Prolonged Dual Antiplatelet Therapy in Acute Myocardial Infarction Patients Without Revascularization: China Acute Myocardial Infarction Registry Study

Abstract

At least 12-month dual antiplatelet therapy (DAPT) is one of the standards of care following Percutaneous Coronary Intervention (PCI) in patients with acute coronary syndrome. However, study on prolonged DAPT for acute myocardial infarction (AMI) patients without revascularization is limited. We studied 1744 AMI patients without revascularization from the China Acute Myocardial Infarction registry between January 2013 and September 2014. These patients were on DAPT and did not experience AMI, stroke, or bleeding events at 12-month follow-up. We divided them into two groups: 12-month DAPT group (DAPT for at least 12 months but less than 18 months) and 18-month DAPT group (DAPT for at least 18 months). The primary outcome is 24-month all-cause death. Overall, 1221 (70.0%) patients took DAPT for ≥12 months but <18 months, while 523 (30.0%) patients took DAPT for ≥18 months. The two groups had comparable proportions with high ischemic risk (27.0% vs. 25.6%, P = 0.5418), as well as high bleeding risk (29.0% vs. 28.5%, P = 0.8316). At 24 months, the all-cause mortality rate of 18-month DAPT group was significantly lower than that for 12-month DAPT group (3.7% vs 5.9%, P = 0.0471). Adjusted hazard ratio for all-cause death also showed statistical significance (0.59, 95% CI: 0.35-0.99, P = 0.0444). In conclusion, DAPT for at least 18 months appears to be associated with lower 24-month mortality for non-revascularization AMI patients without events within 12 months after onset.