title: Risk prediction with serial myeloperoxidase monitoring in patients with acute chest pain.
abstract: BACKGROUND
  Although myeloperoxidase (MPO) monitoring is predictive for cardiovascular outcomes in suspected acute coronary syndromes, the value of serial testing is unknown.
  
  
  METHODS
  We investigated the relationship between serial MPO concentrations in 490 individuals with acute chest pain and incident major adverse cardiac events (MACE) during 6 months of follow-up. We measured MPO with the CardioMPO assay, and cardiac troponin I (cTnI), with the Abbott Architect assay.
  
  
  RESULTS
  Plasma MPO concentrations during the first 16 h were higher in individuals who experienced MACE. Higher MPO quartiles predicted a greater likelihood of 6-month MACE at baseline [OR (95% CI), 2.4 (1.4-4.1), P = 0.001 for highest vs lowest quartile] and all subsequent time points, with strongest predictive ability found in 16-h postbaseline samples [9.9 (4.7-20.9), P < 0.001 for highest vs lowest quartile]. MPO was predictive for MACE among individuals whose cTnI remained within reference intervals (<0.028 μg/L). The lowest rate of missed cases was found when MPO was <640 pmol/L at baseline and all other time points. Serial MPO monitoring predicted MACE risk better than baseline MPO measurements alone (c statistic 0.813 vs 0.602; P = 0.002), including in individuals whose cTnI remained within reference intervals (c statistic 0.903; P = 0.009). Combined serial cTnI and MPO testing improved accuracy for predicting 6-month MACE, reduced the number of missed MACE events from cTnI testing alone, and improved risk classification in 26.1% of patients.
  
  
  CONCLUSIONS
  MPO concentrations are predictive of outcome up to 16 h after presentation with chest pain and predict events missed by cTnI testing, supporting a potential role in rapid patient triage.
authors.affiliation: Department of Cardiovascular Medicine, Cleveland Clinic, Cleveland, OH, USA. nichols1@ccf.org
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Nicholls
authors.forename: W H Wilson
authors.initials: WH
authors.lastname: Tang
authors.forename: Danielle
authors.initials: D
authors.lastname: Brennan
authors.forename: Marie-Luise
authors.initials: ML
authors.lastname: Brennan
authors.forename: Shirley
authors.initials: S
authors.lastname: Mann
authors.forename: Steven E
authors.initials: SE
authors.lastname: Nissen
authors.forename: Stanley L
authors.initials: SL
authors.lastname: Hazen
mesh_terms: D054058:Acute Coronary Syndrome / Q000175:diagnosis*; D000368:Aged; D000789:Angina, Unstable / Q000175:diagnosis; D015415:Biomarkers / Q000097:blood; D002637:Chest Pain / Q000175:diagnosis*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis; D009195:Peroxidase / Q000097:blood*; D012372:ROC Curve; D012016:Reference Values; D018570:Risk Assessment; D019210:Troponin I / Q000097:blood
chemical_list: D015415:Biomarkers; D019210:Troponin I; D009195:Peroxidase