Renal Hemodynamics during Selective Renal Angiography

The effect of a contrast medium (60% Urografin) injected into the renal artery on the renal hemodynamics was studied in patients undergoing selective renal angiography and in dogs. It was found in the animal experiments that immediately following the injection there was a definite but variable reduction in renal blood flow, as determined by dye-dilution technique. There was no dose response relationship between the contrast material dose and the renal vasoconstriction. The vasoconstriction occurred even at doses used for selective renal angiograms (2 ml/100 ml renal blood flow) but was not potentiated with 10 to 15-fold increases in dose. The vasoconstriction was generally reversed within five to ten minutes. During the first 40 sec following contrast material injection there was a striking increase in the extraction factor of inulin and a moderate increase in the extraction factor of PAH. These results point to the postglomerular arterioles as the primary site of vasoconstriction. Results from the patient studies generally confirm the data from the animal experiments.