Acute-on-chronic liver failure: the liver and portal haemodynamics:

Mechanisms and treatment approaches for ACLF

Acute-on-chronic liver failure (ACLF) is a life-threatening syndrome characterized by decompensation of cirrhosis, severe systemic inflammation and organ failures. ACLF is frequently triggered by intra- and/or extrahepatic insults, such as bacterial infections, alcohol-related hepatitis or flares of hepatic viruses. The imbalance between systemic inflammation and immune tolerance causes organ failures through the following mechanisms: (i) direct damage of immune cells/mediators; (ii) worsening of circulatory dysfunction resulting in organ hypoperfusion and (iii) metabolic alterations with prioritization of energetic substrates for inflammation and peripheral organ 'energetic crisis'. Currently, the management of ACLF includes the support of organ failures, the identification and treatment of precipitating factors and expedited assessment for liver transplantation (LT). Early LT should be considered in patients with ACLF grade 3, who are unlikely to recover with the available treatments and have a mortality rate > 70% at 28 days. However, the selection of transplant candidates and their prioritization on the LT waiting list need standardization. Future challenges in the ACLF field include a better understanding of pathophysiological mechanisms leading to inflammation and organ failures, the development of specific treatments for the disease and personalized treatment approaches. Herein, we reviewed the current knowledge and future perspectives on mechanisms and treatment of ACLF.

Cardiac dysfunction in patients with cirrhosis and acute decompensation

The prevalence of cirrhotic cardiomyopathy (CCM) has been reported as high as 60%-70% in patients with liver cirrhosis and is associated with various negative outcomes. There has been a growing understanding of CCM over recent years. Indeed, the development of imaging techniques has enabled new diagnostic criteria to be proposed by the Cirrhotic Cardiomyopathy Consortium. However, important unanswered questions remain over pathophysiological mechanisms, optimal diagnostic modalities and potential treatment options. While there has been an increasing volume of literature evaluating CCM, there is a lack of clarity on its implications in acute decompensation, acute-on-chronic liver failure and following interventions such as transjugular intrahepatic portosystemic shunt insertion and liver transplantation. This review aims to summarise the literature in these challenging domains and suggest where future research should focus. We conclude that systemic inflammation and structural myocardial changes are likely to be crucial in the pathophysiology of the disease, but the relative contribution of different components remains elusive. Furthermore, future studies need to use standardised diagnostic criteria for CCM as well as incorporate newer imaging techniques assessing both myocardial structure and function. Finally, while specific treatments are currently lacking, therapeutics targeting systemic inflammation, microbial dysbiosis and bacterial translocation are promising targets and warrant further research.

Midodrine versus Albumin to Prevent Paracentesis Induced Circulatory Dysfunction in Acute on Chronic Liver Failure Patients in the Outpatient Clinic-a Randomized Controlled Trial

Background

Paracentesis-induced circulatory disturbance (PICD) occurs in 12-20% of patients receiving human albumin for large-volume paracentesis, and can occur at lower than five liter paracentesis in acute-on-chronic liver failure (ACLF). Albumin infusions are associated with higher costs and more prolonged daycare admissions. The aim of the study was to determine if oral midodrine-hydrochloride can prevent PICD in these patients by increasing the mean arterial pressure (MAP).

Methods

This open-labeled randomized controlled trial included ACLF patients undergoing paracentesis between 3 and 5 L, who were randomized to receive either 20% human albumin or midodrine hydrochloride 7.5 mg thrice daily for three days, 2 h before paracentesis. MAP was recorded daily. The primary outcome was the plasma renin activity (PRA) on day six, and a 50% increase from baseline was considered PICD.

Results

183 consecutive patients of ACLF were screened, and 50 patients were randomized to either arms. Alcohol was the most common underlying cause of cirrhosis. On day 6, PRA was non-significantly (P = 0.056) higher in the midodrine group. The absolute change of PRA between the two groups was not significant (P = 0.093). Four (16%) patients in the albumin group and five (20%) in the midodrine group developed PICD. MAP increase was not different between the albumin and midodrine arms (P = 0.851). Midodrine was found to be more cost-effective.

Conclusions

Three days of oral midodrine is as effective as a human-albumin infusion in preventing PICD in ACLF patients undergoing paracentesis lesser than that done in large volume paracentesis.

Acute-on-chronic liver failure is independently associated with higher mortality for cirrhotic patients with acute esophageal variceal hemorrhage: Retrospective cohort study

BACKGROUND

Acute esophageal variceal hemorrhage (AEVH) is a common complication of cirrhosis and might precipitate multi-organ failure, causing acute-on-chronic liver failure (ACLF).

