TRANSARTERIAL WALL OXYGEN GRADIENTS AT THE DOG CAROTID BIFURCATION

The purpose of this study was to determine the effect of the carotid a rtery bifurcation on the delivery of oxygen to the artery wall by meas uring the transarterial wall oxygen gradient. Transarterial wall oxyge n gradient measurements were performed in dogs anesthetized with thiop ental sodium and isoflurane by means of an oxygen microelectrode. Meas urements were performed at six locations along the carotid bifurcation . Oxygen tensions at the carotid sinus were decreased in the inner 40% of the artery wall compared with control locations. Oxygen tensions a t the flow divider were increased throughout the artery wall compared with control locations. These effects were noted without differences i n blood pressure, arterial blood oxygen tension, or histological evide nce of atherosclerotic lesion formation. These findings suggest that t he delivery of oxygen to the artery wall is altered by the bifurcation of the carotid artery. Low arterial oxygen tensions at the carotid si nus support a role for artery wall hypoxia in the formation of atheros clerotic lesions.