Left Atrial Appendage Occlusion: What Are the Options and Where is the Evidence?

Abstract

Left atrial appendage occlusion (LAAO) has emerged as an effective site-directed therapy in patients with nonvalvular atrial fibrillation (AF) for stroke prevention, who are ineligible for long-term oral anticoagulation. The objective of this study was to assess the safety, efficacy, and availability of LAAO devices by reviewing the literature and to review the development and effectiveness of LAAO by the transcatheter approach with plugging devices such as WATCHMAN™ (Boston Scientific, Natick, MA, USA); AMPLATZER™ Cardiac Plug and AMPLATZER™ Amulet™ (Abbott Laboratories, Chicago, IL, USA); and the LARIAT^® Suture Delivery Device (SentreHEART, Redwood City, CA, USA), which features an entirely unique hybrid (endocardial and epicardial) approach in closing the left atrial appendage (LAA). The conducted literature review ultimately revealed a substantial body of literature supporting the safety and efficacy of various LAAO strategies, including endocardial, epicardial, and hybrid approaches, in AF patients who are not eligible for long-term oral anticoagulant use. Specifically, the most attractive population suitable for LAA closure appears to be patients at high risk for ischemic stroke with a longer life expectancy but a moderate-to-high bleeding risk with long-term oral anticoagulation. The benefit of LAA closure in reducing the incidence of stroke in patients with nonvalvular AF has been evolving gradually, and we are confident that this new field of percutaneous LAA closure will continue to emerge as a game-changer in the treatment of AF.

Keywords: Amulet; WATCHMAN™; anticoagulation; left atrial appendage; thromboembolism.

Figure 1:

The WATCHMAN™ device (Boston Scientific, Natick, MA, USA) this device is made of a self-expanding nitinol frame with a polyethylene terephthalate fabric cap. Distal tines secure the device within the LAA trabeculae. It is fully retrievable prior to release from the delivery cable. The device’s length is approximately equal to its diameter. Device size is selected on the basis of the largest diameter of the LAA ostium, which is measured by drawing a line from the mitral valve annulus across to the ridge of the left upper pulmonary vein, perpendicular to the planned axis of the delivery sheath. Alternatively, the LAA ostium can be measured from the mitral valve annulus to a point ≈ 2 cm distal from the tip of the left upper pulmonary vein ridge. Image courtesy of Boston Scientific.

Figure 2:

The AMPLATZER™ Cardiac Plug (Abbott Laboratories, Chicago, IL, USA). This device is a self-expanding nitinol mesh that consists of a distal lobe and proximal disk, connected by a short central waist and covered with a sewn polyester patch. During use, the distal lobe hooks around its circumference and anchors the device within the appendage, with the disk positioned proximally and occluding the mouth of the LAA. A: lobe; B: disc; C: waist; D: stabilizing wire; E: radiopaque markers; F: radiopaque threads.

Figure 3:

The AMPLATZER™ Amulet™ LAA occlusive device (Abbott Laboratories, Chicago, IL, USA). Image courtesy of Abbott Laboratories.

Figure 4:

The LARIAT^® ligation device (SentreHEART, Redwood City, CA, USA). Video 1 (available online) demonstrates the insertion process.

Figure 5:

The Coherex WaveCrest™ LAA occlusion system (Coherex Medical, Salt Lake City, UT, USA).

Figure 6:

An algorithm of stroke prevention in AF. AF: atrial fibrillation; LAA: left atrial appendage; NOAC: novel oral anticoagulant; OAC: oral anticoagulant; VKA: vitamin K antagonist.