AIM

To analyze if the presence and grading of ACLF as defined by European Society for the Study of the Liver-Chronic Liver Failure (EASL-CLIF) is able to predict mortality in cirrhotic patients presenting AEVH.

METHODS

Retrospective cohort study executed in Hospital Geral de Caxias do Sul. Data from medical records from 2010 to 2016 were obtained by searching the hospital electronic database for patients who received terlipressin. Medical records were reviewed in order to determine the diagnosis of cirrhosis and AEVH, including 97 patients. Kaplan-Meier survival analysis was used for univariate analysis and a stepwise approach to the Cox regression for multivariate analysis.

RESULTS

All- cause mortality for AEVH patients was 36%, 40.2% and 49.4% for 30-, 90- and 365-day, respectively. The prevalence of ACLF was 41.3%. Of these, 35% grade 1, 50% grade 2 and 15% grade 3. In multivariate analysis, the non-use of non-selective beta-blockers, presence and higher grading of ACLF and higher Model for End-Stage Liver Disease scores were independently associated with higher mortality for 30-day with the addition of higher Child-Pugh scores for 90-day period.

CONCLUSION

Presence and grading of ACLF according to the EASL-CLIF criteria was independently associated with higher 30- and 90-day mortality in cirrhotic patients admitted due to AEVH.

Pathophysiology and management of liver cirrhosis: from portal hypertension to acute-on-chronic liver failure

Cirrhosis transcends various progressive stages from compensation to decompensation driven by the severity of portal hypertension. The downstream effect of increasing portal hypertension severity leads to various pathophysiological pathways, which result in the cardinal complications of cirrhosis, including ascites, variceal hemorrhage, and hepatic encephalopathy. Additionally, the severity of portal hypertension is the central driver for further advanced complications of hyperdynamic circulation, hepatorenal syndrome, and cirrhotic cardiomyopathy. The management of these individual complications has specific nuances which have undergone significant developments. In contrast to the classical natural history of cirrhosis and its complications which follows an insidious trajectory, acute-on-chronic failure (ACLF) leads to a rapidly downhill course with high short-term mortality unless intervened at the early stages. The management of ACLF involves specific interventions, which have quickly evolved in recent years. In this review, we focus on complications of portal hypertension and delve into an approach toward ACLF.

Effect of time to pre-emptive transjugular intrahepatic portosystemic shunt on patient outcome, a UK multicentre cohort study

BACKGROUND

Pre-emptive transjugular intrahepatic portosystemic shunt (pTIPSS) should be considered within 72 hours following acute oesophageal variceal bleeding. However, recent studies highlight the difficulty in providing pTIPSS within this narrow timeframe. Delaying pTIPSS beyond 72 hours has not been studied.

AIM

To determine if the time taken to perform pTIPSS alters patient outcome.

METHOD

Patients referred to 4 UK tertiary centres for pTIPSS between 01 January 2010 and 31 December 2018 were included. Time from endoscopy to pTIPSS was recorded and pre-defined clinically relevant outcomes were observed relative to two groups: early pTIPSS (<72 h) and late pTIPSS (72 h-28 days). The primary outcome was transplant-free survival at 1-year. Follow-up was until 31 December 2020.

RESULTS

A total of 83 patients received early pTIPSS and 88 received late pTIPSS. Baseline characteristics were similar with no requirement for propensity score-matched analysis. There was no difference between early and late pTIPSS groups for patient outcomes; 1-year transplant-free survival rate (69.9% vs 71.6%, p = 0.73, HR 0.91, 95% CI 0.52-1.58), long-term survival (p = 0.52, HR 1.132, 95% CI 0.77-1.65), variceal rebleeding (4.82% vs 11.36%, p = 0.09, HR 0.411, 95% CI 0.14-1.17), hepatic encephalopathy (43.93% vs 34.61%, p = 0.26) and new or worsening ascites (16.6% vs 13.46%, p = 0.79). Death due to liver failure was significantly more prevalent in those undergoing early pTIPSS compared to late pTIPSS (44% vs 16%, p = 0.046, HR 2.79, 95%CI 1.02-8.32).

CONCLUSION

Placement of pTIPSS within 72 hours offered similar short- and long-term survival benefits compared to pTIPSS placed between 72 hours and 28 days. Early pTIPSS may be associated with an increased risk of liver failure-related mortality. Further large, randomised studies are required to evaluate these findings.

