Hepatorenal syndrome

Diagnostic value of serum cystatin C for evaluation of hepatorenal syndrome

BACKGROUND

The evaluation of renal function in patients with decompensated cirrhosis is important for prognosis, dosage assessment of potentially nephrotoxic drugs and recognition of changes in glomerular filtration rate (GFR) to decide paracentesis and diuretic therapy. Patients with many different disorders of hepatic function can present with various abnormalities of renal function in the absence of other known causes of renal failure which has been called hepatorenal syndrome (HRS). Some reports have pointed out that serum creatinine levels frequently failed to rise above normal levels even when glomerular filtration rate (GFR) is very low in cirrhotic patients with hepatorenal syndrome. The aim of this study was to determine if estimation of serum cystatin C could replace creatinine clearance in routine GFR determinations for patients with cirrhosis.

METHODS

Serum cystatin C, creatinine clearance (Clcr), and 99mTc-DTPA clearance were determined in 26 patients with cirrhosis. According to Child-Pugh's classification, 21 patients were in group C and 5 were in Group B.

RESULTS

Pearson correlation analyses showed that correlation between serum cystatin C and 99mTc-DTPA clearance was r=-0.522, p=0.006, between serum creatinine and 99mTc-DTPA was r=-0.373, p=0.06. The results of our study demonstrated that neither serum creatinine nor creatinine clearance (Clcr) were good indicators of hepatorenal syndrome because the mean value for Clcr was found to be higher than Tc-DTPA clearance, and there was no correlation between these two parameters (r=0.059). Additionally, the mean value of serum creatinine was found to be within the normal range, whereas the mean DTPA clearance level was lower than normal range.

CONCLUSIONS

This finding could be explained by the fact that cirrhotic patients with poor nutrition may have decreased protein intake, low muscle mass and lack of converting capacity of creatine to creatinine. Thus, we suggest that serum cystatin C assay, which has good analytical performance, could replace or at least be added to creatinine measurement for GFR assessment in patients with cirrhosis.

Transjugular intrahepatic portosystemic shunt in hepatorenal syndrome: effects on renal function and vasoactive systems

Little information exists on the effects of transjugular intrahepatic portosystemic shunts (TIPS) in the management of cirrhotic patients with hepatorenal syndrome (HRS). The current study was aimed to prospectively evaluate the effects of TIPS on renal function and vasoactive systems in patients with type I HRS. Glomerular filtration rate (GFR) (inulin clearance), renal plasma flow (RPF) (para-aminohippurate clearance), plasma renin activity (PRA), aldosterone (ALDO), norepinephrine (NE), and endothelin (ET) were determined in baseline conditions and at different time intervals after TIPS in 7 patients with type I HRS. TIPS induced a marked reduction of portal pressure gradient (PPG) (20 +/- 1 to 10 +/- 1 mm Hg; P < .05). Renal function improved in 6 of the 7 patients. Serum creatinine and blood urea nitrogen (BUN) decreased from 5 +/- 0.8 and 109 +/- 7 to 1.8 +/- 0.4 mg/dL and 56 +/- 11 mg/dL, respectively (P < .05 for both), and GFR and RPF increased from 9 +/- 4 and 103 +/- 33 to 27 +/- 7 mL/min and 233 +/- 40 mL/min, respectively (P < .05 for both), 30 days after TIPS. These beneficial effects on renal function were associated with a significant (P < .05) reduction of PRA (18 +/- 5 to 3 +/- 1 ng/mL x h), ALDO (279 +/- 58 to 99 +/- 56 ng/dL), and NE (1,257 +/- 187 to 612 +/- 197 pg/mL). ET did not change significantly (28 +/- 8 to 27 +/- 11 pg/mL). Mean survival was 4.7 +/- 2 months (0.3-17 months). Three patients remained alive more than 3 months after TIPS insertion. In conclusion, TIPS improves renal function and reduces the activity of the renin-angiotensin and sympathetic nervous systems in cirrhotic patients with type I HRS. Nevertheless, the efficacy of TIPS in the management of these patients should be confirmed in controlled investigations.

