Efficacy of SMART Stent Placement for Salvage Angioplasty in Hemodialysis Patients with Recurrent Vascular Access Stenosis

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Shingo Hatakeyama

2011-01-01

Full Text Available Vascular access stenosis is a major complication in hemodialysis patients. We prospectively observed 50 patients in whom 50 nitinol shape-memory alloy-recoverable technology (SMART stents were used as salvage therapy for recurrent peripheral venous stenosis. Twenty-five stents each were deployed in native arteriovenous fistula (AVF and synthetic arteriovenous polyurethane graft (AVG cases. Vascular access patency rates were calculated by Kaplan-Meier analysis. The primary patency rates in AVF versus AVG at 3, 6, and 12 months were 80.3% versus 75.6%, 64.9% versus 28.3%, and 32.3% versus 18.9%, respectively. The secondary patency rates in AVF versus AVG at 3, 6, and 12 months were 88.5% versus 75.5%, 82.6% versus 61.8%, and 74.4% versus 61.8%, respectively. Although there were no statistically significant difference in patency between AVF and AVG, AVG showed poor tendency in primary and secondary patency. The usefulness of SMART stents was limited in a short period of time in hemodialysis patients with recurrent vascular access stenosis.

Exact measurement of vascular lumina in digital subtraction arteriography (DSA) during stent implantations and percutaneous transluminal angioplasty (PTA)

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Pfluger, T [Dept. of Radiology, Univ. of Munich (Germany); Kueffer, G [Dept. of Radiology, Univ. of Munich (Germany); Hahn, D [Dept. of Radiology, Univ. of Munich (Germany)

1992-06-01

There are inherent difficulties in using high-resolution DSA in interventional radiology for measuring vascular luminal diameter since enlargement ratios are not constant. We present a system that permits accurate determination of vascular lumen diameters by means of a special angiographic catheter with predefined marking points. The accuracy of this measuring method was explored in tests using phantoms. In vivo practicability of the method was proved in PTA and stent implantations in 39 patients. This method with a maximum error of measurement of 5% appears to provide adequate safety in the choice of suitable dilating balloons and stents in interventional vascular procedures. In follow-up, it permits the accurate measurement of neo-intimal thickness. (orig.)

Perspective: carotid stenting and the history of disruptive technology in vascular surgery.

Science.gov (United States)

Veith, Frank J

2008-06-01

This article defines disruptive technology and discusses such technologies in Vascular Surgery. It considers the question: Is carotid artery stenting (CAS) a disruptive technology? Although CAS will impact positively on the treatment of carotid bifurcation disease, it will probably never displace carotid endarterectomy in the majority of patients. The precise role of CAS remains to be determined.

Process development for high-resolution 3D-printing of bioresorbable vascular stents

Science.gov (United States)

Ware, Henry Oliver T.; Farsheed, Adam C.; van Lith, Robert; Baker, Evan; Ameer, Guillermo; Sun, Cheng

2017-02-01

The recent development of "continuous projection microstereolithography" also known as CLIP technology has successfully alleviated the main obstacles surrounding 3D printing technologies: production speed and part quality. Following the same working principle, we further developed the μCLIP process to address the needs for high-resolution 3D printing of biomedical devices with micron-scale precision. Compared to standard stereolithography (SLA) process, μCLIP fabrication can reduce fabrication time from several hours to as little as a few minutes. μCLIP can also produce better surface finish and more uniform mechanical properties than conventional SLA, as each individual "fabrication layer" continuously polymerizes into the subsequent layer. In this study, we report the process development in manufacturing high-resolution bioresorbable stents using our own μCLIP system. The bioresorbable photopolymerizable biomaterial (B-ink) used in this study is methacrylated poly(1, 12 dodecamethylene citrate) (mPDC). Through optimization of our μCLIP process and concentration of B-ink components, we have created a customizable bioresorbable stent with similar mechanical properties exhibited by nitinol stents. Upon optimization, fabricating a 2 cm tall vascular stent that comprises 4000 layers was accomplished in 26.5 minutes.

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 experimental study on the influence of new spiral stent(Hanaro) on the vascular structures

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Park, Jae Hyung; Chung, Jin Wook; Jeong, Yoong Ki; Kook, Myeong Cherl; Seo, Jung Wook [Seoul National Univ. College of Medicine, Seoul (Korea, Republic of); Lim, Myung Kwan [Inha Univ. College of Medicine, Incheon (Korea, Republic of)

1996-06-01

The purpose of this study was to evaluate basic experimental data for the clinical application of a self-expandable stainless steel intravascular Hanaro spiral stent. For evaluation of the physical properties of the Hanaro stent, hoop strength, radioopacity, longitudinal flexibility, and foreshortening were measured. Twelve intravascular hanaro spiral stents were placed in the infrarenal abdominal aorta (n=6) and common iliac artery (n=6) in six mongrel dogs. Angiography and light microscopic examination were performed after one, two and eight months of placement of the stents. The stent had good radioopacity and was deployed with minimal foreshortening. hoop strength of a 6 mm-interval bend was found to be superior to that of 8 mm- and 10 mm-bend stent. On angiography the patency rate and thrombosis rate were 100% and 0% in the abdominal aorta and 50% in the common iliac artery, respectively. Minimal corrosion was seen in all stents, and they appeared to be biocompatible. The stent wires were covered with well-developed neointima which after one month had mostly fibroblast and collagen tissue ; the thickness of the neointima increased gradually during a period of eight months. At the end of that period, collagen fibres in the neointima were denser and showed a more paralled configuration than at one month. The Hanaro stent has good physical properties and also has a high patency rate, and good biocompatibilities. The stent may therefore be reliably and safely deployed in the human vascular system.

Distinctive effects of CD34- and CD133-specific antibody-coated stents on re-endothelialization and in-stent restenosis at the early phase of vascular injury

Science.gov (United States)

Wu, Xue; Yin, Tieying; Tian, Jie; Tang, Chaojun; Huang, Junli; Zhao, Yinping; Zhang, Xiaojuan; Deng, Xiaoyan; Fan, Yubo; Yu, Donghong; Wang, Guixue

2015-01-01

It is not clear what effects of CD34- and CD133-specific antibody-coated stents have on re-endothelialization and in-stent restenosis (ISR) at the early phase of vascular injury. This study aims at determining the capabilities of different coatings on stents (e.g. gelatin, anti-CD133 and anti-CD34 antibodies) to promote adhesion and proliferation of endothelial progenitor cells (EPCs). The in vitro study revealed that the adhesion force enabled the EPCs coated on glass slides to withstand flow-induced shear stress, so that allowing for the growth of the cells on the slides for 48 h. The in vivo experiment using a rabbit model in which the coated stents with different substrates were implanted showed that anti-CD34 and anti-CD133 antibody-coated stents markedly reduced the intima area and restenosis than bare mental stents (BMS) and gelatin-coated stents. Compared with the anti-CD34 antibody-coated stents, the time of cells adhesion was longer and earlier present in the anti-CD133 antibody-coated stents and anti-CD133 antibody-coated stents have superiority in re-endothelialization and inhibition of ISR. In conclusion, this study demonstrated that anti-CD133 antibody as a stent coating for capturing EPCs is better than anti-CD34 antibody in promoting endothelialization and reducing ISR. PMID:26813006

A Zr-based bulk metallic glass for future stent applications: Materials properties, finite element modeling, and in vitro human vascular cell response.

Science.gov (United States)

Huang, Lu; Pu, Chao; Fisher, Richard K; Mountain, Deidra J H; Gao, Yanfei; Liaw, Peter K; Zhang, Wei; He, Wei

2015-10-01

Despite the prevalent use of crystalline alloys in current vascular stent technology, new biomaterials are being actively sought after to improve stent performance. In this study, we demonstrated the potential of a Zr-Al-Fe-Cu bulk metallic glass (BMG) to serve as a candidate stent material. The mechanical properties of the Zr-based BMG, determined under both static and cyclic loadings, were characterized by high strength, which would allow for the design of thinner stent struts to improve stent biocompatibility. Finite element analysis further complemented the experimental results and revealed that a stent made of the Zr-based BMG was more compliant with the beats of a blood vessel, compared with medical 316L stainless steel. The Zr-based BMG was found to be corrosion resistant in a simulated body environment, owing to the presence of a highly stable ZrO2-rich surface passive film. Application-specific biocompatibility studies were conducted using human aortic endothelial cells and smooth muscle cells. The Zr-Al-Fe-Cu BMG was found to support stronger adhesion and faster coverage of endothelial cells and slower growth of smooth muscle cells than 316L stainless steel. These results suggest that the Zr-based BMG could promote re-endothelialization and potentially lower the risk of restenosis, which are critical to improve vascular stent implantation integration. In general, findings in this study raised the curtain for the potential application of BMGs as future candidates for stent applications. Vascular stents are medical devices typically used to restore the lumen of narrowed or clogged blood vessel. Despite the clinical success of metallic materials in stent-assisted angioplasty, post-surgery complications persist due to the mechanical failures, corrosion, and in-stent restenosis of current stents. To overcome these hurdles, strategies including new designs and surface functionalization have been exercised. In addition, the development of new materials with

Improving hemocompatibility and accelerating endothelialization of vascular stents by a copper-titanium film

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Liu, Hengquan, E-mail: 99xyxy@163.com [College of Materials and Chemistry & Chemical Engineering, Chengdu University of Technology, Chengdu 610059 (China); Pan, Changjiang [Jiangsu Provincial Key Laboratory for Interventional Medical Devices, Huaiyin Institute of Technology, Huaiyin 223033 (China); Zhou, Shijie; Li, Junfeng [College of Materials and Chemistry & Chemical Engineering, Chengdu University of Technology, Chengdu 610059 (China); Huang, Nan [Key Laboratory for Advanced Technologies of Materials, Ministry of Education, Southwest Jiaotong University, Chengdu 610031 (China); Dong, Lihua [Department of Research & Development, Lifetech Scientific (Shenzhen) Co., Ltd, Shenzhen 518057 (China)

2016-12-01

Bio-inorganic films and drug-eluting coatings are usually used to improve the hemocompatibility and inhibit restenosis of vascular stent; however, above bio-performances couldn't combine together with single materials. In the present study, we reported a simple approach to fabricate a metal film with the aim of imparting the stent with good blood compatibility and accelerating endothelialization. The films with various ratios of Cu and Ti were prepared through the physical vapor deposition. Phase structure and element composition were investigated by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), respectively. The releasing volume of copper ion in Cu/Ti film was determined by immersing test. The hemolysis ratio, platelet adhesion and clotting time were applied to evaluate the hemocompatibility. The proliferative behaviors of endothelial cells and smooth muscle cells under certain copper concentration were investigated in vitro and in vivo. Results indicated that copper-titanium films exhibited good hemocompatibility in vitro; however, the increase of Cu/Ti ratio could lead to increasing hemolysis ratio. Endothelial cells displayed more proliferative than smooth muscle cells when the copper concentration was < 7.5 μg/ml, however both cells tended to apoptosis to some degree when the copper concentration was increased. The complete endothelialization of the film with low copper in vivo was observed at the 2nd week, indicating that the copper-titanium film with the lower copper concentration could promote endothelialization. Therefore, the inorganic copper-titanium film could be potential biomaterials to improve blood compatibility and accelerating endothelialization of vascular stents. - Highlight: • The Cu/Ti film with regulating the various responses of ECs and SMCs has been prepared. • The hemocompatibility of Cu/Ti film is favorable and regulatable. • The volume of copper ion released from film could be designed. �

Statistical characteristics of surface integrity by fiber laser cutting of Nitinol vascular stents

International Nuclear Information System (INIS)

Fu, C.H.; Liu, J.F.; Guo, Andrew

2015-01-01

Graphical abstract: - Highlights: • Precision kerf with tight tolerance of Nitinol stents can be cut by fiber laser. • No HAZ in the subsurface was detected due to large grain size. • Recast layer has lower hardness than the bulk. • Laser cutting speed has a higher influence on surface integrity than laser power. - Abstract: Nitinol alloys have been widely used in manufacturing of vascular stents due to the outstanding properties such as superelasticity, shape memory, and superior biocompatibility. Laser cutting is the dominant process for manufacturing Nitinol stents. Conventional laser cutting usually produces unsatisfactory surface integrity which has a significant detrimental impact on stent performance. Emerging as a competitive process, fiber laser with high beam quality is expected to produce much less thermal damage such as striation, dross, heat affected zone (HAZ), and recast layer. To understand the process capability of fiber laser cutting of Nitinol alloy, a design-of-experiment based laser cutting experiment was performed. The kerf geometry, roughness, topography, microstructure, and hardness were studied to better understand the nature of the HAZ and recast layer in fiber laser cutting. Moreover, effect size analysis was conducted to investigate the relationship between surface integrity and process parameters.

Statistical characteristics of surface integrity by fiber laser cutting of Nitinol vascular stents

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Fu, C.H., E-mail: cfu5@crimson.ua.edu [Dept of Mechanical Engineering, The University of Alabama, Tuscaloosa, AL 35487 (United States); Liu, J.F. [Dept of Mechanical Engineering, The University of Alabama, Tuscaloosa, AL 35487 (United States); Guo, Andrew [Dept of Mechanical Engineering, The University of Alabama, Tuscaloosa, AL 35487 (United States); College of Arts and Science, Vanderbilt University, Nashville, TN 37235 (United States)

2015-10-30

Graphical abstract: - Highlights: • Precision kerf with tight tolerance of Nitinol stents can be cut by fiber laser. • No HAZ in the subsurface was detected due to large grain size. • Recast layer has lower hardness than the bulk. • Laser cutting speed has a higher influence on surface integrity than laser power. - Abstract: Nitinol alloys have been widely used in manufacturing of vascular stents due to the outstanding properties such as superelasticity, shape memory, and superior biocompatibility. Laser cutting is the dominant process for manufacturing Nitinol stents. Conventional laser cutting usually produces unsatisfactory surface integrity which has a significant detrimental impact on stent performance. Emerging as a competitive process, fiber laser with high beam quality is expected to produce much less thermal damage such as striation, dross, heat affected zone (HAZ), and recast layer. To understand the process capability of fiber laser cutting of Nitinol alloy, a design-of-experiment based laser cutting experiment was performed. The kerf geometry, roughness, topography, microstructure, and hardness were studied to better understand the nature of the HAZ and recast layer in fiber laser cutting. Moreover, effect size analysis was conducted to investigate the relationship between surface integrity and process parameters.

The Precise Determination of Vascular Lumen and Stent Diameters: Correlation Among Calibrated Angiography, Intravascular Ultrasound, and Pressure-Fixed Specimens

International Nuclear Information System (INIS)

Froelich, Jens J.; Hoppe, Martin; Nahrstedt, Christoph; Barth, Klemens H.; Wagner, H. Joachim; Klose, Klaus J.

1997-01-01

Purpose: Luminal diameters measured in vivo by calibrated-catheter angiography and by intravascular ultrasound were correlated with those obtained from pressure-fixed histologic cross-sections to determine the accuracy of both methods. Methods: Angiographic and endosonographic diameter measurements were performed in the center of stents placed in the iliac arteries of 10 miniature pigs and were compared with luminal and stent diameters in postmortem, pressure-fixed, histologic cross-sections from identical locations. Results: Compared with histologic diameters, magnification-corrected angiographic measurements still magnified vascular luminal diameters by 0.7 ± 0.71 mm (r= 0.41, Pearson; p 0.5, Wilcoxon, matched pairs). Similarly, stent diameters correlated well between endosonographic and histologic measurements (r= 0.91; p= 0.002), and less well between angiographic and histologic diameters (r= 0.62; p= 0.002). Conclusion: Since calibrated angiography still overestimates vascular lumina, endosonography is the preferred technique for accurate in vivo measurements

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

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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.

Coronary Artery Stent Evaluation Using a Vascular Model at 64-Detector Row CT: Comparison between Prospective and Retrospective ECG-Gated Axial Scans

International Nuclear Information System (INIS)

Suzuki, Shigeru; Furui, Shigeru; Kaminaga, Tatsuro; Miyazawa, Akiyoshi; Ueno, Yasunari; Konno, Kumiko; Kuwahara, Sadatoshi; Mehta, Dhruv

2009-01-01

We wanted to evaluate the performance of prospective electrocardiogram (ECG)-gated axial scans for assessing coronary stents as compared with retrospective ECG-gated helical scans. As for a vascular model of the coronary artery, a tube of approximately 2.5-mm inner diameter was adopted and as for stents, three (Bx-Velocity, Express2, and Micro Driver) different kinds of stents were inserted into the tube. Both patent and stenotic models of coronary artery were made by instillating different attenuation (396 vs. 79 Hounsfield unit [HU]) of contrast medium within the tube in tube model. The models were scanned with two types of scan methods with a simulated ECG of 60 beats per minute and using display field of views (FOVs) of 9 and 18 cm. We evaluated the in-stent stenosis visually, and we measured the attenuation values and the diameter of the patent stent lumen. The visualization of the stent lumen of the vascular models was improved with using the prospective ECG-gated axial scans and a 9-cm FOV. The inner diameters of the vascular models were underestimated with mean measurement errors of -1.10 to -1.36 mm. The measurement errors were smaller with using the prospective ECG-gated axial scans (Bx-Velocity and Express2, p < 0.0001; Micro Driver, p = 0.0004) and a 9-cm FOV (all stents: p < 0.0001), as compared with the other conditions, respectively. The luminal attenuation value was overestimated in each condition. For the luminal attenuation measurement, the use of prospective ECG-gated axial scans provided less measurement error compared with the retrospective ECG-gated helical scans (all stents: p < 0.0001), and the use of a 9-cm FOV tended to decrease the measurement error. The visualization of coronary stents is improved by the use of prospective ECG-gated axial scans and using a small FOV with reduced blooming artifacts and increased spatial resolution

Strategy for optimal side-branch positioning of bioresorbable vascular scaffolds in dedicated 2-stent techniques: Insights from optical coherence tomography

International Nuclear Information System (INIS)

Miyazaki, Tadashi; Costopoulos, Charis; Sato, Katsumasa; Naganuma, Toru; Panoulas, Vasileios F.; Figini, Filippo; Latib, Azeem; Colombo, Antonio

2014-01-01

We present a case of a left anterior descending artery/diagonal branch bifurcation successfully treated with a dedicated 2-stent technique utilizing bioresorbable vascular scaffolds, where the bifurcation angle did not strictly allow a T-stenting approach. We also propose a strategy to avoid or reduce scaffold overlap in the main branch, especially important in view of the bulkier size of these novel devices

Effect of 125I seeds and 103Pd stents on proliferation of vascular smooth muscle cells

International Nuclear Information System (INIS)

Zhu Jun; Zhu Ruisen

2004-01-01

To establish the theoretical and practical base for implementing radioactive stents aft PTCA in order to prevent restenosis, in vitro observation was taken over the effects of 12 '5I-seeds and 103 Pd-implanted stents on the vascular smooth muscle cell (VSMC) proliferation. In vitro VSMC model from guinea-pig aortic arteries was established using adherent cell culture methods. The effects of 125 I-seeds and 103 Pd-implanted stents on the VSMC proliferation, with or without fetal bovine serum (FCS), were investigated through cell counting methods and 3 H-TDR implementation tests. It was shown that (1) 10% FCS significantly promoted the DNA synthesis of VSMC (P 125 I-seeds and 103 Pd-implanted stents inhibited the VSMC DNA synthesis in dose-dependent manner, regardless of 10% FCS inducement. At lower radioactive doses, neither 125 I-seeds (18.5-74 kBq) nor 103 Pd-implanted stents (1.48-2.96 MBq) exhibited distinctive effects on the VSMC DNA synthesis (P>0.05); and (3) 48 hour exposure from 125 I-seeds at 128 kBq or 10 '3Pd-implanted stents at 7.4 MBq did not result in VSMC morphological alteration, but 125 I-seeds at 370 kBq caused cells' morphological changes. Therefore both 125 I-seeds and 103 Pd-implanted stents inhibit the in vitro VSMC DNA synthesis, and the inhibition effects are significantly related to their exposure duration and doses. (authors)

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.

[Pulmonary reperfusion syndrome after pulmonary stent implants in a patient with vascular tortuosity syndrome].

Science.gov (United States)

Berenguer Potenciano, M; Piris Borregas, S; Mendoza Soto, A; Velasco Bayon, J M; Caro Barri, A

2015-01-01

Vascular tortuosity syndrome is a rare genetic disorder that causes tortuosity and stenosis of the pulmonary, systemic and / or coronary circulations. As a result of treatment of pulmonary stenosis, symptoms of pulmonary edema, known as lung reperfusion syndrome, may occur. The case is presented of an adolescent patient with vascular tortuosity syndrome who presented with a pulmonary reperfusion syndrome after multiple stent implants in the left pulmonary artery. After the procedure, the patient immediately developed an acute pulmonary edema with severe clinical deterioration, which required assistance with extracorporeal membrane oxygenation for recovery. Copyright © 2014 Asociación Española de Pediatría. Published by Elsevier Espana. All rights reserved.

Comparative vascular responses three months after paclitaxel and everolimus-eluting stent implantation in streptozotocin-induced diabetic porcine coronary arteries

Directory of Open Access Journals (Sweden)

Sheehy Alexander

2012-06-01

Full Text Available Abstract Background Diabetes remains a significant risk factor for restenosis/thrombosis following stenting. Although vascular healing responses following drug-eluting stent (DES treatment have been characterized previously in healthy animals, comparative assessments of different DES in a large animal model with isolated features of diabetes remains limited. We aimed to comparatively assess the vascular response to paclitaxel-eluting (PES and everolimus-eluting (EES stents in a porcine coronary model of streptozotocin (STZ-induced type I diabetes. Method Twelve Yucatan swine were induced hyperglycemic with a single STZ dose intravenously to ablate pancreatic β-cells. After two months, each animal received one XIENCE V® (EES and one Taxus Liberte (PES stent, respectively, in each coronary artery. After three months, vascular healing was assessed by angiography and histomorphometry. Comparative in vitro effects of everolimus and paclitaxel (10-5 M–10-12 M after 24 hours on carotid endothelial (EC and smooth muscle (SMC cell viability under hyperglycemic (42 mM conditions were assayed by ELISA. Caspase-3 fluorescent assay was used to quantify caspase-3 activity of EC treated with everolimus or paclitaxel (10-5 M, 10-7 M for 24 hours. Results After 3 months, EES reduced neointimal area (1.60 ± 0.41 mm, p vs. 0.08 ± 0.05, greater medial necrosis grade (0.52 ± 0.26 vs. 0.0 ± 0.0, and persistently elevated fibrin scores (1.60 ± 0.60 vs. 0.63 ± 0.41 with PES compared to EES (p In vitro, paclitaxel significantly increased (p -7 M, while everolimus did not affect EC/SMC apoptosis/necrosis within the dose range tested. In ECs, paclitaxel (10-5 M significantly increased caspase-3 activity (p  Conclusion After 3 months, both DES exhibited signs of delayed healing in a STZ-induced diabetic swine model. PES exhibited greater neointimal area, increased inflammation, greater medial necrosis, and

Relationship of serum S1P and HC-II levels with vasoactive substances and cytokines in patients with cerebral vascular restenosis after stent implantation

Directory of Open Access Journals (Sweden)

Yong Liu

2017-04-01

Full Text Available Objective: To study the relationship of serum sphingosine 1-phosphate (S1P and heparin cofactor II (HCII levels with vasoactive substances and cytokines in patients with cerebral vascular restenosis after stent implantation. Methods: 52 patients who received cerebrovascular stent implantation and developed restenosis in our hospital between May 2012 and December 2015 were collected as observation group, and 40 healthy patients with cerebrovascular stent implantation who had re-examination in our hospital during the same period were selected as control group. ELISA method was used to detect serum S1P and HC-II levels as well as vasoactive substance and inflammatory factor contents. Spearman correlation analysis was used to evaluate the relationship of serum S1P and HC-II levels with vasoactive substances and inflammatory factors. Results: Serum S1P and HC-II levels of observation group were lower than those of control group (P<0.05; serum vasoactive substances endothelin (ET, angiotensin II (AngII and thromboxane B2 (TXB2 contents of observation group were higher than those of control group while nitric oxide (NO content was lower than that of control group (P<0.05; serum inflammatory factors hypersensitive C-reactive protein (hs-CRP, interleukin-1 (IL-1, IL-6, IL-8 and IL-11 contents of observation group were higher than those of control group (P<0.05. Serum S1P and HC-II levels in patients with cerebral vascular restenosis after stent implantation were directly correlated with vasoactive substance and inflammatory factor contents. Conclusion: Serum S1P and HC-II levels decrease in patients with cerebral vascular restenosis after stent implantation, and it is an important cause of cerebral vascular dysfunction and systemic inflammatory response.

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

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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.

Drug-eluting or bare-metal stents for large coronary vessel stenting? The BASKET-PROVE (PROspective Validation Examination) trial: Study protocol and design

DEFF Research Database (Denmark)

Pfisterer, M.; Bertel, O.; Bonetti, P.O.

2008-01-01

or refute this hypothesis, we set up an 11-center 4-country prospective trial of 2260 consecutive patients treated with >= 3.0-mm stents only, randomized to receive Cypher (Johnson & Johnson, Miami Lakes, FL), Vision (Abbott Vascular, Abbott Laboratories, IL), or Xience stents (Abbott Vascular). Only...

Numerical investigations of the mechanical properties of braided vascular stents.

Science.gov (United States)

Fu, Wenyu; Xia, Qixiao; Yan, Ruobing; Qiao, Aike

2018-01-01

Braided stents, such as Pipeline Embolization Device (PED; ev3 Neurovascular, Irvine, CA, USA), are commonly used to treat cerebral aneurysms. However, little information is available on the compression and bending characteristics of such stents. This paper investigates how geometrical parameters of braided stents influence their radial compression and bending characteristics. Six groups of braided stent models with different braiding angles, numbers of wires and wire diameters are constructed. Parametric analyses of these models are conducted using Abaqus/Explicit software. The numerical results of a finite element analysis are validated by comparison with data of theoretical analysis. The results show that the radial stiffness is not uniform along the longitudinal direction of the stent. When the braiding angle increases from 30° to 75°, the minimum radial deformation decreases from 0.85 mm to 0.0325 mm (at a pressure of 500 Pa, for 24 braided wires). When the wire diameter increases from 0.026 mm to 0.052 mm, the minimum radial deformation decreases from 0.65 mm to 0.055 mm (at a pressure of 500 Pa and a braiding angle of 60°, for 24 braided wires). Frictions don't affect stent diameter and its axial length when braided stent is crimping, but the friction must be considered when it is related to the radial pressure required for compression the braided stent. Compared with commonly used intracranial stents, a braided stent with geometrical parameters close to PED stent has a smaller radial stiffness but a considerably greater longitudinal flexibility. The results of this analysis of braided stents can help in the design and selection of flow diverter stents for clinical treatment of cerebral aneurysms.

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...

Analysis of trends and prospects regarding stents for human blood vessels.

Science.gov (United States)

Lee, Jeong Hee; Kim, Eung Do; Jun, Eun Jung; Yoo, Hyoung Sun; Lee, Joon Woo

2018-01-01

The purpose of this paper is to provide technology trends and information regarding market and prospects in stents used for human blood vessels in Korea and the world.A stent is a medical device in the form of a cylindrical metal net used to normalize flow when blood or other bodily fluids such as biliary fluids are obstructed in blood vessels, gastrointestinal tracts, etc. by inserting the stent into a narrowed or clogged area. Stents are classified into vascular and non-vascular stents. The coronary artery stent is avascular stent that is used for coronary atherosclerosis.The demand is increasing for stents to treat diseases such as those affecting the heart and blood vessels of elderly and middle-aged patients. Due to the current shift in the demographic structure caused by an aging society, the prospect for stents seems to be very bright.The use of a stent designed to prevent acute vascular occlusion and restenosis, which is a side effect of conventional balloon angioplasty, has rapidly become popular because it can prevent acute complications and improve clinical outcomes. Since the initial release of this stent, there have been significant developments in its design, the most notable of which has been the introduction of drug-eluting stents (DES). Bioresorbable scaffolds (BRS) have the potential to introduce a paradigm shift in interventional cardiology, a true anatomical and functional "vascular restoration" instead of an artificial stiff tube encased by a persistent metallic foreign body. Data for this research were gathered from primary and secondary sources as well as the databases of the Korea Institute of Science Technology Information (KISTI) located in Seoul, Korea like KISTI Market Report. The sources used for primary research included the databases available from the Korea Institute of Science Technology Information, past industry research services/studies, economic and demographic data, and trade and industry journals. Secondary research was used

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.

Assessment of Vascular Stent Heating with Repetitive Transcranial Magnetic Stimulation.

Science.gov (United States)

Varnerin, Nicole; Mirando, David; Potter-Baker, Kelsey A; Cardenas, Jesus; Cunningham, David A; Sankarasubramanian, Vishwanath; Beall, Erik; Plow, Ela B

2017-05-01

A high proportion of patients with stroke do not qualify for repetitive transcranial magnetic stimulation (rTMS) clinical studies due to the presence of metallic stents. The ultimate concern is that any metal could become heated due to eddy currents. However, to date, no clinical safety data are available regarding the risk of metallic stents heating with rTMS. We tested the safety of common rTMS protocols (1 Hz and 10 Hz) with stents used commonly in stroke, nitinol and elgiloy. In our method, stents were tested in gelled saline at 2 different locations: at the center and at the lobe of the coil. In addition, at each location, stent heating was evaluated in 3 different orientations: parallel to the long axis of coil, parallel to the short axis of the coil, and perpendicular to the plane of the coil. We found that stents did not heat to more than 1°C with either 1 Hz rTMS or 10 Hz rTMS in any configuration or orientation. Heating in general was greater at the lobe when the stent was oriented perpendicularly. Our study represents a new method for ex vivo quantification of stent heating. We have found that heating of stents was well below the Food and Drug Administration standards of 2°C. Thus, our study paves the way for in vivo testing of rTMS (≤10 Hz) in the presence of implanted magnetic resonance imaging-compatible stents in animal studies. When planning human safety studies though, geometry, orientation, and location relative to the coil would be important to consider as well. Copyright © 2017 National Stroke Association. Published by Elsevier Inc. All rights reserved.

Interventional MRA: concepts for active visualization of catheters and stents

International Nuclear Information System (INIS)

Quick, H.H.; Ladd, M.E.

2003-01-01

A precondition to safe guidance of vascular guidewires and catheters during the course of magnetic resonance (MR)-guided vascular intervention is a high-contrast visualization of the instruments. The integration of miniature radiofrequency (RF) coils and coaxial cables into guidewires and catheters enables the reception of RF signal from the lumen of blood vessels, and thus the active visualization of the instruments. Moreover, metallic vascular implants (stents) can be modified to act as intravascular RF antennas that inductively couple their RF signal to a conventional surface RF coil. Such stent resonators show signal amplification inside the lumen of the stent and thus can be visualized with high contrast in MR images. Furthermore, once such a device has been implanted, the method offers the potential for non-invasive long-term follow-up of the stent patency. (orig.) [de

Stenting of the SFA - indications, techniques,

International Nuclear Information System (INIS)

Rieger, J.; Treitl, M.; Reiser, M.; Ruppert, V.

2006-01-01

Aggressive risk factor modification, change of eating habits, exercise programs, and forceful antiplatelet therapy are the most important tools for the treatment of PAOD in symptomatic patients suffering from intermittent claudication. There are however no guidelines for revascularization at this stage. Endovascular treatment has been increasingly utilized over the last decade and increasingly displaced vascular surgery. Amongst numerous endovascular techniques beside PTA, stents meanwhile play the most important role due to constant technical progress. Results regarding the rate of restenosis or patency rates still remain worse compared to other vascular beds. This paper gives a review over recent results, currently available stent techniques, and possible indications for the endovascular therapy of an artery, which has turned out to be the biggest ordeal for material and construction of stents. (orig.) [de

The application of DynaCT in performing the placement of intracranial stent

International Nuclear Information System (INIS)

Shen Hui; Wang Yongchun; Wang Minjie; Ding Hailing; Qin Yashan; Mao Yaqin; Li Songhua; Mao Yanjun; Hao Qiang

2011-01-01

Objective: To evaluate the clinical application of DynaCT technique in performing intracranial stent implantation. Methods: Thirty-nine patients who were planed to receive intracranial stent implantation were involved in this study. During the procedure DynaCT scanning was employed to monitor the real-time situation of stent implantation. Results: A total of 47 stents were implanted in intracranial vessels in the 39 patients. By using conventional angiography during operation the position of these stents was observed and was assured to be in the proper position. The adherence of these stents to the vascular wall was demonstrated with DynaCT multi-planar reconstruction images and the stent adherence in good condition was ensured. Conclusion: DynaCT applied during and after intracranial stent implantation is very helpful for displaying the contours of the stents as well as the vascular lumen and for providing a detail picture of the relationship between the stent and the surrounding anatomy. Therefore, DynaCT scanning is of great clinical significance for performing the intracranial stent implantation. (authors)

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

Vascular stents: Coupling full 3-D with reduced-order structural models

International Nuclear Information System (INIS)

Avdeev, I; Shams, M

2010-01-01

Self-expanding nitinol stents are used to treat peripheral arterial disease. The peripheral arteries are subjected to a combination of mechanical forces such as compression, torsion, bending, and contraction. Most commercially available peripheral self-expanding stents are composed of a series of sub-millimeter V-shaped struts, which are laser-cut from a nitinol tube and surface-treated for better fatigue performance. The numerical stent models must accurately predict location and distribution of local stresses and strains caused by large arterial deformations. Full 3-D finite element non-linear analysis of an entire stent is computationally expensive to the point of being prohibitive, especially for longer stents. Reduced-order models based on beam or shell elements are fairly accurate in capturing global deformations, but are not very helpful in predicting stent failure. We propose a mixed approach that combines the full 3-D model and reduced-order models. Several global-local, full 3-D/reduced-order finite element models of a peripheral self-expanding stent were validated and compared with experimental data. The kinematic constraint method used to couple various elements together was found to be very efficient and easily applicable to commercial FEA codes. The proposed mixed models can be used to accurately predict stent failure based on realistic (patient-specific), non-linear kinematic behavior of peripheral arteries.

