Cerebral blood flow and common carotid flow in neurologically asymptomatic carotid endarterectomy patients

To define subgroups in 50 neurologically asymptomatic patients with carotid stenosis (mean diam. of stenosis 81.1 +/- 12.5%) regional cerebral blood flow (rCBF) and common carotid artery flow were measured by means of the intravenous Xenon-133 technique and a Doppler flowmeter, respectively. The rCBF studies were performed both at rest and after administration of acetazolamide (Diamox). In this asymptomatic cohort of 50 patients we found subgroups with significant hemispheric baseline asymmetry (BA) (five patients; BA = 7.2 +/- 1.8%) and/or pathological Diamox asymmetry enhancement (DAE) (five patients; DAE = 8.8 +/- 1.3%). Carotid endarterectomy in these cases resulted in a significant reduction of hemispheric differences of rCBF (postoperative BA = 0.4 +/- 3.4, postoperative DAE = 1.7 +/- 3.8). Measurements of common carotid flow revealed significantly higher flow rates in the postoperative period and compensation of intercarotid flow asymmetry. In pathophysiologically defined preclinical subgroups of cerebrovascular disease with hemispheric rCBF differences and/or impairment of the cerebral vascular reserve capacity surgical procedures might be useful.