A subgroup analysis from the ARTESiA trial suggests that the CHA₂DS₂-VASc score can help with risk stratification.

Several recent trials examine the benefits and risks of anticoagulation for atrial high-rate episodes (also known as silent atrial fibrillation [AF]; NEJM JW Cardiol Aug 30 2023 and N Engl J Med 2023; 389: 1167-1179; NEJM JW Cardiol Nov 13 2023 and N Engl J Med 2024; 390: 107-117). Anticoagulation appears to prevent ischaemic events, but these events are infrequent and largely offset by bleeding risk, resulting in limited net gain for patients.

To identify subgroups who may benefit from anticoagulation, researchers analysed data from the double-blind ARTESiA trial involving 4012 patients with silent AF who were randomised to apixaban (5 mg twice daily) versus aspirin (81 mg once daily). Results were stratified by the CHA₂DS₂-VASc score.

Among those with a CHA₂DS₂-VASc score above 4 (27%), apixaban resulted in 1.28 fewer episodes of stroke or systemic embolism per 100 patient- years of follow up without a significant increase in bleeding risk. In patients with a CHA₂DS₂-VASc score of 4 (34%) or below 4 (39%), the reduction in stroke or systemic embolism was not statistically significant.

Comment: These results are a useful complement to the main results of the ARTESiA and NOAH-AFNET 6 trials. The widely known CHA₂DS₂-VASc score seems to be a simple discriminator for shared decision-making about anticoagulation in patients with silent AF. Considering that the bleeding risk in this population is small but cumulative over time, it may be reasonable to forego anticoagulation in those with silent AF and a low CHA₂DS₂-VASc score (below 4). As we get more accurate with precision medicine, I wonder if incorporation of other factors, such as history of rheumatic heart disease, inflammatory conditions and left atrial size, may also help us further refine risk stratification. 

Note to readers: At the time we reviewed this paper, its publisher noted that it was not in final form and that subsequent changes might be made.

Behnood Bikdeli, MD, MS, Associate Physician, Division of Cardiovascular Medicine, Brigham and Women’s Hospital, Boston; Instructor in Medicine, Harvard Medical School, Boston; Investigator, Yale New Haven Hospital Center for Outcomes Research and Evaluation, New Haven, USA.

Lopes RD, et al. Apixaban versus aspirin according to CHA₂DS₂-VASc score in subclinical atrial fibrillation: Insights from ARTESiA. J Am Coll Cardiol 2024 May 19; e-pub (https://doi.org/10.1016/j. jacc.2024.05.002).

This summary is taken from the following Journal Watch title: Cardiology.