Vertebral basilar artery insufficiency

Q: Can my dizziness be due to vertebrobasilar artery insufficiency?

It is possible, but the most common causes of dizziness are peripheral causes, such as benign paroxysmal positional vertigo (BPPV) or vestibular neuritis. Dizziness caused by VBI is most often accompanied by other brainstem symptoms such as double vision, dysarthria, dysphagia, and limb paralysis. However, in approximately 20% of cases, dizziness may be the only symptom, so careful evaluation is necessary in elderly patients with vascular risk factors [5].

Q: Is it VBI that makes you dizzy when you turn your neck?

In the past, it was explained that ischemia occurs due to physical compression of the vertebral artery during neck rotation (bow hunter syndrome), but this is a very rare condition. Most cases of dizziness when rotating the neck are due to BPPV, cervical dizziness, or vestibular dysfunction. If VBI is suspected, it should be confirmed with vascular imaging (MRA/CTA).

Q: Can VBI lead to a stroke?

Transient symptoms of VBI (posterior circulation TIA) may be a precursor to a stroke. The risk of stroke within 90 days after a posterior circulation TIA is approximately 10-15% and is similar to that of anterior circulation TIA [1]. Therefore, immediate medical evaluation is necessary if symptoms of VBI are suspected.

Q: How to prevent VBI?

Active management of vascular risk factors such as high blood pressure, diabetes, hyperlipidemia, and smoking is key. Administration of antiplatelet drugs (aspirin, clopidogrel) is used to prevent recurrence, and if atrial fibrillation is present, anticoagulant treatment is required [1].

Q: Is stent surgery performed for vertebral artery stenosis?

Although endovascular stenting for symptomatic vertebral artery stenosis is technically feasible, there was insufficient evidence from randomized controlled trials (VIST) to demonstrate that stenting is superior to medical treatment alone in preventing stroke recurrence [4]. Currently, drug treatment is the first line of treatment.

At a glance

VBI is a blood flow disorder of the posterior circulation, and its characteristic symptoms include dizziness, double vision, dysarthria, and loss of balance. Posterior circulation stroke accounts for approximately 20-25% of all ischemic strokes, and its initial mortality rate is higher than that of the anterior circulation [1]. Vertebral artery atherosclerosis is the most common cause, and management of vascular risk factors and antithrombotic treatment are the keys to prevention [2].

Definition and Overview

Vertebrobasilar insufficiency (VBI) is a condition in which ischemia occurs in the brainstem, cerebellum, thalamus, and occipital lobe perfused by these arteries due to decreased blood flow in the vertebral artery or basilar artery.

Posterior circulation ischemia accounts for approximately 20 to 25% of all ischemic strokes and 25 to 30% of TIAs. Posterior circulation stroke tends to be diagnosed later than anterior circulation, and the initial mortality rate of brainstem infarction is approximately 20-30%, which is higher than that of anterior circulation.

cause

atherosclerosis

Atherosclerotic stenosis of the origin of the vertebral artery is the most common cause. Atherosclerosis of the intracranial vertebral artery and basilar artery is also a major cause.

embolism

Emboli originating from the heart (atrial fibrillation, valvular disease) or aortic arch may travel to the posterior circulation and occlude blood vessels.

arterial dissection

Vertebral artery dissection is an important cause of posterior circulation stroke in young people. Hyperextension and rotation of the neck, chiropractic manipulation, and trauma are triggering factors.

small vessel disease

Small vessel disease of the perforating artery within the brainstem causes lacunar infarction.

