The Influence of Arterial Wall Thickness on Stainless Steel Material Stent Expansion in Tapered Arteries

The implantation of an intravascular stent has become a common and widely used minimally invasive treatment for coronary heart disease. But in-stent restenosis (ISR) after stent implantation, especially in tapered vessels, limits the clinical success of stents. In this study, the finite element method (FEM) has been carried out to study the effects of vessel wall thickness on 316L stainless steel stent deployment in tapered arteries. The influence of arterial wall thickness was demonstrated by combination of varied wall thickness and constant wall thickness case. Results indicated that compared to a vessel model with varied thickness from proximal end to distal end, a vessel model with constant thickness had higher vessel wall stress induced by stent expansion. Thus the injury level of vessel wall during stent expansion was overestimated. Numerical simulation results from this study are beneficial to construct a reasonable and accurate expansion model of stent in tapered vessels. The FEM can quantify mechanical properties of stents in tapered vessels, and can compare different modeling strategies for vessel wall thickness, and assist designers to develop new stents especially for tapered vessels.