II. Epidemiology
- Age over 55 years
- More common in men than women by ratio of 2 to 1
III. Risk Factors
- Vigorous Exercise of affected extremity
- Similar to Cardiac Risk Factor
IV. Pathophysiology
- Proximal subclavian artery Occlusion
- Vertebral Artery supplies retrograde flow
- Results in decreased Blood Flow to posterior brain
V. Causes
- Arteriosclerosis of subclavian artery (95% of cases)
- Dissecting Aortic Aneurysm
- Embolism
- Takayasu's Arteritis
VI. Symptoms
- Vertebrobasilar Insufficiency
- Subclavian Insufficiency (onset after CNS symptoms)
- Arm weakness
- Arm coldness or Paresthesias
- Arm Claudication with Exercise
- Provocative Maneuvers
- Vigorous Exercise of affected arm
- Sudden turning of head to affected side
VII. Signs
- Diminished radial and ulnar pulses on affected side
- Blood Pressure difference >20 mmHg between arms
- Subclavian bruit
- Radial pulse disappears on arm Exercise or elevation
VIII. Radiology
- Carotid Ultrasound
- Magnetic resonance angiography
- Arch Aortography
IX. Management: Surgical Options
- Axillo-axillary bypass
- Carotid-Subclavian bypass
- Percutaneous transluminal Angioplasty with stenting
X. Prevention
- See Hypertension Management
- See Diabetes Mellitus Management
- Tobacco Cessation
XI. References
- Chan-Tack (2001) South Med J 94:445-7