Renal hemodynamics and the renin--angiotensin system in cirrhosis: relationship to sodium retention.

Renal hemodynamics and the renin-angiotensin-aldosterone system were investigated in 15 cirrhotic patients without renal failure on controlled sodium intake of 140-160 mEq/day and related to the degree of sodium retention as measured by urinary sodium excretion. Fourteen patients were free of clinical ascites when studied. The distribution of renal blood flow was measured by the noninvasive technique of computerized radioisotope renography. In 11 patients, outer cortical renal plasma flow, expressed as a percentage of total effective renal plasma flow, was directly proportional to sodium excretion (P less than or equal to 0.01). Three patients with severe sodium retention (UNa.V less than or equal to 10 mEq) had estimated outer cortical renal plasma flows of less than or equal to 274 ml/min/1.73 M2 as compared to eight cirrhotics with better (UNa.V greater than or equal to 50 mEq) sodium tolerance (mean = 438 ml/min/1.73 M2). A significant inverse correlation (P less than or equal to 0.01) existed between outer renal cortical blood flow and plasma renin activity. No significant relationship was observed between glomerular filtration rate, total effective renal plasma flow, plasma aldosterone concentration and sodium excretion. These results provide further evidence that a renal vascular abnormality exists in cirrhosis, and that diminished outer cortical renal perfusion is related to the elevated renin levels and sodium intolerance observed in cirrhotic patients.