血管支架内壁面圆形凹坑微织构对血流动力学影响仿真

Simulation of the Effect of Circular Pit Micro Texture on Hemodynamics on the Inner Wall of Vascular Stent

为降低血管支架置入后出现再狭窄现象的概率,改善支架内血液的流动特性,本文基于仿生学原理,在网状/管状血管支架内表面设计直径为60μm,深度分别为30μm、50μm和70μm的圆形凹坑织构。采用有限元仿真分析方法探究不同支架结构和深度的微织构对支架内血液流动速度和血管内压力的影响。结果表明,与管状支架相比,网状支架内壁微织构的存在能够大幅提高支架内血液流动速度,增大血液的压力,尤其是当深度为30μm和50μm时更为明显。此外,相同条件下,网状血管支架内血压的最大变化幅度小于管状支架内血压的最大变化幅度,对血管壁造成的损伤更小。

Stent interventional surgery has become the first choice for the treatment of cardiovascular and cerebrovascular diseases,but the high rate of restenosis after stent implantation makes the long-term treatment effect unsatisfactory.In order to reduce the probability of restenosis after stent implantation and to improve the blood flow characteristics in the stent,based on the principle of bionics,the inner surface of the reticular/tubular vascular stent is designed on round pit texture with the diameter of 60μm and the depth of 30μm,50μm and 70μm,respectively.The finite element simulation analysis method is used to explore the influence of different stent structures and depths of micro texture on the blood flow velocity and intravascular pressure in the stent.The results show that,compared with tubular stents,the presence of micro texture on the inner wall of the reticular stent can greatly increase the blood flow velocity in the stent and increase the blood pressure,especially when the depth is 30μm and 50μm.In addition,under the same conditions,the maximum change range of blood pressure in the reticular stent is smaller than the maximum change range of blood pressure in the tubular stent,which causes less damage to the blood vessel wall.