Long-Term Safety of an Everolimus-Eluting Bioresorbable Vascular Scaffold and the Cobalt-Chromium XIENCE V Stent in a Porcine Coronary Artery Model

Background—The Absorb everolimus-eluting bioresorbable vascular scaffold (Absorb) has shown promising clinical results; however, only limited preclinical data have been published. We sought to investigate detailed pathological responses to the Absorb versus XIENCE V (XV) in a porcine coronary model with duration of implant extending from 1 to 42 months. Methods and Results—A total of 335 devices (263 Absorb and 72 XV) were implanted in 2 or 3 main coronary arteries of 136 nonatherosclerotic swine and examined by light microscopy, scanning electron microscopy, pharmacokinetics, and gel permeation chromatography analyses at various time points. Vascular responses to Absorb and XV were largely comparable at all time points, with struts being sequestered within the neointima. Inflammation was mild to moderate (with absence of inflammation at 1 month) for both devices, although the scores were greater in Absorb at 6 to 36 months. Percent area stenosis was significantly greater in Absorb than XV at all time poi...