The Influence of Carotid Stenosis on Cortex Perfusion

Abstract

Regional cerebral cortex perfusion (CPR) rates were measured in 34 patients who were being considered for extracranial vascular surgery in the Professorial Surgical Unit at St. Mary’s Hospital, London. 10 patients eventually had an operation and the measurements were then repeated postoperatively. The cerebral blood flow data were not used in the selection of patients for surgery. Simultaneous bilateral measurements of regional cerebral cortex perfusion rates were estimated by the inhalation method. This technique is particularly suitable for the study of the effect of carotid lesions on cortex perfusion rates and has some advantages over other methods of blood flow measurement currently available. First it gives simultaneous bilateral measurements, and in the present series this has shown to give valuable additional information, secondly all sources of blood supply to the hemisphere are labelled with tracer, third no carotid puncture or internal carotid artery catheterization is necessary. This is particularly useful for carrying out postoperative measurements after the acute effect of the operation has passed and where there is no indication for repeat angiography. In addition the response to the inhalation of 5% CO2 was measured in 10 patients, in 4 of these the measurements were repeated postoperatively. The lesions were divided into 4 grades according to the single-plane angiographic appearances; Grade I being atheromatous irregularity only. Grade II a moderate stenosis but not significant in terms of local vessel flow. Grade III stenoses were thought to be significant in terms of local blood flow and Grade IV were complete occlusions.