Admission Factor V Predicts Transplant-Free Survival in Acute Liver Failure

Prognostic models in acute liver failure-historic evolution and newer updates "prognostic models in acute liver failure"

Acute liver failure (ALF) is a rare and dynamic syndrome occurring as a sequela of severe acute liver injury (ALI). Its mortality ranges from 50% to 75% based on the aetiology, patients age and severity of encephalopathy at admission. With improvement in intensive care techniques, transplant-free survival in ALF has improved over time. Timely recognition of patients who are unlikely to survive with medical intervention alone is crucial since these individuals may rapidly develop multiorgan failure and render liver transplantation futile. Various predictive models, biomarkers and AI-based models are currently used in clinical practice, each with its fallacies. The King's College Hospital criteria (KCH) were initially established in 1989 to identify patients with acute liver failure (ALF) caused by paracetamol overdose or other causes who are unlikely to improve with conventional treatment and would benefit from a liver transplant. Since then, various models have been developed and validated worldwide. Most models include age, aetiology of liver disease, encephalopathy grade, and liver injury markers like INR, lactate, factor V level, factor VIII/V ratio and serum bilirubin. But none of the currently available models are dynamic and lack accuracy in predicting transplant free survival. There is an increasing interest in developing prognostic serum biomarkers that when used alone or in combination with clinical models enhance the accuracy of predicting outcomes in ALF. Genomics, transcriptomics, proteomics, and metabolomics as well as machine learning and artificial intelligence (AI) algorithms are areas of interest for developing higher-precision predictive models. Overall, the future of prognostic models in ALF is promising, with ongoing research paving the way for more accurate, personalized, and dynamic risk assessment tools that can potentially save lives in this challenging condition. This article summarizes the history of prognostic models in ALF and future trends.

Coagulopathy in acute liver failure

Acute liver failure (ALF) is a rare but rapidly progressing syndrome, marked by severe liver dysfunction and altered mental status. While definitions of ALF vary across different guidelines, with timelines ranging from 4 to 26 weeks between jaundice onset and encephalopathy, the key defining features remain encephalopathy and coagulopathy. Elevated coagulation markers, particularly prothrombin time and international normalized ratio, have traditionally been associated with bleeding risks. However, emerging evidence suggests a rebalanced state of coagulation in ALF, similar to cirrhosis, where bleeding risks-both spontaneous and procedural-are surprisingly low. Viscoelastic hemostatic assays and thrombin generation assays further confirm this rebalanced hemostatic state. Current guidelines for correcting coagulopathy in ALF remain limited, typically reserved for active bleeding or prior to high-risk invasive procedures.

Acute liver failure: A practical update

Acute liver failure is a rare and dynamic condition, with a broad aetiology and an incompletely understood pathophysiology. Management of this life-threatening disease requires critical care and organ support and frequently early liver transplantation. Proper identification, prevention and treatment of complications such as intracranial hypertension and sepsis are critical to optimising outcomes. The identification of the cause of acute liver failure and the prompt initiation of the aetiological treatment can also improve prognosis. Survival has progressively improved in parallel to advances in medical treatment. Intracranial hypertension complicating hepatic encephalopathy is less frequent than in the past and intracranial pressure monitoring now relies on non-invasive techniques. Current prognostic models have good accuracy to identify patients who will die without liver transplantation but are not able to identify those in whom transplantation is futile. New prognostic markers to select patients for transplantation are still in the pipeline. Therapeutic plasma exchange and, in some centers, early renal replacement therapy are well established treatments for the disease. The use of other artificial liver devices in clinical practice is not supported by evidence. This review is intended to provide a clinical update on the management of acute liver failure, incorporating the most recent advances in the field.

Future directions in acute liver failure

Acute liver failure (ALF) describes a clinical syndrome of rapid hepatocyte injury leading to liver failure manifested by coagulopathy and encephalopathy in the absence of pre-existing cirrhosis. The hallmark diagnostic features are a prolonged prothrombin time (ie, an international normalized ratio of prothrombin time of ≥1.5) and any degree of mental status alteration (HE). As a rare, orphan disease, it seemed an obvious target for a multicenter network. The Acute Liver Failure Study Group (ALFSG) began in 1997 to more thoroughly study and understand the causes, natural history, and management of ALF. Over the course of 22 years, 3364 adult patients were enrolled in the study registry (2614 ALF and 857 acute liver injury-international normalized ratio 2.0 but no encephalopathy-ALI) and >150,000 biosamples collected, including serum, plasma, urine, DNA, and liver tissue. Within the Registry study sites, 4 prospective substudies were conducted and published, 2 interventional ( N -acetylcysteine and ornithine phenylacetate), 1 prognostic [ 13 C-methacetin breath test (MBT)], and 1 mechanistic (rotational thromboelastometry). To review ALFSG's accomplishments and consider next steps, a 2-day in-person conference was held at UT Southwestern Medical Center, Dallas, TX, entitled "Acute Liver Failure: Science and Practice," in May 2022. To summarize the important findings in the field, this review highlights the current state of understanding of ALF and, more importantly, asks what further studies are needed to improve our understanding of the pathogenesis, natural history, and management of this unique and dramatic condition.

