Prophylaxis of hepatic encephalopathy: current and future drug targets

Hepatic encephalopathy is described by a broad spectrum of neurological and psychiatric aberrations resulting due to advanced liver dysfunction. It is a neurological disorder due to hepatic insufficiency and/or portosystemic shunts. Its clinical presentation includes neuropsychiatric dysfunction ranging from subclinical changes to comatose state. It is a sign of poor prognosis in cirrhotics with a high 1-year mortality. Each episode of hepatic encephalopathy leads to high hospitalization rate, poor prognosis and raised burden of healthcare. Primary prophylaxis is prevention of initial occurrence and secondary prophylaxis is prevention of reappearance of hepatic encephalopathy in subjects who had prior history. Early detection and management of triggers is very important in the treatment of hepatic encephalopathy. The initial choice of treatment is still lactulose, as it is effective in minimal, overt, and recurrent hepatic encephalopathy. Rifaximin is equally effective as lactulose in managing hepatic encephalopathy and is better tolerated. Branch chain amino acids are beneficial in subjects who are protein intolerant. L-ornithine L-aspartate and probiotics are also useful in the management of hepatic encephalopathy. Rifaximin along with lactulose is effective in managing overt and recurrent hepatic encephalopathy. Large portosystemic shunts embolization and liver transplant is efficacious in certain group of patients. Nutritional therapy and fecal microbiota transplantation are newer therapies for hepatic encephalopathy but the evidences are limited, more research is required to prove their efficacy. Involvement of hospital pharmacists, telemedicine, and providing education are also beneficial in managing hepatic encephalopathy.

Surgical management of extrahepatic portal vein obstruction in children: advantages of MesoRex shunt compared with distal splenorenal shunt

PURPOSE

To review surgical management of extrahepatic portal vein obstruction (EHPVO) at Red Cross War Memorial Children's Hospital and compare MesoRex shunt (MRS) with distal splenorenal shunt (DSRS).

METHODS

This is a single-centre retrospective review documenting pre- and post-operative data in 21 children. Twenty-two shunts were performed, 15 MRS and 7 DSRS, over an 18-year period. Patients were followed up for a mean of 11 years (range 2-18). Data analysis included demographics, albumin, prothrombin time (PT), partial thromboplastin time (PTT), International normalised ratio (INR), fibrinogen, total bilirubin, liver enzymes and platelets before the operation and 2 years after shunt surgery.

RESULTS

One MRS thrombosed immediately post-surgery and the child was salvaged with DSRS. Variceal bleeding was controlled in both groups. Significant improvements were seen amongst MRS cohort in serum albumin, PT, PTT, and platelets and there was a mild improvement in serum fibrinogen. The DSRS cohort showed only a significant improvement in the platelet count. Neonatal umbilic vein catheterization (UVC) was a major risk for Rex vein obliteration.

CONCLUSION

In EHPVO, MRS is superior to DSRS and improves liver synthetic function. DSRS does control variceal bleeding but should only be considered when MRS is not technically feasible or as a salvage procedure when MRS fails.

Prevention of post-tips hepatic encephalopathy: The search of the ideal candidate

Transjugular intrahepatic portosystemic shunt (TIPS) has been used since more than 25 years to treat some of the complications of portal hypertension, especially variceal bleeding and ascites refractory to conventional therapy. TIPS establishes a communication between the portal and hepatic veins, inducing the blood to shift from the splanchnic circulation into the systemic vascular bed with the aim of decompressing the portal venous system, and avoids the major complications of portal hypertension. However, the shunt of the portal blood into the systemic circulation is the cause of one of the major complications of the procedure: the post-TIPS hepatic encephalopathy (HE). To date, few pharmacological treatment has been proven effective to prevent this complication and thus, the identification of patients at high risk of post-TIPS hepatic encephalopathy and the patients' carefully selection is the only way to prevent this frequent complication.

Meso-Rex bypass versus portosystemic shunt for the management of extrahepatic portal vein obstruction in children: systematic review and meta-analysis

PURPOSE

Extrahepatic portal vein obstruction (EHPVO) is a major cause of non-cirrhotic portal hypertension in children. Surgical procedures for EHPVO include portosystemic shunts (PSS) and meso-Rex bypass (MRB). We conducted a systematic review and meta-analysis to compare the effectiveness of MRB versus PSS in EHPVO patients.

METHODS

A systematic literature search was performed using four databases. Articles reporting EHPVO and comparing patients who received MRB and PSS were included in the analysis.

RESULTS

We retrieved 851 papers, of which five observational studies met the inclusion criteria. There was no difference in shunt complications, mortality, or gastrointestinal bleeding after surgery between MRB and PSS in the meta-analysis. MRB had increased shunt complications compared with PSS in the non-comparative studies. MRB had a potential advantage over PSS in long-term prognosis in one comparative study. Overall, the quality of the evidence was low.

