Endothelial progenitor cell capture stents: will this technology find its niche in contemporary practice?

Drug-eluting stents (DES) have significantly reduced rates of restenosis; however, elution from their surface of cytotoxic and cytostatic drugs, together with the presence of non-erodable polymers, is associated with impaired endothelialization, allergic reactions, inflammation, and vascular dysfunction, factors which have all been implicated in the most prominent safety concern with DES today —stent thrombosis (ST).1–3 The development of newer DES with polymers that are either more biocompatible, biodegradable, or completely absent, together with completely biodegradable stents has been an important step forward to minimize the potential risk of ST. Despite this, however, the rapid restoration of a functional endothelium appears, in theory at least, to be one of the most intuitive ways of minimizing the risk of ST and excessive neointimal proliferation.4 Therefore, it comes as no surprise that soon after the discovery of endothelial progenitor cells (EPCs),5 a novel coronary stent, the Genous™ EPC capture stent (OrbusNeich, Florida, USA), was developed which had a proprietary coating that contained anti-human CD34 antibodies ( Figure 1 ). These antibodies were able to capture circulating EPCs, such that the EPC capture stent was considered a potential solution to many of the problems of coronary stenting. Figure 1 Schematic diagram illustrating the underlying principal behind the EPC capture stent. The CD-34 antigen on the EPC binds to the anti CD-34 antibody on the stent's surface to promote rapid endothelialisation. Six years on, and Beijk et al. 6 report the 1-year outcomes of the TRIAS HR study, the first randomized study comparing the Genous™ EPC stent with a conventional DES (the Taxus Liberte stent). This study adds to the paucity of data already available on the EPC stent, and disappointingly reaffirms the disparity between technological promise and real-life clinical results. Prior to the completion of 1-year follow-up this single-centre study was transformed into … *Corresponding author. Tel: +31 10 7035260, Fax: +31 10 4369154, Email: p.w.j.c.serruys{at}erasmusmc.nl