Furosemide-augmented intravenous urography: results in essential hypertension

Giving an intravenous diuretic during urography (furosemide-augmented urography, vasodilated urography) causes renal swelling which is easily measured. Several investigators have used this observation as the basis of a screening test for renovascular hypertension. They found that normal kidneys enlarge in area by more than 10%, while kidneys with renal artery stenosis show a blunted size response, usually less than 5%. We used the technique in 46 patients with proven essential hypertension in order to further examine its potential usefulness in the hypertensive population. The 92 kidneys showed an average area increase of only 7.0% +/- 3.6% SD, and only 15% of the kidneys enlarged by more than 10%. Based on these observations we doubt that vasodilated urography will be valuable as a screening test for renovascular hypertension because of the high incidence of false positive and indeterminate results in patients without renal artery stenosis.