Effects of Stent Design Parameters on Radial Force of Stent

2008 ◽  
Author(s):  
Xiang Shen ◽  
Hong Yi ◽  
Zhonghua Ni
Keyword(s):  
Radial Force ◽  
Design Parameters ◽  
Stent Design

The Role of Stent Design and Polymers in Safety Outcomes – A Review

2012 ◽  
Vol 8 (1) ◽  
pp. 63
Author(s):  
Carlo Zivelonghi ◽  
Giulia Geremia ◽  
Michele Pighi ◽  
Flavio Ribichini ◽  
◽  
...  
Keyword(s):  
Clinical Performance ◽  
Drug Carrier ◽  
Chemical Properties ◽  
Vascular Wall ◽  
Radial Force ◽  
Vascular Trauma ◽  
Polymer Composition ◽  
Drug Eluting Stent ◽  
Stent Design ◽  
Drug Elution

Each component of a drug-eluting stent (DES) contributes to the safety of the device. Continuous efforts are being dedicated to the search of the optimal compromise between facility of use, safety and long-term efficacy. Shorter balloons reduce the vascular trauma beyond the stent struts; the metallic composition of the stent platform and the platform itself interact with the vascular wall in a long-lasting equilibrium between radial force, vessel patency and reparative cellular regrowth. The modality of drug elution is largely regulated by the chosen drug carrier, rather than by the chemical properties of the drug itself. Drug elution can be accomplished by permanent polymers that remain in the vessel wall forever, by biodegradable polymers that leave the naked metallic structure behind after their complete absorption, or even by direct release of the drug from stent reservoirs. The clinical performance of DESs has been exhaustively assessed in a large number of studies that have showed rapid and continuous improvements, from the first-generation DESs to the latest devices, based on substantial changes in stent design and polymer composition.

Suggestion of Potential Stent Design Parameters to Reduce Restenosis Risk driven by Foreshortening or Dogboning due to Non-uniform Balloon-Stent Expansion

2008 ◽  
Vol 36 (7) ◽  
pp. 1118-1129 ◽  
Author(s):  
Dohyung Lim ◽  
Seung-Kwan Cho ◽  
Won-Pil Park ◽  
Anders Kristensson ◽  
Jai-Young Ko ◽  
...  
Keyword(s):  
Design Parameters ◽  
Stent Design ◽  
Stent Expansion

scholarly journals Impact of Geometry Effects on Artery Stent Deployment Characteristics

2019 ◽  
Vol 9 (2) ◽  
pp. 2029-2035
Keyword(s):  
Heart Diseases ◽  
Research Work ◽  
Computational Method ◽  
Design Parameters ◽  
Stent Design ◽  
Elastic Recoil ◽  
Stent Deployment ◽  
Strut Thickness ◽  
Maximum Expansion

Intravascular stenting is the leading treatment procedure for atherosclerotic coronary heart diseases. Among the various procedures, it is simpler and faster with a high initial success rate. Stent design, stent material, and clinical procedure decide the efficacy and life of stents. Strut thickness and crown radius are two essential design parameters that dictate expansion characteristics of stents. This research work discusses computational analysis of a specific stent, to explore the influence of thickness of strut on the deployment characteristics like stress/strain, foreshortening, recoil, and dog boning. The optimum stent design is one which gives maximum expansion with minimum stress distribution, dogboning, and elastic recoil. Five similar stent models with thickness ranges from 65μ to 105µ were modeled and computational method was adopted to simulate the transitory expansion nature of stent/balloon system. The FE results were substantiated with an in-vitro experiment. It was found that strut thickness has a major impact on stent recoil and low impact on foreshortening and dogboning. Foreshortening per unit expansion was almost same for entire models. Strut thickness 70μ to 80μ gives better expansion characteristics for the model under study.

A Parametric Analysis of Endovascular Stent Geometry Manipulation On Radial Force Performance

2020 ◽  
Author(s):  
Joel C. R. Scott ◽  
Darrel A. Doman ◽  
Clifton R. Johnston
Keyword(s):  
Radial Force ◽  
Wire Diameter ◽  
Force Generation ◽  
Patient Specific ◽  
Bend Angle ◽  
Parameter Study ◽  
Stent Design ◽  
Leg Length ◽  
Bend Radius ◽  
The Impact

Abstract Stents were manufactured to investigate the impact of altering stent design characteristics (leg length, bend angle, bend radius, wire diameter) on radial force generation. Results from this design parameter study showed that leg length, bend angle and wire diameter have a statistically significant impact on radial force generation, while lesser changes in bend radius did not (1.00mm vs. the original 0.794mm [1/32in]). However a larger variation of this parameter (1.588mm [1/16in]) was statistically significant. Results gathered for all parameters were used in the creation of a prototypal software. Using input values of patient specific arterial diameter and compliance, as well as stent design characteristic dimensions, this program has been developed to predict stent radial force at varying levels of expansion.