The renal sympathetic and renin-angiotensin response to lower body negative pressure in well-compensated cirrhosis

BACKGROUND & AIMS

Certain antinatriuretic hormonal systems may be involved in the subclinical sodium handling abnormality in preascitic cirrhosis. The aims of this study were to determine the following in preascitic cirrhosis: (1) basal activity of the renal sympathetic and renin-angiotensin systems and (2) the relationship between the response of these systems to lower body negative pressure and sodium excretion.

METHODS

Seven preascitic cirrhotic patients and 9 age- and sex-matched controls were studied on a 150 mmol sodium per day diet. Systemic and renal hemodynamics, renal neurohormonal secretion rates, and sodium excretion were assessed before, during increasing levels of, and after lower body negative pressure, each for 30 minutes.

RESULTS

Both groups responded with a significant decrease in central venous pressure (P < 0.01) that remained higher in the cirrhotics than in the controls throughout the study. Cirrhotics showed significant increases compared with controls in renal renin and angiotensin II secretion rates at -20 mm Hg of lower body negative pressure, which was associated with significant renal sodium retention (96 +/- 17 micromol/min vs. 218 +/- 21 micromol/min at baseline, P < 0.05), but there was no change in renal sympathetic activity.

CONCLUSIONS

In preascitic cirrhosis, sodium retention occurs in response to lower body negative pressure, which was associated with increased renal renin-angiotensin activity. Stimulation of the intrarenal renin-angiotensin system may be the initial renal pathophysiological change causing sodium retention in cirrhosis.

Acute renal failure following bone marrow transplantation

Acute renal failure (ARF) is one of the most frequent and potentially life threatening complications following bone marrow transplantation (BMT). Several renal syndromes that occur are either unique or occur with a disproportionate frequency post-BMT. Clinically ARF can be classified according to the time of onset post-BMT. Immediate ARF syndromes include tumor lysis syndrome and marrow-infusion associated toxicity, which usually occur within 5 days post-BMT. Hepatorenal-like syndrome secondary to venoocclusive disease occur within one month and is the most common cause of early ARF syndrome. The late renal syndromes, more than 4 weeks post-BMT, include BMT-associated nephropathy, which may be acute or chronic, and cyclosporin nephrotoxicity. Other non-specific causes of ARF such as sepsis, hypotension, volume depletion, nephrotoxic agents and obstructive uropathy can also occur at any time period. Frequently ARF is multifactorial in these patients with complicated clinical course. Therapeutic approach depend on the underlying etiology. Supportive treatment such as optimization of volume status and dialysis when indicated are important steps as specific therapy is rarely available. Therefore, efforts should be targeted to the prevention of ARF. This includes prophylaxis for tumor lysis syndrome and marrow infusion toxicity by hydration and alkaline diuresis, avoiding nephrotoxic agents, early recognition and treatment of infection and correction of volume depletion.

Reversibility of hepatorenal syndrome by prolonged administration of ornipressin and plasma volume expansion

Hepatorenal syndrome is caused by a marked vasoconstriction of the renal circulation. It is suggested that the renal vasoconstriction is related to an overactivity of vasoconstrictor systems secondary to a vasodilation of the arterial circulation that causes a reduction in effective arterial blood volume. To test this hypothesis, 16 cirrhotic patients with hepatorenal syndrome were treated with a combination of ornipressin, a potent vasoconstrictor agent, and plasma volume expansion with albumin to improve effective arterial blood volume. The combined treatment was administered either for 3 or 15 days (8 patients each), and the effects on renal function, vasoactive systems, and systemic hemodynamics were assessed. The 3-day treatment with ornipressin and albumin was associated with a normalization of the overactivity of renin-angiotensin and sympathetic nervous systems, a marked increase in atrial-natriuretic peptide levels, and only a slight improvement in renal function. However, when ornipressin and albumin were administered for 15 days, a remarkable improvement in renal function was observed, with normalization of serum-creatinine concentration, a marked increase in renal plasma flow and glomerular filtration rate, and a persistent suppression in the activity of vasoconstrictor systems. However, 3 of 8 patients on 15-day therapy treatment had to be discontinued because of ischemic complications. In conclusion, the decrease in effective arterial blood volume and the activation of vasoconstrictor systems play a crucial role in the pathogenesis of hepatorenal syndrome. Although the prolonged administration of ornipressin combined with plasma volume expansion reverses hepatorenal syndrome, this treatment should be used with great caution in clinical practice because of the risk of ischemic complications.

