Apixaban vs Aspirin According to CHA2DS2-VASc Score in Patients With Subclinical Atrial Fibrillation

Context

Device-detected subclinical atrial fibrillation (AF) — captured by a pacemaker, defibrillator, or other implanted device — is associated with an increased risk of stroke. The randomized ARTESiA trial found that, in patients with device-detected subclinical AF, apixaban reduced the risk of stroke but increased the risk of major bleeding compared with aspirin.¹ Although roughly half of strokes in patients receiving aspirin were fatal or disabling and approximately 15% of bleeds were fatal, the contrast between efficacy and safety signals has brought about a push to identify subgroups of patients who will benefit most from apixaban. Clinical practice guidelines have previously recommended incorporating the CHA₂DS₂-VASc score into treatment decisions for this patient population.^2,3

Summary

This prespecified secondary analysis of the ARTESiA trial examined the absolute and relative rates of major bleeding according to the patient's baseline CHA₂DS₂-VASc score. Approximately one-quarter of the patients had a CHA₂DS₂-VASc score of 5 or higher. In this group, stroke rates were reduced from 2.25% per year on aspirin to 0.98% per year on apixaban, while major bleeding rates increased from 1.45% to 2.13% per year. This benefit clearly outweighed the risks. The opposite was true for approximately 40% of patients with a CHA₂DS₂-VASc score of 3 or less. In this group, stroke rates were reduced from 0.97% per year on aspirin to 0.85% per year on apixaban, while major bleeding rates increased from 1.11% to 1.44% per year. Approximately one-third of the study population, who had a CHA₂DS₂-VASc score of 4, demonstrated intermediate results. In this group, stroke rates were reduced from 0.86% per year on aspirin to 0.54% per year on apixaban, while major bleeding rates increased from 0.90% to 1.18% per year.

Take-home message

The CHA₂DS₂-VASc score is a useful tool for risk-stratifying patients with subclinical device-detected AF. Patients with a CHA₂DS₂-VASc score of 5 or higher stand to receive substantive net benefit and should be treated with apixaban. Patients with a CHA₂DS₂-VASc score of 3 or lower are unlikely to benefit and should be treated with aspirin, if clinically indicated; otherwise, they should not receive antithrombotic therapy. Patients with a CHA₂DS₂-VASc score of 4 present a challenging scenario. Although these patients seem to derive some benefit from oral anticoagulation, the final treatment decisions in this group should be based on the patient's values and preferences.

References

1. Healey JS, Lopes RD, Granger CB, et al. Apixaban for Stroke Prevention in Subclinical Atrial Fibrillation. N Engl J Med. 2024;390(2):107-117. https://www.nejm.org/doi/10.1056/NEJMoa2310234
2. Hindricks G, Potpara T, Dagres N, et al. 2020 ESC Guidelines for the Diagnosis and Management of Atrial Fibrillation Developed in Collaboration With the European Association for Cardio-Thoracic Surgery (EACTS): The Task Force for the Diagnosis and Management of Atrial Fibrillation of the European Society of Cardiology (ESC) Developed With the Special Contribution of the European Heart Rhythm Association (EHRA) of the ESC. Eur Heart J. 2021;42(5):373-498. https://academic.oup.com/eurheartj/article/42/5/373/5899003
3. Joglar JA, Chung MK, Armbruster AL, et al. 2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Atrial Fibrillation: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines. J Am Coll Cardiol. 2024;83(1):109-279. https://www.sciencedirect.com/science/article/pii/S0735109723064653?via%3Dihub