To the Editor Dr Yao and colleagues identified an association between left atrial appendage occlusion (LAAO) and reduced risk of stroke and all-cause mortality after cardiac surgery in a large insurance database (75 782 patients).1 There are limitations of the study that require careful consideration.
The authors attempted to identify patients undergoing coronary artery bypass graft or valve procedures and subsequently stratified by whether they underwent concomitant LAAO.1 Inherent to the study design, there was incomplete analysis regarding concomitant surgical ablation (Maze) procedures performed at the time of cardiac surgery. Maze procedures have been shown to independently reduce the rate of stroke and late mortality in patients presenting with atrial fibrillation (AF).2,3 Table 2 in the article showed that 24.4% of patients undergoing LAAO underwent a concomitant Maze procedure, while only 1.6% not undergoing LAAO underwent a Maze procedure.1 In an analysis using the Society of Thoracic Surgeons database (a nationwide validated and comprehensive clinical database), 94% of patients undergoing LAAO underwent a concomitant Maze procedure, while 12% underwent a Maze procedure without LAAO.4 It is unclear whether the OptumLabs Data Warehouse accurately captures concomitant Maze procedures.1 Given the marked difference in the frequency of concomitant Maze procedures performed among patients who had and did not have LAAO, the difference in stroke rates and all-cause mortality may have been attributable to concomitant Maze procedures, rather than LAAO independently. Consequently, we agree with the authors that randomized clinical trials are necessary to determine the role of routine use of LAAO in patients undergoing cardiac surgery.
Coyan GN, Gleason TG, Chu D. Left Atrial Appendage Occlusion and Surgical Ablation for Atrial Fibrillation During Cardiac Surgery. JAMA. 2018;320(15):1602. doi:10.1001/jama.2018.11332
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