subclavian steal syndrome

Other important cardio-vascular conditions that can be manifested by syncope include subclavian steal syndrome and aortic stenosis.

In subclavian steal syndrome, blood is "stolen" from the Circle of Willis to preserve blood flow to the upper limb.

Subclavian steal syndrome results from a proximal stenosis (narrowing) of the subclavian artery, an artery supplied by the aorta which is also the same blood vessel that eventually feeds the Circle of Willis via the common carotid artery.