232: Mobilization of CD34+KDR+ cells among circulating progenitors predicts target lesion revascularization

Endothelial lesion and regeneration are critical events in the process leading to in-stent restenosis (ISR) after bare metal stent percutaneous coronary intervention (PCI).ObjectivesWe prospectively investigated the relationship between markers reflecting the endothelial response to injury and the occurrence of ISR in patients undergoing PCI.Method and resultsWe performed a multicentre prospective study which included 156 patients undergoing elective PCI with bare-metal stent (BMS). The endothelial lesion was assessed by the enumeration of circulating endothelial cells (CEC). Endothelial regeneration was evaluated by enumeration of circulating CD34+ progenitors cells (PC) and CD34+KDR+ endothelial progenitor cells (EPC). Measurements were performed before PCI (H0), 6 and 24 hours (H6 and H24) after. Dynamic changes were evaluated by calculating delta value (delta) of each marker. The primary and secondary end-points of the study were clinical target lesion revascularizations (TLR) and major adverse cardiovascular events (MACE) at 6 months follow-up. During follow-up, 28 MACE were recorded including 27 TLR. PCI induced a significant rise in CEC, CD34+ PC and CD34+KDR+. Baseline, H6 and H24 levels of markers did not differ between patients with and without TLR. The delta percentage of CD34+ PC expressing KDR was significantly reduced in patients with TLR compared to patients without TLR (-0.56±8.1 vs 2,91±6,2; p=0.015). In multivariate analysis, this parameter independently predicted the occurrence of TLR and MACE (p=0.02 and p=0.014 respectively).ConclusionIn response to PCI, rather than the extent of the endothelial injury, the proportion of CD34+KDR+ mobilized among PC determines the risk of TLR and MACE