Abdominal Aortic Aneurysm

An Abdominal Aortic Aneurysm (AAA) is a localized abnormal dilation (bulging) of the abdominal aorta, typically below the renal arteries. It can be life-threatening if it ruptures, so early detection and monitoring are key.

🔹 Definition

An AAA is defined as an aortic diameter ≥3.0 cm.

• Normal abdominal aorta: ~2 cm
• Aneurysms can be classified as:
• Small: 3.0–4.9 cm
• Medium: 5.0–5.4 cm
• Large: ≥5.5 cm (higher risk of rupture)

🔸 Risk Factors

• Male sex (4–6x more common in men)
• Age > 65
• Smoking (strongest modifiable risk)
• Hypertension
• Family history of AAA
• Atherosclerosis
• Connective tissue disorders (e.g., Marfan, Ehlers-Danlos – rare but important)

🔹 Symptoms

Most AAAs are asymptomatic and found incidentally.

When present, symptoms may include:

• Pulsatile abdominal mass
• Abdominal, back, or flank pain
• Compression symptoms (e.g., early satiety, urinary symptoms)

Ruptured AAA presents with:

• Severe abdominal or back pain
• Hypotension or shock
• Pulsatile abdominal mass ⚠️ This is a surgical emergency with a high mortality rate.

🔸 Diagnosis

• Abdominal ultrasound: First-line for screening and monitoring
• CT angiography (CTA): Best for detailed anatomy and pre-surgical planning
• MRI angiography (MRA): Alternative if contrast is contraindicated

🔹 Management

Monitoring

• 3.0–3.9 cm: Ultrasound every 2–3 years
• 4.0–4.9 cm: Every 12 months
• 5.0–5.4 cm: Every 6 months or consider surgery based on symptoms/risk
• Popliteal artery [the lower extremity artery behind the knee joint] aneurysms are seen along with AAAs. Therefore, we screen for them when we detect an AAA.

Indications for Endovascular Repair or Surgery

• Diameter ≥5.5 cm in men (≥5.0 cm in women, depending on guidelines)
• Rapid growth (>0.5 cm in 6 months or >1 cm/year)
• Symptomatic aneurysms (regardless of size)
• Rupture

Endovascular or Surgical Options

• Endovascular aneurysm repair (EVAR): Minimally invasive, faster recovery, but may require follow-up for endoleaks. Most preferred form of treatment.
• Open surgical repair (OSR): Traditional, durable. Higher risk of short term complications.

🔸 Screening Guidelines

• One-time ultrasound screening:
• Men 65–75 who have ever smoked
• Consider in women with strong risk factors