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

Evaluating the Effect of Artificial Liver Support on Acute-on-Chronic Liver Failure Using the Quantitative Difference Algorithm: Retrospective Study

BACKGROUND

Liver failure, including acute-on-chronic liver failure (ACLF), occurs mainly in young adults and is associated with high mortality and resource costs. The prognosis evaluation is a crucial part of the ACLF treatment process and should run through the entire diagnosis process. As a recently proposed novel algorithm, the quantitative difference (QD) algorithm holds promise for enhancing the prognosis evaluation of ACLF.

OBJECTIVE

This study aims to examine whether the QD algorithm exhibits comparable or superior performance compared to the Model for End-Stage Liver Disease (MELD) in the context of prognosis evaluation.

METHODS

A total of 27 patients with ACLF were categorized into 2 groups based on their treatment preferences: the conventional treatment (n=12) and the double plasma molecular absorption system (DPMAS) with conventional treatment (n=15) groups. The prognosis evaluation was performed by the MELD and QD scoring systems.

RESULTS

A significant reduction was observed in alanine aminotransferase (P=.02), aspartate aminotransferase (P<.001), and conjugated bilirubin (P=.002), both in P values and QD value (Lτ>1.69). A significant decrease in hemoglobin (P=.01), red blood cell count (P=.01), and total bilirubin (P=.02) was observed in the DPMAS group, but this decrease was not observed in QD (Lτ≤1.69). Furthermore, there was a significant association between MELD and QD values (P<.001). Significant differences were observed between groups based on patients' treatment outcomes. Additionally, the QD algorithm can also demonstrate improvements in patient fatigue. DPMAS can reduce alanine aminotransferase, aspartate aminotransferase, and unconjugated bilirubin.

CONCLUSIONS

As a dynamic algorithm, the QD scoring system can evaluate the therapeutic effects in patients with ACLF, similar to MELD. Nevertheless, the QD scoring system surpasses the MELD by incorporating a broader range of indicators and considering patient variability.

Tailoring the Colloidal Stability, Magnetic Separability, and Cytocompatibility of High-Capacity Magnetic Anion Exchangers

Extracorporeal blood purification has been applied to artificially support kidney or liver function. However, convection and diffusion based blood purification systems have limited removal rates for high molecular weight and hydrophobic molecules. This limitation is due to the finite volume of infusion and limited membrane permeability, respectively. Adsorption provides an attractive alternative for the removal of higher molecular weight compounds. The use of adsorption resins containing ion exchanging groups to capture specific molecules has become well-established. Instead of stationary adsorption resins, however, ion exchanging polymers may be immobilized on magnetic particles and serve as freely diffusing, mobile, high capacity solid phase of ion exchange chromatography. While small beads with high surface area are attractive in terms of mass transfer and binding, unifying high capturing capacity with rapid and quantitative bead recovery remains an issue. Therefore, most of the current magnetic ion exchangers are based on micron-sized beads or require long times to separate. In addition to unfavorable magnetic recovery rates, the usually poor cytocompatibility limits their applicability in biomedicine. Here, we report on the synthesis and performance of polycationic polymer coated magnetic nanoflowers (MNF) for highly efficacious anion capturing. We demonstrate accurate control over the polymer content and composition on the beads and show its direct influence on colloidal stability, capturing capacity and magnetic separability. We present the removal of clinically relevant targets by capturing bilirubin with capacities 2-fold higher than previous work as well as quantitative heparin removal. Additionally, we illustrate how copolymerization of poly(2-dimethylaminoethyl methacrylate) (PDMAEMA) with poly(ethylene glycol) methyl ether methacrylate (PEGMEMA) leads to improved cytocompatibility of the polymer-coated MNF capturing agents while retaining high capturing capacities. Taken together, we present a nanoparticle/polymer material, which upon future in vivo validation, unifies high binding capacities and magnetic separability for rapid toxin capturing and hence fulfills key requirements of clinical utility.

