不同扩张尺度对非对称椎动脉支架力学性能影响的研究

在临床治疗中，不同尺寸的狭窄血管所需要支架扩张的尺度也不同，而支架的扩张尺度对其力学性能有着重要影响。利用有限元方法仿真模拟分析了三款不同支架的体外扩张过程，主要研究了结构相同时不同扩张尺度对支架力学性能的影响。结果显示：随着支架扩张直径的增大，支架的最大等效应力、轴向短缩率、扩张不均匀性及柔顺性能呈递增趋势，支撑刚度和静安全系数呈递减趋势；支架的径向回弹主要受到其材料和结构影响，扩张尺度并不起决定性作用；通过与实验结果相比对，理论值与实验值结果吻合较好，误差在7%以内，验证了有限元模拟的准确性及合理性；利用动物实验对支架治疗效果进行验证，表明了支架的植入治疗是安全且有效的。综合考虑各因素影响，支架的治疗效果受支架扩张尺度的影响较大，这为临床治疗的顺利实施提供了良好的理论依据。

INFLUENCE OF DIFFERENT DILATATION SIZE ON MECHANICAL PROPERTIES OF ASYMMETRIC VERTRBRAL ARTERY STENTS

In clinical treatment, stenosed vertebral arteries with different diameter require different dilatation size of stents. The dilatation size of a stent has a great influence on its mechanical properties. The finite element method was used to simulate and analyse the expansion process in vitro of three different stents to investigate the effect of different dilatation size on stents' mechanical properties with the same structure. Results showed: 1) with the increase in the final expansion diameter of stents, the maximum equivalent stress, axial shortening rate, expansion non-uniformity and flexibility of the three stents had an increasing tendency, while radical bracing stiffness and static safe-value decreased; 2) the radial spring-back of stents was mainly influenced by the material and structure, the dilatation size didn't play the decisive role; 3) comparisons showed that the theoretical and experimental data matched well, and the error values were under 7% which proved the veracity and rationality of the finite element simulation; 4) the treatment effect of stents was verified with animal experiment, and the result showed the implantation of stents was safe and effective. This study proved the dilatation size has a great influence on the treatment effect of stents. In the meantime, it is expected to offer a theoretical basis for the smooth implementation of clinical treatment.