A Long-Term Study of Changes in the Volume of Brain Ventricles and White Matter Lesions After Successful Liver Transplantation

Cognitive function, self-management, and outcomes among liver transplant recipients: LivCog, a multicenter, prospective study

Liver transplantation is a life-saving option for decompensated cirrhosis. Liver transplant recipients require advanced self-management skills, intact cognitive skills, and care partner support to improve long-term outcomes. Gaps remain in understanding post-liver transplant cognitive and health trajectories, and patient factors such as self-management skills, care partner support, and sleep. Our aims are to (1) assess pre-liver transplant to post-liver transplant cognitive trajectories and identify risk factors for persistent cognitive impairment; (2) evaluate associations between cognitive function and self-management skills, health behaviors, functional health status, and post-transplant outcomes; and (3) investigate potential mediators and moderators of associations between cognitive function and post-liver transplant outcomes. LivCog is a longitudinal, prospective observational study that will enroll 450 adult liver transplant recipients and their caregivers/care partners. The duration of the study is 5 years with 24 additional months of patient follow-up. Data will be collected from participants at 1, 3, 12, and 24 months post-transplant. Limited pre-liver transplant data will also be collected from waitlisted candidates. Data collection methods include interviews, surveys, cognitive assessments, and actigraphy/sleep diary measures. Patient measurements include sociodemographic characteristics, pretransplant health status, cognitive function, physical function, perioperative measures, medical history, transplant history, self-management skills, patient-reported outcomes, health behaviors, and clinical outcomes. Caregiver measures assess sociodemographic variables, health literacy, health care navigation skills, self-efficacy, care partner preparedness, nature and intensity of care, care partner burden, and community participation. By elucidating various health trajectories from pre-liver transplant to 2 years post-liver transplant, LivCog will be able to better characterize recipients at higher risk of cognitive impairment and compromised self-management. Findings will inform interventions targeting health behaviors, self-management, and caregiver supports to optimize outcomes.

Post-liver transplantation patient experience

Given improvements in post-transplant patient and graft survival, there is a growing need to focus on patient experience and health-related quality of life (HRQOL). Though liver transplantation can be life-saving, it can also be associated with significant morbidity and complications. Patient HRQOL improves after transplantation, but it may not improve to that of age-matched cohorts. Understanding patient experience and the factors that contribute to it, including physical and psychological health, immunosuppression and medication adherence, return to employment or school, financial burden, and expectations, helps when thinking creatively about potential interventions to improve HRQOL.

Characteristics of stroke after liver and kidney transplantation

Background

The mechanism and characteristics of a post-transplantation stroke may differ between liver (LT) and kidney transplantation (KT), as the associated comorbidities and peri-surgical conditions are different. Herein, we investigated the characteristics and etiologies of stroke occurring after LT and KT.

Methods

Consecutive patients who received LT or KT between January 2005 to December 2020 who were diagnosed with ischemic or hemorrhagic stroke after transplantation were enrolled. Ischemic strokes were further classified according to the etiologies. The characteristics of stroke, including in-hospital stroke, perioperative stroke, stroke etiology, and timing of stroke, were compared between the LT and KT groups.

Results

There were 105 (1.8%) and 58 (1.3%) post-transplantation stroke patients in 5,950 LT and 4,475 KT recipients, respectively. Diabetes, hypertension, and coronary arterial disease were less frequent in the LT than the KT group. In-hospital and perioperative strokes were more common in LT than in the KT group (LT, 57.9%; KT, 39.7%; p = 0.03, and LT, 43.9%; KT, 27.6%; p = 0.04, respectively). Hemorrhagic strokes were also more common in the LT group (LT, 25.2%; KT, 8.6%; p = 0.01). Analysis of ischemic stroke etiology did not reveal significant difference between the two groups; undetermined etiology was the most common, followed by small vessel occlusion and cardioembolism. The 3-month mortality was similar between the two groups (both LT and KT, 10.3%) and was independently associated with in-hospital stroke and elevated C-reactive protein.

