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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:
- 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)
- 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.
- 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
- 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)
- 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)
Last reviewed 01/2018