Cardiac Troponin Cut-Offs ID Low-Risk Patients With Suspected Acute Coronary Syndrome
By Frances Morin
PARIS -- September 2, 2019 -- Use of a high-sensitivity cardiac troponin I assay and key risk stratification thresholds in patients suspected of having acute coronary syndrome is highly effective in identifying low-risk patients, allowing for the avoidance of unnecessary and costly interventions, researchers reported here at the 2019 European Society of Cardiology (ESC) Congress.
“The HISTORIC trial is the first trial to evaluate the effectiveness and safety of implementing an early rule-out pathway in consecutive patients with suspected acute coronary syndrome,” said Nicholas Mills, MD, University of Edinburgh, Edinburgh, Scotland. “Our early rule-out pathway, incorporating a single high-sensitivity cardiac troponin test at presentation with separate risk stratification and diagnostic thresholds, was more effective than the 99th percentile and serial testing 6 to 12 hours from symptom onset.”
He said that implementation of the assay and risk stratification reduced hospital length of stay by 3.3 hours and increased the proportion of patients discharged from the emergency department by 57%.
The researchers previously determined that cardiac troponin I concentrations of
To prospectively validate the risk stratification thresholds in real-world practice, the researchers evaluated data on 48,282 patients with suspected acute coronary syndrome at 10 hospitals in Scotland. Using the Abbott high-sensitive troponin I assay, the authors compared the performance of the limit of detection (
Patients with myocardial injury at presentation and
Among the 32,837 patients who were included in the analysis, 23,260 (71%) had cardiac troponin I concentrations
For the primary outcome of MI or cardiac death within 30 days, the negative predictive value (NPV) was 99.8% in those with cardiac troponin I concentrations
The NPV was consistent in men and women and across all age groups at each of the concentrations, although the proportion of patients identified as low-risk decreased with older age.
The risk of MI or cardiac death at 12 months was 77% lower in those with cardiac troponin I concentrations of
While the study was unable to conclude non-inferiority at 30 days, there was no increase in the primary safety outcome or any secondary safety outcome measure at 1 year.
“Most guidelines recommend ruling in and ruling out myocardial infarction using a single threshold [99th percentile],” said Dr. Mills. “Our trial demonstrates that using separate risk stratification and diagnostic thresholds allows myocardial infarction to be ruled out at presentation in more patients without additional risk.”
[Presentation title: HISTORIC - High-Sensitivity Cardiac Troponin on Presentation to Rule Out Myocardial Infarction: A Stepped-Wedge Cluster Randomised Controlled Trial. Abstract 2309]