SENSITIVITY AND SPECIFICITY OF SCREENING-TESTS FOR RENAL VASCULAR HYPERTENSION

To facilitate the identification of patients with renal vascular hypertension, the authors evaluated four potential screening tests: rapid-sequence urography, systolic-diastolic abdominal bruit, upright plasma renin activity (PRA), and response to saralasin infusion. Their study included 379 normal subjects, 199 essential hypertensive patients with normal renal angiograms, and 64 patients with surgically responsive renal vascular hypertension. Thirty-nine percent of patients with renal vascular hypertension had systolic-diastolic bruits, 76% abnormal urograms, and 27% a PRA > 30 ng of angiotensin I/mL/3 hr. Only one half of the 23 patients with renal vascular hypertension tested had a depressor response to saralasin, as did two of 13 essential hypertensive patients. In essential hypertensive subjects, 1% had systolic-diastolic bruits, 2% abnormal urograms, and 5% upright renin values > 30 ng of angiotensin I/mL/3 hr. The screening combination of urogram, bruit, or upright renin value offered a test sensitivity of 93%, with a specificity of 92%. The results of saralasin infusion failed to increase the diagnostic yield.