Influence of contrast material on renal venous renin activity.

The influence of contrast material on renal venous renin activity was evaluated in a prospective study of 20 hypertensive patients. It is concluded that the absolute values of renal venous renin activity are either unchanged or unpredictably changed after injection of contrast material. The renal venous renin activity ratios seem to be less valid than the absolute values in predicting the significance of renal vascular or parenchymal disease.