Evidence-based protocol for diagnosis and treatment of hepatorenal syndrome is independently associated with lower mortality

BACKGROUND

Hepatorenal syndrome (HRS) is the deadliest complication of cirrhosis. The purpose of this study is to analyze if the use of a protocol for HRS is associated with higher survival in these patients.

METHODS

An evidence-based protocol for the diagnosis and treatment of HRS was instituted in 2013. Data from medical records from 2010 to 2016 were obtained by searching the hospital database for patients who received terlipressin, in the three years before and after the institution of the protocol. Data were reviewed to confirm the diagnosis of HRS and multiple variables were collected. Liver-specific scores were calculated and a stepwise Cox regression approach was used for univariate and multivariate analysis.

RESULTS

The study included 46 patients, 20 from the pre-protocol period and 26 from the post-protocol period. Respectively, mortality at 30 days, 90 days and 365 days was 75%, 75% and 90% for the pre-protocol period, and 61%, 69% and 80% for the post-protocol period. In the multivariate analysis, an aspartate aminotransferase (AST) of <40U/L, the pre-protocol period and higher Child-Turcotte-Pugh scores were associated with higher 30-day and 90-day mortality. The total mean dose of terlipressin and human albumin used per patient was reduced from 27mg to 22mg and from 236g to 144g, respectively, after the institution of the protocol. This was not associated with higher mortality.

CONCLUSION

The use of an evidence-based protocol for the treatment of HRS translated into a higher survival. The authors suggest that the use of evidence-based protocols for the diagnosis and treatment of HRS could reduce cost and mortality in tertiary hospitals.

Acute-on-Chronic Liver Failure: Pathophysiological Mechanisms and Management

Acute-on-chronic liver failure (ACLF) is a multifaceted condition with poor treatment options and high short-term mortality. ACLF can develop in patients with or without liver cirrhosis, where patients with decompensated cirrhosis display a higher risk of short-term mortality. Pathophysiological mechanisms include systemic inflammation due to bacterial and fungal infections and acute hepatic insult with drug, alcohol, and viral hepatitis. Cryptogenic factors also contribute to the development of ACLF. The clinical outcome of patients with ACLF gets further complicated by the occurrence of variceal hemorrhage, hepatorenal syndrome, hepatic encephalopathy, and systemic immune dysfunction. Regardless of the better understanding of pathophysiological mechanisms, no specific and definitive treatment is available except for liver transplantation. The recent approach of regenerative medicine using mesenchymal stem cells (MSCs) could be advantageous for the treatment of ACLF as these cells can downregulate inflammatory response by inducing antiinflammatory events and prevent hepatic damage and fibrosis by inhibiting hepatic stellate cell activation and collagen synthesis. Moreover, MSCs are involved in tissue repair by the process of liver regeneration. Considering the broad therapeutic potential of MSCs, it can serve as an alternative treatment to liver transplant in the near future, if promising results are achieved.

The Use of Rifaximin in Patients With Cirrhosis

Rifaximin is an oral nonsystemic antibiotic with minimal gastrointestinal absorption and broad-spectrum antibacterial activity covering both gram-positive and gram-negative organisms. Rifaximin is currently used worldwide in patients with cirrhosis for preventing recurrent HE because its efficacy and safety have been proven by large randomized clinical trials. In the last decade, experimental and clinical evidence suggest that rifaximin could have other beneficial effects on the course of cirrhosis by modulating the gut microbiome and affecting the gut-liver axis, which in turn can interfere with major events of the pathophysiological cascade underlying decompensated cirrhosis, such as systemic inflammatory syndrome, portal hypertension, and bacterial infections. However, the use of rifaximin for prevention or treatment of other complications, including spontaneous bacterial peritonitis or other bacterial infections, is not accepted because evidence by clinical trials is still very weak. The present review deals in the first part with the potential impact of rifaximin on pathogenic mechanisms in liver diseases, whereas in the second part, its clinical effects are critically discussed. It clearly emerges that, because of its potential activity on multiple pathogenic events, the efficacy of rifaximin in the prevention or management of complications other than HE deserves to be investigated extensively. The results of double-blinded, adequately powered randomized clinical trials assessing the effect of rifaximin, alone or in combination with other drugs, on hard clinical endpoints, such as decompensation of cirrhosis, acute-on-chronic liver failure, and mortality, are therefore eagerly awaited.

ACUTE-ON-CHRONIC LIVER FAILURE IS INDEPENDENTLY ASSOCIATED WITH LOWER SURVIVAL IN PATIENTS WITH SPONTANEOUS BACTERIAL PERITONITIS

BACKGROUND

Spontaneous bacterial peritonitis (SBP) is a decompensation of cirrhosis with an in-hospital mortality ranging from 20% to 40%.

