Biomarker Tests May Yield Earlier Heart Attack Diagnosis

Levels of the protein troponin I in patients admitted to emergency care for chest pain may help doctors rule out or confirm a diagnosis of heart attack, researchers in Germany have found.

The research team, led by Till Keller, MD, of the University Heart Center Hamburg, Germany, compared the diagnostic abilities of the recently developed highly sensitive troponin I (hsTnI) assay method of testing troponin levels with those of contemporary troponin I (cTnI) assay.

The researchers tested the two methods on 1,818 patients with suspected acute coronary syndrome who were enrolled at three different chest pain units in Germany from 2007 to 2008. They measured twelve biomarkers, including hsTnI and cTnI, upon admission, and again three hours and six hours following admission.

They found that hsTnI or cTnI levels three hours following admission may help rule out myocardial infarction. In addition, they found that a change in hsTnI or cTnI levels, utilizing the 99th percentile diagnostic cutoff value, from admission to three hours after admission could help doctors reach an early diagnosis of myocardial infarction.

"Combining the 99th percentile cutoff at admission with the serial change in troponin concentration within three hours, the positive predictive value (for ruling in AMI [acute myocardial infarction]) for hsTnI increased from 75.1 percent at admission to 95.8 percent after three hours, and for cTnl increased from 80.9 percent at admission to 96.1 percent after three hours," the researchers write, as quoted in a press release.

While the use of the new methods in combination with the 99th percentile cutoff yielded positive results, the authors noted that "the reliable detection of very low troponin concentrations using these new highly sensitive assays in the acute setting might pose a challenge in everyday clinical practice."

The sooner a heart attack can be diagnosed, the sooner patients can be administered aggressive treatment and the greater their chances of recovery.

The study was published in the December 28 issue of JAMA.