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

The future of extracorporeal support

Extracorporeal therapy has expanded significantly over the past few decades from solely artificial renal replacement therapy. In patients with multiple organ dysfunction syndrome, it becomes necessary to provide multiple organ support therapy. Technological advances have opened the door to a multifaceted intervention directed at supporting the function of multiple organs through the treatment of blood. Indications for "old" therapies such as hemofiltration and adsorption have been expanded, and using these therapies in combination further enhances blood detoxification capabilities. Furthermore, new devices are constantly in development. Nanotechnology allows us to refine membrane characteristics and design innovative monitoring/biofeedback devices. Miniaturization is leading down the path of wearable/implantable devices. With the incorporation of viable cells within medical devices, these instruments become capable not only of detoxification but synthetic functions as well, bringing us closer to the holy grail of complete replacement of organ function. This article provides a brief overview of current and future direction in extracorporeal support in the critical care setting.

Liver support devices

PURPOSE OF REVIEW

Liver support devices are used either as a bridge to liver transplantation or liver recovery in patients with acute or acute-on-chronic liver failure. The review analyzes the recent literature and asks if the current enthusiasm for these devices is justified.

RECENT FINDINGS

Many liver support devices exist and are discussed. Clinical data on artificial devices are rapidly emerging, especially on the molecular adsorbents recirculating system, and fractionated plasma separation and adsorption (Prometheus). While hepatic encephalopathy is improved by the molecular adsorbents recirculating system and probably Prometheus too, neither system has been shown to improve survival. Less clinical data exist for bioartificial support devices. These may use human hepatocytes, such as the extracorporeal liver assist device, although most devices use porcine hepatocytes, such as HepatAssist.

SUMMARY

Enthusiasm in liver support devices is justified as many nonrandomized studies have suggested some biochemical and clinical benefits. The results of several ongoing multicenter randomized controlled trials are anxiously awaited. Meanwhile, because mortality without liver transplantation remains high despite the use of liver support devices, these devices should only be used in the research setting or by experts proficient in their use and as a bridge to liver transplantation rather than liver recovery.

A review of albumin binding in CKD

Hypoalbuminemia is associated with excess mortality in patients with kidney disease. Albumin is an important oxidant scavenger and an abundant carrier protein for numerous endogenous and exogenous compounds. Several specific binding sites for anionic, neutral, and cationic ligands were described. Overall, the extent of binding depends on the ligand and albumin concentration, albumin-binding affinity, and presence of competing ligands. Chronic kidney disease affects all these determinants. This may result in altered pharmacokinetics and increased risk of toxicity. Renal clearance of albumin-bound solutes mainly depends on tubular clearance. Dialytic clearance by means of conventional hemodialysis/hemofiltration and peritoneal dialysis is limited. Other epuration techniques combining hemodialysis with adsorption have been developed. However, the benefit of these techniques remains to be proved.

What's new in the treatment of ascites and spontaneous bacterial peritonitis

In recent years, there have been important advances in the clinical management of ascites and its related complications, such as hyponatremia, hepatorenal syndrome (HRS), and spontaneous bacterial peritonitis (SBP). Moreover, new drugs are currently being investigated for their potential usefulness in managing these complications. This article is not intended to comprehensively review all the literature published in recent years; rather, the authors discuss only studies they believe represent a potentially significant advance in this field. The following review is divided into two parts; the first discusses ascites and renal function abnormalities, including hyponatremia and HRS, and the second discusses SBP management.

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.

Model for end-stage liver disease score and systemic inflammatory response are major prognostic factors in patients with cirrhosis and acute functional renal failure

Although it is often functional at presentation, acute renal failure has a poor prognosis in patients with cirrhosis. The role of inflammation, a key event in the outcome of cirrhosis, has never been studied in this setting. We aimed to investigate the predictive factors of mortality in patients with cirrhosis and acute functional renal failure, specifically in relation to inflammatory events. One hundred consecutive patients with cirrhosis from 5 French hospitals were prospectively included at the day of onset of acute renal failure. Medical history, treatments, and procedures during the month before inclusion were recorded. Physical examination, blood and urinary chemistries, and renal ultrasound examination were performed. The presence of systemic inflammatory response syndrome (SIRS), infection, and sepsis was assessed. The primary outcome was in-hospital mortality. The mechanism of renal failure was functional in 83 patients. Causes of renal failure were hypovolemia (34%), hepatorenal syndrome without ongoing infection (17%), hepatorenal syndrome with ongoing infection (16%), nephrotoxicity (2%), and multifactorial (31%). SIRS was observed in 41% of patients, 56% of them with infection. In-hospital mortality was 68% in patients with SIRS and 33% in patients without (P = 0.001). In multivariate analysis, only model for end-stage liver disease score and presence of SIRS, but not infection, remained associated with a poor outcome.

CONCLUSION

The presence of SIRS, with or without infection, is a major independent prognostic factor in patients with cirrhosis and acute functional renal failure. This suggests that preventing and treating SIRS could decrease mortality in patients with cirrhosis and acute renal failure.

Acute renal dysfunction in liver diseases

Renal dysfunction is common in liver diseases, either as part of multiorgan involvement in acute illness or secondary to advanced liver disease. The presence of renal impairment in both groups is a poor prognostic indicator. Renal failure is often multifactorial and can present as pre-renal or intrinsic renal dysfunction. Obstructive or post renal dysfunction only rarely complicates liver disease. Hepatorenal syndrome (HRS) is a unique form of renal failure associated with advanced liver disease or cirrhosis, and is characterized by functional renal impairment without significant changes in renal histology. Irrespective of the type of renal failure, renal hypoperfusion is the central pathogenetic mechanism, due either to reduced perfusion pressure or increased renal vascular resistance. Volume expansion, avoidance of precipitating factors and treatment of underlying liver disease constitute the mainstay of therapy to prevent and reverse renal impairment. Splanchnic vasoconstrictor agents, such as terlipressin, along with volume expansion, and early placement of transjugular intrahepatic portosystemic shunt (TIPS) may be effective in improving renal function in HRS. Continuous renal replacement therapy (CRRT) and molecular absorbent recirculating system (MARS) in selected patients may be life saving while awaiting liver transplantation.

