Renal sodium retention during upright posture in preascitic cirrhosis

Autonomic neuropathy in extra-hepatic portal vein thrombosis: evidence for impaired autonomic reflex arc

BACKGROUND/AIMS

Autonomic dysfunction is common in cirrhosis, and may be associated with increased mortality and hyperdynamic circulatory changes. Our aim was to investigate whether autonomic disturbances occur in extrahepatic portal vein thrombosis and their correlation with hemodynamic abnormalities.

PATIENTS AND METHODS

Heart rate variation in response to standing, deep breathing, and Valsalva maneuver, and blood pressure response to sustained handgrip and to standing, were studied in 16 subjects with portal vein thrombosis (10 males, 30.8+/-2.8 years: mean+/-SE), 12 with cirrhosis (7 males, 52+/-2.3 years), and 10 healthy controls (7 males, 30.8+/-3.0 years). Supine resting, and 10- and 30-min standing epinephrine and norepinephrine levels were measured and results correlated with cardiac output.

RESULTS

Autonomic dysfunction occurred in 62% of portal vein thrombosis and 75% of cirrhosis subjects, but in no controls (p<0.02). Similarly, postural hypotension occurred in portal vein thrombosis (-10.25+/-0.65 mmHg, p=0.003) and cirrhosis (-7.42+/-0.82 mmHg, p=0.007) but not in controls. All groups had similar baseline epinephrine and norepinephrine concentrations. Epinephrine increased significantly in controls (45%, p<0.01 and 49%, p<0.02) after 10 of 30 min standing but not in the portal vein thrombosis or the cirrhotic group, and norepinephrine increased after 10 and 30 min standing in cirrhotics (128%, p<0.004 and 130%, p<0.008) and controls (129%, p<0.002 and 116%, p<0.004), but not portal vein thrombosis (34.5% and 39%, NS vs baseline). Portal vein thrombosis and cirrhosis groups had increased cardiac output (4441+/-509 and 3262+/-292) vs controls (1763+/-212 ml/min/m2, p<0.002), but there was no correlation with autonomic neuropathy or with catecholamine levels.

CONCLUSIONS

Autonomic dysfunction and impaired catecholamine response to orthostatic stress occur commonly in portal vein thrombosis and suggest an impairment of the autonomic reflex arc, but changes do not correlate with hemodynamic abnormalities.

Plasma endothelin-1 and -3 in cirrhosis: relationship with systemic hemodynamics, renal function and neurohumoral systems

BACKGROUND/AIMS

The postural change from upright to supine is a physiological maneuvre which increases central blood volume. This model was used to investigate the effects of changes in effective volemia on plasma endothelin-1 and -3 concentrations in cirrhosis.

METHODS

Plasma endothelin concentrations, measured by radio-immunoassay, were determined in 20 patients with cirrhosis, 10 of whom has ascites, and nine healthy control subjects, in the upright posture and 30, 60 and 120 min after the assumption of the supine position.

RESULTS

In the upright posture, endothelin-1 was 8.9 +/- 0.4 pg/ml and endothelin-3 3.7 +/- 0.6 (mean +/- SEM) pg/ml in control subjects. Endothelin-1 was increased only in patients with ascites (12.7 +/- 1.4 pg/ml, p < 0.05; patients without ascites: 9.7 +/- 0.7 pg/ml), while endothelin-3 was elevated in both patients with and without ascites (8.0 +/- 1.5 pg/ml, p < 0.01; 5.9 +/- 0.5 pg/ml, p = 0.01, respectively). In the supine position, no significant changes in endothelin-1 or -3 occurred either in patients with ascites or in controls throughout the observation period, while a reduction in endothelin-3 was found in compensated patients after 30 and 60 min. In patients, we found negative correlations between endothelin-3, but not endothelin-1, and mean arterial pressure, both in upright (r = -0.59; p < 0.01) and supine (r = -0.56; p = 0.01) positions, atrial natriuretic factor (r = 0.50; p < 0.05) and plasma renin activity (r = 0.67; p = 0.001) in the supine position alone. In patients with ascites, endothelin-1 was inversely correlated with both glomerular filtration rate (upright: r = -0.62; p = 0.06; supine: r = -0.71, p < 0.05) and renal sodium excretion (upright: r = -0.82; p < 0.01; supine: r = -0.88; p < 0.001).

