Background-The influences of antiplatelet therapy discontinuation on the risk of stent thrombosis and long-term clinical outcomes after drug-eluting stent implantation have not yet been addressed adequately. Methods and Results-In an observational study in Japan, 2-year outcomes were assessed in 10 778 patients undergoing sirolimus-eluting stent implantation. Data on status of antiplatelet therapy during follow-up were collected prospectively. Incidences of definite stent thrombosis were 0.34% at 30 days, 0.54% at 1 year, and 0.77% at 2 years. Thienopyridine use was maintained in 97%, 62%, and 50% of patients at 30 days, 1 year, and 2 years, respectively. Patients who discontinued both thienopyridine and aspirin had a significantly higher rate of stent thrombosis than those who continued both in the intervals of 31 to 180 days, 181 to 365 days, and 366 to 548 days after stent implantation (1.76% versus 0.1%, PϽ0.001; 0.72% versus 0.07%, Pϭ0.02; and 2.1% versus 0.14%, Pϭ0.004, respectively). When discontinuation of aspirin was taken into account, patients who discontinued thienopyridine only did not have an excess of stent thrombosis in any of the time intervals studied. Adjusted rates of death or myocardial infarction at 24 months were 4.1% for patients taking thienopyridine and 4.1% for patients not taking thienopyridine (Pϭ0.99) in the 6-month landmark analysis. Conclusions-Discontinuation of both thienopyridine and aspirin, but not discontinuation of thienopyridine therapy only, was associated with an increased risk of stent thrombosis. Landmark analysis did not suggest an apparent clinical benefit of thienopyridine use beyond 6 months after sirolimus-eluting stent implantation. (Circulation. 2009;119:987-995.)

Background-There is a scarcity of long-term data from large-scale drug-eluting stent registries with a large enough sample to evaluate low-frequency events such as stent thrombosis (ST). Methods and Results-Five-year outcomes were evaluated in 12 812 consecutive patients undergoing sirolimus-eluting stent (SES) implantation in the j-Cypher registry. Cumulative incidence of definite ST was low (30 day, 0.3%; 1 year, 0.6%; and 5 years, 1.6%). However, late and very late ST continued to occur without attenuation up to 5 years after sirolimus-eluting stent implantation (0.26%/y). Cumulative incidence of target lesion revascularization within the first year was low (7.3%). However, late target lesion revascularization beyond 1 year also continued to occur without attenuation up to 5 years (2.2%/y). Independent risk factors of ST were completely different according to the timing of ST onset, suggesting the presence of different pathophysiological mechanisms of ST according to the timing of ST onset: acute coronary syndrome and target of proximal left anterior descending coronary artery for early ST; side-branch stenting, diabetes mellitus, and end-stage renal disease with or without hemodialysis for late ST; and current smoking and total stent length Ͼ28 mm for very late ST. Independent risk factors of late target lesion revascularization beyond 1 year were generally similar to those risk factors identified for early target lesion revascularization. Conclusion-Late adverse events such as very late ST and late target lesion revascularization are continuous hazards, lasting at least up to 5 years after implantation of the first-generation drug-eluting stents (sirolimus-eluting stents), which should be the targets for developing improved coronary stents. (Circulation. 2012;125:584-591.)Key Words: coronary artery disease Ⅲ prognosis Ⅲ restenosis Ⅲ stents Ⅲ thrombosis C oronary drug-eluting stents (DES) have been used widely in clinical practice. Results from several randomized, controlled trials and registries comparing midterm (2-3 years) outcome between bare metal stents (BMS) and DES are generally reassuring for DES use with a marked reduction of target lesion revascularization (TLR) without major safety issues. 1,2 However, in contrast to the clinical course after BMS implantation, 3 late adverse events such as very late stent thrombosis (VLST) and late TLR are reported to continue occurring beyond 1 year up to 3 to 4 years after DES implantation. 4,5 Despite lingering concerns about DES-related late adverse events, there is a scarcity of longer-term data from large-scale DES registries with adequate statistical power to evaluate lowfrequency events such as stent thrombosis (ST). Editorial see p 562 Clinical Perspective on p 591In the present report, we comprehensively evaluated 5-year clinical outcome after sirolimus-eluting stent (SES) implanContinuing medical education (CME) credit is available for this article. Go to http://cme.ahajournals.org to take the quiz. Received May 31, 2011; accepted November 7, 2011 Met...