Abstract 652: Coronary Angioscopic Observation of Extremely Late Arterial Repair Catch-up after Sirolimus-eluting Stent Implantation

Abstract

Sirolimus, a bio-suppressive drug, delays coronary arterial repair after implantation of Cypher sirolimus-eluting stents (SES), a representative first generation drug-eluting stent. It remains unclear, however, whether this delayed repair would catch up with bare metal stents (BMS) along extremely long observation. The aim of this study was angioscopic comparison of coronary arterial repair through a decade after implantation of SES and BMS. Enrolled were 31 patients with previous implantation of SES (n = 22) or BMS (n = 9). Duration after stent implantation (DSI) ranged from 3 to 10.5 years in both groups. Thirty-seven SES were implanted into the SES group and 17 BMS into the BMS group. The 54 stented segments were analyzed by quantitative coronary angiography (QCA) and non-obstructive coronary angioscopy (CAS). Under continuous flush of low-molecular-weight dextran, CAS visualized in-stent appearance, i.e. endothelial stent coverage (ESC), presence of yellow plaque (YP), and in-stent mural thrombi (ISMT). ESC was semi-quantified into 4 grades (grade 0, no coverage; grade 1, thin coverage; grade 2, decent coverage; grade 3, full coverage). QCA showed in-stent restenosis neither in SES- nor BMS-implanted segments (% diameter stenosis 14.8 ± 7.9 vs. 16.2 ± 8.2, respectively). Incidence of YP was 27% in SES and 6% in BMS (P < 0.03). Incidence of ISMT was 24% in SES, whereas never in BMS. ESC grade of BMS was either grade 1 (24%) or grade 3 (76%). SES-implanted segments were divided into two groups, i.e. DSI > 8 years (n = 5) and DSI < 8 years (n = 32). In the former (10.5 > DSI > 8 years), ESC grade of SES was either grade 1 (40%) or grade 3 (60%), being similar to ESC after BMS implantation. In the latter (8 > DSI > 3 years), however, ESC grade varied from grade 0 (6%), grade 1 (63%), grade 2 (25%), and grade 3 (6%). Incidence of YP or ISMT was 60% in the former, suggesting progression of neoatherosclerosis at extremely late phase. In conclusion, from the viewpoint of ESC, coronary arterial repair at SES implantation appeared to catch up with BMS at around 8 years later, although incidence of YP or ISMT remained still greater in SES than BMS at extremely late phase.