Basic Knowledge about Metal Stent Development

Directory of Open Access Journals (Sweden)

Seok Jeong

2016-03-01

Full Text Available Biliary self-expandable metal stents (SEMS, a group of non-vascular stents, have been used in the palliative management of biliary obstruction around the world. However, there are still unmet needs in the clinical application of biliary SEMS. Comprehensive understanding of the SEMS is required to resolve the drawbacks and difficulties of metal stent development. The basic structure of SEMS, including the materials and knitting methods of metal wires, covering materials, and radiopaque markers, are discussed in this review. What we know about the physical and mechanical properties of the SEMS is very important. With an understanding of the basic knowledge of metal stents, hurdles such as stent occlusion, migration, and kinking can be overcome to develop more ideal SEMS.

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

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

Technological Advances in Stent Therapies: a Year in Review.

Science.gov (United States)

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

2018-04-07

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

Luminal flow amplifies stent-based drug deposition in arterial bifurcations.

Directory of Open Access Journals (Sweden)

Vijaya B Kolachalama

2009-12-01

Full Text Available Treatment of arterial bifurcation lesions using drug-eluting stents (DES is now common clinical practice and yet the mechanisms governing drug distribution in these complex morphologies are incompletely understood. It is still not evident how to efficiently determine the efficacy of local drug delivery and quantify zones of excessive drug that are harbingers of vascular toxicity and thrombosis, and areas of depletion that are associated with tissue overgrowth and luminal re-narrowing.We constructed two-phase computational models of stent-deployed arterial bifurcations simulating blood flow and drug transport to investigate the factors modulating drug distribution when the main-branch (MB was treated using a DES. Simulations predicted extensive flow-mediated drug delivery in bifurcated vascular beds where the drug distribution patterns are heterogeneous and sensitive to relative stent position and luminal flow. A single DES in the MB coupled with large retrograde luminal flow on the lateral wall of the side-branch (SB can provide drug deposition on the SB lumen-wall interface, except when the MB stent is downstream of the SB flow divider. In an even more dramatic fashion, the presence of the SB affects drug distribution in the stented MB. Here fluid mechanic effects play an even greater role than in the SB especially when the DES is across and downstream to the flow divider and in a manner dependent upon the Reynolds number.The flow effects on drug deposition and subsequent uptake from endovascular DES are amplified in bifurcation lesions. When only one branch is stented, a complex interplay occurs - drug deposition in the stented MB is altered by the flow divider imposed by the SB and in the SB by the presence of a DES in the MB. The use of DES in arterial bifurcations requires a complex calculus that balances vascular and stent geometry as well as luminal flow.

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.

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 study of metal stents for effect to the radiation therapy

International Nuclear Information System (INIS)

Gao Li; Feng Ningyuan; Zhai Renyou; Yang Weizhi; Xu Guozhen; Wang Yafei

2001-01-01

Objective: To confirm whether the metal stents affect the radiation beam. Methods: The transmission factors from the national self-expanding esophagus stent, stainless self-expanding bile duct stent, and balloon-expanded vascular stent was supervised under 192 Ir irradiation in the air. Results: The transmission factors from the 3 kinds of metal stents were 0.993, 0.988, and 0.997, which meant that the attenuation of the stents to the radiation was 0.7%, 1.2%, and 0.3%, respectively (mean: 0.7%). Conclusion: The effect of the metal stents to the radiation was less than 1.2% and that meant there was no clinical significant effect on the patients irradiated following stent implantation or to perform the intra-stents brachytherapy

Self-Expandable Stenting over a Stent Graft for the Exclusion of a Carotid Stump: Troubleshooting for Device Incompatibility

International Nuclear Information System (INIS)

Youn, Sung Won; Kim, Ho Kyun; Do, Jin Kook; Kim, Young Whan

2011-01-01

Carotid stump, the blind remnant of an occluded internal carotid artery, can be a potential source of microemboli, and warrants its exclusion from the vascular lumen to prevent the recurrence of a microembolism. In a 69-year-old male with a symptomatic carotid stump and acute angle between left common carotid artery and aortic arch, a 7-Fr. shuttle sheath was scarcely placed into the left carotid artery but the 7-mm-diameter stent-graft-loading balloon could not be inserted into the 7-Fr. shuttle sheath. With the mounting a stent graft over a 5-mm balloon, the balloon-expandable stent graft was unfolded. The self-expandable stent was placed over the stent graft, and an 8-mm balloon was subsequently expanded. Self-expanding stenting can be useful for troubleshooting in a case of device incompatibility coming from the different calibers of the external and common carotid arteries for the successful exclusion of a symptomatic carotid stump.

Self-Expandable Stenting over a Stent Graft for the Exclusion of a Carotid Stump: Troubleshooting for Device Incompatibility

Energy Technology Data Exchange (ETDEWEB)

Youn, Sung Won; Kim, Ho Kyun [Dept. of Radiology, Catholic University of Daegu School of Medicine, Daegu (Korea, Republic of); Do, Jin Kook [Dept. of Neurology, Catholic University of Daegu School of Medicine, Daegu (Korea, Republic of); Kim, Young Whan [Dept. of Radiology, University College of Medicine, Daegu (Korea, Republic of)

2011-12-15

Carotid stump, the blind remnant of an occluded internal carotid artery, can be a potential source of microemboli, and warrants its exclusion from the vascular lumen to prevent the recurrence of a microembolism. In a 69-year-old male with a symptomatic carotid stump and acute angle between left common carotid artery and aortic arch, a 7-Fr. shuttle sheath was scarcely placed into the left carotid artery but the 7-mm-diameter stent-graft-loading balloon could not be inserted into the 7-Fr. shuttle sheath. With the mounting a stent graft over a 5-mm balloon, the balloon-expandable stent graft was unfolded. The self-expandable stent was placed over the stent graft, and an 8-mm balloon was subsequently expanded. Self-expanding stenting can be useful for troubleshooting in a case of device incompatibility coming from the different calibers of the external and common carotid arteries for the successful exclusion of a symptomatic carotid stump.

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.

An automatic algorithm for detecting stent endothelialization from volumetric optical coherence tomography datasets

Energy Technology Data Exchange (ETDEWEB)

Bonnema, Garret T; Barton, Jennifer K [College of Optical Sciences, University of Arizona, Tucson, AZ (United States); Cardinal, Kristen O' Halloran [Biomedical and General Engineering, California Polytechnic State University (United States); Williams, Stuart K [Cardiovascular Innovation Institute, University of Louisville, Louisville, KY 40292 (United States)], E-mail: barton@u.arizona.edu

2008-06-21

Recent research has suggested that endothelialization of vascular stents is crucial to reducing the risk of late stent thrombosis. With a resolution of approximately 10 {mu}m, optical coherence tomography (OCT) may be an appropriate imaging modality for visualizing the vascular response to a stent and measuring the percentage of struts covered with an anti-thrombogenic cellular lining. We developed an image analysis program to locate covered and uncovered stent struts in OCT images of tissue-engineered blood vessels. The struts were found by exploiting the highly reflective and shadowing characteristics of the metallic stent material. Coverage was evaluated by comparing the luminal surface with the depth of the strut reflection. Strut coverage calculations were compared to manual assessment of OCT images and epi-fluorescence analysis of the stented grafts. Based on the manual assessment, the strut identification algorithm operated with a sensitivity of 93% and a specificity of 99%. The strut coverage algorithm was 81% sensitive and 96% specific. The present study indicates that the program can automatically determine percent cellular coverage from volumetric OCT datasets of blood vessel mimics. The program could potentially be extended to assessments of stent endothelialization in native stented arteries.

Biodegradable, elastomeric coatings with controlled anti-proliferative agent release for magnesium-based cardiovascular stents.

Science.gov (United States)

Gu, Xinzhu; Mao, Zhongwei; Ye, Sang-Ho; Koo, Youngmi; Yun, Yeoheung; Tiasha, Tarannum R; Shanov, Vesselin; Wagner, William R

2016-08-01

Vascular stent design continues to evolve to further improve the efficacy and minimize the risks associated with these devices. Drug-eluting coatings have been widely adopted and, more recently, biodegradable stents have been the focus of extensive evaluation. In this report, biodegradable elastomeric polyurethanes were synthesized and applied as drug-eluting coatings for a relatively new class of degradable vascular stents based on Mg. The dynamic degradation behavior, hemocompatibility and drug release were investigated for poly(carbonate urethane) urea (PCUU) and poly(ester urethane) urea (PEUU) coated magnesium alloy (AZ31) stents. Poly(lactic-co-glycolic acid) (PLGA) coated and bare stents were employed as control groups. The PCUU coating effectively slowed the Mg alloy corrosion in dynamic degradation testing compared to PEUU-coated, PLGA-coated and bare Mg alloy stents. This was confirmed by electron microscopy, energy-dispersive x-ray spectroscopy and magnesium ion release experiments. PCUU-coating of AZ31 was also associated with significantly reduced platelet adhesion in acute blood contact testing. Rat vascular smooth muscle cell (rSMC) proliferation was successfully inhibited when paclitaxel was released from pre-loaded PCUU coatings. The corrosion retardation, low thrombogenicity, drug loading capacity, and high elasticity make PCUU an attractive option for drug eluting coating on biodegradable metallic cardiovascular stents. Copyright © 2016 Elsevier B.V. All rights reserved.

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

Science.gov (United States)

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

2015-08-01

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

Overtime evaluation of the vascular HEALing process after everolimus-eluting stent implantation by optical coherence tomography. The HEAL-EES study

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Otsuki, Shuji; Brugaletta, Salvatore, E-mail: sabrugal@clinic.ub.es; Sabaté, Manel; Shiratori, Yoshitaka; Gomez-Monterrosas, Omar; Scalone, Giancarla; Romero-Villafañe, Sebastian; Hernández-Enríquez, Marco; Freixa, Xavier; Martín-Yuste, Victoria; Masotti, Mónica

2016-06-15

Purpose: Second-generation drug-eluting stent (DES) have shown a better safety and efficacy as compared to first generation DES due to an improved vascular healing process. This process has not been so far evaluated in vivo in an overtime fashion by optical coherent tomography (OCT). We sought to evaluate the vascular healing process after everolimus-eluting stent (EES) implantation at 6, 9 and 12 months, by OCT. Methods: Consecutive 36 patients undergoing percutaneous coronary intervention with EES were randomized 1:1:1 to receive OCT imaging at 6 (group A), 9 (group B) or 12-month follow-up (group C). One patient from group C was excluded because of target lesion revascularization at 1-month, whereas 5 patients withdraw the informed consent. Finally, 30 patients were analyzed. Results: Neointimal thickness was not different between 3 groups (group A: 99.50 [94.06–127.79] μm, group B: 107.26 [83.48–133.59] μm, group C: 127.67 [102.51–138.49] μm; p = 0.736). Although the percentage of “uncovered struts” was significantly higher in group A as compared to the other groups (8.0% vs. 4.4% vs. 2.9%, respectively; p = 0.180), the ratio of uncovered to total struts per section < 30% was similar between 3 groups (0.3% vs. 0.3% vs. 0%, respectively; p = 1.000). Conclusion: Healing process following EES implantation seems almost completed at 6-month follow-up. These data, which need to be confirmed in a larger study, may support the decision to shorten dual antiplatelet therapy. - Highlights: • Healing process following everolimus-eluting stent implantation is complete at 6-month • There are no difference in RUTTS > 30% between 6, 9 and 12 months analyses. • This finding may support to shorten dual antiplatelet therapy in this context.

Stent-assisted mechanical recanalization for the treatment of acute ischemic stroke

International Nuclear Information System (INIS)

Xu Haowen; Song Bo; Guo Xinbin; Guan Sheng

2011-01-01

Objective: to evaluate the safety and efficacy of stent-assisted mechanical recanalization technique in treating acute ischemic stroke. Methods: Stent-assisted mechanical recanalization procedure was carried out in 12 patients with acute ischemic stroke. The lesions were located at the anterior circulation in 10 cases and at posterior circulation in 2 cases. The clinical data were retrospectively analyzed. The technical success rate, the vascular recanalization, the occurrence of symptomatic intracranial hemorrhage, the clinical improvement and mortality were observed and evaluated. Results: The stent was successfully deployed in 11 patients (92%). After the treatment, different degrees of vascular recanalization were obtained in all patients. The complete (TIMI 3), partial (TIMI 2) and minor (TIMI 1) recanalization rate was 58.3% (7/12), 25% (3/12) and 8.3% (1/12), respectively. Postoperative symptomatic intracranial hemorrhage occurred in one patient (8.3%). Stroke-related death occurred in one patient (8.3%) and eight patients had their modified Rankin Score ≤ 2. Conclusion: For the treatment of acute ischemic stroke, stent-assisted mechanical recanalization technique is clinically feasible and safe with high vascular recanalization rate although further studies with larger sample to clarify its clinical usefulness are still needed. (authors)

Factors Associated with In-stent Restenosis in Patients Following Percutaneous Coronary Intervention

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Dedi Wihanda

2015-07-01

Full Text Available Aim: to determine factors associated with In-Stent Restenosis (ISR in patients following Percutaneous Coronary Intervention (PCI. Methods: a retrospective cross-sectional study was conducted using secondary information from medical records of post-PCI patients who underwent follow-up of angiography PCI between January 2009 and March 2014 at The Integrated Cardiovascular Service Unit, Cipto Mangunkusumo Hospital, Jakarta. Angiographic ISR was defined when the diameter of stenosis ≥50% at follow-up angiography including the diameter inside the stent and diameter with five-mm protrusion out of the proximal and distal ends of the stent. Results: there were 289 subjects including 133 subjects with and 156 subjects without ISR. The incidence of ISR in patients using of bare-metal stent (BMS and drug-eluting stent (DES were 61.3% and 40.7%, respectively. Factors associated with ISR are stent-type (OR=4.83, 95% CI 2.51-9.30, stent length (OR=3.71, 95% CI 1.99-6.90, bifurcation lesions (OR=2.43, 95% CI 1.16-5.10, smoking (OR=2.30, 95% CI 1.33-3.99, vascular diameter (OR=2.18, 95% CI 1.2-3.73, hypertension (OR=2.16, 95% CI 1.16-4.04 and diabetes mellitus (OR=2.14, 95% CI 1.23-3.70. Conclusion: stent type, stent length, bifurcation lesions, smoking, vascular diameter, hypertension and DM are factors associated with ISR in patients following PCI. Key words: bare-metal stent; drug-eluting stent; in-stent restenosis.

An experimental study on expandable endovascular metallic stents in dogs

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Song, Ho Young; Kim, Hak Nam [Chonbuk National University College of Medicine, Chonju (Korea, Republic of)

1990-12-15

We constructed an expandable endovascular metallic stent in the same way as Giamturco did. Experiments were made to test the ability of these stents to be used in the vessels. A total of 20 stents were passed through a 8.5 French teflon sheath into the normal abdominal aorta. IVC, and iliac artery of four adult dogs for 4 weeks to 12 weeks; 8 stents (10 mm in diameter fully expanded and 20 mm in length) in the abnormal aorta, 7 stents (12 mm/20 mm) in the IVC, and 5 stents (8 mm/20 mm) in the iliac artery. All but two stents showed no migration, and one complete occlusion occurred in right iliac artery of a dog. Histologically, stents wires were covered by neo-intimal proliferation. The side branches of the main vessels remained patent, even stent wires across their orifices. These metallic stents may be used as an endovascular graft material in the nonsurgical treatment of several forms of vascular disease.

OrbusNeich fully absorbable coronary stent platform incorporating dual partitioned coatings.

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Cottone, Robert J; Thatcher, G Lawrence; Parker, Sherry P; Hanks, Laurence; Kujawa, David A; Rowland, Stephen M; Costa, Marco; Schwartz, Robert S; Onuma, Yoshinobu

2009-12-15

The field of stent based tissue engineering continues to revolutionise modern medicine by designing novel materials to restore vascular tissue function. Accordingly, the following discussion examines a novel, absorbable, polymeric scaffold engineered in combination with dual therapeutic coating, enabling locally administered temporary scaffolding in the coronary arteries for long term vascular patency and repair. This coronary stent platform consists of an absorbable polymeric material stent structure that incorporates a dual partitioned coating, by means of pro-healing EPC (endothelial progenitor cell) capture technology allowing for rapid endothelial coverage, and an absorbable polymer matrix with sustained elution of sirolimus, a drug controlling neointimal proliferation. This paper provides a brief overview of the various innovations developed by OrbusNeich to create this fully absorbable coronary device platform.

Computational micromechanics of bioabsorbable magnesium stents.

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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.

Drug-eluting stent implantation for the percutaneous treatment of vertebro-basilar arterial stenosis

International Nuclear Information System (INIS)

Ma Rujun; Liu Jianmin; Huang Haiqing; Hong Bo; Xu Yi; Zhao Wenyuan; Zhao Rui; Chen Jun

2006-01-01

Objective: To evaluate the early results and mid-term outcomes following angioplasty of vertebro-basilar arterial stenosis with drug-eluting stents. Methods: All of the patients presented with recurrent TIA or ceretral infarction with >50% stenoses in vertebro-basilar arteries, and having failure in maximal medical therapy. All of the lesions were treated with primary stenting under local or general anesthesia and followed by continual anticoagulant therapy of clopidogrel and aspirin together with clinical follow-up and vascular imagings. Results: Of 28 stenoses (27 patients), 27 lesions were successfully treated with implantation of 24 Cypher stents, 2 Taxus stents and one Firebird stent. The mean stenotic severity reduced from (74 ± 6.7)% to (8.7 ± 4.4)%. Two patients had inchemic events relating to penetration vascular obstruction. During 2-14 months follow-up, the patients were clinically asymptomatic with no recurrent TIA/stoke. Angiographic follow-up was obtained in 14 patients at a mean of 7.2 months. Proximal restenosis (<50%) occurred in one patient (3.3%), and corrected with restenting, while others were free of intra-stent restenoses. Conclusion: Using DES in cerebrovascular stenosis is safe and effective with lowing the risk of intra-stent restenosis in comparison with bare stent. Further study for long term efficiency is still in need. (authors)

Square Stent: A New Self-Expandable Endoluminal Device and Its Applications

International Nuclear Information System (INIS)

Pavcnik, Dusan; Uchida, Barry; Timmermans, Hans; Keller, Frederick S.; Roesch, Josef

2001-01-01

The square stent is a new, simply constructed, self-expanding device that has recently been described. Compared with other stents, the square stent has a minimal amount of metal and thus requires a smaller-diameter catheter for introduction. Despite the small amount of metal present, the square stent has adequate expansile force. We have been evaluating the square stent for various interventional applications. In addition to the basic square stent, combinations of square stents and coverings for square stents were developed and evaluated to expand its uses and indications. One of the coverings tested is a new biomaterial: small intestinal submucosa (SIS). This paper will discuss the various applications of the square stent, which include a retrievable inferior vena cava filter, vascular occluder, graft adapter, and venous and aortic valves. In addition, we will review the important properties of SIS as a covering for the square stent

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

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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.

A review on biodegradable materials for cardiovascular stent application

Science.gov (United States)

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

2016-09-01

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

Investigation Of Interaction Between Nitinol Stent And A Vascular Plaque Using Finite Element Method

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Recep Güneş

2012-06-01

Full Text Available In this study, the interaction between the Nitinol stent and the artery with plaque was investigated using finite element method. The occurring pressure values during the cardiac contraction (systolic and loosening (diastolic were applied as loading to the modeled system with Nitinol stent. In the light of the stress values, the suitability of the Nitinol stent in an artery with plaque was investigated. In the analysis, Nitinol stent was assumed to be shape memory alloy, and artery and plaque were assumed to behave linearly elastic. As a result, the stress and deformations in the plaque and artery due to the interference of Nitinol stent were discussed and concluded that the structure of artery with plaque can be expanded in accordance with Nitinol stent.

Why Vascular Surgeons and Interventional Radiologists Collaborate or Compete: A Look at Endovascular Stent Placements

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Keller, Eric J.; Collins, Jeremy D. [Northwestern University Feinberg School of Medicine, Department of Radiology (United States); Crowley-Matoka, Megan [Northwestern University Feinberg School of Medicine, Center for Bioethics and Medical Humanities (United States); Chrisman, Howard B. [Northwestern University Feinberg School of Medicine, Department of Radiology (United States); Milad, Magdy P. [Northwestern University Feinberg School of Medicine, Department of Obstetrics and Gynecology-Reproductive Endocrinology and Infertility (United States); Vogelzang, Robert L., E-mail: vogelzang@northwestern.edu [Northwestern University Feinberg School of Medicine, Department of Radiology (United States)

2017-06-15

PurposeTo understand how cultural differences between vascular surgeons (VSs) and interventional radiologists (IRs) affect their clinical decision making and inter-specialty relationships.MethodsTwenty-four conversational interviews were conducted with IRs and VSs about their approaches to patient care, views of their specialty and others, and solutions to any expressed concerns. Interview transcripts were systematically analyzed to identify and compare key themes according to the constructivist grounded theory and content analysis using NVivo 10 software. These data were supplemented with a retrospective analysis of 3658 endovascular stent placements performed at a large medical academic center over 11 years. Aggregate counts were divided by provider specialty, and trends were assessed via correlation coefficients.ResultsEndovascular stent placements were relatively equally divided between IR and VS over 11 years with some variability from placements by cardiology. IRs tend to lay claim to treatments as masters of procedures, whereas VSs base their claims on being masters of the treated diseases, leading to collaboration in some practices and bitter competition in others. The level of perceived competition was most associated with specialists’ awareness of and appreciation for specialty-specific values rather than differences in practice structure/reimbursement.ConclusionsUnderstanding cultural differences between IRs and VSs is imperative for fostering better collaboration to grow shared territory rather than competing for the same slice of the pie.

Why Vascular Surgeons and Interventional Radiologists Collaborate or Compete: A Look at Endovascular Stent Placements

International Nuclear Information System (INIS)

Keller, Eric J.; Collins, Jeremy D.; Crowley-Matoka, Megan; Chrisman, Howard B.; Milad, Magdy P.; Vogelzang, Robert L.

2017-01-01

PurposeTo understand how cultural differences between vascular surgeons (VSs) and interventional radiologists (IRs) affect their clinical decision making and inter-specialty relationships.MethodsTwenty-four conversational interviews were conducted with IRs and VSs about their approaches to patient care, views of their specialty and others, and solutions to any expressed concerns. Interview transcripts were systematically analyzed to identify and compare key themes according to the constructivist grounded theory and content analysis using NVivo 10 software. These data were supplemented with a retrospective analysis of 3658 endovascular stent placements performed at a large medical academic center over 11 years. Aggregate counts were divided by provider specialty, and trends were assessed via correlation coefficients.ResultsEndovascular stent placements were relatively equally divided between IR and VS over 11 years with some variability from placements by cardiology. IRs tend to lay claim to treatments as masters of procedures, whereas VSs base their claims on being masters of the treated diseases, leading to collaboration in some practices and bitter competition in others. The level of perceived competition was most associated with specialists’ awareness of and appreciation for specialty-specific values rather than differences in practice structure/reimbursement.ConclusionsUnderstanding cultural differences between IRs and VSs is imperative for fostering better collaboration to grow shared territory rather than competing for the same slice of the pie.

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.

Efectos biológicos de los stents medicados en la circulación coronaria Biological effects of drug-eluting stents in the coronary circulation

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Darío Echeverri

2010-04-01

Full Text Available Los stents medicados ofrecen la mejor alternativa disponible no quirúrgica para el tratamiento de la enfermedad coronaria gracias a su demostrada eficacia. Sin embargo, estos excelentes resultados han sido opacados en términos de seguridad, principalmente por la presencia de trombosis de stents de manera tardía o muy tardía. La comprensión de los efectos biológicos que ejercen a nivel de la arteria coronaria luego de su implante, se debe al efecto de la plataforma utilizada, el polímero y la droga que liberan. Los trastornos de reparación vascular inducidos favorecen la trombosis de stents y sus consecuencias clínicas. Se hace una revisión de los diferentes efectos biológicos de los stents medicados en las arterias coronarias, que permite comprender como han surgido rápidamente nuevas versiones en materiales, diseños, polímeros y medicamentos que reducen los efectos adversos a nivel coronario, mejorando su eficacia y seguridad.Drug-eluting stents offer the best available non-surgical alternative for the treatment of coronary disease, thanks to its demonstrated efficacy. However, in terms of security, these excellent results have been overshadowed by the late or very late appearance of stent thromboses.The biological effects they have in the coronary artery after its implantation are due to the effect of the platform used, the polymer and the medication released. The vascular healing disorders induced by drug-eluting stents favor stent thrombosis and its clinical consequences. This is a review of the different biological effects of drug-eluting stents in coronary arteries that allows to understand how the rapid onset of new versions of materials, designs, polymers and medications diminish adverse coronary effects and improve its efficacy and safety.

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.

Magnetizable stent-grafts enable endothelial cell capture

Energy Technology Data Exchange (ETDEWEB)

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. �

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

Science.gov (United States)

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

2018-01-01

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

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

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.

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

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)

French experience of silicone tracheobronchial stenting in children.

Science.gov (United States)

Fayon, Michael; Donato, Lionel; de Blic, Jacques; Labbé, André; Becmeur, François; Mely, Laurent; Dutau, Hervé

2005-01-01

Silicone stents were inserted into the trachea or left main-stem bronchus in 14 children aged 2-69 months (median, 7 months). Indications were as follows: tracheomalacia or airway kinking (7 cases), vascular compression (5 cases), and surgically corrected congenital tracheal stenoses (2 cases). The best results were obtained in tracheomalacia. Overall, 6 cases out of 14 (43%) were considered successful, with a stent placement duration of 3-15 months (median, 7 months). Two cases were considered a technical success, although they were clinical failures. Five cases were considered failures primarily due to stent migration. A retrospective analysis of failures suggests that most of these could have been avoided by the use of larger stents. One patient died of stent obstruction. No wall erosion was observed, and the development of granulation tissue was infrequent. Endoscopic removal of the prostheses was uneventful. The biocompatibility of silicone stents appears to be better than what is reported for metal ones, although the stability of the former is less satisfactory. The present study shows the feasibility of silicone stent placement in infants. These stents should be considered as a possible therapeutic option in certain types of childhood airway disorders, although further studies are required.

Vascular Biocompatibility of a Triple Layered Self Expanding Stent-Graft in a Dog Mode

Energy Technology Data Exchange (ETDEWEB)

Bae, Jae Ik; Won, Je Hwan; Jang, Eun Ho; Lee, Sung Yeong; Ko, Kwang Tae [Dept. of Radiology, Ajou University School of Medicine, Suwon (Korea, Republic of); Jin, Bo Hwan [Medical Science Research Center, Ajou University School of Medicine, Suwon (Korea, Republic of); Lee, June Woo [Dept. of Radiology, Busan National University College of Medicine, Busan (Korea, Republic of)

2012-02-15

To evaluate performance and biocompatibility of a newly designed self-expanding stent graft, which consisted of two nitinol stents and an intervening expanded polytetrafluoroethylene membrane in a dog artery model. Twelve stent grafts were placed in the aorta of 6 dogs (beagle, mean body weight 11 kg) for 4 weeks (n = 4) and 12 weeks (n = 8). Luminal diameters were measured for each segment (the proximal bare, the middle graft, the distal bare) by angiographies after implantation and follow up periods. Percent luminal stenosis based on angiographies, histomorphometric, histologic, and scanning electron microscopic analyses of each segments were performed. Blood flow through the stent grafts was good after implantation and during the follow up period, without thrombotic occlusion or stent graft migration. The mean percent luminal stenosis of the proximal bare, the middle grafted and the distal bare segments after 12 weeks were 13.5%, 3.9%, 9.6% retrospectively. The mean neointimal areas of the middle grafted segment were 4.39 mm{sup 2} (4 week) and 4.92 mm{sup 2} (12 week). Mature endothelialization was evident in over 70% of the area of the stented artery after 4 weeks and in over 90% after 12 weeks. The stent graft was well placed in the attempted area without migration. During the 12-week-follow up period, it showed a good patency without thrombotic occlusion or significant in-stent luminal stenosis. Endothelialization was rapid and nearly complete. Neointima was thin and smooth on the middle graft segment and thicker and irregular on the bare segments.

Vascular Biocompatibility of a Triple Layered Self Expanding Stent-Graft in a Dog Mode

International Nuclear Information System (INIS)

Bae, Jae Ik; Won, Je Hwan; Jang, Eun Ho; Lee, Sung Yeong; Ko, Kwang Tae; Jin, Bo Hwan; Lee, June Woo

2012-01-01

To evaluate performance and biocompatibility of a newly designed self-expanding stent graft, which consisted of two nitinol stents and an intervening expanded polytetrafluoroethylene membrane in a dog artery model. Twelve stent grafts were placed in the aorta of 6 dogs (beagle, mean body weight 11 kg) for 4 weeks (n = 4) and 12 weeks (n = 8). Luminal diameters were measured for each segment (the proximal bare, the middle graft, the distal bare) by angiographies after implantation and follow up periods. Percent luminal stenosis based on angiographies, histomorphometric, histologic, and scanning electron microscopic analyses of each segments were performed. Blood flow through the stent grafts was good after implantation and during the follow up period, without thrombotic occlusion or stent graft migration. The mean percent luminal stenosis of the proximal bare, the middle grafted and the distal bare segments after 12 weeks were 13.5%, 3.9%, 9.6% retrospectively. The mean neointimal areas of the middle grafted segment were 4.39 mm 2 (4 week) and 4.92 mm 2 (12 week). Mature endothelialization was evident in over 70% of the area of the stented artery after 4 weeks and in over 90% after 12 weeks. The stent graft was well placed in the attempted area without migration. During the 12-week-follow up period, it showed a good patency without thrombotic occlusion or significant in-stent luminal stenosis. Endothelialization was rapid and nearly complete. Neointima was thin and smooth on the middle graft segment and thicker and irregular on the bare segments.

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

.25% of retrograde stents having any complication. Parallel stent grafting offers an off-the-shelf option to treat a variety of aortic diseases. There is an increased risk of parallel stent and overall EVAR compromise with stent is placed. Antegrade configurations are preferred to any retrograde configuration, with optimal oversizing >20%. Copyright © 2017 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

Modificações na angulação coronária após implante de suporte vascular bioabsorvível e de stents de cromo-cobalto e aço inoxidável

OpenAIRE

Silva, Mateus Veloso e; Costa Jr., J. Ribamar; Abizaid, Alexandre; Staico, Rodolfo; Taiguara, Danillo; Borghi Jr., Tarcísio Campostrini; Costa, Ricardo; Chamié, Daniel; Sousa, Amanda G. M. R.; Sousa, J. Eduardo

2013-01-01

INTRODUÇÃO: A conformabilidade do stent, definida como a adaptação da prótese à forma natural do vaso, é a principal responsável pelas alterações geométricas produzidas após o implante do dispositivo, sendo influenciada pelo material e pelo desenho do stent. Ela pode ser aferida medindo-se as modificações da curvatura e a angulação do segmento tratado após o implante do stent. O objetivo deste estudo foi comparar as mudanças na angulação coronária após implante do suporte vascular bioabsorvív...

Flow-induced corrosion behavior of absorbable magnesium-based stents.

