AKI in patients with acute on chronic liver failure is different from acute decompensation of cirrhosis

APASL clinical practice guidelines on the management of acute kidney injury in acute-on-chronic liver failure

Acute-on-chronic liver failure (ACLF) is a syndrome that is characterized by the rapid development of organ failures predisposing these patients to a high risk of short-term early death. The main causes of organ failure in these patients are bacterial infections and systemic inflammation, both of which can be severe. For the majority of these patients, a prompt liver transplant is still the only effective course of treatment. Kidneys are one of the most frequent extrahepatic organs that are affected in patients with ACLF, since acute kidney injury (AKI) is reported in 22.8-34% of patients with ACLF. Approach and management of kidney injury could improve overall outcomes in these patients. Importantly, patients with ACLF more frequently have stage 3 AKI with a low rate of response to the current treatment modalities. The objective of the present position paper is to critically review and analyze the published data on AKI in ACLF, evolve a consensus, and provide recommendations for early diagnosis, pathophysiology, prevention, and management of AKI in patients with ACLF. In the absence of direct evidence, we propose expert opinions for guidance in managing AKI in this very challenging group of patients and focus on areas of future research. This consensus will be of major importance to all hepatologists, liver transplant surgeons, and intensivists across the globe.

Active alcohol consumption is associated with acute-on-chronic liver failure in Hispanic patients

BACKGROUND

Acute-on-chronic liver failure (ACLF) is a severe clinical entity associated with elevated short-term mortality. We aimed to characterize patients with decompensated cirrhosis according to presence of ACLF, their association with active alcohol intake, and long-term survival in Latin America.

METHODS

Retrospective cohort study of decompensated cirrhotic in three Chilean university centers (2017-2019). ACLF was diagnosed according EASL-CLIF criteria. We assessed survival using competing-risk and time-to-event analyses. We evaluated the time to death using accelerated failure time (AFT) models.

RESULTS

We included 320 patients, median age of 65.3±11.7 years old, and 48.4% were women. 92 (28.7%) patients met ACLF criteria (ACLF-1: 29.3%, ACLF-2: 27.1%, and ACLF-3: 43.4%). The most common precipitants were infections (39.1%), and the leading organ failure was kidney (59.8%). Active alcohol consumption was frequent (27.7%), even in patients with a prior diagnosis of non-alcoholic fatty liver disease (NAFLD) (16.2%). Ninety-two (28.7%) patients had ACLF (ACLF-1: 8.4%, ACLF-2: 7.8%, and ACLF-3: 12.5%). ACLF patients had a higher MELD-Na score at admission (27 [22-31] versus 16 [12-21], p<0.0001), a higher frequency of alcohol-associated liver disease (36.7% versus 24.9%, p=0.039), and a more frequent active alcohol intake (37.2% versus 23.8%, p=0.019). In a multivariate model, ACLF was associated with higher mortality (subdistribution hazard ratio 1.735, 95%CI: 1.153-2.609; p<0.008). In the AFT models, the presence of ACLF during hospitalization correlated with a shorter time to death: ACLF-1 shortens the time to death by 4.7 times (time ratio [TR] 0.214, 95%CI: 0.075-0.615; p<0.004), ACLF-2 by 4.4 times (TR 0.224, 95%CI: 0.070-0.713; p<0.011), and ACLF-3 by 37 times (TR 0.027, 95%CI: 0.006-0.129; p<0.001).

CONCLUSIONS

Patients with decompensated cirrhosis and ACLF exhibited a high frequency ofactive alcohol consumption. Patients with ACLF showed higher mortality and shorter time todeath than those without ACLF.

Early Versus Standard Initiation of Terlipressin for Acute Kidney Injury in ACLF: A Randomized Controlled Trial (eTerli Study)

BACKGROUND AND AIMS

Terlipressin infusion is effective in hepatorenal syndrome (HRS-AKI). However, its efficacy for HRS-AKI resolution in acute-on-chronic liver failure (ACLF) patients has been suboptimal. Progression of AKI is rapid in ACLF. We investigated whether early initiation of terlipressin(eTerli) can improve response rates.

METHODS

Consecutive ACLF patients with stage II/III AKI despite albumin resuscitation (40 g) were randomized to receive terlipressin at 2 mg/24 h plus albumin at 12 h (ET, n = 35) or at 48 h as standard therapy (ST, n = 35). (June 22, 2020 to June 10, 2022). The primary end-point was AKI reversal by day7.

RESULTS

Baseline parameters including AKI stage and ACLF-AARC scores in two arms were comparable. Full AKI response at day 7 was higher in ET [24/35 (68.6%)] than ST arm [11/35 (31.4%; P 0.03]. Day3 AKI response was also higher in ET arm [11/35 (31.4%) vs. 4/35 (11.4%), P 0.04]. Using ST compared to ET [HR 4.3; P 0.026] and day 3 serum creatinine > 1.6 mg/dl [HR 9.1; AUROC-0.866; P < 0.001] predicted HRS-AKI non-response at day 7. ET patients showed greater improvement in ACLF grade, mean arterial pressure, and urine output at day 3, and required lower albumin within 7 days than ET arm (149.1 ± 41.8 g vs. 177.5 ± 40.3 g, P 0.006) and had lower 28-day mortality: 40% vs. 65.7%, P 0.031]. Early use of terlipressin than ST [HR 2.079; P 0.038], baseline HE [HR 2.929; P 0.018], and AKI persistence at day 3 [HR 1.369; P 0.011] predicted 28-day mortality. Fifteen (21.4%) patients had treatment related adverse effects, none was life threatening.

CONCLUSION

In ACLF patients, early initiation of terlipressin for AKI persisting after 12 h of volume expansion with albumin helps in reduced short-term mortality and early AKI reversal with regression of ACLF stage. These results indicate need for change in current practice for terlipressin usage in HRS-AKI.

Prospective validation of the EASL management algorithm for acute kidney injury in cirrhosis

BACKGROUND & AIMS

The management of acute kidney injury (AKI) in cirrhosis is challenging. The EASL guidelines proposed an algorithm for the management of AKI, but this has never been validated. We aimed to prospectively evaluate this algorithm in clinical practice.

