Renal dysfunction is common in patients undergoing liver transplant (LT) evaluation, thereby making it imperative for hepatologists to know how to diagnose, manage, and optimize treatment of acute kidney injury (AKI) and chronic kidney disease. This article reviews pre-transplant, peri-transplant, and post-transplant AKI diagnosis and management, and the role of renal replacement therapy in LT candidates.

Renal failure is a well-known and often devastating complication in patients with liver cirrhosis and contributes to significant morbidity and mortality.

This study aimed to evaluate the clinical profile and factors associated with the utilization of renal replacement therapy (RRT) requirement in cirrhotic patients presenting with AKI.

We conducted a retrospective cohort study of cirrhotic inpatient visits across all Northwell Health hospitals between January 1, 2019 and December 31, 2020. Patients meeting inclusion criteria were identified using the International Classification of Disease, tenth revision clinical modification (ICD-10-CM) codes. Clinical variables, including demographics, medical history, laboratory data, and outcomes, were collected. Statistical analyses were performed to compare variables between patients requiring RRT and those not requiring RRT.

Of 701 cirrhotic patient encounters, 516 met inclusion criteria. The most common etiology of AKI was pre-renal (45.3%), followed by hepatorenal syndrome (18.6%) and acute tubular necrosis (14.7%). Sixty patients (11.6%) required RRT, with worse outcomes observed in this group. Independent predictors of RRT requirement included hepatorenal syndrome, acute tubular necrosis, and pneumonia. Pre-renal AKI was associated with decreased likelihood of requiring RRT.

This study identified clinical and laboratory factors predicting RRT requirement in cirrhotic patients with AKI. Hepatorenal syndrome, acute tubular necrosis, and pneumonia were associated with increased likelihood of RRT. Understanding these predictors may aid in prognostication and management decisions for cirrhotic patients presenting with AKI, warranting further prospective validation studies.

Acute kidney injury (AKI) in patients with acute-on-chronic liver failure (ACLF) is driven by the severity of systemic inflammation, acute portal hypertension driving circulatory dysfunction, hyperbilirubinemia, and toxicity of bile acids. The spectrum is mostly structural, associated with reduced response to vasoconstrictors. The progression is rapid, and need of renal replacement therapy and extracorporeal therapies may be required for the management. The development of renal failure is usually considered when defining the syndrome of ACLF.

In the current review we discuss the pathophysiological basis, natural course, and response to the current therapeutic modalities and challenges in assessing and managing AKI in patients with ACLF. We conducted a comprehensive search of electronic databases such as PubMed, Web of Science, and Scopus using keywords like lactate, NGAL, and PHTN, as well as CRRT, PLEX, ACLF, and AKI phases for our review. Peer-reviewed English papers that addressed our issue were considered.

The difficulties and specific management strategies for AKI in ACLF patients are discussed emphasizing the importance of customized protocols, risk assessment guided by biomarkers, and investigation of extracorporeal therapies that target bile acids.

In 2023, Chinese Society of Hepatology of Chinese Medical Association convened a panel of experts to update the Chinese guidelines on the management of ascites and associated complications in cirrhosis which was launched in 2017 and renamed this guidelines as "Guidelines on the Management of Ascites in Cirrhosis." This comprehensive resource offers essential recommendations for the diagnosis and treatment of cirrhotic ascites, spontaneous bacterial peritonitis, and hepatorenal syndrome.

Patients with cirrhosis are prone to developing acute kidney injury (AKI), a complication associated with a markedly increased in-hospital morbidity and mortality, along with a risk of progression to chronic kidney disease. Whereas patients with cirrhosis are at increased risk of developing any phenotype of AKI, hepatorenal syndrome (HRS), a specific form of AKI (HRS-AKI) in patients with advanced cirrhosis and ascites, carries an especially high mortality risk. Early recognition of HRS-AKI is crucial since administration of splanchnic vasoconstrictors may reverse the AKI and serve as a bridge to liver transplantation, the only curative option. In 2023, a joint meeting of the International Club of Ascites (ICA) and the Acute Disease Quality Initiative (ADQI) was convened to develop new diagnostic criteria for HRS-AKI, to provide graded recommendations for the work-up, management and post-discharge follow-up of patients with cirrhosis and AKI, and to highlight priorities for further research.

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.

