l-ornithine-l-aspartate for hepatic encephalopathy in patients with cirrhosis: a meta-analysis of randomized controlled trials

Vigilance and wake EEG architecture in simulated hyperammonaemia: a pilot study on the effects of L-Ornithine-L-Aspartate (LOLA) and caffeine

Hyperammonaemia/mild hepatic encephalopathy (HE) can be simulated by the oral administration of a so-called amino acid challenge (AAC). This study sought to assess the effects of the AAC alone and in combination with either ammonia-lowering [L-ornithine-L-aspartate (LOLA)] or vigilance-enhancing medication (caffeine). Six patients with cirrhosis (5 males; 61.3 ± 9.2 years; 5 Child A, 1 Child B) and six healthy volunteers (5 males; 49.8 ± 10.6 years) were studied between 08:00 and 19:00 on Monday of three consecutive weeks. The following indices were obtained: hourly capillary ammonia, hourly subjective sleepiness, paper & pencil/computerized psychometry and wake electroencephalography (EEG) at 12:00, i.e. at the time of the maximum expected effect of the AAC.

RESULTS

On average, patients had worse neuropsychological performance and slower EEG than healthy volunteers in all conditions but differences did not reach significance. In healthy volunteers, the post-AAC increase in capillary ammonia levels was contained by both the administration of LOLA and of caffeine (significant differences between 10:00 and 14:00 h). The administration of caffeine also resulted in a reduction in subjective sleepiness and in the amplitude of the EEG on several frontal/temporal-occipital sites (p < 0.05; paired t-test). Changes in ammonia levels, subjective sleepiness and the EEG in the three conditions were less obvious in patients. In conclusion, both LOLA and caffeine contained the AAC-induced increase in capillary ammonia, especially in healthy volunteers. Caffeine also counteracted the AAC effects on sleepiness/EEG amplitude. The association of ammonia-lowering and vigilance-enhancing medication in the management of HE is worthy of further study.

Management of Neurologic Manifestations in Patients with Liver Disease

OPINION STATEMENT

Liver disease, both in its acute and chronic forms, can be associated with a wide spectrum of neurologic manifestations, both central and peripheral, ranging in severity from subclinical changes to neurocritical conditions. Neurologists are frequently consulted to participate in their management. In this review, we present an overview of management strategies for patients with hepatic disease whose clinical course is complicated by neurologic manifestations. Type A hepatic encephalopathy (HE), which occurs in acute liver failure, is a neurologic emergency, and multiple measures should be taken to prevent and treat cerebral edema. In Type C HE, which occurs in chronic liver disease, management should be aimed at correcting precipitant factors and hyperammonemia. There is an increasing spectrum of drug treatments available to minimize ammonia toxicity. Acquired hepatocerebral degeneration is a rare complication of the chronic form of HE, with typical clinical and brain MRI findings, whose most effective treatment is liver transplantation. Epilepsy is frequent and of multifactorial cause in patients with hepatic disease, and careful considerations should be made regarding choice of the appropriate anti-epileptic drugs. Several mechanisms increase the risk of stroke in hepatic disease, but many of the drugs used to treat and prevent stroke are contraindicated in severe hepatic failure. Hepatitis C infection increases the risk of ischemic stroke. Hemorrhagic stroke is more frequent in patients with liver disease of alcoholic etiology. Viral hepatitis is associated with a wide range of immune-mediated complications, mostly in the peripheral nervous system, which respond to different types of immunomodulatory treatment. Several drugs used to treat hepatic disease, such as the classical and the new direct-acting antivirals, may have neurologic complications which in some cases preclude its continued use.

Treatment of Overt Hepatic Encephalopathy

Hepatic encephalopathy (HE) is defined by an altered mental status in the setting of portosystemic shunting, with or without cirrhosis. The basis of HE is probably multi-factorial, but increased ammonia delivery to the brain is thought to play a pivotal role. Medical therapies have typically focused on reducing blood ammonia concentrations. These measures are moderately effective, but further improvements will require identification of new therapeutic targets. Two medications, lactulose and rifaximin, are currently approved for the treatment of HE in the USA - new compounds are available off-label, and are in clinical trials. The presence of HE is associated with a higher risk of death in cirrhotic patients. Liver transplantation typically cures HE, but HE does not increase the MELD score, and therefore does not contribute to the likelihood of liver transplantation.

