Hepatopulmonary syndrome in children with cirrhotic and non-cirrhotic portal hypertension: a single-center experience

Respiratory problems associated with liver disease in children

Respiratory manifestations of chronic liver disease have a profound impact on patient clinical outcomes. Certain conditions within paediatric liver disease have an associated respiratory pathology. This overlap between liver and respiratory manifestations can result in complex challenges when managing patients and requires clinicians to be able to recognise when referral to specialists is required. While liver transplantation is at the centre of treatment, it opens up further potential for respiratory complications. It is established that these complications place patients at risk of longer stays in hospital and reduced survival. Additionally, late post-transplant complications can occur, including post-transplant lymphoproliferative disease and immunosuppression-induced interstitial lung disease. Although rare, it is important for clinicians to recognise these conditions to allow for prompt management. Finally, as liver disease progresses in children, respiratory complications can occur. Hepatopulmonary syndrome can occur in the context of portal hypertension, resulting in increased mortality and poorer quality of life for patients. Another consequence is portopulmonary hypertension, which can be associated with poor survival. Failure to recognise these complications in children may result in poorer outcomes and therefore it is vital that clinicians can establish when referral to a paediatric respiratory medicine specialist is required.

Systemic Complications Secondary to Chronic Liver Disease

The systemic sequelae of chronic liver disease (CLD) may be due to portal hypertension and shunting, malnutrition, and/or a low grade inflammatory state. This article will focus on the consequences of chronic liver disease affecting extrahepatic organs. Portal hypertension underlies many systemic complications of CLD. Aside from varices and ascites, portal hypertension may cause both hepatopulmonary syndrome and portopulmonary hypertension leading to respiratory compromise. Cardiomyopathy may also occur secondary to end stage liver disease. Hepatorenal syndrome is also well recognised and hepatic encephalopathy is a consequence of the effect of liver dysfunction on the brain. Compromise of the immune system is well described in end-stage liver disease leading to sepsis and its consequences. Bony disease including osteoporosis and hepatic arthropathy may both be seen in children with CLD. CLD may be asymptomatic initially but then complications may present as the disease progresses. Furthermore, systemic effects of end stage liver disease may complicate liver transplant. These complications often present insidiously or at the time of acute decompensation. Thus, it is important that healthcare providers are vigilant when caring for children with CLD. This article outlines the secondary complications of CLD with an overview of the definition and diagnosis, pathophysiology, management and prognosis of each.

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.

Pediatric non-cirrhotic portal hypertension: Endoscopic outcome and perspectives from developing nations

Non-cirrhotic portal hypertension (NCPH) forms an important subset of portal hypertension in children. Variceal bleed and splenomegaly are their predominant presentation. Laboratory features show cytopenias (hypersplenism) and preserved hepatic synthetic functions. Repeated sessions of endoscopic variceal ligation or endoscopic sclerotherapy eradicate esophageal varices in almost all cases. After variceal eradication, there is an increased risk of other complications like secondary gastric varices, cholangiopathy, colopathy, growth failure, especially in extra-hepatic portal vein obstruction (EHPVO). Massive splenomegaly-related pain and early satiety cause poor quality of life (QoL). Meso-Rex bypass is the definitive therapy when the procedure is anatomically feasible in EHPVO. Other portosystemic shunt surgeries with splenectomy are indicated when patients present late and spleen-related issues predominate. Shunt surgeries prevent rebleed, improve growth and QoL. Non-cirrhotic portal fibrosis (NCPF) is a less common cause of portal hypertension in children in developing nations. Presentation in the second decade, massive splenomegaly and patent portal vein are discriminating features of NCPF. Shunt surgery is required in severe cases when endotherapy is insufficient for the varices. Congenital hepatic fibrosis (CHF) presents with firm palpable liver and splenomegaly. Ductal plate malformation forms the histological hallmark of CHF. CHF is commonly associated with Caroli’s disease, renal cysts, and syndromes associated with neurological defects. Isolated CHF has a favourable prognosis requiring endotherapy. Liver transplantation is required when there is decompensation or recurrent cholangitis, especially in Caroli’s syndrome. Combined liver-kidney transplantation is indicated when both liver and renal issues are present.

Hepatopulmonary Syndrome: A Nationwide Analysis of Epidemiological Trends and Outcomes From 2012 to 2018

Background

This study was designed to determine the epidemiological trends and adverse outcomes of hepatopulmonary syndrome (HPS).

