Comparative effectiveness of different management strategies for left atrial appendage thrombus in patients on optimal NOAC therapy

Abstract

Abstract Background Left atrial appendage (LAA) thrombus is the primary cause of stroke and systemic embolism in atrial fibrillation (AF). Novel oral anticoagulants (NOACs) effectively reduce the prevalence of LAA thrombosis and stroke risk. Nonetheless, there is no clear advice for patients with a NOAC-resistant thrombus, necessitating individualized decision-making without strong support of the current guidelines. Aims To analyze patients diagnosed with an LAA thrombus despite adequate NOAC therapy and to compare the efficacy of various therapeutic strategies in achieving thrombus resolution. Methods We retrospectively analyzed patients scheduled for cardioversion or catheter ablation of AF between 2014 and 2023 who were diagnosed with LAA thrombus despite being on optimal NOAC therapy. These patients underwent follow-up transesophageal echocardiography (TEE) or cardiac CT angiography. Changes in treatment modalities were divided into four groups: transition to an alternative NOAC, switch to a vitamin K antagonist (VKA), the addition of an antiplatelet agent, or the deliberate maintenance of the current treatment. Results We analyzed the data of 90 patients comprising 103 cycles of treatment. The patients were either on rivaroxaban (41%), apixaban (32%), dabigatran (15%) or on edoxaban (12%) at the time of the initial TEE. A change to a different NOAC was observed in 37% of cases, transition to a VKA in 22%, supplementation with antiplatelet therapy in 16%, while deliberate absence of treatment modification in 25% of cases. Subsequent follow-up TEE (or CT angiography in a minority of cases) was performed at a median of 68 [43 – 94] days from the baseline evaluation. Successful thrombus resolution was achieved in 72% of cases. Evaluation of therapeutic strategies revealed that any modification of treatment was three times more effective than deliberate no change in treatment; thrombus resolution was observed in 60 (81%) vs. 17 (59%) cases (OR 3.03 [1.18 - 7.75], p = 0.021). Nevertheless, no particular strategy demonstrated superior efficacy over others. Conclusions Resolution of LAA thrombus in patients already on adequate NOAC treatment may require a revision of the prior anticoagulation strategy; however, none of the commonly employed strategies appears to exhibit distinct superiority over the rest.