Rationale and design of a randomized clinical trial to compare two antithrombotic strategies after left atrial appendage occlusion: double antiplatelet therapy vs. apixaban (ADALA study).

BACKGROUND: Data on antithrombotic therapy after percutaneous left atrial appendage occlusion (LAAO) is scarce and no randomized evaluation has been performed to demonstrate what is the best antithrombotic strategy. Up to date, different antithrombotic regimens with variable durations are currently used. In fact, the use of oral anticoagulation (OAC) or dual antiplatelet therapy (DAPT) with aspirin and clopidogrel during the initial phase (∓ 3 months post-LAAO) has been proposed as valid strategies. However, antiplatelet and OAC therapies have never been compared in a randomized study after left atrial appendage closure (LAAC). The purpose of the present study is to ascertain an optimal antithrombotic strategy after LAAC in terms of safety and efficacy. The study will compare a novel OAC (NOAC) with a highly safety profile like apixaban 5 mg/12 h or 2.5 mg/12 h (after dose adjustment or in high-risk patients) with standard antiplatelet therapy with DAPT. The aim of the study was to compare a strategy of anticoagulation with apixaban 5 mg/2.5 mg bid to the current standard of care (DAPT with aspirin and clopidogrel) after LAAO in patients with non-valvular atrial fibrillation (AF).

METHODS: This is a phase IV multicenter randomized, open-label, controlled trial comparing the efficacy and safety of apixaban vs. DAPT after LAAO, both for 3 months. The primary endpoint is a combined endpoint of death, myocardial infarction, stroke, thromboembolic complications, and major or significant bleeding at 3 months of follow-up. Approximately 160 subjects will be enrolled and followed 12 months from randomization.

CONCLUSIONS: Considering the high risk of both thromboembolic and hemorrhagic events of patients undergoing LAAO, establishment of an appropriate antithrombotic therapy in terms of efficacy and safety after LAAO is of vital importance.

TRIAL REGISTRATION: EudraCT number: 2018-001013-32.