Endarterectomy for narrowing of the external carotid artery in a patient who underwent extracranial-intracranial bypass for occlusion of the internal carotid artery--case report.

A 56-year-old man had undergone extracranial-intracranial (EC-IC) bypass surgery for occlusion of the right internal carotid artery. Six years later, he complained of transient episodes of numbness in the left arm, occurring periodically over the previous 3 months. Neuroimaging showed the right external carotid artery was severely narrowed and cerebral blood flow (CBF) was diffusely low. Endarterectomy of the right external carotid artery was performed. Postoperative CBF was markedly improved, suggesting that EC-IC bypass became effective again by endarterectomy of a parent artery.