Researchers from the Uppsala University Hospital and Uppsala University in Sweden have announced a blood test that can predict the risk of stroke in individuals with atrial fibrillation, the most common cardiac arrhythmia.

The test is designed to measure the levels of neurofilament, a brain health biomarker, in the blood.

As part of a study, researchers found that higher levels of neurofilament are associated with an increased risk of stroke.

The study involved analysing neurofilament levels in blood samples from more than 3,000 patients with atrial fibrillation.

Over an average follow-up period of one and a half years, those with the highest levels of neurofilament faced a stroke risk more than triple that of individuals with the lowest levels.

Combining neurofilament levels with traditional cardiac blood tests further improved stroke prediction capabilities.

Uppsala University Hospital cardiologist and Uppsala University researcher Julia Aulin is the lead author of the study. Uppsala University Hospital stroke physician Karl Sjölin is the co-author of the study.

Sjölin said “We have not been able previously to measure the effect of atrial fibrillation on the brain in this way. Since atrial fibrillation affects both the heart and the brain, it is logical that the precision improves when both are assessed.

“We have been aware of neurofilament for a long time, but it is only in recent years that we have begun to understand how to use it.”

The research team plans to explore how different healthcare treatments impact neurofilament levels and whether this affects the risk of stroke or mortality.

Aulin said: “The findings are probably transferrable to other groups of patients with cardiovascular-related disorders, though this remains to be demonstrated. Our hope is that it will ultimately be possible to assess brain health with a simple blood test at the local health centre.”