Improvement of hepatorenal syndrome with extracorporeal albumin dialysis MARS: results of a prospective, randomized, controlled clinical trial

Personal view: current role of artificial liver support devices

Enthusiasm for liver support devices, particularly cell-based biological systems and albumin dialysis, increased over the last decade and there has been considerable clinical activity both within and without the construct of clinical trials. Most data have been generated on patients with acute liver failure or in patients with decompensation of chronic liver disease, often referred to as acute-on-chronic liver failure. In acute liver failure liver, liver support devices are more realistically being used as a 'bridge' to liver transplantation rather than to transplant-free survival. In acute-on-chronic liver failure the clinical objective of attaining clinical stability with treatment appears more achievable. The so-called bioartificial liver device, based on porcine hepatocytes, is the most extensively evaluated biological device. A sizeable clinical trial failed to demonstrate efficacy, but secondary analyses suggest it would be unwise to assume futility had been established with this device. Molecular adsorbent recirculating system leads the way in the non-biological category in terms of the number of patients treated, but data from large clinical trials are not yet available. One of the strongest conclusions of this review is that the amount of high-quality data available on liver support devices dramatically understates the effort and money that have been expended in their assessment. It is very clear that randomized controlled trials are mandatory to establish clinical efficacy, but it is less clear how the ideal trial should be constructed.

Hepatorenal syndrome

Hepatorenal syndrome (HRS) is defined as functional renal failure that develops in patients with advanced liver disease. HRS may be either slowly or rapidly progressive (type I and II HRS, respectively). Untreated HRS carries a high mortality. Liver transplantation is the best available treatment for HRS. However, all patients with HRS are not suitable candidates for transplantation. Moreover, an organ is often not available in a timely manner in those who are candidates for transplantation. Treatment with vasoconstrictors (terlipressin, octreotide, and midodrine) and plasma expansion with albumin is beneficial and serves as a bridge to transplantation in such cases. The vasopressin analog, terlipressin, produces a sustained reversal of HRS in about 57% to 78% of the patients. The benefits of terlipressin are seen mainly in those who are also receiving albumin simultaneously. In those who improve, recurrence of HRS is reported to be relatively uncommon in the short and intermediate term. In the United States, terlipressin is not available, and octreotide and midodrine are often used for the medical management of HRS. Unfortunately, there are only limited uncontrolled data to support the use of these drugs for HRS. In those who respond to octreotide and midodrine, the subsequent placement of a transjugular intrahepatic portasystemic shunt (TIPS) has been shown to produce a sustained improvement in renal function. TIPS alone also improves renal functions in selected patients with HRS. The exact role of TIPS in HRS needs further evaluation, as patients with HRS are particularly at risk for complications such as encephalopathy and liver failure. Molecular adsorbent recirculating system (MARS) is an albumin-based dialysis system that has a promising role in the treatment of HRS and liver failure. MARS is a very expensive form of treatment, and further clinical trials are needed to establish its utility. Development of HRS can be prevented by adding albumin to the antibiotic regimen to treat spontaneous bacterial peritonitis and through pentoxifylline administration to the patients with acute alcoholic hepatitis.

Hepatorenal syndrome

Among the many causes of renal failure in patients who have advanced liver disease, functional renal failure occurring in the absence of parenchymal kidney disease, better known as hepatorenal syndrome (HRS), is the most frequent cause of renal dysfunction in patients who have cirrhosis. This article focuses on the pathogenesis, clinical features, diagnostic approach, and current treatment of HRS in cirrhosis.

Slow continuous ultrafiltration with bound solute dialysis

Bound solute dialysis (BSD), often referred to as "albumin dialysis" (practiced clinically as the molecular adsorbents recirculating system, MARS, or single-pass albumin dialysis, SPAD) or "sorbent dialysis" (practiced clinically as the charcoal-based Biologic-DT), is based upon the thermodynamic principle that the driving force for solute mass transfer across a dialysis membrane is the difference in free solute concentration across the membrane. The clinically relevant practice of slow continuous ultrafiltration (SCUF) for maintenance of patients with liver failure is analyzed in conjunction with BSD. The primary dimensionless operating parameters that describe SCUF-BSD include (1) beta, the dialysate/blood binder concentration ratio; (2) kappa, the dialyzer mass transfer/blood flow rate ratio; (3) alpha, the dialysate/blood flow rate ratio; and, (4) gamma, the ultrafiltration/blood flow rate ratio. Results from mathematical modeling of solute removal during a single pass through a dialyzer and solute removal from a one-compartment model indicate that solute removal is remarkably insensitive to gamma. Solute removal approaches an asymptote (improvement in theoretical clearance over that obtainable with no binder in the dialysate) with increasing beta that is dependent on kappa and independent of alpha. The amount of binder required to approach the asymptote decreases with increasing solute-binder equilibrium constant, i.e., more strongly bound solutes require less binder in the dialysate. The results of experimental observations over a range of blood flow rates, 100 to 180 mL/min, dialysate flow rates, 600 to 2150 mL/h, ultrafiltration rates, 0 to 220 mL/h, and dialysate/blood albumin concentration ratios, beta = 0.01 to 0.04, were independently predicted remarkably well by the one-compartment model (with no adjustable parameters) based on BSD principles.

Life-threatening intoxication with methylene bis(thiocyanate): clinical picture and pitfalls. A case report

Background

Methylene bis(thiocyanate) (MBT) is a microbiocidal agent mainly used in industrial water cooling systems and paper mills as an inhibitor of algae, fungi, and bacteria.

Case presentation

We describe the first case of severe intoxication following inhalation of powder in an industrial worker. Profound cyanosis and respiratory failure caused by severe methemoglobinemia developed within several minutes. Despite immediate admission to the intensive care unit, where mechanical ventilation and hemodialysis for toxin elimination were initiated, multi-organ failure involving liver, kidneys, and lungs developed. While liver failure was leading, the patient was successfully treated with the MARS (molecular adsorbent recirculating system) procedure.

