We studied the interrelationships between systemic hemodynamics,
sodium excretion and the renin-angiotensin system in 28 nonazotemic cirrhotic patients on a
sodium restricted diet. Renal hemodynamics were also assessed. The patients were divided into three groups. Group A comprised 9 patients without
ascites or
edema; group B comprised 8 patients with
ascites and relatively high
sodium excretion (41.9 +/- 12.9 mmol/day); and group C comprised 11 patients with
ascites and very low
sodium excretion (4.8 +/- 12.9 mmol/day). There were no significant differences in urine flow, glomerular filtration rate or effective renal plasma flow between the three groups of patients, although
renin and
aldosterone levels were significantly increased in group C. Groups A and B did not differ in hemodynamic parameters and no differences were found between the three groups in heart rate or in plasma volume. Group C, however, showed significantly higher cardiac index and lower arterial pressure and systemic vascular resistance. Plasma volume was inversely related to systemic vascular resistance, and natriuresis correlated significantly with both cardiac index (inversely) and systemic vascular resistance (directly). In addition,
renin and
aldosterone levels were inversely correlated with both mean arterial pressure and systemic vascular resistance. The systemic hemodynamic disturbances in nonazotemic cirrhotics is paralleled by the impairment in
sodium homeostasis, suggesting that the decrease in systemic vascular resistance is the primary event leading to
hypotension,
high cardiac output and the activation of the renin-angiotensin system in these patients.