Methods

This retrospective interrupted trend study analyzed data from the Nationwide Inpatient Sample (NIS) for the years 2012, 2014, 2016 and 2018 to identify adult (≥ 18 years) hospitalizations with a diagnosis of HPS. We highlighted epidemiological trends for HPS. Inpatient mortality, mean length of stay (LOS) and mean total hospital charge (THC) were estimated using multivariate regression trend analysis.

Results

We observed an increase in the total number of HPS hospitalizations from 1,565 in 2012 to 2,495 in 2018, with mean age ranging from 55.8 to 58.1 years. There was a trend towards increasing hospitalizations (P-trend < 0.001) with increasing mean age (P-trend = 0.003) for HPS. Whites made up most of the study population. The inpatient mortality for HPS ranged from 12.4% to 12.6%, but there was no statistically significant trend for mortality (P-trend = 0.534) between 2012 and 2018. Additionally, there was no change in both mean LOS (P-trend = 0.545) and mean THC (P-trend = 0.534) for HPS for these years.

Conclusions

Hospitalizations and mean age for HPS were on the rise. Inpatient mortality ranged from 12.4% to 12.6%; however, a statistically significant trend for mortality was absent.

Impact of hypoxemia on pediatric liver transplantation for hepatopulmonary syndrome

BACKGROUND

The treatment of choice for patients with cirrhosis and HPS is LT. The clinical manifestations associated with hypoxemia result in limitations and a poor health-related quality of life of affected patients. The present report aims to study the differences in outcomes between patients with PaO₂  < 50 mm Hg and those with PaO₂  ≥ 50 mm Hg.

METHODS

This was a retrospective study of 21 patients under 18 years of age conducted from 2001 to 2018; the patients were divided into 2 groups: G1-PaO₂  ≥ 50 mm Hg, 11 patients, and G2-PaO₂  < 50 mm Hg, 10 patients. Demographic, clinical, laboratory, and perioperative data; outcome variables; and post-transplant survival were compared between the groups.

RESULTS

In total, 2/11 (18.2%) patients in G1 and 8/10 (80%) patients in G2 required supplemental oxygen therapy at home (P = .005). Patients in G2 required prolonged MV (median 8.5 days in G2 vs 1 day in G1, P = .015) and prolonged ICU and hospital stays (P = .002 and P = .001, respectively). Oxygen weaning time was longer in G2 (median 127.5 days) than in G1 (median 3 days; P = .004). One (9.1%) patient in G1 and three (30%) patients in G2 died (P = .22). The survival at 90 months was 90.9% in G1 and 70% in G2 (P = .22).

CONCLUSION

The survival between groups was similar. Patients with very severe HPS required a longer MV time, longer ICU and hospital stays, and a longer O₂ weaning time than those with mild, moderate, or severe HPS.

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.

Comparison of Two Diagnostic Criteria for Hepatopulmonary Syndrome-High Prevalence in Biliary Atresia

OBJECTIVES

There is lack of clarity regarding the exact prevalence of hepatopulmonary syndrome (HPS) in pediatric liver diseases owing to lack of standardized diagnostic criteria. Thus, we aimed to do a comparative study of HPS with respect to its prevalence using the available diagnostic criteria.

METHODS

All consecutive children with biliary atresia (BA) and other chronic liver diseases (CLDs) were studied. Prevalence of HPS was compared using the 2 available criteria: demonstration of intrapulmonary vascular dilatation along with either alveolar-arterial oxygen difference (P [A-a] O2) on arterial blood gas analysis of more than 15 mmHg (criteria 1), or higher than age-appropriate calculated value for P (A-a) O2 (criteria 2).

RESULTS

A total of 42 children in BA group and 62 in the non-BA CLD group were included. Using the criteria 1, the prevalence of HPS was 42.3%: 57.1% in the BA group and 32.2% in the CLD group, whereas using criteria 2, the prevalence was 48.1%: 61.9% in the BA group and 38.7% in the CLD group. Criteria 2 diagnosed 6 additional patients with HPS compared to criteria 1 (P value 0.405). BA subjects had higher risk (2.9-3 folds) of developing HPS compared to other CLDs.

CONCLUSION

There is high prevalence of HPS in pediatric liver disease subjects. Age-appropriate formula for HPS diagnosis may be better applicable in pediatric population. BA subjects have a higher risk of developing HPS compared to other CLDs overall, irrespective of the severity of liver disease and/or portal hypertension.

