Review article: pathogenesis and pathophysiology of hepatorenal syndrome--is there scope for prevention?

Pathophysiology of Hepatorenal Syndrome

Hepatorenal syndrome type 1 (HRS-1) is a unique form of acute kidney injury that affects individuals with decompensated cirrhosis with ascites. The primary mechanism leading to reduction of kidney function in HRS-1 is hemodynamic in nature. Cumulative evidence points to a cascade of events that led to a profound reduction in kidney perfusion. A state of increased intrahepatic vascular resistance characteristic of advanced cirrhosis and portal hypertension is accompanied by maladaptive peripheral arterial vasodilation and reduction in systemic vascular resistance and mean arterial pressure. As a result of a fall in effective arterial blood volume, there is a compensatory activation of the sympathetic nervous system and the renin-angiotensin system, local renal vasoconstriction, loss of renal autoregulation, decrease in renal blood flow, and ultimately a fall in glomerular filtration rate. Systemic release of nitric oxide stimulated by the fibrotic liver, bacterial translocation, and inflammation constitute key components of the pathogenesis. While angiotensin II and noradrenaline remain the critical mediators of renal arterial and arteriolar vasoconstriction, other novel molecules have been recently implicated. Although the above-described mechanistic pathway remains the backbone of the pathogenesis of HRS-1, other noxious elements may be present in advanced cirrhosis and likely contribute to the renal impairment. Direct liver-kidney crosstalk via the hepatorenal sympathetic reflex can further reduce renal blood flow independently of the systemic derangements. Tense ascites may lead to intraabdominal hypertension and abdominal compartment syndrome. Cardio-hemodynamic processes have also been increasingly recognized. Porto-pulmonary hypertension, cirrhotic cardiomyopathy, and abdominal compartment syndrome may lead to renal congestion and complicate the course of HRS-1. In addition, a degree of ischemic or toxic (cholemic) tubular injury may overlap with the underlying circulatory dysfunction and further exacerbate the course of acute kidney injury. Improving our understanding of the pathogenesis of HRS-1 may lead to improvements in therapeutic options for this seriously ill population.

Renoprotective effects of zinc sulfate against transient liver ischemia/reperfusion injury in rats

Objectives

Liver ischemia/reperfusion damage frequently occurs in setting of hepatic resection and liver transplantation. It leads to disturbance in remote organs such as heart, lung and kidneys. This study explored the consequences of hepatic ischemia/reperfusion on the oxidative stress parameters, biochemical factors, and histopathological alterations in the kidney's rats, as well as evaluated the role of zinc sulfate on above-mentioned parameters.

Materials and methods

Twenty-eight male Wistar rats were accidently assigned into four groups (n = 7). They were Sham, ischemia/reperfusion, zinc sulfate pretreatment, and zinc sulfate pretreatment + ischemia/reperfusion groups. Sham group: obtained normal saline (2 ml/day, seven consecutive days), intraperitoneally, zinc sulfate pretreatment group: obtained zinc sulfate (5 mg/kg, seven consecutive days, intraperitoneally). Ischemia/reperfusion group: obtained normal saline as mentioned previous, then rats experienced the partial ischemia (%70) for 45 min followed by 60 min reperfusion. Zinc sulfate pretreatment group: obtained zinc sulfate as mentioned previous, then rats experience the partial ischemia/reperfusion as presented earlier. At the end of investigation, blood was withdrawn, liver and renal tissues were removed. Then, biochemical and oxidative stress parameters, and histological changes were evaluated in the mentioned tissues.

Results

The findings of this experiment indicated that zinc sulfate markedly reduced the serum levels of liver and kidney function tests in relative to ischemia/reperfusion group. Also, antioxidant enzymes activity, ferric reducing antioxidant power, and nitric oxide significantly increased, while malondialdehyde level declined in the renal tissue of zinc sulfate + ischemia/reperfusion group compared to ischemia/reperfusion rats. Furthermore, zinc sulfate alleviated the liver and kidneys histopathological alterations following ischemia/reperfusion.

Conclusion

Zinc sulfate ameliorated liver and kidney function, and improved oxidant-antioxidant balance in favor of antioxidants. It is suggested that zinc sulfate may be beneficial effects on hepato-renal injury after ischemia/reperfusion.

COVID-19 and hepatorenal syndrome

Coronavirus disease 2019 (COVID-19) is a highly infectious disease which emerged into a global pandemic. Although it primarily causes respiratory symptoms for affected patients, COVID-19 was shown to have multi-organ manifestations. Elevated liver enzymes appear to be commonly observed during the course of COVID-19, and there have been numerous reports of liver injury secondary to COVID-19 infection. It has been established that patients with pre-existing chronic liver disease (CLD) are more likely to have poorer outcomes following COVID-19 infection compared to those without CLD. Co-morbidities such as diabetes, hypertension, obesity, cardiovascular and chronic kidney disease frequently co-exist in individuals living with CLD, and a substantial population may also live with some degree of frailty. The mechanisms of how COVID-19 induces liver injury have been postulated. Hepatorenal syndrome (HRS) is the occurrence of kidney dysfunction in patients with severe CLD/fulminant liver failure in the absence of another identifiable cause, and is usually a marker of severe decompensated liver disease. Select reports of HRS following acute COVID-19 infection have been presented, although the risk factors and pathophysiological mechanisms leading to HRS in COVID-19 infection or following COVID-19 treatment remain largely unestablished due to the relative lack and novelty of published data. Evidence discussing the management of HRS in high-dependency care and intensive care contexts is only emerging. In this article, we provide an overview on the speculative pathophysiological mechanisms of COVID-19 induced HRS and propose strategies for clinical diagnosis and management to optimize outcomes in this scenario.