Conclusions

In-hospital, perioperative, and hemorrhagic strokes were more common in the LT group than in the KT group. Ischemic stroke subtypes did not differ significantly between the two groups and undetermined etiology was the most common cause of ischemic stroke in both groups. High mortality after stroke was noted in transplantation patients and was associated with in-hospital stroke.

Redefining Success After Liver Transplantation: From Mortality Toward Function and Fulfillment

Liver transplantation (LT), the only cure for end-stage liver disease, is a lifesaving, costly, and limited resource. LT recipients (LTRs) are aging with an increasing burden of medical comorbidities. Patient and graft survival rates exceed 70% at 5 years; however, patient-centered health outcomes beyond survival have received relatively little attention. LTRs must have strong self-management skills to navigate health systems, adhere to clinical monitoring, and take complex, multidrug regimens. All of these tasks require formidable cognitive abilities for active learning and problem solving. Yet, LTRs are at higher risk for impaired cognition as a result of the high prevalence of pretransplant hepatic encephalopathy, multiple chronic conditions, alcohol use, physical frailty, sarcopenia, and older age. Cognitive impairment after transplant may persist and has been causally linked to poor self-management skills, worse physical function, and inferior health outcomes in other health care settings, yet its impact after LT is largely unknown. There is a need to study potentially modifiable, posttransplant targets including caregiver support, physical activity, sleep, and treatment adherence to inform future health system responses to promote the long-term health and well-being of LTRs. Prospective, longitudinal data collection that encompasses key sociodemographic, cognitive-behavioral, psychosocial, and medical factors is needed to improve risk prediction and better inform patient and caregiver expectations. Interventions with proactive monitoring, reducing medical complexity, and improved care coordination can be tailored to optimize posttransplant care. We propose a research agenda focused on understudied, potentially modifiable risk factors to improve the long-term health of LTRs. Our conceptual model accounts for cognitive function, caregiver and patient self-management skills, health behaviors, and patient-centered outcomes beyond mortality. We propose actionable health-system, patient, and caregiver-directed interventions to fill knowledge gaps and improve outcomes.

Hepatic Encephalopathy and Liver Transplantation: The Past, Present, and Future Toward Equitable Access

Cirrhosis is a debilitating chronic disease with high morbidity and mortality, with the only real cure being liver transplantation (LT). Currently, we allocate organs for transplantation based on the Model for End-Stage Liver Disease-Sodium (MELD-Na) score that does not account for hepatic encephalopathy (HE). HE affects patients, families, and the health care system because of high rates of recurrence and major readmission burden. Moreover, HE casts a long shadow even after LT. Accounting for HE and incorporating it into the current allocation system has many proponents, but the framework to do this is currently lacking because of differences in consensus or in operationalization parameters. We review the latest evidence of the burden of HE, management of HE before and after LT, and evaluate pros and cons of several methods of diagnosing HE objectively to ensure early and equitable access to LT in this underserved population.

Hepatic Encephalopathy: From Metabolic to Neurodegenerative

Hepatic encephalopathy (HE) is a neuropsychiatric syndrome of both acute and chronic liver disease. As a metabolic disorder, HE is considered to be reversible and therefore is expected to resolve following the replacement of the diseased liver with a healthy liver. However, persisting neurological complications are observed in up to 47% of transplanted patients. Several retrospective studies have shown that patients with a history of HE, particularly overt-HE, had persistent neurological complications even after liver transplantation (LT). These enduring neurological conditions significantly affect patient's quality of life and continue to add to the economic burden of chronic liver disease on health care systems. This review discusses the journey of the brain through the progression of liver disease, entering the invasive surgical procedure of LT and the conditions associated with the post-transplant period. In particular, it will discuss the vulnerability of the HE brain to peri-operative factors and post-LT conditions which may explain non-resolved neurological impairment following LT. In addition, the review will provide evidence; (i) supporting overt-HE impacts on neurological complications post-LT; (ii) that overt-HE leads to permanent neuronal injury and (iii) the pathophysiological role of ammonia toxicity on astrocyte and neuronal injury/damage. Together, these findings will provide new insights on the underlying mechanisms leading to neurological complications post-LT.