Natural history, risk factors, and outcome of hepatopulmonary syndrome in pediatric liver diseases

BACKGROUND

Limited pediatric literature is available regarding hepatopulmonary syndrome (HPS) especially in subjects with biliary atresia (BA) despite its proven prognostic significance. Thus, we aimed to study the natural history, risk factors, and outcome of HPS in BA and other chronic liver disease (CLD) subjects.

METHODS

All children (BA and other non-BA CLDs) older than 6 months of age were included in the study. HPS was diagnosed on the basis of standard international criteria. Also, fractional exhaled nitric oxide (FeNO) was measured at baseline.

RESULTS

During the study period from January 2017 to December 2018, there were 42 children in BA and 62 in the CLD group. The overall prevalence of HPS was 42.3%: 57.1% in the BA group and 32.2% in the CLD group. Median age at HPS diagnosis was 14.4 months and 90 months in the BA and non-BA CLD groups, respectively. By the end of study period, the prevalence of HPS in the BA group further increased to 73.8% at 0.7% per month. Lower serum albumin (p < 0.05) in BA and higher splenic Z scores (p 0.013) in other CLDs were found to be significant risk factors for HPS. FeNO measurement did not reach diagnostic significance.

CONCLUSION

Prevalence of HPS is higher and also develops at an earlier age in the BA group compared to other CLDs. Also, risk of HPS development increases with increasing disease duration in BA. Lower serum albumin in BA and higher splenic Z scores in other CLDs may predict risk for HPS development.

Prevalence and characteristics of hepatopulmonary syndrome in children with cirrhosis in southern Brazil

BACKGROUND

Hepatopulmonary syndrome (HPS) is defined as a triad characterized by arterial deoxygenation, intrapulmonary vascular dilatations (IPVDs), and liver disorder. The aims of this study were to assess the prevalence of HPS in children with cirrhosis, the clinical characteristics of patients with HPS, and the tests used for the diagnosis of IPVD.

PATIENTS AND METHODS

This was a prospective, cross-sectional study of 40 children with cirrhosis (median age: 44 months). Investigations of HPS included arterial blood gas analysis, contrast-enhanced transthoracic echocardiography (CE-TTE), and perfusion lung scanning using technetium-99m-labeled macroaggregated albumin (Tc-MMA). Patients' clinical characteristics (age, etiology of cirrhosis, and severity of hepatopathy) were assessed. HPS was defined as liver disease; alveolar-arterial oxygen gradient of at least 15 mmHg and/or partial pressure of arterial oxygen less than 80 mmHg; and detection of IPVD by CE-TTE or Tc-MMA scanning. Statistical significance was indicated by a P value less than 0.05.

RESULTS

The prevalence of HPS was 42.5% (17/40). Eight patients had moderate HPS (47%) and two patients had severe HPS (12%). In bivariate analysis, biliary atresia (P=0.033) and median age (10 months; P=0.005) were associated with HPS. In multivariate analysis, only age remained statistically significant (prevalence ratio=0.99; 95% confidence interval=0.98-0.99; P=0.010). Sixteen patients with HPS had IPVD detected by CE-TTE (94.1%) and six patients had IPVD detected by Tc-MMA scanning (35.3%), with no significant agreement between these methods (κ=-0.12; P=0.163).

CONCLUSION

HPS is a common complication of cirrhosis in children. A combination of clinical and imaging criteria should be used to diagnose HPS.

Cirrhosis and Portal Hypertension in the Pediatric Population

Cirrhosis is a complex process in which the architecture of the liver is replaced by structurally abnormal nodules due to cirrhosis. Cirrhosis frequently leads to the development of portal hypertension. In children, portal hypertension may be caused by a wide range of etiologies, including extrahepatic portal vein obstruction, biliary atresia, alpha 1 antitrypsin deficiency, and autoimmune hepatitis. Gastroesophageal varices and ascites are two of the complications of portal hypertension likely to cause morbidity and mortality. This review also discusses extrahepatic manifestations of portal hypertension and treatment options.

