Effects of treatment with the calcium-entry blocker nimodipine on the cerebral blood flow (SPECT) and blood viscosity of patients affected by cerebral chronic vascular insufficiency

Abstract

Nimodipine is a calcium-antagonist agent capable of acting specifically on brain circulation. The aim of this clinical study was to evaluate possible changes of brain perfusion and blood viscosity in 11 patients with chronic and clinically stable cerebral ischemia after long-term treatment with the oral administration of nimodipine (30 mg 3 times daily for three months). Blood flow in the brain was measured using a Single-Photon-Emission Computed Tomography (SPECT) after the intravenous administration of the tracer 925 Mbq of HM–PAO–Tc99m. Four transaxial slices were chosen: one cerebellar and three supratentorial slices at 4, 5.6 and 7.2 cm above the orbito-meatalline. The scintigraphic images, obtained before and after the treatment, are compared both qualitatively and quantitatively, using the Index of Cortical Perfusion ( ICP). Blood viscosity was also evaluated (shear rate 90 s⁻¹ and 30 s⁻¹) at the same time. After a three month treatment, the scintigraphic images showed an improvement of cerebral blood flow in 9 patients while the mean values of ICP of 11 cases were increased statistically in 13 of the 18 tested regions. A statistically significant reduction of blood viscosity was also observed. This favourable effect of nimodipine in chronic cerebral ischemia can be attribute to its calcium-blocker entry effect, mainly acting on blood, vessels and brain tissue.