A small absorbable stent for treatment of anterior glottic web.

Science.gov (United States)

Bhongmakapat, Thongchai; Kantapasuantara, Kanjalak; Praneevatakul, Phurich

2012-03-01

A new one-stage approach for treatment of selected anterior glottic web has been successful. This case report illustrates its simplicity in microlaryngoscopy with complete lysis of the anterior glottic web by CO(2) laser. Then a small neck horizontal incision is made at the level of anterior commissure to gain exposure to thyroid cartilage. Absorbable suture is passed through the midline of thyroid cartilage below and above the anterior commissure. A knot is tied over thyroid ala. The suture acts as a tiny stent to prevent recurrence of the web. Copyright © 2012 The Voice Foundation. Published by Mosby, Inc. All rights reserved.

TCT-584 Nine Month Imaging and Twelve Month Clinical Results from the DESSOLVE II Randomized Trial of the MiStent® SES with Absorbable Polymer

OpenAIRE

Wijns, William; Vrolix, Mathias; Verheye, Stefan; Schoors, Danny; Slagboom, Ton; Gosselink, Marcel; Benit, Edouard; Desmet, Walter; Chowdhary, Saquib; Lansky, Alexandra; Bezerra, Hiram; Fitzgerald, Peter; Kandzari, David; Ormiston, John

2012-01-01

Background : The MiStent SES (Micell Technologies, Durham, NC) is an investigational drug-eluting stent (DES) developed to adress unfavorable late-term outcomes such as stent thrombosis. These events are hypothesized to be associated in part with durable polymers of current DES. The MiStent SES uses a unique combination of components, a crystalline formulation of sirolimus and a fully absorbable polymer on a thinstrut, cobalt chromium stent platform. The polymer coating is eliminated from the...

EFFECT OF STENT ABSORBED c-myc ANTISENSE OLIGODEOXYNUCLEOTIDE ON SMOOTH MUSCLE CELLS APOPTOSIS IN RABBIT CAROTID ARTERY

Institute of Scientific and Technical Information of China (English)

张新霞; 崔长琮; 李江; 崔翰斌; 徐仓宝; 朱参战

2002-01-01

Objective To investigate the effect of gelatin coated Platinium-Iridium stent absorbed c-myc antisense oligodeoxynucleotide (ASODN) on smooth muscle cells apoptosis in a normal rabbit carotid arteries. Methods Gelatin coated Platinium-Iridium stents were implanted in the right carotid arteries of 32 rabbits under vision. Animals were randomly divided into control group and treated group receiving c-myc ASODN (n=16, respectively). On 7, 14, 30 and 90 days following the stenting procedure ,morphometry for caculation of neointimal area and mean neointimal thickness were performed.The expression of c-myc protein was detected by immunohistochemical method. Apoptotic smooth muscle cells was detected by terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL). Results At 7 and 14 days after stenting,there were no detectable apoptotic cells in both groups. The apoptotic cells occurred in the neointima 30 and 90 days after stenting, and the number of apoptotic cells at 30 days were less [4.50±1.29 vs 25.75±1.89 (number/0.1mm2)] than that at 90 days [13.50±1.91 vs 41.50±6.46 (number/0.1mm2)]. Meanwhile c-myc ASODN induced more apoptotic cells than the control group(P<0.0001). c-myc protein expression was weak positive or negative in treated group and positive in control group.Conclusion c-myc ASODN can induce smooth muscle cells apoptosis after stenting in normal rabbit carotid arteries,and it can be used to prevent in-stent restenosis.

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

Science.gov (United States)

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. Copyright © 2012 Wiley Periodicals, Inc.

The Impact of Post-Procedural Asymmetry, Expansion, and Eccentricity of Bioresorbable Everolimus-Eluting Scaffold and Metallic Everolimus-Eluting Stent on Clinical Outcomes in the ABSORB II Trial.

Science.gov (United States)

Suwannasom, Pannipa; Sotomi, Yohei; Ishibashi, Yuki; Cavalcante, Rafael; Albuquerque, Felipe N; Macaya, Carlos; Ormiston, John A; Hill, Jonathan; Lang, Irene M; Egred, Mohaned; Fajadet, Jean; Lesiak, Maciej; Tijssen, Jan G; Wykrzykowska, Joanna J; de Winter, Robbert J; Chevalier, Bernard; Serruys, Patrick W; Onuma, Yoshinobu

2016-06-27

The study sought to investigate the relationship between post-procedural asymmetry, expansion, and eccentricity indices of metallic everolimus-eluting stent (EES) and bioresorbable vascular scaffold (BVS) and their respective impact on clinical events at 1-year follow-up. Mechanical properties of a fully BVS are inherently different from those of permanent metallic stent. The ABSORB II (A bioresorbable everolimus-eluting scaffold versus a metallic everolimus-eluting stent for ischaemic heart disease caused by de-novo native coronary artery lesions) trial compared the BVS and metallic EES in the treatment of a de novo coronary artery stenosis. Protocol-mandated intravascular ultrasound imaging was performed pre- and post-procedure in 470 patients (162 metallic EES and 308 BVS). Asymmetry index (AI) was calculated per lesion as: (1 - minimum scaffold/stent diameter/maximum scaffold/stent diameter). Expansion index and optimal scaffold/stent expansion followed the definition of the MUSIC (Multicenter Ultrasound Stenting in Coronaries) study. Eccentricity index (EI) was calculated as the ratio of minimum and maximum scaffold/stent diameter per cross section. The incidence of device-oriented composite endpoint (DoCE) was collected. Post-procedure, the metallic EES group was more symmetric and concentric than the BVS group. Only 8.0% of the BVS arm and 20.0% of the metallic EES arm achieved optimal scaffold/stent expansion (p 0.30 is an independent predictor of DoCE (hazard ratio: 3.43; 95% confidence interval: 1.08 to 10.92; p = 0.037). BVS implantation is more frequently associated with post-procedural asymmetric and eccentric morphology compared to metallic EES. Post-procedural devices asymmetry were independently associated with DoCE following percutaneous coronary intervention. However, this approach should be viewed as hypothesis generating due to low event rates. (ABSORB II Randomized Controlled Trial [ABSORB II]; NCT01425281). Copyright © 2016 American

Serial assessment by optical coherence tomography of early and late vascular responses after implantation of an absorbable-coating Sirolimus-Eluting stent (from the first-in-human DESSOLVE I trial).

Science.gov (United States)

Attizzani, Guilherme F; Bezerra, Hiram G; Ormiston, John; Wang, Wei; Donohoe, Dennis; Wijns, William; Costa, Marco A

2013-11-15

The initial enthusiasm caused by the potent antirestenotic effect of early generation drug-eluting stents was recently plagued by concerns regarding their safety profile. Investigators worldwide were stimulated, therefore, to seek for improvement in drug-eluting stent technology, such as eliminating their permanent polymer blamed for vascular inflammation and delayed healing. Optical coherence tomography (OCT) assessments of stent-vessel interactions are used as a surrogate for vessel healing after DES implantation. Herewith, we report serial OCT assessments of vascular reactions to the implantation of a novel absorbable polymer sirolimus-eluting stent (MiStent). In total, 30 patients were included. At 4-, 6-, and 8-month follow-up, different groups of 10 patients underwent OCT imaging, whereas all the patients had OCT assessments scheduled at 18-month follow-up. A total of 13,569 stent struts were analyzed. Low rates of uncovered (14.34 ± 15.35%, 6.62 ± 10.93%, 3.51 ± 2.87%, and 0.84 ± 1.15%, respectively, p stent struts coupled with thin and increasingly homogenous neointimal proliferation were demonstrated. Neointimal area increased from 4- to 8-month follow-up (0.46 ± 0.29 and 1.12 ± 0.73 mm(2), respectively, p stent struts (8.8%, 3.1%, 0.3%, and 0%, respectively, p absorbable polymer sirolimus-eluting stent-vessel interactions up to 18-month follow-up. Copyright © 2013 Elsevier Inc. All rights reserved.

Absorbable stent: focus on clinical applications and benefits

OpenAIRE

Gonzalo, Nieves; Macaya, Carlos

2012-01-01

Nieves Gonzalo, Carlos MacayaInterventional Cardiology, Cardiovascular Institute. Hospital Clinico San Carlos, Instituto de Investigación Sanitaria del Hospital Clinico San Carlos, Madrid, SpainAbstract: Coronary stents have improved very significantly the immediate and long-term results of percutaneous coronary interventions. However, once the vessel has healed, the scaffolding function of the stent is no longer needed, and the presence of a permanent metallic prosthesis poses imp...

Flexibility and trackability of laser cut coronary stent systems.

Science.gov (United States)

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.

A sirolimus-eluting bioabsorbable polymer-coated stent (MiStent) versus an everolimus-eluting durable polymer stent (Xience) after percutaneous coronary intervention (DESSOLVE III): a randomised, single-blind, multicentre, non-inferiority, phase 3 trial

NARCIS (Netherlands)

de Winter, Robbert J.; Katagiri, Yuki; Asano, Taku; Milewski, Krzysztof P.; Lurz, Philipp; Buszman, Pawel; Jessurun, Gillian A. J.; Koch, Karel T.; Troquay, Roland P. T.; Hamer, Bas J. B.; Ophuis, Ton Oude; Wöhrle, Jochen; Wyderka, Rafał; Cayla, Guillaume; Hofma, Sjoerd H.; Levesque, Sébastien; Żurakowski, Aleksander; Fischer, Dieter; Kośmider, Maciej; Goube, Pascal; Arkenbout, E. Karin; Noutsias, Michel; Ferrari, Markus W.; Onuma, Yoshinobu; Wijns, William; Serruys, Patrick W.

2018-01-01

Background MiStent is a drug-eluting stent with a fully absorbable polymer coating containing and embedding a microcrystalline form of sirolimus into the vessel wall. It was developed to overcome the limitation of current durable polymer drug-eluting stents eluting amorphous sirolimus. The clinical

A method to determine the kink resistance of stents and stent delivery systems according to international standards

Directory of Open Access Journals (Sweden)

Brandt-Wunderlich Christoph

2016-09-01

Full Text Available The kink behavior of vascular stents is of particular interest for clinicians, stent manufacturers and regulatory as a kinked stent generates a lumen loss in the stented vessel and can lead to in-stent restenosis. In this study methods to determine the kink resistance of stents and stent delivery systems according to the ISO 25539-2 and FDA guidance no. 1545 were presented. The methods are applicable for balloon expandable stents as well as for self-expanding stents and determine the lumen loss and residual diameter change dependent on the specific bending radius.

Shrinking the Supply Chain for Implantable Coronary Stent Devices.

Science.gov (United States)

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.

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

Science.gov (United States)

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

2015-12-01

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

Simulative study on dose distribution of 103Pd stent in blood-vessel

International Nuclear Information System (INIS)

Yuan Shuyu; Dai Guangfu; Xu Zhiyong; Sun Fuyin; Xu Shuhe; Ma Fengwu

2003-01-01

Objective: To evaluate the dose distribution of 103 Pd stent in the blood-vessel. Methods: Simulative study on dose distribution of endovascular 103 Pd stent was conducted with thermoluminescence dosimeter. The vessel wall was substituted by muscle equivalent material in this simulative study. Results: When radioactivity of the study 103 Pd stent was 9.8 MBq the absorbed dose from the stent surface by muscle equivalent material was 9.8 Gy at 17 d (the half-life period of 103 Pd). The radioactivity of 103 Pd stent surface rapidly attenuated over the radial distance. 80% of the radioactivity at the area that was radially 0.4 mm apart from the stent surface was absorbed by the simulative blood-vessel wall. Conclusion: Endovascular 103 Pd stent does not exert significant injury on the surrounding organs or tissues

[Coronary stents: 30 years of medical progress].

Science.gov (United States)

Silvain, Johanne; Cayla, Guillaume; Collet, Jean-Philippe; Fargeot, Catherine; Montalescot, Gilles

2014-03-01

The history of interventional cardiology has been marked by several technologic revolutions since the late 1970s. The first key step was the use of inflatable balloon angioplasty as an alternative to CABG surgery for coronary revascularization, followed by intracoronary delivery of bare metal stent (BMS) and drug eluting stents (DES) to drastically reduce intracoronary restenosis observed with BMS. Improved stents platforms and polymers (absorbable or biocompatible) led to a dramatic reduction in the rate of late stent thrombosis. Self-expanding stents are now available to improve stent a position especially in acute myocardial infarction. The emergence of new fully bioabsorbable stents that can be combined with antiproliferative drugs is the ongoing revolution. A new generation of stents is continuously improving and likely to become the ideal stent for coronary revascularization in the near future. © 2014 médecine/sciences – Inserm.

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

Science.gov (United States)

Di Dedda, Giovanni; Mirabile, Cristian

2017-01-01

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

Computational micromechanics of bioabsorbable magnesium stents.

Science.gov (United States)

Grogan, J A; Leen, S B; McHugh, P E

2014-06-01

Magnesium alloys are a promising candidate material for an emerging generation of absorbable metal stents. Due to its hexagonal-close-packed lattice structure and tendency to undergo twinning, the deformation behaviour of magnesium is quite different to that of conventional stent materials, such as stainless steel 316L and cobalt chromium L605. In particular, magnesium exhibits asymmetric plastic behaviour (i.e. different yield behaviours in tension and compression) and has lower ductility than these conventional alloys. In the on-going development of absorbable metal stents it is important to assess how the unique behaviour of magnesium affects device performance. The mechanical behaviour of magnesium stent struts is investigated in this study using computational micromechanics, based on finite element analysis and crystal plasticity theory. The plastic deformation in tension and bending of textured and non-textured magnesium stent struts with different numbers of grains through the strut dimension is investigated. It is predicted that, unlike 316L and L605, the failure risk and load bearing capacity of magnesium stent struts during expansion is not strongly affected by the number of grains across the strut dimensions; however texturing, which may be introduced and controlled in the manufacturing process, is predicted to have a significant influence on these measures of strut performance. Copyright © 2014 Elsevier Ltd. All rights reserved.

Preliminary study of performance of peripheral absorbable magnesium alloy stent%外周动脉可吸收镁合金支架性能初探

Institute of Scientific and Technical Information of China (English)

肖耀文; 陈忠; 杨耀国; 寇镭; 郑丰; 张炳春; 白树功; 郑焕勤; 刘博文

2016-01-01

Objective To investigate the performance and safety of domestic peripherally absorbable magnesium alloy stent.Methods Sixteen absorbable magnesium alloy stents were implanted in the bilateral iliac-femoral arteries of 8 Chinese Agricultural University minipigs selected randomly with computer.The mean weight was (21.19± 1.93)kg.One pig was randomly selected by computer on 30th,45th,60th,75th,90th,105th,120th and 135th days after stent implantation and both stents were removed.The biochemical,imaging and histopathology index of the pig before and after stent placement were analyzed,t test was used to compare data collected before and after stenting.Results The biochemical index changes showed no statistical significance after stent implantation,the DSA indicated that vessel diameter was (4.39± 0.26) mm before stent implantation and (3.85±0.71)mm on the 30th to 135th day afterimplatation (t=3.041,P=0.008),the balance of vessel diameter before and after stenting ranged from 0 to 2.29 mm,with minimun on 30th day,and maximum on 90th day;HE and verhoeffvangieson showed significant stenosis of the arteries occurred on 60'h,90th and 120th day.From the 30th day to 135th day after stenting,the average diameter of residual lumen was (1.38±0.18) mm,the average area of residual lumen was (1.51±0.41) mm2,the average area of internal elastic lamina was (1.91t0.22) mm2,the average area of external elastic lamina was (4.79± 0.79) mm2,the average thickness of endothelium was (0.11 ±0.06) mm,the average area of new intima was (0.40±0.29) mm2,the average narrow area percentage was (21.96± 16.48)％.The stent absorbed gradually,and not completely absorbed until 135th day after stenting.Endometrial cells completely covered stent surface,and the stent did not break or collapse at all.Conclusions The peripherally absorbable magnesium alloy stents is safe and effective in animal experiment.Application of this stent in human should be investigated with further studies.%目的 �

1-year clinical outcomes of diabetic patients treated with everolimus-eluting bioresorbable vascular scaffolds: a pooled analysis of the ABSORB and the SPIRIT trials.

Science.gov (United States)

Muramatsu, Takashi; Onuma, Yoshinobu; van Geuns, Robert-Jan; Chevalier, Bernard; Patel, Tejas M; Seth, Ashok; Diletti, Roberto; García-García, Hector M; Dorange, Cécile C; Veldhof, Susan; Cheong, Wai-Fung; Ozaki, Yukio; Whitbourn, Robert; Bartorelli, Antonio; Stone, Gregg W; Abizaid, Alexandre; Serruys, Patrick W

2014-05-01

The aim of this study was to evaluate 1-year clinical outcomes of diabetic patients treated with the Absorb bioresorbable vascular scaffold (BVS). Clinical outcomes of diabetic patients after BVS implantation have been unreported. This study included 101 patients in the ABSORB Cohort B trial and the first consecutive 450 patients with 1 year of follow-up in the ABSORB EXTEND trial. A total of 136 diabetic patients were compared with 415 nondiabetic patients. In addition, 882 diabetic patients treated with everolimus-eluting metal stents (EES) in pooled data from the SPIRIT trials (SPIRIT FIRST [Clinical Trial of the Abbott Vascular XIENCE V Everolimus Eluting Coronary Stent System], SPIRIT II [A Clinical Evaluation of the XIENCE V Everolimus Eluting Coronary Stent System], SPIRIT III [Clinical Trial of the XIENCE V Everolimus Eluting Coronary Stent System (EECSS)], SPIRIT IV Clinical Trial [Clinical Evaluation of the XIENCE V Everolimus Eluting Coronary Stent System]) were used for the comparison by applying propensity score matching. The primary endpoint was a device-oriented composite endpoint (DoCE), including cardiac death, target vessel myocardial infarction, and target lesion revascularization at 1-year follow-up. The cumulative incidence of DoCE did not differ between diabetic and nondiabetic patients treated with the BVS (3.7% vs. 5.1%, p = 0.64). Diabetic patients treated with the BVS had a similar incidence of the DoCE compared with diabetic patients treated with EES in the matched study group (3.9% for the BVS vs. 6.4% for EES, p = 0.38). There were no differences in the incidence of definite or probable scaffold/stent thrombosis (0.7% for both diabetic and nondiabetic patients with the BVS; 1.0% for diabetic patients with the BVS vs. 1.7% for diabetic patients with EES in the matched study group). In the present analyses, diabetic patients treated with the BVS showed similar rates of DoCEs compared with nondiabetic patients treated with the BVS and

Everolimus-eluting bioresorbable stent vs. durable polymer everolimus-eluting metallic stent in patients with ST-segment elevation myocardial infarction

DEFF Research Database (Denmark)

Sabaté, Manel; Windecker, Stephan; Iñiguez, Andres

2015-01-01

AIMS: Patients with ST-segment elevation myocardial infarction (STEMI) feature thrombus-rich lesions with large necrotic core, which are usually associated with delayed arterial healing and impaired stent-related outcomes. The use of bioresorbable vascular scaffolds (Absorb) has the potential...... to overcome these limitations owing to restoration of native vessel lumen and physiology at long term. The purpose of this randomized trial was to compare the arterial healing response at short term, as a surrogate for safety and efficacy, between the Absorb and the metallic everolimus-eluting stent (EES...... was the 6-month optical frequency domain imaging healing score (HS) based on the presence of uncovered and/or malapposed stent struts and intraluminal filling defects. Main secondary endpoint included the device-oriented composite endpoint (DOCE) according to the Academic Research Consortium definition...

[Developments in percutaneous coronary intervention and coronary stents].

Science.gov (United States)

Simsek, C; Daemen, J; Zijlstra, F

2014-01-01

In The Netherlands, more than 30.000 patients undergo a percutaneous coronary intervention every year, during which a coronary stent implantation will be performed in 90% of the cases. It is estimated that more than 5 million coronary stent implantations will be performed worldwide this year. While these numbers are impressive, however, coronary stents still have as a limitation the possibility of stent thrombosis. This has been and is an important stimulus for the development of both coronary stents, from a bare metal stent via a drug eluting stent to the present-day development of bio-absorbable stents, and anti-platelet drugs,from acenocoumarol to thieropyridines. The possibility of shortening the period of use of this powerful medication by developing new kinds of non-thrombogenic stents would, for example, make it possible to achieve significant reductions in subsequent bleeding during (dental) procedures.

Bile Duct Anastomosis Supplied With Biodegradable Stent in Liver Transplantation: The Initial Experience.

Science.gov (United States)

Janousek, L; Maly, S; Oliverius, M; Kocik, M; Kucera, M; Fronek, J

2016-12-01

The most common biliary complications after orthotopic liver transplantation are bile leaks, anastomotic and intrahepatic strictures, stones, and ampullary dysfunction. These complications can occur in up to 10% to 30% of liver transplant recipients. Leaks occur early in the posttransplant period; the stricture formation typically graduates over time. Ten patients underwent transplantation in our preliminary study: 5 were randomized to the group with stent placement and 5 to the control group. We investigated the role of an absorbable biliary stent with the goal of proving patency of duct-to-duct biliary anastomosis. The stents are made of machine-knitted polydioxanone monofilaments. Our initial results show that duct-to-duct biliary reconstruction using an absorbable internal stent had good patency in all 5 patients. There were no signs of biliary leakage accompanying the anastomoses in any of the cases, and there was no stone formation observed after liver transplantation. The biliary stent was completely absorbed, with no adverse effects. Based on our initial experience and data, we concluded that biodegradable stents can be successfully and safely used in clinical practice. Further large prospective randomized studies are needed to estimate the efficacy of the bioabsorbable stents. Copyright © 2016 Elsevier Inc. All rights reserved.

High-resolution 3D X-ray imaging of intracranial nitinol stents

International Nuclear Information System (INIS)

Snoeren, Rudolph M.; With, Peter H.N. de; Soederman, Michael; Kroon, Johannes N.; Roijers, Ruben B.; Babic, Drazenko

2012-01-01

To assess an optimized 3D imaging protocol for intracranial nitinol stents in 3D C-arm flat detector imaging. For this purpose, an image quality simulation and an in vitro study was carried out. Nitinol stents of various brands were placed inside an anthropomorphic head phantom, using iodine contrast. Experiments with objects were preceded by image quality and dose simulations. We varied X-ray imaging parameters in a commercially interventional X-ray system to set 3D image quality in the contrast-noise-sharpness space. Beam quality was varied to evaluate contrast of the stents while keeping absorbed dose below recommended values. Two detector formats were used, paired with an appropriate pixel size and X-ray focus size. Zoomed reconstructions were carried out and snapshot images acquired. High contrast spatial resolution was assessed with a CT phantom. We found an optimal protocol for imaging intracranial nitinol stents. Contrast resolution was optimized for nickel-titanium-containing stents. A high spatial resolution larger than 2.1 lp/mm allows struts to be visualized. We obtained images of stents of various brands and a representative set of images is shown. Independent of the make, struts can be imaged with virtually continuous strokes. Measured absorbed doses are shown to be lower than 50 mGy Computed Tomography Dose Index (CTDI). By balancing the modulation transfer of the imaging components and tuning the high-contrast imaging capabilities, we have shown that thin nitinol stent wires can be reconstructed with high contrast-to-noise ratio and good detail, while keeping radiation doses within recommended values. Experimental results compare well with imaging simulations. (orig.)

Biodegradable Metals for Cardiovascular Stents: from Clinical Concerns to Recent Zn-Alloys.

Science.gov (United States)

Bowen, Patrick K; Shearier, Emily R; Zhao, Shan; Guillory, Roger J; Zhao, Feng; Goldman, Jeremy; Drelich, Jaroslaw W

2016-05-01

Metallic stents are used to promote revascularization and maintain patency of plaqued or damaged arteries following balloon angioplasty. To mitigate the long-term side effects associated with corrosion-resistant stents (i.e., chronic inflammation and late stage thrombosis), a new generation of so-called "bioabsorbable" stents is currently being developed. The bioabsorbable coronary stents will corrode and be absorbed by the artery after completing their task as vascular scaffolding. Research spanning the last two decades has focused on biodegradable polymeric, iron-based, and magnesium-based stent materials. The inherent mechanical and surface properties of metals make them more attractive stent material candidates than their polymeric counterparts. A third class of metallic bioabsorbable materials that are based on zinc has been introduced in the last few years. This new zinc-based class of materials demonstrates the potential for an absorbable metallic stent with the mechanical and biodegradation characteristics required for optimal stent performance. This review compares bioabsorbable materials and summarizes progress towards bioabsorbable stents. It emphasizes the current understanding of physiological and biological benefits of zinc and its biocompatibility. Finally, the review provides an outlook on challenges in designing zinc-based stents of optimal mechanical properties and biodegradation rate. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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

Science.gov (United States)

Alexy, Ryan D.; Levi, Daniel S.

2013-01-01

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

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

Directory of Open Access Journals (Sweden)

Ryan D. Alexy

2013-01-01

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

Revisiting the tethered ureteral stents in children: a novel modification.

Science.gov (United States)

Kajbafzadeh, Abdol-Mohammad; Nabavizadeh, Behnam; Keihani, Sorena; Hosseini Sharifi, Seyed Hossein

2015-06-01

To propose a simple noninvasive method for ureteral stent retrieval using an extraction string sutured to the skin in children. A retrospective chart review was performed to gather relevant data from December 2005 to February 2013. After the surgeries, if indicated, a tethered double-J stent was placed in the ureter. A 5-0 non-absorbable Prolene stitch was used as an extraction string passing through the urethra and was sutured to subcoronal skin in boys or inner surface of labia majora in girls. For stent removal, a small amount of 2 % lidocaine jelly was pushed into the urethra 5 min before the procedure. The string was then pulled by continuous and gentle force until the entire stent was out. The suture was then cut to release the stent. No sedation or anesthesia was needed. A total of 378 double-J stents with extraction strings were inserted for a total of 325 patients (61.2 % male). Of the 53 patients with bilateral ureteral stents, one male patient (1.88 %) experienced early stent protrusion from urethral meatus. Two of 272 patients (0.73 %) with unilateral ureteral stent (one male and one female) encountered the same problem. All other stents were extracted successfully using the extraction string without any complications. No upward stent migration or suture site reaction was encountered. This method is a safe, easy-to-use, feasible and noninvasive alternative for cystoscopic stent removal with high success rate and minimal complications. This can lead to considerable saving in time and costs for patients, families and healthcare system.

Effects of fatigue on the chemical and mechanical degradation of model stent sub-units.

Science.gov (United States)

Dreher, Maureen L; Nagaraja, Srinidhi; Batchelor, Benjamin

2016-06-01

Understanding the fatigue and durability performance of implantable cardiovascular stents is critical for assessing their performance. When the stent is manufactured from an absorbable material, however, this durability assessment is complicated by the transient nature of the device. Methodologies for evaluating the fatigue performance of absorbable stents while accurately simulating the degradation are limited and little is known about the interaction between fatigue and degradation. In this study, we investigated the fatigue behavior and effect of fatigue on the degradation rate for a model absorbable cardiovascular stent. Custom v-shaped stent sub-units manufactured from poly(L-lactide), i.e., PLLA, were subjected to a simultaneous fatigue and degradation study with cycle counts representative of one year of expected in vivo use. Fatigue loading was carried out such that the polymer degraded at a rate that was aligned with a modest degree of fatigue acceleration. Control, un-loaded specimens were also degraded under static immersion conditions representative of simulated degradation without fatigue. The study identified that fatigue loading during degradation significantly increased specimen stiffness and lowered the force at break. Fatigue loading also significantly increased the degree of molecular weight decline highlighting an interaction between mechanical loading and chemical degradation. This study demonstrates that fatigue loading during degradation can affect both the mechanical properties and the chemical degradation rate. The results are important for defining appropriate in vitro degradation conditions for absorbable stent preclinical evaluation. Published by Elsevier Ltd.

Differential impact of five coronary devices on plaque size: insights from the ABSORB and SPIRIT trials.

Science.gov (United States)

García-García, Héctor M; Serruys, Patrick W; Campos, Carlos M; Onuma, Yoshinobu

2014-08-20

Coronary plaque size modification, by either local (device) or systemic treatments, has been the target for many years. From ABSORB Cohort A (Absorb BVS 1.0), ABSORB Cohort B (Absorb BVS 1.1), SPIRIT FIRST (Multi-Link Vision vs. Xience V) & SPIRIT II (Xience V vs. Taxus), we calculated the total plaque area (vessel minus lumen area - thus it comprises both compartments - the plaque behind struts and the neointima.) changes by IVUS. A total of 313 patients were included. Comparison-at-6-month follow-up: All devices induced an increase in the total plaque area. The largest increase occurred with Vision and Taxus stents as compared to other devices [Absorb BVS (1.0 and 1.1) and Xience V], (p=0.0002). Comparison-at-2-year follow-up: Absorb BVS 1.1 had a larger increase from post procedure in total plaque compared to Absorb BVS 1.0, Xience V and Taxus (p=0.0499). However, in Absorb BVS 1.1 total plaque showed a reduction of 2.2% from 1 to 3 years. Specifically, the total plaque in the sequential cohorts of Absorb BVS 1.1 increased 16.2% from baseline to 2 years (Cohort B1) while at 3 years this increase is only 5% compared to baseline (Cohort B2). Local devices affect coronary plaque size differently and it depends on the platform (metallic vs. polymeric) and on whether it is a bare - or drug eluting stent. Coronary scaffolds appear to be a promising alternative to metallic stents since they allow plaque regression at long-term follow-up. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Genous endothelial progenitor cell-capturing stent system: a novel stent technology

NARCIS (Netherlands)

Klomp, Margo; Beijk, Marcel A. M.; de Winter, Robbert J.

2009-01-01

Drug-eluting stents have been demonstrated to significantly reduce clinical and angiographic restenosis in patients with coronary artery disease compared with bare-metal stents. Intuitively, however, a prohealing approach for the prevention of in-stent restenosis by promoting accelerated

Overlapping bio-absorbable scaffolds: Aim for D2D technique?

Science.gov (United States)

Khan, Asaad A; Dangas, George D

2018-06-01

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

新型血管内可吸收镁合金支架的实验研究%Experimental novel absorbable magnesium alloy stent

Institute of Scientific and Technical Information of China (English)

杨水祥; 雷力成; 王丽丽; 昌红; 王尔德; 吴坤; 崔福斋; 杨静罄; 朱锦文

2012-01-01

Objective To assess the biocompatibility,efficacy and safty of a self designed and mani-factured novel absorbable magnesium alloy stent. Methods An absorbable magnesium alloy stent was implanted into the coronary and femoral artery of 35 hybrid dogs,respectively. The implanted stents were observed by coronary arteriography and femoral arteriography, respectively. The isolated blood vessels in the stent segment were observed by histopathology and their computer images were analyzed on days 1,3,5,7,14,21 and 28 after operation,and five dogs in each group. Results Fifty one stents were successfully implanted into the coronary and femoral artery of 35 dogs. Coronary and femoral arteriography showed that the stenting vessels were patent with no stenosis and thrombosis. Histopathology showed no intimal hyperplasia but residual stent on days 1,3 and 5 after operation. The stent was completely degraded on day 7 after operation. The intimal hyperplasia was observed on day 14 after operation and became significant on days 21 ?28. No significant inflammatory reaction and thrombosis were found at different time points after operation. The intimal hyperplasia area was 0. 04 + 0. 03 mm2,0. 10 + 0. 03 mm' and 0. 15?. 04 mm2 .respectively on days 14, 21 and 28 after operation,accounting for 1.84% + 1. 18%,3. 72%?. 12% and 6. 29%?. 36% , respectively(P<0. 05). Conclusion Absorbable magnesium alloy stent is easy to manipulate with a good biocompatibility,efficacy and safety,and is thus of a vast prospect in its clinical application.%目的 评估自行设计制作的新型血管内可吸收镁合金支架的生物相容性、有效性和安全性.方法 杂种犬35只,每只犬均于冠状动脉和股动脉置入可吸收镁合金支架1枚,分别于术后1、3、5d和1、2、3、4周,每个时间点5只犬,复查冠状动脉和股动脉,血管造影后取材,分离支架段血管行组织病理观察及�

Ligament regeneration using an absorbable stent-shaped poly-L-lactic acid scaffold in a rabbit model.

Science.gov (United States)

Nishimoto, Hanako; Kokubu, Takeshi; Inui, Atsuyuki; Mifune, Yutaka; Nishida, Kotaro; Fujioka, Hiroyuki; Yokota, Kumiko; Hiwa, Chiaki; Kurosaka, Masahiro

2012-11-01

Ligaments are frequently damaged in sports activities and trauma, and severe ligament injury can lead to joint instability and osteoarthritis. In this study, we aimed to regenerate the medial collateral ligament (MCL) using an absorbable stent-shaped poly-L-lactic acid (PLLA) scaffold in a rabbit model to examine the biocompatibility and mechanical properties. Twenty-three Japanese white rabbits were used in this study. MCL defects were surgically created in the knee joints and then reconstructed using stent-shaped PLLA scaffolds. As controls, flexor digitorum longus (FDL) tendons were implanted into the contralateral knees. Seven rabbits were sacrificed at three time points, conducted four, eight and 16 weeks after the operation. The regenerated tissues were histologically evaluated using fibre alignment scoring, morphology of fibroblast scoring and immunohistochemical analysis of types I and III collagen. The regenerated tissues were also biomechanically evaluated by measuring the ultimate failure load and stiffness. At four weeks post-operation, spindle-shaped cells were observed on the inside of the scaffolds. At eight weeks, maturation of the regenerated tissues and collagen fibre alignment parallel to the ligaments was observed. At 16 weeks, the fibre alignment had become denser. The fibre alignment and morphology of fibroblast scores significantly increased in a time-dependent manner. Expression of type I collagen was more strongly observed in the scaffold group at eight and 16 weeks post-operation than at four weeks. Type III collagen was also observed at four, eight and 16 weeks post-operation. A thin layer of fibrocartilage was observed at the ligament-bone junction at eight and 16 weeks. The ultimate failure load of the scaffold group was 46.7 ± 20.7 N, 66.5 ± 11.0 N and 74.3 ± 11.5 N at four, eight and 16 weeks post-operation, respectively. There was no statistical difference between the normal MCL and the scaffold group at 16 weeks post

Angiographic CT: in vitro comparison of different carotid artery stents-does stent orientation matter?

Science.gov (United States)

Lettau, Michael; Bendszus, Martin; Hähnel, Stefan

2013-06-01

Our aim was to evaluate the in vitro visualization of different carotid artery stents on angiographic CT (ACT). Of particular interest was the influence of stent orientation to the angiography system by measurement of artificial lumen narrowing (ALN) caused by the stent material within the stented vessel segment to determine whether ACT can be used to detect restenosis within the stent. ACT appearances of 17 carotid artery stents of different designs and sizes (4.0 to 11.0 mm) were investigated in vitro. Stents were placed in different orientations to the angiography system. Standard algorithm image reconstruction and stent-optimized algorithm image reconstruction was performed. For each stent, ALN was calculated. With standard algorithm image reconstruction, ALN ranged from 19.0 to 43.6 %. With stent-optimized algorithm image reconstruction, ALN was significantly lower and ranged from 8.2 to 18.7 %. Stent struts could be visualized in all stents. Differences in ALN between the different stent orientations to the angiography system were not significant. ACT evaluation of vessel patency after stent placement is possible but is impaired by ALN. Stent orientation of the stents to the angiography system did not significantly influence ALN. Stent-optimized algorithm image reconstruction decreases ALN but further research is required to define the visibility of in-stent stenosis depending on image reconstruction.

A rapid-exchange monorail stent system for salvage of failing femoropopliteal bypass grafts.

Science.gov (United States)

Jahnke, Thomas; Brossmann, Joachim; Walluscheck, Knut; Heller, Martin; Müller-Hülsbeck, Stefan

2003-08-01

To analyze the safety and effectiveness of a new monorail stent system for the treatment of failing femoropopliteal bypass grafts. Acute distal occlusions or stenoses of femoropopliteal bypass grafts were treated with balloon-expandable stents (13 or 18-mm diameter) pre-mounted on a monorail balloon catheter system. The delivery system was assessed subjectively for (1). compatibility with the sheath, (2). lesion crossing potential, (3). radiopacity, (4). flexibility of the catheter, (5). adequacy of stent expansion, and (5). balloon refolding. In 8 failing bypass grafts with distal lesions, the delivery system successfully deployed the stent at the desired location. Sheath compatibility, catheter flexibility, lesion crossing, and stent expansion were rated "excellent" by all examiners for the 18-mm device. Radiopacity of the mounted stent was graded "good" before and during positioning, but only "sufficient" following expansion. For this type of lesion, the investigators rated the overall performance of the device superior to conventional "over-the-wire" systems. The monorail balloon-expandable stent delivery system provides rapid introduction of the device over the guidewire, and its low profile facilitates the use of small sheaths to minimize access-site complications.

Bioabsorbable polymer-coated sirolimus-eluting stent implantation preserves coronary vasomotion: A DESSOLVE II trial sub-study.

Science.gov (United States)

Rusinaru, Dan; Vrolix, Mathias; Verheye, Stefan; Chowdhary, Saqib; Schoors, Danny; Di Mario, Carlo; Desmet, Walter; Donohoe, Dennis J; Ormiston, John A; Knape, Charlene; Bezerra, Hiram; Lansky, Alexandra; Wijns, William

2015-12-01

We studied coronary vasomotion in patients treated with the Mistent(®) absorbable polymer sirolimus-eluting stent (APSES) and in patients implanted with the Endeavor(®) zotarolimus-eluting stent (ZES). First generation (1st-gen) drug-eluting stents (DES) induce persistent vasomotor dysfunction in the treated coronary artery. It is unknown whether and to what extent the implantation of an absorbable polymer DES impairs coronary vasomotion. This sub-study of the DESSOLVE II trial included 19 APSES Mistent(®) and 10 ZES Endeavor(®) patients. Incremental atrial pacing and quantitative coronary angiography were used to assess vasomotion proximal and distal to the stent and in a reference segment at 9 months after implantation. Percent changes in vessel diameter with pacing versus baseline were calculated and compared. Vasomotor response of the APSES group was also compared with changes observed in a historical group of 17 patients implanted with a 1st-gen sirolimus-eluting stent (SES). Normal vasomotion (vasodilatation) was preserved and of comparable magnitude in the APSES and in the ZES group both proximally (P = 0.34) and distally (P = 0.38) to the stent. This finding was not observed in the 1st-gen SES group showing marked pacing-induced vasoconstriction at both stent edges (P absorbable polymer sirolimus-eluting stent is associated with preserved coronary vasomotion, comparable to that observed after implantation of the Endeavor(®) ZES, and distinct from 1st-gen SES which induce coronary vasomotor dysfunction. © 2015 Wiley Periodicals, Inc.

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

International Nuclear Information System (INIS)

Dys, Krzysztof; Drelichowska-Durawa, Justyna; Dołega-Kozierowski, Bartosz; Lis, Michał; Sokratous, Kyriakos; Iwanowski, Wojciech; Drelichowski, Stanisław; Witkiewicz, Wojciech

2013-01-01

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. 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. 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. Frequency of angioplasty and vascular stent implantation procedures is increased in patients

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

OpenAIRE

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

2015-01-01

Absorbable metals have been widely tested in various in vitro settings using cells to evaluate their possible suitability as an implant material. However, there exists a gap between in vivo and in vitro test results for absorbable materials. A lot of traditional in vitro assessments for permanent materials are no longer applicable to absorbable metallic implants. A key step is to identify and test the relevant microenvironment and parameters in test systems, which should be adapted according ...

Bioresorbable vascular scaffold (BVS) for in-stent chronic total occlusion: Antegrade recanalization and IVUS-guided BVS implantation by radial access

Energy Technology Data Exchange (ETDEWEB)

Medda, Massimo [Interventional Cardiology Unit, Istituto Clinico Sant' Ambrogio, Milano (Italy); Casilli, Francesco, E-mail: frcasill@tin.it [Interventional Cardiology Unit, Istituto Clinico Sant' Ambrogio, Milano (Italy); Bande, Marta [Interventional Cardiology Unit, Istituto Clinico Sant' Ambrogio, Milano (Italy); Latini, Maria Giulia [Cardiologia Interventistica, IRCCS Policlinico San Donato, San Donato Milanese, Milano (Italy); Ghommidh, Mehdi [Interventional Cardiology Unit, Istituto Clinico Sant' Ambrogio, Milano (Italy); Del Furia, Francesca [Unità Operativa di Cardiologia, Azienda Ospedaliera di Melegnano, Milano (Italy); Inglese, Luigi [Interventistica Cardiovascolare, Gruppo Sanitario Policlinico di Monza, Milano (Italy)

2016-01-15

The completely absorbable stents represent one of the latest innovations in the field of interventional cardiology, prospecting the possibility of “vascular repair”. In the published trials (ABSORB Cohort A and B, ABSORB EXTEND, and ABSORB II, III and IV) chronic total occlusions (CTOs) were considered an exclusion criteria. More recently the CTO-ABSORB pilot study demonstrated the safety and feasibility of bioresorbable vascular scaffold (BVS) use in case of CTO recanalization. We present the first case, to our knowledge, of in-stent occlusion successfully treated with an everolimus-eluting BVS and discuss its potential advantages in such kind of lesions.

Bioresorbable vascular scaffold (BVS) for in-stent chronic total occlusion: Antegrade recanalization and IVUS-guided BVS implantation by radial access

International Nuclear Information System (INIS)

Medda, Massimo; Casilli, Francesco; Bande, Marta; Latini, Maria Giulia; Ghommidh, Mehdi; Del Furia, Francesca; Inglese, Luigi

2016-01-01

The completely absorbable stents represent one of the latest innovations in the field of interventional cardiology, prospecting the possibility of “vascular repair”. In the published trials (ABSORB Cohort A and B, ABSORB EXTEND, and ABSORB II, III and IV) chronic total occlusions (CTOs) were considered an exclusion criteria. More recently the CTO-ABSORB pilot study demonstrated the safety and feasibility of bioresorbable vascular scaffold (BVS) use in case of CTO recanalization. We present the first case, to our knowledge, of in-stent occlusion successfully treated with an everolimus-eluting BVS and discuss its potential advantages in such kind of lesions.

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

Science.gov (United States)

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

2009-05-01

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

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

Science.gov (United States)

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

1997-01-01

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

Insertion of a single double-J stent for bilateral open ureteral reimplantation: introducing a novel technique and assessment of feasibility.

Science.gov (United States)

Nabavizadeh, Behnam; Keihani, Sorena; Hosseini Sharifi, Seyed Hossein; Kajbafzadeh, Abdol-Mohammad

2016-07-01

To propose a novel technique for bilateral placement of a single double-J stent during bilateral open ureteral reimplantation in order to reduce the intravesical length of stent and potentially minimize the irritative symptoms. A retrospective chart review was performed to find patients who underwent bilateral open ureteral reimplantation. According to the patient's age, an appropriate single double-J stent is used for stenting both ureters after open reimplantation using the Politano-Leadbetter technique. The stent is fixed to the bladder wall with a 4-0 chromic absorbable suture in the midline, superior to the intertrigonal ridge. A non-absorbable suture is also fixed to the stent in the midline as an extraction string. From June 2009 to July 2013, 20 patients underwent bilateral ureteric surgery. Twelve (60 %) were female. Patients' age ranged from 3 months to 2 years. Double-J stents were successfully removed within 2 weeks postoperatively in all patients. This technique might reduce the stent-related symptoms after open bladder surgery for bilateral ureteral surgery. Using this technique will reduce the redundant mass of ureteral stents in bladder and potentially minimize the trigonal irritation and subsequent pain and discomfort.

Stent insertion in patients with malignant biliary obstruction: problems of the Hanaro stent

Energy Technology Data Exchange (ETDEWEB)

Kwon, Jae Hyun; Seong, Chang Kyu; Shin, Tae Beom; Kim, Yong Joo [School of Medicine, Kyungpook National Univ., Daegu (Korea, Republic of); Jung, Gyoo Sik [School of Medicine, Kosin National Univ., Pusan (Korea, Republic of); Park, Byeung Ho [School of Medicine, Donga National Univ., Pusan (Korea, Republic of)

2002-07-01

To investigate the problems of the Hanaro stent (Solco Intermed, Seoul, Korea) when used in the palliative treatment of patients with inoperable malignant biliary obstruction. Between January 2000 and May 2001, the treatment of 46 patients with malignant biliary obstruction involved percutaneous placement of the Hanaro stent. Five patients encountered problems during removal of the stent's introduction system. The causes of obstruction were pancreatic carcinoma (n=2), cholangiocarcinoma (n=2), and gastric carcinoma with biliary invasion (n=1). In one patient, percutaneous transhepatic cholangiography and stent insertion were performed as a one-step procedure, while the others underwent conventional percutaneous transhepatic biliary drainage for at least two days prior to stent insertion. A self-expandable Hanaro stent, 8-10 mm in deameter and 50-100 mm in lengh, and made from a strand of nitinol wire, was used in all cases. Among the five patients who encountered problems, breakage of the olive tip occourred in three, upward displacement of the stent in two, and improper expansion of the distal portion of the stent, unrelated with the obstruction site, in one. The broken olive tip was pushed to the duodenum in two cases and to the peripheral intrahepatic duct in one. Where the stent migrated during withdrawal of its introduction system, an additional stent was inserted. In one case, the migrated stent was positioned near the liver capsule and the drainage catheter could not be removed. Although the number of patients in this study was limited, some difficulties were encountered in withdrawing the stent's introduction system. To prevent the occurrence of this unusual complication, the stent should be appropriately expansile, and shape in the olive tip should be considered.

A computational study of crimping and expansion of bioresorbable polymeric stents

Science.gov (United States)

Qiu, T. Y.; Song, M.; Zhao, L. G.

2017-10-01

This paper studied the mechanical performance of four bioresorbable PLLA stents, i.e., Absorb, Elixir, Igaki-Tamai and RevaMedical, during crimping and expansion using the finite element method. Abaqus CAE was used to create the geometrical models for the four stents. A tri-folded balloon was created using NX software. For the stents, elastic-plastic behaviour was used, with hardening implemented by considering the increase of yield stress with the plastic strain. The tri-folded balloon was treated as linear elastic. To simulate the crimping of stents, a set of 12 rigid plates were generated around the stents with a radially enforced displacement. During crimping, the stents were compressed from a diameter of 3 mm to 1.2 mm, with the maximum stress developed at both inner and outer sides of the U-bends. During expansion, the stent inner diameter increased to 3 mm at the peak pressure and then recoiled to different final diameters after balloon deflation due to different stent designs. The maximum stress was found again at the U-bends of stents. Diameter change, recoiling effect and radial strength/stiffness were also compared for the four stents to assess the effect of design variation on stent performance. The effect of loading rate on stent deformation was also simulated by considering the time-dependent plastic behaviour of polymeric material.

Expandable metallic stents: An experimental study in the nasolacrimal systems of dogs

Energy Technology Data Exchange (ETDEWEB)

Song, Ho Young [Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of); Lee, Jeong Min; Han, Young Min; Hwang, Eui Il; Chung, Gyung Ho; Shon, Myung Hee; Kim, Chong Soo; Choi, Ki Chul [Chonbuk National University Medical School, Chonju(Korea, Republic of)

1993-11-15

Balloon dacryocystoplasty has been reported to be a safe, easy and effective nonoperative treatment for nasolacrimal stenosis. The results were not encouraging, however, because of its high failure and recurrence rates. To evaluate the feasibility of using modified Gianturco expandable metallic stents for maintenance of the dilated nasolacrimal system(NLS), 20 stents of 3 mm in diameter and 10 mm long were placed in 20 nasolacrimal ducts of 10 dogs for 1 month to 10 months. It was more difficult to introduce the stents into the proximal portion(A) of the NLS than into the distal portion(B) due to the narrow and bony canal of the A portion. Twenty stents showed no migration in follow-up studies of up to 10 months. One complete occlusion occurred in a stent placed in A portion. Autopsy studies showed stents were covered with epithelium within 2 months after placement. Our experience suggest that the placement of Gianturco self-expandable stents may be a useful method of dilating and maintaining the luminal diameter of the NLS, although care must be taken to select the proper stent size.

Expandable metallic stents: An experimental study in the nasolacrimal systems of dogs

International Nuclear Information System (INIS)

Song, Ho Young; Lee, Jeong Min; Han, Young Min; Hwang, Eui Il; Chung, Gyung Ho; Shon, Myung Hee; Kim, Chong Soo; Choi, Ki Chul

1993-01-01

Balloon dacryocystoplasty has been reported to be a safe, easy and effective nonoperative treatment for nasolacrimal stenosis. The results were not encouraging, however, because of its high failure and recurrence rates. To evaluate the feasibility of using modified Gianturco expandable metallic stents for maintenance of the dilated nasolacrimal system(NLS), 20 stents of 3 mm in diameter and 10 mm long were placed in 20 nasolacrimal ducts of 10 dogs for 1 month to 10 months. It was more difficult to introduce the stents into the proximal portion(A) of the NLS than into the distal portion(B) due to the narrow and bony canal of the A portion. Twenty stents showed no migration in follow-up studies of up to 10 months. One complete occlusion occurred in a stent placed in A portion. Autopsy studies showed stents were covered with epithelium within 2 months after placement. Our experience suggest that the placement of Gianturco self-expandable stents may be a useful method of dilating and maintaining the luminal diameter of the NLS, although care must be taken to select the proper stent size

Coronary Stents in Diabetic Patients: State of the Knowledge.

Science.gov (United States)

Codner, Pablo; Gurm, Hitinder Singh; Motivala, Apurva

2017-04-01

This review article aims to summarize the findings of the most relevant research that compared the use of paclitaxel vs. "limus" based drug eluting stent (DES) in diabetic patients and to define the current state of knowledge with new stent technologies in this patient population. Since drug eluting stents (DES) were introduced, it has been of great interest to establish whether paclitaxel or sirolimus eluting stents have the same safety and efficacy features for patients with coronary artery disease. The answer to this question is particularly relevant for diabetic patients. Several randomized trials, registry-based studies, and meta-analyses have assessed the performance of these different DES in diabetic patients. The most recently published data favors limus over paclitaxel DES in diabetic patients, but most of these studies compared first vs. second generation DES with the inherent caveats of comparing different platforms, alloys, and drug delivery vehicles. In this literature review, we found that there is robust evidence favoring the use of DES over bare metal stents in diabetic patients with coronary artery disease. We also found that the current state of knowledge is that the everolimus eluting stents have better safety and efficacy than paclitaxel eluting stents in diabetic patients and hence should be the preferred choice. New revascularization strategies including bio-absorbable scaffolds, polymer free stents, and bio-degradable polymers are being studied in diabetic patients with encouraging results.

