What is the treatment for an aneurysm?

Treatment of Intracranial Aneurysms

For ruptured intracranial aneurysms, immediate treatment within 24-72 hours with either endovascular coiling or surgical clipping is essential to prevent catastrophic rebleeding, which carries a 20% risk in the first 2 weeks and substantially increases mortality with each subsequent rupture. 1

Ruptured Aneurysm Management

Timing of Intervention

• Early treatment (within 24-72 hours) is strongly recommended to reduce the approximately 20% rebleeding risk in the first 2 weeks after subarachnoid hemorrhage (SAH). 1
• Each additional rupture dramatically increases mortality and morbidity, making urgent intervention critical. 1
• Subarachnoid hemorrhage from ruptured aneurysms carries 32-67% case fatality and 10-20% long-term dependence in survivors. 1

Treatment Modality Selection for Ruptured Aneurysms

• For aneurysms amenable to both techniques, endovascular coiling is beneficial and should be considered first-line. 1
• Individual aneurysm characteristics (location, size, neck width) and patient factors should guide the final decision between coiling and clipping. 1
• Treatment should be performed at high-volume centers (>20 cases annually), as low-volume centers demonstrate inferior outcomes. 1

Unruptured Aneurysm Management

Size-Based Treatment Algorithm

• Aneurysms ≥5 mm in patients younger than 60 years should be offered treatment, as the cumulative lifetime rupture risk becomes significant over their remaining lifespan. 2
• Aneurysms <5 mm should generally be managed conservatively with surveillance, as annual rupture rates are extremely low and surgical risks typically outweigh benefits. 2
• The 5 mm threshold accounts for measurement error (±2 mm with angiography) and ensures appropriate treatment of at-risk patients. 2

Critical Location-Specific Considerations

• Anterior communicating artery (AComA), posterior communicating artery (PComA), and basilar apex aneurysms warrant more aggressive treatment even at smaller sizes due to higher rupture risk. 2, 3
• These high-risk locations should be treated even in older healthy individuals due to low associated treatment morbidity. 2
• Middle cerebral artery aneurysms generally favor microsurgical clipping, while basilar apex and vertebrobasilar confluence aneurysms favor endovascular repair. 1

Age-Stratified Approach

• Treat all aneurysms ≥5 mm in patients <60 years unless significant contraindications exist, as cumulative lifetime rupture risk is substantial. 2
• In patients >60 years, endovascular coiling demonstrates greater benefit than surgery for most lesions, as recurrence risk becomes less concerning over shorter life expectancy. 1
• Surgical morbidity and mortality are lowest in patients <60 years (5-6% at 1 year). 2

Treatment Modality Selection for Unruptured Aneurysms

Microsurgical Clipping:

• First choice for young patients with small anterior circulation aneurysms, providing durability with 0% recurrence rate versus 23-34% recanalization with coiling. 2
• Generally associated with higher perioperative morbidity (10.1-12.6% at 1 year) but higher rates of complete aneurysm obliteration and lower recurrence. 1, 2
• Combined morbidity/mortality ranges from 4-15.3% with mortality 0-7%. 3

Endovascular Coiling:

• Appropriate for elderly patients, medically ill patients, posterior circulation aneurysms, and anatomically unfavorable surgical cases. 2, 4
• Lower perioperative morbidity (7.1-9.8% at 1 year) but higher recurrence rates requiring long-term surveillance. 1, 2
• Complete occlusion achieved in only 54% of aneurysms after initial coil embolization. 4
• Mortality rate of 1.4% and moderate/severe disability rate of 1.4% for unruptured aneurysms. 4

Mandatory Treatment Indications

• All symptomatic unruptured aneurysms should be treated with rare exceptions, including those causing compressive symptoms or serving as embolic sources. 1, 2
• Aneurysms discovered after SAH from a different lesion require treatment. 1
• Documented aneurysm growth on serial imaging mandates intervention. 1
• Family history of intracranial aneurysms or prior SAH increases treatment indication. 1

Conservative Management Criteria

• Do not proceed when treatment risks approach 25% due to extensive comorbidity, advanced age, or unfavorable anatomy. 2
• Very short or low-quality life expectancy may justify conservative management even for growing or symptomatic lesions. 1

Post-Treatment Surveillance

Immediate Post-Treatment Assessment

• Digital subtraction angiography (DSA) is typically used immediately after treatment to confirm aneurysm exclusion and assess need for repeat treatment. 1
• Early documentation of obliteration degree is necessary to guide follow-up frequency. 1

Long-Term Follow-Up

• Routine delayed follow-up imaging uses noninvasive CTA or MRA rather than DSA. 1
• Incompletely obliterated aneurysms require more frequent surveillance for recurrence and de novo aneurysm formation. 1
• Small aneurysms with small necks (<4 mm) have only 1.1% recurrence if completely coiled, versus 21% if incompletely coiled. 4
• Wrapped, coated, or incompletely treated aneurysms have increased rehemorrhage risk and require long-term angiographic follow-up. 1

Critical Pitfalls to Avoid

• Do not use 7 mm as an absolute cutoff - measurement error of ±2 mm means high-risk aneurysms would be undertreated. 2
• Do not ignore location - AComA, PComA, and basilar apex aneurysms rupture at smaller sizes than other locations. 2, 3
• Do not delay treatment in symptomatic aneurysms regardless of size. 2
• Do not treat at low-volume centers (<20 cases annually) - refer to high-volume centers for superior outcomes. 1
• Do not assume complete protection after coiling - 23-34% recanalization rate requires ongoing surveillance. 2

Screening Considerations

• Screening with MRA or CTA should target high-risk populations: patients with autosomal dominant polycystic kidney disease (especially with family history of intracranial aneurysms) and individuals with strong family history of aneurysms or SAH. 1
• Cost-effectiveness and clinical utility of screening programs have not been prospectively evaluated. 1