Apixaban versus Warfarin in Patients with Left Ventricular Thrombus: A Pilot Prospective Randomized Outcome Blinded Study Investigating Size Reduction or Resolution of Left Ventricular Thrombus

Background: Treatment of the left ventricular thrombus (LVT) with Vitamin K antagonists (VKAs) such as warfarin may lead to longer hospitalization. Thus, the potential of non-VKA oral anticoagulants as alternative to warfarin need to be explored. This study aims to investigate the size reduction or resolution of LVT with apixaban compared to conventional warfarin. Materials and Methods: This is a pilot, prospective, single-center, randomized, single-blinded outcome study with patients diagnosed with LVT. Patients diagnosed with LVT by echocardiography were randomized into two treatment groups: apixaban or warfarin, with target international normalized ratio 2–3. Echocardiography was repeated at weeks 6 and 12 to assess the LVT size. The percentage of reduction or total resolution during the first 12 weeks was the primary endpoint. Repeated measure ANCOVA was used to evaluate the differences in left ventricular (LV) thrombus size between treatment groups. Results: Twenty-seven patients were recruited: 14 were treated with apixaban and 13 patients with warfarin. Thirteen patients completed treatment in the apixaban arm with one patient lost to follow-up, and one death observed. In the warfarin arm, nine patients completed the study follow-up, and four died during the follow-up. The mean (standard deviation [SD]) reduction in LV thrombus size in apixaban arm was 65.1% (SD 31.3) versus warfarin arm, 61.5% (SD 44.0) at the 12th week follow-up (P = 0.816). Safety outcomes were similar with both treatment arms. Conclusions: This pilot study suggests that apixaban may have similar effectiveness and safety to warfarin for LVT resolution.