Simple blood test 'could determine risk of potentially fatal stroke'

A simple blood test could determine the risk of a potentially fatal stroke, according to a new study.

This would enable doctors to determine whether an individual may be at a higher risk of a stroke or cognitive decline during their lifetime, scientists suggest.

The research indicates that by measuring concentrations of a network of inflammatory molecules in the blood, medics could calculate a risk score for susceptibility to cerebral small vessel disease a common cause of stroke and something that often contributes to memory issues, particularly in older people.

At present, the only method to determine a person's risk for cerebral vascular diseases involves using a combination of imaging such as an MRI scan, family history, demographic variables and other risk factor evaluations.

Dr. Jason Hinman, the lead author of the study from the University of California, Los Angeles, (UCLA) stated that in clinical practice, neurologists may discover a patient is at risk only after they've had a stroke or another medical event that warns of one.

Published in the journal Stroke, the new study found by measuring the concentrations of the network of inflammatory molecules in the blood of patients, doctors may be able to accurately determine a person's risk for cerebral small vessel disease and future stroke.

Dr Hinman said: "The same way one uses cholesterol tests to evaluate one's future risk for heart attack, we don't have such a thing to estimate future risk for stroke.

"I believe we can do that by something as simple as a blood test which in theory can enable broader access to the best level of care and not lock it behind advanced imaging studies and specialist evaluations."

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The research team honed in on a biologically-connected network of inflammatory molecules which are known as the interleukin-18, or IL-18, network, which includes proteins and signalling molecules which are vital in combating various infections.

Previous investigations have established a connection between individual molecules within the IL-18 network and the risk of cerebral small vessel disease and stroke.

However, Dr Hinman pointed out that the levels individual molecules can "fluctuate" due to other health issues such as the flu or autoimmune disorders, rendering them as inconsistent markers for stroke risk on an individual.

In 2020, a team from the University of California, which included Dr Hinman, discovered that six molecules within the IL-18 network correlated with the presence of vascular brain injuries observed in MRI scans.

Looking into this, the doctor tried to see if the IL-18 network could serve as a reliable measure for an individual's risk of experiencing a stroke or cognitive decline.

To achieve this, the research group used health data from the Framingham Heart Study, which has been recording the medical histories of numerous residents in Framingham, Massachusetts, over their lifetimes since 1948.

Blood samples taken from participants had been tested for five of the six molecules later identified as being in the IL-18 network.

Dr Hinman and his team were able to create a mathematical model that generates a risk score based on the concentrations of the IL-18 network molecules by using these blood samples and medical histories of the Framingham participants.

Of more than 2,200 Framingham residents included in Hinman’s study, those whose risk scores were in the top 25 per cent had an 84 per cent chance of having a stroke during their lifetime.

Overall, the higher risk scores were associated with a 51 per cent increased risk of stroke. Dr Hinman says that what remains unclear and requires further study is how or if a person's risk score can be modified or reduced.

He added: "The real challenge is in the primary care space. Are you at risk before you have an event? That's what we're all interested in doing is preventing a stroke before it even happens."

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