Science.gov (United States)

Wang, Juan; Giridharan, Venkataraman; Shanov, Vesselin; Xu, Zhigang; Collins, Boyce; White, Leon; Jang, Yongseok; Sankar, Jagannathan; Huang, Nan; Yun, Yeoheung

2014-12-01

The aim of this work was to study corrosion behavior of magnesium (Mg) alloys (MgZnCa plates and AZ31 stents) under varied fluid flow conditions representative of the vascular environment. Experiments revealed that fluid hydrodynamics, fluid flow velocity and shear stress play essential roles in the corrosion behavior of absorbable magnesium-based stent devices. Flow-induced shear stress (FISS) accelerates the overall corrosion (including localized, uniform, pitting and erosion corrosions) due to the increased mass transfer and mechanical force. FISS increased the average uniform corrosion rate, the localized corrosion coverage ratios and depths and the removal rate of corrosion products inside the corrosion pits. For MgZnCa plates, an increase of FISS results in an increased pitting factor but saturates at an FISS of ∼0.15Pa. For AZ31 stents, the volume loss ratio (31%) at 0.056Pa was nearly twice that (17%) at 0Pa before and after corrosion. Flow direction has a significant impact on corrosion behavior as more severe pitting and erosion corrosion was observed on the back ends of the MgZnCa plates, and the corrosion product layer facing the flow direction peeled off from the AZ31 stent struts. This study demonstrates that flow-induced corrosion needs be understood so that Mg-based stents in vascular environments can be effectively designed. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Evaluation of Silicone as an Endovascular Stent Membrane: In Vivo Canine Studies

International Nuclear Information System (INIS)

Fontaine, Arthur B.; Borsa, John J.; Hoffer, Eric; Bloch, Robert; So, Corali

2001-01-01

Purpose: Comparative evaluation of the biological effects of a silicone-covered stent versus a bare-metal stent, in an animal model.Methods: Twelve stent implants were placed in the iliac arteries of six adult dogs. Each animal received one 8-mm x 20-mm silicone-covered stent (Permalume; Boston Scientific Vascular, Watertown, MA, USA), in the right iliac artery and one Wallstent (Boston Scientific Vascular) of the same diameter and length in the left iliac artery, during systemic anticoagulation. Angiography was performed before and after implantations. Animals were then allowed to recover and no platelet suppression was given during a 6-week interval, after which the animals were euthanized. The stented arteries were isolated and pressure-fixed in situ with 10% buffered formalin at a pressure of approximately 100 mmHg for a period of 1 hr. Two of 12 stented specimens were opened lengthwise and the luminal surfaces were photographed. Ten of 12 stented arterial segments were encased in methacrylate, then stained with hematoxylin and eosin. Neointimal thickness was quantified on histologic cross-section, for both bare and covered stents. The mean neointimal thicknesses were compared for significant difference using a student t-test.Results: All implants were widely patent at 6-week follow-up angiography. Histologic analysis showed bare metal stents covered by a thin uniform lining of neointima composed of smooth muscle cells in a hyaline matrix (mean thickness of 189 ± 47 μm). Silicone covered stents were devoid of neointima. There was no chronic thrombus or mature endothelium noted anywhere upon the internal silicone surfaces of any of the specimens. There was no foreign body reaction to the silicone cover.Conclusion: Short-term implantation of a silicone-lined Wallstent in canine iliac arteries is well tolerated. Silicone appears to be inert at 6 weeks in this experimental application

Usefulness of CT angiography after metallic stent implantation of the internal carotid artery

International Nuclear Information System (INIS)

Yoon, Man Won; Kim, Hyeon Chul; Kim, Jae Kyu; Seo, Jeong Jin; Jeong, Gwang Woo; Kang, Heoung Keun

1999-01-01

To evaluate the usefulness of CT angiography in patients with implantation of metallic stent for stenosed internal carotid artery. Seven patients with atherosclerotic stenosis of the internal carotid artery underwent metallic stent implantation. All were male and their ages ranged from 36 to 69 years. A total of seven stents were placed in the internal carotid artery in five patients and in the carotid bifurcation in two. Spiral CT scans were obtained and CT angiographic images were reconstructed using MPR or curved MPR techniques at a workstation. The interval between CT and conventional angiography did not exceed six days except in one patient, in whom it was 61days. CT and conventional angiography were compared for stent position with respect to the carotid bifurcation, stent deformation, intraluminal filling defect, and luminal caliber and outflow. Luminal patency of the implanted stent was measured according to NASCET(North American Symptomatic Carotid Endarterectomy Trial) criteria, and statistically processed (p>.05). The presence or absence of intrastent thrombus and vascular wall calcification was determined using axial source images. In all patients, CT angiographic findings matched those obtained by conventional angiography. Complications such as migration or deformation of an implanted stent, intraluminal filling defect, change of luminal caliber or outflow of implanted stent were not observed in any patient. In two studies in which Wilcoxon signed rank test was used, degree of stent expansion correlated closely(p=0.237). Axial source images showed that in no patient was an intrastent thrombus present, though in five, vascular wall calcification of internal carotid arteries outside the stent was noted. CT angiography is useful for the assessment of positional change, occlusion, and luminal patency of a stent-implanted internal carotid artery

Arterial healing following primary PCI using the Absorb everolimus-eluting bioresorbable vascular scaffold (Absorb BVS) versus the durable polymer everolimus-eluting metallic stent (XIENCE) in patients with acute ST-elevation myocardial infarction

DEFF Research Database (Denmark)

Räber, Lorenz; Onuma, Yoshinobu; Brugaletta, Salvatore

2015-01-01

Aims: The Absorb bioresorbable vascular scaffold (Absorb BVS) provides similar clinical outcomes compared with a durable polymer-based everolimus-eluting metallic stent (EES) in stable coronary artery disease patients. ST-elevation myocardial infarction (STEMI) lesions have been associated with d...

Development of a dynamic in vitro model of a stented blood vessel to evaluate the effects of stent strut material selection and surface coating on smooth muscle cell response

Science.gov (United States)

Winn, Bradley Huegh

Cardiovascular disease is the leading cause of mortality in The United States and Europe, accounting for approximately half of all deaths. The most common form of cardiovascular disease is atherosclerosis, which is characterized by the formation of fatty atheromatous plaques that can grow to occlude the vessel lumen, thus causing ischemia distal to the occlusion. This is commonly treated using balloon angioplasty, which is usually done in conjunction with the deployment of a stent. Stent deployment helps hold the vessel open following the local injury caused by balloon inflation and prevents elastic recoil and subsequent negative remodeling. Stenting has been shown to significantly reduce restenosis rates from approximately 20-50% without a stent to about 10-30% with stent deployment. However, restenosis still remains the main cause of long-term stent failure. In basic terms, a balloon angioplasty procedure is a forceful displacement of an atherosclerotic lesion serving to widen the vessel lumen to increase blood flow. This procedure causes stretching of the vessel wall, tears in the atherosclerotic plaques, and general damage to the vessel in turn signaling a complex cascade of thrombosis, inflammation, intimal thickening, and vascular remodeling. Stent deployment also further complicates the immunological response by triggering a foreign body response from the implantation of a biomaterial into the body. When performing an angioplasty procedure, particularly in conjunction with stent deployment, a certain degree of vascular injury is inevitable. However, the initial injury can be further complicated by the body's local reaction to the implanted biomaterial, the severity of which can ultimately dictate the degree of restenosis and subsequently affect procedural success. The proliferative response of VSMCs to the various afore mentioned stimuli results in the formation of often copious amounts of neointimal tissue, generally known as intimal hyperplasia. The

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

Late effects of low-energy gamma-emitting stents in a rabbit iliac artery model

International Nuclear Information System (INIS)

Strauss, Bradley H.; Li, Chris; Whittingham, Heather A.; Tio, Fermin O.; Kutryk, Michael J.B.; Janicki, Christian; Sparkes, John D.; Turnlund, Todd; Sweet, William L.

2002-01-01

Purpose: To determine the long-term dose response of novel low-dose γ-emitting stents in a rabbit iliac artery model. Methods and Materials: Control stents (n=24) and 103 Pd stents 1.0 to 4.0 mCi (n=36) were implanted in the iliac arteries of 30 New Zealand rabbits. Stents were evaluated by intravascular ultrasound (immediately post procedure and before killing) and by histomorphometry. Results: At 26 weeks, 28 rabbits were killed, with no evidence of stent thrombosis. In the body of the stent there was a dose-response relationship with 50% inhibition of intimal hyperplasia at the highest activity compared to control stents (p=0.07) and a significant increase in intimal hyperplasia at the lowest activity (p 103 Pd stents is feasible with reduction of in-stent hyperplasia in a dose-related manner. However, significant narrowing at the stent edges, increased in-stent hyperplasia at lower activities, and incomplete vascular healing with persistence of immature neointima at higher activities are significant limitations

Immediate outcomes of eptifibatide therapy during intracoronary stent implantation.

Science.gov (United States)

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

2016-01-01

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

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

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...

In-stent restenosis of innominate artery with critical stenosis of right internal carotid artery

International Nuclear Information System (INIS)

Hussain, S.; Raza, A.; Ahmed, W.

2011-01-01

A lady with aortitis syndrome developed in-stent restenosis (ISR) of the innominate artery stent and critical stenosis of right internal carotid artery. The therapeutic challenge was gaining access to the carotid vessel, after treating the innominate artery ISR and all the while using distal protection to circumvent potential cerebral embolism. Percutaneous transluminal angioplasty (PTA) with or without stenting is a safe therapeutic option for re-vascularization of the supra aortic vessels. In the event of re-stenosis, re-treatment with PTA and stenting is safe. Ample evidence-base exists now for carotid artery stenting (CAS) in preference to carotid endarterectomy in patients with stenotic lesions of the carotid vessels. (author)

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

Science.gov (United States)

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

The effect of stent structure changes on the hemodynamics and the formation of in-stent restenosis

International Nuclear Information System (INIS)

Wu Xia; Xu Ke; Xiao Liang; Zhang Xitong; Su Hongying; Feng Bo

2009-01-01

Objective: To investigate the effect of stent structure changes on the formation of in-stent restenosis by studying the influence of these changes on the shear force to the vascular wall, on the velocity of flow and on the flow pattern. Methods: Five stent models were established by using Pro/engineer wildfire 3.0. Model A was regarded as control structure. On the base structure of model A, transverse link component was added to form model B, and vertical link component was added to form model C. The thickness of model D was twice than that of model A, and the meshes density of model E was twice than that of model A. Fluid models were built up by importing these stent models into computational fluid dynamics (CFD) software ansys11.0-CFX, then, CFD analysis was proceeded to study the effect of stent structure on hemodynamics. Results: After the stents were implanted, the percentage of low wall shear stress on the surface of model A, B, C, D and E was 7.78%, 6.65%, 1.48%, 16.52% and 12.12%, respectively. The percentage of D and E was obviously larger than that of A, while the percentage of B was markedly smaller than that of A. The velocity vector on the cross-sectional planes showed that the low velocity and eddy areas in D and E were much larger than that in A, while this area in C was smaller than that in A. Conclusion: The stent structure changes can cause obvious changes in hemodynamics in the implanted vessels. The increase in the thickness and meshes density of the stent is the main factor that induces the formation of low wall shear stress, which will precipitate the development of in-stent restenosis. The added vertical link component will reduce the area of low wall shear stress as well as the occurrence of in-stent restenosis. (authors)

Stenting-plasty with brachial puncture in the treatment of subclavian steal syndrome

International Nuclear Information System (INIS)

Chen Quan; Jing Zaiping; Zhao Zhiqing; Feng Xiang; Lu Qingsheng; Mei Zhijun

2007-01-01

Objective: To study the clinical effect of stenting-plasty with retrograde brachial puncture for subclavian steal syndrome patients. Methods: To analyze the clinical results of stenting-plasty with retrograde brachial puncture in 15 patients with subclavian steal syndrome. Results: MRA or DSA showed the subclavian arteries with different degrees of stenosis (80%-100%) in all patients. Stenting-plasty with retrograde brachia] puncture was used in all patients. After placement of wall or polmaz stent, the pulse recovered and the syndrome disappeared. Postoperative angiography showed patency of the artery and stent. The patients were followed up for 3-30 months without recurrence of symptoms. Conclusions: Stenting-plasty with retrograde brachial puncture is a rather proper method to treat subclavian steal syndrome with more coincidence to the vascular anatomy, decrease the maneuver trouble and increase the successful rate. (authors)

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.

Enterprise stenting for intracranial aneurysm treatment induces dynamic and reversible age-dependent stenosis in cerebral arteries.

Science.gov (United States)

Gao, Bulang; Safain, Mina G; Malek, Adel M

2015-04-01

Although intracranial stenting has been associated with in-stent stenosis, the vascular response of cerebral vessels to the deployment of the Enterprise vascular reconstruction device is poorly defined. To evaluate the change in parent vessel caliber that ensues after Enterprise stent placement. Seventy-seven patients with 88 aneurysms were treated using Enterprise stent-assisted coil embolization and underwent high-resolution three-dimensional rotational angiography followed by three-dimensional edge-detection filtering to remove windowing-dependence measurement artifact. Orthogonal diameters and cross-sectional areas (CSAs) were measured proximal and distal on either side of the leading stent edge (points A, B), trailing stent edge (points D, E), and at mid-stent (point C). Enterprise stent deployment caused an instant increase in the parent artery CSA by 8.98% at D, which was followed 4-6 months later by significant in-stent stenosis (15.78% at A, 27.24% at B, 10.68% at C, 32.12% at D, and 28.28% at E) in the stented artery. This time-dependent phenomenon showed resolution which was complete by 12-24 months after treatment. This target vessel stenosis showed significant age dependence with greater response in the young. No flow-limiting stenosis requiring treatment was observed in this series. Use of the Enterprise stent is associated with a significant dynamic and spontaneously resolvable age-dependent in-stent stenosis. Further study is warranted on the clinical impact, if any, of this occurrence. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Microstructure and corrosion properties of as sub-rapid solidification Mg-Zn-Y-Nd alloy in dynamic simulated body fluid for vascular stent application.

Science.gov (United States)

Wang, Jun; Wang, Liguo; Guan, Shaokang; Zhu, Shijie; Ren, Chenxing; Hou, Shusen

2010-07-01

Magnesium alloy stent has been employed in animal and clinical experiment in recent years. It has been verified to be biocompatible and degradable due to corrosion after being implanted into blood vessel. Mg-Y-Gd-Nd alloy is usually used to construct an absorbable magnesium alloy stent. However, the corrosion resistant of as cast Mg-Y-Gd-Nd alloy is poor relatively and the control of corrosion rate is difficult. Aiming at the requirement of endovascular stent in clinic, a new biomedical Mg-Zn-Y-Nd alloy with low Zn and Y content (Zn/Y atom ratio 6) was designed, which exists quasicrystals to improve its corrosion resistance. Additionally, sub-rapid solidification processing was applied for preparation of corrosion-resisting Mg-Zn-Y-Nd and Mg-Y-Gd-Nd alloys. Compared with the as cast sample, the corrosion behavior of alloys in dynamic simulated body fluid (SBF) (the speed of body fluid: 16 ml/800 ml min(-1)) was investigated. The results show that as sub-rapid solidification Mg-Zn-Y-Nd alloy has the better corrosion resistance in dynamic SBF due to grain refinement and fine dispersion distribution of the quasicrystals and intermetallic compounds in alpha-Mg matrix. In the as cast sample, both Mg-Zn-Y-Nd and Mg-Y-Gd-Nd alloys exhibit poor corrosion resistance. Mg-Zn-Y-Nd alloy by sub-rapid solidification processing provides excellent corrosion resistance in dynamic SBF, which open a new window for biomedical materials design, especially for vascular stent application.

Surgical treatment of massive bleeding of a right aberrant subclavian artery after oesophageal stent removal

Directory of Open Access Journals (Sweden)

Michael Raum

2018-06-01

Full Text Available We report a case of a 9-year-old female who required surgical treatment and resuscitation after severe transoesophageal bleeding of a right aberrant subclavian artery (RASA. Bleeding of this RASA was caused by a mechanical irritation due to an oesophageal stent. The stent was placed weeks before to dilate the oesophagus after accidental ingestion of a caustic agent. Although conservative management of benign oesophageal stenosis in children is highly recommended, there are still some major complications to be considered. To avoid erosion of aberrant subclavian artery vascular rings and slings, as described in several case reports, these vessels should be excluded by computed tomography (CT or magnetic resonance imaging (MRI scans before placement of oesophageal stents. This case suggests that management of caustic ingestion in children is still a major challenge in paediatric surgical departments. Keywords: Paediatric surgery, Chemical Burn, Oesophageal stenosis, Oesophageal stenting, Vascular abnormalities, Right aberrant subclavian artery

Development of epigallocatechin gallate-eluting polymeric stent and its physicochemical, biomechanical and biological evaluations

International Nuclear Information System (INIS)

Han, Dong-Wook; Lee, Jun Jae; Jung, Duk-Young; Park, Jong-Chul; Hyon, Suong-Hyu

2009-01-01

Localized drug delivery from drug-eluting stents has been accepted as one of the most promising treatment methods for preventing restenosis after stenting. However, hypersensitivity reactions caused by their nonresorbable polymer coatings and bare-metal stents may result in serious clinical sequelae. Epigallocatechin-3-O-gallate (EGCG), the predominant catechin from tea, has been shown to exert anti-thrombotic, anti-inflammatory and anti-proliferative activities. In this study, it was hypothesized that sustainedly released EGCG from biodegradable poly(lactide-co-ε-caprolactone, PLCL) would suppress the proliferation of vascular smooth muscle cells (VSMCs). EGCG-releasing PLCL (E-PLCL) was prepared by blending PLCL with EGCG. The surface morphology, roughness and melting temperature of PLCL were not changed despite EGCG addition. EGCG was uniformly dispersed into E-PLCL and sustainedly released for periods up to 7 days by controlled diffusion rather than PLCL degradation. Moreover, EGCG did not affect tensile strength at break, but significantly increased the elastic modulus of PLCL. The proliferation of VSMCs onto E-PLCL was significantly suppressed although the cell attachment onto E-PLCL had been higher than that onto PLCL. On the other hand, EGCG-eluting polymeric stents were prepared with neither cracks nor webbings between struts, and their structural integrity was maintained without delamination or destruction. These results suggest that E-PLCL can be potentially applied for fabricating an EGCG-eluting vascular stent, namely an EGCG-eluting polymeric stent, or even an EGCG-releasing polymer-coated metal stent, to prevent thrombosis, inflammation and in-stent restenosis.

Development of epigallocatechin gallate-eluting polymeric stent and its physicochemical, biomechanical and biological evaluations

Energy Technology Data Exchange (ETDEWEB)

Han, Dong-Wook [Department of Nanomedical Engineering, College of Nanoscience and Nanotechnology, Pusan National University, Busan 609-735 (Korea, Republic of); Lee, Jun Jae [Division of Advanced Fibro-Science, Kyoto Institute of Technology, Kyoto 606-8585 (Japan); Jung, Duk-Young [Senior Products Industrial Center, Busan Techno-Park, Busan-617-030 (Korea, Republic of); Park, Jong-Chul [Cellbiocontrol Laboratory, Department of Medical Engineering, Yonsei University College of Medicine, Seoul 120-752 (Korea, Republic of); Hyon, Suong-Hyu, E-mail: nanohan@pusan.ac.k, E-mail: biogen@frontier.kyoto-u.ac.j [Department of Medical Simulation Engineering, Institute for Frontier Medical Sciences, Kyoto University, Kyoto 606-8507 (Japan)

2009-08-15

Localized drug delivery from drug-eluting stents has been accepted as one of the most promising treatment methods for preventing restenosis after stenting. However, hypersensitivity reactions caused by their nonresorbable polymer coatings and bare-metal stents may result in serious clinical sequelae. Epigallocatechin-3-O-gallate (EGCG), the predominant catechin from tea, has been shown to exert anti-thrombotic, anti-inflammatory and anti-proliferative activities. In this study, it was hypothesized that sustainedly released EGCG from biodegradable poly(lactide-co-epsilon-caprolactone, PLCL) would suppress the proliferation of vascular smooth muscle cells (VSMCs). EGCG-releasing PLCL (E-PLCL) was prepared by blending PLCL with EGCG. The surface morphology, roughness and melting temperature of PLCL were not changed despite EGCG addition. EGCG was uniformly dispersed into E-PLCL and sustainedly released for periods up to 7 days by controlled diffusion rather than PLCL degradation. Moreover, EGCG did not affect tensile strength at break, but significantly increased the elastic modulus of PLCL. The proliferation of VSMCs onto E-PLCL was significantly suppressed although the cell attachment onto E-PLCL had been higher than that onto PLCL. On the other hand, EGCG-eluting polymeric stents were prepared with neither cracks nor webbings between struts, and their structural integrity was maintained without delamination or destruction. These results suggest that E-PLCL can be potentially applied for fabricating an EGCG-eluting vascular stent, namely an EGCG-eluting polymeric stent, or even an EGCG-releasing polymer-coated metal stent, to prevent thrombosis, inflammation and in-stent restenosis.

Ultra-hydrophilic stent platforms promote early vascular healing and minimise late tissue response: a potential alternative to second-generation drug-eluting stents.

Science.gov (United States)

Kolandaivelu, Kumaran; Bailey, Lynn; Buzzi, Stefano; Zucker, Arik; Milleret, Vincent; Ziogas, Algirdas; Ehrbar, Martin; Khattab, Ahmed A; Stanley, James R L; Wong, Gee K; Zani, Brett; Markham, Peter M; Tzafriri, Abraham R; Bhatt, Deepak L; Edelman, Elazer R

2017-04-20

Simple surface modifications can enhance coronary stent performance. Ultra-hydrophilic surface (UHS) treatment of contemporary bare metal stents (BMS) was assessed in vivo to verify whether such stents can provide long-term efficacy comparable to second-generation drug-eluting stents (DES) while promoting healing comparably to BMS. UHS-treated BMS, untreated BMS and corresponding DES were tested for three commercial platforms. A thirty-day and a 90-day porcine coronary model were used to characterise late tissue response. Three-day porcine coronary and seven-day rabbit iliac models were used for early healing assessment. In porcine coronary arteries, hydrophilic treatment reduced intimal hyperplasia relative to the BMS and corresponding DES platforms (1.5-fold to threefold reduction in 30-day angiographic and histological stenosis; p<0.04). Endothelialisation was similar on UHS-treated BMS and untreated BMS, both in swine and rabbit models, and lower on DES. Elevation in thrombotic indices was infrequent (never observed with UHS, rare with BMS, most often with DES), but, when present, correlated with reduced endothelialisation (p<0.01). Ultra-hydrophilic surface treatment of contemporary stents conferred good healing while moderating neointimal and thrombotic responses. Such surfaces may offer safe alternatives to DES, particularly when rapid healing and short dual antiplatelet therapy (DAPT) are crucial.

Metallic stent placement in hemodialysis graft patients after insufficient balloon dilation

International Nuclear Information System (INIS)

Liang, Huei-Lung; Pan, Huay-Ben; Lin, Yih-Huie; Chen, Chiung-Yu; Lai, Pin-Hong; Yang, Chien-Fang; Chung, Hsiao-Min; Wu, Tung-Ho; Chou, Kang-Ju

2006-01-01

We wanted to report our experience of metallic stent placement after insufficient balloon dilation in graft hemodialysis patients. Twenty-three patients (13 loop grafts in the forearm and 10 straight grafts in the upper arm) underwent metallic stent placement due to insufficient flow after urokinase thrombolysis and balloon dilation. The indications for metallic stent deployment included 1) recoil and/or kinked venous stenosis in 21 patents (venous anastomosis: 17 patients, peripheral outflow vein: four patients); and 2) major vascular rupture in two patients. Metallic stents 8-10mm in diameter and 40-80 mm in length were used. Of them, eight stents were deployed across the elbow crease. Access patency was determined by clinical follow-up and the overall rates were calculated by Kaplan-Meier survival analysis. No procedure-related complications (stent fracture or central migration) were encountered except for a delayed Wallstent shortening/migration at the venous anastomosis, which resulted in early access failure. The overall primary and secondary patency rates (±standard error) of all the vascular accesses in our 23 patients at 3, 6, 12 and 24 months were 69%±9 and 88%±6,41% ±10 and 88%±6, 30%±10 and 77%±10, and 12%±8 and 61%±13, respectively. For the forearm and upper-arm grafts, the primary and secondary patency rates were 51%±16 and 86%±13 vs 45%±15 and 73%±13 at 6 months, and 25%±15 and 71%±17 vs 23%±17 and 73%±13 at 12 months (ρ = .436 and .224), respectively. Metallic stent placement is a safe and effective means for treating peripheral venous lesions in dialysis graft patients after insufficient balloon dilation. No statistically difference in the patency rates between the forearm and upper-arm patient groups was seen

An experimental study on the influence of the intravascular gianturco type stents on the vascular structures

Energy Technology Data Exchange (ETDEWEB)

Choe, Yeon Hyeon [Sejong General Hospital, Bucheon (Korea, Republic of); Park, Jae Hyung; Han, Joon Koo; Han, Man Chung; Kim, Chu Wan [College of Medicine, Seoul National University, Seoul (Korea, Republic of)

1991-07-15

Twenty-seven Gianturco-type self-expandable stainless steel intravascular stents were placed into the infrarenal abdominal aortas (n=17) and inferior venae cavae (n=10) in 14 mongrel dogs. In 8 aortas, stents were delivered after balloon catheter-induced denudation of the intima, and in 4 out of the 8 aortas, the stents were also placed into the normal sites to compare the neointimal thickness of the normal and denuded sites. Angiography, light microscopic, and scanning electron microscopic examinations were performed after 1 week (n=1), 2 weeks (n=6), 3 weeks (n=5), and 6 weeks (n=2). The patency rate and thrombosis rate were 100% and 35% in the aortas and 100% and 60% in the inferior venae cavae. The aortic stent wires were covered with thin fibrinous membrane after 1 week. Nearly complete transparent neointimal covering was found in the aortas and caval veins after 2 weeks. There was no significant difference in intimal thickness between the denuded and normal aortas after 2 weeks ({rho} =0.51) and 3 weeks ({rho} =0.56). In 4 dogs with caval vein stents, there was evidence of hemorrhage infarction in the lungs. The thrombosis rate of 12 stents with a stent-artery ratio (SAR) of 1.5 or higher was 41%, while there was no thrombus on the 4 stents with SAR 1.2 or lower, except for 1 specimen after 1 week. It is suggested that stents with SAR 1.2 or lower are more suitable. The high thrombosis rate of the inferior venae cavae may be related with slow blood flow.

Bronchoscopic guidance of endovascular stenting limits airway compression.

Science.gov (United States)

Ebrahim, Mohammad; Hagood, James; Moore, John; El-Said, Howaida

2015-04-01

Bronchial compression as a result of pulmonary artery and aortic arch stenting may cause significant respiratory distress. We set out to limit airway narrowing by endovascular stenting, by using simultaneous flexible bronchoscopy and graduated balloon stent dilatation, or balloon angioplasty to determine maximum safe stent diameter. Between August 2010 and August 2013, patients with suspected airway compression by adjacent vascular structures, underwent CT or a 3D rotational angiogram to evaluate the relationship between the airway and the blood vessels. If these studies showed close proximity of the stenosed vessel and the airway, simultaneous bronchoscopy and graduated stent re-dilation or graduated balloon angioplasty were performed. Five simultaneous bronchoscopy and interventional catheterization procedures were performed in four patients. Median age/weight was 33 (range 9-49) months and 14 (range 7.6-24) kg, respectively. Three had hypoplastic left heart syndrome, and one had coarctation of the aorta (CoA). All had confirmed or suspected left main stem bronchial compression. In three procedures, serial balloon dilatation of a previously placed stent in the CoA was performed and bronchoscopy was used to determine the safest largest diameter. In the other two procedures, balloon testing with simultaneous bronchoscopy was performed to determine the stent size that would limit compression of the adjacent airway. In all cases, simultaneous bronchoscopy allowed selection of an ideal caliber of the stent that optimized vessel diameter while minimizing compression of the adjacent airway. In cases at risk for airway compromise, flexible bronchoscopy is a useful tool to guide endovascular stenting. Maximum safe stent diameter can be determined without risking catastrophic airway compression. © 2014 Wiley Periodicals, Inc.

Bioabsorbable drug-eluting vascular scaffold for the treatment of coronary in-stent restenosis: A two center registry

International Nuclear Information System (INIS)

Moscarella, Elisabetta; Varricchio, Attilio; Stabile, Eugenio; Franzone, Anna; Granata, Francesco; Rapacciuolo, Antonio; Galasso, Gennaro; Capozzolo, Claudia; Cirillo, Plinio

2015-01-01

Background/purpose: Coronary in-stent restenosis (ISR) is a clinical problem for which a satisfactory solution has not been found yet. Bioabsorbable drug eluting vascular scaffolds (BVSs) provide transient vessel scaffolding combined with prolonged drug delivery capability. The aim of this study was to investigate the safety of BVS for the treatment of coronary ISR. Methods/materials: Between January 2013 and June 2013, 27 patients (31 lesions), presenting with either stable or unstable angina due to coronary ISR, were enrolled in a single arm, prospective, open label registry. Primary end point was the occurrence of target vessel revascularization (TVR) at 12 months. Secondary end point was the composite of death, myocardial infarction and TVR at 12 months. Results: A diffuse ISR pattern was present in 70% of the lesions; mean lesion length was 34.6 ± 15. BVS was successfully implanted in all patients with no in hospital MACE. At twelve months of follow up, MACE rate was 18.5%. One patient died for non-cardiac reason, one patient died due to a possible stent thrombosis and TVR was necessary in 3 patients (11.1%). Conclusions: Our data suggest that BVS is safe and technically feasible for treatment of long and diffuse coronary ISR. These data could be considered hypothesis generator for a randomized clinical trial. - Highlights: • A safe therapeutic option for the treatment of diffuse ISR; • Technically feasible; • Associated to a low rate of restenosis recurrence at nine month.

Bioabsorbable drug-eluting vascular scaffold for the treatment of coronary in-stent restenosis: A two center registry

Energy Technology Data Exchange (ETDEWEB)

Moscarella, Elisabetta [Division of Cardiology, Seconda Università degli studi di Napoli, AO Dei cColli, PO Monaldi (Italy); Varricchio, Attilio [Division of Cardiology, Department of Advanced Biomedical Sciences, University of Napoli “Federico II”, Napoli (Italy); Stabile, Eugenio, E-mail: geko50@hotmail.com [Laboratory of Invasive Cardiology, Dipartimento di Cardiologia, Presidio Ospedaliero “Monaldi”, Azienda Ospedaliera “Dei Colli”, Napoli (Italy); Franzone, Anna [Laboratory of Invasive Cardiology, Dipartimento di Cardiologia, Presidio Ospedaliero “Monaldi”, Azienda Ospedaliera “Dei Colli”, Napoli (Italy); Granata, Francesco [Division of Cardiology, Seconda Università degli studi di Napoli, AO Dei cColli, PO Monaldi (Italy); Rapacciuolo, Antonio; Galasso, Gennaro [Laboratory of Invasive Cardiology, Dipartimento di Cardiologia, Presidio Ospedaliero “Monaldi”, Azienda Ospedaliera “Dei Colli”, Napoli (Italy); Capozzolo, Claudia [Division of Cardiology, Department of Advanced Biomedical Sciences, University of Napoli “Federico II”, Napoli (Italy); Cirillo, Plinio [Laboratory of Invasive Cardiology, Dipartimento di Cardiologia, Presidio Ospedaliero “Monaldi”, Azienda Ospedaliera “Dei Colli”, Napoli (Italy); and others

2015-10-15

Background/purpose: Coronary in-stent restenosis (ISR) is a clinical problem for which a satisfactory solution has not been found yet. Bioabsorbable drug eluting vascular scaffolds (BVSs) provide transient vessel scaffolding combined with prolonged drug delivery capability. The aim of this study was to investigate the safety of BVS for the treatment of coronary ISR. Methods/materials: Between January 2013 and June 2013, 27 patients (31 lesions), presenting with either stable or unstable angina due to coronary ISR, were enrolled in a single arm, prospective, open label registry. Primary end point was the occurrence of target vessel revascularization (TVR) at 12 months. Secondary end point was the composite of death, myocardial infarction and TVR at 12 months. Results: A diffuse ISR pattern was present in 70% of the lesions; mean lesion length was 34.6 ± 15. BVS was successfully implanted in all patients with no in hospital MACE. At twelve months of follow up, MACE rate was 18.5%. One patient died for non-cardiac reason, one patient died due to a possible stent thrombosis and TVR was necessary in 3 patients (11.1%). Conclusions: Our data suggest that BVS is safe and technically feasible for treatment of long and diffuse coronary ISR. These data could be considered hypothesis generator for a randomized clinical trial. - Highlights: • A safe therapeutic option for the treatment of diffuse ISR; • Technically feasible; • Associated to a low rate of restenosis recurrence at nine month.

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

Radiological findings and interventions for iatrogenic vascular injuries

International Nuclear Information System (INIS)

Lee, Kyoung Ho; Chung, Jin Wook; Kim, Tae Kyoung; Han, Sang Wook; Lee, Jong Seog; Park, Jae Hyung; Kim, Jong Hyo; Han, Man Chung

1998-01-01

The purpose of this study is to evaluate the radiological findings and effectiveness of radiological interventions in patients with iatrogenic vascular injuries. We analyzed 50 patients with iatrogenic vascular injuries treated with radiological intervention. The causes of injuries were surgery (n=20), cardiovascular intervention (n=15), non-cardiovascular radiological intervention (n=14), and endoscopic intervention (n=1). The injury had resulted in hemorrhage in 35 cases. The iliac and/or femoral, hepatic, and renal vessels were commonly injured. Angiography, ultrasonography with Doppler examination, CT, and CT angiography were performed to diagnose vascular injuries and guide the radiological intervention. The mean follow-up period was 23 months and in 16 cases was more than one year. the major radiological findings were extravasation, pseudoaneurysm, arteriovenous shunt, or vascular obstruction. To control these lesions, radiological interventions such as embolization (n=36), local urokinase administration, stent insertion, foreign body removal, ultrasonography-guided compression, or stent-graft insertion were performed. The clinical problems were immediately controlled by the single trials of radiological interventions and did not recur in 40 cases (80%). Radiological examinations and interventions are useful in cases with iatrogenic vascular injuries. (author). 14 refs., 4 figs

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

A preliminary report on the effects of paclitaxel-impregnated stents on sheep nasal mucosa.

