Background: No previous study has reported a comprehensive comparison of the chronic angioscopic findings after bare metal stent (BMS), and 1st- and 2nd-generation drug-eluting stents (DES).
Methods and results: The Multicenter Study on Intra-Coronary Angioscopy after Stent (MICASA) is a multicenter registry of coronary angioscopy. A total of 264 stents were observed by coronary angioscopy 1 year after PCI. There were 15 BMS, 90 1st-generation DES, and 159 2nd-generation DES. Neointimal coverage (NC) of the stent was classified into 4 grades from 0 (no coverage) to 3 (complete coverage). Yellow color (YC) of plaque at the stented segment was graded from 0 (white) to 3 (bright yellow). Minimum (Min-) and Maximum (Max-) NC grade were significantly lower with 1st- and 2nd-generation DES than with BMS. Although the Max-NC grade was similar, the Min-NC grade was significantly higher for 2nd-generation DES than for 1st-generation DES. Both the YC grade and the incidence of thrombus with 2nd-generation DES were lower than with the 1st-generation DES and were comparable to BMS. Multivariate analysis showed that low-density lipoprotein, 1st-generation DES, and acute coronary syndrome were independent factors for yellow plaque (YG2 or 3), and that hypertension and 1st-generation DES were independent factors for the incidence of thrombus.
Conclusions: Coronary angioscopy revealed more homogeneous coverage with white neointima and less thrombus after 2nd-generation DES as compared with 1st-generation DES. These findings may explain the favorable clinical outcomes observed for patients treated with 2nd-generation DES. (Circ J 2016; 80: 1916-1921).