Editorial: increased cardiac output in cirrhosis - non-invasive assessment of regional blood flow by magnetic resonance angiography

The Glymphatic System May Play a Vital Role in the Pathogenesis of Hepatic Encephalopathy: A Narrative Review

Hepatic encephalopathy (HE) is a neurological complication of liver disease resulting in cognitive, psychiatric, and motor symptoms. Although hyperammonemia is a key factor in the pathogenesis of HE, several other factors have recently been discovered. Among these, the impairment of a highly organized perivascular network known as the glymphatic pathway seems to be involved in the progression of some neurological complications due to the accumulation of misfolded proteins and waste substances in the brain interstitial fluids (ISF). The glymphatic system plays an important role in the clearance of brain metabolic derivatives and prevents aggregation of neurotoxic agents in the brain ISF. Impairment of it will result in aggravated accumulation of neurotoxic agents in the brain ISF. This could also be the case in patients with liver failure complicated by HE. Indeed, accumulation of some metabolic by-products and agents such as ammonia, glutamine, glutamate, and aromatic amino acids has been reported in the human brain ISF using microdialysis technique is attributed to worsening of HE and correlates with brain edema. Furthermore, it has been reported that the glymphatic system is impaired in the olfactory bulb, prefrontal cortex, and hippocampus in an experimental model of HE. In this review, we discuss different factors that may affect the function of the glymphatic pathways and how these changes may be involved in HE.

Diastolic dysfunction on echocardiography does not predict survival after transjugular intrahepatic portosystemic stent-shunt in patients with cirrhosis

BACKGROUND

Cardiac dysfunction is frequently observed in patients with cirrhosis. There remains a paucity of data from routine clinical practice regarding the role of echocardiography in the pre-assessment of transjugular intrahepatic portosystemic stent-shunt.

AIM

Our study aimed to investigate if echocardiography parameters predict outcomes after transjugular intrahepatic portosystemic stent-shunt insertion in cirrhosis.

METHODS

Patients who underwent echocardiography and transjugular intrahepatic portosystemic stent-shunt insertion at the liver unit (Birmingham, UK) between 1999 and 2016 were included. All echocardiography measures (including left ventricle ejection fraction; early maximal ventricular filling/late filling velocity ratio, diastolic dysfunction as per British Society of Echocardiography guidelines) were independently reviewed by a cardiologist. Predictors of 30-day and overall transplant free-survival were assessed.

RESULTS

One Hundred and Seventeen patients with cirrhosis (median age 56 years; 54% alcohol; Child-Pugh B/C 71/14.5%; Model For End-Stage Liver Disease 12) underwent transjugular intrahepatic portosystemic stent-shunt for ascites (n = 78) and variceal haemorrhage (n = 39). Thirty-day and overall transplant-free survival was 90% (n = 105) and 31% (n = 36), respectively, over a median 663 (IQR 385-2368) days follow-up. Model for End-Stage Liver Disease (P < 0.001) and Child-Pugh Score (P = 0.002) significantly predicted 30-day and overall transplant-free survival. Model for End-Stage Liver Disease ≥15 implied three-fold risk of death. Six per cent (n = 7) of patients pre-transjugular intrahepatic portosystemic stent-shunt had a history of ischaemic heart disease and 34% (n = 40) had 1 or more cardiovascular disease risk factors. Fifty per cent (n = 59) had an abnormal echocardiogram and 33% (n = 39) had grade 1-3 diastolic dysfunction. On univariate analysis none of the echocardiography measures pre-intervention were related to 30-day or overall transplant-free survival post-transjugular intrahepatic portosystemic stent-shunt.

CONCLUSIONS

Ventricular, in particular diastolic dysfunction in patients with cirrhosis does not predict survival after transjugular intrahepatic portosystemic stent-shunt insertion. Model for End-Stage Liver Disease and Child-Pugh scores remain the best predictors of survival. Further prospective study is required to clarify the role of routine echocardiography prior to transjugular intrahepatic portosystemic stent-shunt insertion.