17.1 Goals

1. 
   

   Review the literature that forms the basis of our understanding of the natural history of vertebral artery stenosis.

   
   
2. 
   

   Review the literature that supports treatment of vertebral artery origin stenosis.

   
   
3. 
   

   Critically analyze the literature on the natural history of vertebral origin stenosis and evidence-based decisions regarding management.

17.2 Case Example

17.2.1 History of Present Illness

A 66-year-old male presented to the emergency department with dizziness which he described as balance issues and a spinning sensation with exertion. He denied any other complaints and his physical examination was unremarkable. The patient was on daily aspirin (ASA) and clopidogrel due to previous cardiovascular history and risk factors. Imaging assessment with noncontrast computed tomography of the head was negative for ischemic and hemorrhagic stroke. Magnetic resonance imaging showed subacute cerebellar infarction. Computed tomography angiogram (CTA) of the head and neck revealed severe stenosis of the right vertebral artery ostium. The left vertebral artery was occluded at the origin. Both carotid arteries were patent. He was then transferred to a comprehensive stroke center for further management. Past medical history: Coronary and peripheral artery disease, hypertension, diabetes type II, hyperlipidemia, and atrial fibrillation (treated with cardioversion, denied use of anticoagulation).

Past surgical history: Coronary and peripheral artery stenting, bilateral carotid endarterectomies.

Family history: Denies cardiovascular events in the family.

Social history: Denies tobacco smoking, alcohol abuse, or illicit drugs.

Neurological examination: Unremarkable.

Imaging studies: See Fig. 17.1 and Fig. 17.2.

17.3 Case Summary

1. 
   

   What are the indications for vertebral artery stenting? In patients with vertebrobasilar insufficiency, revascularization of the vertebral artery origin can be considered if degree of stenosis is significant. Even though vertebral artery origin stenting is a relatively safe procedure, the evidence of its superiority over medical management is lacking. When reviewing literature, VAOS stenting should also be separated from intracranial vertebral artery stenting as intracranial stenting has been shown to have higher rate of preprocedural risks likely due to its anatomy, location, and presence of perforators. A recent meta-analysis of the stenting versus medical management for vertebral artery stenosis showed high risks of periprocedural stroke or death for intracranial stenting and did not demonstrate any evidence of benefit for stenting over medical management in extracranial stenosis. It should be noted that the number of extracranial stenosis were small, and no randomized study, as of today, has looked exclusively at the vertebral artery origin stenosis (VAOS). ¹

   
   

   Previous retrospective studies, however, have shown that VAOS stenting is feasible and relatively safe. Selection of appropriate patients with vertebrobasilar disease due to VAOS and no other causes is also very important. A detail history, clinical examination, and imaging are key. Patients with unilateral vertebral artery disease and contralateral vertebral artery hypoplasia or bilateral vertebral artery disease may be at higher risk of thromboembolic events. Advanced imaging, such as large-vessel quantitative magnetic resonance angiography (QMRA), can be used to select patients with poor posterior circulation flow.

   
   
2. 
   

   What are the symptoms of vertebrobasilar insufficiency? Ischemia in the vertebrobasilar circulation can result in a wide variety of symptoms often occurring simultaneously. Symptoms include perioral numbness, vertigo, unilateral weakness, and visual disturbances. Other potential manifestations include syncopal episodes, nausea, vomiting, tinnitus, headache, dysarthria, ataxia, motor and sensory disturbances, and cranial nerves deficits.

   
   
3. 
   

   What are the risks of vertebral artery stenting?

   
   

   Periprocedural risks associated with vertebral artery stenting is low (1-3%) when performed by skilled operators. ² Inherent complications associated with endovascular manipulation of vessels are further embolization of atherosclerotic material causing strokes/transient ischemic attacks (TIAs), potential myocardial infarction, and death. The most frequent complication after stenting the vertebral artery is in-stent restenosis, which can be reduced by the use of drug-eluting stents. Fractures of the stent due to elastic recoil at the ostium may also occur. ³

   
   
4. 
   

   What patient factors were considered in the decision of revascularization versus medical treatment in this case?

   
   

   Even though the optimized management of the VAOS remains unclear, our patient in this case was thought to be a good candidate for revascularization. He had evidence of a prior cerebellar stroke. His contralateral vertebral artery was occluded and he did not have well-developed posterior communicating arteries or other evidence of collateral circulation. Therefore, he relied on the stenotic right vertebral artery to provide blood to the posterior circulation. Therefore, he underwent stent revascularization to reestablish blood supply to the vertebrobasilar system.

   
   
5. 
   

   What are the technical factors to consider for vertebral artery stenting?

   
   

   There are several technical aspects to consider when VAOS stenting is planned. Importantly, medical management should be optimized with dual antiplatelet therapy and statin, if indicated. Dual antiplatelet regimen is typically continued for at least 6 months poststenting. Access is also important, as these lesions lend themselves particularly well to the transradial approach. A balloon-mounted stent is typically used, and drug-eluting stents may decrease risk of in-stent stenosis. While placing the stent, it is important to cover the entire vertebral artery origin as the diseased area is typically at the ostium.