Subclavian artery stenosis is a partial or complete occlusion of the unnamed artery or the proximal end of the subclavian artery before it divides into the vertebral artery, which causes a reverse flow of blood from the affected vertebral artery to supply the ischemic upper limb in reverse due to siphoning, resulting in ischemic attack of the vertebrobasilar artery and ischemic symptoms of the affected upper limb. Main symptoms 1. Dizziness: The most frequent symptom in patients with subclavian artery stenosis is transient ischemic attack, which manifests as sudden onset of dizziness, weakness or numbness of one side of the face or limb, or speech difficulty for a short period of time, blackness in front of the eyes (often a transient blackness of one eye), or transient loss of consciousness, amnesia, etc.