Abstract 15299: Association Between Change in Liver Stiffness and Adverse Outcomes in Individuals With Fontan Circulation

Introduction: Fontan-associated liver disease (FALD) contributes to adverse outcomes late after the Fontan procedure. Elevated Magnetic Resonance Elastography-derived Liver Stiffness (MRE-LS) is associated with higher Fontan pressure and Fontan circulatory failure (FCF). How MRE-LS changes over time and if it can predict adverse outcomes has not been studied. Methods: Single center retrospective study of individuals >10 years-old post-Fontan with >1 MRE-LS study between 2010-2020. Absolute change in liver stiffness (shear modulus in kilopascals, kPa) was defined as the difference between first and second MRE-LS measures. Demographic and clinical data were collected. FCF was defined as the composite outcome of death, transplant, VAD placement, or unscheduled cardiac hospitalization following index MRE. To compare the effect of magnitude of change in liver stiffness, patients were ordered from lowest negative to highest positive (Quartile 1-4) change. Results: 77 individuals were included (mean age at first MRI 19.9±6.7 years, 47% female). Baseline MRE-LS was 4.4±1.0 kPa, follow-up MRE-LS was 4.1±1.1 kPa with mean time between MRE examinations of 46±27 months. The median annual change in MRE-LS was -0.06 (IQR -0.2-0.05) kPa/year. There was no association between change in MRE-LS and age ventricular dysfunction, or Fontan pressure. FCF occurred in 18 (23%) individuals, and those with FCF had a greater increase in MRE-LS (0.12±0.83 vs -0.42±0.96 kPa, p=0.04, Figure). Conclusions: MRE-LS remains stable over short-term follow-up in most individuals with Fontan circulation. However, those with greater positive change in liver stiffness were more likely to experience adverse outcomes. An increase in MRE-LS is a potential non-invasive biomarker of clinical decompensation. Figure: Probability of endpoint-free survival based on the change in liver stiffness quartiles (4 = largest increase in MRE-LS). Tick marks on curves indicate patients censored.