Science.gov (United States)

Herrmann, Brian W; Citardi, Martin J; Vogler, George; Gardner, Laura; Smith, Greg; Javer, Amin R; Burt, Helen M; Jackson, John; Kuhn, Frederick A

2004-01-01

Traditional frontal sinus stents serve only as mechanical devices. It has been proposed that stents also may serve as drug-delivery systems for the topical application of drugs that minimize postoperative scarring. Paclitaxel (Taxol), which has recognized antiscarring effects, may be incorporated via a polymeric formulation into standard rubber stents. The impact of topically applied paclitaxel on the morphology of the nasal mucosa is unknown. An adult sheep model was used for this study. A modified rubber T-tube stent (incorporating paclitaxel at varying dosages) was secured to each side of the septum in four animals (eight sides). An unmodified T-tube was placed on each side of one animal, a T-tube with the drug carrier (but no paclitaxel) was placed on each side of the second animal, and T-tubes with varying paclitaxel were placed on each side of the final two animals. After 4 weeks, animals were killed and the nasal mucosa was harvested. The nasal mucosa was sectioned and stained with hematoxylin and eosin. A pathologist then assessed the nasal mucosa for vascular congestion, glandular atrophy, chronic inflammation, mucosal metaplasia, and mucosal ulceration. No consistent histopathological differences were noted in the specimens. All specimens showed varying degrees of vascular congestion, glandular atrophy, chronic inflammation, and mucosal metaplasia; the paclitaxel-impregnated stents were not consistently associated with more severe mucosal injury. Finally, mucosal ulceration was noted to be very rare in all specimens. This preliminary report describes the impact of paclitaxel-impregnated stents on sheep nasal mucosa, which tolerated these stents very well. Because paclitaxel minimizes scarring reactions at very low concentrations, paclitaxel-impregnated stents may prove useful in clinical situations in which frontal sinus stenting is deemed necessary. Additional investigations with animal models, as well as clinical trials, may be warranted.

Device-specificity of vascular healing following implantation of bioresorbable vascular scaffolds and bioabsorbable-polymer metallic drugeluting stents in human coronary arteries. The ESTROFA OCT BVS vs. BP-DES study.

Science.gov (United States)

de la Torre Hernandez, Jose Maria; Gonzalo, Nieves; Otaegui, Imanol; Rumoroso, Jose R; Gutiérrez, Hipólito; Alfonso, Fernando; Marti, Gerard; Serrador Frutos, Ana; Brugaletta, Salvatore; Gomez Menchero, Antonio; Garcia Camarero, Tamara; Biagioni, Corina; Escaned, Javier

2018-06-12

We sought to compare vascular healing with bioresorbable everolimus-eluting vascular scaffolds (BVS) and drug-eluting stents with bioabsorbable polymers (BP-DES) at 6 and 12 months implanted both in same patients. Multicenter and prospective study including patients with at least two comparable lesions to treat. In every patient both BVS and BP-DES (Synergy™, Orsiro™ or Biomatrix Flex™) were implanted by lesion randomization. Patients included were evaluated with optical coherence tomography at 6 or 12 months (2:1). Finally, 68 patients had examination at 6 months and 27 patients at 12 months. Uncovered struts rates at 6 months were 1.7±3.2% for BVS and 5.3±5.6% for BP-DES (p=0.0001) and at 12 months 0.48±0.72% and 4.8±5% respectively (p=0.001). Rates of strut malapposition were significantly lower with BVS. There was no significant intra-patient correlation BP-DES / BVS for endpoints. Evaginations were more frequent and larger with BVS. Discontinuities in BVS were observed in 19.4% at 6 months and 14.3% at 12 months. Vascular healing with BVS and BP-DES could be more device-specific than patient-specific. At follow-up, BVS presented less uncovered or non-apposed struts than BP-DES but more frequent and larger evaginations. Discontinuities in BVS were relatively frequent at both time points.

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.

Arterial stenting with self-expandable and balloon-expandable endoprostheses

NARCIS (Netherlands)

W.J. van der Giessen (Wim); P.W.J.C. Serruys (Patrick); L.J. van Woerkens (L.); K.J. Beatt (Kevin); W.J. Visser (Willy); J.F. Jongkind; R.H. van Bremen (Robert); E. Ridderhof; H. van Loon (Heleen); L.K. Soei (Lou Kie); H.M.M. van Beusekom (Heleen); P.D. Verdouw (Pieter)

1990-01-01

textabstractCoronary angioplasty is complicated by acute occlusion (within 24 hours) and late restenosis (within 6 months) in 2-5% and 20-40% of the cases, respectively. Vascular endoprostheses (stents) may provide the cardiologist with a solution to some of these complications. Several

MRI-compatible Nb–60Ta–2Zr alloy used for vascular stents: Haemocompatibility and its correlation with protein adsorption

Energy Technology Data Exchange (ETDEWEB)

Li, Xiu-Mei [School of Stomatology, China Medical University, 117 Nanjing North Street, Shenyang 110002 (China); Li, Hui-Zhe; Wang, Shao-Ping [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China); Huang, Hsun-Miao; Huang, Her-Hsiung [Biomaterials and Electrochemistry Lab, Department of Dentistry, National Yang-Ming University, Taipei City 112, Taiwan (China); Ai, Hong-Jun, E-mail: aih0620@yahoo.com.cn [School of Stomatology, China Medical University, 117 Nanjing North Street, Shenyang 110002 (China); Xu, Jian, E-mail: jianxu@imr.ac.cn [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China)

2014-09-01

Nb–60Ta–2Zr is a newly developed MRI-compatible alloy used for vascular stents. In this work, its haemocompatibility was investigated, including platelet adhesion (lactate dehydrogenase activity), platelet activation (P-selectin expression), coagulation and haemolysis. For comparison, parallel assessments for these factors were performed for the niobium, tantalum, 316L stainless steel (316L SS) and L605 Co–Cr alloy (L605). In addition, albumin and fibrinogen were selected to examine the correlation of protein adsorption with platelet adhesion and metal surface properties. The propensity for platelet adhesion and activation on the Nb–60Ta–2Zr alloy was at nearly the same level as that for Nb and Ta but was slightly less than those of 316L SS and L605. The mitigated platelet adhesion and activation of the Nb–60Ta–2Zr alloy is associated with its decreased adsorption of fibrinogen. The Nb–60Ta–2Zr alloy has a longer clotting time and exhibits significantly superior thromboresistance than 316L SS and L605. Moreover, the haemolysis rate of the Nb–60Ta–2Zr alloy satisfies the bio-safety requirement of the ISO 10993–4 standard. The favourable haemocompatiblity of the Nb–60Ta–2Zr alloy provides evidence of its good biocompatibility and of its suitability as a candidate stent material. - Highlights: • The Nb–60Ta–2Zr alloy is less hydrophobic than the 316L SS and L605 alloy. • The Nb–60Ta–2Zr has slightly weak propensity for platelet adhesion and activation. • The Nb–60Ta–2Zr alloy results in a longer clotting time. • Haemolysis of Nb–60Ta–2Zr is slightly lower than that of 316L SS and L605. • The Nb–60Ta–2Zr alloy is a promising MRI-compatible stent material.

TIDES-ACS Trial: comparison of titanium-nitride-oxide coated bio-active-stent to the drug (everolimus)-eluting stent in acute coronary syndrome. Study design and objectives.

Science.gov (United States)

Colkesen, E B; Eefting, F D; Rensing, B J; Suttorp, M J; Ten Berg, J M; Karjalainen, P P; Van Der Heyden, J A

2015-02-01

Drug-eluting stents (DES), delivering antiproliferative drugs from a durable polymer, have shown to reduce in-stent restenosis after percutaneous coronary intervention (PCI) compared to bare-metal stents (BMS). However, they have been associated with a hypersensitivity reaction, delayed healing, and incomplete endothelialization, which may contribute to an increased risk of late stent thrombosis. Consequently, a prolonged duration of dual antiplatelet therapy (DAPT) is needed, with an increased risk of bleeding complication. A number of stent technologies are being developed in an attempt to modify late thrombotic events and DAPT duration. The Optimax™ stent is such a novel, next generation bioactive stent (BAS), in which a thicker layer of titanium-nitride-oxide coating is inserted over the stent struts. The rationale of this is to obtain more efficient and rapid vascular healing at the site of the stent implantation. The aim of TIDES-ACS Trial is to compare clinical outcome in patients presenting with ACS, treated with PCI using Optimax-BAS versus Synergy™-EES. Second objective is to explore whether the Optimax™-BAS use is superior compared with Synergy™-EES use with respect of hard end points (cardiac death, myocardial infarction [MI] and major bleeding). A prospective, randomized, multicenter trial (ClinicalTrials.gov Identifier: NCT02049229), will be conducted in interventional centres in Finland (six centres), France (five centres) and Holland (two centres), including a total of 1800 patients.

Treatment of carotid artery aneurysms with covered stents; Aneurysmabehandlung der Arteria carotis interna mit gecoverten Stents

Energy Technology Data Exchange (ETDEWEB)

Rohr, A.; Alfke, K.; Doerner, L.; Jansen, O. [UKSH Kiel (Germany). Neurochirurgie Neuroradiologie; Bartsch, T.; Stingele, R. [UKSH Kiel (Germany). Neurologie

2007-10-15

Purpose: Evaluation of the use of covered stents in treating pseudoaneurysms of the cervical and intracranial/extradural carotid artery and determination of the periprocedural and short- to mid-term complication rate. Materials and Methods: 8 patients with 9 spontaneous dissecting aneurysms of the cervical carotid artery - 5 of which were symptomatic - plus one patient with ofthalmoplegia due to an aneurysm of the cavernous carotid artery were studied. While the latter was treated with a PTFE-covered balloon-mounted stainless steel stent (Jostent/Graftmaster), a self-expanding PTFE-covered Nitonol Stent (Symbiot) was used in all other cases. Intervention was performed with local anesthesia. Aspirin and Clopidogrel were both used as antiplatelet drugs. Clinical signs and symptoms and vascular imaging with DS, MR, CT angiography and ultrasound were recorded during patient follow-up, with a mean follow-up period of 14.6 months (4 - 30). Results: We were able to treat 8 out of 10 aneurysms (80 %) using covered stents. The aneurysms were immediately occluded and the associated stenoses of the parent vessel were eliminated. No clinically relevant complications occurred during the procedure or in the follow-up interval. In two cases, elongation of the carotid artery prevented the stent from being positioned over the aneurysm neck. These cases were shown to be stable with the use of antiplatelet drugs. Conclusion: Covered stents can be used in the treatment of pseudoaneurysms of the carotid artery as an alternative to long-term antithrombotic medication or surgery. In our study treatment was effective (80 %) and free of complications in the short- and mid-term follow-up. Possible indications, technique and the use of imaging modalities for patient follow-up are discussed. (orig.)

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

Science.gov (United States)

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

1995-07-01

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

Current global status of carotid artery stent placement.

Science.gov (United States)

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

1998-05-01

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

Lesion-Related Carotid Angioplasty and Stenting with Closed-Cell Design without Embolic Protection Devices in High-Risk Elderly Patients-Can This Concept Work Out? A Single Center Experience Focusing on Stent Design.

Science.gov (United States)

Hopf-Jensen, Silke; Marques, Leonardo; Preiß, Michael; Müller-Hülsbeck, Stefan

2014-12-01

To compare the performance differences of three carotid artery stents in high-risk elderly patients without embolic protection devices (EPDs) on the basis of stent design, procedure-related complications, conveniences in handling, in-stent restenosis, 30-day outcome, and long-term follow-up. A total of 101 symptomatic internal carotid stenoses of 94 patients were prospectively treated with stent-protected angioplasty to 94 patients. Three closed-cell stents, one of those being hybrid cell design, were chosen depending on vascular anatomy: curved vessel, lesion length > 1 cm: 64 Carotid Wallstent (Boston Scientific, Natick, MA); curved vessel, lesion length  1 cm: 16 Xact (Vascular Abbott, Santa Clara, CA). Comparisons of demographics, procedures, and outcomes were performed. The mean age of patients was 73.1 years (standard deviation [SD], ± 7.9; range, 58-87 years), 71% of the patients were older than 70 years and 20% were octogenarians. Male/female ratio was 3.1:1. About 13.9% (14/101) had contralateral internal carotid artery occlusion. Overall peri-interventional complication rate was 2.9% and 30-day mortality rate was 1%. During the long-term follow-up (34 months, range 1-59) no ipsilateral stroke was documented. Ten deaths (three after MI) were recognized. Two in-stent restenosis were detected (> 70% North American Symptomatic Carotid Endarterectomy Trial) during follow-up, one patient was detected with previous carotid endarterectomy. Especially, if individual anatomical variance is considered, lesion-related stent-protected carotid angioplasty with lesion-adapted closed-cell design is an effective, reliable, safe, and comprehensible treatment option in symptomatic patients. Even without EPDs, the rate of complications is low, when compared with symptomatic carotid artery stenosis described in the literature. In-stent restenosis seems to play no significant role in follow-up.

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.

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.

The REMEDEE-OCT Study: An Evaluation of the Bioengineered COMBO Dual-Therapy CD34 Antibody-Covered Sirolimus-Eluting Coronary Stent Compared With a Cobalt-Chromium Everolimus-Eluting Stent in Patients With Acute Coronary Syndromes: Insights From Optical Coherence Tomography Imaging Analysis

NARCIS (Netherlands)

Jaguszewski, Milosz; Aloysius, Romila; Wang, Wei; Bezerra, Hiram G.; Hill, Jonathan; de Winter, Robbert J.; Karjalainen, Pasi P.; Verheye, Stefan; Wijns, William; Lüscher, Thomas F.; Joner, Michael; Costa, Marco; Landmesser, Ulf

2017-01-01

The aim of the present study was to evaluate vascular healing of the bioengineered COMBO Dual Therapy Stent compared with a cobalt-chromium (CoCr) everolimus-eluting stent (EES) as assessed by optical coherence tomography in patients with acute coronary syndromes. CD34+ cells promote endothelial

Magnetic resonance imaging of stents. Quantitative in vitro examination at 3 Tesla

International Nuclear Information System (INIS)

Reinhardt, Julia; Fachhochschule Jena; Nguyen-Trong, Thien-Hoa; Haehnel, Stefan; Bellemann, Matthias E.; Heiland, Sabine; Neurologische Universitaetsklinik Heidelberg

2009-01-01

The aim of this study was to qualitatively and quantitatively study MR artifacts of various stents on the basis of in vitro experiments. We were particularly interested whether sequence type and orientation of the stent with respect to the static magnetic field influences the artifact. We examined 18 stents of different material (nitinol, stainless steel, cobalt alloy), different design of the stent meshes (AccuLink, OmniLink, DynaLink, Xact, Protoge, Wallstent Monorail), different diameter (5-10 mm) and different length (18-58 mm) with a turbo spin echo (TSE), a 2D-fast low angle shot (FLASH) and a 3D-FLASH sequence. The MR images were examined qualitatively with respect to possible artifacts. Furthermore we examined the MR data quantitatively: The contrast-noise-ratio (CNR) was determined both within the stent and outside (within the tube); based on these values we calculated the transparency factor P, furthermore we calculated the apparent vascular lumen within the tube and within the stent. The stents made of stainless steel and cobalt alloy displayed severe susceptibility artifacts. Therefore the vessel lumen within the stent could not be assessed. The nitinol stents showed different artifact patterns: The AccuLink and DynaLink stents showed less artifacts compared to the Xact and Protoge stents. Besides the susceptibility artifacts we found artifacts due to RF shielding by the stent mesh, particularly in TSE sequences. A MR control of patients after stenting is possible and may yield diagnostic information when using the AccuLink or DynaLink stents. However, it is important to make sure that the stent is MR safe for the field strength used for the examination. (orig.)

肝内门腔分流术支架与血管支架组织成分的对比研究%Experimental comparison study of the tissue characteristics in transjugular intrahepalic portosystemic shunt and vascular stent

Institute of Scientific and Technical Information of China (English)

卢勤; 魏晓莹; 滕皋军; 安艳丽; 邓钢; 方文; 朱光宇; 牛焕章; 余辉; 李国昭; 王甄

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 simultaneouly.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 difierences of the tissues within the shunt and stent were analvzed with Kruskal 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 tissueElectron micmscopic 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 fibmblastic cells with normal organdie.The intimal tissues in vascular stent contained more fibers and fibroblasts cells.less smooth muscle cells.On immunohistoehemical staining,the tissues in restenotlc and Datent TIPS as well as the intimal tissues in vascular stent had strong positive expression for anti-SMCactin-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 tissues,normal liver tissues

Extracellular Matrix Molecules Facilitating Vascular Biointegration

Directory of Open Access Journals (Sweden)

Martin K.C. Ng

2012-08-01

Full Text Available All vascular implants, including stents, heart valves and graft materials exhibit suboptimal biocompatibility that significantly reduces their clinical efficacy. A range of biomolecules in the subendothelial space have been shown to play critical roles in local regulation of thrombosis, endothelial growth and smooth muscle cell proliferation, making these attractive candidates for modulation of vascular device biointegration. However, classically used biomaterial coatings, such as fibronectin and laminin, modulate only one of these components; enhancing endothelial cell attachment, but also activating platelets and triggering thrombosis. This review examines a subset of extracellular matrix molecules that have demonstrated multi-faceted vascular compatibility and accordingly are promising candidates to improve the biointegration of vascular biomaterials.

Angle change of the parent arteries after stent-assisted coil embolization of wide-necked intracranial bifurcation aneurysms

International Nuclear Information System (INIS)

Cho, W.-S.; Kang, H.-S.; Kim, J.E.; Kwon, O.-K.; Oh, C.W.; Cho, Y.D.; Han, M.H.

2014-01-01

Aim: To investigate the angle changes of the parent arteries after stent-assisted coil embolization of wide-necked intracranial bifurcation aneurysms. Materials and methods: The adjacent parent arterial angles before and after stent-assisted coil embolization were measured in 38 patients with aneurysms of the anterior communicating artery (ACoAA) and 41 patients with bifurcation aneurysms of the middle cerebral artery (MCABA). Variables were analysed in relation to the angle changes. Results: Vascular angles of the parent arteries significantly increased by 27.8° (±18.5°) immediately after stent-assisted coil embolization in 79 cases (p < 0.001), with 25.7° (±14.8°) in ACoAA and 29.7° (±21.4°) in MCABA, respectively. In 51 (64.6%) cases with follow-up angiography (mean interval 13.5 ± 4.1 months), vascular angles increased by 27.2° (±17.1°) immediately after treatment and further increased by 20.7° (±14.3°) at the last follow-up (all p < 0.001). More acute pre-stent angles of the parent arteries correlated with greater post-stent angle changes (p = 0.006). Younger age tended to be inversely related to post-stent angle changes (p = 0.091). Conclusion: Stent placement during coil embolization induced significant changes in the aneurysm–parent artery relationship. Further study is needed to elicit the association between angle change of the parent arteries and aneurysmal stability after coil embolization

Stent tunnel technique to save thrombosed native hemodialysis fistula with extensive venous aneurysm

Directory of Open Access Journals (Sweden)

Rabellino M

2017-07-01

Full Text Available Martin Rabellino,1 Guillermo J Rosa-Diez,2 Sergio A Shinzato,1 Pablo Rodriguez,1 Oscar A Peralta,1 Maria S Crucelegui,2 Rosario Luxardo,2 Agustina Heredia-Martinez,2 Mariela I Bedini-Rocca,2 Ricardo D García-Mónaco1 1Department of Angiography and Endovascular Therapy, 2Department of Nephrology, Hospital Italiano de Buenos Aires, Buenos Aires, Argentina Introduction and purpose: The increasing number of patients undergoing hemodialysis and the limited number of access sites have resulted in an increasing number of techniques to maintain vascular access for hemodialysis. Thrombosed arteriovenous (AV fistulas with large venous aneurysms have poor treatment results, with both endovascular and surgical techniques, leading to a high rate of definitive AV access loss. The purpose of this study was to review the feasibility and initial results of this novel endovascular treatment of thrombosed AV fistulas with large venous aneurysms.Materials and methods: A novel endovascular treatment technique of inserting nitinol auto-expandable uncovered stents stretching through the whole puncture site area, thus creating a tunnel inside the thrombus, was retrospectively analyzed and described.Results: A total of 17 stents were placed in 10 hemodialysis fistulas, with a mean venous coverage length of 17.8 cm. In all the cases, 100% technical success was achieved, with complete restoration of blood flow in all patients. There were no procedure-related complications. The mean follow-up was 167 days (range 60–420 days, with a primary and assisted patency of 80% and 100%, respectively. No multiple trans-stent struts-related complications were observed. Three stent fractures were diagnosed with plain films at the site of puncture without consequence in the venous access permeability.Conclusion: The “stent tunnel technique” is a feasible, safe and effective alternative to salvage native hemodialysis access, thus extending the function of the venous access with

Non-vascular interventional therapy for respiratory diseases

International Nuclear Information System (INIS)

Ji Hongjian; Chen Liping; Wang Hui; Cheng Yongde

2009-01-01

To review the recent literature relating to non-vascular interventional therapy of respiratory diseases. Metal airway stent insertion can immediately relieve tracheobronchial obstruction and improve pulmonary function. However, as there is a high occurrence of the restenosis after stent insertion, it should be very careful to use metal stenting to treat the benign airway obstruction. Compared with traditional lung volume reduction surgery in treating severe emphysema, bronchoscopic lung volume reduction appears to be effective, safe and less invasive, although its clinical usefullness need to be further proved. Endoscopic occlusion of bronchial fistula represents an effective alternative to surgical treatment. Percutaneous lung biopsy under ultrasound or CT guidance has been applied successfully in the management of both benign and malignant lesions. (authors)

Physical property and MR imaging of self-expandable metallic stents

Energy Technology Data Exchange (ETDEWEB)

Roh, Hong Gee; Kang, Sung Gwon; Cho, Young Kook; Kim, Hyung Jin; Lim, Myung Kwan; Cho, Soon Gu; Yoh, Kyu Tong; Suh, Chang Hae [Inha Univ., College of Medicine, Seoul (Korea, Republic of)

1998-09-01

In order to furnish basic information prior to their use, the physical properties of various self-expandable metallic stents and their MR characteristics were evaluated. Four commercially available self-expandable metallic stents-Gianturco-the Rosch, Hanaro, Memotherm, and Wallstent-were used in this study. For evaluation of the physical properties of each, hoop strengths and changes in radii according to the degrees of longitudinal flexion were compared. Stent characteristics seen on MR images were evaluated by measuring magnetic torque and by comparing images obtained in the vascular phantom using SE T1TI, FSE T2WI, and FMPSPGR sequences. These images were analyzed with special emphasis on artifact size and the apparant shepe of the stent. Hoop strength was greatest in the Gianturco-Rosch stent, followed by the Memotherm, Hanaro, and Wallstent. When flexed in the longitudinal axis, the radius of the Hanaro and Memotherm stent decreased slightly as a larger flexion angle was applied. When this was 90 deg, however, the connection of the Gianturco-Rosch stent collapsed. In contrast, the radius of the Wallstent became larger as a larger flexion angle was applied. At the portal of the MR imaging unit, neither the Memotherm nor Wallstent showed deflection; except for a thin hyperintense rim at both ends, their images were excellent, and the lumina of these stents were also clearly seen. In contrast, the Gianturco-Rosch and Hanaro stent demonstrated large deflexion and showed a severe black-hole artifact. As a result, visualization of the stents themselves and their lumina was impossible. The Gianturco-Rosch stent showed greatrer hoop strength than the others. The Wallstent showed good longitudinal flexibility and was thought to be effective in tortuous vessels. For follow-up after placement, especially when the nonferromagnetic Memotherm and Wallstent are used, MR imaging appears to be safe and useful.=20.

An intriguing design concept to enhance the pulsatile fatigue life of self-expanding stents.

Science.gov (United States)

Hsiao, Hao-Ming; Yin, Ming-Ting

2014-02-01

Intravascular stenting has emerged as the primary treatment for vascular diseases and has received great attention from the medical community since its introduction two decades ago. The endovascular self-expanding stent is used to treat peripheral artery diseases; however, once implanted, these stents suffer from various cyclic motions caused by pulsatile blood pressure and daily activities. Due to this challenging environment, fatigue performance has become a critical issue for stent design. In this paper, a simple yet intriguing concept of stent design aimed at enhancing pulsatile fatigue life is investigated. The concept of this design is to shift the highly concentrated stresses/strains away from the crown and re-distribute them along the stress-free bar arm by tapering its strut width. Finite element models were developed to evaluate the mechanical integrity and pulsatile fatigue resistance of the stent to various loading conditions. Results show that the fatigue safety factor jumped to 2.5-3.0 times that of the standard stent with constant strut width. This is astonishing considering that the stent profile and scaffolding were not compromised. The findings of this paper provide an excellent approach to the optimization of future stent design to greatly improve stent fatigue performance.

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.

Intimal hyperplasia and vascular remodeling after everolimus-eluting and sirolimus-eluting stent implantation in diabetic patients the randomized diabetes and drug-eluting stent (DiabeDES) IV intravascular ultrasound trial

DEFF Research Database (Denmark)

Antonsen, Lisbeth; Maeng, Michael; Thayssen, Per

2013-01-01

OBJECTIVE: To evaluate the effects of the everolimus-eluting Xience™/Promus™ stent (EES) and the sirolimus-eluting Cypher™ stent (SES) on intimal hyperplasia (IH) in diabetic patients. BACKGROUND: Patients with diabetes mellitus have increased risk of in-stent restenosis after coronary stent...... implantation due to intimal hyperplasia (IH). METHODS: In a sub study of the Randomized Comparison of Everolimus-Eluting and Sirolimus-Eluting Stents in Patients Treated with Percutaneous Coronary Intervention (SORT OUT IV trial), serial intravascular ultrasound (IVUS) 10-month follow-up data were available...... in 88 patients, including 48 EES and 40 SES treated patients. IVUS endpoints included IH volume, in-stent % volume obstruction and changes in external elastic membrane (EEM) volume. RESULTS: Compared with the SES group, IH volume was increased in the EES group [median (interquartile range): 2.8 mm(3) (0...

Imaging after vascular gene therapy

International Nuclear Information System (INIS)

Manninen, Hannu I.; Yang, Xiaoming

2005-01-01

Targets for cardiovascular gene therapy currently include limiting restenosis after balloon angioplasty and stent placement, inhibiting vein bypass graft intimal hyperplasia/stenosis, therapeutic angiogenesis for cardiac and lower-limb ischemia, and prevention of thrombus formation. While catheter angiography is still standard method to follow-up vascular gene transfer, other modern imaging techniques, especially intravascular ultrasound (IVUS), magnetic resonance (MR), and positron emission tomography (PET) imaging provide complementary information about the therapeutic effect of vascular gene transfer in humans. Although molecular imaging of therapeutic gene expression in the vasculatures is still in its technical development phase, it has already offered basic medical science an extremely useful in vivo evaluation tool for non- or minimally invasive imaging of vascular gene therapy

Preliminary clinical application in the cranial internal carotid artery of covered stents specially designed for intracranial vasculature

International Nuclear Information System (INIS)

Li Minghua; Luo Qiyi; Fang Chun; Xie Zhiyong; Cheng Yingsheng; Gao Bulang; Li Yu; Zhang Beilei; Xie Jian; Wang Yongli

2007-01-01

Objective: To investigate the flexibility of both the covered stents specially designed for use in intracranial vasculature and the delivering system in passing through the bone tube and the physiological curves of the cranial internal carotid artery (CICA) to reach the targeted area, the performance (adherence) of the covered stents in occluding vascular wall diseases and the impact on the vascular branches of the covered segment. Methods: The covered stents specially designed for use in intracranial vasculature were used to treat 13 patients with CICA diseases using endovascular techniques. There were 4 huge pseudoaneurysms, 4 giant aneurysms, 3 small wide-necked aneurysms, 1 giant pseudoaneurysm with concurrent internal carotid cavernous fistula (CCF), and 1 CCF. Prior to the detachment of the covered stents, balloon occlusion test (BOT) of the internal carotid artery on the diseased side and whole-brain digital subtraction angiography (DSA) were performed in all the patients. Three to 16 months following procedure, DSA and clinical follow-ups were performed. Results: Thirteen patients all tolerated the BOT well with the DSA demonstrating well-opened anterior and posterior communicating arteries. The covered stents and the delivering systems all successfully passed CICA to reach the targeted diseased area, with the diseased segments of the internal carotid artery including C3-C4 in 4 cases, C4-C5 in 4 and C6-C7 in 5. Immediately following the detachment of the covered stents, DSA demonstrated that 7 aneurysms were completely occluded, 4 aneurysms had slight endoleak, and 1 CCF had markedly-decreased blood flow through the fistula. In the patient with concurrent pseudoaneurysm and CCF, the pseudoaneurysm disappeared and the blood flow through the fistula was markedly-reduced immediately following the stenting procedure. Apart from one patient with aneurysmal subarachnoid hemorrhage who died due to extensive vascular spasm on the 9th day following the stenting

'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.

Surveillance Duplex Ultrasonography of Stent Grafts for Popliteal Aneurysms.

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Pineda, Danielle M; Troutman, Douglas A; Dougherty, Matthew J; Calligaro, Keith D

2016-05-01

Stent grafts, also known as covered stents, have become an increasingly acceptable treatment for popliteal artery aneurysms. However, endovascular exclusion confers lower primary patency compared to traditional open bypass and exclusion. The purpose of this study was to evaluate whether duplex ultrasonography (DU) can reliably diagnose failing stent grafts placed for popliteal artery aneurysms prior to occlusion. Between June 5, 2007, and March 11, 2014, 21 stent grafts (Viabahn; Gore, Flagstaff, Arizona) were placed in 19 patients for popliteal artery aneurysms. All patients had at least 1 follow-up duplex scan postoperatively. Mean follow-up was 28.9 months (9-93 months). Postoperative DU surveillance was performed in our Intersocietal Accreditation Commission noninvasive vascular laboratory at 1 week postprocedure and every 6 months thereafter. Duplex ultrasonography measured peak systolic velocities (PSVs) and ratio of adjacent PSVs (Vr) every 5 cm within the stent graft and adjacent arteries. We retrospectively classified the following factors as "abnormal DU findings": focal PSV > 300 cm/s, uniform PSVs 3.0. These DU criteria were derived from laboratory-specific data that we previously published on failing stent grafts placed for lower extremity occlusive disease. Four of the 21 stent grafts presented with symptomatic graft thrombosis within 6 months of a normal DU. Three of these 4 patients presented with rest pain and underwent thrombectomy (2) or vein bypass (1), and 1 elected for nonintervention for claudication. Our results suggest that surveillance DU using criteria established for grafts placed for occlusive disease may not be useful for predicting stent graft failure in popliteal artery aneurysms. © The Author(s) 2016.

Frequency and Effect of Access-Related Vascular Injury and Subsequent Vascular Intervention After Transcatheter Aortic Valve Replacement

DEFF Research Database (Denmark)

Dencker, Ditte; Taudorf, Mikkel; Luk, N H Vincent

2016-01-01

patients underwent TAVR and 333 patients (94%) were treated by true percutaneous transfemoral approach. Of this latter group, 83 patients (25%) had an access-related vascular injury that was managed by the use of a covered self-expanding stent (n = 49), balloon angioplasty (n = 33), or by surgical...

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.

Animal experiment on 188Re-radioactive nanometre particle esophageal stent

International Nuclear Information System (INIS)

Chu Jianjun; Yang Bo; Zhao Difei; Wang Mingzhi; Sun Liang; Jiang Wei

2004-01-01

Objective: To investigate the mechanism and clinical reliability of applying 188 Re-radioactive nanometre particle esophageal stent. Methods: An elastic meshed esophageal stent made of double membranous nickel-titanium alloy and loaded with 188 Re-radioactive nanometre particles was used . The stent was introduced into the esophagus of eight experimental pigs and fixed in place. Two pigs served as controls. With the pig aneasthetized, the stent with good expandability was placed in the proper position. Radioactive MBq was applied to the 8 experiment pigs while the two control pigs received only the stent without the radioactive material. Three hours after the insertion of the stent, the pigs were allowed to feed, without any choking observed. Results: Seven days after the treatment of pathologic experiment pigs showed infla mmatory celluar infilfration, congestion and edema in the mucosa and submucous layer. After 21 days, some parts of the esophageal mucosa showed thickening of the vascular layer of the blood vessels and scanty fibrous hyperplasia. Seven days after application of larger dose of 259 MBq stent, pathology examination carried out in the experiment pigs showed extensive infla mmatory cellular infilfration, edema and congestion in the muscles and submucosa, and patch-like necrosis. Twenty-one days after application, repairing fibrous hyperplasia appeared. In the control pigs, not even any traumatic damage was observed. Periodic checking of the stool did not show any leakage of radioactivity and there was no displacement of the stents as confirmed by X-ray exam. Conclusions: The stent is effective to maintain an unobstructed passage of food . The loaded radioactive particles can be concentrated in the target area and adjusted by a body surface magnetic modulation and inhibit the intraluminal epithelial growth of esophageal mucosa without any severe radiation reaction or damage. It is quite promising to resolve the obstruction of advanced esophageal

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...

Infolding of fenestrated endovascular stent graft.

Science.gov (United States)

Zelt, Jason G E; Jetty, Prasad; Hadziomerovic, Adnan; Nagpal, Sudhir

2017-09-01

We report a case of infolding of a fenestrated stent graft involving the visceral vessel segment after a juxtarenal abdominal aorta aneurysm repair. The patient remains free of any significant endoleak, and the aortic sac has shown regression. The patient remains asymptomatic, with no abdominal pain, with normal renal function, and without ischemic limb complications. We hypothesize that significant graft oversizing (20%-30%) with asymmetric engineering of the diameter-reducing ties may have contributed to the infolding. Because of the patient's asymptomatic nature and general medical comorbidities, further intervention was deemed inappropriate as the aneurysmal sac is regressing despite the infolding.

