Determining the Impact of Geometry Effects on Artery Stent Deployment Characteristics

Abstract

This research work discusses computational analysis of a specific stent, to explore the influence of thickness of strut on the deployment characteristics like stress/strain, foreshortening, recoil, and dog boning. Congestive heart failure is one of the leading causes of death for millions of people around the world each year. The deposition of celluloid or calcified plaque on the arterial wall causes a stoppage in blood flow (stenosis), which can lead to a heart attack. Intravascular stenting is the leading treatment procedure for atherosclerotic coronary heart diseases. Among the various procedures, it is simpler and faster with a high initial success rate. Stent design, stent material, and clinical procedure decide the efficacy and life of stents. Strut thickness and crown radius are two essential design parameters that dictate expansion characteristics of stents. The optimum stent design is one which gives maximum expansion with minimum stress distribution, dogboning, and elastic recoil. Five similar stent models with thickness ranges from 65\(\mu\) to 105\(\mu\) were modeled and computational method was adopted to simulate the transitory expansion nature of stent/balloon system. The FE results were substantiated with an in-vitro experiment. It was found that strut thickness has a major impact on stent recoil and low impact on foreshortening and dogboning. Foreshortening per unit expansion was almost same for entire models. Strut thickness 70\(\mu\) to 80\(\mu\) gives better expansion characteristics for the model under study.