Transient Elastography May Identify Fontan Patients with Unfavorable Hemodynamics and Advanced Hepatic Fibrosis

2014 Congenital Heart Disease 9;5 (438-447)

Background: Transient elastography (TE) offers a noninvasive correlate with the degree of hepatic fibrosis. However, factors other than fibrosis affect liver stiffness. We sought to determine whether hepatic congestion related to hemodynamics in Fontan circulation influences liver stiffness measurement (LSM) assessed by TE. Methods: We studied 45 subjects with Fontan circulation undergoing cardiac catheterization with or without simultaneous liver biopsy. Subjects underwent TE within 5 days before catheterization. Clinical history, hemodynamic and biopsy data, and hepatic biomarkers were 12 collected. Five subjects who had previously undergone liver biopsy and TE were also included. Results: Median age was 13.1y (range 2.4-57.8); median time since Fontan was 9.9y (range 0.1-17 32.5). No subject had known hepatitis C. Mean LSM for the entire cohort was 21.4 ± 10.8 18 kPa. Univariate regression analysis using LSM as a continuous outcome variable shows 19 significant correlations with age (R=0.35, p=0.01), time since Fontan (R=0.41, p=0.003), 20 Fontan pressure (R=0.31, p=0.04), cardiac index (R=-0.33, p=0.03), pulmonary vascular 21 resistance (R=0.34, p=0.03), systemic arterial oxygen saturation (R=0.31, p=0.04), and 22 platelet count (R=-0.29, p=0.05). On multiple regression analysis, Fontan pressure (β=0.901, 23 p=0.03) and cardiac index (β=-2.703, p=0.02) were significant predictors of LSM with overall 24 model R2=0.206. Univariate analysis shows LSM to be associated with more severe 25 centrilobular fibrosis (p=0.05). Conclusions: Higher LSM is associated with unfavorable Fontan hemodynamics and advanced 1 centrilobular hepatic fibrosis. TE may be a useful tool for identifying Fontan patients who 2 warrant invasive testing.