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In order to study the influence of different stenosis rates of blood vessels on the fatigue strength and service life of lower limb arterial stent, numerical simulation was conducted for the mechanical behavior of four types of nickel-titanium alloy lower limb arterial stents (Absolute Pro, Complete SE, E-luminexx-B and Pulsar-35) under the action of radial compression, release and pulsating loads, so as to predict the fatigue life and safety of stents at different stenosis rates (0%, 30%, 50% and 70%). The study found that with increased vascular stenosis rate, both the elastic stress and strain of stent tend to increase, while the fatigue strength, service life and safety tend to decrease. When a stent is implanted in a normal blood vessel, its fatigue strength satisfies the requirement of a 10-year service life requirement, with maximum elastic stress and strain occurring on both sides of the connecting ribs at the end of stent. When the vascular stenosis rate is greater than 30%, the fatigue strength of the stent does not meet requirement of a 10-year service life, and fatigue fracture is likely to occur at the most stenotic part of the blood vessel. With increased vascular stenosis rate, the E-luminexx-B stent with the largest width of support had a significant decrease in its service life. The stent whose supporting unit is of symmetric wave peak structure has a longer service life compared with that whose supporting unit is of offset wave peak structure. The revealing of the influence of vascular stenosis rate on the mechanical properties and fatigue life of stents provides theoretical reference for the fracture failure mechanism of stents.

To explore the influence of bionic texture coronary stents on hemodynamics, a type of bioabsorbable polylactic acid coronary stents was designed, for which a finite element analysis method was used to carry out simulation analysis on blood flow field after the implantation of bionic texture stents with three different shapes (rectangle, triangle and trapezoid), thus revealing the influence of groove shape and size on hemodynamics, and identifying the optimal solution of bionic texture groove. The results showed that the influence of bionic texture grooves of different shapes and sizes on the lower wall shear stress region had a certain regularity. Specifically, the improvement effect of grooves above 0.06 mm on blood flow characteristics was poor, and the effect of grooves below 0.06 mm was good. Furthermore, the smaller the size is, the better the improvement effect is, and the 0.02 mm triangular groove had the best improvement effect. Based on the results of this study, it is expected that bionic texture stents have provided a new method for reducing in-stent restenosis.为探究冠脉支架的仿生织构化处理对血流动力学的影响规律，设计一款生物可吸收聚乳酸冠脉支架，利用有限元分析方法，对三种形状（矩形、三角形和梯形）的仿生织构化的支架植入后血流流场进行仿真分析，揭示沟槽的形状和尺寸对血流动力学的影响规律，并寻求仿生织构化沟槽的最优解。结果显示，不同形状和尺寸的仿生织构化沟槽，对低壁面剪应力区域的影响具有一定的规律性，0.06 mm以上的沟槽对血流流动特性的影响较小，而0.06 mm以下的沟槽对血流流动特性的影响较显著，且随着尺寸的减小影响效果越好，其中0.02 mm的三角形沟槽在研究的所有模型中的影响效果最好。通过本文研究结果，期望仿生织构化支架结构能为降低支架内再狭窄提供一种新方法。.