Interplay of cardiovascular mediators, oxidative stress and inflammation in liver disease and its complications

The liver is a crucial metabolic organ that has a key role in maintaining immune and endocrine homeostasis. Accumulating evidence suggests that chronic liver disease might promote the development of various cardiac disorders (such as arrhythmias and cardiomyopathy) and circulatory complications (including systemic, splanchnic and pulmonary complications), which can eventually culminate in clinical conditions ranging from portal and pulmonary hypertension to pulmonary, cardiac and renal failure, ascites and encephalopathy. Liver diseases can affect cardiovascular function during the early stages of disease progression. The development of cardiovascular diseases in patients with chronic liver failure is associated with increased morbidity and mortality, and cardiovascular complications can in turn affect liver function and liver disease progression. Furthermore, numerous infectious, inflammatory, metabolic and genetic diseases, as well as alcohol abuse can also influence both hepatic and cardiovascular outcomes. In this Review, we highlight how chronic liver diseases and associated cardiovascular effects can influence different organ pathologies. Furthermore, we explore the potential roles of inflammation, oxidative stress, vasoactive mediator imbalance, dysregulated endocannabinoid and autonomic nervous systems and endothelial dysfunction in mediating the complex interplay between the liver and the systemic vasculature that results in the development of the extrahepatic complications of chronic liver disease. The roles of ageing, sex, the gut microbiome and organ transplantation in this complex interplay are also discussed.

Reappraising the spectrum of AKI and hepatorenal syndrome in patients with cirrhosis

The occurrence of acute kidney injury (AKI) in patients with end-stage liver disease constitutes one of the most challenging clinical scenarios in in-hospital and critical care medicine. Hepatorenal syndrome type 1 (HRS-1), which is a specific type of AKI that occurs in the context of advanced cirrhosis and portal hypertension, is associated with particularly high mortality. The pathogenesis of HRS-1 is largely viewed as a functional derangement that ultimately affects renal vasculature tone. However, new insights suggest that non-haemodynamic tubulo-toxic factors, such as endotoxins and bile acids, might mediate parenchymal renal injury in patients with cirrhosis, suggesting that concurrent mechanisms, including those traditionally associated with HRS-1 and non-traditional factors, might contribute to the development of AKI in patients with cirrhosis. Moreover, histological evidence of morphological abnormalities in the kidneys of patients with cirrhosis and renal dysfunction has prompted the functional nature of HRS-1 to be re-examined. From a clinical perspective, a diagnosis of HRS-1 guides utilization of vasoconstrictive therapy and decisions regarding renal replacement therapy. Patients with cirrhosis are at risk of AKI owing to a wide range of factors. However, the tools currently available to ascertain the diagnosis of HRS-1 and guide therapy are suboptimal. Short of liver transplantation, goal-directed haemodynamically targeted pharmacotherapy remains the cornerstone of treatment for this condition; improved understanding of the underlying pathogenic mechanisms might lead to better clinical outcomes. Here, we examine our current understanding of the pathophysiology of HRS-1 and existing challenges in its diagnosis and treatment.

Terlipressin versus other vasoactive drugs for hepatorenal syndrome

BACKGROUND

Hepatorenal syndrome is defined as severe renal failure occurring in people with cirrhosis and ascites. Systematic reviews of randomised clinical trials found that, compared with placebo, terlipressin may reduce mortality and improve renal function in people with hepatorenal syndrome, but we need current evidence from systematic reviews on the benefits and harms of terlipressin versus other vasoactive drugs.

OBJECTIVES

To evaluate the beneficial and harmful effects of terlipressin versus other vasoactive drugs for people with hepatorenal syndrome.

SEARCH METHODS

We searched The Cochrane Hepato-Biliary Group Controlled Trials Register, CENTRAL, MEDLINE, Embase, and Science Citation Index Expanded; conducted manual searches of references in relevant literature; and wrote to experts and pharmaceutical companies (date of last search November 2016).

SELECTION CRITERIA

Randomised clinical trials comparing terlipressin versus any other type of vasoactive drugs for hepatorenal syndrome. We allowed albumin and other cointerventions if provided equally in the comparison groups.

DATA COLLECTION AND ANALYSIS

Three authors independently extracted data. The primary outcomes were mortality, hepatorenal syndrome (persistent hepatorenal syndrome despite treatment), and serious adverse events. We conducted meta-analyses and present the results as risk ratios (RR) with 95% confidence intervals (CI). We performed sensitivity, subgroup, and Trial Sequential Analyses and evaluated bias control based on the Cochrane Hepato-Biliary Group domains.

