TCT-564 Biodegradable-Polymer Biolimus Eluting Stents Show Better Antiproliferative Efficacy And Vascular Healing Pattern Than Permanent-Polymer Paclitaxel Eluting Stents in a Preclinical Coronary Model

Abstract

Background: Second-generation drug eluting stents (DES) have shown a high efficacy in terms of restenosis prevention, like first-generation DES, with reduced rates of stent thrombosis, especially late stent thrombosis. The suggested mechanism for this superiority is a better morphological and functional healing response. The objective of this study is to compare the efficacy and safety results of 2 different, first and second-generation, DES in a swine model of normal coronary arteries. Methods: In 9 domestic juvenile swine (25 3 kg), one stent per coronary artery was implanted with an intended stent-to-artery ratio 1.1. We used 9 bare metal stents (BMS), 9 permanent-polymer paclitaxel eluting stents (PES) and 9 biodegradable-polymer biolimus eluting stents (BES). Quantitative coronary angiography was performed after 28 days to assess the in-stent % stenosis and the endothelium-dependent vasomotor response of the distal vessel (Acetylcholine 10-6M). We performed morphometric analyses of the in-stent % area stenosis and the endothelialization rate (haematoxylin-eosin stain, extent of luminal surface coverage with endothelial cells) at 3 levels of each stent sample. The eNOS endothelialization index measures the proportion of the whole luminal surface covered by eNOS endothelial cells. Results: All the stents were implanted as per-protocol, with a final stent:artery ratio 1.17 0.15. No baseline differences were observed between groups. The Table shows the restenosis and the functional healing parameters analyzed in each group.