[Adrenaline and noradrenaline excretion during angiotensin II infusions into the carotid artery of anesthetized dogs]

Hypertension in terminal renal failure

Inverse interrelations between plasma renin activity and exchangeable sodium or blood volume were found in both normotensive (N = 23) and hypertensive (N =29) hemodialysis patients (r= 0.47; P less than 0.005); however, mean plasma renin for any given sodium/volume state was at least two-fold higher in hypertensive than in normotensive hemodialysis patients or normal subjects (N =31). In the hemodialysis patients, blood pressure correlated weakly but significantly with the products of circulating renin and exchangeable sodium (r=0.37; P less than 0.005) or blood volume (r = 0.29; P less than 0.05). Multiple regression analysis including duration of previous hypertension as the second independent variable increased these correlation coefficients to 0.44 and 0.42, respectively. This suggests that hypertension in endstage kidney disease is often associated with resetting of the body sodium/fluid=renin feedback mechanism. Inappropriately increased plasma renine activity relative to the body sodium/volume state as well as high blood pressure-induced vascular changes may play important complementary roles, but it appears evident that additional mechanisms are also operative in maintaining end-stage renal hypertension.

Plasma renin activity in patients with coarctation of the aorta. A comment of the pathogenesis prestenotic hypertension

In 10 patients with coarctation of the aorta, plasma renin activity was measured after recumbency and orthostatism in peripheral venous blood and, in some cases, in renal venous blood also. In nine of these patients, basic plasma renin values and those obtained under stimulatory conditions lay within normal range, and only in one patient were the values elevated. However, since this patient displayed the lowest gradient of mean arterial blood pressure proximal and distal to the stenosis, it can be regarded as improbable that the elevation in plasma renin activity was caused by the coarctation. Plasma renin activity in the renal venous blood of both kidneys, which was measured in three patients, showed no elevation.

On the basis of observations of other authors and of our own studies it can be concluded that the kidneys can contribute to the development of prestenotic hypertension in acute constriction of the aorta in experiments with animals, but in chronic coarctation in animals or in man the humoral or renal theory has no importance to the pathogenesis of hypertension.