Hepatorenal syndrome: combined liver kidney transplants versus isolated liver transplant

BACKGROUND

As many as 38% of combined liver-kidney transplant (LKTx) procedures performed nationally may be done for the renal diagnosis of hepatorenal syndrome (HRS). This study was designed to compare the national results with those at our medical center and to determine if combined LKTx provides any benefit over isolated liver transplant (LTx) to HRS patients.

METHODS

Data on 29 combined LKTx and 79 HRS patients at our center were collected and compared with the national data on 414 LKTx and 2442 patients with serum creatinine >2.0 mg/dl receiving isolated LTx from 1988 to 1995.

RESULTS

United Network of Organ Sharing data revealed 5-year patient survival of 62.2% for LKTx recipients and 50.4% for patients with serum creatinine >2.0 mg/dl receiving isolated LTx (P=0.0001). Our center results demonstrated 5-year patient survival of 48.1% for LKTx patients, 67.1% for HRS patients receiving isolated LTx, and 70.1% for patients with serum creatinine >2.0 mg/dl receiving isolated LTx (P not significant comparing all groups). Intensive care unit status and preoperative dialysis rates were similar in those HRS patients who did and those who did not need future KTx.

CONCLUSION

National data would suggest a survival benefit of combined LKTx over isolated LTx for those patients with poor renal function, specifically those with HRS, whereas our center's results suggest otherwise. Unfortunately, we could not identify any preoperative risk factors in the HRS patients, or in the broader group of patients with renal insufficiency at our center, that would indicate the need for future renal transplantation. We believe that HRS patients can be successfully managed with isolated LTx.

Review: the controversy over the pathophysiology of ascites formation in cirrhosis

The pathogenesis of renal sodium retention and ascites formation in cirrhosis is a subject of much controversy. The generally accepted 'peripheral arterial vasodilatation hypothesis' seems to best explain the mechanism of sodium retention and other clinical findings, such as the hyperdynamic circulation of cirrhosis. However, recent data in pre-ascites and in early ascites do not seem to conform to the peripheral arterial vasodilatation hypothesis. Sodium handling abnormalities can be demonstrated in pre-ascitic cirrhosis when patients are challenged with a sodium load, in the absence of systemic vasodilatation or arterial underfilling. Therefore, an alternative hypothesis with a direct hepatorenal interaction, acting via sinusoidal portal hypertension and/or hepatic dysfunction as the affector mechanism, is proposed to be the initiating event in renal sodium retention in cirrhosis. The second and later process is the development of systemic arterial vasodilatation, possibly due to the presence of excess systemic vasodilators and/or decreased responsiveness of the vasculature to endogenous vasoconstrictors. This, in turn, will lead to a relatively underfilled circulation with consequent activation of neurohumoral systems, promoting further renal sodium retention as described by the peripheral arterial vasodilatation hypothesis and ultimately leading to ascites. When compensatory natriuretic mechanisms fail, refractory ascites develops and hepatorenal syndrome sets in. Thus, renal sodium retention in cirrhosis is the result of interplay of many factors, with direct hepatorenal interaction predominating in earlier stages of the cirrhotic process, while systemic vasodilatation becomes a more important pathogenetic factor as the disease progresses.

