Fontan hepatic fibrosis and serial liver biopsies

Background: The value and timing of liver biopsy, as a component of monitoring Fontan-associated liver disease progression, is unknown. Objective: We compared liver total fibrosis scores (TFS) derived from post-Fontan patients who underwent an initial and subsequent transvenous hepatic biopsy. Methods: We identified post-Fontan patients who had transvenous hepatic biopsy during cardiac catheterization between January 2012 and September 2023. We selected those that had both an initial and subsequent study. We calculated a TFS (0-8) by summing the portal fibrosis scores (0-4) and the sinusoidal fibrosis scores (0-4). Results: We identified 181 patients, of which 56 underwent an initial and subsequent study. Of the 56, 33 (58.9) were male. The average time between studies was 5.2 +/- 1.5 years. The average age at biopsy 1 was 17.6 +/- 9.6 years and 23.9 +/- 9.8 years at biopsy 2 (p = .002), and the average Fontan duration at biopsy 1 was 14.0 +/- 8.1 years and 19.4 +/- 7.8 years at biopsy 2 (p = .0003). Overall, the average TFS at biopsy 1 was 2.6 +/- 1.4 and 2.7 +/- 1.5 at biopsy 2 (p = .56). However, for the 56 patients, 23 had an increase in TFS (average increase of 1.7), 15 had a decrease in TFS (average decrease of 1.8), and 18 had no change in TFS; further, there were no differences in average Fontan mean pressures between the first and second biopsy regardless of whether TFS increased, decreased or were unchanged. Conclusion: In a cohort of primarily young, stable Fontan patients, despite a significant five-year average interval between transvenous hepatic biopsies, we found no significant change in average TFS for the cohort as a whole. However, some patients demonstrated an increase, decrease, or no change in TFS between biopsies. Such differences could be related to hepatic fibrosis heterogenicity and subjective biopsy grading. To our knowledge, this is the largest cohort of post-Fontan patients who have undergone a comparison of liver fibrosis scoring between initial and subsequent liver biopsies.