Hepatorenal syndrome

Renin angiotensin system in liver diseases: Friend or foe?

In the last three decades, the understanding of the renin angiotensin system (RAS) has been changed by the discoveries of functional local systems, novel biologically active peptides, additional specific receptors, alternative pathways of angiotensin (Ang) II generation, and new roles for enzymes and precursor components other than those in Ang II synthesis. In this regard, the discovery that Ang-(1-7) opposes the pressor, proliferative, pro-fibrotic, and pro-inflammatory effects mediated by Ang II has contributed to the realization that the RAS is composed of two axes. The first axis consists of the angiotensin-converting enzyme (ACE), with Ang II as the end product, and the angiotensin type 1 (AT1) receptor as the main effector mediating the biological actions of Ang II. The second axis results from ACE2-mediated hydrolysis of Ang II, leading to the production of Ang-(1-7), with the Mas receptor as the main effector conveying the vasodilatory, anti-proliferative, anti-fibrotic, and anti-inflammatory effects of Ang-(1-7). Experimental and clinical studies have shown that both axes of the RAS may take part in the pathogenesis of liver diseases. In this manuscript, we summarize the current evidence regarding the role of RAS in hepatic cirrhosis and its complications, including hemodynamic changes and hepatorenal syndrome. The therapeutic potential of the modulation of RAS molecules in liver diseases is also discussed.

Hepatorenal Syndrome: Diagnosis and Treatment - newsreel

Hepatorenal syndrome (HRS) is defined as renal failure that occurs in the presence of severe acute or chronic liver disease in the absence of underlying renal pathology. Due to the functional nature of the disease and the absence of specific diagnostic markers, HRS diagnosis is determined based on positive criteria associated with excluding other causes of renal failure in patients with liver cirrhosis and ascites. Differentiation from other types of acute or chronic renal disease is extremely difficult and therapeutic options are limited, prophylactic behavior is most appropriate in patients with severe hepatic disease and risk factors for the installation of hepatorenal syndrome. Highlighting all precipitating factors of acute renal insufficiency and therapeutic modalities in order to minimize adverse events is an important step in improving the follow-up of the patients with liver cirrhosis. The prognosis is reserved especially for type 1 HRS. Liver transplantation is the best option for patients without contraindications. The therapies introduced in recent years, such as vasoconstrictor drugs or transjugular intrahepatic portosystemic shunt are effective methods in the renal function improvement.

Relationship between serum levels of endotoxin and PGI2/TXA2 and hepatorenal syndrome

AIM: To explore the relationship between serum levels of endotoxin and prostaglandin I₂ (PGI₂)/ thromboxane A₂ (TXA₂) and development of hepatorenal syndrome (HRS) by analyzing clinical data, routine laboratory parameters, rate of infection, serum levels of procalcitonin (PCT), PGI2 and TXA₂ in cirrhotic patients with ascites and type 1 HRS.

METHODS: Thirty-eight cirrhotic inpatients with ascites and type 1 HRS and 41 cirrhotic inpatients with ascites but normal renal function, who were treated at our hospital between January 2009 and December 2011, were enrolled and divided into a HRS group and a non-HRS group, respectively. Clinical data, cirrhosis etiology, rate and type of infections, Child-Pugh classification, model for end-stage liver disease (MELD) score, systemic inflammatory response (SIRS) score and mean arterial pressure (MAP) were recorded. Blood samples were obtained for laboratory analysis of liver function, renal function, electrolytes, PCT, PGI₂ and TXA₂. All the data were compared between the two groups, and correlation between PCT and PGI₂/TXA₂ was analyzed in the HRS group.

RESULTS: Rate of infection, SIRS score, serum levels of PCT and TXA₂ were significantly higher in the HRS group than in the non-HRS group [73.6% vs 29.2%, 2.1 ± 1.1 vs 0.6 ± 0.6, 8.72 (3.14, 31.68) ng/mL vs 0.11 (0.04, 0.45) ng/mL, 7432 pg/mL ± 2186 pg/mL vs 5064 pg/mL ± 2007 pg/mL; all P < 0.05], while serum levels of PGI₂/TXA₂ were significantly lower in the HRS group (4.79 ± 1.58 vs 7.47 ± 2.36, t = 2.26, P < 0.05). Age, gender, cause of the disease, Child-Pugh classification, and PGI₂ levels did not differ significantly between the two groups (all P > 0.05). In the HRS group, serum levels of PCT and PGI₂/TXA₂ showed a significant negative correlation (r = -0. 64, P < 0.05).

