Speeding Up Heart Attack Diagnosis

Biomarker tests diagnoses heart attack

(RxWiki News) Heart attack treatment can be tricky because diagnosing it may require numerous tests for an actual confirmation. A more sensitive diagnostic biomarker test could immediately rule out a heart attack.

Researchers have found that three hours after a hospital admission, changes in the patient's levels of highly sensitive troponin, a protein in muscle tissue, also could confirm a diagnosis of heart attack.

"Go to the hospital immediately if you have chest pain."

Dr. Till Keller of the University Heart Center Hamburg in Germany, wrote in the study that quickly identifying patients at moderate to high risk of a heart attack is crucial because those individuals benefit the most from early and aggressive treatment.

A diagnosis of a heart attack from the biomarker test is based on elevated cardiac troponin levels that exceed the 99th percentile and demonstrate an increase or decrease over time. A test based on troponin was previously available, but the new finding is more sensitive and could identify heart attacks more quickly.

During the study, researchers enrolled 1,818 German patients with chest pain who were suspected of having acute coronary syndrome (such as a heart attack or angina) between 2007 and 2008.

Investigators measured 12 biomarkers, including highly sensitive troponin, upon hospital admission and again three hours later and six hours later. Of the patients, 413, or 23 percent, were discharged with a diagnosis of heart attack.

The highly sensitive troponin assay had a sensitivity of 82.3 percent on admission and a negative predictive value of 94.7 percent. After three hours the highly sensitive troponin assay had a sensitivity of 98.2 percent with a negative predictive value of 99.4 percent.

Researchers said the biomarker provides useful diagnostic information, and is accurate enough that they can safely rule out heart attack. It also can be valuable for ruling in the possibility of a heart attack.

“Use of hsTnI and cTnI assays in patients with suspected MI provides useful diagnostic information,” the researchers write. “Determination of hsTnI and cTnI values 3 hours after admission to the emergency department with use of the 99th percentile cutoff provides an NPV greater than 99 percent, potentially allowing a safe rule-out of MI. Application of the relative change in hsTnI or cTnI concentration within 3 hours after admission in combination with the 99th percentile diagnostic cutoff value on admission improves specificity and may facilitate an accurate early rule-in of MI.”

The study will be published in the Dec. 28 issue of the Journal of the American Medical Association.

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Review Date: 
December 22, 2011