Diagnosis and Treatment of Low-Grade Hepatic Encephalopathy

Minimal hepatic encephalopathy (mHE) is common among patients with cirrhotic liver disease and causes significant morbidity and mortality. It may present as cognitive impairment, behavioural changes and, less frequently, with neurological symptoms which make diagnosis of the disease challenging. A history of falls and accidents may also be suggestive of mHE. Diagnosis primarily relies on at least two positive psychometric tests of which the psychometric hepatic encephalopathy score (PHES) is essential. Alternatively, PHES and an electroencephalogram may be used to establish a diagnosis. Biochemical markers of encephalopathy currently have no role in the diagnosis of mHE. Treatment is not always advocated for a diagnosis of mHE but is dependent on the degree of impairment caused by the symptoms. After treatment of other metabolic abnormalities and co-morbidities associated with cirrhosis, more specific treatment for mHE largely relies on therapies used to lower ammonia levels. Laxatives and rifaximin are commonly used in treatment and work through decreasing ammonia absorption from the gut. Other therapies, such as BCAA, LOLA, L-carnitine and phenylbutyrate, modify responses to ammonia as well as enhancing metabolism and excretion. mHE resulting from spontaneous portosystemic shunts or transhepatic intraportal systemic shunts may require ablation or reduction of the shunt. Early detection and appropriate treatment of mHE is important to prevent significant cognitive impairments and progression to overt HE.

Progress in treatment of hepatic encephalopathy

Hepatic encephalopathy (HE) is a common complication of severe liver disease and a common cause of mortality. Clinical features range from clinically imperceptible symptoms in minimal HE which require neuropsychological testing to identify, to abnormal behavior, mental deterioration, and even coma or death. It is a reversible progressive neuropsychiatric disorder that is associated with a decrease in quality of life and an increase in rate of hospitalization and consequent costs because patients are at risk for recurrence. Unfortunately, the prevalence of HE continues to rise for several reasons. For one, patients with viral hepatitis are now developing cirrhosis. Additionally, we are currently in the midst of a global obesity epidemic, which fuels the metabolic syndrome and nonalcoholic fatty liver disease, and these patients are now presenting in larger numbers with complications of chronic liver disease such as HE. The high morbidity and mortality combined with the costs underline the importance to search the effective treatment for HE. This article reviews the progress in the treatment of HE.

Systematic review with network meta-analysis: the comparative effectiveness and safety of interventions in patients with overt hepatic encephalopathy

BACKGROUND

Interventional treatment for overt hepatic encephalopathy (OHE), includes non-absorbable disaccharides, neomycin, rifaximin, L-ornithine-L-aspartate and branched chain amino acids (BCAA). However, the optimum regimen remains inconclusive.

AIM

To compare interventions in terms of patients' adverse events and major clinical outcomes.

METHODS

Literature search of PubMed, Embase, Scopus, and Cochrane Library studies published up to July 31 2014. RCTs of above interventions in OHE patients were included. Network meta-analysis combined direct and indirect evidence to estimate odds ratios (ORs) and mean difference (MD) between treatments and the probabilities of ranking for treatment based on clinical outcomes.

RESULTS

Twenty eligible RCTs were included. When compared with observation, only L-ornithine-L-aspartate (OR 3.71, P < 0.001) and BCAA (OR 3.37, P < 0.001) improved clinical efficacy significantly. However, when L-ornithine-L-aspartate was compared with BCAA, non-absorbable disaccharides and neomycin, there was a trend suggesting that L-ornithine-L-aspartate may be the most effective intervention with respect to clinical improvement (OR 1.10), rifaximin (OR 1.31), non-absorbable disaccharides (OR 2.75), neomycin (OR 2.22). In addition, L-ornithine-L-aspartate (MD -20.18, 95% CI -40.12 to -0.27) provided a significant reduction in blood ammonia concentration compared with observation. Neomycin appeared to be associated with more adverse events in comparison with non-absorbable disaccharides (OR 10.15), rifaximin (OR 17.31), L-ornithine-L-aspartate (OR 3.16) or BCAA (OR 7.69).

CONCLUSIONS

L-ornithine-L-aspartate treatment may show a trend in superiority for clinical efficacy among standard interventions for OHE. Rifaximin shows the greatest reduction in blood ammonia concentration, and treatment with neomycin demonstrates a higher probability in causing adverse effects among the five compared interventions.

