Arteries that supply blood to the arm and hand may also provide some blood to the brain. If a blockage occurs in the subclavian or innominate artery proximal to the origin of the vertebral artery (which supplies blood to the posterior part of the brain), the blood supply to both the arm and posterior part of the brain can be affected. What can happen is a stealing of blood from the brain as you exercise your arm. This is called a subclavian steal syndrome and can be noted as difficulty with walking (gait), loss of vision in part of the eye, sensory or motor problems in one half of the body, or other vision, or speech problems with or without arm pain and healing problems (especially in the fingers). If the narrowing in the arteries that supply blood to arm occurs distal to the vertebral arteries, then only the arm blood supply is affected and only arm or hand symptoms are noted. The diagnosis can be confirmed by a blood pressure study of the arm (upper extremity arterial doppler study). Angiography is generally necessary to provide a precise map of any blood vessel blockage(s) (Figure 1 A and 1 B). 

In some cases, balloon dilation with or without stent placement can open the vessel. In other cases, a bypass operation designed to jump over the area of blockage is required. This bypass operation is generally performed using your own vein as the substitute artery (Figure 2).