Conclusion

Intoxication with MBT is a potentially life-threatening intoxication causing severe methemoglobinemia and multi-organ failure. Extracorporeal liver albumin dialysis (MARS) appears to be an effective treatment to allow recovery of hepatic function.

Sorbent Suspensions vs. Sorbent Columns for Extracorporeal Detoxification in Hepatic Failure

Hepatic failure is a significant medical problem which has been unsuccessfully treated by hemodialysis. However, similar therapies using recirculated dialysate regenerated by sorbents in place of single-pass dialysate have been beneficial in treating acute-on-chronic liver failure. The advantages of sorbent-based treatments include some selectivity of toxin removal and improved removal of protein-bound toxins. Activated carbon has been extensively used in detoxification systems, but has often had insufficient toxin capacity. Powdered activated carbon, because of its large surface area, can provide greater binding capacity for bilirubin and other toxins than granular carbon commonly used in detoxifying columns. Methods of using powdered carbon in extracorporeal blood treatment devices are reviewed in the present paper, including liver dialysis and a new sorbent suspension reactor (SSR); and the abilities and limitations of the SSR and columns to process protein solutions are discussed.

Cell-Free Artificial Liver Support: Design of Appropriate Clinical Studies

The clinical use of cell-free liver support devices is dependent upon proof of safety and efficacy in clinical trials. The current published data to support their use is limited in both quantity and quality. In most studies, the methodology is such that the effects of these devices are difficult to establish with certainty. Bias might be introduced by the use of uncontrolled studies, and in randomized controlled trials limited size, poorly matched control groups or medical therapy or the use of clinically inappropriate endpoints might be important. Guidelines are now available to provide a framework for the design and execution of such trials, specifically to minimize the systematic errors that are frequently present and that might result in biased estimates of treatment effects. In the present review, the limitations of current studies are discussed and suggestions made as to the design and conduct of future clinical trials.

THIS ARTICLE HAS BEEN RETRACTED: An Australian Experience With the Molecular Adsorbents Recirculating System (MARS)

The molecular adsorbents recirculating system (MARS) is a form of artificial extracorporeal liver support which has the potential to remove substantial quantities of albumin-bound toxins postulated to contribute to the pathogenesis of liver cell damage, hemodynamic instability and multi-organ failure in patients with acute liver failure and acute-on-chronic liver failure (AoCLF). We assessed the efficacy of MARS therapy in a cohort of patients with severe liver damage unresponsive to intensive medical therapy. MARS therapy was instituted late in the clinical course of six patients with severely impaired liver function refractory to intensive medical therapy, including four with AoCLF precipitated by sepsis and two with liver dysfunction due to sepsis in the absence of pre-existing chronic liver disease. Outcome measures included markers of hemodynamic stability, renal function, serum bilirubin and bile acid levels, arterial ammonia levels, the arterial ketone body (acetoacetate/beta-hydroxybutyrate) ratio, hepatic encephalopathy grade and the plasma disappearance rate of indocyanine green. The rates of discharge from the intensive care unit and in-hospital mortality were determined. Our findings suggest that MARS treatment might be associated with some clinical efficacy even in patients with advanced multi-organ dysfunction occurring in the setting of severe liver damage and in whom treatment is instituted late in the clinical course. However, the overall survival rate (1/6; 17%) was poor. More data obtained from larger cohorts of patients enrolled in randomized controlled studies will be required in order to identify categories of liver failure patients who might benefit most from MARS treatment and to ascertain the most appropriate timing of intervention.

Review article: non-biological liver support in liver failure

Liver failure, whether acute or acute-on-chronic, remains an important cause of morbidity and mortality. The lack of liver detoxification, metabolic and regulatory functions of the liver leads to life-threatening complications, such as renal failure, altered immune response, hepatic coma and systemic haemodynamic dysfunction, eventually culminating in multiorgan failure. Current medical therapy involves the management of the precipitating event and treatment of complications until the liver eventually recovers, leaving us with no other treatment options than transplantation if these attempts fail. However, the shortage in cadaveric organs and other transplant-related problems, have prompted the need for alternative methods to provide liver support. As liver failure is often potentially reversible, considerable effort has been invested in the development of liver support systems. Currently, most of the experience is available for non-biological support systems. They represent the focus of this review, which aims to define the goals of liver support, to describe the design of the different existing devices and to analyse the available data to determine their current status in the management of patients with liver failure.

Progress in treatment of massive ascites and hepatorenal syndrome

Massive ascites and hepatorenal syndrome (HRS) are frequent complications of liver cirrhosis. Thus, effective therapy is of great clinical importance. This concise review provides an update of recent advances and new developments. Therapeutic paracentesis can be safely performed even in patients with severe coagulopathy. Selected patients with a refractory or recurrent ascites are good candidates for non-surgical portosystemic shunts (TIPS) and may have a survival benefit and improvement of quality of life. Novel pharmaceutical agents mobilizing free water (aquaretics) are currently under test for the therapeutic potential in patients with ascites.

Prophylaxis of hepatorenal syndrome in patients with spontaneous bacterial peritonitis is recommended and should be considered in patients with alcoholic hepatitis. Liver transplantation is the best therapeutic option with long-term survival benefit for patients with HRS. To bridge the time until transplantation, TIPS or Terlipressin and albumin are good options. Albumin dialysis can not be recommended outside prospective trials.

A molecular functional study on the interactions of drugs with plasma proteins

The binding of drugs to plasma proteins, such as albumin and alpha1-acid glycoprotein (AGP) is a major determinant in the disposition of drugs. A topology analysis of drug binding sites on HSA and AGP was determined using various methods, including spectroscopy, QSAR, photoaffinity labeling and site directed mutagenesis. Recombinant albumin was found to be useful for rapidly identifying drug binding sites. The binding sites on AGP are not completely separated but are partially overlapped, and Trp, Tyr, Lys and His residues in the drug binding pockets play important roles in this process. Drug displacement is somewhat complex, due to the involvement of multiple effects. The reduced binding in uremic patients may be explained by a mechanism that involves a combination of direct displacement by free fatty acids as well as cascade effects of free fatty acids and unbound uremic toxins for significant inhibition in serum binding. Albumin-containing dialysate is useful for the extracorporeal removal of endogenous toxins and in the treatment of drug overdoses. Oxidized albumin is a useful biomarker for the quantitative and qualitative evaluation of oxidative stress. Interestingly, AGP undergoes a structural transition to a unique structure that differs from the native and denatured states, when it interacts with membranes.