Hybrid Extracorporeal Therapies as a Bridge to Pediatric Liver Transplantation

OBJECTIVES

Standard intensive care treatment is inadequate to keep children with liver failure alive without catastrophic complications to ensure successful transplant, as accumulation of endogenous protein-bound toxins often lead to hepatic encephalopathy, hepatorenal syndrome, cardiovascular instability, and multiple organ failure. Given paucity of proven treatment modalities for liver failure, blood purification using different extracorporeal treatments as a bridge to transplantation is used, but studies evaluating the safety and efficacy of combination of these therapies, especially in pediatric liver failure, are lacking. We describe our experience at a major tertiary children's hospital, where a unique hybrid extracorporeal treatment protocol has been instituted and followed for acute liver failure or acute-on-chronic liver failure as a bridge to transplantation. This protocol combines high-flux continuous renal replacement therapy for hyperammonemia, therapeutic plasma exchange for coagulopathy, and albumin-assisted dialysis (molecular adsorbent recirculating system) for hepatic encephalopathy.

DESIGN

Retrospective observational study.

SETTING

Freestanding tertiary children's hospital and liver transplant referral center.

PATIENTS

All patients with acute liver failure/acute-on-chronic liver failure receiving hybrid extracorporeal therapy over 24 months.

INTERVENTION

Hybdrid extracorporeal therapy.

MEASUREMENTS AND MAIN RESULTS

Fifteen children (age 3 yr [0.7-9 yr]; 73% male) with acute liver failure/acute-on-chronic liver failure who were either listed or actively considered for listing and met our protocol criteria were treated with hybrid extracorporeal therapy; 93% were ventilated, and 80% were on vasoactive support. Of these, two patients recovered spontaneously, four died prior to transplant, and nine were successfully transplanted; 90-day survival post orthotopic liver transplant was 100%. Overall survival to hospital discharge was 73%.

CONCLUSIONS

Hybrid extracorporeal therapies can be effectively implemented in pediatric liver failure as a bridge to transplantation. Overall complexity and heavy resource utilization need to be carefully considered in instituting these therapies in suitable candidates.

A New Application for Albumin Dialysis in Extracorporeal Organ Support: Characterization of a Putative Interaction Between Human Albumin and Proinflammatory Cytokines IL-6 and TNFα

Albumin dialysis in extracorporeal organ support is often performed in the treatment of liver failure as it facilitates the removal of toxic components from the blood. Here, we describe a possible effect of albumin dialysis on proinflammatory cytokine levels in vitro. Initially, albumin samples were incubated with different amounts of cytokines and analyzed by enzyme-linked immunosorbent assay (ELISA). Analysis of interleukin 6 (IL-6) and tumor necrosis factor alpha (TNFα) levels indicated that increased concentrations of albumin reduce the measureable amount of the respective cytokines. This led to the hypothesis that the used proinflammatory cytokines may interact with albumin. Size exclusion chromatography of albumin spiked with cytokines was carried out using high-performance liquid chromatography analysis. The corresponding fractions were evaluated by immunoblotting. We detected albumin and cytokines in the same fractions indicating an interaction of the small-sized cytokines IL-6 and TNFα with the larger-sized albumin. Finally, a two-compartment albumin dialysis in vitro model was used to analyze the effect of albumin on proinflammatory cytokines in the recirculation circuit during 6-h treatment. These in vitro albumin dialysis experiments indicated a significant decrease of IL-6, but not of TNFα, when albumin was added to the dialysate solution. Taken together, we were able to show a putative in vitro interaction of human albumin with the proinflammatory cytokine IL-6, but with less evidence for TNFα, and demonstrated an additional application for albumin dialysis in liver support therapy where IL-6 removal might be indicated.

High-volume hemofiltration in children with acute liver failure*

OBJECTIVES

High-volume hemofiltration has shown beneficial effects in severe sepsis and multiple organ failure, improving hemodynamics and fluid balance. Recent studies suggest that acute liver failure shares many pathophysiologic similarities with sepsis. Therefore, we assessed the systemic effects of high-volume hemofiltration in children with acute liver failure.

