The effect of two intra-arterially injected vasodilating agents on the oxygen uptake of tissue and on blood flow through a critical stenosis has been investigated in the dog. Blood flow increase always occurred through the stenotic segment, but this change was small. Concomitant with this small flow increase the oxygen consumption of the tissue distal to the stenosis was found to be significantly decreased by the vasodilator infusion. This decreased oxygen consumption was manifested by marked narrowing of the arteriovenous oxyhemoglobin difference, suggesting that the agents infused opened arteriovenous shunts.
Kreuzer W, Schenk WG. Hemodynamic Effects of Vasodilatation in "Critical" Arterial Stenosis. Arch Surg. 1971;103(2):277-282. doi:10.1001/archsurg.1971.01350080193030