Fulminant hepatic failure bridged to liver transplantation with a molecular adsorbent recirculating system: a single-center experience

We herein describe the clinical course of a consecutive series of fulminant hepatic failure patients treated with a molecular adsorbent recirculating system (MARS), a cell-free albumin dialysis technique. From November 2000 to September 2002, seven adult patients ages 22-61 (median, 41), one male (14.2%) and six females (85.7%), affected by fulminant hepatic failure underwent seven courses (one to five sessions each, 6 hr in duration) of extracorporeal support using the MARS technique. Pre- and posttreatment blood glucose, liver function tests, ammonia, arterial lactate, electrolytes, hemodynamic parameters, arterial blood gases, liver histology, Glasgow Coma Scale, and coagulation studies were reviewed. No adverse side effects such as generalized bleeding on noncardiogenic pulmonary edema, often seen during MARS treatment, occurred in the patients included in this study. Six patients (85.7%) are currently alive and well, and one (14.2%) died. Four patients (57%) were successfully bridged (two patients in 1 day and two other patients in 4 days) to liver transplantation, while two (5%) recovered fully without transplantation. All the measured variables stabilized after commencement of the MARS. No differences were noted between the pre- and the post-MARS histology. We conclude that the MARS is a safe, temporary life support mechanism for patients awaiting liver transplantation or recovering from fulminant hepatic failure.

[Artificial liver support systems: update on albumin dialysis (MARS)]

Mortality among patients with liver insufficiency continues to be unacceptably high. The prognosis of patients with acute episodes of chronic liver insufficiency is almost as poor as that of patients with acute liver failure. Therefore, systems that support liver function, either until liver transplantation can be performed or until resolution of the situation before acute injury occurs, are essential. Albumin dialysis is a system of artificial liver support that allows detoxification of albumin-related and hydrosoluble substances, thus maintaining the patient's homeostasis. Current clinical experience of this therapy is still limited, although beneficial effects on clinical, laboratory and hemodynamic parameters have been demonstrated. Multicenter, controlled trials to evaluate the effect of this therapy on survival in distinct diseases are needed.

Therapeutic Apheresis-State of the Art in the Year 2005

Therapeutic apheresis is an extracorporeal blood purification method for the treatment of diseases in which pathological proteins or cells have to be eliminated. Selective plasma processing is more efficient in pathogen removal than unselective plasma exchange and does not require a substitution fluid like albumin. This overview presents the various selective devices for the treatment of plasma (plasmapheresis) and blood cells (leukocyte apheresis). Prospective randomized trials were performed for the treatment of age-related macular degeneration (Rheopheresis), sudden hearing loss (heparin-induced lipoprotein precipitation [HELP]), rheumatoid arthritis (Prosorba), dilative cardiomyopathy (Ig-Therasorb, Immunosorba), acute-on-chronic liver failure (molecular adsorbent recirculating system [MARS]), and ulcerative colitis (Cellsorba). Prospective non-randomized controlled trials were carried out treating hypercholesterolemia (Liposorber) and crossmatch-positive recipients before kidney transplantation (Immunosorba). Uncontrolled studies were done for ABO-incompatibility in living donor kidney transplantation (KT) (Glycosorb), acute humoral rejection after KT (Immunosorba) and acute liver failure (Prometheus). According to the 2002 International Apheresis Registry covering 11428 sessions in 811 patients, 79% of the patients showed an improvement of their condition by apheresis and only a few sessions were fraught with adverse effects (AE). The major AE were blood access difficulties (3.1%) and hypotension (1.6%). In summary, therapeutic apheresis is a safe and effective procedure for the treatment of diseases refractory to drug therapy.

The attributable mortality of acute renal failure in critically ill patients with liver cirrhosis

OBJECTIVE

To determine outcome and mortality risk related to acute renal failure (ARF) in critically ill patients with cirrhosis.

DESIGN AND SETTING

A retrospective cohort analysis and two independent case-control analyses in a medical ICU.

PATIENTS

41 and 32 patients who developed mild and severe ARF, respectively, matched (1:2 ratio) with cirrhotic patients without ARF during their ICU stay.

MEASUREMENTS AND RESULTS

Cirrhotic patients with ARF had higher MELD, APACHE II, and SOFA scores at baseline that those without ARF. They had more respiratory failure and cardiovascular failure during ICU stay, longer stay in ICU, and a greater crude hospital mortality rate (65% vs. 32%). Multivariate survival analysis identified ARF (hazard ratio, HR, 4.1), alcohol abuse or dependency, and severe sepsis or septic shock as independent predictors of death. In case-control studies both mild and severe ARF were independently associated with mortality (HR, 2.6, and 4.2, respectively). Cirrhotic patients with mild ARF patients had a higher risk of death than those without ARF (relative risk, RR, 2.0). Severe ARF was associated with an increase matched risk of death (RR 2.6), higher mortality of 51%, and higher risk-adjusted mortality rate (2.1 vs. 0.9).

CONCLUSIONS

ICU patients with liver cirrhosis still have a high crude mortality. In this specific population ARF is associated with an excess mortality, depending on the severity of renal dysfunction.

Liver support systems: promise and reality

Effective liver support is needed for a variety of indications. A large number of both biological (containing hepatocytes) and non-biological extracorporeal liver support systems have been described in the literature over the last 50 years. Despite this, there is a paucity of good quality randomized control data examining the effectiveness of these therapies in human liver failure. In this review article, we examine the available data, with particular emphasis on the current front runners, the MARS and HepatAssist systems. Other problems associated with the development of these liver support systems are also discussed. Although promising in animal studies, we conclude that the use of these technologies is not supported currently by a sufficient evidence base to recommend them for routine clinical use and that a lack of understanding about the critical functions required of a liver support system is retarding a more rational approach to the design of these systems.

