[Left atrial appendage occlusion in patients with nonvalvular atrial fibrillation : Present evidence, ongoing studies, open questions].

About every fifth ischemic stroke is caused by atrial fibrillation. Oral anticoagulation is highly effective in secondary stroke prevention, but a relevant portion of patients with atrial fibrillation is not (permanently) anticoagulated for a variety of reasons. Based on present evidence, no general recommendation can be given for left atrial appendage occlusion in patients with nonvalvular atrial fibrillation. However, left atrial appendage occlusion is a treatment option after severe anticoagulation-related bleeding, if the cause of bleeding is not treatable. Left atrial appendage occlusion is critical in patients with a relative contraindication for oral anticoagulation or lack of adherence to given medication. It seems to be important that further randomized studies confirm a benefit of left atrial appendage occlusion in selected patients with nonvalvular atrial fibrillation. In addition, it is vital to clarify whether discontinuation of antiplatelets is feasible after catheter-based left atrial appendage occlusion, as antiplatelets are associated with a risk of bleeding. Within this review article, we discuss present evidence, gaps of knowledge and provide an overview on ongoing clinical studies. In addition, we summarize the design of the CLOSURE-AF study. This randomized multicenter study will start recruitment soon and is funded by the German Center for Cardiovascular Research e. V.