Apixaban versus Aspirin for Embolic Stroke of Undetermined Source

Area of Science:

• Neurology
• Cardiology
• Clinical Trials

Background:

• Previous trials showed rivaroxaban and dabigatran were not superior to aspirin for embolic stroke of undetermined source (ESUS).
• The efficacy of apixaban compared to aspirin in ESUS patients with cardioembolic risk factors remained unknown.

Purpose of the Study:

• To evaluate if apixaban is superior to aspirin in preventing new ischemic lesions in ESUS patients with identified risk factors for cardioembolism.
• To compare rates of ischemic lesions and bleeding events between apixaban and aspirin treatments.

Main Methods:

• A multicenter, randomized, open-label trial comparing apixaban (5 mg twice daily) with aspirin (100 mg once daily) in ESUS patients.
• Patients had at least one risk factor for atrial fibrillation or patent foramen ovale; cardiac monitoring was mandatory.
• The primary outcome was new ischemic lesions on brain MRI at 12-month follow-up.

Main Results:

• Apixaban was not superior to aspirin; new ischemic lesions occurred in 13.6% of the apixaban group versus 16.0% of the aspirin group (aOR 0.79; 95% CI 0.42-1.48).
• Bleeding rates were similar between groups (cumulative incidences 2.9% for apixaban vs. 4.2% for aspirin).
• The trial was terminated early due to futility based on an interim analysis.

Conclusions:

• Apixaban treatment demonstrated no superiority over cardiac monitoring-guided aspirin in preventing new ischemic lesions in an enriched ESUS population.
• The findings suggest that current anticoagulants may not offer additional benefits over aspirin in specific ESUS patient subgroups.
• Further research may be needed to identify optimal antithrombotic strategies for ESUS patients with specific risk factors.