Splenic Artery Aneurysm Intervention Threshold
Splenic artery aneurysms ≥2 cm in diameter require intervention, with endovascular treatment as the preferred first-line approach. 1, 2, 3
Size-Based Intervention Criteria
- Aneurysms ≥2 cm mandate treatment due to significantly elevated rupture risk, with mortality rates of 10-25% in non-pregnant patients 1, 2
- Aneurysms showing growth of >0.5 cm per year require intervention even if they have not yet reached 2 cm 2, 3
- The 2 cm threshold is based on rupture risk stratification, as larger aneurysms demonstrate substantially higher rates of complications 3, 4, 5
Absolute Indications Regardless of Size
High-Risk Populations Requiring Immediate Treatment
- All splenic artery aneurysms in pregnant women or women of childbearing age warrant treatment regardless of size, as rupture during pregnancy carries catastrophic maternal mortality of 21.9-70% and fetal mortality of 15.6-90% 1
- Critically, up to 50% of aneurysms that rupture during pregnancy are <2 cm in diameter, making size-based criteria unreliable in this population 1
- Rupture risk peaks in the third trimester when splenic blood flow from hyperdynamic circulation is maximal 1
Other Absolute Indications
- All symptomatic aneurysms require intervention regardless of size 1, 3, 6
- Patients awaiting liver transplantation or with portal hypertension should undergo treatment due to increased rupture risk 1, 3
- All false (pseudoaneurysms) require treatment as they have greater rupture potential and grow faster than true aneurysms 2, 3
Treatment Approach Algorithm
First-Line: Endovascular Therapy
- Transcatheter embolization is the preferred initial treatment for stable patients with aneurysms meeting intervention criteria 1, 2, 3
- Technical success rates range from 67-100%, with the isolation technique (coils placed proximal and distal to the aneurysm) providing excellent long-term results 1, 5
- Endovascular treatment offers shorter hospital stays (median 8 days vs 16 days for surgery), lower morbidity, and comparable long-term outcomes to open surgery 5
Second-Line: Surgical Treatment
- Open surgical repair or laparoscopic splenectomy is reserved for: 4, 6
- Failed endovascular attempts
- Ruptured aneurysms with hemodynamic instability
- Aneurysms near the splenic hilum where embolization is technically unfavorable
- Symptomatic aneurysms where endovascular success is unlikely
Surveillance for Aneurysms <2 cm
- Conservative management with regular imaging is appropriate for asymptomatic aneurysms <2 cm in low-risk patients (non-pregnant, no portal hypertension) 3, 4
- These patients require serial imaging to monitor for growth, with intervention indicated if the aneurysm reaches 2 cm or grows >0.5 cm per year 2, 3
Critical Pitfalls to Avoid
- Never delay treatment in women of childbearing age based on size criteria alone, as smaller aneurysms frequently rupture during pregnancy 1
- Do not rely on symptoms to guide intervention timing, as approximately 80% of splenic artery aneurysms are asymptomatic until rupture 1
- Prophylactic screening should be considered for patients with multiple risk factors, particularly pregnancy in liver transplant recipients 3