Heart attack marker troponin may help with diagnosis

Heart attacks can be difficult to diagnose. Moreover, doctors often can’t tell a cardiac patient whether he or she is likely to suffer another heart attack. A new test to detect a particular substance in the blood may help with that problem but, if adopted for widespread use, it could also dramatically raise the number of heart attack diagnoses.

In the study, published Tuesday in the Journal of the American Medical Assn., researchers reported success using a more sensitive test to identify troponin, a cardiac muscle protein. The protein is normally found in low amounts in the blood stream. But during or after a heart attack, when the heart muscle has been damaged, the levels increase. Doctors have been looking for a marker to help them better identify someone who may be having a heart attack but who only has vague symptoms, such as shortness of breath. But there has been debate about whether troponin tests are accurate enough.

The new test was performed on 2,092 patients admitted to a hospital with a suspected heart attack or unstable angina. Adopting a troponin score that is lower than what has traditionally been used resulted in more accurate diagnoses of actual heart attacks, said the authors of the study, from Scotland, and resulted in better care, fewer deaths and fewer recurrent heart attacks.

Lowering the threshold for detecting a heart attack to a score of 0.05 nanograms per milliliter for troponin, the score used in the study, will increase the number of people diagnosed with a heart attack -- perhaps substantially, the authors said.

“This greater diagnostic performance will have implications for public health targets, government statistics, health care resources, and on the employment prospects and insurance policies of our patients,” the wrote.

Related: Heart attacks, if survived, bring drastic change

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