A novel self-expanding fully retrievable intracranial stent (SOLO): experience in nine procedures of stent-assisted aneurysm coil occlusion

International Nuclear Information System (INIS)

Liebig, Thomas; Henkes, Hans; Reinartz, Joerg; Miloslavski, Elina; Kuehne, Dietmar

2006-01-01

The endovascular treatment of large and broad-necked aneurysms may require the use of a remodelling balloon or a stent system to achieve proper occlusion while maintaining the patency of the parent vessel. With the advent of self-expanding stents that can be delivered through a microcatheter, this kind of treatment has improved and problems with the previously used balloon expandable stents have largely been overcome. However, rigidity, insufficient trackability, and limited or non-existent retrievability may still restrict the application of self-expanding stents in some situations. Recently, a stent system with a new and different design has been introduced. This stent is highly flexible, fully retrievable, and can be delivered through a standard 0.021-inch microcatheter without a wire. We describe the first nine cases of stent-assisted coil occlusion of intracranial aneurysms with the use of this stent system. Between May and June of 2004, nine patients with large or broad-necked aneurysms were treated in two endovascular centres. The anatomy of the aneurysms and parent vessels, technical details of the procedure, performance of the stent system, and follow-up results were evaluated. In all procedures, the SOLO stent could be introduced without difficulty, in one procedure after positioning of a different self-expanding stent system had failed due to vessel tortuosity. Overlapping stents were placed in one patient and stent retrieval or repositioning was successfully performed in two procedures. There was no interference or limitation of subsequent coil occlusion after stenting. With regard to the stent, immediate postprocedure and follow-up angiograms were unremarkable in terms of thromboembolic events and signs of intimal hyperplasia. From our experience, we conclude that the SOLO stent shows satisfactory performance overall. Its unique design gives the stent properties that may help overcome some of the difficulties experienced with other self

Combined-stent covered technique and single covered stent technique for transjugular intrahepatic porto-systemic shunt: a prospective randomized controlled study

International Nuclear Information System (INIS)

Wang Changming; Li Xuan; Fu Jun; Lu Xianjun; Luan Jingyuan; Li Tianrun; Zhao Jun; Dong Guoxiang

2014-01-01

Objective: To compare the technique of combined stents with that of single stent-graft for the construction of transjugular intrahepatic porto-systemic shunt (TIPS) and to discuss their clinical outcomes. Methods: During the period from April 2011 to Dec. 2012, a total of 30 patients with upper gastrointestinal bleeding due to portal hypertension were admitted to the hospital. TIPS procedure was carried out in all the 30 patients. The patients were randomly allocated into either combined-stent group (n=17) or stent-graft group (control group, n=13) on the basis of a computer-generated randomization sequence. The PSC quality control, the patency rate of portal vein branches and the shunts, the incidence of encephalopathy and the survival rate of the two groups were documented and analyzed. Results: Technical success rate was 100%. After the treatment, in both groups the PSG became significantly lower than the PSG determined before the treatment (P<0.000). According to quality control chart, the of combined stents was superior to stent-graft technique in effectively controlling PSG. Five days after TIPS, the ammonia level in the combined- stent group was significantly decreased (P=0.029), while in the control group the ammonia level showed no significant changes (P=0.065). One patient died shortly after TIPS. The median follow- up time was 181 days. During the follow-up period death occurred in 3 cases in each group. The difference in the survival rate between the two groups was no significant (P=0.906). Of the three patients who developed encephalopathy, two were in the combined-stent group and one was in the control group. After medication the symptoms of encephalopathy were relieved. The patency rate of the shunts was 100% and the re-bleeding rate was 0% for both groups. The patency rate of portal vein branches was significantly higher in the combined-stent group than that in the control group (P=0.039). Conclusion: For the construction of TIPS, the technique of

Treatment of intracranial stenoses using the Neuroform stent system: initial experience in five cases

International Nuclear Information System (INIS)

Haehnel, Stefan; Hartmann, Marius; Ringleb, Peter

2006-01-01

We assessed the technical feasibility of balloon-assisted angioplasty with consecutive stenting using a flexible, self-expanding neurovascular stent for the treatment of intracranial arteriosclerotic vascular stenoses. Five consecutive patients with symptomatic drug-resistant stenoses of the intracranial internal carotid artery (ICA) or the main stem of the middle cerebral artery (MCA) were treated by balloon-assisted angioplasty with consecutive stenting using the Neuroform stent system. Balloon dilatation of the stenoses and consecutive stent placement with complete coverage of the stenoses was feasible in all patients. One patient suffered acute thrombosis distally to the stented vessel segment which was successfully treated by fibrinolysis, and one patient suffered acute subarachnoid and parenchymal hemorrhage probably due to vessel perforation. In the other three patients, no complications occurred during or immediately after angioplasty. All patients were free of further ischemic events up to the 6-month follow-up. Our findings demonstrate that the Neuroform stent system can used successfully for the treatment of intracranial stenoses of the ICA and the main stem of the MCA. Although immediate angiographic results are promising, long-term angiographic and clinical follow-up is essential to demonstrate long-term outcome. (orig.)

Mechanical behavior of peripheral stents and stent-vessel interaction: A computational study

Science.gov (United States)

Dottori, Serena; Flamini, Vittoria; Vairo, Giuseppe

2016-05-01

In this paper stents employed to treat peripheral artery disease are analyzed through a three-dimensional finite-element approach, based on a large-strain and large-displacement formulation. Aiming to evaluate the influence of some stent design parameters on stent mechanics and on the biomechanical interaction between stent and arterial wall, quasi-static and dynamic numerical analyses are carried out by referring to computational models of commercially and noncommercially available versions of both braided self-expandable stents and balloon-expandable stents. Addressing isolated device models, opening mechanisms and flexibility of both opened and closed stent configurations are numerically experienced. Moreover, stent deployment into a stenotic peripheral artery and possible postdilatation angioplasty (the latter for the self-expandable device only) are simulated by considering different idealized vessel geometries and accounting for the presence of a stenotic plaque. Proposed results highlight important differences in the mechanical response of the two types of stents, as well as a significant influence of the vessel shape on the stress distributions arising upon the artery-plaque system. Finally, computational results are used to assess both the stent mechanical performance and the effectiveness of the stenting treatment, allowing also to identify possible critical conditions affecting the risk of stent fracture, tissue damage, and/or pathological tissue response.

Expandable stents.

Science.gov (United States)

Nesbitt, J C; Carrasco, H

1996-05-01

tissue is less likely to occur in areas of established scar than in areas of acute inflammation. In circumstances in which it is essential that a stent remain only temporarily, an expandable stent should not be inserted in favor of a silicone stent, which can be removed. In the future, expandable stents may have silicone coverings or may be constructed of materials that facilitate removal. Until that time, expandable stents should be considered permanent and nonremovable. Subtle differences exist among the available stents. Standard is low-profile expandable construction from wire mesh. A relatively minor difference is the slightly wider expansibility of the Gianturco stent, a quality that makes it the best suited of the three stents for lesions that involve tracheomalacia. Perhaps the only major difference between the Wallstent and the Gianturco and Palmaz stents is its better ability to conform to tortuous lesions. In an acutely angled stricture, a Wallstent offers a better opportunity for successful placement than other stents. The filamentous meshwork of the Wallstent allows it to bend and conform better to distorted airways. The Gianturco and Palmaz stents have little longitudinal elasticity, which makes them less effective in a tortuous or highly angulated airway stenosis. Expandable stents have demonstrated their efficacy and exposed their limitations in the treatment of airway stenoses. Refinements in design should help to lessen specific disadvantages and problems. Covered expandable stents, a realistic prospect, have specific advantages over standard expandable stents; they will be removable and prevent tumor ingrowth. Current investigative work with such prostheses for the vascular system may provide the foundation for their investigative use in the airway. In essence, two categories of expandable stents are evolving, covered and uncovered, each having unique features adaptable to the specific clinical needs.

The forgotten ureteric JJ stent and its prevention: a prospective audit of the value of a ureteric stent logbook.

Science.gov (United States)

Thomas, A Z; Casey, R G; Grainger, R; McDermott, T; Flynn, R; Thornhill, J A

2007-01-01

Temporary ureteric stent insertion is an integral part of modern endo-urological practice. Delayed stent removal or forgotten stents are associated with increased patient morbidity and complications which are often difficult to manage. We prospectively audited our ureteric stent insertion and removal logbook system to determine the value and effectiveness of our stent follow-up. Over a 1-year period, 210 ureteric stents were inserted in our urological unit. Of these, 47 (22.4%) patients were unaccounted as having their stents removed within the stent logbooks. One patient was lost to follow-up and re-presented with stent encrustation 10 months later. Our results in this audit suggest that our system of ureteric stent follow-up is not effective. We have now introduced a new system that we feel is a safer and a satisfactory alternative to the stent logbooks. This includes a patient education leaflet and removal date scheduling prior to discharge from hospital.

Biodegradable Metals for Cardiovascular Stent Application: Interests and New Opportunities

Science.gov (United States)

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

Biodegradable Metals for Cardiovascular Stent Application: Interests and New Opportunities

Directory of Open Access Journals (Sweden)

Maryam Moravej

2011-06-01

Full Text Available 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.

Evaluation of the short- and long-term safety and therapy outcomes of the everolimus-eluting bioresorbable vascular scaffold system in patients with coronary artery stenosis: Rationale and design of the German–Austrian ABSORB RegIstRy (GABI-R)

Energy Technology Data Exchange (ETDEWEB)

Nef, Holger, E-mail: holger.nef@innere.med.uni-giessen.de [University of Giessen, Medizinische Klinik I, Department of Cardiology, Giessen (Germany); Wiebe, Jens [University of Giessen, Medizinische Klinik I, Department of Cardiology, Giessen (Germany); Achenbach, Stefan [University of Erlangen, Medizinische Klinik II, Department of Cardiology, Erlangen (Germany); Münzel, Thomas [Department of Medicine II, University Medical Center, Johannes Gutenberg University Mainz, Mainz (Germany); Naber, Christoph [Klinik für Kardiologie und Angiologie, Elisabeth-Krankenhaus, Essen (Germany); Richardt, Gert [Herzzentrum, Segeberger Kliniken GmbH, Bad Segeberg (Germany); Mehilli, Julinda [Department of Cardiology, Klinikum Großhadern, Ludwig- Maximilian Universität, Munich (Germany); Wöhrle, Jochen [Department of Internal Medicine II, University of Ulm, Ulm (Germany); Neumann, Till; Biermann, Janine [University of Essen, Department of Cardiology, Essen (Germany); Zahn, Ralf [Abteilung für Kardiologie, Herzzentrum Ludwigshafen, Ludwigshafen (Germany); Kastner, Johannes [Department of Cardiology, University of Vienna Medical School, Vienna (Austria); Schmermund, Axel [CCB, Cardioangiologisches Centrum Bethanien, Frankfurt (Germany); Pfannebecker, Thomas [Abbott Vascular Deutschland GmbH, Wetzlar (Germany); Schneider, Steffen; Limbourg, Tobias [Institut für Herzinfarktforschung, Ludwigshafen (Germany); Hamm, Christian W. [University of Giessen, Medizinische Klinik I, Department of Cardiology, Giessen (Germany); Kerckhoff Heart and Thorax Center, Department of Cardiology, Bad Nauheim (Germany)

2016-01-15

Background: Third-generation drug-eluting metal stents are the gold standard for treatment of coronary artery disease. The permanent metallic caging of the vessel, however, can result in limited vasomotion, chronic inflammation, and late expansive remodeling, conditions that can lead to late and very late stent thrombosis. The development of bioresorbable scaffolds (BRSs) promises advantages over metal stents due to complete biodegradation within 2–4 years. Theoretically, since vessel scaffolding is temporary and no permanent implant remains in the vessel, BRSs, as opposed to metal stents, once degraded would no longer be potential triggers for stent-related adverse events or side effects. Methods/design: The short- and long-term outcome after implantation of an everolimus-eluting, poly-L-lactic acid-based bioresorbable scaffold system (ABSORB, Abbott Vascular, Santa Clara, CA, USA) in the world-wide greatest all-comers cohort will be evaluated in the prospective, non-interventional, multicenter German–Austrian ABSORB RegIstRy (GABI-R). GABI-R will include over 5000 patients from about 100 study sites in Austria and Germany. Safety endpoints such as cardiac death, myocardial infarction, and clinically driven percutaneous or surgical target lesion and vessel revascularization will be evaluated during hospitalization and in the follow-up period (minimum of 5 years). Conclusion: Although two randomized controlled trials and several registries have documented safety and efficacy as well as non-inferiority of this everolimus-eluting ABSORB device compared with drug-eluting metal stents, the current knowledge regarding clinical application, treatment success, and long-term safety of using this BRS in daily routine is limited. Thus, the goal of GABI-R is to address this lack of information. - Highlights: • The GABI-R addresses a lack of data about bioresorbable scaffolds in daily practice. • 5000 patients with minimal in- and exclusion criteria at 100 sites will

Evaluation of the short- and long-term safety and therapy outcomes of the everolimus-eluting bioresorbable vascular scaffold system in patients with coronary artery stenosis: Rationale and design of the German–Austrian ABSORB RegIstRy (GABI-R)

International Nuclear Information System (INIS)

Nef, Holger; Wiebe, Jens; Achenbach, Stefan; Münzel, Thomas; Naber, Christoph; Richardt, Gert; Mehilli, Julinda; Wöhrle, Jochen; Neumann, Till; Biermann, Janine; Zahn, Ralf; Kastner, Johannes; Schmermund, Axel; Pfannebecker, Thomas; Schneider, Steffen; Limbourg, Tobias; Hamm, Christian W.

2016-01-01

Background: Third-generation drug-eluting metal stents are the gold standard for treatment of coronary artery disease. The permanent metallic caging of the vessel, however, can result in limited vasomotion, chronic inflammation, and late expansive remodeling, conditions that can lead to late and very late stent thrombosis. The development of bioresorbable scaffolds (BRSs) promises advantages over metal stents due to complete biodegradation within 2–4 years. Theoretically, since vessel scaffolding is temporary and no permanent implant remains in the vessel, BRSs, as opposed to metal stents, once degraded would no longer be potential triggers for stent-related adverse events or side effects. Methods/design: The short- and long-term outcome after implantation of an everolimus-eluting, poly-L-lactic acid-based bioresorbable scaffold system (ABSORB, Abbott Vascular, Santa Clara, CA, USA) in the world-wide greatest all-comers cohort will be evaluated in the prospective, non-interventional, multicenter German–Austrian ABSORB RegIstRy (GABI-R). GABI-R will include over 5000 patients from about 100 study sites in Austria and Germany. Safety endpoints such as cardiac death, myocardial infarction, and clinically driven percutaneous or surgical target lesion and vessel revascularization will be evaluated during hospitalization and in the follow-up period (minimum of 5 years). Conclusion: Although two randomized controlled trials and several registries have documented safety and efficacy as well as non-inferiority of this everolimus-eluting ABSORB device compared with drug-eluting metal stents, the current knowledge regarding clinical application, treatment success, and long-term safety of using this BRS in daily routine is limited. Thus, the goal of GABI-R is to address this lack of information. - Highlights: • The GABI-R addresses a lack of data about bioresorbable scaffolds in daily practice. • 5000 patients with minimal in- and exclusion criteria at 100 sites will

Bilateral metal stents for hilar biliary obstruction using a 6Fr delivery system: outcomes following bilateral and side-by-side stent deployment.

Science.gov (United States)

Law, Ryan; Baron, Todd H

2013-09-01

Controversy exists on optimal endoscopic management for palliation of malignant hilar obstruction, with advocates for metal "side-by-side" (SBS) and "stent-in-stent" (SIS) techniques. We sought to evaluate the technical feasibility, efficacy, and outcomes of bilateral biliary self-expanding metal stents (SEMS) for treatment of malignant hilar obstruction using a stent with a 6Fr delivery system. This was a single-center, retrospective review of all patients who underwent bilateral placement of Zilver® biliary SEMS for malignant hilar obstruction from January 2010 to August 2012. Patients underwent endoscopic retrograde cholangiopancreatography with placement of stents using either the SIS or SBS stent techniques. Twenty-four patients (19 men, mean age 63 years) underwent bilateral stenting for malignant hilar obstruction during the study period. Seventeen and seven patients underwent the SBS and SIS technique, respectively. Cholangiocarcinoma (n=14) was the most common cause of hilar obstruction. Initial technical success was achieved in 24/24 (100%) of patients; however, 12 (50%) patients required re-intervention during the study period (median 98 days). Comparison of the SBS and SIS groups revealed no statistical difference with respect to need for re-intervention (P=0.31), successful re-intervention (P=0.60), or procedural length (P=0.89). Use of bilateral Zilver® SEMS in either the SBS or SIS configuration is safe, technically feasible, and effective for drainage of malignant hilar obstruction; however, duration of stent patency and procedure-free survival remain variable.

Bioabsorbable coronary stents--are these the next big thing in coronary angioplasty?

Science.gov (United States)

Balla, Sudarshan; Aggarwal, Kul; Nistala, Ravi

2010-06-01

The role of percutaneous coronary intervention (PCI) in the treatment of coronary artery disease has grown at an astronomical pace. Drug eluting stents (DES) offer advantages over bare metal stents (BMS) such as reduction in early in-stent restenosis rates. However, they have disadvantages like from increased late stent thrombosis when compared with BMS. Furthermore, recent data suggest endothelial dysfunction in the DES stented segments of the arteries. Currently, bioabsorbable stents are under development to avert the complications of DES such as stent thrombosis via degradation of the stent over time. The hypothetical advantage of leaving behind a natural vessel and restoring vasoreactivity may be the almost normal physiology which can be achieved after an intervention with a stent. The ABSORB and the PROGRESS AMS are two of the recent clinical trials that have looked at the outcomes of using bioabsorbable stents. So far, data from these and other studies has yielded mixed results in terms of angiographic and clinical outcomes. Newer stents such as REVA and WHISPER are presently being tested in preclinical and clinical trials. The landscape for bioabsorbable stents is constantly evolving through continued improvisation on existing technology and emergence of new technology. Large scale randomized trials are still needed with adequate long term follow-up for safety and benefits to have mainstream application in coronary artery disease, bioabsorbable stents are a promising innovation in the field of PCI. We review some of the patents and the data that is emerging on bioabsorbable stents in addition to currently ongoing clinical trials.

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

Science.gov (United States)

Werner, Martin

2017-08-01

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

Economic Outcomes of Bioresorbable Vascular Scaffolds Versus Everolimus-Eluting Stents in Patients Undergoing Percutaneous Coronary Intervention: 1-Year Results From the ABSORB III Trial.

Science.gov (United States)

Baron, Suzanne J; Lei, Yang; Chinnakondepalli, Khaja; Vilain, Katherine; Magnuson, Elizabeth A; Kereiakes, Dean J; Ellis, Stephen G; Stone, Gregg W; Cohen, David J

2017-04-24

The purpose of this study was to evaluate the economic impact of the Absorb bioresorbable vascular scaffold compared with the Xience everolimus-eluting stent in patients undergoing percutaneous coronary intervention. The ABSORB III trial (Everolimus-Eluting Bioresorbable Scaffolds for Coronary Artery Disease) demonstrated that the Absorb scaffold was noninferior to the Xience stent with respect to target lesion failure at 1 year. Whether health care costs differ between the Absorb scaffold and the Xience stent is unknown. We performed a prospective health economic study alongside the ABSORB III trial, in which patients undergoing percutaneous coronary intervention for stable or unstable angina were randomized to receive the Absorb scaffold (n = 1,322) or Xience stent (n = 686). Resource use data were collected through 1 year of follow-up. Costs were assessed using resource-based accounting (for procedures), MedPAR data (for other index hospitalization costs), and Medicare reimbursements (for follow-up costs and physician fees). Initial procedural costs were higher with the Absorb scaffold than the Xience stent ($6,316 ± 1,892 vs. $6,103 ± 1,895; p = 0.02), driven mainly by greater balloon catheter use and the higher cost of the scaffold in the Absorb group. Nonetheless, index hospitalization costs ($15,035 ± 2,992 for Absorb vs. $14,903 ± 3,449 for Xience; p = 0.37) and total 1-year costs ($17,848 ± 6,110 for Absorb vs. $17,498 ± 7,411 for Xience; p = 0.29) were similar between the 2 groups. Although initial procedural costs were higher with the Absorb scaffold, there were no differences in total 1-year health care costs between the 2 cohorts. Longer term follow-up is needed to determine whether meaningful cost savings emerge after scaffold resorption. (A Clinical Evaluation of Absorb™ BVS, the Everolimus-Eluting Bioresorbable Vascular Scaffold in the Treatment of Subjects With de Novo Native Coronary Artery Lesions; NCT01751906). Copyright © 2017

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

Science.gov (United States)

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.

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

Science.gov (United States)

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

2015-09-01

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

XIENCE V everolimus-eluting coronary stent system: a novel second generation drug-eluting stent

NARCIS (Netherlands)

Beijk, Marcel A. M.; Piek, Jon J.

2007-01-01

Drug-eluting stents (DES) have been shown to be safe and significantly reduce clinical events and angiographic restenosis in the percutaneous treatment of coronary artery disease. Currently, three DES have been approved in Europe and Northern America: the sirolimus-eluting stent (SES), the

Auxetic coronary stent endoprosthesis

DEFF Research Database (Denmark)

Amin, Faisal; Ali, Murtaza Najabat; Ansari, Umar

2014-01-01

BACKGROUND: Cardiovascular heart disease is one of the leading health issues in the present era and requires considerable health care resources to prevent it. The present study was focused on the development of a new coronary stent based on novel auxetic geometry which enables the stent to exhibit...... a negative Poisson's ratio. Commercially available coronary stents have isotropic properties, whereas the vascular system of the body shows anisotropic characteristics. This results in a mismatch between anisotropic-isotropic properties of the stent and arterial wall, and this in turn is not favorable...... for mechanical adhesion of the commercially available coronary stents with the arterial wall. It is believed that an auxetic coronary stent with inherent anisotropic mechanical properties and negative Poisson's ratio will have good mechanical adhesion with the arterial wall. METHODS: The auxetic design...

Randomised comparison of a bioresorbable everolimus-eluting scaffold with a metallic everolimus-eluting stent for ischaemic heart disease caused by de novo native coronary artery lesions

DEFF Research Database (Denmark)

Chevalier, Bernard; Onuma, Yoshinobu; van Boven, Ad J

2016-01-01

AIMS: The one-year randomised data of the ABSORB II trial showed that the everolimus-eluting bioresorbable scaffold and the everolimus-eluting metallic stent were comparable for the composite secondary clinical outcomes of patient-oriented composite endpoint (PoCE) and device-oriented composite...... Clara, CA, USA) or treatment with an everolimus-eluting metallic stent (XIENCE; Abbott Vascular). The trial enrolled 501 patients. Clinical follow-up at two years was available in 320 patients in the Absorb BVS arm and 160 patients in the XIENCE arm. At two years, the PoCE for the Absorb and XIENCE arms......-six percent and 34% of patients remained on DAPT at two years, respectively. Ninety-two percent of patients in both arms remained on aspirin. CONCLUSIONS: Two-year clinical results demonstrate sustained low rates of PoCE, MACE, DoCE and TVF with the Absorb BVS as compared to the XIENCE stent....

Spectral Imaging for Intracranial Stents and Stent Lumen.

Science.gov (United States)

Weng, Chi-Lun; Tseng, Ying-Chi; Chen, David Yen-Ting; Chen, Chi-Jen; Hsu, Hui-Ling

2016-01-01

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. 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. 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 stent lumen (160.03 ±37.79; P 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.

'Stent in a stent'--an alternative technique for removing partially covered stents following sleeve gastrectomy complications.

Science.gov (United States)

Vasilikostas, Georgios; Sanmugalingam, Nimalan; Khan, Omar; Reddy, Marcus; Groves, Chris; Wan, Andrew

2014-03-01

Endoscopic stenting is a relatively new technique for the treatment of post sleeve gastrectomy complications. Partially covered stents are used in this method to minimise the risk of migration but they are associated with difficulties with removal. Patients requiring emergency stenting following sleeve gastrectomy underwent insertion of a partially covered metallic stent. One month later, if the stent was not easily removable, a fully covered overlapping stent was inserted and the patient was readmitted 2 weeks later for removal of both stents. Four patients required stenting following sleeve gastrectomy leaks, and one patient required stenting for a stricture. In these cases, a 'stent in a stent' technique was used for removal. This technique allows the safe removal of partially covered stents inserted following sleeve gastrectomy complications.

A sirolimus-eluting bioabsorbable polymer-coated stent (MiStent) versus an everolimus-eluting durable polymer stent (Xience) after percutaneous coronary intervention (DESSOLVE III): a randomised, single-blind, multicentre, non-inferiority, phase 3 trial.

Science.gov (United States)

de Winter, Robbert J; Katagiri, Yuki; Asano, Taku; Milewski, Krzysztof P; Lurz, Philipp; Buszman, Pawel; Jessurun, Gillian A J; Koch, Karel T; Troquay, Roland P T; Hamer, Bas J B; Ophuis, Ton Oude; Wöhrle, Jochen; Wyderka, Rafał; Cayla, Guillaume; Hofma, Sjoerd H; Levesque, Sébastien; Żurakowski, Aleksander; Fischer, Dieter; Kośmider, Maciej; Goube, Pascal; Arkenbout, E Karin; Noutsias, Michel; Ferrari, Markus W; Onuma, Yoshinobu; Wijns, William; Serruys, Patrick W

2018-02-03

MiStent is a drug-eluting stent with a fully absorbable polymer coating containing and embedding a microcrystalline form of sirolimus into the vessel wall. It was developed to overcome the limitation of current durable polymer drug-eluting stents eluting amorphous sirolimus. The clinical effect of MiStent sirolimus-eluting stent compared with a durable polymer drug-eluting stents has not been investigated in a large randomised trial in an all-comer population. We did a randomised, single-blind, multicentre, phase 3 study (DESSOLVE III) at 20 hospitals in Germany, France, Netherlands, and Poland. Eligible participants were any patients aged at least 18 years who underwent percutaneous coronary intervention in a lesion and had a reference vessel diameter of 2·50-3·75 mm. We randomly assigned patients (1:1) to implantation of either a sirolimus-eluting bioresorbable polymer stent (MiStent) or an everolimus-eluting durable polymer stent (Xience). Randomisation was done by local investigators via web-based software with random blocks according to centre. The primary endpoint was a non-inferiority comparison of a device-oriented composite endpoint (DOCE)-cardiac death, target-vessel myocardial infarction, or clinically indicated target lesion revascularisation-between the groups at 12 months after the procedure assessed by intention-to-treat. A margin of 4·0% was defined for non-inferiority of the MiStent group compared with the Xience group. All participants were included in the safety analyses. This trial is registered with ClinicalTrials.gov, number NCT02385279. Between March 20, and Dec 3, 2015, we randomly assigned 1398 patients with 2030 lesions; 703 patients with 1037 lesions were assigned to MiStent, of whom 697 received the index procedure, and 695 patients with 993 lesions were asssigned to Xience, of whom 690 received the index procedure. At 12 months, the primary endpoint had occurred in 40 patients (5·8%) in the sirolimus-eluting stent group and in 45

Predictors of early stent occlusion among plastic biliary stents.

Science.gov (United States)

Khashab, Mouen A; Kim, Katherine; Hutfless, Susan; Lennon, Anne Marie; Kalloo, Anthony N; Singh, Vikesh K

2012-09-01

A major disadvantage of plastic biliary stents is their short patency rates. The aim of this study was to identify predictors of early stent occlusion among patients receiving conventional plastic biliary stents. Early stent occlusion was defined as worsening cholestatic liver test results of a severity sufficiently significant to warrant ERCP with stent exchange prior to the planned stent exchange, or as symptoms of cholangitis. The association of cumulative stent diameter, demographics, stricture location, procedure indication, Charlson comorbidity index, history of prior early stent occlusion, presence of gallbladder, and performance of sphincteromy with the occurrence of early stent occlusion was studied using logistic regression and multivariate analysis. Our patient cohort comprised 343 patients (mean age 59.3 years) who underwent 561 ERCP procedures with the placement of one or more plastic biliary stents (mean number of stents per procedure 1.2, mean total diameter of stents per procedure 12 Fr). Early stent occlusion occurred in 73 (13 %) procedures. Female gender was protective against early stent occlusion (adjusted OR 0.54, 95 % CI 0.32-0.90, p = 0.02), while hilar stricture location was independently associated with a significantly increased risk of early stent occlusion (adjusted OR 3.41, 95 % CI 1.68-6.90, p = 0.0007). Early occlusion of conventional biliary stents occurred in 13 % of cases. While female gender decreased the risk of early stent occlusion, hilar stricture location was a significant predictor of early stent occlusion. Our results suggest that physicians should consider early elective stent exchange in patients with hilar strictures.

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

Science.gov (United States)

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

2014-07-01

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

The risk and prognostic impact of definite stent thrombosis or in-stent restenosis after coronary stent implantation

DEFF Research Database (Denmark)

Thayssen, Per; Jensen, Lisette Okkels; Lassen, Jens Flensted

2012-01-01

Aims: Data are limited on the prognostic impact of stent thrombosis and in-stent restenosis in patients treated with coronary stents. We examined the prognostic impact of stent thrombosis and in-stent restenosis in patients treated with percutaneous coronary intervention (PCI). Methods and results......: All patients who underwent stent implantation from 2002 to 2005 were identified in the Western Denmark Heart Registry. The hazard ratio (HR) for death associated with stent thrombosis or in-stent restenosis was estimated with a Cox regression analysis with stent thrombosis or in-stent restenosis...... as time-dependent variables. A total of 12,277 patients were treated with stent implantation. Stent thrombosis was observed in 111 (0.9%) patients and in-stent restenosis in 503 (4.1%) patients within 12 months after the index PCI. Occurrence of stent thrombosis was associated with an increased risk...

Percutaneous biliary drainage and stenting

International Nuclear Information System (INIS)

Totev, M.

2012-01-01

stents for benign strictures. In cases of malignant obstruction, stents are placed as a palliative measure only if the tumor is unresectable. Various stents are approved for use in the biliary system, including self-expanding and balloon-mounted stents. Tumor ingrowth through the stent, proximal or distal tumor overgrowth, and biliary sludge can cause stent obstruction. Covered stents are now being investigated to overcome the problem of tumor ingrowth. The stent is usually placed at an interval of a few days after percutaneous biliary drainage (PBD), though in cases of uncomplicated percutaneous transhepatic cholangiography (PTC), the stent procedure can be accomplished at the same time. Through our institutional experience and literature overview, we will provide a review outlining the vast array of biliary stenting for both benign and malignant disease. We provided a thorough, concise, and informative review and show that the decompression of the biliary system by drainage or biliary stents is well tolerated by the patients procedure that provide an excellent and minimally invasive palliation, mainly in malignant obstructive jaundice.

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

Science.gov (United States)

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

2016-09-01

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

Therapies targeting inflammation after stent implantation.

Science.gov (United States)

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.

Nasolacrimal Stenting: Toward Improving Outcomes with a Simple Modification of the Song Stent

International Nuclear Information System (INIS)

Lanciego, Carlos; Miguel, Silvia De; Padilla, Manuel; Perea, Miguel; Rodriguez-Merlo, Rufo; Garcia-Garcia, Lorenzo

2006-01-01

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

Comparison of everolimus- and paclitaxel-eluting stents in patients with acute and stable coronary syndromes: pooled results from the SPIRIT (A Clinical Evaluation of the XIENCE V Everolimus Eluting Coronary Stent System) and COMPARE (A Trial of Everolimus-Eluting Stents and Paclitaxel-Eluting Stents for Coronary Revascularization in Daily Practice) Trials.

Science.gov (United States)

Planer, David; Smits, Pieter C; Kereiakes, Dean J; Kedhi, Elvin; Fahy, Martin; Xu, Ke; Serruys, Patrick W; Stone, Gregg W

2011-10-01

This study sought to compare the clinical outcomes of everolimus-eluting stents (EES) versus paclitaxel-eluting stents (PES) in patients with acute coronary syndromes (ACS) and stable coronary artery disease (CAD). Although randomized trials have shown superiority of EES to PES, the safety and efficacy of EES in ACS is unknown. We performed a patient-level pooled analysis from the prospective, randomized SPIRIT (Clinical Evaluation of the XIENCE V Everolimus Eluting Coronary Stent System) II, III, IV, and COMPARE (A Trial of Everolimus-Eluting Stents and Paclitaxel-Eluting Stents for Coronary Revascularization in Daily Practice) trials in which 2,381 patients with ACS and 4,404 patients with stable CAD were randomized to EES or to PES. Kaplan-Meier estimates of death, myocardial infarction (MI), ischemia-driven target lesion revascularization, and stent thrombosis were assessed at 2 years and stratified by clinical presentation (ACS vs. stable CAD). At 2 years, patients with ACS compared with stable CAD had higher rates of death (3.2% vs. 2.4%, hazard ratio [HR]: 1.37 [95% confidence interval (CI): 1.02 to 1.85], p = 0.04) and MI (4.9% vs. 3.4%, HR: 1.45 [95% CI: 1.14 to 1.85], p = 0.02). In patients with ACS, EES versus PES reduced the rate of death or MI (6.6% vs. 9.3%, HR: 0.70 [95% CI: 0.52 to 0.94], p = 0.02), stent thrombosis (0.7% vs. 2.9%, HR: 0.25 [95% CI: 0.12 to 0.52], p = 0.0002), and ischemia-driven target lesion revascularization (4.7% vs. 6.2%, HR: 0.69 [95% CI: 0.48 to 0.99], p = 0.04). In patients with stable CAD, EES reduced the rate of death or MI (4.5% vs. 7.1%, HR: 0.62 [95% CI: 0.48 to 0.80], p = 0.0002), stent thrombosis (0.7% vs. 1.8%, HR: 0.34 [95% CI: 0.19 to 0.62], p = 0.0002), and ischemia-driven target lesion revascularization (3.9% vs. 6.9%, HR: 0.55 [95% CI: 0.42 to 0.73], p SPIRIT II]; NCT00180310; SPIRIT III: A Clinical Evaluation of the Investigational Device XIENCE V Everolimus Eluting Coronary Stent System [EECSS] in the

Indications for stenting during thrombolysis

DEFF Research Database (Denmark)

Bækgaard, N; Broholm, R; Just, Sven Richardt Lundgren

2013-01-01

of a stent in this position is the treatment of choice facilitating the venous flow into an unobstructed outflow tract either from the femoral vein or the deep femoral vein or both. The stent, made of stainless steel or nitinol, has to be self-expandable and flexible with radial force to overcome...... the challenges in this low-pressure system. The characteristics of the anatomy with external compression and often a curved vein segment with diameter difference make stent placement necessary. Ballooning alone has no place in this area. The proportion of inserted stents varies in the published materials...

Long-term results after carotid artery stenting. Restenosis after carotid artery stenting using self-expandable stent

International Nuclear Information System (INIS)

Matsumoto, Yasushi; Furui, Eisuke; Tsuboi, Ken; Takahashi, Akira; Ezura, Masayuki

2008-01-01

Carotid artery stenting has emerged as an acceptable treatment alternative in patients with carotid artery stenosis. Although early clinical results of carotid artery stenting have shown promise, long, term clinical results remain less certain. We report the frequency, management, and clinical results of in-stent restenosis after carotid artery stenting using a self-expandable stent. Between August 1998 and September 2004, 80 carotid artery stenting procedures in 78 patients were performed. We evaluated 76 of the 80 procedures in 75 of the 78 patients treated during this period who had a minimum 6-month clinical and imaging (ultrasound and/or magnetic resonance angiography) follow-up. Recurrent stenosis (≥50%) after carotid artery stenting occurred in 3 (3.9%) patients. The recurrent stenosis occurred within one year after the procedure in all cases. The low rate of in-stent restenosis using self-expandable stent suggested that carotid artery stenting may be an effective alternative treatment for carotid artery stenosis, but more data of long-term follow-up are required. (author)

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

Science.gov (United States)

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

2016-01-01

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

Mechanical Properties of Metallic Stents: How Do These Properties Influence the Choice of Stent for Specific Lesions?

International Nuclear Information System (INIS)

Dyet, John F.; Watts, William G.; Ettles, Duncan F.; Nicholson, Anthony A.

2000-01-01

Purpose: To assess selected balloon-expandable and self-expanding stents for radial force, flexibility, radio-opacity, and trackability, and to relate these physical characteristics to potential indications for placement.Methods: Force-strain curves were plotted for each stent and the force required to produce 50% luminal narrowing was recorded. The ability of the stent to show elastic recoil following deformation was also noted. Flexibility was measured by bending the stents against a force transducer and recording the force required per degree of flexion. Radio-opacity was measured by comparing each stent against a standard aluminum step wedge. Trackability was measured by testing the ability of the stent on its delivery system to track over angles of 90 deg. and 60 deg. Results: The balloon-expandable stents showed greater radial strength and radio-opacity but, apart from the AVE Iliac Bridge stent, showed poorer flexibility and trackability. The self-expanding stents showed less radial force but were able to re-expand following deformity. They were generally more flexible and had better trackability but lower radio-opacity.Conclusion: There is no stent which exhibits all the ideal properties required and therefore the interventionist will need to keep a range of stents available if all lesions are to be addressed

Treatment of Benign and Malignant Tracheobronchial Obstruction with Metal Wire Stents: Experience with a Balloon-Expandable and a Self-Expandable Stent Type

International Nuclear Information System (INIS)

Rieger, Johannes; Hautmann, Hubert; Linsenmaier, Ulrich; Weber, Cristoph; Treitl, Markus; Huber, R.M.; Pfeifer, Klaus-Juergen

2004-01-01

Over the last few years various types of metal wire stents have been increasingly employed in the treatment of both malignant and benign tracheobronchial obstruction. To date, however, few studies have investigated the in vivo properties of different stent types. We implanted 26 balloon-expandable tantalum Strecker stents (18 patients) and 18 self-expandable Wallstents (16 patients) into the tracheobronchial system of 30 patients with combined stenting in 4 patients. Mean age was 51 years (range: 0.5-79 years). Malignant disease was present in 23 patients, benign disease in seven patients. Both patients and individual stents were monitored clinically and radiographically. The probability of stents remaining within the tracheobronchial system, and of their remaining undislocated and uncompressed was calculated using Kaplan-Meier analysis for both stent types. Average stent follow-up time was 112 days until explantation and 115 days until patients' death or discharge. Kaplan-Meier analysis revealed a higher probability for the Wallstent to remain within the tracheobronchial system. Dislocation and compression occurred more rarely. Explantation, however, if desired, was more difficult compared to the Strecker stent. The Wallstent also led to the formation of granulation tissue, especially at the proximal stent end, frequently requiring reintervention. Both stent types proved to be effective therapeutic options in the management of obstructive tracheobronchial disease. The mechanical properties of the Strecker stent seem to be less favorable compared to the Wallstent but removal is easy. For benign disease, however, the Wallstent reveals limitations due to significant side effects

Stent fabric fatigue of grafts supported by Z-stents versus ringed stents: an in vitro buckling test.

Science.gov (United States)

Lin, Jing; Wang, Lu; Guidoin, Robert; Nutley, Mark; Song, Ge; Zhang, Ze; Du, Jia; Douville, Yvan

2014-03-01

Stent-grafts externally fitted with a Z-shaped stents were compared to devices fitted with ringed stents in an in vitro oscillating fatigue machine at 200 cycles per minute and a pressure of 360 mmHg for scheduled durations of up to 1 week. The devices fitted with Z-stents showed a considerably lower endurance limit to buckling compared to the controls. The contact between the apexes of adjacent Z-stents resulted in significant damage to the textile scaffolds and polyester fibers due to the sharp angle of the Z-stents. The ringed stents did not cause any fraying in the textile scaffolds.

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

Science.gov (United States)

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

2012-01-01

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

Drug-eluting stents to prevent stent thrombosis and restenosis.

Science.gov (United States)

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.

Absorbed energy for radiation crosslinking in stabilized PE systems

International Nuclear Information System (INIS)

Novakovic, Lj.; Gal, O.; Charlesby, A.

1990-01-01

A quantitative consideration on the absorbed energy consumption in various γ-irradiated polyethylene systems is given. On the base of the increased gel dose values for the PE systems containing antioxidant, relative to the gel doses for the pure polymers, the surplus of the absorbed energy due to the presence of the particular antioxidant is calculated. The increasing of the energy consumption in the stabilized systems depends on both the type and the content of the basic polymer. The surplus in the absorbed energy decreases with the radiation dose increasing, reflecting both the diminishing of the antioxidant concentration in the irradiating PE systems and the crosslinking level. The findings can be of interest in the estimation of the absorbed doses for the specific radiation crosslinking processes. (author)

Absorbed energy for radiation crosslinking in stabilized PE systems

Energy Technology Data Exchange (ETDEWEB)

Novakovic, Lj; Gal, O [Institut za Nuklearne Nauke Boris Kidric, Belgrade (Yugoslavia); Charlesby, A

1990-01-01

A quantitative consideration on the absorbed energy consumption in various {gamma}-irradiated polyethylene systems is given. On the base of the increased gel dose values for the PE systems containing antioxidant, relative to the gel doses for the pure polymers, the surplus of the absorbed energy due to the presence of the particular antioxidant is calculated. The increasing of the energy consumption in the stabilized systems depends on both the type and the content of the basic polymer. The surplus in the absorbed energy decreases with the radiation dose increasing, reflecting both the diminishing of the antioxidant concentration in the irradiating PE systems and the crosslinking level. The findings can be of interest in the estimation of the absorbed doses for the specific radiation crosslinking processes. (author).

Intravascular ultrasound assessed incomplete stent apposition and stent fracture in stent thrombosis after bare metal versus drug-eluting stent treatment the Nordic Intravascular Ultrasound Study (NIVUS)

DEFF Research Database (Denmark)

Kosonen, Petteri; Vikman, Saila; Jensen, Lisette Okkels

2012-01-01

This prospective multicenter registry used intravascular ultrasound (IVUS) in patients with definite stent thrombosis (ST) to compare rates of incomplete stent apposition (ISA), stent fracture and stent expansion in patients treated with drug-eluting (DES) versus bare metal (BMS) stents. ST...... is a rare, but potential life threatening event after coronary stent implantation. The etiology seems to be multifactorial....

An in Vitro Twist Fatigue Test of Fabric Stent-Grafts Supported by Z-Stents vs. Ringed Stents

Directory of Open Access Journals (Sweden)

Jing Lin

2016-02-01

Full Text Available Whereas buckling can cause type III endoleaks, long-term twisting of a stent-graft was investigated here as a mechanism leading to type V endoleak or endotension. Two experimental device designs supported with Z-stents having strut angles of 35° or 45° were compared to a ringed control under accelerated twisting. Damage to each device was assessed and compared after different durations of twisting, with focus on damage that may allow leakage. Stent-grafts with 35° Z-stents had the most severe distortion and damage to the graft fabric. The 45° Z-stents caused less fabric damage. However, consistent stretching was still seen around the holes for sutures, which attach the stents to the graft fabric. Larger holes may become channels for fluid percolation through the wall. The ringed stent-graft had the least damage observed. Stent apexes with sharp angles appear to be responsible for major damage to the fabrics. Device manufacturers should consider stent apex angle when designing stent-grafts, and ensure their devices are resistant to twisting.

An in Vitro Twist Fatigue Test of Fabric Stent-Grafts Supported by Z-Stents vs. Ringed Stents.

Science.gov (United States)

Lin, Jing; Guidoin, Robert; Du, Jia; Wang, Lu; Douglas, Graeham; Zhu, Danjie; Nutley, Mark; Perron, Lygia; Zhang, Ze; Douville, Yvan

2016-02-16

Whereas buckling can cause type III endoleaks, long-term twisting of a stent-graft was investigated here as a mechanism leading to type V endoleak or endotension. Two experimental device designs supported with Z-stents having strut angles of 35° or 45° were compared to a ringed control under accelerated twisting. Damage to each device was assessed and compared after different durations of twisting, with focus on damage that may allow leakage. Stent-grafts with 35° Z-stents had the most severe distortion and damage to the graft fabric. The 45° Z-stents caused less fabric damage. However, consistent stretching was still seen around the holes for sutures, which attach the stents to the graft fabric. Larger holes may become channels for fluid percolation through the wall. The ringed stent-graft had the least damage observed. Stent apexes with sharp angles appear to be responsible for major damage to the fabrics. Device manufacturers should consider stent apex angle when designing stent-grafts, and ensure their devices are resistant to twisting.

Stent

Science.gov (United States)

... Drugs & Supplements Videos & Tools Español You Are Here: Home → Medical Encyclopedia → Stent URL of this page: //medlineplus.gov/ency/article/002303.htm Stent To use the sharing features on this page, please enable JavaScript. A stent is a tiny tube placed into a hollow structure in your ...

Symptomatic stent cast.

LENUS (Irish Health Repository)

Keohane, John

2012-02-03

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.

Primary and revision efficacy of cross-wired metallic stents for endoscopic bilateral stent-in-stent placement in malignant hilar biliary strictures.

Science.gov (United States)

Lee, T H; Moon, J H; Kim, J H; Park, D H; Lee, S S; Choi, H J; Cho, Y D; Park, S H; Kim, S J

2013-01-01

Endoscopic bilateral drainage for inoperable malignant hilar biliary strictures (HBS) using metal stents is considered to be technically difficult. Furthermore, endoscopic revision of bilateral stenting after occlusion can be challenging. This study was performed to evaluate the long-term efficacy of endoscopic bilateral stent-in-stent placement of cross-wired metallic stents in high-grade malignant HBS and planned endoscopic bilateral revision. A total of 84 patients with inoperable high-grade malignant HBS were enrolled from three academic tertiary referral centers. Two cross-wired metal stents were inserted using a bilateral stent-in-stent placement method. Bilateral endoscopic revision was also performed during follow-up using either identical metal stents or plastic stents. The main outcome measurements were technical and functional success, complications, stent patency, and endoscopic revision efficacy. The technical and clinical success rates of endoscopic bilateral stent-in-stent placement of cross-wired metallic stents were 95.2% (80/84) and 92.9% (78/84), respectively. Median patency (range) and survival were 238 days (10-429) and 256 days (10-1130), respectively. Obstruction of primary bilateral stents occurred in 30.8% (24/78) of patients with functionally successful stent placement. The technical and clinical success rates of planned bilateral endoscopic revision for occluded stents were 83.3% (20/24) and 79.2% (19/24), respectively. For revision, bilateral metallic stents were placed in 11 patients (55.0%); the remaining patients received plastic stents. Palliative endoscopic bilateral stent-in-stent placement of cross-wired metallic stents was effective in patients with inoperable HBS. Revision endoscopic bilateral stenting may be feasible and successful in cases where the primary deployed metal stents are occluded. © Georg Thieme Verlag KG Stuttgart · New York.

[Technical feasibility of the implantation of a monorail stent system into the renal arteries without pre-dilatation].

Science.gov (United States)

Neumann, C; Gschwendtner, M; Karnel, F; Mair, J; Dorffner, G; Dorffner, R

2005-01-01

To evaluate the technical feasibility of the implantation of the monorail RX Herculink system into the renal arteries without pre-dilatation. Forty-two patients (mean age 71 years) from four centers with a total of 44 renal artery stenoses underwent implantation of the RX Herculink stent. The mean grade of the stenosis was 83.8 %, the mean length 7.5 mm. The stenoses were ostial in 38 cases and in immediate proximity to the ostium in 6 cases. The mean follow-up-period was 57 weeks (24 - 176 weeks). In 42 cases, the implantation was successful without pre-dilatation. In 2 cases, pre-dilatation was carried out. In none of the cases, detachment of the stent from the balloon was observed. In one stenosis with a length of 17 mm, implantation of two stents was performed. In 9 cases, post-dilatation with a larger balloon or higher balloon pressure was necessary. Residual stenoses exceeding 30 % were not observed. Two patients developed local bleeding at the puncture site. During the follow-up, restenoses were observed in 5 stents after 26 to 126 weeks, which necessitated a second intervention in 3 cases (PTA in 2 cases, re-stenting in 1 case). The primary patency rate after 6 and 12 months was 0.92 +/- 0.056 according to Kaplan-Meier, the secondary patency rate after 6 and 12 months was 1.0 +/- 0.0. Implantation of the RX Herculink stent system into the renal arteries without pre-dilatation is technically feasible and safe. Even without pre-dilatation, the stent-system can be advanced through the stenosis without detachment. The complication rate is low. Our clinical results are comparable to previous studies.

Delayed thrombosis or stenosis following enterprise-assisted stent-coiling: is it safe? Midterm results of the interstate collaboration of enterprise stent coiling.

