Thoracic Imaging 2003 - Society of Thoracic Radiology

Acute Aortic Syndrome
Ernest M. Scalzetti, M.D.
January 2003
Four conceptually distinct but clinically interrelated conditions
of the thoracic aorta.
Aortic Dissection
Pathogenesis
Usually, intimal disruption with dissection of blood in
the aortic media
It is thought that the aortic wall is weakened by medial
degeneration
Clinical features
Risk factors
Males>females, at least 2:1
Most patients also have systemic hypertension
Other predisposing factors: Marfan syndrome, pregnancy,
pre-existing aneurysm, cocaine use, etc.
Presentation
Typical age at presentation:50-70 years
Pain (chest pain, intrascapular back pain)
Hypertension
Unequal extremity blood pressures
"Acute dissection" presents within 2 weeks of onset
of symptoms
Classification based on location, correlates with prognosis
Type A involves ascending aorta
Type B is limited to descending aorta
Treatment
Type A usually managed surgically
Type B usually managed medically
Although the type A dissections are more lethal in the
acute phase,type B dissections can be life-threatening as
well.
Diagnosis: CT and MR features
Intimal flap separating true and false lumen
Extent of involvement
Aortic insufficiency
Patency or involvement of branch vessels
Hemopericardium
Intramural Hematoma
Pathogenesis
Hemorrhage into the aortic media, without an intimal tear
Source of hemorrhage: vasa vasorum
Clinical features
Presentation similar to aortic dissection
Classification similar to aortic dissection
Treatment is controversial; for now, recommendations
are similar to those for aortic dissection
Diagnosis: CT and MR features
Appearance of acute blood in aortic wall
Extent of involvement
Penetrating Atherosclerotic Ulcer
Pathogenesis
Atherosclerosis with ulceration that penetrates the intima
Blood from the aortic lumen has access to the aortic media
May lead to IMH, aortic dissection, pseudoaneurysm or
rupture
Aortic dissection, when it occurs, usually is limited in
extent
Clinical features
Presents with severe chest/back pain of sudden onset
Uncommon presentation: atheroembolism
May be asymptomatic
Pleural effusion may be present
Occurs in elderly hypertensive men
Can involve any portion of the aorta
Most common in mid- and distal descending thoracic aorta
Often involves an ectatic or aneurysmal segment of aorta
May be multiple
Range in diameter from 5-25 mm.
Range in depth from 4-30 mm.
Most can be managed medically
Surgery versus endovascular (stent-graft) therapy
Diagnosis: CT and MR features
Crater-like outpouching from the aortic lumen
Thickened aortic wall
Severe atherosclerosis of the surrounding aorta
Aortic Rupture
Pathogenesis
Traumatic transection
Pre-existing aneurysm, dissection, IMH or penetrating
ulcer
Spontaneous?
Clinical features
Presents with chest/back pain
Usually presents with hemodynamic instability
Site of rupture may be anywhere in thoracic aorta,but in
trauma it usually is in the proximal descending aorta
High mortality without surgical intervention
Diagnosis: CT and MR features
Mediastinal hematoma
Abnormal contours of aortic lumen
Hemothorax may be present
Signs of instability in a partially thrombosed pre-existing
aneurysm
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Khan IA, Nair CK. Clinical,, diagnostic and management perspectives
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Levy JR, Heiken JP, Gutierrez FR. Imaging of penetrating atherosclerotic
ulcers of the aorta. AJR 1999;173:151-4.
Pretre R, Von Segesser LK. Aortic dissection. Lancet
1997;349:1461-64.
Sawhney NS, DeMaria AN, Blanchard DG. Aortic intramural
hematoma: an increasingly recognized and potentially fatal
entity. Chest 2001;120:1340-6.
Troxler M, Mavor AID, Homer-Vanniasinkam S. Penetrating atherosclerotic
ulcers of the aorta. Br J Surg 2001;88:1169-77.
Yokoyama H, et al. Spontaneous rupture of the thoracic aorta.
Ann Thorac Surg 2000;70:683-9.
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