[Hepatorenal syndrome]

Hepatorenal syndrome (HRS) is a severe complication in patients with cirrhosis and ascites. Renal insufficiency is functional and is caused by renal vasoconstriction. HRS occurs in 10% of patients with advanced cirrhosis. Diagnosis of HRS is based on ruling out other causes of renal insufficiency. There are two types of HRS: type 1 has rapid onset and progressive course and a mean survival of 15 days without treatment, while type 2 is less severe and progressive, with a mean survival of 6 months. Definitive treatment of HRS is liver transplantation. However, in the last few years administration of vasoconstrictive drugs or placement of portosystemic shunts have been shown to be effective in reversing HRS. Therefore, these measures may be used as a bridge before liver transplantation is performed. Finally, the risk of developing HRS in the context of spontaneous bacterial peritonitis can be prevented by administering albumin together with the corresponding antibiotics. In cases of severe acute alcoholic hepatitis, pentoxifylline can be administered.

Noradrenalin vs terlipressin in patients with hepatorenal syndrome: a prospective, randomized, unblinded, pilot study

BACKGROUND/AIMS

Treatment of hepatorenal syndrome (HRS) is based on vasoconstrictors. Terlipressin is the one with the soundest evidence. Noradrenalin has been suggested as an effective alternative. The current study was aimed at assessing the efficacy and safety of noradrenalin vs terlipressin in patients with HRS.

METHODS

Twenty-two consecutive cirrhotic patients with HRS (9 with HRS type 1; 13 with HRS type 2) were included. Patients were randomly assigned to be treated with noradrenalin (0.1-0.7 microg/kg/min) and albumin (10 patients) or with terlipressin (1-2 mg/4h) and albumin (12 patients). Treatment was administered until HRS reversal or for a maximum of two weeks. Patients were followed-up until liver transplantation or death.

RESULTS

Reversal of HRS was observed in 7 of the 10 patients (70%) treated with noradrenalin and in 10 of the 12 patients (83%) treated with terlipressin, p=ns. Treatment led in both groups to a significant improvement in renal and circulatory function. No patient developed signs of myocardial ischemia.

CONCLUSIONS

Data from this unblinded, pilot study suggest that noradrenalin is as effective and safe as terlipressin in patients with HRS. These results would support the use of noradrenalin, a cheap and widely available drug, in the management of these patients.

Hepatorenal syndrome

Hepatorenal syndrome (HRS) is a “functional” and reversible form of renal failure that occurs in patients with advanced chronic liver disease. The distinctive hallmark feature of HRS is the intense renal vasoconstriction caused by interactions between systemic and portal hemodynamics. This results in activation of vasoconstrictors and suppression of vasodilators in the renal circulation. Epidemiology, pathophysiology, as well as current and emerging therapies of HRS are discussed in this review.

Adult Living Donor Liver Transplantation in Singapore: The Asian Centre for Liver Diseases and Transplantation Experience

Introduction: Living donor liver transplantation (LDLT) has progressed dramatically in Asia due to the scarcity of cadaver donors and is increasingly performed in Singapore. The authors present their experience with adult LDLT. Materials and Methods: Adult LDLTs performed at the Asian Centre for Liver Diseases and Transplantation, Singapore from 20 April 2002 until 20 March 2006 were reviewed. All patients received right lobe grafts and were managed by the same team throughout this period. Data were obtained by chart review. This study presents both recipient and donor outcomes in a single centre. Results: A total of 65 patients underwent LDLT. Forty-three were genetically related while 22 were from emotionally-related donors. The majority were chronic liver failure while 14% were acute. The most common indication for LDLT was end-stage liver disease due to hepatitis B virus. A total of 22 patients with hepatoma were transplanted and overall 1-year disease specific survival was 94.4%. The mean model for end-stage liver disease (MELD) score was 17.4 ± 9.4 (range, 6 to 40). Six patients had preoperative molecular adsorbent recycling system (MARS) dialysis with 83% transplant success rate. The mean follow-up was 479.2 days with a median of 356 days. One-year overall survival was 80.5%. There was 1 donor mortality and morbidity rate was 17%. Our series is in its early stage with good perioperative survival outcome with 1-month and 3-month actuarial survival rates of 95.4% and 87.3% respectively. Conclusion: The study demonstrates that LDLT can be done safely with good results for a variety of liver diseases. However, with dynamically evolving criteria and management strategies, further studies are needed to maximise treatment outcome. Key words: Donor and recipient outcome, End-stage liver disease, Hepatitis, Hepatocellular carcinoma, Living donor liver transplantation

Modifications of Intracranial Pressure After Molecular Adsorbent Recirculating System Treatment in Patients With Acute Liver Failure: Case Reports

Cerebral dysfunction may be fatal in patients with acute liver failure (ALF); intracranial pressure (ICP) monitoring may be mandatory to direct measures to prevent further cerebral edema. Recently the introduction of dialysis with the molecular adsorbent recirculating system (MARS) has improved the outcomes among patients with ALF. The aim of this study was to evaluate ICP changes after MARS treatment among patients with ALF.

METHODS

Three patients -- 14, 18 and 16 years old -- were admitted to the ICU for acute liver failure induced by HBV in two cases and by acetaminophen in the other one. Because of Glasgow Coma Score (GCS) <8, they were intubated and ventilated to protect the airway and maintain moderate hypocapnia. Invasive monitoring of intracranial pressure MARS treatments were performed in all patients.

RESULTS

The patients received MARS treatments every day after their admission to liver transplantation. After MARS therapy the ICP decreased on average from 21 to 7 mm Hg. Significant hemodynamic modifications were not observed and their neurological conditions improved.

CONCLUSION

MARS treatment improved the clinical pictures of these patients increasing the available time to obtain an urgent liver graft.

The patient with refractory ascites

Refractory ascites indicates advanced chronic liver disease and represents a therapeutic challenge. It may be triggered by spontaneous bacterial peritonitis and denotes poor prognosis. While liver transplantation is the ultimate treatment, for the relief of ascites therapeutic paracentesis with iv-administration of albumin and/or transjugular intrahepatic portosystemic shunt (TIPS) are well established. With rapid deterioration of renal function patients can develop hepatorenal syndrome. There is increasing evidence that these patients can be bridged to transplantation with vasopressin analogs (terlipressin) and albumin.