OBJECTIVE

The purpose of this study is to analyze if EASL-CLIF definition of acute-on-chronic liver failure (ACLF) is able to predict mortality in cirrhotic patients with SBP.

METHODS

Historical cohort study conducted in a public tertiary care teaching hospital. Data from medical records from January 2009 to July 2016 were obtained by searching the hospital electronic database for samples of ascites collected in the period. Electronic and physical medical records were analyzed and patients were included if they were over 18-years old, with cirrhosis and an ascites fluid compatible with SBP: 69 patients were included. Liver-specific scores were calculated and Kaplan-Meier survival analysis was used for univariate analysis and a stepwise approach to the Cox regression for multivariate analysis.

RESULTS

All cause mortality was 44%, 56.5% and 74% for 28-, 90- and 365-day, respectively. The prevalence of ACLF was 58%. Of these, 65% grade 1, 17.5% grade 2 and 17.5% grade 3. In multivariate analysis, the use of proton-pump inhi-bitors, alanine transaminase lower than 40 U/L, hemoglobin higher than 9 g/dL, absence of ACLF and lower CLIF-SOFA and MELD scores were independently associated with higher survival for both 28- and 90-day interval.

CONCLUSION

The presence of ACLF and higher CLIF-SOFA scores were independently associated with higher 28- and 90-day mortality in cirrhotic patients admitted due to SBP.

Randomised clinical trial: standard of care versus early-transjugular intrahepatic porto-systemic shunt (TIPSS) in patients with cirrhosis and oesophageal variceal bleeding

BACKGROUND

Early-transjugular intrahepatic porto-systemic shunt (TIPSS) has been recommended in international guidelines for high-risk patients with oesophageal variceal bleeding.

AIM

To validate the results of a previous randomised control trial which supports use of early-TIPSS.

METHODS

In a two-centre open-label parallel-group randomised control trial, patients with cirrhosis and acute variceal bleeding were recruited following haemostasis with vaso-active drugs and endoscopic band ligation. Participants were randomised to standard of care or early-TIPSS. The primary outcome was 1-year survival, secondary outcomes included early and late rebleeding, and complications of portal hypertension.

RESULTS

Fifty-eight patients (58 ± 11.12 years; 32.7% female) were randomised. After one year, seven patients died in the standard of care group and six in the early-TIPSS group, a 1-year survival of 75.9% vs 79.3% respectively (P = 0.79). Variceal rebleeding occurred in eight patients in the standard of care group compared with three patients in the early-TIPSS group (P = 0.09). Not all participants randomised to early-TIPSS received the intervention in time. For those receiving TIPSS per-protocol, variceal rebleeding rates were reduced (0% vs 27.6%, P = 0.04) but this had no effect on survival (76.9% vs 75.9%, P = 0.91). Serious adverse events were similar in both treatment groups, except that rates of hepatic encephalopathy were higher in patients receiving TIPSS (46.1% vs 20.7%, P < 0.05).

CONCLUSIONS

Early-TIPSS reduced variceal rebleeding, increased encephalopathy but had no effect on survival in high-risk patients with oesophageal variceal bleeding. Early-TIPSS may not be feasible in many centres however, larger studies are needed. ClinicalTrials.gov reference: NCT02377141.

Treatment with carvedilol improves survival of patients with acute-on-chronic liver failure: a randomized controlled trial

BACKGROUND AND AIMS

In addition to the portal pressure reducing effect, non-selective beta blockers (NSBBs) have possible immunomodulatory and effect in reducing bacterial translocation. Recently, it has been shown that patients who are already on NSBBs should be continued on them (if feasible), if acute-on-chronic liver failure (ACLF) develops. It, however, remains unknown if patients with ACLF and no or small esophageal varices at presentation will benefit from the use of NSBBs. We studied the efficacy and safety of carvedilol in patients with ACLF in reducing mortality, variceal bleeding and non-bleeding complications.

METHODS

136 patients with ACLF (with no or small esophageal varices and HVPG ≥ 12 mmHg) were randomized to either carvedilol (n = 66) or placebo arms (n = 70).

RESULTS

Within 28 days, 7 (10.6%) of 66 patients in the carvedilol group and 17 (24.3%) of 70 in the placebo group died (p= 0.044). Fewer patients in the carvedilol compared to placebo group developed acute kidney injury (AKI) (13.6% vs 35.7%, p = 0.003 and spontaneous bacterial peritonitis (SBP) (6.1% vs 21.4%, p= 0.013). Significantly, more patients in the placebo group had increase in APASL ACLF Research Consortium-ACLF grade (22.9% vs 6.1%, p= 0.007). There was no significant difference in the 90-day transplant-free survival rate and development of AKI, SBP, non-SBP infections (including pneumonia) and variceal bleed within 90 days, between the two groups.

