Hepatopulmonary Syndrome and Portopulmonary Hypertension in Children: Recent Advances in Diagnosis and Management

A high rate of post thrombotic complication in pediatric portal vein thrombosis

INTRODUCTION

Portal vein thrombosis (PVT) is a rare disease in children and may be complicated by portal hypertension (PH), hepatopulmonary syndrome (HPS) and portopulmonary hypertension (PPHTN) but their incidence and risk factors are unknown.

METHODS

An observational, retrospective cohort study of all consecutive children (≤18 years) with PVT treated at the Emma Children's Hospital Amsterdam University Medical Centers between January 1996 and January 2022 was conducted to identify the incidence and risk factors of these post thrombotic complications (PTC) in pediatric patients.

RESULTS

In total 43/ 703 thrombosis patients had PVT (boys 72.1 %; mean age 1.3 ± 0.5 years). Overall, 51 % of patients developed PH (n = 22), complicated by PPHTN in one of them. In 16 of 22 patients, PVT presented with portal hypertension. Clinically relevant bleeding due to portal hypertension occurred in 13 (59.1 %) patients with PH. The mean age at the first clinically relevant bleeding was 5.1 ± 5.9 years. Risk factors for the development of PH were lack of complete thrombus resolution (OR 24.3, 95 % CI 1.2-7.0; p = 0.008) and unprovoked VTE (OR, 35.4; 95 % CI 1.4-6.3; p = 0.012). Median time from PVT to PH was 137 days (range: 0 days to 5.04 years).

CONCLUSION

We demonstrated that half of the patients develop PH after PVT, with a lack of thrombus resolution and unprovoked VTE as independent risk factors. This high incidence underlines the importance of long-term standardized follow-up of patients after PVT and standard screening in patients at risk of PTC.

Model for End-Stage Liver Disease/Pediatric End-Stage Liver Disease exception policy and outcomes in pediatric patients with hepatopulmonary syndrome requiring liver transplantation

Hepatopulmonary syndrome (HPS) is associated with increased waitlist mortality in liver transplantation (LT) candidates. Children with HPS are granted Model for End-Stage Liver Disease (MELD)/Pediatric End-Stage Liver Disease (PELD) exception points for waitlist prioritization in the United States based on criterion developed for adults. In this study, the impact of this MELD/PELD exception policy on post-LT survival in children was examined. A retrospective cohort of patients aged younger than 18 years with a MELD/PELD exception request who underwent LT between 2007 and 2018 were identified in the Scientific Registry of Transplant Recipients. Patients were stratified by waitlist partial pressure of arterial oxygen (PaO 2 ) to assess risk factors for waitlist mortality and post-LT survival. Among 3082 pediatric LT recipients included in the study, 124 patients (4%) received MELD/PELD exception points for HPS. Patients with HPS were a median age of 9 years (interquartile range: 6, 12 years), 54.8% were girls, and 54% were White. Most patients (87.9%) were listed with laboratory MELD/PELD scores <15. Waitlist mortality for patients with HPS exception points was rare and not different from patients without HPS. When stratified by pre-LT PaO 2 , hypoxemia severity was not associated with differences in 1-, 3-, or 5-year survival rates after LT ( p = 0.13). However, patients with HPS showed a slightly lower survival rate at 5 years compared with patients without HPS (88.7% vs. 93.4%; p = 0.04). MELD/PELD exceptions for children with HPS mitigated waitlist mortality, and recipients with HPS experienced excellent 5-year survival after LT, although slightly lower than in patients without HPS. Unlike adults with HPS, the severity of pre-LT hypoxemia in children does not impact post-LT survival. These data suggest that adult criteria for granting MELD/PELD exception points may not appropriately capture HPS severity in pediatric patients. Further prospective multicenter studies to examine the risk factors predicting negative survival outcomes in children with HPS are warranted.

