A high-sensitivity troponin I assay promises quicker turnaround times for triaging patients suspected of heart attack in the emergency department. Research presented at the European Society of Cardiology (ESC) Congress 2015 found that using a much lower than normal cut-off with the high-sensitivity cardiac troponin I test along with a treatment algorithm enabled clinicians to safely rule out heart attack patients within 1 hour.
This compares with the standard 3-hour rule used with current generation troponin assays. Under this protocol recommended by various professional guidelines, analysis of cardiac troponin I takes place upon the patient’s admission to the hospital, and once again 3 hours later. This requires that patients wait a long time in the hospital to see if they should be admitted or discharged.
“There is an urgent need for fast decision-making for this growing patient population,” principal investigator Dirk Westermann, MD, PhD, from the University Heart Centre Hamburg, and the German Centre for Cardiovascular Research, said in a statement issued by the ESC.
For the Biomarkers in Acute Cardiovascular Care, or BACC, study, researchers assessed both the 3-hour protocol and contemporary assay and a 1-hour protocol and high-sensitivity assay in more than 1,000 patients who presented at a university hospital in Germany with severe chest pain indicative of heart attack.
While most of the patients were discharged home, 184 under the standard approach stayed in the hospital with a diagnosis of acute myocardial infarction.
Currently, a reading of 27 ng/L troponin I levels—above the 99th percentile of a healthy reference population—is viewed as abnormal. After tracking all of the patients for 6 months, researchers determined that a much lower reading of 6 ng/L was the optimal troponin I cut-off value to rule out heart attack.
Data from the BiomarCaRE study, which has measured troponin I in more than 75,000 people in the general population, was then used to test this lower cut-off value. Researchers found it was safe to discharge patients with levels below 6 ng/L, whereas those with values higher than this were at high risk for heart disease or death from cardiovascular events.
In applying the lower cut-off value to the study’s cohort, they also determined that compared with the standard 3-hour approach, triage protocols with the new 1-hour method would have resulted in lower death rates.
“The standard approach underestimated risk for many patients and resulted in high mortality. In addition, using the rapid, sensitive assay would have reduced usage of the emergency room and scarce medical resources, enabling a faster diagnosis and better treatment,” Westermann said.