Atrial natriuretic factor in cirrhotic patients with tense ascites. Effect of large-volume paracentesis

Management of refractory ascites in cirrhosis: Are we out of date?

Cirrhosis is a major cause of morbidity and mortality worldwide with liver transplantations as it only possible cure. In the face of a significant organ shortage many patients die waiting. A major complication of cirrhosis is the development of portal hypertension and ascites. The management of ascites has barely evolved over the last hundred years and includes only a few milestones in our treatment approach, but has overall significantly improved patient morbidity and survival. Our mainstay to ascites management includes changes in diet, diuretics, shunt procedures, and large volume paracentesis. The understanding of the pathophysiology of cirrhosis and portal hypertension has significantly improved in the last couple of decades but the changes in ascites management have not seemed to mirror this newer knowledge. We herein review the history of ascites management and discuss some its current limitations.

Increased flow-mediated vasodilation in cirrhotic patients with ascites: relationship with renal resistive index

BACKGROUND

Peripheral vasodilation is the key factor in the development of hyperdynamic circulation, sodium retention and functional renal failure in patients with cirrhosis. Brachial artery flow-mediated dilation (FMD) after transient vascular occlusion is a non-invasive method to assess the shear stress-induced arterial vasodilation.

AIMS

To evaluate FMD in cirrhotic patients with and without ascites and to assess the relationship between FMD and intrarenal resistances.

METHODS

Flow-mediated dilation was determined in 32 cirrhotic patients (22 with ascites) and 12 healthy controls and correlated with the intrarenal resistive index (RI) assessed by Doppler exploration.

RESULTS

Basal diameter of the brachial artery was similar in healthy controls and in cirrhotic patients, whereas FMD was significantly higher in patients with cirrhosis and ascites [29.5% (range 10.3-50%)] than in pre-ascitic patients [17.3% (range 2.4-48.5%)] and healthy control subjects [11.6% (range 5.1-17.8%)] (P<0.001). Intrarenal RI was significantly higher in patients with cirrhosis than in healthy subjects, and a direct relationship existed between FMD and intrarenal RI (r=0.66; P<0.00001).

CONCLUSIONS

These findings in vivo demonstrate that cirrhotic patients with ascites have an enhanced shear stress-induced peripheral vasodilation, which is closely related to intrarenal vasoconstriction.

Prevention of Renal Impairment by Continuous Infusion of Human Atrial Natriuretic Peptide after Liver Transplantation

BACKGROUND

Acute renal failure occurring immediately after liver transplantation and requiring hemodialysis is a major problem resulting in a poor prognosis. We investigated the efficacy of human atrial natriuretic peptide, which has potent natriuretic effects and unique protective effects for glomeruli in preventing acute renal failure after liver transplantation.

METHODS

Thirty-seven patients who underwent live donor liver transplantation with model for end-stage liver disease scores greater than 15 were the subjects of the study. Subjects were prospectively randomized into two groups: patients that received synthetic human atrial natriuretic peptide infusion (Group H: n=19) and those that received conventional diuretics, furosemide and potassium canrenoate (Group C: n=18). The peri- and postoperative changes in hemodynamic status and renal function were compared between the two groups.

RESULTS

There were no statistical differences in the changes in hemodynamic status between groups. Hemodialysis was required after liver transplantation in nine patients, two in Group H and seven in Group C (P=0.04). Postoperative creatinine clearance was higher in Group H (P=0.03). Aldosterone level was suppressed in group H (P=0.006).

CONCLUSIONS

Continuous infusion of synthetic human atrial natriuretic peptide might be effective for preventing acute renal failure requiring hemodialysis after liver transplantation.

Humoral and cardiac effects of TIPS in cirrhotic patients with different "effective" blood volume

The aim of this study was to evaluate the cardiac effects of transjugular intrahepatic portosystemic shunts (TIPS) in cirrhotic patients with different effective blood volume. Two-dimensional echocardiography was performed before and 7 and 28 days after TIPS insertion in 7 cirrhotic patients with PRA <4 ng/mL/h (group A, normal effective blood volume) and 15 with PRA >4 ng/mL/h (group B, reduced effective blood volume). Before TIPS, most cirrhotic patients showed diastolic dysfunction as indicated by reduced early maximal ventricular filling velocity (E)/late filling velocity (A) ratio. Patients of group B differed from patients of group A because of smaller left ventricular volumes and stroke volume, indicating central underfilling. After TIPS insertion, portal decompression was associated with a significant increase of cardiac output (CO) and a decrease of peripheral resistances. The most important changes were recorded in patients of group B, who showed a significant increase of both the end-diastolic left ventricular volumes and the E/A ratio and a significant decrease of PRA. In conclusion, these results show that the hemodynamic effects of TIPS differ according to the pre-TIPS effective blood volume. Furthermore, TIPS improves the diastolic cardiac function of cirrhotic patients with effective hypovolemia. This result is likely due to a TIPS-related improvement of the fullness of central blood volume.

