Indications for Treatment of Splenic Artery Aneurysm
Splenic artery aneurysms should be treated when they are ≥2 cm in diameter, symptomatic, in women of childbearing age or during pregnancy, enlarging (>0.5 cm/year), or in patients awaiting liver transplantation. 1
Size-Based Treatment Thresholds
Aneurysms ≥2 cm require intervention due to significantly increased rupture risk, with mortality rates of 10-25% in non-pregnant patients and catastrophically higher rates (up to 70% maternal and >90% fetal mortality) during pregnancy. 1, 2
Aneurysms <2 cm may be observed with periodic imaging surveillance, though this recommendation carries important caveats (see below). 3, 4
Growth of >0.5 cm per year is an indication for treatment, even if the aneurysm has not yet reached 2 cm. 5
High-Risk Patient Populations Requiring Treatment
Pregnancy and Women of Childbearing Age
All splenic artery aneurysms in pregnant women or women of childbearing age warrant treatment regardless of size, as rupture during pregnancy carries maternal mortality of 21.9-70% and fetal mortality of 15.6-90%. 1, 2
Critically, up to 50% of aneurysms that rupture during pregnancy are <2 cm in diameter, making size-based criteria unreliable in this population. 1
The risk is highest in the third trimester when splenic blood flow from hyperdynamic circulation is maximal. 1
Prophylactic intervention pre-conception is appropriate for known aneurysms >2-3 cm or those with prior rupture history. 1
Liver Transplant Candidates
Patients awaiting liver transplantation should undergo treatment of splenic artery aneurysms due to increased rupture risk in the setting of portal hypertension. 4
Portal hypertension itself increases the risk of splenic artery aneurysm formation and rupture. 1
Symptom-Based Indications
Any symptomatic splenic artery aneurysm requires treatment, including those presenting with chronic upper abdominal pain or acute symptoms. 4, 6, 7
Approximately 20% of patients present with symptoms (chronic pain or acute rupture) rather than incidental discovery. 1, 2
Pseudoaneurysms
- All false aneurysms (pseudoaneurysms) should be treated regardless of size because they have greater rupture potential and grow faster than true aneurysms. 4, 5
Important Caveats and Pitfalls
The 2 cm Rule Has Limitations
While the 2 cm threshold is widely cited, clinicians must recognize that 50% of pregnancy-related ruptures occur with aneurysms <2 cm. 1 This makes aggressive treatment of smaller aneurysms justified in women of reproductive age.
Calcification Does Not Protect
Calcified aneurysms can still rupture, so the presence of calcification should not be used as reassurance to defer treatment. 6
Conservative Management Criteria
For aneurysms <2 cm in low-risk patients (men, post-menopausal women without portal hypertension), observation with serial imaging is acceptable. 3, 4, 6 However, these patients require regular imaging surveillance to detect growth.
Treatment Approach
Endovascular therapy (coil embolization or stent grafting) is the first-line treatment with technical success rates of 67-100%. 3, 2, 4, 5
Open surgical treatment (aneurysmectomy, arterial ligation, or splenectomy) is reserved for failed endovascular attempts, ruptured aneurysms, or hemodynamically unstable patients. 8, 7
Trans-catheter embolization is the mainstay for acute rupture, with surgical ligation and splenectomy reserved for failed endovascular therapy. 1