Extracorporal liver support with molecular adsorbents recirculating system in patients with hepatitis B-associated fulminant hepatic failure

Hepatitis B virus (HBV) infection is the most prevalent cause of fulminant hepatic failure (FHF) in the Far East. HBV-associated FHF is characterised by rapidly progressive end organ dysfunction/failure and a very poor prognosis. To investigate how molecular adsorbent recirculating system (MARS) treatment impacts multiple organ system function in HBV-associated FHF. Ten consecutive patients were treated with MARS in a period of 12 months. Clinical, biochemical and haemodynamic parameters were assessed before and after MARS. Various disease severity scoring systems including model for end-stage liver disease, APACHE II, APACHE III, sequential organ failure assessment and organ system failure scores were also assessed. There were significant improvements in hepatic encephalopathy grading (p < 0.001), mean arterial pressure (p < 0.001), plasma renin activity (p = 0.027), bilirubin (p < 0.001), ammonia (p = 0.001) and creatinine levels (p < 0.001). There were also significant improvements in all the scoring systems evaluated. Meanwhile, platelet count was significantly decreased (p < 0.001). One patient was successfully bridged to liver transplantation. Three patients were alive at 3 months of follow-up. MARS can improve multiple organ functions in HBV-associated FHF. On the basis of these findings, randomised controlled studies are indicated and justified.

Modification of continuous venovenous hemodiafiltration with single-pass albumin dialysate allows for removal of serum bilirubin

A 53-year-old woman was admitted to the hospital with ischemic colitis and underwent a subtotal colectomy. She developed acute renal failure, severe hyperbilirubinemia, and intense pruritus resistant to medical treatment. Extracorporeal albumin dialysis using a Molecular Adsorbent Recirculating System (MARS; Gambro Co, Lund, Sweden) has been used to treat liver failure and reduce total serum bilirubin (SB) levels. A trial of extracorporeal albumin dialysis with continuous renal replacement therapy (RRT) was instituted to achieve net removal of SB. A 25% albumin solution was mixed with conventional dialysate to yield a dialysate concentration of 1.85% or 5.0% albumin. The patient underwent 2 continuous RRT sessions using extracorporeal albumin dialysis (1.85% and 5.0% albumin dialysate). Pretreatment and posttreatment SB levels were determined, and total bilirubin concentration (TB) also was measured in each of the collection bags during conventional and albumin dialysis. Pretreatment and posttreatment SB levels were 50.4 mg/dL (862 micromol/L) and 39.0 mg/dL (667 micromol/L) with 1.85% albumin dialysate and 47.1 mg/dL (805 micromol/L) and 39.7 mg/dL (679 micromol/L) with 5.0% albumin dialysate, respectively. The collected dialysate TB level was 0.3 mg/dL (5 micromol/L) during nonalbumin RRT and increased to 1.37 +/- 0.06 mg/dL (23 +/- 1 micromol/L) with 1.85% albumin dialysis. The collected dialysate fluid TB level was 0.3 mg/dL (5 micromol/L) during the nonalbumin RRT and increased to 1.38 +/- 0.15 mg/dL (24 +/- 3 micromol/L) during 5.0% albumin RRT. Single-pass albumin dialysis with continuous RRT cleared SB better than standard continuous RRT. Single-pass albumin dialysis with continuous RRT is feasible and may be a viable alternative in centers that do not have access to MARS therapy. This modality merits additional evaluation for its efficacy in clearing albumin-bound serum toxins.

Outcome from molecular adsorbent recycling system (MARS) liver dialysis following drug-induced liver failure

RATIONALE

Fulminant liver failure from drug ingestion is associated with a high mortality, and the introduction of liver transplantation has improved the mortality significantly if done in a timely fashion. Recently, molecular adsorbent recycling system (MARS) liver dialysis has been introduced as a support for liver failure with varying results. We review our experience with drug-induced liver failure and the impact of MARS liver dialysis on the outcome, in a setting where cadaveric liver transplantation is rarely available.

RESULTS

A total of 13 patients were treated, and 40 sessions of MARS liver dialysis were conducted in the intensive care unit. The majority of cases were because of herbal medicine toxicity. Total bilirubin, conjugated bilirubin, and delta bilirubin were significantly reduced, with no change in unconjugated bilirubin. All patients satisfied the criteria for urgent liver transplantation with an average Model End Stage Liver Disease (MELD) score of 35. Only one patient received a liver transplantation from a live donor (right lobe). Overall mortality was 85%. Median time-to-death from the start of MARS was 8 days.

CONCLUSIONS

MARS liver dialysis in a setting without timely liver transplantation is associated with a poor outcome. It does, however, provide a window of time for consideration of living donors in the setting of limited cadaveric donors.

Experience of MARS Therapy With and Without Transplantation in 101 Patients With Liver Insufficiency

Liver support devices are used to treat life-threatening organ dysfunction until a hepatic graft is available or recovery of the native liver. We used a blood purification system--molecular adsorbent recycling system (MARS)--that is based on removal of both protein-bound and water-soluble substances and toxins. Within 2.5 years we treated 101 patients, who were stratified to three subgroups: acute liver failure (ALF; n = 56), acute decompensation in chronic liver failure (AcOCh; n = 35) and liver graft failure (n = 10). MARS seems to be a promising therapy for ALF, allowing the patient's own liver to recover or to gain enough time to find a liver graft. The most promising results, namely the highest number of livers to recovery were observed among acute patients with liver failure due to a toxic etiology. However, we did not discover much benefit of MARS for patients with AcOCh without liver transplantation.

Reviews: The Current State of Nonuremic Applications for Extracorporeal Blood Purification

Despite the commonly accepted indications for hemodialysis and extracorporeal depuritive techniques, some clinicians have come to rely on blood purification for clinical states where the targeted substance for removal differs from uremic waste products. Over the last decade, a number of studies have emerged to help define the application of extracorporeal blood purification (ECBP) to these "nonuremic" indications. This review describes the application of extracorporeal blood purification in clinical states including sepsis, rhabdomyolysis, congestive heart failure, hepatic failure, tumor lysis syndrome, adult respiratory distress syndrome, intravenous contrast exposure, and lactic acidosis. Additional comments are provided to review existing literature on thermoregulation and osmoregulation, including acute brain injury.

