Subclavian Steal Syndrome

Subclavian Steal Syndrome is a condition that affects the blood vessels near the heart and neck, specifically the arteries supplying blood to the arms and brain. It occurs when one of the main arteries, called the subclavian artery, becomes narrowed or blocked, usually due to atherosclerosis. This blockage causes blood to flow backward in a nearby artery, stealing blood from the brain to supply the arm. As a result, people may experience symptoms like dizziness, arm weakness, or vision problems, especially when using the affected arm. The condition primarily involves the circulatory system and can impact brain function due to reduced blood flow. It is important to recognize because it can lead to serious complications like stroke or permanent neurological damage.

Subclavian Steal Syndrome is defined as a hemodynamic phenomenon caused by proximal subclavian artery stenosis or occlusion, leading to retrograde flow in the ipsilateral vertebral artery. This reversal of blood flow diverts blood from the posterior cerebral circulation to the upper extremity, resulting in cerebral hypoperfusion. The most common etiology is atherosclerotic plaque formation causing significant arterial narrowing. Clinically, it manifests with symptoms of vertebrobasilar insufficiency such as dizziness, syncope, or visual disturbances, often triggered by arm exertion. Physical exam may reveal a significant blood pressure difference (>15-20 mmHg) between arms and diminished pulses on the affected side. The syndrome is significant because it can cause transient ischemic attacks or stroke due to compromised posterior circulation.