Overview

Localized dilation of all three layers of the abdominal aortic wall (intima, media, and adventitia) to ≥ 3 cm

• Peak incidence: 60–70 years (rare in patients < 50 years)

• Sex: ♂ > ♀: ∼ 2:1

• Smoking (most important risk factor)

• Advanced age

• Atherosclerosis (ASCVD)

• Hypercholesterolemia and arterial hypertension

• Positive family history

• Male sex

• Trauma

• Localization

  • Infrarenal: below the renal arteries

    • Most common location [3]

    • One-third of aneurysms extend into the iliac arteries. [1]

  • Suprarenal: above the renal arteries

• Shape

  • Saccular (spherical) [4]

  • Fusiform (spindle-shaped)

• 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 → mechanical stress (e.g., high blood pressure) acts on weakened wall tissue → dilation and rupture may occur.

• 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 usually asymptomatic or have nonspecific symptoms. They are often discovered incidentally on ultrasound or CT scan. Rupture or dissection of the aneurysm is a life-threatening condition (see “Ruptured AAA”).

• Lower back pain

• Pulsatile abdominal mass at or above the level of the umbilicus

• Bruit on auscultation

• Peripheral thrombosis and distal atheroembolic phenomena (e.g., blue toe syndrome and livedo reticularis)

• Decreased ankle brachial index

Blue toe syndrome

Right foot (dorsal view)

Purplish discoloration of the toes and livedo reticularis of the back of the foot are visible.

Blue toe syndrome is a manifestation of insufficient perfusion, usually caused by cholesterol embolization of an artery (typically after an invasive vascular procedure).