Dual role of circulating endothelial progenitor cells in stent struts endothelialisation and neointimal regrowth: A substudy of the IN-PACT CORO trial

Background: Endothelialisation is a crucial event after percutaneous coronary intervention (PCI). Endothelial progenitor cells (EPCs) are bone marrow derived elements with reparative properties. We aimed to assess the relationship between circulating EPC levels and stent neointimal hyperplasia (NIH) using frequency domain optical coherence tomography (FD-OCT). Methods: Patients undergoing elective PCI to native vessels and randomised to baremetal stent (BMS) alone versus BMS plus drug coated balloon (DCB) were included. At six months, angiographic follow-up and FD-OCTwere performed to measure percentage neointimal hyperplasia volume obstruction (% NIHV), and percentage of uncovered stent struts (% US). Venous blood samples were obtained before the procedure and at six months to detect CD34+ CD45dimKDR+ EPC levels. Results: Twenty patients were enrolled. A significant relationship was observed between baseline EPC levels and % NIHV (R: 0.63, p: 0.03) and % US (R: -0.56, p: 0.01) at follow-up. Both EPC levels and DCB use were independently related to % NIHV (beta: 0.55; p b 0.001 and beta:-0.51; p: 0.001, respectively), while only EPC levelswere independently associated to % US (beta: -0.52; p: 0.01). Higher % NIHV (p: 0.004) and lower % US (p: 0.005) were observed in patients with stable or increasing EPC level. Conclusion: Our study shows a relationship between EPC levels and stent strut coverage, supporting a dual role for these cells in favouring stent endothelialisation but also NIH growth. (C) 2014 Elsevier Inc. All rights reserved.