Investigation of Strut Thickness in Coronary Stents via Finite Element Analysis

Strut thickness in coronary stents has been shown to affect their clinical performance. The purpose of this investigation was to understand how stent strut thickness influenced stress in the vessel wall. Finite element modeling was used to compare stress distribution between a thick and thin strut stent in a curved coronary artery model. Specifically, we modeled two 8 mm long Guidant MULTI-LINK VISION stents, one with strut thickness of 81 μm and the other with strut thickness of 112 μm. Results showed larger values of stress, both in the radial direction and in the circumferential direction, for the thicker stent model. As expected, these higher stress values occurred beneath the stent struts and at the edges of the stent. Stented vessel compliance measurements of both models revealed that the thick strut VISION stent is less compliant than the thin strut VISION stent. These results support the hypothesis that compliance mismatch between the stent and the host vessel contributes to excessive stress in the walls of stented vessels.