MAIN RESULTS

We included 10 randomised clinical trials with 474 participants. The trials compared terlipressin versus noradrenaline (seven trials), octreotide (one trial), midodrine and octreotide (one trial), or dopamine (one trial). All participants in both groups received albumin as cointervention. We classified two trials at low risk of bias and eight trials at high risk of bias in the assessment of mortality and all trials at high risk of bias for remaining outcomes. In five trials, investigators specifically stated that they did not receive funding from for-profit organisations. We had no information about the funding source from the remaining five trials.Terlipressin was not superior or inferior compared with other vasoactive drugs in regard to mortality when including the two trials with a low risk of bias (RR 0.92, 95% CI 0.63 to 1.36; 94 participants, very low quality evidence) or when including all 10 trials (RR 0.96, 95% CI 0.88 to 1.06; 474 participants; I² = 0%; very low quality evidence). One meta-analysis including nine trials suggested a beneficial effect of terlipressin on hepatorenal syndrome (RR 0.79, 95% CI 0.63 to 0.99; 394 participants; I² = 26%; very low quality evidence). Due to the high mortality of hepatorenal syndrome, the registration of other serious adverse events is uncertain, but comparing terlipressin and other vasoactive drugs we found no significant difference (RR 0.96, 95% CI 0.88 to 1.06; 474 participants; I² = 0%; very low quality evidence). Several trials did not report systematically of adverse events, but terlipressin seemed to increase the risks of diarrhoea or abdominal pain, or both (RR 3.50, 95% CI 1.19 to 10.27; 221 participants; 5 trials, I² = 0%). However, Trial Sequential Analyses found insufficient evidence to support or refute any differences between interventions for all outcomes. Considering reversal of hepatorenal syndrome, subgroup analyses on the type of other vasoactive drugs found that terlipressin was superior compared with midodrine and octreotide (RR 0.47, 95% CI 0.30 to 0.72) or octreotide alone (RR 0.56, 95% CI 0.33 to 0.96), but each subgroup only included one small trial. None of the remaining subgroup or sensitivity analyses found differences between terlipressin and other vasoactive drugs. We downgraded the evidence to very low quality because of the high risk of bias, imprecision, and the results of the Trial Sequential Analyses.

AUTHORS' CONCLUSIONS

This review found insufficient evidence to support or refute beneficial or harmful effects of terlipressin and albumin versus other vasoactive drugs and albumin. Additional research is needed to evaluate if clinically meaningful differences exist between interventions.

Dual Organ Duel: The Hepatorenal Axis

Recent developments in our understanding of the pathogenesis of kidney disease in the setting of liver failure have highlighted that kidney injury, rather than occurring in isolation, is a marker of systemic disease and poor prognosis. The differential diagnosis of kidney disease associated with liver failure is broader than formerly described and new biopsy data, along with better acute kidney injury classification tools, have increased appreciation for distinct pathophysiological mechanisms. Evidence suggests that acute kidney injury contributes to worsening hepatic failure by directly injuring hepatic cells and by imposing restrictions on therapeutic strategies for portal hypertension. Furthermore, kidney injury limits the use of various therapeutic agents and increases their toxicity due to altered pharmacodynamics. A greater appreciation of CKD in this population is also overdue because management decisions are affected and increased vigilance may avoid further kidney injury. A multidisciplinary approach to kidney injury in the setting of liver failure will enable targeted therapeutic strategies that are safe and effective and serve to guide further research, while limiting clinical potential for harm. Finally, new hepatitis C antiviral therapies promise to change the landscape of liver failure, and a discussion of kidney risk factors and antiviral therapy of patients with kidney disease and hepatitis C is worthwhile.

Terlipressin versus placebo or no intervention for people with cirrhosis and hepatorenal syndrome

BACKGROUND

Hepatorenal syndrome is a potentially reversible renal failure associated with severe liver disease. The disease is relatively common among people with decompensated cirrhosis. Terlipressin is a drug that increases the blood flow to the kidneys by constricting blood vessels. The previous version of this systematic review found a potential beneficial effect of terlipressin on mortality and renal function in people with cirrhosis and hepatorenal syndrome.

OBJECTIVES

To assess the beneficial and harmful effects of terlipressin versus placebo/no intervention for people with cirrhosis and hepatorenal syndrome.

SEARCH METHODS

We identified eligible trials through searches of the Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) in the Cochrane Library, MEDLINE, Embase, and Science Citation Index Expanded, and manual searches until 21 November 2016.

SELECTION CRITERIA

Randomised clinical trials (RCTs) involving participants with cirrhosis and type 1 or type 2 hepatorenal syndrome allocated to terlipressin versus placebo or no intervention. We allowed co-administration with albumin administered to both comparison groups.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data from trial reports and undertook correspondence with the authors. Primary outcomes were mortality, hepatorenal syndrome, and serious adverse events. We conducted sensitivity analyses of RCTs in which participants received albumin, subgroup analyses of participants with type 1 or type 2 hepatorenal syndrome, and Trial Sequential Analyses to control random errors. We reported random-effects meta-analyses with risk ratios (RR) and 95% confidence intervals (CI). We assessed the risk of bias based on the Cochrane Hepato-Biliary Group domains. We graded the quality of the evidence using GRADE.