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.

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

INTRODUCTION

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.

METHODS

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.

RESULTS

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.

DISCUSSION

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.

Accounting for Liver Transplant in Acute Liver Failure Research

Background and Aims

Acute liver failure (ALF) is a rare but serious disease with challenging clinical decisions, including the possibility of liver transplantation. Although there is interest in predicting who will need a transplant, that outcome is difficult to define as the decision to transplant includes many extraneous factors. The majority of research in this setting focuses on identifying factors that can provide guidance on a patient's likelihood of survival without a liver transplant. The question that arises is whether death and transplant should be combined as a poor outcome or should alternative approaches be used to account for transplant in this setting. Furthermore, does the approach to incorporating transplant information impact the accuracy of predicting survival. We aim to compare alternative analytic methods for the ALF setting to provide guidance to the clinical research community on how to handle transplant when the outcome of interest is survival without a transplant.

Methods

Five analysis approaches are compared based on model performance using existing registry data from 2100 ALF patients: logistic regression with transplant as part of the outcome, logistic regression with transplant as a covariate, inverse probability weighting, survival analysis, and multiple imputation.

Results

The various models exhibit comparable model fit with each providing advantages and challenges in implementation.

Conclusion

There are alternative modeling approaches in the ALF setting, leaving researchers with multiple valid options for how to include transplant when examining factors that may influence transplant-free survival.

Creatinine-lactate score predicts mortality in non-acetaminophen-induced acute liver failure in patients listed for liver transplantation

BACKGROUND

The aim of this study was to analyze prognostic indicators of in-hospital mortality among patients listed for urgent liver transplantation (LT) for non-acetaminophen (APAP)-induced acute liver failure (ALF).

METHODS

ALF patients listed for LT according to the King's College Criteria were retrospectively reviewed. Variables were recorded from medical records and electronic databases (HCMED and RedCap).

RESULTS

The study included 100 patients, of which 69 were subject to LT and 31 died while waiting for LT. Patients were 35.5 ± 14.73 years old, and 78% were females. The main etiologies were virus (17%), drug-induced (32%), autoimmune (15%), and indeterminate hepatitis (31%). The prioritization-to-LT time interval was 1.5 days (0-9). The non-LT patients showed higher lactate (8.71 ± 5.36 vs. 4.48 ± 3.33 mmol/L), creatinine (229 ± 207 vs. 137 ± 136 µm/L), MELD (44 ± 8 vs. 38 ± 8), and BiLE scores (15.8 ± 5.5 vs. 10.3 ± 4.1) compared to LT patients (p < 0.05). Multiple logistic regression analysis identified creatinine and lactate as independent prognostic factors, and a creatinine-lactate (CL) score was developed. ROC analysis showed that creatinine, lactate, MELD, BiLE, and CL scores had considerable specificity (71-88%), but only BiLE, lactate, and CL presented high sensitivities (70%, 80%, and 87% respectively). AUCs were 0.696 for creatinine, 0.763 for lactate, 0.697 for MELD, 0.814 for BiLE, and 0.835 for CL.

CONCLUSIONS

CL and BiLE scores predict mortality with more accuracy than MELD in patients with ALF during prioritization time. Creatinine and lactate are independent prognostic factors for mortality.

Early identification using the referral system prolonged the time to onset for hepatic encephalopathy after diagnosing severe acute liver injury

In 2004, we implemented a referral system for patients with acute liver injury (ALI) based on an established formula that estimates the risk of progression to acute live failure (ALF); however, the benefits of the system for patients with severe acute liver injury (SLI) remain unclear. We have evaluated the clinical significance of the referral system for SLI patients. Patients with ALI/SLI who were consecutively and prospectively listed on the system between 2004 and 2018 were analyzed. Of the 371 ALI/SLI/ALF patients on the system, 124 satisfied the criteria for SLI; 34 of these 124 progressed to SLI after registration. Multivariate analysis using age, sex, AST, ALT, creatinine, total bilirubin, prothrombin, presence of hepatic encephalopathy (HE), and SLI at registration revealed that HE was associated with high mortality. Among the 23 patients who developed HE, five who progressed to SLI after registration showed an increased time to HE development compared with patients who had SLI at the time of registration. However, there was no significant difference in survival time after HE development. We concluded that early identification of SLI patients using the referral system increased the time from SLI diagnosis to HE development.