title: Serial multiple biomarkers in the assessment of suspected acute coronary syndrome: multiple infarct markers in chest pain (MIMIC) study.
abstract: OBJECTIVE
  To evaluate the accuracy of a 2-h serial multiple biomarker (SMB) protocol for exclusion of myocardial infarction (MI) in the Emergency Department.
  
  
  METHODS
  A prospective, multicentre, observational study enrolled patients undergoing evaluation for possible MI. Blood samples at presentation and 2 h later were analysed for myoglobin, creatinine kinase-MB, troponin-I and B-natriuretic peptide. Thrombolysis in Myocardial Infarction (TIMI) score and National Heart Foundation of Australia/Cardiac Society of Australia and New Zealand (NHF/CSANZ) guideline for acute coronary syndrome were used to determine clinical risk. Primary outcome was MI diagnosed at index presentation. Secondary outcome was composite of all-cause mortality, MI and previously unplanned coronary revascularisation within 30 days.
  
  
  RESULTS
  1758 patients were recruited. 168 (11%) of 1501 with data sufficient for analysis had MI, and 223 (14%) of 1620 had a secondary outcome. SMB sensitivity and specificity were 0.90 (95% CI 0.84 to 0.94) and 0.41 (95% CI 0.39 to 0.44) for MI. For 30-day outcome, SMB sensitivity and specificity were 0.84 (95% CI 0.78 to 0.88) and 0.41 (95% CI 0.39 to 0.44), compared with standard 8-12 h troponin sensitivity and specificity of 0.79 (95% CI 0.73 to 0.84) and 0.96 (95% CI 0.95 to 0.97). Combined with risk scores, SMB had sensitivity and specificity for MI of 0.99 (0.96 to 1.00) and 0.11 (95% CI 0.09 to 0.12) for TIMI score 0, compared with 0.98 (95% CI 0.94 to 0.99) and 0.31 (95% CI 0.29 to 0.34) for NHF/CSANZ low/intermediate risk groups.
  
  
  CONCLUSIONS
  SMB alone is not sufficiently sensitive to exclude MI. Combined with risk scoring, SMB appears to identify patients at lower risk. This requires prospective validation.
authors.affiliation: Centre for Clinical Research in Emergency Medicine, Royal Perth Hospital, Perth, Australia. stephen.macdonald@health.wa.gov.au
authors.forename: Stephen P J
authors.initials: SP
authors.lastname: Macdonald
authors.forename: Yusuf
authors.initials: Y
authors.lastname: Nagree
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Fatovich
authors.forename: Michael
authors.initials: M
authors.lastname: Phillips
authors.forename: Simon G A
authors.initials: SG
authors.lastname: Brown
mesh_terms: D054058:Acute Coronary Syndrome / Q000175:diagnosis*; D000368:Aged; D015415:Biomarkers / Q000097:blood*; D002637:Chest Pain / Q000175:diagnosis*; D003404:Creatinine / Q000097:blood; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis*; D009211:Myoglobin / Q000097:blood; D045265:Natriuretic Peptides / Q000097:blood; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D019210:Troponin I / Q000097:blood
chemical_list: D015415:Biomarkers; D009211:Myoglobin; D045265:Natriuretic Peptides; D019210:Troponin I; D003404:Creatinine