Improved diagnostic accuracy of renal venous renin ratios with stimulation of renin release.

Fifty patients who underwent renal angiography and bilateral renal venous determinations had reconstructive or ablative surgery. The importance of stimulating renin release was underlined in 11 patients who attained a renal venous ratio greater than 1.5 to 1 only after being in an upright posture and in 5 who were studied with and without salt depletion. A protocol designed to suppress or stimulate peripheral plasma renin activity was followed in 19 patients. Stimulated peripheral plasma renin activity was not useful in identifying hypertension of renovascular origin but 10 of 12 patients whose plasma renin activity was not suppressed normally were improved by an operation. Satisfactory surgical responses were obtained in 81 per cent of the patients with unilateral and 91 per cent with bilateral atherosclerosis, and 88 per cent with unilateral and 60 per cent with bilateral fibromuscular hyperplasia. Our observations indicate that renal artery stenosis can be identified consistently only by angiography. A stimulated renal venous renin rate of 1.5 to 1 appears to have the best predictive value in surgical control of renovascular hypertension.