Indexed on: 30 Oct '17Published on: 18 Oct '17Published in: Current Cardiovascular Imaging Reports
Atrial fibrillation (AF) is the most common arrhythmia in humans. It is a major cause of morbidity and mortality as it impairs cardiac function and is a major risk of embolic stroke. Traditionally, thromboembolic risk of AF has been treated with system anticoagulation with intravenous, intramuscular, or oral anticoagulants. Although the novel oral anticoagulants (NOACs) have revolutionized stroke risk reduction in AF patients, they are associated with a significant risk of bleeding and may be contraindicated in certain patients. Embolic events in AF typically originate from thrombi that form within the left atrial appendage (LAA), especially in nonvalvular AF. Both surgical and percutaneous LAA closure techniques have been devised as alternatives to systemic anticoagulation. As surgical LAA closure is typically performed as an adjunct to other cardiac surgeries, the amount of eligible patients for this type of therapy may be limited.Excluding the LAA from the systemic circulation may reduce the risk of thromboembolism in AF. Recent technologic advances have led to the development of several percutaneously delivered devices that can occlude or exclude the LAA from systemic circulation. These devices may be purely endocardially delivered such as the Watchman (Boston Scientific, Maple Grove, MN) and Amulet (St. Jude Medical, Minneapolis, MN), or both endocardially and pericardially delivered such as the Lariat (Sentre-HEART, Palo Alto, CA). During Amulet and Watchman procedures, a transseptally delivered device composed of nitinol is placed in the LAA orifice, subsequently 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. Their use is steadily increasing in worldwide either through routine clinical use of approved devices or within clinical trials.In this review, we describe the various devices available for percutaneous LAA closure, and the indispensable role of real-time transesophageal echocardiography in the periprocedural assessment and intraprocedural guidance of percutaneous LAA occlusion procedures.