Long-Term Aspirin vs Clopidogrel After Coronary Stenting by Bleeding Risk and Procedural Complexity.

Importance: Antiplatelet monotherapy in the chronic maintenance period for patients with high bleeding risk (HBR) and those who have undergone complex percutaneous coronary intervention (PCI) has not yet been explored. Objective: To compare clopidogrel vs aspirin monotherapy in patients with HBR and/or PCI complexity. Design, Setting, and Participants: This post hoc analysis of the multicenter HOST-EXAM Extended study, an open-label trial conducted across 37 sites in South Korea, enrolled patients from 2014 to 2018 with up to 5.9 years of follow-up. The analysis was conducted from February to November 2023. Patients who maintained dual antiplatelet therapy (DAPT) event-free for 6 to 18 months following PCI were included. Interventions: Patients were randomized to receive either clopidogrel or aspirin in a 1:1 ratio. Those with sufficient data to assess HBR or complex PCI were analyzed. Main Outcomes and Measures: Coprimary end points were thrombotic composite end point (cardiovascular death, nonfatal myocardial infarction, stroke, readmission due to acute coronary syndrome, and definite/probable stent thrombosis) and any bleeding (Bleeding Academic Research Consortium type 2 to 5). Results: Of 3974 patients included (mean [SD] age, 63.4 [10.7] years; 2976 male [74.9%]), 866 had HBR (21.8%), and 849 underwent complex PCI (21.4%). Clopidogrel as compared with aspirin was associated with lower rates of thrombotic and bleeding events regardless of HBR and/or PCI complexity. For the thrombotic composite end point, the hazard ratio (HR) was 0.75 (95% CI, 0.53-1.04) among HBR vs 0.62 (95% CI, 0.48-0.80) among patients without HBR (P for interaction = 0.38) and 0.49 (95% CI, 0.32-0.77) among patients with complex PCI vs 0.74 (95% CI, 0.59-0.92) among patients with noncomplex PCI (P for interaction = 0.12). The reduction in bleeding by clopidogrel compared with aspirin was consistent among both patients with HBR (HR, 0.82; 95% CI, 0.56-1.21) and patients without HBR (HR, 0.58; 95% CI, 0.40-0.85; P for interaction = 0.20) and among patients undergoing complex PCI (HR, 0.79; 95% CI, 0.47-1.33) vs noncomplex PCI (HR, 0.68; 95% CI, 0.50-0.93; P for interaction = 0.62). Conclusions and Relevance: In this study, in patients who experienced PCI and were event-free during 6 to 18 months of DAPT, the beneficial impact of clopidogrel monotherapy over aspirin monotherapy was consistent, regardless of bleeding risk and/or PCI complexity. Trial Registration: ClinicalTrials.gov Identifier: NCT02044250.