Sirolimus-eluting stent implantation for bare-metal in-stent restenosis: is there any evidence for a late catch-up phenomenon?

Objectives In-stent restenosis occurs not infrequently after intracoronary implantation of bare-metal stents. Many techniques have been proposed for the treatment of in-stent restenosis, but drug-eluting stents seem to provide the best early and mid-term results. We aimed to appraise whether the effectiveness of drug-eluting stents for in-stent restenosis is maintained even in the long term. Methods Participants in this prospective multicenter study were patients with in-stent restenosis treated with sirolimus-eluting stents. The primary endpoint was freedom from major adverse cardiovascular events (i.e. death, nonfatal myocardial infarction, target vessel revascularization, or stent thrombosis) in the long term (>= 24 months), with 6-month angiography planned for all patients. Results A total of 271 consecutive patients were enrolled (332 sirolimus-eluting stents). Procedural success was obtained in all patients, with no case of in-hospital death, acute/subacute stent thrombosis, stroke, or urgent coronary bypass. Survival free from major cardiovascular events decreased progressively from 98.8% at 1 month, to 95.7,83.7, 75.4, and 65.8% at 6,12, 24, and 30 months, respectively. A similar attrition in freedom from repeat target vessel was found from 97.6% at 6 months to 76.7% at 30 months. A total of four possible and one definite stent thromboses (2.6%) were noted, all occurring several months after clopidogrel discontinuation and in patients on life-long aspirin. Conclusion The present study supports the mid-term safety and effectiveness of sirolimus-eluting stents for the treatment of in-stent restenosis in comparison with the other available treatments. Whether the late catch-up phenomenon observed in repeat target revascularization and stent thrombosis is an incidental finding deserves further rigorous scrutiny.