Left atrial appendage occlusion plus oral anticoagulation in stroke patients despite ongoing anticoagulation: rationale and design of the ADD-LAAO clinical trial.

Introduction and objectives: The prevalence of atrial fibrillation and the number of patients experiencing ischemic strokes despite oral anticoagulation (OAC) are both on the rise, which presents a significant challenge due to the absence of clear and uniform treatment recommendations for these patients. To date, there is no formal combination merging into a high anticoagulant efficacy profile while keeping a low bleeding risk. Transcatheter left atrial appendage occlusion (LAAO) in combination with OAC might provide a balance between safety and efficacy. The objective of this study is to evaluate whether, in ischemic stroke patients, despite anticoagulation, the combination of LAAO plus long-term anticoagulation-direct oral anticoagulants or vitamin K antagonist when indicated-is associated with a lower rate of recurrent cardioembolic events at 12 months vs the optimal medical therapy recommended by the neurologist.

Methods: A total of 380 patients with ischemic stroke despite OAC will be included. Patients will be randomized on a 1:1 ratio to receive the optimal medical therapy (control) or the combination of LAAO plus OAC or OAC. The primary endpoint of the study will be the occurrence of a cardioembolic event-ischemic stroke or arterial peripheral embolism-within the first 12 months after inclusion.

Conclusions: This study is one of the first randomized clinical trials to compare the LAAO plus OAC combination and optimal medical therapy in patients who have experienced ischemic strokes despite being on OAC. If results confirm the superiority of LAAO plus OAC, it could lead to a paradigm shift in treatment guidelines for these patients.