Effect of Posture on Renal Vein Renin Activity in Hypertension

The effect of posture on renal venous plasma renin activity was studied in a group of hypertensive patients. In patients with essential hypertension and in patients with renal artery stenosis bilaterally, upright posture did not augment the renin ratio in the two renal veins, but the rise in renin levels was greater in the patients with renal artery stenosis bilaterally. With one exception, all patients in upright posture who had unilateral arterial lesions exhibited a marked augmentation of the disparity in plasma renin activity values in the two renal veins. It is suggested that determination of plasma renin activity in renal venous blood procured from both kidneys while the patient is in the recumbent and then in the upright position may become of potential value in ascertaining the functional significance of renal arterial lesions especially in cases of renal artery branch stenosis.