4612. Fontan-Associated Liver Disease: Imaging the Adult Population
Authors * Denotes Presenting Author
  1. Ciara O Brien *; Joint Department of Medical Imaging/University Health Network/University of Toronto
  2. Stephanie Tan ; Joint Department of Medical Imaging/University Health Network/University of Toronto
The Fontan operation is a palliative procedure for patients with single ventricle congenital heart disease where the systemic venous return is directed into the pulmonary circulation. Fontan-associated liver disease (FALD) is a recognized disease of the liver in patients who have had a Fontan surgery and is a broad term encompassing hepatic parenchymal change, focal nodular hyperplasia (FNH) like nodules, liver fibrosis and cirrhosis. FALD is one of the major noncardiac causes of mortality in adult Fontan patients. It is reported that 43% of Fontan patients have evidence of advanced liver fibrosis 30 post surgery.

Materials and Methods:
Data were collected from the abdomen ultrasound (US) examinations, clinic visits, and cross-sectional images. Both abdominal ultrasound and clinical data were considered within twelve months of cross-sectional imaging. From a large cohort of 547 Fontan patients followed at the Adult Congenital Heart Diseases program at our institution from September 2015 until September 2022, 151 patients who were assessed with liver cross-sectional imaging (MRI or CT) and abdominal US within 12 months were included based on the imaging and clinical criteria of the study. Demographic and clinical data include the date of birth, sex, BMI, date of Fontan, and type of Fontan were documented. Liver scores were estimated using laboratory data. Data from the latest available CT or MRI were collected. The definition of liver cirrhosis was decided, and statistical analysis was performed.

The presence of either surface nodularity or lobar redistribution on US or CT/MRI were significantly associated with an increase in hepatic fibrosis. There was fair to moderate agreement between US and CT/MRI for features of cirrhosis. US had a similar detection rate for hepatic nodules and HCC as CT/MRI. There were 131 abdominal ultrasounds included and of these, a total of 99 patients (75.6%) met criteria for cirrhosis (defined as = 2 of surface nodularity, lobar redistribution, or heterogenous parenchyma). Eighty-five (65.4%) patients had surface nodularity, 95 (73.1%) had lobar redistribution, and 112 (85.5%) had heterogenous echotexture. On CT/MRI, 110 (84%) had surface nodularity, 114 (87%) had lobar redistribution, and 79 (60.3%) had heterogenous echotexture. There were 131 CT or MRI scans included, and of these, a total of 118 patients (90%) met criteria on CT/MRI for cirrhosis (defined as = 2 of surface nodularity, lobar redistribution, heterogenous parenchyma, or parenchymal reticulation). Of patients meeting criteria for cirrhosis on CT/MRI, 93 (78.8%) also met criteria for cirrhosis on US. Five patients had HCC in our population and 17 patients died.

This is one of the largest cohorts of adult Fontan patients reported in the literature, which assesses the relationship between imaging findings and clinical parameters. This is a relatively new disease for adult radiologists to investigate, and this study will provide a road map for surveillance and follow-up of this patient cohort as they transition from pediatric to adult services.