Abstract 2222: Angioscopic Findings of Neointimal Coverage over Sirolimus-Eluting Stents: One Year Follow-up Study
Background: The sirolimus-eluting stent (SES) is effective in reducing instent restenosis (ISR) beyond one year. However, neointima following SES implantation beyond one year has not been well understood.
Method: We evaluated the neointima 11 ± 1 months after SES implantation using angioscopy (Vecmover, Clinical Supply), and compared the findings with those implanted with bare-metal stents (BMS). Angioscopy was performed in 26 patients (age 66 ± 8 years, male gender 85%) with 41 stents (15 SES and 26 BMS). Neointimal coverage 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 by angioscopy. Presence of thrombi was also assessed.
Results: Ninety-two % of BMS showed Grade 3, whereas only 13% of SES did. Sixty % of SES showed grade 1. Strikingly, complete absence of neointimal coverage was observed in a SES as long as 291 days after implantation. Four red thrombi and 2 white thrombi were detected, which were equally distributed in BMS and SES. In the entire cohort of angioscopic 41 observations, thrombi were significantly associated with grade 0 –2 coverage (p = 0.004).
Conclusions: At one year follow-up, SES still shows low grade neointimal coverage, which was strikingly different from BMS. Because low grade neointimal coverage related to thrombi, prolonged dual anti-platelet therapy may be preferred in DES implanted patients.