The plasma levels of atrial natriuretic factor in liver cirrhosis can be affected by various factors, such as ascites, renal function, use of diuretics drugs and dietary sodium intake. Moreover, the influence of high intra-abdominal pressure on cardiac atrial natriuretic factor release in patients with tense ascites has not been investigated. The aim of the present study was to evaluate the circulating levels of atrial natriuretic factor and their relationships to plasma renin activity, aldosterone concentration, and urinary sodium excretion in 45 cirrhotic patients divided into 4 groups: (a) cirrhotics without ascites; (b) nonazotemic cirrhotics with ascites; (c) cirrhotics with ascites and functional renal failure; and (d) cirrhotics with ascites taking diuretics. In some patients with tense ascites, atrial natriuretic factor was also measured after rapid abdominal relaxation by large volume paracentesis. Plasma levels of atrial natriuretic factor obtained in 13 healthy control subjects after 5 days on a 40-50 mEq sodium daily intake were 22.8 ± 3.3 pg/ml. Mean plasma atrial natriuretic factor levels were normal in patients without ascites (35.1 ± 11.4 pg/ml) and in those with ascites taking diuretics (27 ± 9.2 pg/ml), but elevated in patients with ascites not taking diuretics (59.6 ± 12 pg/ml) and in those with ascites and functional renal failure (58.5 ± 16.6 pg/ml). These data show that plasma atrial natriuretic factor levels are elevated only in cirrhotic patients who are ascitic and not taking diuretics. In these patients atrial natriuretic factor levels were directly correlated with urinary sodium excretion, even though sodium balance was positive. This could be the consequence of the contrasting effects of antinatriuretic factors, as suggested by the inverse relationships between atrial natriuretic factor and urinary sodium on the one hand and plasma renin activity and plasma aldosterone concentration on the other. Twenty-six patients with tense ascites (12 taking diuretics and 14 not) were treated with rapid large-volume paracentesis (6500 ± 330 ml of ascitic fluid removed in 168 ± 16 min). At the end of the procedure, plasma atrial natriuretic factor levels had increased in all patients (from 45.5 ± 10.1 to 100 ± 17 pg/ml), whereas plasma renin activity and plasma aldosterone concentration had decreased (from 10.3 ± 1.6 to 7 ± 1.3 ng/ml/h, and 1160 ± 197 to 781 ± 155 pg/ml, respectively). The marked increase observed in atrial natriuretic factor levels after paracentesis makes evident the presence of a consistent myocardial atrial natriuretic factor reserve in these patients, and, along with the decreases in plasma renin activity and plasma aldosterone concentration, suggests that the rapid relief of high intra-abdominal pressure increases central venous blood return and improves effective blood volume. On the basis of these findings, it is conceivable that tense ascites contributes to the imbalance between natriuretic and antinatriuretic factors in some patients with severe liver disease.
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