBCT) in idealized and patient-specific geometries. These measurements showed a very good qualitative and quantitative agreement with the virtual deployments and provided experimental validations of the underlying geometrical assumptions. In particular, they highlighted the importance of the stent radius assessment in the accuracy of the deployment prediction. Thanks to its low computational cost, the proposed model is potentially implementable in clinical practice providing critical information for patient safety and treatment outcome assessment. PMID:26891065

  19. Recurrent coronary stent thromboses and myocardial infarctions.

    PubMed

    Chen, Jack; Rajeev, Angampally

    2007-11-01

    Although stent thrombosis is a recognized complication of coronary intervention, recurrent stent thrombosis is rarely reported. We present a patient who suffered 3 ST-segment elevation myocardial infarctions associated with repeated stent thromboses within a month and a half. Although a potentially mechanical cause of thrombosis was identified in the only baremetal stent implanted in this case, no predisposing factors were seen for the 2 drug-eluting stents (DES). While recent worrisome data have suggested a slight increase in the incidence of late angiographic stent thrombosis (defined as occurring beyond 30 days) with drug-eluting stents (DES), their risk of subacute thrombosis (from 1 to 30 days) is reported to be equivalent to that of BMS. Therefore, this rare occurrence serves as a sobering reminder of the risks of subacute thrombosis with both BMS and DES. Marked neointimal inhibition, allergic reactions, as well as thienopyridine resistance, may all contribute to the pathophysiology of DES thrombosis. The Food and Drug Administration advisory panel has concluded that when these devices are used for "on-label" indications, the counterbalance of dramatic target lesion revascularization reduction versus rare incidence of late angiographic stent thrombosis results in no overall increase in DES myocardial infarction or mortality risk. Furthermore, a minimum of 1 year of dual antiplatelet therapy is recommended for all recipients of DES at low risk of bleeding.

  20. Polymeric photosensitizer-embedded self-expanding metal stent for repeatable endoscopic photodynamic therapy of cholangiocarcinoma.

    PubMed

    Bae, Byoung-chan; Yang, Su-Geun; Jeong, Seok; Lee, Don Haeng; Na, Kun; Kim, Joon Mee; Costamagna, Guido; Kozarek, Richard A; Isayama, Hiroyuki; Deviere, Jacques; Seo, Dong Wan; Nageshwar Reddy, D

    2014-10-01

    Photodynamic therapy (PDT) is a new therapeutic approach for the palliative treatment of malignant bile duct obstruction. In this study, we designed photosensitizer-embedded self-expanding nonvascular metal stent (PDT-stent) which allows repeatable photodynamic treatment of cholangiocarcinoma without systemic injection of photosensitizer. Polymeric photosensitizer (pullulan acetate-conjugated pheophorbide A; PPA) was incorporated in self-expanding nonvascular metal stent. Residence of PPA in the stent was estimated in buffer solution and subcutaneous implantation on mouse. Photodynamic activity of PDT-stent was evaluated through laserexposure on stent-layered tumor cell lines, HCT-116 tumor-xenograft mouse models and endoscopic intervention of PDT-stent on bile duct of mini pigs. Photo-fluorescence imaging of the PDT-stent demonstrated homogeneous embedding of polymeric Pheo-A (PPA) on stent membrane. PDT-stent sustained its photodynamic activities at least for 2 month. And which implies repeatable endoscopic PDT is possible after stent emplacement. The PDT-stent after light exposure successfully generated cytotoxic singlet oxygen in the surrounding tissues, inducing apoptotic degradation of tumor cells and regression of xenograft tumors on mouse models. Endoscopic biliary in-stent photodynamic treatments on minipigs also suggested the potential efficacy of PDT-stent on cholangiocarcinoma. In vivo and in vitro studies revealed our PDT-stent, allows repeatable endoscopic biliary PDT, has the potential for the combination therapy (stent plus PDT) of cholangiocarcinoma.

  1. 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.

  2. Intraluminal Radioactive Stent Compared with Covered Stent Alone for the Treatment of Malignant Esophageal Stricture

    SciTech Connect

    Wang Zhongmin; Huang Xunbo; Cao Jun; Huang Gang; Chen Kemin LIu Yu; Liu Fenju

    2012-04-15

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

  3. Anatomy-shaped design of a fully-covered, biliary, self-expandable metal stent for treatment of benign distal biliary strictures

    PubMed Central

    Weigt, Jochen; Kandulski, Arne; Malfertheiner, Peter

    2016-01-01

    Background and study aims: The treatment success of benign biliary strictures with fully covered metal stents (CSEMS) is altered by high stent dislocation rates. We aimed to evaluate a new stent design to prevent dislocation. Patients and methods: Patients with benign biliary strictures were treated with a newly designed double-coned stent (dcSEMS). Mechanical analysis of the new stent was performed and it was compared with a cylindrical stent. Results: A total of 13 dcCSEMS were implanted in 11 patients (2 female, 9 male, median age 47, range 33 – 71). All patients had distal biliary strictures due to chronic pancreatitis. No stent migration occurred. In all but one patient the stents were removed. One patient refused stent extraction and was lost to follow up. Stent occlusion occurred twice leading to cholangitis in both cases. The duration of stent treatment was 170 days (range 61 – 254). After extraction only one patient had early recurrent stricture and received the same stent again. Three stents showed minimal tissue granulation at the papilla. One stent presented ingrowth at the proximal end and was removed after implantation of a second fully covered stent. Mechanical examination revealed significantly lower radial expansion force of the new stent as compared to the cylindrical stent. Conclusions: The new stent design has a low rate of migration. Biomechanical properties may explain this effect. PMID:26793789

  4. Ferromagnetic Bare Metal Stent for Endothelial Cell Capture and Retention.

    PubMed

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

    2015-01-01

    Rapid endothelialization of cardiovascular stents is needed to reduce stent thrombosis and to avoid anti-platelet therapy which can reduce bleeding risk. The feasibility of using magnetic forces to capture and retain endothelial outgrowth cells (EOC) labeled with super paramagnetic iron oxide nanoparticles (SPION) has been shown previously. But this technique requires the development of a mechanically functional stent from a magnetic and biocompatible material followed by in-vitro and in-vivo testing to prove rapid endothelialization. We developed a weakly ferromagnetic stent from 2205 duplex stainless steel using computer aided design (CAD) and its design was further refined using finite element analysis (FEA). The final design of the stent exhibited a principal strain below the fracture limit of the material during mechanical crimping and expansion. One hundred stents were manufactured and a subset of them was used for mechanical testing, retained magnetic field measurements, in-vitro cell capture studies, and in-vivo implantation studies. Ten stents were tested for deployment to verify if they sustained crimping and expansion cycle without failure. Another 10 stents were magnetized using a strong neodymium magnet and their retained magnetic field was measured. The stents showed that the retained magnetism was sufficient to capture SPION-labeled EOC in our in-vitro studies. SPION-labeled EOC capture and retention was verified in large animal models by implanting 1 magnetized stent and 1 non-magnetized control stent in each of 4 pigs. The stented arteries were explanted after 7 days and analyzed histologically. The weakly magnetic stents developed in this study were capable of attracting and retaining SPION-labeled endothelial cells which can promote rapid healing. PMID:26436434

  5. Ferromagnetic Bare Metal Stent for Endothelial Cell Capture and Retention.

    PubMed

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

    2015-01-01

    Rapid endothelialization of cardiovascular stents is needed to reduce stent thrombosis and to avoid anti-platelet therapy which can reduce bleeding risk. The feasibility of using magnetic forces to capture and retain endothelial outgrowth cells (EOC) labeled with super paramagnetic iron oxide nanoparticles (SPION) has been shown previously. But this technique requires the development of a mechanically functional stent from a magnetic and biocompatible material followed by in-vitro and in-vivo testing to prove rapid endothelialization. We developed a weakly ferromagnetic stent from 2205 duplex stainless steel using computer aided design (CAD) and its design was further refined using finite element analysis (FEA). The final design of the stent exhibited a principal strain below the fracture limit of the material during mechanical crimping and expansion. One hundred stents were manufactured and a subset of them was used for mechanical testing, retained magnetic field measurements, in-vitro cell capture studies, and in-vivo implantation studies. Ten stents were tested for deployment to verify if they sustained crimping and expansion cycle without failure. Another 10 stents were magnetized using a strong neodymium magnet and their retained magnetic field was measured. The stents showed that the retained magnetism was sufficient to capture SPION-labeled EOC in our in-vitro studies. SPION-labeled EOC capture and retention was verified in large animal models by implanting 1 magnetized stent and 1 non-magnetized control stent in each of 4 pigs. The stented arteries were explanted after 7 days and analyzed histologically. The weakly magnetic stents developed in this study were capable of attracting and retaining SPION-labeled endothelial cells which can promote rapid healing.

  6. 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.

  7. 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

  8. iStent trabecular micro-bypass stent for open-angle glaucoma.

    PubMed

    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.

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

    PubMed

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

    2014-12-20

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

  10. Very late in-stent thrombosis 9 years after double stent treatment of fusiform basilar artery aneurysm

    PubMed Central

    Juszkat, Robert; Stanislawska, Katarzyna; Jankowski, Roman; Liebert, Włodzimierz

    2015-01-01

    Endovascular treatment seems to be the best approach to posterior circulation fusiform aneurysms. Double stent techniques are frequently used to occlude basilar artery dilations. Unfortunately, there is a limited number of studies that have followed up with patients over prolonged periods of time in order to evaluate delayed complications, such as stenosis, thrombosis or migration of stents. We present an unusual case of in-stent thrombosis 9 years after basilar artery aneurysm treatment to caution about complications associated with double stent implantation. PMID:25964437

  11. Metallic stents in malignant biliary obstruction

    SciTech Connect

    Rieber, Andrea; Brambs, Hans-Juergen

    1997-01-15

    Purpose. Retrospective analysis of our results with metallic stent placement for malignant biliary strictures. We sought to determine parameters that influence stent patency. Methods. A total of 95 Wallstents were implanted in 65 patients (38 men, 27 women; mean age, 65.1 years) with malignant biliary obstruction. Serum bilirubin levels were assessed in 48 patients; the mean value prior to intervention was 15.0 mg/dl. Results. In 12 patients (21%) complications occurred as a result of percutaneous transhepatic drainage. Stent implantation was complicated in 13 patients, but was possible in all patients. A significant decrease in bilirubin level was seen in 83.3% of patients following stent implantation. Approximately 30% of patients developed recurrent jaundice after a mean 97.1 days. In 9 patients (15%) the recurrent jaundice was caused by stent occlusion due to tumor growth. The mean follow-up was 141.8 days, the mean survival 118.7 days. Patients with cholangiocarcinomas and gallbladder carcinomas had the best results. Worse results were seen in patients with pancreatic tumors and with lymph node metastases of colon and gastric cancers. Conclusions. The main predictive factors for occlusion rate and survival are the type of primary tumor, tumor stage, the decrease in bilirubin level, and the general condition of the patient.

  12. Vessel healings after stenting with different polymers in STEMI patients

    PubMed Central

    Jin, Qin-Hua; Chen, Yun-Dai; Tian, Feng; Guo, Jun; Jing, Jing; Sun, Zhi-Jun

    2016-01-01

    Background Different stents implantation in ST-segment elevation myocardial infarction (STEMI) patients may influence the long term prognosis by affecting vessel healings after stenting. The aim of this study was to evaluate the vessel healings after implantation of drug eluting stents (DES) with biodegradable or durable polymer or of bare-metal stents (BMS) in patients with acute STEMI. Methods This study included 50 patients, who underwent follow up angiogram and optical coherence tomography (OCT) assessment about one year after percutaneous coronary intervention (PCI) for STEMI. According to the initial stents types, these patients were classified to durable (n = 19) or biodegradable polymer sirolimus-eluting stents (n = 15), or BMS (n = 16) groups. The conditions of stent struts coverage and malapposition were analyzed with OCT technique. Results A total of 9003 struts were analyzed: 3299, 3202 and 2502 from durable or biodegradable polymer DES, or BMS, respectively. Strut coverage rate (89.0%, 94.9% and 99.3%, respectively), malapposition presence (1.7%, 0.03% and 0 of struts, respectively) and average intimal thickness over struts (76 ± 12 µm, 161 ± 30 µm and 292 ± 29 µm, respectively) were significantly different among different stent groups (all P < 0.001). Conclusions Vessel healing status in STEMI patients is superior after implantation of biodegradable polymer DES than durable polymer DES, while both are inferior to BMS. PMID:27403139

  13. Endophthalmitis associated with Glaucoma Shunt Intraluminal Stent Exposure.

    PubMed

    Kwon, Hye Jin; Kerr, Nathan M; Ruddle, Jonathan B; Ang, Ghee Soon

    2016-01-01

    Endophthalmitis post glaucoma drainage implant (GDI) surgery is rare, often associated with tube or plate exposure. We report a case of endophthalmitis following glaucoma shunt intraluminal stent exposure in a patient who underwent Baerveldt glaucoma implant surgery. Endophthalmitis following manipulation of intraluminal stents is a rare complication of GDIs but potentially vision threatening condition that needs to be carefully screened for and treated immediately. How to cite this article: Kwon HJ, Kerr NM, Ruddle JB, Ang GS. Endophthalmitis associated with Glaucoma Shunt Intraluminal Stent Exposure. J Curr Glaucoma Pract 2016;10(1):36-37.

  14. First-Generation Versus Second-Generation Drug-Eluting Stents in Coronary Chronic Total Occlusions: Two-Year Results of a Multicenter Registry

    PubMed Central

    Yu, Cheol Woong; Kim, Je Sang; Lee, Hyun Jong; Choi, Rak Kyeong; Kim, Tae Hoon; Jang, Ho Joon; Choi, Young Jin; Roh, Young Moo; Shim, Won-Heum; Song, Young Bin; Hahn, Joo-Yong; Choi, Jin-Ho; Lee, Sang Hoon; Gwon, Hyeon-Cheol; Choi, Seung-Hyuk

    2016-01-01

    Background Limited data are available regarding the long-term clinical outcomes of second-generation drug-eluting stents (DES) versus first-generation DES in patients with coronary chronic total occlusion (CTO) who undergo percutaneous coronary intervention (PCI). The aim of this study was to compare the clinical outcomes of second-generation DES with those of first-generation DES for the treatment of CTO. Methods and Results Between March 2003 and February 2012, 1,006 consecutive patients with CTO who underwent successful PCI using either first-generation DES (n = 557) or second-generation DES (n = 449) were enrolled in a multicenter, observational registry. Propensity-score matching was also performed. The primary outcome was cardiac death over a 2-year follow-up period. No significant differences were observed between the two groups regarding the incidence of cardiac death (first-generation DES versus second-generation DES; 2.5% vs 2.0%; hazard ratio [HR]: 0.86; 95% confidence interval [CI]: 0.37 to 1.98; p = 0.72) or major adverse cardiac events (MACE, 11.8% vs 11.4%; HR: 1.00; 95% CI: 0.67 to 1.50; p = 0.99). After propensity score matching, the incidences of cardiac death (HR: 0.86; 95% CI: 0.35 to 2.06; p = 0.86) and MACE (HR: 0.93; 95% CI: 0.63 to 1.37; p = 0.71) were still similar in both groups. Furthermore, no significant differences were observed between sirolimus-eluting, paclitaxel-eluting, zotarolimus-eluting, and everolimus-eluting stents regarding the incidence of cardiac death or MACE. Conclusion This study shows that the efficacy of second-generation DES is comparable to that of first-generation DES for treatment of CTO over 2 years of follow-up. PMID:27314589

  15. A review on biodegradable materials for cardiovascular stent application

    NASA Astrophysics Data System (ADS)

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

    2016-09-01

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

  16. In vivo and protease-activated receptor-1-mediated platelet activation but not response to antiplatelet therapy predict two-year outcomes after peripheral angioplasty with stent implantation.

    PubMed

    Gremmel, T; Steiner, S; Seidinger, D; Koppensteiner, R; Panzer, S; Kopp, C W

    2014-03-01

    Data linking the response to antiplatelet therapy with clinical outcomes after angioplasty and stenting for lower extremity artery disease (LEAD) are scarce. Moreover, associations of in vivo and thrombin-inducible platelet activation with the occurrence of adverse events have not been investigated in these patients, so far. We therefore assessed clinical outcomes and on-treatment platelet reactivity by four test systems in 108 patients receiving dual antiplatelet therapy after infrainguinal angioplasty and stenting for LEAD. Further, in vivo and thrombin receptor-activating peptide (TRAP)-6-inducible glycoprotein (GP) IIb/IIIa activation and P-selectin expression were measured as sensitive parameters of platelet activation. The primary endpoint was defined as the composite of atherothrombotic events and target vessel restenosis or reocclusion. Residual platelet reactivity to adenosine diphosphate and arachidonic acid was similar between patients without and with adverse outcomes within two-year follow-up (all p>0.05). Further, the occurrence of clinical endpoints did not differ significantly between patients without and with high on-treatment residual platelet reactivity by all test systems (all p>0.05). In contrast, in vivo and TRAP-6-inducible platelet activation were significantly more pronounced in patients with subsequent adverse events (all p<0.05), and high levels of platelet activation were independent predictors of the primary endpoint (adjusted hazard ratios: 3.5 for high in vivo activated GPIIb/IIIa, 2.9 for high TRAP-6-inducible activated GPIIb/IIIa, 2.3 for high in vivo P-selectin, and 3 for high TRAP-6-inducible P-selectin; all p<0.05). In conclusion, in vivo and protease-activated receptor-1-mediated platelet activation predict two-year clinical outcomes in stable patients undergoing angioplasty and stenting for LEAD.

  17. Endovascular Stenting for Unsuccessful Angioplasty of the Aorta in Aortoarteritis

    SciTech Connect

    Tyagi, Sanjay; Kaul, Upkar A.; Arora, Ramesh

    1999-11-15

    Purpose: The efficacy and safety of endovascular stent implantation to correct dissection or a suboptimal result after percutaneous transluminal angioplasty (PTA) was evaluated in patients suffering from aortic stenosis due to aortoarteritis. Methods: Twelve children and young adults [aged (mean {+-} SD) 18.2 {+-} 8.7 years] underwent stent implantation after PTA of the aorta, seven for obstructive dissection, four for ineffective balloon dilatation, and one for recurrent restenosis. Nine patients underwent implantation of self-expandable stents and three received balloon-expandable Palmaz stents. Results: Stent implantation could be successfully performed in all 12 patients. After stent implantation, the peak systolic pressure gradient decreased from 91 {+-} 33.5 mmHg to 12.4 {+-} 12.5 mmHg (p < 0.001). The diameter of the stenosed segment increased from 4.6 {+-} 0.8 mm to 11.1 {+-} 1.9 mm (p < 0.001). The dissection was completely covered in all seven patients with dissection. Except for epigastric pain with vomiting in one patient, there was no complication. On follow-up, over 12-57 months (mean 26.8 {+-} 10.8 months), 11 patients (91.6%) had marked improvement in their blood pressure. Patients with congestive heart failure and claudication also showed improvement. Repeat catheterization in five patients, between 6-30 months (mean 16.8 {+-} 9.1 months) after stent implantation, showed sustained improvement in four and a fusiform, long segment, intrastent restenosis after 30 months in one child. The stenosis was safely redilated. Conclusion: Endovascular aortic stent implantation is safe and provides good immediate relief in patients with unsatisfactory results after balloon angioplasty. Improvement is sustained in most patients on intermediate-term follow-up.

  18. Introduction of a high-throughput double-stent animal model for the evaluation of biodegradable vascular stents.

    PubMed

    Borinski, Mauricio; Flege, Christian; Schreiber, Fabian; Krott, Nicole; Gries, Thomas; Liehn, Elisa; Blindt, Rüdiger; Marx, Nikolaus; Vogt, Felix

    2012-11-01

    Current stent system efficacy for the treatment of coronary artery disease is hampered by in-stent restenosis (ISR) rates of up to 20% in certain high-risk settings and by the risk of stent thrombosis, which is characterized by a high mortality rate. In theory, biodegradable vascular devices exhibit crucial advantages. Most absorbable implant materials are based on poly-L-lactic acid (PLLA) owing to its mechanical properties; however, PLLA might induce an inflammatory reaction in the vessel wall. Evaluation of biodegradable implant efficacy includes a long-term examination of tissue response; therefore, a simple in vivo tool for thorough biocompatibility and biodegradation evaluation would facilitate future stent system development. Rats have been used for the study of in vivo degradation processes, and stent implantation into the abdominal aorta of rats is a proven model for stent evaluation. Here, we report the transformation of the porcine double-stent animal model into the high-throughput rat abdominal aorta model. As genetic manipulation of rats was introduced recently, this novel method presents a powerful tool for future in vivo biodegradable candidate stent biocompatibility and biodegradation characterization in a reliable simple model of coronary ISR.

  19. Stent Graft-in-Stent Graft as a Rescue Technique for Endovascular Treatment of Giant Extracranial Internal Carotid Aneurysm

    PubMed Central

    Jeha, Salim Abdon Haber

    2016-01-01

    Endovascular treatment of a giant extracranial internal carotid aneurysm by a stent graft implantation was unsuccessful due to a high flow leak directly through the stent graft's coating. The problem was solved deploying a second stent graft inside the previously implanted one resulting in complete exclusion of the aneurysmal sac and patent carotid lumen preservation. The review of the literature did not provide a case using this endovascular strategy. Follow-up for more than 12 months, using CT angiography, showed confirmed aneurysmal exclusion and carotid patency and no clinical complications have been detected. PMID:27752387

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

    SciTech Connect

    Zelenak, Kamil; Zelenakova, Jana; DeRiggo, Julius; Kurca, Egon; Boudny, Jaroslav; Polacek, Hubert

    2011-12-15

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

  1. Comparison of neointimal morphology of in-stent restenosis with sirolimus-eluting stents versus bare metal stents: virtual histology-intravascular ultrasound analysis.

    PubMed

    Yamamoto, Yoshihiro; Otani, Hajime; Iwasaka, Junji; Park, Haengnam; Sakuma, Takao; Kamihata, Hiroshi; Iwasaka, Toshiji

    2011-09-01

    Sirolimus-eluting stents (SES) have reduced the incidence of restenosis and target lesion revascularization compared to bare metal stents (BMS). However, inhibition of endothelialization and neointimal formation after SES implantation may produce vulnerable plaques. The present study compared the neointimal morphology of in-stent restenosis (ISR) between SES and BMS using virtual histology-intravascular ultrasound (VH-IVUS). Thirty ISR lesions (SES n = 15, BMS n = 15) demonstrated by coronary angiography in 30 patients with stable angina pectoris were analyzed with VH-IVUS between 6 months to 3 years after stent implantation. Tissue maps were reconstructed from radiofrequency data using VH-IVUS software. ISR lesions after SES implantation consisted of a significantly increased necrotic core (NC) compared to BMS (12.9 vs. 5.6% of neointimal volume, p < 0.01). However, the NC in ISR lesions after SES implantation was covered with a thick fibrous cap. An increase in the size of NC covered with a thick fibrous cap is a characteristic morphological feature of ISR after SES implantation. Further studies are needed to clarify whether such a morphological change is related to the attenuation of stent thrombosis after SES implantation.

  2. Stent thrombosis: incidence and related factors in the R.I.S.E. Registry(Registro Impianto Stent Endocoronarico)

    PubMed

    De Servi, S; Repetto, S; Klugmann, S; Bossi, I; Colombo, A; Piva, R; Giommi, L; Bartorelli, A; Fontanelli, A; Mariani, G; Klersy, C

    1999-01-01

    Although stent thrombosis has been greatly reduced by adequate stent expansion with high-pressure balloon inflations and by the use of antiplatelet drugs, this event is still frightening, as it may lead to acute myocardial ischemia resulting in acute myocardial infarction or sudden death. Therefore, the definition of factors associated with stent thrombosis may provide a better understanding of the mechanisms underlying this phenomenon and may permit us to define therapeutic strategies to further reduce its occurrence. The purpose of this study was to assess factors responsible for the occurrence of stent thrombosis after coronary stent implantation in 939 consecutive patients enrolled in the Registro Impianto Stent Endocoronarico (R.I.S.E. Study Group). Consecutive patients undergoing coronary stent implantation at 16 medical centers in Italy were prospectively enrolled in the registry. Clinical data, and qualitative and quantitative angiographic findings were obtained from data collected in case report forms at each investigator site. The study group consisted of 781 men and 158 women with a mean age of 59 yr: 1,392 stents were implanted in 1,006 lesions and expanded at a maximal inflation pressure of 14.7 +/- 3 atm. The great majority of patients (92%) received only antiplatelet drugs after coronary stenting. During hospitalization there were 45 major ischemic complications in 39 patients (4.2%): 13 events were related to acute or subacute thrombosis (1.4%). Another stent thrombotic event occurred in the first month of follow-up. On multivariate logistic regression analysis, stent thrombosis was related to the following factors: unplanned stenting (OR 3.46, 95% CI 1.65-7.23), unstable angina (OR 3.37, 95% CI 1.11-10.14) and maximal inflation pressure (OR 0.83, 95% CI 0.75-0.93). In conclusion, this registry shows that in an unselected population of patients undergoing coronary stenting, stent thrombosis occurs in less than 2% of patients and is significantly

  3. Temporary Strecker Stent for Management of Acute Dissection in Popliteal and Crural Arteries

    SciTech Connect

    Manke, Christoph; Geissler, Angela; Seitz, Johannes; Lenhart, Markus; Kasprzak, Piotr; Gmeinwieser, Josef; Feuerbach, Stefan

    1999-03-15

    Stent placement is a widely used bail-out treatment for dissection of peripheral arteries. Below the level of the superficial femoral artery permanent stenting is complicated by a high incidence of subacute thrombosis and restenosis. We present two cases of arterial occlusion due to acute iatrogenic dissection of the popliteal and distal fibular arteries. Successful treatment was achieved with a new bail-out procedure. Strecker stents were implanted to seal off the dissection flap. Stents were retrieved easily after 24 hr using a myocardial biopsy forceps. After stent retrieval the temporarily stented segments were patent and showed a larger lumen compared with segments treated by balloon dilatation alone. Temporary stenting is a simple and safe procedure and offers the advantage of tacking up dissection membranes and preventing recoil. Persistent presence of a metallic implant as a source of continued injury and stimulus for intimal proliferation is avoided.

  4. Single and Tandem Stents in Sheep Iliac Arteries: Is There a Difference in Patency?

    SciTech Connect

    Schuermann, Karl; Vorwerk, Dierk; Buecker, Arno; Grosskortenhaus, Stefanie; Guenther, Rolf W.

    1998-09-15

    Purpose: To compare patency and neointima formation of single and tandem arterial stents. Methods: In each of six sheep, two Memotherm nitinol stents (tandem stents) were inserted into the external iliac artery on one side and a single stent into the artery on the opposite side. The size of the iliac lumen was assessed in the proximal, middle, and distal segments of the stents by intravascular ultrasound (IVUS) before, immediately after, and 1 month after implantation when the sheep were killed. Neointimal thickness was determined in the proximal, middle, and distal segments of each stent by light microscopy. Results: All stents remained patent. There was no significant difference in lumen and neointimal thickness between single and tandem stents. Cranial tandem stents showed a significantly wider lumen and smaller neointimal thickness than caudal tandem stents. In the proximal and distal segments, the lumen of the stents was significantly smaller and the neointimal thickness greater than in the middle segment; differences in neointimal thickness were significant only between the proximal and the middle segment. Conclusion: In an experimental setting, tandem stents did not interfere with one another with regard to patency and neointima formation when compared with a single contralateral stent. Neointimal thickening after stent insertion seems to be inversely related to the original arterial diameter.

  5. Subacute stent thrombosis and the anticoagulation controversy: changes in drug therapy, operator technique, and the impact of intravascular ultrasound.

    PubMed

    Moussa, I; Di Mario, C; Di Francesco, L; Reimers, B; Blengino, S; Colombo, A

    1996-08-14

    Clinical trials have shown that stents are superior to other catheter-based coronary interventions in terms of reduced complications and improved long-term efficacy. With utilization of high-pressure balloon inflation and intravascular ultrasound (IVUS) guidance, stent implantation can now be performed safely without anticoagulation (i.e., with lower rates of stent thrombosis and vascular complications). In 2 recent prospective clinical trials, stent thrombosis occurred in 3.5% of cases despite anticoagulant therapy, which resulted in an average of 7% vascular and bleeding complications. Initial use of IVUS during traditional stent deployment showed that 80% of stents were underexpanded and led to the hypothesis that stent thrombosis might be decreased as a result of optimal stent placement under IVUS guidance without the need for anticoagulation. In a prospective clinical trial to test this hypothesis, three factors were found to reduce stent thrombosis: full stent expansion, complete apposition to the vessel wall, and full lesion coverage. Predictors of thrombotic risk in this era of high-pressure stent deployment without anticoagulation include low ejection fraction, residual dissections, slow flow, multiple stents per lesion, and smaller postprocedure stent luminal diameter. To optimize stent expansion, stent dilation should be performed using a mean inflation pressure of 18 atm with a noncompliant or minimally compliant balloon sized to the vessel being treated (B/V ratio = 1.1). Controversy still remains about the best poststent antiplatelet regimen, and results of a recent trial should indicate whether heparin coating provides additional protection from stent thrombosis.

  6. Percutaneous Endoluminal Stent and Stent-Graft Placement for the Treatment of Femoropopliteal Aneurysms: Early Experience

    SciTech Connect

    Mueller-Huelsbeck, Stefan; Link, Johann; Schwarzenberg, Helmut; Walluscheck, Knut P.; Heller, Martin

    1999-03-15

    Purpose: To determine the efficacy of percutaneous endoluminal stents and stent-grafts for the treatment of isolated femoropopliteal aneurysms. Methods: Seven men (age 51-69 years) with femoropopliteal occlusions (n= 6) related to aneurysms and a patent femoropopliteal aneurysm (n= 1) were treated percutaneously. In two patients uncovered Wallstents and in five patients polyester-covered nitinol stents were implanted. Assessment was performed with Doppler ultrasound and duplex ultrasonography 24 hr, 1, 3, 6, 12, and 24 months after the intervention. Additionally, intraarterial angiography was performed at 6 months. Results: Stent placement succeeded in all cases. No immediate adjunctive surgical treatment was necessary. Ankle-brachial index (ABI) improved from 0.29 {+-} 0.29 (SD) before to 0.78 {+-} 0.23 (SD) 24 hr after the intervention. One patient was lost to follow-up. Stent-graft occlusion occurred in four patients: after 2 days (n1), 1 month (n= 2), and 3 months (n= 1). One of the patients, whose stent occluded at 1 month, underwent successful recanalization with local fibrinolysis therapy. Three of the seven, all with three-vessel run-off, demonstrated patency of the stent, which was assessed by duplex ultrasonography at 29, 31, and 34 months. Breaking of the stent struts or significant stent migration was not observed. Conclusions: These results in a small number of patients warrant further investigation to evaluate the role of percutaneous stents in femoropopliteal aneurysms. Until further data of clinical studies are available, this method cannot be recommended, and it cannot replace surgical treatment.

  7. Biodegradable Metals for Cardiovascular Stent Application: Interests and New Opportunities

    PubMed Central

    Moravej, Maryam; Mantovani, Diego

    2011-01-01

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

  8. Biodegradable metals for cardiovascular stent application: interests and new opportunities.

    PubMed

    Moravej, Maryam; Mantovani, Diego

    2011-01-01

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

  9. Preprocedural Albumin Levels and Risk of In-Stent Restenosis After Coronary Stenting With Bare-Metal Stent.

    PubMed

    Celik, Ibrahim Etem; Yarlioglues, Mikail; Kurtul, Alparslan; Duran, Mustafa; Koseoglu, Cemal; Oksuz, Fatih; Aksoy, Ozlem; Murat, Sani Namik

    2016-05-01

    In-stent restenosis (ISR) remains a significant clinical problem in patients with coronary artery disease treated with percutaneous coronary intervention. Decreased serum albumin (SA) level is related to an increased risk of cardiovascular events. The aim of the present study was to assess whether SA levels at admission are an independent predictor of ISR in patients undergoing bare-metal stent (BMS) implantation. A total of 341 patients (aged 61 ± 11, 65.4% men) with a history of BMS implantation and a further control coronary angiography due to stable angina pectoris (SAP) were included. The study population was classified into 2 groups: patients with and without ISR. The ISR was observed in 140 (41.1%) patients. We found significantly lower SA levels in patients who developed ISR than in those who did not (3.69 ± 0.41 vs 4.07 ± 0.35 mg/dL,P< .001). Multivariate analysis revealed that SA level (odds ratio 0.109, 95% confidence interval 0.017-0.700,P= .020), stent diameter, reason for stent implantation, and body mass index were independent risk factors for the development of ISR. The SA level at admission is inversely associated with ISR in patients with SAP.

  10. Recent Advances in Drug Eluting Stents

    PubMed Central

    Puranik, Amey S.; Dawson, Eileen R.; Peppas, Nicholas A.

    2013-01-01

    One of the most common medical interventions to reopen an occluded vessel is the implantation of a coronary stent. While this method of treatment is effective initially, restenosis, or the re-narrowing of the artery frequently occurs largely due to neointimal hyperplasia of smooth muscle cells. Drug eluting stents were developed in order to provide local, site-specific, controlled release of drugs that can inhibit neointima formation. By implementing a controlled release delivery system it may be possible to control the time release of the pharmacological factors and thus be able to bypass some of the critical events associated with stent hyperplasia and prevent the need for subsequent intervention. However, since the advent of first-generation drug eluting stents, long-term adverse effects have raised concerns regarding their safety. These limitations in safety and efficacy have triggered considerable research in developing biodegradable stents and more potent drug delivery systems. In this review, we shed light on the current state-of-the-art in drug eluting stents, problems related to them and highlight some of the ongoing research in this area. PMID:23117022

  11. Impact of stent length on clinical outcomes of first-generation and new-generation drug-eluting stents.

    PubMed

    Konishi, Hirokazu; Miyauchi, Katsumi; Dohi, Tomotaka; Tsuboi, Shuta; Ogita, Manabu; Naito, Ryo; Kasai, Takatoshi; Tamura, Hiroshi; Okazaki, Shinya; Isoda, Kikuo; Daida, Hiroyuki

    2016-04-01

    The aim of this study is to compare first- and new-generation drug-eluting stents (DESs) which are implanted in long lesion. Stent length is known to be a predictor of adverse events after percutaneous coronary intervention (PCI), even with the first-generation DESs. The introduction of new-generation DESs has reduced the rates of adverse clinical events. However, the impact of stent length on long-term clinical outcomes is not well known. A total of 1181 consecutive patients who underwent PCI using either a first-generation DES (n = 885) or a new-generation DES (n = 296) between 2004 and 2011 were investigated. In each of the stent groups, the patients were divided into two groups by stent length (>32 and ≤32 mm) and compared. During the follow-up period, the incidence of major adverse cardiac events (MACEs) was significantly higher for patients with long stents implanted than with short stents (P < 0.01; log-rank test) in the first-generation DES group. However, there was no difference in the incidence of MACEs between the long- and short-stent groups in the new-generation DES group (P = 0.24; log-rank test). On multivariate Cox regression analysis, stent length was not associated with adverse events in the new-generation DES groups [hazard ratio (HR) 0.87; 95 % confidence interval (95 % CI) 0.71-1.04; P = 0.14]. Implanted stent length was significantly associated with a higher risk of MACEs in patients who received first-generation DESs, but not in patients who received the new-generation DESs.

  12. Coronary Stent Thrombosis: Current Insights into New Drug-Eluting Stent Designs

    PubMed Central

    Kim, Hyun Kuk

    2012-01-01

    The advances of interventional cardiology have been achieved by new device development, finding appropriate drug regimes, and understanding of pathomechanism. Drug-eluting stents (DES) implantation with dual anti-platelet therapy reduced revascularization without increasing mortality or myocardial infarction compared with bare-metal stenting. However, late-term stent thrombosis (ST) and restenosis limited its value and raised the safety concern. Main mechanisms of this phenomenon are impaired endothelialization and hypersensitivity reaction with polymer. The second generation DES further improved safety and/or efficacy by using thinner stent strut and biocompatible polymer. Recently, new concept DES with biodegradable polymer, polymer-free and bioabsorbable scaffold are under investigation in the quest to minimize the risk of ST. PMID:23323218

  13. Biomechanical Challenges to Polymeric Biodegradable Stents.

    PubMed

    Soares, Joao S; Moore, James E

    2016-02-01

    Biodegradable implants have demonstrated clinical success in simple applications (e.g., absorbable sutures) and have shown great potential in many other areas of interventional medicine, such as localized drug delivery, engineered tissue scaffolding, and structural implants. For endovascular stenting and musculoskeletal applications, they can serve as temporary mechanical support that provides a smooth stress-transfer from the degradable implant to the healing tissue. However, for more complex device geometries, in vivo environments, and evolving load-bearing functions, such as required for vascular stents, there are considerable challenges associated with the use of biodegradable materials. A biodegradable stent must restore blood flow and provide support for a predictable appropriate period to facilitate artery healing, and subsequently, fail safely and be absorbed in a controllable manner. Biodegradable polymers are typically weaker than metals currently employed to construct stents, so it is difficult to ensure sufficient strength to keep the artery open and alleviate symptoms acutely while keeping other design parameters within clinically acceptable ranges. These design challenges are serious, given the general lack of understanding of biodegradable polymer behavior and evolution in intimal operating conditions. The modus operandi is mainly empirical and relies heavily on trial-and-error methodologies burdened by difficult, resource-expensive, and time-consuming experiments. We are striving for theoretical advancements systematizing the empirical knowledge into rational frameworks that could be cast into in silico tools for simulation and product development optimization. These challenges are evident when one considers that there are no biodegradable stents on the US market despite more than 30 years of development efforts (and currently only a couple with CE mark). This review summarizes previous efforts at implementing biodegradable stents, discusses the

  14. In Vitro Comparison of Self-Expanding Versus Balloon-Expandable Stents in a Human Ex Vivo Model

    SciTech Connect

    Grenacher, Lars Rohde, Stefan Gaenger, Ellen; Deutsch, Jochen; Kauffmann, Guenter W.; Richter, Goetz M.