The purpose of this review is to describe an approach that emphasizes shared decision-making for patients with decompensated cirrhosis and acute kidney injury when liver transplantation is either not an option, or unlikely to be an option.

When acute kidney injury occurs on a background of decompensated cirrhosis, outcomes are generally poor. Providers can also be faced with prognostic uncertainty. A lack of guidance from nephrology and hepatology professional societies means that providers rely on expert opinion or institutional practice patterns.

For patients who are unlikely to receive liver transplantation, the occurrence of acute kidney injury represents an opportunity for a goals of care conversation. In this article, we share strategies through which providers can incorporate more shared decision-making when caring for these patients. The approach involves creating prognostic consensus amongst multidisciplinary teams and then relying on skilled communicators to share the prognosis. Palliative care consultation can be useful when teams need assistance in the conversations.

Acute kidney injury is a common complication of decompensated cirrhosis, frequently requires hospitalization, and carries a high short-term mortality. This population experiences several characteristic types of acute kidney injury: hypovolemic-mediated (prerenal), ischemic/nephrotoxic-mediated (acute-tubular necrosis), and hepatorenal syndrome. Prerenal acute kidney injury is treated with volume resuscitation. Acute-tubular necrosis is treated by optimizing perfusion pressure and discontinuing the offending agent. Hepatorenal syndrome, a unique physiology of decreased effective arterial circulation leading to renal vasoconstriction and ultimately acute kidney injury, is treated with plasma expansion with albumin and splanchnic vasoconstrictors such as terlipressin or norepinephrine. Common acute stressors such as bleeding, infection, and volume depletion often contribute to multifactorial acute kidney injury. Even with optimal medical management, many clinicians are faced with the challenge of initiating renal replacement therapy in these patients. This article reviews the epidemiology, indications, and complex considerations of renal replacement therapy for acute kidney injury in decompensated cirrhosis.

Hepatorenal syndrome (HRS) is a rare and highly morbid form of kidney injury unique to patients with decompensated cirrhosis. HRS is a physiologic consequence of portal hypertension, leading to a functional kidney injury that can be reversed by restoring effective circulating volume and renal perfusion. While liver transplantation is the only definitive "cure" for HRS, medical management with vasoconstrictors and i.v. albumin is a cornerstone of supportive care. Terlipressin, a V1a receptor agonist that acts on the splanchnic circulation, has been used for many years outside the United States for the treatment of HRS. However, its recent Food and Drug Administration approval has generated new interest in this population, as a new base of prescribers now work to incorporate the drug into clinical practice. In this article, we review HRS pathophysiology and diagnostic criteria, the clinical use of terlipressin and alternative therapies, and identify areas of future research in the space of HRS and kidney injury in cirrhosis.

Acute kidney injury (AKI) in cirrhosis is common and associated with high morbidity, but the incidence rates of different etiologies of AKI are not well described in the US. We compared incidence rates, practice patterns, and outcomes across etiologies of AKI in cirrhosis.

We performed a retrospective cohort study of 11 hospital networks, including consecutive adult patients admitted with AKI and cirrhosis in 2019. The etiology of AKI was adjudicated based on pre-specified clinical definitions (prerenal/hypovolemic AKI, hepatorenal syndrome [HRS-AKI], acute tubular necrosis [ATN], other).

A total of 2,063 patients were included (median age 62 [IQR 54-69] years, 38.3% female, median MELD-Na score 26 [19-31]). The most common etiology was prerenal AKI (44.3%), followed by ATN (30.4%) and HRS-AKI (12.1%); 6.0% had other AKI, and 7.2% could not be classified. In our cohort, 8.1% of patients received a liver transplant and 36.5% died by 90 days. The lowest rate of death was observed in patients with prerenal AKI (22.2%; p <0.001), while death rates were higher but not significantly different from each other in those with HRS-AKI and ATN (49.0% vs. 52.7%; p = 0.42). Using prerenal AKI as a reference, the adjusted subdistribution hazard ratio (sHR) for 90-day mortality was higher for HRS-AKI (sHR 2.78; 95% CI 2.18-3.54; p <0.001) and ATN (sHR 2.83; 95% CI 2.36-3.41; p <0.001). In adjusted analysis, higher AKI stage and lack of complete response to treatment were associated with an increased risk of 90-day mortality (p <0.001 for all).

