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Vertebral artery stenosis and occlusion

General Information

Description:

  • Narrowing or obstruction of one or both vertebral arteries causing ischemic symptoms

Also called:

  • Vertebral artery stenosis
  • Posterior circulation stenosis/occlusion
  • Vertebrobasilar ischemia
  • Vertebrobasilar insufficiency

Types:

  • Extracranial
  • Intracranial

Organs involved:

  • Vertebral artery and additional components of posterior circulation
  • Brainstem or cerebellum may be affected
  • Vertebral artery can be divided into 4 sections, with V1 and V4 being most common stenotic sites
    • V1 - extracranial, prevertebral, and includes origin of vertebral artery
    • V2 - extracranial foraminal or cervical artery
    • V3 - extracranial postforaminal artery at atlanto-axial region
    • V4 - intracranial artery (includes junction with basilar artery)
    • Stenosis at origin or intracranial vertebral artery each reported in about 30% of patients with posterior circulation transient ischemic attack or stroke
      • Based on cohort study
      • 407 patients (mean age 61 years) with posterior circulation transient ischemic attack or stroke in prior 6 months had 443 vascular lesions evaluated
      • Stenosis > 50% occurred in
        • 131 lesions (30%) at vertebral artery origin (V1)
        • 132 lesions (30%) at intracranial vertebral artery (V4)
      • Reference - New England Medical Center Posterior Stroke trial (J Clin Neurol 2005 Apr;1(1):31)

Who is most affected?

  • White males for extracranial vertebral artery disease
  • For intracranial vertebral artery disease
    • Black patients
    • Patients of Asian origin
    • Women

Incidence/Prevalence:

  • Annual incidence of vertebrobasilar stenosis 13.5 patients/100,000 person-years in United Kingdom
    • Based on prospective cohort study
    • 141 patients with vertebrobasilar transient ischemic attack or minor stroke in Oxford Vascular Study had imaging of posterior circulation with contrast enhanced magnetic resonance angiography or computed tomography angiography
    • 37 patients (26.2%) had ≥ 50% symptomatic vertebral or basilar stenosis
    • Annual incidence of symptomatic vertebrobasilar stenosis was 13.5 patients/100,000 person-years
    • Reference - Oxford Vascular trial (Brain 2009 Apr;132(Pt 4):982), commentary can be found in Brain 2010 May;133(Pt 5):e140
  • 0.1% prevalence of incidentally-detected vertebral artery stenosis in adults from the Netherlands
    • Based on cross-sectional study
    • 2,000 adults ≥ 45 years old (mean age 63 years) from population-based Rotterdam Study who had magnetic resonance imaging (MRI) included
    • Incidental brain findings on MRI included
      • Vertebral artery stenosis in 0.1%
      • Major-vessel stenosis in 0.5%
    • Reference - Rotterdam trial (N Engl J Med 2007 Nov 1;357 (18):1821 ),

Causes and Risk Factors

Causes:

  • Atherosclerosis
  • Embolism (intra-arterial or cardiac)
  • Fibromuscular dysplasia
  • Cystic medial necrosis
  • Arteritis
  • Dissection
  • Penetrating artery disease

 

Pathogenesis:

  • Pathophysiology not well understood
  • Narrowing and/or blockage of vertebral arteries leads to reduced perfusion and increased risk for ischemic events including brainstem or cerebellar infarction
  • Atherosclerosis at vertebral artery origin associated with
    • Low burden of atheroma
    • High density of fibrous material
    • Low ulceration
    • Concentric geometry
  • Prothrombotic glycoprotein Ib alpha single nucleotide polymorphism may be associated with arterial stenosis in patients who smoke
    • Based on case-control study
    • 114 patients with symptomatic carotid or vertebral artery stenosis and 97 unrelated controls evaluated for platelet receptor gain-of-function single nucleotide polymorphisms
    • No significant differences overall in allele frequency for protease activated receptor 1 adenine/thymine, platelet collagen receptor cytosine/thymine, platelet glycoprotein IIb/IIa phosphoinositide homozygosity, or glycoprotein Ib thymine/cytosine
    • Significantly higher allele frequency of prothrombotic glycoprotein Ib alpha 5 C/T in subgroup of patients who smoke compared to controls (p = 0.04)
    • Reference - J Thromb Thrombolysis 2011 Aug;32(2):215

Likely risk factors:

  • Cardiovascular disease
  • Hyperlipidemia
  • Hypertension
  • Tobacco use
  • Diabetes mellitus (13)
  • Rates of vascular risk factors in patients with posterior transient ischemic attack or stroke in prior 6 months
    • Based on prospective cohort study
    • 407 adults (mean age 61 years) with posterior circulation transient ischemic attack and/or stroke in prior 6 months in New England Medical Center Posterior Circulation Stroke Registry
    • Rates of vascular lesions by location for 443 vascular lesions with > 50% stenosis
      • Intracranial vertebral artery for 29.8%
      • Vertebral artery origin for 29.6%
      • Basilar artery for 24.6%
      • Cerebral, cerebellar, Subclavian, innominate arteries for 16%

    • Rates of risk factors
      • Hypertension in 61%
      • Smoking in 36%
      • Coronary artery disease in 35%
      • Diabetes mellitus in 26%
      • Hyperlipidemia in 25%
      • Peripheral vascular occlusive disease in 10%
    • Reference - J Clin Neurol 2005 Apr;1(1):31
  • Prevalence of vertebral artery stenosis reported to increase with age
    • Based on 2 cross-sectional studies
    • Cross-sectional study of 936 patients having high-resolution contrast-enhanced magnetic resonance angiography at one institution to determine prevalence of stenosis at 3 anatomical sites
      • Stenosis prevalence overall
        • 12.9% proximal vertebral artery
        • 5.5% distal vertebral artery/basilar artery
        • 7.2% internal carotid artery
      • Prevalence of stenosis increased with age (p < 0.0001 for all arteries)
      • Reference - Acta Radiol 2005 May;46(3):314  
    • Cross-sectional study of 329 patients with digital subtraction angiography evaluated for vertebral artery origin stenosis in 443 vertebral arteries
      • Prevalence of vertebral artery origin stenosis
        • 5.4% overall
        • 12.5% in patients > 70 years old
        • 0% in patients < 40 years old
      • Reference - J Neuroimaging 2012 Jan 17 early online

Possible risk factors:

  • Prolonged abnormal posture of neck and compression of vertebral artery from prolonged telephone conversation leading to stroke in case report (CMAJ 2002 Nov 12;167(10):1104 full-text), commentary can be found in CMAJ 2003 Feb 18;168(4):400