What is the recommended surveillance for a 1 cm splenic artery aneurysm?

Surveillance of 1 cm Splenic Artery Aneurysm

For a 1 cm splenic artery aneurysm, conservative management with imaging surveillance is recommended, as this size is well below the 2 cm threshold for intervention. 1

Treatment Threshold and Risk Stratification

The ACC/AHA guidelines establish clear size-based criteria for visceral artery aneurysms:

• Intervention is indicated for splenic artery aneurysms ≥2.0 cm in women of childbearing age (not currently pregnant) and patients undergoing liver transplantation 1
• Intervention is probably indicated for aneurysms ≥2.0 cm in women beyond childbearing age and in men 1
• Aneurysms <2.0 cm can be managed conservatively with surveillance imaging 1, 2

Your 1 cm aneurysm is half the size threshold for intervention, placing it in the low-risk category for rupture.

Recommended Surveillance Protocol

Perform imaging surveillance every 2-3 years for stable aneurysms <2 cm in diameter. 2

Imaging Modality Selection

• Ultrasound or CT are both acceptable modalities for surveillance 1, 2
• Doppler ultrasound is non-invasive and avoids radiation exposure 2
• CT provides superior anatomic detail if ultrasound is inadequate 1

Surveillance Endpoints - Intervene If:

• Aneurysm grows to ≥2.0 cm 1, 3
• Growth rate exceeds 0.5 cm/year 4
• Patient becomes symptomatic (upper abdominal pain) 1, 3
• Patient becomes pregnant or plans pregnancy 1, 3
• Patient requires liver transplantation 1

Special Considerations and Pitfalls

High-Risk Populations Requiring Closer Monitoring

Even at 1 cm, certain patient populations warrant more aggressive surveillance or earlier intervention:

• Women of childbearing age: Maternal mortality from rupture during pregnancy approaches 70%, with fetal mortality >90% 1
• Patients with portal hypertension: Increased rupture risk, though specific data for small aneurysms is limited 1, 2
• Patients awaiting liver transplantation: Should undergo prophylactic treatment even for smaller aneurysms 1

False vs. True Aneurysms

All false (pseudo) aneurysms should be treated regardless of size due to their higher rupture potential and faster growth rate. 3, 4 Ensure imaging clearly distinguishes between true and false aneurysms, as this fundamentally changes management.

Evidence Quality Note

The guidelines for visceral aneurysms are based primarily on Level B evidence (observational studies and case series), as randomized trials are not feasible for these rare lesions. 1 The 2 cm threshold represents consensus based on natural history studies showing acceptable rupture rates below this size in non-high-risk patients. 1, 2

Practical Algorithm

1. Confirm diagnosis with quality cross-sectional imaging (CT or ultrasound) 1, 2
2. Assess patient risk factors: pregnancy status/plans, liver disease, portal hypertension 1
3. If low-risk patient with 1 cm aneurysm: Surveillance imaging every 2-3 years 2
4. If high-risk patient: Consider annual surveillance or prophylactic treatment at lower threshold 1, 3
5. Intervene if: Size ≥2 cm, growth ≥0.5 cm/year, symptoms develop, or high-risk status changes 1, 3, 4