Differential diagnosis of hepatopulmonary syndrome (HPS): Portopulmonary hypertension (PPH) and hereditary hemorrhagic telangiectasia (HHT)

Hepatopulmonary syndrome (HPS) is a severe complication of advanced liver disease associated with an extremely poor prognosis. HPS is diagnosed in 4-47% of patients with cirrhosis and in 15-20% of candidates for liver transplantation. In addition, severe hypoxia is associated with a high risk of complications of liver transplantation (a 30% chance during the first 90 days) and increases the gap between transplantation and improving arterial oxygenation. The pathogenesis of HPS is not fully understood, and no effective pharmacological treatment has been developed yet. Currently, the treatment of choice for HPS is orthotopic liver transplantation. Non-specific clinical criteria and the lack of standardized diagnostic criteria for determining HPS can lead to diagnostic errors. Portopulmonary hypertension and hereditary hemorrhagic telangiectasia, also known as Osler-Weber-Rendu syndrome, are pulmonary complications of liver disease which should be differentially diagnosed from HPS.

Noncirrhotic Portal Fibrosis in Pediatric Population

OBJECTIVES

Noncirrhotic portal fibrosis (NCPF) has been classically described as a disease of young to middle age with limited literature regarding its occurrence, onset, or clinical presentation in children. We hereby present a series of 19 patients diagnosed and managed as NCPF in pediatric age group.

METHODS

A retrospective review of all the patients presenting to the pediatric hepatology department (age <18 years) and diagnosed as NCPF was done and data were evaluated.

RESULTS

A total of 19 patients were diagnosed as NCPF with median age at onset of symptoms and diagnosis as 10 years and 13.8 years respectively. Majority presented with left upper quadrant discomfort or mass. Laboratory parameters showed hypersplenism in majority with preserved liver synthetic functions. Median values for hepatic venous pressure gradient and liver stiffness measurement were 13.5 mmHg and 10.6 kPa, respectively. Classical hepatic histopathological features seen were maintained lobular architecture, atretic portal tracts, approximation of portal-portal and portal-central areas, and aberrant peripheral portal channels. During follow-up, majority of the patients did not show disease progression.

CONCLUSIONS

NCPF is not an uncommon entity in pediatric population with age of onset in early second decade. Hepatic histopathology must be used to exclude cirrhosis and to confirm the diagnosis. Hepatic venous pressure gradient and liver stiffness measurement values, in some cases, may overlap with those in patients with cirrhosis and may not be diagnostic in isolation. Any patient presenting with evidence of portal hypertension with preserved hepatic functions, irrespective of the age, should be evaluated for possible NCPF.

Hepatopulmonary syndrome is a frequent cause of dyspnea in the short telomere disorders

BACKGROUND

Telomere syndromes have their most common manifestation in idiopathic pulmonary fibrosis and emphysema. The short telomere defect in these patients may manifest systemically as bone marrow failure and liver disease. We sought to understand the causes of dyspnea in telomerase and telomere gene mutation carriers who have no parenchymal lung disease.

METHODS

Clinical and pathologic data were reviewed as part of a Johns Hopkins-based natural history study of short telomere syndromes including dyskeratosis congenita.

RESULTS

Hepatopulmonary syndrome (HPS) was diagnosed in nine of 42 cases (21%). Their age at presentation was significantly younger than that of cases initially presenting with pulmonary fibrosis and emphysema (median, 25 years vs 55 years; P < .001). Cases had evidence of intra- and extrapulmonary arteriovascular malformations that caused shunt physiology. Nodular regenerative hyperplasia was the most frequent histopathologic abnormality, and it was seen in the absence of cirrhosis. Dyspnea and portal hypertension were progressive, and the median time to death or liver transplantation was 6 years (range, 4-10 years; n = 6). In cases that underwent liver transplantation, dyspnea and hypoxia improved, but pulmonary fibrosis subsequently developed.

CONCLUSIONS

This report identifies HPS as a frequent cause of dyspnea in telomerase and telomere gene mutation carriers. While it usually precedes the development of parenchymal lung disease, HPS may also co-occur with pulmonary fibrosis and emphysema. Recognizing this genetic diagnosis is critical for management, especially in the lung and liver transplantation setting.

Transplantation in autosomal recessive polycystic kidney disease: liver and/or kidney?

