43 Vertebral Artery Stenosis with Ischemia

Case 43 Vertebral Artery Stenosis with Ischemia

Glenn C. Hunter and Rudiger Von Ritschl

Fig. 43.1 Angiogram demonstrating the aortic arch and takeoffof the carotid, subclavian, and ver tebral ar teries. (A) More distal views demonstrating the left carotid bifurcation (B) and left vertebral artery (LVA) with collaterals (C) and (D). (TC, thyrocervical trunk.)

Clinical Presentation

A 56-year-old man with known hypertension and type 2 diabetes mellitus presents with a 6- to 9-month history of inability to raise his head or get out of bed. Any attempt to raise his head was accompanied by light headedness, dizziness, blurred vision, and drop attacks. His symptoms had become so severe that he was currently housebound.
Physical examination revealed a healthy appearing man with blood pressure of 150/90 in both arms and bilateral carotid bruits.

Questions

What is the differential diagnosis?

What tests would you obtain?

A carotid duplex scan is obtained. The scan demonstrates bilateral internal carotid occlusion and no antegrade vertebral flow in the neck. Does this finding always indicate vertebral artery occlusion?

You have a choice between ordering magnetic resonance imaging (MRI)/magnetic resonance angiography (MRA) or a conventional cerebral angiogram. What factors should you consider in making the decision?

Given the severe nature of the occlusive disease on the duplex scan, one would assume that symptoms in patients with vertebrobasilar (V-B) insufficiency are most frequently due to hypoperfusion. Is this assumption correct?

A four-vessel angiogram is obtained. Describe the angiographic findings (Fig. 43.1).
How would your management differ if there was 80–99% carotid stenosis with vertebral artery occlusion?
What are the operative procedures for V-B insufficiency?
What alternative interventional therapies are available?
What is the medical management of the inoperable patient?
How would you treat this patient?

Answers

What is the differential diagnosis?

Cardiac arrhythmias
Postural hypotension
V-B insufficiency
Hypoglycemia
Hypovolemia
Hyperventilation

What tests would you obtain?

Cardiac evaluation – electrocardiogram (EKG), cardiac echography, Holter monitoring

Routine blood chemistries – electrolytes, blood glucose, complete blood count (CBC), coagulation profile

Vascular imaging studies – Carotid duplex scan, transcranial Doppler

Cerebral imaging studies – MRI/MRA, computed tomography (CT), or conventional angiogram.1
A carotid duplex scan is obtained. The scan demonstrates bilateral internal carotid occlusion and no antegrade vertebral flow in the neck. Does this finding always indicate vertebral artery occlusion?
- The absence of antegrade flow in one or both vertebral arteries is not diagnostic of occlusion. Anatomic variations include arch origin and hypoplasia of the vertebral arteries.²
You have a choice between ordering an MRI/MRA or a conventional cerebral angiogram. What factors should you consider in making the decision?
- MRA is more effective in the diagnosis of basilar artery lesions than extracranial vertebral artery (ECVA) or intracranial vertebral artery (ICVA) disease.
- Four-vessel cerebral angiography is the investigation of choice depending on the cause of symptoms. It is less valuable in thromboembolism of cardiac origin.
Given the severe nature of the occlusive disease on the duplex scan, one would assume that symptoms in patients with V-B insufficiency are most frequently due to hypoperfusion. Is this assumption correct?
- No – the main causes of V-B insufficiency are listed below in order of frequency^1,3:
  - Large vessel embolism 41%
  - Hemodynamic causes 33%
  - Cardiac embolism 24%
A four-vessel angiogram is obtained. Describe the angiographic findings (Fig. 43.1).
- The angiogram shows bilateral ECVA and common carotid artery (CCA) occlusion with reconstitution of the distal ECVA.
- There is reconstitution of the left carotid bifurcation and 60% internal carotid artery (ICA) stenosis.
How would your management differ if there were 80–99% carotid stenosis with vertebral artery occlusion?
- The efficacy of treating concomitant asymptomatic occlusive disease is controversial.
  - If there is high grade 70–99% bilateral or unilateral symptomatic ICA stenosis then carotid endarterectomy (CEA) is done first.
  - The symptomatic hemisphere or dominant hemisphere in asymptomatic patients is treated first.
What are the operative procedures for V-B insufficiency?
- CEA
- Carotid subclavian bypass
- Vertebral artery endarterectomy or bypass⁴
What alternative interventional therapies are available?
- Carotid and vertebral artery angioplasty and stenting^3,5,6
- ECVA and ICVA angioplasty and stenting^3,5,6
- Use of thrombolytic agents³
What is the medical management of the inoperable patient?
- Control risk factors for atherosclerosis
- Optimize blood pressure control
- Warfarin (Coumadin; Bristol-Myers Squibb, New York, NY) for obstructive lesions amenable to surgery or endovascular therapy³
- Tissue plasminogen activator (TPA) and Abciximab³
- Aspirin/clopidogrel (Plavix; Bristol-Myers Squibb, New York, NY) after stenting³
How would you treat this patient?
- The patient was treated with a left subclavian to carotid bifurcation bypass using polytetrafluoroethylene (PTFE) graft and standard endarterectomy of the bifurcation with resolution of his symptoms.