AKI is a severe complication of cirrhosis. HRS-AKI is uncommon and is associated with similar outcomes to ATN. The etiology of AKI, AKI stage/severity, and non-response to treatment were associated with mortality. Further optimization of vasoconstrictors for HRS-AKI and supportive therapies for ATN are needed.

Acute kidney injury (AKI) in cirrhosis carries high morbidity, and management is determined by the etiology of injury. However, a large and well-adjudicated multicenter database from US centers that uses updated AKI definitions is lacking. Our findings demonstrate that acute tubular necrosis and hepatorenal syndrome have similar outcomes (∼50% mortality at 90 days), though hepatorenal syndrome is uncommon (12% of all AKI cases). These findings represent practice patterns at US transplant/tertiary centers and can be used as a baseline, presenting the situation prior to the adoption of terlipressin in the US.

Kidney disease in patients with liver disease is serious and increases mortality. Up to 50% of patients hospitalized experience an episode of acute kidney injury. In general, men with liver disease are thought to be at increased risk of kidney disease. However, this association should be considered with caution because most studies use creatinine-based inclusion criteria, which is negatively biased against women. In this review, we synthesize data on sex differences in kidney disease in patients with chronic liver disease in the clinical setting and discuss potential physiologic underpinnings.

In patients with cirrhosis and acute kidney injury (AKI), longer time to AKI-recovery may increase the risk of subsequent major-adverse-kidney-events (MAKE).

To examine the association between timing of AKI-recovery and risk of MAKE in patients with cirrhosis.

Hospitalised patients with cirrhosis and AKI (n = 5937) in a nationwide database were assessed for time to AKI-recovery and followed for 180-days. Timing of AKI-recovery (return of serum creatinine <0.3 mg/dL of baseline) from AKI-onset was grouped by Acute-Disease-Quality-Initiative Renal Recovery consensus: 0-2, 3-7, and >7-days. Primary outcome was MAKE at 90-180-days. MAKE is an accepted clinical endpoint in AKI and defined as the composite outcome of ≥25% decline in estimated-glomerular-filtration-rate (eGFR) compared with baseline with the development of de-novo chronic-kidney-disease (CKD) stage ≥3 or CKD progression (≥50% reduction in eGFR compared with baseline) or new haemodialysis or death. Landmark competing-risk multivariable analysis was performed to determine the independent association between timing of AKI-recovery and risk of MAKE.

4655 (75%) achieved AKI-recovery: 0-2 (60%), 3-7 (31%), and >7-days (9%). Cumulative-incidence of MAKE was 15%, 20%, and 29% for 0-2, 3-7, >7-days recovery groups, respectively. On adjusted multivariable competing-risk analysis, compared to 0-2-days, recovery at 3-7 and >7-days was independently associated with an increased risk for MAKE: sHR 1.45 (95% CI 1.01-2.09, p = 0.042), sHR 2.33 (95% CI 1.40-3.90, p = 0.001), respectively.

Longer time to recovery is associated with an increased risk of MAKE in patients with cirrhosis and AKI. Further research should examine interventions to shorten AKI-recovery time and its impact on subsequent outcomes.

Mesenchymal stromal cell (MSC)-derived small extracellular vesicles (sEVs) show therapeutic potential in multiple disease models, including kidney injury. Clinical translation of sEVs requires further preclinical and regulatory developments, including elucidation of the biodistribution and mode of action (MoA). Biodistribution can be determined using labelled sEVs in animal models which come with ethical concerns, are time-consuming and expensive, and may not well represent human physiology. We hypothesised that, based on developments in microfluidics and human organoid technology, in vitro multi-organ-on-a-chip (MOC) models allow us to study effects of sEVs in modelled human organs like kidney and liver in a semi-systemic manner. Human kidney- and liver organoids combined by microfluidic channels maintained physiological functions, and a kidney injury model was established using hydrogenperoxide. MSC-sEVs were isolated, and their size, density and potential contamination were analysed. These sEVs stimulated recovery of the renal epithelium after injury. Microscopic analysis shows increased accumulation of PKH67-labelled sEVs not only in injured kidney cells, but also in the unharmed liver organoids, compared to healthy control conditions. In conclusion, this new MOC model recapitulates therapeutic efficacy and biodistribution of MSC-sEVs as observed in animal models. Its human background allows for in-depth analysis of the MoA and identification of potential side effects.