Prognostic Role of Ammonia in Patients With Cirrhosis

Overt hepatic encephalopathy is an independent risk factor for de novo infection in cirrhotic patients with acute decompensation

BACKGROUND

The occurrence of overt hepatic encephalopathy (OHE) is associated with increased mortality. HE is commonly precipitated by infection, but whether HE predisposes to new infection is unclear. This study aimed to test if OHE predisposes to de novo infection during hospitalisation and its association with short-term mortality.

AIMS AND METHODS

Seven hundred and fifty-nine consecutive patients were identified at two institutions from prospectively maintained clinical databases of cirrhotic patients admitted with acute decompensation (AD). Infection and HE data were collected on the day of admission, and the occurrence of de novo infections was assessed for 28 days after admission. EASL-CLIF organ failure criteria were used to determine the presence of organ failures. Multivariable analysis using the logistic regression model was used to assess predictors of 28-day mortality and de novo infection.

RESULTS

Patients were divided into four groups; no baseline OHE or infection (n = 352); OHE with no baseline Infection (n = 221); no OHE but baseline infection (n = 100) and OHE with baseline infection (n = 86). On multivariate analyses, OHE (OR, 1.532 [95% CI, 1.061-2.300, P = 0.024]), and admission to ITU (OR, 2.303 [95% CI, 1.508-3.517, P < 0.001]) were independent risk factors for de novo infection. 28-day mortality was 25.3%, 60.2%, 55.0% and 72.1% in the 4-groups respectively. Age, INR and creatinine were independently predictive of mortality. The presence of overt HE, infection, coagulation, kidney, circulatory, respiratory and liver failures were significantly associated with higher mortality.

CONCLUSION

OHE is an independent risk factor for de novo infection in cirrhotic patients with AD.

Insight into microRNAs-Mediated Communication between Liver and Brain: A Possible Approach for Understanding Acute Liver Failure?

Acute liver failure (ALF) is a life-threatening consequence of hepatic function rapid loss without preexisting liver disease. ALF may result in a spectrum of neuropsychiatric symptoms that encompasses cognitive impairment, coma, and often death, collectively defined as acute hepatic encephalopathy. Micro RNAs are small non-coding RNAs that modulate gene expression and are extensively verified as biomarker candidates in various diseases. Our systematic literature review based on the last decade's reports involving a total of 852 ALF patients, determined 205 altered circulating miRNAs, of which 25 miRNAs were altered in the blood, regardless of study design and methodology. Selected 25 miRNAs, emerging predominantly from the analyses of samples obtained from acetaminophen overdosed patients, represent the most promising biomarker candidates for a diagnostic panel for symptomatic ALF. We discussed the role of selected miRNAs in the context of tissue-specific origin and its possible regulatory role for molecular pathways involved in blood-brain barrier function. The defined several common pathways for 15 differently altered miRNAs were relevant to cellular community processes, indicating loss of intercellular, structural, and functional components, which may result in blood-brain barrier impairment and brain dysfunction. However, a causational relationship between circulating miRNAs differential expression, and particular clinical features of ALF, has to be demonstrated in a further study.

Mitochondrial Dysfunction in Advanced Liver Disease: Emerging Concepts

Mitochondria are entrusted with the challenging task of providing energy through the generation of ATP, the universal cellular currency, thereby being highly flexible to different acute and chronic nutrient demands of the cell. The fact that mitochondrial diseases (genetic disorders caused by mutations in the nuclear or mitochondrial genome) manifest through a remarkable clinical variation of symptoms in affected individuals underlines the far-reaching implications of mitochondrial dysfunction. The study of mitochondrial function in genetic or non-genetic diseases therefore requires a multi-angled approach. Taking into account that the liver is among the organs richest in mitochondria, it stands to reason that in the process of unravelling the pathogenesis of liver-related diseases, researchers give special focus to characterizing mitochondrial function. However, mitochondrial dysfunction is not a uniformly defined term. It can refer to a decline in energy production, increase in reactive oxygen species and so forth. Therefore, any study on mitochondrial dysfunction first needs to define the dysfunction to be investigated. Here, we review the alterations of mitochondrial function in liver cirrhosis with emphasis on acutely decompensated liver cirrhosis and acute-on-chronic liver failure (ACLF), the latter being a form of acute decompensation characterized by a generalized state of systemic hyperinflammation/immunosuppression and high mortality rate. The studies that we discuss were either carried out in liver tissue itself of these patients, or in circulating leukocytes, whose mitochondrial alterations might reflect tissue and organ mitochondrial dysfunction. In addition, we present different methodological approaches that can be of utility to address the diverse aspects of hepatocyte and leukocyte mitochondrial function in liver disease. They include assays to measure metabolic fluxes using the comparatively novel Biolog’s MitoPlates in a 96-well format as well as assessment of mitochondrial respiration by high-resolution respirometry using Oroboros’ O2k-technology and Agilent Seahorse XF technology.

Role of lactulose for prophylaxis against hepatic encephalopathy in cirrhotic patients with upper gastrointestinal bleeding: A randomized trial

BACKGROUND

We aimed to assess the efficacy of lactulose as prophylaxis against hepatic encephalopathy (HE) in cirrhotic patients with acute upper gastrointestinal bleeding (AUGIB).

