Fatigue Resistance of the Advanta V12/iCast and Viabahn Balloon-Expandable Stent-Graft as Bridging Stents in Experimental Fenestrated Endografting

2021 ◽  
pp. 152660282199672
Author(s):  
Giovanni Torsello ◽  
Marcus Müller ◽  
Sarah Litterscheid ◽  
Bärbel Berekoven ◽  
Martin Austermann ◽  
...  
Keyword(s):  
Stent Graft ◽  
Fatigue Resistance ◽  
Transluminal Angioplasty ◽  
Fatigue Tests ◽  
Stent Fracture ◽  
Stent Grafts ◽  
Radiographic Images ◽  
Significant Difference ◽  
Prolonged Stress ◽  
Layer Defect

Purpose: Bridging stents undergo millions of cycles during respiratory movements of the kidneys throughout the patient’s life. Thus, understanding the response of fabric and endoskeleton of the stent to cyclic loading over the time is crucial. In this study, we compare the fatigue resistance of the Viabahn Balloon-Expandable stent-graft (VBX) with the widely used Advanta V12/iCast under prolonged stress induction. Materials and Methods: A polyester test sheet with 10 fenestrations was used simulating a fenestrated endograft. Five 6×59 mm VBX stent-grafts and five 6×58 mm Advanta stent-grafts were implanted into 6×6 mm fenestrations. The stents were flared with a 10×20 mm PTA (percutaneous transluminal angioplasty) catheter and connected with a fatigue stress machine. All stent-grafts were evaluated by microscopy and radiography at baseline and after regular intervals until 50,000,000 cycles were applied, simulating a life span of approximately 75 months. Freedom from fracture (FF), freedom from initial polytertafluoroethylene (PTFE) changes (FIC), and from PTFE breakpoint (FBP, all-layer defect) were calculated. Results: Digital radiographic images did not show any stent fracture in both groups after 50,000,000 cycles. The VBX stent-graft was free from any all-layer defects at the conclusion of 50,000,00 cycles resulting in a significant higher FBP compared with Advanta V12 (50,000,000 vs 33,400,000; p<0.01). All-layer defects were observed only in the Advanta group. Two of 5 Advanta stents showed early penetration of the nitinol ring causing a defect of PTFE. Regarding FIC, there was no significant difference between the stents (3,400,000 in VBX vs 3,200,000 in Advanta). Conclusions: In fatigue tests simulating respiration movements, VBX and Advanta V12 performed equally well in terms of fracture resistance and freedom from initial PTFE changes. VBX maintained freedom from PTFE breakpoint throughout the full 50,000,000 cycles. All-layers defects were detected only in Advanta and were mainly caused by penetration of the nitinol ring through the PTFE.

scholarly journals Stent grafts improved patency of ruptured hemodialysis vascular accesses

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Min-Tsun Liao ◽  
Chien-Ming Luo ◽  
Ming-Chien Hsieh ◽  
Mu-Yang Hsieh ◽  
Chih-Ching Lin ◽  
...  
Keyword(s):  
Stent Graft ◽  
Target Lesion ◽  
Transluminal Angioplasty ◽  
Primary Patency ◽  
Dialysis Access ◽  
Stent Grafts ◽  
Index Procedure ◽  
Balloon Tamponade ◽  
Significant Difference ◽  
Percutaneous Transluminal

AbstractThis study aimed to compare stent graft with balloon tamponade for ruptured dialysis access during percutaneous transluminal angioplasty. Patients over an 8-year period (2010–2018) were identified from a database of 11,609 procedures. The primary endpoint was target lesion primary patency at 12 months. A total of 143 patients who had rupture dialysis access were enrolled, of whom 52 were salvaged by stent grafts and 91 were salvaged by balloon tamponade. The 6-month target lesion primary patency was greater in the stent graft group than in the balloon tamponade group (66.7% vs. 29.5%, P < 0.001). The benefit of stent grafts was sustained for 12 months (52.5% vs. 9.0%, P < 0.001). The stent grafts increased the median time from the index procedure to the next intervention in the ruptured area by 171 days (260 vs. 89 days) at 12 months. There was no significant difference in the access circuit patency rates at 6 months (25.5% vs. 19.8%, P = 0.203) and 12 months (12.0% vs. 5.8%, P = 0.052). The patency results of the stent grafts remained after the multivariable adjustment analysis. Compared to balloon tamponade alone, stent grafts provided superior target lesion primary patency at 6 and 12 months. The access circuit patency rates were similar.