Spotlight on Impactful Research: Long-Term Calcineurin Inhibitor Therapy and Brain Function in Patients After Liver Transplantation

http://aasldpubs.onlinelibrary.wiley.com/hub/journal/10.1002/(ISSN)2046-2484/video/15-4-reading-cheung a video presentation of this article - http://aasldpubs.onlinelibrary.wiley.com/hub/journal/10.1002/(ISSN)2046-2484/video/15-4-interview-cheung an interview with the author https://www.wileyhealthlearning.com/Activity/7088571/disclaimerspopup.aspx questions and earn CME.

Cognitive Function in Liver Transplantation

PURPOSE OF REVIEW

Liver transplantation (LT) remains the only way to cure patients with severe liver diseases. Important questions about neurological sequelae and quality of life after LT have emerged. In this review, we discuss the neurocognitive changes associated with LT and we conclude with recommendations in this regard for patients, caregivers, and physicians.

RECENT FINDINGS

Compared with other solid organ recipients, LT patients tend to have a higher incidence (up to 30%) of neurological complications post-LT. Even in absence of previous episodes of hepatic encephalopathy (HE), some patients display new onset of neurological symptoms post-LT, raising the concern about the role of other factors that may have a direct impact on cognitive function.

SUMMARY

Different mechanisms have been postulated to explain these postoperative neurological symptoms. They include sequelae of HE, persistent impairment of cognitive function due to cirrhosis, or postoperative decompensation of an unknown or undiagnosed neurodegenerative disorder.

Hepatic Encephalopathy Is Reversible in the Long Term After Liver Transplantation

Cognitive dysfunction caused by hepatic encephalopathy (HE) improves within the first year after liver transplantation (LT). However, cognitive restitution seems to be incomplete in a subset of patients and after LT a new-onset cognitive decline was described. Data about the longterm development of cognitive function after liver transplantation (LT) are sparse. This prospective study analyzed whether a history of hepatic encephalopathy (HE) before LT had an impact on the longterm outcome of cognitive function after LT and if patients who underwent LT 5 years earlier showed worse cognitive function than healthy controls. The cognitive function of 34 patients was assessed before LT and at 1 year and 5 years after LT by psychometric tests, including the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) and the portosystemic encephalopathy syndrome test, which provides the psychometric hepatic encephalopathy score (PHES). Furthermore, patients completed surveys to assess health-related quality of life (HRQOL). An 22 additional patients were included after LT. Patients were subdivided by having a history of HE before LT. The control group consisted of 55 healthy patients adjusted for age and education. Before LT, patients performed significantly worse than controls in the psychometric tests: RBANS Total Scale (TS), mean ± standard deviation (SD), 92.6 ± 13.3 versus 99.9 ± 12.0, P = 0.01; and PHES, median (interquartile range [IQR]), 0 (-3 to 1) versus 1 (0-2), P < 0.001. At 1 year after LT, patients with a history of HE still showed cognitive impairment compared with controls: RBANS TS, mean ± SD, 89.8 ± 15.1 versus 99.9 ± 12.0, P < 0.01; and PHES, median (IQR), 0 (-2 to 1.25) versus 1 (0-2), P = 0.03. At 5 years after LT, patients with and without a history of HE showed normal cognitive function and improved HRQOL. In conclusion, HE-associated cognitive impairment seems to be reversible within 5 years after LT.

Quantitative magnetic resonance imaging indicates brain tissue alterations in patients after liver transplantation

PURPOSE

To investigate cerebral microstructural alterations in patients treated with calcineurin inhibitors (CNI) after orthotopic liver transplantation (OLT) using quantitative magnetic resonance imaging (qMRI) and a cross-sectional study design.

METHODS

Cerebral qMRI was performed in 85 patients in a median 10 years after OLT compared to 31 healthy controls. Patients were treated with different dosages of CNI or with a CNI-free immunosuppression (CNI-free: n = 19; CNI-low: n = 36; CNI-standard: n = 30). T2-, T2*- and T2'- relaxation times, as well as apparent diffusion coefficient (ADC) and fractional anisotropy (FA) were measured in brain gray and white matter by using the regions of interest method.