The effect of albumin dialysis on cytokine levels in acute liver failure and need for liver transplantation

In acute liver failure (ALF), detoxification capacity of liver cells is reduced and a variety of cytokines, immune modulators, and toxic substances are accumulating. Multiple organ failure in ALF has been associated with increased blood cytokine levels. We have used a blood purification system, molecular adsorbent recirculating system (MARS), which is based on removal of both protein bound and water-soluble substances and toxins in liver failure. In this study, we measured the effect of MARS therapy on plasma cytokine levels in 49 patients with ALF. Interleukin 6 (IL-6), IL-8, IL-10 and tumor necrosis factor (TNF)alfa were determined immediately before and after the first MARS therapy and after the last session using enzyme-linked immunosorbent assays. The overall survival of these ALF patients was 82% at 6 months; the native liver recovered in 26 cases, and 14 were successfully transplanted. All three interleukins were increased before the MARS treatment but only anti-inflammatory IL-10 was reduced significantly during therapy, which in this setting could be interpreted as a positive effect. We were not able to show constant decreases in proinflammatory cytokines, but only transient effects on IL-8 and IL-6. Surprisingly TNFalfa level was normal and did not change during therapy. In theory, MARS albumin dialysis may remove toxic substances from the blood circulation and thereby improve the possibilities of the liver to recover; however, of the measured cytokines only IL-10 decreased significantly.

The effect of molecular adsorbent recirculating system on pathophysiological parameters in patients with acute liver failure

OBJECTIVE

To investigate the effect of the molecular adsorbent recirculating system (MARS) on physiological variables in patients with acute liver failure.

DESIGN

A prospective, observational study of MARS in addition to standard medical therapy in the management of patients presenting with acute liver failure.

SETTING

A regional liver transplant centre.

PATIENTS

Ten consecutive patients admitted with acute liver failure with a grade III or IV hepatic encephalopathy.

INTERVENTIONS

MARS therapy for 8 h on 2 consecutive days. Standard monitoring included the use of a pulmonary artery catheter and an intracranial pressure monitor.

MEASUREMENTS AND RESULTS

During the first MARS treatment there was a significant increase in systemic vascular resistance index (SVRI) from 1114+/-196 to 1432+/-245 dyne s(-1) cm(-5) m(-2) with a reduction in cardiac index from 5.5+/-0.6 to 4.2+/-0.4 l min(-1) m(-2). The changes were maintained between the start of the first and second sessions but not to the end of second. Significant clearance of urea and creatinine was observed. Intracranial pressure did not change during the treatments. Overall mortality was 70%.

CONCLUSIONS

MARS therapy was well tolerated, with significant increases in vascular tone during the first session. This increase was not sustained over the duration of the study with a return to baseline values by the end of the second session. Based on our experience we cannot recommend the routine use of MARS therapy in acute liver failure outside of a clinical trial.

Technology insight: liver support systems

Emergency orthotopic liver transplantation (OLT) is currently the only standard treatment for fulminant hepatic failure (FHF). The waiting time for transplantation can exceed a week-using a liver assist device to bridge patients with FHF to OLT might therefore decrease the mortality rate. Several liver support systems have been described, but no system has gained FDA approval or widespread clinical acceptance. Although the results of many experimental and clinical trials are encouraging, the field is still in its initial stages. Using nonbiologic liver support is based on the assumption that several toxins that cause hepatic coma can be removed from the circulation by blood or plasma sorption methods. As these toxins could be involved in many FHF complications recovery without the need for transplantation is the ultimate aim. Biologic liver support uses xenogeneic livers or hepatocytes to support the failed human liver, exploiting biological cell functions, namely detoxification, metabolism, and biosynthesis. The classical nonbiologic dialysis methods could decrease mortality in patients with acute-on-chronic liver failure, but definitive conclusions are impossible to draw because of the small number of patients studied and inadequate follow-up. Larger studies performed in specialty centers should provide conclusive data about the role of the bioartificial liver support system as a possible universal bridge to OLT. This article presents an overview of published experience with liver support systems since the 1960s.

In vivo quantification of liver dialysis: comparison of albumin dialysis and fractionated plasma separation

BACKGROUND/AIMS

Artificial liver support represents a potentially useful option for the treatment of severe liver failure. A sufficient 'dose' might be crucial for such treatments to provide a survival benefit. The aim of this study was to compare in vivo efficiency and resulting delivered treatment dose of two commercially available devices that use different therapeutic principles: albumin dialysis (AD, MARS) and fractionated plasma separation (FPS, Prometheus).

METHODS

Eight patients with acute-on-chronic liver failure were treated alternately with AD and FPS. Thirty-two treatments at identical blood and dialysate flow rates were evaluated. Clearance and reduction ratio (a measure of delivered treatment dose) were compared for bilirubin subfractions, ammonia and urea.

RESULTS

FPS achieved significantly higher clearance for all measured protein-bound and water-soluble markers. This resulted in significantly higher reduction ratios for FPS compared to AD. Unconjugated bilirubin, a marker for strongly albumin-bound toxins, was influenced only by FPS.

CONCLUSIONS

FPS provided a higher delivered treatment dose than a matching treatment with AD. Reduction ratios of bilirubin and urea should be reported in clinical studies on liver dialysis, since delivered dose is likely to be linked to the clinical effectiveness of extracorporeal liver support therapies.

