According to The Heart Foundation, more than 920,000 Americans will suffer a heart attack this year, and many of these will occur without warning. But researchers from The Scripps Research Institute in California say they have created a blood test which may be able to predict whether patients are at high risk of heart attack.
The research team, led by Prof. Pete Kuhn, says that at present there is no test available that can predict the occurrence of a heart attack with good accuracy.
But they say their novel test, details of which have been recently published in the journal Physical Biology, has so far proved successful in identifying which patients are undergoing treatment for a recent heart attack and which patients are healthy.
Test identifies endothelial cells in blood
The new test uses a "fluid biopsy" technique. It works by identifying the presence of endothelial cells - which line the artery walls - in the bloodstream.
According to the researchers, endothelial cells that circulate in the bloodstream have been associated with ongoing heart attacks.
Lady suffering chest pain
Researchers say the HD-CEC test can accurately detect circulating endothelial cells in patients, meaning the test could be used to predict heart attack risk.
They believe that endothelial cells enter the bloodstream as a result of diseased plaque building up, rupturing and ulcerating in the arteries, which triggers inflammation.
They add that this damage to the arteries can lead to the formation of blood clots. This stops the blood flowing through the arteries, which in turn can cause a heart attack.
Using a newly-created procedure called the High-Definition Circulating Endothelial Cell (HD-CEC) assay, the researchers were able to identify and differentiate endothelial cells in blood samples of 79 patients, all of whom had already suffered a heart attack when their samples were taken.
The researchers also used the HD-CEC assay on two groups of patients as a control measure. One group was made up of seven patients who were receiving treatment for cardiovascular disease, while the other group consisted of 25 healthy patients.
Blood test 'successfully identified heart attack patients'
The research team found that the HD-CEC assay was able to detect circulating endothelial cells in the blood of the patients through the cells' "morphological features and their reactions with specific antibodies."
Patients who suffered a heart attack had much higher levels of circulating endothelial cells in their blood, compared with healthy patients. And the researchers note that the cells were identified with "high sensitivity and high specificity."
To further confirm the accuracy of the HD-CEC assay, the researchers compared it with CellSearch - a test that has been approved by the US Food and Drug Administration (FDA) to identify circulating tumor cells in patients with cancer.
From this, the investigators found that the HD-CEC test was able to detect circulating endothelial cells more accurately than the CellSearch test.
The researchers say this is because the HD-CEC test "used a direct analysis method and was free of bias from an enrichment stage."
"Our assay effectively analyzes millions of cells, which is more work but guarantees that you are analyzing all of the potential cells," says Prof. Kuhn.
The investigators believe the technique is now ready to be tested on patients who show symptoms of increased risk of heart attack, but have not yet suffered one.