March 15 (UPI) -- A University of Alberta physician has developed a new blood test that details the extent of cardiac damage from an apparent heart attack.
The cardiac troponin blood test, which is currently used for the clinical diagnosis of myocardial infarction -- the death of heart muscle due to lack of blood supply -- doesn't reveal the extent of cardiac damage, said Peter Hwang, a clinician-scientist in the Faculty of Medicine & Dentistry at the University of Alberta. His research was published recently in the Journal of Applied Laboratory Medicine.
When cardiac troponin, a protein unique to the heart, becomes elevated in the blood, the heart has been damaged, explained Hwang.
He found that when patients have a true heart attack, they had more fragmented troponin than those with increased cardiac strain.
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"We postulated that when cells die during a heart attack, not only would they release troponin into the bloodstream, but they would also digest the troponin through the action of activated intracellular proteases -- enzymes that digest other proteins," Hwang said.
Studied were 29 inpatients from the University of Alberta Hospital and Mazankowski Heart Institute with elevated troponin levels with known heart attacks, or other conditions that increase cardiac demand.
"Sometimes the correct answer to the question -- is it a heart injury or merely strain--isn't always obvious, even with all the clinical information," Hwang said. "Suppose there is a critically ill patient with an elevated troponin level. Is the patient having a heart attack? Or is the troponin level elevated because the heart is working hard?"
A doctor needs to decide whether to send the patient for cardiac catheterization, which is an invasive procedure with some risks, or continuing their current treatment.
"This is a very real diagnostic dilemma faced by doctors treating patients. This test could resolve the challenge," he said.
