scholarly journals Stricture recanalisation of the distal urether with various endoprothesis

2010 ◽  
Vol 57 (2) ◽  
pp. 61-64 ◽  
Author(s):  
A. Mladenovic ◽  
K. Davidovic ◽  
B. Markovic ◽  
P. Anojcic ◽  
M. Stojadinovic ◽  
...  
Keyword(s):  
Percutaneous Nephrostomy ◽  
Covered Stent ◽  
Metallic Stents ◽  
Metal Stents ◽  
Covered Stents ◽  
Important Place ◽  
Distal Ureter ◽  
Number Of Patients ◽  
Study Results ◽  
New Generation

Introduction: Application of the metallic stents in the interventional uroradioligy is the result of continuous development of the new generation methods percutaneous nephrostomy (PCN), ballon catheter dilatation (BCD), methal and covered stent application. Application of metal stents in the renal canal system was attempted in order to eliminate BCD and PCN - related limitations as well as poor therapeutic results of these methods in a number of etiopathogenic groups of urinary stasis. Years - long application of interventional uroradiology methods, until the development of metallic stengts had shown the following therapeutics facts: PCN is incapable to resolve the cause of urinary obstruction. Permanent good therapeutic BCD results mostly depend on pathohistological aspect of the stricture, metallic stents are most frequently the last choice in therapeutics approch to urinary tract obstructions and their application is directly dependent on previous therapeutics results accomplished by PCN and BCD. In therapeutical sequences new generation of covered stents have important place as method of selection in patients of irreversible uroopstruction of distal ureter. Objective: The main goal of this study was to analyze therapeutics results, advanteges and shortages of insercion plastics and opened metallic endoprothesis, and to analyze results of covered methal applications on the contrary of using older interventional uroradiology methods. Method: Sixthytwo patients with distal urether strictures threated in the Deparment of interventional uroradiology Institute of Radiology Clinical centre of Serbia in Belgrade, participated in the study. Results were analyzed with Person's 2- test, Fisher test and Student T-test. Results: In our study we had highly significant differences in comparison with number of patients and type of stents during the time after recanalization was reached. Also it was highly significant differences according the type of used interventional uroradiology method that treated proliferation and the success of recanalization. Conclusion: Application of covered temporary uretheral stents have number advantages against using generation older permanent methal endoprothesis.

Mechanical Evaluation of Polyvinyl Alcohol Cryogels for Covered Stents

2010 ◽  
Vol 4 (3) ◽  
Author(s):  
Jason D. Weaver ◽  
David N. Ku
Keyword(s):  
Polyvinyl Alcohol ◽  
Membrane Damage ◽  
Balloon Catheter ◽  
Bare Metal Stents ◽  
Covered Stent ◽  
Cellular Migration ◽  
Metal Stents ◽  
Membrane Thickness ◽  
Covered Stents ◽  
Increased Risk

Covered stents could reduce restenosis rates by preventing cellular migration with a physical barrier and may have reduced thrombotic complications if an appropriate material is selected. Previous Dacron™ or poly(tetrafluoroethylene) (PTFE) covered stents have had mixed clinical results in part because they are too thick and too thrombogenic at small diameters. Ideally, the covering should be as thin as a stent strut, mechanically able to expand as much as a stent, and durable enough to withstand deployment. As an alternative to PTFE, thin polyvinyl alcohol (PVA) cryogel membranes were tested for their ability to stretch with uniaxial tension tests and for puncture strength with a modified ASTM method. Additionally, PVA cryogel covered stents were made by coating expanded bare metal stents. These covered stents were then hand-crimped onto a balloon catheter and expanded. PVA cryogel membranes were made as thin as 100 μm—thinner than some stent struts—and stretched to approximately 3.0 times their original diameter (similar to a stent during deployment). PVA cryogel membranes resisted puncture well with an average push-through displacement of 4.77 mm—allowing for safe deployment in vessels of up to 9 mm in diameter. Push-through displacement did not depend on membrane thickness in the range tested—a trait that could reduce stent profile without increased risk of puncture. All the PVA cryogel covered stents tolerated the crimping and expansion process well and there was little to no visible membrane damage. In conclusion, based on the results of these mechanical tests, PVA cryogels are mechanically suitable for covered stent membranes. This work represents a first step toward the creation of a new class of covered stent, which could prevent complications from both restenosis and thrombosis.