    2006-04-15

    The objective was to compare the radial strength and expansile precision of self-expanding stents and balloon-expandable stents in a human cadaver bifurcation model. Seven different self-expanding (LUMINEXX, JOSTENT SelfX, JOSTENT SelfX hrf, Sinus-Repo, Sinus SuperFlex, Easy Wallstent, SMART) and four different balloon-expandable stent models (Palmaz, Sinus Stent, SAXX Medium, JOSTENT peripheral), each type 10 stents (total n = 110 stents) were implanted into the common iliac arteries of human cadaver corpses. The maximum stent diameter was 10 mm for all models. After stent implantation, the specimens were filled with silicone caoutchouc. After 24 h, the vascular walls including the stents were removed from the hardened casts. Diameters were taken and the weight of the cast cylinders was measured in air and in purified water to calculate the volume of the bodies (according to Archimedes Law) as a relative but precise degree for the radial strength of the implanted stents. The cylindrical casts of the self-expanding stents showed lower mean diameters (8.2 {+-} 1.0 mm) and mean volumes (0.60 {+-} 0.14 ml/cm) than in the balloon-expandable stent group (10.1 {+-} 0.3 mm and 0.71 {+-} 0.04 ml/cm, respectively; p < 0.01). The nominal maximum diameter of 10 mm was not achieved in any of the self-expanding stents, but this was achieved in more than 70% (29/40) of the balloon-expandable stent specimens (p < 0.05). The variation between achieved volumes was significantly larger in self-expanding (range: 0.23-0.78 ml/cm) than in balloon-expandable stents (range: 0.66-0.81 ml/cm; p < 0.05). Self-expanding stents presented considerably lower radial expansion force and lower degree of precision than balloon-expandable stents.

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

    SciTech Connect

    Cerna, Marie; Koecher, Martin Valek, Vlastimil; Aujesky, Rene; Neoral, Cestmir; Andrasina, Tomas; Panek, Jiri; Mahathmakanthi, Shankari

    2011-12-15

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

  16. Relation of genetic polymorphisms in the cytochrome P450 gene with clopidogrel resistance after drug-eluting stent implantation in Koreans.

    PubMed

    Lee, Jung Myung; Park, Sungha; Shin, Dong-Jik; Choi, Donghoon; Shim, Chi Young; Ko, Young-Guk; Kim, Jung-Sun; Shin, Eun-Soon; Chang, Chong Won; Lee, Jong-Eun; Jang, Yangsoo

    2009-07-01

    Clopidogrel is a prodrug that has to be converted to an active metabolite by hepatic cytochrome P450 (CYP) isoenzymes to inhibit platelet aggregation. Individual variability of platelet inhibition by clopidogrel suggests a possibility for genetic factors having a significant influence on clopidogrel responsiveness. In this study, we sought to determine the relation of genetic polymorphisms of CYP genes to clopidogrel resistance in Koreans. Four hundred fifty patients who underwent successful percutaneous coronary intervention with drug-eluting stents were randomly assigned to treatment with dual antiplatelet regimen (aspirin plus clopidogrel) or triple antiplatelet regimen (aspirin plus clopidogrel plus cilostazol). Clopidogrel resistance using VerifyNow P2Y12 assay and genetic analysis were performed in 387 patients. Clopidogrel resistance was found in 112 patients (28.9%). In the clopidogrel-responsive group, there was a significantly higher proportion of cilostazol use. Because cilostazol showed a significant influence on clopidogrel resistance, we examined the association of single-nucleotide polymorphisms and clopidogrel resistance in the dual and triple antiplatelet therapy groups, respectively. In all subjects, the CYP2C19*3A allele was significantly more prevalent in the clopidogrel-resistant group compared with the clopidogrel-responsive group. Multiple logistic regression analysis demonstrated that CYP2C19*3 is an independent predictor of clopidogrel resistance. In conclusion, CYP2C19*3 single-nucleotide polymorphisms is an independent risk factor of clopidogrel resistance in Korean subjects with coronary artery disease. PMID:19576320

  17. [Stent, endovascular prosthesis, net or strut? What would British dentist Charles Stent (1807-1885) have to say on all this?].

    PubMed

    Lukenda, Josip; Biocina-Lukenda, Dolores

    2009-01-01

    The word stent appears in the Index Medicus as of 1952, while in Croatian articles as of 1993. The origin of the word has been attributed to British dentist Charles. T. Stent (1807-1885), maker of the compound for dental impressions (Stent's compound). Viennese surgeon, Johannes F. S. Esser (1877-1946) used the compound in plastic surgery of the face calling it an eponym Stent's mould. During the 1950's, William H. ReMine and John H. Grindlay used Stent's principle for omentum lined plastic tubes in the bile duct of a dog. The development of today's vascular stents began in 1912 when French Nobel Prize winner Alexis Carrel (1873-1944) implanted glass tubes in the arteries of dogs. The first metal spirals were implanted in the arteries of dogs by Charles T. Dotter (1920-1985), while the first stents in human arteries were implanted by French doctors Ulrich Sigwart and Jacques Puel in Toulouse in 1986. Some authors claim that the origin of the word stent is associated with the Scotish word stynt or stent, meaning stretched out river fishing nets. PMID:19348354

  18. Particle Imaging Velocimetry Evaluation of Intracranial Stents in Sidewall Aneurysm: Hemodynamic Transition Related to the Stent Design

    PubMed Central

    Bouillot, Pierre; Brina, Olivier; Ouared, Rafik; Lovblad, Karl-Olof; Farhat, Mohamed; Pereira, Vitor Mendes

    2014-01-01

    We investigated the flow modifications induced by a large panel of commercial-off-the-shelf (COTS) intracranial stents in an idealized sidewall intracranial aneurysm (IA). Flow velocities in IA silicone model were assessed with and without stent implantation using particle imaging velocimetry (PIV). The use of the recently developed multi-time-lag method has allowed for uniform and precise measurements of both high and low velocities at IA neck and dome, respectively. Flow modification analysis of both regular (RSs) and flow diverter stents (FDSs) was subsequently correlated with relevant geometrical stent parameters. Flow reduction was found to be highly sensitive to stent porosity variations for regular stents RSs and moderately sensitive for FDSs. Consequently, two distinct IA flow change trends, with velocity reductions up to 50% and 90%, were identified for high-porosity RS and low-porosity FDS, respectively. The intermediate porosity (88%) regular braided stent provided the limit at which the transition in flow change trend occurred with a flow reduction of 84%. This transition occurred with decreasing stent porosity, as the driving force in IA neck changed from shear stress to differential pressure. Therefore, these results suggest that stents with intermediate porosities could possibly provide similar flow change patterns to FDS, favourable to curative thrombogenesis in IAs. PMID:25470724

  19. Particle imaging velocimetry evaluation of intracranial stents in sidewall aneurysm: hemodynamic transition related to the stent design.

    PubMed

    Bouillot, Pierre; Brina, Olivier; Ouared, Rafik; Lovblad, Karl-Olof; Farhat, Mohamed; Pereira, Vitor Mendes

    2014-01-01

    We investigated the flow modifications induced by a large panel of commercial-off-the-shelf (COTS) intracranial stents in an idealized sidewall intracranial aneurysm (IA). Flow velocities in IA silicone model were assessed with and without stent implantation using particle imaging velocimetry (PIV). The use of the recently developed multi-time-lag method has allowed for uniform and precise measurements of both high and low velocities at IA neck and dome, respectively. Flow modification analysis of both regular (RSs) and flow diverter stents (FDSs) was subsequently correlated with relevant geometrical stent parameters. Flow reduction was found to be highly sensitive to stent porosity variations for regular stents RSs and moderately sensitive for FDSs. Consequently, two distinct IA flow change trends, with velocity reductions up to 50% and 90%, were identified for high-porosity RS and low-porosity FDS, respectively. The intermediate porosity (88%) regular braided stent provided the limit at which the transition in flow change trend occurred with a flow reduction of 84%. This transition occurred with decreasing stent porosity, as the driving force in IA neck changed from shear stress to differential pressure. Therefore, these results suggest that stents with intermediate porosities could possibly provide similar flow change patterns to FDS, favourable to curative thrombogenesis in IAs. PMID:25470724

  20. Drug-Eluting Nitinol Stent Treatment of the Superficial Femoral Artery and Above-the-Knee Popliteal Artery (The Zilver PTX Single-Arm Clinical Study): A Comparison Between Diabetic and Nondiabetic Patients

    SciTech Connect

    Fanelli, Fabrizio; Primo, Massimiliano Di; Boatta, Emanuele; Johnston, Krystal; Sapoval, Marc

    2013-10-15

    Purpose: To describe the 1-year results of drug-eluting nitinol stent placement in the femoropopliteal artery of diabetic and nondiabetic patients. Materials and Methods: All patients enrolled in this prospective, multicenter study underwent paclitaxel-eluting stent placement for de novo or restenotic lesions of the superficial femoral and/or popliteal artery. Baseline and follow-up walking impairment questionnaire (WIQ) scores, Rutherford classifications, and ankle-brachial index (ABI) measurements were obtained. Follow-up was completed at 1, 6, and 12 months. Results: There were 285 diabetic patients and 502 nondiabetic patients treated. There were no significant differences in mean lesion length or lesion calcification between patient groups. Procedural success in both treatment groups was >97 %. There were no significant differences between diabetic and nondiabetic groups in Kaplan-Meier estimates of patency, event-free survival (EFS), or freedom from target lesion revascularization (TLR) at 6 and 12 months. Both groups experienced a significant increase in ABI and WIQ values after treatment, and these improvements were sustained to 12-month follow-up; however, nondiabetic patients had significantly greater 6- and 12-month WIQ scores compared with diabetic patients. Based on covariate analysis, the only factors shown to be significant and to negatively influence patency were longer lesion length (p = 0.009), higher Rutherford classification (p = 0.02), and lack of hypertension (p = 0.02); diabetic status was not found to be a significant factor. Conclusion: Diabetic and nondiabetic patients had similar estimates of primary patency, EFS, and freedom from TLR; however, diabetic patients showed less improvement in WIQ scores compared with nondiabetic patients.

  1. Thermal processing and characterization of 316LVM cardiovascular stent.

    PubMed

    Verma, Arpana; Choubey, Animesh; Raval, Ankur; Kothwala, Devesh

    2006-01-01

    In the current investigation, annealing was employed as a means to improve the mechanical performance of 316LVM coronary stents. Two different temperatures (1000 degrees C and 1150 degrees C) were explored for the thermal processing of the device. Acid pickling was done as a pre-annealing step to remove the debris and slag material attached to the stent after laser cutting. Post annealing operation involved the electrochemical polishing of the device which was also a parameter for assessment of the feasibility of the annealing process. Microstructural characterization, balloon expandability and tensile testing of the stents were performed to characterize the properties after thermal treatment. A fine grained austenitic structure with marked improvement in the % elongation (>40%) could be achieved after annealing the stents at 1000 degrees C. Balloon expandability tests of the stents annealed at 1000 degrees C indicated that the device was implantable. PMID:17119277

  2. Bioresorbable Stents in PCI.

    PubMed

    Lindholm, Daniel; James, Stefan

    2016-08-01

    The evolution of percutaneous coronary intervention has been considerable. Coronary stents were introduced to avoid vessel recoil and reduce acute and late vessel complications. Later, drug-eluting stents were developed to decrease the neointimal hyperplasia associated with bare metal stents in order to reduce restenosis. However, very late stent thrombosis remains problematic, and the permanent presence of a metal stent could be associated with local inflammation and impaired vascular physiology. Thus, bioresorbable stents have been developed, to prevent recoil initially when this risk is the highest, with subsequent degradation over time, to avoid long-term complications of the presence of stents in the coronary vasculature. Here, we review the current status of bioresorbable stents in percutaneous coronary intervention (PCI), with focus on the platforms that have been studied the most: ABSORB, DESolve, and DREAMS. In terms of clinical outcomes, bioresorbable stents have not yet shown superiority compared with current generation drug-eluting stents, but rather a signal of increased stent thrombosis. Further development and longer-term studies are needed before the routine implementation of bioresorbable stents in clinical practice. PMID:27312934

  3. Carbon coating of stents has no effect on inflammatory response to primary stent deployment.

    PubMed

    Korkmaz, Mehmet Emin; Tayfun, Egemen; Müderrisoglu, Haldun; Yildirir, Aylin; Ozin, Bülent; Uluçam, Melek; Turan, Münire

    2002-01-01

    The aim of this study was to investigate the effects of stent carbon coating on inflammatory response. The authors serially measured plasma concentrations of C-reactive protein (CRP), fibrinogen, and several cytokines (tumor necrosis factor, interleukin [IL]-1-beta, IL-6, and IL-8) in patients with single-vessel coronary stenosis who underwent primary stent implantation. None of the subjects had inflammatory or infectious disease at the time of the procedure. Forty-six patients (38 males; mean age 55 +/-9 years) were studied. Blood samples were collected before and at 2, 4, 6, 24, and 48 hours after stent implantation. Patients were randomly assigned 1 of 2 different stent types, an uncoated MAC (AMG Raesfeld-Erle, Germany) (UC-MAC) or a carbon-coated MAC (CC-MAC) stent. Implantations were performed without predilatation, and stents were deployed at a maximum pressure of 6 atmospheres for 90 seconds. Of the 46 patients, 14 had stable, 27 had unstable, and 5 had atypical angina. According to ACC/AHA classification, 35 lesions (76.1%) were type A, 10 (21.7%) were type B, and 1 (2.2%) was type C. Single stenosis of 28 left anterior descending, 12 circumflex, and 6 right coronary arteries were treated. Serum IL-6 increased in both the UC-MAC and CC-MAC groups, with concentrations significantly elevated above baseline at 6 hours, and then decreasing after 24 hours (baseline, 6-hour, and 24-hour values = 3.1 +/-2.3, 5.7 +/-3.8, and 6.3 +/-4.6 pg/mL, respectively, in UC-MAC; 3.7 +/-2.6, 6.2 +/-6.0, and 4.6 +/-3.7 pg/mL, respectively, in CC-MAC [p=0.002]). Plasma fibrinogen, CRP, and leukocyte concentrations also increased in both groups over the 24 hours (p < 0.05). The elevations of IL-6, CRP, and fibrinogen were similar in the 2 groups. The percent increases in IL-6, fibrinogen, and CRP were not associated with stent length, size, or clinical presentation (all p > 0.05). The results showed that stent implantation increases plasma IL-6, fibrinogen, and CRP concentrations

  4. Thoracic Endovascular Stent Graft Repair of Middle Aortic Syndrome.

    PubMed

    Kim, Joung Taek; Lee, Mina; Kim, Young Sam; Yoon, Yong Han; Baek, Wan Ki

    2016-09-01

    Middle aortic syndrome is a rare disease defined as a segmental narrowing of the distal descending thoracic or abdominal aorta. A thoracoabdominal bypass or endovascular treatment is the choice of treatment. Endovascular therapy consists of a balloon dilatation and stent implantation. Recently, thoracic endovascular aortic repair has been widely used in a variety of aortic diseases. We report a case of middle aortic syndrome treated with a thoracic endovascular stent graft. PMID:27549552

  5. Bioabsorbable Stent Quo Vadis: A Case for Nano-Theranostics

    PubMed Central

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

    2014-01-01

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

  6. In vivo Evaluation of Cenderitide-Eluting Stent (CES) II.

    PubMed

    Huang, Yingying; Ng, Xu Wen; Lim, Soon Ghim; Chen, Horng Haur; Burnett, John C; Boey, Yin Chiang Freddy; Venkatraman, Subbu S

    2016-02-01

    The use of drug-eluting coronary stents has led to significant reduction in in-stent restenosis (ISR), but led to delayed endothelialization, necessitating the prolonged use of expensive anti-thrombotic drugs with their side-effects. Cenderitide (CD-NP) is a novel anti-proliferative chimeric peptide of semi-endothelial origin. Our previous work in vitro has demonstrated; that the smooth muscle cells were inhibited significantly more than endothelial cells which is the desirable feature of an anti-restenosis drug. This work reports the effects of implantation of a centeritide-eluting stent (CES) on ISR and endothelialization in an in vivo model. CESs were produced by coating bare metallic stents with CD-NP entrapped in biodegradable poly(ε-caprolactone) using an ultrasonic spray coater. A total of 32 stents were successfully implanted into 16 pigs, and all animal survived for 28 days. The plasma levels of CD-NP were significantly higher in the CES group than in the control group (bare metal stents and polymer-coated stent) at post-stenting, indicating the successful release of CD-NP from the stent in vivo. Furthermore, SEM analysis results showed the greater endothelial coverage of the stent struts, as well as between the struts in CES group. Moreover, histological results showed mild inflammation, and low fibrin score at 28 days. However, plasma cGMP (second messenger, cyclic 3',5' guanosine monophosphate) does not show a significant difference, and the CES is also unable to show significant difference in terms on neointimal area and stenosis, in comparison to BMS at 28 days.

  7. [Recent developments of drug eluting stent coatings].

    PubMed

    Chen, Wen-ping; Zhan, Hong-bing

    2011-11-01

    Drug eluting stents (DESs) have revolutionized the interventional cardiology over the past decade since the first DES became commercially available in Europe in 2002. Compared to bare metal stents that are deployed to keep the vessel open by mechanical force, DESs have an additional function of reducing restenosis by the action of the drug on the target site. Coatings on the stent surface which ensure the maximum delivery of therapeutic agents to the target site with minimal systematic toxicity, also play an important role in adjusting the drug release profile. Coating material and technology not only affect the surface biocompatibility and the integrity maintenance during the implanting process, but also decide the way of drug delivering and transmitting from the coating. This paper reviews the basic principles of DES coating design, the categories of DES coatings, the commonly used clinical DES coatings and their efficiency in reducing restenosis, and finally provides the future perspectives for DES coatings. PMID:22260019

  8. Aortic rupture due to pneumococcal infection in aortoiliac stents.

    PubMed

    Mlynski, Amélie; Mordant, Pierre; Dufour, Guillaume; Augustin, Pascal; Lesèche, Guy; Castier, Yves

    2011-06-01

    We report a rare case of pneumococcal aortitis secondary to endovascular bare-metal stent infection. The patient was a 70-year-old man presenting with back pain 1 year after aortoiliac implantation of bare-metal kissing stents. Final diagnosis was microbial aortitis due to Streptococcus pneumoniae involving the stents that resulted in a contained aortic rupture requiring urgent surgical treatment. Emergency extra-anatomic revascularization, excision of the infected tissues, and appropriate antibiotic therapy led to a favorable outcome. A high index of suspicion is required in such a situation because the mortality rate is very high in the absence of appropriate treatment. PMID:21498029

  9. Aortic stenting.

    PubMed

    Droc, Ionel; Calinescu, Francisca Blanca; Droc, Gabriela; Blaj, Catalin; Dammrau, Rolf

    2015-01-01

    The approach to aortic pathology is nowadays more and more endovascular at both thoracic and abdominal levels. Thoracic stenting has gained worldwide acceptance as first intention to treat pathologies of the descending thoracic aorta. Indications have been extended to aortic arch aneurysms and also to diseases of the ascending aorta. The current devices in use for thoracic endovascular repair (TEVAR) are Medtronic Valiant, Gore TAG, Cook Tx2 and Jotec. The choice of the endograft depends on the thoracic aortic pathology and the anatomical suitability. The technological evolution of the abdominal aortic endografts was very rapid, arriving now at the fourth generation. We report the results of 55 elective cases of endovascular abdominal aortic repair (EVAR) performed in two vascular surgical centers in Romania and Germany. The prostheses used were 16 E-vita Abdominal XT, 12 Excluder, eight Talent, seven PowerLink, three Endurant and nine custom-made, fenestrated or branched from Jotec. The mean follow-up was 18 months with CT-scan, duplex ultrasound and contrast-enhanced ultrasound. The mortality was 2%. EVAR tends to become the gold standard for abdominal aortic aneurysm repair. Technological development of the devices with lowest profile introduction systems will permit to extend the anatomical indications to new frontiers. PMID:26200430

  10. 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.

  11. Study of restenosis in drug eluting stents: new insights from greyscale intravascular ultrasound and virtual histology.

    PubMed

    Garcia-Garcia, Hector M; Shen, Zhujun; Piazza, Nicolo

    2009-05-01

    In current cardiology practice, many patients undergo secondary revascularisation due to reduced long-term vein graft patency or in-stent restenosis. In this report, we describe causes of drug-eluting stent restenosis identifiable by intravascular ultrasound imaging (IVUS) and variables related to restenosis used for reporting greyscale IVUS. In addition, IVUS findings in bypass grafts and the long-term results after stent implantation are provided. Finally, the usefulness of IVUS virtual histology for the study of restenosis is described.

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

    PubMed

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

    2016-01-01

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

  13. Histological analysis of cobalt-chromium stents with and without Camouflage® polymer coating: experimental porcine carotid artery model.

    PubMed

    Grudtner, Marco Aurélio; de Lara Elesbão, Joao Luiz; Gutierrez, Paulo Sérgio; Meyer, Fabíola Schons; Pereira, Adamastor Humberto

    2011-04-01

    This study evaluated the arterial response to cobalt-chromium stents with and without polymer coating (Camouflage®, Hemoteq AG, Wuerselen, Germany) implanted in pigs. Cobalt-chromium balloon-expandable stents (4 × 16 mm) were implanted in the common carotid arteries of nine pigs. Histological analysis of endothelialization, inflammation and injury was performed one month later. All stents were successfully deployed, and all but one animal survived the 30 study days. All arteries were patent. Endothelialization was nearly complete in most sections of all carotid stents in both groups. There were mild inflammatory infiltrate and mild-to-moderate injury, which were associated with the stent shafts and not significantly different between groups. Our findings suggest that, in porcine carotid arteries, the histological response to balloon-expandable cobalt-chromium stents coated with polymer (Camouflage®, Hemoteq AG) is similar to the response to non-coated cobalt-chromium stents.

  14. Oversizing and Restenosis with Self-Expanding Stents in Iliofemoral Arteries

    SciTech Connect

    Saguner, Ardan M. Traupe, Tobias; Raeber, Lorenz; Hess, Nina; Banz, Yara; Saguner, Arhan R.; Diehm, Nicolas; Hess, Otto M.

    2012-08-15

    Purpose: Uncoated self-expanding nitinol stents (NS) are commonly oversized in peripheral arteries. In current practice, 1-mm oversizing is recommended. Yet, oversizing of NS may be associated with increased restenosis. To provide further evidence, NS were implanted in porcine iliofemoral arteries with a stent-to-artery-ratio between 1.0 and 2.3. Besides conventional uncoated NS, a novel self-expanding NS with an antiproliferative titanium-nitride-oxide (TiNOX) coating was tested for safety and efficacy. Methods: Ten uncoated NS and six TiNOX-coated NS (5-6 mm) were implanted randomly in the iliofemoral artery of six mini-pigs. After implantation, quantitative angiography (QA) was performed for calculation of artery and minimal luminal diameter. Follow-up was performed by QA and histomorphometry after 5 months. Results: Stent migration, stent fracture, or thrombus formation were not observed. All stents were patent at follow-up. Based on the location of the stent (iliac/femoral) and the stent-to-artery-ratio, stent segments were divided into 'normal-sized' (stent-to-artery-ratio < 1.4, n = 12) and 'oversized' (stent-to-artery-ratio {>=} 1.4, n = 9). All stent segments expanded to their near nominal diameter during follow-up. Normal-sized stent segments increased their diameter by 6% and oversized segments by 29%. A significant correlation between oversizing and restenosis by both angiography and histomorphometry was observed. Restenosis rates were similar for uncoated NS and TiNOX-coated NS. Conclusions: TiNOX-coated NS are as safe and effective as uncoated NS in the porcine iliofemoral artery. All stents further expand to near their nominal diameter during follow-up. Oversizing is linearly and positively correlated with neointimal proliferation and restenosis, which may not be reduced by TiNOX-coating.

  15. Microwave Spectrometry for the Assessment of the Structural Integrity and Restenosis Degree of Coronary Stents

    NASA Astrophysics Data System (ADS)

    Arauz-Garofalo, Gianluca; Lopez-Dominguez, Victor; Garcia-Santiago, Antoni; Tejada, Javier; O'Callaghan, Joan; Rodriguez-Leor, Oriol; Bayes-Genis, Antoni; Gmag Team; Hugtp Team; Upc Team

    2013-03-01

    Cardiovascular disease is the main cause of death worldwide. Coronary stents are one of the most important improvements to reduce deaths from cardiovascular disorders. Stents are prosthetic tube-shaped devices which are used to rehabilitate obstructed arteries. Despite their obvious advantages, reocclusion occurs in some cases arising from restenosis or structural distortions, so stented patients require chronic monitoring (involving invasive or ionizing procedures). We study microwave scattering spectra (between 2.0 - 18.0 GHz) of metallic stents in open air, showing that they behave like dipole antennas in terms of microwave scattering. They exhibit characteristic resonant frequencies in their microwave absorbance spectra that are univocally related to their length and diameter. This fact allows one to detect stent fractures or collapses. We also investigate the ``dielectric shift'' in the frequency of the resonances mentioned above due to the presence of different fluids along the stent lumen. This shift could give us information about the restenosis degree of implanted stents.

  16. Stent fracture and longitudinal compression detected on coronary CT angiography in the first- and new-generation drug-eluting stents.

    PubMed

    Chung, Mi Sun; Yang, Dong Hyun; Kim, Young-Hak; Roh, Jae-Hyung; Song, Jihyun; Kang, Joon-Won; Ahn, Jung-Min; Park, Duk-Woo; Kang, Soo-Jin; Lee, Seung-Whan; Lee, Cheol Whan; Park, Seong-Wook; Park, Seung-Jung; Lim, Tae-Hwan

    2016-04-01

    To evaluated prevalence and clinical implication of stent fracture and longitudinal compression in first- and new-generation drug-eluting stents (DES) using coronary computed tomography angiography (CCTA). The incidence of stent fracture and longitudinal compression were compared between first- and new-generation DES in 374 patients who underwent coronary stenting using DES and follow-up CCTA due to recurrent angina. 235 and 139 patients received 322 first- and 213 new-generation DES, respectively. The crude per-stent incidence of longitudinal compression (6.1 vs. 0.3 %, p < 0.001) was higher after new- than first-generation DES implantation using CCTA and the incidence of stent fracture (11.3 vs. 8.1 %, p = 0.23) was comparable. On follow-up coronary angiography for 347 stents, stent fracture (3.2 %) and longitudinal compression (0.9 %) were less detected than those on CCTA. Ostial stenting was a risk factor of longitudinal compression (p < 0.001). Stent fracture was associated with younger patients (p = 0.03), longer stent (p = 0.010), and excessively tortuous lesions (p = 0.001). The presence of stent fracture or longitudinal compression was not associated with poor clinical outcomes. The longitudinal compression more frequently occurred after new-generation DES implantation. The stent fracture was comparable between two DES. However, the occurrence of such mechanical deformities did not translate into a poor clinical outcome.

  17. Oxygen Mass Transport in Stented Coronary Arteries.

    PubMed

    Murphy, Eoin A; Dunne, Adrian S; Martin, David M; Boyle, Fergal J

    2016-02-01

    Oxygen deficiency, known as hypoxia, in arterial walls has been linked to increased intimal hyperplasia, which is the main adverse biological process causing in-stent restenosis. Stent implantation has significant effects on the oxygen transport into the arterial wall. Elucidating these effects is critical to optimizing future stent designs. In this study the most advanced oxygen transport model developed to date was assessed in two test cases and used to compare three coronary stent designs. Additionally, the predicted results from four simplified blood oxygen transport models are compared in the two test cases. The advanced model showed good agreement with experimental measurements within the mass-transfer boundary layer and at the luminal surface; however, more work is needed in predicting the oxygen transport within the arterial wall. Simplifying the oxygen transport model within the blood flow produces significant errors in predicting the oxygen transport in arteries. This study can be used as a guide for all future numerical studies in this area and the advanced model could provide a powerful tool in aiding design of stents and other cardiovascular devices.

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

    SciTech Connect

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

    2000-09-15

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

  19. Stent thrombosis in real-world patients: a comparison of drug-eluting with bare metal stents

    PubMed Central

    de Man, F.H.; Stella, P.R.; Nathoe, H.; Kirkels, H.; Hamer, B.; Meijburg, H.W.; Doevendans, P.A.

    2007-01-01

    Background Although the introduction of drugeluting stents (DES) has been associated with an impressive reduction in target vessel revascularisation, there has been concern about the safety profile. The aim of this study was to determine the incidence of stent thrombosis in real-world patients and evaluate the contribution of drug-eluting stents. Methods A prospective observational cohort study was conducted at a high-volume centre in Utrecht, the Netherlands. All patients who underwent a percutaneous coronary intervention (PCI) between 1 January and 31 December 2005 were evaluated. The patients were pretreated with aspirin and clopidogrel, which was continued for six months in bare metal stents (BMS) and 12 months in DES. Results In 2005, 1309 patients underwent a percutaneous coronary intervention procedure with stent implantation. After a median follow-up of nine months, 1.8% (n=23) of the patients had suffered from stent thrombosis. Two cases could be attributed to incorrect use of antiplatelet agents. In 8/23 cases, a technical reason was found such as an unrecognised dissection or stent underexpansion. The timing of stent thrombosis was acute in 1/23 patients, subacute in 20/23 patients and late in 2/23 patients. In both cases of late stent thrombosis, a BMS had been used. There were no differences in stent thrombosis rates between DES and BMS (1.4 vs. 1.9%, ns.). This is remarkable since DES were used in more complex and longer lesions. Conclusion The use of DES in routine daily practice does not appear to be associated with a higher rate of stent thrombosis than BMS. (Neth Heart J 2007;15:382-6.18176640Neth Heart J 2007;15:382-6). PMID:18176640

  20. Percutaneous stent placement in children weighing less than 10 kilograms.

    PubMed

    Ashwath, Ravi; Gruenstein, Daniel; Siwik, Ernest

    2008-05-01

    The objectives of this study were to evaluate the safety, efficacy, and outcomes of palliative percutaneous stent placement in infants with congenital heart disease (CHD). There is interest in improving outcomes of infants with CHD through interventional/surgical collaboration. Small, high-risk patients may benefit from delayed open operations, and endovascular stents may provide a means to defer surgery to more advantageous times in select infants. Patients weighing < or =10 kg in whom stent placement was attempted during 2003-2006 were identified. Diagnoses, indications, angiographic and hemodynamic data, complications, and outcomes were reviewed. Seventeen stents were successfully placed in 15 patients. The mean age was 10.21 months; the mean weight was 6.08 kg. Indications were branch pulmonary artery stenosis, coarctation, total anomalous pulmonary venous return with obstructed venous egress, right ventricle-pulmonary artery conduit, and shunt stenosis. Premounted Palmaz Genesis and Driver Mx stents were used. Average vessel diameter increased from 3.65 to 6.72 mm (p < 0.001). The pressure gradient fell from 24 to 15 mm Hg (p < 0.01). Two stents migrated. One was recaptured and implanted at the target site and one implanted away from the target site. None needed surgical intervention. Mean follow-up was 270 days. Five patients have had additional surgery; seven patients underwent 10 additional stent dilations. There was no procedural-related mortality. Five patients (33%) died during the follow-up period, none attributable to the stent placement. We conclude that stent placement can be successfully accomplished in select, small, high-risk patients. A collaborative interventional/surgical paradigm is important to ensure that the risk-benefit ratio is properly evaluated during the patient selection. PMID:18046599

  1. High-resolution CT and angiographic evaluation of NexStent wall adaptation.

    PubMed

    Nemes, Balázs; Lukács, Levente; Balázs, György; Dósa, Edit; Bérczi, Viktor; Hüttl, Kálmán

    2009-05-01

    Carotid stenting is a minimally invasive treatment for extracranial carotid artery stenosis. Stent design may affect technical success and complications in a certain subgroup of patients. We examined the wall adaptability of a new closed-cell carotid stent (NexStent), which has a unique rolled sheet design. Forty-one patients had 42 carotid arteries treated with angioplasty and stenting for internal carotid artery stenosis. The mean patient age was 65 +/- 10 years. All patients underwent high-resolution computed tomographic angiography after the stent implantation. Data analysis included pre- and postprocedural stenosis, procedure complications, plaque calcification, and stent apposition. We reviewed the angiographic and computed tomographic images for plaque coverage and stent expansion. All procedures were technically successful. Mean stenosis was reduced from 84 +/- 8% before the procedure to 15.7 +/- 7% after stenting. Two patients experienced transient ischemic attack; one patient had bradycardia and hypotension. Stent induced kinking was observed in one case. Good plaque coverage and proper overlapping of the rolled sheet was achieved in all cases. There was weak correlation between the residual stenosis and the amount of calcification. The stent provides adequate expansion and adaptation to the tapering anatomy of the bifurcation. PMID:19159971

  2. Determination of Stent Stenosis: An In Vivo Experimental Comparison of Intravascular Ultrasound and Angiography with Histology

    SciTech Connect

    Schuermann, Karl; Vorwerk, Dierk; Uppenkamp, Robert; Klosterhalfen, Bernd; Buecker, Arno; Guenther, Rolf W.

    1998-05-15

    Purpose: To compare intravascular ultrasound (IVUS) and angiography with histology in determining the degree of stent stenosis in an in vivo experiment. Methods: In 16 sheep, a total of 64 stents were implanted into the external iliac arteries. Two stents were inserted on either side. Patency was followed by angiography and IVUS. Four types of stent were used: two Dacron-covered (Cragg Endopro and heparinized Cragg Endopro) and two non-covered (Cragg and Memotherm stents). Eight animals were killed after 1 month, eight others after 6 months. Histological sections were prepared from the stented vessels. Measurements of the patent and total stent diameters determined by IVUS, angiography, and histology were compared. Results: Correlation between IVUS and angiography was 0.75, between IVUS and histology 0.77, and between angiography and histology 0.85. A mean stent stenosis of 17 {+-} 11% (range 0-51%) was found on angiography, of 10 {+-} 11% (0-46%) on IVUS, and of 20 {+-} 11% (4%-49%) on histology. In comparison with histology, IVUS underestimated the degree of stenosis by 10 {+-} 8%, and angiography underestimated it by 3 {+-} 6%. Resolution of IVUS was calculated to be about 0.35 mm and that of angiography to be about 0.15 mm. Conclusion: Under experimental conditions, IVUS was not superior to angiography in determining the degree of stent stenosis in long-segment stenoses of iliac artery stents, when measurements were correlated with histology. Angiography is sufficient for following the patency of iliac artery stents.

  3. High-Resolution CT and Angiographic Evaluation of NexStent Wall Adaptation

    SciTech Connect

    Nemes, Balazs Lukacs, Levente; Balazs, Gyoergy; Dosa, Edit; Berczi, Viktor; Huettl, Kalman

    2009-05-15

    Carotid stenting is a minimally invasive treatment for extracranial carotid artery stenosis. Stent design may affect technical success and complications in a certain subgroup of patients. We examined the wall adaptability of a new closed-cell carotid stent (NexStent), which has a unique rolled sheet design. Forty-one patients had 42 carotid arteries treated with angioplasty and stenting for internal carotid artery stenosis. The mean patient age was 65 {+-} 10 years. All patients underwent high-resolution computed tomographic angiography after the stent implantation. Data analysis included pre- and postprocedural stenosis, procedure complications, plaque calcification, and stent apposition. We reviewed the angiographic and computed tomographic images for plaque coverage and stent expansion. All procedures were technically successful. Mean stenosis was reduced from 84 {+-} 8% before the procedure to 15.7 {+-} 7% after stenting. Two patients experienced transient ischemic attack; one patient had bradycardia and hypotension. Stent induced kinking was observed in one case. Good plaque coverage and proper overlapping of the rolled sheet was achieved in all cases. There was weak correlation between the residual stenosis and the amount of calcification. The stent provides adequate expansion and adaptation to the tapering anatomy of the bifurcation.

  4. Multi-scale mechanical investigation of stainless steel and cobalt-chromium stents.

    PubMed

    Kapnisis, Konstantinos; Constantinides, Georgios; Georgiou, Harry; Cristea, Daniel; Gabor, Camelia; Munteanu, Daniel; Brott, Brigitta; Anderson, Peter; Lemons, Jack; Anayiotos, Andreas

    2014-12-01

    In-stent restenosis (ISR) remains a significant limitation despite the considerable previous clinical and investigative emphasis on the problem. Complications arising from the interaction of stent materials with the surrounding vessel wall as well as from the mechanical forces developing after implantation, play an important role in the development of ISR. To investigate the relation between mechanical factors and stent structural integrity, and to identify any structural weakness points on the geometry of commercially available Stainless Steel and Cobalt-Chromium stents, accelerated pulsatile durability tests were carried out in a simulated physiological environment. Potential spatial variations in the mechanical properties on stent struts and their role in the observed premature failures of the stent devices during operation were also examined. Fretting wear and fatigue-induced fractures were found on stent surfaces after exposure to cyclic loading similar to that arising in vivo. Nanoindentation studies performed on various locations along the stent struts have shown that the hardness of specific stent locations significantly increases after mechanical expansion. The increase in hardness was associated with a reduction of the material's ability to dissipate energy in plastic deformations, therefore an increased vulnerability to fracture and fatigue. We conclude that the locations of fatigue fractures in stent struts are controlled not only by the geometrically-driven stress concentrations developing during cyclic loading but also by the local material mechanical changes that are imparted on various parts of the stent during the deployment process.

  5. Long-Term Histopathologic and IVUS Evaluations of a Novel Coiled Sheet Stent in Porcine Carotid Arteries

    SciTech Connect

    Kaneda, Hideaki; Ikeno, Fumiaki Lyons, Jennifer; Rezaee, Mehrdad; Yeung, Alan C.; Fitzgerald, Peter J.

    2006-06-15

    Carotid angioplasty with stent placement has been proposed as an alternative method for revascularization of carotid artery stenosis. A novel stent with a laser-cut, rolled sheet of Nitinol (EndoTex Interventional Systems, Inc., Cupertino, CA) has been developed to customize treatment of stenotic lesions in carotid arteries utilizing a single stent, designed to adapt to multiple diameters and to tapered or nontapered configurations. The purpose of this study is to evaluate the conformability and vascular response to a novel stent in a chronic porcine carotid model using serial three-dimensional intravascular ultrasound (IVUS) analysis as well as histological examination. Ten Yucatan pigs underwent stent implantation in both normal carotid arteries with adjunctive balloon angioplasty. Three-dimensional IVUS analysis was performed before stent implantation, after adjunctive balloon angioplasty, and at follow-up [1 month (n = 6), 3 months (n = 6), or 6 months (n = 8)]. Histological examination (injury score, percent plaque obstruction, and qualitative analysis) was also performed. All stents were successfully deployed and well apposed in different sized vessels (lumen area range: 19-30 mm{sup 2}). Volumetric IVUS analysis showed no significant difference between the lumen areas before stent implantation and after adjunctive balloon angioplasty and no stent area change at each follow-up point compared to immediately postprocedure. Histological examination revealed minimal injury and neointimal hyperplasia at each follow-up point. In the chronic porcine carotid model, the novel stent system demonstrated good conformability, resulting in minimal vessel injury and neointimal formation.

