Abstract
OBJECTIVE: This study aimed to evaluate the comparative effectiveness and safety of clopidogrel versus aspirin as monotherapy following adequate dual antiplatelet therapy (DAPT) in patients with acute coronary syndrome (ACS). METHODS: MEDLINE, Embase, and CENTRAL were searched from database inception to September 1, 2023. Randomized controlled trials (RCTs) and observational studies evaluating the effectiveness or safety of clopidogrel versus aspirin as monotherapy following DAPT in patients with ACS who received a drug-eluting stent were included. Random-effects meta-analyses were conducted to compare risks of major adverse cardiovascular events (MACE) and clinically relevant bleeding. RESULTS: Of 6242 abstracts identified, three unique studies were included: one RCT and two retrospective cohort studies. Studies included a total of 7081 post-percutaneous coronary intervention ACS patients, 4260 of whom received aspirin monotherapy and 2821 received clopidogrel monotherapy. Studies included variable proportions of patients with ST-elevation myocardial infarction (STEMI), non-STEMI, and unstable angina. From the meta-analysis, clopidogrel was associated with a 28% reduction in the risk of MACE compared with aspirin (hazard ratio [HR]: 0.72; 95% confidence interval [CI]: 0.54, 0.98), with no significant difference in clinically relevant bleeding (HR: 0.92; 95% CI: 0.68, 1.24). CONCLUSION: Despite the paucity of published evidence on the effectiveness and safety of clopidogrel versus aspirin in patients with ACS post-drug-eluting stent implantation, this meta-analysis suggests that clopidogrel versus aspirin may result in a lower risk of MACE, with a similar risk of major bleeding. The present results are hypothesis-generating and further large RCTs comparing antiplatelet monotherapy options in ACS patients are warranted.