What is the treatment for a saccular aneurysm in the abdominal aorta?

Treatment of Saccular Abdominal Aortic Aneurysm

Saccular abdominal aortic aneurysms require elective repair at a lower diameter threshold than fusiform aneurysms—specifically at 45 mm or greater—due to their significantly higher rupture risk at smaller sizes. 1, 2

Immediate Risk Assessment and Intervention Threshold

Saccular AAAs are fundamentally different from fusiform aneurysms and demand more aggressive management:

• Elective repair should be performed when saccular AAA diameter reaches ≥45 mm, as 25.2% of ruptured saccular AAAs present at diameters <55 mm and 8.4% rupture at <45 mm, compared to only 8.1% and 0.6% respectively for fusiform aneurysms 2
• Any symptomatic saccular AAA requires immediate intervention regardless of diameter 1
• Rapid growth ≥10 mm per year or ≥5 mm in 6 months triggers intervention even below the 45 mm threshold 1

The saccular morphology itself represents a high-risk feature due to focal wall stress, intraluminal thrombus formation, and asymmetric hemodynamic forces 3, 4

Pre-Intervention Imaging Requirements

Before proceeding with repair, obtain comprehensive anatomic assessment:

• Contrast-enhanced CT angiography is mandatory to measure true aneurysm diameter, evaluate the complete aorto-iliac system, assess thrombus burden, and determine feasibility of endovascular versus open repair 1, 5
• Duplex ultrasound of the femoro-popliteal segment should be performed as coexistent peripheral aneurysms are common 1

Choice of Repair Technique

Endovascular aneurysm repair (EVAR) is the preferred approach for patients with suitable anatomy and life expectancy >2 years, reducing perioperative mortality to <1% 1

EVAR is appropriate when:

• Adequate proximal neck (>10-15 mm length, <30 mm diameter) exists for graft seal 5
• Patient can comply with mandatory long-term surveillance imaging 1
• Anatomy is suitable for endograft deployment 1

Open surgical repair is indicated when:

• Patient cannot comply with post-EVAR surveillance requirements 1
• Anatomy is unsuitable for EVAR (inadequate proximal neck, severe iliac tortuosity) 1, 5
• Young patients with long life expectancy where durability is paramount 1

Medical Management Concurrent with Surgical Planning

While arranging surgical intervention, implement aggressive risk factor modification:

• Immediate smoking cessation is critical, as smoking is the strongest modifiable risk factor for AAA expansion and rupture 5
• Blood pressure control with target <120 mmHg systolic to reduce wall stress 1
• Avoid fluoroquinolone antibiotics unless no alternative exists, as they increase rupture risk 1
• Statin therapy for cardiovascular risk reduction 5

Post-Repair Surveillance

After EVAR, structured follow-up is essential:

• 30-day imaging with contrast-enhanced CT plus duplex ultrasound to assess intervention success 1
• Follow-up schedule at 1 month, 12 months, then yearly until fifth post-operative year 1
• Immediate re-intervention for Type I or Type III endoleaks to prevent rupture 1

Management of Ruptured Saccular AAA

If rupture occurs before planned repair:

• Permissive hypotension strategy (systolic BP <120 mmHg) to decrease bleeding rate until definitive treatment 1
• Intravenous beta blockers as first-line agents, targeting heart rate 60-80 bpm 1
• Emergency EVAR is preferred over open repair if anatomy is suitable, to reduce perioperative morbidity and mortality 1
• For hemodynamically stable patients, obtain CT imaging to evaluate EVAR suitability before proceeding 1

Critical Pitfall to Avoid

Do not apply the standard 55 mm threshold used for fusiform AAAs to saccular aneurysms—this approach results in preventable ruptures, as demonstrated by the 25% of saccular AAAs that rupture below 55 mm 2. The mortality from ruptured AAA approaches 90% 3, making early elective repair at 45 mm the evidence-based standard for saccular morphology.