title: Coronary computed tomographic angiography for rapid discharge of low-risk patients with potential acute coronary syndromes.
abstract: OBJECTIVE
  Coronary computed tomographic (CT) angiography has excellent performance characteristics relative to coronary angiography and exercise or pharmacologic stress testing. We hypothesize that coronary CT angiography can identify a cohort of emergency department (ED) patients with a potential acute coronary syndrome who can be safely discharged with a less than 1% risk of 30-day cardiovascular death or nonfatal myocardial infarction.
  
  
  METHODS
  We conducted a prospective cohort study at an urban university hospital ED that enrolled consecutive patients with potential acute coronary syndromes and a low TIMI risk score who presented to the ED with symptoms suggestive of a potential acute coronary syndrome and received a coronary CT angiography. Our intervention was either immediate coronary CT angiography in the ED or after a 9- to 12-hour observation period that included cardiac marker determinations, depending on time of day. The main clinical outcome was 30-day cardiovascular death or nonfatal myocardial infarction.
  
  
  RESULTS
  Five hundred sixty-eight patients with potential acute coronary syndrome were evaluated: 285 of these received coronary CT angiography immediately in the ED and 283 received coronary CT angiography after a brief observation period. Four hundred seventy-six (84%) were discharged home after coronary CT angiography. During the 30-day follow-up period, no patients died of a cardiovascular event (0%; 95% confidence interval [CI] 0% to 0.8%) or sustained a nonfatal myocardial infarction (0%; 95% CI 0 to 0.8%).
  
  
  CONCLUSIONS
  ED patients with symptoms concerning for a potential acute coronary syndrome with a low TIMI risk score and a nonischemic initial ECG result can be safely discharged home after a negative coronary CT angiography test result.
authors.affiliation: Department of Emergency Medicine, Hospital of the University of Pennsylvania, Philadelphia, PA 19104-4283, USA.
authors.forename: Judd E
authors.initials: JE
authors.lastname: Hollander
authors.forename: Anna Marie
authors.initials: AM
authors.lastname: Chang
authors.forename: Frances S
authors.initials: FS
authors.lastname: Shofer
authors.forename: Christine M
authors.initials: CM
authors.lastname: McCusker
authors.forename: William G
authors.initials: WG
authors.lastname: Baxt
authors.forename: Harold I
authors.initials: HI
authors.lastname: Litt
mesh_terms: D054058:Acute Coronary Syndrome / Q000000981:diagnostic imaging* / Q000401:mortality / Q000503:physiopathology; D000328:Adult; D002637:Chest Pain / Q000175:diagnosis; D017023:Coronary Angiography / Q000379:methods*; D023921:Coronary Stenosis / Q000000981:diagnostic imaging; D004562:Electrocardiography; D004636:Emergency Service, Hospital; D005260:Female; D006334:Heart Function Tests; D006801:Humans; D007902:Length of Stay; D008297:Male; D008875:Middle Aged; D018570:Risk Assessment; D014057:Tomography, X-Ray Computed; D014218:Triage