Acute Liver Failure Study Group Research Articles

Ammonia and urea metabolism in acute liver failure: A multicentre cohort study.

Ammonia is metabolized into urea in the liver. In acute liver failure (ALF), ammonia has been associated with survival. However, urea variation has been poorly studied. Observational cohort including ALF patients from Curry Cabral Hospital (Lisbon, Portugal) and Clinic Hospital (Barcelona, Spain) between 10/2010 and 01/2023. The United States ALF Study Group cohort was used for external validation. Primary exposures were serum ammonia and urea on ICU admission. Primary endpoint was 30-day transplant-free survival (TFS). Secondary endpoint was explanted liver weight. Among 191 ALF patients, median (IQR) age was 46 (32; 57) years and 85 (44.5%) were males. Overall, 86 (45.0%) patients were transplanted and 75 (39.3%) died. Among all ALF patients, following adjustment for age, sex, body weight, and aetiology, higher ammonia or lower urea was independently associated with higher INR on ICU admission (p < .009). Among all ALF patients, following adjustment for sex, aetiology, and lactate, higher ammonia was independently associated with lower TFS (adjusted odds ratio (95% confidence interval [CI]) = 0.991 (0.985; 0.997); p = .004). This model predicted TFS with good discrimination (area under receiver operating curve [95% CI] = 0.78 [0.75; 0.82]) and reasonable calibration (R2 of 0.43 and Brier score of 0.20) after external validation. Among transplanted patients, following adjustment for age, sex, actual body weight, and aetiology, higher ammonia (p = .024) or lower (p < .001) urea was independently associated with lower explanted liver weight. Among ALF patients, serum ammonia and urea were associated with ALF severity. A score incorporating serum ammonia predicted TFS reasonably well.

Macrophage activation markers are associated with infection and mortality in patients with acute liver failure.

Acute liver failure is a multisystem disorder with a high mortality and frequent need for emergency liver transplantation. Following massive innate immune system activation, soluble markers of macrophage activation are released during liver damage and their association with disease severity and prognosis requires exploration. Patients ALF from the United States Acute Liver Failure Study Group (USALFSG, n = 224) and King's College Hospital (n = 40) together with healthy controls (HC, n = 50) were recruited. Serum from early (Days 1-3) and late (>Day 3) time points were analysed for MAMs by enzyme-linked immunosorbent assay correlated to markers of illness severity and 21-day spontaneous survival. Surface expression phenotyping was performed via Flow Cytometry on CD14+ monocytes. All MAMs serum concentrations were significantly higher in ALF compared to controls (p < .0001). sCD206 concentration was higher in early and late stages of the disease in patients with bacteraemia (p = .002) and infection in general (p = .006). In MELD-adjusted multivariate modelling, sCD206 and sCD163 were independently associated with mortality. CD14+ monocyte expression of CD206 (p < .001) was higher in patients with ALF compared with controls and correlated with SOFA score (p = .018). sCD206 was independently validated as a predictor of infection in an external cohort. sCD206 is increased in serum of ALF patients with infections and poor outcome and is upregulated on CD14+ monocytes. Later measurements of sCD163 and sCD206 during the evolution of ALF have potential as mechanistic predictors of mortality. sCD206 should be explored as a biomarker of sepsis and mortality in ALF.

The chemokine CXCL14 is a novel early prognostic biomarker for poor outcome in acetaminophen-induced acute liver failure.

Patients with acetaminophen-induced acute liver failure are more likely to die while on the liver transplant waiting list than those with other causes of acute liver failure. Therefore, there is an urgent need for prognostic biomarkers that can predict the need for liver transplantation early after an acetaminophen overdose. We evaluated the prognostic potential of plasma chemokine C-X-C motif ligand 14 (CXCL14) concentrations in patients with acetaminophen (APAP) overdose (n=50) and found that CXCL14 is significantly higher in nonsurviving patients compared to survivors with acute liver failure ( p < 0.001). Logistic regression and AUROC analyses revealed that CXCL14 outperformed the MELD score, better discriminating between nonsurvivors and survivors. We validated these data in a separate cohort of samples obtained from the Acute Liver Failure Study Group (n = 80), where MELD and CXCL14 had similar AUC (0.778), but CXCL14 demonstrated higher specificity (81.2 vs. 52.6) and positive predictive value (82.4 vs. 65.4) for death or need for liver transplantation. Next, combining the patient cohorts and using a machine learning training/testing scheme to mimic the clinical scenario, we found that CXCL14 outperformed MELD based on AUC (0.821 vs. 0.787); however, combining MELD and CXCL14 yielded the best AUC (0.860). We find in 2 independent cohorts of acetaminophen overdose patients that circulating CXCL14 concentration is a novel early prognostic biomarker for poor outcomes, which may aid in guiding decisions regarding patient management. Moreover, our findings reveal that CXCL14 performs best when measured soon after patient presentation to the clinic, highlighting its importance for early warning of poor prognosis.