METHODS

We performed a prospective cohort study in consecutive hospitalized patients with cirrhosis and AKI. The EASL management algorithm includes identification/treatment of precipitating factors, 2-day albumin infusion in patients with AKI ≥stage 1B, and treatment with terlipressin in patients with hepatorenal syndrome (HRS-AKI). The primary outcome was treatment response, which included both full and partial response. Secondary outcomes were survival and adverse events associated with terlipressin therapy.

RESULTS

A total of 202 AKI episodes in 139 patients were included. Overall treatment response was 80%, while renal replacement therapy was required in only 8%. Response to albumin infusion was achieved in one-third of episodes. Of patients not responding to albumin, most (74%) did not meet the diagnostic criteria of HRS-AKI, with acute tubular necrosis (ATN) being the most common phenotype. The response rate in patients not meeting the criteria for HRS-AKI was 70%. Only 30 patients met the diagnostic criteria for HRS-AKI, and their response rate to terlipressin was 61%. Median time from AKI diagnosis to terlipressin initiation was only 2.5 days. While uNGAL (urinary neutrophil gelatinase-associated lipocalin) could differentiate ATN from other phenotypes (AUROC 0.78), it did not predict response to therapy in HRS-AKI. Ninety-day transplant-free survival was negatively associated with MELD-Na, ATN and HRS-AKI as well as uNGAL. Three patients treated with terlipressin developed pulmonary edema.

CONCLUSIONS

The application of the EASL AKI algorithm is associated with very good response rates and does not significantly delay initiation of terlipressin therapy.

IMPACT AND IMPLICATIONS

The occurrence of acute kidney injury (AKI) in patients with cirrhosis is associated with poor short-term mortality. Improving its rapid identification and prompt management was the focus of the recently proposed EASL AKI algorithm. This is the first prospective study demonstrating that high AKI response rates are achieved with the use of this algorithm, which includes identification of AKI, treatment of precipitating factors, a 2-day albumin challenge in patients with AKI ≥1B, and supportive therapy in patients with persistent AKI not meeting HRS-AKI criteria or terlipressin with albumin in those with HRS-AKI. These findings support the use of this algorithm in clinical practice.

Non-resolution of acute kidney injury in the first week portends the development of chronic kidney disease in critically ill patients with cirrhosis

BACKGROUND

Renal tubular epithelial cells (RTECs) cause maladaptive repair and perpetuate renal fibrosis.

AIM

To evaluate urinary neutrophil gelatinase-associated lipocalin (NGAL) and RTEC as risk factors for non-resolution of acute kidney injury (AKI-NR) at day seven and chronic kidney disease (CKD) in critically ill patients with cirrhosis.

METHODS

We performed urinary NGAL and microscopy at enrolment and day 7 in all patients. We assessed 17 renal injury, endothelial injury and repair markers, genes for mitochondrial biogenesis by qRT-PCR in RTEC, and post-mortem renal biopsies for understanding mechanisms of AKI non-resolution (n = 30).

RESULTS

We enrolled 310 patients, aged 48.1 ± 11.6 years, 87% male, 90% alcoholic. Of these, 36% had RTEC at enrolment, and 53% had AKI-NR on day 7. On mean follow-up of 136 days (range 43-365), 150 (48.3%) developed CKD. The presence of RTEC or granular casts, NGAL and AKI-NR were independent predictors of CKD development on competing risk analysis. Higher MCP-1, renal endothelial injury, decrease in tubular repair markers and failure of mitochondrial biogenesis in RTEC were seen in patients with AKI-NR compared with AKI-R (p < 0.05). Renal biopsies showed infiltration with monocyte-macrophage, increased α-SMA, and tubulointerstitial fibrosis.

CONCLUSION

Almost two-thirds of critically ill patients with cirrhosis have AKI, which resolves in only one-half at day seven and predicts the development of CKD. Higher NGAL, RTEC, or granular casts were independent predictors of AKI-NR and CKD development. Enhanced tubular and endothelial injury, decreased repair, monocyte-macrophage infiltration and mitochondrial dysfunction in RTEC are associated with AKI non-resolution and risk of renal fibrosis.

Update on Assessment of Estimated Glomerular Filtration Rate in Patients With Cirrhosis

Kidney disease is associated with adverse outcomes in patients with cirrhosis including increased post-liver transplantation (LT) mortality. Therefore, diagnosis and staging of kidney disease are critical to timely implementation of treatment and have important implications for transplant eligibility. Serum creatinine (sCr) is a key component of the Model for End-Stage Liver Disease score in LT candidates, and sCr-based estimated glomerular filtration rate (eGFR) values play an important role in determining medical urgency for LT. However, the use of sCr to assess kidney function may be limited in the cirrhotic milieu due to decreased creatinine production, interference of bilirubin with some laboratory assays for sCr, and expansion of the volume of distribution of creatinine. Therefore, conventional eGFR equations perform poorly in patients with cirrhosis and may overestimate kidney function leading to delayed diagnosis of acute kidney injury or lower priority for LT in patients with a truly low glomerular filtration rate. In this review, we will provide an update on the use of sCr for diagnosis and staging of kidney disease in patients with cirrhosis, discuss the limitations of sCr-based eGFR equations, and discuss novel eGFR equations that have been developed in patients with cirrhosis.

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.

Tenofovir alafenamide versus entecavir for treating hepatitis B virus-related acute-on-chronic liver failure: real-world study

Background and aims

Real-world data regarding hepatitis B virus-related acute-on-chronic liver failure (HBV-ACLF) patients receiving tenofovir alafenamide (TAF) as an antiviral drug are limited. Hence, we evaluated the efficacy and kidney safety of TAF among this population.

Methods

A total of 272 HBV-related ACLF patients hospitalized at Xiangya Hospital of Central South University were enrolled in this retrospective research. All patients received antiviral therapy with TAF (n = 100) or ETV (n = 172) and comprehensive medical treatments.

