Is there delayed restenosis in patients with coronary artery disease treated with sirolimus-eluting stent?

BACKGROUND: Although long-term follow-up after sirolimus-eluting stent implantation shows a sustained clinical benefit in several randomized and registered trials, little is known about the pattern of neointimal growth beyond the first 6 to 9 months. In this study, we therefore evaluated the possible delayed restenosis in patients with coronary artery disease treated with sirolimus-eluting stent. METHODS: A total of consecutive 333 patients with 453 lesions were enrolled in this study (among 782 consecutive patients with 1023 lesions). Lesions were subjected to follow-up by quantitative coronary angiography, and patients were divided into two groups according to the time of follow-up by quantitative coronary angiography: early group (< or =270 days, n=270 with 369 lesions) and late group (>270 days, n=63 with 84 lesions). Binary restenosis was defined as stenosis of more than 50% of the lumen diameter in the target lesion. RESULTS: Baseline clinical, demographic or angiographic characteristics were well balanced between the two groups. The in-stent restenosis rate was not significant between the early group and the late group (3.5 vs. 6.0%; P>0.05). The late loss and target lesion revascularization appeared higher in late group but there were no significant differences (0.15+/-0.38 mm vs. 0.24+/-0.44 mm; and 4.9 vs. 9.5%, P>0.05, respectively). Similarly, overall thrombosis rate was also same in both groups. In-segment restenosis was, however, higher in late group compared with that in early group (7.9 vs. 16.7%, P=0.013). CONCLUSION: In this unrestricted population, the beneficial effects of sirolimus-eluting stent implantation extend out more than 1 year in real world practice, that has been confirmed by the results of the large randomized clinical trials. The late in-segment restenosis could, however, be found, suggesting that a prolonged clinical and angiographic surveillance in this subset of patients seems to be warranted.