What is the best management approach for a 72-year-old male with hypertension and a history of heavy smoking who has a 4.5cm abdominal aortic aneurysm?

Management of 4.5cm Abdominal Aortic Aneurysm

This patient requires periodic surveillance with ultrasound imaging every 6 months, not urgent surgery or reassurance alone. 1, 2

Rationale for Surveillance Over Surgery

The 4.5cm diameter places this AAA in the intermediate-size category (4.0-5.4cm), which falls below the threshold for elective repair:

• Elective repair is reserved for AAAs ≥5.5cm in diameter 1, 2
• For intermediate-sized AAAs (4.0-5.4cm), periodic surveillance offers comparable mortality benefit to routine elective surgery with the significant advantage of fewer operations 1
• The 1-year rupture risk for AAAs of 5.5-5.9cm is only 9%, and this patient's aneurysm is smaller 1

Surveillance Protocol

Follow-up imaging should occur every 6 months for aneurysms measuring 4.5-5.4cm in diameter 1, 2:

• Ultrasound is the appropriate modality for surveillance 1, 2
• If the aneurysm grows to ≥5.5cm or expands rapidly (>1.0cm/year), surgical intervention becomes indicated 1
• CT angiography may be helpful before continued surveillance to better describe aneurysm morphology, as saccular morphology can increase rupture risk even below the 5.5cm threshold 1

Risk Factor Management is Critical

This patient has multiple high-risk features that require aggressive medical management:

• Heavy smoking history - the strongest modifiable risk factor for AAA expansion and rupture 1
• Hypertension - associated with increased AAA risk and expansion 1, 3
• Age 72 years and male sex - both independent risk factors 1, 4

Immediate interventions must include:

• Smoking cessation counseling and pharmacotherapy 1, 5
• Optimal blood pressure control 1, 5
• Statin therapy for cardiovascular risk reduction 1
• Consideration of beta-blocker therapy 5

Why Other Options Are Incorrect

Reassurance (Option A) is inappropriate because a 4.5cm AAA requires active surveillance and risk factor modification, not passive observation 1, 2

Urgent surgery (Option B) is not indicated as the aneurysm has not reached the 5.5cm threshold where rupture risk justifies the 4-5% operative mortality and significant morbidity of open repair 1

Aneurysm endarterectomy (Option D) is not a treatment for AAA - this confuses AAA management with carotid artery disease treatment 1

Common Pitfalls to Avoid

• Do not delay surveillance imaging beyond 6 months for this size aneurysm, as expansion rates can be unpredictable 1, 2
• Do not ignore cardiovascular risk factor modification - this patient's smoking and hypertension significantly increase both AAA expansion risk and perioperative mortality if surgery becomes necessary 1
• Ensure quality-assured ultrasonography (95% sensitivity, near 100% specificity) rather than relying on physical examination alone 1

Answer: C. Follow up with ultrasound 1, 2