A highly sensitive version of a blood test used in hospital emergency rooms to confirm whether someone is having a heart attack can also detect heart disease in seemingly healthy people. Researchers say the test could become part of a routine health check-up.
The test has been used in hospital emergency rooms for the past 15 years to check for cardiac troponin T, or cTnT, a protein associated with cardiac injury following a heart attack.
The protein is elevated in about one percent of people who show no symptoms of heart disease.
But in a study of a newer, highly sensitive version of the cTnT test, researchers led by James de Lemos of the University of Texas Southwestern Medical Center in Dallas, Texas, found they could detect the protein in about 25 percent of seemingly healthy individuals.
"And it really correlates very strongly with unrecognized structural heart disease, meaning thickening or weakening of the heart muscle and with death over a long term follow up, suggesting that it might offer some real power for predicting heart disease in the office rather than in the emergency room," said de Lemos.
In the so-called Dallas Heart Study, which involved 3,500 individuals, investigators found that people with detectable levels of cTnT were seven times more likely to die of heart disease within six years.
Researchers also discovered the standard blood test failed to detected elevated cTnT in two-thirds of people with the highest protein levels.
Men were three times more likely than women to have detectable levels of the protein. Also, more than 57 percent of individuals in their 60's had detectable cTnT compared to 14 percent of participants in their 40's and 50's.
De Lemos says the test is relatively inexpensive and the hope is that it could be used to identify people at risk for heart disease before they have symptoms so that they can take steps to improve survival with medications and lifestyle changes.
"This is a sort of slow burn kind of injury we think we are seeing, not heart attacks," he said. "These are slow chronic injuries. And what we would like to do is turn that injury off and that will preserve the heart muscle as a pump and prevent the development of heart failure and death we think."
Two studies investigating use of the cardiac troponin T test to identify people at risk for heart disease are published this week in the Journal of the American Medical Association.