19 November 2010
A simple blood test may predict future heart disease.
A number of risk factors can predict your chance of getting a heart attack. High blood pressure or cholesterol, a history of smoking, just getting older - all of these make heart disease more likely.
When a suspected heart attack patient shows up at the hospital, doctors often test for a blood protein called cardiac troponin T, which can confirm a heart attack.
The newest versions of the test are super sensitive, measuring the protein at levels of just a few picograms - trillionths of a gram - per milliliter of blood.
"And this is allowing us to identify evidence of heart injury - troponin protein is released when heart cells die - in individuals who are seemingly without any obvious cardiovascular disease, whether it be chest pain and heart attacks, or whether it even be symptoms of heart failure," says University of Maryland medical professor Christopher deFilippi.
DeFilippi and his colleagues tested troponin levels in blood samples taken years ago from a group of almost 6,000 older Americans. Then, the researchers compared troponin levels with the health of the individuals as they aged. They found that higher levels of troponin correlated to a higher likelihood of heart failure, which is when the heart's pumping ability declines.
"So it could both identify individuals who were at the highest risk for developing the signs and symptoms of a failing heart, and also individuals who were at the highest risk of dying of heart disease."
DeFilippi says the troponin test turns out to be a strong predictor by itself of heart failure or of death from any kind of heart disease, and it does so independent of other risk factors.
"It is, as a blood test, similar to cholesterol, a measure of a continuum of values, so it's not a yes/no answer, but you're able to stratify people into very low risk, low risk, intermediate, [and] high risk for these events based upon the [troponin] number."
Christopher deFilippi says the test should be relatively affordable since the chemicals used to process each sample, only cost a dollar or so. And patients who learn they are on the path to heart failure can work with their doctor to minimize progression of the disease.
DeFilippi's paper describing his research is published online by the journal of the American Medical Association, JAMA.