Epidemiology of Fontan-associated liver disease in Japan: Results from a nationwide survey in 2021

AimAlthough the Fontan procedure has improved the survival of patients with single-ventricle heart disease, the long-term consequences of the procedure have been a concern. This study aimed to explore the patients' postoperative clinical characteristics, including a diagnosis of Fontan-associated liver disease (FALD).MethodsA nationwide Japanese epidemiological survey of post-Fontan patients was undertaken in 2021. The survey targets were selected from all departments of pediatrics, pediatric surgery, cardiology, cardiovascular surgery, and gastroenterology using stratified random sampling by the number of beds. Each department was asked to complete a mail-back questionnaire on the numbers of patients and their clinical characteristics. The diagnosis of FALD was made by each attending physician.ResultsThe estimated number of post-Fontan patients was 7810 (95% confidence interval, 5430-10 200) in 2020, with a period prevalence of 61.9 per million. During the follow-up of 13.8 years after the Fontan procedure, 40% of patients were diagnosed with FALD. An elevated gamma-glutamyl transpeptidase level was the most common finding leading to the FALD diagnosis (41%), and 45% of the patients also showed liver fibrosis. Compared with non-FALD patients, FALD patients were older, had longer duration since the Fontan procedure, and had more severe cardiac or liver conditions. However, more than half of the non-FALD patients had elevated liver enzyme levels, suggesting underestimation of the number of FALD patients.ConclusionsIn 2020, approximately 40% of post-Fontan patients underwent follow-up with a diagnosis of FALD, although the lack of established diagnostic criteria for FALD could affect the reported prevalence of FALD. In Japan, the number of post-Fontan procedure patients was estimated to be 7810 in 2020, and 3120 (40%) of these patients were diagnosed with Fontan-associated liver disease (FALD) during the median follow-up of 13.8 years after the procedure. The most common sign leading to the diagnosis of FALD other than liver fibrosis was an elevated gamma-glutamyl transpeptidase level. More than half of the patients without a diagnosis of FALD had increased liver enzymes, suggesting that the number of patients with FALD was underestimated. image