Outcome of everolimus eluting bioabsorbable vascular scaffold (BVS) compared to non BVS drug eluting stent in the management of ST-segment elevation myocardial infarction (STEMI) — A comparative study

International Nuclear Information System (INIS)

Chakraborty, Rabin; Patra, Soumya; Banerjee, Suvro; Pande, Arindam; Khan, Aftab; Mandol, Prakash Chandra; Ghosh, Debashish; De, Swapan Kumar; Das, Sankha Subhro; Nag, Raja

2016-01-01

Background: The safety and efficacy of everolimus eluting bioabsorbable vascular scaffold (BVS) in the management of “ST” segment elevation myocardial infarction (STEMI) are yet to be established. Aims: To evaluate immediate and short term safety and efficacy of the everolimus-eluting ABSORB BVS compared with non BVS drug eluting stent (DES) in patients with STEMI. Methods: From December 2013 to December 2014, 220 patients with STEMI were included in this study. Among them, 35 patients treated with BVS were compared with a control group composed of 180 patients who underwent non BVS DES implantation in the same time period. The incidence of major adverse cardiac events (MACE: stent thrombosis: death, non-fatal myocardial infarction, or target vessel/lesion revascularization) before discharge and up to six months was evaluated. Results: 1 vessel disease was more frequent whereas, 2 and 3 vessel disease was less frequent in BVS group. Procedural characteristics were also similar between groups, except for the use of post dilation (p = 0.04). Procedural success, in-hospital, and up to six-month MACE rates were similar between both groups. Definite or probable stent thrombosis did not occur (according to the ARC criteria) in BVS patients, though two patients during the index admission and another two patients in the first month after DES implantation had stent thrombosis. Conclusion: The use of the ABSORB BVS for STEMI is feasible and associated with good procedural safety, and angiographic success rate.

Outcome of everolimus eluting bioabsorbable vascular scaffold (BVS) compared to non BVS drug eluting stent in the management of ST-segment elevation myocardial infarction (STEMI) — A comparative study

Energy Technology Data Exchange (ETDEWEB)

Chakraborty, Rabin; Patra, Soumya, E-mail: dr_soumyapatra@rediffmail.com; Banerjee, Suvro; Pande, Arindam; Khan, Aftab; Mandol, Prakash Chandra; Ghosh, Debashish; De, Swapan Kumar; Das, Sankha Subhro; Nag, Raja

2016-04-15

Background: The safety and efficacy of everolimus eluting bioabsorbable vascular scaffold (BVS) in the management of “ST” segment elevation myocardial infarction (STEMI) are yet to be established. Aims: To evaluate immediate and short term safety and efficacy of the everolimus-eluting ABSORB BVS compared with non BVS drug eluting stent (DES) in patients with STEMI. Methods: From December 2013 to December 2014, 220 patients with STEMI were included in this study. Among them, 35 patients treated with BVS were compared with a control group composed of 180 patients who underwent non BVS DES implantation in the same time period. The incidence of major adverse cardiac events (MACE: stent thrombosis: death, non-fatal myocardial infarction, or target vessel/lesion revascularization) before discharge and up to six months was evaluated. Results: 1 vessel disease was more frequent whereas, 2 and 3 vessel disease was less frequent in BVS group. Procedural characteristics were also similar between groups, except for the use of post dilation (p = 0.04). Procedural success, in-hospital, and up to six-month MACE rates were similar between both groups. Definite or probable stent thrombosis did not occur (according to the ARC criteria) in BVS patients, though two patients during the index admission and another two patients in the first month after DES implantation had stent thrombosis. Conclusion: The use of the ABSORB BVS for STEMI is feasible and associated with good procedural safety, and angiographic success rate.

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.)

Absorb bioresorbable vascular scaffold versus everolimus-eluting metallic stent in ST-segment elevation myocardial infarction: 1-year results of a propensity score matching comparison: the BVS-EXAMINATION Study (bioresorbable vascular scaffold-a clinical evaluation of everolimus eluting coronary stents in the treatment of patients with ST-segment elevation myocardial infarction).

Science.gov (United States)

Brugaletta, Salvatore; Gori, Tommaso; Low, Adrian F; Tousek, Petr; Pinar, Eduardo; Gomez-Lara, Josep; Scalone, Giancarla; Schulz, Eberhard; Chan, Mark Y; Kocka, Viktor; Hurtado, Jose; Gomez-Hospital, Juan Antoni; Münzel, Thomas; Lee, Chi-Hang; Cequier, Angel; Valdés, Mariano; Widimsky, Petr; Serruys, Patrick W; Sabaté, Manel

2015-01-01

The purpose of this study was to compare the 1-year outcome between bioresorbable vascular scaffold (BVS) and everolimus-eluting metallic stent (EES) in ST-segment elevation myocardial infarction (STEMI) patients. The Absorb BVS (Abbott Vascular, Santa Clara, California) is a polymeric scaffold approved for treatment of stable coronary lesions. Limited and not randomized data are available on its use in ST-segment elevation myocardial infarction (STEMI) patients. This study included 290 consecutive STEMI patients treated by BVS, compared with either 290 STEMI patients treated with EES or 290 STEMI patients treated with bare-metal stents (BMS) from the EXAMINATION (A Clinical Evaluation of Everolimus Eluting Coronary Stents in the Treatment of Patients With ST-segment Elevation Myocardial Infarction) trial, by applying propensity score matching. The primary endpoint was a device-oriented endpoint (DOCE), including cardiac death, target vessel myocardial infarction, and target lesion revascularization, at 1-year follow-up. Device thrombosis, according to the Academic Research Consortium criteria, was also evaluated. The cumulative incidence of DOCE did not differ between the BVS and EES or BMS groups either at 30 days (3.1% vs. 2.4%, hazard ratio [HR]: 1.31 [95% confidence interval (CI): 0.48 to 3.52], p = 0.593; vs. 2.8%, HR: 1.15 [95% CI: 0.44 to 2.30], p = 0.776, respectively) or at 1 year (4.1% vs. 4.1%, HR: 0.99 [95% CI: 0.23 to 4.32], p = 0.994; vs. 5.9%, HR: 0.50 [95% CI: 0.13 to 1.88], p = 0.306, respectively). Definite/probable BVS thrombosis rate was numerically higher either at 30 days (2.1% vs. 0.3%, p = 0.059; vs. 1.0%, p = 0.324, respectively) or at 1 year (2.4% vs. 1.4%, p = 0.948; vs. 1.7%, p = 0.825, respectively), as compared with EES or BMS. At 1-year follow-up, STEMI patients treated with BVS showed similar rates of DOCE compared with STEMI patients treated with EES or BMS, although rate of scaffolds thrombosis, mostly clustered in the early phase

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

Science.gov (United States)

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

2017-06-01

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

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

Science.gov (United States)

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

2012-01-01

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

Comparison of Immediate and 2-Year Outcomes between Excimer Laser-Assisted Angioplasty with Spot Stent and Primary Stenting in Intermediate to Long Femoropopliteal Disease

Directory of Open Access Journals (Sweden)

Tien-Yu Wu

2013-01-01

Full Text Available Background. To compare the clinical outcomes between excimer laser-assisted angioplasty (ELA with spot stent (group A and primary stenting (group B in intermediate to long femoropopliteal disease. Methods. Outcomes of 105 patients totaling 119 legs treated with two different strategies were analyzed retrospectively in a prospectively maintained database. Results. Baseline characteristics were similar in both groups. Better angiographic results and lesser increase of serum C-reactive protein levels (0.60 ± 0.72 versus 2.98 ± 0.97 mg/dL, P<0.001 after the intervention were obtained in Group B. Group A had inferior 1-year outcomes due to higher rate of binary restenosis (67% versus 32%, P=0.001 and lower rate of primary patency (40% versus 58%, P=0.039. Rates of amputation-free survival, target vessel revascularization, assisted primary patency, and stent fracture at 24 months were similar in both groups (80% versus 82%, P=0.979, 65% versus 45%, P=0.11, 78% versus 80%, P=0.75 and 6.3% versus 6.8%, P=0.71, resp.. Conclusion. Greater vascular inflammation after ELA with spot stent resulted in earlier restenosis and inferior 1-year clinical outcomes than primary stenting. This benefit was lost in the primary stenting group at 2 years due to late catch-up restenosis. Active surveillance with prompt intervention was required to maintain the vessel patency.

Composite self-expanding bioresorbable prototype stents with reinforced compression performance for congenital heart disease application: Computational and experimental investigation.

Science.gov (United States)

Zhao, Fan; Xue, Wen; Wang, Fujun; Liu, Laijun; Shi, Haoqin; Wang, Lu

2018-08-01

Stents are vital devices to treat vascular stenosis in pediatric patients with congenital heart disease. Bioresorbable stents (BRSs) have been applied to reduce challenging complications caused by permanent metal stents. However, it remains almost a total lack of BRSs with satisfactory compression performance specifically for children with congenital heart disease, leading to importantly suboptimal effects. In this work, composite bioresorbable prototype stents with superior compression resistance were designed by braiding and annealing technology, incorporating poly (p-dioxanone) (PPDO) monofilaments and polycaprolactone (PCL) multifilament. Stent prototype compression properties were investigated. The results revealed that novel composite prototype stents showed superior compression force compared to the control ones, as well as recovery ability. Furthermore, deformation mechanisms were analyzed by computational simulation, which revealed bonded interlacing points among yarns play an important role. This research presents important clinical implications in bioresorbable stent manufacture and provides further study with an innovative stent design. Copyright © 2018 Elsevier Ltd. All rights reserved.

Outcomes for cervicomediastinal vascular trauma managed by a ...

African Journals Online (AJOL)

Management was multimodal, and included conservative (8%), stenting and embolisation (8%), referral to a higher centre (8%), vascular repair (64%) and ligation (12%). Nineteen per cent required median sternotomy or thoracotomy. Eight patients died postoperatively (9%). Seven of them presented in extremis and died ...

Hemodynamic comparison of stent configurations used for aortoiliac occlusive disease.

Science.gov (United States)

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

2017-07-01

. The CERAB configuration is the most unimpaired physiologic reconstruction, whereas BMK and CK stents have their typical zones of flow recirculation. Copyright © 2016 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

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

Science.gov (United States)

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

1992-04-01

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

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)

Percutaneous Endoluminal Stent-Graft Repair of an Old Traumatic Femoral Arteriovenous Fistula

International Nuclear Information System (INIS)

Uflacker, Renan; Elliott, Bruce M.

1996-01-01

A stent-graft was custom made to close a high-flow traumatic arteriovenous fistula of the left superficial femoral artery, present for 30 years, in a 60-year-old man with congestive heart failure and ischemic ulceration in the left foot. A balloon expandable Palmaz stent (P394; 2.5 mm x 3.9 cm) was covered with a polytetrafluoroethylene (PTFE) graft and was inserted percutaneously through an 11 Fr vascular sheath. Follow-up Doppler ultrasound at 6 months demonstrated occlusion of the arteriovenous fistula, patency of the artery, and luminal integrity of the artery and vein

A randomized multicenter comparison of hybrid sirolimus-eluting stents with bioresorbable polymer versus everolimus-eluting stents with durable polymer in total coronary occlusion: rationale and design of the Primary Stenting of Occluded Native Coronary Arteries IV study

Directory of Open Access Journals (Sweden)

Teeuwen Koen

2012-12-01

Full Text Available Abstract Background Percutaneous recanalization of total coronary occlusion (TCO was historically hampered by high rates of restenosis and reocclusions. The PRISON II trial demonstrated a significant restenosis reduction in patients treated with sirolimus-eluting stents compared with bare metal stents for TCO. Similar reductions in restenosis were observed with the second-generation zotarolimus-eluting stent and everolimus-eluting stent. Despite favorable anti-restenotic efficacy, safety concerns evolved after identifying an increased rate of very late stent thrombosis (VLST with drug-eluting stents (DES for the treatment of TCO. Late malapposition caused by hypersensitivity reactions and chronic inflammation was suggested as a probable cause of these VLST. New DES with bioresorbable polymer coatings were developed to address these safety concerns. No randomized trials have evaluated the efficacy and safety of the new-generation DES with bioresorbable polymers in patients treated for TCO. Methods/Design The prospective, randomized, single-blinded, multicenter, non-inferiority PRISON IV trial was designed to evaluate the safety, efficacy, and angiographic outcome of hybrid sirolimus-eluting stents with bioresorbable polymers (Orsiro; Biotronik, Berlin, Germany compared with everolimus-eluting stents with durable polymers (Xience Prime/Xpedition; Abbott Vascular, Santa Clara, CA, USA in patients with successfully recanalized TCOs. In total, 330 patients have been randomly allocated to each treatment arm. Patients are eligible with estimated duration of TCO ≥4 weeks with evidence of ischemia in the supply area of the TCO. The primary endpoint is in-segment late luminal loss at 9-month follow-up angiography. Secondary angiographic endpoints include in-stent late luminal loss, minimal luminal diameter, percentage of diameter stenosis, in-stent and in-segment binary restenosis and reocclusions at 9-month follow-up. Additionally, optical coherence

Capture of circulatory endothelial progenitor cells and accelerated re-endothelialization of a bio-engineered stent in human ex vivo shunt and rabbit denudation model

NARCIS (Netherlands)

K. Larsen (Katarína); C. Cheng (Caroline (Ka Lai)); D. Tempel (Dennie); S. Parker (Sherry); S. Yazdani (Saami); W.K. den Dekker (Wijnand); H.J. Houtgraaf (Jaco); R. de Jong (Renate); S. Swager-ten Hoor (Stijn); E. Ligtenberg (Erik); S.R. Hanson (Stephen); R. Rowland (Steve); F. Kolodgie (Frank); P.W.J.C. Serruys (Patrick); R. Virmani (Renu); H.J. Duckers (Henricus)

2012-01-01

textabstractThe Genous™ Bio-engineered R™ stent (GS) aims to promote vascular healing by capture of circulatory endothelial progenitor cells (EPCs) to the surface of the stent struts, resulting in accelerated re-endothelialization. Here, we assessed the function of the GS in comparison to bare-metal

Predictors for adverse outcome after iliac angioplasty and stenting for limb-threatening ischemia.

Science.gov (United States)

Timaran, Carlos H; Stevens, Scott L; Freeman, Michael B; Goldman, Mitchell H

2002-09-01

The role of iliac artery angioplasty and stenting (IAS) for the treatment of limb-threatening ischemia is not defined. IAS has been used primarily for patients with disabling claudication. Because poorer results have been shown in patients with critical ischemia after iliac artery angioplasty, the purpose of this study was to estimate the influence of risk factors on the outcome of iliac angioplasty and stent placement in patients with limb-threatening ischemia. During a 5-year period (from 1996 to 2001), 85 iliac angioplasty and stent placement procedures (107 stents) were performed in 31 women and 43 men with limb-threatening ischemia. Patients with claudication were specifically excluded. The criteria prepared by the Ad Hoc Committee on Reporting Standards (Society for Vascular Surgery/International Society for Cardiovascular Surgery) were followed to define the variables. The TransAtlantic InterSociety Consensus classification was used to characterize the type of iliac lesions. Both univariate (Kaplan-Meier [KM]) and multivariate analyses (Cox proportional hazards model) were used to determine the association between variables, cumulative patency, limb salvage, and survival. Indications for iliac angioplasty with stenting were ischemic rest pain (56%) and tissue loss (44%). Primary stenting was performed in 36 patients (42%). Stents were placed selectively after iliac angioplasty mainly for residual stenosis or pressure gradient (43%). Overall, primary stent patency rate was 90% at 1 year, 74% at 3 years, and 69% at 5 years. Primary stent patency rate was significantly reduced in women compared with men (KM, log-rank test, P 1.6 mg/dL; KM, log-rank test, P IAS. Limb salvage, as shown in this study, is not affected by previous iliac stent failure.

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

Vascular Complications of Pancreatitis: Role of Interventional Therapy

Energy Technology Data Exchange (ETDEWEB)

Barge, Jaideep U.; Lopera, Jorge E. [University of Texas Health Science Center, San Antonio (United States)

2012-02-15

Major vascular complications related to pancreatitis can cause life-threatening hemorrhage and have to be dealt with as an emergency, utilizing a multidisciplinary approach of angiography, endoscopy or surgery. These may occur secondary to direct vascular injuries, which result in the formation of splanchnic pseudoaneurysms, gastrointestinal etiologies such as peptic ulcer disease and gastroesophageal varices, and post-operative bleeding related to pancreatic surgery. In this review article, we discuss the pathophysiologic mechanisms, diagnostic modalities, and treatment of pancreatic vascular complications, with a focus on the role of minimally-invasive interventional therapies such as angioembolization, endovascular stenting, and ultrasound-guided percutaneous thrombin injection in their management.

Atrial fibrillation and vascular disease-a bad combination

DEFF Research Database (Denmark)

Bjerring Olesen, Jonas; Gislason, Gunnar Hilmar; Torp-Pedersen, Christian

2012-01-01

This article provides an overview of (i) the risk of stroke associated with vascular disease (acute coronary syndromes and peripheral artery disease) in patients with atrial fibrillation, (ii) the frequent coexistence of vascular disease in patients with atrial fibrillation and, (iii...... fibrillation. Indeed, patients with atrial fibrillation often had coexisting vascular disease (around 18%), and the combination of the two diseases substantially increases the risk of future cardiovascular events. The increased risk associated with peripheral artery disease in atrial fibrillation is even more...... pronounced. Patients with atrial fibrillation and stable vascular disease should be treated with oral anticoagulation only, although when these patients present with acute coronary syndrome and/or undergo coronary stenting, concomitant treatment with antiplatelet drugs is indicated. To guide antithrombotic...

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....

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

International Nuclear Information System (INIS)

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

2006-01-01

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

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.

Bilateral spontaneous internal carotid artery dissection managed with endovascular stenting – A case report

Directory of Open Access Journals (Sweden)

Manoj Kumar Agarwala

2016-09-01

We describe a patient with ischemic stroke from spontaneous bilateral ICAD with completely occluded left ICA. Having failed medical therapy with antiplatelets and anticoagulants due to extensive loss of carotid vascular supply, he was managed successfully with endovascular stenting with good neurological recovery.

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.

Utility of Covered Stents for Revision of Aging Failing Synthetic Hemodialysis Grafts: A Report of Three Cases

International Nuclear Information System (INIS)

Silas, Anne M.; Bettmann, Michael A.

2003-01-01

Three aging failing hemodialysis polytetrafluoroethylene bypass shunts, average age 44 months, previously percutaneously revised with balloon angioplasty, presented with pseudoaneurysms and recurrent thrombosis. All were treated with percutaneous covered stent placement within their affected limbs. One graft was ligated 1 month after treatment for infected overlying skin ulcer, though this graft was subsequently surgically revised with interposition graft and the covered stent portion remains functional at 19 month follow-up. The 18- and 13- month follow- up of the remaining 2 patients shows that the covered stents remained patent and they are functional and being successfully and routinely punctured for dialysis. In this elderly population, the use of covered stents may prolong the functional life of failing hemodialysis bypass grafts, reducing the number of percutaneous and surgical interventions and further sparing other vascular access sites

Vascular tissue reaction to acute malapposition in human coronary arteries sequential assessment with optical coherence tomography

NARCIS (Netherlands)

J.L. Gutiérrez-Chico; J.J. Wykrzykowska (Joanna); E. Nüesch (Eveline); R.J.M. van Geuns (Robert Jan); K. Koch (Karel); J.J. Koolen (Jacques); C. di Mario (Carlo); S.W. Windecker (Stephan); G.A. van Es (Gerrit Anne); P. Gobbens (Pierre); P. Jüni (Peter); E.S. Regar (Eveline); P.W.J.C. Serruys (Patrick)

2012-01-01

textabstractBackground-The vascular tissue reaction to acute incomplete stent apposition (ISA) is not well known. The aim of this study was to characterize the vascular response to acute ISA in vivo and to look for predictors of incomplete healing. Methods and Results-Optical coherence tomography

Experimental study on effect of dexamethasone to the in-stent restenosis after vascular intervention

International Nuclear Information System (INIS)

Wang Jianbo; Yang Jianyong; Chen Wei; Zhuang Wenquan; Li Jiaping; Zhang Longjuan

2007-01-01

Objective: To evaluate the effect of dexamethasone to the cultured rat thoracic aortic smooth muscle cells (SMC) in vitro, and explore the role on it's prevention and cure for the in-stent restenosis after vascular intervention. Methods: The rat thoracic aortic SMC were harvested and cultured for six to ten passages. The cultured SMC were synchronized and then restimutated to enter the cell cycle, and treated with incremental concentrations of dexamethasone or without dexamethasone as control. The proliferative assay was performed with MTT method in the different time points after treatment. RT-PCR was performed to assay the level of proliferating cell nuclear antigen (PCNA) mRNA. Results: 1. Dexamethasone progressively inhibited rat aortic SMC proliferation in a concentration-dependent fashion. The A value was statistically significant for different concentrations (F=36.02, P -6 and 10 -5 mol/L (P=0.065) or between 10 -11 mol/L and control group (P 0.567). 2. RT-PCR suggested dexamethasone significantly decreased rat aortic SMC PCNA mRNA transcription in a concentration-dependent fashion. Statistical analysis indicated F=15.407 and P -9 or 10 -11 mol/L groups by post hoc analysis. Conclusions: Dexamethasone inhibits rat aortic SMC proliferation in a concentration- dependent fashion. The data suggest that effective action concentration is 10 -7 mol/L with persistent time up to 96 hours or more. Dexamethasone may play the inhibit role to SMC at lower concentration with prolonging action time. (authors)

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.

Successful technical and clinical outcome using a second generation balloon expandable coronary stent for transplant renal artery stenosis: Our experience.

Science.gov (United States)

Salsamendi, Jason; Pereira, Keith; Baker, Reginald; Bhatia, Shivank S; Narayanan, Govindarajan

2015-10-01

Transplant renal artery stenosis (TRAS) is a vascular complication frequently seen because of increase in the number of renal transplantations. Early diagnosis and management is essential to optimize a proper graft function. Currently, the endovascular treatment of TRAS using angioplasty and/or stenting is considered the treatment of choice with the advantage that it does not preclude subsequent surgical correction. Treatment of TRAS with the use of stents, particularly in tortuous transplant renal anatomy presents a unique challenge to an interventional radiologist. In this study, we present three cases from our practice highlighting the use of a balloon-expandable Multi-Link RX Ultra coronary stent system (Abbott Laboratories, Abbott Park, Illinois, USA) for treating high grade focal stenosis along very tortuous renal arterial segments. Cobalt-Chromium alloy stent scaffold provides excellent radial force, whereas the flexible stent design conforms to the vessel course allowing for optimal stent alignment.

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.

Feasibility study for the investigation of Nitinol self-expanding stents by neutron techniques

International Nuclear Information System (INIS)

Rogante, M.; Pasquini, U.; Rosta, L.; Lebedev, V.

2011-01-01

In this paper, neutron techniques - in particular, small angle neutron scattering (SANS) and neutron diffraction (ND) - are considered for the non-destructive characterization of Nitinol artery stents. This roughly equiatomic (50Ni-50Ti at%) shape memory alloy (SMA) exhibits significant properties of superelasticity and biocompatibility that make it suitable to be typically used as smart material for medical implants and devices. Nitinol self-expanding artery stents, as permanent vascular support structures, supply an ideal option to bypass surgery, but they are submitted for the whole of patient's life to the dynamical stress of the artery pulsation and the aggression from the biological environment. These stents, consequently, can suffer from wear and fracture occurrence likely due to a variety of cyclic fatigue, overload conditions and residual stresses. Neutrons have recently become a progressively more important probe for various materials and components and they allow achieving information complementary to those obtained from the traditional microstructural analyses. The outputs from the preliminary works already carried out in this field consent to consider neutron techniques capable to contribute to the development of these crucial medical implants. The achievable results can yield trends adoptable in monitoring of the stent features. -- Research Highlights: → Neutron techniques can contribute to develop Nitinol self-expanding artery stents. → Neutrons investigations can help avoiding wear and fracture events in Nitinol stents. → Neutron techniques can yield trends adoptable in monitoring of Nitinol stent features. → SANS is able to perform a micro- and nano-scale characterization of Nitinol stents. → Neutron Diffraction helps assessing stresses due to the exercise in Nitinol stents.

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.

Effect of longitudinal anatomical mismatch of stenting on the mechanical environment in human carotid artery with atherosclerotic plaques.

Science.gov (United States)

Fan, Zhenmin; Liu, Xiao; Sun, Anqiang; Zhang, Nan; Fan, Zhanming; Fan, Yubo; Deng, Xiaoyan

2017-10-01

Longitudinal anatomic mismatch (LAM) of stenting (i.e., a stenotic artery segment is not fully covered by a deployed stent) worsens the mechanical environment in the treated artery, which most likely is the cause for the associated high risks of restenosis, myocardial infarction and stent thrombosis. To probe the possibility, we constructed a patient-specific carotid model with two components of plaques (lipid and calcified plaque) based on MRI images; we numerically compared three different stenting scenarios in terms of von Mises stress (VMS) distribution in the treated arteries, namely, the short stenting (LAM), the medium stenting and the long stenting. The results showed that the short stenting led to more areas with abnormally high VMS along the inner surface of the treated artery with a much higher surface-averaged VMS at the distal end of the stent than both the medium and long stenting. While the VMS distribution in the calcified plaques was similar for the three stenting models, it was quite different in the lipid plaques among the three stenting models. The lipid plaque of the short-stent model showed more volume of the lipid plaque subjected to high VMS than those of the other two models. Based on the obtained results, we may infer that the short stenting (i.e., LAM) may aggravate vascular injury due to high VMS on the artery-stent interaction surface and within the lipid plaque. Therefore, to obtain a better outcome, a longer stent, rather than a short one, might be needed for arterial stenting. Copyright © 2017 IPEM. Published by Elsevier Ltd. All rights reserved.

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).

Use of Self-Expanding Stents for the Treatment of Vertebral Artery Ostial Stenosis: a Single Center Experience

International Nuclear Information System (INIS)

Chung, Sun Young; Lee, Deok Hee; Choi, Jin Woo; Choi, Byung Se; In, Hyun Sin; Kim, Sun Mi; Choi, Choong Gon; Kim, Sang Joon; Suh, Dae Chul

2010-01-01

To evaluate our early experience using self-expanding stents to treat atherosclerotic vertebral artery ostial stenosis (VAOS), with respect to technical feasibility and clinical and imaging follow-up results. A total of 20 lesions in 20 patients underwent stenting of the VAOS using a self-expanding stent (Precise RX; Cordis Neurovascular, Miami Lakes, FL). Two patients were asymptomatic. We analyzed the technical success rate, causes of technical failure, occurrence of any vascular or neurological event, and the occurrence of any neurological abnormality or in-stent restenosis (ISR) seen on follow-up. The imaging follow-up was performed with Doppler ultrasound (DUS) as a primary screening modality. One instance of technical failure was caused by failure of the guidewire passage. The stent diameter was 5 mm, and post-stenting balloon dilatations were necessary in all cases. Stent misplacement requiring placement of an additional stent occurred in four cases. Following a 14.8 month average clinical follow-up time, two patients showed anterior circulation ischemia, which was not attributed to the VAOS we treated. Following a 13.7 month average DUS follow-up, five patients showed a mild degree of diffuse or focal intimal thickening in the stent lumen; however, none of the stenosis showed luminal loss of more than 50% and no stent fracture was noted. The use of self-expanding stents for treating VAOS was technically feasible and helped to improve artery patency during our limited follow-up interval

Vascular Tissue Reaction to Acute Malapposition in Human Coronary Arteries Sequential Assessment With Optical Coherence Tomography

NARCIS (Netherlands)

Gutiérrez-Chico, Juan Luis; Wykrzykowska, Joanna; Nüesch, Eveline; van Geuns, Robert Jan; Koch, Karel T.; Koolen, Jacques J.; Di Mario, Carlo; Windecker, Stephan; van Es, Gerrit-Anne; Gobbens, Pierre; Jüni, Peter; Regar, Evelyn; Serruys, Patrick W.

2012-01-01

Background-The vascular tissue reaction to acute incomplete stent apposition (ISA) is not well known. The aim of this study was to characterize the vascular response to acute ISA in vivo and to look for predictors of incomplete healing. Methods and Results-Optical coherence tomography studies of 66

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

Rotational and aspiration atherectomy for infrainguinal in-stent restenosis.

Science.gov (United States)

Beschorner, Ulrich; Krankenberg, Hans; Scheinert, Dierk; Sievert, Horst; Tübler, Thilo; Sixt, Sebastian; Noory, Elias; Rastan, Aljoscha; Macharzina, Roland; Zeller, Thomas

2013-03-01

To report feasibility and safety of the Pathway PV™ Atherectomy System during percutaneous peripheral vascular interventions of in-stent restenosis. 33 patients (66.7 % men; mean age 68.7 years; 39.4 % diabetics) with symptomatic infrainguinal in-stent restenosis were enrolled at 5 study sites. Primary study endpoint was the 30-day serious adverse event (SAE) rate. At one study site a subgroup of 13 patients was scheduled for additional follow-up examinations with duplex. Forty lesions with a mean lesion length of 85.7 mm (range 6 - 370 mm) were treated including total occlusions (20 %) and infrapopliteal lesions (5 %). In sixteen target lesions (40 %) procedural success was reached with atherectomy alone, 23 lesions (57.5 %) received adjunctive percutaneous transluminal angioplasty to obtain a sufficient angiographic result. Freedom from device-related SAEs was 100 %. Overall there were 11 unexpected adverse events in 11 patients, two of which were serious (retroperitoneal bleeding and access site infection). The ankle-brachial index increased significantly from 0.65 ± 0.13 at baseline to 0.82 ± 0.15 at 30 days. Mean Rutherford category improved from 2.8 ± 0.7 at baseline to 1.0 ± 1.2. In the subgroup with longer follow- up primary patency was 33 % after 12 months and 25 % after 24 months. Secondary patency was 92 % after 12 and 24 months. The use of the Pathway PV™ System during percutaneous peripheral vascular interventions of in-stent restenosis appears to be feasible and safe but does not seem to offer a sustainable solution regarding long term patency. A combination with drug eluting balloon angioplasty could be an interesting option and should be evaluated in further clinical trials.

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...

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

Science.gov (United States)

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

2004-05-01

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

The implantation of separating aortic stent-graft into the canine thoracic aorta: an experimental study

International Nuclear Information System (INIS)

Xia Jinguo; Shi Haibin; Yang Zhengqiang; Li Chao; Liu Sheng; Zu Qingquan; Li Linsun

2011-01-01

Objective: to assess the technical feasibility of implanting separating stent-graft into the canine thoracic aorta and to study its biocompatibility. Methods: Twelve adult dogs were randomly and equally divided into three groups. The right femoral artery was cut open, through which the separating stent-graft was inserted and deployed in the canine thoracic aorta, with the proximal end of the graft being quite close to the origin of the left subclavian artery. the technical feasibility of the deployment process was assessed. Angiography was performed at 4, 8 and 12 weeks after stent-graft placement to evaluate the position and patency of the stent-graft. Then the dogs were sacrificed and the specimens were collected for pathologic study. Both gross and microscopic examinations were made to evaluate the fixation of the stent-graft with the vessel wall, the endothelialization of stent-graft surface and the pathologic changes of the vascular wall. Results: A total of ten separating stent-grafts were successfully deployed in the canine thoracic aorta, no migration or deformation occurred. One dog died of massive bleeding due to the rupture of the right femoral artery which occurred when the delivery system containing the inner bare stent was inserted through the right femoral artery. Death occurred in another dog as a result of the ascending aorta rupture caused by the migration of outer-layer stent-graft. Angiography was conducted at 4, 8 and 12 weeks after stent-graft placement. No migration, deformation, rupture or stenosis of the implanted stent-grafts were observed. The formation of intima on the inner surface of the bare stent appeared at 4 weeks, which became more and more obvious with the time passing, and at 12 weeks complete endothelialization of stent-graft surface was observed. Conclusion: Technically, it is feasible to deploy the separating aortic stent-graft into the canine thoracic aorta. Moreover, the separating aortic stent-graft carries excellent

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.

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 degradation and transport mechanism of a Mg-Nd-Zn-Zr stent in rabbit common carotid artery: A 20-month study.

Science.gov (United States)

Zhang, Jian; Li, Haiyan; Wang, Wu; Huang, Hua; Pei, Jia; Qu, Haiyun; Yuan, Guangyin; Li, Yongdong

2018-03-15

Mg-based stent is a promising candidate of the next generation fully degradable vascular stents. The latest progress includes the CE approval of the Magmaris ® WE43 based drug eluting stent. However, so far, the long term (more than 1 year implantation) in vivo degradation and the physiological effects caused by the degradation products were still unclear. In this study, a 20 month observation was carried out after the bare Mg-Nd-Zn-Zr (abbr. JDBM) stent prototype was implanted into the common carotid artery of New Zealand white rabbit in order to evaluate its safety, efficacy and especially degradation behavior. The degradation of the main second phase Mg 12 Nd was also studied. Results showed that the bare JDBM stent had good safety and efficacy with a complete re-endothelialization within 28 days. The JDBM stent struts were mostly replaced in situ by degradation products in 4 month. The important finding was that the volume and Ca concentration of the degradation products decreased in the long term, eliminating the clinicians' concern of possible vessel calcification. In addition, the alloying elements Mg and Zn in the stent could be safely metabolized as continuous enrichment in any of the main organs were not detected although Nd and Zr showed an abrupt increase in spleen and liver after 1 month implantation. Collectively, the long term in vivo results showed the rapid re-endothelialization of JDBM stent and the long term safety of the degradation products, indicating its great potential as the backbone of the fully degradable vascular stent. Mg-based stent is a promising candidate of the next generation fully degradable stents, especially after the recent market launch of one of its kind (Magmaris). However the fundamental question about the long term degradation and metabolic mechanism of Mg-based stent and its degradation products remain unanswered. We implanted our patented Mg-Nd-Zn-Zr bare stent into the common carotid artery of rabbits and

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.