Nadolol is superior to isosorbide mononitrate for the prevention of the first variceal bleeding in cirrhotic patients with ascites

BACKGROUND/AIMS

beta-blockers effectively prevent first variceal bleeding (FVB) in cirrhotic patients. In patients with ascites, however, their use might be precluded by a high rate of contraindications and side effects. We compared the efficacy and applicability of nadolol and isosorbide-mononitrate (IsMn) in preventing FVB in a population of cirrhotic patients at high risk of variceal bleeding with ascites, who can be frequently intolerant to beta-blockers.

METHODS

A total of 80 consecutive cirrhotic patients with ascites and esophageal varices (25% average risk of bleeding at 1 year) were considered, 28 were excluded due to contraindications and 52 were randomly assigned to receive nadolol (n=25) or IsMn (n=27).

RESULTS

Frequency of contraindications was greater for beta-blockers than IsMn (35 versus 0%, P=0.001). During 21.3+/-11.6 months of follow-up, side effects forced six patients taking nadolol and four taking IsMn to stop treatment. Bleeding occurred in two patients taking nadolol and ten taking IsMn. The probability of bleeding was significantly lower in the nadolol group (P<0.05), whereas overall survival was similar (seven patients on IsMn and eight on nadolol died, P=0.3).

CONCLUSIONS

In patients with ascites IsMn is tolerated but ineffective while nadolol is effective but less tolerated.

High plasma cardiac natriuretic peptides associated with enhanced cyclic guanosine monophosphate production in preascitic cirrhosis

BACKGROUND/AIMS

The initial abnormalities of renal sodium handling in cirrhosis remain unclear. The aim of this study was to characterize sodium metabolism in preascitic cirrhosis.

METHODS

Ten patients with preascitic cirrhosis and ten controls were studied. All subjects ate a diet providing 120 mmol sodium during an equilibration period lasting 5 days and the study day. On the study day, after remaining in bed, plasma levels of atrial natriuretic peptide, brain natriuretic peptide, renin activity, aldosterone, noradrenaline, and cyclic guanosine monophosphate were measured at 7 am. Thereafter, they were instructed to maintain an upright posture until dinner and the measurements were repeated at 9 am and 6 pm. After having dinner, all subjects were asked to remain in bed and the measurements were repeated at 11 pm. To measure renal sodium and cyclic guanosine monophosphate excretion, 24-h urine collections were performed, starting from 7 pm on the day before the experimental day.

RESULTS

Plasma levels of atrial natriuretic peptide, brain natriuretic peptide and cyclic guanosine monophosphate in patients with preascitic cirrhosis were significantly elevated compared with those in controls at every sampling time (p=0.03 or less, p= 0.04 or less, and p=0.01 or less). In contrast, plasma renin activities at every sampling time were significantly lower in patients than in controls (p= 0.04 or less). Plasma aldosterone and noradrenaline levels were not significantly different at every sampling time in the two groups. No significant differences in daily renal sodium excretion were found. However, urinary cyclic guanosine monophosphate excretion was significantly higher in patients than in controls (p<0.01).

CONCLUSIONS

The initial abnormalities of sodium metabolism in cirrhosis might be characterized by blunted renal responsiveness to natriuretic peptides. The results of the study also provide indirect evidence that the impairment is mainly located at postreceptor levels of signal transduction pathway to the peptides, if the activation of antinatriuretic factors other than renin-angiotensin or sympathoadrenergic systems does not play a role.

Hepatorenal failure

Since the description of HRS more than 100 years ago, significant advances have been made in understanding the pathophysiology of HRS and in the management of these patients. There is now a therapeutic armamentarium: medical (ornipressin plus plasma volume expansion), radiographic (TIPS shunt), and surgical (liver transplantation). The diagnosis of HRS is no longer synonymous with a death sentence; instead, it is a therapeutic challenge, and a coordinated approach by intensivists, hepatologists, nephrologists, interventional radiologists, and transplant surgeons is needed to continue to improve the prognosis of cirrhotic patients presenting with HRS. Increased understanding of HRS will allow preventative rather than therapeutic measures to be used. As in all fields of medicine, these advances will come only with innovative clinical investigation.