Science.gov (United States)

Mocco, J; Fargen, Kyle M; Albuquerque, Felipe C; Bendok, Bernard R; Boulos, Alan S; Carpenter, Jeffrey S; Fiorella, David J; Hoh, Brian L; Howington, Jay U; Liebman, Kenneth M; Natarajan, Sabareesh K; Rai, Ansaar T; Rodriguez-Mercado, Rafael; Siddiqui, Adnan H; Snyder, Kenneth V; Veznedaroglu, Erol; Hopkins, L Nelson; Levy, Elad I

2011-10-01

Stent-assisted coiling of intracranial aneurysms with self-expanding stents has widened the applicability of neuroendovascular therapies to those aneurysms previously considered "uncoilable" because of poor morphology. The Enterprise Vascular Reconstruction Device and Delivery System (Cordis) has demonstrated promising initial short-term results. However, the rates of delayed in-stent stenosis or thrombosis are not known. To report midterm results of the Enterprise stent system. A 10-center registry was created to provide a large volume of data on the safety and efficacy of the Enterprise stent system. Pooled data were compiled for consecutive patients undergoing Enterprise stent-assisted coiling at each institution. Available follow-up data were evaluated for the incidence of in-stent stenosis, thrombosis, and aneurysm occlusion. In total, 213 patients (176 females) with 219 aneurysms were treated with the Enterprise stent. One hundred ten patients had undergone delayed angiography (≥ 30 days from stent placement, mean follow-up 174.6 days). Forty percent of patients demonstrated total occlusion with 88% having ≥ 90% aneurysm occlusion. Six percent of patients had delayed (>30 days) angiographic findings, of which 3% demonstrated significant (≥ 50%) in-stent stenosis or occlusion. Seven delayed thrombotic events occurred (3%), along with 2 additional immediate periprocedural events. All 7 delayed events were concomitant to cessation of double-antiplatelet therapy. Midterm occlusion rates are excellent, and stenosis and thrombosis rates are comparable to other available neurovascular stents. Interruption of antiplatelet therapy appears to be a factor in those developing delayed stenosis or thrombosis.

Comparative technical-economical analysis of solar systems with liquid absorbent

International Nuclear Information System (INIS)

Kaloyanov, N.; Popova, I.

2005-01-01

An analyses of solar water heating systems with two types liquid absorbent is presented. A system with classic collector design is used for comparison. The dependence between the value of the collectors active area and the absorbent type, collectors slope and design parameters is discussed. Two economic indexes (payback period and index of actual net value, based on the electricity price) are used for comparison of the different variants of the system. The presented results shown that: 1) the payback period can be reduced twice if the collectors with liquid absorbent are used; 2) the index of actual net value of the systems using the collectors with fluid absorbent is about four times higher than this one with classic collectors; 3) the systems using distilled water like a liquid absorbent can not fulfil the requirements for the positive economic indicators

TOKYO criteria 2014 for transpapillary biliary stenting.

Science.gov (United States)

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

2015-01-01

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

Circumferential Stent Fracture: Novel Detection and Treatment with the Use of StentBoost

OpenAIRE

Ramegowda, Raghu T.; Chikkaswamy, Srinivas B.; Bharatha, Ashalatha; Radhakrishna, Jayashree; Krishnanaik, Geetha B.; Nanjappa, Manjunath C.; Panneerselvam, Arunkumar

2012-01-01

Circumferential stent fracture is extremely uncommon, and in rare cases, it can cause stent thrombosis. Recognizing stent fracture can be difficult on conventional fluoroscopy because of poor stent radiopacity. We found that StentBoost image acquisition yields improved visibility of stent struts, enabling the identification of stent fracture and the precise positioning of new stents over previously stented segments.

Metallic ureteral stents in malignant ureteral obstruction: clinical factors predicting stent failure.

Science.gov (United States)

Chow, Po-Ming; Hsu, Jui-Shan; Huang, Chao-Yuan; Wang, Shuo-Meng; Lee, Yuan-Ju; Huang, Kuo-How; Yu, Hong-Jheng; Pu, Yeong-Shiau; Liang, Po-Chin

2014-06-01

To provide clinical outcomes of the Resonance metallic ureteral stent in patients with malignant ureteral obstruction, as well as clinical factors predicting stent failure. Cancer patients who have received Resonance stents from July 2009 to March 2012 for ureteral obstruction were included for chart review. Stent failure was detected by clinical symptoms, image studies, and renal function tests. Survival analysis for stent duration was used to estimate patency rate and factors predicting stent failure. A total of 117 stents were inserted successfully into 94 ureteral units in 79 patients. There were no major complications. These stents underwent survival analysis and proportional hazard regression. The median duration for the stents was 5.77 months. In multivariate analysis, age (P=0.043), preoperative serum creatinine level (P=0.0174), and cancer type (P=0.0494) were significant factors associated with stent failure. Cancer treatment before and after stent insertion had no effect on stent duration. Resonance stents are effective and safe in relieving malignant ureteral obstructions. Old age and high serum creatinine level are predictors for stent failure. Stents in patients with lower gastrointestinal cancers have longer functional duration.

The Effect of Stent Cell Geometry on Carotid Stenting Outcomes

Energy Technology Data Exchange (ETDEWEB)

Alparslan, Burcu, E-mail: burcu.alparslan@gmail.com [Yozgat State Hospital, Radiology Clinic (Turkey); Nas, Omer Fatih, E-mail: omerfatihnas@gmail.com [Uludag University Faculty of Medicine, Department of Radiology (Turkey); Eritmen, Ulku Turpcu, E-mail: drulkutur@hotmail.com.tr [Special Eregli Anatolia Hospital, Radiology Clinic (Turkey); Duran, Selcen, E-mail: selcenduran16@hotmail.com [Yerkoy State Hospital, Neurology Clinic (Turkey); Ozkaya, Guven, E-mail: ozkaya@uludag.edu.tr [Uludag University Faculty of Medicine, Department of Biostatistics (Turkey); Hakyemez, Bahattin, E-mail: bhakyemez@uludag.edu.tr [Uludag University Faculty of Medicine, Department of Radiology (Turkey)

2016-04-15

PurposeThe aim of this study was to investigate the effect of stent cell geometry on midterm results of carotid artery stenting (CAS).Materials and MethodOne hundred fifty-five patients underwent CAS between February 2010 and December 2012. Ninety-one open- and 84 closed-cell stents were used in this non-randomized, retrospective study. Periprocedural complications were defined as the ones happened during the procedure or within 30 days afterwards. Starting from the 6th month after the procedure, in-stent restenosis was detected with multidetector computed tomography angiography and classified into four groups from focal restenosis to occlusion.ResultsEleven complications were encountered in the periprocedural period (four on the open- and seven on the closed-cell group). Total complication rate was 6.3 % (11/175). No significant difference was detected in terms of periprocedural complications between two groups (p = 0.643). There was statistically significant difference between stent design groups in regard to radiological findings (p = 0.002). Sixteen of open-cell stents and three of closed-cell stents had focal restenosis. One closed-cell stent had diffuse proliferative restenosis and one open-cell stent had total occlusion.ConclusionIn-stent restenosis was more common in open-cell stent group, which have larger free cell area than closed-cell stents. Although our radiologic findings promote us to use closed-cell design if ‘possible’, no difference was detected in terms of clinical outcomes.

Radial force measurement of endovascular stents: Influence of stent design and diameter.

Science.gov (United States)

Matsumoto, Takuya; Matsubara, Yutaka; Aoyagi, Yukihiko; Matsuda, Daisuke; Okadome, Jun; Morisaki, Koichi; Inoue, Kentarou; Tanaka, Shinichi; Ohkusa, Tomoko; Maehara, Yoshihiko

2016-04-01

Angioplasty and endovascular stent placement is used in case to rescue the coverage of main branches to supply blood to brain from aortic arch in thoracic endovascular aortic repair. This study assessed mechanical properties, especially differences in radial force, of different endovascular and thoracic stents. We analyzed the radial force of three stent models (Epic, E-Luminexx and SMART) stents using radial force-tester method in single or overlapping conditions. We also analyzed radial force in three thoracic stents using Mylar film testing method: conformable Gore-TAG, Relay, and Valiant Thoracic Stent Graft. Overlapping SMART stents had greater radial force than overlapping Epic or Luminexx stents (P stents was greater than that of all three endovascular stents (P stents, site of deployment, and layer characteristics. In clinical settings, an understanding of the mechanical characteristics, including radial force, is important in choosing a stent for each patient. © The Author(s) 2015.

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

Science.gov (United States)

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

2013-02-01

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

Predictors of stent dysfunction after self-expandable metal stent placement for malignant gastric outlet obstruction: tumor ingrowth in uncovered stents and migration of covered stents.

Science.gov (United States)

Hori, Yasuki; Naitoh, Itaru; Hayashi, Kazuki; Ban, Tesshin; Natsume, Makoto; Okumura, Fumihiro; Nakazawa, Takahiro; Takada, Hiroki; Hirano, Atsuyuki; Jinno, Naruomi; Togawa, Shozo; Ando, Tomoaki; Kataoka, Hiromi; Joh, Takashi

2017-10-01

Endoscopic metallic stenting is widely accepted as a palliation therapy for malignant gastric outlet obstruction (GOO). However, the predictors of stent dysfunction have not been clarified. We aimed to evaluate the predictors, especially tumor ingrowth in uncovered self-expandable metallic stents (U-SEMS) and migration of covered self-expandable metallic stents (C-SEMS), which are the main causes related to the stent characteristics. In this multicenter retrospective study, we compared patients with U-SEMS and C-SEMS in terms of clinical outcomes, and predictors of stent dysfunction. In total, 252 patients (126 with U-SEMS and 126 with C-SEMS) were enrolled. There were no significant differences in technical success, clinical success, GOO score, or time to stent dysfunction. Tumor ingrowth was significantly more frequent in U-SEMS (U-SEMS, 11.90% vs. C-SEMS, 0.79%; p = 0.002), and stent migration was significantly more frequent for C-SEMS (C-SEMS, 8.73% vs. U-SEMS, 0.79%; p = 0.005). Karnofsky performance status (p = 0.04), no presence of ascites (p = 0.02), and insufficient (stent expansion (p = 0.003) were significantly associated with tumor ingrowth in U-SEMS. Meanwhile, a shorter stent length (p = 0.05) and chemotherapy (p = 0.03) were predictors of C-SEMS migration. Both U-SEMS and C-SEMS are effective with comparable patencies. Tumor ingrowth and stent migration are the main causes of stent dysfunction for U-SEMS and C-SEMS, respectively. With regard to stent dysfunction, U-SEMS might be a good option for patients receiving chemotherapy, while C-SEMS with longer stents for patients in good condition. (Clinical trial registration number: UMIN000024059).

Airway stents

Science.gov (United States)

Keyes, Colleen

2018-01-01

Stents and tubes to maintain the patency of the airways are commonly used for malignant obstruction and are occasionally employed in benign disease. Malignant airway obstruction usually results from direct involvement of bronchogenic carcinoma, or by extension of carcinomas occurring in the esophagus or the thyroid. External compression from lymph nodes or metastatic disease from other organs can also cause central airway obstruction. Most malignant airway lesions are surgically inoperable due to advanced disease stage and require multimodality palliation, including stent placement. As with any other medical device, stents have significantly evolved over the last 50 years and deserve an in-depth understanding of their true capabilities and complications. Not every silicone stent is created equal and the same holds for metallic stents. Herein, we present an overview of the topic as well as some of the more practical and controversial issues surrounding airway stents. We also try to dispel the myths surrounding stent removal and their supposed use only in central airways. At the end, we come to the long-held conclusion that stents should not be used as first line treatment of choice, but after ruling out the possibility of curative surgical resection or repair. PMID:29707506

Technical feasibility of the implantation of a monorail stent system into the renal arteries without pre-dilatation

International Nuclear Information System (INIS)

Neumann, C.; Dorffner, R.; Gschwendtner, M.; Karnel, F.; Mair, J.; Dorffner, G.

2005-01-01

Purpose: to evaluate the technical feasibility of the implantation of the monorail RX Herculink trademark system into the renal arteries without pre-dilatation. Materials and methods: forty-two patients (mean age 71 years) from four centers with a total of 44 renal artery stenoses underwent implantation of the RX Herculink trademark stent. The mean grade of the stenosis was 83.8%, the mean length 7.5 mm. The stenoses were ostial in 38 cases and in immediate proximity to the ostium in 6 cases. The mean follow-up-period was 57 weeks (24 - 176 weeks). Results: in 42 cases, the implantation was successful without pre-dilatation. In 2 cases, pre-dilatation was carried out. In none of the cases, detachment of the stent from the balloon was observed. In one stenosis with a length of 17 mm, implantation of two stents was performed. In 9 cases, post-dilatation with a larger balloon or higher balloon pressure was necessary. Residual stenoses exceeding 30% were not observed. Two patients developed local bleeding at the puncture site. During the follow-up, restenoses were observed in 5 stents after 26 to 126 weeks, which necessitated a second intervention in 3 cases (PTA in 2 cases, re-stenting in 1 case). The primary patency rate after 6 and 12 months was 0.92 ± 0.056 according to Kaplan-Meier, the secondary patency rate after 6 and 12 months was 1.0 ± 0.0. Conclusion: implantation of the RX Herculink trademark stent system into the renal arteries without pre-dilatation is technically feasible and safe. Even without pre-dilatation, the stent-system can be advanced through the stenosis without detachment. The complication rate is low. Our clinical results are comparable to previous studies. (orig.)

Recurrence of Subacute Stent Thrombosis and In-Stent Restenosis during Five Months after Stent Implantation in the LAD. A Case Report.

OpenAIRE

島田, 弘英; 大和, 眞史; 櫻井, 俊平; 疋田, 博之; 池田, 修一

2001-01-01

A coronary stent was deployed in the left anterior descending artery of an 82-year-old woman with unstable angina.Recurrence of subacute stent thrombosis and in-stent restenosis occurred frequently during the five months after initial stent implantation.Balloon angioplasty and cutting balloon angioplasty failed to prevent these complications,but they ceased after re-stenting in the initial stent.In this case,tissue protrusion through the stent strut, deformation of the coil stent and inadequa...

Lean manufacturing and Toyota Production System terminology applied to the procurement of vascular stents in interventional radiology.

Science.gov (United States)

de Bucourt, Maximilian; Busse, Reinhard; Güttler, Felix; Wintzer, Christian; Collettini, Federico; Kloeters, Christian; Hamm, Bernd; Teichgräber, Ulf K

2011-08-01

OBJECTIVES: To apply the economic terminology of lean manufacturing and the Toyota Production System to the procurement of vascular stents in interventional radiology. METHODS: The economic- and process-driven terminology of lean manufacturing and the Toyota Production System is first presented, including information and product flow as well as value stream mapping (VSM), and then applied to an interdisciplinary setting of physicians, nurses and technicians from different medical departments to identify wastes in the process of endovascular stent procurement in interventional radiology. RESULTS: Using the so-called seven wastes approach of the Toyota Production System (waste of overproducing, waiting, transport, processing, inventory, motion and waste of defects and spoilage) as well as further waste characteristics (gross waste, process and method waste, and micro waste), wastes in the process of endovascular stent procurement in interventional radiology were identified and eliminated to create an overall smoother process from the procurement as well as from the medical perspective. CONCLUSION: Economic terminology of lean manufacturing and the Toyota Production System, especially VSM, can be used to visualise and better understand processes in the procurement of vascular stents in interventional radiology from an economic point of view.

An easier method for performing a pancreaticojejunostomy for the soft pancreas using a fast-absorbable suture

OpenAIRE

Hakamada, Kenichi; Narumi, Shunji; Toyoki, Yoshikazu; Nara, Masaki; Ishido, Kenosuke; Miura, Takuya; Kubo, Norihito; Sasaki, Mutsuo

2008-01-01

AIM: To clarify the usefulness of a new method for performing a pancreaticojejunostomy by using a fast-absorbable suture material irradiated polyglactin 910, and a temporary stent tube for a narrow pancreatic duct with a soft pancreatic texture.

StentBoost Visualization for the Evaluation of Coronary Stent Expansion During Percutaneous Coronary Interventions

OpenAIRE

Cura, Fernando; Albertal, Mariano; Candiello, Alfonsina; Nau, Gerardo; Bonvini, Victor; Tricherri, Hernan; Padilla, Lucio T.; Belardi, Jorge A.

2013-01-01

Introduction Inadequate stent implantation is associated with stent thrombosis and restenosis. StentBoost can enhance stent visualization and evaluate stent expansion. Currently, there are limited comparison studies between StentBoost and intravascular ultrasound (IVUS). We aimed to test the correlation and agreement between IVUS and StentBoost measurements. Methods From December 2010 to December 2011, 38 patients (54 stents) were analyzed using IVUS and StentBoost. Minimal stent diameter and...

Stent malapposition, as a potential mechanism of very late stent thrombosis after bare-metal stent implantation: A case report

Energy Technology Data Exchange (ETDEWEB)

Higuma, Takumi, E-mail: higuma@cc.hirosaki-u.ac.jp; Abe, Naoki; Hanada, Kenji; Yokoyama, Hiroaki; Tomita, Hirofumi; Okumura, Ken

2014-04-15

A 90-year-old man was admitted to our hospital with acute ST-segment elevation myocardial infarction. He had a history of post-infarction angina pectoris 79 months ago and had a bare-metal stent (BMS) implanted in the proximal left anterior descending artery at our hospital. Emergent coronary angiography demonstrated thrombotic occlusion in the previously stented segment. After catheter thrombectomy, antegrade flow was restored, but 90% stenosis with haziness persisted in the proximal and distal portions of the previously stented segment. Intravascular ultrasound imaging showed interstrut cavities or stent malapposition at the proximal and distal sites of stented segment. In close proximity to the sites, residual thrombi were also observed. Optical coherence tomography (OCT) demonstrated neither lipid-laden neointimal tissue nor rupture but clearly demonstrated residual thrombus adjacent to the malapposed region in addition to the stent malapposition. PCI with balloon was successfully performed and stent apposition was confirmed by OCT. Stent malapposition is an unusual mechanism of very late stent thrombosis after BMS implantation. OCT can clearly reveal the etiology of stent thrombosis.

The SYNERGY biodegradable polymer everolimus eluting coronary stent: Porcine vascular compatibility and polymer safety study.

Science.gov (United States)

Wilson, Gregory J; Marks, Angela; Berg, Kimberly J; Eppihimer, Michael; Sushkova, Natalia; Hawley, Steve P; Robertson, Kimberly A; Knapp, David; Pennington, Douglas E; Chen, Yen-Lane; Foss, Aaron; Huibregtse, Barbara; Dawkins, Keith D

2015-11-15

SYNERGY is a novel platinum chromium alloy stent that delivers abluminal everolimus from an ultrathin poly-lactide-co-glycide (PLGA) biodegradable polymer. This study evaluated the in vivo degradation of the polymer coating, everolimus release time course, and vascular compatibility of the SYNERGY stent. SYNERGY stents were implanted in arteries of domestic swine. Devices were explanted at predetermined time points (up to 120 days) and the extent of PLGA coating or everolimus remaining on the stents was quantified. Everolimus levels in the arterial tissue were also evaluated. A pathological analysis on coronary arteries of single and overlapping stents was performed at time points between 5 and 270 days. PLGA bioabsorption began immediately after implantation, and drug release was essentially complete by 90 days; PLGA absorption was substantially complete by 120 days (>90% of polymer was absorbed) leaving a bare metal SYNERGY stent. Vascular response was similar among SYNERGY and control stents (bare metal, polymer-only, and 3× polymer-only). Mild increases in para-strut fibrin were seen for SYNERGY at an early time point with no significant differences in all other morphological and morphometric parameters through 270 days or endothelial function (eNOS immunostaining) at 90 or 180 days. Inflammation was predominantly minimal to mild for all device types. In a swine model, everolimus was released by 90 days and PLGA bioabsorption was complete shortly thereafter. The SYNERGY stent and its biodegradable polymer, even at a 3× safety margin, demonstrated vascular compatibility similar to bare metal stent controls. © 2015 Wiley Periodicals, Inc.

Incidence of definite stent thrombosis or in-stent restenosis after drug-eluting stent implantation for treatment of coronary in-stent restenosis. From western denmark heart registry

DEFF Research Database (Denmark)

Jensen, Jesper; Jensen, Lisette Okkels; Terkelsen, Christian Juhl

2012-01-01

There are limited data on the optimal management of in-stent restenosis after percutaneous coronary intervention (PCI) with bare metal stent (BMS) or drug-eluting stent (DES) implantations. We assessed the clinical presentation, the incidence, and prognosis of definite stent thrombosis...

The management of unimplantable stent during endovascular procedure:report of three cases

International Nuclear Information System (INIS)

Xiong Jiang; Wang Lijun; Guo Wei; Liu Xiaoping; Yin Tai; Jia Xin; Ma Xiaohui; Liu Meng; Zhang Hongpeng; Zhang Minhong

2010-01-01

Objective: To summarize the experience of dealing with the difficulty of the stent implantation encountered in the endovascular procedure. Methods: The causes of unimplantable stent encountered in the endovascular procedure included the delivery system entraping due to the stenosis and shrinking of peripheral self-expandable stent, the balloon expandable stent implantation and retrievement failure due to the rupture-balloon or stent edge opening, and the delivery system entraping due to aortic stent graft for aorta kinking. The balloon dilation for the stenosis and shrinking stent, the large caliber introducer sheath for removal of the rupture-balloon and edge opening, the expandable stent and balloon-assisted delivery system retrieve were used to solve the above three dilemma of unimplantable stent occurred in the endovascular procedure. Results: These three dilemma of stent unimplantable problem in the endovascular therapy were solved by endovascular method while little additional incision injury was added to the patients. Conclusion: For solving stent unimplantable problem the endovascular technique is the method of first choice, nevertherless, it is very important for the operator to be highly skilled in manipulating endovascular procedure. (authors)

Risk of stent thrombosis among bare-metal stents, first-generation drug-eluting stents, and second-generation drug-eluting stents: results from a registry of 18,334 patients.

Science.gov (United States)

Tada, Tomohisa; Byrne, Robert A; Simunovic, Iva; King, Lamin A; Cassese, Salvatore; Joner, Michael; Fusaro, Massimiliano; Schneider, Simon; Schulz, Stefanie; Ibrahim, Tareq; Ott, Ilka; Massberg, Steffen; Laugwitz, Karl-Ludwig; Kastrati, Adnan

2013-12-01

This study sought to compare the risk of stent thrombosis among patients treated with bare-metal stents (BMS), first-generation drug-eluting stents (G1-DES), and second-generation drug-eluting stents (G2-DES) for a period of 3 years. In patients undergoing coronary stenting, there is a scarcity of long-term follow-up data on cohorts large enough to compare rates of stent thrombosis across the stent generations. A total of 18,334 patients undergoing successful coronary stent implantation from 1998 to 2011 at 2 centers in Munich, Germany, were included in this study. Patients were stratified into 3 groups according to treatment with BMS, G1-DES, and G2-DES. The cumulative incidence of definite stent thrombosis at 3 years was 1.5% with BMS, 2.2% with G1-DES, and 1.0% with G2-DES. On multivariate analysis, G1-DES compared with BMS showed a significantly higher risk of stent thrombosis (odds ratio [OR]: 2.05; 95% confidence interval [CI]: 1.47 to 2.86; p stent thrombosis compared with BMS (OR: 0.82; 95% CI: 0.56 to 1.19; p = 0.30). Beyond 1 year, the risk of stent thrombosis was significantly increased with G1-DES compared with BMS (OR: 4.72; 95% CI: 2.01 to 11.1; p stenting, compared with BMS, there was a significant excess risk of stent thrombosis at 3 years with G1-DES, driven by an increased risk of stent thrombosis events beyond 1 year. G2-DES were associated with a similar risk of stent thrombosis compared with BMS. Copyright © 2013 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Emergency and elective implantation of covered stent systems in iatrogenic arterial injuries

International Nuclear Information System (INIS)

Goltz, J.P.; Kickuth, R.; Bastuerk, P.; Hoppe, H.; Triller, J.

2011-01-01

Purpose: To evaluate the effectiveness and safety of covered stents for the management of iatrogenic arterial injury. Materials and Methods: Between 03/1998 and 12/2009, 31 patients underwent selective covered stent implantation after iatrogenic arterial injury. 12/31 of these patients (38.7 %) were hemodynamically unstable. Six different endovascular covered stent types were utilized. The primary endpoints of this study were technical and clinical success and rates of minor and major complications. Results: Initial angiograms demonstrated active extravasation in 19 (61.3 %) patients and pseudoaneurysms in 12 (38.7 %) patients. The following sites of bleeding origin were detected: axillary artery, subclavian artery, common iliac artery, external iliac artery, internal iliac artery, common femoral artery, superficial femoral artery, popliteal and fibular artery, femoro-popliteal and popliteo-crural bypasses, common hepatic artery, aberrant hepatic artery, cystic and gastroduodenal artery. In all patients bleeding was effectively controlled by covered stent implantation resulting in an immediate technical success of 100 %. Clinical success attributed to covered stent implantation was documented in 30 of the 31 patients (96.8 %). Major complications included death in four patients (11.1 %), acute thrombosis with arm ischemia in one patient (2.8 %) and stent fracture with associated pseudoaneurysm in another patient (2.8 %). In 2/31 patients (6.5 %) covered stent failure was detected and successfully treated by implantation of a second covered stent. Conclusion: Emergency and elective implantation of covered stents may be used for minimally invasive and effective management of iatrogenic arterial injury. (orig.)

Application and biocompatibility of a new absorbable magnesium alloy stent in blood vessels%新型可吸收镁合金支架在血管内应用及生物相容性

Institute of Scientific and Technical Information of China (English)

赵辉; 雷民

2016-01-01

BACKGROUND: In vivo animal experiments have found that magnesium al oy stents can be completely degraded in a slow, orderly and non-toxic manner fol owing the vascular remodeling. OBJECTIVE: To investigate the applied effect and biocompatibility of a new type of magnesium al oy stent in blood vessels. METHODS: Forty-two crossbreed dogs were implanted with absorbable magnesium al oy stents via the coronary artery or left femoral artery. At days 1, 3, 5 and weeks 1, 2, 3, 4 after implantation, coronary or femoral artery angiography, inflammatory factor detection and morphological analysis targeting intimal hyperplasia were performed. RESULTS AND CONCLUSION: At 1 day after implantation, the stents had the complete shape and were ful y extended; at 3 days after implantation, the stents were degraded partial y; at 1 week after implantation, the stents were degraded completely. Within 1-3 weeks after implantation, the levels of tumor necrosis factor α, interleukin-6 and interleukin-8 continued to decrease. At 2 and 3 weeks after implantation, the target vessels presented with mild intimal hyperplasia. As time went on, the hyperplasia area increased gradual y, and the percentage of intimal hyperplasia increased gradual y. Blood magnesium concentration remained unchanged before and after stent implantation. The results show that the new absorbable magnesium al oy stent can be completely degraded within 1 week after stent implantation and has good biocompatibility.%背景：动物体内实验发现，可吸收镁合金支架随着血管结构重塑的完成，可通过缓慢、有序、无毒害降解方式在体内完全降解。目的：探讨新型血管内可吸收镁合金支架在血管内的应用效果及生物相容性。方法：取42只防疫杂种犬，均于冠状动脉或者左侧股动脉置入可吸收镁合金支架，置入后1 d、3 d、5 d、1周、2周、3周、4�

Removal of retrievable self-expandable urethral stents: experience in 58 stents

International Nuclear Information System (INIS)

Shin, Ji Hoon; Song, Ho-Young; Kim, Jin Hyoung; Ko, Heung-Kyu; Kim, Yong Jae; Woo, Chul-Woong; Kim, Tae-Hyung; Ko, Gi-Young; Yoon, Hyun-Ki; Sung, Kyu-Bo; Park, Hyungkeun

2006-01-01

The purpose of this study was to retrospectively evaluate the safety and efficacy of removing retrievable self-expandable urethral stents using a retrieval hook wire. Under fluoroscopic guidance, the removal of 58 polyurethane or PTFE (polytetrafluoroethylene)-covered stents was attempted in 33 patients using a retrieval hook wire. Indications for removal were elective removal (n=21), stent migration (n=19), formation of tissue hyperplasia around or inside of the stent (n=14), stent deformity (n=3), and severe pain (n=1). The mean time the stents remained in place was 64.8±42.9 days (range, 1-177 days). Fifty-six (97%) of the 58 stents were successfully removed using the retrieval hook wire despite the following difficulties; hook wire disconnection (n=2), untied drawstrings (n=3), and polyurethane membrane disruption/separation (n=4). The removal procedure using a retrieval hook wire failed in two stents (3%) which had migrated into the urinary bladder. One of the two stents with migration into the urinary bladder was removed using a snare through the cystostomy route. The overall complication rate was 14% (seven hematuria cases and one urethral tear case), and all were minor and spontaneously resolved without further treatment. In conclusion, removal of retrievable urethral stents using a retrieval hook wire was safe and effective despite some technical difficulties. It is a useful method for allowing temporary stent placement and solving various complications of stent use. (orig.)

Removal of retrievable self-expandable urethral stents: experience in 58 stents

Energy Technology Data Exchange (ETDEWEB)

Shin, Ji Hoon; Song, Ho-Young; Kim, Jin Hyoung; Ko, Heung-Kyu; Kim, Yong Jae; Woo, Chul-Woong; Kim, Tae-Hyung; Ko, Gi-Young; Yoon, Hyun-Ki; Sung, Kyu-Bo [Asan Medical Center, Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Seoul (Korea); Park, Hyungkeun [Asan Medical Center, Department of Urology, University of Ulsan College of Medicine, Seoul (Korea)

2006-09-15

The purpose of this study was to retrospectively evaluate the safety and efficacy of removing retrievable self-expandable urethral stents using a retrieval hook wire. Under fluoroscopic guidance, the removal of 58 polyurethane or PTFE (polytetrafluoroethylene)-covered stents was attempted in 33 patients using a retrieval hook wire. Indications for removal were elective removal (n=21), stent migration (n=19), formation of tissue hyperplasia around or inside of the stent (n=14), stent deformity (n=3), and severe pain (n=1). The mean time the stents remained in place was 64.8{+-}42.9 days (range, 1-177 days). Fifty-six (97%) of the 58 stents were successfully removed using the retrieval hook wire despite the following difficulties; hook wire disconnection (n=2), untied drawstrings (n=3), and polyurethane membrane disruption/separation (n=4). The removal procedure using a retrieval hook wire failed in two stents (3%) which had migrated into the urinary bladder. One of the two stents with migration into the urinary bladder was removed using a snare through the cystostomy route. The overall complication rate was 14% (seven hematuria cases and one urethral tear case), and all were minor and spontaneously resolved without further treatment. In conclusion, removal of retrievable urethral stents using a retrieval hook wire was safe and effective despite some technical difficulties. It is a useful method for allowing temporary stent placement and solving various complications of stent use. (orig.)

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

Science.gov (United States)

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

2016-12-01

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

Self-Expandable Metal Stents and Trans-stent Light Delivery: Are Metal Stents and Photodynamic Therapy Compatible?

Science.gov (United States)

Wang, Luo-Wei; Li, Li-Bo; Li, Zhao-Shen; Chen, Yang K; Hetzel, Fred W.; Huang, Zheng

2008-01-01

Background and Objectives: Obstructive non-small cell lung cancer and obstructive esophageal cancer are US FDA approved indications of photodynamic therapy (PDT). The usefulness of PDT for the treatment of cholangiocarcinoma is currently under clinical investigation. Endoscopic stenting for lumen restoration is a common palliative intervention for those indications. It is important to assess whether self-expandable metal stents are compatible with trans-stent PDT light delivery. Study Design/Materials and Methods: Direct effects of various components of metal biliary (n = 2), esophageal (n = 2), and bronchial (n = 1) stents on PDT light transmittance and distribution were examined using a point or linear light source (630 or 652 nm diode laser). Resected pig biliary duct and esophageal wall tissues were used to examine the feasibility of PDT light delivery through the fully expanded metal stents. Results: While using a point light source, the metal components (thread and joint) of the stent could cause a significant shadow effect. The liner material (polytetrafluoroethylene or polyurethane) could cause various degrees of light absorption. When the stent was covered with a thin layer of biliary duct and esophageal tissues containing all wall layers, the shadow effect could be mitigated due to tissue scattering. Conclusions: This study clearly demonstrates that it is feasible to combine stenting and PDT for the treatment of luminal lesions. PDT light dose should be adjusted to counteract the reduction of light transmittance caused by the metal and liner materials of stent. PMID:18951422

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

Science.gov (United States)

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

2018-04-01

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

Effects of 32P radioactive stents on in-stent restenosis in a double stent injury model of the porcine coronary arteries

International Nuclear Information System (INIS)

Kim, Han-Soo; Chan, Rosanna C.; Kollum, Marc; Au, Arthur; Tio, Fermin O.; Yazdi, Hamid A.; Ajani, Andrew E.; Waksman, Ron

2001-01-01

Background: The major limitation of coronary stenting remains in-stent restenosis, due to the development of neointimal proliferation. Radioactive stents have demonstrated the ability to reduce this proliferation in the healthy nonatherosclerotic porcine animal model. However, inhibition of tissue proliferation in the in-stent restenotic lesion in a porcine model is not well characterized. The objective of this study was to examine the efficacy and safety of the 32 P radioactive stent for the treatment of in-stent restenosis in a double stent injury model of the porcine coronaries. Methods and Materials: Eighteen coronary arteries in 9 pigs underwent nonradioactive stent (8 mm in length) implantation. Thirty days after the initial stent implantation, a 32 P radioactive stent (18 mm in length) with an activity of 0 and 18 μCi was implanted to cover the initial stent. The swine were killed 30 days after the second stent implantation. Histomorphometric analysis was performed for vessel area (VA), stent strut area (SSA), intimal area (IA), and lumen area (LA). Results: Injury scores, VA, SSA, and LA were similar among the control and radiated groups. Neointimal formation was significantly reduced after placement of radioactive stents as compared to control in both the overlapped (0.93±0.12 vs. 1.31±0.51 mm 2 , p 2 , p 32 P radioactive stents may be safe and effective in reducing neointimal formation leading to in-stent restenosis. Longer follow-up will be required to examine whether these positive findings can be maintained

Coronary artery bypass surgery or coronary stenting in diabetic patients: too soon to make a statement?

Energy Technology Data Exchange (ETDEWEB)

Rodriguez, Alfredo E., E-mail: arodriguez@centroceci.com.ar

2014-11-15

Diabetic patients have been associated with poor procedural and long term outcome if they were treated either with percutaneous coronary interventions or coronary artery bypass surgery. Recently several randomized clinical trials (RCT) in this subset of patients have been published showing a greater incidence of major adverse cardiovascular events, death/myocardial infarction/stroke, if they were treated with first generation drug eluting stents (DES) which was not observed previously in the bare metal stent era. However, almost simultaneously with this data, several RCT demonstrated better safety profile with new generation DES including biocompatible polymers, biodegradable polymers and lately complete absorbable DES, all of them showed reduction in adverse cardiac events compared to 1st generation DES in patients with diabetes. In this editorial we review the old and new randomized data in diabetic patients and conclude that there are many unresolved issues to make a definitive statement regarding which is the best revascularization preference in diabetic patients and the measured final efficacy of PCI and CABG will not be reached until the arrival of RCT using next generation DES, including complete absorbable scaffolds. - Highlights: • Diabetic patients have been associated with poor procedural and long term outcome if they were treated either with percutaneous coronary interventions or coronary artery bypass surgery. Recently several randomized clinical trials (RCT) in this subset of patients have been published showing a greater incidence of major adverse cardiovascular events, death/myocardial infarction/stroke, if they were treated with first generation drug eluting stents (DES) which was not observed previously in the bare metal stent era. • In recent years, several RCT demonstrated better safety profile with new generation DES including biocompatible polymers, biodegradable polymers and lately complete absorbable DES, all of them showed reduction in

Coronary artery bypass surgery or coronary stenting in diabetic patients: too soon to make a statement?

International Nuclear Information System (INIS)

Rodriguez, Alfredo E.

2014-01-01

Diabetic patients have been associated with poor procedural and long term outcome if they were treated either with percutaneous coronary interventions or coronary artery bypass surgery. Recently several randomized clinical trials (RCT) in this subset of patients have been published showing a greater incidence of major adverse cardiovascular events, death/myocardial infarction/stroke, if they were treated with first generation drug eluting stents (DES) which was not observed previously in the bare metal stent era. However, almost simultaneously with this data, several RCT demonstrated better safety profile with new generation DES including biocompatible polymers, biodegradable polymers and lately complete absorbable DES, all of them showed reduction in adverse cardiac events compared to 1st generation DES in patients with diabetes. In this editorial we review the old and new randomized data in diabetic patients and conclude that there are many unresolved issues to make a definitive statement regarding which is the best revascularization preference in diabetic patients and the measured final efficacy of PCI and CABG will not be reached until the arrival of RCT using next generation DES, including complete absorbable scaffolds. - Highlights: • Diabetic patients have been associated with poor procedural and long term outcome if they were treated either with percutaneous coronary interventions or coronary artery bypass surgery. Recently several randomized clinical trials (RCT) in this subset of patients have been published showing a greater incidence of major adverse cardiovascular events, death/myocardial infarction/stroke, if they were treated with first generation drug eluting stents (DES) which was not observed previously in the bare metal stent era. • In recent years, several RCT demonstrated better safety profile with new generation DES including biocompatible polymers, biodegradable polymers and lately complete absorbable DES, all of them showed reduction in

Angulated Stents-A Novel Stent Improvisation to Manage Difficult Post-tuberculosis Bronchial Stenosis.

Science.gov (United States)

Tay, Chee Kiang; Jeong, Byeong-Ho; Kim, Hojoong

2017-10-18

Post-tuberculosis bronchostenosis (PTBS), a complication of endobronchial tuberculosis is currently treated by bronchial stenting. However, in cases of angulated bronchial stenoses, difficulty is often encountered in stent insertion and maintenance, resulting in stent migration, granulation tissue overgrowth, and restenosis. To accommodate the angulated alignment of the stenosis, we devised an "angulated stent"-a novel improvisation of the conventional stent via splicing and suturing to achieve a resultant angulated shape. A retrospective review was undertaken to evaluate the performance of this stent. Among 283 PTBS patients who underwent interventional bronchoscopy at our center from 2004 to 2014, 21 were treated with at least one angulated stent. Clinical outcomes, including the stenting duration were investigated. After a median follow-up of 26 months, stent removal was successful in 7 (33.3%) out of 21 patients. In patients managed with angulated stents, the median duration to stent change or eventual removal was longer than those treated with straight tube stents (392 days vs. 86 days; p < 0.05). Angulated stents are a feasible treatment option in patients with angulated PTBS by reducing complications and prolonging the stent-changing interval.

A comparative evaluation of early stent occlusion among biliary conventional versus wing stents.

Science.gov (United States)

Khashab, Mouen A; Hutfless, Susan; Kim, Katherine; Lennon, Anne Marie; Canto, Marcia I; Jagannath, Sanjay B; Okolo, Patrick I; Shin, Eun Ji; Singh, Vikesh K

2012-06-01

Conventional plastic stents with a lumen typically have limited patency. The lumenless wing stent was engineered to overcome this problem. The objective of this study was to compare the incidence of early stent occlusion (symptomatic occlusion/cholangitis necessitating re-insertion within 90 days) for wing stents and conventional plastic stents. Patients with biliary pathology treated with plastic biliary stenting during the period 2003-2009 comprised the study cohort. Patients who had at least one biliary wing stent placed comprised the wing stent group, whereas patients who underwent only conventional stent plastic placement comprised the conventional stent group. Patients were stratified by indication: benign biliary strictures (group 1), malignant biliary strictures (group 2), or benign biliary non-stricture pathology (group 3). The association of stent type with the occurrence of primary outcome by indication was analyzed by use of multivariable logistic regression. Three-hundred and forty-six patients underwent 612 ERCP procedures with placement of plastic biliary stent(s). On multivariate analysis, early stent occlusion did not differ between the wing and conventional groups in groups 1, 2, and 3. Among patients who achieved primary outcome in group 2, significantly fewer patients in the wing group had cholangitis (6.7% vs. 39.1%, P = 0.03). Among patients who achieved primary outcome in group 3, significantly fewer patients in the wing group had cholangitis (10% vs. 50%, P = 0.03). Early stent occlusion was similar for wing stents and conventional plastic stents. Wing stents, however, were associated with a lower incidence of cholangitis in patients with malignant biliary obstruction and benign non-stricturing biliary pathology.

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

Science.gov (United States)

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

2017-04-01

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

Coronary and peripheral stenting in aorto-ostial protruding stents: The balloon assisted access to protruding stent technique.

Science.gov (United States)

Helmy, Tarek A; Sanchez, Carlos E; Bailey, Steven R

2016-03-01

Treatment of aorto-ostial in-stent restenosis lesions represents a challenge for interventional cardiologists. Excessive protrusion of the stent into the aorta may lead to multiple technical problems, such as difficult catheter reengagement of the vessel ostium or inability to re-wire through the stent lumen in repeat interventions. We describe a balloon assisted access to protruding stent technique in cases where conventional coaxial engagement of an aorto-ostial protruding stent with the guide catheter or passage of the guide wire through the true lumen is not feasible. This technique is applicable both in coronary and peripheral arteries. © 2015 Wiley Periodicals, Inc.

Interdisciplinary interventional therapy for tracheobronchial stenosis with modern metal net stents

International Nuclear Information System (INIS)

Rieger, J.; Linsenmaier, U.; Fedorowski, A.; Pfeifer, K.J.; Hautmann, H.; Huber, R.M.

2002-01-01

Study objectives: Assessment of the therapeutic potential of tracheobronchial stenting for obstructive tracheobronchial disease, in-vivo comparison of different stent types and development of helpful criteria for choosing the suitable stent type. Material and Methods: Prospective case analysis. Between 1993 and 1999 53 stents were implanted into the tracheobronchial system of 39 consecutive patients with benign or malignant airway obstruction. Every single stent (26 Strecker Stents, 18 Wallstents, 6 Accuflex Nitinolstents, 1 Dumon-, 1 Ruesch- and 1 Palmazstent) was recorded in an unified database. Analysis comprised clinical effectiveness, lung function if possible, relevant complications and radiologic follow-up parameters. The probability of their remaining within the tracheobronchial system, of their remaining undislocated and uncompressed was calculated using Kaplan-Meier analysis for three stent types. Results: Stent placement proved itself to be an effective treatment in 86% of the patients. Resistance could be normalized in 9/9 patients. Kaplan-Meier analysis clearly revealed a higher probability for the Wall- and Nitinolstent to remain within the tracheobronchial system and to remain uncompressed. Dislocation also occurred more rarely. Explanation of the Wallstent, however, if desired, was much more difficult compared to the Strecker stent. The Wallstent also occasionally led to the formation of granulation tissue especially at the proximal stent end and, as such, required reintervention. (orig.) [de

Short-term safety and efficacy of the biodegradable iron stent in mini-swine coronary arteries

Institute of Scientific and Technical Information of China (English)

WU Chao; QIU Hong; HU Xiao-ying; RUAN Ying-mao; TIAN Yi; CHU Yan; XU Xin-lin

2013-01-01

Background To overcome the drawbacks of permanent stents,biodegradable stents have been studied in recent years.The bioabsorbable polymer vascular scaffold (BVS) was the first bioabsorbable stent to undergo clinical trials,demonstrating safety and feasibility in the ABSORB studies.Iron can potentially serve as the biomaterial for biodegradable stents.This study aimed to assess the short-term safety and efficacy of a biodegradable iron stent in mini-swine coronary arteries.Methods Eight iron stents and eight cobalt chromium alloy (VISION) control stents were randomly implanted into the LAD and RCA of eight healthy mini-swine,respectively.Two stents of the same metal base were implanted into one animal.At 28 days the animals were sacrificed after coronary angiography,and histopathological examinations were performed.Results Histomorphometric measurements showed that mean neointimal thickness ((0.46±0.17) mm vs.(0.45±0.18)mm,P=0.878),neointimal area ((2.55±0.91) mm2 vs.(3.04±1.15) mm2,P=0.360) and percentage of area stenosis ((44.50±11.40)％ vs.(46.00±17.95)％,P=0.845) were not significantly different between the iron stents and VISION stents.There was no inflammation,thrombosis or necrosis in either group.The scanning electron microscopy (SEM) intimal injury scores (0.75±1.04 vs.0.88±0.99,P=0.809) and number of proliferating cell nuclear antigen (PCNA) positive staining cells were not significantly different between the two groups.The percentage of neointimal coverage by SEM examination was numerically higher in iron stents than in VISION stents ((84.38±14.50)％ vs.(65.00±22.04)％,P=0.057),but the difference was not statistically significant.Iron staining in the tissue surrounding the iron stents at 28 days was positive and the vascular wall adjacent to the iron stent had a brownish tinge,consistent with iron degradation.No abnormal histopathological changes were detected in coronary arteries or major organs.Conclusions The biodegradable iron stent has

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

Science.gov (United States)

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

2016-05-01

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

New treatment of iliac artery disease: focus on the Absolute Pro® Vascular Self-Expanding Stent System

Directory of Open Access Journals (Sweden)

Gates L

2013-09-01

Full Text Available Lindsay Gates, Jeffrey Indes Vascular and Endovascular Surgery, Yale University School of Medicine, New Haven, CT, USA Abstract: Management of iliac artery disease has evolved over the years, from a surgical-only approach to a primarily endovascular-only approach as the first line treatment option. This has been continuously improved upon with the advent of new devices and applied technologies. Most recently in particular, the literature has shown good, reliable outcomes with the use of self-expandable stents in iliac artery atherosclerotic lesions. Nevertheless, no device is without its limitations, and the Absolute Pro® Vascular Self-Expanding Stent System was designed with the intent of overcoming some of the shortcomings of other available stents while maintaining acceptable postprocedural outcomes. Based on preliminary industry-acquired data, it has achieved these goals and appears to be an emergent competitor for the treatment of both focal and complex iliac artery lesions. Keywords: Absolute-Pro®, iliac stent, self-expanding stents, atherosclerotic disease

The stenting strategy of drug-eluting stents for coronary artery disease in patients on dialysis

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Hiroshi Fujita

2014-12-01

Full Text Available Background: Reports regarding the relationship between the length and diameter of implanted drug-eluting stents and clinical and angiographic outcomes in dialysis patients are limited. Aim: We investigated the efficiency of drug-eluting stents for coronary artery disease in patients on dialysis from the viewpoint of stent sizing. Methods: Sirolimus-eluting stents were implanted in 88 lesions and bare metal stents were implanted in 43 lesions. We compared stenting strategy, major adverse cardiac events, and angiographic results between sirolimus-eluting stent and bare metal stent groups. Results: Stent diameter was smaller and stent length was longer in the sirolimus-eluting stent group than in the bare metal stent group in our routine practices. There was no significant between-group difference in late diameter loss. Rates of angiographic restenosis and target lesion revascularization were significantly higher in the sirolimus-eluting stent group than in the bare metal stent group. Although stent length was significantly longer and stent diameter was smaller in the sirolimus-eluting stent group, sirolimus-eluting stents did not improve the subsequent clinical and angiographic results compared with bare metal stents in dialysis patients. Conclusion: In dialysis patients, a longer length and/or smaller diameter sirolimus-eluting stent implantation was associated with high rates of restenosis and target lesion revascularization compared with bare metal stents.

Application of a novel retrievable self-expanding stent in intracranial aneurysm treatment

International Nuclear Information System (INIS)

Yang Zhigang; Liu Jianmin; Xu Yi; Huang Qinghai; Hong Bo; Zhao Wenyuan; Zhao Rui

2008-01-01

Objective: To assess the value of a novel retrievable self-expanding stent system (LEO) in intracranial aneurysm treatment. Methods: 43 patients with 44 intracranial aneurysms treated with LEO stent were retrospectively analized, including 16 aneurysms with single-stent deployment, 25 with stent-assisted technique, 2 with double-stent deployment and one with double-stent assisted coils. Follow up was carried out through imaging and clinical course. Results: The stent was easy for repositioning and all the stents were delivered successfully, except 1 stent with unsatisfactory position, 1 with acute in-stent thrombosis. During follow up, 1 case showed chronic in-stent thrombus and one with intimal hyperplasia. 22 aneurysms got compact coiled during procedure. Among 29 follow up cases, 72.4% aneurysms were cured or improved, 13.8% were stable and three dissection aneurysms enlarged within short period and two patients died. Conclusion: The new retrievable self-expanding stent (LEO), with the advantages of controlled delivery, easy deployment and choice for various types is a valuable system for vascular reconstruction of intracranial aneurysm with thrombosis. (authors)

Stent-in-Stent Technique for the Treatment of Proximal Bronchial Restenosis after Insertion of Metallic Stents: A Report of Two Cases

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Benjamin Bondue

2016-01-01

Full Text Available Endoscopic treatment of a bronchial restenosis previously treated by insertion of a partially covered self-expandable metallic stent (SEMS can be difficult. Classically, after recanalization of the bronchus, the stent is removed and replaced by a more adapted one. We report on two cases of proximal bronchial restenosis treated by insertion of an additional stent inside the lumen of the previously inserted stent using the stent-in-stent (SIS technique. The indications for the initial stent were malignancy in Patient 1 and posttransplant bronchial stenosis in Patient 2. Restenosis occurred at the proximal end of the stent within months in both cases. Stent removal and insertion of a new stent were considered, but this option was discarded because of an excessive risk of bronchial perforation and preference towards an alternative approach. In both cases, a second customized SEMS was placed using the SIS technique after ablation of the proximal end stenosis of the stent by argon plasma coagulation and/or dilation with a balloon. Recanalization of the bronchus was achieved in both cases without complications. The SIS technique is a valuable alternative to removal of SEMS in case of proximal bronchial restenosis.

Endovascular AAA exclusion: will stents with hooks and barbs prevent stent-graft migration?

Science.gov (United States)

Malina, M; Lindblad, B; Ivancev, K; Lindh, M; Malina, J; Brunkwall, J

1998-11-01

To investigate if stents with hooks and barbs will improve stent-graft fixation in the abdominal aorta. Sixteen- to 24-mm-diameter Dacron grafts were deployed inside cadaveric aortas. The grafts were anchored by stents as in endovascular abdominal aortic aneurysm repair. One hundred thirty-seven stent-graft deployments were carried out with modified self-expanding Z-stents with (A) no hooks and barbs (n = 75), (B) 4 5-mm-long hooks and barbs (n = 39), (C) 8 10-mm-long, strengthened hooks and barbs (n = 19), or (D) hooks only (n = 4). Increasing longitudinal traction was applied to determine the displacement force needed to extract the stent-grafts. The radial force of the stents was measured and correlated to the displacement force. The median (interquartile range) displacement force needed to extract grafts anchored by stent A was 2.5 N (2.0 to 3.4), stent B 7.8 N (7.4 to 10.8), and stent C 22.5 N (17.1 to 27.9), p barbs added anchoring strength. During traction, the weaker barbs were distorted or caused intimal tears. The stronger barbs engaged the entire aortic wall. The radial force of the stents had no impact on fixation, while aortic calcification and graft oversizing had marginal effects. Stent barbs and hooks increased the fixation of stent-grafts tenfold, while the radial force of stents had no impact. These data may prove important in future endograft development to prevent stent-graft migration after aneurysm exclusion.