CONCLUSIONS

In ACLF patients with either no or small esophageal varices and HVPG ≥ 12 mmHg, carvedilol leads to improved survival and fewer AKI and SBP events up to 28 days. CLINICALTRIALS.

GOV IDENTIFIER NUMBER

NCT02583698.

Post-Transcriptional Regulation of Hepatic DDAH1 with TNF Blockade Leads to Improved eNOS Function and Reduced Portal Pressure In Cirrhotic Rats

Portal hypertension (PH) is a major cause of morbidity and mortality in chronic liver disease. Infection and inflammation play a role in potentiating PH and pro-inflammatory cytokines, including TNF, are associated with severity of PH. In this study, cirrhotic bile duct ligated (BDL) rats with PH were treated with Infliximab (IFX, a monoclonal antibody against TNF) and its impact on modulation of vascular tone was assessed. BDL rats had increased TNF and NFkB compared to sham operated rats, and their reduction by IFX was associated with a reduction in portal pressure. IFX treatment also reduced hepatic oxidative stress, and biochemical markers of hepatic inflammation and injury. IFX treatment was associated with an improvement in eNOS activity and increased l-arginine/ADMA ratio and DDAH1 expression. In vitro analysis of HepG2 hepatocytes showed that DDAH1 protein expression is reduced by oxidative stress, and this is in part mediated by post-transcriptional regulation by the 3′UTR. This study supports a role for the DDAH1/ADMA axis on the effect of inflammation and oxidative stress in PH and provides insight for new therapies.

Caval Subtraction 2D Phase-Contrast MRI to Measure Total Liver and Hepatic Arterial Blood Flow: Proof-of-Principle, Correlation With Portal Hypertension Severity and Validation in Patients With Chronic Liver Disease

OBJECTIVES

Caval subtraction phase-contrast magnetic resonance imaging (PCMRI) noninvasive measurements of total liver blood flow (TLBF) and hepatic arterial (HA) flow have been validated in animal models and translated into normal volunteers, but not patients. This study aims to demonstrate its use in patients with liver cirrhosis, evaluate measurement consistency, correlate measurements with portal hypertension severity, and invasively validate TLBF measurements.

MATERIALS AND METHODS

Local research ethics committee approval was obtained. Twelve patients (mean, 50.8 ± 3.1 years; 10 men) with histologically confirmed cirrhosis were recruited prospectively, undergoing 2-dimensional PCMRI of the portal vein (PV) and the infrahepatic and suprahepatic inferior vena cava. Total liver blood flow and HA flow were estimated by subtracting infrahepatic from suprahepatic inferior vena cava flow and PV flow from estimated TLBF, respectively. Invasive hepatic venous pressure gradient (HVPG) and indocyanine green (ICG) clearance TLBF were measured within 7 days of PCMRI. Bland-Altman (BA) analysis of agreement, coefficients of variation, and Pearson correlation coefficients were calculated for comparisons with direct inflow PCMRI, HVPG, and ICG clearance.

RESULTS

The mean difference between caval subtraction TLBF and direct inflow PCMRI was 6.3 ± 4.2 mL/min/100 g (BA 95% limits of agreement, ±28.7 mL/min/100 g). Significant positive correlations were observed between HVPG and caval subtraction HA fraction (r = 0.780, P = 0.014), but not for HA flow (r = 0.625, P = 0.053), PV flow (r = 0.244, P = 0.469), or caval subtraction TLBF (r = 0.473, P = 0.141). Caval subtraction and ICG TLBF agreement was modest (mean difference, -32.6 ± 16.6 mL/min/100 g; BA 95% limits of agreement, ±79.7 mL/min/100 g), but coefficients of variation were not different (65.7% vs 48.1%, P = 0.28).

CONCLUSIONS

In this proof-of-principle study, caval subtraction PCMRI measurements are consistent with direct inflow PCMRI, correlate with portal hypertension severity, and demonstrate modest agreement with invasive TLBF measurements. Larger studies investigating the clinical role of TLBF and HA flow measurement in patients with liver disease are justified.

Improved hepatic arterial fraction estimation using cardiac output correction of arterial input functions for liver DCE MRI

Liver dynamic contrast enhanced (DCE) MRI pharmacokinetic modelling could be useful in the assessment of diffuse liver disease and focal liver lesions, but is compromised by errors in arterial input function (AIF) sampling. In this study, we apply cardiac output correction to arterial input functions (AIFs) for liver DCE MRI and investigate the effect on dual-input single compartment hepatic perfusion parameter estimation and reproducibility.

