The subclavian arteries are pipes that carry blood rich in oxygen from your heart to your arms and the back of your brain. Subclavian artery disease develops when blood flow is decreased because a section of one of these arteries has become narrow or is blocked. This blockage is often caused by the buildup of plaque—fat, cholesterol and other substances—also called atherosclerosis.
If you have subclavian artery disease, you have a higher chance of developing this buildup in other arteries throughout your body, which can lead to a heart attack, chest pain, stroke or cramping (claudication) in the legs. In some cases, the blockage can be caused by birth defects, radiation exposure, or pressure on the artery from outside sources.
Subclavian artery disease is a form of peripheral arterial disease (PAD), which involves blockages in arteries outside of your heart. However, the blood vessels of the upper body are affected less often. About 3% of the general population has subclavian artery disease, and in those with PAD, the percentage is 11%.
Often, subclavian artery disease does not cause any symptoms because the disease progresses slowly or the body creates blood vessels around the blockage to maintain flow—or both. The symptoms that do occur are tied to the area that is blocked. You may experience arm pain or muscle fatigue when using your arms above your head, or doing any activity that demands more oxygen-rich blood flow to the arms. Other symptoms can include:
- Dizziness (vertigo) with arm activity
- Feeling as if you might pass out
- Blurred, double or partial loss of vision
Your health care professional may suspect subclavian artery disease if the top number of your blood pressure differs greatly between both arms (more than 20 mm Hg). The pulses in both of your arms will be compared as well as the temperature of your skin. In severe cases, your fingers may change colors and have pain without activity. Imaging tests to examine the blood flow in the subclavian artery and lab work often will be ordered.
Subclavian artery disease is often caused by a buildup of plaque—fat, cholesterol and other substances (also called atherosclerosis)—in one of the subclavian arteries. There are two of these: a right subclavian artery and a left subclavian artery that supply blood to your upper body.
The left subclavian artery branches off of the aorta, which is a large blood vessel that starts at the heart and travels into the abdomen. Another artery branches off the aorta on the right (called the brachiocephalic artery) and divides into the right subclavian artery and the right common carotid artery.
Other causes of subclavian artery disease include:
- Inflammation of the arteries
- Fibromuscular dysplasia (a disease that causes abnormal cell or tissue buildup in the wall of the artery)
- Radiation exposure to the neck, chest or both
- Birth defects
- Neurofibromatosis (growth of tumors on nerve tissue)
Only a few signs aid your physician in diagnosing this condition. A lower blood pressure reading when using the arm on the side where the artery is blocked is a strong sign of subclavian artery disease. If your health professional suspects you have a blockage, it is important to have your blood pressure checked in both arms. Any consistent blood pressure difference greater than 20 mm Hg suggests subclavian artery disease.
The presence of a harsh noise heard with a stethoscope over the blood vessel involved can be another sign of disease and obstruction.
If you have subclavian artery disease, the symptoms you experience depend largely on the artery involved and the degree of blockage. Symptoms may reflect a lack of blood flow to the area being supplied, such as:
- Arm or hand pain with activity (claudication)
- Numbness (paresthesia)
- Pain while resting
- Discoloration of the fingers, hands and/or arm
Some patients don’t have symptoms because the body adapts in response to the obstruction and can create new blood vessels that go around the blockage.
When the artery that branches from the subclavian artery and supplies the back of the brain is affected, you may experience symptoms of less blood flow to the back of the brain. You may have dizziness, a hard time walking or poor balance.
Exercising the arm affected by the narrowed subclavian artery causes more blood to be sent to the arm instead of the brain. This is called subclavian steal syndrome. Your health care professional may suspect this syndrome if when using your arms you experience:
- Fainting (syncope)
- Dizziness (vertigo)
- Difficulty walking
- Blurred or double vision
- Arm tiredness or discomfort
Some simple tests may help identify this syndrome.