Cerebral Blood Flow and Internal Carotid Artery Flow During Carotid Surgery

In a series of 17 patients operated on for stenosis of the internal carotid artery, measurement of the blood flow in the internal carotid artery by a squarewave electromagnetic flowmeter was performed simultaneously with measurement of the regional cerebral blood flow (rCBF) by the 133Xenon injection technique. The measurements were made before and after endarterectomy. On completion of endarterectomy there was significant increase in mean internal carotid artery flow (ICAF), from 133 ml/min to 212 ml/min (P < 0.05), whereas mean rCBF remained unaltered. The ratio ICAF/rCBF gives brain substance in grams supplied by the internal carotid artery. The mean value of this ratio increased significantly from 231 gm to 452 gm after endarterectomy (P < 0.01). Thus cerebral hemodynamics tended to the normal postoperatively.