Nanofiber Covered Stent (NCS) for Vascular Diseases

2008 ◽  
Vol 2 (2) ◽  
Author(s):  
Yixiang Dong ◽  
Teo Wee Eong ◽  
Susan Liao ◽  
Casey Chan ◽  
S. Ramakrishna
Keyword(s):  
Cell Viability ◽  
Drug Loading ◽  
Vascular Diseases ◽  
Coronary Bypass ◽  
Covered Stent ◽  
Covered Stents ◽  
Sem Images ◽  
Brain Aneurysm ◽  
Electrospinning Technique ◽  
Study Results

Introduction: A covered stent is one whose length and circumference is enclosed with a membrane or fabric like material. Current covered stents have been used in the treatment of failed saphenous vein grafts in coronary bypass and coronary artery perforations. Covered stents have also been proposed in treating brain aneurysm. However, none of these applications showed satisfactory results. The deficiencies of the covered stents are 1) Large wall thickness 2) Rigidity 3) Non-biodegradable polymer with poor endothelialization. Materials and methods: Aligned poly(L-lactide-co-epsilon-caprolactone) [P(LLA-CL)] nanofiber was lon-gitudinally deposited on to a bare metal stent (BMS) by a patent pending electrospinning technique. The NCS were deployed following the instruction to evaluate the expandability. Biocompatibility of the nanofiber was characterized by cell culture, degradation and drug eluting study. Results: The cell viability of Porcine smooth muscle cells (PSMC) on the nanofiber was initially low but caught up after 2weeks. SEM images showed 100% of cell confluence on the nanofiber after 2months. Significant amount of ECM protein was detected on P(LLA-CL) nanofiber (0.07mg∕cm2 at day 70). Complete degradation of P(LLA-CL) is expected within 6months. Paclitaxel released from drug loaded nanofiber was shown to inhibit PSMC growth but kill Hela cells. NCS was successfully fabricated and deployed without tearing the nanofiber. Conclusions: NCS was successfully fabricated. P(LLA-CL) was chosen for the “cover” with proved superiorities on biocompatibility, cell viability, degradability and drug loading capacity. Future work will be animal study to prove that NCS can reduce in-stent restenosis and promote endothelialization.

Covered Stents for Endovascular Treatment of Aortoiliac Occlusive Disease: A Systematic Review and Meta-Analysis

2021 ◽  
pp. 153857442110103
Author(s):  
Austin Mallory ◽  
Stefanos Giannopoulos ◽  
Paul Lee ◽  
Damianos G. Kokkinidis ◽  
Ehrin J. Armstrong
Keyword(s):  
Meta Analysis ◽  
Bare Metal Stents ◽  
Covered Stent ◽  
Primary Patency ◽  
Metal Stents ◽  
Covered Stents ◽  
Stent Group ◽  
Aortoiliac Occlusive Disease ◽  
The Individual

Purpose: The treatment of aortoiliac occlusive disease (AIOD) has largely shifted to endovascular techniques, with primary stenting constituting the preferred treatment approach. The goal of the current study was to summarize available literature and to determine whether covered stents are superior to bare metal stents for the treatment of AIOD, in terms of both periprocedural and long-term outcomes. Methods: A meta-analysis of 47 studies was conducted with the use of random effects modeling. The incidence of adverse events during follow up among the individual included studies was synthesized. Results: Most of the lesions were located at the common iliac arteries and were chronic total occlusions. The procedure was technically successful in almost all cases in both groups, with a low rate of periprocedural complications observed in both groups. The reported primary patency rates for the non-covered and covered stent group during an average follow up of 24.3 months among the individual studies, were 84% and 92% respectively, while surgical or endovascular re-intervention was required in 10% of non-covered stent cases and in 6% of covered stent cases. Eight studies comparing covered vs non-covered stents in terms of patency demonstrated superiority of covered stents (OR: 2.47; 95% CI: 1.01-6.01; p = 0.047 Combining TASC C/D lesions together 12 studies reported 92% (95%CI:89%-95%) primary patency in the covered stent group, while 7 studies reported 75% (95%CI: 60%-88%) primary patency for cases treated with non-covered stents. Conclusion: This study demonstrated that covered stents are safe and effective when utilized for the treatment of AIOD. Covered stents were associated with a statistically significant higher odds of primary patency in both the overall cohort and in more complex TASC C/D lesions. However, additional high-quality comparative analyses between covered vs bare metal stents and between several types of covered stents are needed to determine the most optimal treatment modality for AIOD.

scholarly journals Antegrade biliary stenting for obstructive jaundice

2019 ◽  
Vol 24 (2) ◽  
pp. 25-35
Author(s):  
A. V. Andreev ◽  
V. M. Durleshter ◽  
A. I. Leveshko ◽  
S. A. Gabriel ◽  
E. V. Tokarenko
Keyword(s):  
Obstructive Jaundice ◽  
Bare Metal Stents ◽  
Metallic Stents ◽  
Metal Stents ◽  
Covered Stents ◽  
Bare Metal ◽  
Biliary Stenting ◽  
Malignant Obstructive Jaundice ◽  
Invasive Approach ◽  
Expandable Metallic Stents

