What management is needed for an adult patient with a left subtotal occlusion of the left vertebral artery noted on a Computed Tomography Angiogram (CTA) head/neck?

Management of Left Subtotal Vertebral Artery Occlusion

For a patient with left subtotal vertebral artery occlusion found on CTA head/neck, you should initiate antiplatelet therapy immediately and obtain additional imaging to assess the contralateral vertebral artery and posterior circulation—revascularization is reserved only for patients who fail medical therapy with recurrent posterior circulation symptoms. 1, 2

Immediate Diagnostic Steps Required

You must obtain MRA or CTA imaging of the complete vertebrobasilar system to evaluate:

• The contralateral (right) vertebral artery patency and caliber 3, 1
• The basilar artery for propagated thrombus or stenosis 2, 4
• The posterior communicating arteries and circle of Willis completeness 3

This is critical because if both vertebral arteries are compromised or the patient has bilateral carotid occlusions with incomplete circle of Willis, the risk profile changes dramatically and more aggressive monitoring is warranted. 3

Do not rely on ultrasound alone—it has only 70% sensitivity for vertebral artery disease compared to 94% for MRA/CTA. 1, 5

Determine If This Is Acute or Chronic

If Acute Presentation (within 24 hours with new symptoms):

• NIHSS ≥6 with PC-ASPECTS ≥6 in patients age 18-89 years warrants mechanical thrombectomy within 12 hours (reasonable up to 24 hours). 1, 2
• If angiographic evidence of thrombus is present, initiate anticoagulation with heparin followed by warfarin for at least 3 months, regardless of thrombolytic use. 2, 5

If Chronic/Incidental Finding:

Proceed with medical management as outlined below. 1, 2

Medical Management (First-Line Treatment)

Start aspirin 75-325 mg daily immediately—this is the cornerstone of therapy and should be continued indefinitely. 1, 2, 5

Alternative antiplatelet regimens if aspirin is contraindicated:

• Clopidogrel 75 mg daily 1, 2
• Aspirin plus extended-release dipyridamole (25 mg/200 mg twice daily) reduced vertebrobasilar territory stroke/TIA from 10.8% to 5.7% compared to placebo 3, 1, 2

Critical pitfall to avoid: Do not use dual antiplatelet therapy (aspirin + clopidogrel) routinely—the hemorrhage risk outweighs any benefit in this setting. 1

Aggressive Risk Factor Modification

Treat according to the same standards as extracranial carotid atherosclerosis:

• Statin therapy for lipid management 3, 5
• Blood pressure control 3
• Diabetes management if present 3
• Smoking cessation 3

When to Consider Revascularization

Revascularization should only be pursued after medical therapy fails in patients with persistent or recurrent posterior circulation ischemic symptoms despite optimal medical management. 1, 2, 5

Before any revascularization attempt:

• Catheter-based contrast angiography is mandatory, as neither MRA nor CTA reliably delineates vertebral artery origins. 1, 2, 5

Revascularization Risks You Must Discuss:

Endovascular treatment carries significant risks:

• Death: 0.3% 1, 2, 5
• Periprocedural neurological complications: 5.5% 1, 2, 5
• Posterior stroke at 14.2 months: 0.7% 1, 2
• Restenosis at mean 12-month follow-up: 26% (though not consistently correlated with recurrent symptoms) 3, 1, 2, 5

Surgical options include trans-subclavian vertebral endarterectomy, vertebral artery transposition to the ipsilateral common carotid artery, or reimplantation with vein graft extension, with early complication rates of 2.5-25% and perioperative mortality of 0-4%. 3, 2, 5

Surveillance Strategy

Serial noninvasive imaging of the extracranial vertebral arteries is reasonable at intervals similar to those for carotid revascularization to assess disease progression and exclude new lesions. 3, 2, 5

Recommended schedule:

• 1 month post-diagnosis 3
• 6 months 3
• Annually thereafter 3

Once stability is established over an extended period, surveillance at extended intervals may be appropriate. 3

Critical Clinical Scenarios to Monitor

Watch for symptoms of posterior circulation ischemia:

• Vertigo, diplopia, ataxia, bilateral sensory deficits, syncope 5
• Occipito-cervical headache (often precedes cerebellar or medullary infarction) 4
• Wallenberg's syndrome 4

The vital risk in vertebral artery occlusion is not negligible—mortality was 25% in a series of 160 cases, with segmental distal and extensive occlusions carrying worse prognosis than proximal segmental occlusions. 4

Atheroembolism from vertebral artery origin lesions may cause brainstem or cerebellar infarction even when the contralateral vertebral artery is patent, so symptom monitoring is essential regardless of contralateral vessel status. 3, 2