Removal of bile acids by two different extracorporeal liver support systems in acute-on-chronic liver failure

Acute-on-chronic liver failure (ACLF) is accompanied by marked intrahepatic cholestasis leading to accumulation of cytotoxic bile acids. Extracorporeal liver support systems efficiently remove bile acids, but their effect on bile acid composition in ACLF is unknown. The aim of the present study was to compare elimination of individual plasma bile acids by albumin dialysis (Molecular Adsorbents Recirculating System, MARS) and fractionated plasma separation (Prometheus). Eight consecutive patients with ACLF underwent alternating 6-hour sessions with MARS or Prometheus in a randomized, cross-over design. Serum samples were obtained before, during, and after each treatment, and individual bile acids including cholic acid and chenodeoxycholic acid (CDCA) were measured by gas chromatography. MARS and Prometheus removed total bile acids to a similar extent (reduction ratio, 45% and 46%, respectively). Both devices cleared cholic acid more efficiently than did CDCA. The molar fraction of CDCA (fCDCA) was elevated at baseline and correlated with the degree of liver dysfunction. Prometheus but not MARS treatments further increased fCDCA. Although both devices eliminate total bile acids to a similar extent, clearance of individual bile acids is different, leading to a slight change of the bile acid profile toward hydrophobic bile acids during Prometheus treatments.

Artificial liver support with the molecular adsorbent recirculating system: activation of coagulation and bleeding complications

BACKGROUND

Numerous, mostly uncontrolled, observations suggest that artificial liver support with the Molecular Adsorbent Recirculating System (MARS) improves pathophysiologic sequelae and outcome of acute and acute-on-chronic liver failure. MARS is felt to be safe, but extracorporeal circuits may activate coagulation.

OBJECTIVE

To assess the frequency of and risk factors for activation of coagulation during MARS treatment.

PATIENTS/METHODS

Retrospective analysis of coagulopathy/bleeding complications observed during 83 consecutive MARS sessions in 21 patients (11 men; median age 46 years; median three sessions per patient; median duration of session 8 h).

RESULTS

Nine clinically relevant episodes of coagulopathy/bleeding were observed in eight patients, forced to premature cessation of MARS in seven and ended lethal in four. Four complications occurred during the first, five during later (third to seventh) MARS sessions and two bleeders tolerated further sessions without complications. Coagulation parameters worsened significantly also during MARS sessions not associated with bleeding (P< or =0.004). In univariate analysis, patient's age, vasopressor therapy, pretreatment INR, fibrin D-dimer and fibrinogen concentrations, but not severity of underlying disease (MELD, Child-Pugh, SAPS II scores), were significantly associated with coagulopathy (P<0.05). Only patient's age, fibrin D-dimer level and INR were retained in a multivariate model correctly classifying 98% of sessions without, but only 33% with complications.

CONCLUSION

Coagulation is frequently activated during MARS therapy, potentially leading to bleeding complications and mortality.

Pretransplant management of the cirrhotic patient

Cirrhosis is the twelfth commonest cause of death in the United States, with more than 27,000 deaths and more than 421,000 hospitalizations annually. Currently, there are more than 17,000 patients awaiting liver transplantation in the United States across the 11 United Network for Organ Sharing regions. Approximately 10% of such patients will die awaiting transplantation.

Technology Insight: artificial extracorporeal liver support—how does Prometheus® compare with MARS®?

Artificial extracorporeal liver support or 'liver dialysis' has been used in patients with severe liver failure with increasing frequency since the Molecular Adsorbents Recirculating System (MARS), a variant of albumin dialysis, was introduced in 1999. Nevertheless, liver dialysis must still be thought of as experimental because its contribution to improved patient survival has not been proven in large randomized trials. Prometheus is a novel device for fractionated plasma separation via an albumin-permeable filter that was developed to improve removal of albumin-bound toxins. Initial studies have proven clinical use of Prometheus to be feasible and safe. Head-to-head comparisons of Prometheus and MARS have shown treatment with the former to be more efficient with respect to removal of most albumin-bound and water-solved markers. As controlled studies with clinical end points are lacking, it is not known whether the observed greater detoxification capacity of Prometheus will translate into clinical benefit; two small studies indicate that there might be a beneficial effect in hepatic encephalopathy and pruritus. In a recent randomized comparison of MARS and Prometheus, however, hemodynamic improvement was observed in response to MARS, but not Prometheus, treatment. A large randomized controlled trial investigating the effect of Prometheus on survival--the HELIOS study--has been initiated. First results are expected in 2008 and will be crucial to establishing a role for Prometheus in the field of extracorporeal liver support.

Acute liver failure: liver support therapies

PURPOSE OF REVIEW

We summarize the therapeutic approach to patients with acute liver failure with the main focus on bioartificial and artificial liver support. We also describe specific and general therapeutic approaches based upon recent advances in the understanding of the pathophysiology of acute liver failure.

RECENT FINDINGS

Bioartificial liver support systems use hepatocytes in an extracorporeal device connected to the patient's circulation. Artificial liver support is intended to remove protein-bound toxins and water-soluble toxins without providing synthetic function. Both systems improve clinical and biochemical parameters and can be applied safely to patients. Although bioartificial liver-assist devices have not been shown to improve the survival of patients with acute liver failure, further development is underway. Artificial liver support systems have been shown to alter several pathophysiological mechanisms involved in the development of acute liver failure but survival data are still limited.

SUMMARY

Mortality in patients with acute liver failure is still unacceptably high. The most effective treatment, liver transplantation, is a limited resource and so other therapeutic options to bridge patients to recovery or stabilization have to be considered. Better understanding of the pathophysiology of acute liver failure and device development is necessary to achieve the elusive goal of effective extracorporeal liver assist.

