The Simulation And Research Of Stents About Biomechanical Property In Arterial Stenosis

Coronary heart disease is most common in cardiovascular disease, coronary artery stent implantation become the most popular method among all the therapies. There are traditional metal stents, drug eluting stents and biodegradable stents at present, thereinto, magnesium alloy stents get favor from many researchers due to his degradation characteristics. Magnesium alloy stents has well mechanical properties and biocompatibility, but it is easy to collapse because the strong brittleness. Getting stress distribution and corresponding mechanical properties using finite element method to simulate and analysis the different construction stents, including:(1)Doing finite element analysis with three stents which have same support structure and different connection structure under two cases: without vessel and with vessel. Result shows: Stress distribution of free expansion model and coupling expansion model almost the same, no obvious change; Axial shortening rate of free expansion model is bigger than coupling expansion model’s, radial springback rate is smaller, expansion nonuniform is obvious; Safety factor shows no significant change between this two models.(2)Doing finite element analysis under vessel with three stents that first part used, put every stent three different expansion diameters: 2.6mm 2.8mm and 3.0mm,make a contrast with stress and strain distribution, mechanical property in this three cases for every stent. Result shows: with the increase of the expansion diameters, every stents’ stress and strain increase too, but the maximum distribution area has no change; Axial shortening rate and expansion nonuniform are increasing, radial springback rate is decreasing, safety factor is decreasing for every stent.(3)Doing finite element analysis under three different rate of stenosis 30% 40% 50%,with two open loop structure magnesium alloy stents which have same support structure and different connection structure, so as to two closed loop structure magnesium alloy stents having same support structure and different connection structure. Result shows: with the increase of the rate of stenosis, three is no obvious change in the distribution of stress and strain;for every stent, axial shortening rate is decreasing, radial springback rate and expansion nonuni-form are increasing. What is more, vessels’ stress from open loop structure stents is bigger than the one from closed loop structure stents.Getting distribution of stress and strain or the mechanical properties through finite element analysis with three models: free expansion models, coupling expansion with vessel and coupling expansion with stenosis arterial, providing the reference basis for designing and analyzing with magnesium alloy stents.