Incidence of Acute Thrombosis After Surgical Left Atrial Appendage Occlusion for Atrial Fibrillation

BACKGROUND The clinical implications of acute phase thrombosis following surgical left atrial appendage (LAA) closure remain unclear. This study sought to determine the frequency, prognosis, and factors involved in thrombogenesis after surgical LAA occlusion. METHODS In this study, data from patients who underwent two types of stand-alone surgical LAA closure (either resection or clipping) between July 2014 and March 2020 at a single center were analyzed. RESULTS A total of 239 consecutive patients with atrial fibrillation (AF) underwent minimally invasive stand-alone surgical LAA occlusion (184 resection cases and 55 clipping cases). On postoperative day 2, electrocardiogram (ECG) synchronized contrast-enhanced computed tomography (CT) was performed in 223 cases (93.3%), and echocardiography follow-up was performed in 16 cases when CT was contraindicated. Acute postoperative thrombus on the closed stump was detected in 35 cases (14.7%), of which 29 cases (15.8%) belonged to the resection group and 6 cases (10.9%) belonged to the clipping group. No significant difference was detected between the groups, and no significant predictors of acute-phase thrombosis were found. Thromboembolism occurred in four patients before postoperative imaging follow-up, and there was no evidence of thrombi in these patients on postoperative day 2 CT. Three months after the first CT, thrombi were no longer detected in 34/35 patients (97.1%). CONCLUSIONS Thrombosis can occur after surgical LAA occlusion. Although the clinical significance is yet unclear, it may be reasonable to continue anticoagulation therapy for the first two days of the acute postoperative period.