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

The Story of Ammonia in Liver Disease: An Unraveling Continuum

Hyperammonemia and liver disease are closely linked. Most of the ammonia in our body is produced by transamination and deamination activities involving amino acid, purine, pyrimidines, and biogenic amines, and from the intestine by bacterial splitting of urea. The only way of excretion from the body is by hepatic conversion of ammonia to urea. Hyperammonemia is associated with widespread toxicities such as cerebral edema, hepatic encephalopathy, immune dysfunction, promoting fibrosis, and carcinogenesis. Over the past two decades, it has been increasingly utilized for prognostication of cirrhosis, acute liver failure as well as acute on chronic liver failure. The laboratory assessment of hyperammonemia has certain limitations, despite which its value in the assessment of various forms of liver disease cannot be negated. It may soon become an important tool to make therapeutic decisions about the use of prophylactic and definitive treatment in various forms of liver disease.

Ammonia is associated with liver-related complications and predicts mortality in acute-on-chronic liver failure patients

The relationship between ammonia and liver-related complications (LRCs) in acute-on-chronic liver failure (ACLF) patients is not clearly established. This study aimed to evaluate the association between ammonia levels and LRCs in patients with ACLF. The study also evaluated the ability of ammonia in predicting mortality and progression of LRCs. The study prospectively recruited ACLF patients based on the APASL definition from the ACLF Research Consortium (AARC) from 2009 to 2019. LRCs were a composite endpoint of bacterial infection, overt hepatic encephalopathy (HE), and ascites. A total of 3871 cases were screened. Of these, 701 ACLF patients were enrolled. Patients with LRCs had significantly higher ammonia levels than those without. Ammonia was significantly higher in patients with overt HE and ascites, but not in those with bacterial infection. Multivariate analysis found that ammonia was associated with LRCs. Additionally, baseline arterial ammonia was an independent predictor of 30-day mortality, but it was not associated with the development of new LRCs within 30 days. In summary, baseline arterial ammonia levels are associated with 30-day mortality and LRCs, mainly overt HE and ascites in ACLF patients.

Serum ammonia variation predicts mortality in patients with hepatitis B virus-related acute-on-chronic liver failure

Background

Hyperammonemia is critical to the development of hepatic encephalopathy (HE) and is associated with mortality in end-stage liver disease. This study investigated the clinical value of ammonia variation in hepatitis B virus-related acute-on-chronic liver failure (HBV-ACLF) patients.

Methods

A total of 276 patients with HBV-ACLF were retrospectively recruited. Patients' ammonia levels were serially documented. Baseline ammonia, Peak ammonia (highest level), and Trough ammonia (lowest level) were particularly corrected to the upper limit of normal (AMM-ULN). The primary endpoint was 28-day mortality.

Results

The 28-day, 3-month, and 12-month mortality rates were 19.2, 25.7, and 28.2%, respectively. A total of 51 (18.4%) patients had overt HE (grade 2/3/4). Peak AMM-ULN was significantly higher in patients with overt HE and non-survivors compared with their counterparts (P < 0.001). Following adjustment for significant confounders, high Peak AMM-ULN was an independent predictor of overt HE (hazard ratio, 1.031, P < 0.001) and 28-day mortality (hazard ratio, 1.026, P < 0.001). The cut-off of Peak AMM-ULN was 1.8, determined by using the X-tile. Patients with Peak AMM-ULN appearing on days 1-3 after admission had a higher proportion of overt HE and mortality compared to other groups. Patients with decreased ammonia levels within 7 days had better clinical outcomes than those with increased ammonia.

Conclusion

Serum Peak ammonia was independently associated with overt HE and mortality in HBV-ACLF patients. Serial serum ammonia may have prognostic value.

Intravenous BCAA Infusion Does Not Lead to a Sustained Recovery From Overt HE in ACLF - An Open Label Randomized Clinical Trial

Background

Hepatic encephalopathy (HE) in acute-on-chronic liver failure (ACLF) is associated with significant morbidity and mortality. We conducted a prospective, randomized controlled clinical trial to study the efficacy of intravenous branched chain amino acids (IV-BCAA) with lactulose versus lactulose alone for improvement in HE at 24 h, day 3, and day 7. The primary outcome was an improvement in encephalopathy by ≥ 1 grade at 72 h.

