title: Acute chest pain investigation: utility of cardiac CT angiography in guiding troponin measurement.
abstract: OBJECTIVE
  To assess the impact on length of stay and rate of major adverse cardiovascular events of a cardiac computed tomographic (CT) angiography-guided algorithm to examine patients who present to the emergency department (ED) with low- to intermediate-risk chest pain.
  
  
  METHODS
  The study was approved by the institutional review board, and all patients gave written informed consent. Two hundred three consecutive patients (mean age, 55 years ± 11 [standard deviation]; 123 men) with low- to intermediate-risk ischemic-type chest pain were prospectively enrolled. Patients underwent initial cardiac CT angiography with subsequent treatment determined by reference to findings at cardiac CT angiography; patients without overt plaque were immediately discharged from the hospital, patients with nonobstructive plaque and mild-to-moderate stenoses were discharged after a negative 6-hour troponin level, and patients with severe stenoses were admitted to the hospital. Discharged patients were followed up for a mean of 14.2 months. Additionally, length of stay and safety outcomes among these patients were compared with those in 102 consecutive patients with low- to intermediate-risk chest pain who presented to the ED and underwent a standard of care (SOC) work-up without cardiac CT angiography. One-way analysis of variance with Bonferroni correction was used to compare length of stay between groups.
  
  
  RESULTS
  Cardiac CT angiography findings in the 203 patients who underwent cardiac CT angiography were as follows: Sixty-five (32%) patients had no plaque, 107 (53%) had nonobstructive plaque, and 31 (15%) had severe stenoses. At follow-up, there were no deaths or cases of acute coronary syndrome (cardiac CT angiography, 0%, 95% confidence interval [CI]: 0%, 1.85%; SOC, 0%, 95% CI: 0%, 3.63%), and the rate of readmission to the hospital because of chest pain was higher with the SOC approach (9% vs 1%, P = .01). Mean ED length of stay was lower with cardiac CT angiography (6.62 hours ± 0.38 after a single troponin level and 9.15 hours ± 0.30 after serial troponin levels) than with the SOC approach (11.62 hours ± 0.47, P < .001).
  
  
  CONCLUSIONS
  Tailoring troponin measurement to cardiac CT angiography findings is safe and allows early discharge of patients with low- to intermediate-risk chest pain, resulting in reduced length of stay.
authors.affiliation: Monash Cardiovascular Research Centre, MonashHEART, 246 Clayton Road, Clayton, VIC 3168, Australia.
authors.forename: Arthur
authors.initials: A
authors.lastname: Nasis
authors.forename: Ian T
authors.initials: IT
authors.lastname: Meredith
authors.forename: Nitesh
authors.initials: N
authors.lastname: Nerlekar
authors.forename: James D
authors.initials: JD
authors.lastname: Cameron
authors.forename: Paul R
authors.initials: PR
authors.lastname: Antonis
authors.forename: Philip M
authors.initials: PM
authors.lastname: Mottram
authors.forename: Michael C
authors.initials: MC
authors.lastname: Leung
authors.forename: John M
authors.initials: JM
authors.lastname: Troupis
authors.forename: Marcus
authors.initials: M
authors.lastname: Crossett
authors.forename: Anthony G
authors.initials: AG
authors.lastname: Kambourakis
authors.forename: George
authors.initials: G
authors.lastname: Braitberg
authors.forename: Udo
authors.initials: U
authors.lastname: Hoffmann
authors.forename: Sujith K
authors.initials: SK
authors.lastname: Seneviratne
mesh_terms: D000208:Acute Disease; D000465:Algorithms; D000704:Analysis of Variance; D015415:Biomarkers / Q000097:blood; D002637:Chest Pain / Q000000981:diagnostic imaging* / Q000628:therapy; D016009:Chi-Square Distribution; D017023:Coronary Angiography / Q000379:methods*; D004636:Emergency Service, Hospital; D005260:Female; D006801:Humans; D007902:Length of Stay / Q000706:statistics & numerical data; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D014336:Troponin / Q000097:blood*
chemical_list: D015415:Biomarkers; D014336:Troponin