METHODS

We conducted a randomized, double-blinded, placebo-controlled, multicenter study from October 2012 to February 2014. Cirrhotic patients presenting with AUGIB (aged 18-80 years, without HE at the time of admission) were enrolled and randomized to receive blinded medications (both physically indistinguishable), labeled "Lactulose A" and "Lactulose B" for 5 days along with standard treatment depending on the type of bleeding (variceal and nonvariceal). The primary endpoint was the development of overt HE according to the West-Haven criteria. Modified intention-to-treat analysis was performed.

RESULTS

Forty-six patients completed the protocol: Lactulose A (placebo, n = 22) and Lactulose B (lactulose, n = 24). There was no significant difference in baseline characteristics and clinical outcomes between the two groups. Nine (19.6%) patients developed HE: five (22.7%) in the placebo group and four (16.7%) in the lactulose group (p = 0.718). One patient (2.2%) died in lactulose group. All patients tolerated the medication and no significant difference in adverse effects was detected (59.1% in placebo vs. 50.0% in lactulose group, p = 0.536). On multivariate analysis, increased baseline Child-Turcotte-Pugh (CTP) score (odds ratio [OR] 2.176; 95% confidence interval [CI] 1.012-4.681, p = 0.047) and presence of diarrhea (OR 16.261; 95% CI 1.395-189.608, p = 0.026) were independent risk factors for the development of HE.

CONCLUSION

Five-day lactulose is ineffective as prophylaxis against HE in cirrhotic patients with AUGIB. Unnecessary treatment with laxatives should be avoided in these patients.

TRIAL REGISTRATION

Clinical trial registry number TCTR20200526003 (retrospectively registered).

Optimization of an ammonia assay based on transmembrane pH-gradient polymersomes

Reliable ammonia quantification assays are essential for monitoring ammonemia in patients with liver diseases. In this study, we describe the development process of a microplate-based assay for accurate, precise, and robust ammonia quantification in biological fluids, following regulatory guidelines on bioanalytical method validation. The assay is based on transmembrane pH-gradient polymersomes that encapsulate a pH-sensitive ratiometric fluorophore, the fluorescence signal of which correlates with the ammonia concentration in the sample. Using a four-parameter logistic regression, the assay had a large quantification range (30–800 μM ammonia). As for selectivity, the presence of amino acids or pyruvate (up to clinically relevant concentrations) showed no assay interference. In samples with low bilirubin levels, polymersomes containing the fluorophore pyranine provided accurate ammonia quantification. In samples with high bilirubin concentrations, billirubin’s optical interference was alleviated when replacing pyranine with a close to near-infrared hemicyanine fluorophore. Finally, the assay could correctly retrieve the ammonia concentration in ammonia-spiked human plasma samples, which was confirmed by comparing our measurements with the data obtained using a commercially available point-of-care device for ammonia.

Impact of non-hepatic hyperammonemia on mortality in intensive care unit patients: a retrospective cohort study

BACKGROUND/AIMS

The effect of hyperammonemia on the mortality in patients with liver cirrhosis is well documented. However, little is known about the impact of hyperammonemia on mortality among intensive care unit patients without hepatic disease. We aimed to investigate factors associated with non-hepatic hyperammonemia among intensive care unit patients and to evaluate the factors related to the 7- and 90-day mortality.

METHODS

Between February 2016 and February 2020, 948 patients without hepatic disease who had 972 episodes of admission to the intensive care unit were retrospectively enrolled and classified as hyperammonemia grades 0 (≤ 80 µg/dL; 585 [60.2%]), 1 (≤ 160 µg/dL; 291 [29.9%]), 2 (≤ 240 µg/dL; 55 [5.7%]), and 3 (> 240 µg/dL; 41 [4.2%]). Factors associated with hyperammonemia and the 7- and 90-day mortality were evaluated by multivariate logistic regression analysis and Cox regression analysis, respectively. Kaplan-Meier survival curves for the 7- and 90-day mortality were constructed.

RESULTS

The independent risk factors for hyperammonemia were male sex (odds ratio, 1.517), age (0.984/year), acute brain failure (2.467), acute kidney injury (1.437), prothrombin time-international normalized ratio (2.272/unit), and albumin (0.694/g/dL). The 90-day mortality rate in the entire cohort was 24.3% and gradually increased with increasing hyperammonemia grade at admission (17.9%, 28.2%, 43.6%, and 61.0% in patients with grades 0, 1, 2, and 3, respectively). Additionally, non-hepatic hyperammonemia was an independent predictor of the 90- day mortality in intensive care unit patients.

CONCLUSION

Non-hepatic hyperammonemia is common (39.8%) and associated with the 90-day mortality among intensive care unit patients.

