Cerebral blood flow and cerebrovascular reserve 5 years after EC-IC bypass

CBF-studies using the Xenon-133-inhalation technique were performed in 18 patients with a unilateral carotid artery occlusion, 5.4 years after a STA-MCA procedure. For comparison we used the CBF data of 29 patients with the same diseases who had had conservative treatment for a variable period of time. CBF was measured during rest and after the intravenous administration of 1 g acetazolamide. During rest we found a significant interhemispheric difference in both groups. After activation with acetazolamide this difference disappeared in the bypass group, but not in the conservatively treated patients. Our data show that the bypass procedure obviously affects the vascular reserve capacity in a positive way over a long period of time. One criteria for success of STA-MCA procedures might be the cerebral reserve capacity tested with CBF-studies under activation.