HYPERPERFUSION POST-ENDARTERECTOMY

We performed serial transcranial Doppler examinations on 35 patients u ndergoing 40 consecutive carotid endarterectomies (CEAs) to study alte rations in collateral flow and middle cerebral artery (MCA) blood flow velocity. Ipsilateral peri-orbital collateral flow was abolished abru ptly in all 16 cases. Compensatory anterior communicating artery colla teral was abolished in 17 of 18 cases, and reversed in the other with a remaining severe contralateral carotid lesion. Post-operatively, ips ilateral MCA velocity increased significantly in 26 cases, decreased i n 7, and remained unchanged in 7. Sixteen patients had transient hyper perfusion during the first week. Similar changes were observed on the contralateral side. There was no significant association between hyper perfusion and clinical or physiological variables except age. One pati ent had ipsilateral headache post-operatively associated with hyperper fusion. We conclude that CEA produces rapid alterations of collateral flow and may affect blood flow to both cerebral hemispheres. Transient hyperperfusion, although common, is seldom severe and rarely symptoma tic.