Patients and methods

European association for study of liver (EASL) defined ACLF patients with overt HE were assessed and randomized into the experimental arm (IV-BCAA - 500 mL/day for 3 days + Lactulose; n = 39) and the comparator arm (Lactulose alone; n = 37). Six patients developed COVID-19 after randomization and were excluded (4-experimental arm and 2-comparator arm).

Results

Of 222 screened patients, 70 (35 in each arm) were included in the analysis. Baseline characteristics, including HE grade (2.9 ± 0.7 vs 2.8 ± 0.7; P = 0.86) and (chronic liver failure) CLIF-C ACLF score (54.2 ± 5.6 vs 54.8 ± 5.7; P = 0.65), were similar. Overall survival was 40% at 28 days (48.5% vs 31.4%; P = 0.14). Improvement in hepatic encephalopathy scoring algorithm (HESA) by ≥ 1 grade at 24 h occurred in 14 patients (40%) in the BCAA arm and 6 patients (17.1%) in the control group (P = 0.03) which translated to a shorter intensive care unit (ICU) stay. The median change in HESA at 24 h was greater in the BCAA arm than the control arm (P = 0.006), which was not sustained at days 3 or 7. Ammonia levels did not correlate with the grade of HE (Spearman's correlation coefficient (ρ) = - 0.0843; P = 0.29).

Conclusion

Intravenous BCAA does not lead to a sustained improvement in HE grade in ACLF.

Trial registration no

NCT04238416 (clinicaltrials.gov).

Portosystemic shunt placement reveals blood signatures for the development of hepatic encephalopathy through mass spectrometry

Elective transjugular intrahepatic portosystemic shunt (TIPS) placement can worsen cognitive dysfunction in hepatic encephalopathy (HE) patients due to toxins, including possible microbial metabolites, entering the systemic circulation. We conducted untargeted metabolomics on a prospective cohort of 22 patients with cirrhosis undergoing elective TIPS placement and followed them up to one year post TIPS for HE development. Here we suggest that pre-existing intrahepatic shunting predicts HE severity post-TIPS. Bile acid levels decrease in the peripheral vein post-TIPS, and the abundances of three specific conjugated di- and tri-hydroxylated bile acids are inversely correlated with HE grade. Bilirubins and glycerophosphocholines undergo chemical modifications pre- to post-TIPS and based on HE grade. Our results suggest that TIPS-induced metabolome changes can impact HE development, and that pre-existing intrahepatic shunting could be used to predict HE severity post-TIPS.

Pre- and Post-Portosystemic Shunt Placement Metabolomics Reveal Molecular Signatures for the Development of Hepatic Encephalopathy

Hepatic encephalopathy (HE) is a common complication of advanced liver disease causing brain dysfunction. This is likely due to the accumulation of unfiltered toxins within the bloodstream. A known risk factor for developing or worsening HE is the placement of a transjugular intrahepatic portosystemic shunt (TIPS), which connects the pre-hepatic and post-hepatic circulation allowing some blood to bypass the dysfunctional liver and decreases portal hypertension. To better understand the pathophysiology of post-TIPS HE, we conducted a multi-center prospective cohort study employing metabolomic analyses on hepatic vein and peripheral vein blood samples from participants with cirrhosis undergoing elective TIPS placement, measuring chemical modifications and changes in concentrations of metabolites resulting from TIPS placement. In doing so, we identified numerous alterations in metabolites, including bile acids, glycerophosphocholines, and bilirubins possibly implicated in the development and severity of HE.

