Vascular dynamics of an experimental cerebral arteriovenous shunt in the primate.

An arteriovenous fistula which shunted arterial blood from the circle of Willis to the internal jugular vein was created in ten monkeys. Continued patency of the shunt was confirmed angiographically. Cerebral blood flow measurements were then obtained with the shunt both open and occluded. Flow was also determined in response to elevations of systemic arterial pressure and raised arterial carbon dioxide tensions (PaCO2), again with the shunt both patent and occluded. In addition, flow through the shunt alone was measured in response to elevations of systemic arterial pressure and PaCO2. The results suggest that flow through our arteriovenous shunt is minimally autoregulated to changes in systemic arterial pressure and is only slightly responsive to changes in PaCO2.