Stented artery biomechanics and device design optimization

Abstract

The deployment of a vascular stent aims to increase lumen diameter for the restoration of blood flow, but the accompanied alterations in the mechanical environment possibly affect the long-term patency of these devices. The primary aim of this investigation was to develop an algorithm to optimize stent design, allowing for consideration of competing solid mechanical concerns (wall stress, lumen gain, and cyclic deflection). Finite element modeling (FEM) was used to estimate artery wall stress and systolic/diastolic geometries, from which single parameter outputs were derived expressing stress, lumen gain, and cyclic artery wall deflection. An optimization scheme was developed using Lagrangian interpolation elements that sought to minimize the sum of these outputs, with weighting coefficients. Varying the weighting coefficients results in stent designs that prioritize one output over another. The accuracy of the algorithm was confirmed by evaluating the resulting outputs of the optimized geometries using FEM. The capacity of the optimization algorithm to identify optimal geometries and their resulting mechanical measures was retained over a wide range of weighting coefficients. The variety of stent designs identified provides general guidelines that have potential clinical use (i.e., lesion-specific stenting).

Sequential Structural and Fluid Dynamics Analysis of Balloon-Expandable Coronary Stents: A Multivariable Statistical Analysis

“…These computational methods of analysis employ sophisticated numerical techniques, such as the finite element and finite volume methods, to obtain approximate numerical solutions to complex physical problems. To date, a large number of studies have carried out computational structural (CS) analyses 1,4,5,14,15,19,[25][26][27][28][29]37,44,53,54,57,59,[62][63][64]72,73,78,80,85,87,[90][91][92] and computational fluid dynamics (CFD) analyses 3,8,9,12,30,31,33,42,[47][48][49][50][51]65,66,69,[74][75][76]83,89 ...…”

Application of a mechanobiological simulation technique to stents used clinically

“…Bedoya et al (2006) and Timmins et al (2007) optimised stent designs by minimising the volume of tissue stressed above a critical threshold. This approach attempts to capture restenosis by predicting the regions where adverse biological reactions are likely to occur.…”

Determination of the influence of stent strut thickness using the finite element method: implications for vascular injury and in-stent restenosis

“…Two main approaches have been adopted to reduce instent restenosis; (1) optimising the stent design to reduce vascular injury and hence subsequent neointimal hyperplasia [17,26], and (2) using anti-proliferative drug eluting stents to inhibit the growth of neointimal hyperplasia [8]. The delivery of an anti-proliferative drug to surrounding tissue is also significantly influenced by the stent design [11].…”