  6. Stent selection in patients with myocardial infarction: drug eluting, biodegradable polymers or bare metal stents?

    PubMed

    Mieres, Juan; Rodríguez, Alfredo E

    2012-08-01

    Percutaneous coronary intervention (PCI) has been increasingly used in the last years during interventional procedures in patients with acute coronary syndromes (ACS) including ST elevation myocardial infarction (STEMI) and non-ST elevation myocardial infarction (NSTEMI). In patients with either STEMI, NSTEMI, high risk ACS with EKG changes or cardiac enzymes rises; PCI with bare metal stent (BMS) implantation has been associated with a significant improvement in clinical outcome. Therefore, BMS implantation during primary PCI in STEMI has become a standard of practice. With the introduction of drug eluting stents (DESs) in this decade, the use of these new devices instead of BMSs in patients with STEMI has emerged as a rational PCI alternative in this particular subgroup of patients. In spite of the unquestionable benefits of DESs in terms of reduction of restenosis and TVR, specific concerns have arisen with regard to their long-term safety. High incidence of very late stent thrombosis has been described with these devices, and special attention should be paid in patients with unstable coronary lesions, in which plaque composition and remodeling may play a main role in their safety and long-term outcome. Intraluminal thrombus caused by plaque rupture is the most frequent mechanism of STEMI, in which the necrotic core and thin fibrous cap play a major role. In this context, the use of first DESs designs may be futile or even unsafe because delayed healing may further contribute to plaque instability. Adjunctive invasive imaging tools can improve stent deployment and safety outcome in these lesions with intravascular findings of plaque instability. Recently, other players such as new dedicated antithrombotic BMS designs, including selfexpanding stents or drug-eluting coated balloons, are exploring their potential indications in patients with ACS and myocardial infarction. This paper reports and discusses new stent devices and adjunctive pharmacologic agents. It

  7. Stent Thrombosis Patients with Hyporesponsiveness to Clopidogrel, Prasugrel, and Ticagrelor: A Case Series Using Short Thromboelastography

    PubMed Central

    Sambu, Nalyaka; Mahmoudi, Michael; Curzen, Nick

    2016-01-01

    Patients after percutaneous coronary intervention (PCI) with stent implantation and functional hyporesponsiveness to P2Y12 inhibitors are at higher risk of ischaemic events, particularly stent thrombosis (ST). It is currently not routine practice to assess the functional response to these agents. However, concern over functional hyporesponsiveness to clopidogrel has led to widespread uptake of prasugrel and ticagrelor as the default P2Y12 inhibitor after stent implantation in patients with acute coronary syndrome. Here we report, for the first time, 3 cases in which patients who have had ST exhibit hyporesponsiveness to clopidogrel, prasugrel, and ticagrelor. PMID:27799942

  8. Application of chemokine receptor antagonist with stents reduces local inflammation and suppresses cancer growth.

    PubMed

    Mao, Ai-Wu; Jiang, Ting-Hui; Sun, Xian-Jun; Peng, Jian

    2015-11-01

    Severe pain and obstructive jaundice resulting from invasive cholangiocarcinoma or pancreatic carcinoma can be alleviated by implantation of biliary and duodenal stents. However, stents may cause local inflammation to have an adverse effect on the patients' condition and survival. So far, no efficient approaches have been applied to prevent the occurrence of stents-related inflammation. Here, we reported significantly higher levels of serum stromal cell-derived factor 1 (SDF-1) in the patients that developed stents-associated inflammation. A higher number of inflammatory cells have been detected in the cancer close to stent in the patients with high serum SDF-1. Since chemokine plays a pivotal role in the development of inflammation, we implanted an Alzet osmotic pump with the stents to gradually release AMD3100, a specific inhibitor binding of SDF-1 and its receptor C-X-C chemokine receptor 4 (CXCR4), at the site of stents in mice that had developed pancreatic cancer. We found that AMD3100 significantly reduced local inflammation and significantly inhibited cancer cell growth, resulting in improved survival of the mice that bore cancer. Moreover, the suppression of cancer growth may be conducted through modulation of CyclinD1, p21, and p27 in the cancer cells. Together, these data suggest that inhibition of chemokine signaling at the site of stents may substantially improve survival through suppression of stent-related inflammation and tumor growth.

  9. Successful Management of Coronary Artery Rupture with Stent-Graft: A Case Report

    PubMed Central

    Erkan, Aycan Fahri; Kütük, Utku; Töre, Hasan Fehmi

    2014-01-01

    Perforation of coronary arteries is a relatively rare yet life-threatening complication of percutaneus coronary interventions and is encountered in approximately 0.5% of these procedures. According to the type of coronary perforation, various methods of correction are employed, ranging from conservative approach to emergency cardiac surgery. Coronary stent-grafts are composed of two metal stents and a polytetrafluoroethylene layer between them. Advent of such stents enabled efficient endovascular repair of coronary artery perforation. We present a case of coronary artery perforation which had occurred during stent implantation for the treatment of a bridged segment in the distal portion of the left anterior descending artery. This perforation was successfully managed by implanting a stent-graft. PMID:25126095

  10. Improved bioresorbable microporous intravascular stents for gene therapy.

    PubMed

    Ye, Y W; Landau, C; Meidell, R S; Willard, J E; Moskowitz, A; Aziz, S; Carlisle, E; Nelson, K; Eberhart, R C

    1996-01-01

    Drug imbibing microporous stents are under development at a number of centers to enhance healing of the arterial wall after balloon coronary angioplasty procedures. The authors improved the mechanical strength and reservoir properties of a biodegradable microporous stent reported to this Society in 1994. A combined tubular/helical coil stent is readily fabricated by flotation/precipitation and casting/ winding techniques. A two stage solvent swelling technique allows precise adjustment of the surface hydrophilic/hydrophobic balance. These developments permit seven-fold improvement in drug capacity without significantly altering mechanical properties. Stents modified in this manner retain tensile and compressive strength and are suitable for remote deployment. Elution kinetics of these modified stents suggest they are suitable for gene delivery. Successful gene transfer and transmural expression have been demonstrated after implantation of stents impregnated with a recombinant adenovirus carrying a nuclear localizing beta-galactosidase reporter gene into rabbit carotid arteries. These studies suggest that surface modified, bioresorbable polymer stents ultimately may be useful adjunctive devices for gene transfer during percutaneous transluminal revascularization.

  11. Gastric and Duodenal Stents: Follow-Up and Complications

    SciTech Connect

    Pinto Pabon, Isabel Teresa; Paul Diaz, Laura; Ruiz de Adana, Juan Carlos; Lopez Herrero, Julio

    2001-05-15

    Purpose: To assess the efficacy of self-expanding metallic stents in treating inoperable gastric and duodenal stenoses during follow-up and to evaluate the complications encountered.Methods: A total of 31 patients suffering from gastroduodenal obstruction (29 malignant, 2 benign) were treated with a self-expanding metallic stent (Wallstent). In 24 cases insertion was by the peroral route, in seven cases via gastrostomy.Results: All the strictures were successfully negotiated under fluoroscopic guidance without having to resort to endoscopy. A total of 27 patients (87%) were able to resume a regular diet, a soft diet, or a liquid diet orally. Complications included one case of stent malpositioning, one case of leakage of ascitic fluid through the gastrostomy orifice, one case of perforation and fistula to the biliary tree, and two cases of hematemesis. In two patients (6%) additional stents were implanted to improve patency. In all patients follow-up was maintained until death. Recurrence of symptoms immediately before death occurred in seven cases (23%). Mean survival time of patients was 13.3 weeks (SE {+-} 4.6).Conclusions: The deployment of gastroduodenal stents resulted in good palliation of inoperable gastric and duodenal stenoses. Certain technical aspects, e.g., adaptation of stents to bowel morphology, is critical to proper stent function and avoidance of complications.

  12. Corrosion resistance of polyurethane-coated nitinol cardiovascular stents.

    PubMed

    Mazumder, M M; De, S; Trigwell, S; Ali, N; Mazumder, M K; Mehta, J L

    2003-01-01

    Corrosion of metal stents implanted inside an artery can have two adverse effects: (1) tissue reaction and possible toxic effects from the metal ions leaching out of the stent, and (2) loss of mechanical strength of the stent caused by corrosion. The corrosion resistance of Nitinol (Nickel-Titanium) stents and its modulation with different film thickness of polymer coating was studied against an artificial physiological solution using a Potentiostat/Galvanostat and an electrochemical corrosion cell. The corrosion rate decreased rapidly from 275 microm/year for an uncoated surface down to less than 13 microm/year for a 30 microm thick polyurethane coating. Stainless steel (316L) and Nitinol both contain potentially toxic elements, and both are subject to stress corrosion. Minimization of corrosion can significantly reduce both tissue reaction and structural degradation.

  13. Intravascular stenting for the treatment of coarctation of the aorta in adolescent and adult patients.

    PubMed

    Godart, François

    2011-12-01

    In the past 10 years, stent implantation has become a real alternative to surgery in the management of both native and recurrent coarctation of the aorta in adolescents and adults. The purpose of this report is to provide a detailed review of stent implantation techniques, including pre-procedure imaging, technical aspects and results. The success rate is usually high (around 90%), and the procedure results in an increase in the diameter of the coarcted segment, a decrease in the transisthmic systolic gradient and a better control of systemic hypertension. The most serious complication, rupture of the aorta, can be fatal, but is rare (< 2%). Aneurismal dilatation is another potential problem that occurs in around 5-9% of cases, and may be related to overstretching and pre-stent dilatation, so these should be avoided. It is necessary to point out that most of these aneurysms are small and conservatively managed. Restenosis is another complication that may result from neointimal proliferation, stent recoil and stent fracture. Balloon dilatation with a higher inflating pressure or repeat stent implantation is proposed herein. A comparison with surgery is also discussed, and a follow-up protocol is proposed to capture late complications. Owing to good initial and intermediate results, stent implantation is nowadays considered as a first-line therapy in most adolescents and adults with (re)coarctation of the aorta.

  14. 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.

  15. Coronary artery stent (image)

    MedlinePlus

    ... with a balloon catheter and expands when the balloon is inflated. The stent is then left there to help keep the artery open. ... with a balloon catheter and expands when the balloon is inflated. The stent is then left there to help keep the artery open.

  16. Graphene for Biomedical Implants

    NASA Astrophysics Data System (ADS)

    Moore, Thomas; Podila, Ramakrishna; Alexis, Frank; Rao, Apparao; Clemson Bioengineering Team; Clemson Physics Team

    2013-03-01

    In this study, we used graphene, a one-atom thick sheet of carbon atoms, to modify the surfaces of existing implant materials to enhance both bio- and hemo-compatibility. This novel effort meets all functional criteria for a biomedical implant coating as it is chemically inert, atomically smooth and highly durable, with the potential for greatly enhancing the effectiveness of such implants. Specifically, graphene coatings on nitinol, a widely used implant and stent material, showed that graphene coated nitinol (Gr-NiTi) supports excellent smooth muscle and endothelial cell growth leading to better cell proliferation. We further determined that the serum albumin adsorption on Gr-NiTi is greater than that of fibrinogen, an important and well understood criterion for promoting a lower thrombosis rate. These hemo-and biocompatible properties and associated charge transfer mechanisms, along with high strength, chemical inertness and durability give graphene an edge over most antithrombogenic coatings for biomedical implants and devices.

  17. Bioresorbable Electronic Stent Integrated with Therapeutic Nanoparticles for Endovascular Diseases.

    PubMed

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

    2015-06-23

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

  18. Use of an introducer sheath for colonic stent placement.

    PubMed

    De Gregorio, Miguel A; Mainar, Antonio; Tejero, Eloy; Alfonso, Eduardo; Gimeno, María José; Herrera, Marcos

    2002-09-01

    We describe a technical modification of Wallstent implantation for the treatment of malignant rectosigmoid and descending colonic obstructions. The modification is the routine placement of an introducer sheath via the rectum before stent implantation in order to straighten the rectosigmoid region. This device facilitates catheter and guide wire manipulations and obtaining specimen biopsies for histopathological studies. The introducer sheath has been used without complications in 21 consecutive patients.

  19. Biodegradable-Polymer Biolimus-Eluting Stents versus Durable-Polymer Everolimus-Eluting Stents at One-Year Follow-Up: A Registry-Based Cohort Study.

    PubMed

    Parsa, Ehsan; Saroukhani, Sepideh; Majlessi, Fereshteh; Poorhosseini, Hamidreza; Lofti-Tokaldany, Masoumeh; Jalali, Arash; Salarifar, Mojtaba; Nematipour, Ebrahim; Alidoosti, Mohammad; Aghajani, Hassan; Amirzadegan, Alireza; Kassaian, Seyed Ebrahim

    2016-04-01

    We compared outcomes of percutaneous coronary intervention patients who received biodegradable-polymer biolimus-eluting stents with those who received durable-polymer everolimus-eluting stents. At Tehran Heart Center, we performed a retrospective analysis of the data from January 2007 through December 2011 on 3,270 consecutive patients with coronary artery disease who underwent percutaneous coronary intervention with the biodegradable-polymer biolimus-eluting stent or the durable-polymer everolimus-eluting stent. We excluded patients with histories of coronary artery bypass grafting or percutaneous coronary intervention, acute ST-segment-elevation myocardial infarction, or the implantation of 2 different stent types. Patients were monitored for 12 months. The primary endpoint was a major adverse cardiac event, defined as a composite of death, nonfatal myocardial infarction, and target-vessel and target-lesion revascularization. Durable-polymer everolimus-eluting stents were implanted in 2,648 (81%) and biodegradable-polymer biolimus-eluting stents in 622 (19%) of the study population. There was no significant difference between the 2 groups (2.7% vs 2.7%; P=0.984) in the incidence of major adverse cardiac events. The cumulative adjusted probability of major adverse cardiac events in the biodegradable-polymer biolimus-eluting stent group did not differ from that of such events in the durable-polymer everolimus-eluting stent group (hazard ratio=0.768; 95% confidence interval, 0.421-1.44; P=0.388). We conclude that in our patients the biodegradable-polymer biolimus-eluting stent was as effective and safe, during the 12-month follow-up period, as was the durable-polymer everolimus-eluting stent.

  20. The virtual histology intravascular ultrasound appearance of newly placed drug-eluting stents.

    PubMed

    Kim, Sang-Wook; Mintz, Gary S; Hong, Young-Joon; Pakala, Rajbabu; Park, Kyung-Sook; Pichard, Augusto D; Satler, Lowell F; Kent, Kenneth M; Suddath, William O; Waksman, Ron; Weissman, Neil J

    2008-11-01

    Intravascular ultrasound (IVUS) is used before and after intervention and at follow-up to assess the quality of the acute result as well as the long-term effects of stent implantation. Virtual histology (VH) IVUS classifies tissue into fibrous and fibrofatty plaque, dense calcium, and necrotic core. Although most interventional procedures include stent implantation, VH IVUS classification of stent metal has not been validated. In this study, the VH IVUS appearance of acutely implanted stents was assessed in 27 patients (30 lesions). Most stent struts (80%) appeared white (misclassified as "calcium") surrounded by red (misclassified as "necrotic core"); 2% appeared just white, and 17% were not detectable (compared with grayscale IVUS because of the software-imposed gray medial stripe). The rate of "white surrounded by red" was similar over the lengths of the stents; however, undetectable struts were mostly at the distal edges (31%). Quantitatively, including the struts within the regions of interest increased the amount of "calcium" from 0.23 +/- 0.35 to 1.07 +/- 0.66 mm(2) (p <0.0001) and the amount of "necrotic core" from 0.59 +/- 0.65 to 1.31 +/- 0.87 mm(2) (p <0.0001). Most important, because this appearance occurs acutely, it is an artifact, and the red appearance should not be interpreted as peristrut inflammation or necrotic core when it is seen at follow-up. In conclusion, acutely implanted stents have an appearance that can be misclassified by VH IVUS as "calcium with or without necrotic core." It is important not to overinterpret VH IVUS studies of chronically implanted stents when this appearance is observed at follow-up. A separate classification for stent struts is necessary to avoid these misconceptions and misclassifications.

  1. [Stent dilatation of pulmonary artery stenosis in the adult patient with congenital heart disease].

    PubMed

    Benito, F; Oliver, J M

    2000-04-01

    Stents have been previously used to resolve stenoses of branch pulmonary arteries in children. We report 3 patients, with mean age of 22.7 +/- 4.7 years and pulmonary artery stenosis after palliative surgery in whom we implanted seven stents in four procedures. Six P308 Palmaz, overlapped two by two, were implanted by venous femoral approach in two patients, receiving four in the first case and the other two in the third case. In the second case, a NIR type stent was implanted through femoral artery in the right pulmonary artery. Stenosis diameter enlarged from 5.3 +/- 2.3 to 14.4 +/- 4.2 mm and the pressure gradient through stenosis fell from 40.6 +/- 15.3 to 6. 5 +/- 5 mmHg. All stents are well deployed and there are two patients waiting for total correction (previously not feasible) during a follow-up of 30.6 +/- 6.1 months.

  2. Drug diffusion and biological responses of arteries using a drug-eluting stent with nonuniform coating

    PubMed Central

    Saito, Noboru; Mori, Yuhei; Uchiyama, Sayaka

    2016-01-01

    The purpose of this study was to determine the effect of a nonuniform coating, abluminal-gradient coating (AGC), which leaves the abluminal surface of the curves and links parts of the stent free from the drug coating, on the diffusion direction of the drug and the biological responses of the artery to drug-eluting stent (DES) by comparing the AGC-sirolimus stent and the conventional full-surface coating (CFC) sirolimus stent. The study aimed to verify whether the AGC approach was appropriate for the development of a safer DES, minimizing the risks of stent thrombosis due to delayed endothelialization by the drug and distal embolization due to cracking of the coating layer on the hinge parts of the DES on stent expansion. In the in vitro local drug diffusion study, we used rhodamine B as a model drug, and rhodamine B released from the AGC stent diffused predominantly into the abluminal side of the alginate artery model. Conversely, rhodamine B released from the CFC stent quickly spread to the luminal side of the artery model, where endothelial cell regeneration is required. In the biological responses study, the luminal surface of the iliac artery implanted with the AGC-sirolimus stent in a rabbit iliac artery for 2 weeks was completely covered with endothelial-like cells. On the other hand, the luminal surface of the iliac artery implanted with the CFC-sirolimus stent for 2 weeks only showed partial coverage with endothelial-like cells. While thrombosis was observed in two of the three CFC-sirolimus stents, it was observed in only one of the three AGC-sirolimus stents. Taken together, these findings indicate that the designed nonuniform coating (AGC) is an appropriate approach to ensure a safer DES. However, the number of studies is limited and a larger study should be conducted to reach a statistically significant conclusion. PMID:27051322

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

    SciTech Connect

    Yamamoto, Kiyosei Yoshioka, Tetsuya; Furuichi, Kinya; Sakaguchi, Hiroshi; Anai, Hiroshi; Tanaka, Toshihiro; Morimoto, Kengo; Uchida, Hideo; Kichikawa, Kimihiko

    2011-06-15

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

  4. Characterization of nanostructured ureteral stent with gradient degradation in a porcine model

    PubMed Central

    Wang, Xiaoqing; Shan, Hongli; Wang, Jixue; Hou, Yuchuan; Ding, Jianxun; Chen, Qihui; Guan, Jingjing; Wang, Chunxi; Chen, Xuesi

    2015-01-01

    A tubular poly(ε-caprolactone) (PCL)/poly(lactide-co-glycolide) (PLGA) ureteral stent composed of nanofibers with micropores was fabricated by double-needle electrospinning. The stent was ureteroscopically inserted into six Changbai pigs, and the commercial polyurethane Shagong® stent was inserted into four pigs as control. Intravenous pyelography revealed that the PCL/PLGA stent gradually degraded from the distal end to proximal terminal, and all stents were completely degraded at 10 weeks post-insertion. No significant difference was observed in hydronephrosis severity between the two groups. The levels of serum creatinine and urine pH remained similar throughout the study in the two groups, but the number of white blood cells in the urine was significantly higher in the Shagong® stent group. On Day 70, histological evaluation indicated equivalent histological severity scores in the middle and distal ureter sections and bladder in the two groups. However, the PCL/PLGA stent-implanted pigs had significantly lower mean severity scores in the kidney and proximal ureter sites. These data revealed that the PCL/PLGA stent degraded in a controlled manner, did not induce obstruction, and had a lower urothelial impact in comparison to the Shagong® stent, indicating that the stent exhibited great potential for clinical application. PMID:25945051

  5. External heating of stents by radio waves Pilot studies in rabbit aorta

    SciTech Connect

    Levitt, Adam B.; Robinson, Keith; Chronos, Nicolas A.F.; Daum, Wolfgang

    2003-09-01

    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: 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.

  6. Fracture and Collapse of Balloon-Expandable Stents in the Bilateral Common Iliac Arteries Due to Shiatsu Massage

    SciTech Connect

    Ichihashi, Shigeo Higashiura, Wataru; Itoh, Hirofumi; Sakaguchi, Shoji; Kichikawa, Kimihiko

    2012-12-15

    We report a case of stent fracture and collapse of balloon-expandable stents caused by shiatsu massage. A 76-year-old man presented with complaints of intermittent claudication of the right lower extremity. Stenoses of the bilateral common iliac arteries (CIAs) were detected. Balloon-expandable stents were deployed in both CIAs, resulting in resolution of symptoms. Five months later, pelvis x-ray showed collapse of both stents. Despite the stent collapse, the patient was asymptomatic, and his ankle brachial index values were within the normal range. Further history showed that the patient underwent daily shiatsu therapy in the umbilical region, which may have triggered collapse of the stent. Physicians should advise patients to avoid compression of the abdominal wall after implantation of a stent in the iliac artery.

  7. Cutting balloon angioplasty for carotid artery in-stent stenosis supported by three-dimensional rotational angiography with automated vessel analysis software.

    PubMed

    Akiyama, Yasuhiko; Moritake, Kouzo; Miyazaki, Takeshi; Kowari, Kentaro; Sato, Hidetoshi; Shimada, Toshio

    2008-05-01

    In-stent stenosis is a possible long-term complication of carotid artery stenting. A simple and safe technique of cutting balloon angioplasty is described for carotid in-stent stenosis. The stented vessel is imaged by three-dimensional (3D) rotational angiography, the acquired projection images are transferred to a workstation, and the stenotic lesion and implanted stent are reconstructed. The diameter of the implanted stent in the stenotic region is measured by automated analysis software. Cutting balloon angioplasty carries the risk of vessel injury by the cutting balloon microblades, but the implanted stent acts as a barrier to protect the vessel. Therefore, cutting balloon inflation up to the stent diameter is safe and results in maximal vessel dilation. The key to success is precise measurement of the stent diameter and choice of a cutting balloon catheter of the appropriate size. 3D rotational angiography provides high-quality images of the vasculature of a stented vessel and a reference for intervention based on absolute measurements. Cutting balloon angioplasty supported by 3D rotational angiography with automated vessel analysis software should be considered as a treatment strategy for high-grade carotid artery in-stent stenosis. PMID:18497500

  8. Colorectal Stenting: An Effective Therapy for Preoperative and Palliative Treatment

    SciTech Connect

    Jost, Rahel S. Jost, Res; Schoch, Erich; Brunner, Brigit; Decurtins, Marco; Zollikofer, Christoph L.

    2007-06-15

    Purpose. To demonstrate the effectiveness of preoperative and palliative colorectal stent placement in acute colonic obstruction. Methods. Sixty-seven consecutive patients (mean age 67.3 years, range 25-93 years) with clinical and radiological signs of colonic obstruction were treated: 45 (67%) preoperatively and 22 (33%) with a palliative intent. In 59 patients (88%) the obstruction was malignant, while in 8 (12%) it was benign. A total of 73 enteric Wallstents were implanted under combined fluoroscopic/endoscopic guidance. Results. Forty-five patients were treated preoperatively with a technical success rate of 84%, a clinical success rate of 83%, and a complication rate of 16%. Of the 38 patients who were successfully stented preoperatively, 36 (95%) underwent surgery 2-22 days (mean 7.2 days) after stent insertion. The improved general condition and adequate bowel cleansing allowed single-stage tumor resection and primary end-to-end anastomosis without complications in 31 cases (86% of all operations), while only 5 patients had colostomies. Stent placement was used as the final palliative treatment in 22 patients. The technical success rate was 95%, the clinical success rate 72%, and the complication rate relatively high at 67%, caused by reocclusion in most cases. After noninvasive secondary interventions (e.g., tube placement, second stenting, balloon dilatation) the secondary patency of stents was 71% and mean reported survival time after stent insertion was 92 days (range 10-285 days). Conclusion. Preoperative stent placement in acute colonic obstruction is minimally invasive and allows an elective one-stage surgery in most cases. Stent placement also proved a valuable alternative to avoid colostomy in palliation.

  9. Biocompatibility of phosphorylcholine coated stents in normal porcine coronary arteries

    PubMed Central

    Whelan, D; van der Giessen, W J; Krabbendam, S; van Vliet, E A; Verdouw, P; Serruys, P; van Beusekom, H M M

    2000-01-01

    OBJECTIVE—To improve the biocompatibility of stents using a phosphorylcholine coated stent as a form of biomimicry.
INTERVENTIONS—Implantation of phosphorylcholine coated (n = 20) and non-coated (n = 21) stents was performed in the coronary arteries of 25 pigs. The animals were killed after five days (n = 6), four weeks (n = 7), and 12 weeks (n = 8), and the vessels harvested for histology, scanning electron microscopy, and morphometry.
MAIN OUTCOME MEASURES—Stent performance was assessed by studying early endothelialisation, neointima formation, and vessel wall reaction to the synthetic coating.
RESULTS—Stent thrombosis did not occur in either group. Morphometry showed no significant differences between the two study groups at any time point. At five days both the coated and non-coated stents were equally well endothelialised (91% v 92%, respectively). At four and 12 weeks there was no difference in intimal thickness between the coated and non-coated stents. Up to 12 weeks postimplant the phosphorylcholine coating was still discernible in the stent strut voids, and did not appear to elicit an adverse inflammatory response.
CONCLUSION—In this animal model the phosphorylcholine coating showed excellent blood and tissue compatibility, unlike a number of other polymers tested in a similar setting. Given that the coating was present up to 12 weeks postimplant with no adverse tissue reaction, it may be a potential candidate polymer for local drug delivery.


Keywords: phosphorylcholine; stents; coatings; biocompatible materials PMID:10677417

  10. A Novel Attempt to Standardize Results of CFD Simulations Basing on Spatial Configuration of Aortic Stent-Grafts.

    PubMed

    Polanczyk, Andrzej; Podyma, Marek; Trebinski, Lukasz; Chrzastek, Jaroslaw; Zbicinski, Ireneusz; Stefanczyk, Ludomir

    2016-01-01

    Currently, studies connected with Computational Fluid Dynamic (CFD) techniques focus on assessing hemodynamic of blood flow in vessels in different conditions e.g. after stent-graft's placement. The paper propose a novel method of standardization of results obtained from calculations of stent-grafts' "pushing forces" (cumulative WSS--Wall Shear Stress), and describes its usefulness in diagnostic process. AngioCT data from 27 patients were used to reconstruct 3D geometries of stent-grafts which next were used to create respective reference cylinders. We made an assumption that both the side surface and the height of a stent-graft and a reference cylinder were equal. The proposed algorithm in conjunction with a stent-graft "pushing forces" on an implant wall, allowed us to determine which spatial configuration of a stent-graft predispose to the higher risk of its migration. For stent-grafts close to cylindrical shape (shape factor φ close to 1) WSS value was about 267 Pa, while for stent-grafts different from cylindrical shape (φ close to 2) WSS value was about 635 Pa. It was also noticed that deformation in the stent-graft's bifurcation part impaired blood flow hemodynamic. Concluding the proposed algorithm of standardization proved its usefulness in estimating the WSS values that may be useful in diagnostic process. Angular bends or tortuosity in bifurcations of an aortic implant should be considered in further studies of estimation of the risk of implantation failure.

  11. A Novel Attempt to Standardize Results of CFD Simulations Basing on Spatial Configuration of Aortic Stent-Grafts

    PubMed Central

    Polanczyk, Andrzej; Podyma, Marek; Trebinski, Lukasz; Chrzastek, Jaroslaw; Zbicinski, Ireneusz; Stefanczyk, Ludomir

    2016-01-01

    Currently, studies connected with Computational Fluid Dynamic (CFD) techniques focus on assessing hemodynamic of blood flow in vessels in different conditions e.g. after stent-graft’s placement. The paper propose a novel method of standardization of results obtained from calculations of stent-grafts' “pushing forces” (cumulative WSS—Wall Shear Stress), and describes its usefulness in diagnostic process. AngioCT data from 27 patients were used to reconstruct 3D geometries of stent-grafts which next were used to create respective reference cylinders. We made an assumption that both the side surface and the height of a stent-graft and a reference cylinder were equal. The proposed algorithm in conjunction with a stent-graft “pushing forces” on an implant wall, allowed us to determine which spatial configuration of a stent-graft predispose to the higher risk of its migration. For stent-grafts close to cylindrical shape (shape factor φ close to 1) WSS value was about 267Pa, while for stent-grafts different from cylindrical shape (φ close to 2) WSS value was about 635Pa. It was also noticed that deformation in the stent-graft’s bifurcation part impaired blood flow hemodynamic. Concluding the proposed algorithm of standardization proved its usefulness in estimating the WSS values that may be useful in diagnostic process. Angular bends or tortuosity in bifurcations of an aortic implant should be considered in further studies of estimation of the risk of implantation failure. PMID:27073907

  12. Endovascular Gene Delivery from a Stent Platform: Gene- Eluting Stents

    PubMed Central

    Fishbein, Ilia; Chorny, Michael; Adamo, Richard F; Forbes, Scott P; Corrales, Ricardo A; Alferiev, Ivan S; Levy, Robert J

    2015-01-01

    A synergistic impact of research in the fields of post-angioplasty restenosis, drug-eluting stents and vascular gene therapy over the past 15 years has shaped the concept of gene-eluting stents. Gene-eluting stents hold promise of overcoming some biological and technical problems inherent to drug-eluting stent technology. As the field of gene-eluting stents matures it becomes evident that all three main design modules of a gene-eluting stent: a therapeutic transgene, a vector and a delivery system are equally important for accomplishing sustained inhibition of neointimal formation in arteries treated with gene delivery stents. This review summarizes prior work on stent-based gene delivery and discusses the main optimization strategies required to move the field of gene-eluting stents to clinical translation. PMID:26225356

  13. Fenestrated Stent Graft Repair of Abdominal Aortic Aneurysm: Hemodynamic Analysis of the Effect of Fenestrated Stents on the Renal Arteries

    PubMed Central

    Chaichana, Thanapong

    2010-01-01

    Objective We wanted to investigate the hemodynamic effect of fenestrated stents on the renal arteries with using a fluid structure interaction method. Materials and Methods Two representative patients who each had abdominal aortic aneurysm that was treated with fenestrated stent grafts were selected for the study. 3D realistic aorta models for the main artery branches and aneurysm were generated based on the multislice CT scans from two patients with different aortic geometries. The simulated fenestrated stents were designed and modelled based on the 3D intraluminal appearance, and these were placed inside the renal artery with an intra-aortic protrusion of 5.0-7.0 mm to reflect the actual patients' treatment. The stent wire thickness was simulated with a diameter of 0.4 mm and hemodynamic analysis was performed at different cardiac cycles. Results Our results showed that the effect of the fenestrated stent wires on the renal blood flow was minimal because the flow velocity was not significantly affected when compared to that calculated at pre-stent graft implantation, and this was despite the presence of recirculation patterns at the proximal part of the renal arteries. The wall pressure was found to be significantly decreased after fenestration, yet no significant change of the wall shear stress was noticed at post-fenestration, although the wall shear stress was shown to decrease slightly at the proximal aneurysm necks. Conclusion Our analysis demonstrates that the hemodynamic effect of fenestrated renal stents on the renal arteries is insignificant. Further studies are needed to investigate the effect of different lengths of stent protrusion with variable stent thicknesses on the renal blood flow, and this is valuable for understanding the long-term outcomes of fenestrated repair. PMID:20046500

  14. 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

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

    SciTech Connect

    Gutzeit, A. Zollikofer, Ch. L. Dettling-Pizzolato, M.; Graf, N.; Largiader, J.; Binkert, C. A.

    2011-06-15

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

  16. Late Migration of Two Covered Biliary Stents Through a Spontaneous Bilioenteric Fistula in a Patient with Malignant Biliary Obstruction

    SciTech Connect

    Krokidis, Miltiadis E.; Hatzidakis, Adam A. Manousaki, Eirini G.; Gourtsoyiannis, Nicholas C.

    2008-01-15

    We report a case of simultaneous late migration of two ePTFE-FEP covered biliary endoprostheses (Viabil, W.L. Gore, Flagstaff, AZ, USA) that were percutaneously implanted for the treatment of malignant obstructive jaundice. The first Viabil covered stent was placed successfully without any evidence of dislocation or other complication during follow-up. Occlusion of the stent occurred 4 months later and was treated with the placement of a second stent of the same type. Thirteen months later the patient became symptomatic. Percutaneous transhepatic cholangiography (PTC) revealed the presence of a choledocho-duodenal fistula and the disappearance of the two endoprostheses previously implanted. A third metallic stent was then percutaneously positioned through the bilioenteric fistula. The computed tomography scan that followed for the detection of the metallic bodies did not reveal the dislocated metallic stents. Stent migration is a well-known complication of uncovered metallic stents, though Viabil stent migration is assumed to be most unlikely to happen due to the stent's anchoring barbs. Furthermore, the stent had already been tightly fixed by tumor over- and ingrowth, as recognized in previous imaging. This is a very unusual case, describing the disappearance of two metallic foreign bodies encapsulated by tumor.

  17. Self-Expanding Nitinol Renal Artery Stents: Comparison of Safety and Efficacy of Bare Versus Polyzene-F Nanocoated Stents in a Porcine Model

    SciTech Connect

    Kurz, P.; Stampfl, U.; Christoph, P.; Henn, C.; Satzl, S.; Radeleff, B.; Berger, I.; Richter, G. M.

    2011-02-15

    Objective: To investigate the safety and efficacy of a Polyzene-F nanocoat on new low-profile self-expandable nitinol stents in minipig renal arteries. Materials and Methods: Ten bare nitinol stents (BNS) and 10 stents coated with a 50 nm-thin Polyzene-F coating were randomly implanted into renal arteries of 10 minipigs (4- and 12-week follow-up, 5 animals/group). Thrombogenicity, on-stent surface endothelialization, vessel wall injury, late in-stent stenosis, and peristrut vessel wall inflammation were determined by quantitative angiography and postmortem histomorphometry. Results: In 6 of 10 BNS, >50% stenosis was found, but no stenosis was found in stents with a nanothin Polyzene-F coating. Histomorphometry showed a statistically significant (p < 0.05) different average maximum luminal loss of 55.16% {+-} 8.43% at 12 weeks in BNS versus 39.77% {+-} 7.41% in stents with a nanothin Polyzene-F coating. Stents with a nanothin Polyzene-F coating had a significantly (p < 0.05) lower inflammation score after 12 weeks, 1.31 {+-} 1.17 versus 2.17 {+-} 0.85 in BNS. The results for vessel wall injury (0.6 {+-} 0.58 for Polyzene-F-coated stents; 0.72 {+-} 0.98 for BNS) and re-endothelialization, (1.16 {+-} 0.43 and 1.23 {+-} 0.54, respectively) were not statistically significant at 12-week follow-up. No thrombus deposition was observed on the stents at either follow-up time point. Conclusion: Nitinol stents with a nanothin Polyzene-F coating successfully decreased in-stent stenosis and vessel wall inflammation compared with BNS. Endothelialization and vessel wall injury were found to be equal. These studies warrant long-term pig studies ({>=}120 days) because 12 weeks may not be sufficient time for complete healing; thereafter, human studies may be warranted.

  18. Juxtarenal Modular Aortic Stent Graft Infection Caused by Staphylococcus aureus

    PubMed Central

    Novotný, Róbert; Mitáš, Petr; Hlubocký, Jaroslav; Hrubý, Ján; Slautin, Andrey; Špunda, Rudolf; Lindner, Jaroslav

    2016-01-01

    Introduction. We are presenting a case report of an infected modular abdominal stent graft. Case Presentation. A 67-year-old male patient three years after Cook's modular abdominal aortic aneurysm (AAA) graft implantation for juxtarenal AAA with an implantation of a stent extension into the right common iliac artery for type Ib endoleak. The patient was admitted into our center in severe condition with suspected retroperitoneal bleeding. Computed tomography angiography (CTAG) confirmed retroperitoneal bleeding in the right common iliac artery. An urgent surgical revision was indicated; destructed arterial wall around the stent extension in the right common iliac artery was discovered. Due to the severe state of health of the patient, a resection of the infected stent and affected arterial wall was performed, followed by an iliac-femoral crossover bypass. The patient was transported to the intensive care unit with hepatic and renal failure, with maximal catecholamine support. Combined antibiotic treatment was started. The patient died five hours after the procedure. The cause of death was multiorgan failure caused by sepsis. Hemocultures and perioperative microbiological cultures showed the infection agent to be Staphylococcus aureus methicillin sensitive. Conclusion. Stent graft infection is a rare complication. Treatment is associated with high mortality and morbidity. PMID:26904354

  19. In vivo biocompatibility of a plasma-activated, coronary stent coating.

    PubMed

    Waterhouse, Anna; Wise, Steven G; Yin, Yongbai; Wu, Buchu; James, Barbara; Zreiqat, Hala; McKenzie, David R; Bao, Shisan; Weiss, Anthony S; Ng, Martin K C; Bilek, Marcela M M

    2012-11-01

    Bare metal and drug-eluting coronary stents suffer an inherent lack of vascular cell and blood compatibility resulting in adverse patient responses. We have developed a plasma-activated coating (PAC) for metallic coronary stents that is durable, withstands crimping and expansion, has low thrombogenicity and can covalently bind proteins, linker-free. This has been shown to enhance endothelial cell interactions in vitro and has the potential to promote biointegration of stents. Using the rabbit denuded iliac artery model, we show for the first time that PAC is a feasible coating for coronary stents in vivo. The coating integrity of PAC was maintained following implantation and expansion. The rate of endothelialization, strut coverage, neointimal response and the initial immune response were equivalent to bare metal stents. Furthermore, the initial thrombogenicity caused by the PAC stents showed a reduced trend compared to bare metal stents. This work demonstrates a robust, durable, non-cytotoxic plasma-based coating technology that has the ability to covalently immobilize bioactive molecules for surface modification of coronary stents. Improvements in the clinical performance of implantable cardiovascular devices could be achieved by the immobilization of proteins or peptides that trigger desirable cellular responses.