DESIGN

Retrospective observational cohort study.

PATIENTS

Twenty-two children.

SETTING

Forty-two-bed multidisciplinary pediatric and neonatal ICUs in a tertiary university hospital.

INTERVENTION

We evaluated high-volume hemofiltration therapy as part of standard management of 22 children admitted in our unit for acute liver failure. Fifteen patients had fulminant hepatic failure, three had acute-on-chronic liver disease, and four had primary nonfunction. High-volume hemofiltration was initiated in patients requiring emergency liver transplantation and when hepatic encephalopathy grade higher than 2 and/or hemodynamic instability requiring vasopressors occurred. High-volume hemofiltration was defined by a flow of ultrafiltrate of more than 80 mL/kg/hr. Clinical and biological variables were assessed before and 24 and 48 hours after initiation of high-volume hemofiltration therapy.

MEASUREMENTS AND MAIN RESULTS

High-volume hemofiltration was initiated with a median grade III of hepatic encephalopathy. The median flow of ultrafiltrate was 119 mL/kg/hr (range, 80-384). After 24 hours of high-volume hemofiltration treatment, we observed an increase in mean arterial pressure (p = 0.0002) and a decrease in serum creatinine (p = 0.0002). In half of the patients, the encephalopathy grade decreased. After 48 hours of treatment, mean arterial pressure (p = 0.0005), grade of hepatic encephalopathy (p = 0.04), and serum creatinine (p = 0.0002) improved. Overall mortality was 45.4% (n = 10). Emergency liver transplantation was performed in eight children. Five patients spontaneously recovered liver function.

CONCLUSIONS

High-volume hemofiltration therapy significantly improves hemodynamic stability and neurological status in children with acute liver failure awaiting for emergency liver transplantation.

Reduction of elevated cytokine levels in acute/acute-on-chronic liver failure using super-large pore albumin dialysis treatment: an in vitro study

The removal of small water soluble toxins and albumin-bound toxins in acute liver failure patients (ALF) or acute-on-chronic liver failure (AocLF) patients has been established using extracorporeal liver support devices (e.g. Molecular Adsorbents Recirculating System; MARS). However, reduction of elevated cytokines in ALF/AocLF using MARS is still not efficient enough to lower patients' serum cytokine levels. New membranes with larger pores or higher cut-offs should be considered in extracorporeal liver support devices based on albumin dialysis in order to address these problems, as the introduction of super-large pore membranes could counterbalance high production rates of cytokines and further improve detoxification in vivo. Using an established in vitro two compartment albumin dialysis model, three novel membranes of different pore sizes were compared with the MARS Flux membrane for cytokine removal and detoxification qualities in vitro. Comparing the membranes, no improvement in the removal of water soluble toxins was found. Albumin-bound toxins were removed more efficiently using novel large (Emic2) to super-large pore sized membranes (S20; HCO Gambro). Clearance of cytokines IL-6 and tumor necrosis factor-α was drastically improved using super-large pore membranes. The Emic2 membrane predominantly removed IL-6. In vitro data suggest that the usage of larger pore sized membranes in albumin dialysis can efficiently reduce elevated cytokine levels and liver failure toxins. Using large to super-large pore membranes might exert effects on patients' serum cytokine levels. Combined with increased detoxification this could lead to higher survival in ALF/AocLF. Promising membranes for clinical evaluation have been identified.

Liver support systems--a review

Liver failure is associated with a high morbidity and mortality rate and is the seventh leading cause of death worldwide. Orthotopic liver transplantation remains the definitive treatment; however, because of the limited number of available organs many patients expire while on the transplant list. Currently, there are no established means for providing liver support as a means of bridging patients to transplantation or allowing for recovery from liver injury. Analogous to the clinical situation of renal failure, there is great interest in developing liver support systems that replace the metabolic and waste removal functions of the liver. These support systems are of two general types: artificial and bioartificial livers. In this review, based on a presentation from the 57th American Society of Artificial Internal Organs Annual Meeting (Washington, D.C., June 2011), we review the current status of liver support systems.