Beyond Varices: Complications of Cirrhotic Portal Hypertension in Pediatrics

Complications of cirrhotic portal hypertension (PHTN) in children are broad and include clinical manifestations ranging from variceal hemorrhage, hepatic encephalopathy (HE), ascites, spontaneous bacterial peritonitis (SBP), and hepatorenal syndrome (HRS) to less common conditions such as hepatopulmonary syndrome, portopulmonary hypertension, and cirrhotic cardiomyopathy. The approaches to the diagnosis and management of these complications have become standard of practice in adults with cirrhosis with many guidance statements available. However, there is limited literature on the diagnosis and management of these complications of PHTN in children with much of the current guidance available focused on variceal hemorrhage. The aim of this review is to summarize the current literature in adults who experience these complications of cirrhotic PHTN beyond variceal hemorrhage and present the available literature in children, with a focus on diagnosis, management, and liver transplant decision making in children with cirrhosis who develop ascites, SBP, HRS, HE, and cardiopulmonary complications.

Consensus on the management of complications of cirrhosis of the liver in pediatrics

The Asociación Mexicana de Hepatología A.C. carried out the Consensus on the Management of Complications of Cirrhosis of the Liver in Pediatrics to provide physicians with useful information for treating said complications. A group of pediatric gastroenterologists and experts in nutrition, nephrology, and infectious diseases participated and reviewed the medical literature. The Delphi method was applied to obtain the level of agreement on the statements that were formulated. The statements were sent to the participants to be analyzed and voted upon, after which they were discussed in virtual sessions, and the final versions were produced. The aim of the consensus results was to issue indications for the management of pediatric patients with liver cirrhosis, to prevent or control complications.

Improved survival in children with HPS: Experience from two high volume liver transplant centers across continents

BACKGROUND

Severe HPS increases morbidity and mortality after LT in children. We reviewed the combined experience of LT for HPS in children from two LT centers in Europe and Asia.

METHODS

All children with "proven" HPS as per ERS Task Force criteria (detailed in manuscript) who underwent LT were categorized into M (PaO₂ ≥80 mmHg), Mo (PaO₂  = 60-79 mmHg), S (50-59 mmHg), and VS (PaO₂ <50 mmHg) HPS, based on room air PaO₂ .

RESULTS

Twenty-four children with HPS underwent 25 LT (one re-transplantation) at a median age of 8 years (IQR, 5-12), after a median duration of 8 (4-12) months following HPS diagnosis. Mechanical ventilation was required for a median of 3 (1.5-27) days after LT. Ten children had "S" post-operative hypoxemia, requiring iNO for a median of 5 (6-27) days. "VS" category patients had significantly prolonged invasive ventilation (median 35 vs. 3 and 1.5 days; p = .008), ICU stay (median 39 vs. 8 and 8 days; p = .007), and hospital stay (64 vs. 26.5 and 23 days; p < .001) when compared to "S" and "M/Mo" groups, respectively. The need for pre-transplant home oxygen therapy was the only factor predicting need for re-intubation. Patient and graft survival at 32 (17-98) months were 100% and 95.8%. All children ultimately had complete resolution of HPS.

CONCLUSIONS

VS HPS is associated with longer duration of mechanical ventilation and hospital stay, which emphasizes the need for early LT in these children.

Reliable Detection of Intrapulmonary Shunts Using Contrast-Enhanced Echocardiography in Children With Portal Hypertension or Portosystemic Shunt

OBJECTIVES

The aim of this study was to analyze if contrast-enhanced echocardiography (CEE) is as reliable as lung perfusion scintigraphy (LPS) to detect intrapulmonary shunting (IPS) in children with portal hypertension (PHTN) or congenital/surgical portosystemic shunts (PSS) and to define the number of cardiac cycles required to exclude intrapulmonary shunting.

METHODS

Inclusion criteria for this cross-sectional study were: (1) presence of PHTN or PSS diagnosed on abdominal ultrasound, (2) technically valid saline contrast echocardiography, (3) lung perfusion scintigraphy within 6 months of CEE. The number of cardiac cycles between right atrial opacification and the arrival of contrast in the left atrium were counted. We analyzed our CEE data at three and five cardiac cycles and compared them with LPS results.

