The effect of intrinsic characteristics on mechanical properties of poly(l-lactic acid) bioresorbable vascular stents

Abstract

Poly(L-lactic acid) (PLLA) is currently the bioresorbable polymer of choice for vascular stents with its superior biocompatibility and mechanical properties. However, it is still difficult to enhance the radial supporting capacity of PLLA stents without increasing the strut thickness. In this study, the performance of laser-cut thin-strut stents from two groups of PLLA tubes are investigated. We considered two groups of PLLA tubes. Group 1 indicates the longitudinally stretched from original 150-μm-thick tubes, and Group 2 indicates the directly thinned from original 150-μm-thick tubes. Three stages of mechanical tests were conducted in this study, which are defined as tensile tests of dog-bone specimens, radial loading tests of tubes and radial loading tests of stents. The results suggest that Group 2 has higher radial supporting capacity than Group 1 with the same wall thickness. This work serves as a basis for manufacturing thin-strut stents with sufficient radial supporting capacity.