Rivaroxaban vs Warfarin in Acute Left Ventricular Thrombus Following Myocardial Infarction: RIVAWAR, An Open-Label RCT.

BACKGROUND

Vitamin K antagonists, such as warfarin, are the standard treatment for left ventricular thrombus (LVT). However, direct oral anticoagulants, such as rivaroxaban, are increasingly being considered due to their fixed dosing and lack of routine monitoring requirements.

OBJECTIVES

This study aimed to compare the effectiveness of rivaroxaban vs warfarin in treating post-myocardial infarction (MI) acute LVT at 12 weeks.

METHODS

We conducted an open-label, noninferiority, randomized controlled trial involving patients with acute LVT diagnosed during initial MI hospitalization. Participants were randomized 2:1 to receive either rivaroxaban (20 mg daily) or warfarin (target international normalized ratio 2-3) for 12 weeks. The primary endpoint, LVT resolution, was assessed by echocardiography at 4 and 12 weeks.

RESULTS

A total of 261 patients were randomized, with 171 in the rivaroxaban group and 90 in the warfarin group. The groups were similar in sex, age, and MI subtype, with most having ST-segment elevation MI and severe LV dysfunction. At 4 weeks, LVT resolution was higher in the rivaroxaban group (20% vs 8%; P = 0.017), with similar resolution at 12 weeks (95.8% vs 96.6%; P = 0.759). The cumulative all-cause mortality was comparable (3.5% vs 3.3%; P = 0.921). Major bleeding occurred in 2.3% of rivaroxaban patients vs 1.1% of the warfarin group (P = 0.491).

CONCLUSIONS

Rivaroxaban demonstrated similar efficacy to warfarin in treating post-MI LVT, with >95% resolution in both groups. Future multicenter trials with longer follow-up are needed to validate these findings (Rivaroxaban in Left Ventricular Thrombus; NCT04970576).