Autosomal recessive polycystic kidney disease (ARPKD) is characterized by enlarged kidneys with dilated collecting ducts and congenital hepatic fibrosis. There is a variable rate of progression of kidney and liver disease. Portal hypertension and Caroli's disease occur from liver involvement that contributes to morbidity and mortality. Approximately 40 % of patients have a severe disease phenotype leading to rapid onset of end-stage kidney disease (ESKD) and signs of portal hypertension and the rest may have predominant involvement of either the kidney or liver. It is important for the physician to establish the extent of organ involvement before deciding on the ultimate plan of management, especially when transplantation is required. Isolated renal transplantation can be considered when liver involvement is minimal. If hepatobiliary disease is prominent, and kidney function is preserved, management options are based on individual characteristics. In the presence of significant liver disease and ESKD, consideration should be given to combined liver kidney transplantation, which can be beneficial in eliminating the consequences of both kidney and liver disease. However, this is a complex surgical procedure that needs to be performed at experienced transplant centers. Improvement in surgical techniques has considerably improved short-term graft survival with the added advantage of the liver offering immunologic protection to the kidney allograft.

Hepatopulmonary Syndrome in children: a comparative study of non-cirrhotic vs. cirrhotic portal hypertension

BACKGROUND & AIMS

Hepatopulmonary syndrome in children has not been extensively studied particularly in different subsets of portal hypertension. We prospectively studied hepatopulmonary syndrome in children with cirrhosis and extrahepatic portal venous obstruction. Their comparison might shed light on the pathogenesis of hepatopulmonary syndrome.

METHODS

Between 1 to 18 years of age, 135 children with portal hypertension (cirrhosis 35, extrahepatic portal venous obstruction 100) were studied. Hepatopulmonary syndrome was diagnosed by the presence intrapulmonary shunt using transthoracic contrast echocardiography and hypoxia/orthodeoxia (in arterial blood gas examination). Comparative analyses were done for both the groups, and also intra- and intergroups with and without hepatopulmonary syndrome.

RESULT

Of 135 children, hepatopulmonary syndrome occurred more frequently in cirrhosis (40%) than extrahepatic portal venous obstruction (13%) (P = 0.01). Cirrhotics with hepatopulmonary syndrome were symptomatic (85% vs. 14%, P < 0.001) and had longer disease duration [16(1-120) months vs. 28 (1-168) months, P = 0.01] as compared to cirrhotics without hepatopulmonary syndrome. Prevalence of hepatopulmonary syndrome among cirrhotics did not correlate with the severity of liver disease as assessed by both paediatric end-stage liver disease score and Child-Turcotte-Pugh score. Patients with extrahepatic portal venous obstruction and hepatopulmonary syndrome remain asymptomatic manifesting with clubbing alone (38%).

CONCLUSIONS

Hepatopulmonary syndrome occurs more frequently in cirrhosis, a majority being symptomatic with more severity in comparison to extrahepatic portal venous obstruction having no symptoms and less severity. There seems to be a role of liver dysfunction besides portal hypertension as an added factor in the pathogenesis of hepatopulmonary syndrome.

Cirrhosis in children and adolescents: An overview

Several conditions, especially chronic liver diseases, can lead to cirrhosis in children and adolescents. Most cases in clinical practice are caused by similar etiologies. In infants, cirrhosis is most often caused by biliary atresia and genetic-metabolic diseases, while in older children, it tends to result from autoimmune hepatitis, Wilson's disease, alpha-1-antitrypsin deficiency and primary sclerosing cholangitis. The symptoms of cirrhosis in children and adolescents are similar to those of adults. However, in pediatric patients, the first sign of cirrhosis is often poor weight gain. The complications of pediatric cirrhosis are similar to those observed in adult patients, and include gastrointestinal bleeding caused by gastroesophageal varices, ascites and spontaneous bacterial peritonitis. In pediatric patients, special attention should be paid to the nutritional alterations caused by cirrhosis, since children and adolescents have higher nutritional requirements for growth and development. Children and adolescents with chronic cholestasis are at risk for several nutritional deficiencies. Malnutrition can have severe consequences for both pre- and post-liver transplant patients. The treatment of cirrhosis-induced portal hypertension in children and adolescents is mostly based on methods developed for adults. The present article will review the diagnostic and differential diagnostic aspects of end-stage liver disease in children, as well as the major treatment options for this condition.

Refractory hypoxemia caused by hepatopulmonary syndrome: a case report

Introduction

Hepatopulmonary syndrome is a clinical syndrome that can affect patients of all ages with liver disease and is more common in children with biliary atresia. Contrast echocardiography is the test of choice to diagnose the presence of intrapulmonary vascular dilatation. The established treatment for hepatopulmonary syndrome is liver transplantation.

