Arzamendi, Dabit

BACKGROUND: The optimal antithrombotic treatment after transcatheter left atrial appendage closure (LAAC) remains to be determined. The objective of this trial was to compare anticoagulation and antiplatelet therapy for preventing device-related thrombosis (DRT) after LAAC. METHODS: This was a prospective multicenter international randomized trial comparing 2 different antithrombotic strategies for preventing DRT after LAAC in patients with nonvalvular atrial fibrillation. Patients were randomized (1:1) to receive direct oral anticoagulants (DOACs) or dual antiplatelet therapy (DAPT; aspirin+clopidogrel) for 60 days. Patients underwent transesophageal echocardiography at 60 days, and the images were analyzed in a central echocardiography laboratory by experienced echocardiographers blinded to the allocated treatment. The primary outcome was DRT as determined by transesophageal echocardiography 60 days after LAAC in patients receiving the allocated treatment at the time of transesophageal echocardiography (per-protocol analysis). The safety outcome included all-cause mortality, stroke, bleeding, or site-reported DRT within 60 days after LAAC in all randomized patients (intention-to-treat analysis). RESULTS: A total of 510 patients (mean age 77±9 years, 35% women) were included between October 2018 and May 2025, and 253 and 257 patients were randomized to the DOAC and DAPT groups, respectively. Of these, 399 patients underwent transesophageal echocardiography and were receiving the allocated treatment at 60 days after LAAC. The primary outcome occurred in 3 patients (1.5%) in the DOAC group compared with 8 patients (4.1%) in the DAPT group (difference, −2.7% [95% CI, −6.0% to 0.6%]; P =0.110). The safety outcome occurred in 52 patients (22.5%) in the DOAC group compared with 82 patients (34.9%) in the DAPT group (difference, −12.4% [95% CI, −20.6% to −4.2%]; P =0.003), and differences were mainly driven by a lower rate of bleeding events in the DOAC group (44 patients [17.4%] versus 64 patients [24.9%]; difference, −7.5% [95% CI, −14.6% to −0.4%]; P =0.038). CONCLUSIONS: The use of DOACs after LAAC failed to reduce DRT compared with DAPT, but it was associated with an improved safety profile. The results of this study should be interpreted with caution because of statistical power issues related to the narrower-than-expected between-group differences and will need confirmation in future larger studies. REGISTRATION: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT03568890.

ImportancePatients 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.ObjectiveTo 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 ParticipantsThis 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.ExposureLeft atrial appendage occlusion vs continuation of oral anticoagulation therapy alone (control group).Main Outcomes and MeasuresThe primary outcome was time to first ischemic stroke.ResultsFour 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 RelevanceIn 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.