CONCLUSION: Cirrhotic patients are prone to develop endotoxemia and PGI₂/TXA₂ imbalance. Elevated endotoxin and decreased PGI₂/TXA₂ are closely associated with the development of HRS.

Effect of heme oxygenase-1 on renal function in rats with liver cirrhosis

AIM: To investigate the role of heme oxygenase-1 (HO-1) in pathogenesis of experimental hepatorenal syndrome (HRS).

METHODS: Rats were divided into liver cirrhotic group, zinc protoporphyrin IX (ZnPP) treatment group, cobalt protoporphyrin (CoPP) treatment group and sham group. Biliary cirrhosis was established by bile duct ligation in the first three groups. Rats in the ZnPP and CoPP treatment groups received intraperitoneal injection of ZnPP and CoPP, respectively, 24 h before sample collection. Expression of HO-1 mRNA in kidney was detected by reverse-transcription polymerase chain reaction, while protein expression was determined by immunohistochemical analysis. Hematoxylin and eosin staining was performed to observe liver cirrhosis and renal structure. Renal artery blood flow, mean arterial pressure and portal vein pressure, 24 h total urinary volume, serum and urine sodium concentrations, and creatinine clearance rate (Ccr) were also measured.

RESULTS: The HO-1 mRNA and protein expression levels in kidney, 24 h total urinary volume, renal artery blood flow, serum and urine sodium concentration and Ccr were lower in cirrhotic group than in sham group (P < 0.05). However, they were significantly lower in ZnPP treatment group than in cirrhotic group and significantly higher in CoPP treatment group than in cirrhotic group (P < 0.05).

CONCLUSION: Low HO-1 expression level in kidney is an important factor for experimental HRS.

Hemodynamic studies in acute-on-chronic liver failure

BACKGROUND

Patients with decompensated cirrhosis and acute liver failure have circulatory dysfunctions leading to high portal pressure and cardiac output (CO) and low systemic vascular resistance (SVR). Circulatory changes in acute-on-chronic liver failure (ACLF) patients have not been studied. We studied the portal, systemic, and pulmonary hemodynamics in patients with ACLF and compared them with compensated and decompensated cirrhotics.

PATIENTS AND METHODS

Clinical features and hemodynamic profile were studied in patients with ACLF and compared with age- and sex-matched compensated and decompensated cirrhotics with portal hypertension.

RESULTS

The study cohort comprised 144 patients categorized into one of three groups (ACLF, compensated cirrhosis, and decompensated cirrhosis), with 48 (33%) patients in each group. All values are given as the mean +/- standard deviation, except for frequencies (%). The mean arterial pressure (MAP) and SVR were lower in the ACLF than the compensated group and were similar to those of the decompensated group (MAP 90 +/- 16 vs. 99 +/- 15 vs. 96 +/- 16 mmHg; SVR 912 +/- 435 vs. 1350 +/- 449 vs. 891 +/- 333 dyn s/cm(5)). The mean CO of the ACLF patients was higher than that of the compensated group and similar to that of the decompensated group (CO 8.9 +/- 3.5 vs. 6.1 +/- 1.7 vs. 9.0 +/- 3.0 l/min). The pulmonary vascular resistance (PVR) and pulmonary capillary wedge pressures (PCWP) were similar in all the three groups (PVR 78 +/- 48 vs. 109 +/- 70 vs. 61 +/- 47 dyn s/cm(5); PCWP 8 +/- 4 vs. 8 +/- 4 vs. 10 +/- 5 mmHg). The mean hepatic venous pressure gradient (HVPG) in the ACLF group was 15.1 +/- 6.3 mmHg, which was significantly higher than that of the compensated group (11.7 +/- 6.3 mmHg), but lower than that of the decompensated cirrhosis group (20.2 +/- 6.0 mmHg). When patients of ACLF were categorized on the basis of their variceal size, the mean HVPG in ACLF patients with small varices was similar to that of compensated cirrhotics (13.7 +/- 5.7 vs. 11.7 +/- 6.3 mmHg; P = 0.146), while in the ACLF patients with large varices, the HVPG was comparable to that of the decompensated cirrhotics (18.7 +/- 6.6 vs. 20.2 +/- 6.0 mmHg; P = 0.442).

