title: CT angiography for safe discharge of patients with possible acute coronary syndromes.
abstract: BACKGROUND
  Admission rates among patients presenting to emergency departments with possible acute coronary syndromes are high, although for most of these patients, the symptoms are ultimately found not to have a cardiac cause. Coronary computed tomographic angiography (CCTA) has a very high negative predictive value for the detection of coronary disease, but its usefulness in determining whether discharge of patients from the emergency department is safe is not well established.
  
  
  METHODS
  We randomly assigned low-to-intermediate-risk patients presenting with possible acute coronary syndromes, in a 2:1 ratio, to undergo CCTA or to receive traditional care. Patients were enrolled at five centers in the United States. Patients older than 30 years of age with a Thrombolysis in Myocardial Infarction risk score of 0 to 2 and signs or symptoms warranting admission or testing were eligible. The primary outcome was safety, assessed in the subgroup of patients with a negative CCTA examination, with safety defined as the absence of myocardial infarction and cardiac death during the first 30 days after presentation.
  
  
  RESULTS
  We enrolled 1370 subjects: 908 in the CCTA group and 462 in the group receiving traditional care. The baseline characteristics were similar in the two groups. Of 640 patients with a negative CCTA examination, none died or had a myocardial infarction within 30 days (0%; 95% confidence interval [CI], 0 to 0.57). As compared with patients receiving traditional care, patients in the CCTA group had a higher rate of discharge from the emergency department (49.6% vs. 22.7%; difference, 26.8 percentage points; 95% CI, 21.4 to 32.2), a shorter length of stay (median, 18.0 hours vs. 24.8 hours; P<0.001), and a higher rate of detection of coronary disease (9.0% vs. 3.5%; difference, 5.6 percentage points; 95% CI, 0 to 11.2). There was one serious adverse event in each group.
  
  
  CONCLUSIONS
  A CCTA-based strategy for low-to-intermediate-risk patients presenting with a possible acute coronary syndrome appears to allow the safe, expedited discharge from the emergency department of many patients who would otherwise be admitted. (Funded by the Commonwealth of Pennsylvania Department of Health and the American College of Radiology Imaging Network Foundation; ClinicalTrials.gov number, NCT00933400.).
authors.affiliation: Department of Radiology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA. harold.litt@uphs.upenn.edu
authors.forename: Harold I
authors.initials: HI
authors.lastname: Litt
authors.forename: Constantine
authors.initials: C
authors.lastname: Gatsonis
authors.forename: Brad
authors.initials: B
authors.lastname: Snyder
authors.forename: Harjit
authors.initials: H
authors.lastname: Singh
authors.forename: Chadwick D
authors.initials: CD
authors.lastname: Miller
authors.forename: Daniel W
authors.initials: DW
authors.lastname: Entrikin
authors.forename: James M
authors.initials: JM
authors.lastname: Leaming
authors.forename: Laurence J
authors.initials: LJ
authors.lastname: Gavin
authors.forename: Charissa B
authors.initials: CB
authors.lastname: Pacella
authors.forename: Judd E
authors.initials: JE
authors.lastname: Hollander
mesh_terms: D054058:Acute Coronary Syndrome / Q000000981:diagnostic imaging* / Q000401:mortality; D000328:Adult; D000368:Aged; D016001:Confidence Intervals; D017023:Coronary Angiography / Q000379:methods; D003327:Coronary Disease / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000628:therapy; D005260:Female; D006295:Health Resources / Q000706:statistics & numerical data; D006760:Hospitalization; D006801:Humans; D007902:Length of Stay; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000453:epidemiology; D010351:Patient Discharge; D014057:Tomography, X-Ray Computed