Introduction:
Hepatic dysfunction is a well-known complication and is frequently referred to as Fontan-associated liver disease. The aim of the study is to assess liver dysfunction in children and adolescents with Fontan circulation.

Material and methods:
The study was an observational analytical study conducted on 30 patients who underwent Fontan operation more than 2 years before inclusion in the study and who were followed up at the Paediatric Cardiology Unit, Cairo University Children’s Hospital. All patients were subjected to echocardiography, laboratory investigations, abdominal ultrasound, and liver elastography.

Results:
The median patient age was 13 years (inter-quartile range [IQR] 10–16.32), and the median follow-up duration after the Fontan operation was 5 years (IQR 3.83–9). Global longitudinal strain was lower in 26 (86.7%), and the single ventricle ejection fraction was reduced in 23 (76.7%); however, no correlation was found with time interval since Fontan. None of the patients had ascites clinically or by ultrasound examination. Gamma-glutamyl transferase was elevated in 28 (93.33%), which was significantly higher in the systemic right ventricle group. Abdominal ultrasound revealed periportal enhancement in 6 (20%), which was significantly higher in the hepatitis C virus exposed group (p = 0.006). Superior mesenteric artery resistance index was decreased in 27 (90%), which was significantly lower in the systemic left ventricle group (p = 0.01). The liver stiffness values did not correlate with time interval since Fontan (p = 0.09).

Conclusions:
Liver disease is prevalent in Fontan patients. Non-invasive measures such as laboratory tests, ultrasound, and elastography should be implemented with consideration for hepatology consultation. Fontan-associated liver disease screening is important in the monitoring of Fontan patients.