Hepatic Encephalopathy: From Metabolic to Neurodegenerative

Hepatic encephalopathy (HE) is a neuropsychiatric syndrome of both acute and chronic liver disease. As a metabolic disorder, HE is considered to be reversible and therefore is expected to resolve following the replacement of the diseased liver with a healthy liver. However, persisting neurological complications are observed in up to 47% of transplanted patients. Several retrospective studies have shown that patients with a history of HE, particularly overt-HE, had persistent neurological complications even after liver transplantation (LT). These enduring neurological conditions significantly affect patient's quality of life and continue to add to the economic burden of chronic liver disease on health care systems. This review discusses the journey of the brain through the progression of liver disease, entering the invasive surgical procedure of LT and the conditions associated with the post-transplant period. In particular, it will discuss the vulnerability of the HE brain to peri-operative factors and post-LT conditions which may explain non-resolved neurological impairment following LT. In addition, the review will provide evidence; (i) supporting overt-HE impacts on neurological complications post-LT; (ii) that overt-HE leads to permanent neuronal injury and (iii) the pathophysiological role of ammonia toxicity on astrocyte and neuronal injury/damage. Together, these findings will provide new insights on the underlying mechanisms leading to neurological complications post-LT.

The neurogliovascular unit in hepatic encephalopathy

Hepatic encephalopathy (HE) is a neurological complication of hepatic dysfunction and portosystemic shunting. It is highly prevalent in patients with cirrhosis and is associated with poor outcomes. New insights into the role of peripheral origins in HE have led to the development of innovative treatment strategies like faecal microbiota transplantation. However, this broadening of view has not been applied fully to perturbations in the central nervous system. The old paradigm that HE is the clinical manifestation of ammonia-induced astrocyte dysfunction and its secondary neuronal consequences requires updating. In this review, we will use the holistic concept of the neurogliovascular unit to describe central nervous system disturbances in HE, an approach that has proven instrumental in other neurological disorders. We will describe HE as a global dysfunction of the neurogliovascular unit, where blood flow and nutrient supply to the brain, as well as the function of the blood-brain barrier, are impaired. This leads to an accumulation of neurotoxic substances, chief among them ammonia and inflammatory mediators, causing dysfunction of astrocytes and microglia. Finally, glymphatic dysfunction impairs the clearance of these neurotoxins, further aggravating their effect on the brain. Taking a broader view of central nervous system alterations in liver disease could serve as the basis for further research into the specific brain pathophysiology of HE, as well as the development of therapeutic strategies specifically aimed at counteracting the often irreversible central nervous system damage seen in these patients.

Lactate and blood ammonia on admission as biomarkers to predict the prognosis of patients with acute mushroom poisoning and liver failure: a retrospective study

The diagnosis of liver damage induced by mushroom poisoning is still challenging. This study aims to screen the early biological indexes that could predict acute mushroom poisoning with liver damage. The patients with acute mushroom poisoning and liver damage admitted to The First Affiliated Hospital of Dalian Medical University，China from July 2007 to August 2017 were analyzed retrospectively. A total of 66 patients were enrolled in this study, with 44 and 22 patients in the liver injury group and liver failure group, respectively. Ten patients in the liver failure group died, with a mortality of 45.5% in this group. Multivariable Cox regression showed that the blood ammonia (NH3) and lactic acid (Lac) at the time of admission were independently associated with the in-hospital time to death for patients with liver failure induced by mushroom poisoning. Lactate and blood ammonia at the time of admission could be used to predict the prognosis of patients with acute mushroom poisoning and liver failure.

Minimal portosystemic encephalopathy: A new nosological entity in patients with hereditary haemorrhagic telangiectasia

BACKGROUND

Portosystemic shunts in Hereditary Haemorrhagic Telangiectasia (HHT) are often overlooked by conventional imaging although they could reduce hepatic clearance of gut-derived toxins.

AIMS

To evaluate, the presence of subclinical neurological alterations (SNAs), that we named "minimal portosystemic encephalopathy" (mPSE) in HHT patients without advanced liver disease (ALD).

METHODS

In this cross sectional study, consecutive HHT outpatients were firstly screened by critical flicker frequency (CFF) test (abnormal ≤39Hz), and the simplified animal naming test (S-ANT₁) (abnormal <15) was used to confirm the diagnosis of mPSE. Furthermore, we evaluated the effect of lactulose administration on mPSE. Multi-slice CT, cerebral dynamic magnetic resonance, laboratory analyses and transient elastography were also used.

RESULTS

None of the 37 enrolled patients showed portosystemic shunts at imaging techniques. However, 33 patients had normal CFF values (CFF-) and 4 displayed CFF alterations (37.0±0.7Hz, CFF+). The S-ANT₁ confirmed an impaired neurological performance (10.2±2.8) in CFF+ patients thus confirming the presence of mPSE. Noteworthy, lactulose administration determined a CFF increase (39.1±0.4Hz) and S-ANT₁ normalization in these patients. Neither mPSE- nor mPSE+ patients had ALD and showed similar demographic, clinical and laboratory parameters. Finally, no mPSE+ patient showed radiologically-detectable brain vascular malformations or other brain abnormalities at imaging.

CONCLUSIONS

HHT patients represent a human model of mPSE secondary to portosystemic shunts escaping radiological detection. mPSE evaluation should be incorporated in HHT surveillance protocols since it can affect both health-related/social aspects and pharmacokinetics of orally administered drugs with a narrow therapeutic index and high hepatic first-pass uptake.

Dynamic assessments of hepatic encephalopathy and ammonia levels predict mortality in acute-on-chronic liver failure

BACKGROUND

We evaluated the dynamics of hepatic encephalopathy (HE) and ammonia estimation in acute-on-chronic liver failure (ACLF) patients due to a paucity of evidence.

