Overview

• Dilatation of all three layers of the aortic wall (intima, media, and adventitia) to > 150% of the normal diameter (a true aneurysm) [1]

  • Ascending aorta: approx. > 5.0 cm

  • Descending aorta: approx. > 4.0 cm

• Less common than abdominal aortic aneurysm (AAA) [2]

• Peak incidence: 60–65 years [3]

• Sex: ♂ > ♀ (∼ 3:1)

• Risk factors

  • Arterial hypertension

  • Smoking

  • Advanced age

  • Trauma

  • Tertiary syphilis (due to obliterative endarteritis of the vasa vasorum) [4]

  • Connective tissue diseases (e.g., Marfan syndrome, Ehlers-Danlos syndrome)

  • Bicuspid aortic valve [5]

  • Positive family history

  • Rare: vasculitis/infectious diseases with aortic involvement (e.g., Takayasu arteritis)

• Ascending aorta (most common location) [6]

• Descending aorta (thoracoabdominal)

• Aortic arch

  
  

  
  

• Ascending thoracic aortic aneurysm: most often due to cystic medial necrosis

• Descending thoracic aortic aneurysm: typically a result of atherosclerosis

• Inflammation and proteolytic degeneration of connective tissue proteins (e.g., collagen and elastin) and/or smooth muscle cells in high-risk patients → loss of structural integrity of the aortic wall → widening of the vessel

• The aneurysmatic dilatation of the vessel wall may cause disruption of the laminar blood flow and turbulence.

• Possible formation of thrombi in the aneurysm → peripheral thromboembolism

Aortic aneurysms are mostly asymptomatic or have nonspecific symptoms. They are often discovered incidentally on imaging.

• Chest pressure

• Thoracic back pain

• Features of mediastinal compression/obstruction, such as:

  • Difficulty swallowing (esophagus)

  • Upper venous congestion (superior vena cava syndrome)

  • Hoarseness (recurrent laryngeal nerve)

  • Cough, wheeze, stridor (trachea)

  • Horner syndrome (sympathetic trunk)