The following is a summary of “Apixaban for Stroke Prevention in Subclinical Atrial Fibrillation,” published in the January 2024 issue of Neurology by Healey et al.

Researchers performed a retrospective study investigating the effectiveness of oral anticoagulation against the 2.5-fold stroke risk associated with subclinical atrial fibrillation.

They conducted a trial with patients experiencing subclinical atrial fibrillation lasting 6 to 24 hours. Patients were randomly selected in a double-blind, double-dummy design to receive 5 mg of apixaban twice daily (2.5 mg twice daily when indicated) or 81 mg of aspirin daily. If atrial fibrillation lasted more than 24 hours or clinical atrial fibrillation occurred, trial medication was halted, and anticoagulation began. In the intention-to-treat group, the primary focus was on assessing stroke or systemic embolism in all randomized patients. Examining on-treatment patients for major bleeding, follow-up was censored 5 days after permanent trial medication discontinuation.

The results showed 4,012 patients, with a mean age of 76.8±7.6 years mean CHA2DS2-VASc score of 3.9±1.1 (0 to 9 range, higher scores indicating greater stroke risk); 36.1% were women. After 3.5±1.8 years follow-up, the apixaban group had 55 strokes or systemic embolisms (0.78% per patient-year) vs. the aspirin group with 86 events (1.24% per patient-year) (HR, 0.63; 95% CI, 0.45 to 0.88; P=0.007). In the on-treatment population, the major bleeding rate was 1.71% per patient-year with apixaban and 0.94% with aspirin (HR, 1.80; 95% CI, 1.26 to 2.57; P=0.001). Fatal bleeding occurred in 5 patients with apixaban and 8 with aspirin.

They concluded that apixaban topped aspirin in subclinical AF stroke prevention but bled more, tilting the decision towards individualized risk-benefit assessment.

Source: nejm.org/doi/full/10.1056/NEJMoa2310234