METHODS

ACLF patients recruited from the APASL-ACLF Research Consortium (AARC) were followed up till 30 days, death or transplantation, whichever earlier. Clinical details, including dynamic grades of HE and laboratory data, including ammonia levels, were serially noted.

RESULTS

Of the 3009 ACLF patients, 1315 (43.7%) had HE at presentation; grades I-II in 981 (74.6%) and grades III-IV in 334 (25.4%) patients. The independent predictors of HE at baseline were higher age, systemic inflammatory response, elevated ammonia levels, serum protein, sepsis and MELD score (p < 0.05; each). The progressive course of HE was noted in 10.0% of patients without HE and 8.2% of patients with HE at baseline, respectively. Independent predictors of progressive course of HE were AARC score (≥ 9) and ammonia levels (≥ 85 μmol/L) (p < 0.05; each) at baseline. A final grade of HE was achieved within 7 days in 70% of patients and those with final grades III-IV had the worst survival (8.9%). Ammonia levels were a significant predictor of HE occurrence, higher HE grades and 30-day mortality (p < 0.05; each). The dynamic increase in the ammonia levels over 7 days could predict nonsurvivors and progression of HE (p < 0.05; each). Ammonia, HE grade, SIRS, bilirubin, INR, creatinine, lactate and age were the independent predictors of 30-day mortality in ACLF patients.

CONCLUSIONS

HE in ACLF is common and is associated with systemic inflammation, poor liver functions and high disease severity. Ammonia levels are associated with the presence, severity, progression of HE and mortality in ACLF patients.

Pathophysiology of decompensated cirrhosis: Portal hypertension, circulatory dysfunction, inflammation, metabolism and mitochondrial dysfunction

Patients with acutely decompensated cirrhosis have a dismal prognosis and frequently progress to acute-on-chronic liver failure, which is characterised by hepatic and extrahepatic organ failure(s). The pathomechanisms involved in decompensation and disease progression are still not well understood, and as specific disease-modifying treatments do not exist, research to identify novel therapeutic targets is of the utmost importance. This review amalgamates the latest knowledge on disease mechanisms that lead to tissue injury and extrahepatic organ failure - such as systemic inflammation, mitochondrial dysfunction, oxidative stress and metabolic changes - and marries these with the classical paradigms of acute decompensation to form a single paradigm. With this detailed breakdown of pathomechanisms, we identify areas for future research. Novel disease-modifying strategies that break the vicious cycle are urgently required to improve patient outcomes.

Hyperammonemia in acetaminophen toxicity

INTRODUCTION

Acetaminophen-induced hepatotoxicity can result in hyperammonemia, but it is not clear if elevated ammonia concentrations predict encephalopathy.

METHODS

We retrospectively studied patients with acetaminophen toxicity at a liver transplant center over 8 years (January 1, 2010-December 31, 2017), who developed hepatotoxicity (AST and/or ALT >1000 IU/L) or hyperammonemia (ammonia > 40 µmol/L). We recorded baseline characteristics, laboratory data, documented grade of encephalopathy, and treatments administered. Sensitivity and specificity values were calculated for varying ammonia concentrations.

RESULTS

A total of 102 patient encounters were included with 75 having ammonia concentrations. On presentation, 40% (30/75) of patients had concentrations greater than 100 µmol/L. However, an [ammonia] > 100 µmol/L was neither sensitive (46 % [95% CI: 26-67%]) nor specific (63% [48 - 76%]) for encephalopathy. Only an increasing ammonia concentration had a significant, but small (1.53 (95% CI: 1.06 - 2.20)) positive likelihood ratio for the development of hepatic encephalopathy.

DISCUSSION

Animal models have suggested that in acetaminophen toxicity, encephalopathy may be secondary to an alternative mechanism other than hyperammonemia which may explain the lack of correlation between initial hyperammonemia and encephalopathy in this cohort. Additionally, a lack of empiric treatment for hyperammonemia did not appear to alter the course of any of the patients. None of these patients developed encephalopathy.

CONCLUSION

In cases of acetaminophen-induced hepatotoxicity, ammonia concentrations do not correlate with encephalopathy and empiric treatment for hyperammonemia does not appear to be beneficial.

Diagnosis and Management of Hepatic Encephalopathy

Hepatic encephalopathy (HE) is a severe complication of cirrhosis. The prevalence of overt HE (OHE) ranges from 30% to 45%, whereas the prevalence of minimal HE (MHE) is as high as 85% in some case series. Widespread use of transjugular intrahepatic portosystemic shunt to control complications related to portal hypertension is associated with an increase in HE incidence. If the diagnosis of OHE remains simple in most cases, then the diagnosis of MHE is less codified because of many differential diagnoses with different therapeutic implications. This review analyzes current knowledge about the pathophysiology, diagnosis, and different therapeutic options of HE.

Enhanced Meningeal Lymphatic Drainage Ameliorates Neuroinflammation and Hepatic Encephalopathy in Cirrhotic Rats

BACKGROUND & AIMS

Hepatic encephalopathy (HE) is a serious neurologic complication in patients with liver cirrhosis. Very little is known about the role of the meningeal lymphatic system in HE. We tested our hypothesis that enhancement of meningeal lymphatic drainage could decrease neuroinflammation and ameliorate HE.