Pattern of plasma cyclic nucleotides and related hormones in liver cirrhosis and hepatocellular carcinoma

To evaluate the pattern of plasma cyclic adenosine 3',5'-monophosphate, cyclic guanosine 3',5'-monophosphate, atrial natriuretic factor and glucagon levels in different stages of chronic liver diseases, we measured these variables in 20 normal subjects, 25 patients with genetic hemochromatosis, associated with liver cirrhosis in 19 cases and not in six, eight patients with compensated and 15 with decompensated alcoholic or posthepatitic cirrhosis, and 12 with hepatocellular carcinoma. All variables were within the normal range in non-cirrhotic hemochromatotic patients. Cyclic adenosine 3',5'-monophosphate levels were within the normal range (9.5-15.7 nmol/l) in hemochromatotic cirrhotics and elevated in other patients. Cyclic guanosine 3',5'-monophosphate, atrial natriuretic factor and glucagon were above the normal ranges (1.92-5.91 nmol/l, 8.8-62.7 ng/l, and 39-165 ng/l, respectively) in most patients with cirrhosis both with and without hemochromatosis and in most individuals with hepatocellular carcinoma. Cyclic guanosine 3',5'-monophosphate correlated with atrial natriuretic factor in the former groups but not in the latter. These findings indicate that glucagon and atrial natriuretic factor hypersecretion is an early event in cirrhosis, regardless of its etiology. In hepatocellular carcinoma, the underlying cirrhosis may account for most hormonal and metabolic changes although cyclic guanosine 3',5'-monophosphate increases could also be due to the neoplastic process per se.

Effects of long-term administration of octreotide on sodium retention and atrial natriuretic peptide in carbon tetrachloride-induced cirrhotic rats

BACKGROUND/AIMS

To realize the roles of peripheral vasodilatation and atrial natriuretic peptide in the formation of cirrhotic ascites, the effects of long-term administration of octreotide on carbon tetrachloride-induced cirrhotic rats were evaluated.

METHODS

Urine sodium excretion, hemodynamics, plasma atrial natriuretic peptide levels, renin activities and aldosterone concentrations were compared between cirrhotic and control rats (protocol 1); and between octreotide- (65 micrograms/kg, twice daily for 10 days, subcutaneously) and placebo-treated (5% dextrose) cirrhotic rats (protocol 2). In an in vitro experiment, right atrial tissue of cirrhotic rats was incubated with different concentrations of octreotide to evaluate the release of atrial natriuretic peptide (protocol 3).

RESULTS

Cirrhotic rats had significantly lower urine sodium excretion and systemic vascular resistance, and significantly higher plasma atrial natriuretic peptide levels, renin activities and aldosterone concentrations than control rats. Compared with placebo-treated cirrhotic rats, octreotide caused increased urine sodium excretion (-10 +/- 4% vs. 13 +/- 8% from baseline values, p < 0.05) and systemic vascular resistance (2.6 +/- 0.1 vs. 3.3 +/- 0.3 mmHg.min.100 g.ml-1, p < 0.05); and decreased plasma atrial natriuretic peptide levels (166.7 +/- 24.8 vs. 234.0 +/- 19.2 pg/ ml, p < 0.05), renin activities (2.45 +/- 0.49 vs. 4.36 +/- 0.53 ng.ml-1.h-1, p < 0.01) and aldosterone concentrations (290.2 +/- 40.0 vs. 483.3 +/- 82.6 pg/ml, p < 0.05). In the in vitro experiment, right atrial release of atrial natriuretic peptide of cirrhotic rats was not significantly changed when incubated with different concentrations of octreotide.

CONCLUSIONS

Octreotide ameliorates renal sodium retention and suppresses plasma levels of atrial natriuretic peptide of ascitic cirrhotic rats with a novel mechanism via, at least partly, the modification of peripheral vascular resistance.

Hemodynamic and renal effects of ascites apheresis, concentration and reinfusion in advanced cirrhosis

BACKGROUND/AIMS

We studied the effects of ascites apheresis, concentration and reinfusion, a new form of treatment for tense or refractory ascites, on systemic hemodynamics and renal function.

