Incomplete surgical ligation of the left atrial appendage—time for a new look at an old problem

Atrial fibrillation (AF) is the most common cardiac arrhythmia affecting an estimated 6 million individuals in the US (1). In patients with non-valvular AF, the risk of ischemic stroke/systemic embolization is nearly 5-fold greater after adjusting for all other risk factors (1). The left atrial appendage (LAA) has been identified as a common site of thrombus formation in patients with AF (2). As such, the LAA has been targeted for surgical closure using a variety of techniques for over 6 decades, a practice that is frequently performed in conjunction with mitral valve and AF surgery (3,4). However, surgical LAA exclusion can often yield incomplete LAA closure (5,6) which may in turn be associated with increased risk of thromboembolism (7). The latest studies have suggested a possible improvement in the rate of successful LAA closure using contemporary exclusion techniques such as endoscopic stapling or external clipping (8,9). However, these investigations have been uncontrolled and non-randomized. In fact, in a recent prospective randomized controlled study of patients undergoing AF surgery with concomitant LAA closure, Lee et al. (10) discovered that incomplete surgical LAA closure continues to remain a frequent and under-recognized clinical entity irrespective of closure technique.