Comparison of Neointimal Tissue Characteristics Between Bare-metal and Second-generation Drug-eluting Stents Nine Months after Implantation in Patients with ST-segment Elevation Myocardial Infarction

Background: Neointimal tissue characteristics after implantation of stents are related to late/ very late stent thrombosis and/ or restenosis of target lesion. However, the difference of them has not been fully elucidated among bare-metal stents (BMS) and second-generation drug-eluting stents (DES). Methods: The present study uses optical coherence tomography (OCT) to compare neointimal tissue characteristics among BMS (n = 22), Endeavor zotarolimus - (E-ZES; n = 21), everolimus - (EES; n = 22) and biolimus A9 - (BES; n = 23) eluting stents in the patients with STEMI who underwent follow-up coronary angiography at nine months after stent implantation. Results: Quantitative coronary angiography revealed significantly higher restenosis rates for BMS and E-ZES than EES and BES. OCT showed significantly lower and higher rates for covered and uncovered EES, respectively, than for BMS and E-ZES. The malapposition rate for E-ZES was significantly lower than those of other two types of DES. The neointima of EES and BES was significantly thinner than that of BMS and E-ZES. Evagination was more prevalent in BES among the four stents, and the rate of evagination/strut significantly correlated with positive remodeling (r = 0.312, p = 0.006). Conclusion: Neointimal tissue characteristics were different among BMS and second-generation DES at nine months after implantation into patients with STEMI. This might be related to the differences of future cardiac events.