Apixaban reduces the risk of stroke in device-detected subclinical atrial fibrillation

By Dr. Florence Mouy
Edited by Dr. Ahmed El-Medany

The ARTESIA trial (Apixaban for the Reduction of Thrombo-Embolism in Patients with Device-Detected Sub-Clinical Atrial Fibrillation) has shown that apixaban reduces the risk of stroke in patients with device-detected subclinical atrial fibrillation (AF) who have risk factors for stroke.

Subclinical AF has been shown to increase the risk of stroke by a factor of 2.5 in patients with risk factors for stroke. This is lower than in patients with clinical AF (4-5-fold increased risk of stroke), and therefore the role of oral anticoagulation in this situation was unclear.

The investigators conducted a double blind, double dummy randomised controlled trial of 4,012 patients with device-detected episodes of AF lasting between 6 minutes to 24 hours, with CHA₂DS₂-VASc scores of ≥3. Patients were randomised either to apixaban 5mg twice daily (reduced dose of 2.5mg twice daily when indicated) or aspirin 81mg daily. If AF lasted over 24 hours or if clinical AF developed, the trial medication was stopped, and anticoagulation commenced.

After a mean follow-up period of 3.5±1.8 years, the primary efficacy outcome of stroke or systemic embolism occurred in 55 patients in the apixaban group (0.78% per patient-year) and 86 patients in the aspirin group (1.24% per patient-year), using intention to treat analysis (hazard ratio, 0.63; 95% confidence interval [CI], 0.45 to 0.88; P=0.007). In the on-treatment population, the rate of major bleeding was 1.71% per patient-year in the apixaban group and 0.94% per patient-year in the aspirin group (hazard ratio, 1.80; 95% CI, 1.26 to 2.57; P=0.001). Fatal bleeding occurred in 5 patients in the apixaban group and 8 patients in the aspirin group.

These results demonstrate that apixaban reduces the risk of stroke in subclinical AF but increases the risk of major bleeding, as compared with aspirin. Fewer fatal bleeding episodes occurred in the apixaban group. Given the long-term sequelae of stroke, clinicians should consider prescribing oral anticoagulation to patients with subclinical AF and risk factors for stroke.