Results

Through 1:1 propensity score matching, 100 patients were finally included in each group. At week 48, the survival rates without transplantation of the TAF group and ETV group were 76.00 and 58.00%, separately (P = 0.007). After 4 weeks of treatment, the TAF treatment group exhibited a significantly decline in HBV DNA viral load (P = 0.029). The mean estimated glomerular filtration rate was apparently improved in the TAF group compared with the ETV group (TAF 5.98 ± 14.46 vs. ETV 1.18 ± 18.07 ml/min/1.73 m²) (P < 0.05). There were 6 patients in TAF group and 21 patients in ETV group with chronic kidney disease (CKD) stage progression ≥ 1. By contrast, the ETV treatment group has a greater risk of renal function progression in CKD 1 stage patients (P < 0.05).

Conclusion

This real-world clinical study showed that TAF is more effective than ETV in reducing viral load and improving survival rate in HBV-ACLF patients and the risk of renal function decline is lower.

Clinical trial registration

https://ClinicalTrials.gov, identifier NCT05453448.

Acute kidney injury in patients with acute-on-chronic liver failure: clinical significance and management

Acute-on-chronic-liver failure (ACLF) refers to a phenomenon in which patients with chronic liver disease develop multiple organ failure due to acute exacerbation of underlying liver disease. More than 10 definitions of ACLF are extant around the world, and there is lack of consensus on whether extrahepatic organ failure is a main component or a consequence of ACLF. Asian and European consortiums have their own definitions of ACLF. The Asian Pacific Association for the Study of the Liver ACLF Research Consortium does not consider kidney failure as a diagnostic criterion for ACLF. Meanwhile, the European Association for the Study of the Liver Chronic Liver Failure and the North American Consortium for the Study of End-stage Liver Disease do consider kidney failure as an important factor in diagnosing and assessing the severity of ACLF. When kidney failure occurs in ACLF patients, treatment varies depending on the presence and stage of acute kidney injury (AKI). In general, the diagnosis of AKI in cirrhotic patients is based on the International Club of Ascites criteria: an increase of 0.3 mg/dL or more within 48 hours or a serum creatinine increase of 50% or more within one week. This study underscores the importance of kidney failure or AKI in patients with ACLF by reviewing its pathophysiology, prevention methods, and treatment approaches.

Quantitative plasma proteomics identifies metallothioneins as a marker of acute-on-chronic liver failure associated acute kidney injury

Background

Acute kidney injury (AKI) considerably increases the risk of short-term mortality in acute-on-chronic liver failure (ACLF) but predicting AKI is not possible with existing tools. Our study aimed at de novo discovery of AKI biomarkers in ACLF.

Methods

This observational study had two phases- (A) Discovery phase in which quantitative proteomics was carried-out with day-of-admission plasma from ACLF patients who initially had no-AKI but either progressed to AKI (n=10) or did not (n=9) within 7 days of admission and, (B) Validation phase in which selected biomarkers from the discovery phase were validated by ELISA in a larger set of ACLF plasma samples (n=93) followed by sub-group analyses.

Results

Plasma proteomics revealed 56 differentially expressed proteins in ACLF patients who progressed to AKI vs those who did not. The metallothionein protein-family was upregulated in patients who progressed to AKI and was validated by ELISA as significantly elevated in both- (i) ACLF-AKI vs no-AKI (p-value ≤ 0.0001) and (ii) progression to AKI vs no-progression to AKI (p-value ≤ 0.001). AUROC for AKI vs no-AKI was 0.786 (p-value ≤0.001) and for progression to AKI vs no-progression to AKI was 0.7888 (p-value ≤0.001). Kaplan-Meier analysis revealed that ACLF patients with plasma MT concentration >5.83 ng/mL had a high probability of developing AKI by day 7 (p-value ≤0.0001). High expression of metallothionein genes was found in post-mortem liver biopsies of ACLF patients.

Conclusion

Day-of-admission measurements of plasma metallothionein can act as predictive biomarkers of AKI in ACLF.

Natural history, spectrum and outcome of stage 3 AKI in patients with acute-on-chronic liver failure

BACKGROUND AND AIM

There is limited data on natural course and interventions in stage-3 acute kidney injury (AKI-3) in patients with acute-on-chronic liver failure (ACLF). We studied the factors of AKI-3 reversal and outcomes of dialysis in ACLF patients.

METHODS

Consecutive patients with ACLF were prospectively enrolled (n = 1022) and variables determining AKI and its outcomes were analysed.

RESULTS

At 1 month, 337 (33%) patients had AKI-3, of which, 131 had AKI-3 at enrolment and 206 developed AKI-3 during hospital stay. Of patients with AKI-3 at enrolment, 18% showed terlipressin response, 21% had AKI resolution and 59% required dialysis. High MELD (≥35) (model 1), serum bilirubin (≥23 mg/dL) (model 2) and AARC score (≥11) (model 3) were independent risk factors for dialysis. Dialysis was associated with worse survival in all AKI patients but improved outcomes in patients with AKI-3 (p = .022, HR 0.69 [0.50-0.95]). Post-mortem kidney biopsies (n = 61) revealed cholemic nephropathy (CN) in 54%, acute tubular necrosis (ATN) in 31%, and a combination (CN and ATN) in 15%. Serum bilirubin was significantly higher in patients with CN, CN and ATN compared with ATN respectively ([30.8 ± 12.2] vs. [26.7 ± 12.0] vs. [18.5 ± 9.8]; p = .002).

CONCLUSION

AKI-3 rapidly increases from 13% to 33% within 30 days in ACLF patients. Histopathological data suggested cholemic nephropathy as the predominant cause which correlated with high bilirubin levels. AKI-3 resolves in only one in five patients. Patients with AARC grade 3 and MELD >35 demand need for early dialysis in AKI-3 for improved outcomes.

