Effects of radiopaque dyes on renal vascular resistance.

Abstract

Abstract Radiopaque contrast medium (diatrizoate, 50 per cent, or iodopyracet, 45 per cent) was injected into the renal artery; renal vascular resistance and urine flow were measured in naturally perfused and pump-perfused canine kidneys. Bolus injections of hyperosmotic solutions contrast medium, NaCl (sodium chloride), or urea increased renal vascular resistance for 2 to more than 20 minutes in both preparations. Blood flow was decreased in naturally perfused kidneys and perfusion pressure was increased in pump-perfused kidneys. The magnitude and duration of this response varied directly with the control resistance. The greater the control resistance, the greater was the response. The rise in renal resistance was accompanied regularly by a rise in urine flow and less frequently by gross hematuria and a transient increase in aortic pressure. Injections of isosmotic solutions of the contrast medium or NaCl did not alter renal resistance. Slow infusion of hyperosmotic contrast medium lowered renal resistance. These studies indicate that the rise in renal vascular resistance was dependent on the rate and amount of contrast medium injected and on the control resistance. It is suggested that renal arteriography be done with caution in patients whose renal vascular resistance is likely to be high.