  20. Spectral Imaging for Intracranial Stents and Stent Lumen

    PubMed Central

    Chen, David Yen-Ting; Chen, Chi-Jen; Hsu, Hui-Ling

    2016-01-01

    Introduction Application of computed tomography for monitoring intracranial stents is limited because of stent-related artifacts. Our purpose was to evaluate the effect of gemstone spectral imaging on the intracranial stent and stent lumen. Materials and Methods In vitro, we scanned Enterprise stent phantom and a stent–cheese complex using the gemstone spectral imaging protocol. Follow-up gemstone spectral images of 15 consecutive patients with placement of Enterprise from January 2013 to September 2014 were also retrospectively reviewed. We used 70-keV, 140-keV, iodine (water), iodine (calcium), and iodine (hydroxyapatite) images to evaluate their effect on the intracranial stent and stent lumen. Two regions of interest were individually placed in stent lumen and adjacent brain tissue. Contrast-to-noise ratio was measured to determine image quality. The maximal diameter of stent markers was also measured to evaluate stent-related artifact. Two radiologists independently graded the visibility of the lumen at the maker location by using a 4-point scale. The mean of grading score, contrast/noise ratio and maximal diameter of stent markers were compared among all modes. All results were analyzed by SPSS version 20. Results In vitro, iodine (water) images decreased metallic artifact of stent makers to the greatest degree. The most areas of cheese were observed on iodine (water) images. In vivo, iodine (water) images had the smallest average diameter of stent markers (0.33 ± 0.17mm; P < .05) and showed the highest mean grading score (2.94 ± 0.94; P < .05) and contrast/noise ratio of in-stent lumen (160.03 ±37.79; P < .05) among all the modes. Conclusion Iodine (water) images can help reduce stent-related artifacts of Enterprise and enhance contrast of in-stent lumen. Spectral imaging may be considered a noninvasive modality for following-up patients with in-stent stenosis. PMID:26731534

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

    SciTech Connect

    Stefanczyk, Ludomir; Czeczotka, Jaroslaw; Elgalal, Marcin; Sapieha, Michal; Rowinski, Olgierd

    2011-02-15

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

  2. Influence of metal alloy and the profile of coronary stents in patients with multivessel coronary disease

    PubMed Central

    Maurício de Abreu Filho, Luciano; da Cruz Forte, Antonio Artur; Kiyoshi Sumita, Marcos; Favarato, Desidério; César Ximenes Meireles, George

    2011-01-01

    BACKGROUND: In Brazil, despite the recommendations of the Brazilian Society of Hemodynamics and Interventional Cardiology, the National Health System has not yet approved the use of drug-eluting stents. In percutaneous coronary interventions performed in the public and part of the private health care system, bare metal stents are used as the only option. Therefore, new information on bare metal stents is of great importance. The primary endpoint was to evaluate the influence of the alloy and the profile of coronary stents on late loss and restenosis rates 6 months after implantation in patients with multivessel coronary disease. METHODS: Single center, randomized and prospective study comparison of cobalt–chromium versus stainless steel stent implantation in 187 patients with multivessel coronary disease. At least one cobalt–chromium and one stainless steel stent were implanted per patient. RESULTS: Mean age of patients was 59.5±10.1 years with a prevalence of males (66.3%) and patients with acute coronary syndrome (56%). Baseline clinical characteristics were similar with hypertension in 146 (78%), dyslipidemia in 85 (45.5%) and diabetes in 68 (36.4%). Two hundred and twenty-nine cobalt–chromium and 284 stainless steel stents were implanted. Angiographic variables showed no statistically significant difference. Angiographic follow-up to 6 months after implantation showed similar late loss and restenosis rates. CONCLUSION: The use of two different alloys, stainless steel and cobalt–chrome stents, in the same patient and in the same vessel produced similar 6-month restenosis and late loss rates. PMID:21808863

  3. Drug-eluting stents to prevent stent thrombosis and restenosis.

    PubMed

    Im, Eui; Hong, Myeong-Ki

    2016-01-01

    Although first-generation drug-eluting stents (DES) have significantly reduced the risk of in-stent restenosis, they have also increased the long-term risk of stent thrombosis. This safety concern directly triggered the development of new generation DES, with innovations in stent platforms, polymers, and anti-proliferative drugs. Stent platform materials have evolved from stainless steel to cobalt or platinum-chromium alloys with an improved strut design. Drug-carrying polymers have become biocompatible or biodegradable and even polymer-free DES were introduced. New limus-family drugs (such as everolimus, zotarolimus or biolimus) were adopted to enhance stent performances. As a result, these new DES demonstrated superior vascular healing responses on intracoronary imaging studies and lower stent thrombotic events in actual patients. Recently, fully-bioresorbable stents (scaffolds) have been introduced, and expanding their applications. In this article, the important concepts and clinical results of new generation DES and bioresorbable scaffolds are described. PMID:26567863

  4. Drug-eluting stents to prevent stent thrombosis and restenosis.

    PubMed

    Im, Eui; Hong, Myeong-Ki

    2016-01-01

    Although first-generation drug-eluting stents (DES) have significantly reduced the risk of in-stent restenosis, they have also increased the long-term risk of stent thrombosis. This safety concern directly triggered the development of new generation DES, with innovations in stent platforms, polymers, and anti-proliferative drugs. Stent platform materials have evolved from stainless steel to cobalt or platinum-chromium alloys with an improved strut design. Drug-carrying polymers have become biocompatible or biodegradable and even polymer-free DES were introduced. New limus-family drugs (such as everolimus, zotarolimus or biolimus) were adopted to enhance stent performances. As a result, these new DES demonstrated superior vascular healing responses on intracoronary imaging studies and lower stent thrombotic events in actual patients. Recently, fully-bioresorbable stents (scaffolds) have been introduced, and expanding their applications. In this article, the important concepts and clinical results of new generation DES and bioresorbable scaffolds are described.

  5. Biomedical engineering in design and application of nitinol stents with shape memory effect

    NASA Astrophysics Data System (ADS)

    Ryklina, E. P.; Khmelevskaya, I. Y.; Morozova, Tamara V.; Prokoshkin, S. D.

    1996-04-01

    Our studies in the field of endosurgery in collaboration with the physicians of the National Research Center of Surgery of the Academy of Medical Sciences are carried out beginning in 1983. These studies laid the foundation for the new direction of X-ray surgery--X-ray Nitinol stenting of vessels and tubular structures. X-ray nitinol stents are unique self-fixing shells based on the shape memory effect and superelasticity of nickel-titanium alloys self- reconstructed under human body temperature. Applied for stenting of arteries in cases of stenosis etc., bile ducts in cases of benign and malignant stenoses, digestive tract in cases of oesophageal cancer and cervical canal uterus in cases of postsurgical atresiss and strictures of uterine. The purpose of stenting is restoration of the shape of artery or tubular structure by a cylinder frame formation. The especially elaborated original method of stenting allows to avoid the traditional surgical operation, i.e. the stenting is performed without blood, narcosis and surgical knife. The stent to be implanted is transported into the affected zone through the puncture under the X-ray control. Clinical applications of X-ray endovascular stenting has been started in March 1984. During this period nearly 400 operations on stenting have been performed on femoral, iliac, brachio-cephalic, subclavian arteries, bile ducts, tracheas, digestive tract and cervical canal uterus.

  6. Biodegradable polymeric stents for vascular application in a porcine carotid artery model: English version.

    PubMed

    Kischkel, S; Grabow, N; Püschel, A; Erdle, B; Kabelitz, M; Martin, D P; Williams, S F; Bombor, I; Sternberg, K; Schmitz, K-P; Schareck, W; Bünger, C M

    Obwohl die Entwicklung biodegradierbarer Polymerstents in den letzten Jahren große Fortschritte gemacht hat, verbleiben entscheidende noch zu lösende Probleme bestehen. Veränderungen im Design und in der chemischen Zusammensetzung sollen die Eigenschaften biodegradierbarer Stents optimieren und ihre Schwächen beseitigen.Der neue PLLA/P4HB-Stent konnte erfolgreich endovaskulär in die A. carotis communis von 10 Landschweinen implantiert werden, bei vergleichbaren mechanischen Eigenschaften zu 316L-Metallstents als Kontrollgruppe. 4 Wochen nach Implantation erfolgte eine Angio-CT zur Stenosegradbestimmung. Es zeigten sich deutlich höhere Stenosegrade in der PLLA/P4HB-Stent-Gruppe (52,05 ± 5,80 %) gegenüber der Metall-Stent-Gruppe (35,65 ± 3,72 %). Durch die orale Gabe von Atorvastatin konnte der distale Stenosegrad nach NASCET in der PLLA/P4HB-Stent-Gruppe (39,81 ± 8,57 %) auf das Niveau der Metall-Stent-Gruppe (44,21 % ± 2,34) gesenkt werden.Der PLLA/P4HB-Stent stellt einen vielversprechenden Ansatz zur Lösung der bestehenden Probleme beim Einsatz permanenter Stents dar. Nur wenn sich ein Stent vollständig auflöst, ist eine Heilung im Sinne einer Restitutio ad integrum möglich.

  7. Computational fluid dynamic simulations of image-based stented coronary bifurcation models.

    PubMed

    Chiastra, Claudio; Morlacchi, Stefano; Gallo, Diego; Morbiducci, Umberto; Cárdenes, Rubén; Larrabide, Ignacio; Migliavacca, Francesco

    2013-07-01

    One of the relevant phenomenon associated with in-stent restenosis in coronary arteries is an altered haemodynamics in the stented region. Computational fluid dynamics (CFD) offers the possibility to investigate the haemodynamics at a level of detail not always accessible within experimental techniques. CFD can quantify and correlate the local haemodynamics structures which might lead to in-stent restenosis. The aim of this work is to study the fluid dynamics of realistic stented coronary artery models which replicate the complete clinical procedure of stent implantation. Two cases of pathologic left anterior descending coronary arteries with their bifurcations are reconstructed from computed tomography angiography and conventional coronary angiography images. Results of wall shear stress and relative residence time show that the wall regions more prone to the risk of restenosis are located next to stent struts, to the bifurcations and to the stent overlapping zone for both investigated cases. Considering a bulk flow analysis, helical flow structures are generated by the curvature of the zone upstream from the stent and by the bifurcation regions. Helical recirculating microstructures are also visible downstream from the stent struts. This study demonstrates the feasibility to virtually investigate the haemodynamics of patient-specific coronary bifurcation geometries.

  8. The influence of grain size on the ductility of micro-scale stainless steel stent struts.

    PubMed

    Murphy, B P; Cuddy, H; Harewood, F J; Connolley, T; McHugh, P E

    2006-01-01

    Vascular stents are used to restore blood flow in stenotic arteries, and at present the implantation of a stent is the preferred revascularisation method for treating coronary artery disease, as the introduction of drug eluting stents (DESs) has lead to a significant improvement in the clinical outcome of coronary stenting. However the mechanical limits of stents are being tested when they are deployed in severe cases. In this study we aimed to show (by a combination of experimental tests and crystal plasticity finite element models) that the ductility of stainless steel stent struts can be increased by optimising the grain structure within micro-scale stainless steel stent struts. The results of the study show that within the specimen size range 55 to 190 microm ductility was not dependent on the size of the stent strut when the grain size maximised. For values of the ratio of cross sectional area to characteristic grain length less than 1,000, ductility was at a minimum irrespective of specimen size. However, when the ratio of cross sectional area to characteristic grain length becomes greater than 1,000 an improvement in ductility occurs, reaching a plateau when the ratio approaches a value characteristic of bulk material properties. In conclusion the ductility of micro-scale stainless steel stent struts is sensitive to microstructure and can be improved by reducing the grain size.

  9. Nanomaterial coatings applied on stent surfaces.

    PubMed

    Bagheri, Mahsa; Mohammadi, Marzieh; Steele, Terry Wj; Ramezani, Mohammad

    2016-05-01

    The advent of percutaneous coronary intervention and intravascular stents has revolutionized the field of interventional cardiology. Nonetheless, in-stent restenosis, inflammation and late-stent thrombosis are the major obstacles with currently available stents. In order to enhance the hemocompatibility of stents, advances in the field of nanotechnology allow novel designs of nanoparticles and biomaterials toward localized drug/gene carriers or stent scaffolds. The current review focuses on promising polymers used in the fabrication of newer generations of stents with a short synopsis on atherosclerosis and current commercialized stents, nanotechnology's impact on stent development and recent advancements in stent biomaterials is discussed in context.

  10. Medical implants and methods of making medical implants

    SciTech Connect

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

    2014-09-16

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

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

    PubMed Central

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

    2015-01-01

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

  12. Effect of force-induced mechanical stress at the coronary artery bifurcation stenting: Relation to in-stent restenosis

    NASA Astrophysics Data System (ADS)

    Lee, Cheng-Hung; Jhong, Guan-Heng; Hsu, Ming-Yi; Liu, Shih-Jung; Wang, Chao-Jan; Hung, Kuo-Chun

    2014-05-01

    The deployment of metallic stents during percutaneous coronary intervention has become common in the treatment of coronary bifurcation lesions. However, restenosis occurs mostly at the bifurcation area even in present era of drug-eluting stents. To achieve adequate deployment, physicians may unintentionally apply force to the strut of the stents through balloon, guiding catheters, or other devices. This force may deform the struts and impose excessive mechanical stresses on the arterial vessels, resulting in detrimental outcomes. This study investigated the relationship between the distribution of stress in a stent and bifurcation angle using finite element analysis. The unintentionally applied force following stent implantation was measured using a force sensor that was made in the laboratory. Geometrical information on the coronary arteries of 11 subjects was extracted from contrast-enhanced computed tomography scan data. The numerical results reveal that the application of force by physicians generated significantly higher mechanical stresses in the arterial bifurcation than in the proximal and distal parts of the stent (post hoc P < 0.01). The maximal stress on the vessels was significantly higher at bifurcation angle <70° than at angle ≧70° (P < 0.05). The maximal stress on the vessels was negatively correlated with bifurcation angle (P < 0.01). Stresses at the bifurcation ostium may cause arterial wall injury and restenosis, especially at small bifurcation angles. These finding highlight the effect of force-induced mechanical stress at coronary artery bifurcation stenting, and potential mechanisms of in-stent restenosis, along with their relationship with bifurcation angle.

  13. Effect of force-induced mechanical stress at the coronary artery bifurcation stenting: Relation to in-stent restenosis

    SciTech Connect

    Lee, Cheng-Hung; Jhong, Guan-Heng; Hsu, Ming-Yi; Wang, Chao-Jan; Liu, Shih-Jung; Hung, Kuo-Chun

    2014-05-28

    The deployment of metallic stents during percutaneous coronary intervention has become common in the treatment of coronary bifurcation lesions. However, restenosis occurs mostly at the bifurcation area even in present era of drug-eluting stents. To achieve adequate deployment, physicians may unintentionally apply force to the strut of the stents through balloon, guiding catheters, or other devices. This force may deform the struts and impose excessive mechanical stresses on the arterial vessels, resulting in detrimental outcomes. This study investigated the relationship between the distribution of stress in a stent and bifurcation angle using finite element analysis. The unintentionally applied force following stent implantation was measured using a force sensor that was made in the laboratory. Geometrical information on the coronary arteries of 11 subjects was extracted from contrast-enhanced computed tomography scan data. The numerical results reveal that the application of force by physicians generated significantly higher mechanical stresses in the arterial bifurcation than in the proximal and distal parts of the stent (post hoc P < 0.01). The maximal stress on the vessels was significantly higher at bifurcation angle <70° than at angle ≧70° (P < 0.05). The maximal stress on the vessels was negatively correlated with bifurcation angle (P < 0.01). Stresses at the bifurcation ostium may cause arterial wall injury and restenosis, especially at small bifurcation angles. These finding highlight the effect of force-induced mechanical stress at coronary artery bifurcation stenting, and potential mechanisms of in-stent restenosis, along with their relationship with bifurcation angle.

  14. Preventing in-stent restenosis using lipoprotein (a), lipid and cholesterol adsorbent materials.

    PubMed

    Kazemian, Mohammad Reza; Solouk, Atefeh; Tan, Aaron; Seifalian, Alexander M

    2015-12-01

    Atherosclerosis is one of the major cause of mortality in developed countries. The characteristic lesion of atherosclerosis is the atheroma or plaque that forms through thickening of the inner layer of the vessel wall (called the intima). The development of stent in 1980s revolutionised treatment of cardiovascular diseases, including atherosclerosis. However the advent of stenting was hindered by the new problem of in-stent restenosis. It was demonstrated that in-stent restenosis was the result of a new pathology in the form of neointimal hyperplasia, which was a maladaptive healing response to bare-metal stent implantation. Recent evidence suggests that although drug-eluting stent (DES) have reduced restenosis rates, important concerns have been raised regarding increased late stent thrombosis, myocardial infarction and death. With advances in nanotechnology and smart materials, covered stents has been proposed to overcome this problem. This is due to in-stent late restenosis and thromboses are mainly caused by smooth muscle cells (SMC) proliferation. Studies showed that there is a relation between high low-density lipoprotein (LDL) and lipoprotein (a) [Lp(a)] level in blood stream and chance of in-stent restenosis, moreover studies show that Lp(a) could stimulate SMC proliferation. We hypothesis development of covered stent with novel design and use of smart materials which could adsorb cholesterol and prevent contact between Lp(a) and vessel wall to overcome problem indicated in DES. In addition cost of stents will significantly reduce by elimination of drugs as well as complex manufacturing of the drug incorporation. PMID:26364047

  15. Preventing in-stent restenosis using lipoprotein (a), lipid and cholesterol adsorbent materials.

    PubMed

    Kazemian, Mohammad Reza; Solouk, Atefeh; Tan, Aaron; Seifalian, Alexander M

    2015-12-01

    Atherosclerosis is one of the major cause of mortality in developed countries. The characteristic lesion of atherosclerosis is the atheroma or plaque that forms through thickening of the inner layer of the vessel wall (called the intima). The development of stent in 1980s revolutionised treatment of cardiovascular diseases, including atherosclerosis. However the advent of stenting was hindered by the new problem of in-stent restenosis. It was demonstrated that in-stent restenosis was the result of a new pathology in the form of neointimal hyperplasia, which was a maladaptive healing response to bare-metal stent implantation. Recent evidence suggests that although drug-eluting stent (DES) have reduced restenosis rates, important concerns have been raised regarding increased late stent thrombosis, myocardial infarction and death. With advances in nanotechnology and smart materials, covered stents has been proposed to overcome this problem. This is due to in-stent late restenosis and thromboses are mainly caused by smooth muscle cells (SMC) proliferation. Studies showed that there is a relation between high low-density lipoprotein (LDL) and lipoprotein (a) [Lp(a)] level in blood stream and chance of in-stent restenosis, moreover studies show that Lp(a) could stimulate SMC proliferation. We hypothesis development of covered stent with novel design and use of smart materials which could adsorb cholesterol and prevent contact between Lp(a) and vessel wall to overcome problem indicated in DES. In addition cost of stents will significantly reduce by elimination of drugs as well as complex manufacturing of the drug incorporation.

  16. Endovascular Treatment of Multilevel Chronic Total Occlusion Using a Stent Puncture Technique in Buerger's Disease

    PubMed Central

    Lee, Jung-Hee; Ko, Young-Guk

    2016-01-01

    We reported a patient with Buerger's disease who presented with critical limb ischemiawith prior recurrent occlusions after multiple surgical and endovascular treatments. Total occlusion of the whole native femoropopliteal and infrapopliteal arteries was observed. The femoropopliteal bypass graft, as well as a stent that was implanted in the mid-popliteal artery, were also occluded. Because of the lack of distal targets for bypass, surgical revascularization was not feasible; therefore, we decided to perform endovascular treatment. To overcome the limitation of vascular access, the previously implanted popliteal stent was directly punctured, and a guide wire was passed through the bypass graft. After the organized thrombus in the bypass graft was aspirated, further recanalization below the popliteal stent down to the plantar arteries was performed successfully. In conclusion, the stent puncture technique is a feasible and safe option for overcoming the limitations of vascular access in patients with multilevel occlusions. PMID:27275180

  17. [Urethral stent to treat a refractory traumatic urethra stricture in a male hunting dog].

    PubMed

    Vogt, S; Schneider, M; Peppler, C; Günther, C; Kramer, M

    2014-01-01

    In a 1.5-year-old male hunting dog, a urethral defect distal to the pelvic flexure and the resulting urethral fistula were treated with a mucosal graft and a transurethral catheter. Six months postoperatively a stricture of the urethra occurred. Following balloon dilatation, urination was normal. One month after dilatation, urethral narrowing relapsed and was treated using a combination of balloon dilatation and urethral stent implantation. Ten months following stent implantation the dog continued to show normal urination, although a deformation of the proximal part of the stent was diagnosed radiographically. During the 1-year follow-up no additional complications were observed. In the future, urethral stents may replace surgical resection of the narrowed urethral region and re-anastomosis of the urethra.

  18. Which spring is the best? Comparison of methods for virtual stenting.

    PubMed

    Spranger, Katerina; Ventikos, Yiannis

    2014-07-01

    This paper presents a methodology for modeling the deployment of implantable devices used in minimally invasive vascular interventions. Motivated by the clinical need to perform preinterventional rehearsals of a stent deployment, we have developed methods enabling virtual device placement inside arteries, under the constraint of real-time application. This requirement of rapid execution narrowed down the search for a suitable method to the concept of a dynamic mesh. Inspired by the idea of a mesh of springs, we have found a novel way to apply it to stent modeling. The experiments conducted in this paper investigate properties of the stent models based on three different spring types: lineal, semitorsional, and torsional springs. Furthermore, this paper compares the results of various deployment scenarios for two different classes of devices: a stent graft and a flow diverter. The presented results can be of a high-potential clinical value, enabling the predictive evaluation of the outcome of a stent deployment treatment.

  19. Radiation dose from a phosphorous-32 impregnated wire mesh vascular stent.

    PubMed

    Janicki, C; Duggan, D M; Coffey, C W; Fischell, D R; Fischell, T A

    1997-03-01

    The near field dose distribution of a realistic vascular stent impregnated with radioactive 32P is calculated employing the dose-point-kernel (DPK) method in a homogeneous and uniform medium. The cylindrical wire mesh geometry for the Palmaz-Schatz [Palmaz-Schatz is a tradename of Cordis (a Johnson & Johnson company)] stent is incorporated in the model calculation, and the dose distribution generated by the beta particles emitted from the decayed radioactive 32P is computed at distances ranging from 0.1 to 2 mm exterior to the stent surface. Dose measurements were obtained using radiochromic film dosimetry media on an actual Palmaz-Schatz half-stent impregnated with 32P using ion implantation, and compared to the DPK model predictions. The close agreement between the model calculation and the film dosimetry data confirms the validity of the model which can be adapted to a variety of different stent designs.

  20. Acute Cholecystitis Caused by Malignant Cystic Duct Obstruction: Treatment with Metallic Stent Placement

    SciTech Connect

    Miyayama, Shiro Yamashiro, Masashi; Takeda, Taro; Aburano, Hiroyuki; Komatsu, Tetsuya; Sanada, Taku; Kosaka, Shotaro; Toya, Daisyu; Matsui, Osamu

    2008-07-15

    We report the successful management of acute cholecystitis using cystic duct stent placement in 3 patients with inoperable malignant cystic duct obstruction (2 cholangiocarcinoma and 1 pancreatic carcinoma). All patients underwent stent placement in the bile duct, using an uncovered stent in 2 and a covered stent in 1, to relieve jaundice occurring 8-184 days (mean 120 days) before the development of acute cholecystitis. The occluded cystic duct was traversed by a microcatheter and a stent was implanted 4-17 days (mean 12 days) after cholecystostomy. Acute cholecystitis was improved after the procedure in all patients. Two patients died 3 and 10 months later, while 1 has survived without cholecystitis for 22 months after the procedure to date.

  1. Fully Biodegradable Airway Stents Using Amino Alcohol-Based Poly(ester amide) Elastomers

    PubMed Central

    Wang, Jane; Boutin, Kyle G.; Abdulhadi, Omar; Personnat, Lyndia D.; Shazly, Tarek; Langer, Robert; Channick, Colleen L.; Borenstein, Jeffrey T.

    2014-01-01

    Airway stents are often used to maintain patency of the tracheal and bronchial passages in patients suffering from central airway obstruction caused by malignant tumors, scarring, and injury. Like most conventional medical implants, they are designed to perform their functions for a limited period of time, after which surgical removal is often required. Two primary types of airway stents are in general use, metal mesh devices and elastomeric tubes; both are constructed using permanent materials, and must be removed when no longer needed, leading to potential complications. This paper describes the development of process technologies for bioresorbable prototype elastomeric airway stents that would dissolve completely after a predetermined period of time or by an enzymatic triggering mechanism. These airway stents are constructed from biodegradable elastomers with high mechanical strength, flexibility and optical transparency. This work combines microfabrication technology with bioresorbable polymers, with the ultimate goal of a fully biodegradable airway stent ultimately capable of improving patient safety and treatment outcomes. PMID:23526787

  2. Successful Treatment with a Covered Stent and 6-Year Follow-Up of Biliary Complication After Liver Transplantation

    SciTech Connect

    Doros, Attila Nemeth, Andrea; Deak, Akos Pal; Hartmann, Erika; Gerlei, Zsuzsa; Fazakas, Janos; Kobori, Laszlo

    2010-04-15

    The role of covered stent in the management of biliary complications is not yet defined in liver transplant recipients. This Case Report presents a patient with anastomotic stricture and leakage with biloma treated with a covered stent 32 months following liver transplantation. Signs of in-stent restenosis developed 52 months following covered stent placement, which was resolved by balloon dilation. There were no complications during the interventions. The latest follow-up, at 69 months following primary and 19 months following secondary percutaneous intervention, shows a patent covered stent without any clinical or morphological sign of further restenosis. The clinical success with long-term follow-up data suggests that covered stent implantation can be a rational, minimally invasive option for simultaneous treatment of bile duct stenosis and bile leak following liver transplantation in selected cases.

  3. Effects of the inlet conditions and blood models on accurate prediction of hemodynamics in the stented coronary arteries

    NASA Astrophysics Data System (ADS)

    Jiang, Yongfei; Zhang, Jun; Zhao, Wanhua

    2015-05-01

    Hemodynamics altered by stent implantation is well-known to be closely related to in-stent restenosis. Computational fluid dynamics (CFD) method has been used to investigate the hemodynamics in stented arteries in detail and help to analyze the performances of stents. In this study, blood models with Newtonian or non-Newtonian properties were numerically investigated for the hemodynamics at steady or pulsatile inlet conditions respectively employing CFD based on the finite volume method. The results showed that the blood model with non-Newtonian property decreased the area of low wall shear stress (WSS) compared with the blood model with Newtonian property and the magnitude of WSS varied with the magnitude and waveform of the inlet velocity. The study indicates that the inlet conditions and blood models are all important for accurately predicting the hemodynamics. This will be beneficial to estimate the performances of stents and also help clinicians to select the proper stents for the patients.

  4. Stent graft exclusion of a pseudoaneurysm in a Blalock-Taussig shunt.

    PubMed

    Sanchez-Recalde, Angel; Garzón, Gonzalo; Oliver, José M

    2010-08-01

    This case is the first report of slow-growing pseudoaneurysm after vessel dissection secondary to two stents implantation into classic Blalock Taussig shunt in a patient with pulmonary atresia and ventricular septal defect. Pseudoaneurysm was successfully excluded by a percutaneous approach with self-expandable stent graft deployment from the aorta to the middle of the Blalock Taussig shunt. Nearly 3 years after the procedure, the classic BT is patent, and there were no restenosis or thrombosis in spite of the very long length of the stented segment.

  5. Permanent Pacemaker-Induced Superior Vena Cava Syndrome: Successful Treatment by Endovascular Stent

    SciTech Connect

    Lanciego, Carlos Rodriguez, Mario; Rodriguez, Adela; Carbonell, Miguel A.; Garcia, Lorenzo Garcia

    2003-11-15

    The use of metallic stents in the management of benign and malignant superior vena cava syndrome (SVCS) is well documented. Symptomatic stenosis or occlusion of the SVC is a rare complication of a transvenous permanent pacemaker implant. Suggested treatments have included anticoagulation therapy, thrombolysis, balloon angioplasty and surgery. More recently, endovascular stenting has evolved as an attractive alternative but the data available in the literature are limited. We describe a case in which venous stenting with a Wallstent endoprosthesis was used successfully. The patient remains symptom free and with normal pacemaker function 36 months later.

  6. Fatigue behaviour of Nitinol peripheral stents: the role of plaque shape studied with computational structural analyses.

    PubMed

    Dordoni, Elena; Meoli, Alessio; Wu, Wei; Dubini, Gabriele; Migliavacca, Francesco; Pennati, Giancarlo; Petrini, Lorenza

    2014-07-01

    Fatigue resistance of Nitinol stents implanted into femoro-popliteal arteries is a critical issue for the particular biomechanical environment of this district. Hip and knee joint movements due to the cyclic daily activity expose the superficial femoral artery (SFA), and therefore the implanted stents, to quite large and cyclic deformations influencing stent fatigue resistance. Objective of this work is to provide a tool based on finite element analysis able to evaluate the biomechanical effect of SFA on stent fatigue resistance. Computer simulations of the treatment of stenotic vessel by angioplasty and stenting and of the subsequent in vivo loading conditions (axial compression and bending) were carried out. Three different stenotic vessel models were defined, by keeping a constant stenosis rate and changing the plaque sharpness and number of stenoses. The fatigue behaviour was analysed comparing the amplitude and mean value distribution of the first principal strain in the whole stent for the different simulated conditions. Results showed that the maximum mean strain is similar in all the models, while the alternating strain is related to both plaque shape and loading conditions. In conclusion, this study confirms the requisite of replicating in vivo loading conditions. It also reveals the importance of taking into account the thickness variation of the vessel in the stenotic zone in the assessment of the stent fatigue resistance.

  7. Sensor to detect endothelialization on an active coronary stent

    PubMed Central

    2010-01-01

    Background A serious complication with drug-eluting coronary stents is late thrombosis, caused by exposed stent struts not covered by endothelial cells in the healing process. Real-time detection of this healing process could guide physicians for more individualized anti-platelet therapy. Here we present work towards developing a sensor to detect this healing process. Sensors on several stent struts could give information about the heterogeneity of healing across the stent. Methods A piezoelectric microcantilever was insulated with parylene and demonstrated as an endothelialization detector for incorporation within an active coronary stent. After initial characterization, endothelial cells were plated onto the cantilever surface. After they attached to the surface, they caused an increase in mass, and thus a decrease in the resonant frequencies of the cantilever. This shift was then detected electrically with an LCR meter. The self-sensing, self-actuating cantilever does not require an external, optical detection system, thus allowing for implanted applications. Results A cell density of 1300 cells/mm2 on the cantilever surface is detected. Conclusions We have developed a self-actuating, self-sensing device for detecting the presence of endothelial cells on a surface. The device is biocompatible and functions reliably in ionic liquids, making it appropriate for implantable applications. This sensor can be placed along the struts of a coronary stent to detect when the struts have been covered with a layer of endothelial cells and are no longer available surfaces for clot formation. Anti-platelet therapy can be adjusted in real-time with respect to a patient's level of healing and hemorrhaging risks. PMID:21050471

  8. Metallic stent and flexible bronchoscopy without fluoroscopy for acute respiratory failure.

    PubMed

    Lin, S-M; Lin, T-Y; Chou, C-L; Chen, H-C; Liu, C-Y; Wang, C-H; Lin, H-C; Yu, C-T; Lee, K-Y; Kuo, H-P

    2008-05-01

    Stent implantation has been reported to facilitate liberation from mechanical ventilation in patients with respiratory failure due to central airway disease. The present retrospective cohort study sought to evaluate the risk and benefit of stent implantation via bronchoscopy without fluoroscopic guidance in mechanically ventilated patients. From July 2001 to September 2006, 26 patients with acute respiratory failure were recruited. A bronchoscope was inserted through a mouth guard into the space between the tracheal wall and the endotracheal tube. A guide wire was inserted via the flexible bronchoscope to the lesion site. The bronchoscope was reintroduced through the endotracheal tube. Under bronchoscopic visualisation, the delivery catheter was advanced over the guide wire to deploy the stent. These procedures were successfully performed in 26 patients, with 22 stents placed in the trachea and seven in the main bronchus. Of the 26 patients, 14 (53.8%) became ventilator independent during their stay in the intensive care unit. Severe pneumonia was the most common cause, in seven (58.3%) out of 12 patients, for continued ventilator dependence after stenting. Granulation tissue formation was found in seven patients during the follow-up period. It is concluded that metallic stents can be safely implanted without fluoroscopic guidance in patients with respiratory failure, to facilitate ventilator independence.

  9. Percutaneous Management of a Coronary Bifurcation Aneurysm with Mesh-Covered Stents and the Simultaneous Kissing Stent Technique.

    PubMed

    Crimi, Gabriele; Bartolini, Davide; Bellotti, Sandro; Iannone, Alessandro; Rubartelli, Paolo

    2015-08-01

    A 63-year-old man was admitted with a clinical diagnosis of acute coronary syndrome (non-ST-segment elevation), characterized by regional hypokinesia of the left ventricular posterior and lateral walls and by positive cardiac biomarkers. The coronary angiogram showed a 12.5-mm-diameter aneurysm with a mural thrombus and possible distal embolism to the bifurcation of the left circumflex coronary artery and the 2nd marginal branch. The aneurysm was managed percutaneously by implanting 2 mesh-covered stents in accordance with the "simultaneous kissing stent" technique. Follow-up angiography and optical coherence tomography at 5 postprocedural months documented complete sealing of the aneurysm and diffuse in-stent restenosis. No sign of ischemia occurred during the subsequent follow-up.

  10. Drug-Eluting or Bare-Metal Stents for Coronary Artery Disease.

    PubMed

    Bønaa, Kaare H; Mannsverk, Jan; Wiseth, Rune; Aaberge, Lars; Myreng, Yngvar; Nygård, Ottar; Nilsen, Dennis W; Kløw, Nils-Einar; Uchto, Michael; Trovik, Thor; Bendz, Bjørn; Stavnes, Sindre; Bjørnerheim, Reidar; Larsen, Alf-Inge; Slette, Morten; Steigen, Terje; Jakobsen, Ole J; Bleie, Øyvind; Fossum, Eigil; Hanssen, Tove A; Dahl-Eriksen, Øystein; Njølstad, Inger; Rasmussen, Knut; Wilsgaard, Tom; Nordrehaug, Jan E

    2016-09-29

    Background Limited data are available on the long-term effects of contemporary drug-eluting stents versus contemporary bare-metal stents on rates of death, myocardial infarction, repeat revascularization, and stent thrombosis and on quality of life. Methods We randomly assigned 9013 patients who had stable or unstable coronary artery disease to undergo percutaneous coronary intervention (PCI) with the implantation of either contemporary drug-eluting stents or bare-metal stents. In the group receiving drug-eluting stents, 96% of the patients received either everolimus- or zotarolimus-eluting stents. The primary outcome was a composite of death from any cause and nonfatal spontaneous myocardial infarction after a median of 5 years of follow-up. Secondary outcomes included repeat revascularization, stent thrombosis, and quality of life. Results At 6 years, the rates of the primary outcome were 16.6% in the group receiving drug-eluting stents and 17.1% in the group receiving bare-metal stents (hazard ratio, 0.98; 95% confidence interval [CI], 0.88 to 1.09; P=0.66). There were no significant between-group differences in the components of the primary outcome. The 6-year rates of any repeat revascularization were 16.5% in the group receiving drug-eluting stents and 19.8% in the group receiving bare-metal stents (hazard ratio, 0.76; 95% CI, 0.69 to 0.85; P<0.001); the rates of definite stent thrombosis were 0.8% and 1.2%, respectively (P=0.0498). Quality-of-life measures did not differ significantly between the two groups. Conclusions In patients undergoing PCI, there were no significant differences between those receiving drug-eluting stents and those receiving bare-metal stents in the composite outcome of death from any cause and nonfatal spontaneous myocardial infarction. Rates of repeat revascularization were lower in the group receiving drug-eluting stents. (Funded by the Norwegian Research Council and others; NORSTENT ClinicalTrials.gov number, NCT00811772 .).

  11. Biodegradable stents with elastic memory.

    PubMed

    Venkatraman, Subbu S; Tan, Lay Poh; Joso, Joe Ferry D; Boey, Yin Chiang Freddy; Wang, Xintong

    2006-03-01

    This work reports, for the first time, the development of a fully biodegradable polymeric stent that can self-expand at body temperatures (approximately 37 degrees C), using the concept of elastic memory. This self-expansion is necessary in fully polymeric stents, to overcome the problem of elastic recoil following balloon expansion in a body vessel. Bi-layered biodegradable stent prototypes were produced from poly-L-lactic acid (PLLA) and poly glycolic acid (PLGA) polymers. Elastic memory was imparted to the stents by temperature conditioning. The thickness and composition of each layer in the stents are critical parameters that affect the rate of self-expansion at 37 degrees C, as well as the collapse strengths of the stents. The rate of self-expansion of the stents, as measured at 37 degrees C, exhibits a maximum with layer thickness. The Tg of the outer layer is another significant parameter that affects the overall rate of expansion.

  12. Vascular Response to Experimental Stent Malapposition and Under-Expansion.

    PubMed

    O'Brien, Caroline C; Lopes, Augusto C; Kolandaivelu, Kumaran; Kunio, Mie; Brown, Jonathan; Kolachalama, Vijaya B; Conway, Claire; Bailey, Lynn; Markham, Peter; Costa, Marco; Ware, James; Edelman, Elazer R

    2016-07-01

    Up to 80% of all endovascular stents have malapposed struts, and while some impose catastrophic events others are inconsequential. Thirteen stents were implanted in coronary arteries of seven healthy Yorkshire pigs, using specially-designed cuffed balloons inducing controlled stent malapposition and under-expansion. Optical coherence tomography (OCT) imaging confirmed that 25% of struts were malapposed (strut-wall distance stent cross-sectional areas (slope = 0.86, p < 0.0001, R (2) = 0.94). OCT in three of the most significantly malapposed vessels at baseline showed high correlation of elastic lamina area and lumen area (R (2) = 0.96) suggesting all lumen loss was related to contraction of elastic lamina with negligible plaque/intimal hyperplasia growth. Simulation showed this vascular recoil could be partially explained by the non-uniform strain environment created from sub-optimal expansion of device and balloon, and the inability of stent support in the malapposed region to resist recoil. Malapposition as a result of stent under-expansion is resolved acutely in healthy normal arteries, suggesting existing animal models are limited in replicating clinically observed persistent stent malapposition.