MAIN RESULTS

We included nine RCTs with a total of 534 participants with cirrhosis and ascites. One RCT had a low risk of bias for mortality and a high risk of bias for the remaining outcomes. All included trials had a high risk of bias for non-mortality outcomes. In total, 473 participants had type 1 hepatorenal syndrome. Seven RCTs specifically evaluated terlipressin and albumin. Terlipressin was associated with a beneficial effect on mortality when including all RCTs (RR 0.85, 95% CI 0.73 to 0.98; 534 participants; number needed to treat for an additional beneficial outcome (NNTB) 10.3 people; low-quality evidence). Trial Sequential Analysis including all RCTs also found a beneficial effect of terlipressin. Additional analyses showed a beneficial effect of terlipressin and albumin on reversal of hepatorenal syndrome (RR 0.63, 95% CI 0.48 to 0.82; 510 participants; 8 RCTs; NNTB 4 people; low-quality evidence). Terlipressin increased the risk of serious cardiovascular adverse events (RR 7.26, 95% CI 1.70 to 31.05; 234 participants; 4 RCTs), but it had no effect on the risk of serious adverse events when analysed as a composite outcome (RR 0.91, 95% CI 0.68 to 1.21; 534 participants; 9 RCTs; number needed to treat for an additional harmful outcome 24.5 people; low-quality evidence). Non-serious adverse events were mainly gastrointestinal, including diarrhoea (RR 5.76, 95% CI 2.19 to 15.15; 240 participants; low-quality evidence) and abdominal pain (RR 1.54, 95% CI 0.97 to 2.43; 294 participants; low-quality evidence).We identified one ongoing trial on terlipressin versus placebo in participants with cirrhosis, ascites, and hepatorenal syndrome type 1.Three RCTs reported funding from a pharmaceutical company. The remaining trials did not report funding or did not receive funding from pharmaceutical companies.

AUTHORS' CONCLUSIONS

This review suggests that terlipressin may be associated with beneficial effects on mortality and renal function in people with cirrhosis and type 1 hepatorenal syndrome, but it is also associated with serious adverse effects. We downgraded the strength of the evidence due to methodological issues including bias control, clinical heterogeneity, and imprecision. Consequently, additional evidence is needed.

Association Between Transjugular Intrahepatic Portosystemic Shunt and Survival in Patients With Cirrhosis

BACKGROUND & AIMS

A transjugular intrahepatic portosystemic shunt (TIPS) is an effective treatment of refractory ascites and variceal bleeding. However, it is unclear whether a TIPS affects long-term survival. We investigated whether a TIPS is associated with survival in patients with cirrhosis awaiting liver transplantation.

METHODS

By using the United Network for Organ Sharing registries from 2002 to 2013, we followed up a cohort of transplant-naive adults with cirrhosis (N = 97,063) from the time of transplant listing until the time of death or transplantation. We used Cox proportional hazards and competing-risks analyses to compare these primary outcomes between patients with a TIPS (n = 7475; 7.7%) and without a TIPS (n = 89,588; 92.3%) at the time of listing, adjusting for baseline characteristics.

RESULTS

During an average follow-up period of 1.61 years, 23,305 (24%) patients died before undergoing transplantation, 47,563 (49%) underwent transplantation, and the remaining 26,195 (27%) still were alive without having received a liver transplant. Compared with patients without a TIPS, patients with a TIPS had a lower risk of death (adjusted subhazard ratio, 0.95; 95% confidence interval, 0.9-0.99), transplantation (adjusted subhazard ratio, 0.92, 95% confidence interval, 0.88-0.95), or the combined outcome of death or transplantation (adjusted hazard ratio, 0.85; 95% confidence interval, 0.83-0.88).

CONCLUSIONS

Among patients with cirrhosis awaiting liver transplantation, patients with a TIPS had a lower mortality rate than patients without a TIPS.

Terlipressin and albumin for type 1 hepatorenal syndrome: does bacterial infection affect the response?

Vasoconstrictor therapy with terlipressin and concomitant albumin can improve renal function in patients with hepatorenal syndrome (HRS) type 1, but the efficacy of therapy in patients with active infection is controversial. The aim of this study was to investigate the efficacy, adverse effects, and predictors of terlipressin therapy and to find out whether there was a difference in response rates between the patients with or without active infections. Data of 58 patients with type 1 HRS treated with terlipressin and albumin were retrospectively evaluated. Twenty-six patients (44.8 %) showed complete response to treatment. Response rates of patients with or without active bacterial infection were 47 and 43.9 %, respectively (p > 0.05). Only baseline serum creatinine level was significantly related to response in univariate/multivariate analyses (p < 0.05). Twenty-three patients (39.6 %) developed adverse effects probably related to treatment. In 8.6 % of patients, treatment was discontinued because of adverse effects of therapy. Four patients (6.9 %) developed ischemic adverse events, including nonfatal myocardial infarction, intestinal ischemia, and cutaneous necrosis. Terlipressin plus albumin therapy improved renal function in nearly half of patients with type 1 HRS. Thus, it seems a reasonable treatment for patients with active bacterial infections. Baseline serum creatinine level is a potential predictor of terlipressin response.

[Mexican consensus on portal hypertension]

The aim of the Mexican Consensus on Portal Hypertension was to develop documented guidelines to facilitate clinical practice when dealing with key events of the patient presenting with portal hypertension and variceal bleeding. The panel of experts was made up of Mexican gastroenterologists, hepatologists, and endoscopists, all distinguished professionals. The document analyzes themes of interest in the following modules: preprimary and primary prophylaxis, acute variceal hemorrhage, and secondary prophylaxis. The management of variceal bleeding has improved considerably in recent years. Current information indicates that the general management of the cirrhotic patient presenting with variceal bleeding should be carried out by a multidisciplinary team, with such an approach playing a major role in the final outcome. The combination of drug and endoscopic therapies is recommended for initial management; vasoactive drugs should be started as soon as variceal bleeding is suspected and maintained for 5 days. After the patient is stabilized, urgent diagnostic endoscopy should be carried out by a qualified endoscopist, who then performs the corresponding endoscopic variceal treatment. Antibiotic prophylaxis should be regarded as an integral part of treatment, started upon hospital admittance and continued for 5 days. If there is treatment failure, rescue therapies should be carried out immediately, taking into account that interventional radiology therapies are very effective in controlling refractory variceal bleeding. These guidelines have been developed for the purpose of achieving greater clinical efficacy and are based on the best evidence of portal hypertension that is presently available.