Preliminary Report of Carotid Artery Stenting Using a Tapered Stent

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Jeong, Chang Woo; Kim, Dong Hyun; Hong, Seung; Jeong; Kim, Young Suk; Byun, Joo Nam; Oh, Jae Hee [Dept. of Radiology, Chosun University College of Medicine, Gwangju (Korea, Republic of); Ahn, Seong Hwan [Dept. of Neurology, Chosun University College of Medicine, Gwangju (Korea, Republic of)

2011-10-15

To analyze the results of carotid artery stenting using a tapered stent and to evaluate the effectiveness of the tapered stent compared to previously reported studies using non-tapered stents. From October 2008 to August 2010, elective carotid artery stenting using a tapered stent was attempted in 39 lesions from 36 consecutive patients. Post-procedural complications were evaluated by neurologic symptoms and magnetic resonance imaging. Restenosis or occlusion was evaluated by carotid Doppler ultrasound and computerized tomography with angiography. Newly developed neurologic symptoms were evaluated clinically. The self-expandable tapered stent was placed across the carotid artery stenosis. A total stroke was noted in 3 patients, while a major stroke was noted in 1 patient. On diffusion weighted imaging, new lesions were observed in 15 patients, but 13 patients were clinically silent. Follow-up imaging studies were performed in the 13 clinically silent lesions, and no evidence of restenosis or occlusion was found any of the 13 lesions. During clinical follow-up in 34 lesions from 31 patients, there were newly developed neurological symptoms in only 1 patient.

Expansion characteristics of coronary stents in focal stenoses

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Schmidt Wolfram

2017-09-01

Full Text Available The presented experimental in vitro approach was designed to assess the expansion behavior of stent systems in a resistant focal stenosis model with respect to a potential dog-boning effect. Five different stent systems (nominal diameter 3.0 mm were investigated. The focal stenosis was simulated by a stainless steel tube (ID ≤ 1.20 mm. Stent expansion was performed using a proprietary test device consisting of a test chamber with 37 °C water, 2-axis laser scanner and a pressure controller.

Predictive Factors of In-Stent Restenosis in Renal Artery Stenting: A Retrospective Analysis

International Nuclear Information System (INIS)

Vignali, Claudio; Bargellini, Irene; Lazzereschi, Michele; Cioni, Roberto; Petruzzi, Pasquale; Caramella, Davide; Pinto, Stefania; Napoli, Vinicio; Zampa, Virna; Bartolozzi, Carlo

2005-01-01

Purpose. To retrospectively evaluate the role of clinical and procedural factors in predicting in-stent restenosis in patients with renovascular disease treated by renal artery stenting. Methods. From 1995 to 2002, 147 patients underwent renal artery stenting for the treatment of significant ostial atherosclerotic stenosis. Patients underwent strict clinical and color-coded duplex ultrasound follow-up. Ninety-nine patients (111 stents), with over 6 months of continuous follow-up (mean 22±12 months, range 6-60 months), were selected and classified according to the presence (group A, 30 patients, 32 lesions) or absence (group B, 69 patients, 79 lesions) of significant in-stent restenosis. A statistical analysis was performed to identify possible preprocedural and procedural predictors of restenosis considering the following data: sex, age, smoking habit, diabetes mellitus, hypertension, serum creatinine, cholesterol and triglyceride levels, renal artery stenosis grade, and stent type, length and diameter. Results. Comparing group A and B patients (χ 2 test), a statistically significant relation was demonstrated between stent diameter and length and restenosis: the risk of in-stent restenosis decreased when the stent was ≥6 mm in diameter and between 15 and 20 mm in length. This finding was confirmed by multiple logistic regression analysis. Stent diameter and length were proved to be significantly related to in-stent restenosis also when evaluating only patients treated by Palmaz stent (71 stents). Conclusion. Although it is based on a retrospective analysis, the present study confirms the importance of correct stent selection in increasing long-term patency, using stents of at least 6 mm in diameter and with a length of approximately 15-20 mm

Modelling and simulating in-stent restenosis with complex automata

NARCIS (Netherlands)

Hoekstra, A.G.; Lawford, P.; Hose, R.

2010-01-01

In-stent restenosis, the maladaptive response of a blood vessel to injury caused by the deployment of a stent, is a multiscale system involving a large number of biological and physical processes. We describe a Complex Automata Model for in-stent restenosis, coupling bulk flow, drug diffusion, and

Semi-Automatic Electronic Stent Register: a novel approach to preventing ureteric stents lost to follow up.

Science.gov (United States)

Macneil, James W H; Michail, Peter; Patel, Manish I; Ashbourne, Julie; Bariol, Simon V; Ende, David A; Hossack, Tania A; Lau, Howard; Wang, Audrey C; Brooks, Andrew J

2017-10-01

Ureteric stents are indispensable tools in modern urology; however, the risk of them not being followed-up once inserted poses medical and medico-legal risks. Stent registers are a common solution to mitigate this risk; however, manual registers are logistically challenging, especially for busy units. Western Sydney Local Health District developed a novel Semi-Automatic Electronic Stent Register (SAESR) utilizing billing information to track stent insertions. To determine the utility of this system, an audit was conducted comparing the 6 months before the introduction of the register to the first 6 months of the register. In the first 6 months of the register, 457 stents were inserted. At the time of writing, two of these are severely delayed for removal, representing a rate of 0.4%. In the 6 months immediately preceding the introduction of the register, 497 stents were inserted, and six were either missed completely or severely delayed in their removal, representing a rate of 1.2%. A non-inferiority analysis found this to be no worse than the results achieved before the introduction of the register. The SAESR allowed us to improve upon our better than expected rate of stents lost to follow up or severely delayed. We demonstrated non-inferiority in the rate of lost or severely delayed stents, and a number of other advantages including savings in personnel costs. The semi-automatic register represents an effective way of reducing the risk associated with a common urological procedure. We believe that this methodology could be implemented elsewhere. © 2017 Royal Australasian College of Surgeons.

Intravascular stent graft with polyurethane and metallic stent: experimental study

International Nuclear Information System (INIS)

Do, Young Soo; Lee, Won Jae; Kim, Boo Kyung Han; Park, Jae Hyung; Lee, Hak Jong; Lee, Sang Hyun; Kim, Sung Hyun; Kim, Jong Won; Ha, Jongwon

1997-01-01

To evaluate the usefulness of a new model of the stent graft, and of tissue response related to placement of the stent graft. The stent graft was constructed from polyurethane (Pellethane) graft and Hanaro stent(12mm in diameter, 45mm in length, 10 bends). A stent grafts was inserted into the lower thoracic aorta in each of six adult mongrel dogs(body weight, 12-16kg). At one, two, four, and six months, follow-up studies of angiography and spiral CT angiography were preformed to evaluate wascular patency, vascular stenosis, and thrombus formation. Two dogs were sacrificed at 1month, 2months, and 6months after insertion of the stent graft and macroscopic, light microscopic, and scanning electron microscopic examinations of the aortic segment including the stent graft were performed to evaluate intimal hyperplasia, endothelial growth to the graft, and thrombus formation. During follow-up at one, two, four, and six months, angiography or spiral CT angiography showed 20-100% luminal stenosis or occlusion of the lower thoracic aorta by the thrombus and perigraft leaks in three dogs(50%), and collateral vessels caused by occlusion of the aorta in two (33.3%). On gross examination, there were thrombi of 1-5mm thickness at the graft portions in all dogs, and this thickness gradually increased. The mean thickness of intimal hyperplasia at the stent portion gradually increased from 120μm to 227μm and the mean thickness of intimal hyperplasia at the graft portion from 93μm to 914μm. This thickness was greater at the graft portion than at the stent portion. Scanning electron microscopy showed elliptical endothelial lining on the neointimal surfaces at each end of the graft. Thrombi caused stenosis or occlusion of the stent graft. In order for such a graft to be ideal, further study is needed

Robot-Assisted Antegrade In-Situ Fenestrated Stent Grafting

International Nuclear Information System (INIS)

Riga, Celia V.; Bicknell, Colin D.; Wallace, Daniel; Hamady, Mohamad; Cheshire, Nicholas

2009-01-01

To determine the technical feasibility of a novel approach of in-situ fenestration of aortic stent grafts by using a remotely controlled robotic steerable catheter system in the porcine model. A 65-kg pig underwent robot-assisted bilateral antegrade in-situ renal fenestration of an abdominal aortic stent graft with subsequent successful deployment of a bare metal stent into the right renal artery. A 16-mm iliac extension covered stent served as the porcine aortic endograft. Under fluoroscopic guidance, the graft was punctured with a 20-G customized diathermy needle that was introduced and kept in place by the robotic arm. The needle was exchanged for a 4 x 20 mm cutting balloon before successful deployment of the renal stent. Robot-assisted antegrade in-situ fenestration is technically feasible in a large mammalian model. The robotic system enables precise manipulation, stable positioning, and minimum instrumentation of the aorta and its branches while minimizing radiation exposure.

A comparison of outcomes between a lumen-apposing metal stent with electrocautery-enhanced delivery system and a bi-flanged metal stent for drainage of walled-off pancreatic necrosis.

Science.gov (United States)

Bekkali, Noor L H; Nayar, Manu K; Leeds, John S; Charnley, Richard M; Huggett, Matthew T; Oppong, Kofi W

2017-12-01

 Bi-flanged metal stents (BFMS) have shown promise in the drainage of walled-off pancreatic necrosis (WON), but their placement requires multiple steps and the use of other devices. More recently, a novel device consisting of a combined lumen-apposing metal stent (LAMS) and electrocautery-enhanced delivery system has been introduced. The aim of this study was to compare the placement and outcomes of the two devices.  This was a retrospective review of consecutive patients undergoing endoscopic ultrasound-guided placement of BFMS or LAMS for drainage of symptomatic WON. Data from procedures between October 2012 and December 2016 were taken from a prospectively maintained database. We compared technical and clinical success, procedure time, costs, and composite end point of significant events (adverse events, stent migration, additional percutaneous drainage) between BFMS and LAMS.  72 consecutive patients underwent placement of BFMS (40 patients, 44 stents) or LAMS (32 patients, 33 stents). Technical success was 91 % for BFMS and 97 % for LAMS. Clinical success was 65 % vs. 78 %, respectively. Median in-room procedure time was significantly shorter in the LAMS group (45 minutes [range 30 - 80]) than in the BFMS group (62.5 minutes [range 35 - 135]; P  comparable adverse events, success, and costs.

Temporary urethral covered stent - third year of experience

International Nuclear Information System (INIS)

Stojanovis, V.; Maksimovis, H.; Markovis, B.; Markovis, Z.

2006-01-01

Full text: In October 2003, a new generation of urethral stents ALLIUM, produced in Israel, were used at the Department of Interventional Radiology, CCS, in 18 patients with chronic stricture of bulbar urethra. The indications for insertion were determined according to well-known and recognized therapeutical protocols. The stent is made of nitinol wire with polyurethane cover. It is inserted under local anesthesia by a special self-expandable system that may be fixed or flexible. The stents we used were 3-6 cm long and 28 Fr wide. Radioscopic-assisted insertion was performed over formerly placed metal guide. Prior to insertion, balloon-catheter dilatation of stricture matching the stent width was carried out. Pre-insertion urethrotomy was performed in one case. The insertion technique is simple, presupposing the knowledge of older generations of techniques of urethral dilatation and insertion of self-expandable stents. The follow-up of results was done according to a priori established protocol including the following: UCG, uroflowmetry and interview with patients. Due to stent migration, the 'stent over stent' technique was applied in one case, while reposition by balloon-catheter outward traction was performed in two cases of caudal migration. No irritative discomforts were reported in the first 4 months after stent dwelling. Uroflowmetric controls verified at least four times better results than before the insertion. Given it is the question of covered stent, there is no possibility of proliferative secondary lumen obstruction. On account of soft structure and conic shape of posterior part of stent, no lesions of the external urethral sphincter were manifested. The stent is simply withdrawn after 6 months by outward traction using the forceps at the time when the stent construction turns into soft and straight wire. The first clinical experiences are very favorable and ALLIUM stent may be expected to be the stent of choice for chronic bulbar strictures

Parameter optimization method for longitudinal vibration absorber of ship shaft system

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LIU Jinlin

2017-05-01

Full Text Available The longitudinal vibration of the ship shaft system is the one of the most important factors of hull stern vibration, and it can be effectively minimized by installing a longitudinal vibration absorber. In this way, the vibration and noise of ships can be brought under control. However, the parameters of longitudinal vibration absorbers have a great influence on the vibration characteristics of the shaft system. As such, a certain shafting testing platform was studied as the object on which a finite model was built, and the relationship between longitudinal stiffness and longitudinal vibration in the shaft system was analyzed in a straight alignment state. Furthermore, a longitudinal damping model of the shaft system was built in which the parameters of the vibration absorber were non-dimensionalized, the weight of the vibration absorber was set as a constant, and an optimizing algorithm was used to calculate the optimized stiffness and damping coefficient of the vibration absorber. Finally, the longitudinal vibration frequency response of the shafting testing platform before and after optimizing the parameters of the longitudinal vibration absorber were compared, and the results indicated that the longitudinal vibration of the shafting testing platform was decreased effectively, which suggests that it could provide a theoretical foundation for the parameter optimization of longitudinal vibration absorbers.

Safety and efficacy of low-dose paclitaxel utilizing the cobra-P drug-eluting stent system with a novel biodegradable coating in de novo coronary lesions: The PLUS-ONE first-in-man study

International Nuclear Information System (INIS)

Calderas, Carlos; Condado, Jose Francisco; Condado, Jose Antonio; Flores, Alejandra; Mueller, Amy; Thomas, Jack; Nakatani, Daisaku; Honda, Yasuhiro; Waseda, Katsuhisa; Fitzgerald, Peter

2014-01-01

Background: The Cobra-P drug-eluting stent (DES) system consists of cobalt chromium alloy with bio-absorbable siloxane sol–gel matrix coating that elutes low dose paclitaxel within 6 months. The aim of this first-in-man trial was to evaluate the safety and performance of 2 doses of the Cobra-P DES. Methods: A total of 60 lesions (54 patients) were sequentially assigned to 2 different paclitaxel doses: group A (3.7 μg/18 mm, n = 30) or group B (8 μg/18 mm, n = 30). The primary endpoint was MACE at 4 months defined as cardiac death, myocardial infarction, and target lesion revascularization. Results: Patient and lesion characteristics were matched between the 2 groups except for male sex. MACE at 4 months was 3.3% and 0% respectively (P = 1.000) and at 1-year follow-up remained unchanged. In-stent late loss at 4 months was similar in both groups (0.36 ± 0.30 mm and 0.34 ± 0.20 mm P = .773). Conclusions: In this FIM study, implantation of the Cobra-P low dose paclitaxel-eluting stent with a bioabsorbable sol–gel coating was proven to be feasible and safe. Moderate neointimal proliferation was observed as well as an acceptable MACE rate up to 1 year

Safety and efficacy of low-dose paclitaxel utilizing the cobra-P drug-eluting stent system with a novel biodegradable coating in de novo coronary lesions: the PLUS-ONE first-in-man study.

Science.gov (United States)

Calderas, Carlos; Condado, Jose Francisco; Condado, Jose Antonio; Flores, Alejandra; Mueller, Amy; Thomas, Jack; Nakatani, Daisaku; Honda, Yasuhiro; Waseda, Katsuhisa; Fitzgerald, Peter

2014-01-01

The Cobra-P drug-eluting stent (DES) system consists of cobalt chromium alloy with bio-absorbable siloxane sol-gel matrix coating that elutes low dose paclitaxel within 6 months. The aim of this first-in-man trial was to evaluate the safety and performance of 2 doses of the Cobra-P DES. A total of 60 lesions (54 patients) were sequentially assigned to 2 different paclitaxel doses: group A (3.7 μg/18mm, n=30) or group B (8 μg/18mm, n=30). The primary endpoint was MACE at 4 months defined as cardiac death, myocardial infarction, and target lesion revascularization. Patient and lesion characteristics were matched between the 2 groups except for male sex. MACE at 4 months was 3.3% and 0% respectively (P=1.000) and at 1-year follow-up remained unchanged. In-stent late loss at 4 months was similar in both groups (0.36 ± 0.30mm and 0.34 ± 0.20mm P=.773). In this FIM study, implantation of the Cobra-P low dose paclitaxel-eluting stent with a bioabsorbable sol-gel coating was proven to be feasible and safe. Moderate neointimal proliferation was observed as well as an acceptable MACE rate up to 1 year. © 2014.

Safety and efficacy of low-dose paclitaxel utilizing the cobra-P drug-eluting stent system with a novel biodegradable coating in de novo coronary lesions: The PLUS-ONE first-in-man study

Energy Technology Data Exchange (ETDEWEB)

Calderas, Carlos [Instituto de Clinicas Urologia Tamanaco, Caracas (Venezuela, Bolivarian Republic of); Condado, Jose Francisco; Condado, Jose Antonio [Hospital Centro Medico de Caracas y Hospital Miguel Perez Carreno, Caracas (Venezuela, Bolivarian Republic of); Flores, Alejandra [Instituto de Clinicas Urologia Tamanaco, Caracas (Venezuela, Bolivarian Republic of); Mueller, Amy; Thomas, Jack [Medlogics Device Corporation, Santa Rosa, CA (United States); Nakatani, Daisaku; Honda, Yasuhiro; Waseda, Katsuhisa [Stanford University, Stanford, CA (United States); Fitzgerald, Peter, E-mail: crci-cvmed@stanford.edu [Stanford University, Stanford, CA (United States)

2014-01-15

Background: The Cobra-P drug-eluting stent (DES) system consists of cobalt chromium alloy with bio-absorbable siloxane sol–gel matrix coating that elutes low dose paclitaxel within 6 months. The aim of this first-in-man trial was to evaluate the safety and performance of 2 doses of the Cobra-P DES. Methods: A total of 60 lesions (54 patients) were sequentially assigned to 2 different paclitaxel doses: group A (3.7 μg/18 mm, n = 30) or group B (8 μg/18 mm, n = 30). The primary endpoint was MACE at 4 months defined as cardiac death, myocardial infarction, and target lesion revascularization. Results: Patient and lesion characteristics were matched between the 2 groups except for male sex. MACE at 4 months was 3.3% and 0% respectively (P = 1.000) and at 1-year follow-up remained unchanged. In-stent late loss at 4 months was similar in both groups (0.36 ± 0.30 mm and 0.34 ± 0.20 mm P = .773). Conclusions: In this FIM study, implantation of the Cobra-P low dose paclitaxel-eluting stent with a bioabsorbable sol–gel coating was proven to be feasible and safe. Moderate neointimal proliferation was observed as well as an acceptable MACE rate up to 1 year.

Differentiated analysis of an everolimus-eluting stent and a paclitaxel-eluting stent among higher risk subgroups for restenosis: results from the SPIRIT II trial.

Science.gov (United States)

Khattab, Ahmed A; Richardt, Gert; Verin, Vitali; Kelbaek, Henning; Macaya, Carlos; Berland, Jacques; Miquel-Hebert, Karine; Dorange, Cécile; Serruys, Patrick W

2008-03-01

Restenosis is higher among certain subpopulations when subjected to percutaneous coronary interventions even when using drug-eluting stents. The randomised SPIRIT II trial demonstrated the superiority of the XIENCE V Everolimus Eluting Coronary Stent System over the TAXUS Paclitaxel-Eluting Stent System in terms of in-stent late loss at six months among 300 patients treated for de novo native coronary artery lesions. In this post-hoc analysis of SPIRIT II we focused on six-month angiographic outcomes of diabetic patients (n=69), left anterior descending arteries (n=149), long lesions >20 mm (n=43), small vessels B2 and C lesions (n=233). In-stent late loss was consistently less among all subgroups when treated by everolimus-eluting stents compared to paclitaxel-eluting stents: diabetics 0.15+/-0.26 mm versus 0.39+/-0.34 mm, p=0.006; LAD 0.12+/-0.23 mm versus 0.44+/-0.37 mm, pB2/C lesions 0.12+/-0.31 mm versus 0.36+/-0.36 mm, pSPIRIT II trial population.

An easier method for performing a pancreaticojejunostomy for the soft pancreas using a fast-absorbable suture

Institute of Scientific and Technical Information of China (English)

Kenichi Hakamada; Shunji Narumi; Yoshikazu Toyoki; Masaki Nara; Kenosuke Ishido; Takuya Miura; Norihito; Mutsuo Sasaki

2008-01-01

AIM:To clarify the usefulness of a new method for performing a pancreaticojejunostomy by using a fastabsorbable suture material irradiated polyglactin 910,and a temporary stent tube for a narrow pancreatic duct with a soft pancreatic texture.METHODS:Among 63 consecutive patients with soft pancreas undergoing a pancreaticoduodenectomy from 2003 to 2006,35 patients were treated with a new reconstructive method.Briefly,after the pancreatic transaction,a stent tube was inserted into the lumen of the pancreatic duct and ligated with it by a fastabsorbable suture.Another tip of the stent tube was introduced into the intestinal lumen at the jejunal limb,where a purse-string suture was made by another fast-absorbable suture to roughly fix the tube.The pancreaticojejunostomy was completed by ligating two fast-absorbable sutures to approximate the ductal end and the jejunal mucosa,and by adding a rough anastomosis between the pancreatic parenchyma and the seromuscular layer of the jejunum.The initial surgical results with this method were retrospectively compared with those of the 28 patients treated with conventional duct-to-mucosa anastomosis.RESULTS:The incidences of postoperative morbidity including pancreatic fistula were comparable between the two groups (new;3%-17% vs conventional;7%-14% according to the definitions).There was no mortality and re-admission.Late complications were also rarely seen.CONCLUSION:A pancreaticojejunostomy using an irradiated polyglactin 910 suture material and a temporary stent is easy to perform and is feasible even in cases with a narrow pancreatic duct and a normal soft pancreas.

Stent Coating Integrity of Durable and Biodegradable Coated Drug Eluting Stents.

Science.gov (United States)

Yazdani, Saami K; Sheehy, Alexander; Pacetti, Stephen; Rittlemeyer, Brandon; Kolodgie, Frank D; Virmani, Renu

2016-10-01

Coatings consisting of a polymer and drug are widely used in drug-eluting stents (DES) and are essential in providing programmable drug release kinetics. Among other factors, stent coating technologies can influence blood compatibility, affect acute and sub-acute healing, and potentially trigger a chronic inflammatory response. The aim of this study was to investigate the short-term (7 and 28 days) and long-term (90 and 180 days) coating integrity of the Xience Prime Everolimus-Eluting Stent (EES), Resolute Zotarolimus-Eluting Stent (ZES), Taxus Paclitaxel-Eluting Stent (PES), and Nobori Biolimus A9-Eluting Stent (BES) in a rabbit ilio-femoral stent model. Stented arteries (n = 48) were harvested and the tissue surrounding the implanted stents digested away with an enzymatic solution. Results demonstrated that the majority of struts of EES were without any coating defects with a few struts showing minor defects. Similarly, for the ZES, most of the struts were without coating defects at all time points except at 180 days. The majority of PES demonstrated mostly webbing and uneven coating. In the BES group, the majority of strut coating showed polymer cracking. Overall, the EES and ZES had fewer coating defects than the PES and BES. Coating defects, however increase over time for the ZES, whereas the percent of coating irregularities remained constant for the EES. These results provide, for the first time, a comparison of the long-term durability of these drug-eluting stent coatings in vivo. © 2016, Wiley Periodicals, Inc.

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

Science.gov (United States)

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 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. Copyright © 2015 Elsevier Inc. All rights reserved.

4D phase contrast flow imaging for in-stent flow visualization and assessment of stent patency in peripheral vascular stents--a phantom study.

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Bunck, Alexander C; Jüttner, Alena; Kröger, Jan Robert; Burg, Matthias C; Kugel, Harald; Niederstadt, Thomas; Tiemann, Klaus; Schnackenburg, Bernhard; Crelier, Gerard R; Heindel, Walter; Maintz, David

2012-09-01

4D phase contrast flow imaging is increasingly used to study the hemodynamics in various vascular territories and pathologies. The aim of this study was to assess the feasibility and validity of MRI based 4D phase contrast flow imaging for the evaluation of in-stent blood flow in 17 commonly used peripheral stents. 17 different peripheral stents were implanted into a MR compatible flow phantom. In-stent visibility, maximal velocity and flow visualization were assessed and estimates of in-stent patency obtained from 4D phase contrast flow data sets were compared to a conventional 3D contrast-enhanced magnetic resonance angiography (CE-MRA) as well as 2D PC flow measurements. In all but 3 of the tested stents time-resolved 3D particle traces could be visualized inside the stent lumen. Quality of 4D flow visualization and CE-MRA images depended on stent type and stent orientation relative to the magnetic field. Compared to the visible lumen area determined by 3D CE-MRA, estimates of lumen patency derived from 4D flow measurements were significantly higher and less dependent on stent type. A higher number of stents could be assessed for in-stent patency by 4D phase contrast flow imaging (n=14) than by 2D phase contrast flow imaging (n=10). 4D phase contrast flow imaging in peripheral vascular stents is feasible and appears advantageous over conventional 3D contrast-enhanced MR angiography and 2D phase contrast flow imaging. It allows for in-stent flow visualization and flow quantification with varying quality depending on stent type. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

[Evaluation of Radiation Dose during Stent-graft Treatment Using a Hybrid Operating Room System].

Science.gov (United States)

Haga, Yoshihiro; Chida, Kouichi; Kaga, Yuji; Saitou, Kazuhisa; Arai, Takeshi; Suzuki, Shinichi; Iwaya, Yoshimi; Kumasaka, Eriko; Kataoka, Nozomi; Satou, Naoto; Abe, Mitsuya

2015-12-01

In recent years, aortic aneurysm treatment with stent graft grafting in the X-ray fluoroscopy is increasing. This is an endovascular therapy, because it is a treatment which includes the risk of radiation damage, having to deal with radiation damage, to know in advance is important. In this study, in order to grasp the trend of exposure stent graft implantation in a hybrid operating room (OR) system, focusing on clinical data (entrance skin dose and fluoroscopy time), was to count the total. In TEVAR and EVAR, fluoroscopy time became 13.40 ± 7.27 minutes, 23.67 ± 11.76 minutes, ESD became 0.87 ± 0.41 mGy, 1.11 ± 0.57 mGy. (fluoroscopy time of EVAR was 2.0 times than TEVAR. DAP of EVAR was 1.2 times than TEVAR.) When using the device, adapted lesions and usage are different. This means that care changes in exposure-related factors. In this study, exposure trends of the stent graft implantation was able to grasp. It can be a helpful way to reduce/optimize the radiation dose in a hybrid OR system.

Causes and prevention of in-stent restenosis of vertebral artery origin after stenting

International Nuclear Information System (INIS)

Zhao Huipin; Li Shenmao; Zhang Guangping

2010-01-01

Vertebral artery stenosis is an important cause of posterior circulation stroke. Vertebral artery stenosis most commonly occurs at its origin site. In recent years, balloon angioplasty and stent implantation have been widely employed in the treatment of vertebral artery origin stenosis. However, the long term outcome of stent implantation is affected by in-stent restenosis. Multiple contributory factors have been identified, but clear understanding of the overall underlying mechanism remains an enigma. With the development of pathophysiology, prevention and treatment methods of in-stent restenosis have been improved. In recent years, drug-eluting stents, radioactive stents and magnetic stents have been widely applied. To some extent, these stents and drug therapy can solve the problem of restenosis. This article aims to review the clinical application and the up-to-date research progresses in preventing and managing vertebral artery origin restenosis. (authors)

Esophageal Stent for Refractory Variceal Bleeding: A Systemic Review and Meta-Analysis

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Xiao-Dong Shao

2016-01-01

Full Text Available Background. Preliminary studies suggest that covered self-expandable metal stents may be helpful in controlling esophageal variceal bleeding. Aims. To evaluate the effectiveness and safety of esophageal stent in refractory variceal bleeding in a systematic review and meta-analysis. Methods. A comprehensive literature search was conducted on PubMed, EMBASE, and Cochrane Library covering the period from January 1970 to December 2015. Data were selected and abstracted from eligible studies and were pooled using a random-effects model. Heterogeneity was assessed using I2 test. Results. Five studies involving 80 patients were included in the analysis. The age of patients ranged from 18 to 91 years. The mean duration of follow-up was 46.8 d (range, 30–60 d. The success rate of stent deployment was 96.7% (95% CI: 91.6%–99.5% and complete response to esophageal stenting was in 93.9% (95% CI: 82.2%–99.6%. The incidence of rebleeding was 13.2% (95% CI: 1.8%–32.8% and the overall mortality was 34.5% (95% CI: 24.8%–44.8%. Most of patients (87.4% died from hepatic or multiple organ failure, and only 12.6% of patients died from uncontrolled bleeding. There was no stent-related complication reported and the incidence of stent migration was 21.6% (95% CI: 4.7%–46.1%. Conclusion. Esophageal stent may be considered in patients with variceal bleeding refractory to conventional therapy.

Outcomes of the single-stent versus kissing-stents technique in asymmetric complex aortoiliac bifurcation lesions.

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

2015-07-01

This study investigated the outcomes of single-stent vs kissing-stents techniques in asymmetric complex aortoiliac bifurcation (ACAB) lesions. We retrospectively investigated 80 consecutive patients (69 males, 66.6 ± 8.7 years) treated with a single stent and 30 patients (26 males, 67.1 ± 7.7 years) treated with kissing stents for ACAB between January 2005 and December 2012 from a single-center cohort. A ACAB lesion was defined as a symptomatic unilateral common iliac artery stenosis (>50%) combined with intermediate stenosis (30%-50%) in the contralateral common iliac artery ostium. The primary end point was the primary patency of the ACAB. The baseline clinical characteristics did not differ significantly between the single-stent and the kissing-stents group. Technical success was achieved in all patients. The single-stent group required fewer stents (1.3 ± 0.5 vs 2.3 ± 0.8; P stent group (3%) required bailout kissing stents because of plaque shift to the contralateral side. The major complication rates were 8% in single-stent vs 13% in the kissing-stent group, which was similar (P = .399). At 3 years, the single-stent and kissing-stents group had similar rates of primary patency (89% vs 87%; P = .916) and target lesion revascularization-free survival (93% vs 87%; P = .462). The single-stent technique in ACAB was safe and showed midterm outcomes comparable with those of kissing stents. Considering the benefits, such as fewer stents, less bilateral femoral access, and the availability of contralateral access for future intervention, the single-stent technique may be an advantageous treatment option in ACAB. Copyright © 2015 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

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

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

2016-02-05

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

Comparison of Acute Thrombogenicity for Metallic and Polymeric Bioabsorbable Scaffolds: Magmaris Versus Absorb in a Porcine Arteriovenous Shunt Model.

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Waksman, Ron; Lipinski, Michael J; Acampado, Eduardo; Cheng, Qi; Adams, Lila; Torii, Sho; Gai, Jiaxiang; Torguson, Rebecca; Hellinga, David M; Westman, Peter C; Joner, Michael; Zumstein, Philine; Kolodgie, Frank D; Virmani, Renu

2017-08-01

A comparison in acute thrombogenicity between the Magmaris sirolimus-eluting bioabsorbable magnesium scaffold and the Absorb bioresorbable vascular scaffold has not been performed. This study assessed acute thrombogenicity of Magmaris compared with Absorb and the Orsiro hybrid drug-eluting stent in a porcine arteriovenous shunt model. An ex vivo porcine carotid jugular arteriovenous shunt was established and connected to SYLGARD tubing containing the Magmaris, Absorb, and Orsiro scaffolds/stents and allowed to run in the shunt for a maximum of 1 hour. Twelve shunts (2 shunt runs per pig) were run comparing the 3 scaffolds in alternating order. Nested generalized linear mixed models were used to compare variables between scaffold groups while adjusting for variability between shunt runs. Confocal fluorescent microscopy costaining CD61/CD42b demonstrated that both Magmaris (3.0%) and Orsiro (4.6%) had less platelet coverage of the total scaffold compared with Absorb (21.8%). Scanning electron microscopy demonstrated significantly less thrombus deposition to Magmaris as a percentage of the total scaffold compared with Absorb (5.0% versus 16.1%, P =0.02). Magmaris had significantly less PM-1-positive neutrophil and CD14-positive monocyte adherence compared with both Orsiro and Absorb. Orsiro had significantly less monocyte deposition compared with Absorb. Despite a similar scaffold strut thickness, the Magmaris sirolimus-eluting bioabsorbable magnesium scaffold was significantly less thrombogenic compared with the Absorb bioresorbable vascular scaffold in an ex vivo porcine arteriovenous shunt model. Further studies are needed to determine whether the reduced thrombogenicity of Magmaris will result in reductions in major cardiovascular events. © 2017 American Heart Association, Inc.

Endovascular repair of arterial iliac vessel wall lesions with a self-expandable nitinol stent graft system.

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Birger Mensel

Full Text Available To assess the therapeutic outcome after endovascular repair of iliac arterial lesions (IALs using a self-expandable Nitinol stent graft system.Between July 2006 and March 2013, 16 patients (13 males, mean age: 68 years with a self-expandable Nitinol stent graft. A total of 19 lesions were treated: nine true aneurysms, two anastomotic aneurysms, two dissections, one arteriovenous fistula, two type 1B endoleaks after endovascular aneurysm repair, one pseudoaneurysm, and two perforations after angioplasty. Pre-, intra-, and postinterventional imaging studies and the medical records were analyzed for technical and clinical success and postinterventional complications.The primary technical and clinical success rate was 81.3% (13/16 patients and 75.0% (12/16, respectively. Two patients had technical failure due to persistent type 1A endoleak and another patient due to acute stent graft thrombosis. One patient showed severe stent graft kinking on the first postinterventional day. In two patients, a second intervention was performed. The secondary technical and clinical success rate was 87.5% (14/16 and 93.8% (15/16. The minor complication rate was 6.3% (patient with painful hematoma at the access site. The major complication rate was 6.3% (patient with ipsilateral deep vein thrombosis. During median follow-up of 22.4 months, an infection of the aneurysm sac in one patient and a stent graft thrombosis in another patient were observed.Endovascular repair of various IALs with a self-expandable Nitinol stent graft is safe and effective.

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

Science.gov (United States)

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

2018-06-22

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

Delayed cerebral infarction due to stent folding deformation following carotid artery stenting

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Seo, Kwon Duk; Lee, Kyung Yul; Suh, Sang Hyun [Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul (Korea, Republic of); Kim, Byung Moon [Dept. of Radiology, Severance Hospital, Yonsei University College of Medicine, Seoul (Korea, Republic of)

2014-12-15

We report a case of delayed cerebral infarction due to stent longitudinal folding deformation following carotid artery stenting using a self-expandable stent with an open-cell design. The stented segment of the left common carotid artery was divided into two different lumens by this folding deformation, and the separated lumens became restricted with in-stent thrombosis. Although no established method of managing this rare complication exists, a conservative approach was taken with administration of anticoagulant and dual antiplatelet therapy. No neurological symptoms were observed during several months of clinical follow-up after discharge.

Evaluation of the Autoparametric Pendulum Vibration Absorber for a Duffing System

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Benjamın Vazquez-Gonzalez

2008-01-01

Full Text Available In this work we study the frequency and dynamic response of a damped Duffing system attached to a parametrically excited pendulum vibration absorber. The multiple scales method is applied to get the autoparametric resonance conditions and the results are compared with a similar application of a pendulum absorber for a linear primary system. The approximate frequency analysis reveals that the nonlinear dynamics of the externally excited system are suppressed by the pendulum absorber and, under this condition, the primary Duffing system yields a time response almost equivalent to that obtained for a linear primary system, although the absorber frequency response is drastically modified and affected by the cubic stiffness, thus modifying the jumps defined by the fixed points. In the absorber frequency response can be appreciated a good absorption capability for certain ranges of nonlinear stiffness and the internal coupling is maintained by the existing damping between the pendulum and the primary system. Moreover, the stability of the coupled system is also affected by some extra fixed points introduced by the cubic stiffness, which is illustrated with several amplitude-force responses. Some numerical simulations of the approximate frequency responses and dynamic behavior are performed to show the steady-state and transient responses.

MR Angiography of Peripheral Arterial Stents: In Vitro Evaluation of 22 Different Stent Types

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Matthias C. Burg

2011-01-01

Full Text Available Purpose. To evaluate stent lumen visibility of a large sample of different peripheral arterial (iliac, renal, carotid stents using magnetic resonance angiography in vitro. Materials and Methods. 21 different stents and one stentgraft (10 nitinol, 7 316L, 2 tantalum, 1 cobalt superalloy, 1 PET + cobalt superalloy, and 1 platinum alloy were examined in a vessel phantom (vessel diameters ranging from 5 to 13 mm filled with a solution of Gd-DTPA. Stents were imaged at 1.5 Tesla using a T1-weighted 3D spoiled gradient-echo sequence. Image analysis was performed measuring three categories: Signal intensity in the stent lumen, lumen visibility of the stented lumen, and homogeneity of the stented lumen. The results were classified using a 3-point scale (good, intermediate, and poor results. Results. 7 stents showed good MR lumen visibility (4x nitinol, 2x tantalum, and 1x cobalt superalloy. 9 stents showed intermediate results (5x nitinol, 2x 316L, 1x PET + cobalt superalloy, and 1x platinum alloy and 6 stents showed poor results (1x nitinol, and 5x 316L. Conclusion. Stent lumen visibility varies depending on the stent material and type. Some products show good lumen visibility which may allow the detection of stenoses inside the lumen, while other products cause artifacts which prevent reliable evaluation of the stent lumen with this technique.

Research on ration selection of mixed absorbent solution for membrane air-conditioning system

International Nuclear Information System (INIS)

Li, Xiu-Wei; Zhang, Xiao-Song; Wang, Fang; Zhao, Xiao; Zhang, Zhuo

2015-01-01

Highlights: • We derive models of the membrane air-conditioning system with mixed absorbents. • We make analysis on system COP, cost-effectiveness and economy. • The paper provides a new method for ideal absorbent selection. • The solutes concentration of 50% achieves the best cost-effectiveness and the economy. - Abstract: Absorption air-conditioning system is a good alternative to vapor compression system for developing low carbon society. To improve the performance of the traditional absorption system, the membrane air-conditioning system is configured and its COP can reach as high as 6. Mixed absorbents are potential for cost reduction of the membrane system while maintaining a high COP. On the purpose of finding ideal mixed absorbent groups, this paper makes analysis on COP, cost-effectiveness and economy of the membrane system with mixed LiBr–CaCl 2 absorbent solution. The models of the system have been developed for the analysis. The results show the COP is higher for the absorbent groups with lower concentration of the total solute and higher concentration ratio of LiBr. It also reveals when the total solutes concentration is about 50%, it achieves the best cost-effectiveness and the economy. The process of the analysis provides a useful method for mixed absorbents selection

Risk Factors and Clinical Evaluation of Superficial Femoral Artery Stent Fracture: Prote'ge'GPS Stent

International Nuclear Information System (INIS)

Lee, Da Un; Kim, Jae Kyu; Jung, Hye Doo; Huh, Tae Wook; Yim, Nam Yeol; Oh, Hyun jun; Choi, Soo Jin Na; Chang, Nam Kyu

2010-01-01

To evaluate the occurrence of superficial femoral artery stent fractures, the risk factors of stent fracture, and the relationship between fractures and clinical findings. Of the 38 patients who underwent treatment with Prote'ge'GPS stenting due to arterial occlusions on the superficial femoral artery, 17 also underwent a clinical analysis. Forty-three stents were inserted in the 17 superficial femoral arteries, ranging between 15 and 50 cm in length, with a mean treated length of 26.4 cm (15-50 cm). A fracture was evaluated by taking a PA and lateral simple radiography, as well as a follow-up evaluation accompanied with a CT angiography, DSA, and a color Doppler sonography. The examination involved the assessment of the difference between bone fractures due to length, placement, and frequency. Fractures occurred in 13 of 43 stents (30.2%). A total of 10 (71.4%) occurred in the upper third, compared to 4 (28.6%) in the lower third of the superficial femoral artery. In addition, 10 stents (71.4%) had a single strut fracture, whereas 4 (28.6%) had multiple strut fractures. A stent fracture occurred more frequently when the stents and lesions were longer (p=0.021, 0.012) and the stents were inserted near the joint. However, there was no significant relationship between stent numbers and the fractures (p=0.126). When the stents were inserted along the popliteal artery, a stent fracture occurred more frequently in the lower third of the artery. The stent fractures did not significantly influence the patency rate of the stented artery (p=0.44) Prote'ge'GPS stents in the superficial femoral artery revealed a considerable number of fractures and the fracture frequency showed a significant relationship with the length of stents and lesions. The closer stent insertion was to the joints, the more frequently fractures occurred. There were no evident significant relationships between the presence of stent fractures and the patency of the stented arteries

4D phase contrast flow imaging for in-stent flow visualization and assessment of stent patency in peripheral vascular stents – A phantom study

International Nuclear Information System (INIS)

Bunck, Alexander C.; Jüttner, Alena; Kröger, Jan Robert; Burg, Matthias C.; Kugel, Harald; Niederstadt, Thomas; Tiemann, Klaus; Schnackenburg, Bernhard; Crelier, Gerard R.

2012-01-01

Purpose: 4D phase contrast flow imaging is increasingly used to study the hemodynamics in various vascular territories and pathologies. The aim of this study was to assess the feasibility and validity of MRI based 4D phase contrast flow imaging for the evaluation of in-stent blood flow in 17 commonly used peripheral stents. Materials and methods: 17 different peripheral stents were implanted into a MR compatible flow phantom. In-stent visibility, maximal velocity and flow visualization were assessed and estimates of in-stent patency obtained from 4D phase contrast flow data sets were compared to a conventional 3D contrast-enhanced magnetic resonance angiography (CE-MRA) as well as 2D PC flow measurements. Results: In all but 3 of the tested stents time-resolved 3D particle traces could be visualized inside the stent lumen. Quality of 4D flow visualization and CE-MRA images depended on stent type and stent orientation relative to the magnetic field. Compared to the visible lumen area determined by 3D CE-MRA, estimates of lumen patency derived from 4D flow measurements were significantly higher and less dependent on stent type. A higher number of stents could be assessed for in-stent patency by 4D phase contrast flow imaging (n = 14) than by 2D phase contrast flow imaging (n = 10). Conclusions: 4D phase contrast flow imaging in peripheral vascular stents is feasible and appears advantageous over conventional 3D contrast-enhanced MR angiography and 2D phase contrast flow imaging. It allows for in-stent flow visualization and flow quantification with varying quality depending on stent type

Partially Covered Metal Stents May Not Prolong Stent Patency Compared to Uncovered Stents in Unresectable Malignant Distal Biliary Obstruction

Science.gov (United States)

Kim, Jae Yun; Ko, Gyu Bong; Lee, Tae Hoon; Park, Sang-Heum; Lee, Yun Nah; Cho, Young Sin; Jung, Yunho; Chung, Il-Kwun; Choi, Hyun Jong; Cha, Sang-Woo; Moon, Jong Ho; Cho, Young Deok; Kim, Sun-Joo

2017-01-01

Background/Aims Controversy still exists regarding the benefits of covered self-expandable metal stents (SEMSs) compared to uncovered SEMSs. We aimed to compare the patency and stent-related adverse events of partially covered SEMSs (PC-SEMSs) and uncovered SEMSs in unresectable malignant distal biliary obstruction. Methods A total of 134 patients who received a PC-SEMS or uncovered SEMS for palliation of unresectable malignant distal biliary obstruction were reviewed retrospectively. The main outcome measures were stent patency, stent-related adverse events, and overall survival. Results The median stent patency was 118 days (range, 3 to 802 days) with PC-SEMSs and 105 days (range, 2 to 485 days) with uncovered SEMSs (p=0.718). The overall endoscopic revision rate due to stent dysfunction was 36.6% (26/71) with PC-SEMSs and 36.5% (23/63) with uncovered SEMSs (p=0.589). Tumor ingrowth was more frequent with uncovered SEMSs (4.2% vs 19.1%, p=0.013), but migration was more frequent with PC-SEMSs (11.2% vs 1.5%, p=0.04). The incidence of stent-related adverse events was 2.8% (2/71) with PC-SEMSs and 9.5% (6/63) with uncovered SEMSs (p=0.224). The median overall survival was 166 days with PC-SEMSs and 168 days with uncovered SEMSs (p=0.189). Conclusions Compared to uncovered SEMSs, PC-SEMSs did not prolong stent patency in unresectable malignant distal biliary obstruction. Stent migration was more frequent with PC-SEMSs. However, tumor ingrowth was less frequent with PC-SEMSs compared to uncovered SEMSs. PMID:28208003

Dose-volume histograms based on serial intravascular ultrasound: a calculation model for radioactive stents

International Nuclear Information System (INIS)

Kirisits, Christian; Wexberg, Paul; Gottsauner-Wolf, Michael; Pokrajac, Boris; Ortmann, Elisabeth; Aiginger, Hannes; Glogar, Dietmar; Poetter, Richard

2001-01-01

Background and purpose: Radioactive stents are under investigation for reduction of coronary restenosis. However, the actual dose delivered to specific parts of the coronary artery wall based on the individual vessel anatomy has not been determined so far. Dose-volume histograms (DVHs) permit an estimation of the actual dose absorbed by the target volume. We present a method to calculate DVHs based on intravascular ultrasound (IVUS) measurements to determine the dose distribution within the vessel wall. Materials and methods: Ten patients were studied by intravascular ultrasound after radioactive stenting (BX Stent, P-32, 15-mm length) to obtain tomographic cross-sections of the treated segments. We developed a computer algorithm using the actual dose distribution of the stent to calculate differential and cumulative DVHs. The minimal target dose, the mean target dose, the minimal doses delivered to 10 and 90% of the adventitia (DV10, DV90), and the percentage of volume receiving a reference dose at 0.5 mm from the stent surface cumulated over 28 days were derived from the DVH plots. Results were expressed as mean±SD. Results: The mean activity of the stents was 438±140 kBq at implantation. The mean reference dose was 111±35 Gy, whereas the calculated mean target dose within the adventitia along the stent was 68±20 Gy. On average, DV90 and DV10 were 33±9 Gy and 117±41 Gy, respectively. Expanding the target volume to include 2.5-mm-long segments at the proximal and distal ends of the stent, the calculated mean target dose decreased to 55±17 Gy, and DV 90 and DV 10 were 6.4±2.4 Gy and 107±36 Gy, respectively. Conclusions: The assessment of DVHs seems in principle to be a valuable tool for both prospective and retrospective analysis of dose-distribution of radioactive stents. It may provide the basis to adapt treatment planning in coronary brachytherapy to the common standards of radiotherapy

A Comprehensive Review of the Techniques on Regenerative Shock Absorber Systems

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Ran Zhang

2018-05-01

Full Text Available In this paper, the current technologies of the regenerative shock absorber systems have been categorized and evaluated. Three drive modes of the regenerative shock absorber systems, namely the direct drive mode, the indirect drive mode and hybrid drive mode are reviewed for their readiness to be implemented. The damping performances of the three different modes are listed and compared. Electrical circuit and control algorithms have also been evaluated to maximize the power output and to deliver the premium ride comfort and handling performance. Different types of parameterized road excitations have been applied to vehicle suspension systems to investigate the performance of the regenerative shock absorbers. The potential of incorporating nonlinearity into the regenerative shock absorber design analysis is discussed. The research gaps for the comparison of the different drive modes and the nonlinearity analysis of the regenerative shock absorbers are identified and, the corresponding research questions have been proposed for future work.

Self-expandable stent loaded with {sup 125}I seeds: Feasibility and safety in a rabbit model

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Guo Jinhe [Department of Radiology, Zhong-Da Hospital, Southeast University, 87 Dingjiaqiao Road, Nanjing 210009 (China); Teng Gaojun [Department of Radiology, Zhong-Da Hospital, Southeast University, 87 Dingjiaqiao Road, Nanjing 210009 (China)]. E-mail: gjteng@vip.sina.com; Zhu Guangyu [Department of Radiology, Zhong-Da Hospital, Southeast University, 87 Dingjiaqiao Road, Nanjing 210009 (China); He Shicheng [Department of Radiology, Zhong-Da Hospital, Southeast University, 87 Dingjiaqiao Road, Nanjing 210009 (China); Deng Gang [Department of Radiology, Zhong-Da Hospital, Southeast University, 87 Dingjiaqiao Road, Nanjing 210009 (China); He Jie [Department of Radiology, Zhong-Da Hospital, Southeast University, 87 Dingjiaqiao Road, Nanjing 210009 (China)

2007-02-15

Objective: To evaluate technical feasibility and acute and subacute radiotolerance of a self-expandable stent loaded with {sup 125}I seeds in the rabbit esophagus. Methods: A self-expandable stent designed for esophageal application was made of 0.16 mm nitinol wire and loaded with {sup 125}I seeds (CIAE-6711). Twenty-seven stents with three different radioactive dosages (n = 9 in each dosage group) were implanted in the esophagus of healthy rabbits, while nine stents alone were used as controls. The stents were perorally deployed into the esophagus under fluoroscopic guidance. Radiological follow-up included plain chest film, CT scan, and barium esophagography which were undertaken in all rabbits of each group at 2, 4, and 8 weeks, respectively, which were correlated to histopathological findings. The stented esophageal segments along with their adjacent tissues were harvested for histopathological examinations. Results: The stent was successfully deployed into the targeted esophageal segment in all rabbits. Neither {sup 125}I seeds dislodged from the stent during the deployment, nor they did during the follow-up period. The greatest (16.2 Gy) absorbed dose was found in the tissue 10 mm from {sup 125}I seeds at 8 weeks. Slight epithelial hyperplasia on the stent surface and submucosal inflammatory process developed at 2 weeks, which reached the peak at 8 weeks after the procedure. Significant thickness of the esophageal muscular layer was found at 8 weeks only in the groups with {sup 125}I seeds. On radiologic follow-up, moderate strictures on both ends of the stents developed at 4 weeks and became severe at 8 weeks after the procedure in all groups. Conclusion: Deployment of a self-expandable stent loaded with {sup 125}I seeds is technically feasible and safe within the first 8 weeks. Acute and subacute radiotolerance of the treated esophagus and its adjacent tissues by {sup 125}I seeds is well preserved in a healthy rabbit model.

