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

Background: The clinical implications of acute phase thrombosis after 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 2 types of standalone 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 underwent minimally invasive standalone surgical LAA occlusion (184 resection cases and 55 clipping cases). On postoperative day 2, electrocardiogram 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 4 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 of 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 until a lack of thrombosis is confirmed, unless there are contraindications.