Subclavian Steal Syndrome
Atherosclerosis is the most common cause of subclavian steal syndrome. This is more common on the left side, due to a more acute origin of the left subclavian artery. Subclavian steal syndrome is a constellation of signs and symptoms that arise from retrograde blood flow in the vertebral artery or the internal thoracic artery. This is due to a proximal stenosis and/or occlusion of the subclavian artery. The arm may be supplied by blood flowing in a retrograde direction downward to the vertebral artery at the expense of the vertebrobasilar circulation. This is called the subclavian steal. It is more severe than typical vertebrobasilar insufficiency.