Subtle brain damage cannot be detected by measuring neuron-specific enolase and S-100 beta protein after carotid endarterectomy

Objective: To assess whether subtle brain damage after carotid endarterecto my could he detected using serum levels of neuron-specific enolase (NSE) or S-100 beta protein. Design: Prospective noninterventional study. Setting: University hospital. Participants: Twenty-two patients undergoing carotid endarterectomy and 16 patients undergoing repair of abdominal aortic aneurysm. Interventions: Serum levels of NSE and S-100 beta protein were measured in all patients before surgery and postoperatively at 12, 24, 36, and 48 hours . In patients undergoing carotid endarterectomy, neuropsychologic testing w as performed before surgery and postoperatively at discharge from the hospi tal and after 3 months using a neuropsychologic test battery. Measurements and Main Results: Compared with abdominal aortic surgery patie nts, the preoperative serum concentration of NSE was significantly higher i n carotid artery surgery patients. Postoperatively, the NSE serum level dec reased significantly after uncomplicated carotid artery surgery, and the le vel was then similar to that in the aortic surgery patients. Before operati on, the S-100 beta protein levels were similar in the two groups, but a sig nificant increase was seen in aortic surgery patients postoperatively. Neur opsychologic testing after uncomplicated carotid artery surgery revealed co gnitive dysfunction in 2 of 20 (10%) of the patients after 5 days and 3 of 16 (19%) of the patients after 3 months. There was no correlation between t he change in cognitive function and the changes in blood levels of either N SE or S-100 beta protein. Conclusions:Subtle brain damage after carotid artery surgery could not he d etected by measuring blood levels of NSE and S-100 beta protein. The NSE le vel was significantly higher before carotid artery surgery and decreased po stoperatively to the level observed in aortic surgery. Copyright (C) 2000 b y W.B. Saunders Company.