External carotid occlusion as a cause of recurrent ischemia after carotid endarterectomy.

Our experiences with a patient who developed recurrent hemispheric transient ischemic attacks 3 1/2 years after ipsilateral carotid endarterectomy are described. Although repeat arteriography demonstrated smooth and unobstructed common and internal carotid arteries and a normal intracranial circulation, there was complete occlusion of the external carotid artery at its origin, which appeared as a stump or diverticulum at the origin of the internal carotid artery. This stump was filled with atherothrombotic debris and served as a source of emboli to the adjacent and patent internal carotid artery. Excision of the stump effected complete relief of the recurrent ischemic symptoms. The pernicious potential of an external carotid obstruction when adjacent to a patent internal carotid artery should be recognized. To prevent this avoidable complication of carotid endarterectomy, we recommend that the origin of the external carotid artery be treated with the same standards of technical perfection as those customarily applied to the internal and common carotid arteries during this procedure.