The hemodynamics of extra-anatomic bypass grafts.

The hemodynamics of extra-anatomic bypass were studied with the use of right to left iliac artery bypass grafts. An arteriovenous fistula on the recipient side was used to increase the flow through the graft. Flow measurements in this model under normotensive conditions showed proportionate increases in the suprarenal aortic blood flow and in the blood flow through the segment of donor artery proximal to the bypass graft anastomosis. Stealing of blood was not observed even when the graft flow was increased to approximately 11 times the normal flow in the donor artery. Arfonad was used for producing hypotension through vasodilatation. In the presence of peripheral vasodilatation, adequate blood flow can be expected after such bypass grafts at blood pressures as low as 80 millimeters of mercury and hypotension per se does not produce vascular steal.