Single-dose high-sensitivity cardiac troponin for prognostic evaluation in syncope

Background Measurement of cardiac troponin has been used in patients presenting to the emergency department with syncope. However, the specific interpretation of results and the necessity for serial troponin measurements in this context have not yet been established. Purpose The aim of this study was to evaluate the prognostic value of a single high-sensitivity troponin measurement in patients presenting to the emergency department with syncope, and to determine whether additional measurements improve prognostic accuracy in this setting. Methods A historical cohort study was conducted using medical records from 220 patients aged 18 years or older who presented to an emergency department with syncope between 2021 and 2023. Four strategies were assessed and compared for their prognostic value: (1) a single troponin measurement, (2) the ESC 0/1-Hour Algorithm (as applied in chest pain assessment), (3) a ‘classical’ syncope risk score (Osservatorio Epidemiologico della Sincope nel Lazio – OESIL), and (4) a ‘modern’ risk score (Canadian Syncope Risk Score – CSRS). Telephone contact was made to obtain consent for medical record review and to evaluate out-of-hospital outcomes. The primary outcome was a composite event of all-cause mortality and/or major cardiovascular events (stroke, life-threatening arrhythmia, pacemaker or cardioverter-defibrillator implantation, acute myocardial infarction, pulmonary embolism, intracranial haemorrhage, or percutaneous/surgical valve intervention) within 30 days. The secondary outcome was all-cause mortality within 30 days. Results Optimal troponin cut-off points determined by ROC curve analysis for the composite outcome and 30-day mortality were 12 ng/L and 41 ng/L, respectively. The numerically highest AUC for the composite endpoint was observed for CSRS (0.85), and for mortality, for troponin (0.94). Multivariate analysis showed that high-sensitivity troponin levels above 12 ng/L were independently associated with the composite outcome (relative risk [RR] 2.63; 95% CI: 1.11–6.26). The ESC 0/1-Hour Algorithm was associated with an RR of 3.45 (95% CI: 1.09–11.0), and CSRS with an RR of 6.18 (95% CI: 2.58–14.8), whereas OESIL was not an independent predictor. Troponin levels above 41 ng/L were independently associated with death (RR 38.7; 95% CI: 6.85–218), CSRS with RR 4.48 (95% CI: 1.45–13.8), and OESIL with RR 11.3 (95% CI: 2.87–44.1). The ESC 0/1-Hour Algorithm classified as very low or low demonstrated a negative predictive value of 100%. Conclusion A single high-sensitivity troponin measurement demonstrated satisfactory accuracy as a prognostic tool for evaluating syncope in the emergency department.