title: Ability of troponin I to predict cardiac events in patients admitted from the emergency department.
abstract: OBJECTIVE
  We sought to determine the predictive ability of troponin I (TnI) in a heterogeneous group of patients with chest pain admitted from the emergency department (ED) for exclusion of myocardial infarction (MI).
  
  
  BACKGROUND
  Previous studies in high-risk patients demonstrated that troponin elevations are associated with increased cardiac events. Little information is available on its predictive ability in more heterogeneous, lower risk patients.
  
  
  METHODS
  Consecutive patients admitted from the ED for possible MI underwent serial myocardial marker sampling of TnI and creatine kinase, CK-MB over an 8-h period. Patients with ST segment elevation were excluded. End points included MI, death, significant complications (e.g., cardiac or respiratory arrest, intra-aortic balloon pump, pulmonary artery catheter or pacemaker placement, revascularization or inotropic infusion) and significant disease.
  
  
  RESULTS
  Events occurred in 513 (27%) of the 1,929 patients evaluated: MI in 175 (9.1%) and death in 34 (1.8%); an additional 248 patients (13%) without MI had complications, and 323 (17%) without MI had significant disease. Sensitivity of TnI for MI was high (96%). Patients without MI who were TnI-positive were more likely to have complications (43% vs. 12%) or significant disease (41% vs. 17%) as compared with those who were TnI-negative; however, the sensitivity of TnI for these two end points was low (14% and 21%, respectively). Predictive values were unchanged after excluding patients with ischemic electrocardiograms.
  
  
  CONCLUSIONS
  Troponin I had a high sensitivity for MI when used as part of a rapid rule-in protocol; however, the sensitivity for other end points was low. Use of TnI alone failed to identify the majority of patients who had either significant disease or complications.
authors.affiliation: Department of Internal Medicine, Medical College of Virginia, Hospitals of Virginia, Commonwealth University, Richmond, USA. mkontos@hsc.vcu.edu
authors.forename: M C
authors.initials: MC
authors.lastname: Kontos
authors.forename: F P
authors.initials: FP
authors.lastname: Anderson
authors.forename: R
authors.initials: R
authors.lastname: Alimard
authors.forename: J P
authors.initials: JP
authors.lastname: Ornato
authors.forename: J L
authors.initials: JL
authors.lastname: Tatum
authors.forename: R L
authors.initials: RL
authors.lastname: Jesse
mesh_terms: D015415:Biomarkers / Q000097:blood; D004636:Emergency Service, Hospital; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009203:Myocardial Infarction / Q000097:blood / Q000150:complications / Q000175:diagnosis*; D011237:Predictive Value of Tests; D012372:ROC Curve; D012680:Sensitivity and Specificity; D019210:Troponin I / Q000032:analysis*
chemical_list: D015415:Biomarkers; D019210:Troponin I