Anticoagulation Minimization Is Safe and Effective in Albumin Liver Dialysis Using the Molecular Adsorbent Recirculating System

The molecular adsorbent recirculating system (MARS) is a blood purification device with renal and hepatic dialytic effects. This study examined the use of low-dose unfractionated heparin in MARS. This was a prospective, observational study of 15 MARS treatment sessions (mean duration per treatment cycle = 12.2 +/- 4.5 h) in four patients with severe acute decompensation of chronic liver disease (n = 3) and fulminant hepatic failure (n = 1) treated with intermittent MARS. All patients were critically ill (APACHE II 24.8 +/- 3.3). Renal dialysis was with continuous hemofiltration and/or slow low-efficiency dialysis. One MARS session was terminated because of vascular access occlusion (1/15; 6.7%). Bleeding was noted in two sessions (2/15; 13%). Twelve MARS sessions were heparin-free and three treatments were with mean heparin dose of 833 +/- 382 IU. Serum biochemical parameters pre- and post-MARS were total bilirubin (micromol/L): 409.4 +/- 141.6 versus 282.9 +/- 90, P < 0.05; plasma ammonia (micromol/L): 44.3 +/- 21.2 versus 28.8 +/- 20.2, P = 0.002; urea (mmol/L): 15.9 +/- 11.8 versus 7.9 +/- 6.6, P = 0.002; creatinine (micromol/L): 252.4 +/- 151.9 versus 150.1 +/- 96.6, P = 0.003. Pre-MARS versus post-MARS systolic (SBPs) and diastolic (DBPs) blood pressures (mm Hg) were SBP = 129.2 +/- 27.7 versus 124 +/- 25, P = 0.838; and DBP = 60.7 +/- 15.3 versus 56 +/- 13, P = 0.595. Prothrombin time (PT), activated partial thromboplastin time (aPTT) and platelet count (Plt) pre- and post-MARS were PT(s): 22 +/- 7.9 versus 23.8 +/- 10.2, P = 0.116; aPTT (s): 64.5 +/- 40.9 versus 85.5 +/- 50.6, P = 0.092; and Plt (x10(3)/mm(3)): 87 +/- 67.6 versus 68.8 +/- 39, P = 0.098. MARS priming with heparin saline was safe. Heparin-minimized MARS did not compromise circuit function and longevity in extended intermittent MARS.

MARS: a futile tool in centres without active liver transplant support

BACKGROUND AND AIM

Studies on Molecular Adsorbent Recycling Systems (MARS) showed inconclusive survival benefits.

PATIENTS AND METHOD

We evaluated the efficacy of MARS for patients with either acute liver failure (ALF) or acute-on-chronic liver failure (AoCLF) at our centre, from February 2002 till April 2006 retrospectively.

RESULTS

Fifty ALF patients underwent median (range) three (1-10) sessions of MARS. Acute exacerbations of chronic hepatitis B (n=26) and drug-induced liver injury (n=12) were the commonest causes. Living donors were available in 6, 2 paediatric patients underwent left lobe and four adults underwent right lobe living donor liver transplant. Among the 44 ALF patients without a suitable living donor, one underwent deceased donor liver transplant and survived, another 19-year-old male with acute exacerbations of chronic hepatitis B recovered without transplant, and the rest died. Twenty-six had AoCLF and underwent four (1-10) MARS sessions. Sepsis (n=16) and upper gastrointestinal bleeding (n=4) were the commonest precipitating factors. None had a suitable living or deceased donor, suitable for transplantation during their hospitalization. Only one of 26 AoCLF patients survived the hospitalization, but the survivor died of sepsis 1 month later.

CONCLUSION

In this non-randomized study, survival after MARS was related to the availability of transplant, and in patients where living or deceased donor transplant was unavailable, MARS was of little benefit. Randomized-controlled trials on MARS((R)) are urgently needed to clarify its clinical utility.

Drug insight: the role of albumin in the management of chronic liver disease

Albumin is the most abundant protein in the circulation. Its main physiologic function is to maintain colloid osmotic pressure. Better understanding of albumin's other physiologic functions has expanded its application beyond maintenance of intravascular volume. In patients with cirrhosis, albumin has been used as an adjunct to diuretics to improve the diuretic response. It has also been used to prevent circulatory dysfunction developing after large-volume paracentesis. Newer indications in cirrhotic patients include preventing hepatorenal syndrome in those with spontaneous bacterial peritonitis, and treating established hepatorenal syndrome in conjunction with vasoconstrictor therapies. The use of albumin for many of these indications is controversial, mostly because of the paucity of well-designed, randomized, controlled trials. The cost of albumin infusions, lack of clear-cut benefits for survival, and fear of transmitting unknown viruses add to the controversy. The latest indication for albumin use in cirrhotic patients is extracorporeal albumin dialysis, which has shown promise for the treatment of hepatic encephalopathy; its role in hepatorenal syndrome or acute on chronic liver failure has not been established. Efforts should be made to define the indications for albumin use, dose of albumin required and predictors of response, so that patients gain the maximum benefit from its administration.

Hepatorenal syndrome: an update

Hepatorenal syndrome (HRS) is the development of renal failure in patients with chronic previous liver disease, without clinical or laboratory evidence of previous kidney disease. It affects up to 18% of cirrhotic patients with ascites during the first year of follow-up, reaching 39% in five years and presenting a survival of about two weeks after its establishment. HRS diagnosis is based on clinical and laboratory data. The occurrence of this syndrome is related to the mechanism for ascites development, involving vasoconstriction, low renal perfusion, water and sodium retention, increased plasma volume, and consequent overflow at the splanchnic level. Renal vasoactive mediators like endothelin 1, thromboxane A2, and leukotrienes are also involved in the genesis of this syndrome, which culminates in functional renal insufficiency. The treatment of choice can be pharmacological or surgical, although liver transplantation is the only permanent and effective treatment, with a four-year survival rate of up to 60%. Liver function recovery is usually followed by renal failure reversion. Early diagnosis and timely therapeutics can increase life expectancy for these patients while they are waiting for liver transplantation as a definitive treatment.

