Heart attacks are frightening mostly because they are so unexpected; they can happen at anytime, anywhere and can have long-term health consequences. And while doctors have a range of tests that can predict who is at highest risk of having an event in the immediate future, these measures are not always sensitive and can be very invasive.
So a group of experts in the PREDICT trial (Personalized Risk Evaluation and Diagnosis in the Coronary Tree) decided to look at something easily accessible, like blood, for some predictive factors. The idea was to find an alternative to the angiogram, in which technicians snake a long catheter outfitted with a camera from the large leg artery into the heart to view blockages. The angiogram is the gold standard for documenting obstructed arteries that can narrow enough to prompt a heart attack, but the procedure requires an overnight stay in the hospital and can irritate vessels and dislodge clots that may occlude blood flow as well. (More on Time.com: Don’t Choke: 5 Tips for Performing Under Pressure)
When the group tested a panel of 23 genes that make products detectable in the blood, they found that the screen was 83% sensitive in picking up the obstructions typical of coronary artery disease. Using the genetic test on top of a risk assessment that included clinical factors such as type of chest pain improved the doctors’ ability to predict which patients were high or low risk by 16%. The gene test correctly re-categorized twice as many patients as being high or low risk than it incorrectly placed in these groups.
But those results, published in the Annals of Internal Medicine, are not enough to replace the angiogram quite yet, say some. “The whole concept of using genetic and protein risk prediction is a very important future-oriented strategy,” says Dr. Ralph Sacco, president of the American Heart Association. “But I don’t think in this case the test is ready yet for prime time.” (More on Time.com: The ‘Other’ Salt: 5 Foods Rich in Potassium)
Sacco notes that the improvement in predicting which patients were at high or low risk of having coronary artery disease was still relatively small, and that while the greatest benefit was found among patients considered at intermediate risk, “we don’t know how valid that reclassification is.”
He also points out that other than angiograms, doctors can use less invasive tests such as a stress test that measures how the heart responds under pressure, such as during exercise, and taking a CT of heart vessels to check how well blood is flowing. “This opens up the intriguing idea that we can use genetic risk markers to better risk stratify people,” he says. “But they may be of more value in the future.”
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