Novel Biomarkers of AKI in Cirrhosis

Acute kidney injury (AKI) is a frequent complication in patients with cirrhosis that is associated with poor outcomes and decreased survival. The definition of AKI in cirrhosis is currently based on changes of serum creatinine levels with respect to baseline values. Differential diagnosis of the causes of AKI is of major relevance, considering that some causes of AKI, such as hepatorenal syndrome, have specific treatment options and different prognosis. Prediction of kidney function recovery and patients' survival is also crucial in this patient population to guide clinical decisions. AKI biomarkers in cirrhosis have emerged as a promising tool for differential diagnosis and prognosis in this situation. There are consistent data showing that some urine biomarkers, particularly neutrophil gelatinase-associated lipocalin, may be useful in daily clinical practice for the differential diagnosis of the cause of AKI in cirrhosis. AKI biomarkers may constitute a useful tool for use in differential diagnosis, prognosis of renal function, and survival in patients with cirrhosis. This review focuses on the current state of knowledge and future perspective of novel biomarkers of AKI in cirrhosis.

Hepatorenal syndrome in acute-on-chronic liver failure with acute kidney injury: more questions requiring discussion

In cirrhosis with ascites, hepatorenal syndrome (HRS) is a specific prerenal dysfunction unresponsive to fluid volume expansion. Acute-on-chronic liver failure (ACLF) comprises a group of clinical syndromes with multiple organ failure and early high mortality. There are differences in the characterization of ACLF between the Eastern and Western medical communities. Patients with ACLF and acute kidney injury (AKI) have more structural injuries, contributing to confusion in diagnosing HRS-AKI. In this review, we discuss progress in the pathogenesis, diagnosis, and management of HRS-AKI, especially in patients with ACLF. Controversy regarding HRS-AKI in ACLF and acute liver failure, hepatic carcinoma, shock, sepsis, and chronic kidney disease is also discussed. Research on the treatment of HRS-AKI with ACLF needs to be more actively pursued to improve disease prognosis.

Baseline serum cystatin C as a marker of acute kidney injury in patients with acute-on-chronic liver failure

BACKGROUND

A creatinine-based estimation of the renal function lags behind the onset of disease process. Cystatin C is a new marker for acute kidney injury (AKI). However, data are limited in patients with acute-on-chronic liver failure (ACLF). We evaluated serum cystatin C as an early predictor of AKI in patients with ACLF.

METHODS

In a prospective observational study, patients with ACLF and normal serum creatinine level were included in the study. Serum cystatin C was analyzed with the development of AKI and the disease outcome.

RESULT

Forty-seven patients (mean age: 43.26±16.34 years; male:female: 2.35:1) were included in the study. AKI developed in 34% of patients during the hospital stay. Receiver operating characteristic (ROC) curve analysis revealed that the best cutoff for baseline cystatin C was 1.47 mg/L with a sensitivity of 0.94 and specificity of 0.68. The cystatin C ((area under the curve [AUC]=0.853) performance was better than that of the creatinine (AUC=0.699), Child-Turcotte-Pugh (CTP) (AUC=0.661), and model for end-stage liver disease-sodium (MELD-Na) (AUC=0.641). In the univariate analysis, age, platelet count, creatinine, estimated glomerular filtration rate (eGFR)-modification of diet in renal disease (MDRD), cystatin C, and estimated glomerular filtration rate-serum cystatin C (eGFRcysC) were significantly associated with AKI in ACLF patients. Cystatin C was an independent positive predictor of AKI. Cystatin C was positively correlated with the MELD-Na scores (r=0.374 and p=0.009).

CONCLUSION

Our study supports previous studies reporting that serum cystatin C is a better predictor for AKI development compared to serum creatinine. Cystatin C may be used as an early marker for new-onset AKI in hospitalized patients with ACLF.

Establishment of a murine model of acute-on-chronic liver failure with multi-organ dysfunction

BACKGROUND AND AIMS

Acute-on-chronic liver failure (ACLF) is a distinct clinical entity with high probability of organ failure and mortality. Since patients generally present late, experimental models are needed to understand the pathophysiology and natural course of the disease.

METHODOLOGY

To reproduce the syndrome of ACLF, chronic liver disease was induced in C57BL6 mice (6-8 weeks; approximately 20-24 g weight) by intraperitoneal administration of carbon tetrachloride (CCl₄) for 10 weeks followed by an acute injury with acetaminophen (APAP) and lipopolysaccharide (LPS). Blood, ascitic fluid, and organs were collected to study cell death, regeneration, and fibrosis.

RESULTS

At 24 h post-APAP/LPS infusion, the liver tissue showed increased hepatocyte ballooning and endothelial cell TUNEL positivity. This was followed by progressive hepatocyte necrosis from perivascular region at day 7 to lobular region by day 11. ACLF (day 7 and day 11) animals showed increase in bilirubin (p < 0.05), prothrombin time (p < 0.0001), blood ammonia (p < 0.001), and portal pressure post-acute hepatocellular injury similar to human ACLF. Ascites was noticed by day 11 with median serum-ascites albumin gradient of 1.2 (1.1-1.3) g/dL. In comparison to cirrhosis, ACLF group (day 7 and day 11) showed significant decrease in Sirius red (p ≤ 0.0001), collagen1 (p < 0.0001), and a-SMA proportionate area (p < 0.0001) with loss of hepatocytes regeneration (p < 0.005). At day 11, ACLF animals also showed significant increase in serum creatinine (p < 0.05) and acute tubular necrosis suggestive of organ failure, compared to cirrhotic animals.

CONCLUSION

The CCL4/APAP/LPS (CALPS) model of ACLF mimics the clinical, biochemical, and histological features of ACLF with demonstrable progressive hepatocellular necrosis, liver failure, impaired regeneration, development of portal hypertension, and organ dysfunction in an animal with chronic liver disease.

