Sex-Based Outcomes of P2Y12 Inhibitor Monotherapy After Three Months of Dual Antiplatelet Therapy in Patients Undergoing Percutaneous Coronary Intervention

Background: In patients undergoing percutaneous coronary intervention (PCI) in the SMART-CHOICE trial, P2Y12 inhibitor monotherapy after three months of dual antiplatelet therapy (DAPT) achieved clinical outcomes comparable to those of 12 months of DAPT. Nonetheless, the effects of sex on these outcomes remain unknown. Methods: This open-label, non-inferiority, randomized study, conducted in 33 hospitals in South Korea, included 2,993 patients undergoing PCI with drug-eluting stents. Patients were randomly assigned to receive DAPT (aspirin plus a P2Y12 inhibitor) for three months then P2Y12 inhibitor alone for nine months, or DAPT for the entire 12 months. The primary endpoints were major adverse cardiac and cerebrovascular events (a composite of all-cause death, myocardial infarction, or stroke) 12 months after the index procedure. The bleeding endpoints were Bleeding Academic Research Consortium (BARC) bleeding types 2 to 5. Results: Of the patients, 795 (26.6%) were women, who were older and had a higher prevalence of hypertension, diabetes, and dyslipidemia than men. The sexes exhibited comparable primary endpoints (adjusted hazard ratio [HR], 0.93; 95% confidence interval [CI], 0.55-1.55; P= 0.770) and bleeding endpoints (adjusted HR, 1.07; 95% CI, 0.63-1.81; P= 0.811). P2Y12 inhibitor monotherapy vs DAPT was associated with lower risk of BARC type 2 to 5 bleeding in women (adjusted HR, 0.40; 95% CI, 0.16-0.98; P= 0.045) but the difference was not statistically significant when using the Bonferroni correction. The primary endpoints were similar between treatment groups in both sexes. Conclusion: In both sexes undergoing PCI, P2Y12 inhibitor monotherapy after three months of DAPT achieved similar risks of the primary endpoints and the bleeding events compared with prolonged DAPT. Therefore, the benefits of early aspirin withdrawal with ongoing P2Y12 inhibitors may be comparable in women and men. Trial Registration: ClinicalTrials.gov Identifier: NCT02079194