Apixaban is not inferior to warfarin for resolution of left ventricular thrombus (LVT) after an acute or recent myocardial infarction (MI) according to study findings published in CJC Open.
The open-label, randomized controlled study compared the efficacy and safety of apixaban with warfarin for the resolution of post-MI LVT in contemporary practice. Participants were aged 18 to 80 years with a history of acute (within 1 week) or recent (within 1 month) anterior wall MI, with evident LVT on conventional transthoracic echocardiography.
The patients were assigned to apixaban (5 mg twice daily) or dose-adjusted warfarin to achieve a target international normalized ratio (INR) of 2.0 to 3.0 for the study duration. Clinical assessment was conducted at enrollment and at 1, 3, and 6 months.
LVT resolution at 3 months was the primary endpoint. To achieve noninferiority, apixaban had to have 95% or more LVT resolution vs warfarin.
A total of 50 patients with post-MI LVT were included and completed the follow-up, with the first patient randomized in September 2018 and the last patient completing follow-up in July 2021. Of the cohort, 25 participants received apixaban (mean age, 52±8.2 years), and 25 received warfarin (mean age, 53±7.9 years).
No patients had a stroke, transient ischemic attack or other systemic embolisms, new MI, death from any cause, unscheduled hospitalization, or clinical evidence of bleeding. At 3 months, hemoglobin level was confirmed in 20 patients (80.0%) in the apixaban group and in 19 participants (76.0%) in the warfarin group (13.3±2.6 vs 13.2±2.5 gm/dL, respectively). The warfarin group had an INR time within the time-in-therapeutic range of 73%.
Apixaban was noninferior to warfarin for LVT resolution, with no statistical difference occurring in resolution rates. At 1 month, 10 patients (40.0%) who received apixaban had LVT resolution, 13 (52.0%) had LVT regression, and 2 had persistent LVT. At 1 month in the warfarin group, 14 patients (56.0%) had LVT resolution, 10 (40.0%) had LVT regression, and 1 had persistent LVT.
At 3 months, 19 patients (76.0%) who received apixaban had LVT resolution, 5 (20.0%) had LVT regression, and 1 had persistent LVT. In the warfarin group, 20 participants (80%) had LVT resolution, and 5 (20.0%) had LVT regression. Apixaban was associated with 95% relative success in LVT resolution at 3 months vs warfarin (P <.036 for noninferiority).
At 6 months, 23 participants (92.0%) in the apixaban group and 24 (96.0%) in the warfarin group had complete LVT resolution. No patients who had the oral anticoagulant stopped after LVT resolution at 3 months had echocardiographic recurrence at 6 months.
According to multivariate adjustment analysis, an LV aneurysm (hazard ratio [HR], 1.65; 95% CI, 1.03-1.87; P <.024), a larger baseline LV thrombus area (HR, 1.63; 95% CI, 1.32-2.74; P <.031), and lower LVEF (HR, 1.39; 95% CI, 1.02-2.54; P <.043) were independent predictors of LVT persistence at 3 months.
Study limitations include the nonblinded design, small sample size, and use of echocardiography for LVT detection. Also, the findings cannot be generalized to older and sicker patients and are not powered to assess the clinical outcome.
“Our study provides additional evidence, as a small randomized controlled clinical trial, of the benefit of direct oral anticoagulants in patients with LVT after acute or recent MI,” the investigators wrote.
Youssef AA, Alrefae MA, Khalil HH, et al; on behalf of the Canadian Cardiovascular Society. Apixaban in patients with post-myocardial infarction left ventricular thrombus: a randomized clinical trial. CJC Open. Published online December 9, 2022. doi: https:// doi.org/10.1016/j.cjco.2022.12.003