Prognostic Markers in Pediatric Acute Liver Failure

Introduction: Acute liver failure (ALF), although rare in children, is a complex progressive pathology, with multisystem involvement and high mortality. Isolated variables or those included in prognostic scores have been studied, to optimize organ allocation. However, its validation is challenging. This study aimed to assess the accuracy of several biomarkers and scores as predictors of prognosis in pediatric ALF (PALF). Methods: An observational study with retrospective data collection, including all cases of ALF, was defined according to the criteria of the Pediatric Acute Liver Failure Study Group, admitted to a pediatric intensive care unit (PICU) for 28 years. Two groups were defined: spontaneous recovery (SR) and non-SR (NSR) – submitted to liver transplantation (LT) or death at PICU discharge. Results: Fifty-nine patients were included, with a median age of 24 months, and 54% were female. The most frequent etiologies were metabolic (25.4%) and infectious (18.6%); 32.2% were undetermined. SR occurred in 21 patients (35.6%). In NSR group (N = 38, 64.4%), 25 required LT (42.4%) and 19 died (32.2%), 6 (15.7%) of whom after LT. The accuracy to predict NSR was acceptable for lactate at admission (AUC 0.72; 95% CI: 0.57–0.86; p = 0.006), ammonia peak (AUC 0.72; 95% CI: 0.58–0.86; p = 0.006), and INR peak (AUC 0.70; 95% CI: 0.56–0.85; p = 0.01). The cut-off value for lactate at admission was 1.95 mmol/L (sensitivity 78.4% and specificity 61.9%), ammonia peak was 64 μmol/L (sensitivity 100% and specificity 38.1%), and INR peak was 4.8 (sensitivity 61.1% and specificity 76.2%). Lactate on admission was shown to be an independent predictor of NSR on logistic regression model. Two prognostic scores had acceptable discrimination for NSR, LIU (AUC 0.73; 95% CI: 0.59–0.87; p = 0.004) and PRISM (AUC 0.71; 95% CI: 0.56–0.86; p = 0.03). In our study, the PALF delta score (PALF-ds) had lower discrimination capacity (AUC 0.63; 95% CI: 0.47–0.78; p = 0.11). Conclusions: The lactate at admission, an easily obtained parameter, had a similar capacity than the more complex scores, LIU and PRISM, to predict NSR. The prognostic value in our population of the promising dynamic score, PALF-ds, was lower than expected.

The Role of Carbamoyl Phosphate Synthetase 1 as a Prognostic Biomarker in Patients With Acetaminophen-induced Acute Liver Failure

Carbamoyl phosphate synthetase 1 (CPS1) is a highly abundant mitochondrial urea cycle enzyme that is expressed primarily in hepatocytes. CPS1 is constitutively and physiologically secreted into bile but is released into the bloodstream upon acute liver injury (ALI). Given its abundance and known short half-life, we tested the hypothesis that it may serve as a prognostic serum biomarker in the setting of acute liver failure (ALF). CPS1 levels were determined using enzyme-linked immunosorbent assay and immunoblotting of sera collected by the ALF Study Group (ALFSG) from patients with ALI and ALF (103 patients with acetaminophen and 167 non-acetaminophen ALF etiologies). A total of 764 serum samples were examined. The inclusion of CPS1 was compared with the original ALFSG Prognostic Index by area under the receiver operating characteristic curve analysis. CPS1 values for acetaminophen-related patients were significantly higher than for non-acetaminophen patients (P < .0001). Acetaminophen-related patients who received a liver transplant or died within 21 days of hospitalization exhibited higher CPS1 levels than patients who spontaneously survived (P= .01). Logistic regression and area under the receiver operating characteristic analysis of CPS1 enzyme-linked immunosorbent assay values improved the accuracy of the ALFSG Prognostic Index, which performed better than the Model for End-Stage Liver Disease, in predicting 21-day transplant-free survival for acetaminophen- but not non-acetaminophen-related ALF. An increase of CPS1 but not alanine transaminase or aspartate transaminase, when comparing day 3 with day 1 levels was found in a higher percentage of acetaminophen transplanted/dead patients (P < .05). Serum CPS1 determination provides a new potential prognostic biomarker to assess patients with acetaminophen-induced ALF.

