Expansion Simulation Of Coronary Stent And Fluid-structure Interaction Analysis

The world health organization statistics show that cardiovascular disease has become theleading killer of human beings, but coronary atherosclerosis heart disease is the mostthreatening human disease. Coronary stent is implanted in the stenosis or occlusion ofcoronary artery to restore blood flow, which is the most effective way to treat the coronaryheart disease. After intracoronary stent implantation, the human body may appear thephenomenon of in-stent restenosis (ISR), however, ISR seriously influences a curativeeffect of stent implantation. If the process of stent implantation and the serving process ofcoronary stent can be clearly simulated in the human artery, we will learn about themechanical behavior, deformation behavior of coronary stent and the effect on interactionwith lesions vessels during stent implantation, and then the interaction impact with the bloodand artery after stent implantation, etc. It will play a very important role to prevent ISR, andeven conquer ISR.In this paper, undertaking Pro/ENGINEER4.0as a modeling tool, the expansionsimulation of coronary stent and fluid-structure interaction (FSI) analysis are analyzed byANSYS Workbench12.0providing analysis platforms. During the expansion processsimulation of coronary stent, the corners of “U” shape connection rods will experience thelarge deformation of geometric structure and elastic-plastic deformation of materials, andstresses are concentrated upon these areas. The expansion method of a given radialdisplacement can better expand to the nominal diameter of coronary stent, and coronarystent won’t appear the "Dogboning" phenomenon during the expansion process, whichwon’t injury the vascular intima owing to both ends of the upwarp in the process ofstenting. The expansion method can be spread to the research and development of anew-type tool of stent-balloon expansion in order to change the traditional method ofstenting which may induces thrombus problems.Coronary stent will be shorten on the axial direction during expansion process, whichmay cause coronary lesions to be not covered completely and also may induce the longitudinal wall shear stress (WSS) to damage the vascular intima in the vessel. Thewidth size of stent rods is greater than its thickness size in the capability of resistingdeformation of configuration. The radial spring-back of coronary stent directly affects aproblem whether the stent can be accurately located in the regions of coronary lesion.Increasing the width of stent rods, that is increasing contact areas, can reduce theoccurrence of in-stent restenosis (ISR).The coronary stent serves in the human body after stent implantation, and blood aroundstent rods produces separated and reattaching turbulent flow phenomenon. The retentionphenomenon of blood occurs in inner side regions of the stent, and the pressure and wallshear stress (WSS) are much lower in these zones which will cause in-stent restenosis(ISR). When the heart is systolic or diastolic, the radial displacement in the inlet and outletregions of vessel differs in other areas, which can cause vascular intimal hyperplasia.The analysis and research in this article will help the research institution ofcardiovascular stents to design more excellent stents, and make new contributions for thetechnology development of cardiovascular stent and conquering ISR.