Objectives: To study the effect of endothelial progenitor cell (EPC) capture on the vascular response to coronary stenting. Background: The introduction of drug-eluting stents has reduced the need for target lesion revascularization, but their effect on delayed healing, inflammation, and vascular dysfunction has emphasized the need to design strategies that improve current DES. One such strategy is to improve endothelialization by capturing CD34-positive cells (EPC) by the stent surface. The first human clinical trial using coronary EPC capture stents showed stent safety but neointimal thickness (NIT) was not reduced compared to bare metal stents (BMS). To understand these responses we studied the coronary response to the EPC capture stent in swine. Methods and Results: The stent, coated with murine antihuman monoclonal CD34 antibodies, was assessed with QCA guided stent implantation in normal swine coronary arteries for early endothelialization at 2 and 5 days, and NIT at 28 and 90 days in comparison to control stents carrying a non-specific murine antibody or to BMS. The main finding was that while the EPC capture stent significantly improved early endothelialization it did not reduce NIT at 28 and 90 days. Conclusions: The EPC capture stent improves early endothelialization in swine but this does not affect neointimal thickness as compared to control stents at 28 and 90 days. (C) 2011 Wiley Periodicals, Inc.