CONCLUSIONS

Based on available data, our meta-analysis indicates that MRB does not increase shunt complications, mortality, or gastrointestinal bleeding after surgery. The present study did not reveal superiority for either MRB or PSS. The paucity of well conducted trials in this area justifies future multicenter studies and studies that examine long-term outcomes.

Characterization and natural history of congenital intrahepatic portosystemic shunts

Congenital intrahepatic portosystemic shunts are rare vascular malformations in which abnormal communications are created between the portal veins and the hepatic veins or the inferior vena cava system. Diagnosis is made by prenatal or postpartum ultrasound. Published data regarding presentation, symptoms, and prognosis is scarce. This study aimed to better understand the natural history and the course of the intrahepatic portosystemic shunts. Data were collected from children in two medical centers who were diagnosed with congenital intrahepatic portosystemic shunts on either prenatal or postnatal sonographic screening. The subjects' medical information was collected including demographics, medical background, and sonographic and clinical outcome. Blood test results including ammonia levels and liver function tests were documented, as well as the sonographic dimensions of the shunt vessels and the spleen size. The data were analyzed using various statistical methods. Twenty-three children with portosystemic shunts were found and reviewed. Eight children were excluded from the study since records and follow-up were insufficient. Fifteen patients were included in the study (six females). All had intrahepatic shunt diagnosed either by prenatal screening or postnatal abdominal ultrasound and had more than one ultrasound and repeated blood tests. Shunt closure was observed in all children within a mean of 114.31 ± 115.05 days (median 84). There was no correlation between liver enzymes, ammonia, and ultrasound vascular and splenic diameters to time to closure. None of the children had any hepatic or other sequelae.Conclusions: Our study suggests that congenital intrahepatic portosystemic shunt is a benign, self-limiting condition in which no correlation between the size of the shunt and the blood ammonia level to the outcome of the shunt was found. This is the first study that correlated radiological measures to the outcome. These results suggest that the treating physician should reassure families and conduct minimal follow-up and interventions in children with such conditions. Further, larger and prospective studies should be done to corroborate these conclusions. What is Known: • Characteristics and natural history of intrahepatic portosystemic shunts are less defined. • The natural course of the intrahepatic malformations varies, but spontaneous, self-resolution of small shunts, usually occures within 1 to 2 years. What is New: • In this study, congenital intrahepatic portosystemic shunt was shown to be benign, self-limiting condition in which all shunts closed within 3 months. • No correlation between the size of the shunt and the blood ammonia level to the outcome of the shunt was found.

Predicting the available space for liver transplantation in cirrhotic patients: a computed tomography-based volumetric study

BACKGROUND

Anthropometric parameters (weight, height) are usually used for quick matching between two individuals (donor and recipient) in liver transplantation (LT). This study aimed to evaluate clinical factors influencing the overall available space for implanting a liver graft in cirrhotic patients.

METHODS

In a cohort of 275 cirrhotic patients undergoing LT, we calculated the liver volume (LV), cavity volume (CV), which is considered the additional space between the liver and the right hypocondrium, and the overall volume (OV = LV + CV) using a computed tomography (CT)-based volumetric system. We then chose the formula based on anthropometric parameters that showed the best predictive value for LV. This formula was used to predict the OV in the same population. Factors influencing OV variations were identified by multivariable logistic analysis.

RESULTS

The Hashimoto formula (961.3 × BSA_D-404.8) yielded the lowest median absolute percentage error (21.7%) in predicting the LV. The median LV was 1531 ml. One-hundred eighty-five patients (67.2%) had a median CV of 1156 ml (range: 70-7006), and the median OV was 2240 ml (range: 592-8537). Forty-nine patients (17%) had an OV lower than that predicted by the Hashimoto formula. Independent factors influencing the OV included the number of portosystemic shunts, right anteroposterior abdominal diameter, model for end-stage liver disease (MELD) score > 25, high albumin value, and BMI > 30.

CONCLUSIONS

Additional anthropometric characteristics (right anteroposterior diameter, body mass index) clinical (number of portosystemic shunts), and biological (MELD, albumin) factors might influence the overall volume available for liver graft implantation. Knowledge of these factors might be helpful during the donor-recipient matching.

