Effect of carotid endarterectomy on cerebral blood flow and its response to hypercapnia

Cerebral blood flow (CBF) was measured in 14 patients before carotid endarterectomy, 3 h after surgery and 2 days postoperatively using the intravenous xenon-133 technique. In 11 of the patients CBF was remeasured at 6 months and in 8 patients CBF and the response to hypercapnia (5 per cent CO2 in air) was measured pre-operatively and 6 months following surgery. All operations were performed using an intraluminal Javid shunt and internal carotid artery (ICA) 'stump' pressure was recorded. CBF measured at 3 h after endarterectomy revealed a postoperative cerebral hyperperfusion with significantly increased flows in both hemispheres. There was a significant correlation between carotid cross clamping time and ipsilateral hemispheric CBF increase which implied an ischaemic aetiology for the hyperperfusion and supported the routine use of an intraluminal shunt in carotid endarterectomy. Six months after surgery, CBF had returned to its preoperative value but reactivity to CO2 was significantly improved, which suggested that the operation had increased cerebral reserve.