title: Left Atrial Appendage: Physiology, Pathology, and Role as a Therapeutic Target.
abstract: Atrial fibrillation (AF) is the most common clinically relevant cardiac arrhythmia. AF poses patients at increased risk of thromboembolism, in particular ischemic stroke. The CHADS2 and CHA2DS2-VASc scores are useful in the assessment of thromboembolic risk in nonvalvular AF and are utilized in decision-making about treatment with oral anticoagulation (OAC). However, OAC is underutilized due to poor patient compliance and contraindications, especially major bleedings. The Virchow triad synthesizes the pathogenesis of thrombogenesis in AF: endocardial dysfunction, abnormal blood stasis, and altered hemostasis. This is especially prominent in the left atrial appendage (LAA), where the low flow reaches its minimum. The LAA is the remnant of the embryonic left atrium, with a complex and variable morphology predisposing to stasis, especially during AF. In patients with nonvalvular AF, 90% of thrombi are located in the LAA. So, left atrial appendage occlusion could be an interesting and effective procedure in thromboembolism prevention in AF. After exclusion of LAA as an embolic source, the remaining risk of thromboembolism does not longer justify the use of oral anticoagulants. Various surgical and catheter-based methods have been developed to exclude the LAA. This paper reviews the physiological and pathophysiological role of the LAA and catheter-based methods of LAA exclusion.
authors.affiliation: Non-Invasive Cardiology, Cardio-Thoracic-Vascular Department, San Raffaele Scientific Institute, Via Olgettina 60, 20132 Milano, Italy.
authors.forename: Damiano
authors.initials: D
authors.lastname: Regazzoli
authors.affiliation: Non-Invasive Cardiology, Cardio-Thoracic-Vascular Department, San Raffaele Scientific Institute, Via Olgettina 60, 20132 Milano, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Ancona
authors.affiliation: Arrhythmology and Electrophysiology Unit, Cardio-Thoracic-Vascular Department, San Raffaele Scientific Institute, Via Olgettina 60, 20132 Milano, Italy.
authors.forename: Nicola
authors.initials: N
authors.lastname: Trevisi
authors.affiliation: Arrhythmology and Electrophysiology Unit, Cardio-Thoracic-Vascular Department, San Raffaele Scientific Institute, Via Olgettina 60, 20132 Milano, Italy.
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Guarracini
authors.affiliation: Arrhythmology and Electrophysiology Unit, Cardio-Thoracic-Vascular Department, San Raffaele Scientific Institute, Via Olgettina 60, 20132 Milano, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Radinovic
authors.affiliation: Non-Invasive Cardiology, Cardio-Thoracic-Vascular Department, San Raffaele Scientific Institute, Via Olgettina 60, 20132 Milano, Italy.
authors.forename: Michele
authors.initials: M
authors.lastname: Oppizzi
authors.affiliation: Non-Invasive Cardiology, Cardio-Thoracic-Vascular Department, San Raffaele Scientific Institute, Via Olgettina 60, 20132 Milano, Italy.
authors.forename: Eustachio
authors.initials: E
authors.lastname: Agricola
authors.affiliation: Arrhythmology and Electrophysiology Unit, Cardio-Thoracic-Vascular Department, San Raffaele Scientific Institute, Via Olgettina 60, 20132 Milano, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Marzi
authors.affiliation: Arrhythmology and Electrophysiology Unit, Cardio-Thoracic-Vascular Department, San Raffaele Scientific Institute, Via Olgettina 60, 20132 Milano, Italy.
authors.forename: Nicoleta Carmen
authors.initials: NC
authors.lastname: Sora
authors.affiliation: Arrhythmology and Electrophysiology Unit, Cardio-Thoracic-Vascular Department, San Raffaele Scientific Institute, Via Olgettina 60, 20132 Milano, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Della Bella
authors.affiliation: Arrhythmology and Electrophysiology Unit, Cardio-Thoracic-Vascular Department, San Raffaele Scientific Institute, Via Olgettina 60, 20132 Milano, Italy.
authors.forename: Patrizio
authors.initials: P
authors.lastname: Mazzone
mesh_terms: D000818:Animals; D000925:Anticoagulants / Q000627:therapeutic use; D020517:Atrial Appendage / Q000000981:diagnostic imaging / Q000473:pathology* / Q000503:physiopathology*; D003952:Diagnostic Imaging; D006801:Humans; D011859:Radiography; D012307:Risk Factors; D013923:Thromboembolism / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000517:prevention & control; D014463:Ultrasonography
chemical_list: D000925:Anticoagulants