Clinical and hormonal conditions associated with sodium retention in cirrhotic patients with ascites. Evaluation by univariate and multivariate analyses

Circadian rhythms of plasma atriopeptin, plasma renin activity and plasma aldosterone in patients with hepatorenal syndrome

The etiology of hepatorenal syndrome (HRS) is still incompletely understood, but the atriopeptin-renin-aldosterone system plays an important role in its pathogenesis. Since this system presents a circadian rhythmicity, the aim of the study was to investigate the circadian rhythm in the circulating concentrations of atriopeptin (atrial natriuretic peptide, pANP), plasma renin activity (PRA) and plasma aldosterone (pA) in patients with HRS, compared with healthy controls. Venous blood samples were drawn during the span of a whole day and every two hours from a peripheral vein in 10 healthy subjects and in 10 patients with HRS. The circulating concentrations of pANP, PRA and pA were determined by radioimmunoassay. Statistical analysis was carried out by the "cosinor" method. The controls presented a significant (p < 0.05) circadian rhythm for each variable, whereas no rhythm (p > 0.05) was found in HRS patients. The pANP, PRA and pA rhythms were significantly (p < 0.05) different between the two groups, HRS patients having higher mean daily concentrations and larger circadian variations of pANP, PRA and pA than controls. Significant relations (p < 0.05) were demonstrated between the mean daily concentrations of pANP and PRA (r = 0.79), PRA and pA (r = 0.73) and PRA and pA (r = 0.76) in the controls; on the contrary, the HRS patients showed only a significant (p < 0.05) positive relation between pANP and PRA (r = 0.71). These results confirm the previous observation that the atriopeptin-renin- aldosterone system presents a well-defined circadian time structure in healthy subjects, while the HRS patients present a complete loss of the secretory sequentiality and of the circadian rhythm, with desynchronization of the whole system. This great upset in the temporal and functional organizations of the system could play an important role in promoting and/or in maintaining the hydro-electrolyte unbalance of HRS.

Antidiuretic hormone and renal function after water loading in patients with cirrhosis of the liver

Renal function and plasma antidiuretic hormone (ADH) levels were studied basally and after oral water load in four groups of subjects: 15 healthy controls (group I), 15 cirrhotics without ascites (group II), 15 cirrhotics with ascites (group III), and 10 decompensated cirrhotics with hyponatremia (group IV). Renal function and ADH levels were normal in group II. In groups III and IV water diuresis and fractional proximal sodium excretion were significantly decreased, whereas fractional distal sodium resorption and fractional excretion of potassium did not differ from those of controls. Basal ADH was significantly increased only in patients of group IV. In these patients ADH remained abnormally high after water loading. ADH did not correlate with water diuresis, plasma osmolality, mean arterial pressure, and plasma renin activity. We conclude that impaired water excretion in decompensated cirrhotics without hyponatremia cannot be ascribed to high serum levels of ADH. On the contrary, it seems to be related mainly to a reduced delivery of filtrate to the diluting segment of the nephron. In cirrhotic patients with hyponatremia high levels of ADH may play an additional role.

Mechanisms of hypertension during and after orthotopic liver transplantation in children

The aim of this study was to assess the hormonal alterations that may mediate the systemic hypertension that develops in patients during the perioperative period of orthotopic liver transplantation. We studied nine pediatric patients without previous hypertension or renal disease during six time points, starting before transplantation and ending at 48 hours after surgery. Hypertension developed in all patients in association with central venous pressures less than 10 mm Hg. Free water clearance was negative in all nine patients. Vasopressin levels increased intraoperatively but fell as hypertension developed. Atrial natriuretic factor levels increased as systemic blood pressure rose. A high level of plasma renin activity was observed in four patients with renal insufficiency. In six patients, postoperative 24-hour urinary norepinephrine excretion was within the normal age-adjusted range. These findings suggest that the combination of cyclosporine, corticosteroids, and, in some patients, an elevated plasma renin activity prevents the kidney from responding to the acute volume and salt overload with an appropriate diuresis and natriuresis, thus leading to systemic hypertension. The treatment of hypertension after liver transplantation may include salt restriction, diuretics, and, in those patients with a low creatinine excretion index, angiotensin coverting enzyme inhibitors.

Manipulation of ascitic fluid pressure in cirrhotics to optimize hemodynamic and renal function

Intra-abdominal pressure (IAP), measured via a transurethral catheter, hemodynamic, and renal functions were evaluated in 25 cirrhotic patients admitted to ICU with variceal bleeding, tense ascites, and peripheral edema. In patients with an IAP greater than 25 cm H2O, a paracentesis was performed to decrease the IAP by 10 cm H2O. After paracentesis, a decrease in the IAP from 33.47 to 19.06 cm H2O (p less than 0.001) resulted in a decrease in total peripheral resistance (TPR) (p less than 0.01) and a significant increase in cardiac index (CI) (p less than 0.001), stroke index (p less than 0.001), left ventricular stroke work (LVSW) (p less than 0.01), and right ventricular stroke work (p less than 0.01). The therapeutic effects of paracentesis on renal function were: a decrease in BUN and serum creatinine (p less than 0.001) and an increase in the creatinine clearance (Ccr) (p less than 0.001), urine volume (p less than 0.001), osmolar clearance (Cosm) (p less than 0.001), and urine creatinine (p less than 0.001) values. The IAP correlated directly with the TPR (r = +0.35, p less than 0.01) and inversely with the CI (r = -0.39, p less than 0.001) and LVSW (r = -0.37, p less than 0.001) in the 126 studies of IAP performed with the 25 patients. IAP also correlated directly with BUN (r = 0.40, p less than 0.001), serum creatinine (r = 0.28, p less than 0.01), and free water clearance (CH2O) (r = 0.3, p less than 0.001); IAP correlated negatively with Ccr (r = -0.54, p less than 0.001) and Cosm (r = -0.43, p less than 0.001). In critically ill cirrhotic patients, IAP, when measured noninvasively via a bladder catheter, is an accurate and useful method to follow manipulation of ascitic fluid pressure quantitatively in order to optimize hemodynamic and renal function.