Treatment of hepatorenal syndrome

<zakljucak> Hepatorenalni sindrom je funkcionalna insuficijencija bubrega u sklopu terminalne insuficijencije jetre. U patogenezi ovog sindroma ucestvuju hemodinamske promene (snizeni srednji arterijski pritisak i perfuzioni pritisak bubrega) i povecano stvaranje sistemskih i bubreznih vazoaktivnih medijatora sa stimulacijom bubreznog simpatickog sistema. Standardna medicinska farmakoloska terapija usmerena je na prethodno navedene patofizioloske poremecaje. U poslednje vreme postupci detoksikacije, npr. jedan od vidova albuminske dijalize, pojavljuju se sve vise u lecenju bolesnika sa HRS, ali se jos ne preporucuju kao standardna procedura. Oba vida lecenja preduzimaju se samo kao premoscenje perioda do transplantacije jetre ili u slucajevima kada se ocekuje oporavak funkcije jetre, jer bubrezna funkcija direktno zavisi od funkcije jetre. Standardna hemodijaliza ne pomaze u poboljsanju funkcije bubrega. Jedino kauzalno resenje ovog problema donosi transplantacija jetre.

Diagnosis and treatment of acute renal failure in patients with cirrhosis

In patients with cirrhosis, acute renal failure is due to prerenal failure (a result of decreased renal perfusion) and tubular necrosis. There are 3 main causes of prerenal failure: 'true hypovolemia' (which complicates hemorrhage, gastrointestinal or renal fluid losses), sepsis, and type 1 hepatorenal syndrome (HRS). Prerenal failure may also be due to the administration of non-steroidal antiinflammatory drugs, or intravascular radiocontrast agents. Prerenal failure is reversible after restoration of renal blood flow. Treatments target the cause of hypoperfusion, and fluid replacement is used to treat 'non-HRS' prerenal failure. In patients with type 1 HRS with very low short-term survival rate, liver transplantation is the ideal treatment. Systemic vasoconstrictor therapy with terlipressin (combined with intravenous human albumin), noradrenaline (combined with albumin and furosemide) or midodrine (combined with octreotide and albumin) may improve renal function in patients with type 1 HRS waiting for liver transplantation. MARS (for Molecular Adsorbent Recirculating System) and the transjugular intrahepatic portosystemic shunt may also improve renal function in these patients. In patients with cirrhosis, acute tubular necrosis is mainly due to an ischemic insult to the renal tubules. Studies are needed on the natural course and treatment (e.g., renal-replacement therapy) of acute tubular necrosis in patients with cirrhosis.

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.

Brain edema and intracranial hypertension in fulminant hepatic failure: Pathophysiology and management

Intracranial hypertension is a major cause of morbidity and mortality of patients suffering from fulminant hepatic failure. The etiology of this intracranial hypertension is not fully determined, and is probably multifactorial, combining a cytotoxic brain edema due to the astrocytic accumulation of glutamine, and an increase in cerebral blood volume and cerebral blood flow, in part due to inflammation, to glutamine and to toxic products of the diseased liver. Validated methods to control intracranial hypertension in fulminant hepatic failure patients mainly include mannitol, hypertonic saline, indomethacin, thiopental, and hyperventilation. However all these measures are often not sufficient in absence of liver transplantation, the only curative treatment of intracranial hypertension in fulminant hepatic failure to date. Induced moderate hypothermia seems very promising in this setting, but has to be validated by a controlled, randomized study. Artificial liver support systems have been under investigation for many decades. The bioartificial liver, based on both detoxification and swine liver cells, has shown some efficacy on reduction of intracranial pressure but did not show survival benefit in a controlled, randomized study. The Molecular Adsorbents Recirculating System has shown some efficacy in decreasing intracranial pressure in an animal model of liver failure, but has still to be evaluated in a phase III trial.

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.

Systemic and regional hemodynamics in pigs with acute liver failure and the effect of albumin dialysis

OBJECTIVE

Acute liver failure (ALF) is haemodynamically characterized by a hyperdynamic circulation. The aims of this study were to investigate the systemic and regional haemodynamics in ALF, to measure changes in nitric oxide metabolites (NOx) and to evaluate whether these haemodynamic disturbances could be attenuated with albumin dialysis.

MATERIAL AND METHODS

Norwegian Landrace pigs (23-30 kg) were randomly allocated to groups as controls (sham-operation, n = 8), ALF (hepatic devascularization, n = 8) and ALF + albumin dialysis (n = 8). Albumin dialysis was started 2 h after ALF induction and continued for 4 h. Systemic and regional haemodynamics were monitored. Creatinine clearance, nitrite/nitrate and catecholamines were measured. A repeated measures ANOVA was used to analyse the data.

RESULTS

In the ALF group, the cardiac index increased (PGT < 0.0001), while mean arterial pressure (PG = 0.02) and systemic vascular resistance decreased (PGT < 0.0001). Renal resistance (PG = 0.04) and hind-leg resistance (PGT = 0.003) decreased in ALF. There was no difference in jejunal blood flow between the groups. ALF pigs developed renal dysfunction with increased serum creatinine (PGT = 0.002) and decreased creatinine clearance (P = 0.02). Catecholamines were significantly higher in ALF, but NOx levels were not different. Albumin dialysis did not attenuate these haemodynamic or renal disturbances.

CONCLUSIONS

The haemodynamic disturbances during the early phase of ALF are characterized by progressive systemic vasodilatation with no associated changes in metabolites of NO. Renal vascular resistance decreased and renal dysfunction developed independently of changes in renal blood flow. After 4 h of albumin dialysis there was no attenuation of the haemodynamic or renal disturbances.

Albumin regeneration in liver support-comparison of different methods

Albumin is the most abundant human plasma protein. Among many other functions it is an important transporter of hydrophobic internal and external substances such as intermediate and end products of metabolism and drugs. In liver failure the albumin binding capacity is decreased because of a disproportion between available albumin molecules caused by decreased hepatic synthesis and hydrophobic toxins because of decreased hepatic clearance. The resulting increase in plasma and tissue concentrations of these substances is associated with multiple organ dysfunctions frequently seen in severe liver failure. The scope of the present article is to compare different liver support strategies with regard to their ability to regenerate the patients albumin pool by removing albumin-bound toxins. Most prominent technique in this group is the molecular adsorbent recirculating system (MARS). It will be compared with single pass albumin dialysis (SPAD), fractionated plasma separation and adsorption system (FPSA, Prometheus), and plasma perfusion/bilirubin adsorption with special regard to efficacy and selectivity.