CONCLUSIONS

The systemic hemodynamics in patients with ACLF is similar to that in decompensated cirrhotics. The portal pressure in these patients is higher than that in the compensated cirrhotics, and in the subgroup with large varices, it becomes similar to that of decompensated cirrhotics.

Midodrine and Octreotide in Treatment of Cirrhosis-Related Hemodynamic Complications

Objective:

To review studies evaluating the use of midodrine and octreotide in hemodynamic complications of cirrhosis, including ascites and hepatorenal syndrome.

Data Sources:

Searches of MEDLINE (1966–September 2008) and EMBASE (1974–September 2008) were conducted using the terms midodrine, octreotide, hepatorenal syndrome, ascites, cirrhosis, and paracentesis-induced circulatory dysfunction. Literature review was limited to English-language, human studies.

Study Selection and Data Extraction:

Studies identified from data sources were considered for review. Studies were excluded if primary therapy involved any of the following: transjugular intrahepatic portosystemic shunt procedure, medications other than midodrine or octreotide, or patients included for treatment or prevention of portal hypertension and/or variceal bleeding. Pharmacokinetic/pharmacodynamic studies and studies using retrospective data collection were excluded. Seven studies were included in this review.

Data Synthesis:

Midodrine and octreotide in combination or alone have shown conflicting results for systemic and renal hemodynamics and renal function in patients with cirrhosis-related complications. Patients with ascites being treated with midodrine, alone or in combination with octreotide, showed significant changes in systemic hemodynamics, without a correlating change in renal perfusion. Studies comparing the use of midodrine with use of albumin for the prevention of paracentesis-induced circulatory dysfunction (PICD) showed no incidence of PICD in either treatment group. In hepatorenal syndrome, patients using midodrine with octreotide showed significant changes in systemic hemodynamics and improvements in renal perfusion. This regimen's effect on survival is yet to be determined,

Conclusions:

Available evidence shows inconsistent results for the effectiveness and safety of midodrine and octreotide use in cirrhotic patients. Because of the contradictory results, longer treatment duration and increased number of study participants are necessary to determine the proper use of midodrine and octreotide in these patients.

Development of hepatorenal syndrome in bile duct ligated rats

AIM

To evaluate in bile duct ligated rats whether there were progressive alterations of renal function without changes in histopathology.

METHODS

Male Wistar rats were submitted to sham-surgery or bile duct ligation (BDL) and divided according to the post-procedure time (2, 4 and 6-wk). To determine renal function parameters, rats were placed in metabolic cages and, at the end of the experiment, blood and urine samples were obtained. Histology and hydroxyproline content were analyzed in liver and renal tissue.

RESULTS

Rats with 2 wk of BDL increased free water clearance (P = 0.02), reduced urinary osmolality (P = 0.03) and serum creatinine (P = 0.01) in comparison to the sham group. In contrast, rats at 6 wk of BDL showed features of HRS, including significant increase in serum creatinine and reductions in creatinine clearance, water excretion and urinary sodium concentration. Rats with 4 wk of BDL exhibited an intermediate stage of renal dysfunction. Progressive hepatic fibrosis according to post-procedure time was confirmed by histology. The increased levels of liver hydroxyproline contrasted with the absence of structural changes in the kidney, as assessed by histology and unchanged hydroxyproline content in renal tissue.

CONCLUSION

Our data show that BDL produced progressive renal dysfunction without structural changes in the kidney, characterizing HRS. The present model will be useful to understand the pathophysiology of HRS.

