Thoracic Aortic Aneurysm

KEY FEATURES

ESSENTIALS OF DIAGNOSIS

• Ascending aortic diameter > 4 cm on imaging study

• Descending aortic diameter > 3.5 cm on imaging study

GENERAL CONSIDERATIONS

• Ascending aortic aneurysms usually fall into 1 of 3 patterns:

  1. Supracoronary sinus dilatation

  2. Annuloaortic ectasia (Marfan’s syndrome)

  3. Diffuse tubular enlargement

• Descending aortic aneurysm are classified into 4 types (Crawford classification):

  1. Thoracic and upper abdominal aorta

  2. Entire thoracic and abdominal aorta

  3. Lower thoracic and abdominal

  4. Predominantly abdominal

• Aortic aneurysms are often familial (eg, Marfan’s syndrome)

• Aortic aneurysms grow about 1 mm/year and grow faster in the descending aorta compared with the ascending aorta

• As the aorta enlarges, rupture becomes more likely in an exponential fashion with the rapid acceleration point of the curve at 6 cm for the ascending aorta and 7 cm for the descending aorta

CLINICAL PRESENTATION

SYMPTOMS AND SIGNS

• Generally no symptoms until rupture or dissection occurs

• Deep visceral pain in upper anterior chest or back

• Possible dysphagia or stridor

PHYSICAL EXAM FINDINGS

• Possible aortic regurgitation murmur

• Signs of Marfan’s syndrome

• Rarely, anterior upper chest wall pulsations

DIFFERENTIAL DIAGNOSIS

• Aortic dissection

• Aortic rupture with contained hematoma

• Mediastinal or thoracic tumor

DIAGNOSTIC EVALUATION

IMAGING STUDIES

• Chest x-ray: thoracic aortic aneurysms are almost always visible

• CT or MRI: defines the aortic anatomy very well

DIAGNOSTIC PROCEDURES

• Aortography is rarely used today

TREATMENT

CARDIOLOGY REFERRAL

• Significant aortic regurgitation

• Suspected cardiac disease

HOSPITALIZATION CRITERIA

• Pain likely from aneurysm

• Planned surgery

THERAPEUTIC PROCEDURES

• Endoluminal stent grafts are an alternative in selected cases

SURGERY

• Surgical replacement with a synthetic graft is considered in asymptomatic patients at the following diameters:

  Table Graphic Jump Location

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  	Non-Marfan’s	Marfan’s
  Ascending	5.0 cm	5.5 cm
  Descending	6.0 cm	6.5 cm

• Symptomatic aneurysms (pain, impingement on other structures) need immediate replacement

MONITORING

• ECG monitoring in hospital as appropriate

DIET AND ACTIVITY

• Restricted activity in symptomatic patients until surgery is completed

• Asymptomatic patients should not do major weight lifting

ONGOING MANAGEMENT

HOSPITAL DISCHARGE CRITERIA

• Resolution of problem

• Successful surgery

FOLLOW-UP

• Stable, asymptomatic patients should have repeat imaging every 2 years

• New patients with moderately large aneurysms should be imaged in 3–6 months; if stable in 1 year, ...