title: A new score for the diagnosis of acute coronary syndrome in acute chest pain with non-diagnostic ECG and normal troponin.
abstract: BACKGROUND
  Acute coronary syndrome (ACS) represents a difficult diagnostic challenge in patients with undifferentiated chest pain. There is a need for a valid clinical score to improve diagnostic accuracy.
  
  
  OBJECTIVE
  To compare the performance of a model combining the Thrombolysis in Myocardial Infarction (TIMI) score and a score describing chest pain (ACS diagnostic score: ACSD score) with that of both scores alone in the diagnosis of ACS in ED patients with chest pain associated with a non-diagnostic ECG and normal troponin.
  
  
  METHODS
  In this observational cohort study, we enrolled 809 patients admitted to a chest pain unit with normal ECG and normal troponin. They were prospectively evaluated in order to calculate TIMI score, chest pain characteristics score and ACSD score. Diagnosis of ACS was the primary outcome and defined on the basis of 2 cardiologists after reviewing the patient medical records and follow-up data. Mortality and major cardiovascular events were followed for 1 month for patients discharged directly from ED. Discriminative power of scores was evaluated by the area under the ROC curve.
  
  
  RESULTS
  ACS was confirmed in 90 patients (11.1%). The area under the ROC curve for ACSD score was 0.85 (95% CI 0.80 to 0.90) compared with 0.74 (95% CI 0.67 to 0.81) for TIMI and 0.79 (95% CI 0.74 to 0.84) for chest pain characteristics score. A threshold value of 9 appeared to optimise sensitivity (92%) and negative predictive value (99%) without excessively compromising specificity (62%) and positive predictive value (23%).
  
  
  CONCLUSIONS
  The ACSD score showed a good discrimination performance and an excellent negative predictive value which allows safely ruling out ACS in ED patients with undifferentiated chest pain. Our findings should be validated in a larger multicentre study.
authors.affiliation: Emergency Department and Research Laboratory (LR12SP18), Fattouma Bourguiba University Hospital, Monastir, Tunisia Faculty of Medicine, University of Monastir, Monastir, Tunisia.
authors.forename: Hamdi
authors.initials: H
authors.lastname: Boubaker
authors.affiliation: Emergency Department and Research Laboratory (LR12SP18), Fattouma Bourguiba University Hospital, Monastir, Tunisia Faculty of Medicine, University of Monastir, Monastir, Tunisia.
authors.forename: Mohamed Habib
authors.initials: MH
authors.lastname: Grissa
authors.affiliation: Emergency Department and Research Laboratory (LR12SP18), Fattouma Bourguiba University Hospital, Monastir, Tunisia Faculty of Medicine, University of Monastir, Monastir, Tunisia.
authors.forename: Kaouther
authors.initials: K
authors.lastname: Beltaief
authors.affiliation: Emergency Department and Research Laboratory (LR12SP18), Fattouma Bourguiba University Hospital, Monastir, Tunisia.
authors.forename: Mohamed Haj
authors.initials: MH
authors.lastname: Amor
authors.affiliation: Emergency Department and Research Laboratory (LR12SP18), Fattouma Bourguiba University Hospital, Monastir, Tunisia Faculty of Medicine, University of Monastir, Monastir, Tunisia.
authors.forename: Zouhaier
authors.initials: Z
authors.lastname: Mdimagh
authors.affiliation: Emergency Department and Research Laboratory (LR12SP18), Fattouma Bourguiba University Hospital, Monastir, Tunisia.
authors.forename: Amor
authors.initials: A
authors.lastname: Boukhris
authors.affiliation: Emergency Department, Moknine Hospital, Moknine, Tunisia.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Ben Amor
authors.affiliation: Faculty of Medicine, University of Monastir, Monastir, Tunisia Department of Cardiology, Fattouma Bourguiba University Hospital, Monastir, Tunisia.
authors.forename: Zohra
authors.initials: Z
authors.lastname: Dridi
authors.affiliation: Faculty of Medicine, University of Monastir, Monastir, Tunisia Department of Preventive Epidemiology, Fattouma Bourguiba University Hospital, Monastir, Tunisia.
authors.forename: Mondher
authors.initials: M
authors.lastname: Letaief
authors.affiliation: Emergency Department and Research Laboratory (LR12SP18), Fattouma Bourguiba University Hospital, Monastir, Tunisia Faculty of Medicine, University of Monastir, Monastir, Tunisia.
authors.forename: Wahid
authors.initials: W
authors.lastname: Bouida
authors.affiliation: Emergency Department and Research Laboratory (LR12SP18), Fattouma Bourguiba University Hospital, Monastir, Tunisia Faculty of Medicine, University of Monastir, Monastir, Tunisia.
authors.forename: Riadh
authors.initials: R
authors.lastname: Boukef
authors.affiliation: Biochemical Laboratory, Fattouma Bourguiba University Hospital, Monastir, Tunisia.
authors.forename: Fadhel
authors.initials: F
authors.lastname: Najjar
authors.affiliation: Emergency Department and Research Laboratory (LR12SP18), Fattouma Bourguiba University Hospital, Monastir, Tunisia Faculty of Medicine, University of Monastir, Monastir, Tunisia.
authors.forename: Semir
authors.initials: S
authors.lastname: Nouira
mesh_terms: D054058:Acute Coronary Syndrome / Q000097:blood / Q000175:diagnosis*; D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood; D002637:Chest Pain / Q000175:diagnosis*; D004562:Electrocardiography; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis; D011446:Prospective Studies; D012372:ROC Curve; D018570:Risk Assessment; D012307:Risk Factors; D012680:Sensitivity and Specificity; D014336:Troponin / Q000097:blood*
chemical_list: D015415:Biomarkers; D014336:Troponin