Carotid steal: report of ten cases.

The blood flow may be diverted from the external to the internal carotid artery via the carotid bulb in the absence of flow in the common carotid artery. We aimed to investigate the prevalence, hemodynamics, and clinical features of this condition. Reviewing the records of color duplex ultrasonographic examinations, we found carotid steal in 12 carotid arteries of 10 patients. In three patients flow in the ipsilateral external carotid artery was bidirectional. The steal had been demonstrated angiographically in six patients. The cause of the phenomenon was atherosclerosis, Takayasu arteritis, or trauma. Awareness of this pathway of collateral circulation may contribute to diagnostic work-up and expand management alternatives.