Effect of Stent Design Parameters on Coronary Artery Flow

2009 ◽  
Author(s):  
Satyaprakash Karri ◽  
Stephen Peter ◽  
Pavlos P. Vlachos
Keyword(s):  
Thrombus Formation ◽  
Design Parameters ◽  
Radius Of Curvature ◽  
Stent Design ◽  
Endovascular Stents ◽  
Long Term Performance ◽  
Artery Flow ◽  
Term Performance ◽  
Realistic Geometries

The most widely accepted modality for treating diseased arteries is the implantation of endovascular stents. Stents are metallic wireframe devices used to reopen clogged arteries. Despite their widespread use, problems persist post-implantation of these devices beginning with sub-acute thrombus formation followed by inflammation, proliferation and remodeling [1]. The specific stent design and its design parameters profoundly impact the hemodynamic environment of the stent [2], in turn affecting thrombus accumulation between struts and thus restenosis [3]. Prior research examining the hemodynamic effects of stents has been performed in simplified geometries [4] however the effects of stent design parameters such as strut thickness and crown radius of curvature or analysis in realistic geometries is generally lacking. A more thorough understanding of the effect of a stent’s geometric parameters on the arterial flow will provide insight into their long-term performance and will lead to better design.

Stent design parameters and crimpability

2016 ◽  
Vol 223 ◽  
pp. 552-553 ◽  
Author(s):  
Gideon Praveen Kumar ◽  
Fangsen Cui
Keyword(s):  
Design Parameters ◽  
Stent Design

Effects of Stent Design Parameters on Normal Artery Wall Mechanics

2006 ◽  
Vol 128 (5) ◽  
pp. 757-765 ◽  
Author(s):  
Julian Bedoya ◽  
Clark A. Meyer ◽  
Lucas H. Timmins ◽  
Michael R. Moreno ◽  
James E. Moore
Keyword(s):  
Radial Displacement ◽  
Design Parameters ◽  
Radius Of Curvature ◽  
Stent Design ◽  
Artery Wall ◽  
Element Analysis ◽  
Radial Strength ◽  
Stent Strut ◽  
Invasive Techniques ◽  
Normal Artery

A stent is a device designed to restore flow through constricted arteries. These tubular scaffold devices are delivered to the afflicted region and deployed using minimally invasive techniques. Stents must have sufficient radial strength to prop the diseased artery open. The presence of a stent can subject the artery to abnormally high stresses that can trigger adverse biologic responses culminating in restenosis. The primary aim of this investigation was to investigate the effects of varying stent “design parameters” on the stress field induced in the normal artery wall and the radial displacement achieved by the stent. The generic stent models were designed to represent a sample of the attributes incorporated in present commercially available stents. Each stent was deployed in a homogeneous, nonlinear hyperelastic artery model and evaluated using commercially available finite element analysis software. Of the designs investigated herein, those employing large axial strut spacing, blunted corners, and higher amplitudes in the ring segments induced high circumferential stresses over smaller areas of the artery’s inner surface than all other configurations. Axial strut spacing was the dominant parameter in this study, i.e., all designs employing a small stent strut spacing induced higher stresses over larger areas than designs employing the large strut spacing. Increasing either radius of curvature or strut amplitude generally resulted in smaller areas exposed to high stresses. At larger strut spacing, sensitivity to radius of curvature was increased in comparison to the small strut spacing. With the larger strut spacing designs, the effects of varying amplitude could be offset by varying the radius of curvature and vice versa. The range of minimum radial displacements from the unstented diastolic radius observed among all designs was less than 90μm. Evidence presented herein suggests that stent designs incorporating large axial strut spacing, blunted corners at bends, and higher amplitudes exposed smaller regions of the artery to high stresses, while maintaining a radial displacement that should be sufficient to restore adequate flow.

