What is the management approach for brain aneurysms based on size?

From the Guidelines

The management approach for brain aneurysms is primarily determined by size, with different strategies for different size categories, prioritizing morbidity, mortality, and quality of life as the outcome. For small aneurysms less than 7mm, observation with regular imaging follow-up is often recommended, particularly for asymptomatic aneurysms in low-risk locations, as the annual rupture risk is approximately 0.05% per year for aneurysms <10 mm in diameter 1. These patients should undergo periodic imaging with either MRA or CTA every 6-12 months initially, then extending to every 1-2 years if stable.

• Key factors influencing the management approach include aneurysm size, location, patient age, and comorbidities.
• For medium-sized aneurysms (7-12mm), treatment is generally recommended due to higher rupture risk, especially in posterior circulation or communicating artery locations, with an annual rupture risk of approximately 1% per year for larger aneurysms 1.
• Large (13-24mm) and giant (>25mm) aneurysms almost always warrant intervention regardless of symptoms due to their significantly higher rupture rates of approximately 3-8% per year.
• Treatment options include surgical clipping, which involves placing a metal clip across the aneurysm neck to exclude it from circulation, or endovascular techniques such as coiling, flow diversion, or stent-assisted coiling, with coiling now recommended over clipping to improve 1-year patient outcomes for ruptured aneurysms 1.
• The choice between these approaches depends on aneurysm morphology, location, patient age, and comorbidities, and should be a multidisciplinary decision based on characteristics of the patient and the aneurysm 1.
• Patients with untreated aneurysms should maintain blood pressure control (typically aiming for <140/90 mmHg), avoid smoking, limit alcohol consumption, and avoid activities that cause sudden increases in blood pressure, to reduce the risk of rupture and improve overall quality of life.

From the Research

Brain Aneurysm Management Based on Size

The management approach for brain aneurysms varies based on their size, among other factors. Here are some key points to consider:

• Small aneurysms (< 7 mm): These aneurysms are often observed to detect growth or shape change, with repeated computed tomography angiography (CTA) or magnetic resonance angiography (MRA) studies 2.
• Aneurysm growth detection: Dome volume assessment is superior to single dimension assessment in aneurysm growth detection, and confidence intervals assessment helps to avoid overestimation of growth 2.
• Diagnostic accuracy of CT angiography: CT angiography has high accuracy for detection of small cerebral aneurysms, including those smaller than 3 mm, with digital subtraction angiography (DSA) as the reference standard 3.
• Giant aneurysms (> 3.5 cm): These aneurysms can produce dementia due to direct brain compression, and optic apparatus compression can occur with smaller aneurysms (2.7-3.2 cm) when they point inferiorly 4.
• Treatment approaches: The choice of treatment, endovascular or surgical, should be based on the angio-architectural aspects of the aneurysm, and aneurysm neck clipping is possible in some cases, while special techniques may be required in others 5, 4.

Key Considerations

• Aneurysm size and location: These factors influence the treatment decision, with posterior circulation aneurysms growing faster than anterior ones 2.
• Imaging modalities: CTA and MRA are useful for detecting and monitoring aneurysm growth, while DSA is the reference standard for diagnosis 2, 3.
• Treatment outcomes: The outcome of treatment depends on various factors, including aneurysm size, location, and treatment approach, with proximal ACA occlusion being an effective treatment alternative in some cases 4.