Association of FDA Mandate Limiting Acetaminophen (Paracetamol) in Prescription Combination Opioid Products and Subsequent Hospitalizations and Acute Liver Failure

In January 2011, the US Food and Drug Administration (FDA) announced a mandate to limit acetaminophen (paracetamol) to 325 mg/tablet in combination acetaminophen and opioid medications, with manufacturer compliance required by March 2014. To assess the odds of hospitalization and the proportion of acute liver failure (ALF) cases with acetaminophen and opioid toxicity prior to and after the mandate. This interrupted time-series analysis used hospitalization data from 2007-2019 involving ICD-9/ICD-10 codes consistent with both acetaminophen and opioid toxicity from the National Inpatient Sample (NIS), a large US hospitalization database, and ALF cases from 1998-2019 involving acetaminophen and opioid products from the Acute Liver Failure Study Group (ALFSG), a cohort of 32 US medical centers. For comparison, hospitalizations and ALF cases consistent with acetaminophen toxicity alone were extracted from the NIS and ALFSG. Time prior to and after the FDA mandate limiting acetaminophen to 325 mg in combination acetaminophen and opioid products. Odds of hospitalization involving acetaminophen and opioid toxicity and percentage of ALF cases from acetaminophen and opioid products prior to and after the mandate. In the NIS, among 474 047 585 hospitalizations from Q1 2007 through Q4 2019, there were 39 606 hospitalizations involving acetaminophen and opioid toxicity; 66.8% of cases were among women; median age, 42.2 (IQR, 28.4-54.1). In the ALFSG, from Q1 1998 through Q3 2019, there were a total of 2631 ALF cases, of which 465 involved acetaminophen and opioid toxicity; 85.4% women; median age, 39.0 (IQR, 32.0-47.0). The predicted incidence of hospitalizations 1 day prior to the FDA announcement was 12.2 cases/100 000 hospitalizations (95% CI, 11.0-13.4); by Q4 2019, it was 4.4/100 000 hospitalizations (95% CI, 4.1-4.7) (absolute difference, 7.8/100 000 [95% CI, 6.6-9.0]; P < .001). The odds of hospitalizations with acetaminophen and opioid toxicity increased 11%/y prior to the announcement (odds ratio [OR], 1.11 [95% CI, 1.06-1.15]) and decreased 11%/y after the announcement (OR, 0.89 [95% CI, 0.88-0.90]). The predicted percentage of ALF cases involving acetaminophen and opioid toxicity 1 day prior to the FDA announcement was 27.4% (95% CI, 23.3%-31.9%); by Q3 2019, it was 5.3% (95% CI, 3.1%-8.8%) (absolute difference, 21.8% [95% CI, 15.5%-32.4%]; P < .001). The percentage of ALF cases involving acetaminophen and opioid toxicity increased 7% per year prior to the announcement (OR, 1.07 [95% CI, 1.03-1.1]; P < .001) and decreased 16% per year after the announcement (OR, 0.84 [95% CI, 0.77-0.92]; P < .001). Sensitivity analyses confirmed these findings. The FDA mandate limiting acetaminophen dosage to 325 mg/tablet in prescription acetaminophen and opioid products was associated with a statistically significant decrease in the yearly rate of hospitalizations and proportion per year of ALF cases involving acetaminophen and opioid toxicity.

Autoimmune hepatitis presenting as acute liver failure: A 20-year retrospective review of North America.

Autoimmune hepatitis is a common cause of acute liver failure. Treatment includes steroids for acute liver injury and liver transplantation in those who fail to respond or develop acute liver failure. The aim of this study is to further characterize acute liver failure secondary to autoimmune hepatitis and identify variables that predict 21-day transplant-free survival. This study included adults hospitalized with acute liver failure enrolled in the Acute Liver Failure Study Group Registry between 1998 and 2019 from 32 centers within the US. The etiology of all cases was reviewed by the Adjudication Committee, and all cases identified as autoimmune hepatitis were included. Acute liver injury was defined as an INR ≥2.0 without encephalopathy and acute liver failure as INR ≥ 1.5 with encephalopathy. Laboratory and clinical data were reviewed. Variables significantly associated with 21-day transplant-free survival were used to develop a multivariable logistic regression model. A total of 193 cases of acute liver failure secondary to autoimmune hepatitis were identified and reviewed. There were 161 patients (83.4%) diagnosed with acute liver failure on enrollment, and 32 (16.6%) developed acute liver failure during hospitalization. At 21 days, 115 (59.6%) underwent liver transplantation, 28 (14.5%) had transplant-free survival, and 46 (23.8%) died before liver transplantation. Higher admission values of bilirubin, INR, and coma grade were associated with worse outcomes. A prognostic index incorporating bilirubin, INR, coma grade, and platelet count had a concordance statistic of 0.84. Acute liver failure secondary to autoimmune hepatitis is associated with a high short-term mortality. We developed a model specifically for autoimmune hepatitis that may be helpful in predicting 21-day transplant-free survival and early identification of patients in need of expedited liver transplant evaluation.

Acute Liver Failure: Biomarkers Evaluated by the Acute Liver Failure Study Group.

