[The factors that regulate water-salt metabolism in congestive heart failure].

We investigated the mechanisms involved in the regulation of salt and water metabolism in patients with congestive heart failure (CHF). Extracorporeal ultrafiltration was utilized as a nonpharmacologic method for withdrawal of body fluids. In 32 consecutive patients with CHF (NYHA class II to IV) and different degrees of water retention, 24-hour diuresis and natriuresis were inversely best correlated with the combination of circulating renin, aldosterone, norepinephrine, and renal perfusion pressure (RPP). Fluid removal (600 to 5,000 ml) at a rate of 500 ml/h, until right atrial pressure decreased to 50% of baseline, caused variable humoral, circulatory, and diuretic effects that were mainly related to the extent of fluid retention. In fact, in 10 patients (Group 1) with overhydration refractory to drug therapy and with urinary output less than 1,000 ml/24 h (mean 370 ml), soon after the procedure, plasma renin (-39%), aldosterone (-50%), and norepinephrine (-47%) were reduced and RPP was increased (+ 16%), and in the subsequent 24 hours, diuresis was increased by 493%; in 9 patients (Group 2) whose baseline urinary output exceeded 1,000 ml/24 h (mean 1,785 ml), renin increased by 40%, norepinephrine, aldosterone and RPP each decreased by 12%, and diuresis remained unchanged; in 13 patients (Group 3) with a daily urinary excretion as in Group 2 and without overhydration, RPP decreased (-7%), renin (+ 196%), aldosterone (+ 170%), and norepinephrine (+ 52%) increased, and diuresis decreased by 45%. There was an overall correlation (p < 0.0001) between the combination of changes in these circulatory and hormonal variables and changes in diuresis and natriuresis with ultrafiltration.(ABSTRACT TRUNCATED AT 250 WORDS)