血管内支架构型变化对血流动力学及支架内再狭窄形成的影响  

The effect of stent structure changes on the hemodynamics and the formation of in-stent restenosis

作　　者：吴瑕[1] 徐克[1] 肖亮[1] 张曦彤[1] 苏红英[1] 冯博[1] 

机构地区：[1]中国医科大学附属第一医院放射科,沈阳110001

出　　处：《介入放射学杂志》2009年第4期297-300,共4页Journal of Interventional Radiology

基　　金：国家科技支撑计划课题(编号:2007BAI05B04)

摘　　要：目的研究血管内支架的构型变化对血管壁面剪切力、血流速度及流动方式的作用,探讨支架构型对于支架内再狭窄形成的影响。方法应用三维实体建模软件Pro/engineer wildfire3.0建立5种支架模型,其中A为对照组,B加入横向连接结构,C加入纵向连接结构,D的支架厚度为A的2倍,E的网格密度为A的2倍,将其导入计算流体动力学(computational fluid dynamics,CFD)软件Ansys11.0-CFX,建立流体模型。设定边界条件后进行计算流体动力学分析,比较不同构型的支架植入后引起的血管壁面剪切力、管腔内血流速度及流动方式的变化。结果支架模型A、B、C、D、E植入后血管壁面低剪切力区域所占比率分别为:7.78%、6.65%、1.48%、16.52%、12.12%,D、E的低剪切力区域比率明显大于A,B的低剪切力区域比率明显小于A。支架横截面流速矢量(velocity vector)图显示,D、E中的血流低流速涡流区明显大于A,C中低流速涡流区明显小于A。结论支架构型变化能够引起植入血管血流动力学的明显改变,支架厚度和(或)网格密度增加是引起低剪切力区形成的主要因素,能够促进支架内再狭窄的发生,在支架中加入纵向连接结构能明显减少低剪切力区,可以降低再狭窄形成概率。Objective To investigate the effect of stent structure changes on the formation of in-stent restenosis by studying the influence of these changes on the shear force to the vascular wall, on the velocity of flow and on the flow pattern. Methods Five stent models were established by using Pro/engineer wildfire 3.0. Model A was regarded as control structure. On the base structure of model A, transverse link component was added to form model B, and vertical link component was added to form model C. The thickness of model D was twice than that of model A, and the meshes density of model E was twice than that of model A. Fluid models were built up by importing these stent models into computational fluid dynamics （CFD） software ansys11.0-CFX, then, CFD analysis was proceeded to study the effect of stent structure on hemodynamics. Results After the stents were implanted, the percentage of low wall shear stress on the surface of model A, B, C, D and E was 7.78%, 6.65%, 1.48%, 16.52% and 12.12%, respectively. The percentage of D and E was obviously larger than that of A, while the percentage of B was markedly smaller than that of A. The velocity vector on the cross-sectional planes showed that the low velocity and eddy areas in D and E were much larger than that in A, while this area in C was smaller than that in A. Conclusion The stent structure changes can cause obvious changes in hemodynamics in the implanted vessels. The increase in the thickness and meshes density of the stent is the main factor that induces the formation of low wall shear stress, which will precipitate the development of in-stent restenosis. The added vertical link component will reduce the area of low wall shear stress as well as the occurrence of in-stent restenosis.

关 键 词：支架 血流动力学 再狭窄 计算流体动力学 

分 类 号：R543[医药卫生—心血管疾病]