title: Computed tomographic coronary artery calcium assessment for evaluating chest pain in the emergency department: long-term outcome of a prospective blind study.
abstract: OBJECTIVE
  To determine the long-term outcome of computed tomographic (CT) quantification of coronary artery calcium (CAC) used as a triage tool for patients presenting with chest pain to an emergency department (ED).
  
  
  METHODS
  Patients (men aged 30-62 years and women aged 30-65 years) with chest pain and low-to-moderate probability of coronary artery disease underwent both conventional ED chest pain evaluation and CT CAC assessment prospectively. Patients' physicians were blinded to the CAC results. The results of the conventional evaluation were compared with CAC findings on CT, and the long-term outcome in patients undergoing CT CAC assessment was established. Primary end points (acute coronary syndrome, death, fatal or nonfatal non-ST-segment elevation myocardial infarction, fatal or nonfatal ST-segment elevation myocardial infarction) and secondary outcomes (coronary artery bypass grafting, percutaneous transluminal coronary angioplasty, coronary stenting, or a combination thereof) were obtained when the patient was dismissed from the ED or hospital and then at 30 days, 1 year, and 5 years.
  
  
  RESULTS
  Of the 263 study patients, 133 (51%) had a CAC score of zero. This absence of CAC correlated strongly with the likelihood of noncardiac chest pain. Among 133 patients with a CAC score of zero, only 1 (<1%) had cardiac chest pain. Conversely, of the 31 patients shown to have cardiac chest pain, 30 (97%) had evidence of CAC on CT. When a CAC cutoff score of 36 was used, as suggested by receiver operating characteristic analysis, sensitivity was 90%; specificity, 85%; positive predictive value, 44%; and negative predictive value, 99%. During long-term follow-up, patients without CAC experienced no cardiac events at 30 days, 1 year, and 5 years.
  
  
  CONCLUSIONS
  Findings suggest that CT CAC assessment is a powerful adjunct in chest pain evaluation for the population at low-to-intermediate risk. Absent or minimal CAC in this population makes cardiac chest pain extremely unlikely. The absence of CAC suggests an excellent long-term (5-year) prognosis, with no primary or secondary cardiac outcomes occurring in study patients at 5-year follow-up.
authors.affiliation: Department of Emergency Medicine, Mayo Clinic, 200 First St SW, Rochester, MN 55905, USA. laudon.dennis@mayo.edu
authors.forename: Dennis A
authors.initials: DA
authors.lastname: Laudon
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Behrenbeck
authors.forename: Christina M
authors.initials: CM
authors.lastname: Wood
authors.forename: Kent R
authors.initials: KR
authors.lastname: Bailey
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Callahan
authors.forename: Jerome F
authors.initials: JF
authors.lastname: Breen
authors.forename: Larry F
authors.initials: LF
authors.lastname: Vukov
mesh_terms: D000208:Acute Disease; D000328:Adult; D000368:Aged; D000465:Algorithms; D002114:Calcinosis / Q000175:diagnosis / Q000000981:diagnostic imaging*; D002637:Chest Pain / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000453:epidemiology; D002983:Clinical Competence; D017023:Coronary Angiography / Q000379:methods; D003327:Coronary Disease / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000453:epidemiology; D003937:Diagnosis, Differential; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D017063:Outcome Assessment, Health Care; D011379:Prognosis; D011446:Prospective Studies; D012372:ROC Curve; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D016037:Single-Blind Method; D014057:Tomography, X-Ray Computed / Q000379:methods / Q000706:statistics & numerical data*; D014218:Triage / Q000379:methods*