Predictors of strut coverage of drug eluting stent implantation in diabetic patients

Background: Incomplete re-endothelialization of drug eluting stent (DES) segments has been associated with the occurrence of major adverse cardiac events after DES implantation. It is unknown whether on-clopidogrel platelet reactivity (OPR) and/or circulating endothelial progenitor cells (EPC) levels may predict uncovered strut rate in diabetic patients treated by DES implantation. Methods: One-hundred and five diabetic patients undergoing elective DES implantation were included into the study. EPC levels and OPR were assessed at 24 h (baseline) and 3 months. EPC were evaluated by flow cytometric analysis and defined by the co-expression of the markers CD34 and KDR. OPR was assessed using the impedance aggregometer. The degree of DES re-endothelialization was assessed at 3 months by optical coherence tomography. Results: A direct correlation was observed between the uncovered strut rate and OPR both at baseline (r = 0.47: p < 0.001) and at the 3 months (r = 0.25: p = 0.015). On the contrary, we found no significant correlation between EPC level and uncovered strut rate either at baseline (r = -0.02; p = 0.85) or at 3 months (r = -0.06; p = 0.13). By multivariable regression analysis, independent predictors of uncovered strut rate > 5% were complex lesions (OR = 5.35; 95% confidence interval 1.32-17.57; p = 0.027) and OPR at baseline (OR = 4.73; 95% confidence interval 1.04-8.14; p = 0.039). Conclusions: In diabetic patients treated with DES implantation OPR at baseline and complex lesions are independent predictors of uncovered strut rate at 3 months.