Cost-effectiveness of the artificial liver support system MARS in patients with acute-on-chronic liver failure

BACKGROUND

For patients with an acute exacerbation of chronic liver failure (ACLF), the molecular adsorbent recirculating system (MARS) can result in a prolongation of life, but data on costs and cost-effectiveness are lacking.

METHODS

A health economic evaluation of a prospective controlled cohort trial in patients with ACLF not eligible for liver transplantation with 3 years follow-up and consecutive modelling of long-term costs, outcomes and cost-effectiveness was conducted. Costs were calculated from the perspective of the German health-care system.

RESULTS

One hundred and forty-nine patients with ACLF were included of which 67 (44.9%) were treated with MARS and 82 (55.1%) assigned to the control group. Mean survival was 692 days in MARS-treated patients (33% survival after 3 years) and 453 days in control patients (15% after 3 years, logrank P = 0.022). MARS patients gained 0.66 [95% confidence interval (CI): -0.12 to 1.46] life years (LYs), determined by the bootstrap method. The mean cost difference was 19.835 euro (95% CI: 13.308-25.429) with 35639 euro for MARS-treated patients and 15804 euro for controls. Incremental costs per LY gained were 29.985 euro (95% CI: 9.441-321.761) and 43.040 euro (95% CI: 13.551-461.856) per quality-adjusted LY gained.

CONCLUSION

There is an acceptable cost-effectiveness of MARS, compared with other medical technologies presently reimbursed. Randomized controlled trials with sufficient sample size are necessary before a final recommendation for MARS can be given.

What clinical alternatives to whole liver transplantation? Current status of artificial devices and hepatocyte transplantation

Shortage of organ donors limits the number of possible liver transplantations. Alternative therapies for treatment of liver failure are currently being developed: (i) extracorporeal artificial liver devices; (ii) bioartificial liver devices using hepatocytes; and (iii) hepatocyte transplantation. The objective of these strategies is to bridge patients with liver failure until a suitable liver allograft is obtained for transplantation or the patient's own liver regenerates sufficiently to resume normal function. In this review, we discuss these strategies and summarize the current status of clinical experience.

Molecular adsorbent recirculating system (Mars) in patients with primary nonfunction and other causes of graft dysfunction after liver transplantation in the era of extended criteria donor organs

Liver dysfunction is an important cause of morbidity and mortality after orthotopic liver transplantation (OLT). The Molecular Adsorbent Recirculating System (MARS) is an albumin-based dialysis system designed to enhance the excretory function of a failing liver. MARS has been successfully used in patients affected by advanced liver disease and presenting with severe cholestasis. The aim of this study was to evaluate the safety and clinical efficacy of MARS in patients with liver dysfunction after OLT. Seven patients (primary nonfunction, 2 patients; graft dysfunction, 5 patients) fulfilled the inclusion criteria of serum bilirubin level >15 mg/dL and least 1 of the following clinical signs: hepatic encephalopathy (HE) > or = grade II, hepatorenal syndrome (HRS), and intractable pruritus. Graft and patient survival rates at 6 months were 42.8% and 57.1%, respectively. All patients tolerated MARS treatment, with no adverse event. In all patients, a decrease in serum bilirubin (P < .05), bile acids (P < .05), serum creatinine, and ammonia levels was observed after treatment with MARS. A considerable improvement of HE, as well as renal and synthetic liver functions, was observed in 4 of 5 patients with graft dysfunction, but not among those with primary nonfunction. The patients with intractable pruritus showed significant improvement of this symptom after MARS therapy. Thus, MARS is a safe, therapeutic option for the treatment of liver dysfunction after OLT. Further studies are necessary to confirm whether this treatment is able to improve both graft and patient survival.

