Left atrial appendage occlusion: rationale, evidence, devices, and patient selection

Atrial fibrillation (AF) is a worldwide epidemic associated with significant morbidity and mortality, often due to disabling or fatal thromboembolic stroke. Oral anticoagulation is highly effective at preventing ischaemic stroke and improving all-cause survival in patients with nonvalvular AF. Despite the efficacy of oral anticoagulation, many patients are not treated due to either absolute or perceived contraindications to therapy, including bleeding. Left atrial appendage (LAA) closure has emerged as a mechanical alternative to pharmacologic stroke prevention. Initial and mid-term clinical trial data suggest that LAA closure is safe, with less intracranial bleeding, and a net clinical benefit that appears to be non-inferior to oral anticoagulation. However, concern remains over the possible increased risk of ischaemic stroke in long-term follow-up. Careful patient selection for LAA closure is paramount. Patients with prior intracranial bleeding or recurrent serious bleeding who are not eligible for long-term oral anticoagulation are typical candidates for LAA closure; however, other populations may benefit as well, such as patients with end-stage renal disease. Clinical investigation and randomized trials are needed to clarify the best methods of LAA occlusion, optimal pharmacologic strategies in the short-term after LAA closure, and to identify patient populations who will derive the most benefit from LAA occlusion. In this article, we review the rationale for LAA closure, the currently available devices and their evidence base, patient selection, challenges in management, and future directions for LAA closure science.