METHODS

Twelve patients with advanced cirrhosis (two belonging to Child-Pugh's class B and the remainder to class C) were monitored. They were evaluated under baseline conditions, just after the treatment, and 24 and 48 h after baseline assessment. In addition to systemic hemodynamics--as evaluated by Doppler echocardiography--and renal function, indirect markers of effective volemia, such as atrial natriuretic factor, plasma renin activity and aldosterone concentration, and plasma norepinephrine were also measured.

RESULTS

The technique led to significant changes in systemic hemodynamics, such as an increase in stroke volume and cardiac output. However, due to a striking reduction in peripheral vascular resistance, mean arterial pressure also declined. The hemodynamic changes were associated with a parallel increase in atrial natriuretic factor. Despite the reduction in arterial pressure, plasma renin activity also significantly declined, while plasma norepinephrine did not undergo significant changes. Although an improvement in glomerular filtration rate and renal sodium excretion occurred, neither change reached statistical significance. All the hemodynamic, renal and neuro-humoral changes described above subsided almost entirely after 48 h, when no significant changes with respect to baseline values were any longer detectable with the exception of a slight reduction in mean arterial pressure.

CONCLUSIONS

In advanced cirrhosis ascites apheresis, concentration and reinfusion enhance central volemia, but an exaggerated peripheral vasodilation largely wastes the potential favourable effect on arterial volemia. As a result, no significant improvement in renal perfusion and sodium excretion can ensue.

Blunted natriuretic response to human urine extracts with Na+,K(+)-ATPase inhibiting activity in experimental cirrhosis

Human urine and plasma extracts contain a material that inhibits the enzyme Na+,K(+)-ATPase (the endogenous sodium pump) and produces natriuresis in the bioassay animal. This endogenous sodium pump inhibitor(s), also known as digitalis-like factor, is thought to be involved in sodium and extracellular fluid volume homeostasis. Increased urine and plasma sodium pump inhibiting activity have been reported in patients with cirrhosis and sodium retention. The aim of the study was to assess the renal response to i.v. administration (0.2 ml/min per kg bw for 10 min) of a human urine extract containing sodium pump inhibiting activity (28.5 nmol equivalent ouabain/ml) in eight conscious rats with cirrhosis and ascites and eight control rats. Baseline urinary excretion of Na+,K(+)-ATPase inhibiting activity was significantly higher in cirrhotic rats with ascites than in control rats (235 +/- 40 vs 91 +/- 16; p < 0.01). Human urine extract induced a significant (p < 0.05) increase in glomerular filtration rate in control (3.2 +/- 0.4 to 4.2 +/- 0.5 ml/min) and cirrhotic rats (3.0 +/- 0.3 to 4.0 +/- 0.5 ml/min). In control rats it also increased urinary sodium excretion (1.47 +/- 0.22 to 2.43 +/- 0.5 microEq/min, p < 0.01) and fractional sodium excretion (0.29 +/- 0.01 to 0.43 +/- 0.04%, p < 0.025). In contrast, in cirrhotic rats with ascites neither sodium excretion nor fractional sodium excretion was significantly affected. No changes were observed in plasma aldosterone and atrial natriuretic peptide concentrations in either group. These data suggest that in cirrhosis there is a renal resistance to the natriuretic effect of endogenous sodium pump inhibitor(s).

Time course of circulatory and humoral effects of rapid total paracentesis in cirrhotic patients with tense, refractory ascites

BACKGROUND/AIMS

Tense ascites of cirrhosis can be treated with total paracentesis; however, the short-term effects of this procedure are poorly defined.

METHODS

The circulatory and humoral changes induced by total paracentesis (250 mL/min) were studied in 12 cirrhotics with tense, refractory ascites. Data were collected before, during, and after paracentesis and 24 hours later (after albumin infusion). Hormonal parameters were recorded again 48 hours and 6 days thereafter.

RESULTS

Paracentesis (10.7 +/- 4.4 L; 64 +/- 20 minutes) caused marked reduction of intra-abdominal, intrathoracic, right atrial, and pulmonary pressures. Heart rate did not change. Cardiac output and heart volumes increased. Systemic vascular resistances and mean arterial pressure slightly decreased. Baseline plasma renin and aldosterone levels were markedly increased; a reduction was already evident during paracentesis with the lowest values at the end of the procedure. All changes were maintained 24 hours later. Hormones regained baseline levels 6 days later.