Thirteen healthy volunteers (28.7  ±  1.94 years, seven males) underwent liver DCE MRI and cardiac output measurement using aortic root phase contrast MRI (PCMRI), with reproducibility (n  =  9) measured at 7 d. Cardiac output AIF correction was undertaken by constraining the first pass AIF enhancement curve using the indicator-dilution principle. Hepatic perfusion parameters with and without cardiac output AIF correction were compared and 7 d reproducibility assessed.

Differences between cardiac output corrected and uncorrected liver DCE MRI portal venous (PV) perfusion (p  =  0.066), total liver blood flow (TLBF) (p  =  0.101), hepatic arterial (HA) fraction (p  =  0.895), mean transit time (MTT) (p  =  0.646), distribution volume (DV) (p  =  0.890) were not significantly different. Seven day corrected HA fraction reproducibility was improved (mean difference 0.3%, Bland–Altman 95% limits-of-agreement (BA95%LoA)  ±27.9%, coefficient of variation (CoV) 61.4% versus 9.3%, ±35.5%, 81.7% respectively without correction). Seven day uncorrected PV perfusion was also improved (mean difference 9.3 ml min⁻¹/100 g, BA95%LoA  ±506.1 ml min⁻¹/100 g, CoV 64.1% versus 0.9 ml min⁻¹/100 g, ±562.8 ml min⁻¹/100 g, 65.1% respectively with correction) as was uncorrected TLBF (mean difference 43.8 ml min⁻¹/100 g, BA95%LoA  ±586.7 ml min⁻¹/ 100 g, CoV 58.3% versus 13.3 ml min⁻¹/100 g, ±661.5 ml min⁻¹/100 g, 60.9% respectively with correction). Reproducibility of uncorrected MTT was similar (uncorrected mean difference 2.4 s, BA95%LoA  ±26.7 s, CoV 60.8% uncorrected versus 3.7 s, ±27.8 s, 62.0% respectively with correction), as was and DV (uncorrected mean difference 14.1%, BA95%LoA  ±48.2%, CoV 24.7% versus 10.3%, ±46.0%, 23.9% respectively with correction).

Cardiac output AIF correction does not significantly affect the estimation of hepatic perfusion parameters but demonstrates improvements in normal volunteer 7 d HA fraction reproducibility, but deterioration in PV perfusion and TLBF reproducibility. Improved HA fraction reproducibility maybe important as arterialisation of liver perfusion is increased in chronic liver disease and within malignant liver lesions.

Vascular assessment of liver disease-towards a new frontier in MRI

Complex haemodynamic phenomena underpin the pathophysiology of chronic liver disease. Non-invasive MRI-based assessment of hepatic vascular parameters therefore has the potential to yield meaningful biomarkers for chronic liver disease. In this review, we provide an overview of vascular sequelae of chronic liver disease amenable to imaging evaluation and describe the current supportive evidence, strengths and the limitations of MRI methodologies, including dynamic contrast-enhanced, dynamic hepatocyte-specific contrast-enhanced, phase-contrast, arterial spin labelling and MR elastography in the assessment of hepatic vascular parameters. We review the broader challenges of quantitative hepatic vascular MRI, including the difficulties of motion artefact, complex post-processing, long acquisition times, validation and limitations of pharmacokinetic models, alongside the potential solutions that will shape the future of MRI and deliver this new frontier to the patient bedside.

Acute-on-chronic liver failure: Pathogenesis, prognostic factors and management

Acute-on-chronic liver failure (ACLF) is increasingly recognized as a complex syndrome that is reversible in many cases. It is characterized by an acute deterioration of liver function in the background of a pre-existing chronic liver disease often associated with a high short-term mortality rate. Organ failure (OF) is always associated, and plays a key role in determining the course, and the outcome of the disease. The definition of ACLF remains controversial due to its overall ambiguity, with several disparate criteria among various associations dedicated to the study of liver diseases. Although the precise pathogenesis needs to be clarified, it appears that an altered host response to injury might be a contributing factor caused by immune dysfunction, ultimately leading to a pro-inflammatory status, and eventually to OF. The PIRO concept (Predisposition, Insult, Response and Organ Failure) has been proposed to better approach the underlying mechanisms. It is accepted that ACLF is a different and specific form of liver failure, where a precipitating event is always involved, even though it cannot always be ascertained. According to several studies, infections and active alcoholism often trigger ACLF. Viral hepatitis, gastrointestinal haemorrhage, or drug induced liver injury, which can also provoke the syndrome. This review mainly focuses on the physiopathology and prognostic aspects. We believe these features are essential to further understanding and providing the rationale for improveddisease management strategies.

