Effects of furosemide on renal venous plasma renin activity.

A control study comparing plasma renin activity (PRA) in the renal vein and the inferior vena cava was performed in 50 hypertensive patients before and after furosemide stimulation. In unilateral renal arterial stenosis, furosemide was found to stimulate secretion by the normal kidney more than by the ischemic kidney. When a renal venin PRA ratio of 1.5 or higher was used for lateralization, rates of 30% false-negatives and 60% false-positive resulted. Acute stimulation of renin by furosemide does not increase the predictive value of renal venous renin measurements and may actually result in a higher percentage of false-negatives.