METHODS

A 4-week bile duct ligation model was used to develop cirrhosis with HE in rats. Brain inflammation in patients with HE was evaluated by using archived GSE41919. The motor function of rats was assessed by the rotarod test. Adeno-associated virus 8-vascular endothelial growth factor C (AAV8-VEGF-C) was injected into the cisterna magna of HE rats 1 day after surgery to induce meningeal lymphangiogenesis.

RESULTS

Cirrhotic rats with HE showed significantly increased microglia activation in the middle region of the cortex (P < .001) as well as increased neuroinflammation, as indicated by significant increases in interleukin 1β, interferon γ, tumor necrosis factor α, and ionized calcium binding adaptor molecule 1 (Iba1) expression levels in at least 1 of the 3 regions of the cortex. Motor function was also impaired in rats with HE (P < .05). Human brains of patients with cirrhosis with HE also exhibited up-regulation of proinflammatory genes (NFKB1, IbA1, TNF-α, and IL1β) (n = 6). AAV8-VEGF-C injection significantly increased meningeal lymphangiogenesis (P = .035) and tracer dye uptake in the anterior and middle regions of the cortex (P = .006 and .003, respectively), their corresponding meninges (P = .086 and .006, respectively), and the draining lymph nodes (P = .02). Furthermore, AAV8-VEGF-C decreased microglia activation (P < .001) and neuroinflammation and ameliorated motor dysfunction (P = .024).

CONCLUSIONS

Promoting meningeal lymphatic drainage and enhancing waste clearance improves HE. Manipulation of meningeal lymphangiogenesis could be a new therapeutic strategy for the treatment of HE.

Role of ammonia in predicting the outcome of patients with acute-on-chronic liver failure

BACKGROUND

High venous ammonia (VA) values have been proven to be a part of the mechanism of hepatic encephalopathy in patients with liver cirrhosis (LC) as well as acute hepatitis. Moreover, VA has been associated with poor prognosis and high mortality in these clinical settings. However, the role of ammonia in acute-on-chronic liver failure (ACLF) has not yet been clearly established.

AIM

To assess the role of VA in predicting the outcome of cirrhotic patients with ACLF in a tertiary care center.

METHODS

We performed a retrospective observational study including consecutive patients with LC hospitalized for acute non-elective indications such as ascites, hepatic encephalopathy (HE), upper gastrointestinal bleeding, or bacterial infections that fulfilled the Asian Pacific Association for the Study of the Liver (APASL) criteria for ACLF. The study was conducted in “St. Spiridon” University Hospital, Iasi, Romania, a tertiary care center, between January 2017 and January 2019. The APASL ACLF Research Consortium (AARC) score was calculated and ACLF grade was established accordingly. West-haven classification was used for HE. Statistical analysis was performed using IBM SPSS version 22.0.

RESULTS

Four hundred and forty-six patients were included, aged 59 (50-65) years, 57.4% men. Child-Pugh, model for end-stage liver disease (MELD) and AARC scores were 11 (10-12), 19.13 ± 6.79, and 7 (6-8), respectively. 66.4% had ACLF grade I, 31.2% ACLF grade II, and 2.5% ACLF grade III. HE was diagnosed in 83.9%, 34% grade I, 37.2% grade II, 23.5% grade III, and 5.3% grade IV. Overall mortality was 7.8%. VA was 103 (78-148) μmol/L. Receiver operating characteristic analysis showed good accuracy for the prediction of in-hospital mortality for the AARC score [Area under the curve (AUC) = 0.886], MELD score (AUC = 0.816), VA (AUC = 0.812) and a fair accuracy for the Child-Pugh score (AUC = 0.799). Subsequently, a cut-off value for the prediction of mortality was identified for VA (152.5 μmol/L, sensitivity = 0.706, 1-specificity = 0.190). Univariate analysis found acute kidney injury, severe HE (grade III or IV), VA ≥ 152.5 μmol/L, MELD score ≥ 22.5, Child-Pugh score ≥ 12.5, and AARC score ≥ 8.5 to be associated with in-hospital mortality. Multivariate analysis identified AARC score ≥ 8.5 and venous ammonia ≥ 152 μmol/L to be independent predictors of in-hospital mortality.

CONCLUSION

VA could be used as an inexpensive predictor of in-hospital mortality in patients with ACLF. Patients with both ACLF and VA > 152.5 μmol/L have a high risk for a poor outcome.

Lights and Shadows in Hepatic Encephalopathy Diagnosis

Hepatic encephalopathy (HE) is a form of brain dysfunction that is caused by liver insufficiency and/or portal-systemic shunting. The exact nature of HE is debated; as such, conflicting uses of the term "HE" may cause inconsistencies in its detection and management. This review highlights the meaning of the term "HE" on the basis of its historical origins and current consensus. It also provides criteria for the diagnosis of the condition based on its phenotypes and risk factors for its occurrence. The procedure for differential diagnosis from other conditions which result in similar phenotypes is considered, together with precipitants and confounders. Finally, the current multidimensional approach for the correct clinical reporting of HE episodes is discussed.

