[Improved interpretation of renal-vein-renin-ratio by simultaneous determination of renal 131I-hippuric-acid-clearance-ratio in patients with renovascular hypertension (author's transl)].

In patients with unilateral vascular kidney disease and hypertension, ratio of renal-vein-renin was compared with 131I-Hippuric-acid clearance and change in blood pressure during Saralasininfusion. The ratio of renal-vein-renin was positively correlated with the ratio in renal plasma flow between the kidneys in all patients studied. The ratio of renins therefore is a result of two factors: The difference in renin secretion and the difference in blood flow in the two kidneys. In patients with angiotensin independent hypertension renin-ratios up to 2.0 were found without relevance to elevated blood pressure. When the difference in renal blood flow between both kidneys was small, even a slight difference in renal vein renin indicated hypertension related to increased renin secretion. Renin-ratios in the critical range between 1.5 and 2.5 should only be interpreted in respect to a similar ratio in renal blood flow.