Sensitive Blood Test Diagnoses Heart Attacks Faster

A high-sensitivity (hs) troponin T (cTnT) assay that has greater sensitivity and precision than the conventional fourth-generation cTnT assay currently in use in the USA has been recently approved.

The new high-sensitivity blood test for cardiac troponin, given in a hospital emergency room, was also found to be safe and effective. When patients present to emergency rooms with heart attack symptoms, doctors assess them in part by using a cardiac troponin test to measure a protein released into the blood when the heart is damaged.

Scientists at the University of Texas (UT) Southwestern Medical Center (Dallas, TX, USA) and their colleagues developed a procedure for assessing the results of the new test and compared it to existing practice using a conventional troponin test, which takes three hours to complete. Study participants were 536 patients admitted to an emergency room with heart attack symptoms, including chest pains and shortness of breath.

The team reported that in the cohort (mean age 55 years, 44% women), the final adjudicated diagnosis was myocardial infarction (MI) in 2.1%, unstable angina in 0.4%, and nonischemic myocardial injury in 17.0%. With the conventional assay, 80.4% of patients ruled out for MI at three hours. With the new hs-cTnT protocol, 83.8% ruled out by three hours, including 30.0% at baseline, 24.8% at one hour, and 28.9% at three hours. Compared with 19.6% of patients considered abnormal by the conventional assay, 16.2% of patients were abnormal under the new protocol.

Rebecca Vigen, MD, a cardiologist and lead author of the study, said, “We did not miss any heart attacks using this test in this population. The test also allowed us to determine faster that many patients who had symptoms of a heart attack were not having a heart attack than if we had relied on the traditional test. We anticipate that this procedure will allow many patients with chest pain to be given a 'yes' or 'no' diagnosis of whether they are having a heart attack faster.” The study was published on August 6, 2018, in the journal Circulation.

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University of Texas (UT) Southwestern Medical Center