RESULTS

In comparison to controls, patients revealed significantly increased T2, T2*, T2', ADC and reduced FA, predominantly in the frontal white matter, indicating microstructural brain alterations represented by increased free water (increased T2), reduced neuronal metabolism (increased T2') and a lower degree of spatial organization of the nervous fibers (reduced FA). CNI-low and CNI-free patients showed more alterations than CNI-standard patients. Analysis of their history revealed impairment of kidney function while under standard CNI dose suggesting that these patients may be more vulnerable to toxic CNI side-effects.

CONCLUSION

Our findings suggest that the individual sensitivity to toxic side effects should be considered when choosing an appropriate immunosuppressive regimen in patients after liver transplantation.

Brain metabolic alterations in patients with long-term calcineurin inhibitor therapy after liver transplantation

BACKGROUND

Calcineurin inhibitor (CNI) neurotoxicity after liver transplantation might be due to impairment of the cerebral metabolism.

AIMS

To investigate CNI-related alterations of brain metabolite distributions and associations between cognitive function and brain metabolism in patients with long-term CNI treatment after liver transplantation.

METHODS

Eighty-two patients (19 CNI free, 34 CNI low-dose and 29 standard-dose CNI immunosuppression) 10 years after liver transplantation and 32 adjusted healthy controls underwent nonlocalised brain phosphorus magnetic resonance spectroscopy (MRS) and single voxel proton MRS in the parietal white matter to estimate brain metabolite contents. The MRS results were correlated with psychometric data assessing cognitive function.

RESULTS

Phosphorus metabolite concentrations with the exception of phosphocreatine (PCr) were reduced in patients compared to controls. Particularly, patients with low-dose CNI therapy showed a significant decrease in adenosine triphosphate (0.209 ± 0.012 vs 0.222 ± 0.010; P < 0.001) and a significant increase in PCr (0.344 ± 0.026 vs 0.321 ± 0.017; P < 0.001) compared to controls. Myo-Inositol in the CNI free group (2.719 ± 0.549 institutional unit [iu]) was significantly lower compared to controls (3.181 ± 0.425 iu; P = 0.02), patients on low-dose (3.130 ± 0.513 iu; P < 0.05) and standard-dose CNI therapy (3.207 ± 0.632 iu; P < 0.02). Glutamate and glutamine levels correlated negatively with cognitive function (Repeatable Battery for the Assessment of Neuropsychological Status Total Scale: R = -0.362, P = 0.029).

CONCLUSION

Long-term CNI therapy after liver transplantation might be associated with alterations of brain metabolites.

Neurological Complications Occurring After Liver Transplantation: Role of Risk Factors, Hepatic Encephalopathy, and Acute (on Chronic) Brain Injury

Orthotopic liver transplantation (LT) remains the only way to definitively cure patients with the most severe liver diseases. Because the survival rate is now fairly high, important questions about neurological sequelae or quality of life after LT have emerged. Indeed, LT represents a peculiar situation because up to 30% of patients present with neurological symptoms after LT compared with only 4% after cardiac transplant and 0.5% after renal transplant. These postoperative neurological symptoms have long been interpreted as sequelae of hepatic encephalopathy (HE). However, postoperative decompensation of an unknown cerebral condition due to the pathophysiology of cirrhosis or undiagnosed neurodegenerative disorders or aging constitute other possibilities that are underrecognized. Some patients who undergo LT for acute liver failure and patients with cirrhosis without episodes of HE and without any previous cerebral alteration also display post-LT neurological symptoms. This latter situation speaks in favor of a direct adverse effect of either general anesthesia, the surgical procedure, or factors related to the postoperative intensive care unit (ICU) environment. The role of inflammation, which has been described in the ICU setting, could also be a crucial determinant. In this review, we will discuss the neurological complications associated with LT, the neurocognitive complications after LT, and how to assess the LT-related neurological or neurocognitive complications. Furthermore, we will review the various hypotheses surrounding post-LT neurocognitive impairment and will conclude with recommendations for future directions.

