A single high-sensitivity cardiac troponin T compared to the HEART score for a rapid rule-out of acute myocardial infarction at a prehospital emergency clinic

Abstract

Abstract Background Patients presenting with acute chest pain outside of hospitals represent a diagnostic challenge. Purpose We aimed to validate whether a single high-sensitivity cardiac troponin T (hs-cTnT) safely can rule out acute myocardial infarction (AMI) in a primary care emergency setting. In addition, we aimed to investigate if the hs-HEART (History, Electrocardiogram (ECG), Age, Risk factors, and hs-Troponin) score would add valuable diagnostic information. Methods This is a secondary analysis from a prospective diagnostic study, including 1711 patients with acute non-specific chest pain presenting to a primary care emergency clinic from November 2016 to October 2018. The European Society of Cardiology (ESC) 0/1-hour algorithm triages patients towards direct rule-out if the 0-hour hs-cTnT is below 5 ng/L, combined with a normal ECG and a 3-hour symptom duration. The hs-HEART score (0–10 points) was calculated retrospectively, and a score ≤3 points was considered low-risk. In addition, a modified hs-HEART score, with more comparable hs-cTnT cut-off values, was applied. The primary endpoint was AMI during the index episode; the secondary the 90-day incidence of AMI (including index) and all-cause death. Results Among 1711 patients, 61 (3.6%) had an AMI, and 525 (30.7%) were assigned towards direct rule-out. With no AMIs in this group, the rule-out safety was high (negative predictive value (NPV) and sensitivity 100%). The hs-HEART score triaged more patients (n=966) as low-risk, but missed six AMIs (NPV 99.4% and sensitivity 90.2%). The modified hs-HEART score (n=707, AMI=3) increased the low-risk sensitivity to 95.1%. The 90-day incidence of AMI and all-cause death in the direct rule-out, low-risk hs-HEART, and modified hs-HEART group, were 0.0%, 0.7%, and 0.4%, respectively. Conclusions The ESC direct rule-out approach, with a single hs-cTnT below 5 ng/L, combined with a normal ECG, and a 3-hour symptom duration, is superior to the two hs-HEART scores in ruling out AMI in a primary care emergency setting. Funding Acknowledgement Type of funding source: Public Institution(s). Main funding source(s): The Norwegian Research Fund for General Practice