The Safety and Efficacy of Standard-Dose versus Low-Dose Non-Vitamin K Antagonist Oral Anticoagulants in Patients with Nonvalvular Atrial Fibrillation and Left Atrial Appendage Thrombus

Abstract

Background. Data comparing different doses of non-vitamin K antagonist oral anticoagulants (NOACs) regarding resolution of left atrial appendage thrombus (LAAT) in patients with nonvalvular atrial fibrillation (AF) are scarce. This study aimed to investigate the safety and efficacy of standard-dose versus low-dose NOACs in patients with nonvalvular AF and LAAT. Methods. Patients with nonvalvular AF who underwent transesophageal echocardiography (TEE) before interventional procedures for the detection of LAAT and treated with NOACs from October 2014 to September 2020 in Ningbo First Hospital were retrospectively screened. The study population was divided into two groups according to the doses of NOACs: standard-dose group (dabigatran 150 mg, twice daily; rivaroxaban 20 mg, once daily) and low-dose group (aged ≥75 years, body weight <50 kg, or creatinine clearance <50 mL/min; dabigatran 110 mg, twice daily; rivaroxaban 15 mg, once daily). Repeated TEE was performed 1, 2, and 3 months later. The rate of LAAT completely resolved and incidence of thromboembolic and major bleeding events were compared between the two groups. Results. A total of 24 patients were included, 14 patients in the standard-dose group and 10 in the low-dose group. After 3 months, LAAT was completely resolved in 12 out of 14 (85.7%) and 8 out of 10 (80%) patients treated with standard- and low-dose NOACs, respectively. The rate of LAAT completely resolved was comparable between groups. No thromboembolic or major bleeding events occurred during the follow-up. Conclusion. Low-dose NOACs are a safe and effective option for the treatment of LAAT in some special subset patients. However, the results warrant validation in a prospective study.

Prevalence, predictors and management of left atrial appendage thrombogenic milieu in atrial fibrillation with low thromboembolic risk

“…Short-term OAC, including NOACs and VKA, has long been used to resolve LAAT or sludge in patients with NVAF. Previous studies investigating the efficacy of NOACs or AVK showed conflicting results with the resolution rate of LAAT ranging from 41.5-85.7% [14,[20][21][22][23][24]. However, in the present study, all LAATs or sludges effectively resolved after OAC medication of 3-4 months, whether standard-dose NOAC, reduceddose NOAC or VKA (TTR ranging from 60 to 75%).…”

“…Previous study demonstrated that the patients with LAAT resolution had lower CHA 2 DS 2 -VASc scores [22]. In addition, the overall resolution rate is obviously higher in the Asian race [22][23][24]. The racial disparity of effectiveness and safety with OAC has been discussed in various studies.…”