Bioartificial liver: its pros and cons

Both the large variety of liver functions for maintaining body homeostasis and the proven effectivity of whole liver transplantation in the therapy of acute liver failure (ALF), are important reasons to presume that cell-free liver support systems will not be able to adequately support the failing liver. Accordingly, bioartificial liver (BAL) systems have shown their efficacy in experimental ALF models in small and large animals, and have shown to be suitable and safe in phase 1 studies in humans with ALF. However, the optimal BAL system is still under development. Important issues are the source of the cellular component and the configuration of the BAL system with regard to cell attachment, mass transfer characteristics and oxygenation at site. The deficiency of all BAL systems to excrete bile effectively is another important topic for improvement. The great challenge for the future is to develop a well-functioning and safe human hepatic cell line which can replace the widely used porcine (xenogeneic) hepatocytes. Theoretically, a combination of a cell-free liver support system and a BAL system might be optimal for the treatment of ALF patients in the near future.

Principles of bound solute dialysis

Toxins that bind to albumin in the bloodstream and are associated with progressing liver failure have proven refractory to removal by conventional hemodialysis. Such toxins can, however, be removed by adding a binder to the dialysate that serves to capture the toxin as it is dialyzed across the membrane. Several approaches based upon this concept are in various stages of clinical evaluation. The thermodynamic basis common to these approaches has been used to develop an engineering description of 'bound solute dialysis' which has further been used to define the clinical expectations and limitations of the approach. Three dimensionless, independently controllable, operating parameters emerged from this analysis (i): kappa, the dialyzer mass transfer/blood flow rate ratio (clinical range: 0.5-2.5); (ii) alpha, the dialysate/blood flow rate ratio (clinical range: 0.1-2.0); and (iii) beta, the dialysate/blood binder concentration ratio (clinical range: 0.02-5.0). In the absence of binder in the dialysate, bound toxin removal is sensitive to kappa and alpha, with greater removal associated with greater kappa and/or alpha. Bound toxin removal, however, is dependent primarily upon kappa and independent of alpha and beta once a small amount of binder, beta > 0.02, is added to the dialysate. The improvement in bound toxin removal over conventional hemodialysis is dependent upon how tightly the toxin binds albumin ranging from a 6-fold increase for a relatively tightly bound solute such as unconjugated bilirubin, to 1.5-fold increase for a less tightly bound drug such as warfarin at 24 h perfusion time. Clinically, bound solute dialysis can be practiced in single-pass mode with as little as 1-2 g albumin/L dialysate. Because of the constraints imposed by the thermodynamic nature of the process, intervention should be made as early in the disease progression as feasible.

The management of severe alcoholic liver disease and variceal bleeding in the intensive care unit

PURPOSE OF REVIEW

To address recent advances in the understanding and management of alcohol-related chronic liver disease and its acute complications.

RECENT FINDINGS

Refinements have been made in the prognosis and treatment of alcoholic hepatitis, and new insights have been gained into the pathophysiology of the hepatorenal syndrome. Further trial evidence has emerged concerning therapy in the hepatorenal syndrome, and there has been some clarification of the benefits and risks relating to albumin dialysis/extracorporeal liver support, and consensus in the early management of variceal haemorrhage.

SUMMARY

Recent developments have led to modifications in the standard of care of patients with severe alcoholic liver disease, many of which are highly applicable to the general critical care setting. These changes apply specifically to alcoholic hepatitis, the hepatorenal syndrome and variceal bleeding, common conditions with a high mortality rate, upon which changes in practice can have a significant impact.

Prometheus versus molecular adsorbents recirculating system: comparison of efficiency in two different liver detoxification devices

Albumin dialysis by the molecular adsorbents recirculating system (MARS) and by fractionated plasma separation, adsorption, and dialysis (Prometheus[PROM]) represent novel nonbiological liver support systems specifically designed to remove albumin-bound substances. Preliminary evidence suggests a favorable impact of MARS on the course and outcome of liver failure. This study aimed at comparing the detoxification capacity of both devices. For this purpose, we performed a retrospective analysis on data prospectively collected in patients with acute-on-chronic liver failure treated with either the MARS (n = 9) or the PROM (n = 9) device on 2-5 consecutive days. Each treatment was performed for at least 5 h at identical blood and dialysate flows. Blood clearances were calculated during the first treatment session for urea nitrogen, creatinine, total bilirubin, and bile acids from paired arterial and venous line samples after 1, 4, and 6 h of treatment. Reduction ratios for all single-treatment sessions, and the overall treatment phase, were calculated from pretreatment and post-treatment values. For all markers but bile acids, the single-treatment as well as the overall treatment phase reduction ratios obtained with PROM were significantly higher compared with those obtained with MARS. PROM led at all time points to higher clearances for all evaluated solutes. Blood clearances of protein-bound substances declined over time with MARS, but not with PROM. In conclusion, a significant decline in the serum level of water-soluble and protein-bound toxins was achieved with both devices. PROM produces higher blood clearances for most toxins, which results in higher delivered treatment doses compared with a matching treatment with MARS.

[Hepatorenal syndrome]

Hepatorenal syndrome (HRS) is defined as the development of renal insufficiency in chronic liver disease with portal hypertension when other causes of functional renal failure are excluded. Incidence in patients with refractory ascites is 8%, with an overall incidence of renal failure in end stage liver disease being 75%. HRS is predictive for the prognosis of end stage liver failure but its pathogenesis is complex and currently not fully understood.

Artificial liver support at present and in the future

Liver failure is a fatal disease. Liver transplantation is the only established treatment for liver failure; however, donor shortages remain problematic. In the United States and Europe, artificial livers as a bridge to liver transplantation are being considered. In Japan, we have taken a different approach to the treatment of end-stage liver diseases because of the characteristics of the health-care insurance system, regulated by the government. Furthermore, cadaveric liver transplantations are unsuited to the social mores of Japanese culture. Practically speaking, we believe that plasma exchange (PE) and continuous hemodiafiltration (CHDF) are the most effective therapies for the treatment of liver failure, although randomized controlled studies are needed to determine their effects. Overall, we believe that the first line of treatment for liver failure should be PE and CHDF, and the second line should be bioartificial liver support. In the near future, we hope that both gene therapy and regenerative medicine will contribute to the development of a functional artificial liver.