Management of overt hepatic encephalopathy

Hepatic encephalopathy (HE) is an important complication of cirrhosis with significant morbidity and mortality. Management of HE primarily involves avoidance of precipitating factors and administration of various ammonia-lowering therapies such as non-absorbable disaccharides, antimicrobial agents like rifaximin and l-ornithine l-aspartate. The non-absorbable disaccharides which include lactulose and lactitol are considered the first-line therapy for the treatment of HE and in primary and secondary prophylaxis of HE. Lactitol is comparable to lactulose in the treatment of HE with fewer side effects. Rifaximin is effective in treatment of HE and recent systemic reviews found it comparable to disaccharides and is effective in secondary prophylaxis of HE. Many agents like l-ornithine l-aspartate, probiotics, zinc, sodium benzoate have been tried either alone or in combination with lactulose for the treatment of HE. Combination therapy of disaccharides either with rifaximin, l-ornithine l-aspartate, probiotics for the treatment of HE needs further validation in large studies.

Management of covert hepatic encephalopathy

Hepatic encephalopathy is a reversible progressive neuropsychiatric disorder that encompasses a wide clinical spectrum. Covert hepatic encephalopathy is defined as patients with minimal hepatic encephalopathy and Grade I encephalopathy by West-Haven Criteria. Terminology such as "sub-clinical", "latent", and "minimal" appear to trivialize the disease and have been replaced by the term covert. The lack of clinical signs means that covert hepatic encephalopathy is rarely recognized or treated outside of clinical trials with options for therapy based on patients with episodic hepatic encephalopathy. This review discusses the current available options for therapy in covert hepatic encephalopathy and focuses on non-absorbable disacharides (lactulose or lactitol), antibiotics (rifaximin), probiotics/synbiotics and l-ornithine-l-aspartate.

Pharmacotherapy for hyperammonemia

INTRODUCTION

Hepatic encephalopathy (HE) is a serious neuropsychiatric complication that is seen in patients with liver failure. The pathogenesis of HE is not entirely understood, but several hypotheses have emerged and persisted during the years. Despite the many prevalent hypotheses, most of the existing evidence point to ammonia as the main culprit behind primary and secondary symptoms making it the center of potential therapeutic options for the treatment of HE. Most treatments of hyperammonemia target the organs and metabolic processes involved in ammonia detoxification.

AREAS COVERED

This article provides a review of the current targets of therapy as well as the drugs used for hyperammonemia treatment.

EXPERT OPINION

Lactulose and rifaximin have a proven role as measures to use for secondary prophylaxis and are the mainstay of current therapy. The use of molecular adsorbent recirculating system in patients with severe HE has been proven to be efficacious, but through mechanisms that appear to be independent of ammonia. The main challenge that faces the further development of treatments for HE is finding appropriate end points, and the next step would be to provide evidence of the effectiveness of established treatments and define the role of emerging new treatments.

Oral l-ornithine-l-aspartate in minimal hepatic encephalopathy: A randomized, double-blind, placebo-controlled trial

AIM

Evaluate efficacy/safety of oral l-ornithine-l-aspartate (LOLA) in controlling minimal hepatic encephalopathy (MHE).

METHODS

Consecutive cirrhotic outpatients with MHE (defined by psychometric number connection tests A/B [NCT-A/B] and digit symbol substitution test [DSST] score of >2 standard deviations) were randomized to a 60-day oral LOLA (5 g t.i.d) or placebo group. Critical flicker frequency test (CFF), quantitative electroencephalogram (qEEG), arterial ammonia (NH3), Beck's anxiety-depression forms and liver disease quality of life (LD-QOL) were assessed. Patients were followed for 6 months after the end of the study to assess LOLA prophylactic role on overt hepatic encephalopathy (OHE).

RESULTS

Sixty-four patients were included, 63 (98.4%) with MHE. In six of these patients, CFT was less than 39 Hz (9.52%); NH3 was increased in 32 (50.8%); 25% had abnormal qEEG. Age, sex, scholarship, Child-Pugh (CP), Model for End-Stage Liver Disease, NCT-A/B, DSST, CFF and NH3 were similar in both groups at the baseline. LOLA led to a significant improvement in NCT-B age-controlled z-score (3.4 ± 3.4 vs 1.5 ± 2.3, P = 0.01) and CFF (42.2 ± 5.8 vs 45.2 ± 5.8, P = 0.02), comparing the first and the last visit, but there were no differences between LOLA and placebo regarding the whole psychometric battery, CFF, LD-QOL and Beck's forms. No serious adverse effects occurred. Patients taking LOLA had less episodes of OHE at 6 months (5% vs 37.9%, P = 0.016), as they have significant improvement on liver function assessed by CP (P < 0.001).

CONCLUSION

A 60-day oral LOLA course was not better than placebo in treating MHE, but was useful in preventing further episodes of OHE.