Outcome of paediatric portopulmonary hypertension in the modern management era: A case report of 6 patients

Portopulmonary hypertension is a rare but serious complication of portal hypertension or portosystemic shunting. Portopulmonary hypertension is an indication for liver transplantation or shunt closure. However, liver transplantation is contraindicated in patients with severe pulmonary arterial hypertension. Reported mortality rates are high in children with portopulmonary hypertension and there are scarce recommendations on its management. Our aim was to report on our real-world experience of managing portopulmonary hypertension in a specialised centre. We describe a series of 6 children with portopulmonary hypertension. Their median age at diagnosis was 13 years (range 10-15). The underlying liver conditions were cirrhosis of unknown origin (1), congenital portocaval shunts (3), biliary atresia (1), and portal vein cavernoma with surgical mesenterico-caval shunt (1). Median mean pulmonary arterial pressure was 47 mmHg (range 32-70), and median pulmonary vascular resistance was 6.6 Wood units (range 4.3-15.4). All patients except one were treated with a combination of pulmonary arterial hypertension-specific therapy (phosphodiesterase type 5 inhibitors and/or endothelin receptor antagonists and/or prostacyclin analogues). Three patients then benefited from shunt closure and the others underwent liver transplantation. Five patients showed improvement or stabilisation of pulmonary arterial hypertension with no deaths after a mean follow-up of 39 months. Based on our limited experience, early and aggressive treatment with a combination of pulmonary arterial hypertension-specific therapy significantly improves patients' haemodynamic profile and enables the performance of liver transplantation and shunt closure with satisfactory outcomes.

Endovascular treatment of surgical mesoportal and portosystemic shunt dysfunction in pediatric patients

BACKGROUND

Published data describing the endovascular treatment of dysfunctional mesoportal and portosystemic shunts in the pediatric population are limited.

OBJECTIVE

We sought to describe the treatment and follow-up of such shunts managed by interventional radiology at a single pediatric hospital. We hypothesized that stenotic and occluded pediatric portosystemic and mesoportal shunts can be maintained patent by interventional radiology in the moderate term.

MATERIALS AND METHODS

We conducted a single-center retrospective study at a tertiary pediatric hospital. We included children with surgical mesoportal (meso-Rex) or portosystemic (mesocaval, splenorenal or splenocaval) shunts treated with attempted angioplasty or stenting from 2010 to 2018. Technical success was defined as catheterization and intervention upon the shunt with venographic evidence of flow improvement. The primary outcome variables were shunt patency at 1 month, 6 months, 12 months and 24 months post-procedure and freedom from reintervention.

RESULTS

Twenty pediatric patients (11 boys, 9 girls; mean age 8.25 years, range 1.3-17 years) met inclusion criteria. Fifty-two interventions (primary and reintervention) on 13 splenorenal, 3 meso-Rex, 2 mesocaval and 2 splenocaval shunts were performed because of evidence of shunt failure, including gastrointestinal bleeding, hypersplenism, or radiographic evidence of a flow defect. The 11 stenotic shunts were treated with 100% technical success, while the remaining 9 occluded shunts were treated with 66.7% technical success. The mean number of reinterventions was 1.9 (standard deviation [SD] = 3.1) per child, which did not differ between stenotic and occluded shunts (P=0.24). Primary patency at 1-month, 6-month, 12-month and 24-months follow-up visits was 17/17 (100%), 10/16 (62.5%), 7/15 (46.7%) and 4/10 (40%), respectively. However, 100% of shunts were either primary patent or primary-assisted patent by endovascular reintervention. There were no cases of shunt occlusion following initial technical success. Finally, the median freedom from reintervention duration was 387 days (SD=821 days).

CONCLUSION

Dysfunctional portosystemic surgical shunts are effectively managed by endovascular methods. While many shunts require reintervention, combined primary patency and assisted primary patency rates are excellent.

Agenesis of hepatic lobes in a dog

Agenesis of a hepatic lobe is an extremely rare congenital anomaly and only one dog have been reported in veterinary literature. We encountered a dog with this anomaly diagnosed by Computed tomography (CT) and portography. A two-year-old, 6.9-kg female Shih tzu dog was presented with vomiting and anorexia. The dog had no history of abdominal surgery or trauma. Biochemical analysis showed elevated plasmatic liver enzymes. CT revealed the absence of the liver parenchyma and vascular system of the left lobe, quadrate lobe and papillary process of the caudate lobe. A portosystemic shunt was also observed. The liver parenchyma and vascular system of these lobes were not detected under digital subtraction angiography during laparotomy. Furthermore, the liver parenchyma and vascular system of these lobes were not detected even when the remaining liver volume increased two months after treating the shunt vessel. CT proved itself a good option for antemortally diagnosis of hepatic agenesis in a dog.

Portal hypertension: The desperate search for the placenta

We propose that the circulatory impairments produced, in both portal hypertension and liver cirrhosis, to a certain degree resemble those characterizing prenatal life in the fetus. In fact, the left-right circulatory syndrome is common in cirrhotic patients and in the fetus. Thus, in patients with portal hypertension and chronic liver failure, the re-expression of a blood circulation comparable to fetal circulation is associated with the development of similar amniotic functions, i.e., ascites production and placenta functions, and portal vascular enteropathy. Therefore, these re-expressed embryonic functions are extra-embryonic and responsible for prenatal trophism and development.