New management options for end-stage chronic liver disease and acute liver failure: potential for pediatric patients

The management of children with end-stage chronic liver disease and acute liver failure mandates a multidisciplinary approach and intense monitoring. In recent years, considerable progress has been made in developing specific and supportive medical measures, but studies and publications have mainly concerned adult patients. Therapeutic approaches to complications of end-stage chronic liver disease and acute liver failure (e.g. refractory ascites, hepatorenal syndrome, encephalopathy, and cerebral edema) that may be applied to children are reviewed in this article.Mild-to-moderate ascites should be managed by modest salt restriction and oral diuretic therapy in the first instance. Large volume paracentesis associated with colloid volume expansion and diuretic therapy may be effective for acute relief. Treatment of hepatorenal syndrome type 1 with vasopressin analogs (terlipressin) is recommended prior to liver transplantation in order to improve renal function. Prevention and treatment of chronic hepatic encephalopathy are directed primarily at controlling the events that may precipitate hepatic encephalopathy and at reducing ammonia generation and increasing its detoxification or removal. In addition to reduction of gut ammonia production using non-absorbable disaccharides such as lactulose and/or antibacterials such as neomycin, sodium benzoate may be used on a long-term basis to prevent, stabilize, or improve hepatic encephalopathy. The management of hepatic encephalopathy in acute liver failure is considerably more unsatisfactory; treatment is aimed at preventing brain edema and intracranial hypertension. Extracorporeal liver support devices are now used commonly in critically ill children with acute renal failure, advanced hepatic encephalopathy, cerebral edema, intracranial hypertension, and severe coagulopathy. Continuous renal replacement therapy could potentially help support patients until liver transplantation is performed or liver regeneration occurs. The Molecular Adsorbent Recirculating System (MARS or albumin dialysis) is the liver support system most frequently used worldwide in adults and appears to offer distinct advantages over hepatocyte-based systems. There are no specific medical therapies or devices that can correct all of the functions of the liver. Apart from a few metabolic diseases presenting with severe liver dysfunction for which specific medical therapies may preclude the need for liver transplantation, liver transplantation still remains the only definitive therapy in most instances of end-stage chronic liver disease and acute liver failure. Future research should focus on gaining a better understanding of the mechanisms responsible for liver cell death and liver regeneration, as well as developments in hepatocyte transplantation and liver-directed gene therapy.

Molecular adsorbent recirculating system in patients with early allograft dysfunction after liver transplantation: a pilot study

Early allograft dysfunction (EAD) after orthotopic liver transplantation (OLT) causes marked morbidity and mortality. We conducted a prospective pilot study to assess the safety and efficacy of molecular adsorbent recirculating system (MARS) in treatment of EAD after OLT. Twelve consecutive adult liver allograft recipients with a median age of 48 years, 9 of whom were male, were prospectively included and supported with MARS. EAD was defined as the presence of at least 2 of the following: serum bilirubin >10 mg/dL, prothrombin time <40%, aspartate aminotransferase or alanine transferase >1,000 U/L, and plasma disappearance rate of indocyanine green (PDR(ICG)) <10% per minute within 72 hours after reperfusion. One-year patient and graft survival was 66%. There was a significant decrease in serum bilirubin (P = 0.002), serum creatinine (P = 0.006), and aspartate aminotransferase (P = 0.005) and a significant increase in PDR(ICG) (P = 0.007) after MARS treatment. Prothrombin time, albumin level, and platelet count remained stable. Sustained improvement of renal and neurological function and of mean arterial pressure were observed. No MARS-related adverse effects occurred. MARS treatment provides a safe approach to the treatment of EAD after OLT. On the basis of this pilot study, a multicenter randomized clinical trial that uses MARS treatment in EAD after OLT has been initiated.

Advances in critical care management of hepatic failure and insufficiency

BACKGROUND

Chronic liver disease is becoming an increasingly frequent diagnosis for patients in the intensive care setting with such diagnoses as symptomatic ascites, spontaneous bacterial peritonitis, hepatorenal syndrome, or fulminant hepatic failure.

OBJECTIVE

To review frequent diagnoses for patients with chronic liver disease admitted to the intensive care unit and discuss current concepts in management and investigational modalities.

RESULTS

Patients with new-onset ascites in the intensive care setting should undergo immediate ultrasound to rule out acute thrombosis. A transjugular intrahepatic portosystemic shunt is indicated when control of the refractory ascites or hepatic hydrothorax is required. In patients with hepatorenal syndrome, hemodialysis can be used as a bridge to liver transplantation. Otherwise, hepatorenal syndrome carries a high mortality. When hepatic encephalopathy is present, a precipitating cause should be sought and treated, if identified. Although bioartificial support systems are under active investigation, standard treatment for hepatic encephalopathy is lactulose and alteration of gut flora. Patients with fulminant hepatic failure should be stabilized and transferred to the intensive care unit of a liver transplant center and supported with appropriate airway management, close neurologic evaluation, glucose monitoring, and correction of coagulopathy when there is overt bleeding or an invasive procedure is planned. Intracranial pressure monitoring is recommended to maintain an adequate cerebral perfusion pressure of >60 mm Hg.

CONCLUSION

Review of the literature demonstrates that certain critically ill patients with chronic liver disease may benefit from invasive modalities such as transjugular intrahepatic portosystemic shunting, hemodialysis, and in some cases, liver transplantation, which may be offered only at tertiary care centers.

Molecular adsorbent recirculating system dialysis in patients with acute liver failure who are assessed for liver transplantation

OBJECTIVE

To assess the usefulness of dialysis with the molecular adsorbent recirculating system (MARS) in patients with acute liver failure who fulfil criteria for liver transplantation.

DESIGN

Observational cohort study.

SETTING

ICU at a liver transplantation centre.

PATIENTS

Twenty-two patients (23 episodes) received MARS dialysis. They were either listed for LT (n=14), delayed (n=1), or not listed (contra-indication, n=7).