CONCLUSIONS

Plasma endothelin-1 and -3 were increased in cirrhosis with ascites, while, in pre-ascitic cirrhosis, only endothelin-3 was increased in the upright posture. Although increased endothelin-3 was associated with features suggesting a reduced effective volemia, it is likely that other mechanisms than hypovolemia were mainly responsible for high plasma endothelin levels. Increased endothelin production may play a role in circulatory and renal function abnormalities of advanced cirrhosis.

Effect of volume expansion on systemic hemodynamics and central and arterial blood volume in cirrhosis

BACKGROUND & AIMS

Systemic vasodilatation in cirrhosis may lead to hemodynamic alterations with reduced effective blood volume and decreased arterial blood pressure. This study investigates the response of acute volume expansion on hemodynamics and regional blood volumes in patients with cirrhosis and in controls.

METHODS

Thirty-nine patients with cirrhosis (12 patients with Child-Turcotte class A, 14 with class B, and 13 with class C) and 6 controls were studied. During hepatic vein catheterization, cardiac output, systemic vascular resistance, central and arterial blood volume, noncentral blood volume, and arterial pressure were determined before and during a volume expansion induced by infusion of a hyperosmotic galactose solution.

RESULTS

During volume expansion, the central and arterial blood volume increased significantly in patients with class A and controls, whereas no significant change was found in patients with either class B or class C. Conversely, the noncentral blood volume increased in patients with class B and C. In both patients and controls, the cardiac output increased and the systemic vascular resistance decreased, whereas the mean arterial blood pressure did not change significantly.

CONCLUSIONS

Only in mild cirrhosis is the effective blood volume able to increase in response to volume expansion. Our results are consistent with the peripheral vasodilatation hypothesis and the circulatory hyporeactivity occurring in advanced cirrhosis.

Effect of upright posture and physical exercise on endogenous neurohormonal systems in cirrhotic patients with sodium retention and normal supine plasma renin, aldosterone, and norepinephrine levels

It is well known that sodium retention occurs in a significant proportion of patients with cirrhosis despite normal supine plasma levels of renin, aldosterone (ALDO), and norepinephrine (NE). The current study was performed to assess whether this subset of patients also present normal activity of the renin-aldosterone and sympathetic nervous systems during upright posture in sitting position and moderate physical exercise. Nine healthy controls, 14 patients with compensated cirrhosis and 10 patients with cirrhosis, ascites, sodium retention, and normal supine plasma renin activity (PRA) and ALDO and NE concentration were sequentially studied after 60 minutes in supine rest, 30 minutes in sitting position, and 30 minutes of cycloergometric exercise (3-METs). Sitting position and exercise were associated with similar stimulation of the renin-aldosterone and sympathetic nervous systems in the three groups of subjects. Consequently, cirrhotic patients with ascites showed values of PRA and plasma concentration of ALDO and NE similar to healthy subjects and patients with compensated cirrhosis during supine rest (renin: 1.4 +/- 0.3, 0.8 +/- 0.2, and 0.8 +/- 0.3 ng/mL; aldosterone: 24.3 +/- 4.7, 20.2 +/- 3.9 and 21.4 +/- 3.4 ng/dL; norepinephrine: 252 +/- 23, 250 +/- 16, and 255 +/- 23 pg/mL), sitting position (renin: 2.1 +/- 0.5, 1.1 +/- 0.3, and 1.6 +/- 0.4; aldosterone: 32.2 +/- 7.3, 23.7 +/- 5.3, and 26.2 +/- 4.5; norepinephrine: 356 +/- 38, 401 +/- 63, and 420 +/- 35), and exercise (renin: 2.9 +/- 0.8, 1.6 +/- 0.4, and 2.2 +/- 0.5; aldosterone: 43 +/- 6.4, 34.9 +/- 8.5, and 38.2 +/- 5.3; norepinephrine: 481 +/- 35, 499 +/- 54, and 534 +/- 48).(ABSTRACT TRUNCATED AT 250 WORDS)

