In vivo comparison of a polymer‐free Biolimus A9‐eluting stent with a biodegradable polymer‐based Biolimus A9 eluting stent and a bare metal stent in balloon denuded and radiated hypercholesterolemic rabbit iliac arteries

Abstract

To evaluate the effect of a polymer-free Biolimus A9-eluting stent [BioFreedom (BF)], compared with that of a biodegradable polymer-based Biolimus A9-eluting stent [BioMatrix Flex (BMF)] and a bare metal stent (BMS) in balloon denuded and radiated hypercholesterolemic rabbit iliac arteries. Rabbits were fed with 1% cholesterol diet (n = 14) for 14 days, both iliac arteries were balloon denuded and radiated, and then rabbits were switched to 0.15% cholesterol diet. After 4 weeks, BF (n = 8), BMF (n = 8), and BMS (n = 8) were deployed in denuded and radiated areas. Four weeks later animals were euthanized, arterial segments were processed for morphometry. The neointimal area in vessels implanted with BF stents was significantly less than that seen in vessels implanted with BMS (0.90 mm(2) ± 0.14 vs. 1.29 mm(2) ± 0.23, P <0.01). Percent fibrin and fibrin score were higher with BMF stents compared to BMS (P <0.03 and <0.04) and giant cell number was significantly higher with both BMF and BF stents (P < 0.01 for both). Percent endothelialization was significantly higher and % uncovered struts were lower with BMS compared to either BMF or BF stents (P < 0.05 for both). This study demonstrates that compared to BMS, BF stents significantly decreased neointimal hyperplasia.