Evaluation of cover effects on bare stent mechanical response

McGrath, Donnacha J.; O’Brien, Barry; Bruzzi, Mark; Kelly, Niall P.; Clauser, Johanna; Steinseifer, Ulrich; McHugh, Peter E.

doi:10.1016/j.jmbbm.2016.04.023

Cited by 28 publications

(17 citation statements)

References 47 publications

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“…As a result of the hard texture of Fluency ePTFE covered stent, longitudinal deformation would take place in the early stage as the stent rebounces after placement, which leads to the increasement of the angle of portalvenous in ow, and it may even cause the twists in the softer BMC outside because of excessive tension. [37] Viabahn ePTFE covered stents are softer, compared to Fluency ePTFE covered stents, and the tension towards the bare stents outside is rather less, so longitudinal deformation is less likely to occur. Thus, the angle of portalvenous in ow would increase after TIPS inplanation in Fluency group but not change in Viabahn group, which is veri ed in this study, after 3 months following TIPS insertion, the angle of portalvenous in ow distinctly increased from 20.9°±14.3° to 26.9°±20.1° (p = 0.005) in Fluency group but stayed unchanged in Viabahn group (from 21.9°±15.1° to 22.9°±17.6°, p = 0.798).…”

Section: Discussionmentioning

confidence: 99%

A New Choice for the Use of the Stents for Transjugular Intrahepatic Portosystemic Shunt Creation: Viabahn ePTFE covered stent/bare metal stent combination

Liu

Meng

Zhou

et al. 2020

Preprint

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Background Compare the clinical outcome of structure and function between insertion of transjugular intrahepatic portosystemic shunt (TIPS) created with the Viabahn ePTFE covered stent/bare metal stent (BMS) combination and Fluency ePTFE covered stent/BMS combination. Methods 101 consecutive patients undergone TIPS procedure from February 2016 to August 2018 in our center were analyzed retrospectively, 64 subjects were enrolled in Viabahn group and 37 were Fluency group. We caculated the TIPS geometry characteristics and evaluated the related occurrence of shunt dysfunction, survival, overt hepatic encephalopathy (OHE) and variceal rebleeding. Results The technical success rate was 100%. After TIPS insertion, the rate of shunt dysfunction during the first 3 months was significantly different between Viabahn group and Fluency group, which were respectively 1.6% and 13.5% (p = 0.024). And multivariate analysis indicated that the angle of portalvenous inflow (α) (HR = 1.060, 95%CI = 1.009–1.112, p = 0.020) was the only predictor of shunt dysfunction. Besides, after 3 months following TIPS insertion, the α angle distinctly increased from 20.9°±14.3° to 26.9°±20.1° (p = 0.005) in Fluency group but stayed unchanged in Viabahn group (from 21.9°±15.1° to 22.9°±17.6°, p = 0.798). Conclusions The occurence of shunt dysfunction was related to the angle of portalvenous inflow (α), because of the slighter effect on α angle, after TIPS inplanation, Viabahn ePTFE covered stent/BMS combination was more stable in structure and promised higher short-term stent patency compared to Fluency ePTFE covered stent/BMS combination.

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Section: Discussionmentioning

confidence: 99%

A New Choice for the Use of the Stents for Transjugular Intrahepatic Portosystemic Shunt Creation: Viabahn ePTFE covered stent/bare metal stent combination

Liu

Meng

Zhou

et al. 2020

Preprint

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“…To avoid complications is essential to know the pathology of tumor stenosis, this includes 3 areas: the most stenotic tumor area where there has been obstruction, tumor mass that precedes and follows the proper obstructed area, and part of anterior intestine and distal, which usually has a significant edema. It is therefore necessary to adapt the design of the stent to the different areas that make up an anatomical area affected by the obstructive tumor, and the peristaltic movement of the intestine that precedes and continues to the tumor area, as the technical success of a stent depend directly on mechanical behavior, which can be estimated through predictive simulation model by FEA [22][23][24][25][26][44][45][46][47] or experimentally like in Isayama et al [20] and Rebelo et al [48] for a braiding stent.…”

Section: Discussionmentioning

confidence: 99%

A methodology for the customized design of colonic stents based on a parametric model

Puértolas

Navallas

Herrera

et al. 2017

Journal of the Mechanical Behavior of Biomedical Materials

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The choice of necessary stent properties depends mainly on the length of the stenosis and degree of occlusion. So a stent design with variable radial stiffness along its longitudinal axis would be a good option. The design proposed corresponds to a tube-based stent with closed diamond-shaped cells made from a NiTi alloy. By acting independently on different geometric factors, variable geometries can be obtained with different radial force reactions. A design adjustment according to specific requirements, in order to get a better fit to ill-duct and reduces complications, is possible. A parametric analysis using finite element has been conducted to determine the influence of slot length, number of circumferential slots, tube thickness and shape-factor on stent mechanical behavior, which allow eliminating the need for extensive experimental work and knowing and quantifying the influence of those factors. The results of finite element simulations have been used, by means of least-squares fit techniques, to obtain analytical expressions for the main mechanical characteristics of the stent (Chronic Expansive Radial Force and Radial Compression Resistance) in terms of the different geometrical factors. This allows the stent geometry to be customized without launching an iterative and costly process of modeling and simulation for each case.

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“…We apply the Cauchy von Mises equivalent stress measure denoted by σ , which is frequently used to asses the stress state in vessels 18,32‐32,69 and SGs 18,70 , where σ describes the stress state after the SG deployment. Instead of considering maximum values of stresses, we use stress percentiles that had been proven to be more suitable in the evaluation of vessel stresses 69,71‐72 .…”

Section: Methodsmentioning

confidence: 99%

In silico study of vessel and stent‐graft parameters on the potential success of endovascular aneurysm repair

Hemmler

Lutz

Reeps

et al. 2019

Numer Methods Biomed Eng

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The variety of stent‐graft (SG) design variables (eg, SG type and degree of SG oversizing) and the complexity of decision making whether a patient is suitable for endovascular aneurysm repair (EVAR) raise the need for the development of predictive tools to assist clinicians in the preinterventional planning phase. Recently, some in silico EVAR methods have been developed to predict the deployed SG configuration. However, only few studies investigated how to assess the in silico EVAR outcome with respect to EVAR complication likelihoods (eg, endoleaks and SG migration). Based on a large literature study, in this contribution, 20 mechanical and geometrical parameters (eg, SG drag force and SG fixation force) are defined to evaluate the quality of the in silico EVAR outcome. For a cohort of n = 146 realizations of parameterized vessel and SG geometries, the in silico EVAR results are studied with respect to these mechanical and geometrical parameters. All degrees of SG oversizing in the range between 5% and 40% are investigated continuously by a computationally efficient parameter continuation approach. The in silico investigations have shown that the mechanical and geometrical parameters are able to indicate candidates at high risk of postinterventional complications. Hence, this study provides the basis for the development of a simulation‐based metric to assess the potential success of EVAR based on engineering parameters.

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Evaluation of cover effects on bare stent mechanical response

Cited by 28 publications

References 47 publications

A New Choice for the Use of the Stents for Transjugular Intrahepatic Portosystemic Shunt Creation: Viabahn ePTFE covered stent/bare metal stent combination

A New Choice for the Use of the Stents for Transjugular Intrahepatic Portosystemic Shunt Creation: Viabahn ePTFE covered stent/bare metal stent combination

A methodology for the customized design of colonic stents based on a parametric model

In silico study of vessel and stent‐graft parameters on the potential success of endovascular aneurysm repair

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