Dual antiplatelet therapy beyond 12 months versus for 12 months after drug-eluting stents for acute myocardial infarction

Background: The optimal duration of dual antiplatelet therapy (DAPT) after acute coronary syndrome remains uncertain. This study investigated the benefit of DAPT beyond 12 months after drug-eluting stents (DES) for acute myocardial infarction (MI). Methods: From Korea Acute Myocardial Infarction Registry-National Institute of Health database, 6199 patients treated with DAPT for 12 months after DES (second-generation DES 98%) without ischemic or bleeding events were analyzed. The primary endpoint was major adverse cardiovascular and cerebrovascular events (MACCE), a composite of death from any cause, MI, or ischemic stroke during the period from 12 to 24 months. Results: After adjustment using inverse probability of treatment weighting, patients who received DAPT beyond 12 months (n = 4795), compared to patients treated with 12-month DAPT (n = 1404), had a similar incidence of MACCE (1.3% vs. 1.0%, HR: 1.32, 95% CI: 0.71–2.45, p = 0.378). The 2 groups did not differ significantly in the rates of death (0.1% vs. 0.1%), MI (0.8% vs.0.6%), stent thrombosis (0.1% vs. 0.2%), ischemic stroke (0.4% vs. 0.2%), and major bleeding (0.1% vs. 0.1%). The rate of net adverse clinical events was 1.4% with DAPT beyond 12 months and 1.1% with 12-month DAPT (p = 0.466). Conclusions: DAPT beyond 12 months, as compared with 12-month DAPT, in real-world patients with acute MI treated predominantly with second-generation DES did not reduce the risk of MACCE. The rates of major bleeding and net adverse clinical events did not differ significantly between the 2 treatments.