What are the symptoms and treatment options for left vertebral artery hypoperfusion near the basilar junction?

Symptoms of Left Vertebral Artery Hypoperfusion Near Basilar Junction

Left vertebral artery hypoperfusion near the basilar junction typically presents with dizziness, vertigo, diplopia, perioral numbness, blurred vision, tinnitus, ataxia, bilateral sensory deficits, and syncope, which can significantly impact mortality and morbidity if not properly identified and treated. 1

Clinical Presentation

Symptoms of left vertebral artery hypoperfusion near the basilar junction include:

• Common symptoms:

  • Dizziness and vertigo
  • Diplopia (double vision)
  • Perioral numbness
  • Blurred vision
  • Tinnitus
  • Ataxia (impaired coordination)
  • Bilateral sensory deficits
  • Syncope (fainting)

• Less common but significant symptoms:

  • Headache
  • Nausea and vomiting
  • Hearing loss
  • Slurred speech
  • Imbalance
  • Unilateral extremity weakness 1

• Specific syndromes based on location:

  • Top of the basilar syndrome: somnolence, peduncular hallucinosis, convergence nystagmus, skew deviation, oscillatory eye movements, and vertical gaze paralysis
  • Mid-basilar occlusions: various pontine syndromes
  • Proximal basilar occlusions: "locked in" syndrome 1

Diagnostic Challenges

It's important to note that these symptoms can be misleading for several reasons:

1. They can mimic other conditions including cardiac arrhythmias, orthostatic hypotension, and vestibular disorders 1
2. The NIHSS (National Institutes of Health Stroke Scale) has limitations in detecting posterior circulation strokes, as it focuses more on limb and speech impairments than on cranial nerve lesions 1
3. Patients with posterior circulation large vessel occlusion can have an NIHSS score of 0, presenting only with headache, vertigo, and nausea 1
4. Hypoperfusion symptoms alone correlate poorly with actual hemodynamic compromise as assessed by quantitative magnetic resonance angiography 2

Diagnostic Approach

For accurate diagnosis of left vertebral artery hypoperfusion:

1. Imaging studies:

   • CTA and contrast-enhanced MRA have higher sensitivity (94%) and specificity (95%) than ultrasonography (sensitivity 70%) 1
   • Neither MRA nor CTA reliably delineates the origins of the vertebral arteries 1
   • Catheter-based angiography is typically required before revascularization for patients with symptomatic posterior cerebral ischemia 1
   • High-resolution MRI may detect dissection even when routine MRI is negative 3
   • Arterial spin labeling (ASL) can help identify hypoperfusion 3

2. Additional diagnostic tests:

   • Bilateral arm blood pressure measurement (difference ≥15 mmHg is suspicious for subclavian steal syndrome) 4
   • Duplex ultrasonography to identify reversal of flow in vertebral artery 4

Treatment Options

Treatment for left vertebral artery hypoperfusion should be tailored based on etiology:

1. Medical management:

   • For acute ischemic syndromes with angiographic evidence of thrombus in the extracranial vertebral artery, anticoagulation is generally recommended for at least 3 months 1, 4
   • The WASID trial found aspirin and warfarin to be equally efficacious after initial noncardioembolic ischemic stroke 1
   • Ticlopidine has shown superiority to aspirin for secondary prevention of ischemic events in patients with symptomatic posterior circulation disease 1
   • Aggressive cardiovascular risk factor modification is recommended 4

2. Revascularization options:

   • Indications for revascularization:

     • Recurrent ischemic symptoms
     • Progression to preocclusive severity 1
     • TIA/stroke
     • Severe upper extremity ischemia 4

   • Surgical options:

     • Carotid-subclavian bypass (100% success rate, 96% patency at 5 years)
     • Subclavian-carotid arterial transposition
     • Carotid-axillary or axilloaxillary bypass 4

   • Endovascular approach:

     • Angioplasty with or without stenting
     • Lower complication rates compared to surgery
     • Primary patency rates of 93% at 1 year and 70% at 5 years 4

Follow-up and Prognosis

• Regular follow-up with serial noninvasive imaging at 1 month, 6 months, and annually after intervention 4
• Long-term aspirin after surgical bypass and dual antiplatelet therapy for at least 30 days after endovascular stenting 4
• Without treatment, posterior circulation strokes have a mortality range from 45% to 86% 1
• Predictors of poor outcome include older age, higher NIHSS score, lack of recanalization, atrial fibrillation, intracranial hemorrhage, and posterior circulation Alberta Stroke Program Early CT Score (pc-ASPECTS) ≤8 1

Important Caveats

1. Vertebrobasilar arterial stenosis is associated with multiple ischemic episodes and a higher risk of early recurrent stroke 1
2. Isolated unilateral vertebral artery stenosis can cause incapacitating vertebrobasilar insufficiency, contrary to traditional belief 5
3. Transient neurological attacks with nonfocal symptoms (especially isolated vertigo) may represent TIAs due to vertebrobasilar circulation ischemia 6
4. Patients with prior transient neurological attacks have a significantly higher rate of atherothrombotic stroke than those without 6