Risk factors and outcome of 107 patients with decompensated liver disease and acute renal failure (including 26 patients with hepatorenal syndrome): the role of hemodialysis

The prognosis of acute renal failure in patients with preexisting liver decompensation is poor, and hemodialysis is considered futile, especially for hepatorenal syndrome (HRS). Since we observed a more favorable outcome in some patients, we retrospectively evaluated 107 patients with decompensated liver disease and acute renal failure (serum creatinine > 200 mumol/L) treated at the medical department of a university hospital in a 10-year period (1980-1990). HRS in the strict sense (urine-Na < 20 mmol/L while on furosemide) was diagnosed in 26 of 107 patients (24%). Renal function remained compensated in 25 patients, while 82 patients fulfilled the criteria for dialysis treatment (creatinine > 500 mumol/L and/or diuresis < 500 mL/day). In contrast to the current doctrine, 38 of the 82 patients were given hemodialysis (46%). Using the Cox proportional hazard model, the relative risk (presence vs. absence of a risk factor) of dying was increased 8.2-fold (3.9-17.2) in patients with thrombocytopenia < 100/nL, 3.9-fold (1.4-11.3) in those with hepatic encephalopathy and prothrombin time < 30%, 2.8-fold (1.6-4.8) in patients with malignoma, and 2.7-fold (1.5-4.8) in patients not submitted to dialysis despite its indication. In the CART statistics (classification and regression trees), the 33 patients with the poorest outcome were characterized exclusively by thrombocytopenia < 100/nL. HRS in the strict sense was not an independent risk factor. The CART group of 43 patients with favorable prognosis (compensated renal failure or treatment by hemodialysis, absent malignancy) had a 1-year survival rate of 38%. We conclude that thrombocytopenia, encephalopathy, and malignoma, but not HRS per se, are fatal signs that make hemodialysis futile in patients with acute renal failure and decompensated liver disease.

Renal handling of drugs and amino acids after impairment of kidney or liver function--influences of maturity and protective treatment

Renal tubular cells are involved both in secretion and in reabsorption processes within the kidney. Normally, most xenobiotics are secreted into the urine at the basolateral membrane of the tubular cell, whereas amino acids are reabsorbed quantitatively at the luminal side. Under different pathological or experimental circumstances, these transport steps may be changed, e.g., they may be reduced by renal impairment (reduction of kidney mass, renal ischemia, administration of nephrotoxins) or they may be enhanced after stimulation of transport carriers. Furthermore, a distinct interrelationship exists between excretory functions of the kidney and the liver. That means liver injury can influence renal transport systems also (hepato-renal syndrome). In this review, the following aspects were included: based upon general information concerning different transport pathways for xenobiotics and amino acids within kidney cells and upon a brief characterization of methods for testing impairment of kidney function, the maturation of renal transport and its stimulation are described. Similarities and differences between the postnatal development of kidney function and the increase of renal transport capacity after suitable stimulatory treatment by, for example, various hormones or xenobiotics are reviewed. Especially, renal transport in acute renal failure is described for individuals of different ages. Depending upon the maturity of kidney function, age differences in susceptibility to kidney injury occur: if energy-requiring processes are involved in the transport of the respective substance, then adults, in general, are more susceptible to renal failure than young individuals, because in immature organisms, anaerobic energy production predominates within the kidney. On the other hand, adult animals can better compensate for the loss of renal tissue (partial nephrectomy). With respect to stimulation of renal transport capacity after repeated pretreatment with suitable substances, age differences also exist: most stimulatory schedules are more effective in young, developing individuals than in mature animals. Therefore, the consequences of the stimulation of renal transport can be different in animals of different ages and are discussed in detail. Furthermore, the extent of stimulation is different for the transporters located at the basolateral and at the luminal membranes: obviously the tubular secretion at the contraluminal membrane can be stimulated more effectively than reabsorption processes at the luminal side.