Determinants of mortality in patients with cirrhosis and uncontrolled variceal bleeding

BACKGROUND & AIMS

Failure to control oesophago-gastric variceal bleeding (OGVB) and acute-on-chronic liver failure (ACLF) are both important prognostic factors in cirrhosis. The aims of this study were to determine whether ACLF and its severity define the risk of death in OGVB and whether insertion of rescue transjugular intrahepatic shunt (TIPS) improves survival in patients with failure to control OGVB and ACLF.

METHODS

Data on 174 consecutive eligible patients, with failure to control OGVB between 2005 and 2015, were collected from a prospectively maintained intensive care unit registry. Rescue TIPS was defined as technically successful TIPS within 72 hours of presentation with failure to control OGVB. Cox-proportional hazards regression analyses were applied to explore the impact of ACLF and TIPS on survival in patients with failure to control OGVB.

RESULTS

Patients with ACLF (n = 119) were significantly older, had organ failures and higher white cell count than patients with acute decompensation (AD, n = 55). Mortality at 42-days and 1-year was significantly higher in patients with ACLF (47.9% and 61.3%) than in those with AD (9.1% and 12.7%, p <0.001), whereas there was no difference in the number of endoscopies and transfusion requirements between these groups. TIPS was inserted in 78 patients (AD 21 [38.2%]; ACLF 57 [47.8%]; p = 0.41). In ACLF, rescue TIPS insertion was an independent favourable prognostic factor for 42-day mortality. In contrast, rescue TIPS did not impact on the outcome of patients with AD.

CONCLUSIONS

This study shows that in patients with failure to control OGVB, the presence and severity of ACLF determines the risk of 42-day and 1-year mortality. Rescue TIPS is associated with improved survival in patients with ACLF.

LAY SUMMARY

Variceal bleeding that is not controlled by initial endoscopy is associated with high risk of death. The results of this study showed that in the occurrence of failure of the liver and other organs defines the risk of death. In these patients, insertion of a shunt inside the liver to drain the portal vein improves survival.

Endpoints and design of clinical trials in patients with decompensated cirrhosis: Position paper of the LiverHope Consortium

Management of decompensated cirrhosis is currently geared towards the treatment of complications once they occur. To date there is no established disease-modifying therapy aimed at halting progression of the disease and preventing the development of complications in patients with decompensated cirrhosis. The design of clinical trials to investigate new therapies for patients with decompensated cirrhosis is complex. The population of patients with decompensated cirrhosis is heterogeneous (i.e., different etiologies, comorbidities and disease severity), leading to the inclusion of diverse populations in clinical trials. In addition, primary endpoints selected for trials that include patients with decompensated cirrhosis are not homogeneous and at times may not be appropriate. This leads to difficulties in comparing results obtained from different trials. Against this background, the LiverHope Consortium organized a meeting of experts, the goal of which was to develop recommendations for the design of clinical trials and to define appropriate endpoints, both for trials aimed at modifying the natural history and preventing progression of decompensated cirrhosis, as well as for trials aimed at managing the individual complications of cirrhosis.

Increasing serum ammonia level is a risk factor for the prognosis of critically ill patients: A multicenter retrospective cohort study

PURPOSE

To assess the association between serum ammonia level upon admission during the initial intensive care unit (ICU) stay and mortality.

MATERIALS AND METHODS

This retrospective cohort study included 2703 adult patients in eICU Collaborative Research Database. The ICU mortality within ammonia deciles were assessed. Logistic regression analyses were performed to analyze the relationship between ammonia and mortality.

RESULTS

We defined three ammonia categories: <47, 47-111, and ≥111 μg/dL, corresponding to low, intermediate, and high ICU mortality. Increased ammonia was significantly associated with increased ICU mortality (per 10 μg/dL increase: odds ratio, 1.070 [95% confidence intervals, 1.05-1.09]; intermediate vs. low: 1.90 [1.41-2.56]; high vs. low: 4.38 [2.99-6.41]) and in-hospital mortality (1.06 [1.04-1.08]; 1.45 [1.13-1.87]; 3.41 [2.43-4.79]). Adding ammonia to the Acute Physiology and Chronic Health Evaluation (APACHE) IV score improved the area under the curve from 0.826 to 0.839 (P < 0.001) and from 0.806 to 0.813 (P = 0.001) for ICU and in-hospital mortality, respectively. Interaction and subgroup analyses demonstrated consistent results in patients with different APACHE IV scores, with or without hepatic diseases.

CONCLUSIONS

Elevated serum ammonia level in critically ill patients upon admission was an early risk factor for higher ICU and in-hospital mortality.

Hepatic encephalopathy: Novel insights into classification, pathophysiology and therapy

Hepatic encephalopathy (HE) is a frequent and serious complication of both chronic liver disease and acute liver failure. HE manifests as a wide spectrum of neuropsychiatric abnormalities, from subclinical changes (mild cognitive impairment) to marked disorientation, confusion and coma. The clinical and economic burden of HE is considerable, and it contributes greatly to impaired quality of life, morbidity and mortality. This review will critically discuss the latest classification of HE, as well as the pathogenesis and pathophysiological pathways underlying the neurological decline in patients with end-stage liver disease. In addition, management strategies, diagnostic approaches, currently available therapeutic options and novel treatment strategies are discussed.