Longterm calcineurin inhibitor therapy and brain function in patients after liver transplantation

Calcineurin inhibitors (CNIs) frequently induce neurological complications early after orthotopic liver transplantation (OLT). We hypothesize that longterm CNI therapy after OLT causes dose-dependent cognitive dysfunction and alteration of brain structure. In this study, 85 OLT patients (20 with CNI-free, 35 with CNI low-dose, and 30 with standard-dose CNI immunosuppression) underwent psychometric testing and cerebral magnetic resonance imaging approximately 10 years after OLT to assess brain function and structural brain alterations. A total of 33 healthy patients adjusted for age, sex, and education served as controls. Patients receiving CNI showed a significantly worse visuospatial/constructional ability compared with controls (P ≤ 0.04). Furthermore, patients on low-dose CNI therapy had an overall impaired cognitive function compared with controls (P = 0.01). The tacrolimus total dose and mean trough level were negatively correlated to cognitive function. CNI doses had been adjusted in 91% of the patients in the low-dose and CNI-free groups in the past due to CNI-induced kidney damage. Patients treated with CNI showed significantly more white matter hyperintensities (WMH) than patients on CNI-free immunosuppression and controls (P < 0.05). Both the mean cyclosporine A and tacrolimus trough levels correlated significantly with WMH. In conclusion, longterm CNI therapy carries a risk of cognitive dysfunction especially in patients who already showed nephrotoxic side effects indicating an increased susceptibility of these patients against toxic CNI effects. This subgroup of patients might benefit from a change to CNI-free immunosuppression. Liver Transplantation 24 56-66 2018 AASLD.

Relationship between Cerebral Microbleeds and Liver Stiffness Determined by Transient Elastography

BACKGROUND & AIMS

Liver fibrosis is a multifactorial disease that can affect the development of cerebral small vessel diseases (SVDs) including cerebral microbleeds (CMBs), leukoaraiosis, and silent infarctions. Transient elastography can accurately assess the degree of liver fibrosis by measuring liver stiffness (LS). In the present study, we investigated the association between SVDs and LS values.

METHODS

We recruited 300 participants (mean age 56 years, 170 men) who underwent a comprehensive medical health check-up between January 2011 and December 2012. Transient elastography was taken on the right lobe of the liver through intercostal space with patients lying in the dorsal decubitus position with the right arm in maximal abduction. Mild and significant fibrosis were defined as LS values >5.6 and >8.0 kPa, respectively. The presence of each SVD was determined using the FLAIR, GRE MR imaging as well as T1-, T2-weighted MR images. We tested whether the presence and burden of each type of SVD were different by LS values.

RESULTS

Of the different types of SVDs, only the presence (p = 0.001) and number of CMBs (p<0.001) were positively associated with LS values. Multivariate analysis revealed that significant fibrosis (>8.0 kPa) was an independent predictor of CMBs (odds ratio 6.079, 95% confidence interval 1.489-24.819, p = 0.012). However, leukoaraiosis and silent infarctions were not associated with LS values (all p>0.05).

CONCLUSIONS

The degree of liver fibrosis, as assessed using transient elastography, was independently associated with the presence and burden of CMBs in healthy, asymptomatic participants. Understanding the link between the brain and liver may advance future research on the pathomechanisms of CMBs.

Postoperative cognitive dysfunction after liver transplantation

OBJECTIVE

Postoperative cognitive dysfunction (POCD) in liver transplant (LT) recipients is defined as a "more than expected" postoperative deterioration in cognitive domains, including short-term and long-term memory, mood, consciousness and circadian rhythm. It is diagnosed, after exclusion of other neurological complications, by using specific neuropsychological tests that need preoperative baseline. The aim of this systematic review was to assess the prevalence of POCD after LT and to analyze patients' symptoms, type and timing of assessment used.

