Coronary artery disease: a normal electron-beam CT makes it less likely

Clinical bottom line (level 2a)

  1. In patients with suspected coronary artery disease, a normal electron beam CT makes obstructive coronary artery disease less likely (LR - 0.15) .
  2. Electron beam CT is not very helpful at diagnosing obstructive coronary artery disease.
Nallamothu et al: Arch Intern Med 2001; 161 : 833-838
Expires February 2004

The study

Systematic review of all diagnostic studies of
  • Patients: suspected coronary artery disease requiring coronary angiography
  • Intervention: electron-beam computed tomography compared with coronary angiography
  • Outcome: obstructive coronary artery disease (> 50% stenosis)

    Articles found in English using Medline, Current Contents, 1979 to February 2000 (search terms: tomography, X-ray computed or tomographic scanncers with exploded term coronary disease ) and and searching bibliographies of retrieved articles, and contacting original authors experts in the field to identified unpublished material

    Selection criteria: see above and below
    Appraisal criteria: by 2 independent reviewers using a standardised form: included comments on blinding, reference standard
    Articles excluded if:
    • unable to determine true-positive, true-negative, false-positive or false-negative rates
    • performed exclusively in patients post-PTCA or CABG
    • findings other than coronary artery calcification used as a positive result
    • incompatible methods used e.g. EBCT angiography or EBCT stress testing
    • studies with > 50% overlap between patients


    14 reports from 9 studies were found involving 1411 patients
    4 studies were found to be significantly heterogeneous. However excluding these studies from the analysis did not significantly alter the results.

    The evidence

    • pooled sensitivity: 92% (95% CI: 91% to 94%)
    • pooled specificty: 51% (95% CI: 48% to 55%)
    • LR + 1.9; LR - 0.15

    Comments

    1. Most studies used > 50% stenosis as the definition of obstructive coronary artery disease.
    2. Only 2 studies reported blinding.

    Citation

    1. Nallamothu BK, Saint S, Bielak LF, et al: electron-beam computed tomography in the diagnosis of coronary artery disease. Arch Intern Med 2001; 161 : 833-838
    Search Terms: ?
    Contributor: Chris Ball, February 2002
    Reviewer:

    Clinical Question.
    Patient suspected coronary artery disease
    Intervention or Exposure electron-beam computed tomography (EBCT)
    Comparison coronary angiography
    Outcome coronary artery disease (> 50% stenosis)
    		•