ÌÇÐÄvlog

QuestionÌý What is the optimal antithrombotic therapy after percutaneous left atrial appendage occlusion (LAAO)?

FindingsÌý In this randomized clinical trial that included 90 participants, low-dose direct oral anticoagulation (low-dose DOAC) showed a better balance between efficacy (less device-related thrombosis, equal thromboembolism events) and safety (equal major bleeding) compared with dual antiplatelet therapy after LAAO.

MeaningÌý Results suggest that low-dose DOAC may be an effective and safe antithrombotic therapy for patients after LAAO.

ImportanceÌý Optimal antithrombotic therapy after percutaneous left atrial appendage occlusion (LAAO) is not well established as no randomized evaluation has been performed to date.

ObjectiveÌý To compare the efficacy and safety of low-dose direct oral anticoagulation (low-dose DOAC) vs dual antiplatelet therapy (DAPT) for 3 months after LAAO.

Design, Setting, and ParticipantsÌý The ADALA (Low-Dose Direct Oral Anticoagulation vs Dual Antiplatelet Therapy After Left Atrial Appendage Occlusion) study was an investigator-initiated, multicenter, prospective, open-label, randomized clinical trial enrolling participants from June 12, 2019, to August 28, 2022 from 3 European sites. Patients who underwent successful LAAO were randomly assigned 1:1 to low-dose DOAC vs DAPT for 3 months after LAAO. The study was prematurely terminated when only 60% of the estimated sample size had been included due to lower recruitment rate than anticipated due to the COVID-19 pandemic.

InterventionsÌý The low-dose DOAC group received apixaban, 2.5 mg every 12 hours, and the DAPT group received aspirin, 100 mg per day, plus clopidogrel, 75 mg per day, for the first 3 months after LAAO.

Main Outcomes and MeasuresÌý The primary end point was a composite of safety (major bleeding) and efficacy (thromboembolic events including stroke, systemic embolism, and device-related thrombosis [DRT]) within the first 3 months after successful LAAO. Secondary end points included individual components of the primary outcome and all-bleeding events.

ResultsÌý A total of 90 patients (mean [SD] age, 76.6 [8.1] years; 60 male [66.7%]; mean [SD] CHADS-VASc score, 4.0 [1.5]) were included in the analysis (44 and 46 patients in the low-dose DOAC and DAPT groups, respectively). A total of 53 patients (58.8%) presented with previous major bleeding events (60 gastrointestinal [66.7%] and 16 intracranial [17.8%]). At 3 months, low-dose DOAC was associated with a reduction of the primary end point compared with DAPT (2 [4.5%] vs 10 [21.7%]; hazard ratio, 0.19; 95% CI, 0.04-0.88; P = .02). Patients in the low-dose DOAC group exhibited a lower rate of DRT (0% vs 6 [8.7%]; P = .04) and tended to have a lower incidence of major bleeding events (2 [4.6%] vs 6 [13.0%]; P = .17), with no differences in thromboembolic events such as stroke and systemic embolism between groups (none in the overall population).

Conclusions and RelevanceÌý This was a small, randomized clinical trial comparing different antithrombotic strategies after LAAO. Results show that use of low-dose DOAC for 3 months after LAAO was associated with a better balance between efficacy and safety compared with DAPT. However, the results of the study should be interpreted with caution due to the limited sample size and will need to be confirmed in future larger randomized trials.

Trial RegistrationÌý ClinicalTrials.gov Identifier: