Management of 2.3cm Saccular Infrarenal Abdominal Aortic Aneurysm
Yes, close surveillance with imaging every 6 months is necessary for this saccular aneurysm, and you should strongly consider earlier intervention given the saccular morphology, even at this relatively small size.
Why Saccular Aneurysms Require Different Management
Saccular aneurysms behave differently than typical fusiform AAAs and warrant heightened concern:
- Saccular AAAs are more likely to become symptomatic and rupture at smaller diameters than fusiform aneurysms 1
- In a Dutch registry, 25% of saccular AAAs presenting acutely had diameters <5.5 cm, and 8.4% had diameters <4.5 cm, compared to only 8.1% and 0.6% respectively for fusiform AAAs 1
- The ACC/AHA guidelines recommend considering intervention for saccular AAAs based on morphology alone, with a lower threshold than fusiform aneurysms 2
- The European Society of Cardiology recommends considering intervention for saccular aneurysms ≥4.5 cm 2
Recommended Surveillance Protocol
For your 2.3cm saccular aneurysm that does not yet meet intervention thresholds:
- Perform duplex ultrasound surveillance every 6 months 1, 2
- Consider CT angiography with 3D reconstruction to better characterize the saccular morphology and establish baseline measurements 2
- If growth is ≥5 mm in 6 months or ≥10 mm per year, refer immediately for vascular surgery evaluation regardless of absolute size 2
When to Intervene
Elective repair should be strongly considered when:
- The aneurysm reaches ≥4.5 cm (given saccular morphology) 2
- Any symptoms develop (abdominal/back pain, tenderness, embolization) 1
- Rapid growth occurs (≥5 mm in 6 months or ≥10 mm per year) 2
Critical Pitfalls to Avoid
- Do not wait until 5.5 cm as you would with a fusiform AAA - this exposes the patient to unnecessary rupture risk given the higher-risk saccular morphology 2
- Do not rely on angiography alone for size assessment; ultrasound or CTA provides more accurate diameter measurements 3
- Ensure aggressive cardiovascular risk factor management, particularly blood pressure control and smoking cessation, as these accelerate aneurysm growth 1
Additional Considerations
- Assess the entire aorta at baseline, as multiple aneurysms may coexist 1
- Research data shows saccular AAAs have a mean growth rate of 2.8±2.9 mm/year, with decreased calcium burden and increased patient age predicting faster growth 4
- Approximately 30% of patients with saccular AAAs under surveillance ultimately require surgical intervention 4