Current knowledge about biomarkers of acute kidney injury in liver cirrhosis

Acute kidney injury (AKI) is common in advanced cirrhosis. Prerenal azotemia, hepatorenal syndrome, and acute tubular necrosis are the main causes of AKI in patients with cirrhosis. Evaluation of renal function and differentiation between functional and structural kidney injury are important issues in the management of cirrhosis. However, AKI in cirrhosis exists as a complex clinical spectrum rather than concrete clinical entity. Based on current evidence, changes in serum creatinine (Cr) levels remain the most appropriate standard for defining AKI in cirrhosis. However, serum Cr has a limited role in assessing renal function in this population. This review examines previous studies that investigated the ability of recent biomarkers for AKI in cirrhosis from the perspective of earlier and accurate diagnosis, classification of AKI phenotype, and prediction of clinical outcomes. Serum cystatin C and urine neutrophil gelatinase-associated lipocalin have been extensively studied in cirrhosis, and have facilitated improved diagnosis and prognosis prediction in patients with AKI. In addition, urine N-acetyl-β-D-glucosaminidase, interleukin 18, and kidney injury molecule 1 are other promising biomarkers for advanced cirrhosis. However, the clinical significance of these markers remains unclear because there are no cut-off values defining the normal range and differentiating phenotypes of AKI. In addition, AKI has been defined in terms of serum Cr, and renal biopsy-the gold standard-has not been carried out in most studies. Further discovery of innovate biomarkers and incorporation of various markers could improve the diagnosis and prognosis prediction of AKI, and will translate into meaningful improvements in patient outcomes.

Prevalence and short-term outcome of acute kidney injury in patients with acute-on-chronic liver failure: A meta-analysis

Acute kidney injury (AKI) in patients with acute-on-chronic liver failure (ACLF) is a distinct syndrome to that in patients with cirrhosis, yet is less characterized. The aim of this meta-analysis was to investigate the impact of AKI on outcome of ACLF. We searched PubMed, Web of Science and Cochrane Library for original articles that evaluated the impact of AKI on outcome of ACLF from 2011 to 2019. Odds ratio (OR) with 95% confidence interval (CI) for 1-month and 3-month mortality was calculated. The response rate of vasoconstrictor for hepatorenal syndrome (HRS)-AKI was assessed. Eight relevant articles with 3610 patients were included. The prevalence of AKI in ACLF patients was 41% (95% CI 32%-50%). The presence of AKI was significantly associated with 1-month mortality of ACLF (OR 3.98, 95% CI 3.09-5.12; P < .001) and 3-month mortality (OR 4.98, 95% CI 3.59-6.92; P < .001). Additionally, patients with AKI stage ≥2 showed a higher 3-month mortality than stage 1 (OR 3.89, 95% CI 2.60-5.82; P < .001), and those of stage 3 had a higher mortality than stage ≤2 (OR 3.77, 95% CI 2.10-6.77; P < .001). The pooled response rate of vasoconstrictors was 32% (95% CI 26%-37%). This meta-analysis indicated that about 40% of ACLF patients complicated with AKI and the presence of AKI substantially increased the short-term mortality, together with a poor response rate of vasoconstrictors for HRS-AKI.

Incidence, Mortality and Predictors of Acute Kidney Injury in Patients with Cirrhosis: A Systematic Review and Meta-analysis

Background and Aims: Acute kidney injury (AKI) is common in patients with cirrhosis but the incidence is heterogeneous among studies. We performed a meta-analysis to describe the incidence of AKI and its impact on patient mortality in patients with cirrhosis. We also evaluated the admission variables predicting development of AKI. Methods: A systematic search of various databases was performed up to November 2018. Meta-analyses were performed using random effects models. Results: Of 18,474 patients with cirrhosis from 30 selected studies, 5,648 developed AKI, with a pooled incidence of 29% (95% confidence interval [CI]: 28-30%, I ² of 99%). In-hospital mortality assessed in eight studies was six-fold higher among AKI patients, as compared to those without AKI (odds ratio [OR] 6.72, 95% CI: 3.47-13, p<0.0001, I ² of 70%). Three studies on patients admitted to intensive care showed about six-fold higher mortality among AKI patients (OR 5.90, 95% CI: 3.21-10.85, p>0.0001). Mortality remained significantly high, at days 30 and 90 and even at 1-year follow up after development of AKI. Of 12 admission variables analyzed, model for end-stage liver disease score, Child-Pugh-Turcotte stage C, presence of ascites, and presence of sepsis/septic shock were statistically significant risk factors for AKI. Conclusions: AKI occurred in about 29% of patients with cirrhosis and is associated with a six-fold increased risk of in-hospital mortality. Mortality remained high even in long-term follow-up of 1 year. Patients at risk for AKI development can be recognized at admission. Prospective studies are needed to develop strategies for improving outcome of these patients.

Incidence, Risk Factors, and Outcomes of Transition of Acute Kidney Injury to Chronic Kidney Disease in Cirrhosis: A Prospective Cohort Study

Transition to chronic kidney disease (CKD) after an episode of acute kidney injury (AKI) is known in patients without cirrhosis. We studied the incidence and risk factors for development of CKD in patients with cirrhosis. Competing risk analysis was performed to identify risk factors for CKD development. Of 818 patients with cirrhosis (age, 50.4 ± 11.8 years; 84% males; Model for End-Stage Liver Disease [MELD], 19.9 ± 9.9), 36% had AKI at enrollment, 27% had previous AKI, and 61% developed new episodes of AKI during the follow-up period. CKD developed in 269 (33%) patients. Serum cystatin C (CysC; subdistribution hazard ratio [SHR], 1.58; 1.07-2.33), episodes of previous AKI (SHR, 1.26; 1.02-1.56), and AKI stage at enrollment (no AKI [SHR, 1] vs. stage 1 [SHR, 3.28; 1.30-8.25] vs. stage 2 [SHR, 4.33; 1.76-10.66] vs. stage 3 [SHR, 4.5; 1.59-12.73]) were identified as baseline risk factors for CKD development. On time-varying competing risk analysis, MELD (SHR, 1.01; 1.00-1.03), number of AKI episodes (SHR, 1.25; 1.15-1.37), and CysC (SHR, 1.38; 1.01-1.89) predicted CKD development. Development of CKD was associated with higher risk of death. Reduction in glomerular filtration rate (GFR) not meeting CKD criteria was observed in 66% of patients with cirrhosis, more so in those with previous AKI episodes and a high CysC level and MELD score. Renal histology, available in 55 patients, showed tubulointerstitial injury in 86%, cholemic nephrosis in 29%, and glomerular changes in 38%. Conclusion: Almost two-thirds of patients with cirrhosis develop episodes of AKI and reduction in GFR; one-third progress to CKD, resulting in adverse outcomes. Higher MELD and CysC levels and number of AKI episodes predict development of CKD in patients with cirrhosis.

