Case report: a variant of the subclavian steal syndrome. Demonstration by duplex Doppler imaging.

The subclavian steal syndrome results from occlusion of the proximal subclavian or innominate artery which causes reversal of blood flow in the ipsilateral vertebral artery. We describe a case where a further occlusion of the ipsilateral common carotid artery (CCA) resulted in an intermittent reversal of flow in the ipsilateral external carotid artery (ECA), to siphon blood up the internal carotid artery (ICA) and down the ipsilateral vertebral artery.