The association of anticoagulation therapy characteristics with left atrial thrombus lysis in patients with nonvalvular persistent atrial fibrillation

Abstract

Purpose. The aim of this study was to reveal the effect of the duration and characteristics of anticoagulant therapy on the clot dissolution in the left atrial appendage (LAA) in patients with persistent atrial fibrillation (AF).Material and methods. The repeat transesophageal echocardiography was performed in 68 patients with persistent AF, because the thrombus was detected in the LAA during the first examination. Of these, 37 (54.4%) patients started or continued to receive warfarin and 31 (45.6%) patients continued to receive the direct oral anticoagulants. Transesophageal echocardiography was repeated after 3-5 weeks. One follow-up examination was for 53 patients, two follow-up examination was for 11 patients and three follow-up examination was for 4 patients. Cox regression analysis was performed to identify factors affecting the likelihood of clot dissolution and Kaplan-Meier survival analyses with log-rank tests were used to compare the clot dissolution time.Results. The chance of the LAA thrombus lysis is 50% after 35.0 ± 3.7 days of receiving anticoagulants. This time is reduced to 30.0 ± 1.4 days for small thrombus (no more than 18 mm), and it increases to 45.0 ± 7.4 days (p = 0.038) for large thrombus. The dissolution time of small thrombus depends on the characteristics of the treatment: the median of the dissolution curve is 24.0 ± 3.7 days when the patients received the direct oral anticoagulants, and the median of the dissolution curve is 40.0 ± 7.2 days (p = 0.009), if the patients received warfarin. The dependence of the dissolution time of large thrombus on the characteristics of treatment did not found.Conclusion. The LAA thrombus dissolution time in patients with atrial fibrillation depends on their size, and the dissolution time of small thrombi depends on the characteristics of anticoagulant therapy.