The conditions of 25 patients with external arteriovenous shunts were studied to determine the factors important in control of shunt flow. Shunt flow varied between 1.9% and 9.8% of the cardiac output in seven studies performed in five patients. Change in posture, exercise, and dialysis had no consistent effect on shunt flow. Flow was primarily determined by systemic pressure, vascular reactivity, and the state of the cannulated vessels. Cold pressor test and angiotensin amide consistently increased flow in contrast to the fall in flow and increased shunt pressure induced with sympathomimetic agents. Studies in dogs demonstrated that the changes induced with the sympathomimetic agents were a consequence of arterial and venous constriction mediated through alpha-adrenergic receptors. Shunt flow and pressure measurements appeared to be useful in predicting shunt survival and determining the involved side of a malfunctioning shunt.
Alfrey AC, Lueker R, Goss JE, Vogel JHK, Faris TD, Holmes JH. Control of Arteriovenous Shunt Flow. JAMA. 1970;214(5):884–888. doi:10.1001/jama.1970.03180050040007