Abstract 249: Stationary Signal and Flow Velocity Assessment by MRI of a New Nitinol Nanocomposite Polymer Stent-Graft

2012 ◽  
Vol 32 (suppl_1) ◽  
Author(s):  
Mital Desai ◽  
Rachel E Clough ◽  
Nicholas R Gaddum ◽  
Kawal Rhode ◽  
Xiang Zhou ◽  
...  
Keyword(s):  
Steady Flow ◽  
Stent Graft ◽  
Signal Attenuation ◽  
Stent Grafts ◽  
Mean Velocity ◽  
Nanocomposite Polymer ◽  
Significant Difference ◽  
Flow Phantom ◽  
Flow Flux ◽  
Commercial Device

Objective: To assess MRI compatibility and suitability of a new sutureless stent-graft made from Nitinol bonded to nanocomposite polymer (NP). Methods: 1. Using MRI and Magnevist contrast, isotropic 3D T1-weighted FFE images of NP stent-graft were acquired to observe artefacts and stationary signal attenuation. Average signal magnitude was calculated. Medtronic ValiantTM was used as control. 2. In second stage, steady flow phantom was setup for flow-encoded MRI signal assessment of both stent-grafts. Baseline values were obtained by velocity measurements without stent-graft using identical settings. 2D through-plane phase contrast images were acquired and average velocity and amount of flow (flux) were calculated. Results: On static assessment of NP and ValiantTM stent-grafts no significant image artefacts were seen. The signal inside and outside the ValiantTM stent-graft was 644.2(SD 36.2) and 659.6(SD 85.8) respectively. The signal attenuation for this device was 2.39%. The signal inside and outside the NP stent graft was 1561.7(SD 31.2) and 1595.5(SD 40.8) respectively with comparable signal attenuation of 2.16%. In MRI velocity attenuation study, steady flow phantom was set at mean volume of 105.3 ml and mean velocity of 79.5 cm/sec. Flux measured in ValiantTM stent-graft was 102±2.27 ml/sec with no significant difference to baseline (104±1.98 ml/sec; P=0.892). Similarly flux for NP stent-graft at mean stroke volume 104.4 ml and mean velocity of 92.3 cm/sec showed no difference to baseline (99.8±2.4 vs. 104±0.96 ml/sec; P=0.176). There was no significant difference in flux between Medtronic and NP stent-grafts (102±2.27 vs. 99.8±2.4 ml/sec; P=0.328). Conclusion: NP stent-graft does not display any material-induced artefacts on MRI. On flow assessment, signal attenuation is comparable with the commercial device. These properties are important in developing this stent-graft, compliant, durable, visco-elastic, biocompatible and anti-thrombogenic, for future clinical use.

Early stent fracture and collapse of a Zenith TX2 thoracic stent graft used for traumatic aortic rupture

Vascular ◽  
2011 ◽  
Vol 19 (5) ◽  
pp. 287-290 ◽  
Author(s):  
Mårten Falkenberg ◽  
Jonas Cronqvist ◽  
Martin Malina
Keyword(s):  
Stent Graft ◽  
Aortic Rupture ◽  
Stent Fracture ◽  
X Rays ◽  
Structural Failure ◽  
Stent Grafts ◽  
Lethal Outcome ◽  
Retrospective Assessment ◽  
Aortic Transection