There has been a growing interest in identifying prognostic biomarkers that alone or with available prognostic models (King's College Criteria, KCC; MELD and ALFSG Prognostic Index) would improve prognosis in acute liver failure (ALF) patients being assessed for liver transplantation. The Acute Liver Failure Study Group (ALFSG) has evaluated 15 potential prognostic biomarkers: serum AFP; apoptosis-associated proteins; serum actin-free Gc-globulin; serum glycodeoxycholic acid; sRAGE/RAGE ligands; plasma osteopontin; circulating MBL, M-, L-, H-ficolin and CL-1; plasma galectin-9; serum FABP1; serum Lct2; miRNAs; factor V; thrombocytopenia, and sCD163. The ALFSG also has reported on 4 susceptibility biomarkers: keratins 8 and 18 (K8/K18) gene variants; polymorphisms of genes encoding putative APAP-metabolizing enzymes ( UGT1A1 , UGT 1A0 , UGT 2B15 , SULT1A1 , CYP2E1 , and CYP3A5 ) as well as CD44 and BHMT1 ; single nucleotide polymorphisms (SNPs) of genes associated with human behavior, rs2282018 in the arginine vasopressin ( AVP ) gene and rs11174811 in the AVP receptor 1A gene. Finally, rs2277680 of the CSCL16 gene in HBV-ALF patients. In conclusion, we have reviewed the prognostic and susceptibility biomarkers studied by the ALFSG. We suggest that a better approach to predicting the clinical outcome of an ALF patient will require a combination of biomarkers of pathogenic processes such as cell death, hepatic regeneration, and degree of inflammation that could be incorporated into prognostic models such as KCC, MELD or ALFSG PI.

Hypochloremia as a novel adverse prognostic factor in acute liver failure.

Emerging evidence has identified hypochloremia as an independent predictor for mortality in multiple conditions including cirrhosis. Acute liver failure (ALF) is frequently complicated by electrolyte abnormalities. We investigated the prognostic value of hypochloremia in a large cohort of ALF patients from North America. The Acute Liver Failure Study Group (ALFSG) registry is a longitudinal cohort study involving 2588 ALF patients enrolled prospectively from 32 North American academic centres. The primary outcome was a composite of 21-day all-cause mortality or requirement for liver transplantation (death/LT). Patients with hypochloremia (<98 mEq/L) had a significantly higher 21-day mortality rate (42.1%) compared with those with normal (27.5%) or high (>107 mEq/L) chloride (28.0%) (p< .001). There was lower transplant-free cumulative survival in the hypochloremic group than in the normo- or hyper-chloremic groups (log-rank, χ2 24.2, p< .001). Serum chloride was inversely associated with the hazard of 21-day death/LT with multivariable adjustment for known prognostic factors (adjusted hazard ratio [aHR]: 0.977; 95% CI: 0.969-0.985; p< .001). Adding chloride to the ALFSG Prognostic Index more accurately predicted risk of death/LT in 19% of patients (net reclassification improvement [NRI]=0.19, 95% CI: 0.13-0.25) but underestimated the probability of transplant-free survival in 34% of patients (NRI=-0.34, 95% CI: -0.39 to -0.28). Hypochloremia is a novel independent adverse prognostic factor in ALF. A new ALFSG-Cl Prognostic Index may improve the sensitivity to identify patients at risk for death without LT.

Whole Exome Sequencing Reveals Genetic Variants in HLA Class II Genes Associated With Transplant-free Survival of Indeterminate Acute Liver Failure.

Indeterminate acute liver failure (IND-ALF) is a rare clinical syndrome with a high mortality rate. Lacking a known etiology makes rapid evaluation and treatment difficult, with liver transplantation often considered as the only therapeutic option. Our aim was to identify genetic variants from whole exome sequencing data that might be associated with IND-ALF clinical outcomes. Bioinformatics analysis was performed on whole exome sequencing data for 22 patients with IND-ALF. A 2-tier approach was used to identify significant single-nucleotide polymorphisms (SNPs) associated with IND-ALF clinical outcomes. Tier 1 identified the SNPs with a higher relative risk in the IND-ALF population compared with those identified in control populations. Tier 2 determined the SNPs connected to transplant-free survival and associated with model for end-stage liver disease serum sodium and Acute Liver Failure Study Group prognostic scores. Thirty-one SNPs were found associated with a higher relative risk in the IND-ALF population compared with those in controls, of which 11 belong to the human leukocyte antigen (HLA) class II genes but none for the class I. Further analysis showed that 5 SNPs: rs796202376, rs139189937, and rs113473719 of HLA-DRB5; rs9272712 of HLA-DQA1; and rs747397929 of IDO1 were associated with a higher probability of IND-ALF transplant-free survival. Using 3 selected SNPs, a model for the polygenic risk score was developed to predict IND-ALF prognoses, which are comparable with those by model for end-stage liver disease serum sodium and Acute Liver Failure Study Group prognostic scores. Certain gene variants in HLA-DRB5, HLA-DQA1, and IDO1 were found associated with IND-ALF transplant-free survival. Once validated, these identified SNPs may help elucidate the mechanism of IND-ALF and assist in its diagnosis and management.

Persistent But Not Transient Acute Kidney Injury Was Associated With Lower Transplant-Free Survival in Patients With Acute Liver Failure: A Multicenter Cohort Study.

