Researchers determine whether a new, rapid blood test for heart attack diagnosis could rule out heart attacks faster than current methods, to improve decision making and treatment.
Millions of people report to hospital emergency departments every year with chest pain. Not all of these people have suffered a heart attack or myocardial infarction. In fact, up to two-thirds of those reporting to emergency departments with chest pains are not experiencing a heart attack. A heart attack is diagnosed by recording an electrocardiogram (ECG) and checking for heart muscle proteins such as troponin I and troponin T that are released into the blood upon heart muscle injury. While cardiac troponin I and cardiac troponin-T-based tests are very reliable, in many patients, the levels of these proteins fall in a grey area, making heart attack diagnosis difficult. Such patients are generally placed under observation and require repeat testing before a decision is made.
A new test developed by a group of researchers working across various hospitals in Europe shows improved diagnostic accuracy compared to the troponin tests, especially in patients with chest pain of fewer than three hours in duration. The results of the study were published recently in the British Medical Journal.1,2
The test analyses the concentrations of a protein called cardiac myosin binding protein C (cMyC). The study involved 1,954 patients who reported to the emergency departments of various hospitals with acute chest pain. The study participants had a median age of 62 years, and 36 had a previous history of coronary artery disease. Blood samples were collected from these patients at various time points after admission and used for the new cardiac myosin-binding protein test, as well as for the high-sensitivity cardiac troponin I, high-sensitivity troponin T, and the standard troponin I test.
Analysis of the test results showed that the diagnostic accuracy of the new test for acute myocardial infarction was comparable to that of the high-sensitivity cardiac troponin I and troponin T tests and superior to that of the standard troponin I test. In patients within three hours of chest pain onset, the new test was superior to both the high sensitivity cardiac troponin tests.
This study shows that cardiac myosin-binding protein C represents a very specific biomarker for myocardial infarction and cardiac injury. Testing for serum levels for this protein in patients who report acute chest patient may help in early heart attack diagnosis, improve treatment outcomes, and reduce hospital burden. The researchers involved are hoping to introduce the test in hospitals over the next five years.
Written by Usha B. Nair, Ph.D.
1) Kaier TE, Twerenbold R, Puelacher C, Marjot J, Imambaccus N, and Boeddinghaus J et al. Direct Comparison of Cardiac Myosin-Binding Protein C with Cardiac Troponins for the Early Diagnosis of Acute Myocardial Infarction. Circulation. 2017 Sep 26. pii: CIRCULATIONAHA.117.028084. doi: 10.1161/CIRCULATIONAHA.117.028084. [Epub ahead of print] PubMed PMID: 28972002.
2) Wise J. Rapid blood test could speed up myocardial infarction diagnosis. BMJ. 2017 Sep 27;358:j4502. doi: 10.1136/bmj.j4502. PubMed PMID: 28954719.