Percutaneous Interventions for Left Atrial Appendage Exclusion

Percutaneous left atrial appendage (LAA) exclusion is an evolving treatment to prevent embolic events in patients with nonvalvular atrial fibrillation. In the past few years multiple percutaneous devices have been developed to exclude the LAA from the body of the left atrium and thus from the systemic circulation. Twoand 3-dimensional transesophageal echocardiography (TEE) is used to assess the LAA anatomy and its suitability for percutaneous closure to select the type and size of the closure device and to guide the device implantation procedure in conjunction with fluoroscopy. In addition, 2and 3-dimensional TEE is also used to assess the effectiveness of device implantation acutely and on subsequent follow-up examination. Knowledge of the implantation options that are currently available along with their specific characteristics is essential for choosing the appropriate device for a given patient with a specific LAA anatomy. We present the currently available LAA exclusion devices and the echocardiographic imaging approaches for evaluation of the LAA before, during, and after LAA occlusion. (J Am Coll Cardiol Img 2015;8:472–88) © 2015 by the American College of Cardiology Foundation. T he left atrial appendage (LAA) is a tubular, blind-ended pouch attached to the main body of the left atrium (LA). It is the source of cerebral thromboembolism in approximately 90% of patients with nonvalvular atrial fibrillation (AF) (1,2). LAA occlusion or exclusion to prevent embolism in patients with nonvalvular AF by implanting a percutaneously delivered device to exclude the LAA cavity from the systemic circulation has evolved since the first implantation of an LAA occlusion device in 2001 (3). Currently there are 3 devices (Figure 1) available for percutaneous implantation within the LAA and one suture-based technology to occlude the LAA (Figure 2). European guidelines for management of AF now recommend that percutaneous LAA closure may be considered in high stroke risk patients with contraindications for long-term oral anticoagulation (class IIb indication, level of evidence B) (4). Transesophageal echocardiography (TEE) is the main imaging modality used to assess LAA anatomy, aid in the selection of a suitable device and size, and identify anatomic contraindications. Twodimensional (2D) and 3-dimensional (3D) TEE are used in conjunction with fluoroscopy to guide the procedure, evaluate results after device placement, and monitor for complications. In this review, we focus on current echocardiographic imaging approaches for the evaluation of the LAA before, during, and after LAA occlusion, and on the different imaging aspects in regard to the currently available devices. CURRENT DEVICES FOR PERCUTANEOUS LAA OCCLUSION OR EXCLUSION As shown in the Central Illustration, as well as in Figures 1 and 2, knowledge of the different devices and their characteristics is important for optimal patient selection and successful guidance of an LAA closure procedure. All LAA closure devices described in this review are available for clinical use in Europe. In the United States, the endoluminally implanted devices can only be used as part of a clinical trial. The LAA occluder device (Watchman device, Boston Scientific, Natick, Massachusetts) received FDA approval very recently in March 2015. The LAA ligation device (LARIAT suture device, SentreHEART, Inc., Redwood City, California) is approved by the Food and Drug Administration for suture placement and knot tying in surgical applications; however, it is not approved specifically for treatment of stroke prevention in patients with AF. ENDOLUMINAL LAA CLOSURE DEVICES. LAA occluder device. The LAA occluder device (Figure 1A) is a selfexpanding system with a nitinol frame covered with a permeable 160 mm polyethylene terephthalate fabric on the LA side of the device. Ten active fixation hooks are placed around the circumference. There are