Structural failure and collapse of thoracic stent grafts may cause fatal complications that are easily overlooked on follow-up imaging. A young man with multiple injuries from a motorcycle crash was treated with endografting for an aortic transection. The clinical course was initially satisfactory but deteriorated one week after the injury and the patient died two weeks later. Autopsy and retrospective assessment of chest X-rays revealed early fractures and collapse of the stent graft that had been overlooked and may have contributed to the lethal outcome. The design of thoracic stent grafts needs to be improved for treatment of traumatic aortic transection. Careful follow-up of these patients is warranted.

scholarly journals Multicenter Experience With Large Diameter Balloon-Expandable Stent-Grafts for the Treatment of Infrarenal Penetrating Aortic Ulcers

2021 ◽  
pp. 152660282110282
Author(s):  
Jan Stana ◽  
Carlota Fernandez Prendes ◽  
Lukasz Kruszyna ◽  
Ioannis Thomas Passaloglou ◽  
Maria Antonella Ruffino ◽  
...  
Keyword(s):  
Stent Graft ◽  
Large Diameter ◽  
Small Diameter ◽  
Operation Time ◽  
Stent Fracture ◽  
Stent Grafts ◽  
Femoral Access ◽  
Mortality And Morbidity ◽  
Perioperative Morbidity ◽  
Aortic Stent Graft

Purpose To describe the use of large-diameter balloon-expandable stent-grafts (BeGraft aortic stent-graft, Bentley InnoMed GmbH, Hechingen, Germany) in the treatment of infrarenal penetrating aortic ulcer (iPAU). Materials and Methods Retrospective analysis of patients undergoing endovascular treatment with the BeGraft aortic stent-graft in 8 European centers from January 2017 to October 2020. Demographics, perioperative data, and midterm outcomes were collected. Endpoints of the study were technical feasibility, early mortality, and morbidity. Results A total of 40 patients were included. The mean age was 73.9±7.05 years and 63.2% were male. Indications for treatment included size and morphology (65%), presence of symptoms (29.5%), and contained ruptures (5.5%). Urgent treatment was performed in 5% of cases. Technical success was 97.5%. Median operation time was 58 minutes (19–170 minutes), with 27.5% of patients having additional procedures during the main intervention (1 additional repair with a C-TAG (W.L. Gore & Associates, Inc, Flagstaff, AZ, USA) thoracic endoprosthesis, 5 covered endovascular reconstruction of aortic bifurcation procedures, 3 extensions with proximal cuffs, and 2 percutaneous angioplasties of the common iliac arteries). Percutaneous femoral access was used in 72.5%, while groin cut-down was performed in 27.5%. Repair was successful with only 1 stent in 45% of cases, while 37.5% required 2 stents and nearly 17.5% required 3/4 stent-grafts. The 30-day mortality was 0%, with a 2.5% reintervention rate (1 patient required evacuation of an intra-abdominal hematoma). Median follow-up was 13.9 months (2–39 months), during which no vascular-related reinterventions or deaths were reported. In 4 patients, a type II endoleak was observed. No cases of graft migration, thrombosis, or stent-fracture were observed. Conclusions The treatment of iPAU with the BeGraft aortic stent-graft in a selective patient group is feasible with low rate of perioperative morbidity and mortality. Balloon-expandable stent-grafts offer the option to repair iPAUs with a shorter coverage of the aorta using low-profile sheath, that enables treatment in the presence of calcified access vessels and small diameter aortic bifurcations.

