Mild to Moderate Intrapulmonary Shunting in Pediatric Liver Transplantation: Is Screening Necessary?

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.

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.

Outcomes of 50 Cases of Pediatric Liver Transplantation for Intrapulmonary Shunt While Considering the Deteriorated Prognosis of Severe Intrapulmonary Shunt Patients

BACKGROUND

Intrapulmonary shunt (IPS) is recognized in 10% of chronic liver disease patients. Liver transplantation (LT) is associated with a high risk of morbidity and mortality in patients with IPS.

PATIENTS AND METHODS

Of 519 pediatric LT cases between November 2005 and October 2018, 50 patients with IPS were enrolled in this study. The patients were divided into 3 groups, according to the shunt ratio, calculated by scintigraphy: mild (15%-20%, n = 26), moderate (20%-40%, n = 19), and severe (> 40%, n = 5). We compared the patients' characteristics before LT and the outcomes of LT between these groups.

RESULTS

The major original disease resulting in LT in the mild and moderate groups was biliary atresia (73.1% and 52.6%, respectively), while that in the severe group was congenital portosystemic shunt (60%). The median ages at LT were 7.5, 6.1, and 8.3 years in the mild, moderate, and severe groups, respectively. All of the mild and moderate IPS patients lived; however, 3 patients with severe IPS (60.0%) died within 3 months. The shunt ratios of the mild and moderate IPS patients normalized within 2 years after LT, while the 2 surviving severe IPS patients showed a slight improvement. The autopsy findings of the lung in 1 deceased severe IPS patient showed medial hypertrophy and proliferation of intimal cells of the pulmonary arteries, suggesting a diagnosis of portopulmonary hypertension.

CONCLUSIONS

LT can be safely performed for mild and moderate IPS patients; however, LT for severe IPS patients should be carefully indicated because concomitant portopulmonary hypertension may be masked by IPS.