DOAC versus VKA for left ventricular thrombus after MI

ACC.25 – In the RIVAWAR trial among post-MI patients, rivaroxaban showed similar efficacy to warfarin in resolving an acute left ventricular thrombus at 3 months and a similar safety profile.

This summary is based on the presentation of Jehangir Shah, MD (Karachi, Pakistan) at the ACC.25 Scientific Session - Efficacy Of Rivaroxaban Versus Warfarin In Patients With Acute Left Ventricular Thrombus Following Myocardial Infarction: An Open-label Randomized Controlled Trial RIVAWAR Trial Investigators.

Introduction and methods

In the wake of an MI, patients may develop a left ventricular thrombus (LVT). The standard treatment are VKAs, but they have several limitations, such as the need for regular INR monitoring. Direct oral anticoagulants (DOACs) are increasingly used as an alternative. In the RIVAWAR (Rivaroxaban vs. Warfarin in Acute Left Ventricular Thrombus Following Acute Myocardial Infarction) trial, Pakistani researchers compared the efficacy and safety of rivaroxaban (DOAC) and warfarin (VKA) in post-MI patients with acute LVT.

In this single-center, investigator-initiated, open-label, noninferiority, phase 4 RCT, 261 patients with acute LVT who were diagnosed during the initial hospitalization for acute MI were randomized in a 2:1 ratio to rivaroxaban 20 mg daily or warfarin (target INR 2–3) for 3 months. The primary endpoint was LVT resolution, as assessed by echocardiography, at 3 months (noninferiority margin: 7%). Secondary endpoints included the incidence of all-cause mortality, MI, ischemic stroke, and major bleeding events at 3 months.

Main results

• At 1 month, LVT resolution was observed in 33 patients receiving rivaroxaban (n=164; 20.1%) and 7 patients on warfarin (n=84; 8.3%) (difference: 11.8%; 95%CI: 1.2–2.2; OR: 2.41; 95%CI: 1.05–2.46; P=0.017).
• There was no difference in LVT resolution at 3 months between the NOAC and VKA groups (95.8% vs. 96.6%; difference: –0.8%; 95%CI: –5.7% to 4.1%; OR: 0.98; 95%CI: 0.74–1.29; P=0.88).
• With regard to the secondary endpoints, there were no significant differences in the rates of all-cause mortality (3.5% vs. 3.3%; P>0.999), ischemic stroke (3.5% vs. 1.1%; P=0.428), and major bleeding events (2.3% vs. 1.1%; P=0.662).

Conclusion

In the single-center RIVAWAR trial among patients with post-MI LVT, rivaroxaban showed similar efficacy to warfarin in resolving LVT at 3 months, with complete resolution in >95% of the patients in both groups. There was no evidence of increased risk of mortality, ischemic stroke, or major bleeding events. Jehangir Shah concluded “these findings support rivaroxaban as a viable alternative (it is noninferior) to warfarin, offering predictable dosing and eliminating the need for routine INR monitoring in patients with post-MI LVT.”

- Our reporting is based on the information provided at the ACC.25 Scientific Session -