The exercise renogram. A new approach documents renal involvement in systemic hypertension.

Hippurate functional scintiscans were obtained in 51 hypertensive patients and in 15 controls. We investigated the influence that posture and exercise have on hippurate kinetics in patients with hypertension. A posture- or exercise-induced disturbance of renal hippurate transport was sought. All persons were examined in prone and standing positions, as well as during exercise. When prone and upright renograms were compared, 24% of the hypertensives demonstrated bilateral orthostatic renal dysfunction. Exercise caused the hippurate transport disturbance to increase. Fifty-seven percent of all hypertensives developed evidence of marked, bilateral, renal dysfunction during ergometric stress, so that exercise renography was shown to be a more sensitive test of the presence of transient tubular dysfunction in hypertension than the standing renogram. In normotensive controls the hippurate functional scintigram failed to be influenced by posture and exercise. The results suggest presence in hypertension of transient, posture- and exercise-mediated alterations of renal cortical blood flow.