title: Prognostic utility of the acute cardiac ischemia time-insensitive predictive instrument (ACI-TIPI).
abstract: BACKGROUND
  We sought to evaluate the test characteristics of the acute cardiac ischemia time-insensitive predictive instrument (ACI-TIPI) in relation to 30-day major adverse cardiac events (MACE) among patients who presented to the Emergency Department with symptoms suggestive of an acute coronary syndrome. We then examined the test characteristics of various dichotomous ACI-TIPI cut points.
  
  
  METHODS
  We prospectively recruited a cohort of Emergency Department (ED) patients with acute chest pain at two urban university hospitals between June and September 2006. Upon enrollment, baseline demographics and cardiac risk factors were collected. An electrocardiogram (ECG) was performed and analyzed with the built-in ACI-TIPI multiple regression model software. An ACI-TIPI probability score was recorded for each patient. Diagnostic test characteristics of ACI-TIPI for MACE (non-ST elevation myocardial infarction (NSTEMI), percutaneous coronary intervention, coronary artery bypass grafting, and all-cause mortality) within 30 days were determined.
  
  
  RESULTS
  Of 144 patients enrolled (mean age 59.1 ± 14.1 years, 59% men), 19 (13%) patients suffered MACE within 30 days. Receiver-operating characteristics (ROC) for ACI-TIPI yielded a c-statistic of 0.69 (95% CI 0.59-0.80, p < 0.01). An ACI-TIPI score of ≥ 20 had 100% sensitivity (95% CI 82-100), 100% negative predictive value (95% CI 86-100), and 21% specificity (14-31%).
  
  
  CONCLUSIONS
  These preliminary results suggest that, while ACI-TIPI has limited discriminatory value for MACE overall, a score of < 20 may have 30-day prognostic utility to allow for safe outpatient management in patients with acute chest pain.
authors.affiliation: Division of Emergency Medicine, University of Washington School of Medicine, Harborview Medical Centre, 325 9th Avenue, Box 325709, Seattle, WA 98104, USA. ilgen@uw.edu.
authors.forename: Jonathan S
authors.initials: JS
authors.lastname: Ilgen
authors.forename: Alex F
authors.initials: AF
authors.lastname: Manini
authors.forename: Udo
authors.initials: U
authors.lastname: Hoffmann
authors.forename: Vicki E
authors.initials: VE
authors.lastname: Noble
authors.forename: Ediza
authors.initials: E
authors.lastname: Giraldez
authors.forename: Supapan
authors.initials: S
authors.lastname: Nualpring
authors.forename: J Stephen
authors.initials: JS
authors.lastname: Bohan