Lack of renal improvement with nonselective endothelin antagonism with tezosentan in type 2 hepatorenal syndrome

Renal vasoconstriction is a key factor in the development of hepatorenal syndrome (HRS) and may be secondary to increased activities of endothelin-1, a potent renal vasoconstrictor. To assess the effects of tezosentan, a nonselective endothelin receptor antagonist, on renal function in patients with type 2 HRS, six male patients, 56.3 +/- 2.5 years old, with cirrhosis and type 2 HRS were treated with tezosentan; ascending doses of 0.3, 1.0, and 3.0 mg/hour, each for 24 hours, were used for the initial 2 patients, but a constant dose of 0.3 mg/hour for up to 7 days was used for the remaining 4 patients. The glomerular filtration rate, renal plasma flow, 24-hour urinary volume, mean arterial pressure (MAP), heart rate, tezosentan levels, and vasoactive hormones were measured daily. Albumin was given as required. The study was stopped early because of concerns about the safety of tezosentan in type 2 HRS. Five patients discontinued the study early; one stopped within 4 hours because of systemic hypotension (MAP < 70 mm Hg), and 4 patients stopped at approximately 4 days because of concerns about worsening renal function (serum creatinine increased from 180 +/- 21 to 222 +/- 58 micromol/L, P > 0.05) and decreasing urine volume (P = 0.03) but without a significant change in MAP. The plasma tezosentan concentrations were 79 +/- 34 ng/mL at a steady state during infusion at 0.3 mg/hour. The plasma endothelin-1 concentrations increased from 2.7 +/- 0.3 pg/mL at the baseline to 19.1 +/- 7.3 pg/mL (P < 0.05).

CONCLUSION

An endothelin receptor blockade potentially can cause a deterioration in renal function in patients with cirrhosis and type 2 HRS. Caution should be taken in future studies using endothelin receptor antagonists in these patients.

Relationship between laboratory parameters and intensive care unit stay post-liver transplantation: proposal of a model

The aim of this study was to create a model that forecasted the stay in the intensive care unit in post-liver transplantation.

METHODS

Twenty-three consecutive patients who underwent liver transplantation provided samples for serum sodium, serum creatinine, total bilirubin, cholesterol, aspartate and alanine aminotransferase, alkaline phosphatase (ALP), albumin, and platelet count for correlation together with age at transplantation in a Pearson correlation model with intensive care unit stay. Multivariate analysis used a regression model to evaluate the relationship between the dependent variable "intensive care unit stay" and the predictor variables that were correlated by a Pearson correlation test. To test the acceptability and strength of the model, analyses of variance was performed and a multiple correlation coefficient R was calculated for the model.

RESULTS

Pearson correlation test showed a strong correlation between intensive care unit stay and creatinine (correlation coefficient = 0.34, P = .03), serum sodium (correlation coefficient = -0.42, P < .01), and total bilirubin (correlation coefficient = -0.29, P = .06). Other variables showed no significant correlation, namely correlation coefficients < 0.24 (P > .1). The final model to evaluate the relationship between the dependent variable "intensive care unit stay" and laboratory parameters included ALP, serum creatinine, serum sodium, and total bilirubin as well as a correction for age.

CONCLUSIONS

The most significant parameters were total bilirubin, serum creatinine, and serum sodium. The proposal model significantly correlated with the variable "intensive care unit stay." Such data are particularly important since increased intensive care unit stay correlates with a significant reduction in 1-year survival rate.

Budd-Chiari syndrome from an advanced practice nurse perspective

PURPOSE

To provide nurse practitioners (NPs) with a case study and literature review of Budd-Chiari syndrome (BCS). This rare liver disease has a multitude of clinical presentations that NPs may encounter in the primary care setting.

DATA SOURCE

A literature search was conducted in Pub-Med and CINAHL using key search words. Information for the case study was obtained from a patient and his gastroenterology specialist, who is a foremost expert in this field.

CONCLUSION

BCS is complex and may be difficult to diagnose because of its atypical clinical presentation. Delayed diagnosis can affect the quality and quantity of a patient's life. Increasing NPs' awareness about this rare condition through a case presentation and review of the literature emphasizes the major factors for accurate diagnosis.

IMPLICATIONS FOR PRACTICE

Knowledge of BCS can assist the NP in identifying this syndrome and making prompt, appropriate referrals.