Acute liver failure (ALF) is an orphan disease often complicated by acute kidney injury (AKI). We assessed the impact of transient versus persistent AKI on survival in patients with ALF. International multicenter retrospective cohort. U.S. ALF Study Group prospective registry. Patients with greater than or equal to 18 years and ALF in the registry from 1998 to 2016 were included. Patients with less than 3 days of follow-up, without kidney function evaluation on day 3, or with cirrhosis were excluded. AKI was defined by Kidney Disease Improving Global Outcomes guidelines on day 1. Kidney recovery was defined on day 3 as transient AKI, by a return to no-AKI within 48 hours or persistent AKI if no such recovery or renal replacement therapy (RRT) was observed. Primary outcome was transplant-free survival (TFS) at 21 days. Among 1,071 patients with ALF, 339 (31.7%) were males, and median (interquartile range) age was 39 years (29-51 yr). Acetaminophen-related ALF was found in 497 patients (46.4%). On day 1, 485 of 1,071 patients (45.3%) had grade 3-4 hepatic encephalopathy (HE), 500 of 1,070 (46.7%) required invasive mechanical ventilation (IMV), 197 of 1,070 (18.4%) were on vasopressors, and 221 of 1,071 (20.6%) received RRT. On day 1, 673 of 1,071 patients (62.8%) had AKI. On day 3, 72 of 1,071 patients (6.7%) had transient AKI, 601 of 1,071 (56.1%) had persistent AKI, 71 of 1,071 (6.6%) had late onset AKI, and 327 of 1,071 (30.5%) remained without AKI. Following adjustment for confounders (age, sex, race, etiology, HE grade, use of IMV and vasopressors, international normalized ratio, and year), although persistent acute kidney injury (adjusted odds ratio [aOR] [95% CI] 0.62 [0.44-0.88]) or late onset AKI (aOR [95% CI] 0.48 [0.26-0.89]) was associated with lower TFS, transient AKI was not (aOR [95% CI] 1.89 [0.99-3.64]). In a multicenter cohort of patients with ALF, persistent but not transient AKI was independently associated with lower short-term TFS.

Proteomics Indicates Lactate Dehydrogenase Is Prognostic in Acetaminophen-Induced Acute Liver Failure Patients and Reveals Altered Signaling Pathways.

Better biomarkers to predict death early in acute liver failure (ALF) are needed. To that end, we obtained early (study day 1) and later (day 3) serum samples from transplant-free survivors (n = 28) and nonsurvivors (n = 30) of acetaminophen-induced ALF from the NIH-sponsored Acute Liver Failure Study Group and from control volunteers (n = 10). To identify proteins that increase early in serum during ALF, we selected individuals from this cohort for whom alanine aminotransferase was lower on day 1 than day 3, indicating a time point before peak injury (n = 10/group). We then performed untargeted proteomics on their day 1 samples. Out of 1682 quantifiable proteins, 361 were ≥ 4-fold elevated or decreased in ALF patients versus controls and 16 of those were further elevated or decreased ≥ 4-fold in nonsurvivors versus survivors, indicating potential to predict death. Interestingly, 1 of the biomarkers was lactate dehydrogenase (LDH), which is already measured in most clinical laboratories. To validate our proteomics results and to confirm the prognostic potential of LDH, we measured LDH activity in all day 1 and 3 samples from all 58 ALF patients. LDH was elevated in the nonsurvivors versus survivors on both days. In addition, it had prognostic value similar to the model for end-stage liver disease and outperformed the King's College Criteria, while a combination of model for end-stage liver disease and LDH together outperformed either alone. Finally, bioinformatics analysis of our proteomics data revealed alteration of numerous signaling pathways that may be important in liver regeneration. Overall, we conclude LDH can predict death in APAP-induced ALF.

Secular Trends in Severe Idiosyncratic Drug-Induced Liver Injury in North America: An Update From the Acute Liver Failure Study Group Registry.

Idiosyncratic drug-induced liver injury (DILI) is the second leading cause of acute liver failure (ALF) in the United States. Our study aims were to characterize secular trends in the implicated agents, clinical features, and outcomes of adults with DILI ALF over a 20-year period. Among 2,332 patients with ALF enrolled in the ALF Study Group registry, 277 (11.9%) were adjudicated as idiosyncratic DILI ALF (INR ≥ 1.5 and hepatic encephalopathy) through expert opinion. The 155 cases in era 1 (January 20, 1998-January 20, 2008) were compared with the 122 cases in era 2 (January 21, 2008-January 20, 2018). Among 277 cases of DILI ALF, 97 different agents, alone or in combination, were implicated: antimicrobials, n = 118 (43%); herbal/dietary supplements (HDS), n = 42 (15%); central nervous system agents/illicit substances, n = 37 (13%); oncologic/biologic agents, n = 29 (10%); and other, n = 51 (18%). Significant trends over time included (i) an increase in HDS DILI ALF (9.7% vs 22%, P < 0.01) and decrease in antimicrobial-induced DILI ALF (45.8% vs. 38.5%, P = 0.03) and (ii) improved overall transplant-free survival (23.5%-38.7%, P < 0.01) while the number of patients transplanted declined (46.4% vs 33.6%, P < 0.03). DILI ALF in North America is evolving, with HDS cases rising and other categories of suspect drugs declining. The reasons for a significant increase in transplant-free survival and reduced need for liver transplantation over time remain unclear but may be due to improvements in critical care, increased NAC utilization, and improved patient prognostication.

