The influence of HE history, HE status and neuropsychological test type on learning ability in patients with cirrhosis

Renormalization of Thalamic Sub-Regional Functional Connectivity Contributes to Improvement of Cognitive Function after Liver Transplantation in Cirrhotic Patients with Overt Hepatic Encephalopathy

Objective

The role of preoperative overt hepatic encephalopathy (OHE) in the neurophysiological mechanism of cognitive improvement after liver transplantation (LT) remains elusive. This study aimed to explore changes in sub-regional thalamic functional connectivity (FC) after LT and their relationship with neuropsychological improvement using resting-state functional MRI (rs-fMRI) data in cirrhotic patients with and without a history of OHE.

Materials and Methods

A total of 51 cirrhotic patients, divided into the OHE group (n = 21) and no-OHE group (n = 30), and 30 healthy controls were enrolled in this prospective study. Each patient underwent rs-fMRI before and 1 month after LT. Using 16 bilateral thalamic subregions as seeds, we conducted a seed-to-voxel FC analysis to compare the thalamic FC alterations before and after LT between the OHE and no-OHE groups, as well as differences in FC between the two groups of cirrhotic patients and the control group. Correction for multiple comparisons was conducted using the false discovery rate (p < 0.05).

Results

We found abnormally increased FC between the thalamic sub-region and prefrontal cortex, as well as an abnormally decreased FC between the bilateral thalamus in both OHE and no-OHE cirrhotic patients before LT, which returned to normal levels after LT. Compared with the no-OHE group, the OHE group exhibited more extensive abnormalities prior to LT, and the increased FC between the right thalamic subregions and right inferior parietal lobe was markedly reduced to normal levels after LT.

Conclusion

The renormalization of FC in the cortico-thalamic loop might be a neuro-substrate for the recovery of cognitive function after LT in cirrhotic patients. In addition, hyperconnectivity between thalamic subregions and the inferior parietal lobe might be an important feature of OHE. Changes in FC in the thalamus might be used as potential biomarkers for recovery of cognitive function after LT in cirrhotic patients.

Clinical, neuropsychological and neurophysiological indices and predictors of hepatic encephalopathy (HE)

BACKGROUND AND AIMS

The occurrence of overt hepatic encephalopathy (HE) marks a significant progression in the natural history of liver disease. The aims of the present study were to: 1) describe a large cohort of patients with cirrhosis in terms of neuropsychological or neurophysiological HE indices, and 2) test if the severity of liver disease and/or any such indices [Psychometric Hepatic Encephalopathy Score (PHES), Scan test, electroencephalography (EEG)] predicted mortality/HE risk in a subgroup of such cohort.

METHOD

Four hundred and sixty-one patients with cirrhosis (59 ± 10 years; 345 males) were included; information on previous overt HE episodes was available in 407. Follow-up information on mortality/HE-related hospitalization in 134/127 respectively. Information on previous overt HE episodes and both mortality and HE-related hospitalization over the follow-up in 124.

RESULTS

Patients with a history of overt HE (60%) had poorer liver function, worse neuropsychiatric indices, higher ammonia levels and higher prevalence of portal-systemic shunt. The risk of HE-related hospitalization over the follow-up was higher in patients with higher MELD score and worse Scan performance. Mortality was higher in those with higher MELD. Among patients without a history of overt HE, those with worse PHES had higher HE risk. Among patients with a history, those with higher MELD, better PHES and worse Scan performance had higher HE risk.

CONCLUSIONS

In patients without previous overt HE episodes, neuropsychological and neurophysiological tests predict HE, while in those with previous overt HE episodes, HE development largely depends on the severity of liver dysfunction.

Cognitive Impairment After Resolution of Hepatic Encephalopathy: A Systematic Review and Meta-Analysis

Hepatic encephalopathy (HE) is one of the most disabling metabolic diseases. It consists of a complication of liver disease through the action of neurotoxins, such as excessive production of ammonia from liver, resulting in impaired brain function. Its prevalence and incidence are not well known, although it has been established that up to 40% of cirrhotic patients may develop HE. Patients with HE episodes display a wide range of neurological disturbances, from subclinical alterations to coma. Recent evidence suggests that the resolution of hepatic encephalopathy does not fully restore cognitive functioning in cirrhotic patients. Therefore, the aim of this review was to evaluate the evidence supporting the presence of lingering cognitive deficits in patients with a history of HE compared to patients without HE history and how liver transplant affects such outcome in these patients. We performed two distinct meta-analysis of continuous outcomes. In both cases the results were pooled using random-effects models. Our results indicate that cirrhotic patients with a history of HE show clear cognitive deficits compared to control cirrhotic patients (Std. Mean Difference (in SDs) = −0.72 [CI 95%: −0.94, −0.50]) and that these differences are not fully restored after liver transplant (Std. Mean Difference (in SDs) = −0.48 [CI 95%: −0.77, −0.19]).