II. Epidemiology

  1. Age over 55 years
  2. More common in men than women by ratio of 2 to 1

III. Risk Factors

IV. Pathophysiology

  1. Proximal subclavian artery Occlusion
  2. Vertebral Artery supplies retrograde flow
  3. Results in decreased blood flow to posterior brain

V. Causes

  1. Arteriosclerosis of subclavian artery (95% of cases)
  2. Dissecting aortic aneurysm
  3. Embolism
  4. Takayasu's Arteritis

VI. Symptoms

  1. Vertebrobasilar Insufficiency
    1. Light-headedness or Dizziness
    2. Ataxia or Vertigo
    3. Visual disturbance
    4. Motor deficit
    5. Confusion
    6. Focal Seizure
    7. Aphasia
    8. Headache
    9. Syncope
  2. Subclavian Insufficiency (onset after CNS symptoms)
    1. Arm weakness
    2. Arm coldness or Paresthesias
    3. Arm Claudication with Exercise
  3. Provocative Maneuvers
    1. Vigorous Exercise of affected arm
    2. Sudden turning of head to affected side

VII. Signs

  1. Diminished radial and ulnar pulses on affected side
  2. Blood Pressure difference >20 mmHg between arms
  3. Subclavian bruit
  4. Radial pulse disappears on arm Exercise or elevation

VIII. Radiology

  1. Carotid Ultrasound
  2. Magnetic resonance angiography
  3. Arch Aortography

IX. Management: Surgical Options

  1. Axillo-axillary bypass
  2. Carotid-Subclavian bypass
  3. Percutaneous transluminal Angioplasty with stenting

XI. References

  1. Chan-Tack (2001) South Med J 94:445-7

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