Heretical thoughts into hepatic encephalopathy

Clinical progress in the development of new diagnostic modalities and therapeutic strategies for the management of patients with hepatic encephalopathy has lagged behind the vast knowledge that has been generated from basic studies. In this article, we critically assess matters that should be revisited, such as definition, classification, diagnosis and grading of hepatic encephalopathy, which are difficult to apply reproducibly using the current criteria. Many lines of investigation have confirmed that hepatic encephalopathy is irreversible in many patients and suggest the need for further studies focussing on mechanisms of neuronal injury and death, to guide future drug development for these patients. The clinical evidence behind using lactulose for all severities of hepatic encephalopathy, which is currently considered the standard of care, is poor and placebo-controlled trials for hepatic encephalopathy should be considered ethically sound. This expert opinion identifies current challenges in hepatic encephalopathy and highlights areas which require further debate and investigation in order to help advance the field both scientifically and clinically.

The Outcome in Cirrhosis after Hospital Discharge is Not Worsened with COVID-19 Infection: A Propensity Score-matched Analysis

BACKGROUND

Patients with cirrhosis and coronavirus disease-2019 (COVID-19) have high in-hospital mortality. The information on the outcome of cirrhosis patients in the posthospitalization period is limited.

AIMS

We aimed to study the outcome of cirrhosis patients with COVID-19 after hospital discharge.

METHODS

The records of the cirrhosis patients discharged after COVID-19 were reviewed. Their data were compared with a similar number of cirrhosis patients without COVID-19 after propensity score matching for age, sex, etiology of cirrhosis, and model for end-stage liver disease (MELD) score.

RESULTS

Cirrhosis patients with (n = 92) or without (n = 92) COVID-19 were included in 1:1 ratio. The mortality among COVID-19 (22; 23.9%) and non-COVID-19 (19; 20.7%) were comparable (HR 1.224; 95% CI 0.663-2.263, P = 0.520), over a similar duration of follow-up [186 (86-271) vs. 183 (103-274)]. Among COVID-19 patients, 45; 48.9% developed a new acute decompensation-increased ascites (40; 43.5%), hepatic encephalopathy (20; 21.7%), or variceal bleeding (8; 8.7%) whereas 25 (27.2%) patients needed rehospitalization. A proportion of participants continued to have either fatigue/weakness (24/80; 30.0%), sleep disturbances (11/80; 13.7%), or joint pains (16/80; 20.0%). The most common causes of death in patients of both groups were end-stage liver disease: 16 (72.7%) vs. 9 (47.4%), followed by multiorgan dysfunction: 4 (18.2%) vs. 6 (31.6%), GI bleeding: 2 (9.1%) vs. 4 (21.0%), P = 0.484. A lower albumin level, higher international normalized ratio, bilirubin, Child-Turcotte-Pugh, and MELD scores at discharge predicted mortality in the COVID-19 group.

CONCLUSION

Short-term outcomes of patients with cirrhosis who survive the initial insult of COVID-19 are not different from patients without COVID-19, and survival is determined by the severity of liver disease at discharge.

Sarcopenia and frailty in decompensated cirrhosis

In patients with decompensated cirrhosis, sarcopenia and frailty are prevalent. Although several definitions exist for these terms, in the field of hepatology, sarcopenia has commonly been defined as loss of muscle mass, and frailty has been broadly defined as the phenotypic manifestation of the loss of muscle function. Prompt recognition and accurate assessment of these conditions are critical as they are both strongly associated with morbidity, mortality, poor quality of life and worse post-liver transplant outcomes in patients with cirrhosis. In this review, we describe the complex pathophysiology that underlies the clinical phenotypes of sarcopenia and frailty, their association with decompensation, and provide an overview of tools to assess these conditions in patients with cirrhosis. When available, we highlight data focusing on patients with acutely decompensated cirrhosis, such as inpatients, as this is an area of unmet clinical need. Finally, we discuss management strategies to reverse and/or prevent the development of sarcopenia and frailty, which include adequate nutritional intake of calories and protein, as well as regular exercise of at least moderate intensity, with a mix of aerobic and resistance training. Key knowledge gaps in our understanding of sarcopenia and frailty in decompensated cirrhosis remain, including best methods to measure muscle mass and function in the inpatient setting, racial/ethnic variation in the development and presentation of sarcopenia and frailty, and optimal clinical metrics to assess response to therapeutic interventions that translate into a reduction in adverse outcomes associated with these conditions.