Prevalence, Determinants, and Clinical Associations of High-Sensitivity Cardiac Troponin in Patients Attending Emergency Departments

Kuan Ken Lee,Matthew Gibbins,Nicholas L. Mills,Atul Anand,David A. McAllister,Megan Griffiths,David E. Newby,Anoop S.V. Shah,Alasdair J. Gray,Fiona Strachan,Andrew R. Chapman,Amar Vaswani,Ala Noaman

doi:10.1016/j.amjmed.2018.10.002

Abstract

BackgroundHigh-sensitivity cardiac troponin assays may improve the diagnosis of myocardial infarction but increase the detection of elevated cardiac troponin in patients without acute coronary syndrome. MethodsIn a prospective cohort study, we evaluated the prevalence, determinants, and outcome of patients with elevated cardiac troponin attending the emergency department without suspected acute coronary syndrome. We measured high-sensitivity cardiac troponin in 918 consecutive patients attending the emergency department without suspected acute coronary syndrome who had blood sampling performed by the attending clinician. Elevated high-sensitivity cardiac troponin I was defined as concentrations above the sex-specific 99th percentile threshold. Clinical demographics, physiological measures, and all-cause mortality at 1 year associated with elevated high-sensitivity cardiac troponin concentrations were recorded. ResultsElevated cardiac troponin concentration occurred in 114 (12.4%) patients, of whom 2 (0.2%), 3 (0.3%), and 109 (11.9%) were adjudicated as type 1 myocardial infarction, type 2 myocardial infarction, and myocardial injury, respectively. Elevated troponin concentrations were associated with increasing age, worsening renal function, multimorbidity, and adverse physiology. Across a total of 912 patient-years follow-up, cardiac troponin concentration was a strong predictor of death (hazard ratio [HR] 1.26 per 2-fold increase, 95% confidence interval [CI] 1.06 to 1.49) independent of age, sex, multimorbidity, and adverse physiology. ConclusionsHigh-sensitivity cardiac troponin concentrations were elevated in 1 in 8 consecutive patients without suspected acute coronary syndrome attending the emergency department and were associated with increasing age, multimorbidity, adverse physiology, and death. Elevated cardiac troponin in unselected patients predominantly reflects myocardial injury rather than myocardial infarction.

Highlights

High-sensitivity cardiac troponin assays may improve the diagnosis of myocardial infarction but increase the detection of elevated cardiac troponin in patients without acute coronary syndrome
Given the increasing use of high-sensitivity cardiac troponin assays in clinical practice and the potential diagnostic challenges that elevated troponin concentrations may pose, we evaluated the prevalence and factors associated with an elevated cardiac troponin concentration in consecutive patients to the Emergency Department who did not have suspected acute coronary syndrome in whom the attending clinician performed blood sampling
This might have introduced some confounding by indication, we believe this ensured that our study is representative of the broad population of patients presenting to the Emergency Department who were sufficiently unwell to require blood testing. It is in this group of patients in which diagnostic uncertainty may arise should troponin testing is requested indiscriminately. This is the first study that has evaluated high-sensitivity cardiac troponin concentrations in consecutive patients attending an Emergency Department without suspected acute coronary syndrome, in whom blood sampling was undertaken by the attending physician

Summary

Introduction

High-sensitivity cardiac troponin assays may improve the diagnosis of myocardial infarction but increase the detection of elevated cardiac troponin in patients without acute coronary syndrome. METHODS: In a prospective cohort study, we evaluated the prevalence, determinants, and outcome of patients with elevated cardiac troponin attending the emergency department without suspected acute coronary syndrome. We measured high-sensitivity cardiac troponin in 918 consecutive patients attending the emergency department without suspected acute coronary syndrome who had blood sampling performed by the attending clinician. Across a total of 912 patient-years follow-up, cardiac troponin concentration was a strong predictor of death (hazard ratio [HR] 1.26 per 2-fold increase, 95% confidence interval [CI] 1.06 to 1.49) independent of age, sex, multimorbidity, and adverse physiology. CONCLUSIONS: High-sensitivity cardiac troponin concentrations were elevated in 1 in 8 consecutive patients without suspected acute coronary syndrome attending the emergency department and were associated with increasing age, multimorbidity, adverse physiology, and death.

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