Direct hyperbilirubinemia in infants with congenital heart disease

Fontan-Associated Liver Disease: A Review

Fontan-associated liver disease (FALD) is a chronic complication of the Fontan procedure, a palliative surgery for patients with congenital heart disease that results in a single-ventricle circulation. The success of the Fontan procedure has led to a growing population of post-Fontan patients living well into adulthood. For this population, FALD is a major cause of morbidity and mortality. It encompasses a spectrum of hepatic abnormalities, ranging from mild fibrosis to cirrhosis and hepatocellular carcinoma. The pathophysiology of FALD is multifactorial, involving hemodynamic and inflammatory factors. The diagnosis and monitoring of FALD present many challenges. Conventional noninvasive tests that use liver stiffness as a surrogate marker of fibrosis are unreliable in FALD, where liver stiffness is also a result of congestion due to the Fontan circulation. Even invasive tissue sampling is inconsistent due to the patchy distribution of fibrosis. FALD is also associated with both benign and malignant liver lesions, which may exhibit similar imaging features. There is therefore a need for validated diagnostic and surveillance protocols to address these challenges. The definitive treatment of end-stage FALD is also a subject of controversy. Both isolated heart transplantation and combined heart-liver transplantation have been employed, with the latter becoming increasingly preferred in the US. This article reviews the current literature on the epidemiology, pathophysiology, diagnosis, and management of FALD, and highlights knowledge gaps that require further research.

Conjugated hyperbilirubinemia is associated with increased morbidity and mortality after neonatal heart surgery

BACKGROUND

Cholestasis characterised by conjugated hyperbilirubinemia is a marker of hepatobiliary dysfunction following neonatal cardiac surgery. We aimed to characterise the incidence of conjugated hyperbilirubinemia following neonatal heart surgery and examine the effect of conjugated hyperbilirubinemia on post-operative morbidity and mortality.

METHODS

This was a retrospective study of all neonates who underwent surgery for congenital heart disease (CHD) at our institution between 1/1/2010 and 12/31/2020. Patient- and surgery-specific data were abstracted from local registry data and review of the medical record. Conjugated hyperbilirubinemia was defined as perioperative maximum conjugated bilirubin level > 1 mg/dL. The primary outcome was in-hospital mortality. Survival analysis was conducted using the Kaplan-Meier survival function.

RESULTS

Conjugated hyperbilirubinemia occurred in 8.5% of patients during the study period. Neonates with conjugated hyperbilirubinemia were more likely to be of younger gestational age, lower birth weight, and non-Caucasian race (all p < 0.001). Patients with conjugated hyperbilirubinemia were more likely to have chromosomal and non-cardiac anomalies and require ECMO pre-operatively. In-hospital mortality among patients with conjugated hyperbilirubinemia was increased compared to those without (odds ratio 5.4). Post-operative complications including mechanical circulatory support, reoperation, prolonged ventilator dependence, and multi-system organ failure were more common with conjugated hyperbilirubinemia (all p < 0.04). Patients with higher levels of conjugated bilirubin had worst intermediate-term survival, with patients in the highest conjugated bilirubin group (>10 mg/dL) having a 1-year survival of only 6%.

CONCLUSIONS

Conjugated hyperbilirubinemia is associated with post-operative complications and worse survival following neonatal heart surgery. Cholestasis is more common in patients with chromosomal abnormalities and non-cardiac anomalies, but the underlying mechanisms have not been delineated.

Direct Bilirubin and Risk of Biliary Atresia

BACKGROUND

Early detection of biliary atresia (BA) is important for optimal treatment. Direct bilirubin (D-bil) levels are used for BA screening. In this study, we aimed to determine the sensitivity and specificity of elevated D-bil and the direct-to-total bilirubin (D/T) ratio for BA detection in high-risk infants.

METHODS

This retrospective, cross-sectional study was conducted in a tertiary medical center in Taiwan. Infants indicated for total bilirubin and D-bil measurements before age 60 days were included. The first bilirubin assessment was considered the test point. BA diagnosis was based on International Classification of Diseases, Ninth and Tenth Revision, codes 751.61 and Q44.0 to Q44.3, respectively.

RESULTS

Between January 2009 and December 2016, 4468 infants were enrolled, including 38 with BA. Among infants aged 3 to 60 days, a sensitivity of 100% (95% confidence interval, 90.3-100.0) was found for D-bil ≥1.0 mg/dL and either D-bil ≥1.0 mg/dL or D/T ratio ≥20%. However, D-bil ≥1.0 mg/dL had higher specificity (77.3% [76.0-78.5] vs 68.3% [66.8-69.7], respectively). In newborns aged <3 days, D-bil ≥0.5 mg/dL was considered a positive result, with a sensitivity of 50%. D-bil >0.45 mg/dL was a better cutoff point in receiver operating characteristic analysis, with a sensitivity and specificity of 100% (95% CI: 15.8-100) and 15.4% (95% CI, 11.8-19.7), respectively.

CONCLUSIONS

D-bil ≥1.0 mg/dL was better for BA detection than the D/T ratio in infants aged 3 to 60 days. For newborns aged <3 days, a more definitive cutoff point is required.

