In the planned randomized controlled prospective pilot study, we aim to evaluate ADVOS compared with conventional hemodialysis regarding the elimination of protein-bound toxins in patients with therapy-refractory hepatorenal syndrome.

The study will be performed in a regular non-ICU ward with a large experience in the use of the ADVOS therapy.

Acute on chronic liver failure (ACLF) is a syndrome in patients with liver cirrhosis characterized by acute hepatic decompensation (i.e., jaundice, ascites, hepatic encephalopathy, bacterial infection, or gastrointestinal bleeding) and single or multi-organ failure, resulting in increased mortality. The European Association for the Study of the Liver (EASL) has established the Chronic Liver Failure (CLIF) consortium, which has developed a score for risk stratification and prognosis estimation, the CLIF-C ACLF score. Based on the CANONIC study, the CLIF consortium has developed a simplified CLIF Consortium Organ Failure Score (CLIF-C OFs), which includes liver, kidney, and lung function, hepatic encephalopathy, coagulation, and hemodynamics. Considering two other mortality factors (age and leukocyte count), the CLIF-C ACLF score was defined. The score has a higher predictive value for 28- and 90-day mortality than the Model of End Stage Liver Disease (MELD), MELD-Na, or Child-Turcotte-Pugh score.

Therapeutic options are limited and aim to address specific organ complications. In most cases, due to progressive renal insufficiency as part of hepatorenal syndrome, renal replacement therapy is if indicated. The only potential cure is liver transplantation.

There is some evidence that extracorporeal liver support can help a patient until liver transplantation or restoration of organ function. The Advanced Organ Support (ADVOS) system (ADVITOS GmbH, Munich, Germany) is an albumin-based advanced hemodialysis procedure, which can support the liver. The principles of conventional renal replacement therapy for the elimination of water-soluble substances are combined with the elimination of protein-bound substances by recirculating a dialysate containing 200 ml of human albumin. This procedure is typically used as continuous treatment in an intensive care setting. However, the investigators have already investigated the possibility of ADVOS as an intermittent procedure in patients with ACLF on a regular ward in a retrospective study.

To the best of knowledge of the investigators, there are currently no randomized studies comparing the elimination of protein-bound toxins between ADVOS and hemodialysis. Nevertheless, based on the investigators clinical experience, the investigators hypothesize that treatment with ADVOS may confer advantages over hemodialysis. Therefore, the objective of this study is to assess the effectiveness of ADVOS in comparison to hemodialysis for the treatment of patients with therapy-refractory hepatorenal syndrome.

Inclusion Criteria:

• Capacity of the patient to give consent
• Pre-existing liver disease in the sense of an ACLF with HRS
• Age >18 years
• Patient of the University Medical Center Mainz
• Bilirubin level ≥ 4 mg/dl
• Indication for renal replacement procedure is based on STARRT-AKI criteria (serum potassium ≥ 6 mmol/l in two independent blood samples; serum pH of 7.2 or less or serum bicarbonate of 12 mmol/l or less; respiratory failure secondary to volume excess)

Exclusion Criteria:

• Age < 18 years
• Pregnancy
• Contraindications for ADVOS therapy
• Already started renal replacement therapy
• Contraindication for citrate anticoagulation
• Use of vasopressors and MAD ≤ 50 mmHg.
• Terminal cancer