Terlipressin for hepatorenal syndrome

BACKGROUND

Clinical trials suggest that terlipressin improves renal function in hepatorenal syndrome, but the evidence concerning mortality is equivocal.

OBJECTIVES

To assess the beneficial and harmful effects of terlipressin alone or with albumin versus placebo, no intervention or albumin for hepatorenal syndrome.

SEARCH METHODS

Eligible trials were identified through electronic (The Cochrane Library, MEDLINE, EMBASE and Science Citation Index databases) and manual searches until January 2012.

SELECTION CRITERIA

Randomised clinical trials involving patients with type 1 or type 2 hepatorenal syndrome were included irrespective of publication status or language.

DATA COLLECTION AND ANALYSIS

The review authors independently extracted data from trial reports and undertook correspondence with the authors. Primary outcome measures included mortality, reversal of hepatorenal syndrome and adverse events. Intention-to-treat, random-effects model meta-analyses were performed and results were expressed as risk ratios (RR) with 95% confidence intervals (CI), and the I(2) statistic provided a measure of intertrial heterogeneity. Subgroup, sensitivity, regression and sequential analyses were performed.

MAIN RESULTS

We identified six randomised clinical trials. All had high risk of bias. Five trials assessed terlipressin (with albumin in three trials) versus no intervention (with albumin in three trials) and one trial assessed terlipressin versus albumin. Data from five randomised trials on terlipressin alone (one trial) or terlipressin and albumin (four trials) were included in the review. In total, 74 of 155 (47.7%) patients randomised to terlipressin alone or terlipressin with albumin versus 98 of 154 (63.6%) patients randomised to no intervention, placebo or albumin died. Random-effects model meta-analysis found that terlipressin reduced mortality (RR 0.76, 95% CI 0.61 to 0.95). The results were stable when repeated with trials on terlipressin plus albumin, trials on patients with type 2 hepatorenal syndrome, and trials with a low risk of selection bias. No evidence of bias or small study effects were identified in regression analyses. In a trial sequential analysis on mortality, the cumulative Z curve approached but did not cross the monitoring boundary suggesting that the results were not stable to adjustment for sparse data and multiple comparisons. Analyses of the remaining outcome measures found that terlipressin and albumin increased the number of patients with reversal of hepatorenal syndrome as well as adverse events, including cardiovascular and gastrointestinal symptoms.

AUTHORS' CONCLUSIONS

Terlipressin may reduce mortality and improve renal function in patients with type 1 hepatorenal syndrome. Whether the evidence is strong enough to support the intervention for clinical practice could be debated due to the results of the trial sequential analyses. However, the outcome measures assessed are objective, which reduces the risk of bias.

Ascites: pathogenesis and therapeutic principles

Ascites is a classic complication of advanced cirrhosis and it often marks the first sign of hepatic decompensation. Ascites occurs in more than 50% of patients with cirrhosis, worsens the course of the disease, and reduces survival substantially. Portal hypertension, splanchnic vasodilatation, liver insufficiency, and cardiovascular dysfunction are major pathophysiological hallmarks. Modern treatment of ascites is based on this recognition and includes modest salt restriction and stepwise diuretic therapy with spironolactone and loop-diuretics. Tense and refractory ascites should be treated with large volume paracentesis followed by plasma volume expansion or transjugular intrahepatic portosystemic shunt. Ascites complicated by spontaneous bacterial peritonitis requires adequate treatment with antibiotics. New potential treatment strategies include the use of vasopressin V(2)-receptor antagonists and vasoconstrictors. Since formation of ascites is associated with a poor prognosis, and treatment of fluid retention does not substantially improve survival, such patients should always be considered for liver transplantation.

Systematic review of randomized trials on vasoconstrictor drugs for hepatorenal syndrome

Vasoconstrictor drugs may improve renal function in hepatorenal syndrome (HRS), but the effect on mortality has not been established. We therefore performed a systematic review of randomized trials on vasoconstrictor drugs for type 1 or type 2 HRS. Mortality was the primary outcome measure. Eligible trials were identified through electronic and manual searches. Intention-to-treat random effects meta-analyses were performed. Ten randomized trials on terlipressin alone or with albumin, octreotide plus albumin, and noradrenalin plus albumin were included. The total number of patients was 376. Overall, vasoconstrictor drugs used alone or with albumin reduced mortality compared with no intervention or albumin (relative risk [RR], 0.82; 95% confidence interval [CI], 0.70-0.96). In subgroup analyses, the effect on mortality was seen at 15 days (RR, 0.60; 95% CI, 0.37-0.97) but not at 30 days (RR, 0.74; 95% CI, 0.40-1.39), 90 days (RR, 0.89; 95% CI, 0.66-1.22), or 180 days (RR, 0.83; 95% CI, 0.65-1.05). Subgroup analyses stratified by the treatments assessed showed that terlipressin plus albumin reduced mortality compared with albumin (RR, 0.81; 95% CI, 0.68-0.97). The effect was seen in subgroup analyses of type 1 but not type 2 HRS. The remaining trials were small and found no beneficial or harmful effects of the treatments assessed.

