[Effect of non-vitamin K antagonist oral anticoagulants on left atrial or atrial appendage thrombi in patients with nonvalvular atrial fibrillation]

Objective: To investigate the effect of non-vitamin K antagonist oral anticoagulants (NOAC) on left atrial or atrial appendage (LA/LAA) thrombi in patients with nonvalvular atrial fibrillation (NVAF). Method: Data from 3 042 patients with atrial fibrillation(AF), who underwent transesophageal echocardiography (TEE) examination before cardioversion or catheter ablation for the detection of LA/LAA thrombus in our department from March 2016 to January 2018 were prospectively analyzed. Among these patients, LA/LAA thrombus was detected by TEE in 57 patients. A total of 19 patients who received dabigatran or rivaroxaban for ≥3 weeks and underwent repeated TEE were included, 38 patients were excluded (7 patients with rheumatic heart disease, 1 patient treated with pericardial decortication, 1 patient treated with surgical repair of endocardial cushion defect, 1 patient with LA thrombus associated with the atrial septal occluder device, 14 patients received warfarin therapy, 14 patients did not receive repeated TEE). Results: First repeated TEE results showed that LA/LAA thrombus was not completely resolved in 4 out of 4 patients treated with dabigatran (110 mg bid) for a median time of 119 (47, 258) days, whereas LA/LAA thrombus was completely resolved in 5 out of 11 patients treated with dabigatran (150 mg bid) for a median time of 80 (58, 147) days. Thrombus was completely resolved in 2 out of 2 patients treated with rivaroxaban (15 mg qd) for 110 days and 95 days respectively, and in 1 out of 2 patients treated with rivaroxaban (20 mg qd) for 91 days. Second repeated TEE was performed in 8 patients. Thrombus was resolved completely in 2 out of 3 patients with undissolved thrombus treated by dabigatran (110 mg bid) after increasing the dabigatran dosage (150 mg bid). Thrombus was resolved in 3 (1 patient prolonged treatment with dabigatran 150 mg bid and 2 patients switched to rivaroxaban 20 mg qd) out of 4 patients with undissolved thrombus under the dabigatran 150 mg bid regimen, whereas the thrombus remained unresolved in 1 patient switched to rivaroxaban (15 mg qd). After receiving rivaroxaban 15 mg bid treatment, the thrombus was finally resolved in 1 patient with undissolved thrombus treated by rivaroxaban 20 mg qd. There was no clinical thromboembolism or major bleeding events during the median follow up time of 462 (305, 558) days. Conclusions: Our data show that NOAC is an effective therapeutic option for the treatment of LA/LAA thrombi. When eligible, a higher NOAC dosage may be preferred due to the higher efficacy on thrombus resolvement.