Heart attacks, also known as acute myocardial infarctions (AMI), occur when blood flow is cut off to the heart muscle, causing cells to die. As these heart cells die, they release proteins known as troponin T, which serve as cardiac biomarkers to alert doctors of AMI events.
Both the new diagnostic method and the earlier generation methods rely on detection of troponin T. However, the new test is significantly more sensitive at detecting troponin release within a short amount of time.
The test, known formally as high-sensitivity cardiac troponin T (hs-cTnT), was developed by Roche to be effective at diagnosing heart attacks as well as ruling it out.
Researchers formed an international collaboration to test the specificity and sensitivity of the new diagnostic method. Known as TRAPID-AMI, the prospective observational clinical trial was conducted in over 12,000 patients at 12 institutions from 9 countries and 3 continents. Patients who presented with suspected heart attacks with early onset of chest pains had blood tests drawn at pre-defined hourly intervals.
Based on Troponin T levels, the algorithm classified patients into 3 groups: the rule-out zone (negative AMI diagnosis), the rule-in zone (positive AMI diagnosis), and the observational zone.
Overall, the new hs-cTnT test showed high accuracy and improved detection time significantly. For rule-in zone, the test had a respectable positive predictive value of 77.2% and a high specificity of 96.1%. What’s more, the test accurately predicted those who weren’t having heart attacks: in the rule-out zone, the test performed at 99.1% negative predictive value and 96.7% sensitivity.
These results show that the new Troponin T diagnostic test can predict heart attacks with high accuracy. Even more impressive, the new test dramatically shortens diagnosis time to just one hour as opposed to three hours or more.
The improvement in diagnosis time is a huge achievement that’s especially appreciated in heart attack events where time is of the utmost essence. It’s estimated that every 30 minutes of delay of prompt treatment increases the mortality risk by 7.5% in patients with AMIs. In contrast, patients who have delayed “rule out” diagnoses suffer longer ER times at higher costs and anxiety. Unsurprisingly, both doctors and patients are hopeful for the prospects of the new one-hour test.
Additional source: MNT