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.