The blood pressure in the two arms is inconsistent, it may be that the blood has been "stolen"

Author: Liu Yumei, Chief Physician, Xuanwu Hospital, Capital Medical University

Reviewer: Chief Physician of Huayang Capital Medical University Xuanwu Hospital

Have you ever experienced dizziness, blurred vision or double vision, black spots in front of your eyes, unsteady walking, etc. when lifting heavy objects with both hands? If you measure your blood pressure at this time, you will find that the blood pressure in your two arms is different. If you encounter this situation, you must be careful, as it may be subclavian artery steal syndrome. At this time, you must go to the hospital for examination in time.

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1. Why are the blood pressures of the two arms different?

The blood pressure in the two arms of a normal person may not be completely consistent, which may be related to factors such as measurement posture, measurement error and congenital vascular variation. Under normal circumstances, the blood pressure on the left side will be 5 to 10 mmHg higher than that on the right side, so if the difference in blood pressure between the two arms is less than 20 mmHg, it is normal.

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However, if the difference in systolic blood pressure between the two arms exceeds 20 mmHg after multiple measurements, it indicates that there is stenosis or occlusion in the blood supply artery (subclavian artery, axillary artery and/or brachial artery) of the arm with lower blood pressure. If this happens, the blood pressure should be based on the relatively higher side. Patients are advised to go to relevant hospitals for upper limb and neck vascular ultrasound examinations to find the stenosis, clarify the nature of the vascular lesions, and treat them early.

If the blood flow in the two arms is asymmetrical, the side with lower blood pressure may "steal" blood to meet the body's needs when grasping heavy objects, and the patient may experience ischemic symptoms such as dizziness and blurred vision. This is a manifestation of subclavian steal syndrome.

What is subclavian steal syndrome?

Simply put, subclavian steal syndrome is when the arm "steals" blood from the head, resulting in insufficient blood supply to the head.

Under normal circumstances, the subclavian artery is responsible for supplying blood to the artery of the arm on the same side, and at the same time participates in the blood supply of the posterior circulation arteries of the brain through its branch vertebral artery. When one side of the subclavian artery is severely narrowed or occluded, the blood supply to the arm on the same side will be affected, so some patients will experience low blood pressure or loss of pulse in the affected arm, and due to reduced blood flow, the affected side will experience weakness and numbness.

When the patient uses the arm on the side with lowered blood pressure to perform activities such as grasping heavy objects, the arm needs more blood flow. However, the blood flow in the narrowed or occluded blood vessels cannot meet the demand after the activity, so it has to "steal" blood from the head and "steal blood" from the intracranial or contralateral subclavian artery through the vertebral artery to meet the blood supply needs of the affected arm, thereby causing cerebral ischemia. At this time, the patient may experience dizziness, double or blurred vision, black spots in front of the eyes, unsteady walking and other symptoms of ischemia of the posterior circulation arteries in the cranial artery. This is subclavian steal syndrome.

Severe patients may lose consciousness due to cerebral ischemia, leading to sudden falls and other accidents. Therefore, if you feel dizzy when shaking your hands or holding heavy objects, you must stop the activity immediately and sit down or lie down slowly to allow blood to flow back to the head.

In addition, relevant examinations of the arm and neck blood vessels should be carried out as early as possible. Neck vascular ultrasound, head and neck computed tomography vascular imaging, etc. can be used to determine whether the subclavian artery is narrowed or occluded, so that symptomatic treatment can be given.

How to treat subclavian steal syndrome

1. Choose the right treatment

There are two ways to treat subclavian steal syndrome: medical treatment and surgical treatment. Which method to use should be selected based on the patient's actual situation.

Medical treatment is mainly to expand the volume and maintain appropriate blood pressure to ensure normal cerebral blood perfusion, while anti-platelet aggregation, blood lipid regulation and other treatments are also carried out. Elderly patients with steal syndrome caused by atherosclerosis can take medical treatment and take anticoagulant or antiplatelet aggregation drugs to reduce the formation and development of thrombus.

Patients with subclavian artery occlusion or stenosis need surgical treatment, such as balloon angioplasty, intravascular stenting, carotid endarterectomy, internal and external carotid artery bypass grafting, and other revascularization methods to improve cerebral blood perfusion.

After medical or surgical treatment, the severity and frequency of limb tremors in most patients can be reduced or even completely relieved.

2. Provide good daily care

In addition to the above-mentioned routine treatments, patients with subclavian steal syndrome also need to pay attention to daily care, make adjustments in diet, lifestyle habits, etc., avoid risk factors, facilitate disease recovery, and achieve better prognosis.

First of all, the diet should be light, mainly consisting of easily digestible and nutritious foods such as eggs, milk, lean meat porridge, tofu, etc. You should also eat more fruits and vegetables to supplement vitamins, and avoid greasy, raw, cold, spicy, high-fat, and high-calorie foods.

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Secondly, try to move as little as possible within 24 hours after surgery to avoid bleeding and twisting of the artificial blood vessel. Avoid strenuous neck exercise within two weeks to facilitate the growth of the vascular endothelium.

Again, pay attention to your lifestyle, maintain a regular life, avoid fatigue and staying up late, quit drinking and smoking, and ensure adequate rest to facilitate physical recovery.

Finally, pay attention to emotional management and adjust negative emotions such as anxiety and fear in a timely manner. If necessary, seek psychological treatment to alleviate anxiety symptoms.

There is no effective way to prevent subclavian steal syndrome. Patients can maintain a light diet, quit smoking and drinking in their daily lives. If unexplained dizziness, fainting and other symptoms occur, accompanied by upper limb ischemic symptoms, the blood pressure of both arms can be measured. If the blood pressure difference is more than 20 mmHg, you should go to the hospital for treatment in time.

References

[1] Zhao Xiaoxi, Ma Xin. A case of transient ischemic attack with limb shaking combined with subclavian artery steal syndrome and literature review[J]. Chinese Journal of Cerebrovascular Diseases, 2021, 18(11): 790-793.