CONCLUSION

Terlipressin plus albumin may prolong short-term survival in type 1 HRS. The duration of the response should be considered when making treatment decisions and in the timing of potential liver transplantations. Considering the small number of patients included, the evidence does not allow for treatment recommendations regarding type 2 HRS or any of the remaining treatment comparisons assessed.

Cirrhotics admitted to intensive care unit: the impact of acute renal failure on mortality

BACKGROUND

The exact role of renal dysfunction in critically ill cirrhotics admitted to an intensive care unit (ICU) has not been assessed extensively.

AIM

To evaluate the impact of acute renal failure (ARF) on 6 weeks mortality in cirrhotics admitted to ICU.

PATIENTS/METHODS

Three hundred and twelve cirrhotics (182 male, mean age 49.6+/-11.5 years) were consecutively admitted during the study period. The patients (n=128, 40%) (group 1) with ARF on admission and/or during ICU were compared with the patients whose ICU stay was not complicated with ARF (n=184, 60%) (group 2). At admission, 40 variables were available, whereas Child-Turcotte-Pugh, Model for End-stage Liver Disease, Acute Physiology and Chronic Health Evaluation II, Sequential Organ Failure Assessment and Failure Organ System scores on admission, were evaluated and compared by receiver operating characteristic curves.

RESULTS

Group 1, compared with group 2 patients, had longer ICU stay (7 vs. 4 days, P=0.04) and required cardiovascular support more frequently with inotropes (90 vs. 75%), (P<0.001). Mortality was significantly higher in group 1, compared with group 2 (91 vs. 47%, P<0.001). At admission, group 1, compared with group 2, had significantly higher Child-Turcotte-Pugh (12 vs. 11), Acute Physiology and Chronic Health Evaluation II (22 vs. 17), Model for End-stage Liver Disease (31 vs. 21), Sequential Organ Failure Assessment (13 vs. 9) and Failure Organ System (3 vs. 2) scores (P<0.001). In group 1, factors independently associated with mortality were: higher FiO2 (P=0.044), bilirubin (P=0.021) and creatinine (P=0.002) on admission. Mortality was not significantly different between those with ARF on admission, and those who developed ARF during ICU stay.

CONCLUSION

ARF at admission or during ICU stay is strongly predictive of mortality, which is high, despite supportive therapeutic interventions. Preventive measures are needed to prevent ARF, to improve prognosis.

Management of Cirrhosis and Associated Complications

Liver cirrhosis is the encapsulation or replacement of injured tissue by collagen, resulting in end-stage liver disease and portal hypertension. The consequences of cirrhosis are impaired hepatocyte function, increase intrahepatic circulatory resistance, portal hypertension, and the development of hepatocellular carcinoma. Complications include encephalopathy, coagulopathy, varices, ascites, spontaneous bacterial peritonitis, epatorenal syndrome, and hepatopulmonary syndrome. Managing patients with acute or chronic liver failure is challenging, and liver failure may have profound effects on other organ systems. Most therapies are directed at managing the complications and bridging patients to liver transplantation. The clinician must be aware of the pathologic presentations and the appropriate management, including pharmacologic and nonpharmacologic therapies, goals and end points of therapy, and monitoring of therapy. This review focuses on the management of the complications directly associated with liver dysfunction (encephalopathy and coagulopathy) and portal hypertension (varices, ascites, spontaneous bacterial peritonitis, hepatorenal syndrome, hepatopulmonary syndrome).

Pathogenetic background for treatment of ascites and hepatorenal syndrome

Ascites and hepatorenal syndrome (HRS) are the major and challenging complications of cirrhosis and portal hypertension that significantly affect the course of the disease. Liver insufficiency, portal hypertension, arterial vasodilatation, and systemic cardiovascular dysfunction are major pathophysiological hallmarks. Modern treatment of ascites is based on this recognition and includes modest salt restriction and stepwise diuretic therapy with spironolactone and loop diuretics. Tense and refractory ascites should be treated with a large volume paracentesis, followed by volume expansion or transjugular intrahepatic portosystemic shunt. New treatment strategies include the use of vasopressin V(2)-receptor antagonists and vasoconstrictors. The HRS denotes a functional and reversible impairment of renal function in patients with severe cirrhosis with a poor prognosis. Attempts of treatment should seek to improve liver function, ameliorate arterial hypotension and central hypovolemia, and reduce renal vasoconstriction. Ample treatment of ascites and HRS is important to improve the quality of life and prevent further complications, but since treatment of fluid retention does not significantly improve survival, these patients should always be considered for liver transplantation.

Management of hepatorenal syndrome

Hepatorenal syndrome is a form of acute or sub-acute renal failure which develops in patients with chronic liver disease. In contrast to other forms of acute renal failure it may be reversible using pharmacological agents. The pathogenesis involves splanchnic vasodilatation and intense renal vasoconstriction. Increasing intravascular volume and prolonged treatment with vasoconstrictor drugs reverses renal failure in a significant proportion of patients. Agents currently used include the vasopressin analogues terlipressin and the alpha1-adrenoceptor agonist midodrine. The somatostatin analogue octreotide has been used in combination therapy but is ineffective as monotherapy. Intravenous albumin is an important adjunctive treatment both in the prevention and treatment of hepatorenal syndrome. Increasing intravascular volume using TIPS (transjugular intrahepatic stent shunt) is effective in some patients and may be useful in maintaining patients who have initially responded to pharmacological therapy. Despite improvements in survival, long term prognosis is still poor and generally depends on the degree of reversibility of the underlying liver disease or access to liver transplantation.

