engleski

Atrial stretch is the principal determinant controlling the acute release of atrial natriuretic peptide in the liver cirrhosis

Introduction. Atrial natriuretic peptide (ANP), a hormon secreted by the cardiac atria in response to changes in pressure as measured by stretch receptors in the atria wall, has a spectrum of renal, hemodynamic and endocrine actions, all of which serve to reduce the elevated blood volume. In patients (pts) with liver cirrhosis, plasma concentrations of ANP are attributable to several factors: high blood volume, effective hypovolemia, hyperdynamic circulation, posture, intra-abdominal and intra-thoracic pressure, sodium intake and drug administration. The aim of the study was to assess post-paracentesis hemodynamic and neurohumoral changes and the influence of the paracentesis, bed rest 24 h before and after the procedure, and volume replacement on the acute release of ANP in pts with tense ascites in Child-Pugh C liver cirrhosis. Methods. Forty pts with Child-Pugh C liver cirrhosis and tense ascites, without toxic cardiomyopathy, were randomly allocated into 4 groups. Thirty pts were treated with paracentesis of 6 L of ascites paralleled by plasma volume expansion with 200 mL of 20% low sodium albumin (10 pts), 600 mL fresh frozen plasma (10 pts), or 900 mL solution of synthetic gelatine (10 pts), ie doses with comparable oncotic power, and bed rest for 24 h before and after the procedure. They were compared with 10 pts treated with paracentesis of 6 L of ascites, without plasma volume expansion and no bed rest. Mean arterial pressure, heart rate, plasma renin activity, plasma aldosterone concentration, plasma ANP, urine flow rate and creatinine clearance were measured before the procedure, and 6 hours, 2, 3 and 6 days after the procedure. Results. Paracentesis of 6 L of ascites without plasma volume expansion and no bed rest 24 h before and after the procedure was associated with significant hypotension (p<0.01) during 6 days of the trial, tachycardia (p<0.01) on day 1 and 2 (p=0.012), increase in plasma renin activity 6 hours after the beginning of the study (p=0.025) and on day 6 (p=0.024), increase in plasma aldosterone concentration on day 6 (p=0.030), no significant change in plasma ANP levels, and decrease in creatinine clearance on day 6 (p=0.046). Albumin was superior to the other plasma expanders. Comparison between groups treated with plasma volume expansion did not show significant differences in measured parameters at any time during the study. The differences were found in the amount of needed volume of each substitute, daily sodium balance on day 1 of the trial, increase in plasma aldosterone concentration in bed rest-paracentesis-polygeline group on day 6 and the increase in plasma ANP on day 1 (p=0.077), which was proportional to the amount of infused volume. There was no significant differences in basic plasma ANP levels (pg/mL) between groups bed rest-paracentesis-albumin/plasma/polygeline (38.87+/-67.84) and group no bed rest-paracentesis (18.60+/-18.86). Six hours after the procedure there were marked, but not significant increase in plasma ANP for groups bed rest-paracentesis-albumin (50.40+/-27.33), bed rest-paracentesis-plasma (54.60+/-88.40) and bed rest-paracentesis-polygeline (72.90+/-118.82) in contrast to group no bed rest-paracentesis (23.90+/-20.03). On day 2 of the trial ANP levels were: groups bed rest-paracentesis-albumin/plasma/polygeline (42.20+/-88.03) and group no bed rest-paracentesis (12.80+/-8.57). On day 3 of the trial ANP levels had further decreases for groups bed rest-paracentesis-albumin/plasma/polygeline (35.67+/-66.42), but they were never as low as in group no bed rest-paracentesis (16.00+/-16.65). On day 6 of the trial plasma ANP levels were similar to the basic levels for all groups: bed rest-paracentesis-albumin/plasma-polygeline (35.30+/-61.71) and no bed rest-paracentesis (15.20+/-11.60). Conclusion. Therapeutic paracentesis of 6 L of ascites, bed rest 24 h before and after the procedure, and intravenous substitution of volume with albumin, fresh frozen plasma, and solution of synthetic geletine were safe, rapid, and effective treatments, provided that intravascular volume was substituted simultaneously. Cardiac release of ANP in response to volume expansion was not impaired in patients with Child-Pugh C liver cirrhosis and tense ascites. The main mechanism stimulating the acute release of ANP was atrial stretching, induced with volume expansion and was proportional to its amount.

liver cirrhosis; therapy; ascites; therapy; paracentesis; volume replacement; atrial strech; atrial natriuretic peptide

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