Extra-anatomic bypass for recurrent abdominal aortic and renal in-stent stenoses following radiotherapy for neuroblastoma.

Science.gov (United States)

Luehr, Maximilian; Siepe, Matthias; Beyersdorf, Friedhelm; Schlensak, Christian

2009-04-01

We describe the case of an 11-year-old girl with an abdominal neuroblastoma which was operated and intraoperatively irradiated nine years ago. After six years, she developed stenoses of the infrarenal abdominal aorta and both renal arteries. Initial treatment of the stenosed vessels comprised endovascular balloon dilatations and repeated stent-graft implantations, including drug eluting stents. However, severe in-stent stenoses occurred during follow-up and the girl developed acute renal failure. Open surgery was performed with two extra-anatomic bypasses, a thoracic-to-abdominal aortic bypass and a left iliac-to-renal bypass, on an urgent basis. The postoperative course was uneventful and the patient was discharged home two weeks after the operation with full recovery of renal function. We conclude that endovascular stent-graft placement in children can only be a palliative treatment due to outgrowing of the stent-graft and the potential risk of re-stenosis, especially after a history of irradiation. Vascular surgery with placement of extra-anatomic bypasses will provide a definite treatment.

Enterprise stent for the treatment of symptomatic intracranial atherosclerotic stenosis: an initial experience of 44 patients.

Science.gov (United States)

Feng, Zhengzhe; Duan, Guoli; Zhang, Ping; Chen, Lei; Xu, Yi; Hong, Bo; Zhao, Wenyuan; Liu, Jianmin; Huang, Qinghai

2015-10-08

Wingspan stenting for the treatment of complex intracranial atherosclerotic stenosis (ICAS), i.e., that involving tortuous vascular pathways, long (>15 mm) lesions or arterial bifurcations, has a relatively high risk of complications. This retrospective study assessed the safety and efficacy of undersized balloon angioplasty followed by deployment of the more flexible Enterprise stent for the treatment of complex symptomatic ICAS. Forty-four patients on combined antiplatelet therapy and intensive risk factor management and a symptomatic 70-99% stenosis of a major intracranial artery in complex settings that was treated with balloon angioplasty and Enterprise stent deployment between July 2009 and August 2013 were enrolled. Primary outcome was occurrence of ischemic or hemorrhagic stroke or death within 30 days after intervention. Secondary outcomes included procedural success (defined as achievement of 50% in-stent restenosis after mean 22 months follow-up. In this retrospective, single-center experience, undersized balloon angioplasty followed by Enterprise stent deployment appears technically feasible with a relatively low rate of complications for the treatment of complex symptomatic ICAS. Prospective, multicenter, randomized controlled trials against optimal medical management are warranted.

Outcome of endovascular treatment in symptomatic intracranial vascular stenosis

Energy Technology Data Exchange (ETDEWEB)

Suh, Dae Chul; Kim, Sang Joon; Lee, Duk Hee; Kim, Won; Choi, Choong Gon; Lee, Jeong Hyun; Kwon, Sun Uck; Kim, Jong Sung [Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of); Kim, Hyun Jeong [Daejeon Catholic Hospital, Daejeon (Korea, Republic of)

2005-03-15

The outcome evaluation for the revascularization of intracranial vascular stenoses has not been fully described due to the highly technical nature of the procedure. We report here on the early and late clinical outcome of angioplasty and/or stenting of symptomatic severe intracranial vascular stenoses at a single institute. Since 1995, we have treated 35 patients with symptomatic intracranial vascular stenosis (more than 70% stenosis, mean stenosis: 78.6% {+-} 6.2%). Angioplasty (n = 19) was performed for the horizontal segment of the middle cerebral artery (M1) (n = 16) and the basilar artery (BA) (n = 1), the intradural vertebral artery (VA) (n = 1), and the cavernous internal carotid artery (ICA) (n = 1). Stenting (n = 16) was performed for the cavernous or petrous ICAs (n = 9), the intradural VA (n = 3), BA (n = 2), and M1 (n = 2) artery. We assessed the angiographic success (defined as residual stenosis < 50%) rate, the periprocedural complications during the 30-day periprocedural period, the symptomatic recurrence and restenosis during a mean 22-month follow-up (FU) period. The Kaplan-Meier estimate of the cumulative even-free rate of the major cerebrovascular events, i.e. death, stroke or restenosis, was also done. Angiographic success was achieved in 97% of our patients (34/35). There were four procedure-related complications (11%) including a death and a minor stroke. During the mean 22-month FU, the asymptomatic restenosis rate was 9% and the symptomatic restenosis rate was 6% in the target lesion and 9% in all the vascular territories. The Kaplan-Meier estimate was 70.6% (95% confidence interval = 46.5-94.7) after 33 month of FU. In addition to a high angiographic success rate and an acceptable periprocedural complication rate, intracranial angioplasty and/or stenting revealed a relatively low symptomatic recurrence rate. Hemorrhage is a rare, but the physician must aware that potentially fatal periprocedural complications can occur.

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

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

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.

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.

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.

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.

Author disclosure of conflict of interest in vascular surgery journals.

Science.gov (United States)

Forbes, Thomas L

2011-09-01

Advances in vascular surgery are increasingly technology-driven, and the relationships between surgeons and the medical device industry can be complex. This study reviewed conflict of interest (COI) disclosure in the vascular surgery journals regarding several selected technology-driven topics, including endovascular stent grafts (EV), carotid artery stenting (CAS), and peripheral arterial interventions (PI), to suggest further directions. Authors' COI disclosures were reviewed from all clinical papers published in 2008 and 2009 in each of six vascular surgery journals, and pertaining to three selected topics (EV, CAS, and PI). Rate of COI disclosure was evaluated as a function of journal, topic, article type (randomized trial, case series, case report, review, or meta-analysis), and authors' region of origin. Secondarily, consistency of authors' disclosure was evaluated by reviewing papers by the same author and of the same topic. Six hundred thirty-five papers were reviewed from the six journals. A COI was declared in 125 (19.7%) of these papers. This rate differed between journals (range, 3.2%-34.1%; P journals (46.9%), or in the same journal (25%). Rates of disclosure of COI, and inconsistencies in disclosure in the vascular surgery literature are at least partially due to differences in journals' reporting policies, while a smaller proportion of these inconsistencies are due to individual author behavior. Journals should adopt a consistent requirement for a separate COI declaration where all relevant financial arrangements are disclosed. Copyright © 2011 Society for Vascular Surgery. Published by Mosby, Inc. All rights reserved.

A Mechanobiological model for damage-induced growth in arterial tissue with application to in-stent restenosis

Science.gov (United States)

Fereidoonnezhad, B.; Naghdabadi, R.; Sohrabpour, S.; Holzapfel, G. A.

In-stent restenosis (ISR) is one of the main drawbacks of stent implementation which limits the long-term success of the procedure. Morphological changes occurring within the arterial wall due to stent-induced mechanical injury are a major cause for activation of vascular smooth muscle cells (VSMCs), and the subsequent development of ISR. Considering the theory of volumetric mass growth and adopting a multiplicative decomposition of the deformation gradient into an elastic part and a growth part, we present a mechanobiological model for ISR. An evolution equation is developed for mass growth of the neointima, in which the activation of VSMCs due to stent-induced damage (injury) and the proliferation rate of the activated cells are considered. By introducing the mass evolution into the mass balance equation, we obtain the evolution of the growth tensor over time. The model is implemented in a finite element code and the procedure of angioplasty is simulated, whereby the features of the proposed growth model are illustrated.

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.

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

Directory of Open Access Journals (Sweden)

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.

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

Directory of Open Access Journals (Sweden)

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 treatment of acutely ruptured, wide-necked anterior communicating artery aneurysms using the Enterprise stent.

Science.gov (United States)

Huang, Qing-Hai; Wu, Yong-Fa; Shen, Jie; Hong, Bo; Yang, Peng-Fei; Xu, Yi; Zhao, Wen-Yuan; Liu, Jian-Min

2013-02-01

The treatment of anterior communicating artery (AcomA) wide-necked aneurysms with the Enterprise stent (Codman, Miami Lakes, FL, USA) has not been commonly described, due to the complexity of the vascular anatomy and the small vessels of the AcomA complex. To evaluate the feasibility, effectiveness and safety of Enterprise stent placement in AcomA aneurysms, we performed this retrospective study. Between November 2008 and December 2010, 27 wide-necked AcomA ruptured aneurysms were treated within 72 hours of ictus with the Enterprise stent. Data collected and analyzed were: demographic data, morphologic features of the aneurysm, treatment results and follow-up results. Twenty-nine Enterprise stents were successfully deployed in all 27 aneurysms, including Y-configuration stent deployment in two patients. The initial embolization degrees were Raymond class I in 20 patients, class II in five and class III in the other two. The angiographic follow-up of 21 patients (mean, 8.4 months) showed that all aneurysms remained stable or improved; there was no in-stent stenosis, recurrence or retreatment. The clinical follow-up of 26 patients (mean, 12.6 months) showed that 23 patients displayed no symptoms and no or mild disability; three patients remained with severe or moderately severe disability. The Enterprise stent is feasible and safe for endovascular embolization of wide-necked AcomA ruptured aneurysms. Further follow up is needed to assess the long-term efficacy of Enterprise stent placement in AcomA. Copyright © 2012 Elsevier Ltd. All rights reserved.

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.

Construction of a fucoidan/laminin functional multilayer to direction vascular cell fate and promotion hemocompatibility

International Nuclear Information System (INIS)

Ye, Changrong; Wang, Yan; Su, Hong; Yang, Ping; Huang, Nan; Maitz, Manfred F.; Zhao, Anshan

2016-01-01

Surface biofunctional modification of cardiovascular stents is a versatile approach to reduce the adverse effects after implantation. In this work, a novel multifunctional coating was fabricated by coimmobilization of the sulfated polysaccharide of brown algae fucoidan and laminin to biomimic the vascular intimal conditions in order to support rapid endothelialization, prevent restenosis and improve hemocompatibility. The surface properties of the coating such as hydrophilicity, bonding density of biomolecules and stability were evaluated and optimized. According to the biocompatibility tests, the fucoidan/laminin multilayer coated surface displayed less platelet adhesion with favorable anticoagulant property. In addition, the fucoidan/laminin complex showed function to selectively regulate vascular cells growth behavior. The proliferation of endothelial cells (ECs) on the fucoidan/laminin biofunctional coating was significantly promoted. For the smooth muscle cells (SMCs), inhibitory effects on cell adhesion and proliferation were observed. In conclusion, the fucoidan/laminin biofunctional coating was successfully fabricated with desirable anticoagulant and endothelialization properties which show a promising application in the vascular devices such as vascular stents or grafts surface modification. - Highlights: • Construction of fucoidan/laminin functional multilayer to biomimic the basement membrane of vascular • The fucoidan/laminin complex demonstrates anti-coagulation property. • The fucoidan/laminin complex can selectively regulate EC and SMC growth behavior to prevent restenosis.

Construction of a fucoidan/laminin functional multilayer to direction vascular cell fate and promotion hemocompatibility

Energy Technology Data Exchange (ETDEWEB)

Ye, Changrong; Wang, Yan; Su, Hong; Yang, Ping; Huang, Nan [Key Laboratory of Advanced Materials Technology of Ministry of Education, Department of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031 (China); Maitz, Manfred F. [Leibniz Institute of Polymer Research Dresden, Max Bergmann Center of Biomaterials Dresden, Dresden 01069 (Germany); Zhao, Anshan [Key Laboratory of Advanced Materials Technology of Ministry of Education, Department of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031 (China)

2016-07-01

Surface biofunctional modification of cardiovascular stents is a versatile approach to reduce the adverse effects after implantation. In this work, a novel multifunctional coating was fabricated by coimmobilization of the sulfated polysaccharide of brown algae fucoidan and laminin to biomimic the vascular intimal conditions in order to support rapid endothelialization, prevent restenosis and improve hemocompatibility. The surface properties of the coating such as hydrophilicity, bonding density of biomolecules and stability were evaluated and optimized. According to the biocompatibility tests, the fucoidan/laminin multilayer coated surface displayed less platelet adhesion with favorable anticoagulant property. In addition, the fucoidan/laminin complex showed function to selectively regulate vascular cells growth behavior. The proliferation of endothelial cells (ECs) on the fucoidan/laminin biofunctional coating was significantly promoted. For the smooth muscle cells (SMCs), inhibitory effects on cell adhesion and proliferation were observed. In conclusion, the fucoidan/laminin biofunctional coating was successfully fabricated with desirable anticoagulant and endothelialization properties which show a promising application in the vascular devices such as vascular stents or grafts surface modification. - Highlights: • Construction of fucoidan/laminin functional multilayer to biomimic the basement membrane of vascular • The fucoidan/laminin complex demonstrates anti-coagulation property. • The fucoidan/laminin complex can selectively regulate EC and SMC growth behavior to prevent restenosis.

Self-Expandable Stent Placement in Infrapopliteal Arteries After Unsuccessful Angioplasty Failure: One-Year Follow-up

International Nuclear Information System (INIS)

Peregrin, J. H.; Smirova, S.; Koznar, B.; Novotny, J.; Kovac, J.; Lastovickova, J.; Skibova, J.

2008-01-01

The purpose of this prospective study was to evaluate whether stent placement in infrapopliteal arteries is helpful in failed percutaneous transluminal angioplasty (PTA). Infrapopliteal PTA was performed in 70 arteries of 66 patients with chronic critical lower limb ischemia. The group comprised 55 males and 11 females, with an average age of 63.4 (range, 42-82) years. Diabetes mellitus was present in 92.4% of patients. Only the palpable anterior tibial and posterior tibial arteries were evaluated. Stents (Xpert stent; Abbot Vascular, Redwood City, CA, USA) were placed in 16 arteries where PTA was not successful (the failure was defined as residual stenosis >30% after PTA). In 54 arteries simple PTA was performed and was technically successful. Twenty-four nondilated arteries with no significant stenosis served as a comparison group. The 12-month patency rate was evaluated according to a combination of palpation and Doppler ultrasound. In all cases stent placement restored the flow in the artery immediately after unsuccessful PTA. Twelve-month follow-up showed a patency rate of 82% in the PTA group, 78% in the stent group, and 69% in the comparison group. We conclude that stent placement in the case of unsuccessful infrapopliteal PTA changed technical failure to success and restored flow in the dilated artery. At 12-month follow-up the patency rate of infrapopliteal arteries stented for PTA failure did not differ significantly either from nonstented arteries with an optimal PTA result or from a comparison group of nonintervened arteries.

Preliminary Report of Carotid Artery Stenting Using a Tapered Stent

Energy Technology Data Exchange (ETDEWEB)

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.

Gravity-induced asymmetric distribution of a plant growth hormone

Science.gov (United States)

Bandurski, R. S.; Schulze, A.; Momonoki, Y.

1984-01-01

Dolk (1936) demonstrated that gravistimulation induced an asymmetric distribution of auxin in a horizontally-placed shoot. An attempt is made to determine where and how that asymmetry arises, and to demonstrate that the endogenous auxin, indole-3-acetic acid, becomes asymmetrically distributed in the cortical cells of the Zea mays mesocotyl during 3 min of geostimulation. Further, indole-3-acetic acid derived by hydrolysis of an applied transport form of the hormone, indole-3-acetyl-myo-inositol, becomes asymmetrically distributed within 15 min of geostimulus time. From these and prior data is developed a working theory that the gravitational stimulus induces a selective leakage, or secretion, of the hormone from the vascular tissue to the cortical cells of the mesocotyl.

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

Toxic vessel reaction to an absorbable polymer-based paclitaxel-eluting stent in pig coronary arteries.

Science.gov (United States)

Jabara, Refat; Chronos, Nicolas; Tondato, Fernando; Conway, Damian; Molema, Warner; Park, Kenneth; Mabin, Tom; King, Spencer; Robinson, Keith

2006-08-01

The goal of this study was to evaluate a new drug-eluting stent (DES) comprising a bioabsorbable polymer eluting a moderate dose of paclitaxel in a clinically relevant animal model. Although DES limit restenosis, adverse vascular pathologies and toxicities continue to be of major concern. Optimization of DES components, especially completely absorbable polymers, may reduce these toxicities. Bare-metal (BM), absorbable polymer coating only (POLY), and polymer-based paclitaxel-eluting (PACL) stents were implanted in porcine coronary arteries using intravascular ultrasound (IVUS) to optimize stent apposition. The dose density of paclitaxel was 0.30-0.35 mcg/mm2, with in vitro elution studies demonstrating a gradual elution over 6-8 weeks. The animals were terminated at 1 week, 1 month and 3 months. Histopathologic and histomorphometric analyses were perform. The arteries with PACL showed extensive smooth muscle cell necrosis at 1 week and poor apposition of stent struts at 1 month (malapposition measured as gap width between strut and internal elastic lamina), with greater gap width compared to the BM and POLY groups (0.22 mm +/- 0.02 vs. 0.03 mm +/- 0.02 and 0.02 mm +/- 0.01, respectively; p stent malapposition and late neointimal thickening. Since the therapeutic window for paclitaxel may be narrower than currently inferred, thorough preclinical testing coupled with the polymer development process for stents eluting paclitaxel is needed.

Successful endovascular treatment of a hemodialysis graft pseudoaneurysm by covered stent and direct percutaneous thrombin injection.

LENUS (Irish Health Repository)

Keeling, Aoife N

2011-07-25

Vascular access for hemodialysis remains a challenge for nephrologists, vascular surgeons, and interventional radiologists alike. Arteriovenous fistula and synthetic grafts remain the access of choice for long-term hemodialysis; however, they are subject to complications from infection and repeated needle cannulation. Pseudoaneurysms are an increasingly recognized adverse event. At present, there are many minimally invasive methods to repair these wall defects. We present a graft pseudoaneurysm, which required a combination of endovascular stent graft placement and percutaneous thrombin injection for successful occlusion.

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.

A Phase II study of external-beam radiotherapy and endovascular brachytherapy with PTA and stenting for femoropopliteal artery restenosis

International Nuclear Information System (INIS)

Narayan, Kailash; Denton, Michael; Das, Ram; Bernshaw, David; Rolfo, Aldo; Dyk, Sylvia van; Mirakian, Alex

2006-01-01

Purpose: To assess the safety and seek evidence of efficacy of combined external-beam radiotherapy (EBRT) and endovascular brachytherapy in the treatment of stenotic vascular lesions. Methods and Materials: Seventeen patients with high risk for restenosis of femoropopliteal arteries were enrolled in this study from February 2000 to August 2002. The external beam radiotherapy regimen consisted of 10 Gy in 5 fractions of 2 Gy, starting on Day 0. This was followed on Day 6 by angiography, stent placement, and intraluminal brachytherapy to a dose of 10 Gy at 1.2 mm from stent surface. The EBRT was continued from the same day to another 10 Gy in 2 Gy daily fractions for 5 days. Results: The follow up ranged from 33 months to 60 months. At the time of analysis 15 of 17 patients were alive with patent stents. Of these, 10 were symptom-free. Two patients died of unrelated causes. Conclusions: The combination of EBRT and endovascular brachytherapy provided adequate dose distribution without any geographical miss or 'candy wrapper' restenosis. No incidence of aneurysmal dilation of radiated vascular segment was observed. The treatment was feasible, well tolerated, and achieved 88% stenosis free survival

Enhanced performance of magnesium alloy for drug-eluting vascular scaffold application

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Dong, Hongzhou; Li, Daikun; Mao, Daoyong; Bai, Ningning; Chen, Yashi; Li, Qing

2018-03-01

Bio-absorbable magnesium alloys drug-eluting vascular scaffold was developed to resolve the defect of permanent metal and drug-eluting stents, most notably a chronic vessel wall inflammation and the risk of stent thrombosis. Nevertheless, violent chemical reaction and rapid degradation under physiological conditions limits their application. Furthermore, multifunctional drug-eluting stents which could reduce the formation of thrombus and repair the damaged vessels need more attention to fundamentally cure the coronary artery disease. Herein, a drug delivery system (Mg/MgO/PLA-FA) which can realize sustainable release of ferulaic acid was designed via anodic oxidation process and dip coating process. Electrochemical tests and immersion experiments showed that the superior anticorrosion behavior, it is due to the dense MgO-PLA composite layer. The released ferulaic acid can effectively decrease platelets adhesion and aggregation during the early stage of implantation. Besides, hemolysis tests showed that the composite coatings endowed the Mg alloy with a low hemolysis ratio. The Mg/MgO/PLA-FA composite materials may be appropriate for applications on biodegradable Mg alloys drug-eluting stents.

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.

Flow patterns from metallic vascular endoprostheses: in vitro results

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Mueller-Huelsbeck, S.; Grimm, J.; Jahnke, T.; Haeselbarth, G.; Heller, M. [Dept. of Radiology, University Hospital, Kiel (Germany)

2001-05-01

The aim of this study was to determine flow characteristics and pressure gradients of different balloon- and self-expandable stents in an in vitro flow-model. Seven vascular stents (Bridge, Cragg, Memotherm, Palmaz PS 784, Sinus, Symphony, Wallstent), equal in length (60 mm) and diameter (10 mm), were deployed in a closed flow model. The inner diameter of the tube measured 9 mm. Flow at 1.5 and 6 l/min was applied. Flow patterns were visualized by anionic particles illuminated with two helium-neon lasers. Late laminary flow characteristics and pre- /post-stent pressure gradients were determined in either expanded stent, 25 and 50 % tube stenosis. Stent implantation induced a decrease of laminary flow when compared with an unstented tube with and without concentric 25 % stenosis (p < 0.01) at all flow rates and an increase of pressure gradients when compared with an unstented tube for a flow rate of 6 l/min and all stenoses (p < 0.01). At 1.5 l/min most stents revealed no significant change of pressure gradient, the highest gradient measured 4.0 mmHg. Sinus permitted maximum (expanded: 82.1 % and 76.9 % at 25 % stenosis at 1.5 l/min; p < 0.01) and Palmaz minimum of laminary flow at all flow rates and stenoses (70.2 and 52.4 % at 25 % stenosis at 1.5 l/min; p < 0.01). At 6 l/min, when completely expanded, Sinus is equal to Bridge and Memotherm; in 25 % stenosis Sinus is equal to Bridge, Memotherm, and additionally to Cragg and Wall. None of the endoprostheses revealed laminary flow at 50 % stenosis. Inadequate stent deployment bears the risk of creating less laminary flow and pressure gradients. Since flow disturbances and pressure gradients may influence neointimal hyperplasia, stent design and completeness of stent expansion are important factors regarding the appearance of thrombus formation and postinterventional restenosis. (orig.)

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.

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)

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.

Complications in percutaneous transluminal stenting for carotid artery stenosis

International Nuclear Information System (INIS)

Li Shenmao; Miao Zhongrong; Zhu Fengshui; Ji Xunming; Jiao Liqun; Qi Jianshu; Ling Feng

2007-01-01

Objective: To discuss the complications of endovascular stenting for carotid artery stenosis. Methods: Cerebral vascular angiography and cervical Doppler sonography were performed in 648 patients with carotid artery stenosis. Emboli-protected device was used in 365 patients and none in 283 patients. Results: All 648 patients were technically successful (100%). Symptoms disappeared or improved in 78.7% patients. Slow heart rate during operation existed in 26.4% patients. Embolism caused by dislodgment of emboli occurred in 5 patients, 3 of them recovered after treatment and 2 had unilateral dyskinesias. Intracranial hemorrhage occurred in 3 patients. Stroke or death within 30 days after operation occurred in 6 patients(1.24%). 322 patients (77.8%)were followed up. Restenosis occurred in 17 patients(3.3%). Conclusion: Percutaneous transluminal stenting is a safe option for carotid artery stenosis. Correct evaluation of clinical and angiographic data before operation, together with normative manipulation and nursing during and after operation are the key points to avoid complications. (authors)

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

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.

Adhesion and endothelialization of endothelial cells on the surface of endovascular stents by the novel rotational culture of cells

International Nuclear Information System (INIS)

Tang Chaojun; Wang Guixue; Cao Yi; Wu Xue; Xie Xiang; Xiao Li

2008-01-01

Recent researches indicate that the initial event in the implantation of endovascular stents involves mechanical injury to the vessel wall. Confluent endothelialization of vascular grafts in vitro before implantation has been suggested as a way to reduce injury of the blood vessel. The purpose of this study is to establish a useful way to improve the adhesion of endothelial cells and accelerate endothelialization on the surface of endovascular stents by a novel rotational culture device. Numerical simulation was used to predict the shear stress on the surface of stents. The number of cellular adhesion was calculated by cell counting, the cell growth was observed by scanning electron microscope and fluorescence microscope. Numerical simulation results showed that the stents was exposed to shear stress of 2.66 x 10 -3 to 8.88 x 10 -2 Pa. Rotational culture of human umbilical vein endothelial cells could enhance the adhesion of cells and accelerate endothelialization on the surface of stents when the culture conditions for EC adhesion were intermediate rotation speed, higher dynamic incubation times, lower cell densities

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

Energy Technology Data Exchange (ETDEWEB)

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.

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.

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.

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

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

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

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Hohenforst-Schmidt W

2017-05-01

Full Text Available Wolfgang Hohenforst-Schmidt,1 Paul Zarogoulidis,2 Michael Steinheimer,1 Thomas Schneider,1 Naim Benhassen,1 Holger Rupprecht,3 Lutz Freitag4 1Medical Clinic I, “Fuerth” Hospital, University of Erlangen, Fuerth, Germany; 2Pulmonary Department-Oncology Unit, “G Papanikolaou” General Hospital, Aristotle University of Thessaloniki, Thessaloniki, Greece; 3Department of General, Vascular and Thoracical Surgery, “Fuerth” Hospital, University of Erlangen, Fuerth, 4Department of Interventional Pneumology, Ruhrlandklinik, University Hospital Essen, University of Essen-Duisburg, Essen, Germany Introduction: Stents have been used for quite some time for the treatment of benign and malignant airway stenosis. Silicon stents are preferred for benign situations, whereas metallic self-expanding stents are preferred for malignant comorbidities.Patient and methods: In general, stents can be placed in different approach directions, although in pulmonary medicine it is logical to apply only antegrade techniques – until now. A 63-year-old patient, 168 cm height and 53 kg weight on referral, suffered chronical diseases. The patient was diagnosed with a papillary thyroid carcinoma in 1989, which was treated by resection and radiotherapy. In the following years, she developed a stenosis of the esophagus. The decision to try endobronchial stenting was made upon the plan to close that fistula with a pedicled omentum majus replacement through the diaphragmal opening of the esophagus. This surgical plastic needed an abutment and a secured continuous airway replacement above the tracheostoma level. A Freitag stent (FS, 11 cm in length (110–25–40 and an inner diameter of 13 mm, was placed successfully retrograde into the trachea and completely bridged the big fistula. Unfortunately the patient passed away due to pulmonary infections after several weeks.Discussion: In this case report, a successful but unusual case of retrograde stent placement of a modified

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

Science.gov (United States)

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.

In vitro performance investigation of bioresorbable scaffolds - Standard tests for vascular stents and beyond.

Science.gov (United States)

Schmidt, Wolfram; Behrens, Peter; Brandt-Wunderlich, Christoph; Siewert, Stefan; Grabow, Niels; Schmitz, Klaus-Peter

2016-09-01

Biodegradable polymers are the main materials for coronary scaffolds. Magnesium has been investigated as a potential alternative and was successfully tested in human clinical trials. However, it is still challenging to achieve mechanical parameters comparative to permanent bare metal (BMS) and drug-eluting stents (DES). As such, in vitro tests are required to assess mechanical parameters correlated to the safety and efficacy of the device. In vitro bench tests evaluate scaffold profiles, length, deliverability, expansion behavior including acute elastic and time-dependent recoil, bending stiffness and radial strength. The Absorb GT1 (Abbott Vascular, Temecula, CA), DESolve (Elixir Medical Corporation, Sunnyvale, CA) and the Magmaris (BIOTRONIK AG, Bülach, Switzerland) that was previously tested in the BIOSOLVE II study, were tested. Crimped profiles were 1.38±0.01mm (Absorb GT1), 1.39±0.01mm (DESolve) and 1.44±0.00mm (Magmaris) enabling 6F compatibility. Trackability was measured depending on stiffness and force transmission (pushability). Acute elastic recoil was measured at free expansion and within a mock vessel, respectively, yielding results of 5.86±0.76 and 5.22±0.38% (Absorb), 7.85±3.45 and 9.42±0.21% (DESolve) and 5.57±0.72 and 4.94±0.31% (Magmaris). Time-dependent recoil (after 1h) was observed for the Absorb and DESolve scaffolds but not for the Magmaris. The self-correcting wall apposition behavior of the DESolve did not prevent time-dependent recoil under vessel loading. The results of the suggested test methods allow assessment of technical feasibility based on objective mechanical data and highlight the main differences between polymeric and metallic bioresorbable scaffolds. Copyright © 2016 Elsevier Inc. All rights reserved.

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.

Unstable patients with retroperitoneal vascular trauma: an endovascular approach.

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Boufi, Mourad; Bordon, Sébastien; Dona, Bianca; Hartung, Olivier; Sarran, Anthony; Nadeau, Sébastien; Maurin, Charlotte; Alimi, Yves S

2011-04-01

In hemodynamically unstable patients, the management of retroperitoneal vascular trauma is both difficult and challenging. Endovascular techniques have become an alternative to surgery in several trauma centers. Between 2004 and 2006, 16 patients (nine men, mean age: 46 years, range: 19-79 years) with retroperitoneal vascular trauma and hemodynamic instability were treated using an endovascular approach. The mean injury severity score was 30.7 ± 13.1. Mean systolic blood pressure and the shock index were 74 mm Hg and 1.9, respectively. Vasopressor drugs were required in 68.7% of cases (n = 11). Injuries were attributable to road traffic accidents (n = 15) and falls (n = 1). The hemorrhage sites included the internal iliac artery or its branches (n = 12) with bilateral injury in one case, renal artery (n = 2), abdominal aorta (n = 1), and lumbar artery (n = 1). In all, 14 coil embolizations and three stent-grafts were implanted. The technical success rate was 75%, as early re-embolization was necessary in one case and three patients died during the perioperative period. Six patients died during the period of hospitalization (37.5%). No surgical conversion or major morbidity was reported. In comparison with particulates, coil ± stent-graft may provide similar efficacy with regard to survival, and thus may be a valuable solution when particulate embolization is not available or feasible. Copyright © 2011 Annals of Vascular Surgery Inc. Published by Elsevier Inc. All rights reserved.

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

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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.

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

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

2016-04-01

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

Thalamic hemorrhage following carotid angioplasty and stenting

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Friedman, Jonathan A.; Kallmes, David F.; Wijdicks, Eelco F.M.

2004-01-01

Carotid angioplasty and stenting (CAS) has emerged as an alternative treatment of carotid stenosis for patients poorly suited for endarterectomy. Intracerebral hemorrhage following carotid revascularization is rare and thought to be related to hyperperfusion injury in most cases. Early experience suggests an increased incidence of hemorrhage following CAS as compared to endarterectomy. We describe a patient who suffered a thalamic hemorrhage following CAS. Because this hemorrhage occurred in a vascular territory unlikely to have been supplied by the treated artery, this case suggests that the mechanism of intracerebral hemorrhage following CAS may in some cases be different from the hyperperfusion hemorrhage classically described following endarterectomy. (orig.)

New stent design for use in small coronary arteries during percutaneous coronary intervention

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Juan F Granada

2010-10-01

Full Text Available Juan F Granada1, Barbara A Huibregtse2, Keith D Dawkins21The Jack H Skirball Center for Cardiovascular Research, Cardiovascular Research Foundation, Columbia University Medical Center, New York, NY, USA; 2Boston Scientific Corporation, Natick, MA, USAAbstract: Patients with diabetes mellitus, of female gender, increased age, and/or with peripheral vascular disease often develop coronary stenoses in small caliber vessels. This review describes treatment of these lesions with the paclitaxel-eluting 2.25 mm TAXUS® Liberté® Atom™ stent. Given the same stent composition, polymer, antirestenotic drug (paclitaxel, and release kinetics as the first-generation 2.25 mm TAXUS® Express® Atom™ stent, the second-generation TAXUS Liberté Atom stent incorporates improved stent design characteristics, including thinner struts (0.0038 versus 0.0052 inches, intended to increase conformability and deliverability. In a porcine noninjured coronary artery model, TAXUS Liberté Atom stent implantation in small vessels demonstrated complete strut tissue coverage compared with the bare metal stent control, suggesting a similar degree of tissue healing between the groups at 30, 90, and 180 days. The prospective, single-armed TAXUS ATLAS Small Vessel trial demonstrated improved instent late loss (0.28 ± 0.45 versus 0.84 ± 0.57 mm, P < 0.001, instent binary restenosis (13.0% versus 38.1%, P < 0.001, and target lesion revascularization (5.8% versus 17.6%, P < 0.001 at nine months with the TAXUS Liberté Atom stent as compared with the bare metal Express stent control, with similar safety measures between the two groups. The TAXUS Liberté Atom also significantly reduced nine-month angiographic rates of both instent late loss (0.28 ± 0.45 versus 0.44 ± 0.61 mm, P = 0.03 and instent binary restenosis (13.0% versus 25.9%, P = 0.02 when compared with the 2.25 mm TAXUS Express Atom control. The observed reduction in target lesion revascularization with the TAXUS

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

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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.

