脉动流下血管支架耦合系统血流动力学实验研究

Hemodynamics Experimental Research of Stent Coupling System of Pulse Flow

为了探究血流动力学性能对再狭窄的影响,本文介绍了一种基于圆柱形内壁模型的血管支架耦合系统血流动力学性能的测试方法,并根据此方法自行设计并搭建一套实验装置,通过此装置对本实验室自制的冠脉支架进行了血流动力学性能测试实验。实验在脉动流下进行,实验结果表明,一个脉动周期内,靠近壁面的粒子运动速度先增大后减小,且速度总体数值很小;在同一时刻随着离壁面距离的增大,速度一直呈递增的趋势;在距离壁面同一位置处,速度随时间先增大后趋于平缓,在周期末尾时急剧下降到零,并伴有回流现象。通过计算壁面剪应力发现,一个周期内,壁面剪应力随时间变化先增大后减小;低于0.4Pa的时间占整个周期的一半,且分布在周期的开端和末端,是容易发生再狭窄的时间区分布。本实验对后续血流动力学性能测量提供了一定的实验基础,并且对后期支架的设计和优化提供了验证的手段。

In this report, we presented a novel approach for hemodynamics study of stent coupling system based on cylindrical inner wall model to investigate the effect of hemodynamic performance on restenosis. A set of experimental apparatus has been assembled based on this approach. Coronary artery stent that designed by our lab was used in the hemodynamics experimental research which was done in pulsating flow. The hemodynamics experimental research results showed that the velocities of particles near the wall increase at first then decreases and the overall speed is small. With the increase of distance, velocity has been increased. Velocity increased from the bottom to the peak value, after which became flat and swooped suddenly to the bottom, with the time passed in a pulsation period. Countercurrent has been captured towards the end of pulsation period. The calculation results have shown that wall shear stress increases with time then decrease. The lasting of wall shear stress which was lower than 0.4Pa accounted for half of the pulsation period and distributed at the beginning and end of the cycle which is prone to restenosis. Consequently, the study not only provided a basis for the subsequent measurement of hemodynamic performance but also supplied artifice that provides verification for the design and optimization of stents.