Surgical left atrial appendage ligation is frequently incomplete: a transesophageal echocardiographic study

OBJECTIVES This study sought to determine the incidence of incomplete ligat ion of the left atrial appendage (LAA) during mitral valve surgery. BACKGROUND Ligation of the LAA to prevent future thromboembolic events is c ommonly performed during mitral surgery. However, success in completely exc luding the appendage from the circulation has never been systematically ass essed. METHODS Using transesophageal Doppler echocardiography we studied 50 patien ts who underwent mitral valve surgery and ligation of the LAA. Thirty patie nts were studied immediately postoperative, and 20 patients were studied 6 days to 13 years after surgery. Incomplete ligation was detected by demonst rating a color jet traversing the separation between the left atrial body a nd appendage. RESULTS Transesophageal echocardiography detected incomplete LAA ligation i n 18 of 50 (36%) patients. The incidence of incomplete ligation was not sig nificantly different between patients studied immediately postoperative and patients studied at various times after surgery. Type of mitral surgery (r epair vs, replacement), operative approach (sternotomy vs. port access), le ft atrial size or degree of mitral regurgitation did not significantly corr elate with the incidence of incomplete appendage ligation. However, the pow er to detect a significant difference in left atrial size was only 64%. Spo ntaneous echo contrast or thrombus was identified within appendages in 9 of 18 (50%) patients with incomplete ligation, while 4 of these 18 (22%) pati ents had thromboembolic events. CONCLUSIONS Surgical LAA ligation is frequently incomplete. The similar inc idence of in complete ligation detected immediately postoperative and at va rious times thereafter suggest that this results from an intraoperative phe nomenon rather than from gradual dehiscence of sutures over years. The inci dence of incomplete left atrial ligation was unrelated to type of surgery, surgical approach, left atrial size or degree of mitral regurgitation. Resi dual communication between the incompletely ligated appendage and the left atrial body may produce a milieu of stagnant blood flow within the appendag e and be a potential mechanism for embolic events. (C) 2000 by the American College of Cardiology.