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

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

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

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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.

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

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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).

Stent-assisted coil embolization of aneurysms with small parent vessels: safety and efficacy analysis.

Science.gov (United States)

Kühn, Anna Luisa; Hou, Samuel Y; Puri, Ajit S; Silva, Christine F; Gounis, Matthew J; Wakhloo, Ajay K

2016-06-01

Stent-assisted coil embolization (SACE) is a viable therapeutic approach for wide-neck intracranial aneurysms. However, it can be technically challenging in small cerebral vessels (≤2 mm). To present our experience with stents approved for SACE in aneurysms with small parent arteries. All patients who underwent stent-assisted aneurysm treatment with either a Neuroform or an Enterprise stent device at our institution between June 2006 and October 2012 were identified. Additionally, we evaluated each patient's vascular risk factors, aneurysm characteristics (ruptured vs non-ruptured, incidental finding, recanalized) and follow-up angiography data. A total of 41 patients with 44 aneurysms met our criteria, including 31 women and 10 men. Most of the aneurysms were located in the anterior circulation (75%). Stent placement in vessels 1.2-2 mm in diameter was successful in 93.2%. Thromboembolic complications occurred in 6 cases and vessel straightening was seen in 1 case only. Initial nearly complete to complete aneurysm obliteration was achieved in 88.6%. Six-month follow-up angiography showed coil compaction in three cases, one asymptomatic in-stent stenosis and stent occlusion. Twelve to 20-months' follow-up showed stable coil compaction in two patients compared with previous follow-up, and aneurysm recanalization in two patients. Twenty-four to 36-months' follow-up showed further coil compaction in one of these patients and aneurysm recanalization in a previous case of stable coil compaction on mid-term follow-up. Our results suggest that SACE of aneurysms with small parent vessels is feasible in selected cases and shows good long-term patency rates of parent arteries. 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/

Closed-Cell Stent-Assisted Coiling of Intracranial Aneurysms: Evaluation of Changes in Vascular Geometry Using Digital Subtraction Angiography.

Science.gov (United States)

Beller, Ebba; Klopp, David; Göttler, Jens; Kaesmacher, Johannes; Zimmer, Claus; Kirschke, Jan S; Prothmann, Sascha

2016-01-01

Stent-assisted coil embolization (SACE) plays an important role in the treatment of intracranial aneurysms. The purpose of this study was to investigate geometrical changes caused by closed-cell design stents in bifurcation and sidewall aneurysms. 31 patients with 34 aneurysms underwent SACE with closed-cell design stents. Inflow angle α, determined by aneurysm neck and afferent vessel, and angle between afferent and efferent vessel close to (δ1), respectively, more remote from the aneurysm neck (δ2) were graphically determined in 2D angiography projections. Stent assisted coiling resulted in a significant increase of all three angles from a mean value (±SEM) of α = 119° (±6.5°) pretreatment to 130° (±6.6°) posttreatment (P ≤ .001), δ1 = 129° (±6.4°) to 139° (±6.1°), (P ≤ .001) and δ2 = 115° (±8.4°) to 126° (±7.5°), (P ≤ .01). Angular change of δ1 in AcomA aneurysms was significant greater compared to sidewall aneurysms (26°±4.9° versus 8°± 2.3°, P ≤ .05). The initial angle of δ1 and δ2 revealed a significantly inverse relationship to the angle increase (δ1: r = -0.41, P ≤ .05 and δ2: r = -0.47, P ≤ .01). Moreover, angle δ1 was significantly higher in unruptured compared to ruptured aneurysms (135°±7.1° versus 103°±10.8°, P ≤ .05). Stent deployment modulates the geometry of the aneurysm-vessel complex, which may lead to favorable hemodynamic changes more similar to unruptured than to ruptured aneurysms. Our findings also suggest that the more acute-angled aneurysm-vessel anatomy, the larger the angular change. Further studies are needed to investigate whether these changes improve the clinical outcome.

Closed-Cell Stent-Assisted Coiling of Intracranial Aneurysms: Evaluation of Changes in Vascular Geometry Using Digital Subtraction Angiography.

Directory of Open Access Journals (Sweden)

Ebba Beller

Full Text Available Stent-assisted coil embolization (SACE plays an important role in the treatment of intracranial aneurysms. The purpose of this study was to investigate geometrical changes caused by closed-cell design stents in bifurcation and sidewall aneurysms.31 patients with 34 aneurysms underwent SACE with closed-cell design stents. Inflow angle α, determined by aneurysm neck and afferent vessel, and angle between afferent and efferent vessel close to (δ1, respectively, more remote from the aneurysm neck (δ2 were graphically determined in 2D angiography projections.Stent assisted coiling resulted in a significant increase of all three angles from a mean value (±SEM of α = 119° (±6.5° pretreatment to 130° (±6.6° posttreatment (P ≤ .001, δ1 = 129° (±6.4° to 139° (±6.1°, (P ≤ .001 and δ2 = 115° (±8.4° to 126° (±7.5°, (P ≤ .01. Angular change of δ1 in AcomA aneurysms was significant greater compared to sidewall aneurysms (26°±4.9° versus 8°± 2.3°, P ≤ .05. The initial angle of δ1 and δ2 revealed a significantly inverse relationship to the angle increase (δ1: r = -0.41, P ≤ .05 and δ2: r = -0.47, P ≤ .01. Moreover, angle δ1 was significantly higher in unruptured compared to ruptured aneurysms (135°±7.1° versus 103°±10.8°, P ≤ .05.Stent deployment modulates the geometry of the aneurysm-vessel complex, which may lead to favorable hemodynamic changes more similar to unruptured than to ruptured aneurysms. Our findings also suggest that the more acute-angled aneurysm-vessel anatomy, the larger the angular change. Further studies are needed to investigate whether these changes improve the clinical outcome.

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

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.

Percutaneous biliary drainage and stenting

International Nuclear Information System (INIS)

Totev, M.

2012-01-01

Full text: Percutaneous transhepatic cholangiography (PTC) is an X-ray or US guided procedure that involves the injection of a contrast material directly into the bile ducts inside the liver to produce pictures of them. If a blockage or narrowing is found, additional procedures may be performed: 1. insertion of a catheter to drain excess bile out of the body or both - internal and external; 2. plastic endoprothesis placement; 3. self-expandable metal stents placement to help open bile ducts or to bypass an obstruction and allow fluids to drain. Current percutaneous biliary interventions include percutaneous transhepatic cholangiography (PTC) and biliary drainage to manage benign and malignant obstructions. Internal biliary stents are either plastic or metallic, and various types of each kind are available. Internal biliary stents have several advantages. An external tube can be uncomfortable and have a psychological disadvantage. An internal stent prevents the problems related to external catheters, for example, pericatheter leakage of bile and the need for daily flushing. The disadvantages include having to perform endoscopic retrograde cholangiopancreatography (ERCP) or new PTC procedures to obtain access in case of stent obstruction. Better patency rates are reported with metallic than with plastic stents in cases of malignant obstruction, though no effect on survival is noted. Plastic internal stents are the cheapest but reportedly prone to migration. Metallic stents are generally not used in the treatment of benign disease because studies have shown poor long-term patency rates. Limited applications may include the treatment of patients who are poor surgical candidates or of those in whom surgical treatment fails. Most postoperative strictures are treated surgically, though endoscopic and (less commonly) percutaneous placement of nonmetallic stents has increasingly been used in the past few years. Now there are some reports about use of biodegradable biliary

[Absorbable coronary stents. New promising technology].

Science.gov (United States)

Erbel, Raimund; Böse, Dirk; Haude, Michael; Kordish, Igor; Churzidze, Sofia; Malyar, Nasser; Konorza, Thomas; Sack, Stefan

2007-06-01

Coronary stent implantation started in Germany 20 years ago. In the beginning, the progress was very slow and accelerated 10 years later. Meanwhile, coronary stent implantation is a standard procedure in interventional cardiology. From the beginning of permanent stent implantation, research started to provide temporary stenting of coronary arteries, first with catheter-based systems, later with stent-alone technology. Stents were produced from polymers or metal. The first polymer stent implantation failed except the Igaki-Tamai stent in Japan. Newly developed absorbable polymer stents seem to be very promising, as intravascular ultrasound (IVUS) and optical coherence tomography have demonstrated. Temporary metal stents were developed based on iron and magnesium. Currently, the iron stent is tested in peripheral arteries. The absorbable magnesium stent (Biotronik, Berlin, Germany) was tested in peripheral arteries below the knee and meanwhile in the multicenter international PROGRESS-AMS (Clinical Performance and Angiographic Results of Coronary Stenting with Absorbable Metal Stents) study. The first magnesium stent implantation was performed on July 30, 2004 after extended experimental testing in Essen. The magnesium stent behaved like a bare-metal stent with low recoil of 5-7%. The stent struts were absorbed when tested with IVUS. Stent struts were not visible by fluoroscopy or computed tomography (CT) as well as magnetic resonance imaging (MRI). That means, that the magnesium stent is invisible and therefore CT and MRI can be used for imaging of interventions. Only using micro-CT the stent struts were visible. The absorption process could be demonstrated in a patient 18 days after implantation due to suspected acute coronary syndrome, which was excluded. IVUS showed a nice open lumen. Stent struts were no longer visible, but replaced by tissue indicating the previous stent location. Coronary angiography after 4 months showed an ischemia-driven target lesion

Flow-diverting Stent in the Treatment of Cervical Carotid Dissection and Pseudoaneurysm: Review of Literature and Case Report.

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Baptista-Sincos, Anna Paula Weinhardt; Simplício, Aline Bigatão; Sincos, Igor Rafael; Leaderman, Alex; Neto, Fernando Saliture; Moraes, Adjaldes; Aun, Ricardo

2018-01-01

The endovascular technique has been recommended over the past few years to extracranial carotid dissection and pseudoaneurysm with promising results, especially after medical therapy failure. Flow-diverting stents are an alternative for complex cases. These stents have proven to be effective treatment devices for intracranial aneurysms. The reference list of Pham's systematic review, published in 2011, and Seward's literature review, published in 2015, was considered, as well as all new articles with eligible features. Search was conducted on specific databases: MEDLINE and Literatura Latino-Americana e do Caribe em Ciências da Saúde. For carotid dissection and pseudoaneurysm, our review yielded 3 published articles including 12 patients. The technical success rate of flow-diverting stent was 100% with no procedural complication described. Mean clinical follow-up was 27.2 months (range 5-48), and in 5 months' angiographic follow-up, all lesions had healed. No new neurological events were reported during the clinical follow-up. Flow diverter stent use on intracranial and peripheral vascular surgery demonstrates satisfactory initial results, but it is still under investigation. There are very few cases treated till now and the initial results with flow-diverting stents to cervical carotid dissection are promising. In well-selected cases, where simple embolization or conventional stent is not appropriate, this technic may be considered. Copyright © 2017 Elsevier Inc. All rights reserved.

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

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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....

Comparison of midterm results for the Talent and Endurant stent graft.

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't Mannetje, Yannick W; Cuypers, Philippe W M; Saleem, Ben R; Bode, Aron S; Teijink, Joep A W; van Sambeek, Marc R H M

2017-09-01

Stent graft evolution is often addressed as a cause for improved outcomes of endovascular aneurysm repair for patients with an abdominal aortic aneurysm. In this study, we directly compared the midterm result of Endurant stent graft with its predecessor, the Talent stent graft (both Medtronic, Santa Rosa, Calif). Patient treated from January 2005 to December 2010 in a single tertiary center in The Netherlands with a Talent or Endurant stent graft were eligible for inclusion. Ruptured abdominal aortic aneurysms or patients with previous aortic surgery were excluded. The primary end point was the Kaplan-Meier estimated freedom from secondary interventions. Secondary end points were perioperative outcomes and indications for secondary interventions. In total, 221 patients were included (131 Endurant and 90 Talent). At baseline, the median aortic bifurcation was narrower for the Endurant (30 mm vs 39 mm; P Talent and Endurant, respectively. The estimated freedom from secondary interventions at 30 days, 1 year, 5 years, and 7 years was 94.3%, 89.4%, 72.2%, and 64.1% for Talent and 96.8%, 89.3%, 75.2%, and 69.2% for Endurant (P = .528). The indication for secondary interventions does differ; more patients required an intervention for a proximal neck-related complication (type Ia endoleak or migration) in the Talent group (18.2% vs 4.8%; P = .001), whereas more interventions for iliac limb stenosis were seen in the Endurant group (0.0% vs 4.8%; P = .044). In a binomial regression analysis, suprarenal angulation, infrarenal neck length, and type of stent graft were independent predictors of neck-related complications. Evolution from the Talent stent graft into the Endurant has resulted in significant reduction of infrarenal neck-related complications; on the other hand, iliac interventions increased. The overall midterm secondary intervention rate was comparable. Copyright © 2017 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

Percutaneous placement of ureteral stent

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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.

[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.

Experimental absorbable stent permits airway remodeling.

Science.gov (United States)

Liu, Kuo-Sheng; Liu, Yun-Hen; Peng, Yi-Jie; Liu, Shih-Jung

2011-02-01

Despite metallic and silicone stents being effective in treating various airway lesions, many concerns still remain. A bioresorbable stent that scaffolds the airway lumen and dissolves after the remodeling process is completed has advantages over metallic and silicone stents. We designed and fabricated a new mesh-type bioresorbable stent with a backbone of polycaprolactone (PCL), and evaluated its safety and biocompatibility in a rabbit trachea model. The PCL stent was fabricated by a laboratory-made microinjection molding machine. In vitro mechanical strength of the PCL stents was tested and compared to that of commercial silicone stents. The bioresorbable stents were surgically implanted into the cervical trachea of New Zealand white rabbits (n=6). Animals received bronchoscopic examination at 1, 2, 4, 8, and 12 weeks after surgery. Histological examination was completed to evaluate the biocompatibility of the stents. No animals died during the period of study. Distal stent migration was noted in 1 rabbit. In-stent secretion accumulation was found in 2 rabbits. Histological examination showed intact ciliated epithelium and marked leukocyte infiltration in the submucosa of the stented area at 10 and 28 weeks. Stent degradation was minimal, and the mechanical strength was well preserved at the end of 33 weeks. These preliminary findings showed good safety and biocompatibility of the new PCL stent when used in the airway remodeling. PCL could be a promising bioresorbable material for stent design if prolonged degradation time is required. Copyright © 2011 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

Stent-assisted recanalization of atherosclerotic intracranial stenosis

International Nuclear Information System (INIS)

Soo Mee Lim; Dae Chul Suh

2006-01-01

Intracranial atherosclerosis is a major cause of ischemic stroke, and depending on the studied population, it accounts for 8%-15% of all strokes that are due to cerebral atherosclerosis. The prognosis of patients with symptomatic intracranial stenoses seems to depend on the location and extent of intracranial atherosclerosis. Currently, the primary treatment in intracranial atherosclerosis is the control of vascular risk factors such as hypertension, diabetes, hypercholesterolemia, and smoking. Secondary prevention with antiplatelet therapy has been shown to reduce the risk of subsequent vascular events in patients who have suffered a recent ischemic stroke or transient ischemic attack (TIA). Unfortunately, a significant number of patients with intracranial atherosclerosis continue to suffer from repeated strokes or TIA despite maximal medical treatment. Although endovascular revascularization for symptomatic intracranial stenoses remains at the investigational stage and much of the pertinent information is anecdotal, intracranial angioplasty and stenting are being increasingly performed to treat stenotic lesions. This article reviews basic principles involved in the patient selection, premedication, angio-interventional procedures, angiographic and clinical results, periprocedural complication, patients aftercare. (authors)

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.)

Comparison of an everolimus-eluting bioresorbable scaffold with an everolimus-eluting metallic stent for the treatment of coronary artery stenosis (ABSORB II)

DEFF Research Database (Denmark)

Serruys, Patrick W; Chevalier, Bernard; Sotomi, Yohei

2016-01-01

BACKGROUND: No medium-term data are available on the random comparison between everolimus-eluting bioresorbable vascular scaffolds and everolimus-eluting metallic stents. The study aims to demonstrate two mechanistic properties of the bioresorbable scaffold: increase in luminal dimensions as a re...

Time-related changes in neointimal tissue coverage of a novel Sirolimus eluting stent

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Secco, Gioel Gabrio, E-mail: gioel.gabrio.secco@gmail.com [Interventional Cardiology, “Santi Antonio e Biagio e Cesare Arrigo” Hospital, Alessandria (Italy); NIHR Biomedical Research Unit, Royal Brompton & Harefield NHS Foundation Trust, London (United Kingdom); Mattesini, Alessio [NIHR Biomedical Research Unit, Royal Brompton & Harefield NHS Foundation Trust, London (United Kingdom); Fattori, Rossella; Parisi, Rosario [Interventional Cardiology, “San Salvatore” Hospital, Pesaro (Italy); Castriota, Fausto [GVM Care and Research, Cotignola (Italy); Vercellino, Matteo [Interventional Cardiology, “Santi Antonio e Biagio e Cesare Arrigo” Hospital, Alessandria (Italy); Dall’Ara, Gianni [NIHR Biomedical Research Unit, Royal Brompton & Harefield NHS Foundation Trust, London (United Kingdom); Uguccioni, Lucia; Marinucci, Lucia [Interventional Cardiology, “San Salvatore” Hospital, Pesaro (Italy); De Luca, Giuseppe; Marino, Paolo Nicola [University of Eastern Piedmont, Novara (Italy); Pistis, Gianfranco [Interventional Cardiology, “Santi Antonio e Biagio e Cesare Arrigo” Hospital, Alessandria (Italy); Di Mario, Carlo [NIHR Biomedical Research Unit, Royal Brompton & Harefield NHS Foundation Trust, London (United Kingdom)

2016-01-15

Background: DES has reduced rates of restenosis compared with BMS but it has been associated with delayed healing and increase of stent thrombosis. The aim of our study was to evaluate the vascular time-related changes following implantation of a new SES coated with an amorphous silicon carbide that allows faster re-endothelisation (Orsiro-Biotronik). Methods: This prospective registry enrolled STEMI-patients with multi-vessel disease, thus candidates for a two-step procedure. PCI of the culprit lesion was performed with at least one Orsiro stent that was OCT-analysed during the second-step procedure (deferred to 30,90 and 180-days). Results: 16 of the 95 patients with MVD underwent an OCT evaluation of the study device implanted in the culprit lesion during the second-step staged procedure and were enrolled in the present Registry. A total of 3060-struts were analysed. The percentage of uncovered struts was 19.6% at30-days, 1.3% at90-days and 1.8% at180-days (p < 0.001). The percentage of cross section with ≥ 1 uncovered struts were 51.3% at30-days, 6.5% at90-days and 5.7% at180-days (p < 0.001). The percentage of cross sections containing thrombus was 6.2% at30-days while no thrombus was detected both at90 and 180-days. Conclusions: Our data shows that the new Orsiro stent promotes early and persistent strut coverage with low peri-strut thrombus. This pilot OCT evaluation might suggest a low incidence of late adverse events and anticipate safe outcome after early withdrawal of dual antiplatelet therapy. - Highlights: • This is the first serial study comparing coverage at 1, 3, and 6-months in consecutive patients with STEMI; • Aim of our study was to evaluate the vascular time-related changes following implantation of a new SES coated with an amorphous silicon carbide that allows faster re-endothelisation (Orsiro-Biotronik); • The main finding of this pilot study is that the study device presented a fast pattern of intimal coverage, with a thin intimal

Feasibility and Safety of Transradial Arterial Approach for Simultaneous Right and Left Vertebral Artery Angiographic Studies and Stenting

International Nuclear Information System (INIS)

Yip, H.-K.; Youssef, Ali A.; Chang, W.-N.; Lu, C.-H.; Yang, C.-H.; Chen, S.-M.; Wu, C.-J.

2007-01-01

Objectives. This study investigated whether the transradial artery (TRA) approach using a 6-French (F) Kimny guiding catheter for right vertebral artery (VA) angiographic study and stenting is safe and effective for patients with significant VA stenosis. Background. The TRA approach is commonly performed worldwide for both diagnostic cardiac catheterization and catheter-based coronary intervention. However, to our knowledge, the safety and feasibility of left and right VA angiographic study and stenting, in the same procedure, using the TRA approach for patients with brain ischemia have not been reported. Methods. The study included 24 consecutive patients (22 male, 2 female; age, 63-78 years). Indications for VA angiographic study and stenting were (1) prior stroke or symptoms related to vertebrobasilar ischemia and (2) an asymptomatic but vertebral angiographic finding of severe stenosis (>70%). A combination of the ipsilateral and retrograde-engagement technique, which involved a looping 6-F Kimny guiding catheter, was utilized for VA angiographic study. For VA stenting, an ipsilateral TRA approach with either a Kimny guiding catheter or a left internal mammary artery guiding catheter was utilized in 22 patients and retrograde-engagement technique in 2 patients. Results. A technically successful procedure was achieved in all patients, including left VA stenting in 15 patients and right VA stenting in 9 patients. The mean time for stenting (from engagement to stent deployment) was 12.7 min. There were no vascular complications or mortality. However, one patient suffered from a transient ischemic attack that resolved within 3 h. Conclusion. We conclude that TRA access for both VA angiographic study and VA stenting is safe and effective, and provides a simple and useful clinical tool for patients unsuited for femoral arterial access

Results of a randomized clinical trial of external beam radiation to prevent restenosis after superficial femoral artery stenting.

Science.gov (United States)

Therasse, Eric; Donath, David; Elkouri, Stéphane; Lespérance, Jacques; Giroux, Marie-France; Oliva, Vincent L; Guertin, Marie-Claude; Bouchard, Louis; Perreault, Pierre; Gilbert, Patrick; Soulez, Gilles

2016-06-01

The objective of this study was to evaluate the safety and efficacy of external beam radiation (EBR) in preventing restenosis after superficial femoral artery (SFA) stenting in comparison with a control group treated with SFA stenting only. In this Institutional Review Board-approved study, patients who provided written informed consent were randomly assigned to 0 Gy or 14 Gy of EBR to the stent site 24 hours after SFA stenting. The primary end point was the angiographic binary restenosis rate 2 years after stenting. Categorical and continuous end points were respectively analyzed using logistic regression models and Wilcoxon tests. End points expressed as time to event were analyzed using a log-rank test. The study included 155 patients, 46 women and 109 men (mean age, 66 years; range, 45-85 years). In the 0 and 14 Gy groups, binary restenosis was present, respectively, in 44% (34/77) and 68% (52/76; P = .003) 2 years after stenting. Stent thrombosis occurred in 13% (10/78) of the 0 Gy group and in 33% (25/77) of the 14 Gy group (P = .003). Target lesion revascularization at 2 years was 26% (25/78) in the 0 Gy group and 30% (23/77) in the 14 Gy group (P = .56). There were no significant differences in total walking distances change from baseline to 2 years (46 ± 100 and 26 ± 79 m, respectively, in the 0 Gy and 14 Gy group; P = .25). There were no procedure-related deaths and no major amputations. A single 14 Gy dose of EBR to the SFA stenting site did not prevent in-stent restenosis. Copyright © 2016 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

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

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)

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

Science.gov (United States)

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

2017-09-01

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

Self-expanding stent-assisted middle cerebral artery recanalization: technical note

International Nuclear Information System (INIS)

Sauvageau, Eric; Levy, Elad I.

2006-01-01

Investigation into pharmacological and mechanical means of improving recanalization rates by intraarterial therapy has led to technological development. Angiographic recanalization has been associated with improvement in clinical outcome. A clot retriever has recently joined an imperfect armamentarium for intraarterial stroke therapy. In this report, we describe successful recanalization of an acute thrombotic occlusion of the inferior division of the middle cerebral artery (MCA) achieved with a self-expanding stent. An 82-year-old woman with a history of coronary atherosclerosis and previous cerebellar hemorrhage presented with a National Institutes of Health Stroke Scale (NIHSS) score of 11. Perfusion computed tomography imaging showed a left MCA territory deficit. Diffusion-weighted magnetic resonance (MR) imaging revealed a small punctiform insular hyperintensity. Angiography documented occlusion of the inferior division of the left MCA (Thrombolysis in Myocardial Infarction or Thrombolysis in Cerebral Infarction, TIMI/TICI, grade 0). Intraarterial delivery of eptifibatide to the occlusion site failed to recanalize the vessel. Deployment of a self-expanding stent in the occluded segment resulted in complete revascularization of the distal vascular bed. Angiography performed on the next day confirmed patency of the stented vessel segment (TIMI/TICI 3). The patient was discharged 3 days after the procedure (NIHSS 3). MR angiography obtained 3 months after the procedure documented left MCA patency. This technique may have a role worthy of further investigation in acute stroke therapy. (orig.)

Early outcomes after carotid angioplasty with stenting performed by neurologists

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Bathala Lokesh

2010-01-01

Full Text Available Aims: To evaluate the results of carotid artery angioplasty and stenting (CAS in treating extracranial carotid artery stenosis performed by neurologists in our center and compare the results with other large published series. Materials and Methods: Data for all patients who underwent CAS from January 2003 through November 2007, was retrieved from the Nanjing Stroke Registry. Perioperative and post-procedural complications within 30 days following stenting were analyzed and compared with that from other series. A total number of 75 patients were enrolled, with a mean age of 65.9 ± 8.8 years, and 64 (85.3% of them were male. Results: Procedural success was achieved in 74 patients (98.7%. Pre-treatment stenosis was 73.8 ± 14.9 and post-treatment residual stenosis was less than 10%. Thirty-four patients (45.3% had bilateral carotid artery disease and seven (9.3% had tandem stenosis. The neurological complication rate was 3.9% (one major and two minor strokes. Bradycardia in four (5.3% and hypotension in 13 (17.3% were observed during procedures. Using the Fischer′s exact t test, the complication rate compared with the large published series did not reveal any statistically significant difference (P > 0.05. Conclusions: We conclude that neurologists, with adequate training, can develop and add this technical skill to the existing cognitive skill of vascular neurology and safely perform stenting.

Evaluation of magnesium-yttrium alloy as an extraluminal tracheal stent.

Science.gov (United States)

Luffy, Sarah A; Chou, Da-Tren; Waterman, Jenora; Wearden, Peter D; Kumta, Prashant N; Gilbert, Thomas W

2014-03-01

Tracheomalacia is a relatively rare problem, but can be challenging to treat, particularly in pediatric patients. Due to the presence of mechanically deficient cartilage, the trachea is unable to resist collapse under physiologic pressures of respiration, which can lead to acute death if left untreated. However, if treated, the outcome for patients with congenital tracheomalacia is quite good because the cartilage tends to spontaneously mature over a period of 12 to 18 months. The present study investigated the potential for the use of degradable magnesium-3% yttrium alloy (W3) to serve as an extraluminal tracheal stent in a canine model. The host response to the scaffold included the formation of a thin, vascularized capsule consisting of collagenous tissue and primarily mononuclear cells. The adjacent cartilage structure was not adversely affected as observed by bronchoscopic, gross, histologic, and mechanical analysis. The W3 stents showed reproducible spatial and temporal fracture patterns, but otherwise tended to corrode quite slowly, with a mix of Ca and P rich corrosion product formed on the surface and observed focal regions of pitting. The study showed that the approach to use degradable magnesium alloys as an extraluminal tracheal stent is promising, although further development of the alloys is required to improve the resistance to stress corrosion cracking and improve the ductility. Copyright © 2013 Wiley Periodicals, Inc.

Development of an abdominal aortic aneurysm model for stent-graft insertion

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Kim, Tae Hyung; Lee, Jong Heon; Shin, Dong Ik; Sung, Kyu Bo; Ko, Gi Young; Lim, Jin Oh [College of Medicine, Univ. of Ulsan, Seoul (Korea, Republic of); Kim, Si Hoon [S and G Biotech Research Institute, Seoul (Korea, Republic of)

2002-03-01

To determine the efficacy of an abdominal aortic aneurysm model for stent-graft placement. The model consists of two parts, the heart and the vascular system. A peristaltic pump and a solenoid valve were used to simulate a pulsatile flow from the heart. A ball-shaped piece of clay was placed inside a square box and liquid silicone was poured. After the silicone was formed, the clay was removed and a silicone tube was used to connect the heart model and the aneurysm model. The silicone tube was also used to simulate the iliac arteries and one end of the artery was clampled and the other one was extended to water bath. Water at 37 .deg. C was circulated through the model, and the pressure at the thoracic aorta, aneurysm and iliac artery was measured with the outlet valve opening at 25, 50, and 100% before and after stent-graft placement. The liquid pressure measurements were 253/252, 271/162 and 264/166 mmHg at the thoracic aorta, aneurysm and iliac artery, respectively, when the outlet was 100% open. They were 173/121, 145/99, 145/106 mmHg when the outlet was 50% open, and 35/28, 61/44, 24/22 mmHg when it was 25% open. After placement of the stent-graft, the pressure measurements were 170/128, and 167/128 mmHg, respectively. Since it was easy to produce, the model was useful for in-vitro stent-graft testing, and a wide range of pressure could be applied.

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

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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.

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.

In vitro performance investigation of bioresorbable scaffolds – Standard tests for vascular stents and beyond

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Schmidt, Wolfram, E-mail: wolfram.schmidt@uni-rostock.de [Institute for Biomedical Engineering, University Medicine Rostock, Friedrich-Barnewitz-Strasse 4, D-18119 Rostock-Warnemünde (Germany); Behrens, Peter, E-mail: peter.behrens@uni-rostock.de [Institute for Biomedical Engineering, University Medicine Rostock, Friedrich-Barnewitz-Strasse 4, D-18119 Rostock-Warnemünde (Germany); Brandt-Wunderlich, Christoph, E-mail: christoph.brandt@uni-rostock.de [Institute for ImplantTechnology and Biomaterials – IIB e.V., Associated Institute of the University of Rostock, Friedrich-Barnewitz-Strasse 4, D-18119 Rostock-Warnemünde (Germany); Siewert, Stefan, E-mail: stefan.siewert@uni-rostock.de [Institute for ImplantTechnology and Biomaterials – IIB e.V., Associated Institute of the University of Rostock, Friedrich-Barnewitz-Strasse 4, D-18119 Rostock-Warnemünde (Germany); Grabow, Niels, E-mail: niels.grabow@uni-rostock.de [Institute for Biomedical Engineering, University Medicine Rostock, Friedrich-Barnewitz-Strasse 4, D-18119 Rostock-Warnemünde (Germany); Schmitz, Klaus-Peter, E-mail: klaus-peter.schmitz@uni-rostock.de [Institute for ImplantTechnology and Biomaterials – IIB e.V., Associated Institute of the University of Rostock, Friedrich-Barnewitz-Strasse 4, D-18119 Rostock-Warnemünde (Germany)

2016-09-15

Background/Purpose: Biodegradable polymers are the main materials for coronary scaffolds. Magnesium has been investigated as a potential alternative and was successfully tested in human clinical trials. However, it is still challenging to achieve mechanical parameters comparative to permanent bare metal (BMS) and drug-eluting stents (DES). As such, in vitro tests are required to assess mechanical parameters correlated to the safety and efficacy of the device. Methods/Materials: In vitro bench tests evaluate scaffold profiles, length, deliverability, expansion behavior including acute elastic and time-dependent recoil, bending stiffness and radial strength. The Absorb GT1 (Abbott Vascular, Temecula, CA), DESolve (Elixir Medical Corporation, Sunnyvale, CA) and the Magmaris (BIOTRONIK AG, Bülach, Switzerland) that was previously tested in the BIOSOLVE II study, were tested. Results: Crimped profiles were 1.38 ± 0.01 mm (Absorb GT1), 1.39 ± 0.01 mm (DESolve) and 1.44 ± 0.00 mm (Magmaris) enabling 6F compatibility. Trackability was measured depending on stiffness and force transmission (pushability). Acute elastic recoil was measured at free expansion and within a mock vessel, respectively, yielding results of 5.86 ± 0.76 and 5.22 ± 0.38% (Absorb), 7.85 ± 3.45 and 9.42 ± 0.21% (DESolve) and 5.57 ± 0.72 and 4.94 ± 0.31% (Magmaris). Time-dependent recoil (after 1 h) was observed for the Absorb and DESolve scaffolds but not for the Magmaris. The self-correcting wall apposition behavior of the DESolve did not prevent time-dependent recoil under vessel loading. Conclusions: The results of the suggested test methods allow assessment of technical feasibility based on objective mechanical data and highlight the main differences between polymeric and metallic bioresorbable scaffolds.