Objective. To determine the role bile duct stenting with self-expandable metallic stents in the treatment of malignant obstructive jaundice. Material and methods. Eight-year experience of palliative antegrade stenting with self-expandable metallic stents was analyzed. There were 218 patients with malignant obstructive jaundice. Distal and proximal obstruction was diagnosed in 118 (54%) and 100 (46%) patients, respectively. We have used self-expandable metallic covered, partially covered and bare-metal stents with diameter of 10, 8 and 6 mm and length of 40, 60 and 80 mm. Results. Technical success in antegrade two-stage installation of self-expandable stents have been achieved in 208 (99%) patients. There were 230 deployed self-expandable metallic stents. Seven (3%) patients underwent simultaneous stenting of right and left hepatic ducts and confluence area with bare-metal stents. Stenting of right or left hepatic ducts and confluence area with partially covered stents was carried out in 34 (16%) patients. Other 59 (27%) patients with proximal biliary obstruction and no separation of lobar bile ducts underwent stenting with 27 partially covered and 31 covered stents. Distal obstruction was managed by using of covered stents as a rule (63%). Complications after antegrade biliary stenting occurred in 29 (13%) patients. Conclusion. Antegrade biliary stenting with metallic self-expandable stents is effective and minimally invasive approach. Moreover, it is comparable with conventional palliative interventions aimed at bile outflow recovery.

scholarly journals A computational framework examining the mechanical behaviour of bare and polymer-covered self-expanding laser-cut stents

2021 ◽  
Author(s):  
Ciara G. McKenna ◽  
Ted J Vaughan
Keyword(s):  
Mechanical Performance ◽  
Bare Metal Stents ◽  
Covered Stent ◽  
Polymer Materials ◽  
Axial Stiffness ◽  
Metal Stents ◽  
Covered Stents ◽  
Computational Framework ◽  
Bending Response

Polymer covered stents have demonstrated promising clinical outcomes with improved patency rates compared to traditional bare-metal stents, however little is known on the mechanical implication of stent covering. In the present work, a combined experimental-computational investigation was carried out to determine the role of a polymeric cover on the biomechanical performance of self-expanding laser-cut stents. Experimental bench top tests were conducted on bare and covered versions of a commercial stent to evaluate the radial, axial and bending response. In parallel, a computational framework with a novel covering strategy was developed that accurately predicts stent mechanical performance, and provides further insight into covered stent mechanics by considering different stent geometries and polymer materials. Results show that stent covering causes increased initial axial stiffness and substantial radial stiffening at small crimp diameters as the cover folds and self-contacts. It was also shown that use of a stiffer polymeric covering material caused significant alterations to the radial and axial response, highlighting the importance of considering the mechanical properties of the combined cover and stent.

Covered and Uncovered Self-Expandable Metallic Stents in the Treatment of Malignant Biliary Obstruction

2020 ◽  
Vol 22 (7) ◽  
Author(s):  
Lian-Biao Li ◽  
Wen-Yan Qin ◽  
Wen-Ping Peng ◽  
Jin-Zhen Li ◽  
Ming-Ming Zhang ◽  
...  
Keyword(s):  
Biliary Obstruction ◽  
Meta Analysis ◽  
Malignant Biliary Obstruction ◽  
Metallic Stents ◽  
Metal Stents ◽  
Stent Patency ◽  
Advantages And Disadvantages ◽  
Study Results ◽  
Significant Difference ◽  
Expandable Metallic Stents

