Ultrasonic Diagnosis And Clinic Of Subclavian Steal Syndrome

Disease of subclavian artery occlusion has been found over one hundred years. Because more than 2/3 patients with subclavian artery stenosis showed no syndrome and it needed DSA to confirm, SSS was once thought as a kind of rare disease. However, as the development of ultrasonics and imageology, more and more patients get an earlier diagnosis and treatment. How to choose a suitable method to diagnose SSS is very important. We should adopt individual therapy to improve the patients'prognosis. The above mentioned have considerable clinical meanings.This study collected 107 patients who had undergone ultrasonography. We used TCD to check the direction, velocity of flow, the pulsatility index and spectrum of MCA, ACA, PCA, VA, BA and ICA; we used carotid sonography to check the thickness of inner membrane, the inside diameter of vessel, the velocity and direction of flow and the spectrum of CCA, ICA, ECA, VA and SUBA. Then we analyzed the results.The results are as follows. According to the direction of ipsilateral VA, the subclavian steal phenomenon is divided into three stages: stageâ… (deceleration in systole), stageâ…¡(alteration flow with reversed flow in systole and normal flow in diastole) and stageâ…¢(reversed flow completely). The steal pathway is defined as basilar artery steal pathway (with steal waveform in basilar artery) or non-basilar artery steal pathway (normal direction in basilar artery). All of the 92 patients are of single affection. The difference of PSV in the contralateral VA among the three groups has significant meaning (P=0.0002). The PI of ipsilateral VA of 70 patients is different with that of MCA (P<0.01). According to TCD, 44 patients(47.8%) are of steal stageâ… , 34 patients(37.0%) are of steal stageâ…¡, and 14 patients(15.2%) are of steal stageâ…¢. Among the 44 patients, according to the carotid sonography there are 36 patients with moderate stenosis vessels, 8 patients with medium stenosis vessels; among the 34 patients, according to the carotid sonography there are 5 patients with moderate stenosis vessels, 16 patients with medium stenosis vessels, 13 patients with severe stenosis vessels; among the 14 patients, according to the carotid sonography there are 14 patients with severe stenosis vessels or obliteration. The steal stage correlates well with the stenosis of subclavian artery(r=0.8). Among the 44 patients that are of steal stageâ… according to TCD, there are 3 patients of inapparent steal and 41 patients of steal stageâ… according to the carotid sonography; among the 34 patients that are of steal stageâ…¡according to TCD, there are 11 patients of steal stageâ… , 13 patients of steal stageâ…¡and 10 patients of steal stageâ…¢according to the carotid sonography; among the 14 patients that are of steal stageâ…¢according to TCD, the carotid sonography also shows steal stageâ…¢. To some patients, the steal stage of TCD and carotid sonography can have a difference. Among the 92 patients, 50 patients(54.3%) have symptoms with VBI, 27 patients(29.3%) with ischemic symptom on ipsilateral arm and 15 patients(16.3%) with both. There is no significant association between the VBI and the severity of steal phenomenon(P>0.05). Only 2 patients have basilar artery steal pathway.From this study, we can draw the conclusions as follows: TCD has the advantages of cheapness, direct-viewing, shortcut and exactitude to diagnosis SSS, and combined with carotid sonography we can identify the etiopathogenisis, diseased region and degree. The steal phenomenon is more serious, the PSV is higher. Once we find pulsatility index(PI)of vertebral artery is higher than that of the internal carotid artery system ,we should pay more attention to see if there exists subclavian steal phenomenon. The steal stage correlates well with the stenosis of subclavian artery(r=0.8). And there is difference between the results of TCD and carotid sonography. The VBI is not associated with the degree of steal phenomenon.Through the study, we should choose ultrasound as the primary method in screening of SSS. If the patients need exact fixing and interventional therapy, they should choose DSA examination. After interventional therapy, ultrasound can be used as a method of follow-up visit and rechecking.However, to check the vessels with ultrasound, especially the intracranial arteries, the accuracy also depends on the knowledge, experience and technical level of the operator. It also needs the ability of analyzing the character of diseases and the change of haemodynamics, then we can make a correct conclusion.