Aspirin vs Clopidogrel 1 Month After Acute Coronary Syndrome With High-Bleeding Risk or ST-Segment Elevation.

Background: High bleeding risk (HBR) and acute coronary syndrome (ACS) subtypes (ST-segment elevation myocardial infarction [STEMI] and non-ST-segment elevation ACS [NSTE-ACS]) might be key determinants of appropriate antiplatelet strategies.

Objectives: The aim of this study was to investigate the effects of aspirin versus clopidogrel within 1 year after percutaneous coronary intervention in patients with ACS, on the basis of HBR or non-HBR and STEMI or NSTE-ACS.

Methods: Patients with ACS in the STOPDAPT-3 (Short and Optimal Duration of Dual Antiplatelet Therapy-3) trial were included. Aspirin and clopidogrel monotherapy were compared beyond 30 days and up to 1 year in the prespecified subgroups stratified by HBR or non-HBR and STEMI or NSTE-ACS. The coprimary cardiovascular endpoint was a composite of cardiovascular death, myocardial infarction, definite stent thrombosis, or ischemic stroke; the coprimary bleeding endpoint was major bleeding (Bleeding Academic Research Consortium type 3 or 5).

Results: Among 4,353 patients, 1,711 had HBR and 2,457 had STEMI. Throughout the 335-day follow-up period, the crude HRs for aspirin compared with clopidogrel were not statistically significant for cardiovascular endpoints in both the HBR or non-HBR (HRs: 0.89 [95% CI: 0.61-1.30] and 1.08 [95% CI: 0.61-1.90]; P for interaction = 0.59) and STEMI or NSTE-ACS (HRs: 1.01 [95% CI: 0.68-1.50] and 0.81 [95% CI: 0.48-1.37]; P for interaction = 0.51) subgroups. Similarly, the HRs for bleeding endpoints were not significant in both the HBR or non-HBR (HRs: 0.73 [95% CI: 0.40-1.33] and 0.71 [95% CI: 0.23-2.24]; P for interaction = 0.97) and STEMI or NSTE-ACS (HRs: 0.96 [95% CI: 0.46-2.01] and 0.53 [95% CI: 0.24-1.17]; P for interaction = 0.28) subgroups.

Conclusions: In patients with ACS, aspirin and clopidogrel demonstrated comparable effects on both cardiovascular and bleeding outcomes beyond 1 month and up to 1 year after percutaneous coronary intervention, irrespective of HBR or non-HBR and STEMI or NSTE-ACS. (Short and Optimal Duration of Dual Antiplatelet Therapy-3 Study [STOPDAPT-3]; NCT04609111).