Left Atrial Appendage Occlusion/Exclusion: Procedural Image Guidance with Transesophageal Echocardiography

Abstract

Atrial fibrillation is the most common arrhythmia worldwide and is a major risk factor for embolic stroke. In this article, the authors describe the crucial role of two- and three-dimensional transesophageal echocardiography in the pre- and postprocedural assessment and intraprocedural guidance of percutaneous left atrial appendage (LAA) occlusion procedures. Although recent advances have been made in the field of systemic anticoagulation with the novel oral anticoagulants, these medications come with a significant risk for bleeding and are contraindicated in many patients. Because thromboembolism in atrial fibrillation typically arises from thrombi originating in the LAA, surgical and percutaneous LAA exclusion/occlusion techniques have been devised as alternatives to systemic anticoagulation. Currently, surgical LAA exclusion is typically performed as an adjunct to other cardiac surgical procedures, which limits the number of eligible patients. Recently, several percutaneously delivered devices for LAA exclusion from the systemic circulation have been developed, some of which have been shown in clinical trials to reduce the risk for thromboembolism. These devices use an either purely endocardial LAA occlusion approach, such as the Watchman and Amulet procedures, or both an endocardial and a pericardial (epicardial) approach, such as the Lariat procedure. In the Watchman and Amulet procedures, a transseptally delivered structure composed of nitinol is placed in the LAA orifice, thereby excluding the LAA from the systemic circulation. In the Lariat procedure, a magnet link is created between a transseptally delivered endocardial wire and epicardially delivered pericardial wire, followed by epicardial suture ligation of the LAA.