METHODS

PubMed, MEDLINE and The Cochrane Li-brary were searched up from January 1986 to August 2014. Study eligibility criteria are as follows: prospective and retrospective studies on human adult subjects describing prevalence of POCD and/or its sequelae after LT episodes were included.

RESULTS

Eighteen studies were identified. The timing of testing for POCD may vary between different studies and within the single study, ranging from 0.5 to 32 weeks. POCD occurs in up to 50% of LT recipient.

CONCLUSION

Future studies should be focused on detecting preoperative and intraoperative factors associated to POCD in order to carry out appropriate strategies aimed at reducing this disabling health condition. Relationship between POCD and long-term outcome needs to be investigated.

The brain in acute on chronic liver failure

Acute-on-chronic liver failure (ACLF) is a newly defined clinical entity with significant morbidity and mortality (~40-90% at 1 year dependent on need for organ support at presentation). It defines a presentation with acute severe liver injury, often with multiorgan dysfunction, on a background of previously known or unknown cirrhosis. In its severest form, it is almost indistinguishable from acute liver failure, as similarly in around 5% may rapidly progress to intracranial hypertension and cerebral oedema culminating in coma and/or death. Our understanding of such cerebral sequelae is currently limited to clinical observation, though our knowledge base is rapidly expanding since recent consensus clinical definition and guidance. Moreover, there are now animal models of ACLF and imaging modalities to better characterize events in the brain that occur with ACLF. However, as yet there has been little in the way of interventional study of this condition which are much needed. In this review we dissect existing clinical and experimental data to better characterise the manifestations of ACLF on the brain and allow for the development of targeted therapy as currently the plethora of existing interventions were designed to treat either the effects of cirrhosis or acute liver injury independently.

New-onset cognitive dysfunction impairs the quality of life in patients after liver transplantation

Patients after orthotopic liver transplantation (OLT) may show cognitive dysfunction. To date, it has not been clear whether this dysfunction is due to residual hepatic encephalopathy (HE) or new-onset cognitive disturbances. Just as little is known about the course and clinical significance. In this prospective, observational study, 50 patients on the waiting list for OLT were examined in an outpatient setting before OLT and 6 and 12 months after OLT with the Psychometric Hepatic Encephalopathy Score, the Inhibitory Control Test, and the critical flicker frequency for the diagnosis of HE; in addition, the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) was used as a tool for the measurement of global cognitive function. The Short Form 36 health survey was used to assess health-related quality of life. Twelve months after OLT, cognitive dysfunction characteristic of HE had resolved, but a secondary cognitive decline became apparent and had features different from those known with HE. Approximately 70% of the patients deteriorated in at least 1 cognitive domain of RBANS. This cognitive decline was related to neither a history of HE nor a history of alcohol abuse, but it was accompanied by a decline in the quality of life. In conclusion, OLT improves HE but is frequently followed by new-onset cognitive dysfunction, which can interfere with the quality of life.

Encephalopathy and liver transplantation

Liver transplantation (LT) candidates experience frequently episodic or persistent hepatic encephalopathy. In addition, these patients can exhibit neurological comorbidities that contribute to cognitive impairment in the pre-transplant period. Assessment of the respective contribution of hepatic encephalopathy or comorbidities in the cognitive manifestations is critical to estimate the neurological benefits of restoring liver function. Magnetic resonance imaging and spectroscopy are useful to assess the impact of liver failure or comorbidities. This assessment is critical to decide liver transplant in difficult cases. In the early postoperative period, LT is commonly complicated by a confusional syndrome. The possible role of persisting hepatic encephalopathy in its development has not been clearly established. The origin is usually considered multifactorial and relates to complications following LT, such as infections, rejection, primary liver dysfunction, immunosuppressors, etc.… The diagnosis and treatment is based in the recognition of comorbidities and optimal care of metabolic disturbances. Several studies have demonstrated recovery of cognitive function after LT in patients that have exhibited hepatic encephalopathy. However, some deficits may persist specifically among patients with persistent HE. Other factors present before LT that contribute to a worse neuropsychological outcome after LT are diabetes mellitus and alcohol consumption. Long-term after LT, cognitive function may worsen in relation to vascular risk factors.