  13. Percutaneous Pulmonary Valve Implantation

    PubMed Central

    Lee, Hyoung-Doo

    2012-01-01

    Pulmonary regurgitation (PR) is a frequent sequelae after repair of tetralogy of Fallot, pulmonary atresia, truncus arteriosus, Rastelli and Ross operation. Due to patient growth and conduit degeneration, these conduits have to be changed frequently due to regurgitation or stenosis. However, morbidity is significant in these repeated operations. To prolong conduit longevity, bare-metal stenting in the right ventricular outflow tract (RVOT) obstruction has been performed. Stenting the RVOT can reduce the right ventricular pressure and symptomatic improvement, but it causes PR with detrimental effects on the right ventricle function and risks of arrhythmia. Percutaneous pulmonary valve implantation has been shown to be a safe and effective treatment for patients with pulmonary valve insufficiency, or stenotic RVOTs. PMID:23170091

  14. Biodegradable tocopherol acetate as a drug carrier to prevent ureteral stent-associated infection.

    PubMed

    Elayarajah; Rajendran, R; Venkatrajah; Sreekumar, Sweda; Sudhakar, Asa; Janiga; Sreekumar, Soumya

    2011-03-01

    Biomaterial-centred bacterial infections present common and challenging complications with medical implants like ureteral stent which provide substratum for the biofilm formation. Hence the purpose of this study is to make antibacterial stent surface with biodegradable polymer (tocopherol acetate) and anti-infective agents (norfloxacin and metronidazole) using a modified dip-coating procedure. This is done by impregnating the stent pieces in the anti-infective solution (a mixture of norfloxacin-metronidazole and polymer) for uniform surface coating (drug-carrier-coated stents). After coating, agar diffusion test was performed as qualitative test to find out the sensitivity of coated stents against the clinical isolates, Staphylococcus epidermidis and Escherichia coli. Quantitative test was measured by calculating the numbers of adhered bacteria on coated and uncoated stents by incubating the stent pieces in artificial urine. Difference in the number of viable bacteria adhered on the surface of coated and uncoated stents were statistically calculated using chi square test with p < 0.05 considered significant. The stent colonising ability of Staphylococcus epidermidis and Escherichia coli in a controlled environment chamber was determined using two-challenge dose of the isolates by in vitro challenge test. In qualitative test, the zone of inhibition around the coated stents showed sensitivity against the clinical isolates. In quantitative test, the number of adhered bacteria on the surface of coated stents was reduced to a significant level (p < 0.05). The polymer, tocopherol acetate is highly biodegradable in nature. Due to its degrading ability in body tissues, it releases the anti-infective drugs at a constant and sustained rate.

  15. A Polyhydroxybutyrate Biodegradable Stent: Preliminary Experience in the Rabbit

    SciTech Connect

    Unverdorben, M.; Spielberger, A.; Schywalsky, M.; Labahn, D.; Hartwig, S.; Schneider, M.; Degenhardt, R.; Schaldach, M.; Vallbracht, C.

    2002-03-15

    Purpose: The lifelong persistence of foreign bodies within the arteries may contribute to restenosis. Thus,biodegradable devices might decrease recurrence rates. Methods: Eleven polyhydroxybutyrate biodegradable stents and 13 tantalum stents were implanted into the iliac arteries of New Zealand white rabbits for up to 30 weeks. After killing the animals,the specimens were harvested, fixed in formalin, processed in paraffin,and stained. Results: Polyhydroxybutyrate instigated intense inflammatory and proliferative reactions with an increase in collagen (2.4- to 8-fold vs native segments), thrombosis and in-stentlumen narrowing (375.5-606.6 mm vs 655.6 {+-} 268.8 mm in native segments). The elastic membranes were destroyed in all specimens. The tantalum stents increased the in-stent lumen progressively (769.7 {+-} 366.6 mm vs 1309.9 {+-} 695.3 mm),penetrated the external elastic membrane, and increased mural collagen content (6- to 8.6-fold vs native segments). Neither restenoses nor thromboses occurred. Conclusions: In the rabbit iliacartery, polyhydroxybutyrate stents caused intensive inflammatory vascular reactions which ban them from clinical use.

  16. An analysis of the contact between the stent and the artery using tube hydroforming simulation.

    PubMed

    Araújo, Rogério; Guimarães, Tobias A; Oliveira, Sônia A G

    2013-11-01

    Stents for angioplasty have been extensively used to treat coronary diseases. The aim of this study is to analyze the expansion of the stent and the contact with the artery using tube hydroforming simulation. In the simulation, the contact stress and the final shape of the artery after stent expansion process using the Stampack (®;) software will be studied. A model of a commercial stent made of 316L stainless steel was modeled by using an elastic-plastic constitutive law with isotropic hardening. The artery was modeled as a cylinder and made of hyperelastic material. The stent model studied in this work presented a good performance according to the results obtained. After expansion, any region of the stent's structure with strong risk of wrinkling, thinning, or buckling was not observed. In the forming limit diagram, all points were far from the Keeler-Goodwin diagram. Furthermore, the expanded stent model has a good conformability. In conclusion, our data show that the proposed methodology is a useful tool to check if the stent model implanted in the artery may cause restenosis after angioplasty; thus, our tests provided a reliable tool to analyze this risk.

  17. Release of plasmid DNA from intravascular stents coated with ultrathin multilayered polyelectrolyte films.

    PubMed

    Jewell, Christopher M; Zhang, Jingtao; Fredin, Nathaniel J; Wolff, Matthew R; Hacker, Timothy A; Lynn, David M

    2006-09-01

    Materials that permit control over the release of DNA from the surfaces of topologically complex implantable devices, such as intravascular stents, could contribute to the development of new approaches to the localized delivery of DNA. We report the fabrication of ultrathin, multilayered polyelectrolyte films that permit both the immobilization and controlled release of plasmid DNA from the surfaces of stainless steel intravascular stents. Our approach makes use of an aqueous-based, layer-by-layer method for the assembly of nanostructured thin films consisting of alternating layers of plasmid DNA and a hydrolytically degradable polyamine. Characterization of coated stents using scanning electron microscopy (SEM) demonstrated that stents were coated uniformly with an ultrathin film ca. 120 nm thick that adhered conformally to the surfaces of stent struts. These ultrathin films did not crack, peel, or delaminate substantially from the surface after exposure to a range of mechanical challenges representative of those encountered during stent deployment (e.g., balloon expansion). Stents coated with eight bilayers of degradable polyamine and a plasmid encoding enhanced green fluorescent protein (EGFP) sustained the release of DNA into solution for up to four days when incubated in phosphate buffered saline at 37 degrees C, and coated stents were capable of mediating the expression of EGFP in a mammalian cell line without the aid of additional transfection agents. The approach reported here could, with further development, contribute to the development of localized gene-based approaches to the treatment of cardiovascular diseases or related conditions. PMID:16961308

  18. Helical CT Angiography of Abdominal Aortic Aneurysms Treated with Suprarenal Stent Grafting: A Pictorial Essay

    SciTech Connect

    Sun Zhonghua

    2003-06-15

    The endovascular repair of abdominal aorticaneurysm (AAA) with stent grafts is rapidly becoming an important alternative to open repair. Suprarenal stent grafting, recently modified from conventional infrarenal stent grafting, is a technique for the purpose of treating patients with inappropriate aneurysm necks.Unlike open repair, the success of endoluminal repair cannot be ascertained by means of direct examination and thus relies on imaging results. The use of conventional angiography for arterial imaging has become less dominant, while helical computed tomography angiography(CTA) has become the imaging modality of choice for both preoperative assessment and postoperative followup after treatment with stent graft implants. There is an increasing likelihood that radiologists will become more and more involved in the procedure of aortic stent grafting and in giving the radiological report on these patients treated with stent grafts. It is necessary for radiologists to be familiar with the imaging findings, including common and uncommon appearances following aortic stent grafting. The purpose of this pictorial essay is to describe and present normal and abnormal imaging appearances following aortic stent grafting based on helical CTA.

  19. Uncertainty assessment of imaging techniques for the 3D reconstruction of stent geometry.

    PubMed

    Cosentino, Daria; Zwierzak, Iwona; Schievano, Silvia; Díaz-Zuccarini, Vanessa; Fenner, John W; Narracott, Andrew J

    2014-08-01

    This paper presents a quantitative assessment of uncertainty for the 3D reconstruction of stents. This study investigates a CP stent (Numed, USA) used in congenital heart disease applications with a focus on the variance in measurements of stent geometry. The stent was mounted on a model of patient implantation site geometry, reconstructed from magnetic resonance images, and imaged using micro-computed tomography (CT), conventional CT, biplane fluoroscopy and optical stereo-photogrammetry. Image data were post-processed to retrieve the 3D stent geometry. Stent strut length, separation angle and cell asymmetry were derived and repeatability was assessed for each technique along with variation in relation to μCT data, assumed to represent the gold standard. The results demonstrate the performance of biplanar reconstruction methods is comparable with volumetric CT scans in evaluating 3D stent geometry. Uncertainty on the evaluation of strut length, separation angle and cell asymmetry using biplanar fluoroscopy is of the order ±0.2mm, 3° and 0.03, respectively. These results support the use of biplanar fluoroscopy for in vivo measurement of 3D stent geometry and provide quantitative assessment of uncertainty in the measurement of geometric parameters.

  20. Patient-specific simulations of stenting procedures in coronary bifurcations: two clinical cases.

    PubMed

    Morlacchi, Stefano; Colleoni, Sebastian George; Cárdenes, Rubén; Chiastra, Claudio; Diez, Jose Luis; Larrabide, Ignacio; Migliavacca, Francesco

    2013-09-01

    Computational simulations of stenting procedures in idealized geometries can only provide general guidelines and their use in the patient-specific planning of percutaneous treatments is inadequate. Conversely, image-based patient-specific tools that are able to realistically simulate different interventional options might facilitate clinical decision-making and provide useful insights on the treatment for each individual patient. The aim of this work is the implementation of a patient-specific model that uses image-based reconstructions of coronary bifurcations and is able to replicate real stenting procedures following clinical indications. Two clinical cases are investigated focusing the attention on the open problems of coronary bifurcations and their main treatment, the provisional side branch approach. Image-based reconstructions are created combining the information from conventional coronary angiography and computed tomography angiography while structural finite element models are implemented to replicate the real procedure performed in the patients. First, numerical results show the biomechanical influence of stents deployment in the coronary bifurcations during and after the procedures. In particular, the straightening of the arterial wall and the influence of two overlapping stents on stress fields are investigated here. Results show that a sensible decrease of the vessel tortuosity occurs after stent implantation and that overlapping devices result in an increased stress state of both the artery and the stents. Lastly, the comparison between numerical and image-based post-stenting configurations proved the reliability of such models while replicating stent deployment in coronary arteries.

  1. The role of stents in the treatment of congenital heart disease: Current status and future perspectives

    PubMed Central

    Peters, Bjoern; Ewert, Peter; Berger, Felix

    2009-01-01

    Intravascular or intracardiac stenoses occur in many forms of congenital heart disease (CHD). Therefore, the implantation of stents has become an accepted interventional procedure for stenotic lesions in pediatric cardiology. Furthermore, stents are know to be used to exclude vessel aneurysm or to ensure patency of existing or newly created intracardiac communications. With the further refinement of the first generation of devices, a variety of “modern” stents with different design characteristics have evolved. Despite the tremendous technical improvement over the last 20 years, the “ideal stent” has not yet been developed. Therefore, the pediatric interventionalist has to decide which stent is suitable for each lesion. On this basis, currently available stents are discussed in regard to their advantages and disadvantages for common application in CHD. New concepts and designs developed to overcome some of the existing problems, like the failure of adaptation to somatic growth, are presented. Thus, in the future, biodegradable or growth stents might replace the currently used generation of stents. This might truly lead to widening indications for the use of stents in the treatment of CHD. PMID:20300265

  2. An analysis of the contact between the stent and the artery using tube hydroforming simulation.

    PubMed

    Araújo, Rogério; Guimarães, Tobias A; Oliveira, Sônia A G

    2013-11-01

    Stents for angioplasty have been extensively used to treat coronary diseases. The aim of this study is to analyze the expansion of the stent and the contact with the artery using tube hydroforming simulation. In the simulation, the contact stress and the final shape of the artery after stent expansion process using the Stampack (®;) software will be studied. A model of a commercial stent made of 316L stainless steel was modeled by using an elastic-plastic constitutive law with isotropic hardening. The artery was modeled as a cylinder and made of hyperelastic material. The stent model studied in this work presented a good performance according to the results obtained. After expansion, any region of the stent's structure with strong risk of wrinkling, thinning, or buckling was not observed. In the forming limit diagram, all points were far from the Keeler-Goodwin diagram. Furthermore, the expanded stent model has a good conformability. In conclusion, our data show that the proposed methodology is a useful tool to check if the stent model implanted in the artery may cause restenosis after angioplasty; thus, our tests provided a reliable tool to analyze this risk. PMID:23813983

  3. Clinical, angiographic and procedural characteristics of longitudinal stent deformation.

    PubMed

    Guler, A; Guler, Y; Acar, E; Aung, S M; Efe, S C; Kilicgedik, A; Karabay, C Y; Barutcu, S; Tigen, M K; Pala, S; İzgi, A; Esen, A M; Kirma, C

    2016-08-01

    Recently, longitudinal stent deformation (LSD) has been reported increasingly. Even though the reported cases included almost all stent designs, most cases were seen in the Element™ stent design (Boston Scientific, Natick, MA, USA). It is considered that stent design, lesion and procedural characteristics play a role in the etiology of LSD. Yet, the effect of LSD on long-term clinical outcomes has not been studied well. Element stents implanted between January 2013 and April 2015 in our hospital were examined retrospectively. Patients were grouped into two according to the presence of LSD, and their clinical, lesion and procedural characteristics were studied. Twenty-four LSD's were detected in 1812 Element stents deployed in 1314 patients (1.83 % of PCI cases and 1.32 % of all Element stents). LMCA lesions (16.7 % vs 1.6 %, p < 0.001), complex lesions (75 % vs 35.1 %, p < 0.001), bifurcation lesions (37.5 % vs 18.3 %, p = 0.017), ostial lesions (33.3 % vs 12.8 %, p = 0.003), using of extra-support guiding catheter (54.2 % vs 22.3 %, p < 0.001) and extra-support guidewire (37.5 % vs 16.2 %, p = 0.005) were found to be more frequent in cases with LSD than in cases without it. In addition, the number of stents, stent inflation pressure and the use of post-dilatation were significantly different between the two groups. Two patients had an adverse event during the follow-up period. LSD is a rarely encountered complication, and is more common in complex lesions such as ostial, bifurcation and LMCA lesions. The use of extra-support guiding catheter, extra-support guidewires and low stent inflation pressure increases the occurrence of LSD. Nevertheless, with increased awareness of LSD and proper treatment, unwanted long-term outcomes can be successfully prevented. PMID:27198891

  4. Overlap stenting for in-stent restenosis after carotid artery stenting

    PubMed Central

    Nishihori, Masahiro; Ohshima, Tomotaka; Yamamoto, Taiki; Goto, Shunsaku; Nishizawa, Toshihisa; Shimato, Shinji; Izumi, Takashi; Kato, Kyozo

    2016-01-01

    ABSTRACT Our aim was to assess the clinical safety and efficacy of overlap stenting for in-stent restenosis after carotid artery stenting. The study was conducted between July 2008 and February 2015. A database of consecutive carotid artery stenting procedures was retrospectively assessed to identify the cases of in-stent restenosis that were treated with overlap stenting under proximal or distal protection. The clinical and radiological records of the patients were then reviewed. Of the 155 CAS procedures in 149 patients from the database, 6 patients met the inclusion criteria. All the 6 patients were initially treated with moderate dilatation because of the presence of an unstable plaque. The technical success rate of the overlap stenting was 100%, with no 30-day mortality or morbidity. In addition, there was no further in-stent restenosis during a follow-up period of over 12 months. These results indicated that overlap stenting for in-stent restenosis after carotid artery stenting was both safe and effective in our cohort. PMID:27303101

  5. Overlap stenting for in-stent restenosis after carotid artery stenting.

    PubMed

    Nishihori, Masahiro; Ohshima, Tomotaka; Yamamoto, Taiki; Goto, Shunsaku; Nishizawa, Toshihisa; Shimato, Shinji; Izumi, Takashi; Kato, Kyozo

    2016-05-01

    Our aim was to assess the clinical safety and efficacy of overlap stenting for in-stent restenosis after carotid artery stenting. The study was conducted between July 2008 and February 2015. A database of consecutive carotid artery stenting procedures was retrospectively assessed to identify the cases of in-stent restenosis that were treated with overlap stenting under proximal or distal protection. The clinical and radiological records of the patients were then reviewed. Of the 155 CAS procedures in 149 patients from the database, 6 patients met the inclusion criteria. All the 6 patients were initially treated with moderate dilatation because of the presence of an unstable plaque. The technical success rate of the overlap stenting was 100%, with no 30-day mortality or morbidity. In addition, there was no further in-stent restenosis during a follow-up period of over 12 months. These results indicated that overlap stenting for in-stent restenosis after carotid artery stenting was both safe and effective in our cohort. PMID:27303101

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

    PubMed

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

    2012-01-01

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

  7. Evaluation of an asymmetric stent patch design for a patient specific intracranial aneurysm using computational fluid dynamic (CFD) calculations in the computed tomography (CT) derived lumen

    NASA Astrophysics Data System (ADS)

    Kim, Minsuok; Ionita, Ciprian; Tranquebar, Rekha; Hoffmann, Kenneth R.; Taulbee, Dale B.; Meng, Hui; Rudin, Stephen

    2006-03-01

    Stenting may provide a new, less invasive therapeutic option for cerebral aneurysms. However, a conventional porous stent may be insufficient in modifying the blood flow for clinical aneurysms. We designed an asymmetric stent consisting of a low porosity patch welded onto a porous stent for an anterior cerebral artery aneurysm of a specific patient geometry to block the strong inflow jet. To evaluate the effect of the patch on aneurysmal flow dynamics, we "virtually" implanted it into the patient's aneurysm geometry and performed Computational Fluid Dynamics (CFD) analysis. The patch was computationally deformed to fit into the vessel lumen segmented from the patient CT reconstructions. After the flow calculations, a patch with the same design was fabricated using laser cutting techniques and welded onto a commercial porous stent, creating a patient-specific asymmetric stent. This stent was implanted into a phantom, which was imaged with X-ray angiography. The hemodynamics of untreated and stented aneurysms were compared both computationally and experimentally. It was found from CFD of the patient aneurysm that the asymmetric stent effectively blocked the strong inflow jet into the aneurysm and eliminated the flow impingement on the aneurysm wall at the dome. The impact zone with elevated wall shear stress was eliminated, the aneurysmal flow activity was substantially reduced, and the flow was considerably reduced. Experimental observations corresponded well qualitatively with the CFD results. The demonstrated asymmetric stent could lead to a new minimally invasive image guided intervention to reduce aneurysm growth and rupture.

  8. The development of an in vitro test method for predicting the abrasion resistance of textile and metal components of endovascular stent grafts.

    PubMed

    Yao, Tong; Choules, Brian D; Rust, Jon P; King, Martin W

    2014-04-01

    Implantable endovascular stent grafts have become a frequent option for the treatment of abdominal and thoracic aneurysms. Given that such devices are permanent implants, the question of long-term biostability needs to be addressed. This article describes the development of an in vitro stent graft abrasion test method between the graft fabric and metal stent of an endovascular device. Three endpoints were established to determine the abrasion resistance between the fabric and stent surfaces after a predetermined number of abrasion cycles. During initial testing, two types of graft fabric materials, multifilament woven polyester fabric and monofilament woven polyester fabric, and two types of stent materials, laser cut nitinol stents and regular nitinol stent wire, were evaluated under dry and wet conditions. The results have shown that this test method is viable for testing the relative abrasion resistance of the components of endovascular stent grafts. The abrasion resistance of both fabrics was lower in a wet environment compared to being tested dry. Additionally, the multifilament polyester fabric had better abrasion resistance than the monofilament polyester fabric. The laser cut nitinol stent was more aggressive in creating holes and breaking yarns, while the regular nitinol stent wire caused a greater loss in fabric strength.

  9. The development of an in vitro test method for predicting the abrasion resistance of textile and metal components of endovascular stent grafts.

    PubMed

    Yao, Tong; Choules, Brian D; Rust, Jon P; King, Martin W

    2014-04-01

    Implantable endovascular stent grafts have become a frequent option for the treatment of abdominal and thoracic aneurysms. Given that such devices are permanent implants, the question of long-term biostability needs to be addressed. This article describes the development of an in vitro stent graft abrasion test method between the graft fabric and metal stent of an endovascular device. Three endpoints were established to determine the abrasion resistance between the fabric and stent surfaces after a predetermined number of abrasion cycles. During initial testing, two types of graft fabric materials, multifilament woven polyester fabric and monofilament woven polyester fabric, and two types of stent materials, laser cut nitinol stents and regular nitinol stent wire, were evaluated under dry and wet conditions. The results have shown that this test method is viable for testing the relative abrasion resistance of the components of endovascular stent grafts. The abrasion resistance of both fabrics was lower in a wet environment compared to being tested dry. Additionally, the multifilament polyester fabric had better abrasion resistance than the monofilament polyester fabric. The laser cut nitinol stent was more aggressive in creating holes and breaking yarns, while the regular nitinol stent wire caused a greater loss in fabric strength. PMID:24115449

  10. Therapeutic Effect of Akt1 siRNA Nanoparticle Eluting Coronary Stent on Suppression of Post-Angioplasty Restenosis.

    PubMed

    Che, Hui-Lian; Bae, In-Hi; Lim, Kyung Seob; Song, In Taek; Lee, Haeshin; Lee, Duhwan; Kim, Won Jong; Jeong, Myung-Ho; Ahn, Youngkeun

    2016-06-01

    For effective treatment of restenosis, therapeutic genes are delivered locally from a coated stent at the site of injury, leading to inhibition of smooth muscle proliferation and neo-intimal hyperplasia while promoting re-endothelialization. In a previous study, we delivered Akt1 siRNA nanoparticles (ASNs) from a hyaluronic acid (HA)-coated stent surface to specifically suppress the pro-proliferative Akt1 protein in smooth muscle cells (SMCs). In the present study, therapeutic efficacy was investigated in a rabbit restenosis model after percutaneous implantation of an ASN-immobilized stent in a rabbit iliac artery. Quantitative and qualitative analyses of in-stent restenosis were investigated in an in vivo animal model by micro-CT imaging and SEM observation, respectively. Proliferation status and neo-intima formation of the vascular tissues located near ASN-immobilized stents were analyzed by immunohistochemical staining using anti-Akt1 and anti-Ki67 antibodies and histological analyses, such as hematoxylin and eosin staining and Verhoeff's elastic stain. Re-endothelialization after implantation of an ASN-immobilized stent was also analyzed via immunohistochemistry using an anti-CD31 antibody. To elucidate the molecular mechanism related to reducing SMC proliferation and subsequent inhibition of in-stent restenosis in vivo, protein and mRNA expression of Akt1 and downstream signaling proteins were analyzed after isolating SMC-rich samples from the treated vasculature. The implanted Akt1 siRNA-eluting stent efficiently mitigated in-stent restenosis without any side effects and can be considered a successful substitute to current drug-eluting stents. PMID:27319215

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

    PubMed Central

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

    2015-01-01

    Background Glaucoma is a leading cause of irreversible blindness. It is firmly entrenched in the traditional treatment paradigm to start with pharmacotherapy. However, pharmacotherapy is not benign and has been well documented to have a number of significant challenges. Minimally invasive glaucoma surgery (MIGS) that targets the outflow pathway with minimal to no scleral dissection has resulted in the need to reconsider the glaucoma treatment paradigm. Purpose To perform a systematic review and meta-analysis to evaluate and quantify the effect on post-operative intraocular pressure (IOP) and number of topical glaucoma medications, in patients receiving the iStent MIGS device as the solo procedure without concurrent cataract surgery. Methods A systematic review was conducted by searching various databases between January 1, 2000, and June 30, 2014. Studies reporting up to a maximum follow-up period of 24 months were retrieved and screened using the EPPI-Reviewer 4 gateway. Percentage reduction in IOP (IOPR%), and mean reduction in topical glaucoma medications after surgery were computed. Meta-analysis was performed using STATA v. 13.0. The standardized mean difference (SMD) was calculated as the effect size for continuous scale outcomes. Heterogeneity was determined using the I2 statistics, Z-value, and χ2 statistics. Fixed-effect and random-effect models were developed based on heterogeneity. Sub-group analysis was performed based on the number of iStents implanted and the follow-up period. The outcome measures were changes in the IOP and number of glaucoma medications. Results The search strategy identified 105 records from published literature and 9 records from the grey literature. Five studies with 248 subjects were included for quantitative synthesis. A 22% IOP reduction (IOPR%) from baseline occurred at 18-months after one iStent implant, 30% at 6-months after two iStents implantations, and 40% at 6-months after implantation of three iStents. A mean

  12. Stent-Induced Esophageal Perforation: Treatment by Means of Placing a Second Stent After Removal of the Original Stent

    SciTech Connect

    Jung, Gyoo-Sik Park, Sung-Dal; Cho, Young Duk

    2008-05-15

    A case of esophageal perforation caused by a retrievable covered stent is presented. The distal end of the stent was protruding into the mediastinum, which made it impossible to negotiate a guidewire through the stent into the distal esophagus. The stent was successfully removed with use of a stent retrieval set, and esophageal perforation was treated with a second, covered stent with a good result. Fatality associated with this complication might be prevented by virtue of the retrievability of the stent we used. This result points to the effectiveness of a retrievable stent for the palliative treatment of malignant esophageal stricture.

  13. Mechanical Characteristics of Composite Knitted Stents

    SciTech Connect

    Tokuda, Takanori Shomura, Yuzo; Tanigawa, Noboru; Kariya, Shuji; Komemushi, Atsushi; Kojima, Hiroyuki; Sawada, Satoshi

    2009-09-15

    We used metal wires and fibers to fabricate a composite knitted stent and then compare the mechanical characteristics of this stent with those of a pure metallic stent of the same construction in order to develop a stent that offers a comparable degree of expandability as metallic stents but can be used for highly curved lesions that cannot be treated using metallic stents. We fabricated two types of composite knitted stent (N-Z stents), using nitinol wire with a diameter of 0.12 mm and polypara-phenylene-benzobisoxazole (PBO) multifilament fiber (Zyron AS; Toyobo, Osaka, Japan). Stents were knitted into a cylindrical shape using the same textile pattern as a Strecker stent. Two loop lengths (L) of nitinol wire were used in the N-Z stents: L = 1.84 mm (N-Z stent L = 1.84) and L = 2.08 mm (N-Z stent L = 2.08). For the sake of comparison, we fabricated a metallic stent of nitinol using the same textile pattern (N-N stent L = 1.92). We applied a radial compression force diametrically to each stent and applied a bending force diametrically at the free end of a stent with one end fixed in order to evaluate the relationship between stent elasticity and load values. In addition, we macroscopically evaluated the generation of kinks when the stent was bent 180{sup o}. The radial compressive force when the stent diameter was reduced by 53% was 6.44 N in the case of N-Z stent L = 1.84, 6.14 N in the case of N-Z stent L = 2.08, and 4.96 N in the case of N-N stent L = 1.92 mm. The composite stent had a radial compressive force higher than that of a metallic stent. The restoring force to longitudinal direction at a 90{sup o} bending angle was 0.005 N for N-Z stent L = 1.84, 0.003 N for N-Z stent L = 2.08, and 0.034 N for N-N stent L = 1.92. The restoring force of the composite stent was significantly lower. Finally, the composite stent generated no definitive kinks at a bending angle of 180{sup o}, regardless of loop length. However, the N-N stent clearly produced kinks, causing

  14. Prevention of Intracranial In-stent Restenoses: Predilatation with a Drug Eluting Balloon, Followed by the Deployment of a Self-Expanding Stent

    SciTech Connect

    Vajda, Zsolt Guethe, Thomas Perez, Marta Aguilar Kurre, Wiebke; Schmid, Elisabeth Baezner, Hansjoerg; Henkes, Hans

    2013-04-15

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

  15. [Radioactivity of phosphorus implanted TiNi alloy].

    PubMed

    Zhao, Xingke; Cai, Wei; Zhao, Liancheng

    2003-09-01

    Exposed to neutron flow, the phosphorus implanted TiNi alloy gets radioactive. This radioactive material is used in vascular stent for prevention and cure of restenosis. Phosphorus implantation is carried out in a plasma immerged ion implantation system, and the dose of phosphorus implantation is in the range of 2-10 x 10(17) cm-2. After ion implantation, the alloy is exposed to the slow neutron flow in a nuclear reactor, the dose of the slow neutron is 1.39-5.88 x 10(19) n/cm2. The radioactivity of the TiNi alloy was measured by liquid scintillation spectrometry and radio-chromic-film dosimetry. The result shows that whether the phosphorus is implanted or not, the TiNi alloy comes to be radioactive after exposure to neutron flow. Just after neutron irradiation, the radiation dose of phosphorus implanted TiNi alloy is about one hundred times higher than that of un-phosphorus implanted TiNi alloy. The radiation difference between phosphorus and un-phosphorus implanted alloy decreases as time elapses. Within three months after neutron irradiation, the average half-decay period of phosphorus implanted TiNi alloy is about 62 days. The radiation ray penetration of phosphorus implanted TiNi alloy is deeper than that of pure 32P; this is of benefit to making radiation uniformity between stent struts and reducing radiation grads beyond the edge of stent.

  16. Mometasone implant for chronic rhinosinusitis.

    PubMed

    Wei, Calvin C; Kennedy, David W

    2012-01-01

    The Propel mometasone-eluting stent (Intersect ENT, Palo Alto, CA) is the first Food and Drug Administration-approved device for delivering steroid medication into the ethmoid cavity following surgery. The implant is composed of a biodegradable polymer in a lattice pattern that expands in a spring-like fashion to conform to the walls of a dissected ethmoid cavity and contains a total of 370 μg of mometasone furoate designed for gradual release over 30 days. The purpose of this article is to review the mode of action and the evidence supporting the efficacy of this novel technology. Three recently published clinical trials have demonstrated that the mometasone-eluting stent produced statistically significant reductions in inflammation, polyp formation, and postoperative adhesions. In addition, the implant has been found to significantly reduce the need for postoperative administration of oral steroids and to decrease the frequency of postoperative lysis of adhesions. Minimal adverse effects were reported in these trials and included infection, crusting, and granulation tissue formation. Although the placement of steroid-impregnated packing, stents, sponges, and gels has previously been used in the postoperative sinus cavities, the Propel mometasone-eluting stent introduces a new mechanism for localized and controlled delivery of topical therapy directly to the nasal mucosa for chronic rhinosinusitis.

  17. [Stent Grafting for Aortic Dissection].

    PubMed

    Uchida, Naomichi

    2016-07-01

    The purpose of stent graft for aortic dissection is to terminate antegrade blood flow into the false lumen through primary entry. Early intervention for primary entry makes excellent aortic remodeling and emergent stent grafting for complicated acute type B aortic dissection is supported as a class I. On the other hand stent grafting for chronic aortic dissection is controversial. Early stent grafting is considered with in 6 months after on-set if the diameter of the descending aorta is more than 40 mm. Additional interventions for residual false lumen on the downstream aorta are still required. Stent graft for re-entry, candy-plug technique, and double stenting, other effective re-interventions were reported. Best treatment on the basis of each anatomical and physical characteristics should be selected in each institution. Frozen elephant trunk is alternative procedure for aortic dissection without the need to take account of proximal anatomical limitation and effective for acute type A aortic dissection. PMID:27440026

  18. Mechanical thrombectomy using Rotarex system and stent-in-stent placement for treatment of distal femoral artery occlusion secondary to stent fracture – a case report and literature review

    PubMed Central

    Dys, Krzysztof; Drelichowska-Durawa, Justyna; Dołega-Kozierowski, Bartosz; Lis, Michał; Sokratous, Kyriakos; Iwanowski, Wojciech; Drelichowski, Stanisław; Witkiewicz, Wojciech

    2013-01-01

    Summary Background: Treatment of peripheral arterial diseases may be distinguished into conservative and interventional management; the latter is divided into surgical and endovascular procedures. Management of peripheral artery stenosis and occlusion with vascular stents is associated with the risk of late complications such as restenosis, stent fracture or dislocation. Case Report: A 62-year-old woman with generalized atherosclerosis, particularly extensive in lower limb arteries, was admitted to the Department of Angiology 11 months after having an endovascular procedure performed due to critical ischemia of left lower limb. Because of stent occlusion, a decision to perform angiographic examination of lower limb arteries was made. Examination revealed occlusion of the superficial femoral artery along its entire length, including previously implanted stents. Distal stent was fractured with slight dislocation of the proximal segment. A decision was made to perform mechanical thrombectomy using a Rotarex system followed by a stent-in-stent placement procedure. Follow-up angiography and ultrasound scan performed 24 hours after the procedure revealed a patent vessel with satisfactory blood flow. Discussion: Nowadays, imaging diagnostics of peripheral artery stenosis involves non-invasive examinations such as ultrasound, minimally invasive examinations such as angio-MRI and MDCT, or invasive examinations such as DSA and IVUS. DSA examinations are used to confirm significant stenosis or occlusion of a vessel, particularly when qualifying a patient for endovascular treatment. Due to their anatomic location, the superficial femoral artery and the popliteal artery are subject to various forces e.g. those exerted by the working muscles. Mechanical thrombectomy and atherectomy are efficient methods of arterial recanalization used in the treatment of acute, subacute or even chronic occlusions or stenosis of peripheral vessels. Conclusions: Frequency of angioplasty and

  19. 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.

  20. Accidental Stenting Out of Stent: A Lesson from No-Reflow after New Stent Deployment Outside the Prior Stent

    PubMed Central

    Lai, Chih-Hung; Sung, Shih-Hsien; Lee, Wen-Lieng; Juan, Yu-Hsiang; Chang, Szu-Ling; Lu, Tse-Min

    2016-01-01

    An operator can be unaware that the guide wire has accidentally advanced into space outside the previous stent, which can result in deformation of the previous stent when a new stent is deployed outside the prior stent. We herein have reported a case of accidental guide wire advancement into a previously dissected lumen of right coronary artery (RCA), resulting in a new stent deploying outside the prior stent, resulting in deformity of the prior stent. Thrombus and friable atheromatous plaques dislodged and migrated to occlude distal RCA when attempting to restore the proximal luminal diameter by balloon inflation, resulting in profound shock with asystole. IVUS was successful in identifying the cause, and the thrombus was removed successfully by manual aspiration. Due to the poor endothelization of a recent stenting, clinicians should be particularly careful of possible wire advancing outside the stent structure, which can result in prominent thrombus or atheromatous debris occluding the distal vessel, and IVUS may be useful in confirming the cause of no-reflow. PMID:27274180

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

    PubMed Central

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

    2015-01-01

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

  2. Treatment of Superior Vena Cava (SVC) Syndrome and Inferior Vena Cava (IVC) Thrombosis in a Patient with Colorectal Cancer: Combination of SVC Stenting and IVC Filter Placement to Palliate Symptoms and Pave the Way for Port Implantation

    SciTech Connect

    Sauter, Alexander; Triller, Juergen; Schmidt, Felix; Kickuth, Ralph

    2008-07-15

    Thrombosis of the inferior vena cava is a life-threatening complication in cancer patients leading to pulmonary embolism. These patients can also be affected by superior vena cava syndrome causing dyspnea followed by trunk or extremity swelling. We report the case of a 61-year-old female suffering from an extended colorectal tumor who became affected by both of the mentioned complications. Due to thrombus formation within the right vena jugularis interna, thrombosis of the inferior vena cava, and superior vena cava syndrome, a combined interventional procedure via a left jugular access with stenting of the superior vena cava and filter placement into the inferior vena cava was performed As a consequence, relief of the patient's symptoms, prevention of pulmonary embolism, and paving of the way for further venous chemotherapy were achieved.

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

    PubMed Central

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

    2015-01-01

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

  4. Percutaneous Interventions in Radiation-Associated Coronary In-Stent Restenosis

    SciTech Connect

    Wexberg, P. Beran, G.; Lang, I.; Siostrzonek, P.; Kirisits, C.; Glogar, D.; Gottsauner-Wolf, M.

    2003-04-15

    This study was performed to evaluate the outcome of percutaneous revascularization in 'edge restenoses' developing after radioactive stent implantation in de novo and in-stentlesions. Twenty-one consecutive patients undergoing target lesion revascularization (TLR) at any follow-up after phosphorus-32 radioacttive stent implantation were included in this study. We assessed the incidence of death, myocardial infarction, repeated TLR and recurrent angina over the following 18 months. After 6 months, TLR rate was 28.6%, and no stent thromboses, deaths or Q-wave myocardial infarctions occurred. Among the patients with TLR there were significantly more subjects who had received a radioactive stent in a previous in-stent restenosis (66.7% vs. 0% in patients without second restenosis; P < 0.001), or who had received two radioactive stents (83.3% vs. 33.3%; P = 0.038).After 18 months, TLR rate was 33.3%, and two patients (9.5%) had died. Restenosis after intravascular radiotherapy can be safely treated by percutaneous interventional techniques, yielding an acceptable clinical result within 18 months.

  5. Nasal packing and stenting

    PubMed Central

    Weber, Rainer K.

    2011-01-01

    Nasal packs are indispensable in ENT practice. This study reviews current indications, effectiveness and risks of nasal packs and stents. In endoscopic surgery, nasal packs should always have smooth surfaces to minimize mucosal damage, improve wound healing and increase patient comfort. Functional endoscopic endonasal sinus surgery allows the use of modern nasal packs, since pressure is no longer required. So called hemostatic/resorbable materials are a first step in this direction. However, they may lead to adhesions and foreign body reactions in mucosal membranes. Simple occlusion is an effective method for creating a moist milieu for improved wound healing and avoiding dryness. Stenting of the frontal sinus is recommended if surgery fails to produce a wide, physiologically shaped drainage path that is sufficiently covered by intact tissue. PMID:22073095

  6. Direct microscopic observation of striations in a fractured section of a sirolimus-eluting stent (Cypher Bx Velocity®) indicates induction of stent fracture by continuous shear stress.

