P2Y₁₂ Inhibitor Monotherapy or Dual Antiplatelet Therapy After Complex Percutaneous Coronary Interventions

Background: It remains unclear whether P2Y₁₂ inhibitor monotherapy preserves ischemic protection while limiting bleeding risk compared with dual antiplatelet therapy (DAPT) after complex percutaneous coronary intervention (PCI). Objectives: We sought to assess the effects of P2Y₁₂ inhibitor monotherapy after 1-month to 3-month DAPT vs standard DAPT in relation to PCI complexity. Methods: We pooled patient-level data from randomized controlled trials comparing P2Y₁₂ inhibitor monotherapy and standard DAPT on centrally adjudicated outcomes after coronary revascularization. Complex PCI was defined as any of 6 criteria: 3 vessels treated, ≥3 stents implanted, ≥3 lesions treated, bifurcation with 2 stents implanted, total stent length >60 mm, or chronic total occlusion. The primary efficacy endpoint was all-cause mortality, myocardial infarction, and stroke. The key safety endpoint was Bleeding Academic Research Consortium (BARC) 3 or 5 bleeding. Results: Of 22,941 patients undergoing PCI from 5 trials, 4,685 (20.4%) with complex PCI had higher rates of ischemic events. The primary efficacy endpoint was similar between P2Y₁₂ inhibitor monotherapy and DAPT among patients with complex PCI (HR: 0.87; 95% CI: 0.64-1.19) and noncomplex PCI (HR: 0.91; 95% CI: 0.76-1.09; P_interaction = 0.770). The treatment effect was consistent across all the components of the complex PCI definition. Compared with DAPT, P2Y₁₂ inhibitor monotherapy consistently reduced BARC 3 or 5 bleeding in complex PCI (HR: 0.51; 95% CI: 0.31-0.84) and noncomplex PCI patients (HR: 0.49; 95% CI: 0.37-0.64; P_interaction = 0.920). Conclusions: P2Y₁₂ inhibitor monotherapy after 1-month to 3-month DAPT was associated with similar rates of fatal and ischemic events and lower risk of major bleeding compared with standard DAPT, irrespective of PCI complexity.