The effects of bare metal versus drug-eluting stent implantation on circulating endothelial cells following percutaneous coronary intervention*

BACKGROUND The purpose of this study was to compare the effects of bare metal stents (BMS) and drug-eluting stents (DES) implantation on circulating endothelial cells (CECs) which have been proposed as cellular markers of endothelial dysfunction following percutaneous coronary intervention (PCI). Recently, it has been established that DES further reduce restenosis and revascularization rate compared to bare metal stents in elective procedures. However, its benefits are compromised by the stent-related thrombosis events. METHODS 22 patients who were candidate of PCI were included in this study. The patients underwent DES implantation (n = 11) or BMS implantation (n = 11). In all patients the numbers of CECs were determined before and a week after stent implantation using flow cytometry and the obtained data were compared within and between groups by paired and unpaired Student's t-test, respectively. CECs were defined as cells negative for CD45 (FITC) and highly double positive for CD146 (PE) and CD34 (PE-Cy5) expression. RESULTS There were no significant differences in the baseline levels of CECs between two groups (p = 0.96). Stent implantation led to a significant increase in CECs compared with the preprocedural levels in the BMS group (p = 0.005) whereas there was a significant decrease in CEC numbers in DES group (p < 0.001). One week after stent implantation CECs count in BMS group was significantly higher compared to DES group (p < 0.001). CONCLUSIONS The results indicate that patients undergoing DES implantation were subjected to less endothelial injury than patients receiving BMS as indicated by CEC enumeration.