Coagulation Factors as Predictive Markers of Poor Outcomes in Children with Acute Liver Failure.

In children, acute liver failure (ALF) is a severe condition associated with high mortality if an emergency liver transplantation (LT) is impossible. Clinical laboratory parameters and different scores or criteria are used to predict ALF evolution in children. We aimed to assess the role of coagulation factors as predictive markers of poor outcomes in children with ALF. The prospective study included 40 children with ALF, diagnosed based on the Pediatric ALF study group criteria. Patients with emergency LT or deceased were considered with poor outcomes. For all patients, we analyzed clinical and laboratory parameters (including plasma level of factor V (FV), factor VII (FVII), and INR). We calculated the PELD (Pediatric End-stage Liver Disease) and MELD (Model for End-stage Liver Disease) scores, King's College Hospital (KCH), and Clichy criteria. We analyzed their performance in predicting a poor outcome. FV and FVII levels were significantly lower in children with poor outcomes than survivors (18.92 ± 19.95% vs. 10.72 ± 10.21%, p = 0.00139, respectively 46.51 ± 26.05% vs. 10.72 ± 10.21%, p = 0.00014). These parameters varied with ALF etiology, being the lowest in metabolic and infectious causes. The maximum value of INR (INR-max) was higher in children with poor outcomes than survivors (7.05 ± 3.20 vs. 2.96 ± 1.82, p = 0.000007), as it also was for the PELD/MELD score (30.06 ± 15.55 vs. 15.77 ± 9.64, p = 0.00092). FVII, FV, and INR-max had an excellent performance in predicting the poor outcome with an area under the ROC curve of 0.894, 0.816, and 0.861, respectively. KCH criteria had a higher sensitivity than Clichy criteria (92.86% vs. 50%) but lower specificity (53.85% vs. 95%). Our results support the role of coagulation factors (INR, FV, and FVII) as predictive markers for the fatal evolution of children with ALF and underlined the need for monitoring along with the usual liver function tests in children with ALF.

Hypophosphatemia in acute liver failure of a broad range of etiologies is associated with phosphaturia without kidney damage or phosphatonin elevation

Hypophosphatemia is a common and dangerous complication of acute liver failure (ALF) of various etiologies. While various mechanisms for ALF-associated hypophosphatemia have been proposed including high phosphate uptake into regenerating hepatocytes, acetaminophen (APAP)-associated hypophosphatemia was linked to renal phosphate wasting, and APAP-induced renal tubular injury was proposed as underlying mechanism. We studied 30 normophosphatemic and 46 hypophosphatemic (serum phosphate < 2.5 mg/dL) patients from the Acute Liver Failure Study Group registry with APAP- or non-APAP-induced ALF. Since kidney injury affects phosphate excretion, patients with elevated serum creatinine (>1.2 mg/dL) were excluded. Maximal amount of renal tubular phosphate reabsorption per filtered volume (TmP/GFR) was calculated from simultaneous serum and urine phosphate and creatinine levels to assess renal phosphate handling. Instead of enhanced renal phosphate reabsorption as would be expected during hypophosphatemia of non-renal causes, serum phosphate was positively correlated with TmP/GFR in both APAP- and non-APAP-induced ALF patients (R2=0.66 and 0.46, respectively; both P < 0.0001), indicating renal phosphate wasting. Surprisingly, there was no evidence of kidney damage based on urinary markers including neutrophil gelatinase-associated lipocalin and cystatin C even in the APAP group. Additionally, there was no evidence that the known serum phosphatonins parathyroid hormone, fibroblast growth factor 23, and α-Klotho contribute to the observed hypophosphatemia. We conclude that the observed hypophosphatemia with renal phosphate wasting in both APAP- and non-APAP-mediated ALF is likely the result of renal tubular phosphate leak from yet-to-be identified factor(s) with no evidence for proximal tubular damage or contribution of known phosphatonins.

Use of the Molecular Adsorbent Recirculating System in Acute Liver Failure: Results of a Multicenter Propensity Score-Matched Study.

