Abdominal Aortic Aneurysm (AAA)

• Normally the diameter of the abdominal aorta ranges from 1.2–2.4 cm.
• The threshold for diagnosis of AAA is an abdominal aortic diameter of 3.0 cm or greater.

• More common in males and those over the age of 65.
• Associated with other vascular aneurysms, particularly popliteal artery aneurysms.

• Smoking: Single most important risk factor.
• Age
• Family history of AAA
• Hypertension
• Hypercholesterolaemia
• Atherosclerosis

• Debate on the exact cause but atherosclerosis is considered a major contributor.
• Inflammatory processes weaken the aortic wall, leading to dilatation.

• Most are asymptomatic and found incidentally on imaging or examination.
• Symptoms, if present, include:

  • Abdominal pain or back pain.
  • Pulsatile mass in the abdomen.

If ruptured:

• • Severe abdominal pain
  • Shock
  • Collapse

• Abdominal ultrasound: First-line investigation and used for screening.
• CT angiography: Provides detailed imaging, particularly if surgery is being considered.

• Small AAAs (<5.5cm in men, <5cm in women):
  • Managed conservatively with regular monitoring and ultrasound scans.

• Larger or rapidly expanding AAAs:

  • May require surgical intervention either by open repair or endovascular aneurysm repair (EVAR).

• Other management considerations:
  • Optimise blood pressure control.
  • Stop smoking.
  • Statins and aspirin if indicated.

• Rupture: Life-threatening emergency with high mortality.
• Thrombosis or embolisation from the aneurysm.

• With early detection and appropriate management, prognosis can be good.
• Ruptured AAA has a high mortality rate, with many patients dying before reaching the hospital.