Randomised clinical trial: L-ornithine-L-aspartate reduces significantly the increase of venous ammonia concentration after TIPSS

BACKGROUND

Use of TIPSS is associated with increases in ammonia concentration and hepatic encephalopathy (HE) risk. L-ornithine-L-aspartate (LOLA) is effective in reducing ammonia concentration.

AIM

To evaluate the effects of LOLA on venous ammonia concentration after TIPSS.

METHODS

The included patients were randomised to receive LOLA or no-LOLA treatment for 7 days. Fasting and post-prandial venous ammonia levels were the primary outcomes. Psychometric performance, post-TIPSS HE, and liver and renal function were assessed as secondary outcomes.

RESULTS

Of 133 cirrhotic patients who received successful TIPSS between November 2011 and June 2012, 40 met the inclusion criteria and were randomised to the LOLA (n = 21) or control (n = 19) groups. Change in fasting ammonia significantly favoured the LOLA group at days 4 (P = 0.001) and 7 (P = 0.003). Changes in post-prandial ammonia concentration significantly favoured the LOLA group at days 1, 4 and 7 as well. During the study period, patients in the LOLA group had better improvement in psychometric tests than those in the control group. Overt HE during treatment was observed in one patient in the LOLA group and three patients in the control group (P = 0.331). There were no differences in complications, adverse events or mortality between the two groups.

CONCLUSIONS

Prophylactic use of LOLA infusion after TIPSS is safe and effective in significantly reducing the increase of venous ammonia concentration, and can benefit the patient's mental status as well.

Liver cirrhosis

Cirrhosis is an increasing cause of morbidity and mortality in more developed countries, being the 14th most common cause of death worldwide but fourth in central Europe. Increasingly, cirrhosis has been seen to be not a single disease entity, but one that can be subclassified into distinct clinical prognostic stages, with 1-year mortality ranging from 1% to 57% depending on the stage. We review the current understanding of cirrhosis as a dynamic process and outline current therapeutic options for prevention and treatment of complications of cirrhosis, on the basis of the subclassification in clinical stages. The new concept in management of patients with cirrhosis should be prevention and early intervention to stabilise disease progression and to avoid or delay clinical decompensation and the need for liver transplantation. The challenge in the 21st century is to prevent the need for liver transplantation in as many patients with cirrhosis as possible.

Treatment options for covert hepatic encephalopathy

OPINION STATEMENT

The main issue with treating covert hepatic encephalopathy (HE) is to establish whether it is cost effective to reverse the neuropsychiatric abnormalities that define this mild form of HE. Until fairly recently, covert HE was rarely diagnosed, but advances in computerized psychometric testing have greatly simplified its detection. The many consequences of covert HE are now being identified, and most have been shown to be reversible with standard HE treatment. Perhaps the most enticing possibility will be the potential that standard HE therapies will postpone the onset of overt HE. This will require further evaluation with large placebo-controlled randomized trials.

Preventing cerebral oedema in acute liver failure: the case for quadruple-H therapy

Severe cerebral oedema is a life-threatening complication of acute liver failure. Hyperammonaemia and cerebral hyperaemia are major contributing factors. A multimodal approach, which incorporates hyperventilation, haemodiafiltration, hypernatraemia and hypothermia (quadruple-H therapy), may prevent or attenuate severe cerebral oedema. This approach is readily administered by critical care clinicians and is likely to be more effective than the use of single therapies. Targeting of PaCO2 in the mild hyperventilation range, as seen in acute liver failure patients before intubation, aims to minimise hyperaemic cerebral oedema. Haemodiafiltration aims to achieve the rapid control of elevated blood ammonia concentrations by its removal and to reduce production via the lowering of core temperature. The administration of concentrated saline increases serum tonicity and further reduces cerebral swelling. In addition, the pathologically increased cerebral blood-flow is further attenuated by therapeutic hypothermia. The combination of all four treatments in a multimodal approach may be a safe and effective means of attenuating or treating the cerebral oedema of acute liver failure and preventing death from neurological complications.

Duplicates in systematic reviews: A critical, but often neglected issue

The number of systematic reviews is gradually increasing over time. Also, the methods to perform a systematic review are being improved. However, little attention has been paid for the issue regarding how to find duplicates in systematic reviews. On the basis of the survey and systematic reviews by our team and others, we review the prevalence, significance and classification of duplicates and the method to find duplicates in a systematic review. Notably, although a preliminary method to find duplicates is established, its usefulness and convenience need to be further confirmed.