Noninvasive Testing of Dynamic Component of Internal Carotid Artery Stenosis in Patients with Chronic Cerebrovascular Disease

Abstract

By means of Doppler spectral analysis it was shown that internal carotid artery stenosis has a dynamic component that determines the possibility of changes in the area of stenosis under various influences. It was found that the cold pressor test may increase the area of stenosis in some patients for up to three to five hours. In such cases reduction of blood flow volume in the common carotid artery and decrease of cerebral blood flow in the ipsilateral hemisphere of the stenosis are observed. Such a response was effectively removed by nifedi pine. At the same time nifedipine itself is capable of changing the area of steno sis, either enlarging or reducing it. In the first case enhancement of brain blood supply is observed, and in the second case, its decrease. The data obtained disclose one of the reasons for the variability in therapeutic effects of vasodila tors in patients with cerebrovascular disorders.