CONCLUSIONS

Rapid total paracentesis is accompanied by marked cardiovascular and humoral changes. Some of these changes can be explained by mechanical factors that are directly or indirectly related to the relief of abdominal pressure. However, other changes (systemic vasodilatation, humoral deactivation) have a non-mechanical nature and may depend on reflexes originating from cardiac volume receptor stimulation. Most changes may beneficially (albeit transiently) influence the cardiovascular system of cirrhotic patients with tense ascites.

Ascites apheresis, concentration and reinfusion for the treatment of massive or refractory ascites in cirrhosis

A new method for ascites recirculation, consisting of a cellulose diacetate filter to remove substances with molecular weight > or = 300,000, cell debris and bacteria, followed by the concentration of ascitic fluid prior to i.v. infusion, was used 24 times in 19 patients with cirrhosis and massive or refractory ascites. The amount of ascites removed was 7.67 +/- 0.49 l, which was reduced to 407 +/- 37 ml. The procedure took 367 +/- 22 min to complete. No statistically significant changes in liver function tests, coagulative parameters, platelet count or natremia were found. The activity of coagulation and fibrinolytic systems was further assessed in six patients. No changes suggesting an activation of intravascular coagulation and/or primary fibrinolysis were disclosed. An asymptomatic fall in mean arterial pressure (from 88.6 +/- 2.6 to 80.3 +/- 3.0 mmHg; p = 0.02) occurred after paracentesis and was still present 48 h after ascites reinfusion. Plasma renin activity significantly decreased at the end of the procedure, but was not associated with a proportional reduction of plasma aldosterone concentrations. Both variables returned to baseline values 48 h later. A significant increase in the glomerular filtration rate occurred just after the end of the procedure (from 50.4 +/- 9.1 to 73.1 +/- 23.5 ml/min; p < 0.05) and subsided 48 h later. In contrast, no significant changes in diuresis and renal sodium excretion were found. Complications due to volume overload and sepsis did not occur; in one case, spontaneous bacterial peritonitis developed 3 days after the procedure.(ABSTRACT TRUNCATED AT 250 WORDS)

Disposal of atrial natriuretic factor (ANF99-126) in patients with cirrhosis: effect of beta-adrenergic blockade

To test a possible effect of blood flow change on disposal of atrial natriuretic factor: ANF99-126 (ANF), we determined renal, azygos, hepatic and cubital venous, and arterial plasma concentrations of ANF in 18 patients with cirrhosis before and after ingestion of propranolol 80 mg. Arterial ANF was similar to that of controls (9.4 vs. 10.9 pmol l-1, NS) and was positively correlated to cardiac output (r = 0.49, p < 0.02) and to right atrial pressure (r = 0.44, p < 0.01). All the vascular beds examined extracted ANF significantly. The renal (n = 17), hepato-enteric (n = 16), and splanchnic superior collateral (azygos) beds (n = 13) had significantly higher extraction ratios (0.34-0.39) than that observed in the cubital vein (0.24, n = 15, p < 0.05). Arterial ANF showed no significant change (9.6-11.0 pmol l-1, NS) after reduction of cardiac output (-25%, p < 0.001) by propranolol. Only insignificant changes in ANF extraction and a small decrease in azygos and hepato-enteric clearance occurred during beta-adrenergic blockade. Our results show a substantial extraction of ANF in the kidney, in the splanchnic bed drained through superior portosystemic collaterals, and in the hepato-enteric bed. Only minor effects on ANF extraction were observed after reduction of the blood flow with propranolol.

The role of atrial natriuretic peptide (ANP) in chronic liver disease

The role of atrial natriuretic peptide (ANP) and potential defects of ANP in liver disease are reviewed. Patients with cirrhosis of the liver show no decrease of ANP plasma concentrations nor changes in the pattern of ANP immunoreactivity nor changes of splanchnic ANP clearance. The renal effects of exogenously administered as well as endogenously released ANP are blunted in cirrhosis, in particular in patients with ascites. This seems due to increased activity of sodium-retaining hormonal systems and changes of the renal ANP receptor status. Pharmacological inhibition of ANP-degradation or clearance may yield therapeutic potential.

