PLA stereocopolymers as sources of bioresorbable stents: preliminary investigation in rabbit

The aim of the present work was to evaluate whether the degradation of PLA-based bioresorbable stents can be modulated via the configuration of repeating units as it is the case in other applications like osteosynthesis. The first obstacle was finding a stent design that could allow implantation in the aorta of a rabbit taken as a model of a human coronary artery. In the absence of guidelines other than those tentatively proposed in patents, several simple designs were considered that allowed us to evaluate the fate of the stents made of poly(lactic acid) stereocopolymers with L/(L + D) ratio of 0.92 (PLA92) and 0.50 (PLA50) up to 6 months post in vivo implantation. Our findings show the feasibility of bioresorbable stenting using PLA stereocopolymers and that PLA50 degraded faster than PLA92. Therefore, using stereocopolymers appears as a means to vary the degradation rate and adapt it to the artery remodelling process that is very much dependent on the release of the stenting stress protection.