The Effects on the Strength of UBM Extracellular Matrix Under Stent Loading: An Experimental and Numerical Study

2009 ◽  
Author(s):  
Anthony Callanan ◽  
Michael Walsh ◽  
Tim McGloughlin
Keyword(s):  
Stent Graft ◽  
Numerical Study ◽  
Covered Stent ◽  
Western World ◽  
Stent Fracture ◽  
Stent Grafts ◽  
Tissue Engineering Scaffolds ◽  
Autologous Vein ◽  
Drug Elution ◽  
Improved Design

Arterial diseases are a common cause of death in the western world. The last two decades has seen vast improvements in scanning, screening, prognosis and symptom recognition, resulting in a greater number of treatments. A common treatment procedure used is bypass grafting which currently utilize synthetic graft materials, internal thoracic artery, and autologous vein. These treatments are invasive surgical procedures and can have low patency. An alternative treatment for these conditions is endovascular surgery. However these devices have problems such as restenois, migration and stent fracture. Improved design and drug elution have been utilized to enhance the performance, with limited success. The application of Tissue engineering scaffolds to enhance device performance has had limited studies. A Number of studies have looked at Small Intestine Submucosa in stenting applications [1, 2]. One study implanted an ECM (SIS) stent-graft into 8 sheep. The study concluded that the ECM stent graft successfully treated simple and ruptured AAA’s. Another study investigated a stent graft arrangement in the femoral arteries of sheep. The study found that SIS coated stent preformed better than that of PTFE covered stent grafts.

In Vitro Evaluation of the Gore Viabahn Balloon-Expandable Stent-Graft for Fenestrated Endovascular Aortic Repair

2019 ◽  
Vol 26 (3) ◽  
pp. 361-368 ◽  
Author(s):  
Giovanni Federico Torsello ◽  
Monika Herten ◽  
Markus Müller ◽  
André- Frank ◽  
Giovanni B. Torsello ◽  
...  
Keyword(s):  
Shear Stress ◽  
Stent Graft ◽  
Water Permeability ◽  
Intraluminal Pressure ◽  
Stent Fracture ◽  
Main Body ◽  
Stress Tests ◽  
Stent Grafts ◽  
Average Force

Purpose: To evaluate the safety and integrity of a new stent-graft as a potential bridging device in fenestrated stent-grafts using an in vitro fenestrated model. Materials and Methods: Polyester test sheets with ten 6-mm- or 8-mm-diameter fenestrations were used to simulate a fenestrated main body endoprosthesis. In total, 50 Viabahn balloon-expandable (VBX) stent-grafts of varying lengths (29 and 39 mm) and diameters (6, 7, and 8 mm) were implanted in the fitting fenestrations. After release, the 6- and 7-mm-diameter stent-grafts were flared with a 10×20-mm angioplasty balloon; a 12×20-mm balloon was used in the 8-mm-diameter devices. Safety of the devices was defined as absence of fractures detected on radiography or computed tomography (CT), as well as material failure detected by microscopy and water permeability testing. The forces (in Newtons, N) needed for perpendicular dislocation (pullout force) and axial dislocation (shear stress force) were also evaluated. Results: Forty VBX stent-grafts were subjected to digital radiographic imaging and multiplanar CT. None showed any stent fracture. Subsequent microscopy indicated no damage to the fabric or separation of the graft after flaring. Ten VBX stent-grafts underwent water permeability testing after flaring; no water passed through the graft wall during a 10-minute period under an intraluminal pressure at 120 mm Hg. Testing of 25 VBX stent-grafts revealed initial pullout forces between 11.3 and 31 N. Shear stress tests showed that the average force needed to dislocate the stent-grafts by 50% of their diameter ranged between 5.75 and 6.91 N (mean 6.1±0.5 N) for the 6-mm stents and between 3.31 and 5.4 N (mean 4.4±0.8) for the 8-mm stents. Conclusion: This preliminary study demonstrated the applicability of the VBX as a bridging stent-graft in a simulated fenestration model. A comparison with other stent-grafts and clinical assessment are required.