Experimental Study of Heat Energy Absorber with Porous Medium for Thermoelectric Conversion System

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Tzer-Ming Jeng

2013-12-01

Full Text Available The thermoelectric conversion system usually consists of the heat absorber, the thermoelectric generator (TEG and the heat sink, while the heat absorber collects the heat to increase the temperature on the hot surface of TEG and enhances the generating electricity. This study experimentally investigated the performance of the brass-beads packed-bed heat absorber for the thermoelectric conversion system. The packed-bed heat absorber is installed in a square channel with the various flow orientation systems and the small ratio of channel width to bead diameter. The flow orientation systems included the straight flow and jet flow systems. This study showed the local and average heat transfer characteristics for various parameters. The experimental results can be the base of designs for the novel porous heat absorber of the thermoelectric conversion system.

Comparison of self-expandable and balloon-expanding stents for hybrid ductal stenting in hypoplastic left heart complex.

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Goreczny, Sebastian; Qureshi, Shakeel A; Rosenthal, Eric; Krasemann, Thomas; Nassar, Mohamed S; Anderson, David R; Morgan, Gareth J

2017-07-01

We aimed to compare the procedural and mid-term performance of a specifically designed self-expanding stent with balloon-expandable stents in patients undergoing hybrid palliation for hypoplastic left heart syndrome and its variants. The lack of specifically designed stents has led to off-label use of coronary, biliary, or peripheral stents in the neonatal ductus arteriosus. Recently, a self-expanding stent, specifically designed for use in hypoplastic left heart syndrome, has become available. We carried out a retrospective cohort comparison of 69 neonates who underwent hybrid ductal stenting with balloon-expandable and self-expanding stents from December, 2005 to July, 2014. In total, 43 balloon-expandable stents were implanted in 41 neonates and more recently 47 self-expanding stents in 28 neonates. In the balloon-expandable stents group, stent-related complications occurred in nine patients (22%), compared with one patient in the self-expanding stent group (4%). During follow-up, percutaneous re-intervention related to the ductal stent was performed in five patients (17%) in the balloon-expandable stent group and seven patients (28%) in self-expanding stents group. Hybrid ductal stenting with self-expanding stents produced favourable results when compared with the results obtained with balloon-expandable stents. Immediate additional interventions and follow-up re-interventions were similar in both groups with complications more common in those with balloon-expandable stents.

Future developments in biliary stenting

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Hair CD

2013-06-01

Full Text Available Clark D Hair,1 Divyesh V Sejpal21Department of Medicine, Section of Gastroenterology and Hepatology, Baylor College of Medicine, Houston, TX, USA; 2Department of Medicine, Section of Gastroenterology, Hofstra North Shore-LIJ School of Medicine, North Shore University Hospital, Manhasset, NY, USAAbstract: Biliary stenting has evolved dramatically over the past 30 years. Advancements in stent design have led to prolonged patency and improved efficacy. However, biliary stenting is still affected by occlusion, migration, anatomical difficulties, and the need for repeat procedures. Multiple novel plastic biliary stent designs have recently been introduced with the primary goals of reduced migration and improved ease of placement. Self-expandable bioabsorbable stents are currently being investigated in animal models. Although not US Food and Drug Administration approved for benign disease, fully covered self-expandable metal stents are increasingly being used in a variety of benign biliary conditions. In malignant disease, developments are being made to improve ease of placement and stent patency for both hilar and distal biliary strictures. The purpose of this review is to describe recent developments and future directions of biliary stenting.Keywords: plastic stents, self-expandable metal stents, drug eluting stents, bioabsorbable stents, malignant biliary strictures, benign biliary strictures

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

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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.

Wingspan stent system in the treatment of symptomatic intracranial atherosclerotic stenosis

International Nuclear Information System (INIS)

Li Tianxiao; Li Zhaoshuo; Wang Ziliang; Xue Jiangyu; Bai Weixing; Li Li; Zhai Shuiting; Feng Yingpu

2010-01-01

Objective: To assess the safety, feasibility, short- and mid-term efficacy of wingspan stent for treating patients with symptomatic intracranial artery stenosis. Methods: A total of 113 patients with severe symptomatic intracranial stenosis were enrolled and Gateway-wingspan stenting were performed on all patients. The technical success, the pre- and post-stenting stenosis, perioperative complications, clinical outcome and restenosis rates were recorded, and chi-square test was used for analysis of complication rate by comparing our results with the results of Warfarin-Aspirin Symptomatic Intracranial Disease (WASID) study and NIH multi-center Wingspan stenting trial. Results: The technical success rate was 99.1% (112/ 113). The mean pre and post-stent stenoses were (80.7±9.3)% and (27.7±9.7)% (χ 2 =9.397, P<0.05). The total complication rate was 4.4% (5/113) during the follow-up (mean 14.5 months, range 1-28 months), and the frequency of' restenosis was 12.5% (5/40) at 6 months. The primary endpoint events, ischemic stroke, and lesion-related ischemic stroke were lower in our study (4.5%, 3.5%, 3.5%) compared with the results of WASID trial (21.1%, 20.4%, 15.0%, P<0.05). For those with poor outcome in the three high-risk sub-groups which were with more than 70% stenosis, or last event from the treatment was less than 17 days, or NIHSS was above 1, a better outcome was observed in our group (4.5%, 4.7% and 2.0% in our study, 19.0%, 17.0% and 19.6% in previous study, P<0.05). The medium-term efficacy in this group (4.5%) significantly improved compared with NIH study (14.0%, P< 0.05). Conclusions: Wingspan stenting for symptomatic intracranial arterial stenosis is with good safety, feasibility and low perioperative stroke rate and mortality. The incidence of primary endpoint events and the ischemic events are lower than those of medication group, and the efficacy of stenting is significantly better than medication even in high-risk population. (authors)

Self-expandable metallic stents vs. plastic stents for endoscopic biliary drainage in hepatocellular carcinoma.

Science.gov (United States)

Chung, Kwang Hyun; Lee, Sang Hyub; Park, Jin Myung; Lee, Jae Min; Ahn, Dong-Won; Ryu, Ji Kon; Kim, Yong-Tae

2015-06-01

The patency of self-expandable metallic stents (SEMS) is known to be better than plastic stents in the palliation of malignant biliary obstruction. However, data are scarce for obstructive jaundice caused by hepatocellular carcinoma (HCC). This study aimed to compare SEMSs and plastic stents for the palliation of obstructive jaundice in unresectable HCC. A total of 96 patients who underwent endoscopic retrograde biliary drainage with SEMSs or plastic stents were included in this retrospective analysis. The rate of successful biliary drainage, adverse events, stent patency duration, and patient survival were compared between the SEMS (n = 36) and plastic stent (n = 60) groups. The rate of successful biliary drainage was similar between the SEMS and plastic stent groups (25/36 [69.4 %] vs. 39/60 [65.0 %]; P = 0.655). Adverse events occurred in 6 patients (16.7 %) in the SEMS group and 13 patients (21.7 %) in the plastic stent group (P = 0.552). The median patency duration was also similar between the two groups (60 vs. 68 days; P = 0.396). The median patient survival was longer in the plastic stent group than in the SEMS group (123 vs. 48 days; P = 0.005). SEMSs were not superior to plastic stents for the palliation of malignant biliary obstruction in HCC with regard to successful drainage, stent patency, and adverse events. Patient survival was better in the plastic stent group. Given the lower cost, plastic stents could be a favorable option for malignant biliary obstruction caused by HCC. © Georg Thieme Verlag KG Stuttgart · New York.

Mechanical properties of various z-stent designs: an endovascular stent-grafting perspective.

Science.gov (United States)

Bashar, Abul Hasan Muhammad; Kazui, Teruhisa; Washiyama, Naoki; Terada, Hitoshi; Yamashita, Katsushi; Haque, Mohammad E

2003-08-01

To comparatively assess the mechani-cal behavior of various clinically relevant Z-stent designs. A total of 16 Z-stents of original, biliary, spiral, and double-skirted designs (n=4 for each) were constructed using similar specifications for all. Stents were then evaluated for stiffness, snap opening force (SOF), flexibility, and displacement force using a novel tensiometer. Differences among the stents were determined using statistical methods. Stents explanted from dog aorta after a mean follow-up of 13 months were examined under a scanning electron microscope for surface defects. Forces required for about 50% reduction in diameter were 1.88 +/- 0.16 N, 3.81 +/- 0.21 N, 2.76 +/- 0.22 N, and 3.35 +/- 0.19 N for original, biliary, spiral, and skirted designs, respectively. Differences among the four designs were statistically significant at almost all points of measurement (P designs showed higher SOF values in the early measurements. Stents explanted from dog aorta after a mean duration of 13 months showed no obvious corrosion or breakage in the wire struts. Significant differences exist among the various Z-stent designs in terms of their mechanical properties. Understanding them should help to select the appropriate stent for a given lesion. 316L stainless steel shows a favorable long-term tissue interaction.

Stent thrombosis with drug-eluting and bare-metal stents: evidence from a comprehensive network meta-analysis.

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Palmerini, Tullio; Biondi-Zoccai, Giuseppe; Della Riva, Diego; Stettler, Christoph; Sangiorgi, Diego; D'Ascenzo, Fabrizio; Kimura, Takeshi; Briguori, Carlo; Sabatè, Manel; Kim, Hyo-Soo; De Waha, Antoinette; Kedhi, Elvin; Smits, Pieter C; Kaiser, Christoph; Sardella, Gennaro; Marullo, Antonino; Kirtane, Ajay J; Leon, Martin B; Stone, Gregg W

2012-04-14

The relative safety of drug-eluting stents and bare-metal stents, especially with respect to stent thrombosis, continues to be debated. In view of the overall low frequency of stent thrombosis, large sample sizes are needed to accurately estimate treatment differences between stents. We compared the risk of thrombosis between bare-metal and drug-eluting stents. For this network meta-analysis, randomised controlled trials comparing different drug-eluting stents or drug-eluting with bare-metal stents currently approved in the USA were identified through Medline, Embase, Cochrane databases, and proceedings of international meetings. Information about study design, inclusion and exclusion criteria, sample characteristics, and clinical outcomes was extracted. 49 trials including 50,844 patients randomly assigned to treatment groups were analysed. 1-year definite stent thrombosis was significantly lower with cobalt-chromium everolimus eluting stents (CoCr-EES) than with bare-metal stents (odds ratio [OR] 0·23, 95% CI 0·13-0·41). The significant difference in stent thrombosis between CoCr-EES and bare-metal stents was evident as early as 30 days (OR 0·21, 95% CI 0·11-0·42) and was also significant between 31 days and 1 year (OR 0·27, 95% CI 0·08-0·74). CoCr-EES were also associated with significantly lower rates of 1-year definite stent thrombosis compared with paclitaxel-eluting stents (OR 0·28, 95% CI 0·16-0·48), permanent polymer-based sirolimus-eluting stents (OR 0·41, 95% CI 0·24-0·70), phosphorylcholine-based zotarolimus-eluting stents (OR 0·21, 95% CI 0·10-0·44), and Resolute zotarolimus-eluting stents (OR 0·14, 95% CI 0·03-0·47). At 2-year follow-up, CoCr-EES were still associated with significantly lower rates of definite stent thrombosis than were bare-metal (OR 0·35, 95% CI 0·17-0·69) and paclitaxel-eluting stents (OR 0·34, 95% CI 0·19-0·62). No other drug-eluting stent had lower definite thrombosis rates compared with bare

Comparison of a New Polytetrafluoroethylene-Covered Metallic Stent to a Noncovered Stent in Canine Ureters

International Nuclear Information System (INIS)

Chung, Hwan-Hoon; Lee, Seung Hwa; Cho, Sung Bum; Park, Hong Suk; Kim, Young Sik; Kang, Byung Chul; Frisoli, Joan K.; Razavi, Mahmood K.

2008-01-01

The aim of this study was to determine the feasibility of using a newly designed polytetrafluoroethylene (PTFE)-covered metallic stent in the ureter by comparing its effectiveness with that of the noncovered stent in a canine model. We placed 14 stents in the ureters of seven mongrel dogs that weighed 30-40 kg each. The covered and noncovered stents were deployed in the right and left ureters, respectively, of six dogs. In the seventh dog, a covered stent and a double-J catheter were inserted in the right ureter, and a covered stent only was inserted in the left ureter. The first six dogs were sacrificed at 5, 10, and 15 weeks after deployment of the stents (two for each follow-up period), and the seventh dog was sacrificed at 30 weeks. There was no migration or poor expansion of any of the stents observed on plain radiography. On intravenous pyelogram and retrograde pyelogram, all of the covered stents at each follow-up period had patent lumens at the stented segments without hydronephrosis, and the passage of contrast material through it was well preserved. The noncovered stents in the dogs sacrificed at 5 and 10 weeks and one of the two dogs sacrificed at 15 weeks showed near-complete occlusion of the stent lumen due to ingrowth of the soft tissue, and severe hydronephrosis was also noted. The noncovered stent in the other dog sacrificed at 15 weeks showed the passage of contrast material without hydronephrosis, but the lumen of the stent was still nearly occluded by the soft tissue. There was no evidence of hydronephrosis or passage disturbance of the contrast material in both ureters of the dog sacrificed at 30 weeks. We conclude that the newly designed PTFE-covered stent effectively prevented the luminal occlusion caused by urothelial hyperplasia compared to the near-total occlusion of the noncovered stents, and no migration of the covered stents was noted

Treatment of Post-Stent Gastroesophageal Reflux by Anti-Reflux Z-Stent

International Nuclear Information System (INIS)

Davies, Roger Philip; Kew, Jacqueline; Byrne, Peter D.

2000-01-01

Severe symptoms of heartburn and retrosternal pain consistent with gastro-esophageal reflux (GER) developed in a patient following placement of a conventional self-expanding 16-24-mm-diameter x 12-cm-long esophageal stent across the gastroesophageal junction to treat an obstructing esophageal carcinoma. A second 18-mm-diameter x 10-cm-long esophageal stent with anti-reflux valve was deployed coaxially and reduced symptomatic GER immediately. Improvement was sustained at 4-month follow-up. An anti-reflux stent can be successfully used to treat significant symptomatic GER after conventional stenting

RESEARCH ABSORBING STATES OF THE SYSTEM USING MARKOV CHAINS AND FUNDAMENTAL MATRIX

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Тетяна Мефодіївна ОЛЕХ

2016-02-01

Full Text Available The article discusses the use Markov chains to research models that reflect the essential properties of systems, including methods of measuring the parameters of projects and assess their effectiveness. In the study carried out by its decomposition system for certain discrete state and create a diagram of transitions between these states. Specificity displays various objects Markov homogeneous chains with discrete states and discrete time determined by the method of calculation of transition probabilities. A model of success criteria for absorbing state system that is universal for all projects. A breakdown of passages to the matrix submatrices. The variation elements under matrix Q n with growth linked to the definition of important quantitative characteristics of absorbing circuits: 1 the probability of achieving the status of absorbing any given; 2 the mean number of steps needed to achieve the absorbing state; 3 the mean time that the system spends in each state to hit irreversible system in absorbing state. Built fundamental matrix that allowed calculating the different characteristics of the system. Considered fundamental matrix for supposedly modeled absorbing Markov chain, which gives the forecast for the behavior of the system in the future regardless of the absolute value of the time elapsed from the starting point. This property illustrates the fundamental matrix Markov process that characterizes it as a process without aftereffect.

Surgical stent for dental implant using cone beam CT images

International Nuclear Information System (INIS)

Choi, Hyung Soo; Kim, Gyu Tae; Choi, Yong Suk; Hwang, Eui Hwan

2010-01-01

The purpose of this study is to develop a surgical stent for dental implant procedure that can be easily applied and affordable by using cone beam computerized tomography (CBCT). Aluminum, Teflon-PFA (perfluoroalkoxy), and acetal (polyoxymethylene plastic) were selected as materials for the surgical stent. Among these three materials, the appropriate material was chosen using the CBCT images. The surgical stent, which could be easily placed into an oral cavity, was designed with chosen material. CBCT images of the new surgical stent on mandible were obtained using Alphard-3030 dental CT system (Asahi Roentgen Co., Ltd., Kyoto, Japan). The point of insertion was prescribed on the surgical stent with the multiplanar reconstruction software of OnDemand3D (CyberMed Inc., Seoul, Korea). Guide holes were made at the point of insertion on the surgical stent using newly designed guide jig. CBCT scans was taken for the second time to verify the accuracy of the newly designed surgical stent. Teflon-PFA showed radiologically excellent image characteristics for the surgical stent. High accuracy and reproducibility of implantation were confirmed with the surgical stent. The newly designed surgical stent can lead to the accurate implantation and achieve the clinically predictable result.

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

Science.gov (United States)

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

2014-12-20

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

Determination of the Absorbed Doses in Shanks of Interventional Radiologists

International Nuclear Information System (INIS)

Golnik, N.; Szczepanski, K.; Tulik, P.; Obryk, B.

2008-01-01

Complicated procedures of interventional radiology require usually a much longer investigation time, comparing to the conventional radiography. Moreover, interventional radiology procedures require the presence of the medical staff next to the patient in order to perform the procedure. This results in higher risk for health professionals. Even though these persons reasonably keep away from the primary X ray beam, they are under the effects of scatter radiation due to the interaction of the primary beam with the patient. The protection aprons, thyroid protectors and shielding glasses are used in order to minimize the doses for the staff, but lower parts of legs remain usually unprotected and the absorbed doses in shanks are not recorded. The paper presents the measured values of the absorbed dose in lower extremities of medical staff, involved in the procedures of interventional radiology, completed with the measurements of air kerma under the patient table. Measurements were performed in one of big hospitals in Warsaw during all the procedures performed in six weeks. Majority of the procedures constituted angioplasty or angioplasty with vascular stenting, uterine fibroid embolization and cholangiography. In the angioplasty procedure, imaging techniques are used to guide a balloon-tipped catheter into an artery and advance it to where the vessel is narrow or blocked. The balloon is then inflated to open the vessel, deflated and removed. In vascular stenting, which is often performed with angioplasty, a small wire mesh tube (a stent) is permanently placed in the newly opened artery to help it remain open. In a uterine fibroid embolization procedure, the image guidance is used in order to place an embolic agent (synthetic material) inside one or more of the blood vessels that supply the fibroid tumors with blood. As a result, these vessels become occluded, or closed off, and the fibroid tissue shrinks. Percutaneous transhepatic cholangiography is a way of examining

Self-expandable metalic endotracheal stent

International Nuclear Information System (INIS)

Do, Young Soo; Cho, Dae Soon; Cho, Kyung Ja; Lee, Young Soo; Lee, Mi Jae

1993-01-01

Six bare stents and six covered stents were inserted in the trachea of 12 dogs under general anesthesia. After 1-10 weeks of observation, the dogs were killed, and the trachea and lung were examined grossly and histologically. Pneumonia and stent migration were observed more frequently at covered stent group. Inflammatory change of the trachea was more severe at covered stent group. In conclusion, we believe that it is inadequate to insert silicone covered stent in the tracheobronchial tree. (Author)

Self-expandable metalic endotracheal stent

Energy Technology Data Exchange (ETDEWEB)

Do, Young Soo; Cho, Dae Soon; Cho, Kyung Ja; Lee, Young Soo; Lee, Mi Jae [Korea Cancer Center Hospital, Seoul (Korea, Republic of)

1993-01-01

Six bare stents and six covered stents were inserted in the trachea of 12 dogs under general anesthesia. After 1-10 weeks of observation, the dogs were killed, and the trachea and lung were examined grossly and histologically. Pneumonia and stent migration were observed more frequently at covered stent group. Inflammatory change of the trachea was more severe at covered stent group. In conclusion, we believe that it is inadequate to insert silicone covered stent in the tracheobronchial tree. (Author).

Treatment of Complete and Partial Obstruction of the Nasolacrimal System with Polyurethane Stents: Initial Experience

International Nuclear Information System (INIS)

Pulido-Duque, Juan M.; Reyes, Ricardo; Carreira, Jose M.; Vega, Francisco; Gorriz, Elias; Pardo, M. Dolores; Perez, Francisco; Maynar, Manuel

1998-01-01

Purpose: To present our experience in the treatment of nasolacrimal occlusion by means of polyurethane stents. Methods: Forty polyurethane stents were placed under fluoroscopic guidance in 35 consecutive patients with epiphora due to total or partial obstruction of the nasolacrimal system. The set designed by Song was used in all patients. The procedure was performed by introducing a guidewire through the superior punctum into the canaliculus and advancing it across the obstruction into the inferior meatus of the nasal cavity. After pulling out the guidewire, the stent was advanced in retrograde fashion and released into the sac and the nasolacrimal duct.Results: The technical success rate was 100%. The average time for the procedure was 25 min (range 10-60 min). Immediate complications were: mild pain (n= 5), severe pain (n= 1), minimal epistaxis (n= 7), and moderate epistaxis (n= 1). No major complications occurred. The last clinical control revealed complete resolution of epiphora in 35 eyes and partial resolution in four; one patient did not improve. Conclusion: This technique for treatment of obstruction of the nasolacrimal system is simple and safe, and may obviate the use of more invasive procedures

Shock absorber system for nuclear reactor ice condenser compartment

International Nuclear Information System (INIS)

Meier, J.F.; Rudd, G.E.; Pradhan, A.V.; George, J.A.; Lippincott, H.W.; Sutherland, J.D.

1979-01-01

A shock absorber system was designed to absorb the energy imparted to doors in a nuclear reactor ice condenser compartment as they swing rapidly to an open position. Each shock absorber which is installed on a wall adjacent to each door is large and must absorb up to about 40,000 foot pounds of energy. The basic shock absorber component comprises foam enclosed in a synthetic fabric bag having a volume about twice the foam volume. A stainless steel knitted mesh bag of the same volume as the fabric bag, contains the fabric bag and its enclosed foam. To protect the foam and bags during construction activities at the reactor site and from the shearing action of the doors, a protective sheet metal cover is installed over the shock absorber ends and the surface to be contacted by the moving door. With the above shock absorber mounted on a wall behind each door, as the door is forcibly opened by steam pressure and air resulting from a pipe break in the reactor compartment, it swings at a high velocity into contact with the shock absorber, crushes the foam and forces it into the fabric bag excess material thus containing the foam fragmented particles, and minimizes build-up of pressure in the bag as a result of the applied compressive force

Efficacy and Safety of the Absorb Everolimus-Eluting Bioresorbable Scaffold for Treatment of Patients With Diabetes Mellitus: Results of the Absorb Diabetic Substudy.

Science.gov (United States)

Kereiakes, Dean J; Ellis, Stephen G; Kimura, Takeshi; Abizaid, Alexandre; Zhao, Weiying; Veldhof, Susan; Vu, Minh-Thien; Zhang, Zhen; Onuma, Yoshinobu; Chevalier, Bernard; Serruys, Patrick W; Stone, Gregg W

2017-01-09

The study sought to evaluate the efficacy and safety of the Absorb everolimus-eluting bioresorbable vascular scaffold (BVS) (Abbott Vascular, Abbott Park, Illinois) in patients with diabetes mellitus. Randomized, controlled trials have demonstrated comparable clinical outcomes following percutaneous coronary intervention with either Absorb BVS or metallic Xience everolimus-eluting stent. However, these trials lack power required to provide reliable treatment effect estimates in this high-risk population. In a pre-specified, powered analysis, patients with diabetes who received ≥1 Absorb were pooled from the ABSORB II, III, and JAPAN randomized trials and from the single arm ABSORB EXTEND registry. The study composite primary endpoint was target lesion failure (TLF) at 1 year following Absorb BVS compared with a performance goal of 12.7%. Among 754 diabetic patients included in analysis (27.3% insulin treated), the 1-year TLF rate was 8.3% (upper 1-sided 95% confidence limit: 10.1%; p = 0.0001 vs. performance goal). Scaffold thrombosis (definite or probable) was observed in 2.3% of patients. Multivariable regression identified older age, insulin treatment, and smaller pre-procedure reference vessel diameter as significant independent predictors of 1-year TLF. The Absorb diabetic substudy suggests efficacy and safety of the Absorb BVS for treatment of patients with diabetes mellitus. Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Experimental comparison study of the tissue characteristics in transjugular intrahepatic portosystemic shunt and vascular stent

International Nuclear Information System (INIS)

Lu Qin; An Yanli; Deng Gang; Fang Wen; Zhu Guangyu; Niu Huanzhang; Yu Hui; Li Guozhao; Teng Gaojun; Wang Zhen; Wei Xiaoying

2009-01-01

Objective: To investigate the tissue characteristics within vascular stent and transjugular intrahepatic portosystemic shunt(TIPS) on swine and to provide more information for the understanding and prevention of vascular stent and TIPS restenosis. Methods: Animal models for TIPS were built in 6 swine and vascular stents were implanted in iliac veins simultaneously. 14-28 days after the operation, the 6 swine were killed to remove the TIPS and vascular stent and the pathological examinations were performed on the tissues within the shunt and stent. The similarities and differences of the tissues within the shunt and stent were analyzed with Krttskal Wallis test. Results: Restenosis of TIPS occurred in 4 models and complete occlusion were seen in 2, while all vascular stents were patent and coated with a thin layer of intimal tissue. Electron microscopic results showed that the tissues in restenotic TIPS were loose and with more extra matrix and fibers, and less smooth muscle, fibroblastic and myofibroblastic cells with different and irregular shape and rich secretory granules. The tissues in patent TIPS contained more extra fibers, smooth muscle and fibroblastic cells with normal organelle. The intimal tissues in vascular stent contained more fibers and fibroblasts cells, less smooth muscle cells. On immunohistochemical staining, the tissues in restenotic and patent TIPS as well as the intimal tissues in vascular stent had strong positive expression for anti-SMC- actin-α, the expression were gradually weakened for PCNA, the intimal tissues in vascular stent had a strong positive expression for vimentin, while the expression of the tissues in restenotic and patent TIPS were weakened gradually. For myoglobulin, the tissues in restenotic TIPS had weakly positive expression, the expression in patent TIPS and vascular stent were almost negative. Western blot results for TGF-β showed that the absorbance ratios of the intima tissues in vascular stent, normal vascular

Predictive factors for the failure of endoscopic stent-in-stent self-expandable metallic stent placement to treat malignant hilar biliary obstruction.

Science.gov (United States)

Sugimoto, Mitsuru; Takagi, Tadayuki; Suzuki, Rei; Konno, Naoki; Asama, Hiroyuki; Watanabe, Ko; Nakamura, Jun; Kikuchi, Hitomi; Waragai, Yuichi; Takasumi, Mika; Sato, Yuki; Hikichi, Takuto; Ohira, Hiromasa

2017-09-14

To investigate the factors predictive of failure when placing a second biliary self-expandable metallic stents (SEMSs). This study evaluated 65 patients with an unresectable malignant hilar biliary obstruction who were examined in our hospital. Sixty-two of these patients were recruited to the study and divided into two groups: the success group, which consisted of patients in whom a stent-in-stent SEMS had been placed successfully, and the failure group, which consisted of patients in whom the stent-in-stent SEMS had not been placed successfully. We compared the characteristics of the patients, the stricture state of their biliary ducts, and the implemented endoscopic retrograde cholangiopancreatography (ERCP) procedures between the two groups. The angle between the target biliary duct stricture and the first implanted SEMS was significantly larger in the failure group than in the success group. There were significantly fewer wire or dilation devices (ERCP catheter, dilator, or balloon catheter) passing the first SEMS cell in the failure group than in the success group. The cut-off value of the angle predicting stent-in-stent SEMS placement failure was 49.7 degrees according to the ROC curve (sensitivity 91.7%, specificity 61.2%). Furthermore, the angle was significantly smaller in patients with wire or dilation devices passing the first SEMS cell than in patients without wire or dilation devices passing the first SEMS cell. A large angle was identified as a predictive factor for failure of stent-in-stent SEMS placement.

Future developments in biliary stenting

Science.gov (United States)

Hair, Clark D; Sejpal, Divyesh V

2013-01-01

Biliary stenting has evolved dramatically over the past 30 years. Advancements in stent design have led to prolonged patency and improved efficacy. However, biliary stenting is still affected by occlusion, migration, anatomical difficulties, and the need for repeat procedures. Multiple novel plastic biliary stent designs have recently been introduced with the primary goals of reduced migration and improved ease of placement. Self-expandable bioabsorbable stents are currently being investigated in animal models. Although not US Food and Drug Administration approved for benign disease, fully covered self-expandable metal stents are increasingly being used in a variety of benign biliary conditions. In malignant disease, developments are being made to improve ease of placement and stent patency for both hilar and distal biliary strictures. The purpose of this review is to describe recent developments and future directions of biliary stenting. PMID:23837001

Integration of regenerative shock absorber into vehicle electric system

Science.gov (United States)

Zhang, Chongxiao; Li, Peng; Xing, Shaoxu; Kim, Junyoung; Yu, Liangyao; Zuo, Lei

2014-03-01

Regenerative/Energy harvesting shock absorbers have a great potential to increase fuel efficiency and provide suspension damping simultaneously. In recent years there's intensive work on this topic, but most researches focus on electricity extraction from vibration and harvesting efficiency improvement. The integration of electricity generated from regenerative shock absorbers into vehicle electric system, which is very important to realize the fuel efficiency benefit, has not been investigated. This paper is to study and demonstrate the integration of regenerative shock absorber with vehicle alternator, battery and in-vehicle electrical load together. In the presented system, the shock absorber is excited by a shaker and it converts kinetic energy into electricity. The harvested electricity flows into a DC/DC converter which realizes two functions: controlling the shock absorber's damping and regulating the output voltage. The damping is tuned by controlling shock absorber's output current, which is also the input current of DC/DC converter. By adjusting the duty cycles of switches in the converter, its input impedance together with input current can be adjusted according to dynamic damping requirements. An automotive lead-acid battery is charged by the DC/DC converter's output. To simulate the working condition of combustion engine, an AC motor is used to drive a truck alternator, which also charges the battery. Power resistors are used as battery's electrical load to simulate in-vehicle electrical devices. Experimental results show that the proposed integration strategy can effectively utilize the harvested electricity and power consumption of the AC motor is decreased accordingly. This proves the combustion engine's load reduction and fuel efficiency improvement.

Progress on the MICE Liquid Absorber Cooling and Cryogenic Distribution System

International Nuclear Information System (INIS)

Green, M.A.; Baynham, E.; Bradshaw, T.; Drumm, P.; Ivanyushenkov, Y.; Ishimoto, S.; Cummings, M.A.C.; Lau, W.W.; Yang, S.Q.

2005-01-01

This report describes the progress made on the design of the cryogenic cooling system for the liquid absorber for the international Muon Ionization Cooling Experiment (MICE). The absorber consists of a 20.7-liter vessel that contains liquid hydrogen (1.48 kg at 20.3 K) or liquid helium (2.59 kg at 4.2 K). The liquid cryogen vessel is located within the warm bore of the focusing magnet for the MICE. The purpose of the magnet is to provide a low beam beta region within the absorber. For safety reasons, the vacuum vessel for the hydrogen absorber is separated from the vacuum vessel for the superconducting magnet and the vacuum that surrounds the RF cavities or the detector. The absorber thin windows separate the liquid in the absorber from the absorber vacuum. The absorber vacuum vessel also has thin windows that separate the absorber vacuum space from adjacent vacuum spaces. Because the muon beam in MICE is of low intensity, there is no beam heating in the absorber. The absorber can use a single 4 K cooler to cool either liquid helium or liquid hydrogen within the absorber

An experimental study of an energy absorbing restrainer for piping systems

International Nuclear Information System (INIS)

Sone, A.; Suzuki, K.

1989-01-01

Recently, in the seismic design methodology of the piping systems in nuclear power plants, new and improved design criteria and calculation techniques which will lead to more reliable and cost saving design products have been investigated. For instance, problems for reducing the snubbers in nuclear power plants which provide high costs for their inspections and maintenances and related flexible design problems for the dynamic piping systems have been investigated. Thus, in order to replace snubbers, various types of alternative supporting devices such as dynamic absorbers, gapped support and energy absorbing support devices have been proposed. A number of energy absorbing restrainers have been designed in Japan and United-States by allowing yield to occur during strong earthquakes. Advantages and disadvantages of these restrainers were examined analytically and experimentally. In order to overcome the disadvantages, the authors introduced new absorbing material LSPZ (laminated super plastic zinc) in which SPZ is expected to have reliable ductility and also efficient energy absorbability still under the normal temperature condition. This paper is devoted to an experimental works for this updated absorbing restrainer

Endothelial cell repopulation after stenting determines in-stent neointima formation: effects of bare-metal vs. drug-eluting stents and genetic endothelial cell modification.

Science.gov (United States)

Douglas, Gillian; Van Kampen, Erik; Hale, Ashley B; McNeill, Eileen; Patel, Jyoti; Crabtree, Mark J; Ali, Ziad; Hoerr, Robert A; Alp, Nicholas J; Channon, Keith M

2013-11-01

Understanding endothelial cell repopulation post-stenting and how this modulates in-stent restenosis is critical to improving arterial healing post-stenting. We used a novel murine stent model to investigate endothelial cell repopulation post-stenting, comparing the response of drug-eluting stents with a primary genetic modification to improve endothelial cell function. Endothelial cell repopulation was assessed en face in stented arteries in ApoE(-/-) mice with endothelial-specific LacZ expression. Stent deployment resulted in near-complete denudation of endothelium, but was followed by endothelial cell repopulation, by cells originating from both bone marrow-derived endothelial progenitor cells and from the adjacent vasculature. Paclitaxel-eluting stents reduced neointima formation (0.423 ± 0.065 vs. 0.240 ± 0.040 mm(2), P = 0.038), but decreased endothelial cell repopulation (238 ± 17 vs. 154 ± 22 nuclei/mm(2), P = 0.018), despite complete strut coverage. To test the effects of selectively improving endothelial cell function, we used transgenic mice with endothelial-specific overexpression of GTP-cyclohydrolase 1 (GCH-Tg) as a model of enhanced endothelial cell function and increased NO production. GCH-Tg ApoE(-/-) mice had less neointima formation compared with ApoE(-/-) littermates (0.52 ± 0.08 vs. 0.26 ± 0.09 mm(2), P = 0.039). In contrast to paclitaxel-eluting stents, reduced neointima formation in GCH-Tg mice was accompanied by increased endothelial cell coverage (156 ± 17 vs. 209 ± 23 nuclei/mm(2), P = 0.043). Drug-eluting stents reduce not only neointima formation but also endothelial cell repopulation, independent of strut coverage. In contrast, selective targeting of endothelial cell function is sufficient to improve endothelial cell repopulation and reduce neointima formation. Targeting endothelial cell function is a rational therapeutic strategy to improve vascular healing and decrease neointima formation after stenting.

Endoscopic stent suture fixation for prevention of esophageal stent migration during prolonged dilatation for achalasia treatment.

Science.gov (United States)

Rieder, E; Asari, R; Paireder, M; Lenglinger, J; Schoppmann, S F

2017-04-01

The aim of this study is to compare endoscopic stent suture fixation with endoscopic clip attachment or the use of partially covered stents (PCS) regarding their capability to prevent stent migration during prolonged dilatation in achalasia. Large-diameter self-expanding metal stents (30 mm × 80 mm) were placed across the gastroesophageal junction in 11 patients with achalasia. Stent removal was scheduled after 4 to 7 days. To prevent stent dislocation, endoscopic clip attachment, endoscopic stent suture fixation, or PCS were used. The Eckardt score was evaluated before and 6 months after prolonged dilatation. After endoscopic stent suture fixation, no (0/4) sutured stent migrated. When endoscopic clips were used, 80% (4/5) clipped stents migrated (p = 0.02). Of two PCS (n = 2), one migrated and one became embedded leading to difficult stent removal. Technical adverse events were not seen in endoscopic stent suture fixation but were significantly correlated with the use of clips or PCS (r = 0.828, p = 0.02). Overall, 72% of patients were in remission regarding their achalasia symptoms 6 months after prolonged dilatation. Endoscopic suture fixation of esophageal stents but not clip attachment appears to be the best method of preventing early migration of esophageal stents placed at difficult locations such as at the naive gastroesophageal junction. © The Authors 2017. Published by Oxford University Press on behalf of International Society for Diseases of the Esophagus. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

A new technique for end-to-end ureterostomy in the rat, using an indwelling reabsorbable stent.

Science.gov (United States)

Carmignani, G; Farina, F P; De Stefani, S; Maffezzini, M

1983-01-01

The restoration of the continuity of the urinary tract represents one of the major problems in rat renal transplantation. End-to-end ureterostomy is the most physiologically effective technique; however, it involves noteworthy technical difficulties because of the extremely thin caliber of the ureter in the rat and the high incidence of postoperative hydronephrosis. We describe a new technique for end-to-end ureterostomy in the rat, where the use of an absorbable ureteral stent is recommended. A 5-0 plain catgut thread is used as a stent. The anastomosis is performed under an operating microscope at X 25-40 magnification with interrupted sutures of 11-0 Vicryl. The use of the indwelling stent facilitates the performance of the anastomosis and yields optimal results. The macroscopical, radiological, and histological controls in a group of rats operated on with this technique showed a very high percentage of success with no complications, a result undoubtedly superior to that obtained with conventional methods.

Drug-eluting stents and bare metal stents in patients with NSTE-ACS

DEFF Research Database (Denmark)

Pedersen, Sune Haahr; Pfisterer, Matthias; Kaiser, Christoph

2014-01-01

the randomised BASKET-PROVE trial (sirolimus-eluting stent vs. everolimus-eluting stent vs. bare metal stent in large-vessel stenting). The primary endpoint was the combined two-year rate of cardiovascular death or non-fatal myocardial infarction (MI). Secondary endpoints were each component of the primary...... implantation in large vessels was associated with a reduction in both TVR and the combined endpoint consisting of cardiovascular death/MI. Thus, DES use improves both efficacy and safety. These findings support the use of DES in NSTE-ACS patients....

Risk and timing of clinical events according to diabetic status of patients treated with everolimus-eluting bioresorbable vascular scaffolds versus everolimus-eluting stent: 2-year results from a propensity score matched comparison of ABSORB EXTEND and SPIRIT trials.

Science.gov (United States)

Campos, Carlos M; Caixeta, Adriano; Franken, Marcelo; Bartorelli, Antonio L; Whitbourn, Robert J; Wu, Chiung-Jen; Li Paul Kao, Hsien; Rosli, Mohd Ali; Carrie, Didier; De Bruyne, Bernard; Stone, Gregg W; Serruys, Patrick W; Abizaid, Alexandre

2018-02-15

to compare the occurrence of clinical events in diabetics treated with the Absorb bioresorbable vascular scaffold (Absorb BVS; Abbott Vascular, Santa Clara, CA) versus everolimus-eluting metal stents (EES; XIENCE V; Abbott Vascular, Santa Clara, CA) BACKGROUND: There are limited data dedicated to clinical outcomes of diabetic patients treated with bioresorbable scaffolds (BRS) at 2-year horizon. The present study included 812 patients in the ABSORB EXTEND study in which a total of 215 diabetic patients were treated with Absorb BVS. In addition, 882 diabetic patients treated with EES in pooled data from the SPIRIT clinical program (SPIRIT II, SPIRIT III and SPIRIT IV trials) were used for comparison by applying propensity score matching using 29 different variables. The primary endpoint was ischemia driven major adverse cardiac events (ID-MACE), including cardiac death, myocardial infarction (MI), and ischemia driven target lesion revascularization (ID-TLR). After 2 years, the ID-MACE rate was 6.5% in the Absorb BVS vs. 8.9% in the Xience group (P = 0.40). There was no difference for MACE components or definite/probable device thrombosis (HR: 1.43 [0.24,8.58]; P = 0.69). The occurrence of MACE was not different for both diabetic status (insulin- and non-insulin-requiring diabetes) in all time points up to the 2-year follow-up for the Absorb and Xience groups. In this largest ever patient-level pooled comparison on the treatment of diabetic patients with BRS out to two years, individuals with diabetes treated with the Absorb BVS had a similar rate of MACE as compared with diabetics treated with the Xience EES. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Risk factors for technical failure of endoscopic double self-expandable metallic stent placement by partial stent-in-stent method.

Science.gov (United States)

Kawakubo, Kazumichi; Kawakami, Hiroshi; Toyokawa, Yoshihide; Otani, Koichi; Kuwatani, Masaki; Abe, Yoko; Kawahata, Shuhei; Kubo, Kimitoshi; Kubota, Yoshimasa; Sakamoto, Naoya

2015-01-01

Endoscopic double self-expandable metallic stent (SEMS) placement by the partial stent-in-stent (PSIS) method has been reported to be useful for the management of unresectable hilar malignant biliary obstruction. However, it is technically challenging, and the optimal SEMS for the procedure remains unknown. The aim of this study was to identify the risk factors for technical failure of endoscopic double SEMS placement for unresectable malignant hilar biliary obstruction (MHBO). Between December 2009 and May 2013, 50 consecutive patients with MHBO underwent endoscopic double SEMS placement by the PSIS method. We retrospectively evaluated the rate of successful double SEMS placement and identified the risk factors for technical failure. The technical success rate for double SEMS placement was 82.0% (95% confidence interval [CI]: 69.2-90.2). On univariate analysis, the rate of technical failure was high in patients with metastatic disease and unilateral placement. Multivariate analysis revealed that metastatic disease was a significant risk factor for technical failure (odds ratio: 9.63, 95% CI: 1.11-105.5). The subgroup analysis after double guidewire insertion showed that the rate of technical success was higher in the laser-cut type SEMS with a large mesh and thick delivery system than in the braided type SEMS with a small mesh and thick delivery system. Metastatic disease was a significant risk factor for technical failure of double SEMS placement for unresectable MHBO. The laser-cut type SEMS with a large mesh and thin delivery system might be preferable for the PSIS procedure. © 2014 Japanese Society of Hepato-Biliary-Pancreatic Surgery.

Percutaneous placement of ureteral stent

Energy Technology Data Exchange (ETDEWEB)

Kim, Seung Hyup; Park, Jae Hyung; Han, Joon Koo; Han, Man Chung [Seoul National University College of Medicine, Seoul (Korea, Republic of)

1990-12-15

Antegrade placement of ureteral stents has successfully achieved in 41 of 46 ureters. When it was difficult to advance ureteral stents through the lesion, it was facilitated by retrograde guide-wire snare technique through urethra. Complications associated with the procedure were non-function of ureteral stent by occlusion, upward migration,and spontaneous fracture of ureteral stent. These complications were managed by percutaneous nephrostomy and removal of ureteral stents by guide-wire snare technique and insertion of a new ureteral stent. While blood cell in urine was markedly increased in about 50% of patients following the procedure.

Covered duodenal self-expandable metal stents prolong biliary stent patency in double stenting: The largest series of bilioduodenal obstruction.

Science.gov (United States)

Hori, Yasuki; Naitoh, Itaru; Hayashi, Kazuki; Kondo, Hiromu; Yoshida, Michihiro; Shimizu, Shuya; Hirano, Atsuyuki; Okumura, Fumihiro; Ando, Tomoaki; Jinno, Naruomi; Takada, Hiroki; Togawa, Shozo; Joh, Takashi

2018-03-01

Endoscopic biliary and duodenal stenting (DS; double stenting) is widely accepted as a palliation therapy for malignant bilioduodenal obstruction. The aim of the current study was to investigate the patency and adverse events of duodenal and biliary stents in patients with DS. Patients who underwent DS from April 2004 to March 2017 were analyzed retrospectively with regard to clinical outcomes and predictive factors of recurrent biliary and duodenal obstruction (recurrent biliary obstruction [RBO] and recurrent duodenal obstruction [RDO]). A total of 109 consecutive patients was enrolled. Technical success of DS was achieved in 108 patients (99.1%). Symptoms due to biliary and duodenal obstruction were improved in 89 patients (81.7%). RBO occurred in 25 patients (22.9%) and RDO in 13 (11.9%). The median times to RBO and RDO from DS were 87 and 76 days, respectively. Placement of a duodenal uncovered self-expandable metal stent (U-SEMS) was significantly associated with RBO in the multivariable analysis (P = 0.007). Time to RBO was significantly longer in the duodenal covered self-expandable metal stent group than in the U-SEMS group (P = 0.003). No predictive factors of RDO were detected, and duodenal stent type was not associated with the time to RDO (P = 0.724). Double stenting was safe and effective for malignant bilioduodenal obstruction. Duodenal U-SEMS is a risk factor for RBO. The covered self-expandable metal stent is the preferred type of duodenal SEMS in patients with DS (Clinical trial registration number: UMIN000027606). © 2017 Journal of Gastroenterology and Hepatology Foundation and John Wiley & Sons Australia, Ltd.

Implante de stent dentro de stent recém-implantado em ponte de veia safena para otimização do resultado angiográfico Stenting a stent in saphenous vein graft to optimize the angiographic result

Directory of Open Access Journals (Sweden)

Antonio Esteves Fº

1998-03-01

Full Text Available Mulher de 60 anos, com angina progressiva e revascularização do miocárdio, há oito anos, com ponte de veia safena para coronária direita e anastomose de artéria mamaria esquerda para artéria descendente anterior. Submetida a implante de stent Gianturco-Roubin II em terço proximal da ponte de veia safena para artéria coronária direita, com resultado insatisfatório pela persistência de lesão residual, provavelmente, decorrente de prolapso para dentro da luz de material aterosclerótico através dos coils. Foi implantado outro stent (Palmaz-Schatz biliar dentro do stent GRII com sucesso e ótimo resultado angiográfico. Um 2º stent Palmaz-Schatz biliar foi implantado em lesão distal no corpo da ponte, ultrapassando os dois stents, anteriormente implantados, com sucesso. Em algumas situações, implante de stent dentro de outro stent é recurso útil para otimização de resultado angiográfico do implante de um stent.A 60 year-old woman with progressive angina who had been submitted to saphenous bypass-graft to right coronary artery and a left mammary artery graft to anterior descending artery eight years previously, underwent implantation of a Gianturco Roubin II stent in the proximal third of the saphenous vein graft. The result was suboptimal by persistence of a residual stenosis probably due to prolapse of atherosclerotic material through the coil spaces. Another stent (Palmaz-Schatz biliar stent was implanted at the previously stented site with no residual stenosis. Another Palmaz-Schatz biliar stent was successfully implanted in the distal body of the graft to treat another lesion (passing through the previously stents without difficulty. Stenting a stent, in selected situations, is a useful tool to optimize the angiographic result of stent implantation.

Advances in Study of Absorbable Metal Stent in Coronary Artery%冠状动脉内可吸收金属支架的研究进展

Institute of Scientific and Technical Information of China (English)

刘艳青

2012-01-01

冠状动脉内支架植入是目前广泛应用的冠心病治疗手段,但支架内狭窄和晚期血栓形成影响冠状动脉支架远期疗效和安全性,长期应用抗血小板药物所带来的不良反应以及经济上给患者造成的负担,这些都限制了冠状动脉支架的进一步应用.生物可吸收金属支架具有与裸金属支架相当的支撑力及良好生物相容性,可有效降低再狭窄率和血栓形成,临床应用前景十分广阔.%Currently, coronary stents are widely used in the treatment of coronary heart disease. However, the major limitations of stents are in-stent restenosis and late thrombosis. These , which effect the long-term efficiency and safety of the stents. Moreover, prolonged antiplatelet therapy can have many adverse effects and economic burdens for a patient , and these factors limit the further development of stents. The use of a bioabsorbable metal stent which could provide the same mechanical properties compared to the bare metal stent and but with good bio-compatibility, could reduce the rate of restenosis and thrombosis. It owns a bright future in clinical coronary stents.

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

Science.gov (United States)

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

2016-02-14

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

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

Science.gov (United States)

Kasiri, Saeid; Kelly, Daniel J

2011-08-01

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

Stented Vessels: A Challenge for Histological Preparation and Microscopy

Directory of Open Access Journals (Sweden)

Andrea Nolte

2013-06-01

Full Text Available Objective: The first procedure to treat blocked coronary arteries was coronary artery bypass graft surgery. In 1977, Andreas Gruntzig introduced percutaneous transluminal coronary angioplasty (PTCA. Today, several stent systems exist ranging from bare metal stents to various drug-eluting stents. Unfortunately, our understanding of the arterial reaction to stent implantation is incomplete – primarily due to technical limitations in the histological study of stented vascular tissue. Methods: In our study, we examined different histological preparation methods based on the embedding material methacrylate. The procedure of embedding and sectioning stented porcine arteries was optimized for the specific requirements, like histochemistry, immunohistochemistry or pre-stained fluorescence. Furthermore, we used a microscopical technique described as fluorescence intensity decay shape analysis microscopy (FIDSAM to eliminate auto-fluorescence from fluorescently labeled tissue. Results: The sections were suitable for histochemical and immunohistochemical staining. Additionally, pre-labeled fluorescence in the porcine tissue was not lost by the embedding process. The evaluation of arterial cross sections with FIDSAM technology gave new, very important insights into the examination possibilities of fluorescently labeled tissue. Conclusions: Future studies of the vascular response to a variety of new stent materials will provide important clues to the pathogenesis resulting in restenosis and occlusion of stents. [J Interdiscipl Histopathol 2013; 1(3.000: 104-112

Protein losing enteropathy secondary to a pulmonary artery stent

Directory of Open Access Journals (Sweden)

Narayanswami Sreeram

2012-01-01

Full Text Available A 2-year-old patient with hypoplastic left heart syndrome presented 6 months following Fontan completion with protein-losing enteropathy (PLE. He had undergone stent implantation in the left pulmonary artery after the Norwood procedure, followed by redilation of the stent prior to Fontan completion. Combined bronchoscopic and catheterization studies during spontaneous breathing confirmed left bronchial stenosis behind the stent, and diastolic systemic ventricular pressure during expiration of 25 mm Hg. We postulate that the stent acts as a valve, against which the patient generates high expiratory pressures, which are reflected in the ventricular diastolic pressure. This may be the cause of PLE.