Acute-on-chronic liver failure

Acute-on-chronic liver failure combines an acute deterioration in liver function in an individual with pre-existing chronic liver disease and hepatic and extrahepatic organ failures, and is associated with substantial short-term mortality. Common precipitants include bacterial and viral infections, alcoholic hepatitis, and surgery, but in more than 40% of patients, no precipitating event is identified. Systemic inflammation and susceptibility to infection are characteristic pathophysiological features. A new diagnostic score, the Chronic Liver Failure Consortium (CLIF-C) organ failure score, has been developed for classification and prognostic assessment of patients with acute-on-chronic liver failure. Disease can be reversed in many patients, and thus clinical management focuses upon the identification and treatment of the precipitant while providing multiorgan-supportive care that addresses the complex pattern of physiological disturbance in critically ill patients with liver disease. Liver transplantation is a highly effective intervention in some specific cases, but recipient identification, organ availability, timing of transplantation, and high resource use are barriers to more widespread application. Recognition of acute-on-chronic liver failure as a clinically and pathophysiologically distinct syndrome with defined diagnostic and prognostic criteria will help to encourage the development of new management pathways and interventions to address the unacceptably high mortality.

Endothelial dysfunction in cirrhosis: Role of inflammation and oxidative stress

This review describes the recent developments in the pathobiology of endothelial dysfunction (ED) in the context of cirrhosis with portal hypertension and defines novel strategies and potential targets for therapy. ED has prognostic implications by predicting unfavourable early hepatic events and mortality in patients with portal hypertension and advanced liver diseases. ED characterised by an impaired bioactivity of nitric oxide (NO) within the hepatic circulation and is mainly due to decreased bioavailability of NO and accelerated degradation of NO with reactive oxygen species. Furthermore, elevated inflammatory markers also inhibit NO synthesis and causes ED in cirrhotic liver. Therefore, improvement of NO availability in the hepatic circulation can be beneficial for the improvement of endothelial dysfunction and associated portal hypertension in patients with cirrhosis. Furthermore, therapeutic agents that are identified in increasing NO bioavailability through improvement of hepatic endothelial nitric oxide synthase (eNOS) activity and reduction in hepatic asymmetric dimethylarginine, an endogenous modulator of eNOS and a key mediator of elevated intrahepatic vascular tone in cirrhosis would be interesting therapeutic approaches in patients with endothelial dysfunction and portal hypertension in advanced liver diseases.

Chronic Liver Failure-Sequential Organ Failure Assessment is better than the Asia-Pacific Association for the Study of Liver criteria for defining acute-on-chronic liver failure and predicting outcome

AIM

To compare the utility of the Chronic Liver Failure-Sequential Organ Failure Assessment (CLIF-SOFA) and Asia-Pacific Association for the Study of Liver (APASL) definitions of acute-on-chronic liver failure (ACLF) in predicting short-term prognosis of patients with ACLF.

METHODS

Consecutive patients of cirrhosis with acute decompensation were prospectively included. They were grouped into ACLF and no ACLF groups as per CLIF-SOFA and APASL criteria. Patients were followed up for 3 mo from inclusion or mortality whichever was earlier. Mortality at 28-d and 90-d was compared between no ACLF and ACLF groups as per both criteria. Mortality was also compared between different grades of ACLF as per CLIF-SOFA criteria. Prognostic scores like CLIF-SOFA, Acute Physiology and Chronic Health Evaluation (APACHE)-II, Child-Pugh and Model for End-Stage Liver Disease (MELD) scores were evaluated for their ability to predict 28-d mortality using area under receiver operating curves (AUROC).

