What does Subclavian Steal Syndrome result from?

• A. Blockage of the distal subclavian artery
• B. Reversed blood flow due to proximal subclavian artery obstruction
• C. A rupture of the vertebral artery
• D. Blood clots forming in the cerebral circulation

Answer: (B)

Subclavian Steal Syndrome arises primarily due to an obstruction or stenosis at the proximal subclavian artery. When there is significant narrowing in this area, it creates a pressure gradient that causes blood to flow in a reversed direction through the vertebral artery. This phenomenon occurs because the body compensates for the reduced blood flow to the arm (supplied by the subclavian artery) by drawing blood from the vertebral artery, which typically supplies blood to the posterior circulation of the brain. As a result, patients may experience symptoms such as dizziness or symptoms of vertebrobasilar insufficiency due to this altered blood flow.

The mechanics behind this syndrome highlight the importance of the vascular connections between the subclavian artery and the vertebral artery, illustrating how vascular abnormalities in one area can significantly impact blood flow dynamics throughout the body.