Case presentation

We present the case of an 8-month-old Caucasian baby boy with a history of biliary atresia, polysplenia, and interrupted inferior vena cava who presented with hypoxemia and cyanosis that progressed rapidly. A chest computed tomography angiogram revealed significant dilatation of the pulmonary vasculature, prompting further evaluation and diagnosis of hepatopulmonary syndrome with contrast echocardiography. He was maintained on a milrinone infusion while awaiting liver transplantation. His hypoxemia improved slowly following liver transplantation, requiring tracheostomy and prolonged ventilator dependence.

Conclusions

Hepatopulmonary syndrome should be included in the differential for progressive hypoxemia in children with liver disease, particularly those with biliary atresia. Imaging with chest computed tomography angiogram and contrast echocardiography should be considered in cases of unexplained refractory hypoxemia.

Intrapulmonary vascular dilatation evaluated by 99mTc-MAA scintigraphy and its association with portal hypertension in schistosomiasis

Background

Portal hypertension is responsible for various complications in patients with schistosomiasis, among them intrapulmonary vascular dilations (IPVD). In cirrhotic patients the presence of IPVD is a sign of poor prognosis, but in patients with hepatosplenic schistosomiasis (HSS) there are no studies assessing the significance of this change. The aim of this study was to evaluate the occurrence of IPVD through ^99mTc-MAA scintigraphy in patients with HSS and its relationship with clinical, laboratory, endoscopic and ultrasound parameters.

Methods

Cross-sectional study evaluating 51 patients with HSS. Patients were diagnosed with IPVD when the brain uptake of ^99mTc-MAA was higher than 6%. Subsequently, they were divided according to presence (G1) or absence (G2) of IPVD and variables were compared between groups.

Results

Overall, 51 patients with mean age of 56±12 years were assessed. IPVD was observed in 31 patients (60%). There was no statistically significant differences between groups when clinical, laboratory and endoscopic parameters were compared. Regarding ultrasound parameters, the splenic vein diameter was smaller in G1 (0.9±0.3 cm) compared to G2 (1.2±0.4 cm), p = 0.029.

Conclusion

In patients with HSS, the occurrence of IPVD by ^99mTc-MAA scintigraphy was high and was associated with lower splenic vein diameter, which can be a mechanism of vascular protection against portal hypertension. However, more studies are needed to determine the clinical significance of the early diagnosis and natural evolution of IPVD in this population.

Intrapulmonary vascular dilatation (IPVD) is the key event in development of hepatopulmonary syndrome, an arterial oxygenation defect in patients with portal hypertension. IPVD diagnosis can be made by EchoDopplercardiography or ^99mTc-macroaggregated albumin scintigraphy (^99mTc-MAA), and ethiopatogeny is still unknown. In Northeastern Brazil, hepatosplenic schistossomiasis (HSS) is the main cause of portal hypertension. In cirrhotics, the presence of IPVD influences survival and candidacy for liver transplantation, however, in HSS patients, IPVD has been poorly studied, specially using lung perfusion scan with ^99mTc-MAA. Some authors believe that IPVD is common in HSS and in the existence of differences in indirect portal hypertension parameters between patients with and without IPVD. All patients were distributed into two groups according to presence or not of IPVD, and laboratorial, endoscopy and ultrasound tests were perfomed. Occurrence of IPVD was high and was associated with lower splenic vein diameter, which can be a vascular protection mechanism against portal hypertension status.

Hepatopulmonary syndrome

PURPOSE OF REVIEW

To discuss the advances in the understanding of the pathophysiology of experimental and human hepatopulmonary syndrome (HPS) and in the management of HPS, particularly regarding liver transplantation.

RECENT FINDINGS

Advances have been made in defining the pathophysiology of HPS in experimental models as well as in human disease, including the role of endothelin-1, pulmonary monocytes, and angiogenesis. Additionally, the implications of the presence of HPS as it relates to prioritizing patients for liver transplantation and posttransplant outcomes will also be reviewed.

SUMMARY

Mechanisms of disease continue to be defined in HPS, providing potential targets for pharmacologic intervention. Outcomes after liver transplantation are also becoming clearer, including the management of HPS with severe hypoxemia.

Pathophysiology of lung injury induced by common bile duct ligation in mice

Background

Liver dysfunction and cirrhosis affect vasculature in several organ systems and cause impairment of organ functions, thereby increasing morbidity and mortality. Establishment of a mouse model of hepatopulmonary syndrome (HPS) would provide greater insights into the genetic basis of the disease. Our objectives were to establish a mouse model of lung injury after common bile duct ligation (CBDL) and to investigate pulmonary pathogenesis for application in future therapeutic approaches.

