2020 Volume 69 Issue 2 Pages 267-273
We here report a case of left subclavian artery stenosis in which the subclavian artery steal phenomenon was not detected owing to the anomalous origin of the left vertebral artery. A man in his seventies complained of numbness on the left side of his body and visited our hospital. He was diagnosed as having cerebral infarction by head CT and MRI, and he underwent carotid ultrasonography to find its cause. There were no findings that indicated an occlusion or stenosis of the right and left carotid arteries, and the blood flow in the vertebral arteries did not regurgitate. The next day, we performed 3DCTA and found left subclavian artery stenosis. In addition, the left vertebral artery was branched directly from the aortic arch. We performed carotid ultrasonography again and observed the left subclavian artery. A mosaic signal was observed on the central side of the artery, and the maximum flow velocity exceeded 4 m/s. Usually, if there is a more-than-moderate stenosis on the central side of the subclavian artery, the subclavian artery steal phenomenon can be detected. However, in this case, the blood flow of the left vertebral arteries did not regurgitate because of an anomalous origin. In this case, we were able to prevent oversight by auscultation and comparing between the right and left upper limb blood pressures before the examinations.
