CIRCULATORY VOLUME IN ESSENTIAL-HYPERTENSION - RELATIONSHIPS WITH AGE, BLOOD-PRESSURE, EXCHANGEABLE SODIUM, RENIN, ALDOSTERONE AND CATECHOLAMINES

  • 1 January 1984
    • journal article
    • research article
    • Vol. 10  (5) , 292-300
Abstract
The circulatory volume and exchangeable Na were measured in 110 normal subjects and 120 patients with benign untreated essential hypertension. The 2 study groups did not differ in age, Na and K metabolism, and plasma levels of renin, aldosterone and norepinephrine, while plasma epinephrine was slightly higher in essential hypertension. Total plasma and blood volume correlated with total exchangeable Na (r = 0.64-0.75; P < 0.001); these correlations were similar in normal and hypertensive subjects. Body surface area was found to be the most appropriate frame of reference for judging individual values of plasma and blood volume or exchangeable Na; using this approach these body constituents were on average normal in the hypertensive population. Blood volume was unrelated to age or blood pressure in normal and hypertensive subjects. Exchangeable Na tended to increase with age (r = 0.25; P < 0.02) and correlated positively with blood pressure (r = 0.25; P < 0.02) in essential hypertension but not in normal subjects. The latter body constituent was slightly but significantly decreased in hypertensive males aged < 35 yr as compared with appropriate normal controls (96.1 .+-. 6.8% vs. 99.6 .+-. 6.7%; P < 0.05). Blood volume and exchangeable Na; apparently are on average normal in patients with benign essential hypertension. Body Na may even be decreased in certain young hypertensive patients. These observations do not support the concept that hypervolemia may represent the initial event leading to high blood presure in essential hypertension; in contrast, changes in blood volume appear to reflect variations in blood pressure.