Optimal Therapy for Stroke Prevention in Atrial Fibrillation: Is it Left Atrial Appendage Closure?

Sarris-Michopoulos et al. reviewed the role of the left atrial appendage (LAA) in atrial fibrillation (AF) related stroke and current techniques for targeting it for stroke reduction. 1The authors propose that further trials to assess LAA exclusion as an alternative to anticoagulation for patients with AF should strongly be considered.Any such consideration should take into account the potential risks and benefits, and ultimately be supported by randomized clinical trial data.The latter is lacking at the present time, so we will consider the potential risks and benefits.The LAA is often considered to be a vestigial portion of the left atrium; however, it does have a physiologic role in humans.The LAA is a remnant of the embryonic left atrium that develops during the third week of fetal life. 2 It has several functions that continue into adulthood including serving as a reservoir during left ventricular systole, a conduit for blood from the pulmonary veins into the left ventricle during diastole, a chamber to augment left ventricular filling in late diastole, and a filling chamber for volume reserve. 2 Furthermore, the LAA plays an important endocrine role.It contains stretch receptors to excrete atrial natriuretic peptide in response to changes in left atrial pressure to increase natriuresis. 2Removal of the LAA eliminates these functional roles.Interestingly, it has been shown that patients undergoing LAA exclusion have elevated left atrial pressure. 3