Terlipressin Is Superior to Noradrenaline in the Management of Acute Kidney Injury in Acute on Chronic Liver Failure

Hepatorenal syndrome (HRS) carries a high short-term mortality in patients with cirrhosis and acute on chronic liver failure (ACLF). Terlipressin and noradrenaline are routinely used in cirrhosis with HRS and have been found to be equally effective. There are no data comparing the efficacy of terlipressin with noradrenaline in ACLF patients with HRS. In an open-label, randomized controlled trial (RCT), consecutive patients with ACLF diagnosed with HRS acute kidney injury (AKI) were randomized to albumin with infusion of terlipressin (2-12 mg/day; n = 60) or noradrenaline (0.5-3.0 mg/h; n = 60). Response to treatment, course of AKI, and outcome were studied. Baseline characteristics, including AKI stage and sepsis-related HRS-AKI, were comparable between groups. Compared to noradrenaline, terlipressin achieved greater day 4 (26.1% vs. 11.7%; P = 0.03) and day 7 (41.7% vs. 20%; P = 0.01) response. Reversal of HRS was also better with terlipressin (40% vs. 16.7%; P = 0.004), with a significant reduction in the requirement of renal replacement therapy (RRT; 56.6% vs. 80%; P = 0.006) and improved 28-day survival (48.3% vs. 20%; P = 0.001). Adverse events limiting use of drugs were higher with terlipressin than noradrenaline (23.3% vs. 8.3%; P = 0.02), but were reversible. On multivariate analysis, high Model for End-Stage Liver Disease (MELD; odds ratio [OR], 1.10; confidence interval [CI] = 1.009-1.20; P = 0.03) and noradrenaline compared to terlipressin (OR, 3.05; CI = 1.27-7.33; P = 0.01) predicted nonresponse to therapy. Use of noradrenaline compared to terlipressin was also predictive of higher mortality (hazard ratio [HR], 2.08; CI = 1.32-3.30; P = 0.002). Conclusion: AKI in ACLF carries a high mortality. Infusion of terlipressin gives earlier and higher response than noradrenaline, with improved survival in ACLF patients with HRS-AKI.

Acute-on-chronic liver failure: Objective admission and support criteria in the intensive care unit

Cirrhosis is a leading cause of morbidity and mortality throughout the world. Significant complications include variceal bleeding, hepatic encephalopathy, hepatorenal syndrome, and infection. When these complications are severe, admission to the intensive care unit (ICU) is often required for organ support and management. Intensive care therapy can also serve as a bridge to liver transplantation. Along with decompensation of cirrhosis, the concept of acute-on-chronic liver failure (ACLF) has emerged. This involves an acute precipitating event, such as the development of infection in a patient with cirrhosis, which leads to acute deterioration of hepatic function and extrahepatic organ failure. Extrahepatic complications often include renal, cardiovascular, and respiratory failures. Patients with significant extrahepatic and hepatic failures need ICU admission for organ support. Again, in patients who are deemed suitable liver transplant candidates, intensive care management may allow bridging to liver transplantation. However, patients with a Chronic Liver Failure Consortium ACLF score greater than 70 at 48 to 72 hours post-ICU admission do not seem to benefit from ongoing intensive support and a palliative approach may be more appropriate.

Acute Kidney Injury at Admission Is a Better Predictor of Mortality than Its Persistence at 48 h in Patients with Acute-on-chronic Liver Failure

Background and Aims: Acute kidney injury (AKI) occurs commonly in patients with acute-on-chronic liver failure (ACLF). However, there are scant data regarding the impact of AKI on survival in ACLF. We performed a prospective study to evaluate the impact of AKI on survival in ACLF.

Methods: This study was conducted in ACLF patients hospitalized in the Gastroenterology Department of Sriram Chandra Bhanja Medical College (India) between October 2016 and February 2018. Demographic, clinical and laboratory parameters were recorded, and outcomes were compared between patients with and without AKI and between patients with persistent AKI and AKI reversal at 48 h.

Results: We screened 439 chronic liver disease patients as per the Asian Pacific Association for the Study of the Liver criteria and found that 113 (25.7%) of them had ACLF and 78 (69%) of them had AKI as per the Acute Kidney Injury Network criteria. ACLF patients with AKI had reduced 28-day survival (44.9% vs. 74.3%; p = 0.004) and 90-day survival (25.6% vs. 51.4%; p = 0.007), in comparison to ACLF patients without AKI. However, when comparison was made between AKI reverters and AKI persisters at 48 h, survival was comparable for both at 28 days and 90 days. Further, about one-tenth of ACLF patients with AKI died within 48 h of hospitalization.

Conclusions: Over two-thirds of ACLF patients had AKI. Although ACLF itself is a predictor of reduced survival, a very small increase in serum creatinine further worsens survival. Importantly, AKI at admission is a better predictor of early mortality in ACLF patients since recovery from AKI at 48 h does not improve survival.

Acute-on-Chronic Liver Failure: Getting Ready for Prime Time?

Acute on chronic liver failure (ACLF) is the culmination of chronic liver disease and extrahepatic organ failures, which is associated with a high short-term mortality and immense health care expenditure. There are varying definitions for organ failures and ACLF in Europe, North America, and Asia. These differing definitions need to be reconciled to enhance progress in the field. The pathogenesis of ACLF is multifactorial and related to interactions between the immunoinflammatory system, microbiota, and the various precipitating factors. Individual organ failures related to the kidney, brain, lungs, and circulation have cumulative adverse effects on mortality and are often complicated or precipitated by infections. Strategies to prevent and rapidly treat these organ failures are paramount in improving survival. With the aging population and paucity of organs for liver transplant, the prognosis of ACLF patients is poor, highlighting the need for novel therapeutic strategies. The role of liver transplant in ACLF is evolving and needs further investigation across large consortia. A role for early palliative care and management of frailty as approaches to alleviate disease burden and improve patient-reported outcomes is being increasingly recognized.

CONCLUSION

ACLF is a clinically relevant syndrome that is epidemic worldwide and requires a dedicated multinational approach focused on prognostication and management; investigations are underway worldwide to prepare ACLF for prime time. (Hepatology 2018; 00:000-000).

