Regional cerebral blood flow in patients with internal carotid artery stenosis: Effects of nifedipine and nimodipine

Regional cerebral blood flow (rCBF) in 87 patients with CBF decreased due to unilateral stenosis of internal carotid artery was studied by using the¹³³xenon infusion technique and a 30-detector setup. On the side of stenosis a decrease in the mean hemispheric blood flow (rCBFh) with an elevated deviation of rCBF from rCBFh was observed. Administration of a single oral dose of either nifedipine or nimodipine induced various changes in rCBF. A classification of their effects with due regard for changes in both the mean value of the hemispheric blood flow and the flow distribution is described. The decrease in both the interhemispheric difference of rCBFh and the deviation of rCBF from the hemispheric mean flow accompanying the increase of the total brain blood flow was considered as being the most beneficial drug effect. This positive reaction was found more frequently when nimodipine was used. In some patients nifedipine, and in fewer, nimodipine, induced nonbeneficial changes in rCBF with elevation of the interhemispheric difference and an increase in the number of ischemic and hyperemic regions on the side of stenosis. The types of drug effects after administration of a single dose were similar to those after two weeks of monotherapy. It is supported that this approach allows assessment of cerebral hemodynamics and drug effectiveness in cerebrovascular disorders.