Role of the renin-angiotensin-aldosterone system in hypertensive children with coarctation of the aorta.

To investigate the role of the renin-angiotensin-aldosterone system as a cause of hypertension, 20 hypertensive patients with coarctation of the aorta were studied during normal and low sodium intake and after diuresis with flurosemide. Eight patients with essential hypertension and 13 control subjects were similarly studied. Plasma renin activity values in patients with coarctation were similar to those in patients with essential hypertension and in control patients during normal and low sodium diets. However, after the administration of furosemide, plasma renin activity values were significantly higher in the patients with coarctation than in the other two groups (P less than 0.005 and less than 0.01, respectively). The values for urinary aldosterone, plasma volume and extracell fluid volume (bromide space) were increased in patients with coarctation during both normal and low sodium intake. These renin and aldosterone responses and body fluid spaces in patients with coarctation suggest that their hypertension resembles a one-kidney Goldblatt model. The data help to better define the role of the renin-angiotensin-aldosterone system in the hypertension of coarctation and thus may help guide the clinician in therapeutic interventions.