THE EXERCISE RENOGRAM AND ITS INTERPRETATION

The exercise renogram is a rarely used diagnostic procedure, but it ma y visualize an exercise-induced change in renal function related to th e pathophysiology of essential hypertension, which could greatly incre ase interest in this examination. The aim of this study was to demonst rate the interpretative approach and the terminology which is used to describe results of exercise renography, using a population of hyperte nsives with renovascular disease. Methods: We reviewed the examination s of 70 hypertensives who had supine renography as well as exercise re nography with a 60-80 W work load. Forty-eight patients were examined with Tc-99m-MAG3 and 22 with I-131 hippurate. The renographic and angi ography results were recorded as well as the antihypertensive drugs us ed and the site of vascular lesions. Results: Thirty-three hypertensiv es developed a bilateral-abnormal exercise renogram, which appears to be associated with primary hypertension. Eight individuals responded t o exercise with a unilateral-abnormal exercise renogram, in a kidney b ehind a stenosis. Only 19 patients had a normal exercise renogram, and 10 had only one functioning kidney. Pathology recognized but unrelate d to the intervention included nonfunctioning and small kidneys and pe lvic retention. Conclusion: Exercise renography's only indication is f or recognition of pathology unique to hypertension, since other functi on disturbances were recognized in resting renograms.