Aortic dissection

Aortic dissection begins with an intimal tear through which blood tracks into the media. The Stanford classification guides management: type A involves the ascending aorta, type B does not.

Clinical presentation

Abrupt, tearing chest or back pain, often maximal at onset. Pulse or blood pressure differences between arms, a new aortic regurgitation murmur, stroke, limb ischaemia or abdominal pain reflect branch involvement. Hypertension and connective tissue disease are major risk factors.

Radiographic features

CT angiography

• An intimal flap separating true and false lumens
• The false lumen is usually larger and enhances later
• Extension into the arch vessels, coronary, mesenteric, renal or iliac arteries
• Complications: pericardial haemopericardium, rupture, malperfusion

Chest radiograph

May show mediastinal widening or an abnormal aortic contour, but a normal film does not exclude dissection.

Echocardiography

Transoesophageal echo is useful in unstable patients and shows aortic regurgitation and pericardial fluid.

Treatment and prognosis

Type A dissection is a surgical emergency. Uncomplicated type B is managed with blood pressure and heart rate control; complicated type B is treated with endovascular stenting.

Differential diagnosis

• Intramural hematoma
• Penetrating atherosclerotic ulcer
• Motion artefact in the ascending aorta