Research presented at the European Society of Cardiology Congress suggests that a new, highly sensitive, 1-hour troponin I assay may be used to assess patients for acute myocardial infarction (AMI), as examined in the Biomarkers in Acute Cardiovascular Care (BACC) study.
Researchers at the University Heart Centre Hamburg and the German Centre for Cardiovascular Research have developed an algorithm intended to reduce mortality and cut triage times to 1 hour in patients presenting to emergency departments with chest pain suggestive of AMI.
The BACC study included 1045 patients with acute chest pain suggestive of AMI. Current AMI triage guidelines require analysis of cardiac troponin I levels—a marker of myocyte necrosis—at admission and again 3 hours later. The BACC study assessed patients using both the standard 3-hour assay and the highly sensitive 1-hour assay developed by Dirk Westermann, MD, PhD, and colleagues. One hundred eighty-four patients were diagnosed with AMI based on the standard approach and were kept in the hospital, while the remaining patients were sent home. Researchers followed all patients for 6 months.
“There is clinical need to rapidly and safely rule in or rule out AMI in patients with acute chest pain in order to initiate fast evidence-based treatment for patients with AMI and limit overuse of scarce medical resources in the emergency room discharging patients without acute cardiac conditions,” Dr. Westermann said.
Currently, troponin levels are considered abnormal at 27 ng/L. After comparing the results of both assays, researchers determined the best troponin I cutoff value to rule out AMI is actually much lower at 6 ng/L. The algorithm had negative predictive values of 99.7% after 1 hour and 100% after 3 hours. After applying the new cutoffs to the BACC cohort, researchers found mortality would have been much lower if patients had been triaged with the new algorithm rather than the routine 3-hour approach.
After testing the clinical relevance of the new cutoff using data from the BiomarCaRE study—including 75 000 individuals from the general population—researchers confirmed that individuals with a troponin I level higher than 6 ng/L were ultimately at increased risk for death or cardiovascular disease, while patients with levels below this cutoff could be safely discharged home.
“Use of this algorithm in patients with suspected AMI allows for highly accurate and rapid rule-out as well as rule-in, enabling safe discharge or rapid treatment initiation,” Dr. Westermann said. “This rapid algorithm might be applicable to clinical practice without a loss of diagnostic safety.”
- Neumann JT, Sörensen NA, Schwemer T, et al. FP Number 1161: Accurate and Rapid Diagnosis of Myocardial Infarction Using a High-Sensitivity Troponin I 1-Hour Algorithm. Presented at: European Society of Cardiology Congress 2015; August 29–September 2, 2015; London, UK.