Acute-on chronic liver failure

Acute-on-chronic liver failure (ACLF) is an increasingly recognised entity encompassing an acute deterioration of liver function in patients with cirrhosis, which is usually associated with a precipitating event and results in the failure of one or more organs and high short term mortality. Prospective data to define this is lacking but there is a large body of circumstantial evidence suggesting that this condition is a distinct clinical entity. From the pathophysiologic perspective, altered host response to injury and infection play important roles in its development. This review focuses upon the current understanding of this syndrome from the clinical, prognostic and pathophysiologic perspectives and indicates potential biomarkers and therapeutic targets for intervention.

Minimal hepatic encephalopathy: follow-up 10 years after successful liver transplantation

BACKGROUND

The long-term effect of liver transplantation (LT) on cognitive functions and the complete reversibility of minimal hepatic encephalopathy are poorly documented. Much evidence indicates that spatial attention improves starting from the immediate period after LT. However, at least in the first 2 years, some cognitive defects seem to persist to some degree, especially for supramodal nonverbal cognitive functions. The aim of this study is to investigate (i) whether the improvements observed in the perioperative period fluctuate or remain stable 10 years after LT and (ii) whether the functions that have been found defective also improve.

METHODS

We called patients previously included in a prospective study (Mattarozzi et al., Arch Neurol 2004; 61: 242) for a further neuropsychological evaluation. We compared the cognitive evaluation after 7 to 10 years with previous data gathered 6 and 18 months after LT.

RESULTS

The improvements obtained in the first 2 years after transplantation remain stable during the 7 to 10 years thereafter, especially for visuospatial attention, F(12,96) 1.70; P=0.04 and selective attention, F(6,66) 3.51; P=0.005. Furthermore, these findings also seem to suggest an improvement in supramodal cognitive functions, such as spatial planning intelligence, measured by the Elithorn Maze Test, F(3,33) 7.42; P=0.002. Verbal short-term memory, F(3,33) 3.69; P=0.038, and visuospatial short-term memory, F(6,64) 2.97; P=0.013, show a more fluctuating trend over time.

CONCLUSIONS

Despite the risk of surgery, the neurotoxicity of immunosuppression therapy, and the effects of aging and related comorbidities, our data indicate that LT is able to significantly improve patients' cognitive functions in the long term.

Focal cortical damage parallels cognitive impairment in minimal hepatic encephalopathy

Little attention has been paid to cortical integrity in patients with minimal hepatic encephalopathy (MHE), although cognitive functions affected in early stages of liver disease are mainly allocated in different neocortical structures. Here we used cortical surface-based analysis techniques to investigate if patterns of cortical thinning accompany the mildest form of HE. To aim this goal, cortical thickness obtained from high-resolution 3T magnetic resonance imaging (MRI) was measured in patients with no MHE (NMHE), MHE, and healthy controls. Further correlation analyses were performed to examine whether scores in the critical flicker frequency (CFF) test, and blood ammonia levels accounted for the loss of cortical integrity in different stages of liver disease. Finally, we assessed group differences in volume of different subcortical regions and their potential relationships with CFF scores/blood ammonia levels. Results showed a focal thinning of the superior temporal cortex and precuneus in MHE patients when compared with NMHE and controls. Relationships between blood ammonia levels and cortical thickness of the calcarine sulcus accounted for impaired visual judgment in patients with MHE when compared to NMHE. Regression analyses between cortical thickness and CFF predicted differences between controls and the two groups of HE patients, but failed to discriminate between patients with NMHE and MHE. Taking together, these findings provide the first report of cortical thinning in MHE patients, and they yield novel insights into the neurobiological basis of cognitive impairment associated with early stages of liver diseases.

