Subclavian artery steal syndrome A significant stenosis or occlusion of the subclavian artery or the unnamed artery at the proximal end of the vertebral artery causes a reverse flow of blood from the ipsilateral vertebral artery into the subclavian artery due to siphoning, and the blood flow from the contralateral vertebral artery is also partially stolen and enters the subclavian artery via the affected vertebral artery to supply the affected upper limb, thus causing vertebral. The symptoms of insufficient blood supply to the basilar artery are known as subclavian artery steal syndrome. Atherosclerosis is the most common cause, followed by atopic and nonspecific arteritis. Pathological examination reveals atherosclerotic plaques, inflammation, luminal narrowing or occlusion in the beginning of the subclavian artery and the unnamed artery. There are more males than females, and more left-sided than right-sided. In severe cases, the blood of the internal carotid artery may be reversed through the posterior communicating artery and symptoms of ischemia of the internal carotid artery system, such as hemiparesis, hemianesthesia and aphasia, etc.; abnormal sensation, weakness, pale skin and muscle pain in the affected upper limbs, affected side The pulse of the radial artery is weakened, the blood pressure of the affected upper arm is lower than that of the healthy side by more than 20 mmHg, and murmurs can be heard in the supraclavicular fossa. Movement of the affected limb triggers or aggravates vertebral. Symptoms of basilar artery insufficiency can assist in the diagnosis; DSA can confirm the diagnosis. Treatment of stealsyndrome can be performed by endarterectomy. Case Male, 67 years old. He presented to the clinic with dizziness and vomiting for half an hour. The patient suddenly felt dizziness when waking up in the morning, unsteady standing and falling down, accompanied by nausea and vomiting, without headache and convulsions. He had a previous history of myocardial infarction. On examination: consciousness is clear, blood pressure is not measured (left upper limb), left radial artery pulsation is weak, face and lips are pale, breathing is slightly rapid, no abnormalities in both lungs, heart rate is 78/min, rhythm is uniform, heart sounds are low and dull. Consider shock. The blood pressure of the left upper limb was still 0mmHg after 30 minutes, and then the blood pressure of the right upper limb was 120/75mmHg. The hemogram of both upper limbs showed increased tension and decreased elasticity of the radial artery, and the wave amplitude was 20% less than that of the right radial artery. Color Doppler ultrasound showed that the proximal internal diameter of the left subclavian artery was about 0.62 cm, with a peak flow of 44 cm/s. The lumen of the left subclavian artery was partially narrowed near the left sternoclavicular joint, with an internal diameter of 0.25-0.45 cm and a length of about 2.5 cm; the luminal membrane was echogenic and gross, and the local blood flow was turbulent with a peak flow of 75 cm/s. The internal diameter of the left vertebral artery was about 0.16 cm, The internal diameter of the left vertebral artery was about 0.16 cm, the peak systolic flow (Vs) was 26 cm/s, the diastolic flow velocity (Vd) was 5 cm/s, the resistance index (RI) was 0.81, and the spectral pattern was normal with a reverse flow signal; the left upper limb showed a positive flow signal on the arterial spectrum under pressure. The internal diameter of the right subclavian artery was about 0.66 cm, the internal diameter of the right vertebral artery was about 0.43 cm, Vs 41 cm/s, Vd 17 cm/s, RI 0.59, with normal spectral pattern and positive flow signal. Diagnosis: left subclavian artery steal syndrome, left subclavian artery stenosis with atherosclerosis, left vertebral artery stenosis with blood reflux. After treatment with vasodilatation and anticoagulation, the symptoms improved, but the blood pressure on the left side was still 0, and the radial artery pulsation was weak. The subclavian artery steal syndrome, also known as vertebral artery-subclavian artery reflux syndrome, is caused by atherosclerosis or nonspecific inflammation of the subclavian artery or the unnamed artery, and in a few patients it can be caused by congenital subclavian artery stenosis and occlusion, aortic arch occlusion, thrombosis or trauma. The most common symptoms of this syndrome are vertigo, light paralysis, sensory abnormalities, bilateral visual impairment, diplopia, syncope, intermittent claudication, dysphonia, dysphagia, and intermittent upper limb weakness, pain, and intermittent upper limb limitation. A common sign is the absence of a pulse or a weakened radial artery in the affected upper limb, and in some patients a vascular murmur can be heard in the supraclavicular region. The diagnosis requires ultrasound Doppler examination or selective arteriography. The misdiagnosis of shock in this case was mainly due to the lack of awareness of the disease and failure to perform a comprehensive examination. It is recommended to routinely check bilateral blood pressure in patients with low blood pressure or shock, and to perform the necessary ancillary tests in suspicious cases to confirm the diagnosis as soon as possible. In addition to general treatment such as vasodilation and anticoagulation, carotid-subclavian artery bypass grafting or percutaneous transluminal balloon angioplasty (PTA) is feasible if available and has good results.