Compliance and Longitudinal Strain of Cardiovascular Stents: Influence of Cell Geometry

Abstract

A systematic study on the influence of the cell geometry of a cardiovascular stent on its radial compliance and longitudinal strain is presented. Eight stent cell geometries—based on common lattice cells—are compared using finite element analysis. It is found that, for a given strut thickness, the radial compliance depends on the shape of the cell and is intimately connected with the longitudinal strain through effective Poisson’s ratio, which depends on the cell geometry. It is demonstrated experimentally that a hybrid stent containing both positive and negative Poisson’s ratio cell lattice geometries exhibited very low values of longitudinal strain. This study indicates that cell geometries may be tailored to minimize longitudinal stresses imposed by the stent onto the artery wall.