Blood Test May Detect Heart Damage Years Before Symptoms Appear
Test May Soon Help Doctors Spot Early Heart Failure
Many Middle-aged Adults Test Positive for a Marker of Heart Damage continued...
When researchers analyzed the results, they found that 25% of participants had detectable troponin T levels at the beginning of the study.
Perhaps more surprising, however, was that when they narrowed their results to people without medical conditions known to contribute to heart disease, like diabetes, high blood pressure, or chronic kidney disease, 1 in 6 still had detectable levels of the protein.
And the higher a person’s level, the greater their risk of dying, even if they had no other known risk factors. About 2% of the group with the lowest troponin T levels died during the study compared to 28% of the group with the highest levels.
But de Lemos says troponin testing is likely to complement, rather than replace, other kinds of heart checks because the protein seems to be picking up a “different family of risk.”
“This looks like not a marker of heart attacks in the sense of myocardial infarction, which is a problem of atherosclerosis or thrombosis, but rather a marker of heart failure, which is typically problems with either weakening or thickening of the heart,” he says.
“These are changes in the heart muscle before people develop frank heart failure. It’s reading early heart damage caused not by heart attacks but by chronic stress on the heart, be it from hypertension or kidney disease, or other factors,” de Lemos adds.
Lowering Troponin T Levels May Lower Heart Risks
In the second study, of more than 4,000 adults over age 65, two-thirds had detectable levels of troponin T on the highly sensitive test, even though they had no history of heart failure.
“There are very low levels of troponin in seemingly normal people,” says study author Christopher R. deFilippi, MD, a cardiologist and associate professor at the University of Maryland School of Medicine in Baltimore. “That’s the scary thing about this scenario. Our study participants were older, but they had none of the traditional risk factors.”
And as in the previous study, deFilippi and his team found that the higher a person’s troponin T level, the greater their risk of developing heart failure or dying from heart disease.
Over an average follow-up of about 12 years, people with the highest levels had a fourfold greater risk of developing heart failure and a threefold greater risk of dying of cardiovascular problems, compared to those with undetectable levels.
In contrast to the previous study, deFilippi and his team repeated the troponin T test every two to three years, so they were able to see how study participants fared if their levels changed over time. Those whose levels were detectable at the beginning and increased by 50% or more had about a 60% increased risk of developing heart failure or dying compared with those whose levels remained stable.