P2Y12 Inhibitors versus Aspirin Monotherapy for Long-term Secondary Prevention of Atherosclerotic Cardiovascular Disease Events: A Systematic Review and Meta-analysis

Patients with established atherosclerotic cardiovascular disease (ASCVD) need long-term antiplatelet therapy to decrease the risk of future ASCVD events. We searched PubMed, Cochrane Library, and ClinicalTrials.gov (inception through September 2021) for randomized controlled trials (RCTs) evaluating P2Y₁₂ inhibitors vs aspirin for secondary prevention of ASCVD events. Seven RCTs including a total of 56,982 patients were included in this analysis. The median follow-up duration was 22.8 (IQR 12) months. When P2Y₁₂ inhibitors were compared with aspirin as long-term antiplatelet therapy for secondary prevention of ASCVD events, there was a significant decrease in the risk of myocardial infarction [RR: 0.83; 95% CI: 0.72-0.94], and stroke [RR: 0.90; 95% CI: 0.83-0.99]. However, there was no significant difference in all-cause mortality [RR: 1.02; 95% CI: 0.92-1.12], or cardiovascular mortality [RR: 0.95; 95% CI: 0.83-1.08] between P2Y₁₂ inhibitors and aspirin users. Additionally, there was no significant difference in major bleeding events [RR: 0.88; 95% CI: 0.74-1.04], or all bleeding events [RR: 1.09; 95% CI: 0.90-1.33] between P2Y₁₂ inhibitors and aspirin groups. Use of P2Y₁₂ inhibitor monotherapy is associated with lower rates of myocardial infarction and stroke in ASCVD patients without any significant difference in mortality, or bleeding compared to aspirin monotherapy.