Context: Self-expandable metal stents (SEMSs) are commonly used in the treatment of malignant biliary obstruction. We performed a meta-analysis to compare the efficacy of covered self-expandable metallic stents (CSEMSs) and uncovered self-expandable metallic stents (UCSEMSs) for patients with malignant distal biliary obstruction. Methods: A comprehensive search was conducted using PubMed, Embase, Cochrane, and CNKI databases from 2010 to 2019. All randomized controlled trials, which compared the use of the CSEMSs and UCSEMSs for the treatment of malignant distal biliary obstruction were included in this study. Results: This meta-analysis included 1,539 patients enrolled in 13 trials. There was no difference between the two groups in terms of patients’ survival (hazard ratio (HR) 0.96, 95% confidence interval (CI): 0.87 - 1.07; I2 = 32.6%), stent patency (HR 0.92, 95% CI: 0.69 - 1.22; I2 = 56.3%), and the overall complication rate (relative risks (RR) 1.35, 95% CI: 0.82 - 2.23; I2 = 0%). In particular, the CSEMSs group presented a lower rate of tumor ingrowth (RR 0.30, 95% CI: 0.15 - 0.57; I2 = 58.5%) than the UCSEMSs group. However, the CSEMSs group exhibited a higher rate of tumor overgrowth (RR 1.63, 95% CI: 1.00 - 2.66; I2 = 0%), sludge formation (RR 2.28, 95% CI: 1.36 - 3.82; I2 = 0%), and migration (RR 5.14, 95% CI: 1.90 - 13.88; I2 = 0%). Conclusions: Our meta-analysis indicated that there was no significant difference between the two stents, and each one had its advantages and disadvantages.

Pre-clinical and Clinical Study Results for the Coracto™ Rapamycin-eluting Stent – A New-generation Drug-eluting Stent

2010 ◽  
Vol 5 (1) ◽  
pp. 39 ◽  
Author(s):  
Nicolaus Reifart ◽  
Mariann Gyöngyösi ◽  
Hauptmann Karl-Eugen ◽  
Alexander Rabe ◽  
Darius Enayat ◽  
...  
Keyword(s):  
Clinical Study ◽  
Stent Thrombosis ◽  
Rabbit Model ◽  
Bare Metal Stents ◽  
Metal Stents ◽  
Late Stent Thrombosis ◽  
Safety And Efficacy ◽  
Study Results ◽  
Drug Eluting ◽  
New Generation

First- and second-generation drug-eluting stents (DES) have successfully decreased the rate of restenosis compared with bare-metal stents (BMS); however, the incidence of late stent thrombosis, which mostly occurs after the implantation of DES, and chronic restenosis are still important medical problems. A new generation of DES, the Coracto™ rapamycin-eluting stent (RES), has the potential to reduce late stent thrombosis and the risk of chronic restenosis due to the totally biodegradable polymer providing a controlled drug release. In brief, the results of the two pre-clinical studies proved the safety and efficacy of the Coracto RES. In addition, in a clinical study comparing the Coracto RES and the Constant BMS, patients receiving the Coracto RES with chronic total occlusion (CTO) had a 71% decrease in the relative risk of restenosis after six months and an 82% reduction in target vessel revascularisation (TVR) after 24 months. The late stent thrombosis of the Coracto RES was 0% at 24-month follow-up. This article provides an overview of the data obtained from pre-clinical animal experiments using a porcine and rabbit model of stenting and a recently conducted clinical study demonstrating the safety and efficacy of the Coracto RES.

Treatment of Malignant Esophageal Fistulas: Fluoroscopic Placement of Esophageal SEMS, Endoscopically-assisted through Surgical Gastrostomy. A Case Report

2016 ◽  
Vol 25 (2) ◽  
pp. 249-252 ◽  
Author(s):  
Gabriel Constantinescu ◽  
Vasile Şandru ◽  
Mădălina Ilie ◽  
Cristian Nedelcu ◽  
Radu Tincu ◽  
...  
Keyword(s):  
Esophageal Carcinoma ◽  
Guide Wire ◽  
Subsequent Development ◽  
Covered Stent ◽  
Metallic Stents ◽  
Fistula Formation ◽  
Life Threatening ◽  
Endoscopic Placement ◽  
Surgical Gastrostomy ◽  
Methods Of Treatment

Progressive esophageal carcinoma can infiltrate the surrounding tissues with subsequent development of a fistula, most commonly between the esophagus and the respiratory tract. The endoscopic placement of covered self-expanding metallic stents (SEMS) is the treatment of choice for malignant esophageal fistulas and should be performed immediately, as a fistula formation represents a potential life-threatening complication. We report the case of a 64-year-old male diagnosed with esophageal carcinoma, who had a 20Fr surgical gastrostomy tube inserted before chemo- and radiotherapy and was referred to our department for complete dysphagia, cough after swallowing and fever. The attempt to insert a SEMS using the classic endoscopic procedure failed. Then, a fully covered stent was inserted, as the 0.035” guide wire was passed through stenosis retrogradely by using an Olympus Exera II GIF-N180 (4.9 mm in diameter endoscope) via surgical gastrostomy, with a good outcome for the patient. The retrograde approach via gastrostomy under endoscopic/fluoroscopic guidance with the placement of a fully covered SEMS proved to be the technique of choice, in a patient with malignant esophageal fistula in whom other methods of treatment were not feasible. Abbreviations: ERCP: endoscopic retrograde cholangio-pancreatography; GI: gastrointestinal; SEMS: self-expandable metallic stents.

