Due to the high degree of narrowing or occlusion of the subclavian artery or unnamed artery from the beginning of the vertebral artery to the proximal end, the blood flow from the vertebral artery or carotid artery on the healthy side flows through the subclavian artery on the affected side to the upper limb artery on the affected side with low blood pressure, thus causing the phenomenon of insufficient blood supply to the brain is called subclavian artery steal syndrome. This disease is relatively rare in clinical practice.
Four cases were admitted to our hospital in the past two years and are reported as follows:
I. Clinical data
Case 1: Male, 70 years old, with right upper limb weakness for more than 5 years. In the past 2 years, he had recurrent vertigo, sometimes black haze and fall after activity. There was no abnormality in cranial CT examination. Physical examination revealed that the right axillary artery, brachial artery and radial artery were not pulsating, and the right carotid artery was weakly pulsating. DSA examination showed that the right subclavian artery was occluded at the beginning, and the contrast medium flowed from the right vertebral artery into the right subclavian artery. The diagnosis was sclerotic occlusion of the right subclavian artery with blood-stealing syndrome.
After interventional treatment failed, axillary-axillary artery bypass grafting was performed with an 8 mm diameter PTFE artificial vessel with a support ring. After the operation, the pulsation of the right radial artery was restored and the vertigo symptoms disappeared. He was discharged from the hospital on warfarin 2.5 mg/day. The symptoms did not appear in six months of follow-up.
Case 2: Female, 36 years old, diagnosed as head and arm type aortitis in our hospital ten years ago due to symptoms of dizziness and blurred vision, and given hormone treatment. In the past year, the symptoms gradually worsened, sometimes black haze and fall down. DSA examination showed that the left subclavian artery was occluded from the beginning, there was long segmental stenosis in both carotid arteries, and there was regurgitation in the left vertebral artery.
Axillary-axillary artery bypass grafting was performed with an 8 mm diameter PTFE artificial vessel with a support ring. Three months later, due to the increase of warfarin dose, he had bleeding during menstruation, but the bleeding stopped after stopping the drug. After that, he was admitted to our hospital because of viral encephalitis contracted by high dose of hormone, and was examined by transcranial ultrasound.
Case 3: Male, 55 years old, had dizziness and blurred vision three years ago. He had a history of hypertension and cerebral infarction. On physical examination at admission, a vascular murmur could be heard in the left neck, and the left radial artery pulsation was diminished. DSA showed no abnormality in the right subclavian artery and the right common carotid artery, stenosis at the beginning of the left subclavian artery and reversed flow in the left vertebral artery.
The diagnosis was sclerotic stenosis of the left subclavian artery and right subclavian artery steal syndrome. A stent was placed with the Seldinger technique through the stenosis of the left subclavian artery, and after balloon dilation. After surgery, the left radial artery pulsation returned to normal. The symptoms of dizziness and blurred vision disappeared. At one year follow-up, the symptoms did not recur and the radial artery pulsation was strong.
Case 4: Female, 49 years old, presented with headache and blurred vision 6 months ago, which improved when lying down. Physical examination revealed weak pulsation of the left radial artery and weak pulsation of the right dorsalis pedis and posterior tibial artery. Ultrasonography showed that the left vertebral artery was reversed and the flow velocity of the left radial artery was significantly reduced. DSA showed that the left subclavian artery was occluded, the left vertebral artery was reversed, the right renal artery was occluded, and the right superficial femoral artery was partially occluded.
We diagnosed mixed aortitis. Considering that the patient did not have hypertension and intermittent claudication was not obvious, the right renal artery and right superficial femoral artery did not need treatment for the time being. Axillary-axillary artery bypass grafting was performed with an 8 mm diameter PTFE artificial vessel with a support ring. After the operation, the pulsation of the left radial artery was restored, and the headache and blurred vision disappeared. He was discharged from the hospital on warfarin 2.5 mg/day.