The molecular adsorbent recirculating system removes water-soluble and albumin-bound toxins and may be beneficial for acute liver failure patients. We compared the rates of 21-day transplant-free survival in acute liver failure patients receiving molecular adsorbent recirculating system therapy and patients receiving standard medical therapy. Propensity score-matched retrospective cohort analysis. Tertiary North American liver transplant centers. Acute liver failure patients receiving molecular adsorbent recirculating system at three transplantation centers (n = 104; January 2009-2019) and controls from the U.S. Acute Liver Failure Study Group registry. Molecular adsorbent recirculating system treatment versus standard medical therapy (control). One-hundred four molecular adsorbent recirculating system patients were propensity score-matched (4:1) to 416 controls. Using multivariable conditional logistic regression adjusting for acute liver failure etiology (acetaminophen: n = 248; vs nonacetaminophen: n = 272), age, vasopressor support, international normalized ratio, King's College Criteria, and propensity score (main model), molecular adsorbent recirculating system was significantly associated with increased 21-day transplant-free survival (odds ratio, 1.90; 95% CI, 1.07-3.39; p = 0.030). This association remained significant in several sensitivity analyses, including adjustment for acute liver failure etiology and propensity score alone ("model 2"; molecular adsorbent recirculating system odds ratio, 1.86; 95% CI, 1.05-3.31; p = 0.033), and further adjustment of the "main model" for mechanical ventilation, and grade 3/4 hepatic encephalopathy ("model 3"; molecular adsorbent recirculating system odds ratio, 1.91; 95% CI, 1.07-3.41; p = 0.029). In acetaminophen-acute liver failure (n = 51), molecular adsorbent recirculating system was associated with significant improvements (post vs pre) in mean arterial pressure (92.0 vs 78.0 mm Hg), creatinine (77.0 vs 128.2 µmol/L), lactate (2.3 vs 4.3 mmol/L), and ammonia (98.0 vs 136.0 µmol/L; p ≤ 0.002 for all). In nonacetaminophen acute liver failure (n = 53), molecular adsorbent recirculating system was associated with significant improvements in bilirubin (205.2 vs 251.4 µmol/L), creatinine (83.1 vs 133.5 µmol/L), and ammonia (111.5 vs 140.0 µmol/L; p ≤ 0.022 for all). Treatment with molecular adsorbent recirculating system is associated with increased 21-day transplant-free survival in acute liver failure and improves biochemical variables and hemodynamics, particularly in acetaminophen-acute liver failure.

A novel microRNA-based prognostic model outperforms standard prognostic models in patients with acetaminophen-induced acute liver failure

Acetaminophen (APAP)-induced acute liver failure (ALF) remains the most common cause of ALF in the Western world. Conventional prognostic models, utilising markers of liver injury and organ failure, lack sensitivity for mortality prediction. We previously identified a microRNA signature that is associated with successful regeneration post-auxiliary liver transplant and with recovery from APAP-ALF. Herein, we aimed to use this microRNA signature to develop outcome prediction models for APAP-ALF. We undertook a nested, case-control study using serum samples from 194 patients with APAP-ALF enrolled in the US ALF Study Group registry (1998-2014) at early (day 1-2) and late (day 3-5) time-points. A microRNA qPCR panel of 22 microRNAs was utilised to assess microRNA expression at both time-points. Multiple logistic regression was used to develop models which were compared to conventional prognostic models using the DeLong method. Individual microRNAs confer limited prognostic value when utilised in isolation. However, incorporating them within microRNA-based outcome prediction models increases their clinical utility. Our early time-point model (AUC= 0.78, 95% CI 0.71-0.84) contained a microRNA signature associated with liver regeneration and our late time-point model (AUC= 0.83, 95% CI 0.76-0.89) contained a microRNA signature associated with cell-death. Both models were enhanced when combined with model for end-stage liver disease (MELD) score and vasopressor use and both outperformed the King's College criteria. The early time-point model combined with clinical parameters outperformed the ALF Study Group prognostic index and the MELD score. Our findings demonstrate that a regeneration-linked microRNA signature combined with readily available clinical parameters can outperform existing prognostic models for ALF in identifying patients with poor prognosis who may benefit from transplantation. While acute liver failure can be reversible, some patients will die without a liver transplant. We show that blood test markers that measure the potential for liver recovery may help improve identification of patients unlikely to survive acute liver failure who may benefit from a liver transplant.

Role of Hepatitis E Virus Infection in North American Patients With Severe Acute Liver Injury.

INTRODUCTION:The aim of this study was to determine the role of hepatitis E virus (HEV) infection in a large cohort of prospectively enrolled patients with severe acute liver injury (ALI).METHODS:Serum samples from 594 consecutive adults enrolled between 2008 and 2018 in the US Acute Liver Failure Study Group ALI registry were tested for anti-HEV IgM and anti-HEV IgG levels. Those with detectable anti-HEV IgM underwent further testing for HEV RNA using real-time polymerase chain reaction.RESULTS:The median age of patients was 38 years; 41% were men and 72% Caucasian. Etiologies of ALI included acetaminophen hepatotoxicity (50%), autoimmune hepatitis (8.9%), hepatitis B virus (8.9%), and idiosyncratic drug-induced liver injury (7.9%). Overall, 62 patients (10.4%) were negative for anti-HEV IgM but positive for IgG, whereas only 3 men (0.5%) were positive for both anti-HEV IgM and IgG. These 3 cases were initially diagnosed as having indeterminate, HEV, and hepatitis B virus-related ALI. One of these patients had detectable HEV RNA genotype 3, and another anti-HEV IgM+ patient had detectable HEV antigens by immunohistochemistry on liver biopsy. On multivariate modeling, older (odds ratio: 1.99) and non-Caucasian subjects (odds ratio: 2.92) were significantly more likely to have detectable anti-HEV IgG (P < 0.0001).DISCUSSION:Acute HEV infection is an infrequent cause of ALI in hospitalized North American adults. The anti-HEV IgG+ patients were significantly older and more likely to be non-Caucasian. These data are consistent with other population-based studies that indicate exposure to HEV in the general US population is declining over time and might reflect a cohort effect.