Profile, risk factors and outcome of acute kidney injury in paediatric acute-on-chronic liver failure

BACKGROUND & AIMS

There are no studies on acute kidney injury in paediatric acute-on-chronic liver failure. This study was planned with aim to describe the clinical presentation and outcome of acute kidney injury among paediatric acute-on-chronic liver failure patients.

METHODS

Data of all children 1-18 years of age presenting with acute chronic liver failure (Asia pacific association for the study of the liver definition) was reviewed. Acute kidney injury was defined as per Kidney Diseases-Improving Global Outcomes guidelines. Poor outcome was defined as death or need for liver transplant within 3 months of development of acute kidney injury.

RESULTS

A total of 84 children with acute-on-chronic liver failure were presented to us in the study period. Acute kidney injury developed in 22.6% of patients with acute-on-chronic liver failure. The median duration from acute-on-chronic liver failure to development of acute kidney injury was 4 weeks (Range: 2-10 weeks). The causes of acute kidney injury were hepatorenal syndrome (31.6%), sepsis (31.6%), nephrotoxic drugs (21%), dehydration (10.5%) and bile pigment related acute tubular necrosis in one patient. On univariate analysis, higher baseline bilirubin, higher international normalized ratio, higher paediatric end stage liver disease, presence of systemic inflammatory response syndrome and presence of spontaneous bacterial peritonitis had significant association with presence of acute kidney injury. On logistic regression analysis, presence of systemic inflammatory response syndrome (adjusted OR: 8.659, 95% CI: 2.18-34.37, P = .002) and higher baseline bilirubin (adjusted OR: 1.07, 95% CI: 1.008-1.135, P = .025) were independently associated with presence of acute kidney injury. Of the patients with acute kidney injury, 5(26.3%) survived with native liver, 10(52.6%) died and 4 (21.1%) underwent liver transplantation.

CONCLUSION

Acute kidney injury developed in 22.6% of children with acute-on-chronic liver failure. Bilirubin more than 17.7 mg/dL and presence of systemic inflammatory response syndrome were high risk factors for acute kidney injury. Development of acute kidney injury in a child with acute-on-chronic liver failure suggests poor outcome and need for early intervention.

Acute kidney injury in acute-on-chronic liver failure is different from in decompensated cirrhosis

AIM

To evaluate the differences in acute kidney injury (AKI) between acute-on-chronic liver failure (ACLF) and decompensated cirrhosis (DC) patients.

METHODS

During the period from December 2015 to July 2017, 280 patients with hepatitis B virus (HBV)-related ACLF (HBV-ACLF) and 132 patients with HBV-related DC (HBV-DC) who were admitted to our center were recruited consecutively into an observational study. Urine specimens were collected from all subjects and the levels of five urinary tubular injury biomarkers were detected,including neutrophil gelatinase-associated lipocalin (NGAL), interleukin-18 (IL-18), liver-type fatty acid binding protein (L-FABP), cystatin C (CysC), and kidney injury molecule-1 (KIM-1). Simultaneously, the patient demographics, occurrence and progression of AKI, and response to terlipressin therapy were recorded. All patients were followed up for 3 mo or until death after enrollment.

RESULTS

AKI occurred in 71 and 28 of HBV-ACLF and HBV-DC patients, respectively (25.4% vs 21.2%, P = 0.358). Among all patients, the levels of four urinary biomarkers (NGAL, CysC, L-FABP, IL-18) were significantly elevated in patients with HBV-ACLF and AKI (ACLF-AKI), compared with that in patients with HBV-DC and AKI (DC-AKI) or those without AKI. There was a higher proportion of patients with AKI progression in ACLF-AKI patients than in DC-AKI patients (49.3% vs 17.9%, P = 0.013). Forty-three patients with ACLF-AKI and 19 patients with DC-AKI were treated with terlipressin. The response rate of ACLF-AKI patients was significantly lower than that of patients with DC-AKI (32.6% vs 57.9%, P = 0.018). Furthermore, patients with ACLF-AKI had the lowest 90 d survival rates among all groups (P < 0.001).

CONCLUSION

AKI in ACLF patients is more likely associated with structural kidney injury, and is more progressive, with a poorer response to terlipressin treatment and a worse prognosis than that in DC patients.

AKI persistence at 48 h predicts mortality in patients with acute on chronic liver failure

BACKGROUND AND AIM

Management of acute kidney injury (AKI) in cirrhotics has undergone a paradigm change. We evaluated the impact of AKI persistence at 48 h on outcome in patients with acute on chronic liver failure (ACLF).

METHODS

Consecutive patients with ACLF (n = 373) were prospectively followed. AKI was defined as increase in serum creatinine of 0.3 mg/dl or 1.5- to 2-fold from baseline. Persistent AKI was defined as nonresponsive AKI at 48 h with respect to admission serum creatinine.

RESULTS

AKI at admission was present in 177 (47.5 %) patients. At 48 h, 73 % patients had persistent AKI and 27 % had responsive AKI. High Model for End-Stage Liver Disease (MELD) (≥26) [p, odds ratio (OR), 95 % confidence interval (CI)] [<0.001, 3.65 (2.1-3.67)], systemic inflammatory response syndrome (SIRS) [0.03, 1.6 (1.02-21.6)], and age (≥42 years) [0.03, 1.84 (1.19-2.85)] were significant predictors of AKI persistence. Persistent AKI was associated with significantly higher in-hospital mortality [p < 0.001, hazard ratio (HR) 1.7, 95 % CI 1.32-2.27]. We further found a lower cutoff for serum creatinine of 1.14 mg/dl at 48 h with better sensitivity of 61 %, specificity of 61 %, and likelihood ratio (LR+) of 1.6, correctly classifying 61 %, as against the conventional cutoff of 1.5 mg/dl with sensitivity of 37 %, specificity of 57 %, and LR+ of 3.3, correctly classifying 56 %. This new cutoff also predicted mortality with higher odds (OR 2.4, 95 % CI 1.3-4.8) as compared with the conventional cutoff (OR 2.1, 95 % CI 1.1-4.1).

