From the arch, the aorta courses downwards to the chest and abdomen.
The subclavian arteries travel beneath the collar bones to supply blood to each arm.
Thus, with subclavian steal syndrome blood is effectively stolen from the brain to supply the blood-deficient arm.
Frank van Delft / Cultura / Getty Images
Often when subclavian steal is present, there may be no symptoms at all at rest.
But, if the blockage is large enough, two things can happen when the affected arm is exercised.
These symptoms most commonly appear when the arm is being exerted.
As the degree of blockage increases, symptoms occur with less and less arm exercise.
Diagnosis
To diagnose subclavian steal syndrome, the doctor first needs to look for it.
This may not happen unless the patient describes symptoms that suggest this diagnosis.
Once subclavian steal syndrome is thought of, however, it is usually not difficult to make the diagnosis.
Because there is partial blockage in a subclavian artery, the blood pressure in the affected arm is diminished.
So there is usually a large difference in blood pressure between the two arms.
The pulses in the affected arm are also diminished.
Atherosclerotic cardiovascular disease is a progressive disease that affects blood vessels throughout the body.
The symptoms of mild subclavian steal syndrome may improve with such measures.
If mild, the condition is often treated with risk factor modification.
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