In vitro performance investigation of bioresorbable scaffolds – Standard tests for vascular stents and beyond

International Nuclear Information System (INIS)

Schmidt, Wolfram; Behrens, Peter; Brandt-Wunderlich, Christoph; Siewert, Stefan; Grabow, Niels; Schmitz, Klaus-Peter

2016-01-01

Background/Purpose: Biodegradable polymers are the main materials for coronary scaffolds. Magnesium has been investigated as a potential alternative and was successfully tested in human clinical trials. However, it is still challenging to achieve mechanical parameters comparative to permanent bare metal (BMS) and drug-eluting stents (DES). As such, in vitro tests are required to assess mechanical parameters correlated to the safety and efficacy of the device. Methods/Materials: In vitro bench tests evaluate scaffold profiles, length, deliverability, expansion behavior including acute elastic and time-dependent recoil, bending stiffness and radial strength. The Absorb GT1 (Abbott Vascular, Temecula, CA), DESolve (Elixir Medical Corporation, Sunnyvale, CA) and the Magmaris (BIOTRONIK AG, Bülach, Switzerland) that was previously tested in the BIOSOLVE II study, were tested. Results: Crimped profiles were 1.38 ± 0.01 mm (Absorb GT1), 1.39 ± 0.01 mm (DESolve) and 1.44 ± 0.00 mm (Magmaris) enabling 6F compatibility. Trackability was measured depending on stiffness and force transmission (pushability). Acute elastic recoil was measured at free expansion and within a mock vessel, respectively, yielding results of 5.86 ± 0.76 and 5.22 ± 0.38% (Absorb), 7.85 ± 3.45 and 9.42 ± 0.21% (DESolve) and 5.57 ± 0.72 and 4.94 ± 0.31% (Magmaris). Time-dependent recoil (after 1 h) was observed for the Absorb and DESolve scaffolds but not for the Magmaris. The self-correcting wall apposition behavior of the DESolve did not prevent time-dependent recoil under vessel loading. Conclusions: The results of the suggested test methods allow assessment of technical feasibility based on objective mechanical data and highlight the main differences between polymeric and metallic bioresorbable scaffolds.

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

Heparin surface stent-graft for the treatment of a carotid pseudoaneurysm.

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Tsolaki, Elpiniki; Elpiniki, Tsolaki; Salviato, Elisabetta; Rocca, Tiberio; Braccini, Lucia; Galeotti, Roberto; Mascoli, Francesco

2010-10-01

Carotid pseudoaneurysms are a rare consequence of carotid surgery, trauma, and infection. Historically, carotid aneurysms and pseudoaneurysms were treated surgically. However, endovascular techniques have recently become a valid alternative for the treatment of carotid pseudoaneurysms. The case of a 57-year-old male patient with a pseudoaneurysm of the right internal carotid artery is described. The patient came to our unit with a painless and pulsatile mass in the neck, which was growing slowly. Five years earlier, he had undergone surgery on a saccular aneurysm located on the distal extracranial segment of the right internal carotid artery. The pseudoaneurysm was successfully treated with a heparin surface Viabahn stent-graft system (Gore AL, Flagstaff, AZ). Heparin surface stent-grafts can be used for the treatment of carotid lesions and may offer protection against intimal hyperplasia and thrombosis. Further studies are needed to evaluate the long-term results. Copyright © 2010 Annals of Vascular Surgery Inc. Published by Elsevier Inc. All rights reserved.

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

Science.gov (United States)

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

2005-08-01

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

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

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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 

Beyond Oncogenesis: The Role of S-Phase Kinase-Associated Protein-2 (SKP2 In Vascular Restenosis

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Yih-Jer Wu

2008-12-01

Full Text Available The clinical benefits of percutaneous coronary intervention, the most prevalent procedure nowadays for the treatment of symptomatic coronary artery disease, are frequently offset by the occurrence of vascular restenosis. Although the introduction of drug-eluting stents has significantly reduced restenotic rates, the rare, but potentially fatal, delayed thrombosis remains a clinical threat. Further refinement of the drug-eluting stent based on a better understanding of cell cycle regulation between the vascular smooth muscle cell (VSMC and endothelial cell (EC is required. In this review, we discuss the role of S-phase kinase-associated protein-2 (Skp2, previously known as an oncoprotein, in the regulation of VSMC proliferation and its signaling axis. The currently available evidence suggests that the Rac1-Skp2-p27Kip1 signaling axis acts as a common final pathway for many factors that regulate VSMC proliferation, such as growth factors, extracellular matrices and cyclic nucleotides. Importantly, although EC proliferation is also shown to be regulated by the same axis, cAMP seems to regulate this axis differentially between VSMC and EC, rendering the underlying mechanism of this differential regulation a promising target for the development of a new generation of drug-eluting stent.

The value of primary vascular stents in management of early portal vein stenosis after liver transplantation

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Wen-Tsan Chang

2016-03-01

Full Text Available If portal vein stenosis (PVS occurs within 1 month after liver transplantation (LT, especially within 1 week, it can be catastrophic and result in rapid loss of the grafts and mortality. Although surgical treatments have been considered standard treatment for PVS, patients are usually unable to receive operations or re-transplantations, because of their critical conditions and a shortage of grafts. Recently, primary percutaneous transhepatic portal vein stents (PTPS were suggested as alternative and less-invasive treatments of PVS. However, because lethal complications may follow these primary stent placements for patients in early stages after LT, primary PTPS placements for patients suffering PVS 1 month after LT has been suggested. From November 2009 to July 2015, 38 consecutive adult patients underwent LT at our institution. Among them, six recipients suffered PVS within 1 month after LT. Technical success was achieved in all six patients. Clinical success was obtained in two of the four patients suffering PVS within 1 week after LT, and in the other two patients suffering PVS>1 week after LT. All surviving patients and their grafts were in good condition, and their stents remained patent. Our experience showed that primary PTPS placements can be used to effectively treat patients with PVS encountered within 1 month, and even within 1 week, after LT with acceptable short-term results. However, possible fatal complications should be kept in mind. Long-term results of these procedures need further follow-up.

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.

Selective Inhibitory Effect of Epigallocatechin-3-gallate on Migration of Vascular Smooth Muscle Cells

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Jong-Chul Park

2010-11-01

Full Text Available In order to prevent restenosis after angioplasty or stenting, one of the most popular targets is suppression of the abnormal growth and excess migration of vascular smooth muscle cells (VSMCs with drugs. However, the drugs also adversely affect vascular endothelial cells (VECs, leading to the induction of late thrombosis. We have investigated the effect of epigallocatechin-3-gallate (EGCG on the proliferation and migration of VECs and VSMCs. Both cells showed dose-dependent decrease of viability in response to EGCG while they have different IC50 values of EGCG (VECs, 150 mM and VSMCs, 1050 mM. Incubating both cells with EGCG resulted in significant reduction in cell proliferation irrespective of cell type. The proliferation of VECs were greater affected than that of VSMCs at the same concentrations of EGCG. EGCG exerted differential migration-inhibitory activity in VECs vs. VSMCs. The migration of VECs was not attenuated by 200 mM EGCG, but that of VSMCs was significantly inhibited at the same concentration of EGCG. It is suggested that that EGCG can be effectively used as an efficient drug for vascular diseases or stents due to its selective activity, completely suppressing the proliferation and migration of VSMCs, but not adversely affecting VECs migration in blood vessels.

[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.

Direct comparison of coronary bare metal vs. drug-eluting stents: same platform, different mechanics?

Science.gov (United States)

Schmidt, Wolfram; Lanzer, Peter; Behrens, Peter; Brandt-Wunderlich, Christoph; Öner, Alper; Ince, Hüseyin; Schmitz, Klaus-Peter; Grabow, Niels

2018-01-08

Drug-eluting stents (DES) compared to bare metal stents (BMS) have shown superior clinical performance, but are considered less suitable in complex cases. Most studies do not distinguish between DES and BMS with respect to their mechanical performance. The objective was to obtain mechanical parameters for direct comparison of BMS and DES. In vitro bench tests evaluated crimped stent profiles, crossability in stenosis models, elastic recoil, bending stiffness (crimped and expanded), and scaffolding properties. The study included five pairs of BMS and DES each with the same stent platforms (all n = 5; PRO-Kinetic Energy, Orsiro: BIOTRONIK AG, Bülach, Switzerland; MULTI-LINK 8, XIENCE Xpedition: Abbott Vascular, Temecula, CA; REBEL Monorail, Promus PREMIER, Boston Scientific, Marlborough, MA; Integrity, Resolute Integrity, Medtronic, Minneapolis, MN; Kaname, Ultimaster: Terumo Corporation, Tokyo, Japan). Statistical analysis used pooled variance t tests for pairwise comparison of BMS with DES. Crimped profiles in BMS groups ranged from 0.97 ± 0.01 mm (PRO-Kinetic Energy) to 1.13 ± 0.01 mm (Kaname) and in DES groups from 1.02 ± 0.01 mm (Orsiro) to 1.13 ± 0.01 mm (Ultimaster). Crossability was best for low profile stent systems. Elastic recoil ranged from 4.07 ± 0.22% (Orsiro) to 5.87 ± 0.54% (REBEL Monorail) including both BMS and DES. The bending stiffness of crimped and expanded stents showed no systematic differences between BMS and DES neither did the scaffolding. Based on in vitro measurements BMS appear superior to DES in some aspects of mechanical performance, yet the differences are small and not class uniform. The data provide assistance in selecting the optimal system for treatment and assessment of new generations of bioresorbable scaffolds. not applicable.

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.

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...

Endovascular treatment of intrahepatic inferior vena cava obstruction from malignant hepatocellular tumor thrombus utilizing Luminexx self-expanding nitinol stents

International Nuclear Information System (INIS)

Stambo, Glenn W.; Leto, John; George, Christopher; Van Epps, Kelly; Woeste, Troy; Berlet, Mathew

2008-01-01

Inferior vena cava (IVC) obstruction is a well-described clinical entity. Most IVC obstructions from malignant neoplasms are a direct result of tumor compression [Oviedo J, Cerda S. Vascular invasion by hepatocellular carcinoma. Arch Pathol Lab Med 2001;125: 454-5; Furui S, Sawada S, et al. Gianturco stent placement in malignant caval obstruction: analysis of factors for predicting the outcome. Radiology 1995;195:147-52; Fletcher WS, Lakin PC, et al. Results of treatment of inferior vena cava syndrome with expandable metallic stents. Arch Surg 1998;133:935-8]. The symptoms of IVC obstruction include progressive ascites, scrotal edema and lower body edema. These constellations of symptoms are described as IVC syndrome and are devastating to a patient with end-stage cancer. We describe a palliative therapy utilizing Luminexx nitinol self-expanding stents to treat intracaval hepatoma thrombus obstructing the IVC. The procedure is rapidly performed, technically reliable, and has essentially no morbidity or mortality. This procedure can be performed in the interventional radiology suite with excellent results resolving the IVC syndrome soon after placement of the stents. We believe endovascular stenting as an excellent palliative therapy for patients with IVC syndrome and should be the treatment of choice for caval obstructions due to intraluminal tumor thrombus

Endovascular treatment of intrahepatic inferior vena cava obstruction from malignant hepatocellular tumor thrombus utilizing Luminexx self-expanding nitinol stents

Energy Technology Data Exchange (ETDEWEB)

Stambo, Glenn W. [Division of Vascular and Interventional Radiology, Department of Radiology, St. Joseph' s Hospital and Medical Center, 4516 North Armenia Avenue, Tampa, FL 33603 (United States)], E-mail: xraydoc2@yahoo.com; Leto, John [Division of Vascular and Interventional Radiology, Department of Radiology, St. Joseph' s Hospital and Medical Center, 3001 W. Dr. Martin Luther King Jr. Blvd., Tampa, FL 33607 (United States); George, Christopher [Department of Hematology and Oncology, St. Joseph' s Hospital and Medical Center, 4301 W. Habana Avenue, Suite 1, Tampa, FL 33607 (United States); Van Epps, Kelly; Woeste, Troy; Berlet, Mathew [Division of Vascular and Interventional Radiology, Department of Radiology, St. Joseph' s Hospital and Medical Center, 4516 North Armenia Avenue, Tampa, FL 33603 (United States)

2008-05-15

Inferior vena cava (IVC) obstruction is a well-described clinical entity. Most IVC obstructions from malignant neoplasms are a direct result of tumor compression [Oviedo J, Cerda S. Vascular invasion by hepatocellular carcinoma. Arch Pathol Lab Med 2001;125: 454-5; Furui S, Sawada S, et al. Gianturco stent placement in malignant caval obstruction: analysis of factors for predicting the outcome. Radiology 1995;195:147-52; Fletcher WS, Lakin PC, et al. Results of treatment of inferior vena cava syndrome with expandable metallic stents. Arch Surg 1998;133:935-8]. The symptoms of IVC obstruction include progressive ascites, scrotal edema and lower body edema. These constellations of symptoms are described as IVC syndrome and are devastating to a patient with end-stage cancer. We describe a palliative therapy utilizing Luminexx nitinol self-expanding stents to treat intracaval hepatoma thrombus obstructing the IVC. The procedure is rapidly performed, technically reliable, and has essentially no morbidity or mortality. This procedure can be performed in the interventional radiology suite with excellent results resolving the IVC syndrome soon after placement of the stents. We believe endovascular stenting as an excellent palliative therapy for patients with IVC syndrome and should be the treatment of choice for caval obstructions due to intraluminal tumor thrombus.

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.

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

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

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.

A multimodality vascular imaging phantom of an abdominal aortic aneurysm with a visible thrombus

Energy Technology Data Exchange (ETDEWEB)

Allard, Louise; Chayer, Boris; Qin Zhao [Laboratory of Biorheology and Medical Ultrasonics, Research Center, University of Montreal Hospital (CRCHUM), Quebec H2L 2W5 (Canada); Soulez, Gilles [Department of Radiology, University of Montreal Hospital (CHUM), Quebec H2L 2M1 (Canada); Department of Radiology, Radio-Oncology and Nuclear Medicine, University of Montreal, Quebec H3T 1J4 (Canada); Institute of Biomedical Engineering, University of Montreal, Quebec H3T 1J4 (Canada); Roy, David [Institute of Biomedical Engineering, University of Montreal, Quebec H3T 1J4 (Canada); Cloutier, Guy [Laboratory of Biorheology and Medical Ultrasonics, Research Center, University of Montreal Hospital (CRCHUM), Quebec H2L 2W5 (Canada); Department of Radiology, Radio-Oncology and Nuclear Medicine, University of Montreal, Quebec H3T 1J4 (Canada); Institute of Biomedical Engineering, University of Montreal, Quebec H3T 1J4 (Canada)

2013-06-15

Purpose: With the continuous development of new stent grafts and implantation techniques, it has now become technically feasible to treat abdominal aortic aneurysms (AAA) with challenging anatomy using endovascular repair with standard, fenestrated, or branched stent-grafts. In vitro experimentations are very useful to improve stent-graft design and conformability or imaging guidance for stent-graft delivery or follow-up. Vascular replicas also help to better understand the limitation of endovascular approaches in challenging anatomy and possibly improve surgical planning or training by practicing high risk clinical procedures in the laboratory to improve outcomes in the operating room. Most AAA phantoms available have a very basic anatomy, which is not representative of the clinical reality. This paper presents a method of fabrication of a realistic AAA phantom with a visible thrombus, as well as some mechanical properties characterizing such phantom. Methods: A realistic AAA geometry replica of a real patient anatomy taken from a multidetector computed tomography (CT) scan was manufactured. To demonstrate the multimodality imaging capability of this new phantom with a thrombus visible in magnetic resonance (MR) angiography, CT angiography (CTA), digital subtraction angiography (DSA), and ultrasound, image acquisitions with all these modalities were performed by using standard clinical protocols. Potential use of this phantom for stent deployment was also tested. A rheometer allowed defining hyperelastic and viscoelastic properties of phantom materials. Results: MR imaging measurements of SNR and CNR values on T1 and T2-weighted sequences and MR angiography indicated reasonable agreement with published values of AAA thrombus and abdominal components in vivo. X-ray absorption also lay within normal ranges of AAA patients and was representative of findings observed on CTA, fluoroscopy, and DSA. Ultrasound propagation speeds for developed materials were also in

A multimodality vascular imaging phantom of an abdominal aortic aneurysm with a visible thrombus

International Nuclear Information System (INIS)

Allard, Louise; Chayer, Boris; Qin Zhao; Soulez, Gilles; Roy, David; Cloutier, Guy

2013-01-01

Purpose: With the continuous development of new stent grafts and implantation techniques, it has now become technically feasible to treat abdominal aortic aneurysms (AAA) with challenging anatomy using endovascular repair with standard, fenestrated, or branched stent-grafts. In vitro experimentations are very useful to improve stent-graft design and conformability or imaging guidance for stent-graft delivery or follow-up. Vascular replicas also help to better understand the limitation of endovascular approaches in challenging anatomy and possibly improve surgical planning or training by practicing high risk clinical procedures in the laboratory to improve outcomes in the operating room. Most AAA phantoms available have a very basic anatomy, which is not representative of the clinical reality. This paper presents a method of fabrication of a realistic AAA phantom with a visible thrombus, as well as some mechanical properties characterizing such phantom. Methods: A realistic AAA geometry replica of a real patient anatomy taken from a multidetector computed tomography (CT) scan was manufactured. To demonstrate the multimodality imaging capability of this new phantom with a thrombus visible in magnetic resonance (MR) angiography, CT angiography (CTA), digital subtraction angiography (DSA), and ultrasound, image acquisitions with all these modalities were performed by using standard clinical protocols. Potential use of this phantom for stent deployment was also tested. A rheometer allowed defining hyperelastic and viscoelastic properties of phantom materials. Results: MR imaging measurements of SNR and CNR values on T1 and T2-weighted sequences and MR angiography indicated reasonable agreement with published values of AAA thrombus and abdominal components in vivo. X-ray absorption also lay within normal ranges of AAA patients and was representative of findings observed on CTA, fluoroscopy, and DSA. Ultrasound propagation speeds for developed materials were also in

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.)

Bioerodible drug/eluting stent coating with highly controllable drug release rate and excellent vascular biocompatibility

Czech Academy of Sciences Publication Activity Database

Rypáček, František; Mulinková, Katarína; Bernátková, Markéta; Machová, Luďka; Lapčíková, Monika; Otsuka, Y.; Robinson, K. A.; Mulkey, S. P.; Baranowski, C.; Zablocki, J.; Blackburn, B. K.; Chronos, N.

2005-01-01

Roč. 96, 7A (2005), 209H-210H ISSN 0002-9149. [Annual Conference of Transcathetral Cardiovascular Therapeutics /17./. Washington, 16.10.2005-21.10.2005] R&D Projects: GA AV ČR IAA4050202 Institutional research plan: CEZ:AV0Z40500505 Keywords : drug delivery * polymer coating * stent Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.059, year: 2005

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

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)

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.

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.

[Numerical simulation of the effect of virtual stent release pose on the expansion results].

Science.gov (United States)

Li, Jing; Peng, Kun; Cui, Xinyang; Fu, Wenyu; Qiao, Aike

2018-04-01

The current finite element analysis of vascular stent expansion does not take into account the effect of the stent release pose on the expansion results. In this study, stent and vessel model were established by Pro/E. Five kinds of finite element assembly models were constructed by ABAQUS, including 0 degree without eccentricity model, 3 degree without eccentricity model, 5 degree without eccentricity model, 0 degree axial eccentricity model and 0 degree radial eccentricity model. These models were divided into two groups of experiments for numerical simulation with respect to angle and eccentricity. The mechanical parameters such as foreshortening rate, radial recoil rate and dog boning rate were calculated. The influence of angle and eccentricity on the numerical simulation was obtained by comparative analysis. Calculation results showed that the residual stenosis rates were 38.3%, 38.4%, 38.4%, 35.7% and 38.2% respectively for the 5 models. The results indicate that the pose has less effect on the numerical simulation results so that it can be neglected when the accuracy of the result is not highly required, and the basic model as 0 degree without eccentricity model is feasible for numerical simulation.

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.

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)

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.

Plastic strains during stent deployment have a critical influence on the rate of corrosion in absorbable magnesium stents.

Science.gov (United States)

Galvin, Emmet; Cummins, Christy; Yoshihara, Shoichiro; Mac Donald, Bryan J; Lally, Caitríona

2017-08-01

Magnesium stents are a promising candidate in the emerging field of absorbable metallic stents (AMSs). In this study, the mechanical and corrosion performance of dog-bone specimens and a specific stent design of a magnesium alloy, WE43, are assessed experimentally in terms of their corrosion behaviour and mechanical integrity. It is shown that plastic strains that are induced in the struts of the stent during stent deployment have a critical influence in directing subsequent corrosion behaviour within the material. In addition, the deployment and scaffolding characteristics of the magnesium stent are elucidated and contrasted with those of a commercial stainless steel stent. The magnesium stent is found to support higher levels of cyclic strain amplitude than the stainless steel stent, even prior to degradation, and this may play a role in reducing in-stent restenosis. This study provides new insights into the experimental performance of a current AMS design and material whilst demonstrating the critical influence of plastic strain on the corrosion performance and scaffolding ability of an AMS.

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...

Carotid angioplasty and stenting in the elderly

International Nuclear Information System (INIS)

Kadkhodayan, Yasha; Cross, DeWitte T.; Moran, Christopher J.; Derdeyn, Colin P.

2007-01-01

To investigate the technical success rate as well as the procedural and mid-term complication rates of carotid angioplasty and stenting in elderly patients, a group excluded from large randomized endarterectomy trials given their perceived high surgical risk. Of 200 consecutive carotid angioplasty and/or stenting procedures performed between March 1996 and March 2005, 21 procedures were performed without cerebral protection devices in 20 patients over the age of 79 years (mean age: 83 years, 12 men, eight women). These patients' medical records were retrospectively reviewed for vascular imaging reports and available clinical follow-up. Procedural and mid-term complication rates were calculated and compared to a previously published cohort of 133 consecutive patients ≤79 years of age who also underwent endovascular treatment at our institution. Carotid stenosis was reduced from a mean of 82% to no significant stenosis in all procedures. The procedural stroke rate was zero of 21 procedures. The procedural transient ischemic attack rate (TIA) was one of 21 procedures (4.8%). Mean follow-up was 24.6 months (range: 1.0-79.5 months) with at least a 30-day follow-up for 20 of the 21 procedures (95.2%). There were no new strokes. There was one recurrent ipsilateral TIA at 1.9 months. In five cases with follow-up carotid ultrasonography, no hemodynamically significant restenosis had occurred. There were three myocardial infarctions (MI) occurring at 0.5, 2.1, and 15.2 months, of which the last MI was fatal. The composite 30-day stroke and death rate was zero of 21 procedures (95% confidence interval: 0-14%). No significant difference was found in the 30-day rate of stroke, TIA, MI, or death between the elderly and younger patients. Carotid angioplasty and stenting in elderly patients can be performed successfully with acceptable procedural and mid-term complication rates comparable to younger patients. (orig.)

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.

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...

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.

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

Carotid angioplasty and stent placement for restenosis after endarterectomy

International Nuclear Information System (INIS)

Kadkhodayan, Yasha; Moran, Christopher J.; Cross, DeWitte T.; Derdeyn, Colin P.

2007-01-01

Recurrent carotid stenosis following endarterectomy is a common complication, and reoperation may be associated with increased morbidity. The goal of this study was to determine the procedural safety and long-term complication rates of carotid angioplasty and stenting for recurrent stenosis. Of 248 consecutive carotid angioplasty and/or stenting procedures performed at our institution between March 1996 and November 2005, 83 procedures for recurrent stenosis following endarterectomy were performed in 75 patients (mean age 68 years; 43 men, 32 women) without cerebral protection devices. The patients' medical records were retrospectively reviewed for vascular imaging reports and available clinical follow-up. Procedural and long-term complication rates were calculated. Recurrent stenosis was reduced from a mean of 80.6% to no significant stenosis in 82 of 83 procedures. The procedural stroke rate was 3 out of 83 procedures (3.6%). The procedural transient ischemic attack (TIA) rate was 2 out of 83 procedures (2.4%). Mean follow-up was 22.4 months (range 0.1 to 86.7 months) with at least 6 months follow-up for 54 of 83 procedures (65%). There were five TIAs and no strokes on follow-up (new TIAs at 25.5 and 43.4 months; recurrent TIAs at 1, 11.1, and 12 months, all with normal angiograms). The composite 30-day stroke, myocardial infarction, or death rate was 5 of 83 procedures (6.0%). In this series, angioplasty and stenting were effective in relieving stenosis secondary to recurrent carotid disease after endarterectomy, and have low rates of ischemic complications. (orig.)

Local sustained delivery of acetylsalicylic acid via hybrid stent with biodegradable nanofibers reduces adhesion of blood cells and promotes reendothelialization of the denuded artery

Directory of Open Access Journals (Sweden)

Lee CH

2014-01-01

Full Text Available Cheng-Hung Lee,1,2 Yu-Huang Lin,3 Shang-Hung Chang,1 Chun-Der Tai,3 Shih-Jung Liu,2 Yen Chu,4 Chao-Jan Wang,5 Ming-Yi Hsu,5 Hung Chang,6 Gwo-Jyh Chang,7 Kuo-Chun Hung,1 Ming-Jer Hsieh,1 Fen-Chiung Lin,1 I-Chang Hsieh,1 Ming-Shien Wen,1 Yenlin Huang81Division of Cardiology, Department of Internal Medicine, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Linkou, 2Department of Mechanical Engineering, 3Graduate Institute of Medical Mechatronics, Chang Gung University, 4Laboratory of Cardiovascular Physiology, Division of Thoracic and Cardiovascular Surgery, 5Department of Medical Imaging and Intervention, 6Hematology-Oncology Division, Department of Internal Medicine, Chang Gung Memorial Hospital, Linkou, 7Graduate Institute of Clinical Medicinal Sciences, Chang Gung University College of Medicine, Linkou, 8Department of Anatomical Pathology, Chang Gung Memorial Hospital, Linkou, Tao-Yuan, TaiwanAbstract: Incomplete endothelialization, blood cell adhesion to vascular stents, and inflammation of arteries can result in acute stent thromboses. The systemic administration of acetylsalicylic acid decreases endothelial dysfunction, potentially reducing thrombus, enhancing vasodilatation, and inhibiting the progression of atherosclerosis; but, this is weakened by upper gastrointestinal bleeding. This study proposes a hybrid stent with biodegradable nanofibers, for the local, sustained delivery of acetylsalicylic acid to injured artery walls. Biodegradable nanofibers are prepared by first dissolving poly(D,L-lactide-co-glycolide and acetylsalicylic acid in 1,1,1,3,3,3-hexafluoro-2-propanol. The solution is then electrospun into nanofibrous tubes, which are then mounted onto commercially available bare-metal stents. In vitro release rates of pharmaceuticals from nanofibers are characterized using an elution method, and a high-performance liquid chromatography assay. The experimental results suggest that biodegradable nanofibers

[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.

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.

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

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

2017-08-01

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

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

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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.

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

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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

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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.

Endovascular Treatment of Descending Thoracic Aortic Aneurysms with the EndoFit Stent-Graft

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Saratzis, N.; Saratzis, Athanasios; Melas, N.; Ginis, G.; Lioupis, A.; Lykopoulos, D.; Lazaridis, J.; Kiskinis, Dimitrios

2007-01-01

Objective. To evaluate the mid-term feasibility, efficacy, and durability of descending thoracic aortic aneurysm (DTAA) exclusion using the EndoFit device (LeMaitre Vascular). Methods. Twenty-three (23) men (mean age 66 years) with a DTAA were admitted to our department for endovascular repair (21 were ASA III+ and 2 refused open repair) from January 2003 to July 2005. Results. Complete aneurysm exclusion was feasible in all subjects (100% technical success). The median follow-up was 18 months (range 8-40 months). A single stent-graft was used in 6 cases. The deployment of a second stent-graft was required in the remaining 17 patients. All endografts were attached proximally, beyond the left subclavian artery, leaving the aortic arch branches intact. No procedure-related deaths have occurred. A distal type I endoleak was detected in 2 cases on the 1 month follow-up CT scan, and was repaired with reintervention and deployment of an extension graft. A nonfatal acute myocardial infarction occurred in 1 patient in the sixth postoperative month. Graft migration, graft infection, paraplegia, cerebral or distal embolization, renal impairment or any other major complications were not observed. Conclusion. The treatment of DTAAs using the EndoFit stent-graft is technically feasible. Mid-term results in this series are promising

The (PrS/HGF-pDNA) multilayer films for gene-eluting stent coating: Gene-protecting, anticoagulation, antibacterial properties, and in vivo antirestenosis evaluation.

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Chang, Hao; Ren, Ke-feng; Zhang, He; Wang, Jin-lei; Wang, Bai-liang; Ji, Jian

2015-02-01

Vascular gene-eluting stents (GES) is a promising strategy for treatment of cardiovascular disease. Very recently, we have proved that the (protamine sulfate/plasmid DNA encoding hepatocyte growth factor) (PrS/HGF-pDNA) multilayer can serve as a powerful tool for enhancing competitiveness of endothelial cell over smooth muscle cell, which opens perspectives for the regulation of intercellular competitiveness in the field of interventional therapy. However, before the gene multilayer films could be used in vascular stents for real clinical application, the preservation of gene bioactivity during the industrial sterilization and the hemocompatibility of film should be taken into account. Actually, both are long been ignored issues in the field of gene coating for GES. In this study, we demonstrate that the (PrS/HGF-pDNA) multilayer film exhibits the good gene-protecting abilities, which is confirmed by using the industrial sterilizations (gamma irradiation and ethylene oxide) and a routine storage condition (dry state at 4°C for 30 days). Furthermore, hemocompatible measurements (such as platelet adhesion and whole blood coagulation) and antibacterial assays (bacteria adhesion and growth inhibition) indicate the good anticoagulation and antibacterial properties of the (PrS/HGF-pDNA) multilayer film. The in vivo preliminary data of angiography and histological analysis suggest that the (PrS/HGF-pDNA) multilayer coated stent can reduce the in-stent restenosis. This work reveals that the (PrS/HGF-pDNA) multilayer film could be a promising candidate as coating for GES, which is of great potential in future clinic application. © 2014 Wiley Periodicals, Inc.

Haemodynamic imaging of thoracic stent-grafts by computational fluid dynamics (CFD): presentation of a patient-specific method combining magnetic resonance imaging and numerical simulations.

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Midulla, Marco; Moreno, Ramiro; Baali, Adil; Chau, Ming; Negre-Salvayre, Anne; Nicoud, Franck; Pruvo, Jean-Pierre; Haulon, Stephan; Rousseau, Hervé

2012-10-01

In the last decade, there was been increasing interest in finding imaging techniques able to provide a functional vascular imaging of the thoracic aorta. The purpose of this paper is to present an imaging method combining magnetic resonance imaging (MRI) and computational fluid dynamics (CFD) to obtain a patient-specific haemodynamic analysis of patients treated by thoracic endovascular aortic repair (TEVAR). MRI was used to obtain boundary conditions. MR angiography (MRA) was followed by cardiac-gated cine sequences which covered the whole thoracic aorta. Phase contrast imaging provided the inlet and outlet profiles. A CFD mesh generator was used to model the arterial morphology, and wall movements were imposed according to the cine imaging. CFD runs were processed using the finite volume (FV) method assuming blood as a homogeneous Newtonian fluid. Twenty patients (14 men; mean age 62.2 years) with different aortic lesions were evaluated. Four-dimensional mapping of velocity and wall shear stress were obtained, depicting different patterns of flow (laminar, turbulent, stenosis-like) and local alterations of parietal stress in-stent and along the native aorta. A computational method using a combined approach with MRI appears feasible and seems promising to provide detailed functional analysis of thoracic aorta after stent-graft implantation. • Functional vascular imaging of the thoracic aorta offers new diagnostic opportunities • CFD can model vascular haemodynamics for clinical aortic problems • Combining CFD with MRI offers patient specific method of aortic analysis • Haemodynamic analysis of stent-grafts could improve clinical management and follow-up.

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

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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.

Two Blades-Up Runs Using the JetStream Navitus Atherectomy Device Achieve Optimal Tissue Debulking of Nonocclusive In-Stent Restenosis: Observations From a Porcine Stent/Balloon Injury Model.

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Shammas, Nicolas W; Aasen, Nicole; Bailey, Lynn; Budrewicz, Jay; Farago, Trent; Jarvis, Gary

2015-08-01

To determine the number of runs with blades up (BU) using the JetStream Navitus to achieving optimal debulking in a porcine model of femoropopliteal artery in-stent restenosis (ISR). In this porcine model, 8 limbs were implanted with overlapping nitinol self-expanding stents. ISR was treated initially with 2 blades-down (BD) runs followed by 4 BU runs (BU1 to BU4). Quantitative vascular angiography (QVA) was performed at baseline, after 2 BD runs, and after each BU run. Plaque surface area and percent stenosis within the treated stented segment were measured. Intravascular ultrasound (IVUS) was used to measure minimum lumen area (MLA) and determine IVUS-derived plaque surface area. QVA showed that plaque surface area was significantly reduced between baseline (83.9%±14.8%) and 2 BD (67.7%±17.0%, p=0.005) and BU1 (55.4%±9.0%, p=0.005) runs, and between BU1 and BU2 runs (50.7%±9.7%, patherectomy. JetStream Navitus achieved optimal tissue debulking after 2 BD and 2 BU runs with no further statistical gain in debulking after the BU2 run. Operators treating ISR with JetStream Navitus may be advised to limit their debulking to 2 BD and 2 BU runs to achieve optimal debulking. © The Author(s) 2015.

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?

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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

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

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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

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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

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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.).

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

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