Serum ammonia is a strong prognostic factor for patients with acute-on-chronic liver failure

Ammonia is thought to be central to the pathogenesis of hepatic encephalopathy (HE), but its prognostic role in acute-on-chronic liver failure (ACLF) is still unknown. We aimed to determine the association between serum ammonia level and short-term prognosis in ACLF. Furthermore, we performed an in-depth evaluation of the independent effect of serum ammonia level on the short-term prognosis of hepatitis B virus (HBV) reactivation-induced ACLF patients. We identified 174 patients as part of prospective observational studies in patients with ACLF. Plasma ammonia levels were measured on admission, and several prognostic scores were used to determine the prognostic effect of ammonia. The 28-day patient survival was determined. Receiver operating characteristic analysis was used to identify the cut-off points for ammonia values, and multivariable analysis was performed using the Cox proportional hazard regression model. Plasma ammonia was significantly higher in nonsurvivors (83.53 ± 43.78 versus 67.13 ± 41.77 µmol/L, P = 0.013), and ACLF patients with hyperammonemia had significantly higher 28-day mortality than those without hyperammonemia. Ammonia was also closely related to ACLF grade (P < 0.001) and organ failure, including liver (P = 0.048), coagulation (P < 0.001) and brain (P < 0.001). HBV reactivation serves as the main precipitating factor in the ACLF population. Subgroup analysis showed that ammonia is also a strong prognostic factor in the HBV reactivation-induced ACLF population. Ammonia level is closely correlated with failure of other organs and is an independent risk factor for mortality in ACLF and the special population defined as HBV reactivation-related ACLF. Based on the results from our study, we measured serum ammonia in the population with ACLF, which strongly indicates their prognosis. It serves as an important biomarker and a therapeutic target.

Ammonia predicts poor outcomes in patients with hepatitis B virus-related acute-on-chronic liver failure

BACKGROUND

Hepatic encephalopathy (HE) is a common feature of acute liver failure and has been reported to be associated with poor outcomes. Ammonia is thought to be central to the pathogenesis of HE, but its role in hepatitis B virus-related acute-on-chronic liver failure (HBV-ACLF) is unclear. The present study aimed to assess the prognostic role of ammonia level for patients with HBV-ACLF.

METHODS

We retrospectively recruited 127 patients diagnosed with HBV-ACLF for the present study.

RESULTS

Ammonia levels at the time of admission were higher among non-surviving participants than in survivors. Increased ammonia level was found to be associated with severe liver disease and was identified as an independent predictor for mortality in patients with HBV-ACLF.

CONCLUSIONS

Our results suggest that high ammonia level at admission is an independent factor for predicting short-term mortality in patients with HBV-ACLF. Therefore, ammonia levels may represent a therapeutic target for this condition.

Important Unresolved Questions in the Management of Hepatic Encephalopathy: An ISHEN Consensus

Management of hepatic encephalopathy (HE) remains challenging from a medical and psychosocial perspective. Members of the International Society for Hepatic Encephalopathy and Nitrogen Metabolism recognized 5 key unresolved questions in HE management focused on (i) driving, (ii) ammonia levels in clinical practice, (iii) testing strategies for covert or minimal HE, (iv) therapeutic options, and (v) nutrition and patient-reported outcomes. The consensus document addresses these topical issues with a succinct review of the literature and statements that critically evaluate the current science and practice, laying the groundwork for future investigations.

Persistent or incident hyperammonemia is associated with poor outcomes in acute decompensation and acute-on-chronic liver failure

Background and Aim

The effect of elevated ammonia on organ failures (OF), apart from hepatic encephalopathy, in patients with acute decompensation (AD) of cirrhosis and acute‐on‐chronic liver failure (ACLF) is unclear. We aimed to assess the effect of persistent or incident hyperammonemia on OF and outcomes in patients with AD and ACLF.

Methods

A total of 229 patients with ACLF and 83 with AD were included. Arterial ammonia was measured on day 1 and day 3 of admission. Persistent or incident hyperammonemia was defined as a level of ≥79.5 μmol/L on day 3. The changes in ammonia levels during the first 3 days were analyzed with respect to the complications and outcomes.

Results

At admission, the median level of arterial ammonia was higher in ACLF compared to AD patients (103 vs 86 μmol/L, P < 0.001). Persistent or incident hyperammonemia was noted in 206 (66.0%) patients and was more frequent in ACLF compared to AD patients (70.7 vs 53.0%, P = 0.013). Patients with persistent or incident hyperammonemia, compared to those without it, developed a higher proportion of new‐onset OF during hospitalization involving liver (P = 0.018), kidney (P = 0.001), brain (P = 0.005), coagulation (P = 0.036), circulation (P = 0.002), and respiratory (P = 0.003) issues and had higher 28‐day mortality (log‐rank test, P < 0.001). After adjustment for chronic liver failure consortium ACLF score, persistent or incident hyperammonemia (hazard ratio, 3.174) was independently associated with 28‐day mortality. The presence of infection was an independent predictor of persistent or incident hyperammonemia.

Conclusion

Persistent or incident hyperammonemia during first 3 days of hospitalization in patients with AD or ACLF is associated with increased risk of OF and death.

