Transarterial wall oxygen gradients at the dog carotid bifurcation

The purpose of this study was to determine the effect of the carotid artery bifurcation on the delivery of oxygen to the artery wall by measuring the transarterial wall oxygen gradient. Transarterial wall oxygen gradient measurements were performed in dogs anesthetized with thiopental sodium and isoflurane by means of an oxygen microelectrode. Measurements 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 at the flow divider were increased throughout the artery wall compared with control locations. These effects were noted without differences in blood pressure, arterial blood oxygen tension, or histological evidence of atherosclerotic lesion formation. These findings suggest that the delivery of oxygen to the artery wall is altered by the bifurcation of the carotid artery. Low arterial oxygen tensions at the carotid sinus support a role for artery wall hypoxia in the formation of atherosclerotic lesions.