ABSTRACT
Importance: Patients with atrial fibrillation (AF) who have ischemic stroke despite taking oral anticoagulation therapy (OAT) have a very high risk of recurrence. Left atrial appendage occlusion (LAAO) is a mechanical stroke prevention strategy that may provide additional protection in patients with thromboembolic events under OAT. Objective: To compare percutaneous LAAO with continuing OAT alone regarding stroke prevention in patients with AF who had a thromboembolic event despite taking OAT. Design, Setting, and Participants: This cohort study was a propensity score-matched comparison of the STR-OAC LAAO cohort, an international collaboration of 21 sites combining patients from multiple prospective registries of patients who underwent LAAO between 2010 and 2022. STR-OAC LAAO cohort patients who had follow-up longer than 3 months were propensity score-matched to a previously published control cohort comprising patients from an established international collaboration of investigator-initiated prospective studies. This control cohort included patients with nonvalvular AF, recent ischemic stroke or transient ischemic attack, and follow-up longer than 3 months who were taking OAT before the index event. Analyses were adjusted for imbalances in gender, age, hypertension, diabetes, and CHA2 DS2-VASc score. Exposure: Left atrial appendage occlusion vs continuation of oral anticoagulation therapy alone (control group). Main Outcomes and Measures: The primary outcome was time to first ischemic stroke. Results: Four hundred thirty-three patients from the STR-OAC LAAO cohort (mean [SD] age, 72 [9] years; 171 [39%] females and 262 [61%] males; mean [SD] CHA2 DS2-VASc score, 5.0 [1.6]) were matched to 433 of 1140 patients (38%) from the control group. During 2-year follow-up, 50 patients experienced ischemic stroke: an annualized event rate of 2.8% per patient-year in the STR-OAC LAAO group vs 8.9% per patient-year in the control group. Left atrial appendage occlusion was associated with a lower risk of ischemic stroke (hazard ratio, 0.33; 95% CI, 0.19-0.58; P < .001) compared with the control group. After LAAO, OAT was discontinued in 290 patients (67%), and the remaining 143 patients (33%) continued OAT after LAAO as an adjunctive therapy. Conclusions and Relevance: In patients with nonvalvular AF and a prior thromboembolic event despite taking OAT, LAAO was associated with a lower risk of ischemic stroke compared with continued OAT alone. Randomized clinical trial data are needed to confirm that LAAO may be a promising treatment option for this population with a very high risk of stroke.
ABSTRACT
BACKGROUND: Left atrial appendage occlusion (LAAO) provides mechanical cardioembolic protection for atrial fibrillation (AF) patients who cannot use oral anticoagulation therapy (OAT). Patients with a thrombotic event despite OAT are at high risk for recurrence and may also benefit from LAAO. OBJECTIVES: This study sought to investigate the efficacy of LAAO in AF patients with a thrombotic event on OAT compared to: 1) LAAO in AF patients with a contraindication for OAT; and 2) historical data. METHODS: The international LAAO after stroke despite oral anticoagulation (STR-OAC LAAO) collaboration included patients who underwent LAAO because of thrombotic events on OAT. This cohort underwent propensity score matching and was compared to the EWOLUTION (Evaluating Real-Life Clinical Outcomes in Atrial Fibrillation Patients Receiving the WATCHMAN Left Atrial Appendage Closure Technology) registry, which represents patients who underwent LAAO because of OAT contraindications. The primary outcome was ischemic stroke. Event rates were compared between cohorts and with historical data without OAT, yielding relative risk reductions based on risk scores. RESULTS: Analysis of 438 matched pairs revealed no significant difference in the ischemic stroke rate between the STR-OAC LAAO and EWOLUTION cohorts (2.5% vs 1.9%; HR: 1.37; 95% CI: 0.72-2.61). STR-OAC LAAO patients exhibited a higher thromboembolic risk (HR: 1.71; 95% CI: 1.04-2.83) but lower bleeding risk (HR: 0.39; 95% CI: 0.18-0.88) compared to EWOLUTION patients. The mortality rate was slightly higher in EWOLUTION (4.3% vs 6.9%; log-rank P = 0.028). Relative risk reductions for ischemic stroke were 70% and 78% in STR-OAC LAAO and EWOLUTION, respectively, compared to historical data without OAT. CONCLUSIONS: LAAO in patients with a thrombotic event on OAT demonstrated comparable stroke rates to the OAT contraindicated population in EWOLUTION. The thromboembolic event rate was higher and the bleeding rate lower, reflecting the intrinsically different risk profile of both populations. Until randomized trials are available, LAAO may be considered in patients with an ischemic event on OAT.