Concentrated ascitic fluid reinfusion after cascade filtration in tense ascites

A new method for concentrated ascitic fluid reinfusion using a double ultrafiltration device is reported as 22 procedures in 20 cirrhotic patients (6 females, 14 males; median age 55 years, range 33-69) with tense, refractory ascites. Eight of the 20 patients had elevated creatinine levels. The mean time for each procedure was 189 +/- 82 min, during which a mean of 7.7 liters (1.3-13.3) of ultrafiltered ascitic fluid was removed and 613 ml (140-1700) of concentrated ascitic fluid rich in albumin (mean: 60 g, range 14-175) was reinfused. The procedure resulted in a mean weight loss of 8.1 kg (2.2-14.0) and a mean increase of 163 ml in urine output (24 hr). A reduction in the serum creatinine level (P < 0.05) and an increase in the plasma atrial natriuretic factor level (P < 0.02) 24 hr after reinfusion, while no changes in serum albumin, plasma and urinary electrolytes, plasma renin activity, aldosterone, and antidiuretic hormone levels were noted. Although minor evidence for a disturbance in coagulation was observed, there were no episodes of clinical bleeding. Four patients (20%) had transient chills or fever. Based upon this experience, it can be concluded that reinfusion of cascade filtered and concentrated ascitic fluid is a rapid, safe, and effective treatment for patients with tense ascites; it appears to have less side effects than more traditional methods and importantly does not require administration of heterologous plasma derivatives.

Variability of atrial natriuretic peptide plasma levels in ascitic cirrhotics: pathophysiological and clinical implications

Ascitic cirrhotic patients are a heterogenous population with respect to factors that may affect plasma human atrial natriuretic peptide levels (such as degree of plasma volume and plasma levels of angiotensin II, vasopressin and norepinephrine). Thus the proven variability of plasma human atrial natriuretic peptide values in ascitic cirrhotic patients may be due also to the selection of patients, not only to the study conditions. The response to standardized stepped-care medical treatment of ascites makes it possible to characterize ascitic cirrhotic patients with different patterns of renal sodium excretion, intrarenal sodium handling, plasma renin activity, plasma aldosterone and thus, probably, effective circulating volume. Consequently, we evaluated human atrial natriuretic peptide plasma levels in controls (n = 23), in ascitic cirrhotic patients who underwent spontaneous diuresis (group A, n = 7) and in cirrhotic patients who required diuretic treatment (group B, n = 44). The last group was then divided into two subgroups. Subgroup B-R (n = 25) included patients who responded to spironolactone alone, whereas subgroup B-NR (n = 19) included patients who did not respond to 500 mg/day spironolactone. All patients were maintained on identical normocaloric restricted sodium intake (80 mEq/day) throughout the study. Ascitic cirrhotic patients, as a whole, had higher values of human atrial natriuretic peptide than did controls (70.8 +/- 46.6 pg/ml vs. 41.7 +/- 16.3 pg/ml, p < 0.025). No difference was found in human atrial natriuretic peptide/plasma renin activity between the two groups (87 +/- 160 pg/ng/hr vs. 44 +/- 73 pg/ng/hr, p = NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Estimated central blood volume in cirrhosis: relationship to sympathetic nervous activity, beta-adrenergic blockade and atrial natriuretic factor

The estimated central blood volume (i.e., blood volume in the heart cavities, lungs and central arterial tree) was determined by multiplying cardiac output by circulatory mean transit time in 19 patients with cirrhosis and compared with sympathetic nervous activity and circulating level of atrial natriuretic factor. Arterial norepinephrine level, an index of overall sympathetic nervous activity (3.08 nmol/L in patients vs. 1.36 nmol/L in controls; p < 0.01) was negatively correlated (r = -0.54, p < 0.01) with estimated central blood volume (mean = 23 ml/kg in patients vs. 27 ml/kg in controls; p < 0.05). Similarly, renal venous norepinephrine level (an index of renal sympathetic tone; 4.26 nmol/L in patients vs. 1.78 nmol/L in controls; p < 0.01) was inversely correlated with estimated central blood volume (r = -0.53, n = 18, p < 0.02). No significant correlation could be established between arterial atrial natriuretic factor level (8.9 pmol/L in patients vs. 9.6 pmol/L in controls; not significant) and estimated central blood volume. Hemodynamic values were subsequently modified with oral propranolol (80 mg). During beta-adrenergic blockade, the mean estimated central blood volume was not altered significantly, except in six patients who exhibited decreases in mean arterial blood pressure (85 to 69 mm Hg; n = 6) and decreases in mean estimated central blood volume (23.2 to 20.6 ml/kg; n = 6, p < 0.05). Slight increases were observed in mean right atrial pressure (2.2 to 3.7 mm Hg; n = 14, p < 0.05); this change was positively correlated with the change in estimated central blood volume (r = 0.44, n = 14, p = 0.06).(ABSTRACT TRUNCATED AT 250 WORDS)