Endovascular stent-graft treatment for graft-vein anastomotic stenosis in haemodialysis patients with arteriovenous grafts

VASA ◽  
2015 ◽  
Vol 44 (6) ◽  
pp. 466-472 ◽  
Author(s):  
Chia-Hsun Lin ◽  
Yen-Yang Chen ◽  
Chai-Hock Chua ◽  
Ming-Jen Lu
Keyword(s):  
Risk Factors ◽  
Stent Graft ◽  
Target Lesion ◽  
Primary Patency ◽  
Anastomotic Stenosis ◽  
Secondary Patency ◽  
Endovascular Stent ◽  
Stent Grafts ◽  
Venous Anastomosis ◽  
Arteriovenous Grafts

Abstract. Background: In this study, we investigated the patency of endovascular stent grafts in haemodialysis patients with arteriovenous grafts, the modes of patency loss, and the risk factors for re-intervention. Patients and methods: Haemodialysis patients with graft-vein anastomotic stenosis of their arteriovenous grafts who were treated with endovascular stent-grafts between 2008 and 2013 were entered into this retrospective study. Primary and secondary patency, modes of patency loss, and risk factors for intervention were recorded. Results: Cumulative circuit primary patency rates decreased from 40.0 % at 6 months to 7.3 % at 24 months. Cumulative target lesion primary patency rates decreased from 72.1 % at 6 months to 22.0 % at 24 months. Cumulative secondary patency rates decreased from 81.3 % at 12 months to 31.6 % at 36 months. Patients with a history of cerebrovascular accident had a significantly higher risk of secondary patency loss, and graft puncture site stenosis jeopardised the results of stent-graft treatment. Conclusions: Our data can help to improve outcomes in haemodialysis patients treated with stent-grafts for venous anastomosis of an arteriovenous graft.

scholarly journals Effect of synchronous irrigation on cyclic fatigue of nickel-titanium instrument in the dynamic and static models

2021 ◽  
Vol 19 ◽  
pp. 228080002098740
Author(s):  
Haiyun Liu ◽  
Yanfeng Li ◽  
Guangquan Chai ◽  
Yuan Lv ◽  
Changjian Li ◽  
...  
Keyword(s):  
Fatigue Resistance ◽  
Flow Rate ◽  
Dynamic Control ◽  
Cyclic Fatigue ◽  
Nickel Titanium ◽  
Control Group ◽  
Time To Failure ◽  
Dynamic Tests ◽  
Significant Difference ◽  
Experimental Group

Objective: To evaluate the effect of synchronous water irrigation on the fatigue resistance of nickel-titanium instrument. Methods: A standardized cyclic fatigue test models were established, and five types of nickel-titanium instruments (PTU F1, WO, WOG, RE, and M3) were applied. Each instrument was randomly divided into two groups ( N = 12). There was synchronous water irrigation in the experimental group, and no water irrigation in the control group. Besides, ProTaper Universal F1 was randomly divided into 10 groups ( N = 20). In the static group, nickel-titanium instruments were divided into one control group (no irrigation, N = 20) and six experimental group (irrigation, N = 20) based on different flow rate, angle and position; while in the dynamic group, instruments were divided into one control group (no irrigation, N = 20) and two experimental group (irrigation, N = 20) based on different flow rate. The rotation time (Time to Failure, TtF) of instruments was recorded and analyzed. Results: According to the static experiments, the TtF of instruments in all experimental groups was significantly higher than that in the static control group. Besides, the dynamic tests of PTU F1 showed that the TtF in the experimental group was significantly higher than that in the dynamic control group. Compared with control group, the TtF in the experimental groups increased by at least about 30% and up to 160%. The static and dynamic tests of PTU F1 showed that the TtF of nickel-titanium instrument in all experimental groups was significantly higher than that in the control group. However, there was no significant difference between any two experimental groups. Conclusion: Regardless of dynamic or static model, TtF with irrigation was longer than that with non-irrigation, indicating that synchronous irrigation can increase the fatigue resistance of nickel-titanium instrument. However, different irrigation conditions may have the same effect on the fatigue resistance.

scholarly journals Mechanisms of Intravascular Linear Ablation Induced Restenosis in Rabbit Abdominal Aorta

