Effects of PTA/stent on subclavian steal syndrome: Evaluation of cerebral blood flow using SPECT

Abstract

[Purpose] We evaluated cerebral circulatory dynamics in cases of subclavian artery stenosis or occlusion using dual-table autoradiography (ARG) to investigate the characteristics of cerebral circulatory dynamics of subclavian steal syndrome. [Subjects and methods] The study population consisted of 9 cases of subclavian steal syndrome (2 cases of subclavian artery stenosis, 5 cases of subclavian artery occlusion, 2 cases of brachiocephalic artery stenosis) treated by percutaneous transluminal arterial angioplasty and stenting (PTA/stent) at our department in the 3~ year period from April 2006. In all cases, quantitative determination of cerebral blood flow was performed using 123I - labeled N-isopropyl-P-iodoamphetamine (123MMP) before and after PTA/stent. Quantitative determination of cerebral blood flow was performed using dual-table ARG, which consecutively measures the amounts of cerebral blood flow at rest and during acetazolamide loading. Stereotactic extraction estimation analysis (SEE) was used for statistical image analysis on cerebral blood flow single-photon emission computed tomography (SPECT), and the amounts of cerebral blood flow at rest and cerebral perfusion reserve, both from the region of interest, were calculated. [Results] PTA/stent was successful in all cases, with subclavian steal phenomenon resolved, and the symptoms improved in all cases. In cerebral blood flow evaluation, the amount of cerebral blood flow at rest before treatment (mL/100 g/min) was 34.5 + 5.4 in the cerebral hemisphere, and 36.8 + 4.3 in the cerebellar hemisphere; cerebral blood flow reserve (%) was 40.8%+18.4% in the cerebrum and 26.9% +21.8% in the cerebellum. After the treatment, cerebral blood flow at rest in the cerebellum was 37.2 + 5.5 mL/100 g/min and did not change from revascularization achieved by PTA/stent. However, a significant improvement was observed in cerebral blood flow reserve, which was 36.4% + 19.2%. [Conclusion] Subclavian steal syndrome can be evaluated using 123I-IMP SPECT dual-table ARG, and the results can be understood as decreases in cerebral blood flow reserve in the cerebellum. The cerebral circulation in the vertebral-basilar system appeared to have been improved through revascularization achieved by PTA/ stent, causing improvement in the symptoms. 123I~IMP SPECT dual-table ARG may be a useful index in determining the treatment. © 2011 by The Japanese Congress of Neurological Surgeons.