Sorbent-based artificial liver devices: principles of operation, chemical effects and clinical results

Devices for support of patients with liver failure are of two types: bioartificial livers and artificial livers. Bioartificial livers include hepatocytes in bioreactors to provide both excretory and synthetic liver functions. Artificial livers use nonliving components to remove toxins of liver failure, supply nutrients and macromolecules. Current artificial liver devices use columns or suspensions of sorbents (including adsorbents and absorbents) to selectively remove toxins and regenerate dialysate, albumin-containing dialysate, plasma filtrate or plasma. This article reviews three artificial liver devices. Liver Dialysis uses a suspension of charcoal and cation exchangers to regenerate dialysate. MARS uses charcoal and an anion exchanger to regenerate dialysate with albumin. Prometheus uses neutral and anion exchange resins to regenerate a plasma filtrate containing albumin and small globulins. We review the operating principles, chemical effects, clinical effects and complications of use of each type of artificial liver. These devices clearly improve the clinical condition of patients with acute or acute-on-chronic liver failure. Further randomized outcome studies are necessary to prove clinical outcome benefit of the artificial liver support devices, and define what types of patients appear most amenable to therapy.

MARS dialysis in decompensated alcoholic liver disease: a single-center experience

Acute decompensation of chronically stable alcoholic liver disease (ALD) is the most common cause of terminal liver failure in developed countries. Molecular adsorbent recirculation system (MARS) is increasingly used as artificial liver support to facilitate spontaneous organ recovery. However, the experience to date and the evidence to justify this therapeutic strategy in acutely decompensated ALD are still insufficient. We report our clinical experience with MARS in 14 patients with acutely decompensated ALD (6 male subjects; median age [interquartile range], 51 [47-56] years; Child-Pugh score, 12 [10-13]; Acute Physiology and Chronic Health Evaluation (APACHE) II score, 20 [18-24]) and severely impaired liver function whose disease was unresponsive to conventional supportive care. At least 3 sessions were applied in any patient (48 sessions in total). Under MARS treatment, the following levels decreased: bilirubin (544 [489-604] to 242 [178-348] micromol/L; P<0.001), creatinine (212 [112-385] to 91 [66-210] micromol/L; P=0.002), cholestatic parameter gamma-glutamyl transpeptidase (5.9 [1.8-13.1] to 4.6 [1.8-8.3] micromol/L) (P<0.001), blood urea nitrogen (56 [32-91] to 34 [21-68] mmol/L; P=0.044), and platelet count (176 [85-241] to 84 [31-145] Gpt/L; P=0.004). In contrast, MARS failed to improve daily urine output (P=0.846), ammonia levels (P=0.340), or thromboplastin time (P=0.775). Only 3 patients survived the hospital stay (mortality 78.6%). Although MARS improved laboratory parameters of hepatic detoxification and renal function in patients with acutely decompensated ALD, the patients' mortality remained unsatisfactorily high. Our experience does not support the indiscriminative use of MARS in acutely decompensated ALD without further controlled studies.

Selective Bilirubin Removal by Plasma Treatment With Plasorba BR-350 for Early Cholestatic Graft Dysfunction

Early cholestatic graft dysfunction is a frequent cause of morbidity after orthotopic liver transplantation (OLT). We analyze the role of selective bilirubin plasma absorption (PAP) using Plasorba BR-350 in 4 OLT patients who had experienced early severe cholestatic graft dysfunction within 15 days after transplantation. Patients were treated with 3 consecutive cycles of PAP with Plasorba BR-350. The median amount of plasma treated was 7500 mL. Median treatment duration was 231 minutes. The average plasma bilirubin level was 37 +/- 1 mg/dL before PAP and decreased to 15 +/- 0.2 mg/dL at the end of the third cycle of PAP; 3 of 4 cases had progressive bilirubin normalization after PAP. The average amount of bilirubin removed from the plasma of the patients during each PAP treatment was 143 +/- 24 mg. At the beginning of each cycle of PAP, the Plasorba BR-350 was able to remove >90% of the total plasma bilirubin, a percentage that decreased to 60%, 50%, and 40% after 2 L, 4 L, and 7 L of plasma were treated, respectively. Liver biopsies performed after the third treatment showed reduced cholestasis when compared with the pretreatment biopsy specimen. The preliminary data suggested that PAP selective for bilirubin removal may not only reduce the bilirubin level, but may also improve the histological pattern of the graft in terms of reduced cholestatic signs.

