Thoracic Aortic Aneurysms

KEY FEATURES

Essentials of Diagnosis

• Widened mediastinum on chest radiograph

• With rupture, sudden onset chest pain radiating to the back

General Considerations

• Aneurysms of the thoracic aorta account for < 10% of aortic aneurysms

• Causes

  • Atherosclerosis

  • Trauma

  • Syphilis (rare)

  • Ehlers-Danlos and Marfan syndromes (also rare)

CLINICAL FINDINGS

Symptoms and Signs

• Most are asymptomatic

• Substernal back or neck pain

• Pressure on the trachea, esophagus, or superior vena cava can result in

  • Dyspnea, stridor, or brassy cough

  • Dysphagia

  • Edema in the neck and arms

  • Distended neck veins

• Hoarseness due to stretching of the left recurrent laryngeal nerve

• Aortic regurgitation with aneurysms of the ascending aorta

Differential Diagnosis

• Usually asymptomatic

• Other causes of chest pain, back pain, neck pain, dyspnea, or dysphagia

DIAGNOSIS

Imaging Studies

• Chest radiograph shows calcified outline of the dilated aorta

• CT scanning with contrast enhancement is modality of choice; magnetic resonance angiography may also be used to

  • Demonstrate the anatomy and size of the aneurysm

  • Exclude lesions that can mimic aneurysms, such as neoplasms or substernal goiter

Diagnostic Procedures

• Cardiac catheterization and echocardiography may be required to describe the relationship of the coronary vessels to an aneurysm of the ascending aorta

TREATMENT

Surgery

• Indications for repair depend on

  • Location of dilation

  • Rate of growth

  • Associated symptoms

  • Overall condition of patient

• Proximal aortic arch or ascending aorta aneurysms

  • May be considered for repair when they measure 5.5 cm

  • Repair of aortic arch aneurysms should only be done by a skilled surgical team who have an acceptable record of outcomes

Therapeutic Procedures

• Descending thoracic aneurysms

  • Should be considered for repair when measuring ≥ 5.5 cm

  • Routinely treated by endovascular grafting

• Complex branched endovascular reconstructions (custom-made grafts with branches to the vessels that would be occluded by the grafts) for aneurysms involving the arch or visceral aorta does not change indication for aneurysm repair

OUTCOME

Complications

• With the exception of endovascular repair for discrete saccular aneurysms of the descending thoracic aorta, the morbidity and mortality of thoracic aneurysm repair is higher than for infra-renal abdominal aortic aneurysm repair

• Paraplegia (4–10% rate following endovascular repair of thoracic aortic aneurysms)

  • The more extensive the aneurysm, the greater the risk of paraplegia with repair

  • Prior infra-renal abdominal aortic surgery, subclavian or internal iliac artery occlusion, and hypotension increase paraplegia risk

• Open surgery for aneurysms that involve the proximal aortic arch or ascending aorta carries substantial ...