Chronic brainstem ischemia in subclavian steal syndrome.

Subclavian steal syndrome is usually an incidental finding and rarely causes vertebrobasilar ischemia. We present a 58-year-old man who, over six months, experienced progressive slowing in both talking and walking. Cervical duplex sonography revealed severe stenosis of the right subclavian artery; fixed retrograde flow was noted in the right vertebral artery on transcranial Doppler. The hyperemia-ischemia cuff test resulted in considerable reduction in flow velocities in both posterior cerebral arteries. We attributed his slowness to chronic vertebrobasilar ischemia and surgical revascularization was performed. His symptoms subsided immediately after surgery. The improved perfusion in the posterior circulation was demonstrated on technetium-99 hexamethylpropyleneamine oxime single photon-emission CT. Early diagnosis and prompt treatment resulted in an improved quality of life.