Integrity of stent polymer layer after drug-eluting stent implantation: in vivo comparison of sirolimus-, paclitaxel-, zotarolimus- and everolimus-eluting stents

Abstract

Few data exist with regard to the polymer integrity of drug-eluting stents (DES) in vivo. This study aims to investigate the integrity of the polymer layer of 4 polymer-coated DES in vivo. We assessed the morphology of the polymer layer of sirolimus-eluting stent (SES; Cypher Select™), paclitaxel-eluting stent (PES; Taxus Liberté™), zotarolimus-eluting stent (ZES; Endeavour RX™) and everolimus-eluting stent (EES; Xience V™) by scanning electron microscopy after balloon expansion at nominal and high pressures in the coronary arteries of 3 pigs. Effects of kissing balloon procedure were also explored. The polymer layer of SES, PES and EES were damaged in less than 3% of the surface area with high pressure procedures, whereas the damaged area reached 38.0±2.6% in ZES (P<0.01). The polymer integrity differed greatly among DES after balloon inflation in vivo. This should be taken into account when placing DES in tortuous vessels, calcified, as well as bifurcation lesions because the polymer layer may be easily damaged in these lesions.