The Structure And Optimization Of PDO Intravascular Stent By Finite Element Analysis

As living standards go up,coronary heart disease,coronary atherosclerosis and other cardiovascular diseases have become the important factors to affect the human health.Bioabsorbable intravascular stents have been heralded as the fourth revolution in the treatment of coronary atherosclerosis diseases.The existing biomaterial intravascular stents have proved to have a good effect in treating coronary atherosclerosis diseases,but many problems,such as the shortage in radial strength and the degradation period for too long,occurred in the clinical treatment of these stents.Therefore,it is of great importance to find out a new biomaterial stent which may solve the long degradation period and the insufficient radial strength.This paper aimed to research the structure of polydioxanone(PDO)intravascular stent and was to optimize its structure.PDO had proven to be a good biomaterial in making a stent which had strong radial strength and an ideal degradation period,because PDO material had high Young's modulus and was easily absorbed.The stents,braided using PDO monofilament,were successful in curing tracheal narrowing,refractory benign esophageal stricture and colon anastomotic stricture.This paper started by investigating the structural characteristics of PDO intravascular stent,and then researched and analyzed the relations between the radial strength of PDO intravascular stent and the structural parameters.Simultaneously,based on the relations between the radial strength and the structural parameters,the structure of the optimal stent whose radial strength reached to the standard of coronary stent was found out.This paper used the method of combination of finite element analysis and experiment to analyze the relation among the radial strength of stent and the internal diameter of stent,the monofilament diameter of stent,the height of crown,the length of crown and the radian of crown.A function which was composed of the radial strength of PDO intravascular stent,the internal diameter,the monofilament diameter was fitted by Matlab,and the other function about the radial strength of PDO intravascular stent and the height,length,and radian of crown was also fitted by Matlab.According to these two functions,the structural parameter values of the optimal stent were found out,simply.A new method was proposed to found out the optimal structure when considering multi-parameter during optimization.The research significance of this paper made a series of studies to the international difficult problem of how to enhance the radial strength of biodegradable stent,and provided the guidance for further researches on enhancing the radial stent of biodegradable stent.This paper researching provides a theory basis for our country to develop and produce with independent intellectual property rights of the biodegradable stent products.