title: Two-Hour Algorithm for Triage toward Rule-Out and Rule-In of Acute Myocardial Infarction by Use of High-Sensitivity Cardiac Troponin I.
abstract: BACKGROUND
  The early triage of patients toward rule-out and rule-in of acute myocardial infarction (AMI) is challenging. Therefore, we aimed to develop a 2-h algorithm that uses high-sensitivity cardiac troponin I (hs-cTnI).
  
  
  METHODS
  We prospectively enrolled 1435 (derivation cohort) and 1194 (external validation cohort) patients presenting with suspected AMI to the emergency department. The final diagnosis was adjudicated by 2 independent cardiologists. hs-cTnI was measured at presentation and after 2 h in a blinded fashion. We derived and validated a diagnostic algorithm incorporating hs-cTnI values at presentation and absolute changes within the first 2 h.
  
  
  RESULTS
  AMI was the final diagnosis in 17% of patients in the derivation and 13% in the validation cohort. The 2-h algorithm developed in the derivation cohort classified 56% of patients as rule-out, 17% as rule-in, and 27% as observation. Resulting diagnostic sensitivity and negative predictive value (NPV) were 99.2% and 99.8% for rule-out; specificity and positive predictive value (PPV) were 95.2% and 75.8% for rule-in. Applying the 2-h algorithm in the external validation cohort, 60% of patients were classified as rule-out, 13% as rule-in, and 27% as observation. Diagnostic sensitivity and NPV were 98.7% and 99.7% for rule-out; specificity and PPV were 97.4% and 82.2% for rule-in. Thirty-day survival was 100% for rule-out patients in both cohorts.
  
  
  CONCLUSIONS
  A simple algorithm incorporating hs-cTnI baseline values and absolute 2-h changes allowed a triage toward safe rule-out or accurate rule-in of AMI in the majority of patients.
authors.affiliation: Cardiovascular Research Institute Basel (CRIB), Department of Cardiology, and Department of Internal Medicine, University Hospital Basel, Basel, Switzerland;
authors.forename: Jasper
authors.initials: J
authors.lastname: Boeddinghaus
authors.affiliation: Cardiovascular Research Institute Basel (CRIB), Department of Cardiology, and.
authors.forename: Tobias
authors.initials: T
authors.lastname: Reichlin
authors.affiliation: Department of Emergency Medicine, Royal Brisbane and Women's Hospital, Brisbane, Australia; School of Public Health, The Queensland University of Technology, Brisbane, Australia;
authors.forename: Louise
authors.initials: L
authors.lastname: Cullen
authors.affiliation: Department of Emergency Medicine, Royal Brisbane and Women's Hospital, Brisbane, Australia; School of Public Health, The Queensland University of Technology, Brisbane, Australia;
authors.forename: Jaimi H
authors.initials: JH
authors.lastname: Greenslade
authors.affiliation: School of Public Health, The Queensland University of Technology, Brisbane, Australia; School of Medicine, The University of Queensland, Brisbane, Australia;
authors.forename: William A
authors.initials: WA
authors.lastname: Parsonage
authors.affiliation: School of Medicine, The University of Queensland, Brisbane, Australia;
authors.forename: Christopher
authors.initials: C
authors.lastname: Hammett
authors.affiliation: Department of Medicine, University of Otago, Christchurch, New Zealand; Emergency Department, Christchurch Hospital, Christchurch, New Zealand;
authors.forename: John W
authors.initials: JW
authors.lastname: Pickering
authors.affiliation: Department of Emergency Medicine, Royal Brisbane and Women's Hospital, Brisbane, Australia; School of Public Health, The Queensland University of Technology, Brisbane, Australia;
authors.forename: Tracey
authors.initials: T
authors.lastname: Hawkins
authors.affiliation: Emergency Department, Christchurch Hospital, Christchurch, New Zealand;
authors.forename: Sally
authors.initials: S
authors.lastname: Aldous
authors.affiliation: Cardiovascular Research Institute Basel (CRIB), Department of Cardiology, and.
authors.forename: Raphael
authors.initials: R
authors.lastname: Twerenbold
authors.affiliation: Cardiovascular Research Institute Basel (CRIB).
authors.forename: Karin
authors.initials: K
authors.lastname: Wildi
authors.affiliation: Cardiovascular Research Institute Basel (CRIB), Department of Cardiology, and Department of Internal Medicine, University Hospital Basel, Basel, Switzerland;
authors.forename: Thomas
authors.initials: T
authors.lastname: Nestelberger
authors.affiliation: Cardiovascular Research Institute Basel (CRIB), Department of Cardiology, and Department of Internal Medicine, University Hospital Basel, Basel, Switzerland;
authors.forename: Karin
authors.initials: K
authors.lastname: Grimm
authors.affiliation: Cardiovascular Research Institute Basel (CRIB), Department of Cardiology, and.
authors.forename: Maria
authors.initials: M
authors.lastname: Rubini-Gimenez
authors.affiliation: Cardiovascular Research Institute Basel (CRIB).
authors.forename: Christian
authors.initials: C
authors.lastname: Puelacher
authors.affiliation: Cardiovascular Research Institute Basel (CRIB).
authors.forename: Vera
authors.initials: V
authors.lastname: Kern
authors.affiliation: Laboratory Medicine, University Hospital Basel, Basel, Switzerland.
authors.forename: Katharina
authors.initials: K
authors.lastname: Rentsch
authors.affiliation: Emergency Department, Christchurch Hospital, Christchurch, New Zealand;
authors.forename: Martin
authors.initials: M
authors.lastname: Than
authors.affiliation: Cardiovascular Research Institute Basel (CRIB), Department of Cardiology, and christian.mueller@usb.ch.
authors.forename: Christian
authors.initials: C
authors.lastname: Mueller
mesh_terms: D000465:Algorithms; D005260:Female; D006801:Humans; D057230:Limit of Detection; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood* / Q000401:mortality; D011237:Predictive Value of Tests; D011446:Prospective Studies; D013997:Time Factors; D019210:Troponin I / Q000097:blood*
chemical_list: D019210:Troponin I