II Discussion
There are many causes of subclavian artery stenosis or occlusion, mainly atherosclerosis, but also aortitis, congenital vascular malformation, trauma, mediastinal tumor or inflammation. Among the patients we treated, 2 cases were arteriosclerosis and 2 cases were aortitis. The diagnosis of blood-stealing syndrome is not difficult to make because of the typical clinical symptoms of cerebral ischemia and the signs of no arterial pulsation in one upper limb.
If there is severe stenosis or occlusion of the proximal subclavian artery or the unnamed artery, the diagnosis can be confirmed by prolonging the photographic time and finding the regurgitation of the vertebral artery or the internal carotid artery, which provides the basis for the choice of surgery.
Treatment of the steal syndrome is aimed at restoring paracrine flow in the vertebral or carotid arteries to address the hypoperfusion of brain tissue and the resulting symptoms. Only surgical or interventional treatment can achieve the therapeutic goal. In the case of theft syndrome due to head and brachial aortitis, it is best to choose surgery in the stable phase to reduce the recurrence rate after surgery. Interventional treatment has developed rapidly in recent years, and nowadays, for patients with stenosis of the subclavian artery or the unnamed artery, percutaneous transfemoral subclavian and unnamed artery angioplasty (PTA) is mostly chosen.
This method has the advantages of minimal injury, simple operation and does not affect reoperation after recurrence. However, its long-term patency rate is lower than that of bypass surgery, and the success rate of interventional angioplasty in patients with occlusion is very low, and there is a risk of penetrating the vessel, so PTA should be avoided in patients with occlusion, and there was one case of subclavian artery stenosis in our group in which PTA was successfully performed with satisfactory postoperative results. However, one case failed because the guidewire could not pass through the occlusion.
There are many surgical treatment methods for blood steal syndrome, mainly carotid-subclavian artery bypass, transthoracic unnamed artery or subclavian artery endarterectomy, axillary-axillary artery bypass, etc. Transthoracic endarterectomy of the unnamed artery or subclavian artery is rarely used because of the high surgical trauma and mortality rate. Carotid-subclavian artery bypass grafting is performed with an artificial vessel between the patent carotid artery and the occluded distal subclavian artery, and some data suggest that the patency rate of the artificial vessel bypassed here is significantly higher than that of the saphenous vein.
This procedure requires no stenosis of the carotid artery, otherwise carotid steal will occur, so it must be clearly understood during preoperative imaging. This procedure also requires skilled operation to minimize the blocking time of the carotid artery to avoid cerebral ischemic injury. Axillary-axillary artery bypass surgery is relatively simple and does not require blocking the carotid artery, so it is safer and more commonly used in clinical practice.
The disadvantage of this procedure is that the artificial vessel is long and crosses the sternum, so it is necessary to use an artificial vessel with a support ring to avoid deformation and stenosis of the artificial vessel after compression. The three cases operated in this group were all performed by axillary-axillary artery bypass grafting, and the recent results were good after 3 months and 1 year of follow-up.
Postoperative anticoagulation should not be neglected in either interventional or surgical procedures. It directly affects the long-term outcome of patients. Since low molecular heparin not only can anticoagulate but also has the effect of inhibiting intimal hyperplasia, in order to prevent postoperative thrombosis or excessive intimal hyperplasia in the artificial vessel as well as the original arterial stenosis, we gave low molecular heparin 0.4 ml subcutaneously every 12 hours for 1-2 weeks after surgery.
The patient was discharged from the hospital and switched to oral warfarin or poliovir for 6 months, with the first dose of warfarin at 5 mg and 2.5 mg daily thereafter. it is important to check the coagulation picture regularly during the use of warfarin to avoid bleeding from other sites. In our group, there was one case of heavy bleeding during menstruation due to self-increased warfarin dose and failure to regularly check coagulation picture (PT, PT-INR). Poliovel is relatively safe in use but expensive. The clinical decision should be made on a patient-by-patient basis.