Management of Multiple Intracranial and Splenic Artery Aneurysms
For multiple intracranial aneurysms, refer to a high-volume center for individualized treatment planning considering endovascular coiling as first-line for most locations (especially basilar apex) except middle cerebral artery aneurysms where microsurgical clipping is preferred; for the splenic artery aneurysm, pursue endovascular embolization if >2 cm or symptomatic, otherwise observe with serial imaging. 1
Intracranial Aneurysm Management
Critical Decision Factors
The presence of multiple aneurysms is itself a high-risk feature that warrants treatment consideration 1. Your management algorithm should prioritize:
- Size, location, and morphology of each aneurysm
- Patient age (>65 years favors observation for small lesions)
- Documented growth on serial imaging
- Family history of cerebral aneurysm or prior subarachnoid hemorrhage
Treatment Selection Algorithm
Endovascular coiling is preferred over microsurgical clipping for most unruptured intracranial aneurysms due to lower procedural morbidity, mortality, shorter hospital stays, and reduced costs, though it carries higher recurrence rates 1. The guidelines specifically note:
- Basilar apex and vertebrobasilar confluence aneurysms: Endovascular repair is advantageous
- Middle cerebral artery aneurysms: Microsurgery shows better outcomes
- Patients >60 years: Endovascular approach strongly favored since recurrence risk becomes less relevant over their lifetime 1
Critical Caveats
Treatment must occur at a high-volume center (>20 cases annually) as outcomes are significantly inferior at low-volume centers 1. This is a Class I recommendation with Level B evidence.
For small asymptomatic aneurysms in patients >65 years with medical comorbidities, observation with serial imaging is reasonable when hemorrhage risk is low based on size, location, and morphology 1.
Splenic Artery Aneurysm Management
Treatment Threshold Algorithm
Endovascular treatment is now first-line therapy for splenic artery aneurysms and should be pursued when 2, 3, 4:
- Size >2 cm (most consistent threshold across studies)
- Symptomatic (abdominal pain)
- Documented growth on serial imaging
- Women of childbearing age (though recent data shows this is often not followed in practice 5)
- Pregnancy or liver transplant recipients (high rupture risk)
- Any pseudoaneurysm (all require treatment)
Observation Criteria
For aneurysms <2 cm that are asymptomatic and calcified, observation is reasonable 6, 5. Recent natural history data shows:
- Mean growth rate of only 0.166-0.172 mm/year for aneurysms <20 mm 5
- Rupture risk is negligible for small aneurysms (only 1 rupture in 853 patients over 4 years, occurring in a 25 mm aneurysm) 5
- Calcification correlates with decreased size and likely stability 6
Endovascular Technique
The most effective approach uses coil embolization with or without covered stent placement, achieving technical success rates of 95.5% 7. For complicated anatomies (origin aneurysms, aberrant vessels), dense embolization of the sac and outflow artery with collateral embolization provides durable exclusion 7.
Mortality with endovascular treatment is 0.5% versus 4.9% with open surgery, though this difference was not statistically significant in pooled analysis 3. Endovascular repair demonstrates mean 1.5 mm regression in aneurysm size over 2 years with durable results 6.
Integrated Management Strategy
Prioritization
Address the intracranial aneurysms first as they carry higher morbidity and mortality risk from rupture compared to splenic artery aneurysms. The splenic aneurysm can be addressed in a staged fashion unless it meets high-risk criteria (>2 cm, symptomatic, or in a woman of childbearing age).
Follow-up Protocol
- Intracranial aneurysms: Early post-treatment imaging to document obliteration degree, then increased frequency for incompletely treated aneurysms to detect recurrence and de novo formation 1
- Splenic artery aneurysm: If observed, serial CT imaging at 6-12 month intervals given slow growth rates of 0.2 mm/year 6, 5
Common Pitfall
Do not attempt treatment at a low-volume center for the intracranial aneurysms—this is associated with significantly worse outcomes and warrants referral 1.