Contemporary Review of Left Atrial Appendage Occlusion in Atrial Fibrillation

Atrial fibrillation (AF) is the most common cardiac arrhythmia worldwide and a major contributor to ischemic stroke and cardioembolic events. Although oral anticoagulation remains the cornerstone of stroke prevention in AF, its use may be limited by bleeding risk, contraindications, intolerance, and adherence challenges. Because the left atrial appendage (LAA) is the predominant site of thrombus formation in nonvalvular AF, LAA closure has emerged as a mechanistically targeted, non-pharmacologic approach to reduce embolic risk in selected patients. This review critically appraises the evidence supporting surgical and percutaneous LAA occlusion, with emphasis on AF-related thromboembolism, the role of the LAA in thrombogenesis, procedural techniques, patient selection, peri-procedural multimodality imaging, clinical outcomes, and complications. Surgical LAA occlusion performed during concomitant cardiac surgery has been shown in randomized trials and meta-analyses to reduce ischemic stroke and systemic embolism and is endorsed by major society guidelines as an adjunct to continued anticoagulation in eligible patients. Percutaneous LAA closure with contemporary devices, including Watchman FLX and Amulet, offers an alternative to long-term anticoagulation for selected patients with nonvalvular AF and elevated bleeding risk, although randomized trial findings remain mixed. Evidence in special populations, including patients with prosthetic valves, advanced age, chronic kidney disease, congenital heart disease, and prior LAA occlusion, is also reviewed, highlighting unique procedural considerations and persistent knowledge gaps. Continued investigation is needed to refine patient selection across AF phenotypes, standardize post-closure antithrombotic and imaging follow-up strategies, and clarify the net benefit of prophylactic surgical LAA occlusion in patients without pre-existing AF. A multidisciplinary, individualized approach remains essential to balancing thromboembolic and bleeding risks and optimizing patient outcomes.