*Corresponding author: . E-mail: Behnood.bikdeli@yale.edu

BACKGROUND: The role of direct oral anticoagulants (DOACs) in the treatment of left ventricular thrombus (LVT) after ST-elevation myocardial infarction (STEMI) remains uncertain. AIMS: We aimed to compare the effect of rivaroxaban versus warfarin in patients with STEMI complicated by LVT. METHODS: Adult patients with STEMI and two-dimensional transthoracic echocardiography showing LVT were assigned to rivaroxaban (15 mg once daily) or warfarin (international normalised ratio goal of 2.0-2.5) in an open-label, randomised clinical trial (RCT). A prospective pooled analysis was planned comparing DOAC- versus warfarin-based anticoagulation for the same indication. The main outcome of the RCT was complete LVT resolution at 3 months, determined by a blinded imaging core laboratory. Complete LVT resolution and bleeding were investigated in the pooled analysis. RESULTS: A total of 50 patients (median age: 55 years, 18% females) were enrolled from June 2020 to November 2022. Three-month complete LVT resolution occurred in 19/25 (76.0%) patients assigned to rivaroxaban and 13/24 (54.2%) assigned to warfarin (relative risk [RR] 1.40, 95% confidence interval [CI]: 0.91-2.15; p=0.12) with no thrombotic or major bleeding events. Pooled analysis showed numerically better complete LVT resolution with DOACs (rivaroxaban and apixaban; 93/115 [80.8%] vs 79/112 [70.5%], RR 1.14, 95% CI: 0.98-1.32; p=0.08) and less major bleeding (2/116 [1.7%] and 9/112 [8.0%], risk difference -0.06, 95% CI: -0.12 to 0.00; p=0.05) than with warfarin. CONCLUSIONS: Although the findings are limited by a small sample size, the results suggest that DOACs are safe with at least similar outcomes concerning LVT resolution and major bleeding compared with warfarin. (ClinicalTrials. gov: NCT05705089)