ARTESiA Trial results were presented at the American Heart Association Scientific Sessions 2023

Examining stroke prevention and bleeding risk in subclinical atrial fibrillation, including the NOAH-AFNET 6 Trial

November 27, 2023

  • Summary: ARTESiA Late-Breaking Clinical Trial presented at AHA showed that apixaban was better than aspirin at preventing strokes in device-detected subclinical afib lasting 6 minutes to 24 hours.
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This month, the results from the ARTESiA Trial (Apixaban for the Reduction of Thrombo-Embolism in Patients With Device-Detected Sub-Clinical Atrial Fibrillation) were presented at the Afib Late-Breaking Clinical Trials session at the American Heart Association Scientific Sessions in Philadelphia. These results were presented by Dr. Jeff Healey, principal investigator.

While the news stories gave the headline to apixaban (Eliquis) for preventing strokes, those of us who follow this space closely were watching for the results of ARTESiA to tell us something about how device-detected subclinical afib (SCAF) should be treated. Questions vexing doctors for years have been whether anticoagulants should be given when afib is found incidentally on an implanted device and how much afib there needs to be for anticoagulants to be necessary. We had long been anticipating getting some answers from the NOAH and ARTESiA Trials this year.

When ARTESiA was designed, aspirin was still being used in overall afib stroke prevention, but anticoagulants were becoming predominant. However, we didn’t know how subclinical afib should be treated. The plan was to randomize 4000 patients from 240 sites in Canada, the US, and Europe to apixaban or aspirin to answer this question. The trial involved patients with device-detected subclinical afib of six minutes to 24 hours.

Study results showed that apixaban was better at preventing stroke and systemic embolism (clots) than aspirin in subclinical afib. However, it did show that there was a higher risk of major bleeding with apixaban. 

The trial was published in The New England Journal of Medicine simultaneously with the presentation at AHA.

What About the Results From NOAH-AFNET 6?

A new substudy of the NOAH-AFNET 6 Trial was also presented during the Afib Late-Breaking Clinical Trials session at AHA.

In August, the NOAH-AFNET 6 Trial of stroke prevention in subclinical afib using edoxaban (Savaysa) was presented at the European Society of Cardiology in Amsterdam. It showed that for patients 65 or over with six minutes or more of device-detected subclinical afib and one or more additional stroke risk factors, anticoagulants (blood thinners) cause bleeding without preventing strokes. Again, this is for those without ECG-diagnosed afib but strictly afib detected on an implantable device.

The substudy presented at AHA addressed just the subclinical afib that was 24 hours or longer. There were few strokes in the overall study, and looking at those with 24 hours or more didn’t change the results.

However, an important study finding was that patients with device-detected subclinical afib of 24 hours or more were more likely to go on to develop afib that could be detected on an ECG. One potential way to view this is that once there is a higher burden of afib, it is more likely to be detected on an ECG and more likely to result in a clot or stroke. Within the study, nearly one-fifth of participants were eventually diagnosed with afib.

NOAH-AFNET 6 seems to present a contradiction with ARTESiA. However, the principal investigators of both did a meta-analysis across both studies. They found that there was not a contradiction. Those results were published in Circulation concurrently with the late-breaking presentations of both studies at AHA. They found that the results of these two trials are consistent and provided evidence that in those with device-detected subclinical afib, treatment with edoxaban or apixaban reduces stroke risk and increases the risk of major bleeding.

To learn more about ARTESiA, NOAH-AFNET 6, and the meta-analysis of those two trials, see: