Associations of Liver Stiffness Measured by Ultrasound Shear-Wave Elastography With Portal Hypertension and Circulatory Failure in Individuals With Fontan Circulation.

Background: The Fontan operation palliates single-ventricle congenital heart disease but causes hepatic congestion with associated progressive hepatic fibrosis. Objective: To evaluate associations between liver stiffness measured using ultrasound shear-wave elastography (SWE) in patients with Fontan palliation and occurrence of portal hypertension and Fontan circulatory failure during follow-up. Methods: This retrospective study included 119 individuals ≥10 years old (median age, 19.1 years; 61 female, 58 male) with Fontan circulation who underwent liver ultrasound with 2D SWE from January 1, 2015, to January 1, 2022 and had ≥1 year of clinical follow-up (unless experiencing earlier outcome-related events). Median liver stiffness from initial ultrasound was documented. VAST (varices, ascites, splenomegaly, and thrombocytopenia) scores (range, 0-4) were determined as a marker of portal hypertension on initial ultrasound and ≥1-year follow-up imaging (ultrasound, CT, or MRI). Composite clinical outcome for Fontan circulatory failure (death, mechanical circulatory support, cardiac transplantation, or unexpected Fontan-related hospitalization) was assessed. Analysis included Wilcoxon rank-sum test, logistic regression analysis with stepwise variable selection, and ROC analysis. Results: Median initial liver stiffness was 2.22 m/s. Median initial VAST score was 0 (IQR: 0-1); median follow-up VAST score was 1 (IQR: 0-2) (p=.004). Fontan circulatory failure occurred in 37/119 (31%) patients (median follow-up, 3.4 years). Initial liver stiffness was higher in patients with follow-up VAST score ≥1 (2.37 m/s) than follow-up VAST score 0 (2.08 m/s) (p=.005), and in patients with (2.43 m/s) than without (2.10 m/s) Fontan circulatory failure at follow-up (p<.001). Initial liver stiffness was the only significant independent predictor of Fontan circulatory failure (OR=3.76; p<.001); age, sex, Fontan operation type, dominant ventricular morphology, and initial VAST score were not independent predictors. Initial liver stiffness had AUC of 0.70 (sensitivity 79%, specificity 57%; threshold, >2.11 m/s) for predicting follow-up VAST score ≥1, and 0.74 (sensitivity 84%, specificity 52%; threshold, >2.12 m/s) for predicting Fontan circulatory failure. Conclusion: In patients with Fontan circulation, increased initial liver stiffness was associated with portal hypertension and circulatory failure during follow-up, although had moderate performance in predicting these outcomes. Clinical Impact: Ultrasound SWE may play a role in post-Fontan surveillance, supporting tailored medical and surgical care.