INTERVENTIONS

A total of 56 MARS treatments (median per patient 2; mean duration 7.6+/-2.6h) were performed on haemodialysis.

MEASUREMENTS AND RESULTS

Clinical and biological variables were assessed before and 24[Symbol: see text]h after MARS therapy. The rate of recovery of liver function without transplantation was compared with an expected rate and survival was analysed. Following MARS dialysis, we observed an improvement in the grade of hepatic encephalopathy (P=0.02) and the Glasgow coma score (P=0.02), a decrease in conjugated bilirubin (P=0.05) and INR (P=0.006), and an increase in prothrombin index (P=0.005). Overall, liver function improved in seven patients (32%): four listed patients in whom transplantation could be avoided and three patients among those not listed due to contra-indications. The transplant-free recovery rate in listed patients was 29% (vs. expected 9%, P=0.036). Listed patients (n=14) had a higher 30-day survival rate [86% (12/14) vs 38% (3/8), P=0.05] and a higher long-term survival rate (P=0.02).

CONCLUSIONS

A statistically significant improvement of liver function was observed after MARS therapy. Transplant-free recovery was more frequent than expected. The apparent benefit of MARS dialysis to treat acute liver failure needs to be confirmed by a controlled study.

Therapy insight: Management of hepatorenal syndrome

Hepatorenal syndrome (HRS), a feared complication of advanced cirrhosis, is characterized by functional renal failure, secondary to renal vasoconstriction in the absence of underlying kidney pathology. Extreme underfilling of the arterial circulation, caused by arterial vasodilation of the splanchnic circulation, activates vasoconstrictor systems, which lead to intense renal vasoconstriction and HRS. Factors predictive for the development of HRS include intense urinary sodium retention, dilutional hyponatremia, low blood pressure, decreased cardiac output, and increased activity of systemic vasoconstrictors. The prognosis for patients with HRS is extremely poor, especially for those with the acute, progressive (type 1) form. Liver transplantation is the best treatment for suitable candidates and should always be the management option considered first. Pharmacologic therapies are aimed at improving renal function to enable patients to survive until transplantation is possible. These therapies are based on plasma expansion with albumin, combined with the use of either vasopressin analogs or alpha-adrenergic agonists. Other nonpharmacologic therapies, such as transjugular intrahepatic portosystemic shunts and albumin dialysis show promise, but experience with these treatments is limited. For prevention of HRS, albumin infusion is recommended in patients with spontaneous bacterial peritonitis, and pentoxifylline treatment is recommended in patients with acute alcoholic hepatitis.

Molecular adsorbent recirculating system (MARS) application in liver failure: clinical and hemodepurative results in 22 patients

PURPOSE

Acute liver failure (ALF) and acute on chronic liver failure (ACLF) still show a poor prognosis. MARS was used in 22 patients with ALF or ACLF to prolong patient survival for liver function recovery or as a bridge to transplantation.

DESIGN

Evaluation of depurative efficiency, biocompatibility, hemodynamics, encephalopathy (HE) and clinical outcome.

PROCEDURES

During 71 five-hour sessions we evaluated (0', 60', 120', 180', 240', 300'): bilirubin, ammonia, cholic acid (CCA), chenodeoxycholic acid (CCDCA), leukocytes, platelets, hemoglobin and mean arterial pressure (MAP). Serum creatinine, electrolytes, cardiac output, cardiac index (bioimpedence) and HE (West Haven Criteria score) were evaluated at 0' and 300'. STATISTICAL METHODS AND OUTCOME MEASURES: Student's t-test for pre- vs. end-session values was used. For bilirubin and ammonia the correlation test was made between pre- and end-session values and between pre-session values and removal rates (RRS).

MAIN FINDINGS

Survival was 90.9% at 7 days, 40.9% at 30 days. Pre- vs. end-session: bilirubin from 37.2 +/- 12.5 mg/dL to 24.9 +/- 8.9 mg/dL (p < 0.01), ammonia from 88.0 +/- 60.4 micromol/L to 43.6 +/- 32.9 micromol/L (p < 0.01), CCA from 42.8 +/- 21.0 micromol/L 18.2 +/- 9.8 micromol/L (p < 0.01), CCDCA from 26.3 +/- 6.3 micromol/L to 15.7+/-7.6 micromol/L (p<0.01). The correlation test between pre-session values of bilirubin and ammonia vs. RR S was respectively 0.32 (p = 0.01) and 0.30 (p = 0.04). Leukocytes, platelets and hemoglobin remained stable. MAP increased from 82.0 +/- 12.0 mmHg to 87.0 +/- 13.0 mmHg (p < 0.05), West Haven Criteria score decreased from 2.7 +/- 0.7 to 0.7 +/- 0.7 (p < 0.001).

CONCLUSION

MARS treatment led in all patients to an improvement of clinical, hemodynamic and neurological conditions, with significant reduction in the hepatic toxins blood level. Treatment biocompatibility and tolerance were satisfactory.

Molecular adsorbent recirculating system treatment for patients with liver failure: the Hong Kong experience

BACKGROUND

The molecular adsorbent recirculating system (MARS) is an extracorporeal liver dialysis system that allows selective removal of bilirubin and other albumin-bound toxins. We reported here our experience with the use of this technique for management of liver failure at Queen Mary Hospital, Hong Kong.

METHODS

From December 2002 to 2004, a total of 74 MARS sessions were performed on 22 patients. The cause of liver failure included acute liver failure (n = 2), acute on chronic liver failure (n = 12), posthepatectomy liver failure (n = 4), and posttransplantation allograft failure (n = 4).

RESULTS

MARS treatment showed significant reduction in total bilirubin level, serum ammonia level and blood urea, and nitrogen (P < 0.001 for all three parameters). Five patients (22.7%) were able to bridge to transplantation and one patient (4.5%) made a spontaneous recovery. The 30-day mortality rate was 72.7%.

CONCLUSIONS

Our results indicated that MARS can effectively improve serum biochemistry and is suitable for temporarily supporting patients with liver failure where transplantation is not immediately available. There is, however, no clear evidence showing that MARS can increase survival, improve the chance of transplantation or assist liver regeneration. Future studies in the form of randomized-controlled trials are crucial to characterize the true potential of this treatment.