Hemocompatibility of drug-eluting coronary stents coated with sulfonated poly (styrene-block-isobutylene-block-styrene)

Abstract

The presence of polymer coating on a coronary stent is a major mediator of coronary inflammation reaction thereby affects re-endothelialization. Poly(styrene-block-isobutylene-block-styrene) (SIBS) is one of the most attractive alternatives to serve as stent coating, but has shown less than optimal biocompatibility. Increasing the sulfonic acid content in the polymer can result in increased strength and hydrophilicity. The present study was undertaken to determine the mechanism of action and in vivo efficacy of sulfonated SIBS (S-SIBS) designed specifically as a stent polymer with reduced inflammatory potential and greater endothelialization preservation potential. The blood compatibility of S-SIBS in vitro and its ability to support the attachment of human umbilical vein endothelial cells (HUVECs) were first assessed to get some insight into its potential use in vivo. Baer metal stent (BMS), S-SIBS-coated stent without drug (BMS Plus S-SIBS), standard drug-eluting stent (DES) and S-SIBS-coated drug-eluting stent (DES Plus S-SIBS) were then implanted in the coronary arteries of a porcine model. Neointimal hyperplasia was evaluated at 28 and 180 days, and re-endothelialization was evaluated at 7 and 28 days post stents implantation. The results showed that DES Plus S-SIBS exhibited similar ability to reduce neointimal hyperplasia but preserved endothelialization compared with standard DES. These results suggest potentially promising performance of S-SIBS-coated stent in human clinical applications of coronary stenting.