Acute Liver Failure (ALF) in Pregnancy: How Much Is Pregnancy Related?

Acute liver failure (ALF), characterized by sudden onset of coagulopathy (international normalized ratio [INR]≥1.5) and encephalopathy, may occur during pregnancy either as a pregnancy-associated etiology or an unrelated and coincidental liver injury. The U.S. Acute Liver Failure Study Group, comprised of 33 tertiary care liver centers, has enrolled consecutive patients with ALF or acute liver injury (ALI; INR≥2.0 with no encephalopathy), over two decades. Etiologies, clinical features, and outcomes of 70 of 3,155 patients (2.2%) who developed ALF or ALI during pregnancy were reviewed to determine how many were pregnancy associated (pregnancy-associated liver disease; PAALD) and how many were attributed to other etiologies. Thirty-five of the 70 were considered PAALD, of whom nearly half were attributed to hemolysis, elevated liver enzymes, and low platelets (HELLP) syndrome and half to acute fatty liver of pregnancy (AFLP), although, in some instances, the distinction was unclear. Virtually all with PAALD had been delivered before hepatology referral, mostly by cesarean section. Acetaminophen toxicity accounted for 21 (60% of the remaining cases), with the remainder resulting from a variety of other causes, but not including viral hepatitis A through E. Although recovery with delivery or supportive measures was possible in most cases, 11 of 70 (16%) required liver transplantation and 8 (11%) died. Swansea criteria to diagnose AFLP were met by all patients with PAALD and also by virtually all women with other forms of ALF. Only half of those with ALF during pregnancy appeared to have HELLP or AFLP. Morbidity and mortality for mother and fetus are strongly associated with etiology of liver failure.

S2726 No Biopsy Saves Life! Rare Incidence of Liver Transplantation for Unknown T-Cell Lymphoma-Induced Acute Liver Failure

INTRODUCTION: Acute liver failure (ALF) is a rare condition characterized by acute hepatic injury causing rapid onset of coagulopathy and encephalopathy. Without prompt treatment, ALF carries an exceptionally high morbidity and mortality, and prognosis is particularly poor when ALF is attributed to malignant infiltration. We present a case of ALF of initially unknown etiology that required expedited liver transplantation. The patient was subsequently diagnosed with hepatic T-cell lymphoma, which is a potentially transplant disqualifying condition. Post-transplant, the patient completed chemotherapy and made a full recovery. CASE DESCRIPTION/METHODS: A 21-year-old male soldier without prior medical history was evacuated from an overseas deployment for 2 weeks of headaches, fatigue, nausea, and vomiting. Scleral icterus had developed in conjunction with diminished hepatic synthetic function (INR 2.8 not responsive to Vitamin K), hyperbilirubinemia (total bilirubin 12.4 mg/dL), and elevated transaminase levels (ALT/AST 1000/705 U/L). Upon stateside evaluation, he developed asterixis and progressive encephalopathy. The history obtained from the patient was reliably negative for toxic ingestions or suspect environmental exposures. The workup for vascular causes, viral and autoimmune hepatitis, Wilson disease, hemochromatosis, and alpha-1-antitrypsin deficiency was negative. An empiric treatment with n-acetylcysteine was ineffective. Per the ALF Study Group estimation, the patient had a 9% 21-day transplant free survival, and was promptly transferred to a transplant center. A liver biopsy was deferred given coagulopathy and rapid decompensation that required vasopressors and intracranial pressure reduction as a bridge to transplant. His explant demonstrated T-cell rich lymphoma with no hyper-metabolic lesions on PET scan. The patient fully recovered from surgery, completed chemotherapy, and remains in clinical remission on his immunosuppressive regimen. DISCUSSION: Less than 40 cases of ALF from hepatic lymphoma have been reported in the literature, with a majority diagnosed post-mortem. Prognosis is generally poor, and rapid clinical deterioration prompts difficult and swift decisions often based on an incomplete data set. As described with this young patient with ALF of initially unknown etiology, proceeding with liver transplant was the only life-saving option. This case demonstrates that a consideration must be made to transplant potentially disqualifying conditions that have effective established therapies.Figure 1.: Diagnostic CD3 stain for T-cell rich lymphoma.Figure 2.: Diagnostic CD20 stain for T-cell rich lymphoma.