2018 ◽  
Vol 2018 ◽  
pp. 1-11
Author(s):  
Qiang Chen ◽  
Manman Wang ◽  
Shuai Shao ◽  
Hongze Liu ◽  
Xiaodong Xia ◽  
...  
Keyword(s):  
Intimal Hyperplasia ◽  
Coronary Intervention ◽  
Transluminal Angioplasty ◽  
Artery Dissection ◽  
Control Group ◽  
High Cholesterol Diet ◽  
Control Groups ◽  
Vsmc Proliferation ◽  
Significant Difference ◽  
And Control

Objectives. Percutaneous coronary intervention (PCI) is the mainstay treatment for coronary artery disease but complications such as in-stent restenosis and thrombosis remain problematic. Radiofrequency balloon angioplasty (RBA) can improve lumen dimension, fusing intimal tears, and artery dissection but is associated with higher restenosis rate. Methods. After establishing an atherosclerosis model based on endothelial abrasion and high cholesterol diet, forty-five rabbits were randomly divided into three groups: RBA (n=20), percutaneous transluminal angioplasty (PTA) (n=20), and control groups (n=5). The RBA and PTA groups were subdivided according to harvested time posttreatment, respectively (1 hour, 7 days, 14 days, and 28 days). Aorta segments were then isolated for hematoxylin and eosin staining, Masson trichrome staining, immunohistochemistry, and Western blot for TLR-4, NF-κB, MCP-1, and VCAM-1expression. Results. At 28 days, intimal area was significantly lower in the RBA group compared to the PTA and control groups, whilst luminal and medial area were comparable in the RBA and PTA group but higher and lower than the control group, respectively. Expression of TLR-4, NF-κB, MCP-1, and VCAM-1 showed no significant difference between RBA and PTA groups. Conclusions. RBA can depress the intimal hyperplasia and promote dilatation of the artery to greater extents than PTA at 28 days. However, this did not involve TLR-4 signaling pathway, which likely plays a negligible role in mediating restenosis. Reduction of intimal hyperplasia may be due to injury of ablation to the tunica media and inhibition of VSMC proliferation and migration.

scholarly journals Cyclic fatigue resistance of 2Shape, Twisted File and EndoSequence Xpress nickel-titanium rotary files at intracanal temperature

2018 ◽  
Vol 12 (4) ◽  
pp. 283-287 ◽  
Author(s):  
Gülşah Uslu ◽  
Taha Özyürek ◽  
Mustafa Gündoğar ◽  
Koray Yılmaz
Keyword(s):  
Fatigue Resistance ◽  
Statistical Significance ◽  
Cyclic Fatigue ◽  
Nickel Titanium ◽  
Bonferroni Correction ◽  
Significant Difference ◽  
Inner Diameter ◽  
The Difference ◽  
Number Of Cycles ◽  
Analyze Data

Background. The aim of this study was to compare the cyclic fatigue resistance of 2Shape, Twisted File (TF) and EndoSequence Xpress (ESX) nickel-titanium rotary files at intracanal temperature (35°C). Methods. Twenty 2Shape TS1 (25/.04), 20 TF (25/.04) and 20 ESX (25/.04) files were tested for cyclic fatigue at intracanal temperature (35°C). All the instruments were rotated in artificial canals which were made of stainless steel with an inner diameter of 1.5 mm, 60° angle of curvature and a radius curvature of 5 mm until fracture occurred; the time to fracture was recorded in seconds using a digital chronometer and the number of cycles to fracture (NCF) for each file was calculated. Kruskal-Wallis test with Bonferroni correction was performed to statistically analyze data using SPSS 21.0. Statistical significance was set at P<0.05. Results. NCF values revealed that the 2Shape had significantly the highest cyclic fatigue resistance, followed by TF and ESX at intracanal temperature (P<0.05). The difference was significant between the TF and ESX groups (P<0.05). There was no significant difference among the 2Shape, TF and ESX files with respect to the lengths of the fractured file fragments (P>.05). Conclusion. Within the limitations of present study, it was concluded that the cyclic fatigue resistance of 2Shape files at the intracanal temperature is higher than that of TF and ESX files.

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