The recent American Heart Association/American College of Cardiology guidelines on duration of dual antiplatelet therapy (DAPT) recommend DAPT for 1 year in patients presenting with an acute coronary syndrome, with a Class IIb recommendation for continuation. We aim to assess the evidence for these recommendations using a meta-analytic approach.

We searched electronic databases for randomized trials comparing short-term (≤6 months) vs 12-month vs extended (>12 months) DAPT in patients with an acute coronary syndrome undergoing percutaneous coronary intervention. We evaluated all-cause mortality, cardiovascular mortality, myocardial infarction, stent thrombosis, and major bleeding. A random-effects model was used to calculate pooled relative risk (RR) and 95% confidence intervals (CI).

We included 8 trials comprising 12,917 patients with an acute coronary syndrome; 5 trials compared short-term vs 12-month/extended DAPT, whereas 3 trials compared 12-month vs extended DAPT. There was no significant difference in cardiovascular mortality (RR 1.04; 95% CI, 0.67-1.60), myocardial infarction (RR 1.08; 95% CI, 0.79-1.47), or major bleeding (RR 0.91; 95% CI, 0.49-1.69) between short-term and 12-month/extended DAPT. However, compared with extended DAPT, 12-month DAPT showed significantly higher risk of myocardial infarction (RR 2.00; 95% CI, 1.47-2.73), but reduced risk of major bleeding (RR 0.58; 95% CI, 0.34-0.98). All-cause mortality was found to be similar between 12-month and extended DAPT.

In acute coronary syndrome, short-term DAPT may be reasonable for some patients, whereas extended DAPT may be appropriate in select others. An individualized approach is needed, taking into account the competing risks of bleeding and ischemic events.