title: What is the 30-day rate of adverse cardiac events in chest pain patients with ED troponin I assays≤99th centile using a contemporary sensitive assay? An exploratory analysis.
abstract: OBJECTIVE
  For nonhigh-risk patients who 'rule out' for acute coronary syndrome, Australasian guidelines recommend further testing to identify coronary artery disease. Testing is usually performed as an outpatient procedure. This recommendation has not changed with the advent of sensitive biomarker assays. We aimed to determine the 30-day rate of adverse cardiac events in emergency department (ED) chest pain patients without known coronary artery disease who had ED troponin I (TnI) assays≤99th centile using a contemporary troponin assay, stratified by the Heart Foundation (HF; Australia) risk group.
  
  
  METHODS
  This study is a substudy of a prospective observational study. Clinical and investigational data were collected. The primary outcome of interest was the proportion of patients with ED TnI assays≤99th centile who suffered a major adverse cardiac event (MACE; myocardial infarction, death, major arrhythmia) within 30 days, stratified by HF risk group. The secondary outcome was the rate of MACE or revascularization in non-HF high-risk patients.
  
  
  RESULTS
  A total of 460 patients were studied. Among them, 388 had no TnI assay>99th centile. There was one MACE in this group [0.26%, 95% confidence interval (CI) 0.05-1.5%]: a non-ST segment elevation myocardial infarction in an HF high-risk patient. There were no MACEs among nonhigh-risk patients (0%, 95% CI 0-1.5%), and one patient had revascularization (0.4%; 95% CI 0.7-2.2%).
  
  
  CONCLUSIONS
  Among ED patients presenting with suspected acute coronary syndrome, adverse cardiac events at 30 days are rare in nonhigh-risk patients with contemporary TnI assays<99th centile.
authors.affiliation: aJoseph Epstein Centre for Emergency Medicine at Western Health bThe University of Melbourne, St Albans, Victoria, Australia.
authors.forename: Anne-Maree
authors.initials: AM
authors.lastname: Kelly
authors.forename: Sharon
authors.initials: S
authors.lastname: Klim
mesh_terms: D054058:Acute Coronary Syndrome / Q000097:blood / Q000175:diagnosis / Q000401:mortality; D000328:Adult; D000368:Aged; D001145:Arrhythmias, Cardiac / Q000097:blood / Q000453:epidemiology / Q000401:mortality; D015415:Biomarkers / Q000097:blood; D002637:Chest Pain / Q000097:blood* / Q000209:etiology / Q000401:mortality; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood* / Q000453:epidemiology / Q000401:mortality; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012307:Risk Factors; D019210:Troponin I / Q000097:blood*
chemical_list: D015415:Biomarkers; D019210:Troponin I