A canine hind-limb exercise model is described that permits study of pressure and flow changes through an area of arterial stenosis before, during, and after exercise.
Following creation of a critical stenosis in the external iliac artery (50% reduction in flow), exercise alone resulted in an increase in flow over the stenosis related to the degree of exercise produced, accompanied by a widening of the arteriovenous oxygen difference and an increase in oxygen consumption.
Infusion of an intra-arterial vasodilator (tolazoline hydrochloride) during the exercise period resulted in only a negligible change in flow over the stenosis, but a marked narrowing of the arteriovenous difference (30%) with a resulting reduction in limb oxygen consumption.
These findings suggest that this intraarterial vasodilator opens arteriovenous shunts, apparently bypassing the capillary bed.
Weissenhofer W, Schenk WG. Hemodynamic Response to Vasodilation and Exercise in "Critical" Arterial StenosisAn Experimental Study in a Canine Model. Arch Surg. 1974;108(5):712-714. doi:10.1001/archsurg.1974.01350290074012