CONCLUSION

AKI persistence at 48 h predicts mortality better than serum creatinine of 1.5 mg/dl in patients with ACLF. Serum creatinine value of 1.14 mg/dl and smaller increases in its value should be considered for risk stratification of patients with ACLF for interventional strategies.

Development of predisposition, injury, response, organ failure model for predicting acute kidney injury in acute on chronic liver failure

BACKGROUND AND AIM

There is limited data on predictors of acute kidney injury in acute on chronic liver failure. We developed a PIRO model (Predisposition, Injury, Response, Organ failure) for predicting acute kidney injury in a multicentric cohort of acute on chronic liver failure patients.

PATIENTS AND METHODS

Data of 2360 patients from APASL-ACLF Research Consortium (AARC) was analysed. Multivariate logistic regression model (PIRO score) was developed from a derivation cohort (n=1363) which was validated in another prospective multicentric cohort of acute on chronic liver failure patients (n=997).

RESULTS

Factors significant for P component were serum creatinine[(≥2 mg/dL)OR 4.52, 95% CI (3.67-5.30)], bilirubin [(<12 mg/dL,OR 1) vs (12-30 mg/dL,OR 1.45, 95% 1.1-2.63) vs (≥30 mg/dL,OR 2.6, 95% CI 1.3-5.2)], serum potassium [(<3 mmol/LOR-1) vs (3-4.9 mmol/L,OR 2.7, 95% CI 1.05-1.97) vs (≥5 mmol/L,OR 4.34, 95% CI 1.67-11.3)] and blood urea (OR 3.73, 95% CI 2.5-5.5); for I component nephrotoxic medications (OR-9.86, 95% CI 3.2-30.8); for R component,Systemic Inflammatory Response Syndrome,(OR-2.14, 95% CI 1.4-3.3); for O component, Circulatory failure (OR-3.5, 95% CI 2.2-5.5). The PIRO score predicted acute kidney injury with C-index of 0.95 and 0.96 in the derivation and validation cohort. The increasing PIRO score was also associated with mortality (P<.001) in both the derivation and validation cohorts.

CONCLUSIONS

The PIRO model identifies and stratifies acute on chronic liver failure patients at risk of developing acute kidney injury. It reliably predicts mortality in these patients, underscoring the prognostic significance of acute kidney injury in patients with acute on chronic liver failure.

Acute-on-chronic liver failure: recent update

Acute on chronic liver failure (ACLF) was first described in 1995 as a clinical syndrome distinct to classic acute decompensation. Characterized by complications of decompensation, ACLF occurs on a background of chronic liver dysfunction and is associated with high rates of organ failure and significant short-term mortality estimated between 45% and 90%. Despite the clinical relevance of the condition, it still remains largely undefined with continued disagreement regarding its precise etiological factors, clinical course, prognostic criteria and management pathways. It is concerning that, despite our relative lack of understanding of the condition, the burden of ACLF among cirrhotic patients remains significant with an estimated prevalence of 30.9%. This paper highlights our current understanding of ACLF, including its etiology, diagnostic and prognostic criteria and pathophysiology. It is evident that further refinement of the ACLF classification system is required in order to detect high-risk patients and improve short-term mortality rates. The field of metabolomics certainly warrants investigation to enhance diagnostic and prognostic parameters, while the use of granulocyte-colony stimulating factor is a promising future therapeutic intervention for patients with ACLF.

Kidney Injury in Liver Disease

Acute kidney injury (AKI) occurs frequently in patients with liver disease and increases morbidity and mortality. Hepatorenal syndrome is a common cause of AKI in patients with decompensated cirrhosis and is due to alterations in systemic and renal hemodynamics. Serum creatinine-based estimation of kidney function is a key component of the Model for End-stage Liver Disease score in liver transplant candidates. Continuous renal replacement therapy is used in critically ill patients with liver failure and AKI. Simultaneous liver-kidney transplantation (SLK) may be required in patients with liver failure and prolonged AKI. Identification of appropriate candidates for SLK remains controversial.

The Effect of Renal Function Impairment on the Mortality of Cirrhotic Patients: A Nationwide Population-Based 3-Year Follow-up Study

Renal function impairment (RFI) contributes to poor prognosis in cirrhotic patients. However, there have been no studies that seek to identify the effect of different types of RFI on the mortality of cirrhotic patients. We used the National Health Insurance Database, derived from the Taiwan National Health Insurance Program, to identify 44365 cirrhotic patients between January 1, 2007 and December 31, 2007. RFI was identified in 2832 cirrhotic patients, including 1075 with acute renal failure (ARF) (169 with hepatorenal syndrome, HRS; 906 with non-hepatorenal syndrome, NHRS), 705 with chronic kidney disease (CKD), and 1052 with end stage renal disease (ESRD). After Cox proportional hazard regression analysis adjusted by gender, age, and comorbid disorders, the 30-day, 30 to 90-day, 90-day to 1-year, and 1 to 3-year mortality hazard ratios (HR) compared to the non-RFI group were: (ARF) 5.19 (4.70-5.74), 3.23 (2.76-3.77), 1.51 (1.26-1.81), and 1.35 (1.13-1.61), respectively; (CKD) 2.70 (2.30-3.18), 2.03 (1.66-2.49), 1.60 (1.34-1.90), and 1.26 (1.06-1.49), respectively; and (ESRD) 1.42 (1.17-1.72), 1.62 (1.35-1.94), 1.90 (1.68-2.15), and 1.67 (1.48-1.89), respectively. Compared to NHRS, the 30-day, 30 to 90-day, 90-day to 1-year, and 1 to 3-year mortality HRs of HRS were 1.03 (0.80-1.32), 2.13 (1.46-3.11), 1.58 (0.90-2.75), and 2.51 (1.41-4.48), respectively, in cirrhotic patients with ARF. These results indicate the effects of CKD and ESRD on the mortality of cirrhotic patients are distributed equally in every survival stage, whereas the effect of ARF appears only in the early stage. Compared to NHRS, HRS contributes to a higher mortality risk at the late survival stage.