Half-dose anticoagulation versus antiplatelet therapy to reduce silent cerebral embolism after left atrial appendage occlusion (HALO-SCE study): Rationale and design of a randomized clinical trial

Introduction: Patients with atrial fibrillation (AF) continue to face thrombotic risks even after the left atrial appendages (LAA) have been occluded, which may manifest as silent cerebral embolisms (SCEs). Half-dose anticoagulation (Hd-OAC) is a pathophysiologically more reasonable therapy in addressing this issue than antithrombotic therapy, but it still lacks strong evidence. Methods: The trial (NCT05671276) is a multicenter, randomized controlled trial comparing the efficacy of two antithrombotic strategies (Hd-OAC therapy vs. standard antithrombotic therapy) in AF patients after left atrial appendages occlusion (LAAO). The primary endpoint is the incidence of newly detected SCEs on any magnetic resonance imaging conducted during the follow-up period. The secondary endpoints are (1) more than two new SCEs during the follow-up, their size and distribution, (2) cognitive function, and (3) a composite endpoint of all-cause mortality, clinical thromboembolic events, and major bleeding events. Follow-up is scheduled at 90±15 days, 180±15 days, and 365±15 days after LAAO. Conclusions: This trial aims to determine whether Hd-OAC therapy can reduce the incidence of SCE and protect cognitive function in patients who have successfully undergone LAAO, compared to standard antithrombotic therapy. Trial Registration: ClinicalTrials.gov: NCT05671276.