Sensitive troponin assay predicts outcome in syncope
- 1Emergency Medicine Research Group Edinburgh, Royal Infirmary of Edinburgh, Edinburgh, UK
- 2BHF/University Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
- 3MRC Hub for Trials Methodology Research, Centre for Population Health Sciences, University of Edinburgh Medical School, Edinburgh, UK
- Correspondence to Dr Matthew J Reed, Emergency Medicine Research Group Edinburgh, Royal Infirmary of Edinburgh, 51 Little France Crescent, Edinburgh, EH16 4SA, UK;
- Accepted 3 August 2012
- Published Online First 8 September 2012
Aims To assess whether plasma troponin concentration measured by a sensitive assay can predict 1-month and 1-year serious outcome, or all-cause death in patients presenting with syncope to the emergency department (ED).
Methods Prospective cohort study of admitted adult patients presenting to the ED after an episode of syncope who had plasma troponin measured 12 h after syncope using the ARCHITECT STAT sensitive troponin I assay (Abbott Diagnostics). Primary endpoints were the composite endpoint of serious outcome or all-cause death at 1 month and 1 year.
Results Between 1 March 2007 and 22 July 2008, 338 of 528 patients admitted from the ED with syncope had plasma troponin concentrations determined. Troponin concentrations were above the limit of detection in 261 (77%) patients. Patients numbering 120 (36%) had a troponin concentration ≥0.03 ng/ml (99th percentile of normal reference population), and 66 (20%) had concentrations ≥0.05 ng/ml (local diagnostic threshold for myocardial infarction). The proportion of patients with a composite serious outcome increased across patients stratified into quintiles based on peak troponin concentration at 1 month (0%, 9%, 13%, 26%, 70%) and at 1 year (10%, 22%, 26%, 52%, 85%).
Conclusions The majority of patients admitted from the ED with syncope have detectable plasma troponin concentrations. Peak troponin concentration was associated with increasing risk of serious outcome and death, and this risk increases with higher troponin concentrations. Troponin may have a future role in the risk stratification of patients with syncope.