Renal effects in cirrhotic patients with avid sodium retention of atrial natriuretic factor injection during norepinephrine infusion

The administration of atrial natriuretic factor to patients with cirrhosis, and avid sodium retention causes marked hypotension and blunted kidney responses. To evaluate whether the unresponsiveness of the kidney is caused by a fall in mean blood pressure below a critical value for the renal blood perfusion pressure (80 mm Hg), we studied nine such patients and compared the effects of synthetic atrial natriuretic factor alone (1 micrograms/kg as a bolus) with those of an atrial natriuretic factor combination with infused norepinephrine titrated to raise baseline blood pressure by 15 to 20 mm Hg (182 to 625 ng/kg/min). The administration of atrial natriuretic factor during norepinephrine infusion caused a fall in mean blood pressure to values not less than 80 mm Hg in eight of nine patients, with a slight natriuresis (greater than 5 mumol/min) in five patients but no changes in the other four. The mean urinary sodium output was markedly lower than that previously observed after atrial natriuretic factor injection into normal subjects and into cirrhotic patients without avid sodium retention. Unlike sodium excretion, urine flow rate and free water clearance (which were not affected by atrial natriuretic factor alone) were markedly improved by the coadministration of norepinephrine and atrial natriuretic factor. In four additional patients we studied the urinary electrolyte excretion during a low-dose infusion of atrial natriuretic factor (20 ng/kg/min) to which an infusion of norepinephrine titrated to maintain blood pressure over 80 mm Hg was added. In only one of these four patients urinary sodium output consistently increased during atrial natriuretic factor infusion, and the output increased even more when norepinephrine was added.(ABSTRACT TRUNCATED AT 250 WORDS)

Atrial natriuretic factor: its (patho)physiological significance in humans

The first human studies using relatively high-doses of ANF revealed similar effects as observed in the preceding animal reports, including effects on systemic vasculature (blood pressure fall, decrease in intravascular volume), renal vasculature (rise in GFR, fall in renal blood flow), renal electrolyte excretion (rises in many electrolytes), and changes in release of a number of different hormones. Whether all these changes are the result of direct ANF effects or secondary to a (single) primary event of the hormone remains to be determined. Certainly, it has been proven that more physiological doses of ANF fail to induce short-term changes in many of these parameters leaving only a rise in hematocrit, natriuresis and an inhibition of the RAAS as important detectable ANF effects in humans. This leads us to hypothesize that ANF is a "natriuretic" hormone with physiological significance. The primary function in humans is to regulate sodium homeostasis in response to changes in intravascular volume (cardiac atrial stretch). Induction of excess renal sodium excretion and extracellular volume shift appear to be the effector mechanisms. The exact mechanism of the natriuresis in humans still needs to be resolved. It appears however, that possibly a small rise in GFR, a reduction in proximal and distal tubular sodium reabsorption, as well as an ensuing medullary washout, are of importance. The pathophysiological role of ANF in human disease is unclear. One may find elevated plasma irANF levels and/or decreased responses to exogenous ANF in some disease states. Whether these findings are secondary to the disease state rather than the cause of the disease remains to be resolved. Therapeutic applications for ANF, or drugs that intervene in its production or receptor-binding, seem to be multiple. Most important could be the antihypertensive effect, although areas such as congestive heart failure, renal failure, liver cirrhosis and the nephrotic syndrome cannot be excluded. Although the data that have been gathered to date allowed us to draw some careful conclusions as to the (patho)physiological role of ANF, the exact place of ANF in sodium homeostatic control must still be better defined. To achieve this, we will need more carefully designed low-dose ANF infusion, as well as ANF-breakdown inhibitor studies. Even more promising, however, is the potential area of studies open to us when ANF-receptor (ant)agonists become available for human use.