Review article: renal function assessment in cirrhosis - difficulties and alternative measurements

BACKGROUND

Renal function in patients with cirrhosis is important prognostically, both before and following liver transplantation. Its prognostic impact is reflected by the inclusion of serum creatinine in the model for end-stage liver disease score, which is now used for recipient prioritization on liver transplantation waiting lists in the USA.

AIM

To review the accuracy of the surrogate markers for the assessment of renal function, i.e. glomerular filtration rate, particularly in patients with cirrhosis.

METHOD

We reviewed the available literature in PubMed regarding the markers for GFR evaluation and the factors which affect their accuracy in cirrhosis.

RESULTS

Although creatinine is widely available, it is an unreliable marker of glomerular filtration rate, particularly in patients with cirrhosis. Clearance of exogenous markers is considered the 'gold standard', but this methodology has many drawbacks, particularly poor applicability. Several mathematical formulae for estimated glomerular filtration rate are used to overcome some of these limitations: Cockcroft-Gault and Modification of Diet in Renal Disease formulae are the most frequently applied, but they are based on serum creatinine.

CONCLUSIONS

Due to the inaccuracy of serum creatinine and its derived formulae in estimating glomerular filtration rate, alternative serum markers, such as cystatin C, and new formulae are desirable. These need formal evaluation in patients with cirrhosis so as to have a reliable surrogate of glomerular filtration rate, and to obviate many problems that are associated with using creatinine and estimated glomerular filtration rate.

Terlipressin for hepatorenal syndrome

BACKGROUND

Terlipressin may reverse some of the circulatory changes associated with hepatorenal syndrome.

OBJECTIVES

To assess the beneficial and harmful effects of terlipressin for hepatorenal syndrome.

SEARCH STRATEGY

Electronic searches in The Cochrane Hepato-Biliary Group Controlled Trials Register, The Cochrane Renal Group Register, the Cochrane Central Register of Controlled Trials in The Cochrane Library, MEDLINE, and EMBASE were combined with scanning of bibliographies and conference proceedings, and correspondence with experts and pharmaceutical companies. Last search update was July 2006.

SELECTION CRITERIA

Randomised clinical trials were included irrespective of dose or treatment duration. Included patients had type 1 or type 2 hepatorenal syndrome. Co-interventions were allowed if administered equally to both treatment and control groups.

DATA COLLECTION AND ANALYSIS

Data were retrieved from trial reports and correspondence with the authors of included trials. Mortality was the primary outcome. Meta-analyses were performed to calculate risk differences (RD) for binary outcomes and weighted mean differences (WMD) for continuous outcomes. Both were presented with 95% confidence intervals (CI). Due to the limited number of trials, no subgroup analyses were performed.

MAIN RESULTS

The initial searches identified 645 potentially relevant references. Six randomised trials were eligible for inclusion. Three trials are still ongoing. Three trials with a total of 51 patients assessed terlipressin 1 mg bid for 2 to 15 days. Co-interventions included albumin, fresh frozen plasma, and cimetidine 800 mg daily. One trial reported adequate bias control assessed by randomisation and blinding. All trials reported mortality. Terlipressin reduced mortality rates by 34% (RD -0.34, 95% CI -0.56 to -0.12). The control group mortality rate was 65%. Terlipressin improved renal function assessed by creatinine clearance (WMD 21 ml/min, 95% CI 17 to 26), serum creatinine (WMD -219 micromol/l, 95% CI -244 to -194), and urine output (WMD 707 ml/day, 95% CI -212 to 1625). Adverse events included headache, abdominal pain, cardiac arrhythmia, and hypertension.

AUTHORS' CONCLUSIONS

Additional evidence on terlipressin for hepatorenal syndrome is needed before reliable treatment recommendations can be made. The dose and duration of therapy, and the influence of co-interventions remain to be established.

Transhepatic puncture of portal and hepatic veins for TIPS using a single-needle pass under sonographic guidance

OBJECTIVE

Creating transjugular intrahepatic portosystemic shunts (TIPS) requires accessing a portal vein branch from a metal cannula wedged in a hepatic vein. This initial step in shunt creation often requires multiple blind intrahepatic punctures and occasionally fails. We describe a method using sonographic guidance to serially puncture the portal vein and hepatic vein with a single transhepatic needle pass, after which the TIPS procedure is completed in the standard transjugular fashion.

CONCLUSION

Sonographically guided transhepatic dual puncture of the portal and hepatic veins facilitates portosystemic shunt creation in a single needle pass and allows more controlled selection of the portal vein entry and hepatic vein landing sites in selected patients.

Determinants of the renin-angiotensin-aldosterone system in cirrhosis with special emphasis on the central blood volume

OBJECTIVE

Several studies have shown activation of the renin-angiotensin-aldosterone system (RAAS) in cirrhosis. Although the activated RAAS may have several determinants, the system is often considered a surrogate marker of effective hypovolaemia. In this study we investigated the activity of the RAAS and its potential determinants with special focus on the central and arterial blood volume (CBV).

MATERIAL AND METHODS

Eighty-nine patients (Child class A/B/C: 19/41/29) and 32 controls were included in the study. All were given a haemodynamic examination with measurement of determinants of the RAAS, including the CBV. Circulating plasma renin concentrations were measured using an immunoradiometric assay.