RESULTS

The study population was composed of 78 children (38 girls, 49%) ages 2.1-18.8 years (mean 9.8). Sixty-nine patients had PHTN (88%), and nine had a PSS (11%). Eleven subjects (14%) presented evidence of IPS on LPS. Peripheral oxygen saturation was lower in the subjects with IPS detected on LPS (95.3 ± 1.7% vs 99.0 ± 1.4%; P < 0.01). Comparison of LPS with CEE before three and five cardiac cycles showed that CEE is highly specific (95.7%) as early as three cardiac cycles with markedly better sensitivity (72.7%) when using five cardiac cycles. Furthermore, a negative study using five cardiac cycles ruled out IPS with a 95% negative predictive value. The cardiac cycle at which the bubbles appeared in the left atrium was inversely correlated to the shunt index measured using LPS (r = -0.563; P = 0.001).

CONCLUSION

CEE is sufficient for the screening of IPS in children with PHTN or congenital/surgical PSS, obviating the need for LPS.

Advances in management of end stage liver disease in children

End stage liver disease (ESLD) is an irreversible condition that is a management challenge to the paediatrician. The aetiology and natural history of ESLD in children is not only distinct from adults but also variable depending upon the age of presentation. Children are especially vulnerable to developmental delay, frailty and malnutrition. Nutritional support is the cornerstone of management of these children as it has a significant impact on the clinical course and survival, both before and after transplantation. Further, the complications of ESLD in children including but not limited to, ascites, portal hypertension, spontaneous bacterial peritonitis and encephalopathy raise unique management challenges. In this review we provide a concise review of and highlight recent advances in the management of paediatric ESLD.

Non-invasive assessment of intrapulmonary shunt and ventilation to perfusion ratio in children with hepatopulmonary syndrome before and after liver transplantation

OBJECTIVES

To use the oxyhaemoglobin dissociation curve (ODC) to non-invasively measure the ventilation perfusion ratio (V_A/Q) and right-to-left intrapulmonary vascular shunt before and after liver transplantation (LT) in children with hepatopulmonary syndrome (HPS). To investigate whether the right-to-left shunt derived by ODC correlated with the shunt derived by technetium-99 labelled macroaggregated albumin lung perfusion scan (MAA).

METHODS

A retrospective cohort study at King's College Hospital NHS Foundation Trust, London, UK was performed between 1998 and 2016. The V_A/Q and right-to-left shunt were non-invasively measured pre and post LT. The pre-LT right-to-left intrapulmonary shunt was also measured by MAA. The non-invasively derived pre-LT shunt was correlated with the shunt derived by MAA.

RESULTS

Fifteen children with HPS were studied with a median (IQR) age at LT of 8.8 (6.6-12.9) years. The median (IQR) pre-LT V_A/Q [0.49 (0.42-0.65)] was lower compared to the post-LT V_A/Q [0.61 (IQR 0.54-0.72), p = 0.012]. The median (IQR) pre-LT shunt was 19 (3-24) % which decreased to zero in all but one children post-LT, (p = 0.001). The MAA-derived shunt was significantly positively correlated with the ODC-derived shunt (r = 0.783, p = 0.001). The mean (SD) difference between shunt derived by ODC and shunt derived by MAA was 0.5 (7.2) %.

CONCLUSIONS

Ventilation/perfusion impairment reverses but not completely resolves after liver transplantation in children with hepatopulmonary syndrome. The non-invasive method for estimating intrapulmonary shunting could be used as an alternative to the macroaggregated albumin scan in this population.

Clinical outcomes and risk factors of hepatopulmonary syndrome in children

Hepatopulmonary syndrome (HPS) is defined as three distinct features: liver disease, hypoxemia, and intrapulmonary vasodilation. The purpose of this study was to investigate the clinical outcomes of pediatric HPS and to identify the risk factors for HPS in children with biliary atresia (BA). We performed a retrospective cohort study of all children who were diagnosed with HPS between 2000 and 2018 at Seoul National University Hospital. The clinical features and outcomes of the 10 patients diagnosed with HPS were reviewed. To clarify the risk factors of HPS in patients with BA, we reviewed 120 patients diagnosed with BA. Underlying liver disease was BA in 8 patients, portal vein agenesis in 1 patient, and portal vein thrombosis in 1 patient. A total of 7 patients underwent liver transplantation (LT). Currently, all seven patients, including 3 patients with severe HPS, survived after LT. The prevalence of HPS in children with BA was 7%. Polysplenia/interrupted inferior vena was the only risk factor for HPS in BA patients in multivariate analysis. The Pediatric End-Stage Liver Disease score was not associated with the development of HPS. Children with severe HPS undergoing LT had excellent outcomes. Screening for HPS in children with BA is required regardless of the severity of liver diseases.