[MARS (Molecular Adsorbents Recirculating System). New technique of extracorporeal depuration in liver failure]

MARS (Molecular Adsorbent Recirculating System) is a new technique as a system of liver detoxification in patients with severe acute or acute on chronic hepatic failure. Also, it has shown its usefulness in the control of resistant pruritus in the primary biliary cirrhosis. Due to the fact that this technique is often delivered in Intensive Care Units (ICUs), we have reviewed the literature 1999 until now to describe this technique, its benefits and its mains complications. The technique was developed in Germany, where in 1999 was first used in clinical practice. It was used for the first time in Spain in 2000 and in the Clínica Universitaria of Navarra in July of 2001. Despite the short clinical experience using MARS its obvious beneficial effects such as decrease of hepatic toxins and the improvement of encephalopathy and hemodynamic situation, makes it a very useful technique in these patients. MARS has been shown to be a safe procedure, well tolerated by patients and accessible to the use by specialised nurses. Despite the encouraging clinical results, its used is still limited. Moreover its high cost precludes it widespread use and requires further studies.

Detoxifying capacity and kinetics of prometheus--a new extracorporeal system for the treatment of liver failure

BACKGROUND/AIMS

Extracorporeal liver support therapies have been used for several decades as a bridging therapy prior to liver transplantation or as an addendum to standard medical therapy. The Prometheus system represents a cell-free, extracorporeal, liver assist method for the removal of both albumin-bound and water-soluble endogenous toxins. The aim of the present study was to evaluate the removal capacity and selectivity of the different inbuilt dialyzers and adsorption columns during a single 6-hour treatment.

METHODS

Nine patients with acute on chronic liver failure were included (6 females, age 49+/- 4 years). Levels of endogenous toxins (urea nitrogen [UN, mg/dl], creatinine [Cr, mg/dl], total bilirubin [tB, mg/dl], and bile acids [BA, mumol/l]) and albumin [Alb, g/l] were monitored in blood sampled at different sites (arterial line, venous line and between the absorbers and the high-flux dialyzer) and at various time points (time 0, 30, 60, 120, 240, and 360 min).

RESULTS

A significant decrease of the serum level of all toxins was observed (UN 108.7+/- 23.2 vs. 38.1+/- 14.9, Cr 2.4+/- 0.7 vs. 1.2+/- 0.3, tB 31.1+/- 4.1 vs. 17.0+/- 1.6, BA 155.7+/- 32.5 vs. 66.0+/- 15.4; mean+/- SEM, time 0 vs. time 360, signed rank rest, all p< 0.005). The reduction rate of UN, Cr, tB and BA amounted to 68.1+/- 5.1, 45.9+/- 6.2, 41.2+/- 5.1, and 58.2+/- 5.0%, respectively. Blood clearances [Cl, ml/min] of all, but especially of the protein-bound toxins declined over time (Cl UN 171.5+/- 4.3 vs. 142.9+/- 16.8; Cl Cr 135.7+/- 10.0 vs. 111.8+/- 9.1; Cl tB 29.3+/- 5.1 vs. 13.7+/- 3.7; Cl BA 84.9+/- 4.8 vs. 45.1+/- 13.3; time 30 vs. time 360; linear mixed models, all p< 0.005). Serum albumin levels decreased by 2.9+/- 0.9 g/l (signed rank test, p=0.055). Not unexpectedly, tB was almost uniquely cleared by the adsorbers (UN 0.2+/-1.1, Cr 6.9+/- 5.7, tB 92.3+/- 4.2, BA 62.9+/- 3.9% of total Cl).

CONCLUSION

Both albumin-bound and water-soluble toxins are adequately removed by the Prometheus system. Our data suggest that the rate and efficacy of removal of albumin-bound toxins is related to both the strength of the albumin binding and the saturation of the adsorption columns. Limited losses of albumin occur during treatment with the Prometheus system.

Catholic university experience with molecular adsorbent recycling system in patients with severe liver failure

BACKGROUND AND AIM

Molecular adsorbent recycling system (MARS) treatment is able to remove both hydrosoluble and small- and medium-sized lipophilic toxins. MARS plays an important role in modifying liver failure complications, such as hepatorenal syndrome and hepatic encephalopathy. We sought to evaluate the clinical efficacy and safety of a MARS device in a consecutive series of hepatic failure patients.

MATERIALS

Twenty patients with acute liver failure, transplantation failure, or acute on chronic liver failure fulfilled the inclusion criteria of total bilirubin > or =10 mg/dL and at least one of the following: hepatic encephalopathy (HE) > or =II grade, hepatorenal syndrome (HRS) for chronic patients or total bilirubin > or =5 mg/dL and HE > or =I grade for acute patients.

RESULTS

MARS was able to reduce cholestatic parameters and improve neurologic status and renal function parameters in all treated patients. We also observed an improvement in the 3-month survival rate compared to the expected outcome in patients with MELD scores between 20 and 29, as well as 30 and 39.

CONCLUSIONS

Based on these results, we confirm the safety and clinical efficacy of MARS treatment, with the best results in patients with MELD score of 20 to 29. Further studies are necessary to confirm whether this treatment is able to modify patient outcomes and prognosis.

Le syndrome hépatorénal chez le patient cirrhotique

Hepatorenal syndrome is a particular form of functional renal failure which may develop in patients with liver cirrhosis. On a clinical standpoint, precise diagnostic criteria have been established to clearly define this entity, whereas recent advances in the understanding of the biology of vasoactive mediators and the physiology of microcirculation have allowed to better anticipate its pathophysiological mechanisms. During the course of cirrhosis, sinusoidal portal hypertension leads to splanchnic and systemic vasodilation, responsible for a reduction of effective arterial blood volume. As a result, a state of intense renal vasoconstriction develops, leading to renal failure in the absence of any organic renal disease. At this stage, liver transplantation is the only definitive therapy able to reverse renal dysfunction. In recent years, innovative therapies have shown promise to prolong survival in patients with hepatorenal syndrome, including the administration of analogs of vasopressin (mainly terlipressin), the insertion of transjugular intrahepatic portosystemic shunts and the use of novel techniques of dialysis. On a preventive viewpoint, several simple measures have been shown to reduce the risk of hepatorenal syndrome in cirrhotic patients, including the appropriate use of diuretics, the avoidance of nephrotoxic drugs, the prophylaxis of spontaneous bacterial peritonitis and optimal fluid management in patients undergoing large volume paracentesis.

