AoD Evaluation: screening and imaging
Thoracic aortic diseases are usually asymptomatic and not easily detectable until an acute and often catastrophic complication occurs.
Imaging of the thoracic aorta with computed tomographic imaging (CT), magnetic resonance imaging (MR), or in some cases, echocardiographic examination is the only method to detect thoracic aortic diseases.
Recommendations for screening tests and diagnostic imaging studies during the initial evaluation of acute thoracic aortic disease are presented below.
Recommendations for screening tests
- An electrocardiogram should be obtained on all patients who present with symptoms that may represent acute thoracic aortic dissection.
- Given the relative infrequency of dissection-related coronary artery occlusion, the presence of ST-segment elevation suggestive of myocardial infarction should be treated as a primary cardiac event without delay for definitive aortic imaging unless the patient is at high risk for aortic dissection. (LOE: B)
- The role of chest x-ray in the evaluation of possible thoracic aortic disease should be directed by the patient’s pretest risk of disease as follows:
- Intermediate risk: Chest x-ray should be performed on all intermediate-risk patients, as it may establish a clear alternate diagnosis that obviates the need for definitive aortic imaging. (LOE: C)
- Low risk: Chest x-ray should be performed on all low-risk patients, as it may either establish an alternative diagnosis or demonstrate findings that are suggestive of thoracic aortic disease, indicating the need for urgent definitive aortic imaging. (LOE: C)
- Urgent and definitive imaging of the aorta using transesophageal echocardiogram, computed tomographic imaging, or magnetic resonance imaging is recommended to identify or exclude thoracic aortic dissection in patients at high risk for the disease by initial screening. (LOE: B)
- A negative chest x-ray should not delay definitive aortic imaging in patients determined to be high risk for aortic dissection by initial screening. (LOE: C)
Recommendations for diagnostic imaging studies
- Selection of a specific imaging modality to identify or exclude aortic dissection should be based on patient variables and institutional capabilities, including immediate availability. (LOE: C)
- If a high clinical suspicion exists for acute aortic dissection, but initial aortic imaging is negative, a second imaging study should be obtained. (LOE:C)