Angioscopic characteristics of neoatherosclerosis in coronary dug-eluting stents: comparison between the first and second generations

Very late stent thrombosis (VLST) has been the most serious issue in the era of drug-eluting stent (DES), especially for its first generation such as sirolimus-eluting stent (SES). Recently VLST has been attributed to not only incomplete endothelial coverage (EC) but also in-stent neoatherosclerosis that develops at late phase after the coronary stenting. This study aimed to characterize in-stent appearance in patients with previous stenting, using coronary angioscopy. Enrolled were 90 stented segments in 50 patients with stable angina (19 bare metal stents, BMS; 36 SES; 25 Endeavor zotarolimus-eluting stents, ZES; and 10 Xience V everolimus-eluting stents, EES). Although coronary angiography did not show any in-stent restenosis at 2.4±1.8years after the stenting, coronary angioscopy revealed the in-stent appearance, that is, presence of yellow plaques (YP) and grades of EC (e.g. no coverage, score 0; full coverage, score 3). Dual anti-platelet therapy, 100mg aspirin plus 75mg clopidogrel once daily, had been continued since the coronary intervention. In BMS, SES, ZES, and EES groups, rates of YP were 11, 25, 20, and 0%, respectively. EC grades were 2.79±0.54, 1.31±0.71, 2.24±0.83, and 1.40±0.70, respectively. To summarize, the SES group was characterized by the less of EC grade and the more incidence of YP, suggesting incomplete EC and lipid-rich neoatherosclerosis. In conclusion, these angioscopic characteristics of SES might explain the higher rate of VLST than those for BMS and the second generation of DES.