    PubMed

    Endo, Akira; Ishikawa, Tetsuya; Suzuki, Teruhiko; Kashiwagi, Yusuke; Mutoh, Makoto

    2011-01-01

    A 73-year-old woman with severe congestive heart failure was treated by implantation with a sirolimus-eluting stent (SES; Cypher Bx Velocity(®)) in the left main coronary artery (LMCA) using the staged T-stent, kissing balloon, and hugging balloon techniques. Follow-up coronary multislice computed tomography after 10 months revealed that SES was completely fractured in 2 directions; the fractured stent appeared in the shape of the letter "L" and had migrated into the aorta. An SES fragment was surgically removed and subsequent electron microscopy revealed striations (striped patterns in fractured sections) on the fracture plane, indicating continuous shear stress after SES implantation in the LMCA. This case provides direct evidence of continuous shear stress on the SES and indicates the necessity of improving the structure of the stent such that it can withstand shear stress. PMID:21828954

  7. Reconstruction of Saccular and Dissected Intracranial Aneurysms Using Solitaire™ AB Stents

    PubMed Central

    Xu, Yi; Hong, Bo; Huang, Qing-Hai; Zhao, Wen-Yuan; Yang, Peng-Fei; Liu, Jian-Min

    2013-01-01

    Introduction We aimed to evaluate the feasibility, safety, efficacy, and predictors for outcome of reconstructive treatment with Solitaire™ AB stent(s) based on 54 cases of saccular aneurysms and 14 of acute symptomatic dissecting aneurysms. Methods Fifty-eight consecutive patients (M/F = 28/30; median age, 53 years) harbouring 68 aneurysms (ruptured/unruptured = 12/56) underwent treatment with Solitaire™ AB stent(s) implantation between April 2010 and August 2011 in our institution. The data were retrospectively reviewed and analysed. Results The technical success rate of Solitaire™ AB stenting was 100%. The rates of the overall and the treatment-related adverse events were 9% (6/68) and 6% (4/68), respectively, and the recurrent rate was 1% (1/68). All of the adverse events (n = 6) occurred in tiny (n = 1, ≤3 mm) or small (n = 5, >3 to ≤10 mm) aneurysms. The majority (75%, 3/4) of thromboembolic events (thrombus, n = 2; infarction, n = 2) occurred in ruptured lesions, and 2 intraprocedural aneurysm ruptures occurred in the course of coiling when the stent(s) was/were applied within 6 months. Subarachnoid haemorrhages (SAH, p<0.05) and immediate occlusion grades (p<0.05) were predictors for overall adverse events by univariate analysis. Compared with the immediate post-treatment angiographic results, the follow-up angiographic imaging (mean, 13 months; range, 6–25 months) revealed that stent(s) implantation enhanced the rate of class I occlusion from 34% (23/68) to 93% (63/68). SAH was the only predictor for unfavourable outcomes (the modified Rankin Scale score [mRS], 2–6) during the mean 19-month (range, 12–27 months) of clinical follow-ups (p<0.05). Conclusions Although the complete obliteration of tiny and small aneurysms without complications remains a challenge, stent(s) implantation could lead to further occlusion of incompletely coiled aneurysms. SAH and the occlusion grade were the primary predictors for adverse

  8. Carotid stenting and endarterectomy.

    PubMed

    Yip, Hon-Kan; Sung, Pei-Hsun; Wu, Chiung-Jen; Yu, Cheuk-Man

    2016-07-01

    Stroke, either ischemic or hemorrhagic, remains the second commonest cause of death worldwide in the last decade. Etiologies for ischemic stroke (IS) vary widely. Atherothrombotic occlusion is an essential cause to which carotid artery stenosis (CAS) is a major contributor. Administration of anti-platelet agent to patients with CAS has been shown to reduce incidence of long-term IS. In additional, in patients with symptomatic CAS, clinical trials have demonstrated that carotid endarterectomy (CEA) is superior to medical therapy for prevention of future CAS-related IS. However, CEA is not suitable for CAS post-radiotherapy or those located at higher level of the internal carotid artery; and major complications of this procedure including cranial nerve injuries have stimulated the interest of using percutaneous transfemoral carotid stenting as an alternative approach. Although transfemoral arterial approach of carotid stenting is not inferior to CEA in improving clinical outcomes, it has been reported to be associated with vascular complication and has its limitations in patients with athero-occlusive disease of abdominal aorta or bilateral iliac arteries, level II or III aortic arch, or bovine type carotid arterial anatomy. Therefore, transradial/transbrachial arterial approach has emerged as a novel method for carotid stenting. This article provides a critical review on interventional approaches for the treatment of CAS.

  9. Hemodynamics in Idealized Stented Coronary Arteries: Important Stent Design Considerations.

    PubMed

    Beier, Susann; Ormiston, John; Webster, Mark; Cater, John; Norris, Stuart; Medrano-Gracia, Pau; Young, Alistair; Cowan, Brett

    2016-02-01

    Stent induced hemodynamic changes in the coronary arteries are associated with higher risk of adverse clinical outcome. The purpose of this study was to evaluate the impact of stent design on wall shear stress (WSS), time average WSS, and WSS gradient (WSSG), in idealized stent geometries using computational fluid dynamics. Strut spacing, thickness, luminal protrusion, and malapposition were systematically investigated and a comparison made between two commercially available stents (Omega and Biomatrix). Narrower strut spacing led to larger areas of adverse low WSS and high WSSG but these effects were mitigated when strut size was reduced, particularly for WSSG. Local hemodynamics worsened with luminal protrusion of the stent and with stent malapposition, adverse high WSS and WSSG were identified around peak flow and throughout the cardiac cycle respectively. For the Biomatrix stent, the adverse effect of thicker struts was mitigated by greater strut spacing, radial cell offset and flow-aligned struts. In conclusion, adverse hemodynamic effects of specific design features (such as strut size and narrow spacing) can be mitigated when combined with other hemodynamically beneficial design features but increased luminal protrusion can worsen the stent's hemodynamic profile significantly.

  10. Spiral CT During Selective Accessory Renal Artery Angiography: Assessment of Vascular Territory Before Aortic Stent-Grafting

    SciTech Connect

    Dorffner, Roland; Thurnher, Siegfried; Prokesch, Rupert; Youssefzadeh, Soraya; Hoelzenbein, Thomas; Lammer, Johannes

    1998-03-15

    We evaluated the vascular territory of accessory renal arteries in cases where the vessel might be overlapped by an aortic stent-graft. Spiral CT during selective accessory renal artery angiography was performed in four patients with abdominal aortic aneurysms (including one with a horseshoe kidney). The volume of the vascular territory of each renal artery was measured using a software program provided by the CT unit manufacturer. The supernumerary renal arteries perfused 32%, 37%, 15%, and 16% of the total renal mass, respectively. In two patients, stent-grafts were implanted, which resulted in occlusion of the supernumerary renal artery. The volume of the renal infarction was equal to the volume perfused by the artery as calculated before implantation of the stent-graft.The method proposed is accurate for estimating the size of the expected renal infarction. It might help to determine whether placement of a stent-graft is acceptable.

  11. Evolution of covered stents in the contemporary era: clinical application, materials and manufacturing strategies using nanotechnology.

    PubMed

    Farhatnia, Yasmin; Tan, Aaron; Motiwala, Aamir; Cousins, Brian G; Seifalian, Alexander M

    2013-01-01

    Endovascular stents have revolutionised the field of interventional cardiology. Despite their excellent clinical outcome complications associated with percutaneous stent implantation following the procedure have remained a major drawback in their widespread use. To overcome such limitations, a number of novel endovascular stents have emerged including a covered stent wrapped in a thin membrane sleeve. As well as prevention of complications associated with stenting, covered stents owing to their physical barrier are used as the treatment option of choice for trauma devices during emergency situations and to treat a number of pathological disease states. The aim of this review is to provide the reader with an overall objective outlook in the use of covered stents as a treatment option in a number of vascular complications and addresses their design and materials used in the manufacturing process. In addition, new strategies are highlighted and future prospects with the emergence of novel smart alloys for 3D scaffolds and the use of nanotechnology in the development of nanocomposite materials. PMID:23305892

  12. In Vivo Study of Polyurethane-Coated Gianturco-Rosch Biliary Z-Stents

    SciTech Connect

    Severini, Aldo; Mantero, Sara; Tanzi, Maria Cristina; Cigada, Alberto; Addis, Flaminio; Cozzi, Guido; Salvetti, Monica; Andreola, Salvatore; Motta, Antonella; Regalia, Enrico; Pulvirenti, Andrea; De Pedri, Enrico; Doci, Roberto

    1999-11-15

    Purpose: Prototypes of Gianturco-Rosch Z-stents coated with polycarbonate urethane (PCU) were placed in the biliary tree of pigs, in order to test their biomechanical behavior, stability, and biocompatibility. Methods: The stents were surgically implanted in the common bile duct of three pairs of pigs, which were killed after 1, 3, and 6 months respectively. Explanted livers from pigs of the same race, age, and size were used to provide comparative data. The bile ducts were radiologically and histopathologically examined; the stents were processed and examined by scanning electron microscopy. Results: No complications occurred and the animals showed a normal weight gain. The main bile duct appeared radiologically and macroscopically dilated, but the stents proved to be in place. Histologically, the bile duct epithelium was destroyed, but neither hyperplastic nor inflammatory fibrotic reactions of the wall were evident. Both the metallic structure and the polymeric coating of the stents were intact. A layer of organic material with a maximum thickness of approximately 3 {mu}m was evident on the inner surface of the stents. Conclusion: The present in vivo study demonstrates the biocompatibility, efficacy, and stability of PCU-coated Gianturco-Rosch stents in the biliary environment.

  13. Late Complication after Superficial Femoral Artery (SFA) Aneurysm: Stent-graft Expulsion Outside the Skin

    SciTech Connect

    Pecoraro, Felice Sabatino, Ermanno R.; Dinoto, Ettore; Rosa, Giuliana La; Corte, Giuseppe; Bajardi, Guido

    2015-10-15

    A 78-year-old man presented with a 7-cm aneurysm in the left superficial femoral artery, which was considered unfit and anatomically unsuitable for conventional open surgery for multiple comorbidities. The patient was treated with stent-graft [Viabhan stent-graft (WL Gore and Associates, Flagstaff, AZ)]. Two years from stent-graft implantation, the patient presented a purulent secretion and a spontaneous external expulsion through a fistulous channel. No claudication symptoms or hemorrhagic signs were present. The pus and device cultures were positive for Staphylococcus aureus sensitive to piperacillin/tazobactam. Patient management consisted of fistula drainage, systemic antibiotic therapy, and daily wound dressing. At 1-month follow-up, the wound was closed. To our knowledge, this is the first case of this type of stent-graft complication presenting with external expulsion.

  14. Fabrication of hydrophobic structures on coronary stent surface based on direct three-beam laser interference lithography

    NASA Astrophysics Data System (ADS)

    Gao, Long-yue; Zhou, Wei-qi; Wang, Yuan-bo; Wang, Si-qi; Bai, Chong; Li, Shi-ming; Liu, Bin; Wang, Jun-nan; Cui, Cheng-kun; Li, Yong-liang

    2016-05-01

    To solve the problems with coronary stent implantation, coronary artery stent surface was directly modified by three-beam laser interference lithography through imitating the water-repellent surface of lotus leaf, and uniform micro-nano structures with the controllable period were fabricated. The morphological properties and contact angle (CA) of the microstructure were measured by scanning electron microscope (SEM) and CA system. The water repellency of stent was also evaluated by the contact and then separation between the water drop and the stent. The results show that the close-packed concave structure with the period of about 12 μm can be fabricated on the stent surface with special parameters (incident angle of 3°, laser energy density of 2.2 J·cm-2 and exposure time of 80 s) by using the three-beam laser at 1 064 nm, and the structure has good water repellency with CA of 120°.

  15. Coronary stenting in 1000 consecutive patients. Long-term clinical and angiographic results.

    PubMed

    Colombo, A; Di Mario, C; Reimers, B; Blengino, S; Akiyama, T; Ferraro, M; Martini, G; Di Francesco, L; Finci, L

    1997-01-01

    Coronary stent implantation has become an accepted treatment for selected patients but the long-term outcome after stent implantation has not been investigated in a large unselected population. This study reports clinical and angiographic results after coronary stent implantation in a consecutive group of 1000 patients treated between November 1989 and June 1994. A total of 2012 stents were implanted in 1216 lesions. The anticoagulation regimen after successful stenting was abolished in the last 499 patients, treated with aspirin and ticlopidina. Complex lesions (type B2, type C lesions and chronic total occlusions) were less frequent in the group with anticoagulation (67%, 355/529 lesions) than in the group without anticoagulation (76%, 485/641; p < 0.01). Vessel size was also significantly smaller in the group with no anticoagulation (3.21 +/- 0.50 mm vs 2.89 +/- 0.70 mm; p < 0.001). Procedural success was achieved in 96% of cases. Major complications occurred in 49 pts, including death (1%), emergency bypass surgery (2.7%), and myocardial infarction (2.1%). Subacute stent thrombosis, observed in 2.6% of the patients treated with anticoagulation, decreased to 1% in the last 499 patients receiving only antiplatelet drugs after high pressure stent expansion controlled with intravascular ultrasound (p < 0.05). Angiographic follow-up was obtained at a mean interval of 6.6 +/- 3.0 months in 718 patients (75% of the eligible candidates). The global restenosis rate (greater than 50% diameter stenosis) was 22%, with no statistically significant difference in patients with and without anticoagulation after stenting. Clinical follow-up was available in 890 patients at a mean interval of 14 +/- 17 months. Late cardiac events occurred in 251 patients and included: 159 repeat coronary angioplasties for restenosis (20%), 114 coronary angioplasties for de novo lesions (10%), 33 elective by-pass surgery operations (3.7%) and 42 late deaths (4.7%). At the most recent follow

  16. A Universal Delivery System for Percutaneous Heart Valve Implantation.

    PubMed

    Bartosch, Marco; Peters, Heiner; Spriestersbach, Hendrik; O H-Ici, Darach; Berger, Felix; Schmitt, Boris

    2016-09-01

    Transcatheter heart valve implantation is an emerging technology and an alternative to surgical valve replacement. Most existing systems consist of valves sewn into balloon-expandable stents with a delivery catheter functioning with the specific valve only. The aim of this study was to develop a universally applicable delivery system (DS) for plane stents, valves sewn into both balloon-expandable and self-expandable stents and feasible for use with different access routes. A DS was designed and manufactured in five different diameters. The requirements were derived from the implants, the implantation technique and the cardiovascular geometry of the experimental sheep. The combination of a self-expandable Nitinol stent and a jugular access point represented the major challenge as both flexibility and rigidity of the DS were required. To fulfill these contradicting mechanical properties the sheaths were comprised of a soft outer polymer tube with a stainless steel coiled spring inside. Tissue-engineered and pericardial pulmonary valves were implanted. Also polymeric and balloon-expandable stents were delivered to various positions in the vascular system. The initial success rate was 70.5%. After refinement of the DS, a success rate of 83.3% was achieved with the remaining failed implantations resulting from inadequate sizes of the prostheses. PMID:26864537

  17. A new removable airway stent

    PubMed Central

    Amundsen, Tore; Sørhaug, Sveinung; Leira, Håkon Olav; Tyvold, Stig Sverre; Langø, Thomas; Hammer, Tommy; Manstad-Hulaas, Frode; Mattsson, Erney

    2016-01-01

    Background Malignant airway obstruction is a feared complication and will most probably occur more frequently in the future because of increasing cancer incidence and increased life expectancy in cancer patients. Minimal invasive treatment using airway stents represents a meaningful and life-saving palliation. We present a new removable airway stent for improved individualised treatment. Methods To our knowledge, the new airway stent is the world's first knitted and uncovered self-expanding metal stent, which can unravel and be completely removed. In an in vivo model using two anaesthetised and spontaneously breathing pigs, we deployed and subsequently removed the stents by unravelling the device. The procedures were executed by flexible bronchoscopy in an acute and a chronic setting – a ‘proof-of-principle’ study. Results The new stent was easily and accurately deployed in the central airways, and it remained fixed in its original position. It was easy to unravel and completely remove from the airways without clinically significant complications. During the presence of the stent in the chronic study, granulation tissue was induced. This tissue disappeared spontaneously with the removal. Conclusions The new removable stent functioned according to its purpose and unravelled easily, and it was completely removed without significant technical or medical complications. Induced granulation tissue disappeared spontaneously. Further studies on animals and humans are needed to define its optimal indications and future use. PMID:27608269

  18. Nephroureteral Stents: Principles and Techniques

    PubMed Central

    Makramalla, Abouelmagd; Zuckerman, Darryl A.

    2011-01-01

    Nephroureteral stents including antegrade, retrograde, or internal (double-J) stents are routinely placed by interventional radiologists. The purpose of this review is to provide a detailed and comprehensive description of indications, contraindications, technique, and various technical challenges of these procedures. Also pre- and postprocedure management of patients will be discussed including routine follow-up and dealing with potential complications. PMID:23204635

  19. [Malignant esophageal-respiratory fistula and esophageal stenosis treated with a Gianturco-Z-stent].

    PubMed

    Solt, J; Boros, S; Zoltán, I; Horváth, O P; Andics, L; Bajor, J

    1998-10-11

    Oesophago-respiratory fistula in most instances in a complication of advanced malignant tumours of the oesophagus or the lung. In our patient group eleven oesophago-respiratory and one gastro-respiratory fistulas were encountered. Three patients were operated upon. In one of them with achalasia, early oesophageal carcinoma was discovered in the background of the fistula. Two patients had fistulas without of oesophageal narrowing, therefore, stent implantation into the trachea and bronchus was performed. One of them was previously managed endoscopically with lyodura plug and fibrin glue, but only temporary occlusion of the fistula was obtained. In five patients, seven conventional oesophageal prosthesis (6 Cook, 1 Rüsch) were used to close the fistulas. In one of these patients, three oesophago-respiratory fistulas developed one after the other at the level of the prosthesis funnel. They were closed with three prostheses connected with short silicone tubes. In the last two patients, Gianturco-Z stent was employed. Its advantages over the plastic prostheses include small basic and lager final luminal diameter, lesser predilatation, easier implantation, lower complication and mortality rate. The silicone coated and double funnel stent with expansile force is effective in fistulas closure. On implantation, stent shortening in minimal, allowing precise placement of the stent even in proximal malignant oesophageal stenosis with oesophago-bronchial fistula. The high price of the stent is compensated for by the lower complication rate, shorter hospitalization and subsequent reduction is hospital expenses. Therefore these metal stents should be financed by the National Health Service, at least in specialized centers for managing patients with dysphagia. PMID:9805459

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

    PubMed

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

    1998-11-01

    The safety, efficacy, angiographic and histological effects of a new 316 L, SS seamless stainless steel tubular stent (V-Flexª, Global Therapeutics, Broomfield, Colorado) was evaluated in a porcine coronary and peripheral artery model. Implantation in the right coronary artery was successful in all 16 pigs. Eight pigs were angiographically controlled after 6 weeks and then sacrificed for morphometric analysis. All stented coronary vessels were widely patent at this moment and morphometric analysis showed only a mild fibromuscular neointimal hyperplasia resulting in a neointimal hyperplasia of 1.15 +/- 0.38 mm2. The remaining 8 pigs were controlled and sacrificed at 12 weeks. At that time, all stented vessels were patent and neointimal hyperplasia was 1.22 +/- 0.34 mm2. Comparison with the Palmaz-Schatzª coronary stent (Cordis, Miami, Florida) in a porcine peripheral artery model demonstrated significantly less neointimal hyperplasia at 6 weeks (1.11 +/- 0.73 vs. 2.40 +/- 0.36, p = 0.001) and at 12 weeks (1.53 +/- 0.42 vs. 2.47 +/- 0.63, p = 0.003) for the V-Flex stent. In conclusion, V-Flex coronary stent implantation in a porcine coronary and peripheral arteries results in a high procedural success rate without subacute thrombotic occlusions, despite no further anticoagulation nor antiplatelet therapy. Six and 12 week histopathological and morphometric evaluation demonstrated only a mild fibromuscular neointimal hyperplasia. Comparison with the Palmaz-Schatz coronary stent in a peripheral artery model showed significantly less neointimal hyperplasia in the V-Flex stent. PMID:10762839

  1. Novel Fabrication of MicroRNA Nanoparticle-Coated Coronary Stent for Prevention of Post-Angioplasty Restenosis

    PubMed Central

    Che, Hui-Lian; Bae, In-Ho; Lim, Kyung Seob; Uthaman, Saji; Song, In Taek; Lee, Haeshin; Lee, Duhwan; Kim, Won Jong; Ahn, Youngkeun; Jeong, Myung-Ho

    2016-01-01

    Background and Objectives MicroRNA 145 is known to be responsible for cellular proliferation, and its enhanced expression reportedly inhibits the retardation of vascular smooth muscle cell growth specifically. In this study, we developed a microRNA 145 nanoparticle immobilized, hyaluronic acid (HA)-coated stent. Materials and Methods For the gene therapy, we used disulfide cross-linked low molecular polyethylenimine as the carrier. The microRNA 145 was labeled with YOYO-1 and the fluorescent microscopy images were obtained. The release of microRNA 145 from the stent was measured with an ultra violet spectrophotometer. The downstream targeting of the c-Myc protein and green fluorescent protein was determined by Western blotting. Finally, we deployed microRNA 145/ssPEI nanoparticles immobilized on HA-coated stents in the balloon-injured external iliac artery in a rabbit restenosis model. Results Cellular viability of the nanoparticle-immobilized surface tested using A10 vascular smooth muscle cells showed that MSN exhibited negligible cytotoxicity. In addition, microRNA 145 and downstream signaling proteins were identified by western blots with smooth muscle cell (SMC) lysates from the transfected A10 cell, as the molecular mechanism for decreased SMC proliferation that results in the inhibition of in-stent restenosis. MicroRNA 145 released from the stent suppressed the growth of the smooth muscle at the peri-stent implantation area, resulting in the prevention of restenosis at the post-implantation. We investigated the qualitative analyses of in-stent restenosis in the rabbit model using micro-computed tomography imaging and histological staining. Conclusion MicroRNA 145-eluting stent mitigated in-stent restenosis efficiently with no side effects and can be considered a successful substitute to the current drug-eluting stent. PMID:26798382

  2. Are Aortic Stent Grafts Safe in Pregnancy?

    PubMed Central

    Khandanpour, Nader; Mehta, Tapan A.; Adiseshiah, M.; Meyer, Felicity J.

    2015-01-01

    Aortic stent grafts are increasingly used to treat aortic aneurysms and also other aortic pathologies. The safety of aortic stent grafts in pregnancy has never been studied or reported. We report on two cases of aortic stent grafts in pregnant women and discuss the effect of pregnancy on these aortic stent grafts. PMID:26229702

  3. Prosthodontic management of sulcoplasty and sialodochoplasty with a conforming surgical stent.

    PubMed

    Berg, Robert W; Goldman, Barry M; Kurtz, Kenneth; Schweitzer, Kenneth; Kraut, Richard A

    2008-01-01

    This clinical report describes the management of chronic, proliferative inflammatory epithelial and fibrous hyperplasia following loss of a mandibular implant-retained prosthesis. A classic surgical technique was used. The patient was referred to the oral surgeon for sialodochoplasty and sulcoplasty. With a combination of surgery and prosthodontic management with a conforming surgical stent, a satisfactory denture foundation was created, allowing for fabrication of an implant-retained definitive prosthesis.

  4. Coronary stent technology: a narrative review.

    PubMed

    Chen, Daniel; Jepson, Nigel

    2016-09-19

    Coronary angioplasty and coronary artery stents have revolutionised interventional cardiology. Contemporary coronary stent technology continues to seek to improve on the outcomes of the preceding generation of devices by refining their design, structure and component materials. These technologies include new generations of drug-eluting stents, non-polymeric stents, bioresorbable polymer-coated stents, and fully bioresorbable scaffolds. This review discusses the evolution of coronary stent technology, the efficacy and safety of currently available devices, and the rationale for new generation platforms as efforts continue to design the ideal coronary stent technology. PMID:27627940

  5. Non-viral eNOS gene delivery and transfection with stents for the treatment of restenosis

    PubMed Central

    2010-01-01

    Background In this study, we have examined local non-viral gene delivery, transfection, and therapeutic efficacy of endothelial nitric oxide synthase (eNOS) encoding plasmid DNA administered using coated stents in a rabbit iliac artery restenosis model. Methods Lipopolyplexes (LPPs) with eNOS expressing plasmid DNA were immobilized on stainless steel stents using poly(D,L-lactide-co-glycolide) (PLGA) and type B gelatin coatings. The gene-eluting stents were implanted bilaterally in the denuded iliac arteries and eNOS transfection and therapeutic efficacy were examined 14 days after implantation. Results The results show that non-viral lipopolyplex-coated stents can efficiently tranfect eNOS locally in the arterial lumen assessed by PCR and ELISA. Human eNOS ELISA levels were significantly raised 24 hours after transfection compared to controls (125 pg eNOS compared to <50 pg for all controls including naked DNA). Local eNOS production suppressed smooth muscle cell proliferation and promoted re-endothelialization of the artery showing a significant reduction in restenosis of 1.75 neointima/media ratio for stents with lipoplexes encoding eNOS compared with 2.3 neointima/media ratio for stents with lipoplexes encosing an empty vector. Conclusions These results support the hypothesis that a potent non-viral gene vector encoding for eNOS coated onto a stent can inhibit restenosis through inhibition of smooth muscle cell growth and promotion of a healthy endothelium. PMID:20875110

  6. Ureteral stents: new ideas, new designs

    PubMed Central

    Al-Aown, Abdulrahman; Kyriazis, Iason; Kallidonis, Panagiotis; Kraniotis, Pantelis; Rigopoulos, Christos; Karnabatidis, Dimitrios; Petsas, Theodore; Liatsikos, Evangelos

    2010-01-01

    Ureteral stents represent a minimally invasive alternative to preserve urinary drainage whenever ureteral patency is deteriorated or is under a significant risk to be occluded due to extrinsic or intrinsic etiologies. The ideal stent that would combine perfect long-term efficacy with no stent-related morbidity is still lacking and stent usage is associated with several adverse effects that limit its value as a tool for long-term urinary drainage. Several new ideas on stent design, composition material and stent coating currently under evaluation, foreseen to eliminate the aforementioned drawbacks of ureteral stent usage. In this article we review the currently applied novel ideas and new designs of ureteral stents. Moreover, we evaluate potential future prospects of ureteral stent development adopted mostly by the pioneering cardiovascular stent industry, focusing, however, on the differences between ureteral and endothelial tissue. PMID:21789086

  7. Nanophasic biodegradation enhances the durability and biocompatibility of magnesium alloys for the next-generation vascular stents

    NASA Astrophysics Data System (ADS)

    Mao, Lin; Shen, Li; Niu, Jialin; Zhang, Jian; Ding, Wenjiang; Wu, Yu; Fan, Rong; Yuan, Guangyin

    2013-09-01

    Biodegradable metal alloys emerge as a new class of biomaterials for tissue engineering and medical devices such as cardiovascular stents. Deploying biodegradable materials to fabricate stents not only obviates a second surgical intervention for implant removal but also circumvents the long-term foreign body effect of permanent implants. However, these materials for stents suffer from an un-controlled degradation rate, acute toxic responses, and rapid structural failure presumably due to a non-uniform, fast corrosion process. Here we report that highly uniform, nanophasic degradation is achieved in a new Mg alloy with unique interstitial alloying composition as the nominal formula Mg-2.5Nd-0.2Zn-0.4Zr (wt%, hereafter, denoted as JDBM). This material exhibits highly homogeneous nanophasic biodegradation patterns as compared to other biodegradable metal alloy materials. Consequently it has significantly reduced degradation rate determined by electrochemical characterization. The in vitro cytotoxicity test using human vascular endothelial cells indicates excellent biocompatibility and potentially minimal toxic effect on arterial vessel walls. Finally, we fabricated a cardiovascular stent using JDBM and performed in vivo long-term assessment via implantation of this stent in an animal model. The results confirmed the reduced degradation rate in vivo, excellent tissue compatibility and long-term structural and mechanical durability. Thus, this new Mg-alloy with highly uniform nanophasic biodegradation represents a major breakthrough in the field and a promising material for manufacturing the next generation biodegradable vascular stents.

  8. Multifaceted prospects of nanocomposites for cardiovascular grafts and stents

    PubMed Central

    Vellayappan, Muthu Vignesh; Balaji, Arunpandian; Subramanian, Aruna Priyadarshini; John, Agnes Aruna; Jaganathan, Saravana Kumar; Murugesan, Selvakumar; Supriyanto, Eko; Yusof, Mustafa

    2015-01-01

    Cardiovascular disease is the leading cause of death across the globe. The use of synthetic materials is indispensable in the treatment of cardiovascular disease. Major drawbacks related to the use of biomaterials are their mechanical properties and biocompatibility, and these have to be circumvented before promoting the material to the market or clinical setting. Revolutionary advancements in nanotechnology have introduced a novel class of materials called nanocomposites which have superior properties for biomedical applications. Recently, there has been a widespread recognition of the nanocomposites utilizing polyhedral oligomeric silsesquioxane, bacterial cellulose, silk fibroin, iron oxide magnetic nanoparticles, and carbon nanotubes in cardiovascular grafts and stents. The unique characteristics of these nanocomposites have led to the development of a wide range of nanostructured copolymers with appreciably enhanced properties, such as improved mechanical, chemical, and physical characteristics suitable for cardiovascular implants. The incorporation of advanced nanocomposite materials in cardiovascular grafts and stents improves hemocompatibility, enhances antithrombogenicity, improves mechanical and surface properties, and decreases the microbial response to the cardiovascular implants. A thorough attempt is made to summarize the various applications of nanocomposites for cardiovascular graft and stent applications. This review will highlight the recent advances in nanocomposites and also address the need of future research in promoting nanocomposites as plausible candidates in a campaign against cardiovascular disease. PMID:25897223

  9. Multifaceted prospects of nanocomposites for cardiovascular grafts and stents.

    PubMed

    Vellayappan, Muthu Vignesh; Balaji, Arunpandian; Subramanian, Aruna Priyadarshini; John, Agnes Aruna; Jaganathan, Saravana Kumar; Murugesan, Selvakumar; Supriyanto, Eko; Yusof, Mustafa

    2015-01-01

    Cardiovascular disease is the leading cause of death across the globe. The use of synthetic materials is indispensable in the treatment of cardiovascular disease. Major drawbacks related to the use of biomaterials are their mechanical properties and biocompatibility, and these have to be circumvented before promoting the material to the market or clinical setting. Revolutionary advancements in nanotechnology have introduced a novel class of materials called nanocomposites which have superior properties for biomedical applications. Recently, there has been a widespread recognition of the nanocomposites utilizing polyhedral oligomeric silsesquioxane, bacterial cellulose, silk fibroin, iron oxide magnetic nanoparticles, and carbon nanotubes in cardiovascular grafts and stents. The unique characteristics of these nanocomposites have led to the development of a wide range of nanostructured copolymers with appreciably enhanced properties, such as improved mechanical, chemical, and physical characteristics suitable for cardiovascular implants. The incorporation of advanced nanocomposite materials in cardiovascular grafts and stents improves hemocompatibility, enhances antithrombogenicity, improves mechanical and surface properties, and decreases the microbial response to the cardiovascular implants. A thorough attempt is made to summarize the various applications of nanocomposites for cardiovascular graft and stent applications. This review will highlight the recent advances in nanocomposites and also address the need of future research in promoting nanocomposites as plausible candidates in a campaign against cardiovascular disease. PMID:25897223

  10. Angioplasty and Stenting of Symptomatic Vertebral Artery Stenosis

    PubMed Central

    Mohammadian, R.; Sharifipour, E.; Mansourizadeh, R.; Sohrabi, B.; Nayebi, A.R; Haririan, S.; Farhoudi, M.; Charsouei, S.; Najmi, S.

    2013-01-01

    Summary Percutaneous transluminal angioplasty (PTA) has recently become a noteworthy treatment option for significant stenosis involving the vertebral artery (VA) in selected patients. We conducted a prospective study to evaluate the efficacy, safety and mid-term follow up results of 206 cases received PTA with or without stent implant to treat their symptomatic atherosclerotic VA stenosis in all segments (V1-V4). In a prospective mono-arm trial from October 2008 to July 2012 in a single center, 239 lesions affecting the intra or extracranial VA (171 in V1, 17 in V2, 14 in V3, 21 in V4 and 16 in combined segments) were treated by PTA with or without stent implant. Non-disabling stroke patients who had failed conservative medical treatment and had angiographic evidence of >50% stenosis in the dominant VA with clinical signs and symptoms of VB stenosis were included in this study. They were mean followed for 13.15±5.24 months after treatment. Overall, 206 patients underwent the procedure. A stent was implemented in 199 patients (96.6%). The periprocedural complication rate was 7.2%. The procedural (technical) success rate was 97.6%. Of the total 239 lesions, 223 were treated with stent implant. Clinical success was achieved in all 206 symptomatic patients after the procedure. Restenosis occurred in 15.9% after a mean 10.8 (6-24) months. Of those, 63.1% and 34.2% had mild and moderate stenosis that was treated medically, whereas one case (2.6%) with severe restenosis underwent balloon angioplasty. No deaths occurred during the follow-up period. The follow-up complication rate was 6.3%. TIA occurred in 4.4%, a minor stroke in 1.4% and a major stroke in one patient. The overall patient event-free survival was 92.4%. These results demonstrate the safety and feasibility of PTA with or without stent implant, with a high technical success rate, a low complication rate, a low restenosis rate and durable clinical success in patients with symptomatic VA stenosis. This

  11. Bioresorbable microporous stents deliver recombinant adenovirus gene transfer vectors to the arterial wall.

    PubMed

    Ye, Y W; Landau, C; Willard, J E; Rajasubramanian, G; Moskowitz, A; Aziz, S; Meidell, R S; Eberhart, R C

    1998-01-01

    The use of intravascular stents as an adjunct for percutaneous transluminal revascularization is limited by two principal factors, acute thrombosis and neointimal proliferation, resulting in restenosis. To overcome these limitations, we have investigated the potential of microporous bioresorbable polymer stents formed from poly(L-lactic acid) (PLLA)/poly(epsilon-caprolactone) (PCL) blends to function both to provide mechanical support and as reservoirs for local delivery of therapeutic molecules and particles to the vessel wall. Tubular PLLA/PCL stents were fabricated by the flotation-precipitation method, and helical stents were produced by a casting/winding technique. Hybrid structures in which a tubular sheath is deposited on a helical skeleton were also generated. Using a two-stage solvent swelling technique, polyethylene oxide has been incorporated into these stents to improve hydrophilicity and water uptake, and to facilitate the ability of these devices to function as drug carriers. Stents modified in this manner retain axial and radial mechanical strength sufficient to stabilize the vessel wall against elastic recoil caused by vasoconstrictive and mechanical forces. Because of the potential of direct gene transfer into the vessel wall to ameliorate thrombosis and neointimal proliferation, we have investigated the capacity of these polymer stents to function in the delivery of recombinant adenovirus vectors to the vessel wall. In vitro, virus stock was observed to readily absorb into, and elute from these devices in an infectious form, with suitable kinetics. Successful gene transfer and expression has been demonstrated following implantation of polymer stents impregnated with a recombinant adenovirus carrying a nuclear-localizing betaGal reporter gene into rabbit carotid arteries. These studies suggest that surface-modified polymer stents may ultimately be useful adjunctive devices for both mechanical support and gene transfer during percutaneous

  12. Preclinical Study of a Biodegradable Polymer-based Stent with Abluminal Sirolimus Release

    PubMed Central

    Takimura, Celso Kiyochi; Campos, Carlos Augusto Homem M.; Melo, Pedro Henrique Magualhães Craveiro; Campos, Julliana Carvalho; Gutierrez, Paulo Sampaio; Borges, Thiago Francisco Costa; Curado, Luciano; Morato, Spero Penha; Laurindo, Francisco Rafael Martins; Lemos, Pedro Alves

    2014-01-01

    Background Bioabsorbable polymer stents with drug elution only on the abluminal surface may be safer than durable polymer drug-eluting stents. Objective To report the experimental findings with the InspironTM stent - a bioabsorbable polymer-coated stent with sirolimus release from the abluminal surface only, recently approved for clinical use. Methods 45 stents were implanted in the coronary arteries of 15 pigs. On day 28 after implantation, angiographic, intracoronary ultrasonographic and histomorphological data were collected. Five groups were analyzed: Group I (nine bare-metal stents); Group II (nine coated with bioabsorbable polymer on the luminal and abluminal surfaces); Group III (eight stents coated with bioabsorbable polymer on the abluminal surface); Group IV (nine stents with bioabsorbable polymer and sirolimus on the luminal and abluminal surfaces); and Group V (ten stents with bioabsorbable polymer and sirolimus only on the abluminal surface). Results The following results were observed for Groups I, II, III, IV and V, respectively: percentage stenosis of 29 ± 20; 36 ± 14; 33 ± 19; 22 ± 13 and 26 ± 15 (p = 0.443); late lumen loss (in mm) of 1.02 ± 0.60; 1.24 ± 0.48; 1.11 ± 0.54; 0.72 ± 0.44 and 0.78 ± 0.39 (p = 0.253); neointimal area (in mm2) of 2.60 ± 1.99; 2.74 ± 1.51; 2.74 ± 1.30; 1.30 ± 1.14 and 0.97 ± 0.84 (p = 0.001; Groups IV and V versus Groups I, II and III); and percentage neointimal area of 35 ± 25; 38 ± 18; 39 ± 19; 19 ± 18 and 15 ± 12 (p = 0.001; Groups IV and V versus Groups I, II and III). Injury and inflammation scores were low and with no differences between the groups. Conclusion The InspironTM stent proved to be safe and was able to significantly inhibit the neointimal hyperplasia observed on day 28 after implantation in porcine coronary arteries. PMID:24759951

  13. On Studying the Interaction Between Different Stent Models and Rabbit Tracheal Tissue: Numerical, Endoscopic and Histological Comparison.

    PubMed

    Chaure, J; Serrano, C; Fernández-Parra, R; Peña, E; Lostalé, F; De Gregorio, M A; Martínez, M A; Malvè, M

    2016-02-01

    Stenting technique is employed worldwide for treating atherosclerotic vessel and tracheal stenosis. Both diseases can be treated by means of metallic stents which present advantages but are affected by the main problem of restenosis of the stented area. In this study we have built a rabbit trachea numerical model and we have analyzed it before and after insertion and opening of two types of commercial stent: a Zilver(®) Flex™ Stent and a WallStent™. In experimental parallel work, two types of stent were implanted in 30 New Zealand rabbits divided in two groups of 10 animals corresponding to each stent type and a third group made up of 10 animals without stent. The tracheal wall response was assessed by means of computerized tomography by endoscopy, macroscopic findings and histopathological study 90 days after stent deployment. Three idealized trachea models, one model for each group, were created in order to perform the computational study. The animal model was used to validate the numerical findings and to attempt to find qualitative correlations between numerical and experimental results. Experimental findings such as inflammation, granuloma and abnormal tissue growth, assessed from histomorphometric analyses were compared with derived numerical parameters such as wall shear stress (WSS) and maximum principal stress. The direct comparison of these parameters and the biological response supports the hypothesis that WSS and tensile stresses may lead to a greater tracheal epithelium response within the stented region, with the latter seeming to have the dominant role. This study may be helpful for improving stent design and demonstrates the feasibility offered by in-silico investigated tracheal structural and fluid dynamics.

  14. On Studying the Interaction Between Different Stent Models and Rabbit Tracheal Tissue: Numerical, Endoscopic and Histological Comparison.

    PubMed

    Chaure, J; Serrano, C; Fernández-Parra, R; Peña, E; Lostalé, F; De Gregorio, M A; Martínez, M A; Malvè, M

    2016-02-01

    Stenting technique is employed worldwide for treating atherosclerotic vessel and tracheal stenosis. Both diseases can be treated by means of metallic stents which present advantages but are affected by the main problem of restenosis of the stented area. In this study we have built a rabbit trachea numerical model and we have analyzed it before and after insertion and opening of two types of commercial stent: a Zilver(®) Flex™ Stent and a WallStent™. In experimental parallel work, two types of stent were implanted in 30 New Zealand rabbits divided in two groups of 10 animals corresponding to each stent type and a third group made up of 10 animals without stent. The tracheal wall response was assessed by means of computerized tomography by endoscopy, macroscopic findings and histopathological study 90 days after stent deployment. Three idealized trachea models, one model for each group, were created in order to perform the computational study. The animal model was used to validate the numerical findings and to attempt to find qualitative correlations between numerical and experimental results. Experimental findings such as inflammation, granuloma and abnormal tissue growth, assessed from histomorphometric analyses were compared with derived numerical parameters such as wall shear stress (WSS) and maximum principal stress. The direct comparison of these parameters and the biological response supports the hypothesis that WSS and tensile stresses may lead to a greater tracheal epithelium response within the stented region, with the latter seeming to have the dominant role. This study may be helpful for improving stent design and demonstrates the feasibility offered by in-silico investigated tracheal structural and fluid dynamics. PMID:26589598

  15. Mis-sizing of stent promotes intimal hyperplasia: impact of endothelial shear and intramural stress

    PubMed Central

    Chen, Henry Y.; Sinha, Anjan K.; Choy, Jenny S.; Zheng, Hai; Sturek, Michael; Bigelow, Brian; Bhatt, Deepak L.

