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2256 pages added, reviewed or updated during the last month (last updated: 21/4/2021)


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investigations

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No single investigation is entirely suitable.  

  • ECG & chest x-ray -
    • although chest radiography and electrocardiography are carried out in the emergency care settings in patients with chest pain, these tests cannot establish or exclude aortic dissection:
    • ECG
      • is useful to exclude myocardial infarction (infarction may also be excluded by the absence of changes in cardiac enzymes)
      • in about 20% of type A dissections, ischemic changes on the ECG may be present due to extension of the dissection into a coronary ostium (2)
    • chest x-ray -
      • abnormalities in >80% of cases - the most significant being abnormal aortic contour or widening of the aortic silhouette
      • normal x-ray does not exclude the presence of dissection (1).
  • D-dimer levels
    • are elevated in acute aortic dissection and levels below 500 ng/ml within the first 24 hours of symptom onset can exclude acute dissection (negative likelihood ratio of 0.07)
    • further studies are necessary to determine the role of D-dimer assays in acute aortic syndromes (1,2)
  • echocardiography
    • is valuable for making rapid diagnosis at the bedside.
    • a meta-analysis of cohort studies found that transoesophageal echocardiography has a high degree of sensitivity and specificity (1)
    • dissection is confirmed by the demonstration of two channels with differential flow between them, and an intimal flap
    • abnormal doppler flow patterns in the left ventricular outflow tract during diastole or diastolic fluttering of the anterior mitral valve leaflet support the diagnosis.
  • CT
    • contrast CT is the most commonly used modality
    • may provide information about the location, size and the extent of the disease and demonstrate the intimal flap
    • not appropriate in haemodynamically unstable patients
    • European Society of Cardiology  recommends Multidetector computed tomography angiography as the first line of investigation in suspected acute dissection
  • MRI
    • may be used in a stable patient
    • useful for long term surveillance of treated dissection and for the assessment of stable patients presenting with chronic dissection
  • retrograde aortography - historically considered as the gold standard for diagnosis, nowadays rarely performed (1,2)

Note:

  • majority of patients require more than one non-invasive imaging test
  • a cross sectional study (carried out in in 464 patients) reported the following as the initial investigation:
    • CT angigrapgy - in 61% of cases
    • echocardiography - in 33% cases
    • aortography - in 4% cases
    • magnetic resonance angiography - in 2% cases (1)

.Reference:

Last reviewed 01/2018

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