Understanding The Role Of Blood Thinners & LAA Closure In Managing Atrial Fibrillation

Atrial fibrillation (AF), a common cardiac arrhythmia, is associated with an increased risk of stroke. Blood thinners, such as oral anticoagulants, have been the mainstay of stroke prevention in AF patients. Left atrial appendage (LAA) closure is another viable alternative for patients who can’t tolerate or are at increased risk of bleeding from blood thinners.

All patients with AF who are being considered for cardiac interventions need a thorough assessment consisting of cardiac history relating to the presence of AF, major structural or functional heart disease, potential causes of bleeding, and alternative causes of stroke beyond AF. Routine investigations, including basic laboratory tests and a 12-lead surface electrocardiogram (ECG), are fundamental before a patient is considered for Left Atrial Appendage Closure (LAAC) therapy - a procedure that involves implantation of a device to prevent blood clots from leaving the LAA and entering the bloodstream.

Establishing the Need for Thromboembolic Protection:

Risk assessment tools like the CHA2DS2-VASc score–which evaluates stroke risk and the HAS-BLED score–which assesses bleeding risk, are important to establish thromboembolic protection in AF patients. Any additional factor that could increase thromboembolic or bleeding risk requires documentation for determining the appropriate therapeutic strategy.

Pre-Procedural Diagnostic Workup:

Before proceeding with LAAC, a comprehensive diagnostic workup including transoesophageal echocardiography (TOE) or cardiac computed tomography (CT) is required to analyse the anatomy of the Left Atrial Appendage (LAA) and determine its suitability for closure. These imaging modalities also rule out LAA thrombosis, as the presence of a thrombus is generally a contraindication for LAAC. Thrombosis is excluded using TOE or intracardiac echocardiography (ICE) at the onset of the procedure.

Device Selection and Procedural Planning:

The selection of an LAA closure device and its size is guided by the operator's experience and the anatomical details obtained from pre-procedural workup, peri-procedural TOE or ICE, and selective LAA angiography. Cardiac CT provides a more detailed understanding of LAA anatomy and allows for precise measurements. For patients on direct oral anticoagulants (DOACs) like rivaroxaban, edoxaban, apixaban, and dabigatran, the treatment regimen is often adjusted before the procedure with the last dosage being stopped one day before the procedure as suggested by the doctor. 

Methods of Percutaneous Left Atrial Appendage Closure:

LAAC is a standardised procedure that requires specialised training for the implanter and the interventional team. It is commonly performed under general anaesthesia, guided by TOE. However, the increasing use of ICE or micro-/mini-TOE allows it to be conducted with local analgesia and light sedation, offering greater flexibility in patient management.

Procedural Steps

Femoral Venous Puncture: This step involves gaining venous access under ultrasound guidance, to minimise vascular complications.

Transseptal Access: Achieving transseptal access is critical for safely entering the left atrium and deploying the LAAC device.

Deployment of the Occluder: The deployment of the occluder within the LAA is guided by procedural imaging modalities such as TOE or ICE, with additional fluoroscopic control. Fusion of pre-procedural CT images with fluoroscopy additionally is occasionally used to enhance accuracy. Devices commonly used in this procedure include WATCHMAN FLX, AMPLATZER AMULET-ACP, LAmbre, and LARIAT. Final confirmation of device placement and the complete sealing of the LAA is confirmed through transoesophageal echocardiogram or intracardiac echo, ensuring optimal outcomes for the patient.

Managing Atrial Fibrillation through LAAC with or as an alternative to blood thinners is a tailored approach to reduce stroke risk in patients with AF. Proper patient selection, comprehensive diagnostic workup, and meticulous procedural planning are critical in achieving successful outcomes in LAAC therapy. As technology advances and procedural techniques evolve, the role of LAAC in managing AF will continue to expand, providing a vital option for patients who are at high risk of thromboembolic events.

The author is  HOD & Consultant - Interventional Cardiology, Manipal Hospital

Dr. Ranjan Shetty

Guest Author HOD & Consultant - Interventional Cardiology, Manipal Hospital Old Airport Road