What is the management approach for congenital hypoplasia of the right vertebral artery?

Management of Congenital Hypoplasia of the Right Vertebral Artery

Medical management following carotid artery disease guidelines is the recommended approach for congenital hypoplasia of the right vertebral artery, as there are no randomized trials specifically evaluating treatment for vertebral artery anomalies.

Clinical Significance and Presentation

• Congenital vertebral artery hypoplasia occurs in approximately 2-6% of the population and may serve as an independent risk factor for posterior circulation ischemia 1, 2
• Patients with vertebral artery hypoplasia have a higher statistical incidence of brainstem/cerebellar infarction and may show preponderance for ipsilateral posterior circulation infarction 1
• Common symptoms associated with vertebral artery disease include dizziness, vertigo, diplopia, perioral numbness, blurred vision, tinnitus, ataxia, bilateral sensory deficits, and syncope 3
• Symptoms may be provoked by head turning, especially when lesions occur at the midportion of the vertebral arteries 4

Diagnostic Approach

• Initial evaluation should include thorough clinical assessment followed by non-invasive imaging 3
• CTA and contrast-enhanced MRA are preferred imaging modalities with higher sensitivity (94%) and specificity (95%) compared to ultrasonography (sensitivity 70%) 3
• Neither MRA nor CTA reliably delineates the origins of the vertebral arteries; catheter-based angiography may be required for definitive diagnosis, particularly before considering any revascularization 3
• Assessment of collateral circulation is essential, as most patients with congenital vertebral anomalies develop sufficient cerebral circulation through the circle of Willis, intercavernous anastomosis, and persistent embryologic arteries 5

Medical Management

• Despite limited evidence specific to vertebral artery hypoplasia, medical management should follow guidelines for carotid artery disease 3
• For symptomatic patients with evidence of ischemia:
  • Antiplatelet therapy is recommended as first-line treatment 3
  • Combination therapy with aspirin plus dipyridamole has shown benefit in reducing recurrent vertebrobasilar territory strokes compared to placebo (5.7% vs 10.8%) 3
  • Ticlopidine has demonstrated superiority to aspirin for secondary prevention of ischemic events in patients with symptomatic posterior circulation disease 3
• For patients with acute ischemic syndromes involving the vertebral artery territory and angiographic evidence of thrombus, anticoagulation is generally recommended for at least 3 months 3
• The WASID trial found aspirin and warfarin to be equally efficacious after initial non-cardioembolic ischemic stroke 3

Revascularization Considerations

• Surgical interventions are rarely performed for vertebral artery anomalies, and no randomized trials have addressed operative procedures for posterior cerebral circulation disease 3
• For symptomatic patients who fail medical therapy, revascularization might be considered, but evidence is limited 3
• Endovascular management has not been proven superior to best medical management in randomized trials 3
• In a review of 300 interventions for proximal vertebral artery stenosis, risks included death (0.3%), periprocedural neurological complications (5.5%), and posterior stroke (0.7%) at mean follow-up of 14.2 months 3
• Restenosis occurred in 26% of cases after endovascular intervention but was not consistently correlated with recurrent symptoms 3

Special Considerations and Pitfalls

• Vertebral artery hypoplasia often coexists with other vascular anomalies, including hypoplastic basilar artery and variations in the circle of Willis, which may compound stroke risk 6
• Asymptomatic patients with incidentally discovered vertebral artery hypoplasia generally do not require specific treatment but should be monitored for development of symptoms 2, 5
• Patients with bilateral vertebral hypoplasia or hypoplasia with contralateral vertebral occlusion are at particularly high risk for posterior circulation events and warrant more aggressive medical management 4, 6
• Avoid attributing non-specific symptoms (dizziness, vertigo) solely to vertebral hypoplasia without excluding other common causes such as cardiac arrhythmias, orthostatic hypotension, and vestibular disorders 3