Trial emulation of percutaneous left atrial appendage occlusion versus direct oral anticoagulants.

BACKGROUND: The use of percutaneous left atrial appendage occlusion (pLAAO) has increased in the past several years, as an alternative to oral anticoagulants in patients with atrial fibrillation (AF). The pivotal trials that led to pLAAO approval had small sample size and their populations differ from real-world patients who undergo pLAAO. OBJECTIVE: To compare pLAAO to direct oral anticoagulants (DOACs) in Medicare beneficiaries with AF. DESIGN: We created a retrospective cohort to emulate a target trial, from Jan 1st, 2015 to Dec 31st, 2020. Patients were identified from a 15% nationally representative sample of Medicare beneficiaries. We mimicked randomization using propensity score matching, and assigned patients to receive pLAAO or DOACs in a 1:3 ratio. The primary efficacy composite outcome was stroke, transient ischemic attack (TIA), or systemic thromboembolism. The primary safety outcome was bleeding events leading to hospital admission. RESULTS: After matching, we included 3,692 patients in the pLAAO group and 11,076 in the DOACs group. The mean age of patients was 78.5 years and 46.6% were women. The mean follow-up time was 2.4 years. The rate of the primary composite endpoint was not significantly different between pLAAO and DOACs (0.66/100 person-year vs. 0.47/100 person-year, HR: 1.38, 95% CI: 0.98 – 1.95). Bleeding events leading to hospitalization were significantly more common with pLAAO (5.30/100 person-year vs. 3.25/100 person-year, HR: 1.58, 95% CI: 1.38 – 1.79). CONCLUSIONS: In Medicare patients with AF, the rate of stroke, TIA or systemic thromboembolism was not significantly different between pLAAO and DOACs. Bleeding outcomes should be interpreted with caution, as residual confounding and variations in medication use over time may have influenced these findings.