Acquired hepatocerebral degeneration (AHD): a peculiar neurological impairment in advanced chronic liver disease

We discuss the case of a rare and often unrecognized neurologic syndrome, called Acquired Hepatocerebral Degeneration (AHD), observed in patients with advanced liver disease and portosystemic shunts. The clinical manifestations can be very heterogeneous and in our case included a combination of cerebellar and extrapyramidal signs, arisen in a period of few days. Brain Magnetic Resonance Imaging (MRI) showed, in T1-weighted images, diffuse bilateral hyper intensities in basal ganglia and biemispheric brain and cerebellar cortices, resembling paramagnetic deposits. No other neurological impairments, like stroke, infection or neoplasia, were found. It was excluded an episode of acute hepatic encephalopathy. We also ruled out Wilsonian degeneration, iron overload and autoimmune encephalitis and we lastly found high manganese levels as the possible cause of the brain paramagnetic deposits. Even though either serum Mn determination or its accumulation in the brain are not specific for AHD, however the chronic and progressively worsening of the neurological manifestations advocated a degenerative condition, possibly AHD. We finally opted for the early restoration of liver function by OLT, and we observed complete clinical symptoms' resolution and partial MRI reversal after a follow up of 6 months.

Staging of portal hypertension and portosystemic shunts using dynamic nuclear medicine investigations

AIM: To explore portal hypertension and portosystemic shunts and to stage chronic liver disease (CLD) based on the pathophysiology of portal hemodynamics.

METHODS: Per-rectal portal scintigraphy (PRPS) was performed on 312 patients with CLD and liver angioscintigraphy (LAS) on 231 of them. The control group included 25 healthy subjects. We developed a new model of PRPS interpretation by introducing two new parameters, the liver transit time (LTT) and the circulation time between right heart and liver (RHLT). LTT for each lobe was used to evaluate the early portal hypertension. RHLT is useful in cirrhosis to detect liver areas missing portal inflow. We calculated the classical per-rectal portal shunt index (PRSI) at PRPS and the hepatic perfusion index (HPI) at LAS.

RESULTS: The normal LTT value was 24 ± 1 s. Abnormal LTT had PPV = 100% for CLD. Twenty-seven non-cirrhotic patients had LTT increased up to 35 s (median 27 s). RHLT (42 ± 1 s) was not related to liver disease. Cirrhosis could be excluded in all patients with PRSI < 5% (P < 0.01). PRSI > 30% had PPV = 100% for cirrhosis. Based on PRPS and LAS we propose the classification of CLD in 5 hemodynamic stages. Stage 0 is normal (LTT = 24 s, PRSI < 5%). In stage 1, LTT is increased, while PRSI remains normal. In stage 2, LTT is decreased between 16 s and 23 s, whereas PRSI is increased between 5% and 10%. In stage 3, PRSI is increased to 10%-30%, and LTT becomes undetectable by PRPS due to the portosystemic shunts. Stage 4 includes the patients with PRSI > 30%. RHLT and HPI were used to subtype stage 4. In our study stage 0 had NPV = 100% for CLD, stage 1 had PPV = 100% for non-cirrhotic CLD, stages 2 and 3 represented the transition from chronic hepatitis to cirrhosis, stage 4 had PPV = 100% for cirrhosis.

CONCLUSION: LTT allows the detection of early portal hypertension and of opening of transhepatic shunts. PRSI is useful in CLD with extrahepatic portosystemic shunts. Our hemodynamic model stages the evolution of portal hypertension and portosystemic shunts. It may be of use in the selection of patients for interferon therapy.

Transhepatic catheter-directed thrombolysis for portal vein thrombosis after partial splenic embolization in combination with balloon-occluded retrograde transvenous obliteration of splenorenal shunt

A 66-year-old woman underwent partial splenic embolization (PSE) for hypersplenism with idiopathic portal hypertension (IPH). One week later, contrast-enhanced CT revealed extensive portal vein thrombosis (PVT) and dilated portosystemic shunts. The PVT was not dissolved by the intravenous administration of urokinase. The right portal vein was canulated via the percutaneous transhepatic route under ultrasonic guidance and a 4 Fr. straight catheter was advanced into the portal vein through the thrombus. Transhepatic catheter-directed thrombolysis was performed to dissolve the PVT and a splenorenal shunt was concurrently occluded to increase portal blood flow, using balloon-occluded retrograde transvenous obliteration (BRTO) technique. Subsequent contrast-enhanced CT showed good patency of the portal vein and thrombosed splenorenal shunt. Transhepatic catheter-directed thrombolysis combined with BRTO is feasible and effective for PVT with portosystemic shunts.