Abstract 2778: Incomplete Neointimal Coverage Two Years after Sirolimus-Eluting Stent Implantation: A Serial Angioscopic Follow-up Study
Background- The time course of neointimal formation following sirolimus-eluting stent (SES) implantation has not been extensively studied by angioscopy.
Methods- Serial angioscopic findings at 1st (3.6 ± 1.1 months), 2nd (10.5 ± 1.6 months), and 3rd (21.2 ± 2.2 months) follow-ups following stent implantation were compared between SES (n = 17) and bare-metal stents (BMS, n = 11). Neointimal coverage, existence of thrombus and yellow plaques underneath the stents were assessed. Neointimal coverage over the stent was graded as: grade 0 = struts were exposed similarly to the time of implantation; grade 1 = struts were covered, but not embedded; grade 2 = struts were embedded by the neointima; grade 3 = struts were fully embedded and invisible.
Results- Neointimal coverage grades were significantly different between SES and BMS at any point of follow-ups (P < 0.001, Figure⇓). Serial changes were not significant in the BMS group, but the coverage grade slightly increased at the third follow up in the SES group (P< 0.05). Thrombi were detected in 4 SES. Yellow plaques had disappeared by the 2nd follow-up in the BMS group, whereas they were exposed in 71% of SES until the 3rd follow-up. Neointimal coverage grades correlated with thrombi (P=0.002) and yellow plaques (P<0.0001).
Conclusions- Neointimal formation was not completed at least up to 2 years following SES, associated with thrombi and yellow plaques. Theses findings suggest the need for long-term dual-antiplatelet therapy after SES implantation.