Direct hyperbilirubinemia and cholestasis in trisomy 13 and 18

Trisomy 13 and 18 are common chromosomal abnormalities that affect multiple organ systems. There is a paucity of published data, however, on the hepatic complications seen in these patient populations. One of the most common pathologic hepatobiliary issues seen in the newborn period is direct hyperbilirubinemia (DH). Thus, this study sought to estimate the incidence and evaluate possible etiologies of DH in neonates with trisomy 13 or 18. This retrospective cohort study included all infants admitted to our two neonatal intensive care units between 2012 and 2020 with the diagnosis of trisomy 13 or 18. DH is most commonly diagnosed as a direct bilirubin >1 mg/dl but a cutoff of >2 mg/dl is more specific for cholestasis, so both cutoffs were evaluated. Continuous data were compared using Fisher's exact test and categorical variables by the Mann-Whitney U test. Thirty-five patients met inclusion: 13 with trisomy 13 and 22 with trisomy 18. DH of >2 mg/dl was seen in seven (53.8%) patients with trisomy 13 and five (22.7%) with trisomy 18. Using a cutoff of >1 mg/dl, the rate of trisomy 13 was unchanged, but the rate in trisomy 18 increased to 9/22 (40.9%). There was a trend toward more DH in trisomy 13 patients (p = 0.079) versus trisomy 18 and higher rates in infants who received total parenteral nutrition (TPN) (50.0 vs. 13.3%, p = 0.026). The presence of cardiac or ultrasound-defined hepatobiliary abnormalities was not correlated with DH. Due to the high rates of DH in hospitalized neonates with trisomy 13 and 18, we recommend screening newborns with trisomy 13 or 18 for DH starting in the first week of life and continuing at least weekly until 4 weeks of life or until completion of TPN, whichever comes later. Future studies should further evaluate possible etiologies of DH in this population.

Fontan-Associated Liver Disease: Pathophysiology, Staging, and Management

Fontan-associated liver disease is the term used to encompass the disorders arising from abnormal hemodynamic alterations and systemic venous congestion after the Fontan procedure. The histological changes produced in the liver are similar but not equivalent to those seen in other forms of cardiac liver disease. While the natural history of this form of liver disease is poorly established, many Fontan patients ultimately develop portal hypertension-related complications such as ascites, esophageal varices, malnutrition, and encephalopathy. Fontan survivors also show an elevated risk of hepatocellular carcinoma. Adequate staging of the liver damage is essential to anticipate screening strategies and improve global management.

Cholestasis after very preterm birth was associated with adverse neonatal outcomes but no significant long-term liver disease: A population-based study

AIM

To describe outcome linked to neonatal cholestasis in a defined cohort of very preterm infants.

METHODS

Population-based retrospective case-control study of preterm infants, gestational age <30 weeks, surviving for 28 days, in Stockholm County. Cholestasis was defined as conjugated bilirubin ≥30 μmol/L exceeding 20% of total level at least twice and graded as high if exceeding 100 μmol/L. Cholestatic cases were matched on gestational week with two non-cholestatic controls.

RESULTS

The incidence rate of cholestasis was 37/250 (14.8%), with increasing rates in lower gestational weeks. Perinatal factors associated with cholestasis were pre-eclampsia and being born small for gestational age. Cholestatic infants had three times more bronchopulmonary dysplasia and eight times more retinopathy of prematurity. The mortality was 13.5% in cholestatic infants versus 2.7% in controls (P = .040). All deceased cholestatic infants had high-grade cholestasis. No surviving infants developed chronic liver disease by 10 years of age.

CONCLUSION

Cholestasis was common in very preterm infants and linked to disease severity and adverse outcome. Cholestasis may be an independent risk factor for bronchopulmonary dysplasia and retinopathy of prematurity and more severe cholestasis associated with increased mortality. Cholestasis was not associated with chronic liver disease later in childhood.

Risk factors and outcomes for hyperbilirubinaemia after heart surgery in children

INTRODUCTION

Liver dysfunction, associated with morbidity and mortality, is common in patients with CHD. We investigate risk factors for and outcomes of hyperbilirubinaemia in neonates and infants after cardiac surgery.

MATERIALS AND METHODS

In a retrospective analysis of neonates and infants undergoing cardiac surgery at our institution between January 2013 and December 2017, we identified those with post-operative conjugated hyperbilirubinaemia. We tested various demographic and surgical risk factors, and use of post-operative interventions, for an association with conjugated hyperbilirubinaemia. We also tested hyperbilirubinaemia for association with post-operative mortality and prolonged length of stay.

RESULTS

We identified 242 post-operative admissions, of which 45 (19%) had conjugated hyperbilirubinaemia. The average conjugated bilirubin level in this group was 2.0 mg/dl versus 0.3 mg/dl for peers without hyperbilirubinaemia. The post-operative use of both extracorporeal membrane oxygenation (OR 4.97, 95% CI 1.89-13.5, p = 0.001) and total parenteral nutrition (OR 2.98, 95% CI 1.34-7.17, p = 0.010) was associated with conjugated hyperbilirubinaemia. No demographic variable analysed was found to be a risk factor. Hyperbilirubinaemia was associated with higher odds of mortality (OR 3.74, 95% CI 2.69-13.8, p = 0.005) and prolonged length of stay (OR 2.87, 95% CI 2.02-7.97, p = 0.005), which were independent of other risk factors.

DISCUSSION

We identified the post-operative use of total parenteral nutrition and extracorporeal membrane oxygenation as risk factors for hyperbilirubinaemia. These patients were more likely to experience morbidity and mortality than control peers. As such, bilirubin may be marker for elevated risk of poor post-operative outcomes and should be more frequently measured after cardiac surgery.