Albumin dialysis reduces portal pressure acutely in patients with severe alcoholic hepatitis

BACKGROUND/AIMS

In patients with alcoholic hepatitis (AH), inflammation contributes to the severity of portal hypertension. This study evaluates the acute effects of albumin dialysis, using the Molecular Adsorbents Recirculating System (MARS), on portal pressure in AH.

METHODS

Eleven patients with AH and portal hypertension were treated with MARS (n=8) or haemofiltration (n=3). All patients had associated organ failure manifested by hepatic encephalopathy (Grade 2 or more) or renal failure. Hepatic venous pressure gradient (HVPG) was measured before, during and after the treatment session.

RESULTS

A rapid significant reduction of HVPG was observed by 6 h (falling by > or =20% in 7/8 patients, reaching 12 mmHg in 6/8), which was sustained up to 18 h after stopping dialysis. Similar rapid sustained improvements of systemic haemodynamics were also observed. No changes occurred in three patients receiving haemofiltration alone.

CONCLUSIONS

Albumin dialysis produces clinically significant, acute reduction in portal pressure but the mechanism by which this effect is achieved is not clear. Our results suggest that MARS may be a useful adjunct in management of portal hypertension, particularly in patients with severe AH with associated organ failure.

The Prometheus device for extracorporeal support of combined liver and renal failure

BACKGROUND/AIMS

Prometheus is a newly developed extracorporeal liver support system that combines removal of albumin-bound substances (adsorption on resin adsorbers) and water-soluble substances (diffusion during high-flux hemodialysis). Therefore, it is a promising treatment option for patients with hepatorenal syndrome (HRS).

METHODS

We studied 10 patients with HRS in a prospective clinical study. All patients underwent 2 consecutive Prometheus treatments. A variety of clinical and biochemical parameters were assessed.

RESULTS

Prometheus treatment was uncomplicated and safe. A statistically significant improvement of serum creatinine and urea concentrations as well as blood pH was observed after Prometheus treatment. Furthermore, liver detoxification was supported by a significant decrease of serum levels of conjugated bilirubin, bile acids and ammonia.

CONCLUSIONS

Prometheus is a safe treatment for patients with HRS. Both, albumin-bound and water-soluble substances were effectively removed. Controlled studies will evaluate the effect of this new treatment option on survival in patients with HRS.

Pathophysiological basis of pharmacotherapy in the hepatorenal syndrome

Hepatorenal syndrome (HRS) is a functional and reversible impairment of renal function in patients with severe cirrhosis. Major pathophysiological elements include liver dysfunction, a circulatory derangement with central hypovolaemia and neurohumoral activation of potent vasoactive systems leading to a pronounced renal vasoconstriction. The prognosis of patients with HRS is poor but recent research has spread new enthusiasm for treatment. Efforts at treatment should seek to improve liver function, to ameliorate arterial hypotension and central hypovolaemia, and to reduce renal vasoconstriction. Therefore a combined approach should be applied with reduction of portal pressure with e.g. ss-adrenergic blockers and transjugular intrahepatic portosystemic shunt (TIPS), with amelioration of arterial hypotension and central hypovolaemia with vasoconstrictors such as terlipressin and plasma expanders. New experimental treatments with endothelin- and adenosine antagonists and long-acting vasoconstrictors may have a future role in the management of HRS.

Review article: current management of renal dysfunction in the cirrhotic patient

The United Network for Organ Sharing database revealed that over the last 4-5 years, an average of 1800 patients were removed from the cadaveric waiting list annually because of patients' death and an additional 400-500 were removed from the list because of the severity of their illnesses. The pre-transplant evaluation process, therefore, requires careful and continued assessment of the patient's pulmonary, cardiac and renal function among others. This article describes a systematic approach to the evaluation and management of renal dysfunction complicating the course of advanced liver disease, the pathogenic mechanisms and current recommendations for the treatment of hepatorenal syndrome, and the indications for combined liver-kidney transplantation.

The clinical course of patients with type 1 hepatorenal syndrome maintained on hemodialysis

GOAL

Report the natural coarse of hepatorenal syndrome in 4 patients who were maintained on chronic hemodialysis.

BACKGROUND

The diagnosis of hepatorenal syndrome carries a grave prognosis with a mortality rate >90% and a median survival time of <2 weeks without orthotopic liver transplantation.

STUDY

We report the clinical course of 4 patients with hepatorenal syndrome who underwent long-term (greater than 3 weeks) hemodialysis in an attempt to bridge them to orthotopic liver transplantation. The etiologies of cirrhosis were: chronic hepatitis C infection (n = 2), alcoholic liver disease (n = 1), and primary sclerosing cholangitis (n = 1).

RESULTS

Mean survival time on hemodialysis was 236 days (range: 31 to 460 days). All patients survived their initial hospitalization and were discharged from the hospital. However, only one patient received orthotopic liver transplantation. Mean number of hospital admissions was 11 (range: 4 to 18) while receiving hemodialysis at an average rate of 2.2 (range: 1.1 to 5) admissions/patient month. Mean number of days spent in hospital while on hemodialysis support was 85 days (range: 15 to 199 days) at an average rate of 11.2 (range: 8.3 to 15) hospital days/patient month. An average of 33% (range: 26% to 48%) of the days of the prolonged survival on hemodialysis was spent in hospital.

CONCLUSION

Although our 4 patients with hepatorenal syndrome demonstrated long-term survival with hemodialysis, their prolonged survival was at the cost of a very heavy burden of morbidity and in-patient stay. The advisability of maintenance hemodialysis in patients with hepatorenal syndrome should be judged on an individual basis.

Liver failure

PURPOSE OF REVIEW

Liver failure is a rare but life-threatening condition affecting a multitude of other organ systems, most notably the brain and kidneys, following severe hepatocellular injury. Liver failure may develop in the absence ('acute') or presence ('acute-on-chronic') of liver disease with substantial differences in pathophysiology and therapeutic options. Within the last 12 months substantial progress has been made in identifying patients who will potentially benefit from extracorporeal support of their failing liver.