Effects of Metal Material Stent Design Parameters on Longitudinal Stent Strength

2016 ◽  
Vol 723 ◽  
pp. 299-304 ◽  
Author(s):  
Xiang Shen ◽  
Zhong Min Xie ◽  
Yong Quan Deng ◽  
Song Ji
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Blood Vessel ◽  
Design Parameters ◽  
Curvature Radius ◽  
Stent Design ◽  
Rigid Surface ◽  
Stent Deployment ◽  
Metal Material ◽  
Stent Deformation

The longitudinal stent deformation (LSD) was usually caused by the external force in the blood vessel. The effects of metal material stent design parameters on the longitudinal stent strength (LSS) were studied using finite element method (FEA). A longitudinal stent compression model was developed and a rigid surface was used to compress the stent after stent deployment in coronary arteries. Results showed that the connector length, the strut amplitude and the curvature radius at the crown junctions influenced the LSS hardly. However, the number of connector played the most significant role in the LSS, and increasing the number of connectors can substantially improve the LSS, and the LSS of stent with four connectors was nearly three times than that of the stent with two connectors. For the shape of connector, the LSS of the S-stent, M-stent and L-stent were successively increased. With regard to the L-stent, increasing the width of connector can improve the LSS. Reasonably changing stent design parameters can effectively strengthen the LSS. Conclusions obtained from this paper can help surgeons to select appropriate stents and designers to optimize the stent design to reduce the LSD.

Expansion Performance of Novel Balloon-Expandable Stent for Tapered Vessel

2015 ◽  
Vol 645-646 ◽  
pp. 1333-1338
Author(s):  
Xiang Shen ◽  
Yang Yang Sun ◽  
Bo Bo Wu
Keyword(s):  
Finite Element Method ◽  
Radial Displacement ◽  
Design Parameters ◽  
The Novel ◽  
Stent Design ◽  
Positioning Accuracy ◽  
Stent Restenosis ◽  
Expansion Pressure ◽  
Stent Expansion ◽  
In Stent Restenosis

In-stent restenosis still remains an obsession to cardiologist, especially in tapered vessels. In this paper, we designed a novel balloon-expandable stent for tapered vessel and proposed a finite element method (FEM) to study the expansion of the novel stent. The effect of stent design parameters on stent tapering and foreshortening were also researched. Results show that the radial displacement of stent proximal end was always larger than that of stent distal end during stent expansion, and the stent had a tapered shape as a whole after expansion. The degree of stent tapering observed increased with the expansion pressure increase. Besides, increasing the gradient of ring amplitude not only could increase the tapering degree of stent after expansion, but also could decrease stent foreshortening, improving the positioning accuracy after stent implantation. In conclusion, FEM can quantify expansion performance of novel balloon-expandable stents and help designers to devise and assess new stent designs for tapered vessel.

scholarly journals Optimization of stent designs regarding the thrombosis risk using computational fluid dynamics

2018 ◽  
Vol 4 (1) ◽  
pp. 93-96
Author(s):  
Carolin Wüstenhagen ◽  
Sylvia Pfensig ◽  
Stefan Siewert ◽  
Sebastian Kaule ◽  
Niels Grabow ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Shear Stress ◽  
Wall Shear Stress ◽  
Stent Thrombosis ◽  
Fluid Simulation ◽  
Design Parameters ◽  
Stent Design ◽  
Thrombosis Risk ◽  
Wall Shear

AbstractIn-stent thrombosis is a major complication of stent implantations. Unlike pathological occurrences as in-stent restenosis for instance, thrombosis represents an acute event associated with high mortality rates. Experiments show that low wall shear stress promotes undirected endothelial cell coverage of the vessel wall and therefore increases the risk of thrombus formation. Stent design represents a crucial factor influencing the surface areas of low wall shear stress and thus the incidence of acute in-stent thrombosis. In this study, we present an optimization method for stent designs with minimized thrombosis risk. A generic stent design was developed, based on five different stent design parameters. Optimization was conducted based on computational fluid dynamics analysis and the gradient-free Nelder-Mead approach. For each optimization step, a numerical fluid simulation was performed in a vessel with a reference vessel diameter of 2.70 mm with stent-overexpansion ratio of 1.0:1.1. For each numerical fluid simulation a physiological Reynolds number of 250, resulting in a mean velocity of 0.331 m/s at the inlet and a laminar flow as well as stiff vessel walls were assumed. The impact of different stent designs was analyzed based on the wall shear stress distribution. As a basis for the comparison of different stent designs, a dimensionless thrombosis risk number was calculated from the area of low wall shear stress and the overall stented area. The first two optimization steps already provide a decrease of thrombosis risk of approximately 83%. In conclusion, computational fluid dynamic analyses and optimization methods usind the Nelder-Mead approach represent a useful tool for the development of hemodynamically optimized stent designs with minimized thrombosis risk.

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