Atrial fibrillation (AF) is a common cardiac arrhythmia characterized by irregular and rapid heart rates, which may lead to various complications, such as stroke, heart failure, and thrombus formation. One particular complication, the development of a left atrial appendage thrombus, increases the risk of thromboembolic events, posing significant health risks to affected individuals. Patients with atrial fibrillation with a left atrial appendage thrombus should receive oral anticoagulation with a non-vitamin K antagonist oral anticoagulant (NOAC), such as rivaroxaban in a standard dose of 15 mg or 20 mg, according to creatinine clearance. However, these guidelines do not provide clear instructions on managing patients with a left atrial appendage thrombus who have already been anticoagulated with 20 mg rivaroxaban for 21 days without thrombus resolution prior to cardioversion. In light of this, we attempted an off-label treatment approach by administering a double dose of rivaroxaban (15 mg twice daily) to a patient presenting with AF and a persistent left atrial appendage thrombus. This case report explores this innovative off-label treatment approach, emphasizing the importance of effective management strategies to mitigate the associated complications and improve patient outcomes. This case report describes a patient with atrial fibrillation and a left atrial appendage thrombus who underwent successful cardioversion after receiving 15 mg of rivaroxaban twice daily as an off-label treatment. The patient well tolerated the increased frequency of administration. This case report suggests that using 15 mg of rivaroxaban twice daily for 14-21 days as an off-label treatment may be viable for patients with atrial fibrillation and a persistent left atrial appendage thrombus despite standard anticoagulation therapy. Clinicians should consider this approach when developing treatment plans for these patients, especially when traditional management strategies have proven ineffective and while keeping in mind the findings of the X-VERT study.

DOI: 10.52340/GBMN.2023.01.01.33

BACKGROUND

Atrial fibrillation (AF) is a prevalent cardiac arrhythmia affecting approximately 1-2% of the general population. It is associated with significant morbidity and mortality, primarily due to the increased risk of stroke and other thromboembolic events. Current treatment strategies for AF patients focus on reducing this risk, with direct oral anticoagulants (DOACs) such as rivaroxaban emerging as effective therapeutic options for managing AF. Specifically, a standard dose of Rivaroxaban 15 mg or 20 mg according to the Creatinine clearance regimen has been widely adopted for stroke prevention in AF patients before cardioversion. Numerous clinical trials, such as the ROCKET AF (1) and X-VeRT (2) studies, have demonstrated the efficacy and safety of rivaroxaban in AF patients. In the ROCKET AF trial, (1) rivaroxaban displayed noninferiority to warfarin, with a 21% relative risk reduction in stroke or systemic embolism. The X-VeRT trial (2) further supported the use of rivaroxaban in patients undergoing cardioversion, showcasing a 2.1% event rate for rivaroxaban-treated patients compared to a 2.0% event rate for those on vitamin K antagonists. In cases where a left atrial appendage thrombus is present before cardioversion, guidelines recommend adequate anticoagulation therapy. However, they do not specifically address the management of patients whose thrombus does not resolve after receiving the standard 20 mg once-daily rivaroxaban regimen for three weeks. This case report examines the potential benefits of an alternative rivaroxaban dosing regimen for a patient with atrial fibrillation and left atrial appendage thrombus before cardioversion. This experimental approach involves administering 15 mg of rivaroxaban twice daily for three weeks, a regimen used in the EINSTEIN study (3) for treating pulmonary embolism (PE). The EINSTEIN study (3) demonstrated the efficacy and safety of rivaroxaban in patients with PE, showing a 2.1% recurrence rate for rivaroxaban-treated patients compared to a 1.8% rate for those on standard anticoagulation therapy (noninferiority p<0.001). Building upon the established efficacy of the 20 mg once-daily treatment and the success of the EINSTEIN study, we explore the potential of the 15 mg twice-daily rivaroxaban regimen as a practical approach for managing left atrial appendage thrombus in patients with atrial fibrillation who are undergoing cardioversion. Further research is needed to assess the safety and efficacy of this alternative dosing regimen in this specific patient population.

CASE