RECENT FINDINGS

In addition to traditional 'static' laboratory tests to assess liver function, the significance of 'dynamic' tests, such as indocyanine green clearance, has been better defined, and these tests are becoming more easily available. Transplantation remains the treatment of choice for fulminant, acute and subacute liver failure with predicted unfavorable outcome according to King's College or Clichy criteria, most notably in the absence of pre-existing liver disease, and should be performed before extrahepatic complications emerge. Encouraging results have been obtained with the use of support systems in patients with acute and acute-on-chronic liver failure in relatively small patient collectives, making well-conducted randomized trials a necessity to define their role in this high-risk population. Current (pre)clinical data suggest that programmed cell death is an important mechanism for the pathogenesis of acute and acute-on-chronic liver failure and, thus, antiapoptotic strategies are promising pharmacologically.

SUMMARY

Although mortality remains high, substantial progress has been made in 2004 regarding the understanding of pathophysiology, and the monitoring and support of the patient presenting with a failing liver.

Hepatorenal syndrome

Hepatorenal syndrome (HRS) is a major complication of patients with cirrhosis, with the annual incidence in patients with ascites being approximately 8% []. This syndrome develops in the latest phase of the disease and there is now evidence that it is an important determinant of patient survival. Many aspects of HRS are, however, still poorly understood. There are two types of HRS: type 1 or progressive HRS which is associated with a very poor prognosis (median survival rate lower than 2 weeks), and type 2 HRS which is characterized by a steady impairment in circulatory and renal function. The pathogenesis of HRS is a deterioration in effective arterial blood volume due to splanchnic arterial vasodilation and a reduction in venous return and cardiac output. It is therefore not surprising that the syndrome can be reversed by the simultaneous intravenous administration of albumin and arterial vasoconstrictors. Intrarenal mechanisms are also important and require prolonged improvement in circulatory function to be deactivated. Long-term administration of intravenous albumin and vasoconstrictors or the correction of portal hypertension with a transjugular intrahepatic portacaval shunt are effective in the treatment of HRS. They also appear to improve survival and may serve as a bridge to liver transplantation, which is the treatment of choice in these patients.

Hepatorenal syndrome: a dreaded complication of end-stage liver disease

Hepatorenal syndrome is the dreaded complication of end-stage liver disease characterized by functional renal failure due to renal vasoconstriction in the absence of underlying kidney pathology. The pathogenesis of hepatorenal syndrome is the result of an extreme underfilling of the arterial circulation secondary to an arterial vasodilation located in the splanchnic circulation. This underfilling triggers a compensatory response with activation of vasoconstrictor systems leading to intense renal vasoconstriction. The diagnosis is based on established diagnostic criteria aimed at excluding nonfunctional causes of renal failure. The prognosis of patients with hepatorenal syndrome is extremely poor especially in those who have a rapidly progressive course. Liver transplantation is the best option in suitable candidates, but it is not always applicable due to the short survival expectancy and donor shortage. Pharmacological therapies based on the use of vasoconstrictor drugs (terlipressin, midodrine, octreotide, or noradrenline) are the most promising in the aim of successfully offering a bridge to liver transplantation. Other treatments such as transjugular intrahepatic portosystemic shunts and albumin dialysis are effective but experience is very limited. Although there is limited information on the prevention of hepatorenal syndrome, intravenous albumin infusion in patients with spontaneous bacterial peritonitis and with oral pentoxifylline in patients with acute alcoholic hepatitis seems to effectively prevent hepatorenal syndrome in these two settings.

Emerging indications for albumin dialysis

The accumulation of albumin-bound toxins in liver failure is believed to be responsible for the development of associated end-organ dysfunctions (kidney, circulation, brain). Albumin dialysis utilizes the scavenging functions of albumin for the removal of toxins. The Molecular Adsorbents Recirculating System (MARS) is one such extracorporeal liver support device where blood is dialyzed across an albumin-impregnated membrane against 20% albumin. Charcoal and anion exchange resin columns in the circuit cleanse and regenerate the albumin dialysate. Clinical studies in the last decade have demonstrated proven reduction in hyperbilirubinemia, along with an improvement in encephalopathy in liver failure patients, as well as apparent improvement in survival. Some studies have also reported improvement of systemic hemodynamics and renal function in these patients. Amelioration of intractable pruritus and treatment of toxicities with albumin-bound substances are some of the newer indications emerging. However, the specific underlying pathophysiological mechanisms are still not clear. Two other systems based on the removal of albumin-bound toxins, the Prometheus (using the principle of fractionated plasma separation and adsorption [FPSA]), and the single pass albumin dialysis (SPAD) are also currently under development but available clinical data are limited.

Anesthesia for liver transplant surgery

Liver transplantation offers patients with liver disease an optimal chance for long-term survival. Current indications, preoperative assessment, patient selection, intraoperative anesthetic management and outcomes are described. The management of special situations, including retransplantation, pediatric transplantation, and fulminant hepatic failure are also reviewed. The success of liver transplantation has led to increased demand. This demand, coupled with a nonexpanding supply of deceased donor organs, has resulted in a shortage of grafts and prolonged waiting times. Novel solutions using segmental liver grafts from living donors, and the challenges associated with this approach, are discussed.

Value of albumin dialysis therapy in severe liver insufficiency

A blood purification system, molecular adsorbents re-circulating system (MARS), is based on the removal of both protein-bound and water-soluble substances and toxins in the liver. We treated a total of 88 patients within 2 years. Of these patients, 45 had acute liver failure (ALF), 31 had acute decompensation of chronic liver disease, eight had graft failure and four had miscellaneous conditions. Of the patients with ALF, 80% survived; in 23 patients their own liver recovered and 13 patients underwent successful transplantation. Only 23% of patients with acute-on-chronic liver failure survived. Most of them were not considered for transplantation due to their having liver failure from alcoholism and from not abstaining from drinking. MARS is a promising therapy for ALF, allowing the patient's own liver to recover or allowing enough time to find a liver graft. Best results were achieved in patients who had been intoxicated with a lethal dose of toxin. On the other hand, we did not observe much benefit in patients with severe acute-on-chronic liver failure (AcoChr) who did not undergo liver transplantation.