Left atrial appendage-occluding devices for stroke prevention in patients with nonvalvular atrial fibrillation.

Atrial fibrillation is associated with a fivefold increased risk for stroke, mostly secondary to thromboembolic events. Anticoagulation with a vitamin K antagonist is the standard medical therapy for these patients but is difficult to maintain within the therapeutic range and requires frequent monitoring and dose adjustments. Approximately 90% of thromboembolism occurs in the left atrial appendage (LAA) in patients with nonvalvular atrial fibrillation. Occlusion of flow into the LAA may prevent thrombus formation in the appendage and, hence, reduction of stroke. Recently, several percutaneous transcatheter techniques of LAA exclusion using the Percutaneous Left Atrial Appendage Transcatheter Occlusion device, the WATCHMAN device, and AMPLATZER septal occluder and cardiac plug have been employed, with encouraging results. Occlusion of the LAA may be an alternative to vitamin K antagonist therapy for selected patients.