Pulmonary Manifestations of Gastrointestinal, Pancreatic, and Liver Diseases in Children

Pulmonary manifestations of gastrointestinal (GI) diseases are often subtle, and underlying disease may precede overt symptoms. A high index of suspicion and a low threshold for consultation with a pediatric pulmonologist is warranted in common GI conditions. This article outlines the pulmonary manifestations of different GI, pancreatic, and liver diseases in children, including gastroesophageal reflux disease, inflammatory bowel disease, pancreatitis, alpha1-antitrypsin deficiency, nonalcoholic fatty liver disease, and complications of chronic liver disease (hepatopulmonary syndrome and portopulmonary hypertension).

Pharmacological management of portal hypertension and its complications in children: lessons from adults and opportunities for the future

INTRODUCTION

Portal hypertension (PHT) and its complications in children are thought to be distinct from adult PHT in several areas, including the underlying bio-physiology of a child in which PHT develops, but also because of the pediatric-specific etiologies that drive disease progression. And yet pharmacologic approaches to PHT in children are mainly based on adult data, modified for pediatric practice. This reality has been driven by a lack of data specific to children.

AREAS COVERED

The authors discuss current therapeutic approaches to PHT in children, including management of acute gastrointestinal variceal bleed, pharmacotherapy in prophylaxis, and established and emerging therapies to combat systemic co-morbidities that result from PHT. The few areas where pediatric-specific data exist are highlighted and the many gaps in knowledge that remain unresolved are underscored.

EXPERT OPINION

Despite decades of experience, optimal management of pediatric PHT remains undefined. In large part, this can be directly linked to a lack of basic understanding related to the unique pathophysiology and natural history that defines PHT in children. As a result, meaningful research into the utility and effectiveness of pharmacotherapy in children with PHT remains in its infancy. Large, multi-center, prospective studies will be needed to begin to establish an infrastructure on which a pediatric-specific research agenda can be built.

Long-term Outcomes and Health Perceptions in Pediatric-onset Portal Hypertension Complicated by Varices

OBJECTIVES

Outcomes of pediatric-onset portal hypertension are poorly defined. We aimed to assess population-based long-term outcomes of pediatric-onset portal hypertension complicated by varices.

METHODS

All children with esophageal varices (n = 126) were identified from 14,144 single nationwide referral center endoscopy reports during 1987 to 2013, and followed up through national health care and death registers. A questionnaire was sent to survivors (n = 94) of whom 65 (69%) responded.

RESULTS

Nineteen underlying disorders included biliary atresia (35%), extrahepatic portal vein obstruction (35%), autosomal recessive polycystic kidney disease (7%), and other disorders (23%). During median follow-up of 15.2 (range 0.5-43.1) years patients underwent median 9 (1-74) upper gastrointestinal endoscopies. Esophageal varices were first observed at a median age of 4.0 (0.3-18.2) years, 112 (89%) patients underwent median 6 (1-56) sclerotherapy/banding sessions, and 61 (48%) experienced median 2 (range 1-20) variceal bleeding episodes. Forty-eight surgical shunt procedures were performed to 41 (36%) patients and 38% underwent liver transplantation. Portal hypertensive biliopathy was diagnosed in 4 patients. Hepatopulmonary syndrome necessitated liver transplantation in 2 patients, hepatic encephalopathy in 2, and hepatorenal syndrome in 1. No patient died of variceal bleeding. Patient-reported perception of health on a scale of 1 to 10 was 9 (range 4-10), and 86% reported no current symptoms attributable to esophageal varices.

CONCLUSIONS

Pediatric-onset portal hypertension is a heterogeneous disease with significant long-term morbidity, requiring multimodal approach with considerable resources and continuation of follow-up in adulthood. Although mortality to variceal bleeding was avoided, bleeding episodes recurred also in adulthood, while patient-reported health of long-term survivors was encouraging.