Other causes

Subclavian steal syndrome, vasculitis, coagulopathy, and fibromuscular dysplasia rarely cause VBI.

symptoms

Transient symptoms (TIA)

Typical symptoms of posterior circulation TIA include:

Vertigo: the most common symptom, but when isolated, the likelihood of VBI is low.
Diplopia: Ischemia of the brainstem oculomotor nuclei or their connecting pathways.
dysarthria: slurred speech
dysphagia: difficulty swallowing
Ataxia: Balance disorder and gait instability caused by cerebellar ischemia
Bilateral or alternating hemiparesis/paresthesia
Temporary visual disturbance: ipsilateral visual field defect in both eyes

Warning signs of brainstem ischemia

According to the Oxford study, approximately 60% of patients with posterior circulation stroke experienced transient brainstem symptoms before the stroke, many of which were mild dizziness or double vision.

diagnosis

vascular imaging

MRA (magnetic resonance angiography): It is the primary test to noninvasively evaluate stenosis, occlusion, and dissection of the vertebral-basilar artery.
CTA (CT angiography): Complementary to MRA and excellent for evaluating calcified atheroma.
Digital subtraction angiography (DSA): The gold standard, but because it is invasive, it is primarily used when planning interventional procedures.

brain imaging

Brain MRI (including DWI): Sensitively detects acute brainstem and cerebellar infarction. CT has limitations in evaluating posterior fossa lesions, so MRI is preferred.

heart test

Evaluate causes of cardiogenic emboli, such as atrial fibrillation and valvular disease, through electrocardiogram, 24-hour Holter monitor, and echocardiography.

Differential diagnosis

If dizziness is the main symptom, it is important to differentiate it from peripheral vestibular disease.

BPPV: triggered by position change, positive Dix-Hallpike test, no neurological abnormalities.
Vestibular neuritis: Acute persistent dizziness, nystagmus, unilateral decrease in vestibular function
Meniere's disease: Recurrent dizziness + ear fullness + hearing loss + tinnitus
VBI: accompanied by brainstem symptoms, presence of vascular risk factors, vascular abnormalities on imaging

The HINTS test (Head Impulse, Nystagmus type, Test of Skew) has been reported to be more sensitive than MRI in distinguishing between central and peripheral acute dizziness.

treatment

medical treatment

The primary treatment for posterior circulation ischemia is medical treatment.

Antiplatelet agents: aspirin or clopidogrel in non-cardiac causes.
Anticoagulant treatment: NOACs or warfarin for psychogenic causes such as atrial fibrillation.
Management of vascular risk factors: hypertension (goal <130/80 mmHg), hyperlipidemia (statins, LDL <70 mg/dL), diabetes, smoking cessation.

endovascular treatment

Stenting for symptomatic vertebral artery origin stenosis is technically feasible, but the superiority of stenting over optimal medical treatment has not been demonstrated in the VIST study. Current guidelines recommend limited consideration in cases of drug treatment failure.

acute care

In posterior circulation acute stroke, as in anterior circulation, intravenous thrombolysis (IV tPA) within 4.5 hours of onset and mechanical thrombectomy in case of large vessel occlusion are applied. In basilar artery occlusion, mechanical thrombectomy may be considered up to a longer time window (up to 24 hours) after onset.

prognosis

Aggressive medical treatment after posterior circulation TIA can significantly reduce the risk of stroke within 90 days. However, when brainstem infarction occurs, the prognosis varies greatly depending on the area and extent of the infarction, and basilar artery occlusion has a mortality rate of 85-95% without treatment.

Frequently asked questions

Q01Can my dizziness be due to vertebrobasilar artery insufficiency?

It is possible, but the most common causes of dizziness are peripheral causes, such as benign paroxysmal positional vertigo (BPPV) or vestibular neuritis. Dizziness caused by VBI is most often accompanied by other brainstem symptoms such as double vision, dysarthria, dysphagia, and limb paralysis. However, in approximately 20% of cases, dizziness may be the only symptom, so careful evaluation is necessary in elderly patients with vascular risk factors [5].

Q02Is it VBI that makes you dizzy when you turn your neck?

In the past, it was explained that ischemia occurs due to physical compression of the vertebral artery during neck rotation (bow hunter syndrome), but this is a very rare condition. Most cases of dizziness when rotating the neck are due to BPPV, cervical dizziness, or vestibular dysfunction. If VBI is suspected, it should be confirmed with vascular imaging (MRA/CTA).

Q03Can VBI lead to a stroke?