Pathological Evaluation of Predictors for Delayed Endothelial Coverage After Currently Available Drug-eluting Stent Implantation in Coronary Arteries: Impact of Lesions With Acute and Chronic Coronary Syndromes.

BACKGROUND: The optimal duration of dual antiplatelet therapy after currently available drug-eluting stent (DES) implantation to prevent stent thrombosis (ST) remains controversial. Delayed healing is frequently identified as a leading cause of ST in the early phase. However, a thorough pathological investigation into strut coverage after currently available DES implantation is lacking-a gap addressed in the current study. METHODS: From our autopsy registry of 199 stented lesions, 4,713 struts from 66 currently available DES-stented lesions with an implant duration ≤370 days were histologically evaluated. Endothelial coverage was defined as the presence of luminal endothelial cells overlying struts and an underlying smooth muscle cell layer. The stented lesions were classified into acute coronary syndrome (ACS) (n = 40) and chronic coronary syndrome (CCS) (n = 26) groups and were compared. Endothelial coverage predictors were identified through logistic analysis. RESULTS: Although ACS and CCS lesions presented comparable clinical characteristics, including age, sex, and cause of death, the latter exhibited a significantly higher prevalence of chronic kidney disease and hemodialysis than the former (33.3% vs. 65.2%; p = 0.02, 7.7% vs. 30.4%; p = 0.02). The poststent implant median duration was significantly shorter in ACS lesions than in CCS lesions (13 [IQR 5-26 days] vs. 40 [IQR 16-233 days]; p < 0.01). The endothelial coverage percentage was 3.5% at 30 days and 27.7% at 90 days after currently available DES implantation. Multivariable logistic regression analysis implicated implant duration of ≤90 days [odds ratio (OR), 0.009; 95% confidence interval (CI), 0.006-0.012; p < 0.01], superficial calcification (OR, 0.11; 95% CI, 0.07-0.17; p < 0.01), ACS culprit site (OR, 0.29; 95% CI, 0.09-0.94; p = 0.039), and circumferentially durable polymer-coated DES (OR, 0.32; 95% CI, 0.24-0.41; p < 0.01) as delayed endothelial coverage predictors. CONCLUSIONS: Endothelial coverage was limited at 90 days after currently available DES implantation, and the ACS culprit site and circumferentially durable polymer-coated DES were identified as independent predictors of delayed endothelial coverage. Our findings suggest the importance of underlying plaque morphology and stent technology for vessel healing after such implantation.