RESULTS

Of 50 patients, 38 had ACLF as per CLIF-SOFA and 19 as per APASL criteria. Males (86%) were predominant, alcoholic liver disease (68%) was the most common etiology of cirrhosis, sepsis (66%) was the most common cause of acute decompensation while infection (66%) was the most common precipitant of acute decompensation. The 28-d mortality in no ACLF and ACLF groups was 8.3% and 47.4% (P = 0.018) as per CLIF-SOFA and 39% and 37% (P = 0.895) as per APASL criteria. The 28-d mortality in patients with no ACLF (n = 12), ACLF grade 1 (n = 11), ACLF grade 2 (n = 14) and ACLF grade 3 (n = 13) as per CLIF-SOFA criteria was 8.3%, 18.2%, 42.9% and 76.9% (χ(2) for trend, P = 0.002) and 90-d mortality was 16.7%, 27.3%, 78.6% and 100% (χ(2) for trend, P < 0.0001) respectively. Patients with prior decompensation had similar 28-d and 90-d mortality (39.3% and 53.6%) as patients without prior decompensation (36.4% and 63.6%) (P = NS). AUROCs for 28-d mortality were 0.795, 0.787, 0.739 and 0.710 for CLIF-SOFA, APACHE-II, Child-Pugh and MELD scores respectively. On multivariate analysis of these scores, CLIF-SOFA was the only significant independent predictor of mortality with an odds ratio 1.538 (95%CI: 1.078-2.194).

CONCLUSION

CLIF-SOFA criteria is better than APASL criteria to classify patients into ACLF based on their prognosis. CLIF-SOFA score is the best predictor of short-term mortality.

Acute-on-chronic liver failure: a review

There is no universally accepted definition of acute-on-chronic liver failure; however, it is recognized as an entity characterized by decompensation from an underlying chronic liver disease associated with organ failure that conveys high short-term mortality, with alcoholism and infection being the most frequent precipitating events. The pathophysiology involves inflammatory processes associated with a trigger factor in susceptible individuals (related to altered immunity in the cirrhotic population). This review addresses the different definitions developed by leading research groups, epidemiological and pathophysiological aspects, and the latest treatments for this entity.

Hepatic and systemic hemodynamic derangements predict early mortality and recovery in patients with acute-on-chronic liver failure

BACKGROUND AND AIMS

Acute-on-chronic liver failure (ACLF) is a clinical entity where there is a potential for reversibility of hepatic dysfunction once the acute hepatic insult resolves. The portal and systemic hemodynamics in ACLF patients to study its relevance in determining the clinical outcomes was studied.

METHODS

Clinical, laboratory, portal, and systemic hemodynamic assessments were done at admission and after 3 months. Standard medical care was given to all the patients.

RESULTS

Fifty-seven patients with ACLF were enrolled, and they underwent baseline hepatic venous pressure gradient (HVPG) measurement. Twenty-six (46%) patients died during the 3-month follow-up. Presence of high HVPG and hepatic encephalopathy were found to be independent baseline predictors of mortality. Of the 31 surviving patients, 24 consented for a repeat HVPG. The baseline HVPG reduced from 16 (range 12-30) to 13 (range 6-21) mmHg; (P < 0.05). The reduction in HVPG correlated with clinical and biochemical recovery, and reduction in Child-Turcotte-Pugh score score (P < 0.05), while the aortic mean arterial pressure, cardiac index and systemic vascular resistance index improved significantly (< 0.05). Six (25%) patients developed upper gastrointestinal bleed; the median HVPG between bleeders and non-bleeders was not different possibly because of early onset of bleed (median 20 [15-45 days]).

CONCLUSIONS

Baseline HVPG is an independent predictor of mortality in ACLF patients. The portal and systemic circulatory anomalies regress substantially by 90 days and correlate with clinical recovery. However, in the initial phase, the raised portal pressure predisposes these patients to high risk of variceal bleeding.

FXR agonist INT-747 upregulates DDAH expression and enhances insulin sensitivity in high-salt fed Dahl rats

Aims

Genetic and pharmacological studies have shown that impairment of the nitric oxide (NO) synthase (NOS) pathway is associated with hypertension and insulin-resistance (IR). In addition, inhibition of NOS by the endogenous inhibitor, asymmetric dimethylarginine (ADMA), may also result in hypertension and IR. On the other hand, overexpression of dimethylarginine dimethylaminohydrolase (DDAH), an enzyme that metabolizes ADMA, in mice is associated with lower ADMA, increased NO and enhanced insulin sensitivity. Since DDAH carries a farnesoid X receptor (FXR)-responsive element, we aimed to upregulate its expression by an FXR-agonist, INT-747, and evaluate its effect on blood pressure and insulin sensitivity.

Methods and Results

In this study, we evaluated the in vivo effect of INT-747 on tissue DDAH expression and insulin sensitivity in the Dahl rat model of salt-sensitive hypertension and IR (Dahl-SS). Our data indicates that high salt (HS) diet significantly increased systemic blood pressure. In addition, HS diet downregulated tissue DDAH expression while INT-747 protected the loss in DDAH expression and enhanced insulin sensitivity compared to vehicle controls.

Conclusion

Our study may provide the basis for a new therapeutic approach for IR by modulating DDAH expression and/or activity using small molecules.