title: Development of a clinical prediction rule for 30-day cardiac events in emergency department patients with chest pain and possible acute coronary syndrome.
abstract: OBJECTIVE
  Evaluation of emergency department (ED) patients with chest pain who are at low risk for acute coronary syndrome is resource intensive and may lead to false-positive test results and unnecessary downstream procedures. We seek to identify patients at low short-term risk for a cardiac event for whom additional ED investigations might be unnecessary.
  
  
  METHODS
  We prospectively enrolled patients older than 24 years and with a primary complaint of chest pain from 3 academic EDs. Physicians completed standardized data collection forms before diagnostic testing. The primary adjudicated outcome was acute myocardial infarction, revascularization, or death of cardiac or unknown cause within 30 days. We used recursive partitioning to derive the rule and validated the model with 5,000 bootstrap replications.
  
  
  RESULTS
  Of 2,718 patients enrolled, 336 (12%) experienced a cardiac event within 30 days (6% acute myocardial infarction, 10% revascularization, 0.2% death). We developed a rule consisting of the absence of 5 predictors: ischemic ECG changes not known to be old, history of coronary artery disease, pain typical for acute coronary syndrome, initial or 6-hour troponin level greater than the 99th percentile, and age greater than 50 years. Patients aged 40 years or younger required only a single troponin evaluation. The rule was 100% sensitive (95% confidence interval 97.2% to 100.0%) and 20.9% specific (95% confidence interval 16.9% to 24.9%) for a cardiac event within 30 days.
  
  
  CONCLUSIONS
  This clinical prediction rule identifies ED chest pain patients at very low risk for a cardiac event who may be suitable for discharge. A prospective multicenter study is needed to validate the rule and determine its effect on practice.
authors: Department of Emergency Medicine, Division of Emergency Medicine Research, Mayo Clinic College of Medicine, Rochester, MN, USA. hess.erik@mayo.edu
authors: Erik P
authors: EP
authors: Hess
authors: Robert J
authors: RJ
authors: Brison
authors: Jeffrey J
authors: JJ
authors: Perry
authors: Lisa A
authors: LA
authors: Calder
authors: Venkatesh
authors: V
authors: Thiruganasambandamoorthy
authors: Dipti
authors: D
authors: Agarwal
authors: Annie T
authors: AT
authors: Sadosty
authors: Marco L A
authors: ML
authors: Silvilotti
authors: Allan S
authors: AS
authors: Jaffe
authors: Victor M
authors: VM
authors: Montori
authors: George A
authors: GA
authors: Wells
authors: Ian G
authors: IG
authors: Stiell
mesh_terms: D000046:Academic Medical Centers / Q000706:statistics & numerical data; D054058:Acute Coronary Syndrome / Q000175:diagnosis* / Q000401:mortality; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D002637:Chest Pain / Q000175:diagnosis* / Q000401:mortality; D003324:Coronary Artery Disease / Q000453:epidemiology; D003661:Decision Support Techniques; D004562:Electrocardiography; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis / Q000453:epidemiology; D009204:Myocardial Revascularization / Q000706:statistics & numerical data; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D020107:Troponin T / Q000097:blood
chemical_list: D020107:Troponin T