Efficacy and Safety of Sodium Benzoate in The Management of Hyperammonemia in Decompensated Chronic Liver Disease of the Childhood-A Double-blind Randomized Controlled Trial

OBJECTIVE

The objective was to evaluate the efficacy and safety of sodium benzoate in the management of hyperammonemia and hepatic encephalopathy (HE) in decompensated chronic liver disease.

METHODS

It was a prospective, interventional, double-blinded randomized controlled trial conducted from August 2017 to December 2018. Children with decompensated chronic liver disease and hyperammonemia were included in the study. Those with ammonia >400 μg/dL, already receiving sodium benzoate or with grade III ascites were excluded. Group A received sodium benzoate (400 mg/kg loading dose followed by 200 mg · kg · daymaintenance for 5 days) along with the standard medical therapy. Group B received standard medical therapy with placebo.

RESULTS

A total of 108 episodes of hyperammonemia occurred in 86 patients of whom 16 were excluded. The final analysis included 46 episodes in each group. The median decrease in ammonia from baseline to day 5 was 52 μg/dL in group A versus 42 μg/dL in group B (P = 0.321). There was a significant decrease in ammonia on days 1 and 2 in group A as compared to group B, but not on subsequent days. There was no significant difference in the resolution of HE (57.1% vs 50%; P = 1), but there was higher, albeit insignificant increase in ascites in group A (15.9% vs 4.5%).

CONCLUSIONS

Addition of sodium benzoate significantly reduced the ammonia levels on the first 2 days of therapy but the effect was not sustained till day 5. The effect of sodium benzoate would probably be more sustained, if higher dosage (400 mg · kg · day) could be used under monitoring of benzoate levels. There was no effect on resolution of HE. Sodium benzoate caused an increasing trend of adverse events with no effect on short-term survival.

Acute on chronic liver failure in non-alcoholic fatty liver and alcohol associated liver disease

Acute on chronic liver failure (ACLF) presents acutely with multiple organ failure and is precipitated by an acute event. The syndrome has high short-term mortality with a potential of returning to baseline liver function if the precipitating event is controlled and patient/s survive the acute event. With heterogeneous definition across the globe of this syndrome, there is a clinical unmet need to homogenize this definition as basis for developing pathogenesis targets, collaboration across countries and centers, and identifying new therapeutic targets. Although, the syndrome can occur in any chronic liver disease with or without cirrhosis, the increasing prevalence of nonalcoholic fatty liver disease (NAFLD) and alcohol associated liver disease (AALD) all across the world, this review will discuss specific issues regarding ACLF among patients with chronic liver disease from NAFLD and ALD.

Lactulose drives a reversible reduction and qualitative modulation of the faecal microbiota diversity in healthy dogs

Hepatic encephalopathy is a frequent and debilitating complication of liver disorders. Lactulose is an established and reasonably effective treatment, yet with incompletely understood mechanisms of action. The aims of this study were to examine how the faecal microbiota composition changed before, during and after lactulose treatment in a large animal model. Healthy, privately owned dogs (n = 18) completed a prospective cohort study. Faecal samples were collected weekly, while the subjects were either on their usual diet (week 1), or a standardised diet (weeks 2-9), with added oral lactulose in weeks 6-7. DNA extraction and 16S rRNA gene sequencing were undertaken. Faecal samples from week 7 had a significantly lower microbiota richness/diversity, based on observed operational taxonomic units, Shannon/Chao1 indexes and Pielou's Evenness. Beta diversity based on UniFrac distances was significantly different in week 7 compared to weeks 1, 5 and 9. At the phylum level, week 7 was associated with a significant increase of Firmicutes and Actinobacteria, and a decrease of Bacteroidetes and Fusobacteria, when compared to weeks 5 and 9. In summary, we have shown that lactulose induces a reversible qualitative and quantitative change of the faecal microbiota, which may explain its clinical efficacy in the management of hepatic encephalopathy.

Early changes in ammonia levels and liver function in patients with advanced hepatocellular carcinoma treated by lenvatinib therapy

We aimed to investigate the early changes in ammonia levels and liver function in patients with advanced hepatocellular carcinoma treated with lenvatinib. This retrospective study included 23 patients with advanced hepatocellular carcinoma who were able to receive lenvatinib continuously for at least 1 week. We compared their ammonia levels (NH3), total bilirubin (Bil), albumin, and prothrombin (PT) activity at before and after 1 week of lenvatinib administration, and additionally, compared the 2 groups which were divided based on the presence/absence of portosystemic collaterals (PSCs). Before administration of lenvatinib the patients with PSCs had significantly worse ammonia levels and liver function than the patients without PSCs (NH₃: P = 0.013, Bil: P = 0.004, PT: P = 0.047, respectively). Moreover, the indices were worse in all the patients after 1 week of lenvatinib than before administration (NH3: P = 0.001, Bil: P = 0.025, PT: P < 0.001, respectively). Moreover, the changes in ammonia levels were investigated for 4 weeks. The ammonia level increased, to peak at 2 weeks, but decreased after 3 weeks. None of the patients discontinued lenvatinib therapy because of an adverse event. The ammonia levels of the study patients increased from baseline at 1 week after lenvatinib administration, but therapy could be continued for 4 weeks by appropriate management.