Abstract Body (Do not enter title and authors here): Introduction: Thrombus in the left atrial appendage (LAA) is known to be one of the risk factors for ischemic stroke, and after the detection of LAA thrombus, anticoagulation therapy is usually administered. However, the role of anticoagulation therapy before the detection of LAA thrombus in the prognosis is still unclear.
Hypothesis: We assessed the hypothesis that the anticoagulation status at the time of LAA thrombus detection with transesophageal echocardiography (TEE) affects the future incidence of ischemic stroke.
Methods: Patients who underwent TEE and were found to have LAA thrombus were included. Patients were divided into two groups based on their anticoagulation status before TEE. To exclude strokes that might occur due to the detected LAA thrombus itself, landmark analysis was performed by excluding patients who had a stroke or died within 30 days after detection of the LAA thrombus. The difference in the 7-year cumulative incidence of ischemic stroke was assessed using the Gray-test. Fine-Gray proportional hazard regression was utilized to assess the impact of anticoagulation status on ischemic stroke.
Results: Among 183 patients detected with LAA thrombus, 15 suffered ischemic stroke or death within 30 days of detection, and 168 patients were included in this study. Of these, 58 patients were treated with anticoagulation therapy before the index detection of LAA thrombus (PreAC group). Patients in the PreAC group were older (median 76 years [interquartile range 51-88 years] vs. 74 years [38-89 years], P = 0.032) than those in the non-PreAC group. The rates of CHA2DS2-VASc score ≥ 2 (93% vs. 89%, P = 0.582), male sex (64% vs. 70%, P = 0.488), and history of atrial fibrillation (98% vs. 95%, P = 0.667) were similar between the two groups. The cumulative ischemic stroke rate was higher in the PreAC group than in the non-PreAC group (P = 0.048, Figure). Even after adjusting for CHA2DS2-VASc score, anticoagulation therapy before detection of LAA thrombus was significantly associated with the cumulative incidence of ischemic stroke (P = 0.049).
Conclusions: Anticoagulation status before the detection of LAA thrombus is a determinant of a higher incidence of ischemic stroke. The background mechanisms suggesting a tendency toward thrombus generation even when treated with anticoagulation are proposed.