RESULTS

Arterial renin concentrations were significantly higher in the patients than in the controls (p < 0.003). Plasma renin correlated significantly with several indicators of liver dysfunction and splanchnic and systemic haemodynamics (r = - 0.56-0.55), but only weakly with CBV (r = - 0.25, p < 0.02). In a multivariate regression analysis, plasma renin was determined by serum sodium, alkaline phosphatases and systolic blood pressure (p < 0.04 to p < 0.001).

CONCLUSIONS

CBV correlates weakly with circulating renin, and activation of the RAAS can therefore only partly be considered as an indicator of central hypovolaemia. Mechanisms other than central hypovolaemia relating to the liver disease and portal hypertension contribute significantly to the RAAS activation.

Cardiopulmonary complications in chronic liver disease

Patients with cirrhosis and portal hypertension exhibit characteristic cardiovascular and pulmonary hemodynamic changes. A vasodilatatory state and a hyperdynamic circulation affecting the cardiac and pulmonary functions dominate the circulation. The recently defined cirrhotic cardiomyopathy may affect systolic and diastolic functions, and imply electromechanical abnormalities. In addition, the baroreceptor function and regulation of the circulatory homoeostasis is impaired. Pulmonary dysfunction involves diffusing abnormalities with the development of the hepatopulmonary syndrome and portopulmonary hypertension in some patients. Recent research has focused on the assertion that the hemodynamic and neurohumoral dysregulation are of major importance for the development of the cardiovascular and pulmonary complications in cirrhosis. This aspect is important to take into account in the management of these patients.

Contrast nephropathy may be partly mediated by autonomic dysfunction: renal failure considered as a modern maladaptation of the prehistoric trauma response

The mechanism behind iodinated radiocontrast nephropathy remains elusive. Direct oxidative damage is the prevailing hypothesis, but the apparent protective effect of iodine against oxidation contradicts this view. We propose that autonomic dysfunction participates in the pathogenesis of radiocontrast nephropathy and may account for other contrast-associated reactions previously attributed to allergy. Iodine, through its effects on thyroid function and chemoreceptor response to metabolic acidosis, may induce hyperadrenergia and consequently diminish renovascular flow and urine output. The renal response to adrenergia likely served an adaptive function during prehistoric evolution when trauma was a dominant source of hypovolemia and adrenergia, but the response may behave maladaptively today as evolutionarily nai ve triggers for adrenergia have emerged. Autonomic dysfunction can further impair renal function by deranging renovascular autoregulation and inducing oxidative reperfusion injury as a secondary phenomenon. Many other causes of acute renal failure such as drug toxicity, surgery, hospitalization, and diabetes may operate through hyperadrenergia, impaired renovascular autoregulation, and oxidative reperfusion injury. Dialysis, a volume reduction therapy for renal failure, can counterintuitively worsen renal dysfunction by exacerbating adrenergia, which may explain its association with accelerated atherosclerosis, inflammation, and cancer. Other examples of vicious cycles that perpetuate renal dysfunction may include renal artery stenosis, carotid stenosis, and atherosclerosis as well as the cardio-renal, hepato-renal, and pulmonary-renal syndromes. The benefits of hydration and bicarbonate in protecting renal function may operate in part through baroreceptor- and chemoreceptor-mediated reduction of sympathovagal ratio, respectively. New treatment paradigms for renal failure including pharmacologic and electro-mechanical therapies are envisioned based on autonomic remodeling, reduced sympathovagal ratio, and neuromodulation of pathways typically associated with trauma such as renin, angiotensin, vasopressin, and aldosterone.

Uncovered transjugular intrahepatic portosystemic shunt for refractory ascites: a meta-analysis

BACKGROUND & AIMS

Several trials showed that uncovered transjugular intrahepatic portosystemic shunt (TIPS) is superior to paracentesis for the control of refractory ascites. However, the results for encephalopathy and mortality were not consistent across trials. We performed a systematic review of randomized controlled trials of TIPS for refractory ascites to assess the overall treatment effects and to explore potential reasons of heterogeneity.

METHODS

Pertinent studies were retrieved trough MEDLINE (1968-2004), EMBASE (1986-2004), the Cochrane Library (2004;4), and reference lists of key articles. Outcome measures were recurrence of ascites, encephalopathy, and mortality. Metaregression analysis was used to explore heterogeneity.

RESULTS

Five trials were identified including 330 patients. Successful TIPS placement ranged from 77% to 100% and portosystemic pressure gradient reduction ranged from 6.0 to 14.0 mm Hg. Metaregression analysis showed that bilirubin levels and successful TIPS placement rates were associated significantly with log-odds ratio for death after TIPS, explained heterogeneity of trials for mortality, and suggested an outlier trial. After exclusion of the outlier trial, pooled odds ratios for recurrence of ascites with TIPS was .14 (confidence interval, .07-.27), for encephalopathy was 2.26 (confidence interval, 1.35-3.76), and for mortality was .74 (confidence interval, .40-1.37), without any significant heterogeneity.

CONCLUSIONS

Uncovered TIPS is significantly better than paracentesis for control of refractory ascites. Although it increases encephalopathy, it also is associated with a trend toward improvement of survival. Future TIPS trials should select patients on the basis of bilirubin levels and predictors of the risk for post-TIPS encephalopathy, and assess costs and quality of life.