Methods

Eight-week-old Balb/c mice were subjected to CBDL. Immunohistochemical analyses and real-time quantitative reverse transcriptional polymerase chain reaction were performed on pulmonary tissues. The presence of HPS markers was detected by western blot and microarray analyses.

Results

We observed extensive proliferation of CD31-positive pulmonary vascular endothelial cells at 2 weeks after CBDL and identified 10 upregulated and 9 down-regulated proteins that were associated with angiogenesis. TNF-α and MMP-9 were highly expressed at 3 weeks after CBDL and were less expressed in the lungs of the control group.

Conclusions

We constructed a mouse lung injury model by using CBDL. Contrary to our expectation, lung pathology in our mouse model exhibited differences from that of rat models, and the mechanisms responsible for these differences are unknown. This phenomenon may be explained by contrasting processes related to TNF induction of angiogenic signaling pathways in the inflammatory phase. Thus, we suggest that our mouse model can be applied to pulmonary pathological analyses in the inflammatory phase, i.e., to systemic inflammatory response syndrome, acute lung injury, and multiple organ dysfunction syndrome.

Cirrhosis and hepatopulmonary syndrome

Hepatopulmonary syndrome (HPS) is characterized as a triad: liver disease, intrapulmonary vascular dilatation and arterial hypoxemia. HPS is reported to be present in 4% to 32% of adult patients with end-stage liver disease and in 9%-20% of children. The pathogenesis of HPS has not been clearly identified. Portal hypertension causes impairment in the perfusion of the bowel and increases the enteral translocation of Gram (-) bacteria and endotoxins. This stimulates the release of vasoactive mediators, such as tumor necrosis factor-alpha, heme oxygenase-derived carbon monoxide and nitric oxide. Genetic alterations have not been associated with this syndrome yet; however, cytokines and chemokines have been suggested to play a role. Recently, it was reported that cumulated monocytes lead to the activation of vascular endothelial growth factor-dependent signaling pathways and pulmonary angiogenesis, which plays an important role in HPS pathogenesis. At present, the most effective and only radical treatment is a liver transplant (LT). Cirrhotic patients who are on the waiting list for an LT have a shorter survival period if they develop HPS. Therefore, it is suggested that all cirrhotic cases should be followed closely for HPS and they should have priority in the waiting list.

Pulse oximetry is insufficient for timely diagnosis of hepatopulmonary syndrome in children with liver cirrhosis

OBJECTIVE

To prospectively investigate the prevalence of hepatopulmonary syndrome (HPS), the importance of pulse oximetry in diagnosing HPS, and the longitudinal course after liver transplantation in children with cirrhosis referred for liver transplantation.

STUDY DESIGN

Fifty-six patients aged 1-17 years (mean age, 4.6 ± 5.0 years) with liver cirrhosis were screened for HPS by hyperemic capillary blood gas (CBG) analysis and contrast-enhanced transthoracic echocardiography. Eleven patients were excluded owing to conditions that can produce cardiopulmonary dysfunction, including 5 with cystic fibrosis, 1 with pulmonary arterial hypertension, and 5 with an intracardial shunt. HPS was classified in accordance with the European Respiratory Society Task Force criteria on pulmonary-hepatic disorders. Patient groups were compared for biochemical and clinical characteristics.

RESULTS

Eighteen children (40%) with cirrhosis were intrapulmonary vasodilatation (IPVD)-positive and had a pulse oximetry oxygen saturation level >98%. Two of these patients (11%) exhibited moderate HPS with an elevated alveolar arterial oxygen gradient >15 mm Hg and PaO2 <70 mm Hg; they died before undergoing liver transplantation. The sensitivity and specificity of CBG analysis for detecting elevated alveolar arterial oxygen gradient in children with IPVD was 94% and 53%, respectively. HPS was associated with late hepatoportoenterostomy (P < .04). Liver transplantation led to resolution of HPS in all patients.

CONCLUSION

IPVD is frequent in children with liver cirrhosis (40%). Pulse oximetry is insufficient for timely HPS diagnosis. Pathological CBG analysis data indicate IPVD in the majority of cases, but are imprecise in children aged <2 years. Contrast-enhanced transthoracic echocardiography and CBG analysis are recommended for evaluation of HPS in children with cirrhosis, regardless of liver synthesis capacity and clinical chemistry data.