Imaging diagnosis of subclavian steal syndrome secondary to takayasu arteritis affecting a left-side subclavian artery

Takayasu arteritis (TA) is a rare form of large-vessel, chronic, occlusive vasculitis. It involves mainly aorta and its main branches, causing stenosis and/or obstruction. Its frequency has been estimated at 2.9 cases per 1 million people. Epidemiologically, it is found principally in young female patients and is more prevalent in Asia and Latin America. When there is severe stenosis or occlusion in subclavian artery, the phenomenon of subclavian steal syndrome (SSS) occurs, which usually causes symptoms of the vertebrobasilar territory because blood supply to the arm is sustained by reversal of flow in ipsilateral vertebral artery. We describe a case of SSS thought to be due to TA in a Mexican woman. Doppler ultrasound of neck vessels showed retrograde flow in left vertebral artery during systole. Digital subtraction angiography confirmed 30% stenosis of left subclavian artery with filling of left vertebral artery in retrograde direction. In presenting this case, we carried out a brief review of TA, main features in imaging diagnosis of SSS, and the infrequently reported association of TA with SSS.