Insertion of a self-expandable metallic stent in canine lacrimal Sac : a long-term evaluation

Energy Technology Data Exchange (ETDEWEB)

Song, Ho Young; Sung, Kyu Bo; Yoon, Hyun Ki [Univ. of Ulsan, Ulsan (Korea, Republic of). College of Medicine; Kwon, Soon Tae [Chungnam National Univ., Taejon (Korea, Republic of). Medical School; Lee, Ho Jung; Lee, In Chul; Kim, Tae Hyung; Park, Sang Soo; Huh, Soo Jin [Univ. of Ulsan, Ulsan (Korea, Republic of). College of Medicine

1998-01-01

To evaluate the feasibility and long-term outcome of the use of self-expandable metallic Z-stents in the canine lacrimal sac. Stent placement was technically successful and well tolerated in all but one lacrimal sac, in which the stent was misplaced. At three and six months after stent placement, stent wires were not encased by epithelium, but at nine months, and one, two and three years after placement, six of the 12 stents had become encased in a proliferation of this where the stent wires contacted the lacrimal sac wall. In no lacrimal system in which stent placement had been successful was migration, stenosis or obstruction of the lacrimal system observed. One misplaced stent caused obstruction of the lacrimal sac, however . In 11 of 12 case (92%), fluoroscopic placement of an expandable metallic stent in the canine lacrimal sac was successful: in 6 of 8 cases (75%), the stent wires became encased by a proliferation of mucosa, but during long-term follow-up of 9 months to 3 years, no obstruction was observed. (author). 20 refs., 1 tab., 5 figs.

Insertion of a self-expandable metallic stent in canine lacrimal Sac : a long-term evaluation

International Nuclear Information System (INIS)

Song, Ho Young; Sung, Kyu Bo; Yoon, Hyun Ki; Kwon, Soon Tae; Lee, Ho Jung; Lee, In Chul; Kim, Tae Hyung; Park, Sang Soo; Huh, Soo Jin

1998-01-01

To evaluate the feasibility and long-term outcome of the use of self-expandable metallic Z-stents in the canine lacrimal sac. Stent placement was technically successful and well tolerated in all but one lacrimal sac, in which the stent was misplaced. At three and six months after stent placement, stent wires were not encased by epithelium, but at nine months, and one, two and three years after placement, six of the 12 stents had become encased in a proliferation of this where the stent wires contacted the lacrimal sac wall. In no lacrimal system in which stent placement had been successful was migration, stenosis or obstruction of the lacrimal system observed. One misplaced stent caused obstruction of the lacrimal sac, however . In 11 of 12 case (92%), fluoroscopic placement of an expandable metallic stent in the canine lacrimal sac was successful: in 6 of 8 cases (75%), the stent wires became encased by a proliferation of mucosa, but during long-term follow-up of 9 months to 3 years, no obstruction was observed. (author). 20 refs., 1 tab., 5 figs

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

Science.gov (United States)

Ghazi, Payam; Haji-Zeinali, Ali-Mohammad

2010-01-01

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

MRT of carotid stents: influence of stent properties and sequence parameters on visualization of the carotid artery lumen

International Nuclear Information System (INIS)

Straube, T.; Wolf, S.; Alfke, K.; Jansen, O.; Flesser, A.; Deli, M.; Nabavi, A.

2005-01-01

Purpose: To evaluate MR artifacts of carotid artery stents and to optimize stent properties and sequence parameters. Material and Methods: Four carotid artery stents - Wallstent (mediloy), Precise (nitinol), ACCULINK (nitinol) and a stent prototype (nitinol) - were investigated in a flow model of the cervical vessels. The model was made of silicon tubing and a flow pump that produces realistic flow curves of the carotid artery. To investigate the effects of magnetic susceptibility and radiofrequency induced shielding artifacts, turbo spin echo and gradient echo sequences as well as CE-MRAs were measured. To improve the visualization of the stent lumen in a CE-MRA, flip angle as well as geometry and covering of the stent prototype were altered. Results: Susceptibility artifacts in stents of the carotid artery only influence the lumen visualization at the proximal and distal end of the braided mediloy stent. A change of stent coverings has no significant influence on radiofrequency artifacts, whereas a reduction in linking elements between stent segments and a change in diameter of stent struts improves visualization of the stent lumen. By increasing the flip angle in a CE-MRA, visualization of the stent lumen is possible in both mediloy and nitinol stents. Conclusion: The choice of stent material and changes in stent geometry as well as the optimization of the flip angle of the CE-MRA may reduce susceptibility and radiofrequency artifacts, rendering feasible the CE-MRA of a stented carotid artery. (orig.)

Bioresorbable Scaffold for Treatment of Coronary Artery Lesions: Intravascular Ultrasound Results From the ABSORB Japan Trial.

Science.gov (United States)

Okada, Kozo; Honda, Yasuhiro; Kitahara, Hideki; Otagiri, Kyuhachi; Tanaka, Shigemitsu; Hollak, M Brooke; Yock, Paul G; Popma, Jeffrey J; Kusano, Hajime; Cheong, Wai-Fung; Sudhir, Krishnankutty; Fitzgerald, Peter J; Kimura, Takeshi

2018-04-09

The aim of this study was to characterize post-procedural intravascular ultrasound (IVUS) findings in the ABSORB Japan trial, specifically stratified by the size of target coronary arteries. Despite overall noninferiority confirmed in recent randomized trials comparing bioresorbable vascular scaffolds (BVS) (Absorb BVS) and cobalt-chromium everolimus-eluting metallic stents (CoCr-EES), higher event rates of Absorb BVS have been reported with suboptimal deployment, especially in small coronary arteries. In the ABSORB Japan trial, 150 patients (2:1 randomization) were scheduled in the IVUS cohort. Small vessel was defined as mean reference lumen diameter strategy, possibly different between polymeric and metallic devices, needs to be established for bioresorbable scaffold technology. (AVJ-301 Clinical Trial: A Clinical Evaluation of AVJ-301 Absorb™ BVS) in Japanese Population [ABSORB JAPAN]; NCT01844284). Copyright © 2018 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Antegrade Ureteral Stenting is a Good Alternative for the Retrograde Approach.

Science.gov (United States)

van der Meer, Rutger W; Weltings, Saskia; van Erkel, Arian R; Roshani, Hossain; Elzevier, Henk W; van Dijk, Lukas C; van Overhagen, Hans

2017-07-01

Double J (JJ) stents for treating obstructive ureteral pathology are generally inserted through a retrograde route with cystoscopic guidance. Antegrade percutaneous insertion using fluoroscopy can be performed alternatively but is less known. Indications, success rate and complications of antegrade ureteral stenting were evaluated. Data of consecutive patients in which antegrade ureteral stenting was performed were retrospectively analysed using the radiology information system and patient records. Patient characteristics, details of the antegrade JJ stent insertion procedure and registered complications were collected. Furthermore, it was investigated if prior to the antegrade procedure a retrograde attempt for JJ stent insertion was performed. Total 130 attempts for antegrade JJ stent insertion were performed in 100 patients. A percutaneous nephrostomy catheter had already been placed in the majority of kidneys (n = 109) for initial treatment of hydronephrosis. Most prevelant indication for a JJ stent was obstructive ureteral pathology due to malignancy (n = 63). A JJ stent was successfully inserted in 125 of 130 procedures. In 21 cases, previous retrograde ureteral stenting had failed but, subsequent antegrade ureteral stenting was successful. There were 8 procedure related complications; 6 infections, 1 false tract and 1 malposition. Antegrade percutaneous insertion of a JJ stent is a good alternative for retrograde insertion.

Modified nasolacrimal duct stenting

International Nuclear Information System (INIS)

Tian Min; Jin Mei; Chen Huanjun; Li Yi

2008-01-01

Objective: Traditional nasolacrimal duct stenting possesses some shortcoming including difficulty of pulling ball head guide wire from the nasal cavity with turbinate hypertrophy and nasal septal deviation. The new method of nose-oral tube track establishment can overcome the forementioned and increase the successful rate. Methods: 5 F catheter and arterial sheath were modified to be nasolacrimal duct stent delivery device respectively. Antegrade dacryocystography was taken firstly to display the obstructed site and followed by the modified protocol of inserting the guide wire through nasolacrimal duct and nasal cavity, and establishing the stent delivery track for retrograde stent placement. Results: 5 epiphora patients with failure implantation by traditional method were all succeeded through the modified stenting (100%). During 6-mouth follow-up, no serious complications and reocclusion occurred. Conclusion: The establishment of eye-nose-mouth-nose of external nasal guide wire track can improve the successful rate of nasolacrimal duct stenting. (authors)

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

Directory of Open Access Journals (Sweden)

Ying Guan

2016-08-01

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

Transient coronary aneurysm formation after Nevo™ stent implantation versus persistent coronary aneurysm after Cypher Select™ stent implantation

DEFF Research Database (Denmark)

Christiansen, Evald Høj; Lassen, Jens Flensted; Jensen, Lisette Okkels

2011-01-01

We implanted a Cypher Select™ coronary stent and two months later a Nevo™ sirolimus-eluting coronary stent in another vessel. At a prescheduled angiographic follow-up, coronary aneurysms were seen in the two stented segments, 6 and 8 months after stent implantation, respectively. Six months later......, the aneurysm had healed in the Nevo, but was still present in the Cypher stented segment. We hypothesize that aneurysm formation was induced by sirolimus and the polymer of the implanted stents, and that subsequent healing was possible in the Nevo stent after degradation of the polymer....

Forgotten Ureteral Stents: An Avoidable Morbidity

International Nuclear Information System (INIS)

Murtaza, B.; Alvi, S.

2016-01-01

Objective: To assess the clinical presentation of forgotten ureteral stents and highlight the etiological factors resulting in the retention of these stents. Study Design: Observational study. Place and Duration of Study: Department of Urology, Armed Forces Institute of Urology, Rawalpindi, from January 2010 to Jun 2011. Methodology: Thirty-eight patients, with forgotten ureteral stents, retained for more than 6 months duration, were enrolled. A detailed evaluation was performed, along with the questions regarding the patients' opinion about the ureteral stents. They were specially asked whether they knew about the stents or were they formally informed regarding the stents. Subsequently, the patients were managed according to their clinical condition. Results: The male to female ratio was 2.1:1 aged 23 - 69 years, mean being 40.24 ± 12.59 years. The time of presentation after the ureteral stenting was 7 - 180 months (mean = 28.89 ± 33.435 years). Seven patients (18.4 percentage) reported with chronic kidney disease, including ESRD in two cases. Recurrent UTI was seen in 28 cases (73.6 percentage), calculus formed over the stents in 20 cases (52.6 percentage), and stent fragmented in 5 patients (13.1 percentage). Majority of patients, (n = 23, 60.5 percentage), were not even aware of the placement of these stents while 8 (21.0 percentage) knew but were reluctant about its removal. In 3 cases (7.8 percentage), the relatives knew about the stent but never informed the patients. The stent had been removed in 2 cases (5.2 percentage), but the other broken fragment was missed. One case (2.6 percentage) each had a misconception about the permanent placement of the stents like cardiac stents and regarding degradation of the stents in situ. Conclusion: Forgotten ureteral stents produce clinical features ranging from recurrent UTI to ESRD. This preventable urological complication is primarily due to the unawareness or ignorance of the patients and their relatives

Stent underexpansion in angiographic guided percutaneous coronary intervention, despite adjunctive balloon post-dilatation, in drug eluting stent era

Directory of Open Access Journals (Sweden)

Mehrdad Taherioun

2014-01-01

Full Text Available BACKGROUND: Stent underexpansion is the most powerful predictor of long-term stent patency and clinical outcome. The purpose of this study was to evaluate the incidence and predictors of stent underexpansion despite adjunctive post-dilatation with non-compliant balloon. METHODS: After elective coronary stent implantation and adjunctive post-dilatation with non-compliant balloon and optimal angiographic result confirmed by the operator, intravascular ultrasound (IVUS was performed for all the treated lesions. If the treated lesions fulfilled the IVUS criteria, they are considered as the optimal stent group; if not, they are considered as the suboptimal group. RESULTS: From 50 patients enrolled in this study 39 (78% had optimal stent deployment and 11 (22% had suboptimal stent deployment. In the suboptimal group 7 (14% had underexpansion, 2 (4% malposition, and 2 (4% had asymmetry. There were no stent edge dissections detected by IVUS. We did not find any correlation between lesion calcification, ostial lesions, stent length, and stent underexpansion. Stent diameter ≤ 2.75 mm had a strong correlation with stent underexpansion. CONCLUSION: Despite adjunctive post-dilatation with noncompliant balloon, using a relatively small stent diameter was a strong predictor for underexpansion. IVUS guided percutaneous coronary intervention (PCI may be considered for drug eluting stent (DES implantation in relatively small vessels.   Keywords: Stent, Percutaneous Coronary Intervention, Ultrasound, Post-dilatation 

Metallic Limus-Eluting Stents Abluminally Coated with Biodegradable Polymers: Angiographic and Clinical Comparison of a Novel Ultra-Thin Sirolimus Stent Versus Biolimus Stent in the DESTINY Randomized Trial.

Science.gov (United States)

Lemos, Pedro A; Abizaid, Alexandre A C; Meireles, George C; Sarmento-Leite, Rogério; Prudente, Mauricio; Cantarelli, Marcelo; Dourado, Adriano D; Mariani, Jose; Perin, Marco A; Costantini, Costantino; Costa, Ricardo A; Costa, José Ribamar; Chamie, Daniel; Campos, Carlos A; Ribeiro, Expedito

2015-12-01

To evaluate the outcomes of patients treated with a new drug-eluting stent formulation with low doses of sirolimus, built in an ultra-thin-strut platform coated with biodegradable abluminal coating. This study is a randomized trial that tested the main hypothesis that the angiographic late lumen loss of the novel sirolimus-eluting stent is noninferior compared with commercially available biolimus-eluting stent. A final study population comprising 170 patients with one or two de novo lesions was randomized in the ratio 2:1 for sirolimus-eluting stent or biolimus-eluting stent, respectively. The primary endpoint was 9-month angiographic in-stent late lumen loss. Adverse clinical events were prospectively collected for 1 year. After 9 months, the novel sirolimus-eluting stent was shown noninferior compared with the biolimus stent for the primary endpoint (angiographic in-stent late lumen loss: 0.20 ± 0.29 mm vs. 0.15 ± 0.20 mm, respectively; P value for noninferiority <0.001). The 1-year incidence of death, myocardial infarction, repeat revascularization, and stent thrombosis remained low and not significantly different between the groups. The present randomized trial demonstrates that the tested novel sirolimus-eluting stent was angiographically noninferior in comparison with a last-generation biolimus-eluting stent. © 2015 John Wiley & Sons Ltd.

Sutureless choledochoduodenostomy with an intraluminal degradable stent in dog model

Institute of Scientific and Technical Information of China (English)

ZHU Ling-hua; LIANG Xiao; LIN Hui; WANG Yi-fan; ZHU Yi-ping; CAI Xiu-jun

2011-01-01

Background It is difficult and time-consuming for carrying out conventional hand-sewn bilioenteric anastomosis, especially for small bile duct anastomosis and laparoscopic procedure. In order to simplify it, we have developed a novel procedure of sutureless bilioenteric anastomosis with an intraluminal degradable stent. This study aimed to evaluate the feasibility and safety of this technique with cholangioduodenostomy in dog model.Methods A patent intraluminal degradable stent tube for sutureless choledochoduodenostomy in dog model was made with polylactic acid in diameter of 3 mm or 4 mm. Thirty-eight dogs were randomly divided into to a stent group (SG, n=20) and a control group (CG, n=18). Dogs in the SG underwent sutureless choledochoduodenostomy with intraluminal stent, while the CG underwent conventional choledochoduodenostomy (single layer discontinuous anastomosis with absorbable suture). Dogs of each group were divided into 4 subgroups according to time of death (1,3,6, and 12 months postoperatively) to evaluate the healing of anastomosis. Operation time, intraoperative tolerance pressure of anastomosis, rate of postoperative bile leakage, bursting pressure of anastomosis were compared between the two groups. Anastomosis tissue was observed afterwards by pathology evaluation, hydroxyproline content, serum bilirubin, liver enzyme level and magnetic resonance cholangio-pancreatography (MRCP) to assess the stricture.Results All procedures were completed successfully. The surgical time of the SG was significantly less than the CG (SG: (19.2±4.3) minutes, vs. CG: (29.2±7.1) minutes, P=0.000). One bile leakage was occurred in either group. No significant difference of intraoperative tolerance pressure of anastomosis, rate of bile leakage and postoperative bursting pressure of anastomosis, anastomotic stricture, hydroxyproline content, serum bilirubin and liver enzyme level was found between the two groups. MRCP showed no anastomosis stricture and obstruction

[The Predictive Factors of Stent Failure in the Treatment of Malignant Extrinsc Ureteral Obstruction Using Internal Ureteral Stents].

Science.gov (United States)

Matsuura, Hiroshi; Arase, Shigeki; Hori, Yasuhide; Tochigi, Hiromi

2017-12-01

In this study, we retrospectively reviewed the experiences at our single institute in the treatment of malignant extrinsic ureteral obstruction (MUO) using ureteral stents to investigate the clinical outcomes and the predictive factors of stent failure. In 52 ureters of 38 patients who had radiologically significant hydronephrosis due to MUO, internal ureteral stents (The BARD(R) INLAY(TM) ureteral stent set) were inserted. The median follow-up interval after the initial stent insertion was 124.5 days (4-1,120). Stent failure occurred in 8 ureters (15.4%) of the 7 patients. The median interval from the first stent insertion to stent failure was 88 days (1-468). A Cox regression multivariate analysis showed that the significant predictors of stent failure were bladder invasion. Based on the possibility of stent failure, the adaptation of the internal ureteral stent placement should be considered especially in a patient with MUO combined with bladder invasion.

A novel balloon assisted two-stents telescoping technique for repositioning an embolized stent in the pulmonary conduit.

Science.gov (United States)

Kobayashi, Daisuke; Gowda, Srinath T; Forbes, Thomas J

2014-08-01

A 9-year-old male, with history of pulmonary atresia and ventricular septal defect, status post complete repair with a 16 mm pulmonary homograft in the right ventricular outflow tract (RVOT) underwent 3110 Palmaz stent placement for conduit stenosis. Following deployment the stent embolized proximally into the right ventricle (RV). We undertook the choice of repositioning the embolized stent into the conduit with a transcatheter approach. Using a second venous access, the embolized stent was carefully maneuvered into the proximal part of conduit with an inflated Tyshak balloon catheter. A second Palmaz 4010 stent was deployed in the distal conduit telescoping through the embolized stent. The Tyshak balloon catheter was kept inflated in the RV to stabilize the embolized stent in the proximal conduit until it was successfully latched up against the conduit with the deployment of the overlapping second stent. One year later, he underwent Melody valve implantation in the pre-stented conduit relieving conduit insufficiency. This novel balloon assisted two-stents telescoping technique is a feasible transcatheter option to secure an embolized stent from the RV to the RVOT. © 2014 Wiley Periodicals, Inc.

Nasolacrimal Polyurethane Stent: Complications with CT Correlation

International Nuclear Information System (INIS)

Pinto, Isabel T.; Paul, Laura; Grande, Carlos

1998-01-01

Purpose: To evaluate initial results in patients with epiphora secondary to obstruction of the nasolacrimal duct treated by placement of a polyurethane stent, and to discuss the technical problems and complications arising during the procedure, with visualization of the anatomy of the drainage apparatus using computed tomography (CT). Methods: We inserted 20 polyurethane Song stents under fluoroscopic guidance after dacryocystography in 19 patients with grade 3-4 epiphora caused by idiopathic obstruction of the nasolacrimal duct. CT scans were obtained following stent placement in all patients. Results: We focus on the technical problems and complications that arose during these procedures. During negotiation of the guidewire past the obstruction at the level of the junction of the duct with the lacrimal sac, the guidewire created a false passage in a posterior suborbital direction in two cases and towards the posterior midline in another. In all cases the guidewire was withdrawn and reinserted through the proper anatomic route without further difficulty or complications. In two cases the stent was improperly positioned wholly or partially outside the nasolacrimal system (one medially, one posteriorly). In one case the stent was removed and reinserted; in the other it remains in place and functional. CT was performed in all these cases to ensure proper anatomic alignment and determine what had gone wrong. The epiphora was completely resolved in 13 cases and partially relieved in four; there were three cases of stent obstruction. Epistaxis of short duration (1 hr) occurred in seven patients and headache in one. Conclusions: Treatment of epiphora with polyurethane stents is a technique that is well tolerated by patients and achieves a high success rate, yet problems in placement may be encountered. Though no major consequences for patients are involved, cognizance of such difficulties is important to avoid incorrect positioning of stents

In vivo distribution of c-myc antisense oligodeoxynucleotides local delivered by gelatin-coated platinmn-iridium stents in rabbits and its effect on apoptosis

Institute of Scientific and Technical Information of China (English)

张新霞; 崔长琮; 许香广; 胡雪松; 方卫华; 邝碧娟

2004-01-01

Background Post-stenting restenosis is a significant clinical problem, involving vascular smooth muscle cells(VSMCs) proliferation and apoptosis. It is reported that c-myc antisense oligodeoxynucleotides (ASODNs) local delivered by catheter can inhibit VSMCs proliferation. This study was designed to assess tissue distribution of c-myc ASODN local delivered using gelatin-coated platinum-iridium (Pt-Ir) stents, and its effect on apoptosis of VSMCs. Methods Gelatin-coated Pt-Ir stents that had absorbed caroboxyfluorescein-5-succimidyl ester (FAM) labeled c-myc ASODNs (550 μg per stent) were implanted into the right carotid arteries of 6 rabbits. Tissue samples were obtained at 45 minutes, 2 hours, and 6 hours. Tissue distribution of c- myc ASODNs was assessed by fluorescence microscopy. In addition, 32 rabbits were randomly divided into two groups. Rabbits in the control group (n=16) were implanted with gelatin-coated Pt-Ir stents, and those in the treatment group (n=16) were implanted with gelatin-coated stents that had absorbed c-myc ASODNs. 7, 14, 30, or 90 days (n=4, respectively, for each group) after the stenting procedure, the stented segments were harvested, and histopathological examinations were performed to calculate neointimal area and mean neointimal thickness. The expression of c-myc was assessed using in situ hybridization (ISH) and immunohistochemical methods. Apoptotic VSMCs were detected using terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) and transmission electron microscope (TEM). Results According to fluorescence microscopic results, FAM-labeled c-myc ASODNs were concentrated in the target vessel media at the 45 minutes time point, and then dispersed to the adventitia. Morphometric analysis showed that neointimal area and mean neointimal thickness increased continuously up to 90 days after stent implantation, but that total neointimal area and mean neointimal thickness were less in the treatment group than in the

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

Science.gov (United States)

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

2016-03-01

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

Stent Design Affects Femoropopliteal Artery Deformation.

Science.gov (United States)

MacTaggart, Jason; Poulson, William; Seas, Andreas; Deegan, Paul; Lomneth, Carol; Desyatova, Anastasia; Maleckis, Kaspars; Kamenskiy, Alexey

2018-03-23

Poor durability of femoropopliteal artery (FPA) stenting is multifactorial, and severe FPA deformations occurring with limb flexion are likely involved. Different stent designs result in dissimilar stent-artery interactions, but the degree of these effects in the FPA is insufficiently understood. To determine how different stent designs affect limb flexion-induced FPA deformations. Retrievable markers were deployed into n = 28 FPAs of lightly embalmed human cadavers. Bodies were perfused and CT images were acquired with limbs in the standing, walking, sitting, and gardening postures. Image analysis allowed measurement of baseline FPA foreshortening, bending, and twisting associated with each posture. Markers were retrieved and 7 different stents were deployed across the adductor hiatus in the same limbs. Markers were then redeployed in the stented FPAs, and limbs were reimaged. Baseline and stented FPA deformations were compared to determine the influence of each stent design. Proximal to the stent, Innova, Supera, and SmartFlex exacerbated foreshortening, SmartFlex exacerbated twisting, and SmartControl restricted bending of the FPA. Within the stent, all devices except Viabahn restricted foreshortening; Supera, SmartControl, and AbsolutePro restricted twisting; SmartFlex and Innova exacerbated twisting; and Supera and Viabahn restricted bending. Distal to the stents, all devices except AbsolutePro and Innova exacerbated foreshortening, and Viabahn, Supera, Zilver, and SmartControl exacerbated twisting. All stents except Supera were pinched in flexed limb postures. Peripheral self-expanding stents significantly affect limb flexion-induced FPA deformations, but in different ways. Although certain designs seem to accommodate some deformation modes, no device was able to match all FPA deformations.

Plumbing system shock absorbers as a source of Legionella pneumophila.

Science.gov (United States)

Memish, Z A; Oxley, C; Contant, J; Garber, G E

1992-12-01

Water distribution systems have been demonstrated to be a major source of nosocomial legionellosis. We describe an outbreak in our institution in which a novel source of Legionella pneumophila was identified in the plumbing system. After an outbreak of 10 cases of legionellosis in our hospital, recommended measures including superheating of the hot water to 80 degrees C, hyperchlorination to 2 ppm, and flushing resulted in no new cases in the following 5 years. Recently, despite these control measures, three new cases occurred. Surveillance cultures of shower heads and water tanks were negative; cultures of tap water samples remained positive. This prompted a search for another reservoir. Shock absorbers installed within water pipes to decrease noise were suspected. One hundred twenty-five shock absorbers were removed and cultured. A total of 13 (10%) yielded heavy growth of L. pneumophila (serogroup 1). Since their removal, no new cases have been found and the percentage of positive results of random tap water culture has dropped from 20% to 5%. This is the first report that identifies shock absorbers as a possible reservoir for L. pneumophila. We recommend that institutions with endemic legionellosis assess the water system for possible removal of shock absorbers.

Advantages of novel BioMimeTM Sirolimus Eluting Coronary Stent system. Moving towards biomimicry.

Science.gov (United States)

Upendra, K; Sanjeev, B

2012-02-01

Since the first reported use of percutaneous transluminal coronary angioplasty (PTCA), advancements in interventional cardiology arena have been fast paced. Within the last ten years, these developments have been exponential. Developers & clinicians are fast adapting from the learning curve awarded by the time course of DES evolution. In that light BioMimeTM Sirolimus Eluting Coronary Stent comes as a fresh thought in taking stents towards a biomimicry concept. The stent is built on an ultra-low strut thickness (65 µm) cobalt chromium stent platform, using an intelligent hybrid of close and open cells allowing for morphology mediated expansion, employs a well known anti-proliferative - Sirolimus that elutes from a biodegradable co-polymer formulation in 30 days and ensures high coating integrity and low coating thickness of 2 µm. The resultant stent demonstrates almost 100% endothelialization at 30 days in preclinical model and zero percent MACE >18 months in the primary efficacy and safety clinical study.

Heterogeneous Intravascular Ultrasound Findings of Stent Thrombosis

OpenAIRE

Morofuji, Toru; Inaba, Shinji; Aisu, Hiroe; Takahashi, Kayo; Saito, Makoto; Higashi, Haruhiko; Yoshii, Toyofumi; Sumimoto, Takumi

2017-01-01

Objective The underlying mechanisms of stent thrombosis are not completely understood. Methods We experienced 12 definite stent thrombosis cases (1 early, 1 late, and 10 very late) at our hospital from July 2011 to April 2016 and evaluated the possible causes of stent thrombosis by intravascular ultrasound (IVUS). Results Five different potential morphological causes of stent thrombosis (neoatherosclerosis, stent malapposition, stent fracture, edge dissection, and stent underexpansion) were d...

Coronary In-Stent Restenosis: Assessment with Corrected Coronary Opacification Difference across Coronary Stents Measured with CT Angiography.

Science.gov (United States)

Gao, Yang; Lu, Bin; Hou, Zhi Hui; Yu, Fang Fang; Yin, Wei Hua; Wang, Zhi Qiang; Wu, Yong Jian; Mu, Chao Wei; Meinel, Felix G; McQuiston, Andrew D; Schoepf, U Joseph

2015-05-01

To determine whether changes in coronary opacification normalized to the aorta (corrected coronary opacification [CCO]) across stents can help identify in-stent restenosis (ISR) severity with use of invasive coronary angiography as the standard of reference. This study was approved by the institutional review board, and the requirement to obtain informed consent was waived. The authors retrospectively analyzed 106 patients (88 men, 18 women; mean age, 59.6 years ± 10.4; age range, 36-84 years) who had previously undergone stent implantation within 3 months of coronary computed tomographic (CT) angiography. Attenuation values in the coronary lumen were measured proximal and distal to the stents and normalized to the descending aorta. The CCO difference across the stent was compared with the severity of ISR. One-way analysis of variance least significant difference was used for comparison. A total of 141 stents were assessed. Seventy-six stents were normally patent, 18 had ISR of less than 50%, 28 had ISR of 50%-99%, and 19 were fully occluded. The median CCO differences in the four groups were 0.078, 0.163, 0.346, and 0.606, respectively. There was no significant difference between stents with an ISR of at least 50% and those with total occlusion (P = .056), although the other groups had significant differences at pairwise comparison (P stents smaller than 3 mm in diameter, the median CCO differences in the four groups were 0.086, 0.136, 0.390, and 0.471, respectively. The CCO differences across normal stents and stents with ISR of less than 50% were significantly less than those across stents with an ISR of at least 50% and those with total occlusion (P stents with no ISR and those with an ISR of less than 50% (P = .821) and between stents with an ISR of at least 50% and those with an ISR of 100% (P = .836). The CCO difference across coronary stents is related to ISR severity in obstructive ISR in stents smaller than 3 mm in diameter. © RSNA, 2014.

The INNOVATION Trial: four-year safety and effectiveness of the INCRAFT® AAA Stent-Graft System for endovascular repair.

Science.gov (United States)

Pratesi, Giovanni; Pratesi, Carlo; Chiesa, Roberto; Coppi, Gioacchino; Scheinert, Dierk; Brunkwall, Jan S; van der Meulen, Stefaan; Torsello, Giovanni

2017-10-01

This paper reports the 4-year safety and effectiveness of the INCRAFT® AAA Stent-Graft System (Cordis Corp., Milpitas, CA, USA), an ultra-low-profile device for the treatment of abdominal aortic aneurysms. The INNOVATION Trial is the prospective, first-in-human, multicenter trial to evaluate the safety and effectiveness of the INCRAFT® System. Patients underwent annual clinical and computed tomography angiography examination as part of the study protocol. The INCRAFT® AAA Stent-Graft System is a customizable tri-modular design, with an ultra-low profile (14-Fr) delivery system. Patient were treated under approved protocol, the prescribed clinical and imaging follow-up at annually through 5 years. Results analyzed and adjudicated by a clinical events committee, independent core laboratory, and a data safety and monitoring board. This manuscript reports results through 4 years of follow-up. A total of 60 patients were enrolled in the trial, all of whom were successfully treated. Follow-up rates at 1 and 4 years were 93% (56/60) and 85% (51/60), respectively. All-cause mortality at 4 years was 17.6% and no death was AAA-, device-, or procedure-related. The secondary reintervention rate at 1 year was 4.6%, primarily the result of stent thrombosis. In total, 10 patients required 13 post-procedure interventions within 4-years of follow-up (2 to repair a type I endoleak, 4 to repair a type II endoleak, 1 for stent thrombosis, 1 for renal stenosis, 1 for aneurysm enlargement, 2 for limb migration and 2 for prosthesis stenosis or occlusion). There were 4 cases (10%) of aneurysm enlargement reported at the 4 year follow-up. At 4 years, 38 out of 39 patients were free from type I and III endoleaks. There were no proximal type I or type III endoleaks at 4-year follow-up. Core laboratory evaluation of the postoperative imaging studies indicated absence of endograft migration while a single fracture was demonstrated without any clinical sequelae. The INCRAFT® AAA Stent

PulmoStent : In Vitro to In Vivo Evaluation of a Tissue Engineered Endobronchial Stent

NARCIS (Netherlands)

Thiebes, Anja Lena; Kelly, Nicola; Sweeney, Caoimhe A.; McGrath, Donnacha J.; Clauser, Johanna; Kurtenbach, Kathrin; Gesche, Valentine N.; Chen, Weiluan; Kok, Robbert Jan; Steinseifer, Ulrich; Bruzzi, Mark; O’Brien, Barry J.; McHugh, Peter E.; Jockenhoevel, Stefan; Cornelissen, Christian G.

Currently, there is no optimal treatment available for end stage tumour patients with airway stenosis. The PulmoStent concept aims on overcoming current hurdles in airway stenting by combining a nitinol stent with a nutrient-permeable membrane, which prevents tumour ingrowth. Respiratory epithelial

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

International Nuclear Information System (INIS)

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

2006-01-01

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

Stent migration after right ventricular outflow tract stenting in the severe cyanotic Tetralogy of Fallot case

Directory of Open Access Journals (Sweden)

Tamaki Hayashi

2017-01-01

Full Text Available We report our experience with a stent migration after right ventricle outflow tract stenting and converted to patent ductus arteriosus stenting in Tetralogy of Fallot (TOF with severe infundibular stenosis. Finally, the patient achieved to TOF repair, and the migrated stent was removed without any complication.

Creation of individual ideally shaped stents using multi-slice CT: in vitro results from the semi-automatic virtual stent (SAVS) designer

International Nuclear Information System (INIS)

Hyodoh, Hideki; Katagiri, Yoshimi; Hyodoh, Kazusa; Akiba, Hidenari; Hareyama, Masato; Sakai, Toyohiko

2005-01-01

To plan stent-grafting for thoracic aortic aneurysm with complicated morphology, we created a virtual stent-grafting program [Semi Automatic Virtual Stent (SAVS) designer] using three-dimensional CT data. The usefulness of the SAVS designer was evaluated by measurement of transformed anatomical and straight stents. Curved model images (source, multi-planer reconstruction and volume rendering) were created, and a hollow virtual stent was produced by the SAVS designer. A straight Nitinol stent was transformed to match the curved configuration of the virtual stent. The accuracy of the anatomical stent was evaluated by experimental strain phantom studies in comparison with the straight stent. Mean separation length was 0 mm in the anatomical stent [22 mm outer diameter (OD)] and 5 mm in the straight stent (22 mm OD). The straight stent strain voltage was four times that of the anatomical stent at the stent end. The anatomical stent is useful because it fits the curved structure of the aorta and reduces the strain force compared to the straight stent. The SAVS designer can help to design and produce the anatomical stent. (orig.)

Study of the clinical effect of SIS magnesium alloy absorbable biliary stent in treatment of patients with malignant obstructive jaundice%SIS镁合金可吸收胆管支架治疗恶性梗阻性黄疸疗效分析

Institute of Scientific and Technical Information of China (English)

宋勇; 秦高平; 杜立学; 胡海田; 张昊宇

2017-01-01

Objective To investigate the clinical effect of SIS magnesium alloy absorbable biliary stent in the treatment of patients with malignant obstructive jaundice.Methods 67 patients with malignant obstructive jaundice treated with EBMSD in our hospital were selected and divided into control group and observation group according to the different metal biliary stent.The patients in control group accepted normal Nickel titanium alloy stent while the patients in observation group accepted magnesium alloy absorbable biliary stent.The TBIL,ALT,ALP,AST,DBIL,IBIL of all the patients were detected before and after one week of the operation.The complication after operation,survival rate and drainage unobstructed rate after 6 months were observed.Results The stents placing successful rate of control group was 917％ and 93.5％ for observation group (P＞0.05).After operation,TBIL,ALT,ALP,AST,DBIL,IBIL of the two groups were better than those before operation and there was no significant difference between the two groups (P＞0.05).On the other hand,more complications was observed in the control groups (P＜0.05).After 6 months,the survival rate of observation group was 82.3 ％ and drainage unobstructed rate was 72.4,which were better than those in control group (P＜0.05).Conclusion SIS magnesium alloy absorbable biliary stent could improve the liver function and reduce the malignant obstructive jaundice symptoms and longer the life of the patients with malignant obstructive jaundice.%目的 分析SIS镁合金可吸收胆管支架治疗恶性梗阻性黄疸的临床疗效.方法 选取67例接受胆道金属支架引流术(EBMSD)的恶性梗阻性黄疸患者,按照置入不同金属支架分为对照组和实验组,对照组患者置入普通镍钛合金支架,实验组患者置入SIS镁合金可吸收支架.检测两组患者术前1周及术后1�

Configuration affects parallel stent grafting results.

Science.gov (United States)

Tanious, Adam; Wooster, Mathew; Armstrong, Paul A; Zwiebel, Bruce; Grundy, Shane; Back, Martin R; Shames, Murray L

2018-05-01

A number of adjunctive "off-the-shelf" procedures have been described to treat complex aortic diseases. Our goal was to evaluate parallel stent graft configurations and to determine an optimal formula for these procedures. This is a retrospective review of all patients at a single medical center treated with parallel stent grafts from January 2010 to September 2015. Outcomes were evaluated on the basis of parallel graft orientation, type, and main body device. Primary end points included parallel stent graft compromise and overall endovascular aneurysm repair (EVAR) compromise. There were 78 patients treated with a total of 144 parallel stents for a variety of pathologic processes. There was a significant correlation between main body oversizing and snorkel compromise (P = .0195) and overall procedural complication (P = .0019) but not with endoleak rates. Patients were organized into the following oversizing groups for further analysis: 0% to 10%, 10% to 20%, and >20%. Those oversized into the 0% to 10% group had the highest rate of overall EVAR complication (73%; P = .0003). There were no significant correlations between any one particular configuration and overall procedural complication. There was also no significant correlation between total number of parallel stents employed and overall complication. Composite EVAR configuration had no significant correlation with individual snorkel compromise, endoleak, or overall EVAR or procedural complication. The configuration most prone to individual snorkel compromise and overall EVAR complication was a four-stent configuration with two stents in an antegrade position and two stents in a retrograde position (60% complication rate). The configuration most prone to endoleak was one or two stents in retrograde position (33% endoleak rate), followed by three stents in an all-antegrade position (25%). There was a significant correlation between individual stent configuration and stent compromise (P = .0385), with 31

Advances in Clinical Research of Biodegradable Stents%医用可降解血管支架临床研究进展

Institute of Scientific and Technical Information of China (English)

张小农; 左敏超; 张绍翔; 吴宏流; 王文辉; 陈文智; 倪嘉桦

2017-01-01

心血管疾病是危害国人身体健康的第一大疾病,介入治疗已成为患者的重要选择,植入血管支架被认为是目前最便捷有效的技术.本文在简单介绍经皮冠脉介入治疗的发展历程的基础上,综合比较了美国雅培公司研发的生物可吸收高分子支架以及德国百多力公司研发的生物可降解镁合金支架的一系列随机临床实验数据,总结了可降解吸收支架目前存在的缺陷并分析了其未来的发展趋势.%Cardiovascular disease has become the first major disease that is harmful to people's health,vascular stents and other percutaneous coronary interventions are considered the most important and effective treatment technology of cardiovascular disease.In this review,the development about percutaneous coronary interventions was simply introduced,through comparing a series of randomized clinical trial data of bioabsorbable vascular stents developed by Abbott of the United States and absorbable magnesium stents developed by Biotronik of Germany,summarizing the shortcomings and analyzing trend in the future of absorbable stents.

Direct implantation of rapamycin-eluting stents with bioresorbable drug carrier technology utilising the Svelte coronary stent-on-a-wire: the DIRECT II study.

Science.gov (United States)

Verheye, Stefan; Khattab, Ahmed A; Carrie, Didier; Stella, Pieter; Slagboom, Ton; Bartunek, Jozef; Onuma, Yoshinobu; Serruys, Patrick W

2016-08-05

Our aim was to demonstrate the safety and efficacy of the Svelte sirolimus-eluting coronary stent-on-a-wire Integrated Delivery System (IDS) with bioresorbable drug coating compared to the Resolute Integrity zotarolimus-eluting stent with durable polymer in patients with de novo coronary artery lesions. Direct stenting, particularly in conjunction with transradial intervention (TRI), has been associated with reduced bleeding complications, procedure time, radiation exposure and contrast administration compared to conventional stenting with wiring and predilatation. The low-profile Svelte IDS is designed to facilitate TRI and direct stenting, reducing the number of procedural steps, time and cost associated with coronary stenting. DIRECT II was a prospective, multicentre trial which enrolled 159 patients to establish non-inferiority of the Svelte IDS versus Resolute Integrity using a 2:1 randomisation. The primary endpoint was angiographic in-stent late lumen loss (LLL) at six months. Target vessel failure (TVF), as well as secondary clinical endpoints, will be assessed annually up to five years. At six months, in-stent LLL was 0.09±0.31 mm in the Svelte IDS group compared to 0.13±0.27 mm in the Resolute Integrity group (p<0.001 for non-inferiority). TVF at one year was similar across the Svelte IDS and Resolute Integrity groups (6.5% vs. 9.8%, respectively). DIRECT II demonstrated the non-inferiority of the Svelte IDS to Resolute Integrity with respect to in-stent LLL at six months. Clinical outcomes at one year were comparable between the two groups.

Reintervention for stent occlusion after bilateral self-expandable metallic stent placement for malignant hilar biliary obstruction.

Science.gov (United States)

Inoue, Tadahisa; Naitoh, Itaru; Okumura, Fumihiro; Ozeki, Takanori; Anbe, Kaiki; Iwasaki, Hiroyasu; Nishie, Hirotada; Mizushima, Takashi; Sano, Hitoshi; Nakazawa, Takahiro; Yoneda, Masashi; Joh, Takashi

2016-11-01

Endoscopic reintervention for stent occlusions following bilateral self-expandable metallic stent (SEMS) placement for malignant hilar biliary obstruction (MHBO) is challenging, and time to recurrent biliary obstruction (RBO) of the revisionary stent remains unclear. We aimed to clarify a suitable reintervention method for stent occlusions following bilateral SEMS placement for MHBO. Between 2002 and 2014, 52 consecutive patients with MHBO who underwent endoscopic reintervention for stent occlusion after bilateral SEMS placement were enrolled at two university hospitals and one tertiary care referral center. We retrospectively evaluated the technical and functional success rates of the reinterventions, and the time to RBO of the revisionary stents. Technical and functional success rates of the reinterventions were 92% (48/52) and 90% (43/48), respectively. Univariate analysis did not determine any significant predictive factors for technical and functional failures. Median time to RBO of the revisionary stents was 68 days. Median time to RBO was significantly longer for revisionary SEMS placement than for plastic stent placement (131 days vs 47 days, respectively; log-rank test, P = 0.005). Revisionary SEMS placement was the only independent factor that was significantly associated with a longer time to RBO of the revisionary stent in the multivariate Cox proportional hazards analysis (hazard ratio 0.37; 95% confidence interval 0.14-0.95; P = 0.039). Revisionary SEMS placement is a suitable endoscopic reintervention method for stent occlusion following bilateral SEMS placement from the perspective of time to RBO of the revisionary stent. © 2016 Japan Gastroenterological Endoscopy Society.

A comparison of clinical efficacy between covered stent-grafts and bare stents in transjuglar in-trahepatic portosystemic shunt

International Nuclear Information System (INIS)

Jiang Yongbin; Zhang Xitong; Zhang Wei; Xia Yonghui; Liang Songnian; Xu Ke

2010-01-01

Objective: To compare the clinical efficacy between covered stent and uncovered stent in transjuglar in-trahepatic portosystemic shunt (TIPS). Methods: Thirty patients with liver cirrhosis (portal hypertension), who received TIPS, were retrospectively studied. All patients were divided into two groups covered-stent group (n=20) and uncovered-stent group (n=10). For each patient, portal pressure was measured before and after operation, and the patency of shunt was evaluated by color Doppler ultrasound after operation. The mortality, recurrent bleeding rate and incidence of hepatic encephalopathy were analyzed by Fisher exact probability test. Results: The TIPS treatment was successful in all patients, the portal pressure in the covered-stent group reduced from (3.78 ± 0.50)kPa to (2.13 ± 0.44) kPa and that of the uncovered-stent group reduced from (3.67 ± 0.48)kPA TO (2.13 ± 0.35)kPa. Twenty-six cases were postoperatively followed-up (17 cases in covered-stent group, 9 cases in uncovered-stent group). the follow-up period varied from 7 days to 62 months (median follow-up period was 23 months). Thirteen patients died of upper gastrointestinal bleeding and hepatic failure. The difference of mortality between covered-stent group (8/17) and uncovered-stent group (5/17) and the uncovered-stent group (3/9) was not different too (P>0.05). The incidence of hepatic encephalopathy in the covered-stent group (4/17) was not different from that of the uncovered-stent group (2/9) (P>0.05). The patency rates of 6 months and 12 months reached 100% in the covered-stent group, which were higher than those in the uncovered-stent group 77.8% (7/9) and 55.6%(5/9) (P<0.05). Conclusions: The patency rate of shunt at 12 months after TIPS was higher in the covered-stent group than the uncovered-stent group, while the mortality, recurrent bleeding rate and incidence of hepatic encephalopathy were not significantly different between the two groups. (authors)

Comparison of closed-cell and hybrid-cell stent designs in carotid artery stenting: clinical and procedural outcomes

Directory of Open Access Journals (Sweden)

Ersan TatlI

2017-05-01

Full Text Available Introduction: Carotid artery stenting (CAS is a promising alternative to surgery in high-risk patients. However, the impact of stent cell design on outcomes in CAS is a matter of continued debate. Aim : To compare the periprocedural and clinical outcomes of different stent designs for CAS with distal protection devices. Material and methods : All CAS procedures with both closed- and hybrid-cell stents performed at our institution between February 2010 and December 2015 were analyzed retrospectively. Adverse events were defined as death, major stroke, minor stroke, transient ischemic attack and myocardial infarction. Periprocedural and 30-day adverse events and internal carotid artery (ICA vasospasm rates were compared between the closed-cell and hybrid-cell stent groups. Results : The study included 234 patients comprising 146 patients with a closed-cell stent (Xact stent, Abbott Vascular (mean age: 68.5 ±8.6; 67.1% male and 88 patients with a hybrid-cell stent (Cristallo Ideale, Medtronic (mean age: 67.2 ±12.8; 68.2% male. There was no significant difference between the groups with respect to periprocedural or 30-day adverse event rates. While there was no difference in terms of tortuosity index between the groups, there was a higher procedural ICA vasospasm rate in the closed-cell stent group (35 patients, 23% compared with the hybrid-cell stent group (10 patients, 11% (p = 0.017. Conclusions : The results of this study showed no significant difference in the clinical adverse event rates after CAS between the closed-cell stent group and the hybrid-cell stent group. However, procedural ICA vasospasm was more common in the closed-cell stent group.

Comparison of Acute Thrombogenicity for Magnesium versus Stainless Steel Stents in a Porcine Arteriovenous Shunt Model.

Science.gov (United States)

Lipinski, Michael J; Acampado, Eduardo; Cheng, Qi; Adams, Lila; Torii, Sho; Gai, Jiaxiang; Torguson, Rebecca; Hellinga, David G; Joner, Michael; Harder, Claus; Zumstein, Philine; Finn, Aloke V; Kolodgie, Frank D; Virmani, Renu; Waksman, Ron

2018-05-08

Aims The aetiology for reduced thrombogenicity of the Magmaris resorbable magnesium scaffold (RMS) when compared with the Absorb bioresorbable vascular scaffold remains unclear. We therefore investigated whether the Magmaris RMS has platelet-repelling properties by comparing its acute thrombogenicity with an equivalent stainless steel stent in an arteriovenous shunt model. Methods and Results An ex vivo porcine carotid jugular arteriovenous shunt was established and connected to Sylgard tubing containing the Magmaris RMS with sirolimus-eluting PLLA coating and an equivalent 316L stainless steel stent with sirolimus-eluting PLLA coating. Six shunts (2 shunt runs per pig) were run comparing the 2 scaffolds (n=9) in alternating order. Nested generalised linear mixed models were employed to compare variables between scaffold groups. Confocal fluorescent microscopy costaining CD61/CD42b demonstrated that the 316L equivalent stent had significantly greater platelet coverage of the total scaffold compared with Magmaris (5.8% vs. 2.8%, Rate ratio 2.21 [1.41, 3.47], p=0.012). Scanning electron microscopy demonstrated significantly greater thrombus deposition on the 316L equivalent stent as a percentage of the total scaffold compared with Magmaris (8.0% vs. 5.3%, p=0.009). Magmaris also had significantly less CD14 positive monocyte deposition and a trend toward less PM-1 positive neutrophil compared with the 316L equivalent stent. Conclusion Despite having identical scaffold characteristics regarding geometrical design, Magmaris had significantly less thrombogenicity and inflammatory cell deposition compared with the equivalent 316L stainless steel stent in a porcine arteriovenous shunt model. These data suggest resorbable magnesium scaffolds may have inherent properties that reduce adhesion of platelets and inflammatory cells.