Noninvasive 24-hour ambulatory arterial blood pressure monitoring in cirrhosis

Cirrhotic patients have disturbed systemic hemodynamics with reduced arterial blood pressure, but this has not been investigated during daily activity and sleep. Systolic (SBP), diastolic (DBP), and mean arterial blood pressure (MAP), and heart rate (HR) were measured by an automatic ambulant device for monitoring blood pressure in 35 patients with cirrhosis and 35 healthy matched controls. During the daytime, SBP, DBP, and MAP were significantly lower in the patients than in the controls (median 118 vs. 127; 70 vs. 78; 86 vs. 94 mm Hg, P < .0001 to P < .05). The nighttime blood pressures were almost similar in the two groups (108 vs. 110; 65 vs. 67; 78 vs. 82 mm Hg, NS). Conversely, HR was significantly higher in the patients both in the daytime (86 vs. 72/min, P < .0001) and at night (80 vs. 64/min, P < .0001). Consequently, the reduction in blood pressure and HR from daytime to nighttime was significantly lower in the patients than in the controls (P < .0001 to P < .01). Multiple regression analysis showed HR, serum albumin, serum sodium, and clotting factors 2, 7, and 10 as significant independent predictors of SBP in cirrhosis. In conclusion, cirrhotic patients have elevated HR, but surprisingly normal arterial blood pressure during the nighttime, and the circadian variation in blood pressure and HR is diminished, probably because of an almost unaltered cardiac output during the 24 hours. These results may reflect a major defect in the ability of optimal regulation of blood pressure in cirrhotic patients.

Pattern of sodium handling and its consequences in patients with preascitic cirrhosis

BACKGROUND/AIMS

The initial abnormalities in the renal sodium handling in patients with cirrhosis before developing ascites remain unknown. The aim of this study is to further characterize sodium metabolism and the effects of sodium loading in preascitic cirrhosis.

METHODS

Eight male, preascitic patients with cirrhosis and 6 volunteers had their daily urinary sodium excretion level measured while on a strictly metabolically controlled diet, first consisting of 20 mmol then of 200 mmol sodium per day each for 7 days. Central blood volume, plasma norepinephrine, and atrial natriuretic factor levels were measured during each diet.

RESULTS

Preascitic patients with cirrhosis had significantly less daily urinary sodium excretion on both diets. Volume expansion in the patients with cirrhosis was indicated by significantly greater weight gain and higher atrial natriuretic factor levels for each diet. Patients with cirrhosis had central blood volume expansion (1725 +/- 54 mL/m2) compared with controls (1495 +/- 81 mL/m2; P = 0.03) on a low-sodium diet. This increased significantly in the controls (1864 +/- 164 mL/m2; P = 0.04) on a high-sodium diet, associated with suppression of plasma norepinephrine, but not in the patients with cirrhosis (1679 +/- 107 mL/m2; P > 0.05).

CONCLUSIONS

Failure of further central blood volume expansion in the patients with cirrhosis on high-sodium diet in the presence of significant weight gain suggests maldistribution away from the effective arterial blood volume. This study provides further reasons why preascitic patients with cirrhosis might benefit from sodium restriction.

Renal sodium handling in cirrhosis with ascites: mechanisms of impaired natriuretic response to reclining

We recently showed that patients with compensated cirrhosis can dispose of their fluid overload while reclining. In contrast, patients with ascites fail to develop supine-induced natriuresis. To assess the effect of reclining on renal sodium handling in patients with advanced cirrhosis and the mechanisms blunting natriuresis in this situation, renal function and plasma concentrations of atrial natriuretic factor, aldosterone and norepinephrine were evaluated in 10 nonazotemic patients with cirrhosis and ascites and 10 healthy controls standing for 2 h and reclining for 2 h. While standing, all patients showed marked sodium retention and significantly elevated plasma atrial natriuretic factor levels, aldosterone and norepinephrine. Glomerular filtration rate did not differ from healthy controls. The reclining increased renal sodium excretion in both groups, but this change was far less marked in patients; natriuresis only rose to the control range in two of them. An increase in atrial natriuretic factor and a depression of plasma aldosterone and norepinephrine was seen in both controls and patients. In the latter, despite the greater change in atrial natriuretic factor and aldosterone, the aldosterone to atrial natriuretic factor ratio, which was inversely correlated with natriuresis during both standing and reclining remained significantly elevated. In the two patients who achieved normal natriuresis during reclining, reclining was associated with both the normalization of the aldosterone/atrial natriuretic factor ratio, and with an increase in glomerular filtration rate. The supine-induced increase in atrial natriuretic factor was not only preserved but was even enhanced in cirrhosis with ascites.(ABSTRACT TRUNCATED AT 250 WORDS)

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.