The effect of sirolimus-eluting stent implantation on re-endothelialization: a comparative study with bare-metal stent implantation in rabbits

Objective: To evaluate the effect of sirolimus-eluting stent implantation on the reendothelialization of abdominal aorta in rabbits, and to compare it with that of bare-metal stent implantation. Methods: Twenty-four New Zealand male rabbits were randomly and equally divided into two groups after hyperlipemia feeding. Sirolimus-eluting stent, Firebird, or bare-metal stent, Mustang, was implanted in the abdominal aorta in two groups. Every three experimental rabbits from both groups were sacrificed each time at 3, 7, 14 and 28 days after the procedure, and the specimens of aorta were harvested and processed for observing the vascular endothelia with scanning electron microscopy, and the degree of re-endothelialization was analyzed by computed imaging analysis technique. Results: Three days after the procedure, in both groups neogenetic endothelia could be hardly seen in the treated aorta although inflammatory reaction was rather obvious. At the time of 7, 14 and 28 days after the operation, the covering rate of re-endothelialization in sirolimus-eluting stent group was significantly lower than that in bare-metal stent group (15% ±8% vs 53% ± 9%, 49% ±16% vs 83% ± 4% and 73% ± 3% vs 93% ± 4% respectively, P < 0.05). Conclusion: Compared with bare-metal stent, sirolimus-eluting stent will markedly delay the re-endothelialization of the implanted vessels. (authors)