Left atrial appendage closure for prevention of death, stroke, and bleeding in patients with nonvalvular atrial fibrillation.

Nonvalvular atrial fibrillation (AF) is the most frequent arrhythmia with a prevalence of 1%-2% in the general population. Its prevalence increases with age and its diagnosis benefits of improvement and simplification of technologies for its detection. Today, AF affects approximately 7% of individuals age>65years and 15%-20% of octogenarians. Due to stasis and activation of coagulation in a fibrillating atrium, patients are at increased risk of thromboembolism, in particular ischemic stroke, with an overall stroke risk of 5% per year. Since the left atrium itself is round and smooth-walled, thrombi typically do not form there, but almost exclusively in the left atrial appendage (LAA), a blind sac-like heterogeneous structure trabeculated by pectinate muscles. In the past five decades, oral anticoagulation (OAC) with vitamin K antagonists (VKA) has been the state-of-the art treatment to prevent stroke and systemic embolism from thrombi in AF. In the last decade, nonvitamin K dependant oral anticoagulants (NOAC) have been shown to be overall superior to VKA with respect to efficacy and safety in large trials and registries. Given the safety issues of indefinite OAC with either VKA or NOAC, it is plausible to consider left atrial appendage closure (LAAC) as an alternative strategy for prevention of all three catastrophes for patients with AF on anticoagulation: death, stroke or other systemic embolization, and bleeding. In the past years, LAAC has been compared to VKA in prospective randomized trials, yielding superior results regarding efficacy and non-inferiority regarding safety in the mid-term. Today, the decision to provide the most appropriate treatment for a patient with AF (OAC, NOAC, or LAAC) is complex and needs to be individualized. This review provides a comprehensive update on the current state of LAAC in the field of prevention of death, stroke and bleedings in patients suffering from nonvalvular AF. We describe the pathophysiology of the LAA with regard to stroke, elucidate the evidence and limitations of anticoagulation as the classical treatment paradigm, and review devices and techniques for LAAC. Most importantly, the current clinical evidence on efficacy and safety is outlined and finally, contemporary recommendations for patient selection are provided.