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

- Substudy of IN-PACT CORO trial comparing, by adoption of optical coherence tomography, the amount of neointimal growth and stent struts coverage at six months of follow up, in elective patients randomised to conventional PCI with bare metal stent implantation (BMS group) or to stent implantation with pre or postdilation with a drug coated balloon (BMS + DCB group)
- Lower neointimal regrowth observed in BMS + DCB group
- First in vivo demonstration that higher neointimal volume and a lower rate of uncovered struts at six months of follow up are significantly associated to higher baseline levels of endothelial progenitor cells (EPC)
- Baseline EPC level is an independent predictor of neointimal volume and struts coverage rate at six months of follow up.
- At the same, the detection of higher neointimal volume in those patients with persistent high EPC levels at follow up suggests the possible involvement of these elements in an exaggerated healing answer to stent-related injury leading to instent restenosis.

BackgroundEndothelialisation 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).MethodsPatients undergoing elective PCI to native vessels and randomised to bare metal stent (BMS) alone versus BMS plus drug coated balloon (DCB) were included. At six months, angiographic follow-up and FD-OCT were 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.ResultsTwenty 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 (β: 0.55; p < 0.001 and β: − 0.51; p: 0.001, respectively), while only EPC levels were independently associated to %US (β: − 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.ConclusionOur 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.