Use of molecular adsorbent recirculating system in acute liver failure attributable to dengue hemorrhagic fever

Fulminant liver failure is an uncommon but life-threatening complication of severe dengue infection. Molecular adsorbent recirculating system (MARS), which reverses hepatic encephalopathy, is an emerging important element in the armamentarium of organ support in the intensive care unit in patients suffering from acute liver failure. We report an intensive care unit case of fulminant liver failure secondary to dengue hemorrhagic fever, which was supported with MARS. MARS led to rapid reversal of biochemical profile and encephalopathy, resulting in early extubation and intensive care unit discharge.

MARS in the treatment of liver failure: controversies and evidence

Molecular Adsorbent Recirculation System (MARS) is a form of extracorporeal detoxification system used as an artificial liver support system. Numerous studies have been published on the topic, with the majority of them describing the capability of MARS in removing albumin-bound toxins and improving systemic hemodynamics. Whether such improvement could be translated into survival benefit is still uncertain, given the paucity of randomized controlled trials available. The outcome of patients receiving MARS treatment is difficult to analyze because liver failure patients constitute a heterogeneous population and different subgroups carry different prognoses. An evidence-based recommendation on the timing of MARS initiation is not available and currently MARS is usually commenced for hyperbilirubinemia or presence of complications of liver failure. MARS is in general a safe procedure, but there are still potential complications that need to be cautioned, along with various operative issues that are worth attention. The future prospects of MARS would rely on the completion of adequately powered randomized controlled trials.

Molecular Adsorbent Recirculating System in Liver Transplantation: Safety and Efficacy

We assessed the safety and clinical efficacy of the Molecular Adsorbent Recirculating System (MARS) in liver failure patients admitted to our intensive care unit (ICU) from May 2000 to February 2006. Of 28 adult patients with bilirubin >15 mg/dL and hepatic encephalopathy (HE) grade > or =2 or hepato-renal syndrome, 22 patients were included in the study, because 6 patients were older than 65 years of age or showed recent alcohol abuse or extrahepatic malignancy. Patients were assigned to 2 groups according to whether MARS therapy was associated with a transplantation procedure: 11 patients received MARS therapy and liver transplantation (OLT group) and 11 patients received MARS therapy alone (non-OLT group). Five of 11 patients in the OLT group were listed for transplantation and 6 patients with graft failure for retransplantation. The patients in the OLT and non-OLT groups were similar in MELD, SOFA, and SAPS scores. All patients were stable and free from complications. MARS significantly reduced bilirubin, bile acids, and blood urea nitrogen (BUN) levels in both groups (P < .05), whereas a significant decrease in ammonia level was observed in the OLT group. Patient survival rates at 3 and 6 months in the OLT group were 91% and 73%, respectively, and in the non-OLT group, 9% and 9%, respectively (P < .001). MARS was safe and well tolerated, improving biochemical parameters, neurological function, and pruritus. In terms of survival, the use of MARS alone was not effective due to the high rate of multiple organ failure. Nevertheless, the association of MARS with a transplant/retransplantation procedure was highly effective.

Acute liver failure: a review

Since publication of the first descriptions of acute liver failure (ALF) as a distinct clinical entity in the 1950's, the understanding of the pathophysiologic mechanisms involved and the management options have increased substantially. ALF still represents a major challenge for todays hepatologists, because it can rapidly lead to multiorgan failure and death that may be preventable with appropriate intervention. This article summarizes the basic patho-physiology underlying ALF, compares epidemiologic trends in the United States, the United Kingdom, and the Far East, and reviews prognostic markers and treatment options for ALF.