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n¼20), and 42 mo. (n¼21) by light microscopy or scanning electron microscopy (SEM) (110 BVS and 71 XV). In addition, pharmacokinetics and gel permeation chromatography (GPC) analysis were performed at various time points. Results: Vascular responses to BVS and XV were largely comparable at all time points, with struts being sequestered in neointima. SEM confirmed rapid endothelial coverage by 1 mo. in both BVS and XV implanted arteries. Inflammation was minimal to mild for both devices, though from 12 to 36 mo. mean scores were greater for BVS. Pharmacokinetics revealed a similar drug release profiles for BVS and XV. Consistent with drug elution, fibrin deposition was similar between BVS and XV at 1 mo. and rapidly decreased or was absent beyond 3 mo. Histomorphometry showed positive remodeling in BVS-implanted arteries that started beyond 12 mo. Similarly, histomorphologic changes of BVS dismantling were observed beyond 12 mo., and by 36 mo., resorption sites (pre-existing struts) of BVS were poorly discernible from the surrounding neointima. GPC analysis confirmed that degradation of BVS could be considered complete by 36 mo. Additional histochemical staining demonstrated infiltration of proteoglycans and collagen between acellular homogenous hyaline material in resorption sites of BVS beginning beyond 12 mo. with resorption sites being near completely composed of connective tissue by 42 mo. Conclusions: BVS demonstrates comparable safety to XV in porcine coronary arteries with positive remodeling, minimal inflammation, and near complete degradation at 36 mo.

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