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. The purpose of this study was to evaluate associations between liver stiffness measured using ultrasound (US) shear-wave elastography (SWE) in patients with Fontan palliation and the occurrence of portal hypertension and Fontan circulatory failure during follow- up. METHODS. This retrospective study included 119 individuals 10 years old or older (median age, 19.1 years; 61 female patients, 58 male patients) with Fontan circulation who underwent liver US with 2D SWE from January 1, 2015, to January 1, 2022, and had 1 year or more of clinical follow-up (unless experiencing earlier outcome-related events). Median liver stiffness from the initial US examination was documented. Varices, ascites, splenomegaly, and thrombocytopenia (VAST) scores (range, 0-4) were determined as a marker of portal hypertension on initial US examination and 1 year or more of follow-up imaging (US, CT, or MRI). Composite clinical outcome for Fontan circulatory failure (death, mechanical circulatory support, cardiac transplant, or unexpected Fontan circulation-related hospitalization) was assessed. Analysis included the 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 of 119 (31%) patients (median follow-up, 3.4 years). Initial liver stiffness was higher in patients with a follow-up VAST score of 1 or greater (2.37 m/s) than in those with a follow- up VAST score of 0 (2.08 m/s) (p =.005), and initial liver stiffness was higher in patients with (2.43 m/s) than without (2.10 m/s) Fontan circulatory failure during 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 an AUC of 0.70 (sensitivity, 79%; specificity, 57%; threshold, > 2.11 m/s) for predicting a follow-up VAST score of 1 or greater and an AUC of 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 it had moderate performance in predicting these outcomes. CLINICAL IMPACT. US SWE may play a role in post-Fontan surveillance, supporting tailored medical and surgical care.