Effects of stent design parameters on normal artery wall mechanics
Effects of stent design parameters on normal artery wall mechanics
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DOI：
10.1115/1.2246236
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发表时间：
2006-10-01
影响因子：
1.7
通讯作者：
Moore, James E., Jr.
中科院分区：
文献类型：
--
作者：
Bedoya, Julian;Meyer, Clark A.;Moore, James E., Jr.
支架是一种旨在恢复狭窄动脉血流的装置。这些管状支架装置被输送到患病区域并使用微创技术进行部署。支架必须具有足够的径向强度以支撑病变动脉张开。支架的存在会使动脉承受异常高的压力，从而引发不良的生物反应，最终导致再狭窄。这项研究的主要目的是研究不同支架“设计参数”对正常动脉壁引起的应力场以及支架实现的径向位移的影响。通用支架模型被设计为代表目前市售支架中所包含的属性的样本。每个支架均部署在均匀的非线性超弹性动脉模型中，并使用市售有限元分析软件进行评估。在本文研究的设计中，与所有其他配置相比，那些在环段中采用大轴向支柱间距、钝角和较高振幅的设计在动脉内表面的较小区域上引起高周向应力。轴向支柱间距是本研究中的主要参数，即所有采用小支架支柱间距的设计都比采用大支柱间距的设计在更大的区域上引起更高的应力。增加曲率半径或支柱振幅通常会导致承受高应力的区域变小。与小支柱间距相比，在较大支柱间距时，对曲率半径的敏感性增加。对于较大的支柱间距设计，可以通过改变曲率半径来抵消变化幅度的影响，反之亦然。在所有设计中观察到的无支架舒张半径的最小径向位移范围小于 90 μm。本文提供的证据表明，结合大轴向支柱间距、弯曲处钝角和较高振幅的支架设计使动脉的较小区域暴露于高应力，同时保持足以恢复足够血流的径向位移。
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 90 mu m. 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.