Steal phenomenon at unclamping during carotid endarterectomy.

A patient is reported who during vigorous back bleeding after unclamping of the internal carotid artery during endarterectomy had EEG slowing and a postoperative increase in neurological deficit. This phenomenon, an apparent steal, has not been reported and suggests that EEG monitoring is as vital at unclamping as it is after clamping. The patient also raises questions about the risk of early endarterectomy for those who have persistent deficits, even with unobstructed vessels.