Transbrachial and transfemoral approaches combined with visceral protection for the treatment of juxtarenal aortoiliac occlusive disease: Technical issues and clinical outcomes

Vascular ◽  
2021 ◽  
pp. 170853812110232
Author(s):  
Peixian Gao ◽  
Changliang Li ◽  
Xuejun Wu ◽  
Gang Li ◽  
Dianning Dong ◽  
...  
Keyword(s):  
Endovascular Treatment ◽  
Bare Metal Stents ◽  
Covered Stent ◽  
Occlusive Disease ◽  
Metal Stents ◽  
Infrarenal Aorta ◽  
Bare Metal ◽  
Stent Grafts ◽  
Aortoiliac Occlusive Disease

Purpose To evaluate the safety and efficacy of transbrachial and transfemoral approaches combined with visceral protection for the endovascular treatment of juxtarenal aortoiliac occlusive disease (AIOD) over an average 19-month follow-up period. Methods In this retrospective analysis, all patients with juxtarenal AIOD at a single institution were reviewed from June 2015 to January 2020. Patient characteristics, angiographic results, and follow-up outcomes were retrospectively recorded. The indications for treatment were critical limb threatening ischemia in 12 patients and bilateral claudication in five patients. Percutaneous access via the left brachial artery was first obtained to recanalize the infrarenal occluded lesions. After that, femoral accesses were achieved. A 4-Fr catheter, a 4 mm balloon, or a 6-Fr 90-cm-long sheath was used to complete visceral artery protection. Results A total of 17 juxtarenal AIOD patients (14 males; mean age, 63.4 ± 8.1 years) underwent endovascular treatment. The technical success rate was 100%. Complete reconstruction was achieved in 15 (88.2%) patients. The infrarenal aorta was reconstructed with kissing covered stent grafts ( n = 7), kissing bare-metal stents ( n = 2), covered stent grafts ( n = 2), bare-metal stents ( n = 1), or the off-label use of iliac limb stent grafts ( n = 5). Renal embolization was found in 3 (17.6%) patients during intraoperative angiography. There was 1 (5.9%) case of distal runoff embolization after CDT and 1 (5.9%) case of left iliac artery rupture. One (5.9%) death occurred due to acute myocardial infarction 20 days after the operation. The average follow-up period was 19.3 ± 16.7 months (range, 1–54 months) in the remaining 16 cases. The renal artery patency rate was 100%. The estimated cumulative primary patency rates were 92.3% at 12 months and 59.3% at 36 months according to the Kaplan–Meier method. Conclusions Transbrachial and transfemoral approaches combined with visceral protection offer a safe and effective alternative to open revascularization for the endovascular treatment of juxtarenal AIOD.

scholarly journals Epidemiology of Secondary Warm Autoimmune Haemolytic Anaemia—A Systematic Review and Meta-Analysis

2021 ◽  
Vol 10 (6) ◽  
pp. 1244
Author(s):  
Stinne Tranekær ◽  
Dennis Lund Hansen ◽  
Henrik Frederiksen
Keyword(s):  
Haemolytic Anaemia ◽  
Lupus Erythematosus ◽  
Meta Analysis ◽  
Underlying Disease ◽  
Age At Diagnosis ◽  
Autoimmune Haemolytic Anaemia ◽  
Sex Distribution ◽  
Number Of Patients ◽  
Study Results ◽  
Full Text Review

Background: Warm autoimmune haemolytic anaemia (wAIHA) is a haemolytic disorder, most commonly seen among adults and is classified as either primary or secondary to an underlying disease. We describe the age and sex distribution and the proportion of secondary wAIHA. Method: We retrieved 2635 published articles, screened abstracts and titles, and identified 27 articles eligible for full-text review. From these studies, we extracted data regarding number of patients, sex distribution, age at diagnosis, number of patients with secondary wAIHA, and whether the patients were diagnosed through local or referral centres. All data were weighted according to the number of included patients in each study. Results: 27 studies including a total of 4311 patients with wAIHA, of which 66% were females, were included. The median age at diagnosis was 68.7 years, however, wAIHA affected all ages. The mean proportion of secondary wAIHA was 49%, most frequently secondary to systemic lupus erythematosus. The proportions of secondary wAIHA reported from primary vs. referral centres were 35% vs. 59%, respectively. Conclusion: This review consolidates previously reported gender distribution. The higher proportion of secondary wAIHA in referral centres suggests that the most severely affected patients are disproportionally more frequent in such facilities.

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