Vascular Conditions

Subclavian Artery Steal Syndrome

Subclavian Steal Syndrome is a blockage of the subclavian artery which delivers blood to the arms and brain. The artery is located just under the collarbone, and when clogged, causes blood to flow backward. The arm essentially “steals” blood flow intended for the brain.


  • Slurred speech; difficulty talking; difficulty understanding words
  • Weakness or numbness of the face or body, usually affecting only one side
  • Inability to move limbs
  • Difficulty with vision in one or both eyes
  • Loss of balance
  • Sudden, severe headache and dizziness
  • Vertigo
  • Spontaneously falling to the ground from a standing position, usually without loss of consciousness


The main factor leading to subclavian steal is atherosclerotic arterial disease which causes subclavian artery occlusion or severe stenosis. In most cases, this occurs in the left side. If present on the right side, innominate artery disease or occlusion is the likely culprit.

The risk factors for developing this condition are categorized as either nonmodifiable (can’t change) or modifiable (able to change). Nonmodifiable risk factors include:

  • Age
  • Male sex
  • Family history

Modifiable risk factors that can be controlled or managed include:

  • Smoking
  • High cholesterol
  • Diabetes
  • Hypertension
  • Hyperhomocysteinemia

Although blood flow reversal is usually associated with artery occlusion, subclavian steal may also occur with significant stenosis.

Other, less common causes of this disease include Takayasu or giant cell arteritis. Congenital anomalies may result in isolation of the subclavian artery as well, and it can at times be an outcome of aortic surgery.


This condition can be diagnosed by a physical examination combined with the following tests:

  • Carotid Artery Ultrasound
  • Magnetic Resonance Imaging (MRA)
  • Carotid Artery Angiogram
  • Computed Tomographic Angiography (CTA)
  • Angiography


While you can’t do anything about your age, sex, and family history, you can make lifestyle choices and manage other conditions to lower your risk of Subclavian Steal Syndrome.

  • Quit smoking
  • Get high blood pressure under control
  • Manage your Diabetes
  • Lower cholesterol
  • Consider Angiography with angioplasty/stent
  • Elect to have Carotid Endarterectomy Surgery