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BASEL, SWITZERLAND – Can a new algorithm speed the process by which emergency physicians rule-out or rule-in myocardial infarction (MI)?
A recently published study by Swiss and Spanish researchers suggests it can. Led by investigators from the Universitätsspital Basel in Switzerland, the trial’s results appeared online recently in CMAJ, the Canadian Medical Association Journal.
"Introducing the high-sensitivity cardiac troponin T 1-hour algorithm into clinical practice would represent a profound change and it is therefore important to determine if it works in a large patient group," noted lead author Tobias Reichlin, MD, of the Division of Cardiology at University Hospital Basel.
The algorithm previously was tested in a small pilot study, also led by Reichlin, which was published in JAMA Internal Medicine in 2012. Noting that MIs account for about 10% of all ED consultations, the authors suggested that the newly developed sensitive and high-sensitivity cardiac troponin (hs-cTn) assays enabled measurement of cTn concentrations not reliably detected with prior generations of tests. They also raised the possibility that the new tests, which have been shown to improve the diagnostic accuracy in the early diagnosis of MI, would make it possible to rule-in or rule-out heart attacks more rapidly.
For the more recent clinical trial of the algorithm, the researchers enrolled 1,320 patients who visited EDs with suspected acute MI and applied the algorithm to blood samples.
As a result, the authors report, they were able to determine that 786 (60%) of patients did not have an acute MI, 216 (16%) were "rule-in" and 318 (24%) were to be observed because of inconclusive results.
The final diagnoses were then reviewed by two independent cardiologists using all available information, including coronary angiography, echocardiography, follow-up data and serial measurements of high-sensitivity cardiac troponin T levels. After that process, acute MI was the final diagnosis in 17.3% of patients.
Cumulative 30-day mortality was 0.0%, 1.6% and 1.9% in patients classified in the rule-out, observational and rule-in groups, respectively.
“This rapid strategy incorporating high-sensitivity cardiac troponin T baseline values and absolute changes within the first hour substantially accelerated the management of suspected acute MI by allowing safe rule-out as well as accurate rule-in of acute MI in 3 out of 4 patients,” the study concludes.