Long-term single antiplatelet therapy for patients with acute coronary syndrome at high-risk for ischemia and bleeding: a precision cohort study

Background To compare the prognostic effects of different single antiplatelet therapy (SAPT) regimens (aspirin vs. clopidogrel) in patients with acute coronary syndrome (ACS) at high-risk for ischemia and bleeding following percutaneous coronary intervention (PCI) and switching from 12 months of dual antiplatelet therapy (DAPT) to SAPT. Methods This study retrospectively analyzed 642 patients with ACS at high-risk of ischemia and bleeding who underwent PCI at a single-center between January 2017 and November 2022. After transitioning to SAPT, the cohort was divided into two groups based on the prescribed therapy: aspirin ( n = 435) and clopidogrel ( n = 207) groups. Patients were followed up for 24 months post-PCI. The primary endpoint was the occurrence of net adverse clinical events (NACE), including MACCE and major thrombolysis in myocardial infarction (TIMI) hemorrhage. Results The incidence of NACE was comparable between the two patient groups. However, the clopidogrel group had a lower incidence of MACCE (4.3% vs. 9.2%, P = 0.031) and TVR (1.4% vs. 6.4%, P = 0.006) compared to the aspirin group. Cox regression analysis revealed that the incidence of MACCE and TVR in the clopidogrel group were 0.458 times [ hazard ratio [HR] : 0.458; 95% confidence interval [CI]: 0.222–0.944; P = 0.034] and 0.220 times ( HR: 0.220; 95% CI: 0.067–0.724; P = 0.013) that of the aspirin group, respectively. Conclusion In patients with ACS at high-risk, transitioning to clopidogrel as SAPT after 12 months of DAPT and successful PCI was associated with a reduced incidence of MACCE and TVR compared to aspirin, without an increased risk of major bleeding events.