Hypertensive urogram: a nondiscriminatory test for renovascular hypertension

Evidence has accumulated from clinical experience that the hypertensive urogram is not a satisfactory screening test for differentiating hypertension due to renal artery stenosis from essential hypertension. This is contrary to the conclusion reached in the report of the Cooperative Study published in 1972. The present investigation was done to: (1) reassess the value of the hypertensive urogram on the basis of experience at a single institution and (2) to reassess the validity of the Cooperative Study conclusions. In 197 patients operated on at the University of Michigan for renal artery stenosis during 1961-1977, the true-positive rate for hypertensive urography for prediction of surgical cure or improvement was 60.2%. In 131 patients undergoing hypertensive urography in 1977, the incidence of positive examinations in screening was 0.8%. The chance for a favorable surgical outcome in hypertensive patients having positive hypertensive urograms is now calculated as 24%, rather than 50% as stated in the Cooperative Study. Reanalysis of the Cooperative Study data also shows that the false-negative rate for screening is at least 21.8%, rather than 1.7%. A screening strategy fo choosing patients for renal arteriography and surgery on the basis of clinical factors and excluding urography is presented.