title: A clinical prediction rule for early discharge of patients with chest pain.
abstract: OBJECTIVE
  Current risk stratification tools do not identify very-low-risk patients who can be safely discharged without prolonged emergency department (ED) observation, expensive rule-out protocols, or provocative testing. We seek to develop a clinical prediction rule applicable within 2 hours of ED arrival that would miss fewer than 2% of acute coronary syndrome patients and allow discharge within 2 to 3 hours for at least 30% of patients without acute coronary syndrome.
  
  
  METHODS
  This prospective, cohort study enrolled consenting eligible subjects at least 25 years old at a single site. At 30 days, investigators assigned a diagnosis of acute coronary syndrome or no acute coronary syndrome according to predefined explicit definitions. A recursive partitioning model included risk factors, pain characteristics, physical and ECG findings, and cardiac marker results.
  
  
  RESULTS
  Of 769 patients studied, 77 (10.0%) had acute myocardial infarction and 88 (11.4%) definite unstable angina. We derived a clinical prediction rule that was 98.8% sensitive and 32.5% specific. Patients have very low risk of acute coronary syndrome if they have a normal initial ECG, no previous ischemic chest pain, and age younger than 40 years. In addition, patients at least 40 years old and with a normal ECG result, no previous ischemic chest pain, and low-risk pain characteristics have very low risk if they have an initial creatine kinase-MB (CK-MB) less than 3.0 microg/L or an initial CK-MB greater than or equal to 3.0 microg/L but no ECG or serum-marker increase at 2 hours.
  
  
  CONCLUSIONS
  The Vancouver Chest Pain Rule for early discharge defines a group of patients who can be safely discharged after a brief evaluation in the ED. Prospective validation is needed.
authors.affiliation: The Center for Health Evaluation and Outcome Sciences, University of British Columbia, St. Paul's Hospital, Vancouver, British Columbia, Canada. jimchris@interchange.ubc.ca
authors.forename: Jim
authors.initials: J
authors.lastname: Christenson
authors.forename: Grant
authors.initials: G
authors.lastname: Innes
authors.forename: Douglas
authors.initials: D
authors.lastname: McKnight
authors.forename: Christopher R
authors.initials: CR
authors.lastname: Thompson
authors.forename: Hubert
authors.initials: H
authors.lastname: Wong
authors.forename: Eugenia
authors.initials: E
authors.lastname: Yu
authors.forename: Barb
authors.initials: B
authors.lastname: Boychuk
authors.forename: Eric
authors.initials: E
authors.lastname: Grafstein
authors.forename: Frances
authors.initials: F
authors.lastname: Rosenberg
authors.forename: Kenneth
authors.initials: K
authors.lastname: Gin
authors.forename: Aslam
authors.initials: A
authors.lastname: Anis
authors.forename: Joel
authors.initials: J
authors.lastname: Singer
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D000789:Angina, Unstable / Q000175:diagnosis; D002637:Chest Pain / Q000175:diagnosis* / Q000209:etiology; D015331:Cohort Studies; D003661:Decision Support Techniques; D003937:Diagnosis, Differential; D004635:Emergency Medicine / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000150:complications / Q000175:diagnosis; D010043:Outcome and Process Assessment, Health Care; D010351:Patient Discharge; D011237:Predictive Value of Tests; D011446:Prospective Studies; D018570:Risk Assessment / Q000379:methods; D012307:Risk Factors