Biomechanical Performance of Coronary Stents Investigated through the Finite Element Method

Abstract

Restenosis is a re-narrowing or blockage of an artery at the same site where treatment, such as a balloon angioplasty or stent procedure, has already taken place. Several clinical trials have shown a significant reduction in the restenosis rates with endovascular stenting. Intravascular stents are small tube-like structures expanded into stenotic arteries to restore blood flow perfusion to the downstream tissues. However, stenting can cause a vascular injury during the deployment. Hence, the stent expansion defines the effectiveness of the surgical procedure: it depends on the stent geometry, it includes large displacements and deformations and material non-linearity. In this paper, the finite element method is applied to investigate the biomechanical performance such as radial and longitudinal recoil, foreshortening and dogboning. Furthermore, it is well known that the stent design plays a role in the outcome of the stenting interventional procedure. This study compares the mechanical effects of the expansion of three different designs of balloonexpandable stents in a coronary artery by means of numerical models based on the finite element method. In conclusion, a finite element analysis similar to the one herewith proposed could help in designing new stents or analyzing actual stents to ensure ideal expansion and structural integrity, substituting in vitro experiments often difficult and unpractical.