title: Prospective evaluation of a simplified risk stratification tool for patients with chest pain in an emergency department observation unit.
abstract: BACKGROUND
  The Thrombolysis in Myocardial Infarction score has been validated as a risk stratification tool in the emergency department (ED) setting, but certain aspects of the scoring system may not be applicable when applied to patients with chest pain selected for ED observation unit (EDOU) stay. We evaluated a simplified, 3-point risk stratification tool for patients in EDOU, which we termed the CARdiac score: Coronary disease [previous myocardial infarction (MI), stent, or coronary artery bypass graft (CABG)], Age (65 years or older), and Risk factors (at least 3 of 5 cardiac risk factors).
  
  
  METHODS
  We performed a prospective, observational study with 30-day phone follow-up for all patients with chest pain admitted to our EDOU over a 36-month period. Baseline data, outcomes related to EDOU stay, inpatient admission, and 30-day outcomes were recorded. CARdiac scores were calculated based on patient history and were used to evaluate the risk of the composite outcome of MI, stent/CABG, or death during the EDOU stay. CARdiac scores were also used to evaluate the risk of inpatient admission. The CARdiac score was not used during the EDOU stay and was calculated blinding to patient outcomes.
  
  
  RESULTS
  One thousand two hundred seventy-six patients were evaluated. Average age was 54.1 years (18-92 years) and 46% were male. Forty patients experienced composite outcomes: stent (32), CABG (4), MI and stent (2), MI and CABG (1), and MI (1). Risk of the composite outcome generally increased by CARdiac score: 0 (1.5%), 1 (3.6%), 2 (9%), and 3 (5.4%). Patients with a CARdiac score of 2 or 3 (moderate risk) were significantly more likely to experience MI, stent, or CABG than those with a score of 0 or 1 (low risk): 16/193 moderate-risk patients (8.3%) had the composite outcome versus 24/1083 low-risk patients (2.2%, P < 0.001, relative risk = 3.8). Those at moderate risk by the CARdiac score were also more likely to require inpatient admission from the EDOU (17.6% vs. 9.8%, P < 0.001).
  
  
  CONCLUSIONS
  The CARdiac score may prove to be a simple tool for risk stratification of patients with chest pain in an EDOU. Patients at moderate risk by CARdiac score may be appropriate for more intensive evaluation in the EDOU or consideration for inpatient admission rather than EDOU placement.
authors.affiliation: Division of Emergency Medicine, University of Utah, 50 N. Medical Dr, Salt Lake City, UT 84132, USA. matthew.fuller@hsc.utah.edu
authors.forename: Matthew
authors.initials: M
authors.lastname: Fuller
authors.forename: David
authors.initials: D
authors.lastname: Hamilton
authors.forename: Jessica
authors.initials: J
authors.lastname: Holly
authors.forename: Michael
authors.initials: M
authors.lastname: Mallin
authors.forename: Thomas
authors.initials: T
authors.lastname: Rayner
authors.forename: Nathan
authors.initials: N
authors.lastname: Eshenroder
authors.forename: Erik
authors.initials: E
authors.lastname: Barton
authors.forename: Troy
authors.initials: T
authors.lastname: Madsen
mesh_terms: D054058:Acute Coronary Syndrome / Q000150:complications / Q000175:diagnosis*; D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D002637:Chest Pain / Q000209:etiology*; D003920:Diabetes Mellitus; D004636:Emergency Service, Hospital; D005260:Female; D006757:Hospital Units; D006801:Humans; D006949:Hyperlipidemias; D006973:Hypertension; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000150:complications / Q000175:diagnosis*; D011446:Prospective Studies; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D012907:Smoking; D055815:Young Adult