Ornipressin in the treatment of functional renal failure in decompensated liver cirrhosis. Effects on renal hemodynamics and atrial natriuretic factor

In 11 patients with decompensated cirrhosis and deteriorating renal function, the effect of the vasoconstrictor substance 8-ornithin vasopressin (ornipressin; POR 8; Sandoz, Basel, Switzerland) on renal function, hemodynamic parameters, and humoral mediators was studied. Ornipressin was infused at a dose of 6 IU/h over a period of 4 hours. During ornipressin infusion an improvement of renal function was achieved as indicated by significant increases in inulin clearance (+65%), paraaminohippuric acid clearance (+49%), urine volume (+45%), sodium excretion (+259%), and fractional elimination of sodium (+130%). The hyperdynamic circulation was reversed to a nearly normal circulatory state. The increase in systemic vascular resistance (+60%) coincided with a decrease of a previously elevated renal vascular resistance (-27%) and increase in renal blood flow (+44%). The renal fraction of the cardiac output increased from 2.3% to 4.7% (P less than 0.05). A decline of the elevated plasma levels of noradrenaline (2.08-1.13 ng/mL; P less than 0.01) and renin activity (27.6-14.2 ng.mL-1.h-1; P less than 0.01) was achieved. The plasma concentration of the atrial natriuretic factor increased in most of the patients, but slightly decreased in 3 patients. The decrease of renal vascular resistance and the increase of renal blood flow and of the renal fraction of cardiac output play a key role in the beneficial effect of ornipressin on renal failure. These changes develop by an increase in mean arterial pressure, the reduction of the sympathetic activity, and probably of an extenuation of the splanchnic vasodilation. A significant contribution of atrial natriuretic factor is less likely. The present findings implicate that treatment with ornipressin represents an alternative approach to the management of functional renal failure in advanced liver cirrhosis.

Effect of intrathoracic pressure on plasma arginine vasopressin levels

Abdominal distention during pneumoperitoneum results in a marked increase in plasma arginine vasopressin levels, which has been ascribed to an increase in intrathoracic pressure. Because of this relationship, tense ascites could contribute to nonosmotic release of antidiuretic hormone, to the development of hyponatremia, and eventually to further ascites formation. The effect of pneumoperitoneum, thoracocentesis, and paracentesis on plasma arginine vasopressin levels was studied in three groups of patients, and the mechanism by which these maneuvers may induce these changes was investigated. Patients with pleural effusion, pneumothorax, or ascites showed a significant increase in plasma arginine vasopressin levels, and thoracocentesis or paracentesis resulted in a decrease in these levels. Plasma vasopressin levels increased significantly during pneumoperitoneum, as did intrathoracic and atrial pressures; the atrial transmural pressure gradient declined. However, no changes in plasma levels of norepinephrine, aldosterone, and renin activity were observed during pneumoperitoneum. Changes in plasma arginine vasopressin levels correlated with the changes in intrathoracic and atrial pressures and transmural pressure gradient. The authors conclude that increased intrathoracic pressure is associated with an increase in plasma arginine vasopressin levels and propose that ascites could be a factor promoting vasopressin release by acting on intrathoracic volume receptors in decompensated cirrhotics.

Randomized comparative study of hemaccel vs. albumin infusion after total paracentesis in cirrhotic patients with refractory ascites

Fifty-four cirrhotic patients with refractory ascites were treated with one-session large-volume paracentesis and randomly assigned to two groups. The first group was infused with human albumin, and the second group was infused with hemaccel at doses with comparable oncotic power. The two groups were compared for incidence of complications, recurrence of massive ascites after hospital dismissal and survival rate. The incidence of complications traditionally related to paracentesis, the probability of requiring readmission to the hospital for ascites (p = 0.48) and the probability of survival after entry into the study (p = 0.85) were the same for the two groups. A multivariate analysis of 16 parameters, including treatment modality, identified absolute unresponsiveness to diuretics as the only independent predictor of mortality. These results indicate that hemaccel infusion may safely replace albumin infusion after total paracentesis for cirrhotic patients with refractory ascites.

Pathophysiology and clinical basis of prevention and treatment of complications of chronic liver disease

Chronic liver failure is characterized by the appearance of jaundice, ascites, encephalopathy and/or gastrointestinal bleeding. Acute episodes of hepatic decompensation are frequently precipitated by additional events, e.g. septicaemia, diuretic therapy or excessive protein intake. Identification, correction and treatment of these precipitating factors are first steps in the management of chronic liver failure. Nutritional support is important in the treatment of cirrhotic patients, because malnutrition is one of the major determinants of patient outcome. Management of encephalopathy reduces the appearance of gut-derived nitrogenous toxins and corrects imbalances in amino acid metabolism. Treatment of ascites is salt restriction supported by gentle and incremental administration of diuretics. Ursodesoxycholic acid has become a new and promising modality in the management of cholestatic liver diseases. If conservative therapy fails to recompensate liver function, liver transplantation may be indicated.