VASCULAR BIOLOGY Original Studies 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

Objectives: 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. Methods: Rabbits were fed with 1% cholesterol diet (n 5 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 5 8), BMF (n 5 8), and BMS (n 5 8) were deployed in denuded and radiated areas. Four weeks later animals were euthanized, arterial segments were processed for morphometry. Results: The neointimal area in vessels implanted with BF stents was significantly less than that seen in vessels implanted with BMS (0.90 mm 6 0.14 vs. 1.29 mm 6 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). Conclusion: This study demonstrates that compared to BMS, BF stents significantly decreased neointimal hyperplasia. VC 2011 Wiley Periodicals, Inc.