    2011-01-01

    Stent can cause flow disturbances on the endothelium and compliance mismatch and increased stress on the vessel wall. These effects can cause low wall shear stress (WSS), high wall shear stress gradient (WSSG), oscillatory shear index (OSI), and circumferential wall stress (CWS), which may promote neointimal hyperplasia (IH). The hypothesis is that stent-induced abnormal fluid and solid mechanics contribute to IH. To vary the range of WSS, WSSG, OSI, and CWS, we intentionally mismatched the size of stents to that of the vessel lumen. Stents were implanted in coronary arteries of 10 swine. Intravascular ultrasound (IVUS) was used to size the coronary arteries and stents. After 4 wk of stent implantation, IVUS was performed again to determine the extent of IH. In conjunction, computational models of actual stents, the artery, and non-Newtonian blood were created in a computer simulation to yield the distribution of WSS, WSSG, OSI, and CWS in the stented vessel wall. An inverse relation (R2 = 0.59, P < 0.005) between WSS and IH was found based on a linear regression analysis. Linear relations between WSSG, OSI, and IH were observed (R2 = 0.48 and 0.50, respectively, P < 0.005). A linear relation (R2 = 0.58, P < 0.005) between CWS and IH was also found. More statistically significant linear relations between the ratio of CWS to WSS (CWS/WSS), the products CWS × WSSG and CWS × OSI, and IH were observed (R2 = 0.67, 0.54, and 0.56, respectively, P < 0.005), suggesting that both fluid and solid mechanics influence the extent of IH. Stents create endothelial flow disturbances and intramural wall stress concentrations, which correlate with the extent of IH formation, and these effects were exaggerated with mismatch of stent/vessel size. These findings reveal the importance of reliable vessel and stent sizing to improve the mechanics on the vessel wall and minimize IH. PMID:21926337

  16. Development of a dynamic in vitro model of a stented blood vessel to evaluate the effects of stent strut material selection and surface coating on smooth muscle cell response

    NASA Astrophysics Data System (ADS)

    Winn, Bradley Huegh

    Cardiovascular disease is the leading cause of mortality in The United States and Europe, accounting for approximately half of all deaths. The most common form of cardiovascular disease is atherosclerosis, which is characterized by the formation of fatty atheromatous plaques that can grow to occlude the vessel lumen, thus causing ischemia distal to the occlusion. This is commonly treated using balloon angioplasty, which is usually done in conjunction with the deployment of a stent. Stent deployment helps hold the vessel open following the local injury caused by balloon inflation and prevents elastic recoil and subsequent negative remodeling. Stenting has been shown to significantly reduce restenosis rates from approximately 20-50% without a stent to about 10-30% with stent deployment. However, restenosis still remains the main cause of long-term stent failure. In basic terms, a balloon angioplasty procedure is a forceful displacement of an atherosclerotic lesion serving to widen the vessel lumen to increase blood flow. This procedure causes stretching of the vessel wall, tears in the atherosclerotic plaques, and general damage to the vessel in turn signaling a complex cascade of thrombosis, inflammation, intimal thickening, and vascular remodeling. Stent deployment also further complicates the immunological response by triggering a foreign body response from the implantation of a biomaterial into the body. When performing an angioplasty procedure, particularly in conjunction with stent deployment, a certain degree of vascular injury is inevitable. However, the initial injury can be further complicated by the body's local reaction to the implanted biomaterial, the severity of which can ultimately dictate the degree of restenosis and subsequently affect procedural success. The proliferative response of VSMCs to the various afore mentioned stimuli results in the formation of often copious amounts of neointimal tissue, generally known as intimal hyperplasia. The

  17. Current knowledge and future perspectives regarding stented valves.

    PubMed

    Santarpino, Giuseppe; Kalisnik, Jurij M; Fischlein, Theodor; Pfeiffer, Steffen

    2016-10-01

    Aortic valve bioprostheses are commonly implanted in the current era (also in younger patients) as they may obviate the need for anticoagulation while providing better hemodynamic performance and a more favorable quality of life. The steady increase in the use of biological valves has prompted the development of several different models of conventional stented bioprostheses. At present, there are four main types of stented aortic bioprostheses that compete in the market: the LivaNova Crown PRT (LivaNova Group, Burnaby, Canada), the St. Jude Medical Trifecta (St. Jude Medical, St. Paul, MN, USA), the Carpentier-Edwards Perimount Magna Ease (Edwards Lifesciences, Irvine, CA, USA), and the Medtronic Mosaic Ultra (Medtronic, Inc., Minneapolis, MN, USA). The purpose of this review is to describe the features of these bioprosthetic valve models and to compare the data provided by the manufacturers with those derived from the available literature. PMID:27575598

  18. Drug-eluting medical implants.

    PubMed

    Zilberman, Meital; Kraitzer, Amir; Grinberg, Orly; Elsner, Jonathan J

    2010-01-01

    Drug-eluting medical implants are actually active implants that induce healing effects, in addition to their regular task of support. This effect is achieved by controlled release of active pharmaceutical ingredients (API) into the surrounding tissue. In this chapter we focus on three types of drug-eluting devices: drug-eluting vascular stents, drug-eluting wound dressings and protein-eluting scaffolds for tissue regeneration, thus describing both internal and external implants. Each of these drug-eluting devices also presents an approach for solving the drug release issue. Most drug-eluting vascular stents are loaded with water-insoluble antiproliferative agents, and their diffusion from the device to the surrounding tissue is relatively slow. In contrast, most drug-eluting wound dressings are loaded with highly water-soluble antibacterial agents and the issue of fast release must therefore be addressed. Growth factor release from scaffolds for tissue regeneration offers a new approach of incorporating high-molecular-weight bioactive agents which are very sensitive to process conditions and preserve their activity during the preparation stage. The drug-eluting medical implants are described here in terms of matrix formats and polymers, incorporated drugs and their release profiles from the implants, and implant functioning. Basic elements, such as new composite core/shell fibers and structured films, can be used to build new antibiotic-eluting devices. As presented in this chapter, the effect of the processing parameters on the microstructure and the resulting drug release profiles, mechanical and physical properties, and other relevant properties, must be elucidated in order to achieve the desired properties. Newly developed implants and novel modifications of previously developed approaches have enhanced the tools available for creating clinically important biomedical applications.

  19. Stenting for malignant ureteral obstruction: Tandem, metal or metal-mesh stents.

    PubMed

    Elsamra, Sammy E; Leavitt, David A; Motato, Hector A; Friedlander, Justin I; Siev, Michael; Keheila, Mohamed; Hoenig, David M; Smith, Arthur D; Okeke, Zeph

    2015-07-01

    Extrinsic malignant compression of the ureter is not uncommon, often refractory to decompression with conventional polymeric ureteral stents, and frequently associated with limited survival. Alternative options for decompression include tandem ureteral stents, metallic stents and metal-mesh stents, though the preferred method remains controversial. We reviewed and updated our outcomes with tandem ureteral stents for malignant ureteral obstruction, and carried out a PubMed search using the terms "malignant ureteral obstruction," "tandem ureteral stents," "ipsilateral ureteral stents," "metal ureteral stent," "resonance stent," "silhouette stent" and "metal mesh stent." A comprehensive review of the literature and summary of outcomes is provided. The majority of studies encountered were retrospective with small sample sizes. The evidence is most robust for metal stents, whereas only limited data exists for tandem or metal-mesh stents. Metal and metal-mesh stents are considerably more expensive than tandem stenting, but the potential for less frequent stent exchanges makes them possibly cost-effective over time. Urinary tract infections have been associated with all stent types. A wide range of failure rates has been published for all types of stents, limiting direct comparison. Metal and metal-mesh stents show a high incidence of stent colic, migration and encrustation, whereas tandem stents appear to produce symptoms equivalent to single stents. Comparison is difficult given the limited evidence and heterogeneity of patients with malignant ureteral obstruction. It is clear that prospective, randomized studies are necessary to effectively scrutinize conventional, tandem, metallic ureteral and metal-mesh stents for their use in malignant ureteral obstruction.

  20. Biodegradable stents in gastrointestinal endoscopy

    PubMed Central

    Lorenzo-Zúñiga, Vicente; Moreno-de-Vega, Vicente; Marín, Ingrid; Boix, Jaume

    2014-01-01

    Biodegradable stents (BDSs) are an attractive option to avoid ongoing dilation or surgery in patients with benign stenoses of the small and large intestines. The experience with the currently the only BDS for endoscopic placement, made of Poly-dioxanone, have shown promising results. However some aspects should be improved as are the fact that BDSs lose their radial force over time due to the degradable material, and that can cause stent-induced mucosal or parenchymal injury. This complication rate and modest clinical efficacy has to be carefully considered in individual patients prior to placement of BDSs. Otherwise, the price of these stents therefore it is nowadays an important limitation. PMID:24605020

  1. Chronic impedance spectroscopy of an endovascular stent-electrode array

    NASA Astrophysics Data System (ADS)

    Opie, Nicholas L.; John, Sam E.; Rind, Gil S.; Ronayne, Stephen M.; Grayden, David B.; Burkitt, Anthony N.; May, Clive N.; O’Brien, Terence J.; Oxley, Thomas J.

    2016-08-01

    Objective. Recently, we reported a minimally invasive stent-electrode array capable of recording neural signals from within a blood vessel. We now investigate the use of electrochemical impedance spectroscopy (EIS) measurements to infer changes occurring to the electrode–tissue interface from devices implanted in a cohort of sheep for up to 190 days. Approach. In a cohort of 15 sheep, endovascular stent-electrode arrays were implanted in the superior sagittal sinus overlying the motor cortex for up to 190 days. EIS was performed routinely to quantify viable electrodes for up to 91 days. An equivalent circuit model (ECM) was developed from the in vivo measurements to characterize the electrode–tissue interface changes occurring to the electrodes chronically implanted within a blood vessel. Post-mortem histological assessment of stent and electrode incorporation into the wall of the cortical vessels was compared to the electrical impedance measurements. Main results. EIS could be used to infer electrode viability and was consistent with x-ray analysis performed in vivo, and post-mortem evaluation. Viable electrodes exhibited consistent 1 kHz impedances across the 91 day measurement period, with the peak resistance frequency for the acquired data also stable over time. There was a significant change in 100 Hz phase angles, increasing from ‑67.8° ± 8.8° at day 0 to ‑43.8° ± 0.8° at day 91, which was observed to stabilize after eight days. ECM’s modeled to the data suggested this change was due to an increase in the capacitance of the electrode–tissue interface. This was supported by histological assessment with >85% of the implanted stent struts covered with neointima and incorporated into the blood vessel within two weeks. Conclusion. This work demonstrated that EIS could be used to determine the viability of electrode implanted chronically within a blood vessel. Impedance measurements alone were not observed to be a useful predictor of alterations

  2. Chronic impedance spectroscopy of an endovascular stent-electrode array

    NASA Astrophysics Data System (ADS)

    Opie, Nicholas L.; John, Sam E.; Rind, Gil S.; Ronayne, Stephen M.; Grayden, David B.; Burkitt, Anthony N.; May, Clive N.; O'Brien, Terence J.; Oxley, Thomas J.

    2016-08-01

    Objective. Recently, we reported a minimally invasive stent-electrode array capable of recording neural signals from within a blood vessel. We now investigate the use of electrochemical impedance spectroscopy (EIS) measurements to infer changes occurring to the electrode-tissue interface from devices implanted in a cohort of sheep for up to 190 days. Approach. In a cohort of 15 sheep, endovascular stent-electrode arrays were implanted in the superior sagittal sinus overlying the motor cortex for up to 190 days. EIS was performed routinely to quantify viable electrodes for up to 91 days. An equivalent circuit model (ECM) was developed from the in vivo measurements to characterize the electrode-tissue interface changes occurring to the electrodes chronically implanted within a blood vessel. Post-mortem histological assessment of stent and electrode incorporation into the wall of the cortical vessels was compared to the electrical impedance measurements. Main results. EIS could be used to infer electrode viability and was consistent with x-ray analysis performed in vivo, and post-mortem evaluation. Viable electrodes exhibited consistent 1 kHz impedances across the 91 day measurement period, with the peak resistance frequency for the acquired data also stable over time. There was a significant change in 100 Hz phase angles, increasing from -67.8° ± 8.8° at day 0 to -43.8° ± 0.8° at day 91, which was observed to stabilize after eight days. ECM’s modeled to the data suggested this change was due to an increase in the capacitance of the electrode-tissue interface. This was supported by histological assessment with >85% of the implanted stent struts covered with neointima and incorporated into the blood vessel within two weeks. Conclusion. This work demonstrated that EIS could be used to determine the viability of electrode implanted chronically within a blood vessel. Impedance measurements alone were not observed to be a useful predictor of alterations occurring

  3. Endovascular Stents and Stent-Grafts: Is Heparin Coating Desirable?

    SciTech Connect

    Nelson, Stephen R.; Souza, Nandita M. de; Allison, David J.

    2000-07-15

    Heparins are glycosaminoglycans that, in addition to their anticoagulant activity, have interactions with growth factors and other glycoproteins. These interactions may stimulate neointimal hyperplasia when heparin is delivered locally on stents and stent-grafts. Modifying the structure of heparin to retain anticoagulant activity while minimizing these stimulatory effects on the vascular endothelium is desirable and may be achieved by understanding the relationships between the structure and function of the various parts of the heparin molecule.

  4. Drug delivery patterns for different stenting techniques in coronary bifurcations: a comparative computational study.

    PubMed

    Cutrì, Elena; Zunino, Paolo; Morlacchi, Stefano; Chiastra, Claudio; Migliavacca, Francesco

    2013-08-01

    The treatment of coronary bifurcation lesions represents a challenge for the interventional cardiologists due to the lower rate of procedural success and the higher risk of restenosis. The advent of drug-eluting stents (DES) has dramatically reduced restenosis and consequently the request for re-intervention. The aim of the present work is to provide further insight about the effectiveness of DES by means of a computational study that combines virtual stent implantation, fluid dynamics and drug release for different stenting protocols currently used in the treatment of a coronary artery bifurcation. An explicit dynamic finite element model is developed in order to obtain realistic configurations of the implanted devices used to perform fluid dynamics analysis by means of a previously developed finite element method coupling the blood flow and the intramural plasma filtration in rigid arteries. To efficiently model the drug release, a multiscale strategy is adopted, ranging from lumped parameter model accounting for drug release to fully 3-D models for drug transport to the artery. Differences in drug delivery to the artery are evaluated with respect to local drug dosage. This model allowed to compare alternative stenting configurations (namely the Provisional Side Branch, the Culotte and the Inverted Culotte techniques), thus suggesting guidelines in the treatment of coronary bifurcation lesions and addressing clinical issues such as the effectiveness of drug delivery to lesions in the side branch, as well as the influence of incomplete strut apposition and overlapping stents.

  5. Cochlear Implants.

    ERIC Educational Resources Information Center

    Clark, Catherine; Scott, Larry

    This brochure explains what a cochlear implant is, lists the types of individuals with deafness who may be helped by a cochlear implant, describes the process of evaluating people for cochlear implants, discusses the surgical process for implanting the aid, traces the path of sound through the cochlear implant to the brain, notes the costs of…

  6. One Year Clinical Outcomes of Renal Artery Stenting: The Results of ODORI Registry

    SciTech Connect

    Sapoval, M.; Tamari, I.; Goffette, P.; Downes, M.; Senechal, Q.; Fanelli, F.; Reimer, P.; Negaiwi, Z.; Cassin, P. De; Heye, S.; Korobov, V.; Tsetis, D.; Abada, H.

    2010-06-15

    The safety, efficacy and long term clinical benefits of renal artery revascularization by stenting are still a matter of debate. The aim of our study was to define the safety and efficacy of renal artery stenting with the Tsunami peripheral stent (Terumo Corporation, Tokyo, Japan). The ODORI was a prospective, multicentre registry which enrolled 251 consecutive patients, (276 renal arteries) in 36 centres across Europe. The primary endpoint was acute procedural success defined as <30% residual stenosis after stent placement. Secondary endpoints included major adverse events, blood pressure control, serum creatinine level, and target lesion revascularization (TLR) at 6 and 12 months. Patients were 70 {+-} 10 years old, 59% were male, 33% had diabetes, and 96% hypertension. The main indications for renal stent implantation were hypertension in 83% and renal salvage in 39%. Direct stent implantation was performed in 76% of the cases. Acute success rate was 100% with residual stenosis of 2.5 {+-} 5.4%. Systolic/diastolic blood pressure decreased from a mean of 171/89 at baseline to 142/78 mmHg at 6 months (p < 0.0001 vs. baseline), and 141/80 mmHg at 12 months (p < 0.0001 vs. baseline). Mean serum creatinine concentration did not change significantly in the total population. However, there was significant improvement in the highest tercile (from 283 {mu}mol/l at baseline to 205 and 209 {mu}mol/l at 6 and 12 months respectively). At 12-months, rates of restenosis and TLR were 6.6 and 0.8% respectively. The 12 month cumulative rate of all major clinical adverse events was 6.4% while the rate of device or procedure related events was 2.4%. In hypertensive patients with atherosclerotic renal artery stenosis Tsunami peripheral balloon-expandable stent provides a safe revascularization strategy, with a potential beneficial impact on hypertension control and renal function in the highest risk patients.

  7. Assessment of the trackability, flexibility, and conformability of coronary stents: a comparative analysis.

    PubMed

    Rieu, Régis; Barragan, Paul; Garitey, Vincent; Roquebert, Pierre O; Fuseri, Jean; Commeau, Philippe; Sainsous, Joel

    2003-08-01

    The efficacy and safety of coronary stent implantation depend on the mechanical features of these devices when deployed in atheromatous lesions of various morphologies. We evaluated the trackability, flexibility, and conformability of 17 coronary stents using specific mechanical bench tests. The quantifications used a dynamometer for assessment of trackability (maximal strength) and flexibility (stiffness) and a 3D optical gauging machine for assessment of conformability (distance between stent and arterial wall in a curvature). The maximal strength (measuring the trackability) ranged respectively from 0.24 +/- 0.06 and 0.38 +/- 0.03 N (Seaquest) to 1.31 +/- 0.42 and 1.34 +/- 0.35 N (Carbostent), concerning respectively curvatures of 90 degrees (P < 0.0001) and 135 degrees (P < 0.0001). The stiffness (measuring the flexibility) ranged from 0.53 +/- 0.16 (Seaquest) to 1.28 +/- 0.10 N/mm (NIR Royal; P < 0.0001). The mean distance between stent and external curvature (external conformability) ranged from 0.15 +/- 0.06 mm (S7) to 0.57 +/- 0.4 mm (NIR Royal; P < 0.0001). The mean distance between stent and internal curve (internal conformability) ranged from 0.26 +/- 0.13 (S7) to 0.44 +/- 0.12 mm (S670; P < 0.0001). These results may influence the choice of a particular stent adapted to a specific coronary anatomy. PMID:12891615

  8. CT virtual endoscopy and 3D stereoscopic visualisation in the evaluation of coronary stenting.

    PubMed

    Sun, Z; Lawrence-Brown

    2009-10-01

    The aim of this case report is to present the additional value provided by CT virtual endoscopy and 3D stereoscopic visualisation when compared with 2D visualisations in the assessment of coronary stenting. A 64-year old patient was treated with left coronary stenting 8 years ago and recently followed up with multidetector row CT angiography. An in-stent restenosis of the left coronary artery was suspected based on 2D axial and multiplanar reformatted images. 3D virtual endoscopy was generated to demonstrate the smooth intraluminal surface of coronary artery wall, and there was no evidence of restenosis or intraluminal irregularity. Virtual fly-through of the coronary artery was produced to examine the entire length of the coronary artery with the aim of demonstrating the intraluminal changes following placement of the coronary stent. In addition, stereoscopic views were generated to show the relationship between coronary artery branches and the coronary stent. In comparison with traditional 2D visualisations, virtual endoscopy was useful for assessment of the intraluminal appearance of the coronary artery wall following coronary stent implantation, while stereoscopic visualisation improved observers' understanding of the complex cardiac structures. Thus, both methods could be used as a complementary tool in cardiac imaging.

  9. Atomic layer deposition enhanced grafting of phosphorylcholine on stainless steel for intravascular stents.

    PubMed

    Zhong, Qi; Yan, Jin; Qian, Xu; Zhang, Tao; Zhang, Zhuo; Li, Aidong

    2014-09-01

    In-stent restenosis (ISR) and re-endothelialization delay are two major issues of intravascular stent in terms of clinical safety and effects. Construction of mimetic cell membrane surface on stents using phosphorylcholine have been regarded as one of the most powerful strategies to resolve these two issues and improve the performance of stents. In this study, atomic layer deposition (ALD) technology, which is widely used in semiconductor industry, was utilized to fabricate ultra-thin layer (10nm) of alumina (Al2O3) on 316L stainless steel (SS), then the alumina covered surface was modified with 3-aminopropyltriethoxysilane (APS) and 2-methacryloyloxyethyl phosphorylcholine (MPC) sequentially in order to produce phosphorylcholine mimetic cell membrane surface. The pristine and modified surfaces were characterized using X-ray photoelectron spectroscopy, atomic force microscope and water contact angle measurement. Furthermore, the abilities of protein adsorption, platelet adhesion and cell proliferation on the surfaces were investigated. It was found that alumina layer can significantly enhance the surface grafting of APS and MPC on SS; and in turn efficiently inhibit protein adsorption and platelet adhesion, and promote the attachment and proliferation of human umbilical vein endothelial cells (HUVEC) on the surfaces. In association with the fact that the deposition of alumina layer is also beneficial to the improvement of adhesion and integrity of drug-carrying polymer coating on drug eluting stents, we expect that ALD technology can largely assist in the modifications on inert metallic surfaces and benefit implantable medical devices, especially intravascular stents.

  10. Plaque components affect wall stress in stented human carotid artery: A numerical study

    NASA Astrophysics Data System (ADS)

    Fan, Zhen-Min; Liu, Xiao; Du, Cheng-Fei; Sun, An-Qiang; Zhang, Nan; Fan, Zhan-Ming; Fan, Yu-Bo; Deng, Xiao-Yan

    2016-09-01

    Carotid artery stenting presents challenges of in-stent restenosis and late thrombosis, which are caused primarily by alterations in the mechanical environment of the artery after stent implantation. The present study constructed patient-specific carotid arterial bifurcation models with lipid pools and calcified components based on magnetic resonance imaging. We numerically analyzed the effects of multicomponent plaques on the distributions of von Mises stresses (VMSs) in the patient-specific models after stenting. The results showed that when a stent was deployed, the large soft lipid pool in atherosclerotic plaques cushioned the host artery and reduced the stress within the arterial wall; however, this resulted in a sharp increase of VMS in the fibrous cap. When compared with the lipid pool, the presence of the calcified components led to slightly increased stresses on the luminal surface. However, when a calcification was located close to the luminal surface of the host artery and the stenosis, the local VMS was elevated. Overall, compared with calcified components, large lipid pools severely damaged the host artery after stenting. Furthermore, damage due to the calcified component may depend on location.

  11. Atomic layer deposition enhanced grafting of phosphorylcholine on stainless steel for intravascular stents.

    PubMed

    Zhong, Qi; Yan, Jin; Qian, Xu; Zhang, Tao; Zhang, Zhuo; Li, Aidong

    2014-09-01

    In-stent restenosis (ISR) and re-endothelialization delay are two major issues of intravascular stent in terms of clinical safety and effects. Construction of mimetic cell membrane surface on stents using phosphorylcholine have been regarded as one of the most powerful strategies to resolve these two issues and improve the performance of stents. In this study, atomic layer deposition (ALD) technology, which is widely used in semiconductor industry, was utilized to fabricate ultra-thin layer (10nm) of alumina (Al2O3) on 316L stainless steel (SS), then the alumina covered surface was modified with 3-aminopropyltriethoxysilane (APS) and 2-methacryloyloxyethyl phosphorylcholine (MPC) sequentially in order to produce phosphorylcholine mimetic cell membrane surface. The pristine and modified surfaces were characterized using X-ray photoelectron spectroscopy, atomic force microscope and water contact angle measurement. Furthermore, the abilities of protein adsorption, platelet adhesion and cell proliferation on the surfaces were investigated. It was found that alumina layer can significantly enhance the surface grafting of APS and MPC on SS; and in turn efficiently inhibit protein adsorption and platelet adhesion, and promote the attachment and proliferation of human umbilical vein endothelial cells (HUVEC) on the surfaces. In association with the fact that the deposition of alumina layer is also beneficial to the improvement of adhesion and integrity of drug-carrying polymer coating on drug eluting stents, we expect that ALD technology can largely assist in the modifications on inert metallic surfaces and benefit implantable medical devices, especially intravascular stents. PMID:25016426

  12. Treatment of Benign Tracheal Stenosis Utilizing Self-Expanding Nitinol Stents

    SciTech Connect

    Sesterhenn, Andreas M. Wagner, Hans-Joachim; Alfke, Heiko; Werner, Jochen A.; Lippert, Burkard M.

    2004-08-15

    We assessed the results of self-expanding metallic stent insertion into benign proximal tracheal stenosis in patients not appropriate or unfit for surgical repair. Proximal benign tracheal stenoses had occurred in 11 patients (7 men, 4 women, mean age 68.8 years) after long-time intubation (n = 6), tracheostomy (n = 4), or chondropathia (n = 1). Fourteen self-expanding nitinol stents were placed in the patients under general anesthesia with endoscopical and fluoroscopical guidance. Stent insertion was successful in all cases and led to immediate relief of the morphological and functional airway obstruction. No immediate complications were noted. During the mean follow-up period of 67.5 weeks we observed one recurrent dyspnea 3 months after implantation and granuloma formation at the stent insertion site in another patient. Both complications were successfully treated with additional stent insertion in one case and laser resection of granulomas in the other. Self-expanding nitinol stents should be considered for the treatment of benign proximal tracheal obstruction in selected patients for whom surgical repair is contraindicated.

  13. Long-term clinical outcomes of drug-eluting stents vs. bare-metal stents in Chinese geriatric patients

    PubMed Central

    Chan, Pak-Hei; Liu, Sha-Sha; Tse, Hung-Fat; Chow, Wing-Hing; Jim, Man-Hong; HO, Hee-Hwa; Siu, Chung Wah

    2013-01-01

    Background & objective Little is known about the relative efficacies of percutaneous coronary intervention (PCI) with drug-eluting stents (DES) and bare-metal stents (BMS) in elderly patients. The objective of this study was to evaluate the clinical outcome for geriatric patients who received either DES or BMS. Methods From January 2002 to October 2005, 199 consecutive Chinese geriatric patients (≥ 75 years old) underwent PCI with coronary DES or BMS implantation at our institution. We analyzed the major clinical end points that included all-cause mortality, cardiovascular death, myocardial infarction, target lesion revascularization (TLR), stent thrombosis, and bleeding complications. Results The three-year cumulative rates of all-cause mortality, cardiovascular death, and myocardial infarction were significantly lower in the DES group (6.3%, 3.6%, 5.4%) compared with the BMS group (16.2%, 11.5%, 14.9%; P < 0.05). No significant differences were found in the three-year cumulative rate for target lesion revascularization (6.3% vs. 4.6%, P = 0.61) or stent thrombosis (3.6% vs. 2.3%, P = 0.70). Likewise, there were no statistically significant differences in the cumulative rate for intracranial hemorrhage, or major and minor hemorrhage at three years. Conclusions DES-based PCI was associated with a significant reduction in the three-year cumulative rate of all-cause mortality, cardiovascular death, and myocardial infarction compared with BMS, without increased risk of TLR, stent thrombosis, or bleeding complications at three years in this group of Chinese geriatric patients. PMID:24454325

  14. Impact of Stent Design on Intra-Aneurysmal Flow

    PubMed Central

    Ohta, M.; Hirabayashi, M.; Wetzel, S.; Lylyk, P.; Wata, H.; Tsutsumi, S.; Rüfenacht, D.A.

    2004-01-01

    Summary In addition to providing a skeleton for vessel reconstruction, stent implantation as used for cerebral aneurysm treatment can induce flow redirection, thus reducing vortical flow velocities within the aneurysm cavity. Further, stent characteristics such as strut size, porosity and cell shape influence the changes in intra-aneurysmal flow by analog simulations. The purpose of this computer simulation study was to visualize the flow pattern over the entire neck area of a side wall aneurysm while changing the stent parameters. A 3-D computer model aneurysm was constructed to have a parent artery of 5 mm diameter and an aneurysm of 10 mm diameter. The distance between the midline of main artery and center point of the aneurysm was 6.8 mm, providing a neck length of 5 mm, a width of 3.6 mm, and a neck area of 14 mm 2. The simulations were carried out with a Finite Element Method based flow simulation package. The incompressible Navier-Stokes equation was solved for a steady flow with a mean speed of 290 mm/s, steady viscosity of 3.83 cp, and density of 1.0 g/cm3. Two parallel stent struts (dimensions: 100 µm m 100 µm m 2.0 mm) were introduced into the plane of the aneurysm neck. The fraction of the aneurysm neck cross-section occupied by the stent was 2.83% in all cases. The velocity distribution through the neck of the aneurysm was calculated for three different choices of separation between the struts for each of two orientations of the struts (parallel and perpendicular) relative to the vessel axis. The flow pattern in the aneurysm was composed of an inflow zone at the distal neck and of an outflow zone at the proximal neck. The placement of stent struts at the aneurysm neck resulted in a decrease in the mean speed in the aneurysm. The degree of reduction and the distribution of flow through the neck did depend on the orientation of the stent struts. The struts, when placed parallel or perpendicular to the parent vessel axis affected the mean speed through

  15. Percutaneous cholangioscopy in obstructed biliary metal stents

    SciTech Connect

    Hausegger, Klaus A.; Mischinger, Hans J.; Karaic, Radenko; Klein, Guenther E.; Kugler, Cristian; Kern, Robert; Uggowitzer, Martin; Szolar, Dieter

    1997-05-15

    Purpose. To reevaluate the reasons for the occlusion of self-expanding biliary metal stents, on the basis of cholangioscopic findings. Methods. Percutaneous transhepatic cholangioscopy (PTCS) was performed in 15 patients with obstructed biliary Wallstents. The reason for stent insertion was a malignant obstruction in 14 patients; 1 had a benign biliary stricture. Conventional noncovered stents had been inserted in 12 patients; in 3 cases a polyurethane-covered prototype Wallstent had been used. Stent occlusions occurred after 1-55 months. PTCS was performed with a 2.3-mm endoscope through an 11 Fr sheath. Biopsies were taken via the working channel of the endoscope. Results. In all patients with noncovered stents the inner surface of the stent was highly irregular with seaweed-like protrusions (biopsy-proven granulation tissue). Stent incorporation varied from absent (n=1) to subtotal (n=8), but was always incomplete, no matter how long the stent had been in place. Tumor ingrowth was histologically proven in 2 patients. One patient had a large occluding concrement at the proximal end of the stent. In patients with covered stents, the inner surface appeared more regular; however, viable granulation tissue was found inside two stents and tumor ingrowth in one of them. Conclusion. PTCS showed that incorporation of the stent is virtually always incomplete. The factors contributing most to stent occlusion are the buildup of granulation tissue, bile sludge, and tumor overgrowth. Stone formation and tumor ingrowth can also be important, although less common causes of occlusion. A polyurethane stent covering could not prevent tumor ingrowth in one patient and the buildup of viable granulation tissue inside the stent in two further patients; mean stent patency in the three patients with such a stent was 3 months.

  16. Five factors and three characteristics of coronary in-stent restenosis

    PubMed Central

    2015-01-01

    In the field of interventional cardiology, several patient subsets still present with poor clinical and angiographic outcomes after drug-eluting stent (DES) implantation. The author of this editorial comment supports the idea that in-stent restenosis (ISR) includes three characteristics (severity and extent of stenosis, and tissue characteristics) that are caused by five factors (device, patient, anatomy, procedure, and history). To reduce further revascularization, a tailor-made strategy may be considered in accordance with the factors and characteristics of the individual ISR lesion. PMID:26793374

  17. Emergency Renal Ablation for Life-Threatening Hemorrhage from Multiple Capsular Branches During Renal Artery Stenting

    SciTech Connect

    Aytekin, Cuneyt Yildirim, Utku M.; Ozyer, Umut; Harman, Ali; Boyvat, Fatih

    2010-06-15

    A 55-year-old woman underwent bilateral renal artery stent placement with good angiographic result. After the procedure, the patient complained of left flank pain secondary to subcapsular hematoma. Retrospective evaluation of images taken during stent implantation favored the diagnosis of guidewire perforation. Three hours after the procedure, contrast-enhanced computed tomography and subsequent renal angiography showed multifocal extravasations. We performed emergent renal ablation for the treatment of massive bleeding. To our knowledge, this is the first use of transcatheter renal ablation technique for this purpose.

  18. Endovascular Stent-Graft Repair as a Late Secondary Procedure After Previous Aortic Grafts

    SciTech Connect

    Matsagas, Miltiadis I. Anagnostopoulos, Constantine E.; Papakostas, John C.; DeRose, Joseph J.; Siminelakis, Stavros; Katsouras, Christos S.; Toumpoulis, Ioannis K.; Drossos, George E.; Michalis, Lampros K.

    2006-08-15

    Thoracic and abdominal aortic endovascular procedures as alternatives to aortic reoperations were studied in three different cases. An anastomotic aneurysm after previous thoracic aortic graft for coarctation, a second-stage elephant trunk repair (descending thoracic aortic aneurysm), and a secondary aneurysm proximal to a previous abdominal aortic graft were successfully treated with endovascular stent-grafts. During the follow-up period no lethal events or major aortic or graft-related complications were observed, except a type II endoleak in the anastomotic aortic aneurysm case. An endovascular stent-graft can be safely deployed into a previously implanted vascular graft, avoiding repeat surgery.

  19. Compression, distortion and dislodgement of large caliber stents in congenital heart defects caused by cardiopulmonary resuscitation: a case series and review of the literature.

    PubMed

    Haas, Nikolaus A; Happel, Christoph M; Jategaonkar, Smita; Moysich, Axel; Hanslik, Andreas; Kececioglu, Deniz; Sandica, Eugen; Laser, Kai Thorsten

    2014-09-01

    Stenting of vascular, extracardiac or lately intracardiac stenosis has become an established interventional treatment for a variety of problems in congenital or acquired heart disease. Most stent procedures are completed successfully and the long-term outcome is favorable in the majority of cases. Stent collapse or deformation is a well recognized entity in peripheral stents and can be attributed to insufficient radial force; it can also be attributed to excessive external forces, like deformation of stents in the right ventricular outflow tract, where external compression is combined with continuous movement caused by the beating heart. The protection of the thoracic cage may prove to be insufficient in extraordinary circumstances, such as chest compression in trauma or cardiopulmonary resuscitation (CPR). In this case series, we describe three patients in whom large endovascular stents were placed to treat significant stenosis of the aorta, the aortic arch or the venous system of the inferior vena cava close to the atrium. In all patients, CPR was necessary during their clinical course for various reasons; after adequate CPR, including appropriate chest compression all patients survived the initial resuscitation phase. Clinical, echocardiographic as well as radiologic re-evaluation after resuscitation revealed significant stent distortion, compression, displacement or additional vascular injury. The possibility of mechanical deformation of large endovascular stents needs to be considered and recognized when performing CPR; if CPR is successful, immediate re-evaluation of the implanted stents--if possible by biplane fluoroscopy--seems mandatory.

  20. Automated volumetric stent analysis of in-vivo intracoronary optical coherence tomography three-dimensional datasets

    NASA Astrophysics Data System (ADS)

    Ughi, Giovanni J.; Adriaenssens, Tom; Onsea, Kevin; Dubois, Christophe; Coosemans, Mark; Sinnaeve, Peter; Desmet, Walter; D'hooge, Jan

    2011-06-01

    Intra-vascular Optical Coherence Tomography (IV-OCT) is an appropriate imaging modality for the evaluation of stent struts apposition and coverage in the coronary arteries. Most often, image analysis is performed by a time-consuming manual contour tracing process. Recently, we proposed an algorithm for fully automated lumen morphology and individual stent struts apposition/coverage quantification. In this manuscript further developments allowing for automatic segmentation of the stent contour are presented. As such, quantification of in-stent area, malapposition cross-sectional area (i.e. the area representing the space from the stent surface to the vessel wall) and coverage cross-sectional area (i.e. the area of the tissue covering the stent surface) are automatically obtained. Volumetric measurements of malapposition and coverage are then achieved through the analysis of equally-spaced consecutive IV-OCT cross-sectional images. In addition, uncovered and malapposed struts are automatically clustered through consecutive slices according to their three-dimensional spatial position. Finally, properties of each cluster (e.g. malapposition/coverage volumes and struts spatial location and distribution) are quantified allowing for a volumetric analysis of the implanted device. Validation of the algorithm was obtained taking as a reference manual measurements performed by an expert cardiologist. 102 in-vivo images, taken at random from 8 different patients, were both automatically and manually analyzed quantifying lumen and stent area. High Pearson's correlation coefficients (Rarea = 0.99) and Bland-Altman statistics, showing no significant bias and good limits of agreement, proved that the presented algorithm provides a robust and fast tool to automatically estimate apposition and coverage of stent through an entire in-vivo IV-OCT pullback. Such a tool will be important for the integration of this technology in clinical routine and large clinical trials.

