Assessment of aortic dissection and hematoma.

Aortic dissection and aortic intramural hematoma are highly lethal diseases occurring mostly in patients with arterial hypertension or Marfan syndrome. Transesophageal echocardiography (TEE) is the diagnostic imaging procedure of choice in the unstable patient. Hallmarks of dissection are the presence of an intimal membrane, or flap, dividing a true and a false lumen, entry and reentry tears, periaortic hematoma, pericardial effusion or tamponade, and aortic regurgitation in dissection of the ascending aorta. TEE allows detection of involvement of the ascending aorta, which places the patient in an extremely high-risk group and necessitates urgent operation. The accuracy of TEE is similar to computed tomography and magnetic resonance imaging, with the added benefit of being feasible at the bedside or in the operating room. Precautions have to be taken during TEE to avoid an abrupt rise in blood pressure. Aortic intramural hematoma is often a precursor of classic dissection or accompanies it and can also be diagnosed by TEE, although the diagnosis is frequently difficult.