Neuroimaging in acute liver failure

Acute liver failure (ALF) is frequently complicated by the development of brain edema that can lead to intracranial hypertension and severe brain injury. Neuroimaging techniques allow a none-invasive assessment of brain tissue and cerebral hemodynamics by means of transcranial Doppler ultrasonography, magnetic resonance and nuclear imaging with radioligands. These methods have been very helpful to unravel the pathogenesis of this process and have been applied to patients and experimental models. They allow monitoring the outcome of patients with ALF and neurological manifestations. The increase in brain water can be detected by observing changes in brain volume and disturbances in diffusion weighted imaging. Neurometabolic changes are detected by magnetic resonance spectroscopy, which provides a pattern of abnormalities characterized by an increase in glutamine and a decrease in myo-inositol. Disturbances in cerebral blood flow are depicted by SPECT or PET and can be monitored and the bedside by assessing the characteristics of the waveform provided by transcranial Doppler ultrasonography. Neuroimaging methods, which are rapidly evolving, will undoubtedly lead to future diagnostic and therapeutic progress that could be very helpful for patients with ALF.

New assessment of hepatic encephalopathy

Hepatic encephalopathy (HE) is a common complication of cirrhosis that requires careful appraisal of the clinical manifestations, evaluation of the underlying neurological disorders, and assessment of liver function and the portal-systemic circulation. This article reviews recent developments in the assessment of HE and discusses the controversy regarding the use of a categorical or a continuous approach in measuring the severity of this condition. New scales facilitate effective monitoring and assessment of episodic HE. Neuropsychological test batteries and neurophysiological tests are of value for evaluating cognitive function in outpatients and can establish the diagnosis of minimal HE, and the severity of low-grade HE. These tools allow better evaluation of the origin of cognitive complaints and help in estimating the risk of accidents. It is now possible to complete the evaluation with measurement of the effects of cognitive impairment on daily living. In difficult cases, imaging of the brain and portal-systemic circulation with magnetic resonance imaging is especially helpful. Based on these studies, neurological signs and symptoms can be attributed to HE in patients with mild liver disease and in those with complex neurological manifestations. The new methods presented are also valuable for investigating the neurological manifestations occurring after liver transplantation.

Hepatic encephalopathy is associated with posttransplant cognitive function and brain volume

Hepatic encephalopathy (HE) is a common complication of cirrhosis that is associated with brain atrophy and may participate in impaired cognitive function after liver transplantation. This study analyzes the relationship of HE with cognitive function and brain volume after transplantation. A total of 52 consecutive patients with cirrhosis (24 alcohol abuse, 24 prior HE, 14 diabetes mellitus) completed a neuropsychological assessment before liver transplantation and again, 6 to 12 months after transplantation. In 24 patients who underwent the posttransplant assessment, magnetic resonance imaging was performed in addition, with measurement of brain volume and relative concentration of N-acetylaspartate (NAA) and creatine/phosphocreatine (Cr), a neuronal marker, by magnetic resonance spectroscopy. Neuropsychological assessment prior to transplantation identified minimal HE in 28 patients. All cognitive indexes improved after liver transplantation, but 7 patients (13%) showed persistent mild cognitive impairment. Global cognitive function after transplantation was poorer in patients with the following variables before liver transplantation: alcohol etiology, diabetes mellitus, and HE. Brain volume after transplantation was smaller in patients with prior HE. Brain volume correlated to NAA/Cr values (r = 0.498, P = 0.013) and poor motor function (r = 0.41, P = 0.049). In conclusion, the association of HE with cognitive function and brain volume suggests that having experienced HE before liver transplantation impairs the posttransplantation neurological outcome.

Hyponatremic and hepatic encephalopathies: similarities, differences and coexistence

Hyponatremic and hepatic encephalopathy are common causes of metabolic encephalopathy that may coexist in patients with cirrhosis. The clinical picture is common to any metabolic encephalopathy and is characterized by a confusional syndrome that may evolve into coma. Chronic mild or minimal manifestations can be seen in both, but motor symptoms are more common in hepatic encephalopathy. Recent advances show that in addition to clinical manifestations both encephalopathies share some pathogenetic mechanisms. Dysfunction of astrocytes, osmotic changes in the brain and brain edema are present in both situations. Recognition of these abnormalities is important to plan therapy. New drugs that affect brain hydration may be useful for both encephalopathies.