  1. Investigating the flow dynamics in the obstructed and stented ureter by means of a biomimetic artificial model.

    PubMed

    Clavica, Francesco; Zhao, Xuefeng; ElMahdy, Motaz; Drake, Marcus J; Zhang, Xunli; Carugo, Dario

    2014-01-01

    Double-J stenting is the most common clinical method employed to restore the upper urinary tract drainage, in the presence of a ureteric obstruction. After implant, stents provide an immediate pain relief by decreasing the pressure in the renal pelvis (P). However, their long-term usage can cause infections and encrustations, due to bacterial colonization and crystal deposition on the stent surface, respectively. The performance of double-J stents - and in general of all ureteric stents - is thought to depend significantly on urine flow field within the stented ureter. However very little fundamental research about the role played by fluid dynamic parameters on stent functionality has been conducted so far. These parameters are often difficult to assess in-vivo, requiring the implementation of laborious and expensive experimental protocols. The aim of the present work was therefore to develop an artificial model of the ureter (i.e. ureter model, UM) to mimic the fluid dynamic environment in a stented ureter. The UM was designed to reflect the geometry of pig ureters, and to investigate the values of fluid dynamic viscosity (μ), volumetric flow rate (Q) and severity of ureteric obstruction (OB%) which may cause critical pressures in the renal pelvis. The distributed obstruction derived by the sole stent insertion was also quantified. In addition, flow visualisation experiments and computational simulations were performed in order to further characterise the flow field in the UM. Unique characteristics of the flow dynamics in the obstructed and stented ureter have been revealed with using the developed UM. PMID:24498322

  2. Investigating the Flow Dynamics in the Obstructed and Stented Ureter by Means of a Biomimetic Artificial Model

    PubMed Central

    Clavica, Francesco; Zhao, Xuefeng; ElMahdy, Motaz; Drake, Marcus J.; Zhang, Xunli; Carugo, Dario

    2014-01-01

    Double-J stenting is the most common clinical method employed to restore the upper urinary tract drainage, in the presence of a ureteric obstruction. After implant, stents provide an immediate pain relief by decreasing the pressure in the renal pelvis (P). However, their long-term usage can cause infections and encrustations, due to bacterial colonization and crystal deposition on the stent surface, respectively. The performance of double-J stents - and in general of all ureteric stents - is thought to depend significantly on urine flow field within the stented ureter. However very little fundamental research about the role played by fluid dynamic parameters on stent functionality has been conducted so far. These parameters are often difficult to assess in-vivo, requiring the implementation of laborious and expensive experimental protocols. The aim of the present work was therefore to develop an artificial model of the ureter (i.e. ureter model, UM) to mimic the fluid dynamic environment in a stented ureter. The UM was designed to reflect the geometry of pig ureters, and to investigate the values of fluid dynamic viscosity (μ), volumetric flow rate (Q) and severity of ureteric obstruction (OB%) which may cause critical pressures in the renal pelvis. The distributed obstruction derived by the sole stent insertion was also quantified. In addition, flow visualisation experiments and computational simulations were performed in order to further characterise the flow field in the UM. Unique characteristics of the flow dynamics in the obstructed and stented ureter have been revealed with using the developed UM. PMID:24498322

  3. Effects of Methotrexate in a Rabbit Model of In-Stent Neoatherosclerosis: An Optical Coherence Tomography Study.

    PubMed

    Zhang, Ruoxi; Chen, Shuyuan; Zhang, Hui; Liu, Qi; Xing, Jianpang; Zhao, Qi; Wang, Yu; Yu, Bo; Hou, Jingbo

    2016-01-01

    This study used optical coherence tomography (OCT) to investigate the effects of systemic methotrexate, in combination with a drug-eluting stent, on in-stent neoatherosclerosis in a rabbit model. Sirolimus-eluting stents were surgically implanted in the right common carotid arteries of 200 male New Zealand White rabbits; the animals received a high-fat diet, beginning one week before stent implantation. Each animal was randomly assigned to 1 of 4 groups, receiving intravenous injections of either methotrexate (0.4 mg/kg) or placebo weekly for 4 or 12 weeks. Stented arterial segments were harvested after stenting for 4 or 12 weeks, and processed for OCT and histological analysis. Prior to harvesting the arterial segments, blood was collected for the determinations of cytokine levels. Compared with the control animals, the methotrexate-treated animals showed lower rates of lipid-rich intima and per-strut low-signal intensity layers, smaller neointimal areas, and reduced neointimal thickness; larger fibrous cap thicknesses and smaller lumen areas were also seen in the animals receiving methotrexate. The levels of serum interleukin, adhesion molecules, and nuclear factor-κB p65 decreased and IL-10 level increased in the methotrexate-treated animals. Targeting the pro-inflammatory pathways may be an effective way to prevent restenosis without the long-term risk of late thrombosis. PMID:27644847

  4. Effects of Methotrexate in a Rabbit Model of In-Stent Neoatherosclerosis: An Optical Coherence Tomography Study.

    PubMed

    Zhang, Ruoxi; Chen, Shuyuan; Zhang, Hui; Liu, Qi; Xing, Jianpang; Zhao, Qi; Wang, Yu; Yu, Bo; Hou, Jingbo

    2016-09-20

    This study used optical coherence tomography (OCT) to investigate the effects of systemic methotrexate, in combination with a drug-eluting stent, on in-stent neoatherosclerosis in a rabbit model. Sirolimus-eluting stents were surgically implanted in the right common carotid arteries of 200 male New Zealand White rabbits; the animals received a high-fat diet, beginning one week before stent implantation. Each animal was randomly assigned to 1 of 4 groups, receiving intravenous injections of either methotrexate (0.4 mg/kg) or placebo weekly for 4 or 12 weeks. Stented arterial segments were harvested after stenting for 4 or 12 weeks, and processed for OCT and histological analysis. Prior to harvesting the arterial segments, blood was collected for the determinations of cytokine levels. Compared with the control animals, the methotrexate-treated animals showed lower rates of lipid-rich intima and per-strut low-signal intensity layers, smaller neointimal areas, and reduced neointimal thickness; larger fibrous cap thicknesses and smaller lumen areas were also seen in the animals receiving methotrexate. The levels of serum interleukin, adhesion molecules, and nuclear factor-κB p65 decreased and IL-10 level increased in the methotrexate-treated animals. Targeting the pro-inflammatory pathways may be an effective way to prevent restenosis without the long-term risk of late thrombosis.

  5. Effects of Methotrexate in a Rabbit Model of In-Stent Neoatherosclerosis: An Optical Coherence Tomography Study

    PubMed Central

    Zhang, Ruoxi; Chen, Shuyuan; Zhang, Hui; Liu, Qi; Xing, Jianpang; Zhao, Qi; Wang, Yu; Yu, Bo; Hou, Jingbo

    2016-01-01

    This study used optical coherence tomography (OCT) to investigate the effects of systemic methotrexate, in combination with a drug-eluting stent, on in-stent neoatherosclerosis in a rabbit model. Sirolimus-eluting stents were surgically implanted in the right common carotid arteries of 200 male New Zealand White rabbits; the animals received a high-fat diet, beginning one week before stent implantation. Each animal was randomly assigned to 1 of 4 groups, receiving intravenous injections of either methotrexate (0.4 mg/kg) or placebo weekly for 4 or 12 weeks. Stented arterial segments were harvested after stenting for 4 or 12 weeks, and processed for OCT and histological analysis. Prior to harvesting the arterial segments, blood was collected for the determinations of cytokine levels. Compared with the control animals, the methotrexate-treated animals showed lower rates of lipid-rich intima and per-strut low-signal intensity layers, smaller neointimal areas, and reduced neointimal thickness; larger fibrous cap thicknesses and smaller lumen areas were also seen in the animals receiving methotrexate. The levels of serum interleukin, adhesion molecules, and nuclear factor-κB p65 decreased and IL-10 level increased in the methotrexate-treated animals. Targeting the pro-inflammatory pathways may be an effective way to prevent restenosis without the long-term risk of late thrombosis. PMID:27644847

  6. Dental Implants

    MedlinePlus

    ... Procedures Dental Implants Dentures Direct Bonding Implants versus Bridges Orthodontics and Aligners Periodontal Plastic Surgery Porcelain Crowns Porcelain Fixed Bridges Porcelain Veneers Repairing Chipped Teeth Teeth Whitening Tooth- ...

  7. Mechanisms of Biliary Plastic Stent Occlusion and Efforts at Prevention

    PubMed Central

    Kwon, Chang-Il; Lehman, Glen A.

    2016-01-01

    Biliary stenting via endoscopic retrograde cholangiopancreatography has greatly improved the quality of patient care over the last 30 years. Plastic stent occlusion limits the life span of such stents. Attempts to improve plastic stent patency duration have mostly failed. Metal stents (self-expandable metal stents [SEMSs]) have therefore replaced plastic stents, especially for malignant biliary strictures. SEMS are at least 10 times more expensive than plastic stents. In this focused review, we will discuss basic mechanisms of plastic stent occlusion, along with a systematic summary of previous efforts and related studies to improve stent patency and potential new techniques to overcome existing limitations. PMID:27000422

  8. Transjugular Portal Venous Stenting in Inflammatory Extrahepatic Portal Vein Stenosis

    SciTech Connect

    Schaible, Rolf; Textor, Jochen; Decker, Pan; Strunk, Holger; Schild, Hans

    2002-12-15

    We report the case of a 37-year-old man with necrotizing pancreatitis associated with inflammatory extrahepatic portal vein stenosis and progressive ascites. Four months after the acute onset, when no signs of infection were present, portal decompression was performed to treat refractory ascites. Transjugulartranshepatic venoplasty failed to dilate the stenosis in the extrahepatic portion of the portal vein sufficiently. Therefore a Wallstent was implanted, resulting in almost normal diameter of the vessel. In follow-up imaging studies the stent and the portal vein were still patent 12 months after the intervention and total resolution of the ascites was observed.

  9. Dialysis access pseudoaneurysm: endovascular treatment with a covered stent

    PubMed Central

    Centola, Marco; Ferraresi, Roberto; Danzi, Gian B

    2010-01-01

    Iatrogenic pseudoaneurysms of the brachial artery are rare complications of haemodialysis access procedures and can lead to substantial morbidity and mortality if not managed promptly; however, surgery is also associated with the potential risk of severe complications. We describe the clinical and radiological findings relating to a dialysed patient who developed a huge iatrogenic pseudoaneurysm of the brachial artery (due to an inadvertent artery puncture), which was successfully treated by means of the percutaneous implantation of a polytetrafluoroethylene (PTFE)-covered stent. PMID:22778110

  10. The Development of Carotid Stent Material

    PubMed Central

    He, Dongsheng; Liu, Wenhua; Zhang, Tao

    2015-01-01

    Endovascular angioplasty with stenting is a promising option for treating carotid artery stenosis. There exist a rapidly increasing number of different stent types with different materials. The bare-metal stent is the most commonly used stent with acceptable results, but it leaves us with the problems of thrombosis and restenosis. The drug-eluting stent is a breakthrough as it has the ability to reduce the restenosis rate, but the problem of late thrombosis still has to be addressed. The biodegradable stent disappears after having served its function. However, restenosis and degradation rates remain to be studied. In this article, we review every stent material with its characteristics, clinical results and complications and point out the standards of an ideal carotid stent. PMID:26019710

  11. Angioplasty and stent placement - carotid artery

    MedlinePlus

    Carotid angioplasty and stenting; CAS; Angioplasty - carotid artery; Carotid artery stenosis - angioplasty; ... Carotid angioplasty and stenting (CAS) is done using a small surgical cut. Your surgeon will make a surgical cut ...

  12. Restenosis of the CYPHER-Select, TAXUS-Express, and Polyzene-F Nanocoated Cobalt-Chromium Stents in the Minipig Coronary Artery Model

    SciTech Connect

    Radeleff, Boris Thierjung, Heidi; Stampfl, Ulrike; Stampfl, Sibylle; Lopez-Benitez, Ruben; Sommer, Christof; Berger, Irina; Richter, Goetz M.

    2008-09-15

    PurposeTo date no direct experimental comparison between the CYPHER-Select and TAXUS-Express stents is available. Therefore, we investigated late in-stent stenosis, thrombogenicity, and inflammation, comparing the CYPHER-Select, TAXUS-Express, and custom-made cobalt chromium Polyzene-F nanocoated stents (CCPS) in the minipig coronary artery model.MethodsThe three stent types were implanted in the right coronary artery of 30 minipigs. The primary endpoint was in-stent stenosis assessed by quantitative angiography and microscopy. Secondary endpoints were inflammation and thrombogenicity evaluated by scores for inflammation and immunoreactivity (C-reactive protein and transforming growth factor beta). Follow-up was at 4 and 12 weeks.ResultsStent placement was successful in all animals; no thrombus deposition occurred. Quantitative angiography did not depict statistically significant differences between the three stent types after 4 and 12 weeks. Quantitative microscopy at 4 weeks showed a statistically significant thicker neointima (p = 0.0431) for the CYPHER (105.034 {+-} 62.52 {mu}m) versus the TAXUS (74.864 {+-} 66.03 {mu}m) and versus the CCPS (63.542 {+-} 39.57 {mu}m). At 12 weeks there were no statistically significant differences. Inflammation scores at 4 weeks were significantly lower for the CCPS and CYPHER compared with the TAXUS stent (p = 0.0431). After 12 weeks statistical significance was only found for the CYPHER versus the TAXUS stent (p = 0.0431). The semiquantitative immunoreactivity scores for C-reactive protein and transforming growth factor beta showed no statistically significant differences between the three stent types after 4 and 12 weeks.ConclusionsThe CCPS provided effective control of late in-stent stenosis and thrombogenicity in this porcine model compared with the two drug-eluting stents. Its low inflammation score underscores its noninflammatory potential and might explain its equivalence to the two DES.

  13. Fluid mechanics in stented arterial model

    NASA Astrophysics Data System (ADS)

    Bernad, S. I.; Totorean, A.; Bosioc, A.; Crainic, N.; Hudrea, C.; Bernad, E. S.

    2015-12-01

    Local hemodynamic factors are known affect the natural history of the restenosis critically after coronary stenting of atherosclerosis. Stent-induced flows disturbance magnitude dependent directly on the strut design. Strut shape, strut thickness and the distance between consecutive struts have been associated clinically with the with post-intervention clinical outcomes. Hemodynamically favorable designs according to computational modeling can reduced in-stent restenosis after coronary stenting intervention.

  14. Repositioning of Covered Stents: The Grip Technique

    SciTech Connect

    Kirby, John Martin; Guo Xiaofeng; Midia, Mehran

    2011-06-15

    Introduction: Retrieval and repositioning of a stent deployed beyond its intended target region may be a difficult technical challenge. Materials and Methods: A balloon-mounted snare technique, a variant of the coaxial loop snare technique, is described. Results: The technique is described for the repositioning of a covered transjugular intrahepatic portosystemic shunt stent and a covered biliary stent. Conclusion: The balloon-mounted snare technique is a useful technique for retrieval of migrated stents.

  15. A Comprehensive Review of Esophageal Stents

    PubMed Central

    Hong, Jinwha; Lam-Tsai, Yvette; Gress, Frank

    2012-01-01

    Esophageal stents are important tools for palliative treatment of inoperable esophageal malignancies. With the development of multiple self-expandable stents, there are now several therapeutic options for managing benign and malignant esophageal diseases. This paper discusses the various types of esophageal stents currently available, indications for their placement, challenges and complications that gastroenterologists face when placing these stents, and some of the innovations that will become available in the near future. PMID:23293566

  16. Carotid Artery Stenting versus Endarterectomy

    PubMed Central

    Gahremanpour, Amir; Perin, Emerson C.; Silva, Guilherme

    2012-01-01

    For about 2 decades, investigators have been comparing carotid endarterectomy with carotid artery stenting in regard to their effectiveness and safety in treating carotid artery stenosis. We conducted a systematic review to summarize and appraise the available evidence provided by randomized trials, meta-analyses, and registries comparing the clinical outcomes of the 2 procedures. We searched the MEDLINE, SciVerse Scopus, and Cochrane databases and the bibliographies of pertinent textbooks and articles to identify these studies. The results of clinical trials and, consequently, the meta-analyses of those trials produced conflicting results regarding the comparative effectiveness and safety of carotid endarterectomy and carotid stenting. These conflicting results arose because of differences in patient population, trial design, outcome measures, and variability among centers in the endovascular devices used and in operator skills. Careful appraisal of the trials and meta-analyses, particularly the most recent and largest National Institutes of Healthsponsored trial (the Carotid Revascularization Endarterectomy vs Stenting Trial [CREST]), showed that carotid stenting and endarterectomy were associated with similar rates of death and disabling stroke. Within the 30-day periprocedural period, carotid stenting was associated with higher risks of stroke, especially for patients aged >70 years, whereas carotid endarterectomy was associated with a higher risk of myocardial infarction. The slightly higher cost of stenting compared with endarterectomy was within an acceptable range by cost-effectiveness standards. We conclude that carotid artery stenting is an equivalent alternative to carotid endarterectomy when patient age and anatomy, surgical risk, and operator experience are considered in the choice of treatment approach. PMID:22949763

  17. Access-Related Venous Stenoses and Occlusions: Treatment with Percutaneous Transluminal Angioplasty and Dacron-Covered Stents

    SciTech Connect

    Farber, Alexander; Barbey, Mark-Michael; Grunert, Jens-Holger; Gmelin, Ekkechardt

    1999-05-15

    Purpose: To determine the effectiveness of using Dacron-covered stents to treat access-related venous stenoses and occlusions. Methods: Twenty-two Dacron-covered stents were placed in 20 patients: in the basilic or axillary vein (n = 2), cephalic vein (n = 3), subclavian vein (n = 5), and at the venous anastomosis of the polytetrafluoroethylene (PTFE) implant graft (n 10). Results: Initial technical success was 100%. The cumulative primary and secondary patency rates were 57% and 83% at 6 months, 29% and 64% at 12 months, and 29% and 53% at 18 months. A statistically significant difference in the stent patency was revealed by comparing the patients with stents in the subclavian vein and patients with upper arm stents. The secondary patency rates of the upper arm stents were 73% after 6, 12, and 18 months. Conclusions: Percutaneous placement of Dacron-covered stents is a safe and effective procedure for salvage of a dialysis fistula. First results are promising, with a tendency to prolongation of the time interval between reinterventions.

  18. The long-term results of temporary urethral stent placement for the treatment of recurrent bulbar urethral stricture disease

    PubMed Central

    Temeltas, Gokhan; Ucer, Oktay; Yuksel, Mehmet Bilgehan; Gumus, Bilal; Tatli, Volkan; Muezzinoglu, Talha

    2016-01-01

    ABSTRACT Aim: To evaluate the long term outcomes of temporary urethral stent placement for the treatment of recurrent bulbar urethral stricture. Materials and Methods: Twenty-eight patients who underwent temporary polymer coated urethral stent placement due to recurrent bulbar urethral stricture between 2010 and 2014 were enrolled in the study. The long term outcomes of the patients were analyzed. Results: The mean age of the patients was 62.3±6.4 (44–81). The overall clinical success was achieved in 18 (64.2%) of the 28 patients at a median (range) follow-up of 29 (7–46) months. No patient reported discomfort at the stent site. Stone formation was observed at the urethral stent implantation area only in one patient. Stenosis occurred in the distal end of the stents in two patients and took place in bulbar urethra in seven patients after removed the stents. The mean maximum urine flow rates were 6.24±2.81mL/sec and 19.12±4.31mL/sec before and at 3 months after the procedure, respectively. Conclusion: In this study, the success rate of temporary urethral stent placement has remained at 64.2% at a median follow-up of 29 months. Therefore, our outcomes have not achieved desired success rate for the standard treatment of recurrent bulbar urethral stricture. PMID:27256191

  19. Sustained Efficacy and Arterial Drug Retention by a Fast Drug Eluting Cross-Linked Fatty Acid Coronary Stent Coating

    PubMed Central

    Artzi, Natalie; Tzafriri, Abraham R.; Faucher, Keith M.; Moodie, Geoffrey; Albergo, Theresa; Conroy, Suzanne; Corbeil, Scott; Martakos, Paul; Virmani, Renu; Edelman, Elazer R.

    2015-01-01

    The long held assumption that sustained drug elution from stent coatings over weeks to months is imperative for clinical efficacy has limited the choice for stent coating materials. We developed and evaluated an omega-3 fatty acid (O3FA) based stent coating that is 85% absorbed and elutes 97% of its Sirolimus analog (Corolimus) load within 8d of implantation. O3FA coated stents sustained drug levels in porcine coronary arteries similarly to those achieved by slow-eluting durable coated Cypher Select Plus Stents and with significantly lower levels of granuloma formation and luminal stenosis. Computational modeling confirmed that diffusion and binding constants of Corolimus and Sirolimus are identical and explained that the sustained retention of Corolimus was facilitated by binding to high affinity intracellular receptors (FKBP12). First in man outcomes were positive—unlike Cypher stents where late lumen loss drops over 6 month, there was a stable effect without diminution in the presence of O3FA. These results speak to a new paradigm whereby the safety of drug eluting stents can be optimized through the use of resorbable biocompatible coating materials with resorption kinetics that coincide with the dissociation and tissue elimination of receptor-bound drug. PMID:26314990

  20. Mid-Term Results After Endovascular Stent-Grafting of Descending Aortic Aneurysms in High-Risk Patients

    SciTech Connect

    Brandt, Michael Walluscheck, Knut P.; Jahnke, Thomas; Attmann, Tim; Heller, Martin; Cremer, Jochen; Mueller-Huelsbeck, Stefan

    2006-10-15

    Purpose. To analyze our experience with endovascular stent-grafting of descending aortic aneurysms in high-risk patients. Methods. Nineteen patients underwent endovascular stent-graft repair of descending aortic aneurysms using the Talent Stent Graft System (Medtronic). All patients were considered high-risk for open surgical repair due to their age, requirement for emergency surgery, and comorbidities. Computed tomography and/or MR tomography were performed at 3, 6 and 12 months postoperatively and thereafter every 12 months. Results. Secondary technical success was 100%. Thirty-day mortality was 5%. Incidence of postoperative stroke and paraplegia were 5% each. One patient required a second stent-graft due to a type I endoleak during the same hospital stay (primary technical success 95%). All patients have been followed for a median of 20 months. No migration, wire fractures or endoleak appeared during follow-up. Conclusion. Endovascular stent-grafting had a low 30-day mortality and morbidity in high-risk patients. One patient developed an aortoesophageal fistula 40 days after stent implantation. Stent-graft repair is a valuable supplement to surgical therapy in high-risk patients.

  1. Examination of unsteady flow in a mildly curved vessel with stent-like wall protrusions: A tale of two vessels

    NASA Astrophysics Data System (ADS)

    Prince, Chekema; Peterson, Sean D.

    2014-11-01

    New stent designs allow for better conformity to the vessel curvature, maintaining the complex primary and secondary flow patterns present in the native vessel. Despite design improvements, stent induced alterations in local vascular geometry are inevitable and have been associated with stent failure due to in-stent restenosis (ISR). The objective of this study is to elucidate the unsteady flow physics induced by stent implantation, accounting in particular for vessel curvature. The present study focuses on the investigation of unsteady flow through mildly curved vessels with protrusion patterns that emulate current stent designs using computational fluid dynamics (CFD). The modeled geometries include various protrusion frequencies, heights, and widths. Two different arterial velocities waveforms, mimicking the coronary and carotid artery environment, will be considered. A detailed examination of the flow environment induced by the stent presence will be correlated with derived parameters from the flow behavior, such as critical wall shear stress typically associated with ISR development. Specifically, the role of secondary flow in the convective transport of ISR stimuli to the vessel wall will be explored.

  2. Self-expandable metallic stents for palliation of patients with malignant gastric outlet obstruction caused by stomach cancer

    PubMed Central

    Kim, Tae Oh; Kang, Dae Hwan; Kim, Gwang Ha; Heo, Jeong; Song, Geun Am; Cho, Mong; Kim, Dong Heon; Sim, Mun Sup

    2007-01-01

    AIM: To ascertain clinical outcome and complications of self-expandable metal stents for endoscopic palliation of patients with malignant obstruction of the gastrointestinal (GI) tract. METHODS: A retrospective review was performed throughout August 2000 to June 2005 of 53 patients with gastric outlet obstruction caused by stomach cancer. All patients had symptomatic obstruction including nausea, vomiting, and decreased oral intake. All received self-expandable metallic stents. RESULTS: Stent implantation was successful in all 53 (100%) patients. Relief of obstructive symptoms was achieved in 43 (81.1%) patients. No immediate stent-related complications were noted. Seventeen patients had recurrent obstruction (tumor ingrowth in 14 patients, tumor overgrowth in 1 patient, and partial distal stent migration in 2 patients). The mean survival was 145 d. Median stent patency time was 187 d. CONCLUSION: Endoscopic placement of self-expandable metallic stents is a safe and effective treatment for the palliation of patients with inoperable malignant gastric outlet obstruction caused by stomach cancer. PMID:17352023

  3. Clinical safety and efficacy of a next-generation stent-graft device for thoracic endovascular aortic repair.

    PubMed

    Eggebrecht, Holger; Schmermund, Axel; Voigtländer, Thomas

    2013-01-01

    Thoracic endovascular aortic repair has significantly improved the treatment of patients with acute and chronic diseases of the descending thoracic aorta. Retrograde transarterial implantation of a membrane-covered stent graft aims at excluding the aortic pathology at risk for complications (e.g., aneurysm, dissection) from the circulation to prevent expansion and ultimately rupture. Today, several stent grafts from different manufacturers are approved by the respective authorities and thus commercially available. The Medtronic Talent® stent graft used to be one of the initially available devices and has been broadly used to become the world-wide market leader at its time. In 2005, it has been replaced by the second-generation Medtronic Valiant® device, which features several technical improvements. In this article, we evaluate a recent publication investigating the clinical performance of this second-generation stent graft device, and discuss the results in the view of the current literature and developments. PMID:23259442

  4. Knotted stents: Case report and outcome analysis

    PubMed Central

    Lee, Ha Na; Hwang, Hokyeong

    2015-01-01

    A knotted ureteral stent is an extremely rare condition, with fewer than 20 cases reported in the literature; however, it is difficult to treat. We report a case in which a folded Terumo guidewire was successfully used to remove a knotted stent percutaneously without anesthesia. We also review the current literature on predisposing factors and management strategies for knotted ureteral stents. PMID:25964843

  5. 21 CFR 884.3900 - Vaginal stent.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Vaginal stent. 884.3900 Section 884.3900 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES... stent. (a) Identification. A vaginal stent is a device used to enlarge the vagina by stretching, or...

  6. 21 CFR 884.3900 - Vaginal stent.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Vaginal stent. 884.3900 Section 884.3900 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES... stent. (a) Identification. A vaginal stent is a device used to enlarge the vagina by stretching, or...

  7. 21 CFR 884.3900 - Vaginal stent.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Vaginal stent. 884.3900 Section 884.3900 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES... stent. (a) Identification. A vaginal stent is a device used to enlarge the vagina by stretching, or...

  8. 21 CFR 884.3900 - Vaginal stent.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Vaginal stent. 884.3900 Section 884.3900 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES... stent. (a) Identification. A vaginal stent is a device used to enlarge the vagina by stretching, or...

  9. Mechanical properties of different airway stents.

    PubMed

    Ratnovsky, Anat; Regev, Noa; Wald, Shaily; Kramer, Mordechai; Naftali, Sara

    2015-04-01

    Airway stents improve pulmonary function and quality of life in patients suffering from airway obstruction. The aim of this study was to compare main types of stents (silicone, balloon-dilated metal, self-expanding metal, and covered self-expanding metal) in terms of their mechanical properties and the radial forces they exert on the trachea. Mechanical measurements were carried out using a force gauge and specially designed adaptors fabricated in our lab. Numerical simulations were performed for eight different stent geometries, inserted into trachea models. The results show a clear correlation between stent diameter (oversizing) and the levels of stress it exerts on the trachea. Compared with uncovered metal stents, metal stents that are covered with less stiff material exert significantly less stress on the trachea while still maintaining strong contact with it. The use of such stents may reduce formation of mucosa necrosis and fistulas while still preventing stent migration. Silicone stents produce the lowest levels of stress, which may be due to weak contact between the stent and the trachea and can explain their propensity for migration. Unexpectedly, stents made of the same materials exerted different stresses due to differences in their structure. Stenosis significantly increases stress levels in all stents.

  10. 21 CFR 884.3900 - Vaginal stent.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Vaginal stent. 884.3900 Section 884.3900 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES... stent. (a) Identification. A vaginal stent is a device used to enlarge the vagina by stretching, or...

  11. Hemodynamics in coronary arteries with overlapping stents.

    PubMed

    Rikhtegar, Farhad; Wyss, Christophe; Stok, Kathryn S; Poulikakos, Dimos; Müller, Ralph; Kurtcuoglu, Vartan

    2014-01-22

    Coronary artery stenosis is commonly treated by stent placement via percutaneous intervention, at times requiring multiple stents that may overlap. Stent overlap is associated with increased risk of adverse clinical outcome. While changes in local blood flow are suspected to play a role therein, hemodynamics in arteries with overlapping stents remain poorly understood. In this study we analyzed six cases of partially overlapping stents, placed ex vivo in porcine left coronary arteries and compared them to five cases with two non-overlapping stents. The stented vessel geometries were obtained by micro-computed tomography of corrosion casts. Flow and shear stress distribution were calculated using computational fluid dynamics. We observed a significant increase in the relative area exposed to low wall shear stress (WSS<0.5 Pa) in the overlapping stent segments compared both to areas without overlap in the same samples, as well as to non-overlapping stents. We further observed that the configuration of the overlapping stent struts relative to each other influenced the size of the low WSS area: positioning of the struts in the same axial location led to larger areas of low WSS compared to alternating struts. Our results indicate that the overlap geometry is by itself sufficient to cause unfavorable flow conditions that may worsen clinical outcome. While stent overlap cannot always be avoided, improved deployment strategies or stent designs could reduce the low WSS burden.

  12. Antirestenotic Effects of a Novel Polymer-Coated D-24851 Eluting Stent. Experimental Data in a Rabbit Iliac Artery Model

    SciTech Connect

    Lysitsas, Dimitrios N.; Katsouras, Christos S.; Papakostas, John C.; Toumpoulis, Ioannis K.; Angelidis, Charalampos; Bozidis, Petros; Thomas, Christopher G.; Seferiadis, Konstantin; Psychoyios, Nikolaos; Frillingos, Stathis; Pavlidis, Nikolaos; Marinos, Euaggelos; Khaldi, Lubna; Sideris, Dimitris A.; Michalis, Lampros K.

    2007-11-15

    Experimental and clinical data suggest that stents eluting antiproliferative agents can be used for the prevention of in-stent restenosis. Here we investigate in vitro the antiproliferative and apoptotic effect of D-24851 and evaluate the safety and efficacy of D-24851-eluting polymer-coated stents in a rabbit restenosis model (n = 53). Uncoated stents (n = 6), poly (dl-lactide-co-glycolide) (PLGA)-coated stents (n = 7), and PLGA-coated stents loaded with 0.08 {+-} 0.0025 {mu}M (31 {+-} 1 {mu}g; low dose; n = 7), 0.55 {+-} 0.02 {mu}M (216 {+-} 8 {mu}g; high dose; n = 6), and 4.55 {+-} 0.1 {mu}M (1774 {+-} 39 {mu}g; extreme dose; n = 5) of D-24851 were randomly implanted in New Zealand rabbit right iliac arteries and the animals were sacrificed after 28 days for histomorphometric analysis. For the assessment of endothelial regrowth in 90 days, 12 rabbits were subjected to PLGA-coated (n = 3), low-dose (n = 3), high-dose (n = 3), and extreme-dose (n = 3) stent implantation. In vitro studies revealed that D-24851 exerts its growth inhibitory effects via inhibition of proliferation and induction of apoptosis without increasing the expression of heat shock protein-70, a cytoprotective and antiapoptotic protein. Treatment with low-dose D-24851 stents was associated with a significant reduction in neointimal area and percentage stenosis only compared with bare metal stents (38% [P = 0.029] and 35% [P = 0.003] reduction, respectively). Suboptimal healing, however, was observed in all groups of D-24851-loaded stents in 90 days in comparison with PLGA-coated stents. We conclude that low-dose D-24851-eluting polymer-coated stents significantly inhibit neointimal hyperplasia at 28 days through inhibition of proliferation and enhancement of apoptosis. In view of the suboptimal re-endothelialization, longer-term studies are needed in order to establish whether the inhibition of intimal growth is maintained.

  13. Successful Percutaneous Transluminal Angioplasty and Stenting in Acute Mesenteric Ischemia

    SciTech Connect

    Gartenschlaeger, Soeren Bender, Siegfried; Maeurer, Juergen; Schroeder, Ralf J.

    2008-03-15

    Acute mesenteric ischemia (AMI) is a life-threatening emergency. The complications are high by the time of diagnosis in most cases and therefore only few data on primary percutaneous intervention with percutaneous transluminal angioplasty (PTA) and stenting in AMI are available. We present the case of an 84-year-old woman who presented to our emergency department complaining of an acute worsening of pre-existing abdominal periumbilical pain, nausea, vomiting, and diarrhea. She had previously undergone percutaneous transluminal embolectomy for an acute occlusion of the left common femoral artery. Due to suspicion of intestinal infarction, conventional angiography of the aorta and the superior mesenteric artery (SMA) was performed and confirmed a proximal occlusion of the SMA. Percutaneous SMA recanalization with balloon dilation and subsequent stent implantation was carried out successfully. The abdominal symptoms subsided after this procedure. In AMI that is diagnosed early, endovascular stenting should be considered as an alternative treatment to the surgical approach that avoids the need for surgical bowel resection.

  14. Endovascular Treatment of Mycotic Aortic Pseudoaneurysms with Stent-Grafts

    SciTech Connect

    Tiesenhausen, Kurt Hessinger, Michael; Tomka, Maurice; Portugaller, Horst; Swanidze, Shota; Oberwalder, Peter

    2008-05-15

    Mycotic aortic aneurysms remain a therapeutic challenge, especially in patients who are not suitable for open surgery. Endovascular treatment with stent-grafts in this indication is still disputed. Between January 2002 and January 2006, six patients with mycotic aneurysms of the thoracoabdominal or abdominal aorta were admitted to our department. All patients were male, aged 57-83 years (mean, 74.6 years). The mycotic aneurysms were diagnosed on the basis of clinical signs of infection, on CT, and, in four cases, on a positive blood culture. In all patients the mycotic aortic aneurysms were treated endovascularly by stent-graft implantation. Technical and clinical success was achieved in all patients. There was no in-hospital or 30-day mortality. In the follow-up period (range, 2-47 months) four patients died of cancer, cardiac failure, or unknown cause (one case). Two patients are still alive with nearly complete regression of the aneurysms. We conclude that treatment of mycotic aortic aneurysms with stent-grafts may be an alternative in selected patients.

  15. Percutaneous coronary angioscopy and stents

    NASA Astrophysics Data System (ADS)

    Heuser, Richard R.

    1994-05-01

    With the expanding array of therapies available for coronary intervention, the invasive cardiologist has many choices for treating a specific lesion in an individual patient. Certain types of lesions might respond more effectively with stents, particularly the rigid Palmax- Schatz device. Thrombus and dissection immediately following stent placement are associated with early occlusion, and the interventionist must be able to assess their presence pre- and post-stenting. Angiography is deficient in quantifying minimal disease and in defining lesion architecture and composition, as well as the plaque rupture and thrombosis associated with unstable angina. It is also imprecise in detecting dissection and thrombus. Intravascular ultrasound (IVUS) provides high-resolution images that delineate irregularities and other structures inside the lumen and within the vessel wall and surrounding tissues. Like angiography, IVUS has limited specificity for thrombus differentiation. Angioscopy is superior to angiography and IVUS in detecting thrombus and dissection. Angioscopy allows the clinician to assess the appearance of stent struts after deployment and at follow-up. This may aid in reducing acute complications as well as restenosis. Follow-up angioscopy of stents to detect thrombus or exposed struts may guide therapy in a patient who has clinical symptoms of restenosis.

  16. Percutaneous recanalization of totally occluded coarctation of the aorta in children using Brockenbrough needle and covered stents

    PubMed Central

    Tefera, Endale; Leye, Mohamed; Chanie, Yilkal; Raboisson, Marie-Josée; Miró, Joaquim

    2016-01-01

    Percutaneous treatment of totally occluded coarctation of the aorta has been reported predominantly in adults. The success and challenges of this procedure in children is reported in few patients. We report an outcome of percutaneous treatment of three children with completely occluded coarctation of the aorta. The age range was 9-14 years. All the patients had upper limb hypertension. One case had severe left ventricular dysfunction. In all cases, a pediatric Brockenbrough needle and a covered stent were implanted. Recanalization and implantation of a covered stent was successful in all patients. One of these patients developed transient postcoarctectomy syndrome. Percutaneous recanalization of totally occluded coarctation of the aorta using Brockenbrough needle and a covered stent in children is feasible and effective. PMID:27212850

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

    PubMed

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

    2015-01-01

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

  18. Drug loading and elution from a phosphorylcholine polymer-coated coronary stent does not affect long-term stability of the coating in vivo.

    PubMed

    Lewis, Andrew L; Willis, Sean L; Small, Sharon A; Hunt, Stuart R; O'byrne, Vincent; Stratford, Peter W

    2004-01-01

    A drug eluting coronary stent was developed for use in preclinical and clinical trial evaluation. The stent was coated with a phosphorylcholine (PC)-based polymer coating containing the cell migration inhibitor batimastat. A pharmacokinetic study was conducted in a rabbit iliac model using (14)C-radiolabeled version of the drug; this showed the drug release to be first order with 94% of it being released within 28 days. Unloaded and drug-loaded stents were implanted in a porcine coronary artery model; a number were explanted at 5 days and scanning electron microscopy was used to show that the presence of the drug did not affect the rate of stent endothelialization. The remainder of the stents were removed after 6 months and the stents carefully removed from the arterial tissue. Fourier-transform infrared (FT-IR) spectroscopy (both attenuated total reflectance and microscopic imaging) was used to show the presence of the PC coating on control unloaded, drug-loaded and explanted stents, providing evidence that the coating was still present. This was further confirmed by use of atomic force microscopy (AFM) amplitude-phase, distance (a-p,d) curves which generated the characteristic traces of the PC coating. Further AFM depth-profiling techniques found that the thicknesses of the PC coatings on an control unloaded stent was 252+/-19 nm, on an control batimastat-loaded stent 906+/-224 nm and on an explanted stent 405+/-224 nm. The increase in thickness after the drug-loading process was a consequence of drug incorporation in the film, and the return to the unloaded dimensions for the explanted sample indicative of elution of the drug from the coating. The drug delivery PC coating was therefore found to be stable following elution of the drug and after 6 months implantation in vivo. PMID:15472385

  19. Physical and chemical limitations to preparation of beta radioactive stents by direct neutron activation.

    PubMed

    Petelenz, Barbara; Rajchel, Bogusław; Bilski, Paweł; Misiak, Ryszard; Bartyzel, Mirosław; Wilczek, Krzysztof; Alber, Dorothea

    2003-02-01

    Pure beta emitters are the sources of choice for intracoronary irradiations in restenosis prevention. In this work we reconsidered preparation of low activity 32P sources by ion-implantation of stable 31P into highly biocompatible pure titanium stents, followed by neutron activation. Gamma-spectrometrical analysis has shown that during activations with high thermal neutrons flux production of gamma-active long-lived contaminants is much beyond the dosimetrically acceptable limit, mainly due to the competing (n,p) reactions induced by the fast neutrons on isotopes of the bulk stent material, and to a lesser extent due to (n,gamma) reactions on chemical impurities. A potential applicability of this method for obtaining alternative beta radioactive stents<