The TCD And Clinical Observation Of Subclavian Steal Syndrome

Objective:To observe transcranial Doppler changes in patients with subclavian steal syndrome(SSS), and analyse its hemodynamic cause and mechanism; investigate the clinical features, imaging findings and risk factors in SSS patients.Methods:60clinically-diagnosed SSS, bilateral subclavian artery stenosis patients but associated with cardiogenic emboli were excluded. All the patients underwent magnetic resonance angiography (MRA) or computed tomography angiography (CTA).40patients underwent digital subtraction angiography. The gender, age, comorbidities including hypertension, diabetes, coronary heart disease and hyperlipidemia of all the patients were observed and recorded as well as their history of smoking and drinkingAccording to the vessel inspection results SSS patients were divided into subclavian artery stenosis and stenosis at the origin of vertebral artery. According to the stenosis degree SSS were also divided into mild, moderate, severe stenosis and blood vessel occlusion.46cases of transcranial doppler and carotid artery ultrasound examination results kept complete.lesions of the lateral vertebral artery steal and extent of lesions of the lateral subclavian artery stenosis were recorded. The risk factors, clinical symptoms and signs in two groups of SSS patients were compared, and the relationship of stenosis degree and steal extent were analysed. The difference of double upper extremity blood pressure in selected patients were investigated. The data were processed using SPSS15.0statistical software.Results:Subclavian artery stenosis was43cases. The initiation part of vertebral artery stenosis was6cases. Subclavian artery accompanied with ipsilateral vertebral artery stenosis was9cases. No vascular stenosis was2cases. The mean age of SSS patients was64.2years. The risk factors for SSS included hypertension, diabetes and dyslipidemia.52patients developing subclavian artery stenosis incuded12mild,25moderate,13serious and2occlusion cases.30cases in steal I stage,24cases in Ⅱ and6cases in III. The double arm blood pressure difference were7.43±4.12,27.79±10.19and39.17±8.30mmHg respectively in3groups of patients with different steal degree by TCD.Conclusion:1.The main characteristic of SSS was posterior cerebral circulation ischemia clinically. Among the60patients, the patients with lesions of the lateral supraclavicular fossa bruit accounted for37.21%, prompting that the attention should be paid to examine vascular murmur auscultation in clinic.2. The TCD examination revealed right subclavian artery steal blood was sometimes more sensitive than DSA, which also should raise clinical attention.3. TCD changes of vertebral artery with a steal spectrum was due to former vertebral artery stenosis or complete occlusion at the proximal end of side subclavian or innominate artery in large part and in a small part to origin stenosis of ipsilateral vertebral artery. The reason of this phenomenon is pressure drop at ipsilateral vertebral artery distal, which is lower than the pressure at contralateral vertebral artery or Willis artery, and TCD only certifcates there is no blood-supply to subclavian artery with a same pprinciple with SSS.4. The patients with vertebral artery stenosis whose steal degree does not reached the stage Ⅲ, can have the symptom of posterior circulation ischemia, namely posterior circulation ischemia is more susceptible to the patients with vertebral artery stenosis than those with subclavian artery stenosis.5. The high probabilities of complication in SSS patients are hypertension, dyslipidemia and diabetes.6. part of the SSS patients has a more-than-20mmHg difference between double upper extremity blood pressures, moreover the difference becomes more obvious as the steal level increases.7. The degree of subclavian artery or vertebral artery stenosis positively correlated with the steal and stenosis degree detected by Doppler.