Current status of infrapopliteal artery stenting in patients with critical limb ischemia Estado atual do uso de stents na artéria infrapolítea em pacientes com isquemia crítica do membro

Directory of Open Access Journals (Sweden)

Marc Bosiers

2008-09-01

Full Text Available Due to the fear that early thrombosis and late luminal loss resulting from intimal hyperplasia might impede sustained patency of small-caliber arteries, such as those of the infrapopliteal bed, stent implantation in below-knee vessels remains controversial and is generally reserved for cases with a suboptimal outcome after percutaneous transluminal angioplasty (i.e. > 50% residual stenosis, flow-limiting dissection. Although evidence starts to build, favoring the use of stenting in the tibial area, results of well-conducted randomized controlled trials have to be awaited to change this strategy. Because of diameter similarities with coronary arteries, the first stents applied in the infrapopliteal vessels were all coronary devices. Once the feasibility of the stenting approach with these coronary products was shown, device manufacturers started to develop a dedicated infrapopliteal product range. To date, a broad spectrum of stent types has been used and investigated for the given indication. This article overviews the available literature and results of different balloon-expandable (bare metal, passive coated, drug eluting, self-expanding and absorbable stent types available for below-the-knee application and gives recommendations for future device technology advancements.Devido ao receio de que a trombose precoce ou a estenose tardia por hiperplasia intimal possam impedir a manutenção da perviedade em vasos de pequeno calibre, o uso de stents pós-angioplastia no leito arterial infrapoplíteo permanece controverso e geralmente é reservado aos casos de resultado subótimo após angioplastia transluminal percutânea (isto é, estenose residual > 50% ou dissecção com limitação do fluxo. Apesar de evidências começarem a favorecer o uso de stents no segmento tibial, é necessário aguardar o resultado de ensaios controlados, randomizados e bem conduzidos para mudar esta estratégia. Sendo estes vasos infrapoplíteos de diâmetro similar �

Metallic stents provide better QOL than plastic stents in patients with stricture of unresectable advanced esophageal cancer

International Nuclear Information System (INIS)

Ohta, Kazuki; Nagahara, Akihito; Iijima, Katsuyori

2006-01-01

The aim of this study was to elucidate the utility and safety of treatment with esophageal stents (plastic and metallic stents) for unresectable advanced esophageal cancer. Between 1992 and 2002, 14 cases of unresectable advanced esophageal cancer were treated with esophageal stents (the plastic stent group, 7 cases; and the metallic stent group, 7 cases). Of these, 10 cases had a history of chemotherapy and or radiotherapy. An improvement in oral intake and performance status (PS), survival time, periods at home, and adverse events were compared between the two groups. After stenting, oral intake and PS were significantly improved in the metallic stent group. Follow-up at home was possible in 71.4%. There was no significant difference in survival or duration of time at home between the two groups. All adverse events were controllable and there was no difference between the two groups. Stenting not only improved oral intake and PS but also allowed a stay at home, resulting in a marked improvement in patients' quality of life (QOL). Stenting was performed safely even in cases with a history of radiotherapy. There was no difference in survival, ratios of staying at home, and safety between the two groups, but QOL was significantly improved in the metallic stent group. These outcomes indicate that placement of metallic stents should be actively considered to treat stricture due to advanced esophageal cancer. (author)

Clinical experience in coronary stenting with the Vivant Z Stent.

Science.gov (United States)

Chee, K H; Siaw, F S; Chan, C G; Chong, W P; Imran, Z A; Haizal, H K; Azman, W; Tan, K H

2005-06-01

This single centre study was designed to demonstrate feasibility, safety and efficacy of the Vivant Z stent (PFM AG, Cologne, Germany). Patients with de novo lesion were recruited. Coronary angioplasty was performed with either direct stenting or after balloon predilatation. Repeated angiogram was performed 6 months later or earlier if clinically indicated. Between January to June 2003, a total of 50 patients were recruited (mean age 55.8 +/- 9 years). A total of 52 lesions were stented successfully. Mean reference diameter was 2.77 mm (+/-0.59 SD, range 2.05-4.39 mm) with mean target lesion stenosis of 65.5% (+/-11.6 SD, range 50.1-93.3%). Forty-six lesions (88.5%) were American College of Cardiologist/American Heart Association class B/C types. Direct stenting was performed in 18 (34.6%) lesions. Mean stent diameter was 3.18 mm (+/-0.41 SD, range 2.5-4 mm), and mean stent length was 14.86 mm (+/-2.72 SD, range 9-18 mm). The procedure was complicated in only one case which involved the loss of side branch with no clinical sequelae. All treated lesions achieved Thrombolysis In Myocardial Infarction 3 flow. Mean residual diameter stenosis was 12.2% (+/-7.55 SD, range 0-22.6%) with acute gain of 1.72 mm (+/-0.50 SD, range 0.5-2.8). At 6 months, there was no major adverse cardiovascular event. Repeated angiography after 6 months showed a restenosis rate of 17% (defined as >50% diameter restenosis). Mean late loss was 0.96 mm (+/-0.48 SD) with loss index of 0.61 (+/-0.38 SD). The restenosis rate of those lesions less than 3.0 mm in diameter was 22.2% compared with 6.25% in those lesions more than 3.0 mm in diameter. The Vivant Z stent was shown to be safe and efficacious with low restenosis rate in de novo coronary artery lesion.

Comparison of Recanalization and In-Stent Stenosis Between the Low-Profile Visualized Intraluminal Support Stent and Enterprise Stent-Assisted Coiling for 254 Intracranial Aneurysms.

Science.gov (United States)

Feng, Xin; Qian, Zenghui; Liu, Peng; Zhang, Baorui; Wang, Luyao; Guo, Erkang; Wen, Xiaolong; Xu, Wenjuan; Jiang, Chuhan; Wu, Zhongxue; Li, Youxiang; Liu, Aihua

2018-01-01

To compare the rates of recanalization and in-stent stenosis between the Enterprise (EP) and low-profile visualized intraluminal support (LVIS) stent deployments for intracranial aneurysms (IAs), and the factors associated therein. Between June 2014 and July 2016, 142 patients with a total of 161 IAs were treated by LVIS stent-assisted coiling and 111 patients with a total of 142 IAs were treated by EP stent-assisted coiling at our institution. Procedure-related complications, angiographic follow-up results, and clinical outcomes were analyzed statistically. The rates of initially complete and near-complete IA occlusion immediately after the procedure were similar in the LVIS and EP groups (94.3% vs. 89.9%; P = 0.275). On follow-up, complete and near-complete occlusion rates and recanalization rates were also similar in the 2 groups (96.6% vs. 92.1%; P =0.330 and 8.0% vs. 13.5%; P = 0.245, respectively). On logistic regression analysis, a higher size ratio (SR) was significantly associated with the recanalization of aneurysms in the EP group, but not in the LVIS group. The rate of moderate to severe in-stent stenosis was lower in the LVIS group (10.2%) than in the EP group (16.8%), but the difference was not statistically significant (P = 0.198). Our data show acceptable rates of complete and near-complete occlusion with both the LVIS and EP stents. LVIS stents were associated with lower rates of recanalization and in-stent stenosis, but the difference was not significant. Higher SR (≥2) was a significant predictor of recanalization in IAs treated with EP stents, but not in those treated with LVIS stents. Copyright © 2017. Published by Elsevier Inc.

Influence of a pressure gradient distal to implanted bare-metal stent on in-stent restenosis after percutaneous coronary intervention

DEFF Research Database (Denmark)

Jensen, Lisette Okkels; Thayssen, Per; Thuesen, Leif

2007-01-01

pullback recording in the entire length of the artery. METHODS AND RESULTS: In 98 patients with angina pectoris, 1 de novo coronary lesion was treated with a bare-metal stent. After stent implantation, pressure wire measurements (P(d)=mean hyperemic coronary pressure and P(a)=mean aortic pressure) were......-stent restenosis after 9 months. CONCLUSIONS: A residual abnormal P(d)/P(a) distal to a bare-metal stent was an independent predictor of in-stent restenosis after implantation of a coronary bare-metal stent. Udgivelsesdato: 2007-Dec-11......BACKGROUND: Fractional flow reserve predicts cardiac events after coronary stent implantation. The aim of the present study was to assess the 9-month angiographic in-stent restenosis rate in the setting of optimal stenting and a persisting gradient distal to the stent as assessed by a pressure wire...

Study on the application of big cup membranate stent on restenosis after stenting for carcinoma of esophago cardia

International Nuclear Information System (INIS)

Wang Xiuping; Yao Zhongqiang; Liu Jian; Zhang Yan

2007-01-01

Objective: To evaluate the clinical value of self-designed big cup membranate stent on restenosis after stenting for carcinoma of esophago-cardia. Methods: 12 cases of restenosis after stenting for carcinoma of esophago-cardia were involved in the study. Self-designed big cup membranate stent made by Nanjing Weichuang Company (the length of the cup was 3.5 cm)was placed into the constricted stent under guidance of fluoroscopy. Clinical effect, restenosis, and complications were observed during followed up. Results: All the 12 cases of big cup membranat stent placement went along smoothly without indigitation of the cup of the stent. Follow-up of 1.5-8 months showed that 2 cases developed severe restenosis on the big cup of the stem, resulting in third grade difficult deglutition. Among them, one occurred 1 month after stenting, caused by hyperplasia of large amount of granulation tissue; another occurred 6 months after stenting, caused by growth of tumor tissue. 3 cases developed mild to moderate restenosis, 2.3-7 months (mean: 4.6 months) after stenting, with result of first grade difficult deglutition. The remaining 7 cases (mean 5.6 months follow-up) did not have difficulty during deglutition. Conclusions: Application of big cup membranate stent on restenosis after stenting for carcinoma of esophago-cardia can effectively prevent the stent from moving downwards and thus lower down the rate of restenosis, and postpone the occurrence of restenosis. (authors)

Experimental study of the preventive effect of 1'03Pd stent on in-stent restenosis in rabbit iliac artery

International Nuclear Information System (INIS)

Luo Quanyong; Chen Libo; Yuan Zhibin; Lu Hankui; Zhu Ruisen

2003-01-01

Objective: To investigate the ability of γ-emitting 103 Pd radioactive stent implantation for preventing in-stent restenosis in iliac artery of rabbits. Methods: Twenty New Zealand white rabbits were divided into six groups on the basis of radioactivity loading [2.22 (n=3), 5.55 (n=4), 9.25 (n=4), 14.8 (n=3), 22.2 (n=3), 33.3 MBq (n=3)]. 103 Pd stent was implanted in one of the two iliac arteries of each rabbit and nonradioactive stent in the contralateral artery. The rabbits were fed with high fat diet. Treatment efficiency was assessed by angiography and quantitative histomorphometry of the stented iliac segments 28 d after the implantation. Results: Quantitative histomorphometry analysis indicated that 103 Pd stents induced a significant reduction in neointimal area and the percentage of stenosis within radioactive stents was lower compared with that in the control stents. Nevertheless, the suppression of neointima formation by 103 Pd stent implantation was not in a dose-dependent manner. Conclusions: Low-dose intravascular brachytherapy via a γ-particle-emitting 103 Pd radioactive stent potently inhibits neointimal hyperplasia and prevents the in-stent restenosis in rabbit iliac artery. 103 Pd stent implantation probably can be employed as a novel means to prevent in-stent restenosis

Stent Thrombosis is the Primary Cause of ST-Segment Elevation Myocardial Infarction following Coronary Stent Implantation

DEFF Research Database (Denmark)

Kristensen, Søren Lund; Galløe, Anders M; Thuesen, Leif

2014-01-01

Background: The widespread use of coronary stents has exposed a growing population to the risk of stent thrombosis, but the importance in terms of risk of ST-segment elevation myocardial infarctions (STEMIs) remains unclear. Methods: We studied five years follow-up data for 2,098 all-comer patients...... treated with coronary stents in the randomized SORT OUT II trial (mean age 63.6 yrs. 74.8% men). Patients who following stent implantation were readmitted with STEMI were included and each patient was categorized ranging from definite-to ruled-out stent thrombosis according to the Academic Research...... Consortium definitions. Multivariate logistic regression was performed on selected covariates to assess odds ratios (ORs) for definite stent thrombosis. Results: 85 patients (4.1%), mean age 62.7 years, 77.1% men, were admitted with a total of 96 STEMIs, of whom 60 (62.5%) had definite stent thrombosis...

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

Science.gov (United States)

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 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.

Biomechanical analysis on stent materials used as cardiovascular implants

Science.gov (United States)

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

2018-04-01

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

Evaluation of a novel stent technology: the Genous EPC capturing stent

NARCIS (Netherlands)

Klomp, M.

2012-01-01

Tegenwoordig gebruiken ziekenhuizen een nieuwe stent bij dotterbehandelingen van kransslagadervernauwingen. Deze Genous-stent heeft een laag met antistoffen waardoor het behandelde bloedvat snel bedekt raakt met lichaamseigen cellen. Zo wordt tegengegaan dat er opnieuw een vernauwing optreedt of dat

Effect of Covered Metallic Stents Compared With Plastic Stents on Benign Biliary Stricture Resolution

Science.gov (United States)

Coté, Gregory A.; Slivka, Adam; Tarnasky, Paul; Mullady, Daniel K.; Elmunzer, B. Joseph; Elta, Grace; Fogel, Evan; Lehman, Glen; McHenry, Lee; Romagnuolo, Joseph; Menon, Shyam; Siddiqui, Uzma D.; Watkins, James; Lynch, Sheryl; Denski, Cheryl; Xu, Huiping; Sherman, Stuart

2017-01-01

IMPORTANCE Endoscopic placement of multiple plastic stents in parallel is the first-line treatment for most benign biliary strictures; it is possible that fully covered, self-expandable metallic stents (cSEMS) may require fewer endoscopic retrograde cholangiopancreatography procedures (ERCPs) to achieve resolution. OBJECTIVE To assess whether use of cSEMS is noninferior to plastic stents with respect to stricture resolution. DESIGN, SETTING, AND PARTICIPANTS Multicenter (8 endoscopic referral centers), open-label, parallel, randomized clinical trial involving patients with treatment-naive, benign biliary strictures (N = 112) due to orthotopic liver transplant (n = 73), chronic pancreatitis (n = 35), or postoperative injury (n = 4), who were enrolled between April 2011 and September 2014 (with follow-up ending October 2015). Patients with a bile duct diameter less than 6 mm and those with an intact gallbladder in whom the cystic duct would be overlapped by a cSEMS were excluded. INTERVENTIONS Patients (N = 112) were randomized to receive multiple plastic stents or a single cSEMS, stratified by stricture etiology and with endoscopic reassessment for resolution every 3 months (plastic stents) or every 6 months (cSEMS). Patients were followed up for 12 months after stricture resolution to assess for recurrence. MAIN OUTCOMES AND MEASURES Primary outcome was stricture resolution after no more than 12 months of endoscopic therapy. The sample size was estimated based on the noninferiority of cSEMS to plastic stents, with a noninferiority margin of −15%. RESULTS There were 55 patients in the plastic stent group (mean [SD] age, 57 [11] years; 17 women [31%]) and 57 patients in the cSEMS group (mean [SD] age, 55 [10] years; 19 women [33%]). Compared with plastic stents (41/48, 85.4%), the cSEMS resolution rate was 50 of 54 patients (92.6%), with a rate difference of 7.2% (1-sided 95% CI, −3.0% to ∞; P stents was rejected. The mean number of ERCPs to achieve resolution

Stent thrombosis, myocardial infarction, and death after drug-eluting and bare-metal stent coronary interventions

DEFF Research Database (Denmark)

Jensen, Lisette Okkels; Maeng, Michael; Kaltoft, Anne

2007-01-01

OBJECTIVES: The aim of the study was to examine outcomes subsequent to implantation of drug-eluting stents (DES) and bare-metal stents (BMS). BACKGROUND: Use of DES might be associated with increased risk of stent thrombosis (ST), myocardial infarction (MI), and death. METHODS: From January 2002...... through June 2005, data from all percutaneous coronary interventions in western Denmark were prospectively recorded in the Western Denmark Heart Registry; 12,395 consecutive patients (17,152 lesions) treated with stent implantation were followed for 15 months. Data on death and MI were ascertained from...... within 15 months after implantation of DES seems unlikely to outweigh the benefit of these stents. Udgivelsesdato: 2007-Jul-31...

Development and application of stent-based image guided navigation system for oral and maxillofacial surgery

Energy Technology Data Exchange (ETDEWEB)

Lee, Woo Jin; Kim, Dae Seung [Interdisciplinary Program in Radiation Applied Life Science, Dental Research Institute and BK21, College of Medicine, Seoul National University, Seoul (Korea, Republic of); Yi, Won Jin; Lee, Sam Sun; Choi, Soon Chul; Heo, Min Suk; Huh, Kyung Hoe; Kim, Myung Jin; Lee, Jee Ho [Department of Oral and Maxillofacial Surgery, Dental Research Institute, School of Dentistry, Seoul National University, Seoul (Korea, Republic of)

2009-09-15

The purpose of this study was to develop a stent-based image guided surgery system and to apply it to oral and maxillofacial surgeries for anatomically complex sites. We devised a patient-specific stent for patient-to-image registration and navigation. Three dimensional positions of the reference probe and the tool probe were tracked by an optical camera system and the relative position of the handpiece drill tip to the reference probe was monitored continuously on the monitor of a PC. Using 8 landmarks for measuring accuracy, the spatial discrepancy between CT image coordinate and physical coordinate was calculated for testing the normality. The accuracy over 8 anatomical landmarks showed an overall mean of 0.56 {+-} 0.16 mm. The developed system was applied to a surgery for a vertical alveolar bone augmentation in right mandibular posterior area and possible interior alveolar nerve injury case of an impacted third molar. The developed system provided continuous monitoring of invisible anatomical structures during operation and 3D information for operation sites. The clinical challenge showed sufficient accuracy and availability of anatomically complex operation sites. The developed system showed sufficient accuracy and availability in oral and maxillofacial surgeries for anatomically complex sites.

Tracheal obstruction caused by an expandable metallic stent: a case of successful removal of the stent.

Science.gov (United States)

Okuyama, Hiroomi; Kubota, Akio; Kawahara, Hisayoshi; Oue, Takaharu; Nose, Satoko; Ihara, Toshiyuki

2005-07-01

We report a case of tracheal obstruction caused by an expandable metallic stent. A 3-month-old girl with severe tracheomalacia had a placement of a Palmaz stent. At 3 years of age, she developed progressive dyspnea. The CT scan showed tracheal obstruction caused by granulation tissue over the stent. At operation, the stent was found to have penetrated the posterior tracheal wall. Under partial cardiopulmonary bypass, the stent was removed along with the membranous wall of the trachea, and the trachea was reconstructed using slide tracheoplasty. Tracheal obstruction is one of the serious complications caused by an expandable metallic stent. Direct open approach to the trachea under cardiopulmonary bypass is thought to be a safe way to manage this problem.

Absorbed power distribution in the whole-body system of a tractor operator

Directory of Open Access Journals (Sweden)

Jacek Kromulski

2016-06-01

The concept of absorbed power as a measurement for evaluation of WBV exposure opens a new area for research. The important character of absorbed power is that it has physical significance and therefore can be measured as well as computed analytically. The absorbed power relates to dissipation of energy attributed to relative motions of the visco-elastic tissues, muscles and skeletal system, which under prolonged exposures could lead to physical damage in the musculoskeletal system. A structural model of the human operator allows determination of the dynamic characteristics of the model, and study of the energy flow between the elements of the model.

Prospective Evaluation of Two iStent® Trabecular Stents, One iStent Supra® Suprachoroidal Stent, and Postoperative Prostaglandin in Refractory Glaucoma: 4-year Outcomes.

Science.gov (United States)

Myers, Jonathan S; Masood, Imran; Hornbeak, Dana M; Belda, Jose I; Auffarth, Gerd; Jünemann, Anselm; Giamporcaro, Jane Ellen; Martinez-de-la-Casa, Jose M; Ahmed, Iqbal Ike K; Voskanyan, Lilit; Katz, L Jay

2018-03-01

This study evaluates long-term outcomes of two trabecular micro-bypass stents, one suprachoroidal stent, and postoperative prostaglandin in eyes with refractory open angle glaucoma (OAG). Prospective ongoing 5-year study of 80 eligible subjects (70 with 4-year follow-up) with OAG and IOP ≥ 18 mmHg after prior trabeculectomy and while taking 1-3 glaucoma medications. Subjects received two iStent ® trabecular micro-bypass stents, one iStent Supra ® suprachoroidal stent, and postoperative travoprost. Postoperative IOP was measured with medication and annually following medication washouts. Performance was measured by the proportion of eyes with ≥ 20% IOP reduction on one medication (the protocol-specified prostaglandin) versus preoperative medicated IOP (primary outcome); and the proportion of eyes with postoperative IOP ≤ 15 and ≤ 18 mmHg on one medication (secondary outcome). Additional clinical and safety data included medications, visual field, pachymetry, gonioscopy, adverse events, visual acuity, and slit-lamp and fundus examinations. Preoperatively, mean medicated IOP was 22.0 ± 3.1 mmHg on 1.2 ± 0.4 medications, and mean unmedicated IOP was 26.4 ± 2.4 mmHg. Postoperatively, among eyes without later cataract surgery, mean medicated IOP at all visits through 48 months was ≤ 13.7 mmHg (≥ 37% reduction), and annual unmedicated IOP was ≤ 18.4 mmHg (reductions of ≥ 30% vs. preoperative unmedicated IOP and ≥ 16% vs. preoperative medicated IOP). At all postoperative visits among eyes without additional surgery or medication, ≥ 91% of eyes had ≥ 20% IOP reduction on one medication versus preoperative medicated IOP. At month 48, 97 and 98% of eyes achieved IOP ≤ 15 and ≤ 18 mmHg, respectively, on one medication. Six eyes required additional medication, no eyes required additional glaucoma surgery, and safety measurements were favorable throughout follow-up. IOP control was achieved safely with two

Safety and efficacy of everolimus-eluting stents for bare-metal in-stent restenosis

Energy Technology Data Exchange (ETDEWEB)

Ota, Hideaki [Division of Interventional Cardiology, MedStar Washington Hospital Center, Washington, DC 20010 (United States); Mahmoudi, Michael [University of Surrey, Guildford Road, Surrey, GU2-7XH (United Kingdom); Torguson, Rebecca; Satler, Lowell F.; Suddath, William O.; Pichard, Augusto D. [Division of Interventional Cardiology, MedStar Washington Hospital Center, Washington, DC 20010 (United States); Waksman, Ron, E-mail: ron.waksman@medstar.net [Division of Interventional Cardiology, MedStar Washington Hospital Center, Washington, DC 20010 (United States)

2015-04-15

Objective: The aim of this study was to compare the safety and efficacy of the everolimus-eluting stents (EES) with the paclitaxel-eluting stent (PES) and sirolimus-eluting stent (SES) for the treatment of bare-metal in-stent restenosis. Background: The optimal treatment for bare-metal in-stent restenosis remains controversial. Methods: The study cohort comprised 322 consecutive patients (543 lesions) who presented with bare-metal in-stent restenosis to our institution and underwent coronary artery stent implantation with EES (114 patients; 181 lesions), PES (65 patients; 116 lesions) and SES (143 patients; 246 lesions). The analyzed clinical parameters were the 1-year rates of death, Q-wave myocardial infarction (MI), target lesion revascularization (TLR), target vessel revascularization (TVR), definite stent thrombosis (ST) and major adverse cardiac events (MACE) defined as the composite of death, MI, or TLR at 1-year. Results: The three groups were well matched for the conventional risk factors except for age and chronic kidney disease. The 1-year analyzed clinical parameters were similar in the three groups: death (EES = 3.5%, PES = 4.6%, SES = 4.2%; p = 0.94), MI (EES = 3.5%, PES = 6.3%, SES = 2.1%; p = 0.31), TLR (EES = 9.8%, PES = 9.5%, SES = 5.7%; p = 0.42), TVR (EES = 14.3%, PES = 11.1%, SES = 11.3%; p = 0.74), definite ST (EES = 0.9%, PES = 3.1%, SES = 3.5%; p = 0.38) and MACE (EES = 14.0%, PES = 15.4%, SES = 10.5%; p = 0.54). Male gender (hazard ratio = 0.47; 95% confidence interval = 0.25–0.88) and number of treated lesions (hazard ratio = 1.47; 95% confidence interval = 1.06–2.05) were found to be independent predictors of MACE. Conclusion: The results of the present study indicate that EES may provide similar safety and efficacy as first generation DES for the treatment of patients presenting with bare-metal in-stent restenosis.

Cost analysis of prophylactic intraoperative cystoscopic ureteral stents in gynecologic surgery.

Science.gov (United States)

Fanning, James; Fenton, Bradford; Jean, Geraldine Marie; Chae, Clara

2011-12-01

Prophylactic intraoperative ureteral stent placement is performed to decrease operative ureteric injury, though few data are available on the effectiveness of this procedure, and no data are available on its cost. To analyze the cost of prophylactic intraoperative cystoscopic ureteral stents in gynecologic surgery. All cases of prophylactic ureteral stent placement performed in gynecologic surgery during a 1-year period were identified and retrospectively reviewed through the electronic medical records database of Summa Health System. Costs were obtained through the Healthcare Cost Accounting System. The principles of cost-effective analysis were used (ie, explicit and detailed descriptions of costs and cost-effectiveness statistics). Importantly, we evaluated cost and not charges or financial model estimates. In addition, we obtained the contribution margins (ie, the hospital's net profit or loss) for prophylactic ureteral stent placement. Other gynecologic procedures were also analyzed. Among 792 major inpatient gynecologic procedures, 18 cases of prophylactic intraoperative ureteral stents were identified. Median costs were as follows: additional cost of prophylactic intraoperative ureteral stenting, $1580; additional cost of surgical resources, $770; cost of ureteral catheters, $427; cost of surgeons, $383. The contribution margins per case for various gynecologic surgical procedures were as follows: oophorectomy, $2804 profit; abdominal hysterectomy, $2649 profit; laparoscopically assisted vaginal hysterectomy (LAVH), $1760 profit. When intraoperative ureteral stenting was added, the contribution margins changed to the following: oophorectomy, $782 profit; abdominal hysterectomy, $627 profit; LAVH, $262 loss. Overall, the contribution margin profit was decreased by about 85%, from $2400 to $380. Prophylactic intraoperative ureteral stenting in gynecologic surgery decreases a hospital's contribution margin. Because of the expense of this procedure, as well as

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

Science.gov (United States)

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

2016-06-01

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

Stenting in the treatment of acute ischemic stroke: literature review.

Directory of Open Access Journals (Sweden)

Edgar A Samaniego

2011-12-01

Full Text Available Recanalization of acute large artery occlusions is a strong predictor of good outcome. The development of thrombectomy devices resulted in a significant improvement in recanalization rates compared to thrombolytics alone. However, clinical trials and registries with these thrombectomy devices in acute ischemic stroke (AIS have shown recanalization rates in the range of 40-81%. The last decade has seen the development of nickel titanium self-expandable stents (SES. These stents, in contrast to balloon-mounted stents, allow better navigability and deployment in tortuous vessels and therefore are optimal for the cerebral circulation. SES were initially used for stent-assisted coil embolization of intracranial aneurysms and for treatment of intracranial stenosis. However, a few authors have recently reported feasibility of deployment of SES in AIS. The use of these devices yielded higher recanalization rates compared to traditional thrombectomy devices. Encouraged by these results, retrievable SES systems have been recently used in AIS. These devices offer the advantage of resheathing and retrieving of the stent even after full deployment. Some of these stents can also be detached in case permanent stent placement is needed. Retrievable SES are being used in Europe and currently tested in clinical trials in the United States. We review the recent literature in the use of stents for the treatment of AIS secondary to large vessel occlusion.

Stent Fracture and Reocclusion After Placement of a Single Self-Expanding Stent in the Common Iliac Artery and Endovascular Treatment

International Nuclear Information System (INIS)

Higashiura, Wataru; Sakaguchi, Shoji; Morimoto, Kengo; Kichikawa, Kimihiko

2008-01-01

We present a case of fracture of a single self-expanding stent placed in the common iliac artery (CIA). An 80-year-old woman underwent placement of a self-expanding stent for CIA occlusion. Stent fracture and reocclusion were detected after 18 months. Successful revascularization was achieved using a stent-in-stent maneuver. The possibility of stent fracture with reocclusion should be considered following treatment with a single self-expanding stent for CIA occlusion.

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

International Nuclear Information System (INIS)

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

2012-01-01

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.

Spectral Analysis Related to Bare-Metal and Drug-Eluting Coronary Stent Implantation

Energy Technology Data Exchange (ETDEWEB)

Silva, Rose Mary Ferreira Lisboa da, E-mail: roselisboa@cardiol.br [Faculdade de Medicina da UFMG, Divinópolis, MG (Brazil); Silva, Carlos Augusto Bueno [Faculdade de Medicina da UFMG, Divinópolis, MG (Brazil); Belo Horizonte, Hospital São João de Deus, Divinópolis, MG (Brazil); Greco, Otaviano José [Belo Horizonte, Hospital São João de Deus, Divinópolis, MG (Brazil); Moreira, Maria da Consolação Vieira [Faculdade de Medicina da UFMG, Divinópolis, MG (Brazil)

2014-08-15

The autonomic nervous system plays a central role in cardiovascular regulation; sympathetic activation occurs during myocardial ischemia. To assess the spectral analysis of heart rate variability during stent implantation, comparing the types of stent. This study assessed 61 patients (mean age, 64.0 years; 35 men) with ischemic heart disease and indication for stenting. Stent implantation was performed under Holter monitoring to record the spectral analysis of heart rate variability (Fourier transform), measuring the low-frequency (LF) and high-frequency (HF) components, and the LF/HF ratio before and during the procedure. Bare-metal stent was implanted in 34 patients, while the others received drug-eluting stents. The right coronary artery was approached in 21 patients, the left anterior descending, in 28, and the circumflex, in 9. As compared with the pre-stenting period, all patients showed an increase in LF and HF during stent implantation (658 versus 185 ms2, p = 0.00; 322 versus 121, p = 0.00, respectively), with no change in LF/HF. During stent implantation, LF was 864 ms2 in patients with bare-metal stents, and 398 ms2 in those with drug-eluting stents (p = 0.00). The spectral analysis of heart rate variability showed no association with diabetes mellitus, family history, clinical presentation, beta-blockers, age, and vessel or its segment. Stent implantation resulted in concomitant sympathetic and vagal activations. Diabetes mellitus, use of beta-blockers, and the vessel approached showed no influence on the spectral analysis of heart rate variability. Sympathetic activation was lower during the implantation of drug-eluting stents.

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

Science.gov (United States)

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

2017-02-01

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

The Incidence and Risk Factors of In-Stent Restenosis for Vertebrobasilar Artery Stenting.

Science.gov (United States)

Zheng, Dai; Mingyue, Zhu; Wei, Shi; Min, Li; Wanhong, Chen; Qiliang, Dai; Yongjun, Jiang; Xinfeng, Liu

2018-02-01

In-stent restenosis (ISR) remains a challenge for vertebrobasilar artery stenting (VBAS). We aimed to investigate the incidence and risk factors of ISR. This was a retrospective study. From July 28, 2005, to July 30, 2015, patients who received VBAS with an angiographic follow-up time of 6 to 12 months after surgery were enrolled. The clinical and angiographic issues were recorded and analyzed. In total, 283 patients with 335 stents were incorporated into the study. Vertebral ostial lesions accounted for 73.4% (246/335) of the lesions. During the follow-up period, 58 patients with 60 stents experienced ISR (>50%). Stepwise logistic regression analysis showed that the degree of residual stenosis, stent diameter, and alcohol consumption were independent predictors of ISR. Our study demonstrated the incidence and risk factors of ISR after VBAS. This retrospective study with the largest cohort to date provided insight into the occurrence of ISR after VBAS. Copyright © 2017 Elsevier Inc. All rights reserved.

Magnetizable stent-grafts enable endothelial cell capture

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Tefft, Brandon J. [Department of Cardiovascular Diseases, Mayo Clinic, Rochester, MN (United States); Uthamaraj, Susheil [Division of Engineering, Mayo Clinic, Rochester, MN (United States); Harburn, J. Jonathan [School of Medicine, Pharmacy and Health, Durham University, Stockton-on-Tees (United Kingdom); Hlinomaz, Ota [Department of Cardioangiology, St. Anne' s University Hospital, Brno (Czech Republic); Lerman, Amir [Department of Cardiovascular Diseases, Mayo Clinic, Rochester, MN (United States); Dragomir-Daescu, Dan [Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN (United States); Sandhu, Gurpreet S., E-mail: sandhu.gurpreet@mayo.edu [Department of Cardiovascular Diseases, Mayo Clinic, Rochester, MN (United States)

2017-04-01

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

Water heating solar system using collector with polycarbonate absorber surface

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Souza, Luiz Guilherme Meira de; Sodre, Dilton; Cavalcanti, Eduardo Jose Cidade; Souza, Luiz Guilherme Vieira Meira de; Mendes, Jose Ubiragi de Lima [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil)], e-mails: lguilherme@dem.ufrn.br, diltonsodre@ifba.edu.br, ubiragi@ct.ufrn.br

2010-07-01

It is presented s solar collector to be used in a heating water for bath system, whose main characteristics are low cost and easy fabrication and assembly processes. The collector absorber surface consists of a polycarbonate plate with an area of 1.5 m{sup 2}. The water inlet and outlet are made of PVC 50mm, and were coupled to a 6mm thick polycarbonate plate using fiberglass resin. A 200 liters thermal reservoir will be used. This reservoir is also alternative. The absorber heating system works under thermo-siphon regimen. Thermal parameters will be evaluated to prove the feasibility of the studied solar heating system to obtain bath water for a four people family. (author)

Covered stent placement for the treatment of malignant superior vena cava syndrome: Is unilateral covered stenting and effective?

International Nuclear Information System (INIS)

Cho, Young Hoon; Gwon, Dong Il; Ko, Gi Young; Ko, Heung Kyu; Kim, Jin Hyoung; Shin, Ji Hoon; Yoon, Hyun Ki; Sung, Kyu Bo

2014-01-01

To evaluate the safety and efficacy of unilateral covered stent placement in patients with malignant superior vena cava (SVC) syndrome. Between October 2008 and November 2012, expanded polytetrafluoroethylene-covered stent placement for malignant SVC syndrome was performed in 40 consecutive patients (35 men and five women; mean age, 61.4 years; range, 35-81 years). All covered stents were unilaterally placed within the SVC or across the venous confluence when needed to relieve venous obstruction and prevent tumor overgrowth, regardless of patency of contralateral brachiocephalic veins. Stent placement was technically successful in all patients. There were no major complications. Of the 37 patients symptomatic prior to stent placement, 34 (92%) experienced complete symptomatic relief 1-8 days after stent placement. Of the 29 patients who underwent covered stent placement across the venous confluence, nine patients had patent contralateral brachiocephalic veins prior to stent placement. However, no sign of SVC obstruction or contralateral upper extremity venous thrombosis was observed during the follow-up period. Kaplan-Meier analysis revealed median patient survival of 163 days. Stent occlusion occurred in four (10%) of 40 patents. Cumulative stent patency rates at 1, 3, 6, and 12 months were 95%, 92%, 86%, and 86%, respectively. Unilateral covered stent placement appears to be a safe and effective method for treating malignant SVC syndrome, despite the location of SVC occlusion.

Covered stent placement for the treatment of malignant superior vena cava syndrome: Is unilateral covered stenting and effective?

Energy Technology Data Exchange (ETDEWEB)

Cho, Young Hoon; Gwon, Dong Il; Ko, Gi Young; Ko, Heung Kyu; Kim, Jin Hyoung; Shin, Ji Hoon; Yoon, Hyun Ki; Sung, Kyu Bo [Dept. of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul (Korea, Republic of)

2014-02-15

To evaluate the safety and efficacy of unilateral covered stent placement in patients with malignant superior vena cava (SVC) syndrome. Between October 2008 and November 2012, expanded polytetrafluoroethylene-covered stent placement for malignant SVC syndrome was performed in 40 consecutive patients (35 men and five women; mean age, 61.4 years; range, 35-81 years). All covered stents were unilaterally placed within the SVC or across the venous confluence when needed to relieve venous obstruction and prevent tumor overgrowth, regardless of patency of contralateral brachiocephalic veins. Stent placement was technically successful in all patients. There were no major complications. Of the 37 patients symptomatic prior to stent placement, 34 (92%) experienced complete symptomatic relief 1-8 days after stent placement. Of the 29 patients who underwent covered stent placement across the venous confluence, nine patients had patent contralateral brachiocephalic veins prior to stent placement. However, no sign of SVC obstruction or contralateral upper extremity venous thrombosis was observed during the follow-up period. Kaplan-Meier analysis revealed median patient survival of 163 days. Stent occlusion occurred in four (10%) of 40 patents. Cumulative stent patency rates at 1, 3, 6, and 12 months were 95%, 92%, 86%, and 86%, respectively. Unilateral covered stent placement appears to be a safe and effective method for treating malignant SVC syndrome, despite the location of SVC occlusion.

Renal PTA stenting

International Nuclear Information System (INIS)

Tsetis, D.

2012-01-01

Full text: Renal artery stenosis (RAS) is a common condition that may lead to hypertension, progressive renal dysfunction and cardiovascular morbidity. Catheter-based therapy for symptomatic, haemodynamically significant, RAS has become the preferred method of revascularization. Balloon angioplasty has been the traditional treatment of choice for fibromuscular dysplasia, however stents are increasingly used for the treatment of atheromatous lesions; in many cases-such as in ostial lesions-, direct stenting is strongly indicated. Despite the increased use of endovascular therapy for renal artery stenosis, there is still controversy regarding the optimal management and the net benefit of this treatment. Several randomized trials of balloon angioplasty or stenting for renal artery stenosis compared with medical therapy alone have been conducted, however these could not show definite advantage of endovascular therapy. Problems encountered with those trials include enrollment of small number of patients, frequent crossover from medical to interventional therapy compromising the intention-to-treat results, or selection of patients that are not expected to show clear benefit. The Angioplasty and Stenting for Renal Artery Lesions (ASTRAL) is the most important of these trials; however, it,s study design was faulty and therefore did not provide conclusive evidence to answer the question of whether angioplasty and stenting or medical therapy is the best treatment for haemodynamically significant RAS. All expectations are now focused on the Cardiovascular Outcomes in Renal Atherosclerotic Lesions (CORAL) trial which was designed to answer the same question, and its methodologies took into consideration the weaknesses of the ASTRAL trial. Regarding stent device itself, it seems that the optimal design is probably a stainless steel, laser cut, open-cells stent mounted on a rapid exchange delivery balloon catheter compatible with 0.014-in and 0.018-in guidewire. As a future

”Missing clot” during mechanical thrombectomy in acute stroke using Solitaire stent retrieval system

Directory of Open Access Journals (Sweden)

Vikram Huded

2016-01-01

Full Text Available Stent retrieval system is an established treatment modality in acute ischemic stroke with large vessel occlusion. Here, we describe a complication which occurred during mechanical thrombectomy in three cases where the clot dislodged during retrieval. There was a possibility of the clot getting reinjected into the artery with possible dire consequences.

Influence of covered stent versus bare stent on long-term efficacy of transjugular intrahepatic portosystemic shunt: a meta-analysis

Directory of Open Access Journals (Sweden)

XU Lu

2016-10-01

Full Text Available Objective To investigate the long-term postoperative efficacy of transjugular intrahepatic portosystemic shunt (TIPS using polytetrafluoroethylene (PTFE-covered stent or bare stent, and to provide a basis of evidence-based medicine for the selection of stent in TIPS. Methods CBM, Wanfang Data, CNKI, VIP, MEDLINE, and PubMed were searched for controlled trials on TIPS in the treatment of cirrhotic portal hypertension published form 1989 to 2015; the studies which met the inclusion criteria were selected, and quality assessment was performed for these articles. RevMan 5.3 software was used to analyze the incidence rates of stent dysfunction and hepatic encephalopathy and 1-year survival rate after TIPS, and funnel plots were used to analyze publication bias. Results A total of 11 studies were included, consisting of 698 patients in PTFE-covered stent group and 1283 patients in bare stent group. The results of the meta-analysis showed that the PTFE-covered stent group showed a significantly lower incidence rate of stent dysfunction than the bare stent group (14.8% vs 47.0%, OR=0.18, 95% CI: 0.13-0.24, P＜0.001. There was no significant difference in the incidence rate of hepatic encephalopathy between the two groups (23.5% vs 25.7%, OR=0.88, 95% CI: 0.66-1.17, P=0.37. The PTFE-covered stent group had a significantly higher 1-year survival rate than the bare stent group (76.9% vs 62.7%, OR=2.10, 95% CI: 1.54-2.85, P＜0.001. The funnel plots which were plotted based on the incidence rates of stent dysfunction and hepatic encephalopathy and 1-year survival rate lacked symmetry, which suggested that a certain degree of publication bias might exist. Conclusion Compared with the bare stent, the PTFE-covered stent can improve stent dysfunction and 1-year survival rate after TIPS, while there is no significant change in the incidence rate of hepatic encephalopathy. Therefore, the PTFE-covered stent has certain advantages over the bare stent in TIPS. In

Long-Term Type 1 Diabetes Enhances In-Stent Restenosis after Aortic Stenting in Diabetes-Prone BB Rats

Directory of Open Access Journals (Sweden)

Geanina Onuta

2011-01-01

Full Text Available Type 1 diabetic patients have increased risk of developing in-stent restenosis following endovascular stenting. Underlying pathogenetic mechanisms are not fully understood partly due to the lack of a relevant animal model to study the effect(s of long-term autoimmune diabetes on development of in-stent restenosis. We here describe the development of in-stent restenosis in long-term (~7 months spontaneously diabetic and age-matched, thymectomized, nondiabetic Diabetes Prone BioBreeding (BBDP rats (n=6-7 in each group. Diabetes was suboptimally treated with insulin and was characterized by significant hyperglycaemia, polyuria, proteinuria, and increased HbA1c levels. Stented abdominal aortas were harvested 28 days after stenting. Computerized morphometric analysis revealed significantly increased neointima formation in long-term diabetic rats compared with nondiabetic controls. In conclusion, long-term autoimmune diabetes in BBDP rats enhances in-stent restenosis. This model can be used to study the underlying pathogenetic mechanisms of diabetes-enhanced in-stent restenosis as well as to test new therapeutic modalities.

Endotracheal expandable metallic stent placement in dogs

Energy Technology Data Exchange (ETDEWEB)

Sawada, S; Tanabe, Y; Fujiwara, Y; Koyama, T; Tanigawa, N; Kobayashi, M; Katsube, Y; Nakamura, H [Tottori Univ. School of Medicine, Yonago (Japan). Dept. of Radiology Research Inst. for Microbial Diseases, Osaka (Japan). Dept. of Radiology

1991-01-01

Various types of Gianturco zig-zag wire stent were implanted into the tracheas of 4 dogs to define the suitable characteristics of the endotracheal wire stent in these animals. These stents were constructed of 0.45, and 0.33 mm stainless steel wire. The diameter of the fully expanded stents was 3 cm and their lengths were 2, 3, and 4 cm. The 2 cm stent constructed of 0.33 mm wire showed minimum pathologic changes of the trachea of the dog compared to the other stents, and at the same time had a complete covering of ciliated columnar epithelium over the stent surface. (orig.).

Percutaneous coronary intervention with second-generation paclitaxel-eluting stents versus everolimus-eluting stents in United States contemporary practice (REWARDS TLX Trial).

Science.gov (United States)

Waksman, Ron; Ghali, Magdi; Goodroe, Randy; Ryan, Thomas; Turco, Mark; Ring, Michael; McGarry, Thomas; Dobies, David; Shammas, Nicolas; Steinberg, Daniel H; Swymelar, Stacy; Kaneshige, Kimberly; Torguson, Rebecca

2012-10-15

Registry Experience at the Washington Hospital Center, DES - Taxus Liberte Versus Xience V (REWARDS TLX) is a physician-initiated, retrospective, real-world, multicenter, observational study for all patients >18 years of age subjected to percutaneous coronary intervention with everolimus-eluting stents (EESs) or paclitaxel-eluting stents (PESs). Outcomes of patients receiving a TAXUS Liberté or XIENCE V drug-eluting stent were compared. Baseline clinical, procedural, and follow-up data at 12 months were collected from 10 clinical centers by an electronic data capture system. The study's primary end point was major adverse cardiac events: a composite of all-cause death, Q-wave myocardial infarction, target vessel revascularization, and stent thrombosis. The trial is registered with http://www.clinicaltrials.gov (NCT01134159). Data were entered for 1,195 patients (PES, n = 595; EES, n = 600). Baseline clinical characteristics were similar except for higher dyslipidemia, systemic hypertension, and family history of coronary artery disease in the EES group. In-hospital outcome was similar between groups, with an overall in-hospital stent thrombosis rate of 0.2%. The primary end point at 12 months was similar (EES 7.8% vs 10.8%, p = 0.082). Overall stent thrombosis rate was lower in the EES group (0.3% vs 1.2%, respectively, p = 0.107); however, target lesion revascularization was similar (PES, hazard ratio 1.46, 95% confidence interval 0.98 to 2.19, p = 0.064). There was no difference in overall mortality between groups. In conclusion, second-generation EESs and PESs demonstrated similar efficacy and safety profiles for broadened patient and lesion subsets compared to a selected population from the pivotal trials. However, for composite efficacy and safety end points, EESs outperformed second-generation PESs. Copyright © 2012 Elsevier Inc. All rights reserved.

Covered metal stent or multiple plastic stents for refractory pancreatic ductal strictures in chronic pancreatitis: a systematic review.

Science.gov (United States)

Shen, Yonghua; Liu, Mingdong; Chen, Min; Li, Yunhong; Lu, Ying; Zou, Xiaoping

2014-01-01

Refractory chronic pancreatitis has been proposed as a challenge for endoscopists following routine single plastic stenting. However, data on the efficacy and safety of further endoscopic stenting are still controversial. The current systematic review aimed to assess the efficacy and safety of placement of fully covered self-expandable metal stent (FCSEMS) and multiple plastic stents. Databases including MEDLINE, EMBASE, the Cochrane Library, CBM, CNKI, VIP, and WANFANG Database were used to search relevant trials. Published studies were assessed by using well-defined inclusion and exclusion criteria. The process was independently performed by two investigators. A total of 5 studies provided data of 80 patients. Forest plots and publication bias were not carried out because few studies were relevant and screened studies were all case series. The technical success rate was 100% both in placement of FCSEMS and multiple plastic stents. The functional success rate after placement of FCSEMS was 100%, followed by multiple plastic stents (94.7%). Complications occurred 26.2% after FCSEMS placement, which was not described in detail in multiple plastic stents. The stent migration rate was 8.2% for FCSEMS and 10.5% for multiple plastic stents. Reintervention rate was 9.8% for FCSEMS and 15.8% for multiple plastic stents. Pain improvement rate was 85.2% for FCSEMS and 84.2% for multiple plastic stents. FCSEMS appeared to be no significant difference with multiple plastic stents in treatment of refractory chronic pancreatitis. We need to develop more investigations. Copyright © 2014 IAP and EPC. Published by Elsevier B.V. All rights reserved.

Endoscopic ultrasound-guided biliary drainage using a newly designed metal stent with a thin delivery system: a preclinical study in phantom and porcine models.

Science.gov (United States)

Minaga, Kosuke; Kitano, Masayuki; Itonaga, Masahiro; Imai, Hajime; Miyata, Takeshi; Yamao, Kentaro; Tamura, Takashi; Nuta, Junya; Warigaya, Kenji; Kudo, Masatoshi

2017-12-08

This study was designed to evaluate the feasibility and safety of a newly designed self-expandable metal stent for endoscopic ultrasound-guided biliary drainage (EUS-BD) when it was delivered via three different stent delivery systems: a 7.5Fr delivery catheter with a bullet-shaped tip (7.5Fr-bullet), a 7Fr catheter with a bullet-shaped tip (7Fr-bullet), or a 7Fr catheter with a tee-shaped tip (7Fr-tee). This experimental study utilized a porcine model of biliary dilatation involving ten pigs. In the animal study, technical feasibility and clinical outcomes of the stent when placed with each of the delivery systems were examined. In addition, a phantom model was used to measure the resistance of these delivery systems to advancement. Phantom experiments showed that, compared with 7Fr-bullet, 7Fr-tee had less resistance force to the advancement of the stent delivery system. EUS-BD was technically successful in all ten pigs. Fistulous tract dilation was necessary in 100% (2/2), 75% (3/4), and 0% (0/4) of the pigs that underwent EUS-BD using 7.5Fr-bullet, 7Fr-bullet, and 7Fr-tee, respectively. There were no procedure-related complications. Our newly designed metal stent may be feasible and safe for EUS-BD, particularly when delivered by 7Fr-tee, because it eliminates the need for fistulous tract dilation.

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

Science.gov (United States)

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.

可吸收镁合金支架植入后犬冠状动脉C-反应蛋白、基质金属蛋白酶9和血管性血友病因子的表达%Effect of absorbable magnesium alloy stenting on expression of C-reactive protein, matrix metalloproteinase-9 and von Willebrand factor in dogs

Institute of Scientific and Technical Information of China (English)

王汝朋; 杨水祥

2015-01-01

BACKGROUND:Our previous study have verified the biosafety of absorbable magnesium aloy stents from a macro perspective. OBJECTIVE:To study the expressions of C-reactive protein, matrix metaloproteinase-9 and von Wilebrand factor in local vascular tissue after magnesium aloy stenting, and to explore the histocompatibility and safety of magnesium aloy stents at the molecular expression level. METHODS:Twenty-five absorbable magnesium aloy stents were implanted into the left anterior descending artery or circumflex artery of 25 epidemic prevention mongrel dogs. Five dogs with no stenting served as control group. Five dogs were sacrificed respectively at 24 hours, 3 days, 5 days, 1 week, 1 month after stenting, and vascular specimens were taken for preparation of pathological sections. The expressions of C-reactive protein, matrix metaloproteinase-9 and von Wilebrand factor within the coronary artery wal were determined by immunohistochemical staining method. RESULTS AND CONCLUSION: Compared with the control group, the number of cels positive for C-reactive protein, matrix metaloproteinase-9 and von Wilebrand factor was significantly increased at different times after stenting (P 0.01). The inflammatory reactions induced by absorbable magnesium aloy stents are slight and last for short time, which suggests that the absorbable magnesium aloy stents have good histocompatibility and safety.%背景：课题组前期研究从宏观角度验证了可吸收镁合金支架的生物安全性。目的：观察可吸收镁合金支架植入后局部血管组织C-反应蛋白、基质金属蛋白酶9及血管性血友病因子的表达情况，从分子表达水平深层次探讨镁合金支架的组织相容性及安全性。方法：将25枚可吸收镁合金支架植入25只防疫杂种犬冠状动脉前降支或左回旋支，未植入支架的5只犬冠状动脉作为正常对照组，支架植入后24 h、3 d、5 d、1周、1个月各处死动物5�

Self-expandable metal stents for obstructing colonic and extracolonic cancer

DEFF Research Database (Denmark)

van Hooft, Jeanin E; van Halsema, Emo E; Vanbiervliet, Geoffroy

2014-01-01

as a bridge to elective surgery is not recommended as a standard treatment of symptomatic left-sided malignant colonic obstruction (strong recommendation, high quality evidence). 3 For patients with potentially curable but obstructing left-sided colonic cancer, stent placement may be considered......, and Evaluation (GRADE) system was adopted to define the strength of recommendations and the quality of evidence. Main recommendations The following recommendations should only be applied after a thorough diagnostic evaluation including a contrast-enhanced computed tomography (CT) scan. 1 Prophylactic colonic...... stent placement is not recommended. Colonic stenting should be reserved for patients with clinical symptoms and imaging evidence of malignant large-bowel obstruction, without signs of perforation (strong recommendation, low quality evidence). 2 Colonic self-expandable metal stent (SEMS) placement...

