What is the appropriate management for an incidental finding of a 3mm basilar artery (BA) aneurysm?

From the Guidelines

For an incidental finding of a 3mm basilar artery aneurysm, the appropriate management is observation with periodic imaging surveillance, rather than immediate intervention, due to the low risk of rupture associated with small aneurysms of this size. The patient should undergo baseline imaging with either CT angiography (CTA) or MR angiography (MRA), with follow-up imaging at 6-12 month intervals initially to monitor for growth or changes in the aneurysm's morphology 1. If the aneurysm remains stable over time, the surveillance interval may be extended.

Key Considerations

• The risk of rupture for aneurysms less than 10mm in diameter is relatively low, with a reported rupture rate of 0.05%/y in patients with aneurysms < 10 mm in diameter 1.
• Aneurysm location also predicts future rupture, with posterior communicating, vertebrobasilar/posterior cerebral, and basilar tip UIAs being more likely to rupture 1.
• Blood pressure control is essential, with a target of less than 140/90 mmHg using appropriate antihypertensive medications if needed.
• The patient should also be counseled to avoid smoking, excessive alcohol consumption, stimulant use, and activities that cause sudden increases in blood pressure.

Management Approach

• Referral to a neurosurgeon or neurointerventional specialist for consultation and further evaluation is recommended.
• Observation with periodic imaging surveillance is typically recommended for small aneurysms (less than 7mm) due to the low risk of rupture.
• The patient should be fully informed about the risks and benefits of both endovascular and microsurgical treatment as alternatives to secure the UIAs and prevent bleeding 1.
• Treatment at higher-volume centers is recommended due to superior outcomes compared to low-volume centers 1.

From the Research

Management of Incidental Basilar Artery Aneurysm

• The management of an incidental finding of a 3mm basilar artery (BA) aneurysm is complex and requires careful consideration of various factors, including the size and location of the aneurysm, as well as the patient's overall health status 2, 3.
• Endovascular treatment has become a popular option for managing BA aneurysms, with studies showing good clinical and angiographic outcomes 2, 3.
• The choice of treatment strategy depends on the morphology of the aneurysm, including its size, shape, and relationship to the surrounding blood vessels 2.
• A systematic review of 68 studies found that most patients with BA fenestration aneurysms underwent endovascular treatment, with a complication rate of 8.3% and a retreatment rate of 7.3% 3.
• Another study found that endovascular treatment was safe and efficient for BA fenestration aneurysms, with a complication rate of 11.1% 2.

Considerations for Treatment

• The size of the aneurysm is an important factor in determining the treatment strategy, with smaller aneurysms potentially being managed more conservatively 4.
• The location of the aneurysm, including its relationship to the fenestration, is also crucial in determining the treatment approach 2, 3.
• The patient's overall health status, including the presence of any comorbidities, should also be taken into account when determining the treatment strategy 3.
• Imaging studies, such as CT angiography and MRI, can provide valuable information for pre-treatment planning and can help identify any congenital or acquired anomalies of the basilar artery 5.

Risks and Complications

• Delayed rupture of a previously coiled aneurysm is a rare but potentially life-threatening complication, highlighting the need for close follow-up and monitoring 4.
• The risk of complications, including stroke and death, is higher for patients undergoing microsurgical treatment compared to endovascular treatment 3.
• The risk of retreatment is also higher for patients undergoing endovascular treatment, highlighting the need for careful follow-up and monitoring 3.