What is the best treatment for a 6 mm x 4 mm left vertebral V2 aneurysm?

Management of Left Vertebral V2 Aneurysm (6 mm × 4 mm)

For a 6 mm × 4 mm left vertebral V2 aneurysm, endovascular treatment with flow diversion is recommended as the optimal treatment approach due to its lower complication and retreatment rates compared to stent-assisted coiling.

Risk Assessment for Vertebral Artery Aneurysms

The management decision for this aneurysm requires careful consideration of several factors:

• Size: At 6 mm × 4 mm, this aneurysm falls into the small-to-moderate size category. Aneurysms <7 mm in the anterior circulation have a very low rupture risk, but vertebral artery aneurysms are in the posterior circulation, which carries higher risk 1.

• Location: Vertebral artery aneurysms, particularly those in the posterior circulation, have a higher rupture risk compared to anterior circulation aneurysms 2, 1.

• V2 Segment: The V2 segment of the vertebral artery is extracranial, running through the transverse foramina of the cervical vertebrae, which affects treatment considerations.

Treatment Options

1. Flow Diversion

Flow diversion has emerged as a preferred treatment for vertebral artery dissecting aneurysms:

• Recent evidence shows that flow diversion devices (FDDs) are associated with lower retreatment and complication rates compared to stent-assisted coiling 3.
• In a 20-year institutional experience study, FDDs demonstrated significantly lower procedural complications and retreatment rates compared to stent-assisted coil embolization 3.
• Flow diverters have shown excellent results with complete aneurysm occlusion in most cases and improvement in neurological outcomes 4.

2. Coil Embolization

• Traditional coiling techniques have limitations for vertebral artery aneurysms:
  • Complete occlusion is less frequently achievable in aneurysms with wide necks 2.
  • High recurrence rates are observed, with incomplete coiling occurring in 25.5-59% of small aneurysms depending on neck size 2.
  • Stent-assisted coiling has shown higher complication and retreatment rates compared to flow diversion 3.

3. Surgical Options

• Surgical approaches for vertebral artery aneurysms are technically challenging:
  • Posterior circulation aneurysms are more difficult to treat with surgery 2.
  • Surgical approaches may require complex revascularization procedures with potential lower cranial nerve injuries 5.

Treatment Algorithm

1. First-line treatment: Flow diversion for this 6 mm × 4 mm vertebral V2 aneurysm

   • Provides better long-term angiographic outcomes
   • Lower retreatment rates compared to stent-assisted coiling
   • Lower procedural complication rates

2. Alternative if flow diversion is contraindicated:

   • Stent-assisted coiling, recognizing the higher retreatment and complication rates
   • Parent vessel occlusion if adequate collateral circulation is confirmed through balloon test occlusion

Post-Treatment Management

• Regular imaging follow-up to assess aneurysm occlusion (typically at 6 months initially) 1
• Dual antiplatelet therapy management is crucial following flow diverter placement
• Blood pressure control targeting systolic BP <140 mmHg to reduce risk of complications 1

Important Considerations and Pitfalls

• Antiplatelet therapy: Careful management of antiplatelet medications is essential with flow diverters to prevent thromboembolic complications 4.

• Anatomical considerations: Assessment of the contralateral vertebral artery and posterior circulation is critical before treatment to ensure adequate collateral flow.

• Follow-up protocol: Regular angiographic follow-up is necessary to detect any recurrence or incomplete occlusion, as posterior circulation aneurysms have higher recurrence rates 2.

• Neck size assessment: The ratio of neck diameter to largest aneurysm dimension should be evaluated, as ratios <0.5 are associated with better outcomes for endovascular treatment 2.

Flow diversion technology has significantly improved outcomes for vertebral artery aneurysms and represents the most effective treatment option for this specific case based on the most recent evidence.