Monotherapy Versus Combination Therapy Beyond 12 Months After Coronary Intervention in Older Atrial Fibrillation Patients.

BACKGROUND: Atrial fibrillation with coronary artery disease poses therapeutic challenges. Although guidelines recommend de-escalating to oral anticoagulant agent monotherapy >12 months after percutaneous coronary intervention (PCI), real-world data on major adverse cardiovascular events (MACE) and major bleeding in older adults remain limited. OBJECTIVES: The authors aimed to compare outcomes of monotherapy vs oral anticoagulant agent plus antiplatelet combination therapy in a large Japanese cohort. METHODS: Using a retrospective cohort from 20 municipalities, we identified patients aged ≥65 years with atrial fibrillation undergoing antithrombotic therapy 12-15 months post-PCI. We compared monotherapy against combination therapy using inverse probability of treatment weighting. The primary outcomes were MACE and major bleeding. Robustness was investigated using negative control outcomes, propensity score matching, competing risk, and recurrent event analyses. RESULTS: We analyzed 3,630 patients (monotherapy: n = 1,438; combination therapy: n = 2,192; median follow-up: 23.5 months [IQR: 11.8-38.6]). Compared with combination therapy, monotherapy showed no clear difference in MACE (HR: 0.96; 95% CI: 0.82-1.12) and was associated with a lower risk of major bleeding (HR: 0.79; 95% CI: 0.65-0.97). Associations were directionally consistent across sensitivity analyses. Monotherapy was associated with a lower rate of recurrent nonfatal MACE (rate ratio: 0.72; 95% CI: 0.59-0.88). CONCLUSIONS: De-escalation to monotherapy >12 months post-PCI was associated with reduced bleeding risk and comparable ischemic outcomes. Low cumulative ischemic event burden with monotherapy was an exploratory finding requiring confirmation. These real-world findings complement randomized trials favoring oral anticoagulant agent monotherapy over combination therapy in older patients beyond 12 months post-PCI.