1. What is pulselessness? What is the cause? ”Pulselessness is an immune disorder, the cause of which is not fully understood, and is usually seen in the narrowing or occlusion of the subclavian artery. Elderly people with long-term systemic diseases, including hypertension, diabetes, and coronary heart disease, are also prone to similar pulselessness, but the cause is mainly atherosclerosis. The reason why “pulselessness” is rare is that it is particularly easy to be misdiagnosed, and most patients with dizziness and headache think it is caused by cervical spondylosis. Therefore, Prof. Wang Zhi reminds all patients that if they find a localized weakened pulse or even “no pulse”, they should first consider the possibility of having “pulselessness”. 2.Why do I feel dizzy when I lift my hand? Prof. Wang Zhi said that the subclavian artery is a very important blood vessel that supplies blood to the upper limbs and part of the brain. If there is occlusion or narrowing at its starting point, when the upper limbs move excessively, the upper limbs will “steal” the blood supplied to the brain by the vertebral artery, and the blood will flow backwards from top to bottom, and the brain will become ischemic, resulting in vertigo, nausea, vomiting This can lead to vertigo, nausea, vomiting, transient loss of consciousness, blurred vision, and other symptoms. Insufficient blood supply to the upper extremities may also occur, manifesting as weakness, abnormal sensation, chills, weakened pulse, pale skin or no pulse syndrome, and significantly lower blood pressure on the affected side compared to the healthy side or can not be measured. 3.What are the risks of blood theft? Blood theft will initially lead to cerebral blood supply insufficiency, but it will recover within minutes or hours. If the narrowing is more severe, irreversible brain cell necrosis will occur, with serious consequences, and even sudden death. 4.How to prevent and treat? The occlusion or stenosis of the subclavian artery is generally more common on the left side. When measuring blood pressure, the blood pressure of both upper limbs should be measured. If the difference in blood pressure between the two sides exceeds 20~25mmHg, it should be highly alert. If the pulse is not the same, and one arm has no pulse or one side is weaker than the other, prompt examination should be conducted to consider whether the subclavian artery steal blood syndrome is present. The most common cause of subclavian artery piracy syndrome is atherosclerosis, so it is recommended to take lipid-lowering and anti-platelet drugs and to review them regularly. Interventional (stent) treatment is preferred for patients who have developed symptoms of subclavian artery piracy syndrome (stenosis or blockage exceeding 75%), or surgical (endovascular debridement or bypass) treatment for patients who have already occluded and cannot be opened.