[Stent thrombosis in the era of drug-eluting stents]

Coronary stent thrombosis is frequently associated with death or myocardial infarction (MI). New definitions according to the Academic Research Consortium (ARC) were proposed to serve as standard criteria for stent thrombosis. According to these definitions, stent thrombosis was classified as acute (within 24 h post implantation), subacute (1-30 days), late (31 days to 1 year), and very late (later than 1 year). Furthermore, stent thrombosis was differentiated in definite with angiographic or autoptic verification, probable, and possible. In meta-analyses using the ARC criteria, the occurrence of subacute stent thrombosis did not differ between drug-eluting stents (DES; Cypher, Taxus) or bare-metal stents (BMS) with < 1%. Very late stent thrombosis occurred 0.4-0.6% more frequently with DES compared to BMS. Available follow-up periods are limited to 4 years. The occurrence of death and MI did not differ between DES and BMS within the total follow-up period. In the meta-analysis of the Taxus studies, the event rates (death and MI) were initially lower with DES compared to BMS based on the reduced need for target vessel revascularization. Nevertheless, this was compensated in the following period by a higher event rate due to very late stent thrombosis. In real-world registries, the event rates are higher than in the first randomized studies. With DES implantation as a routine strategy, the occurrence of angiographically documented stent thrombosis was 2.9% within a period of 3 years. Classic predictors for stent thrombosis with BMS remain relevant also in the DES era. The delayed endothelialization with DES in combination with suboptimally implanted DES takes the patients to a higher and longer risk for stent thrombosis. Several guidelines recommend dual antiplatelet therapy for 12 months after DES implantation in noncomplex lesions. In complex lesions combined antiplatelet treatment should be prescribed 24 months or longer (e.g., DES after brachytherapy). Patients scheduled for surgical procedures or patients with reduced compliance should not be treated with DES.