Washout Urography: Its Value in the Diagnosis of Renovascular Hypertension

Abstract

Washout urography was used as a screening test in 805 hypertensive patients. Its value in the diagnosis of renovascular hypertension was evaluated from 124, of these patients who had renal aortography in close time relation to the urographic examination. In 22 cases the diagnosis of renovascular hypertension was verified by operation and postoperative follow-up. Sixty five patients had normal renal arteries. The washout test was positive in 95% of cases with proven renovascular hypertension and in 9% of the cases with normal renal arteries. Blood pressure was unchanged after operation in 5 patients. Four of these had normal washout tests preoperatively. These results were more favourable than those obtained from other urographic features such as differences in kidney length and early excretion rate (one minute sequence filming), and isotope renography. If difference in early excretion rate is used as a single diagnostic criterion, the intervals between exposures should be shorter than one minute. As a radiological parallel to renal split function tests, washout urography yields valuable information on renal function as well as morphology. In spite of discouraging results in previous communicalions, the test is recommended as a screening procedure in hypertensive patients. A simplified version of the washout urography with few exposures is suggested.