Percutaneous Biliary Drainage Using Open Cell Stents for Malignant Biliary Hilar Obstruction

Energy Technology Data Exchange (ETDEWEB)

Ahn, Sun Jun; Bae, Jae Ik; Han, Tae Sun; Won, Je Hwan; Kim, Ji Dae; Kwack, Kyu Sung; Lee, Jae Hee; Kim, Young Chul [Dept. of Radiology, Ajou University School of Medicine, Suwon (Korea, Republic of)

2012-11-15

To evaluate the feasibility, safety and the effectiveness of the complex assembly of open cell nitinol stents for biliary hilar malignancy. During the 10 month period between January and October 2007, 26 consecutive patients with malignant biliary hilar obstruction underwent percutaneous insertion of open cell design nitinol stents. Four types of stent placement methods were used according to the patients' ductal anatomy of the hilum. We evaluated the technical feasibility of stent placement, complications, patient survival, and the duration of stent patency. Bilobar biliary stent placement was conducted in 26 patients with malignant biliary obstruction-T (n = 9), Y (n 7), crisscross (n = 6) and multiple intersecting types (n = 4). Primary technical success was obtained in 24 of 26 (93%) patients. The crushing of the 1st stent during insertion of the 2nd stent occurred in two cases. Major complications occurred in 2 of 26 patients (7.7%). One case of active bleeding from hepatic segmental artery and one case of sepsis after procedure occurred. Clinical success was achieved in 21 of 24 (87.5%) patients, who were followed for a mean of 141.5 days (range 25-354 days). The mean primary stent patency period was 191.8 days and the mean patient survival period was 299 days. Applying an open cell stent in the biliary system is feasible, and can be effective, especially in multiple intersecting stent insertions in the hepatic hilum.

Percutaneous Biliary Drainage Using Open Cell Stents for Malignant Biliary Hilar Obstruction

International Nuclear Information System (INIS)

Ahn, Sun Jun; Bae, Jae Ik; Han, Tae Sun; Won, Je Hwan; Kim, Ji Dae; Kwack, Kyu Sung; Lee, Jae Hee; Kim, Young Chul

2012-01-01

To evaluate the feasibility, safety and the effectiveness of the complex assembly of open cell nitinol stents for biliary hilar malignancy. During the 10 month period between January and October 2007, 26 consecutive patients with malignant biliary hilar obstruction underwent percutaneous insertion of open cell design nitinol stents. Four types of stent placement methods were used according to the patients' ductal anatomy of the hilum. We evaluated the technical feasibility of stent placement, complications, patient survival, and the duration of stent patency. Bilobar biliary stent placement was conducted in 26 patients with malignant biliary obstruction-T (n = 9), Y (n 7), crisscross (n = 6) and multiple intersecting types (n = 4). Primary technical success was obtained in 24 of 26 (93%) patients. The crushing of the 1st stent during insertion of the 2nd stent occurred in two cases. Major complications occurred in 2 of 26 patients (7.7%). One case of active bleeding from hepatic segmental artery and one case of sepsis after procedure occurred. Clinical success was achieved in 21 of 24 (87.5%) patients, who were followed for a mean of 141.5 days (range 25-354 days). The mean primary stent patency period was 191.8 days and the mean patient survival period was 299 days. Applying an open cell stent in the biliary system is feasible, and can be effective, especially in multiple intersecting stent insertions in the hepatic hilum.

Covered Balloon-Expanding Stents in Airway Stenosis.

Science.gov (United States)

Majid, Adnan; Kheir, Fayez; Chung, Jey; Alape, Daniel; Husta, Bryan; Oh, Scott; Folch, Erik

2017-04-01

The balloon-expanding stents are widely available but rarely described for use within the tracheobronchial tree. This report describes our experience with these stents in airway stenosis particularly as a lobar salvage therapy. This was a retrospective review of all records in which the balloon-expanding stents were used at a tertiary medical center. Ages, sex, location of stenosis, etiology of stenosis, stent size, duration of stent placement and associated interventions for airway stenosis were recorded. Patient's self-reported respiratory symptoms, dyspnea scale, and radiographic imaging at baseline and after stent placement were also reported. Twenty-one Atrium iCAST stents were inserted in 18 patients with malignant and benign airway disease. The median age was 69.5 years (interquartile range, 53.5 to 74). Most stents (n=20, 95%) were deployed in the lobar airways. There was a significant improvement in the modified Medical Research Council dyspnea scale from median of 3 to 2 (Pstent placement was achieved in 15 patients (83%). No deaths were related to airway stenting complications. Adverse events related to stents included migration (n=2, 9.5%), granulation tissue formation (n=2, 9.5%) and mucus plugging (n=1, 4.8%). Lobar stenting with balloon-expanding metallic stents appears feasible, safe and improves symptoms as well as radiographic atelectasis in patients with lobar airway stenosis in this small case series. Larger studies are needed to confirm this observation and to address long-term safety.

Novel 3D-CT evaluation of carotid stent volume: greater chronological expansion of stents in patients with vulnerable plaques.

Science.gov (United States)

Itami, Hisakazu; Tokunaga, Koji; Okuma, Yu; Hishikawa, Tomohito; Sugiu, Kenji; Ida, Kentaro; Date, Isao

2013-09-01

Although self-expanding carotid stents may dilate gradually, the degrees of residual stenosis have been quantified by the NASCET criteria, which is too simple to reflect the configuration of the stented artery. We measured the volumes of the stent lumens chronologically by 3D-CT in patients after carotid artery stenting (CAS), and analyzed the correlations between the volume change and medical factors. Fourteen patients with carotid artery stenosis were treated using self-expanding, open-cell stents. All patients underwent preoperative plaque MRI (magnetization-prepared rapid acquisition gradient-echo, MPRAGE) and chronological 3D-CT examinations of their stents immediately after their placement and 1 day, 1 week, and 1 month after the procedure. The volume of the stent lumen was measured using a 3D workstation. The correlations between stent volume and various factors including the presence of underlying diseases, plaque characteristics, and the results of the CAS procedure were analyzed. Stent volume gradually increased in each case and had increased by 1.04-1.55 (mean, 1.25)-fold at 1 postoperative month. The presence of underlying medical diseases, plaque length, the degree of residual stenosis immediately after CAS, and plaque calcification did not have an impact on the change in stent volume. On the other hand, the stent volume increase was significantly larger in the patients with vulnerable plaques that demonstrated high MPRAGE signal intensity (P stent volume. Self-expanding stents in carotid arteries containing vulnerable plaques expand significantly more than those without such plaques in a follow-up period.

Fluoroscopically guided placement of self-expandable metallic stents and stent-grafts in the treatment of acute malignant colorectal obstruction.

Science.gov (United States)

Kim, Honsoul; Kim, Seung Hyoung; Choi, Sun Young; Lee, Kwang-Hun; Won, Jong Yoon; Lee, Do Yun; Lee, Jong Tae

2008-12-01

To evaluate the technical feasibility and clinical effectiveness of fluoroscopically guided placement of self-expandable metallic stents and stent-grafts for acute malignant colorectal obstruction. Radiologic images and clinical reports of 42 patients (22 men, 20 women; age range, 28-93 years; median age, 65.5 years) who underwent fluoroscopically guided colorectal stent insertion without endoscopic assistance for acute malignant obstruction were reviewed retrospectively. Eighteen patients received bare stents as a bridge to surgery. Twenty-four patients received 27 insertions of either a bare stent (n = 15) or a stent-graft (n = 12) for palliation. The obstruction was located in the rectum (n = 8), sigmoid (n = 17), descending colon (n = 8), splenic flexure (n = 3), and transverse colon (n = 6). Clinical success, defined as more than 50% dilatation of the stent with subsequent symptomatic improvement, was achieved in 41 of the 42 patients (98%). No major procedure-related complications occurred. Minor complications occurred in eight of the 45 procedures (18%). No perioperative mortalities occurred within 1 month after surgery. In the palliative group, the median stent patency was 62 days (range, 0-1,014 days). There was no statistically significant difference in stent patency between the bare stents (range, 0-855 days; median, 68 days) and stent-grafts (range, 1-1,014 days; median, 81 days). Fluoroscopically guided placement of self-expandable metallic stents and stent-grafts for the relief of acute malignant colorectal obstruction was technically feasible without endoscopic assistance-even in lesions proximal to the splenic flexure and transverse colon-and clinically effective in both bridge to surgery and palliative management.

[Tracheobronchial stents: a retrospective analysis of indications, results and in particular complications].

Science.gov (United States)

Tonn, H; Mall, W; Schneider, K-D; Schönhofer, B

2008-10-01

Tracheobronchial stents are inserted mainly in cases of malignant and benign airway stenosis. Further indications are esophago-tracheal fistulas, mediastinal fistulas and tracheomalacia. A retrospective analysis was conducted on patients' records, information provided by the general practitioners and relatives of the patients from July 1993 to December 2006 in the Department of Pneumology of the Heidehaus Hospital Hannover (since 6/05 Department of Pneumology and Internal Intensive Care Medicine, Oststadt-Heidehaus Hospital). During the observation period of 13 years a total of 269 stents (177 permanent, 92 temporary) were implanted in 207 patients (1.3 stents per patient). The vast majority of patients (173/207) suffered from an underlying malignancy. About half of the stents were deployed in the trachea. The median length of placement was 116 days in patients with malignancies and 313 days in patients with benign diseases. In about 40 % of the patients notable complications were observed which were directly or indirectly associated with the stents. These findings show the importance of a critical indication for stent implantation. In benign diseases a stent can remain for years inside the tracheobronchial system, if it is well tolerated in the beginning. In malignant diseases the result depends decisively on the stage of the tumour: has the stent been implanted before any other tumour therapy is started or is it an end-stage tumor with no other therapeutic option? In general, complications of stents occur quite frequently. The analysis of stent data leads to some aspects for the prevention of stent-related complications. There should be a strict indication and appropriate choice of stent material. Nevertheless, there remains an ethical dilemma in patients with end-stage disease as to whether to implant a stent or to do nothing against the tumor, because the benefit immediately after stent insertion vanishes with progression of the tumour, so causing extra

Is quantitative coronary angiography reliable in assessing the late lumen loss of the everolimus-eluting bioresorbable polylactide scaffold in comparison with the cobalt-chromium metallic stent?

NARCIS (Netherlands)

Sotomi, Yohei; Onuma, Yoshinobu; Miyazaki, Yosuke; Asano, Taku; Katagiri, Yuki; Tenekecioglu, Erhan; Jonker, Hans; Dijkstra, Jouke; de Winter, Robbert J.; Wykrzykowska, Joanna J.; Stone, Gregg W.; Popma, Jeffrey J.; Kozuma, Ken; Tanabe, Kengo; Serruys, Patrick W.; Kimura, Takeshi

2017-01-01

Aims: Immediately after stent/scaffold implantation, quantitative coronary angiography (QCA) in comparison to optical coherence tomography (OCT) more severely underestimates the lumen diameter (LD) in Absorb than in XIENCE. This OCT-QCA discrepancy has not been evaluated at long-term follow-up. The

Outcomes of Endovascular Aneurysm Repair using the Ovation Stent Graft System in Adverse Anatomy.

Science.gov (United States)

Greaves, Nicholas S; Moore, Aiden; Seriki, Dare; Ghosh, Jonathan

2018-04-01

The aim was the evaluation of mid-term efficacy and safety outcome measures for the Ovation (Endologix, Santa Rosa, CA, USA) stent graft system in the management of infrarenal abdominal aortic aneurysms (iAAA) with adverse anatomy. A retrospective observational study of all patients undergoing elective iAAA repair was carried out from 2012 to 2017 using Ovation Prime or iX stent grafts with a minimum of 3 months follow-up at a single UK vascular centre. Post-operative surveillance involved computed tomography scans at 3 months and 1 year, with duplex ultrasound yearly thereafter. Outcome measures were established with retrospective analysis of pre- and post-operative imaging, and included peri-operative mortality, major adverse events, limb complications, aneurysm diameter change, and endoleak rates. All patients were within Ovation instructions for use (IFU), and assessment was made to determine whether aneurysms had anatomical features considered adverse for other commonly used stent graft platforms. Ovation stent grafts were implanted in 52 patients (79% male, mean age 75.7 years) with a mean aneurysm diameter of 62.5 mm (range 55-107 mm). There was 100% technical deployment success. The 30 day mortality was 0% and there was no aneurysm related mortality during follow-up (median 24 months, range 3-48 months). There were no type I or III endoleaks, but 19% developed type II endoleaks with one patient requiring re-intervention. No iliac limb occlusions were identified but one case required relining for limb kinking. All 52 cases were within the IFU for Ovation but only 12% met the IFU criteria for the Cook and Medtronic devices. The mid-term experience with Ovation demonstrates safe, durable treatment of iAAAs, including those with unfavourable anatomy, frequently off IFU for other commonly used devices. Copyright © 2017 European Society for Vascular Surgery. Published by Elsevier B.V. All rights reserved.

Changes in the mechanical environment of stenotic arteries during interaction with stents: computational assessment of parametric stent designs.

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Holzapfel, Gerhard A; Stadler, Michael; Gasser, Thomas C

2005-02-01

Clinical studies have identified factors such as the stent design and the deployment technique that are one cause for the success or failure of angioplasty treatments. In addition, the success rate may also depend on the stenosis type. Hence, for a particular stenotic artery, the optimal intervention can only be identified by studying the influence of factors such as stent type, strut thickness, geometry of the stent cell, and stent-artery radial mismatch with the wall. We propose a methodology that allows a set of stent parameters to be varied, with the aim of evaluating the difference in the mechanical environment within the wall before and after angioplasty with stenting. Novel scalar quantities attempt to characterize the wall changes inform of the contact pressure caused by the stent struts, and the stresses within the individual components of the wall caused by the stent. These quantities are derived numerically and serve as indicators, which allow the determination of the correct size and type of the stent for each individual stenosis. In addition, the luminal change due to angioplasty may be computed as well. The methodology is demonstrated by using a full three-dimensional geometrical model of a postmortem specimen of a human iliac artery with a stenosis using imaging data. To describe the material behavior of the artery, we considered mechanical data of eight different vascular tissues, which formed the stenosis. The constitutive models for the tissue components capture the typical anisotropic, nonlinear and dissipative characteristics under supra-physiological loading conditions. Three-dimensional stent models were parametrized in such a way as to enable new designs to be generated simply with regard to variations in their geometric structure. For the three-dimensional stent-artery interaction we use a contact algorithm based on smooth contact surfaces of at least C-continuity, which prevents numerical problems known from standard facet-based contact

Retreatment of recanalized aneurysms after Y-stent-assisted coil embolization with double enterprise stents: case report and systematic review of the literature.

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Kono, Kenichi; Shintani, Aki; Terada, Tomoaki

2014-01-01

It is necessary to consider possibility of recanalization and retreatment after coil embolization for cerebral aneurysms. There is concern that retreatment for recanalized aneurysms after Y-stent-assisted coil embolization may be difficult because of double stents, especially in Y-stents with double closed-cell stents owing to narrowed structures. However, no detailed reports of retreatment after Y-stent have been reported. Between July 2010 and June 2013, we treated four aneurysms with Y-stent-assisted coil embolization using Enterprise closed-cell stents. Recanalization occurred in one case (25%), and retreatment was performed. We easily navigated a microcatheter into the target portions of the aneurysm through the Y-stent and occluded the aneurysm with coils. Additionally, by systematically searching in PubMed, we found 105 cases of Y-stent-assisted coil embolization using Enterprise stents or Neuroform stents with more than 6 months of follow-up. Among them, retreatment was performed in 10 cases (9.5%). There were no significant differences in retreatment rates among different stent combinations (P=0.91; Fisher's exact test). In conclusion, navigation of a microcatheter into the aneurysm through the Y-stent with double Enterprise stents was feasible, and retreatment rates after Y-stent-assisted coiling may not depend on stent combinations.

Angioplasty and stent placement - carotid artery

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... medlineplus.gov/ency/article/002953.htm Angioplasty and stent placement - carotid artery To use the sharing features ... to remove plaque buildup ( endarterectomy ) Carotid angioplasty with stent placement Description Carotid angioplasty and stenting (CAS) is ...

Magnetic stents retain nanoparticle-bound antirestenotic drugs transported by lipid microbubbles.

Science.gov (United States)

Räthel, T; Mannell, H; Pircher, J; Gleich, B; Pohl, U; Krötz, F

2012-05-01

Coating coronary stents with antirestenotic drugs revolutionized interventional cardiology. We developed a system for post-hoc drug delivery to uncoated stents. We coupled rapamycin or a chemically similar fluorescent dye to superparamagnetic nanoparticles. The antiproliferative activity of rapamycin coupled to nanoparticles was confirmed in vitro in primary porcine vascular cells. The particles were then incorporated into lipid based microbubbles. Commercially available stents were made magnetizable by nickel plating and used to induce strong field gradients in order to capture magnetic microbubbles from flowing liquids when placed in an external magnetic field. Nanoparticle bound Rapamycin dose dependently inhibited cell proliferation in vitro. Magnetic microcbubbles carrying coated nanoparticles were caught by magnets placed external to a flow-through tube. Plating commercial stents with nickel resulted in increased deposition at stent struts and allowed for widely increased distance of external magnets. Deposition depended on circulation time and velocity and distance of magnets. Deposited microbubbles were destroyed by ultrasound and delivered their cargo to targeted sites. Drugs can be incorporated into nanoparticle loaded microbubbles and thus be delivered to magnetizable stents from circulating fluids by applying external magnetic fields. This technology could allow for post-hoc drug coating of already implanted vascular stents.

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

Science.gov (United States)

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

2002-03-01

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

Endobronchial Occlusion Stent: A Preliminary Experimental Study

Energy Technology Data Exchange (ETDEWEB)

Choi, Yo Won; Jeong, Woo Kyoung; Lee, Seoung Hoon; Heo, Jeong Nam; Jeon, Seok Chol [Hanyang University College of Medicine, Seoul (Korea, Republic of); Ko, Gi Young; Song, Ho Young [University of Ulsan College of Medicine, Ulsan (Korea, Republic of)

2010-04-15

To evaluate the safety and the technical feasibility of the use of an endobronchial occlusion stent and to get preliminary data for the development of the optimal material required for endobronchial occlusions. A commercialized, self-expandable tracheobronchial stent was modified; one half had a polyurethane cover with an occluded end and the other half was uncovered with a flaring configuration. The occluded end was placed such that it would face the distal lung. Under fluoroscopic guidance, seven stents were placed at the lower lobar bronchus in 6 mini-pigs. The bronchial obstruction was examined immediately after stent placement. Chest radiographs were taken at days 1, 7, 14, and 28 after stent placement and the removed airways from two, two, one, and one mini-pigs sacrificed on corresponding days were examined for the maintenance of bronchial obstruction. Stents were successfully placed and induced the immediate bronchial obstruction in all mini-pigs. Five of seven airways with occlusion stents maintained an obstruction until the mini-pigs were sacrificed. Proximal stent migration occurred in two mini-pigs (29%), and pulmonary consolidations were observed distal to four of the stents (57%). The placement of an endobronchial occlusion stent and the obstruction of targeted bronchi seem to be feasible, but an add-on check valve should be considered to prevent stent migration and obstructive pneumonia

Carotid Angioplasty and Stenting

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Carotid angioplasty and stenting Overview Carotid angioplasty (kuh-ROT-id AN-jee-o-plas-tee) and stenting ... to better see and examine the blood vessels. Food and medications You'll receive instructions on what ...

Supera self-expanding stents for endovascular treatment of femoropopliteal disease: a review of the clinical evidence

Directory of Open Access Journals (Sweden)

Bishu K

2015-07-01

Full Text Available Kalkidan Bishu,1,2 Ehrin J Armstrong1,21Division of Cardiology, University of Colorado, Aurora, 2Denver VA Medical Center, Denver, CO, USAAbstract: Femoropopliteal lesions account for a significant proportion of endovascular interventions for peripheral artery disease in patients with disabling claudication or chronic limb ischemia. The femoropopliteal artery crosses two joint structures (hip and knee joints and courses through the muscular adductor canal in the thigh, which places the artery at increased biomechanical stress. There is a critical need for stent platforms with a reduced risk of stent fracture while maintaining patency during long-term follow-up. The Supera peripheral stent system has a braided nickel–titanium alloy stent designed to withstand the unique stressors along the course of the femoropopliteal artery. This design may be associated with improved patency in association with reduced stent fracture rates on short- and medium-term follow-up. Further studies, including randomized controlled studies, comparing the Supera interwoven nickel–titanium alloy stent system with other stent platforms and angioplasty alone are needed.Keywords: peripheral artery disease, femoropopliteal atherosclerosis, SUPERA interwoven nitinol stent, stent fracture

Self-Expandable Metallic Stent Placement in Malignant Gastric Outlet Obstruction: A Comparison Between 2 Brands of Stents.

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Ye, Bing-Wei; Lee, Kuei-Chuan; Hsieh, Yun-Cheng; Li, Chung-Pin; Chao, Yee; Hou, Ming-Chih; Lin, Han-Chieh

2015-07-01

Malignant gastric outlet obstruction is a late complication of intraabdominal malignancy. Self-expandable metallic stent placement has been a safe palliative treatment to relieve obstructive symptoms. We aimed to assess the efficacy and safety of metallic stents in our patients and analyzed the clinical outcome of different brands. Seventy-one patients with inoperable gastric outlet obstruction receiving WallFlex enteral stents (WallFlex group) or Bonastents (Bonastent group) since April 2010 were analyzed retrospectively. The overall technical and clinical success rates of stent placement were 100% and 93%, respectively. The baseline characteristics and clinical outcomes including procedure-related complications, restenosis, and reintervention rates were comparable between the 2 groups. However, the Bonastent group had a higher rate of stent fracture than the WallFlex group (13.3% vs 0%, P = 0.03). The mean duration of overall stent patency was 132.7 days. The mean duration of survival was 181.9 days. Resumption of regular diet or low residual diet at day 7 after stent insertion predicted stent patency (hazard ratio [HR]: 0.28, P = 0.01). Cancer with gastric origin (HR: 0.25, P = 0.045) and poststent chemotherapy (HR: 0.38, P = 0.006) predicted lower mortality; however, peritoneal carcinomatosis (HR: 3.09, P = 0.04) correlated with higher mortality. Metallic stent placement is a safe and effective method for relieving gastric outlet obstruction. Except higher rate of stent fracture in the Bonastent group, there is no significant difference in clinical outcomes between the Bonastent group and the WallFlex group.

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

Science.gov (United States)

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

2018-05-30

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

Clinical and angiographic outcomes after stent-assisted coiling of cerebral aneurysms with Enterprise and Neuroform stents: a comparative analysis of the literature.

Science.gov (United States)

King, Brent; Vaziri, Sasha; Singla, Amit; Fargen, Kyle M; Mocco, J

2015-12-01

The most widely used intracranial stents for stent-assisted coiling are Neuroform (NEU) and Enterprise stents (ENT). This study compares published outcomes between the ENT and NEU coil-assist systems and comments on the published safety and efficacy of stent-assisted coiling in general. A literature search was performed through PubMed for all published series of ENT or NEU stent-assisted coiling of cerebral aneurysms from 2004 to 2014. All studies including 10 or more published cases of stent-assisted coiling with ENT or NEU were included. 47 studies met the inclusion criteria, containing 4238 aneurysms in 4039 patients. 2111 aneurysms were treated with NEU and 2127 were treated with ENT. Mean follow-up was 14.1 months. Overall, thromboembolic events occurred in 6.4% of aneurysms, intracranial hemorrhage (ICH) in 2.6%, permanent morbidity in 3.9%, and mortality in 2.3%. Initial and final 100% angiographic occlusion was seen in 53% and 69% of patients, respectively. Deployment failures (pstent-assisted coiling devices to date, containing over 4200 aneurysms in more than 4000 patients. Comparative analyses demonstrate that both devices are reported to be safe and effective with comparable permanent morbidity. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Dual-Source CT Angiography of Peripheral Arterial Stents: In Vitro Evaluation of 22 Different Stent Types

Directory of Open Access Journals (Sweden)

Michael Köhler

2011-01-01

Full Text Available Purpose. To test different peripheral arterial stents using four image reconstruction approaches with respect to lumen visualization, lumen attenuation and image noise in dual-source multidetector row CT (DSCT in vitro. Methods and Materials. 22 stents (nitinol, steel, cobalt-alloy, tantalum, platinum alloy were examined in a vessel phantom. All stents were imaged in axial orientation with standard parameters. Image reconstructions were obtained with four different convolution kernels. To evaluate visualization characteristics of the stent, the lumen diameter, intraluminal density and noise were measured. Results. The mean percentage of the visible stent lumen diameter from the nominal stent diameter was 74.5% ± 5.7 for the medium-sharp kernel, 72.8% ± 6.4 for the medium, 70.8% ± 6.4 for the medium-smooth and 67.6% ± 6.6 for the smooth kernel. Mean values of lumen attenuation were 299.7HU ± 127 (medium-sharp, 273.9HU ± 68 (medium, 270.7HU ± 53 (medium-smooth and 265.8HU ± 43. Mean image noise was: 54.6 ± 6.3, 20.5 ± 1.7, 16.3 ± 1.7, 14.0 ± 2 respectively. Conclusion. Visible stent lumen diameter varies depending on stent type and scan parameters. Lumen diameter visibility increases with the sharpness of the reconstruction kernel. Smoother kernels provide more realistic density measurements inside the stent lumen and less image noise.

Direct stent puncture technique for intraluminal stent recanalization in the superficial femoral and popliteal arteries in-stent occlusion: Outcomes from a prospective clinical analysis of diabetics with critical limb ischemia

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

2013-07-15

Purpose: To evaluate the efficacy and safety of “Direct Stent Puncture” technique for intraluminal stent recanalization in the femoro-popliteal segments. Methods and Materials: A cohort of diabetics who had symptomatic in-stent occlusion of the superficial femoral or popliteal arteries underwent endovascular recanalization. After antegrade failure, direct stent puncture technique was performed. The primary end-point was to efficacy assessment, intended as technical success and clinical improvement. The secondary end-point was safety assessment, intended as free of complication rate. Results: Fifty-four patients (37 men; 73.6 ± 8.5 years) underwent direct stent puncture technique, after several unsuccessful antegrade attempts to cross the occluded stent. Technical success for intraluminal stent recanalization was achieved in 53/54 (98.2%) of cases and failed in 1/54 (1.8%). Clinical improvement was obtained in 51/54 (94.4%) of cases, with regression of the clinical symptoms and improvement of the TcPO{sub 2}, from 3 ± 18 mmHg to 43 ± 11 mmHg after 15 days (p < 0.001). Free of complications rate was 92.5%. In 2/54 (3.7%) of cases distal embolization occurred, in 1/54 (1.9%) case a sudden vessel thrombosis was diagnosed after 12 hours and in 1/54 (1.9%) case hematoma at the stent puncture site was observed. Conclusions: Direct Stent Puncture technique is an efficacy and safety option for intraluminal stent recanalization in the femoro-popliteal segment in-stent occlusion.

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

Science.gov (United States)

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

2015-05-01

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

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

Science.gov (United States)

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

2018-02-01

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

Development and application of stent-based image guided navigation system for oral and maxillofacial surgery

International Nuclear Information System (INIS)

Lee, Woo Jin; Kim, Dae Seung; Yi, Won Jin; Lee, Sam Sun; Choi, Soon Chul; Heo, Min Suk; Huh, Kyung Hoe; Kim, Myung Jin; Lee, Jee Ho

2009-01-01

The purpose of this study was to develop a stent-based image guided surgery system and to apply it to oral and maxillofacial surgeries for anatomically complex sites. We devised a patient-specific stent for patient-to-image registration and navigation. Three dimensional positions of the reference probe and the tool probe were tracked by an optical camera system and the relative position of the handpiece drill tip to the reference probe was monitored continuously on the monitor of a PC. Using 8 landmarks for measuring accuracy, the spatial discrepancy between CT image coordinate and physical coordinate was calculated for testing the normality. The accuracy over 8 anatomical landmarks showed an overall mean of 0.56 ± 0.16 mm. The developed system was applied to a surgery for a vertical alveolar bone augmentation in right mandibular posterior area and possible interior alveolar nerve injury case of an impacted third molar. The developed system provided continuous monitoring of invisible anatomical structures during operation and 3D information for operation sites. The clinical challenge showed sufficient accuracy and availability of anatomically complex operation sites. The developed system showed sufficient accuracy and availability in oral and maxillofacial surgeries for anatomically complex sites.

Predictors of the patency of self-expandable metallic stents in malignant gastroduodenal obstruction.

Science.gov (United States)

Kim, Seung Han; Chun, Hoon Jai; Yoo, In Kyung; Lee, Jae Min; Nam, Seung Joo; Choi, Hyuk Soon; Kim, Eun Sun; Keum, Bora; Seo, Yeon Seok; Jeen, Yoon Tae; Lee, Hong Sik; Um, Soon Ho; Kim, Chang Duck

2015-08-14

To investigate the predictive factors of self-expandable metallic stent patency after stent placement in patients with inoperable malignant gastroduodenal obstruction. A total of 116 patients underwent stent placements for inoperable malignant gastroduodenal obstruction at a tertiary academic center. Clinical success was defined as acceptable decompression of the obstructive lesion within the malignant gastroduodenal neoplasm. We evaluated patient comorbidities and clinical statuses using the World Health Organization's scoring system and categorized patient responses to chemotherapy using the Response Evaluation Criteria in Solid Tumors criteria. We analyzed the relationships between possible predictive factors and stent patency. Self-expandable metallic stent placement was technically successful in all patients (100%), and the clinical success rate was 84.2%. In a multivariate Cox proportional hazards model, carcinoembryonic antigen (CEA) levels were correlated with a reduction in stent patency [P = 0.006; adjusted hazard ratio (aHR) = 2.92, 95%CI: 1.36-6.25]. Palliative chemotherapy was statistically associated with an increase in stent patency (P = 0.009; aHR = 0.27, 95%CI: 0.10-0.72). CEA levels can easily be measured at the time of stent placement and may help clinicians to predict stent patency and determine the appropriate stent procedure.

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

Science.gov (United States)

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

2016-07-01

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

Exclusion of Atherosclerotic Plaque from the Circulation Using Stent-Grafts: Alternative to Carotid Stenting with a Protection Device?

International Nuclear Information System (INIS)

Peynircioglu, Bora; Geyik, Serdar; Yavuz, Kivilcim; Cil, Barbaros E.; Saatci, Isil; Cekirge, Saruhan

2007-01-01

Purpose. To retrospectively assess the feasibility, safety, and clinical mid-term outcome of patients undergoing carotid artery stenting with stent-grafts. Methods. Over a 4 year period stent-grafts were used in the endovascular treatment of symptomatic internal carotid artery stenosis in 12 patients (2 women, 10 men, aged 47-83 (mean 64) years). Protection devices were not used. Possible microembolic complications were evaluated by magnetic resonance imaging (MRI) examinations of the brain before and the day after the procedure in all patients. Mean follow-up was 22 months (range 1-42 months), by Doppler ultrasonography and conventional angiography as well as clinical examination .Results. The technical success rate was 100%. A total of 13 coronary stent-grafts were used. The mean stenosis rate (in terms of diameter) was 85% and the mean length of stent-grafts used was 20.9 mm. The mean diameter to which the stent-grafts were dilated was 4.66 mm. In-hospital complications occurred in 1 patient who suffered a minor femoral access hematoma that did not require transfusion or surgical decompression. Post-stenting diffusion-weighted MRI revealed several ipsilateral silent microemboli in only 1 case, which was completely asymptomatic. Two patients had a major stroke after 2 years of follow-up. Restenosis was found in 2 patients who underwent successful balloon dilatation followed by placement of a self-expandable bare stent within the stent-grafts. Conclusions. Stent-grafts may prevent microembolic complications during stenting of atherosclerotic carotid lesions in selected cases, offering immediate exclusion of the atherosclerotic lesion from the circulation by pressing the plaque against the vessel wall. Comparative, randomized studies in larger series of patients are needed with carotid-dedicated stent-graft designs

Endovascular treatment of experimentally induced aneurysms in rabbits using stents: a feasibility study

International Nuclear Information System (INIS)

Hans, F.J.; Thiex, R.; Gilsbach, J.M.; Krings, T.; Moeller-Hartmann, W.; Dreeskamp, H.; Stein, K.P.; Meetz, A.; Thron, A.; Pfeffer, J.; Scherer, K.; Brunn, A.

2003-01-01

Although Guglielmi detachable coil (GDC) systems have been generally accepted for treatment of intracranial aneurysms, primary stenting of aneurysms using porous stents or implantation of coils after stent placement remains experimental. Testing of these new methods requires an animal model which imitates human aneurysms in size, configuration and neck morphology. We assessed in detail the technical requirements of and steps for transfemoral stent treatment of experimentally induced aneurysms at the top of the brachiocephalic trunk in rabbits. We created aneurysms in ten rabbits by distal ligation and intraluminal digestion of the right common carotid artery with elastase. We treated five animals with porous stents alone, and five with stents plus coiling via the meshes of the stent, which permitted dense packing of coils. No complications related to the procedures occurred. In all animals, even in those treated solely with porous stents, total occlusion of the aneurysm was achieved. Our animal model can be suitable for testing the biocompatibility and occlusion rate of new methods and devices for the treatment of experimental aneurysms. (orig.)

Integrity of neutron-absorbing components of LWR fuel systems

International Nuclear Information System (INIS)

Bailey, W.J.; Berting, F.M.

1991-03-01

A study of the integrity and behavior of neutron-absorbing components of light-water (LWR) fuel systems was performed by Pacific Northwest Laboratory (PNL) and sponsored by the US Department of Energy (DOE). The components studies include control blades (cruciforms) for boiling-water reactors (BWRs) and rod cluster control assemblies for pressurized-water reactors (PWRs). The results of this study can be useful for understanding the degradation of neutron-absorbing components and for waste management planning and repository design. The report includes examples of the types of degradation, damage, or failures that have been encountered. Conclusions and recommendations are listed. 84 refs

Functional Nanoarchitectures For Enhanced Drug Eluting Stents

Science.gov (United States)

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

2017-01-01

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

Stent Thrombosis With Drug-Eluting Stents and Bioresorbable Scaffolds: Evidence From a Network Meta-Analysis of 147 Trials.

Science.gov (United States)

Kang, Si-Hyuck; Chae, In-Ho; Park, Jin-Joo; Lee, Hak Seung; Kang, Do-Yoon; Hwang, Seung-Sik; Youn, Tae-Jin; Kim, Hyo-Soo

2016-06-27

This study sought to perform a systematic review and network meta-analysis to compare the relative safety and efficacy of contemporary DES and BVS. To improve outcomes of patients undergoing percutaneous coronary revascularization, there have been advances in the design of drug-eluting stents (DES), including the development of drug-eluting bioresorbable vascular scaffolds (BVS). Prospective, randomized, controlled trials comparing bare-metal stents (BMS), paclitaxel-eluting stents (PES), sirolimus-eluting stents (SES), Endeavor zotarolimus-eluting stents (E-ZES), cobalt-chromium (CoCr) everolimus-eluting stents (EES), platinum-chromium (PtCr)-EES, biodegradable polymer (BP)-EES, Resolute zotarolimus-eluting stents (R-ZES), BP biolimus-eluting stents (BP-BES), hybrid sirolimus-eluting stents (H [Orsiro]-SES), polymer-free sirolimus- and probucol-eluting stents, or BVS were searched in online databases. The primary endpoint was definite or probable stent thrombosis at 1 year. A total of 147 trials including 126,526 patients were analyzed in this study. All contemporary DES were superior to BMS and PES in terms of definite or probable stent thrombosis at 1 year. CoCr-EES, PtCr-EES, and H-SES were associated with significantly lower risk than BVS. CoCr-EES and H-SES were superior to SES and BP-BES. The risk of myocardial infarction was significantly lower with H-SES than with BVS. There were no significant differences regarding all-cause or cardiac mortality. Contemporary devices including BVS showed comparably low risks of repeat revascularization. Contemporary DES, including biocompatible DP-DES, BP-DES, and polymer-free DES, showed a low risk of definite or probable stent thrombosis at 1 year. BVS had an increased risk of device thrombosis compared with CoCr-EES, PtCr-EES, and H-SES. Data from extended follow-up are warranted to confirm the long-term safety of contemporary coronary devices. Copyright © 2016 American College of Cardiology Foundation. Published by

Low-profile stent system for treatment of atherosclerotic renal artery stenosis : The GREAT trial

NARCIS (Netherlands)

Sapoval, Marc; Zahringer, Markus; Pattynama, Peter; Rabbia, Claudio; Vignali, Claudio; Maleux, Geert; Boyer, Louis; Szczerbo-Trojanowska, Malgorzata; Jaschke, Werner; Hafsahl, Geir; Downes, Mark; Beregi, Jean Paul; Veeger, Nic; Talen, Aly

PURPOSE: The Palmaz Genesis Peripheral Stainless Steel Balloon Expandable Stent in Renal Artery Treatment (GREAT) Trial was designed to assess the safety and performance of a low-profile stent for the treatment of obstructive renal artery disease by looking at 6-month renal artery patency uniformly

Magnetizable stent-grafts enable endothelial cell capture

Science.gov (United States)

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

2017-04-01

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

Impact on outcome of different types of carotid stent: results from the European Registry of Carotid Artery Stenting.

Science.gov (United States)

Stabile, Eugenio; Giugliano, Giuseppe; Cremonesi, Alberto; Bosiers, Marc; Reimers, Bernhard; Setacci, Carlo; Cao, Piergiorgio; Schmidt, Andrej; Sievert, Horst; Peeters, Patrick; Nikas, Dimitrios; Sannino, Anna; de Donato, Gianmarco; Parlani, Giambattista; Castriota, Fausto; Hornung, Marius; Rubino, Paolo; Esposito, Giovanni; Tesorio, Tullio

2016-06-12

Conflicting data exist on the impact on outcome of the use of different stent types during carotid artery stenting (CAS). The aim of this study was to evaluate clinical outcomes according to different carotid stent design among the population of the European Registry of Carotid Artery Stenting (ERCAS). The present study was conducted in 1,604 patients who underwent neuroprotected CAS in ERCAS. All types of commercially available carotid stent were used. Open-cell design stents were classified according to free cell area into 7.5 mm2. A total of 713 closed-cell, 456 hybrid-cell, 238 7.5 mm2 open-cell stents were implanted. Overall, the 30-day stroke and death rate was 1.37%. At 30 days, 19 strokes occurred (1.18%): eight in the group of patients treated with a closed-cell (1.12%), two in those with a hybrid-cell (0.44%), three in those with a 7.5 mm2 open-cell stent (3.05%) (p=0.045). Data of the present study suggest that, in the setting of neuroprotected CAS performed in high-volume centres by properly trained operators, the use of an open-cell design stent with a free cell area >7.5 mm2 may be associated with an increased 30-day stroke risk.

Investigation of adverse events associated with an off-label use of arterial stents and CE-marked iliac vein stents in the iliac vein: insights into developing a better iliac vein stent.

Science.gov (United States)

Shida, Takuya; Umezu, Mitsuo; Iwasaki, Kiyotaka

2018-06-01

We analyzed the adverse events associated with an off-label use of arterial stents and CE-marked iliac vein stents for the treatment of iliac venous thromboembolism and investigated their relationships with the anatomical features of the iliac vein, to gain insights into the development of a better iliac vein stent. Reports of adverse events following the use of stents in the iliac vein were retrieved from the Manufacturer and User Facility Device Experience (MAUDE) database that contain suspected device-associated complications reported to the Food and Drug Administration. Data from 2006 to 2016 were investigated. The literature analysis was also conducted using PubMed, Cochrane Library, EMBASE, and Web of Science focusing on English articles published up to 4 October 2016. The analysis of 88 adverse events from the MAUDE database and 182 articles from the literature revealed that a higher number of adverse events had been reported following the use of arterial stents in the iliac vein compared to CE-marked iliac vein stents. While stent migration and shortening were reported only for the arterial stents, stent fracture and compression occurred regardless of the stent type, even though a vein does not pulsate. A study of the anatomical features of the iliac vein implies that bending, compression, and kink loads are applied to the iliac vein stents in vivo. For designing, developing, and pre-clinical testing of stents intended for use in the iliac vein, the above mechanical load environments induced by the anatomical features should be considered.

Use of guiding sheaths in peroral fluoroscopic gastroduodenal stent placement

International Nuclear Information System (INIS)

Bae, Jae-Ik; Shin, Ji Hoon; Song, Ho-Young; Yoon, Chang Jin; Nam, Deok Ho; Choi, Won-Chan; Lim, Jin-Oh

2005-01-01

Our purpose was to assess the safety and usefulness of guiding sheaths in peroral fluoroscopic gastroduodenal stent placement. Two types of guiding sheath were made from straight polytetrafluoroethylene tubes. Type A was 80 cm in length, 4 mm in outer diameter and 3 mm in inner diameter. Type B was 70 cm in length, 6 mm in outer diameter and 5 mm in inner diameter. The type A sheath was used in 18 patients in whom a catheter-guide wire combination failed to pass through a stricture. The type B sheath was used in 22 patients in whom a stent delivery system failed to pass through the stricture due to loop formation within the gastric lumen. The overall success rate for guiding a catheter-guide wire through a stricture after using the type A sheath was 89%. The overall success rate for passing a stent delivery system through a stricture after using the type B sheath was 100%. All procedures were tolerated by the patients without any significant complications. The guiding sheaths were safe and useful in peroral fluoroscopic gastroduodenal stent placement. (orig.)

Acute ST-Elevation Myocardial Infarction after Coronary Stent Fracture.

Science.gov (United States)

Rafighdust, Abbasali; Eshraghi, Ali

2015-10-27

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

Nitinol Esophageal Stents: New Designs and Clinical Indications

International Nuclear Information System (INIS)

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

1996-01-01

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

A mechanical analysis of woodpecker drumming and its application to shock-absorbing systems

International Nuclear Information System (INIS)

Yoon, Sang-Hee; Park, Sungmin

2011-01-01

A woodpecker is known to drum the hard woody surface of a tree at a rate of 18 to 22 times per second with a deceleration of 1200 g, yet with no sign of blackout or brain damage. As a model in nature, a woodpecker is studied to find clues to develop a shock-absorbing system for micromachined devices. Its advanced shock-absorbing mechanism, which cannot be explained merely by allometric scaling, is analyzed in terms of endoskeletal structures. In this analysis, the head structures (beak, hyoid, spongy bone, and skull bone with cerebrospinal fluid) of the golden-fronted woodpecker, Melanerpes aurifrons, are explored with x-ray computed tomography images, and their shock-absorbing mechanism is analyzed with a mechanical vibration model and an empirical method. Based on these analyses, a new shock-absorbing system is designed to protect commercial micromachined devices from unwanted high-g and high-frequency mechanical excitations. The new shock-absorbing system consists of close-packed microglasses within two metal enclosures and a viscoelastic layer fastened by steel bolts, which are biologically inspired from a spongy bone contained within a skull bone encompassed with the hyoid of a woodpecker. In the experimental characterizations using a 60 mm smoothbore air-gun, this bio-inspired shock-absorbing system shows a failure rate of 0.7% for the commercial micromachined devices at 60 000 g, whereas a conventional hard-resin method yields a failure rate of 26.4%, thus verifying remarkable improvement in the g-force tolerance of the commercial micromachined devices.

Serial Versus Direct Dilation of Small Diameter Stents Results in a More Predictable and Complete Intentional Transcatheter Stent Fracture: A PICES Bench Testing Study.

Science.gov (United States)

Crystal, Matthew A; Morgan, Gareth J; Danon, Saar; Gray, Robert G; Gruenstein, Daniel H; Gordon, Brent M; Goldstein, Bryan H

2018-01-01

Balloon-expandable stents, implanted in infants and children with congenital heart disease (CHD), often require redilation to match somatic growth. Small diameter stents may eventually require longitudinal surgical transection to prevent iatrogenic vascular stenosis. Intentional transcatheter stent fracture (TSF) is an emerging alternative approach to stent transection, but little is known about the optimal stent substrate and best protocol to improve the likelihood of successful TSF. Bench testing was performed with a stent dilation protocol. After recording baseline characteristics, stents were serially or directly dilated using ultra-high-pressure balloons (UHPB) until fracture occurred or further stent dilation was not possible. Stent characteristics recorded were as follows: cell design, metallurgy, mechanism, and uniformity of fracture. Stents tested included bare-metal coronary stents, premounted small diameter stents, and ePTFE-covered small diameter premounted stents. Ninety-four stents representing 9 distinct models were maximally dilated, with 80 (85%) demonstrating evidence of fracture. Comprehensive fracture details were recorded in 64 stents: linear and complete in 34/64 stents (53.1%), linear and incomplete in 9/64 stents (14.1%), transverse/complex and complete in 6/64 stents (9.4%), and transverse/complex and incomplete in 15/64 stents (23.4%). Stent fracture was not accomplished in some stent models secondary to significant shortening, i.e., "napkin-ring" formation. Serial dilation resulted in evidence of fracture in 62/67 (92.5%) stents compared with 18/27 (66.7%) stents in the direct dilation group (p = 0.003). Intentional TSF is feasible in an ex vivo model. Serial dilation more reliably expanded the stent and allowed for ultimate stent fracture, whereas direct large diameter dilation of stents was more likely to generate a "napkin-ring" configuration, which may be more resistant to fracture. In vivo animal and human testing is necessary to

Anchoring barbs and balloon expandable stents: what is the risk of perforation and failed stent deployment?

Science.gov (United States)

Bown, M J; Harrison, G J; How, T V; Brennan, J A; Fisher, R K; Vallabhaneni, S R; McWilliams, R G

2012-09-01

Balloon expandable stents may on occasion be deployed in close proximity to the anchoring barbs of endovascular grafts. The aim of this study was to determine the risk and effect of balloon perforation by anchoring barbs and to assess whether these risks are different if the balloon is protected by a covered stent mounted upon it. A bench-top model was developed to mimic the penetration of anchoring barbs into the lumen of medium sized blood vessels. The model allowed variation of angle and depth of vessel penetration. Both bare balloons and those with covered stents mounted upon them were tested in the model to determine whether there was a risk of perforation and which factors increased or decreased this risk. All combinations of barb angle and depth caused balloon perforation but this was most marked when the barb was placed perpendicular to the long axis of the balloon. When the deployment of covered stents was attempted balloon perforation occurred in some cases but full stent deployment was achieved in all cases where the perforation was in the portion of the balloon covered by the stent. The only situation in which stent deployment failed was where the barb was intentionally placed in the uncovered portion of the balloon. This resulted in only partial deployment of the stent. Balloon rupture is a distinct possibility when deploying balloon-expandable stents in close proximity to anchoring barbs. Care should be taken in this circumstance to ensure that the barb is well away from the uncovered portion of the balloon. Copyright © 2012 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

First-in-human evaluation of a bioabsorbable polymer-coated sirolimus-eluting stent: imaging and clinical results of the DESSOLVE I Trial (DES with sirolimus and a bioabsorbable polymer for the treatment of patients with de novo lesion in the native coronary arteries).

Science.gov (United States)

Ormiston, John; Webster, Mark; Stewart, James; Vrolix, Mathias; Whitbourn, Robert; Donohoe, Dennis; Knape, Charlene; Lansky, Alexandra; Attizzani, Guilherme F; Fitzgerald, Peter; Kandzari, David E; Wijns, William

2013-10-01

This first-in-human multicenter study sought to examine prospectively the safety and efficacy of a new, cobalt chromium thin-strut, coronary absorbable polymer-coated, sirolimus-eluting stent. Bioabsorbable polymers on drug-eluting stents may lower the long-term risks of inflammation, delayed healing, and adverse events. We enrolled patients with symptomatic coronary artery disease with stable or unstable angina pectoris and >50% diameter stenosis, amenable to coverage with a ≤23-mm long stent in a vessel 2.5 to 3.5 mm in diameter. All patients received dual antiplatelet therapy after implantation. Patients, in groups of 10, underwent repeat angiography, intravascular ultrasound, and optical coherence tomography at 4, 6, or 8 months, and all patients were seen or contacted at 18 months of follow-up. The median (range) in-stent late lumen loss (LLL) was 0.03 mm (-0.22 to 0.21 mm), 0.10 mm (-0.03 to 1.2 mm), and 0.08 mm (-0.01 to 0.28 mm), at 4, 6, and 8 months, respectively. At 18 months, the median in-stent LLL was 0.08 mm (-0.30 to 0.46 mm). On optical coherence tomography, the proportion of uncovered stent struts decreased from a median of 7.3% (range 0.4% to 46.3%) at 4 months to 0% (range: 0% to 3.4%) at 18 months. The percentage of neointimal volume obstruction by intravascular ultrasound increased from a median of 5.3% to 9.1% between 4 and 6 months and remained nearly unchanged thereafter through 18 months of follow-up. The only recorded major adverse cardiac event was a myocardial infarction. At 18 months of follow-up, this absorbable polymer-coated, cobalt chromium sirolimus-eluting stent was associated with a low and stable in-stent LLL, complete strut coverage, and no stent thrombosis. (First-In-Human Trial of the MiStent Drug-Eluting Stent [DES] in Coronary Artery Disease [DESSOLVE-I]; NCT01247428). Copyright © 2013 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Investigation Of Interaction Between Nitinol Stent And A Vascular Plaque Using Finite Element Method

Directory of Open Access Journals (Sweden)

Recep Güneş

2012-06-01