Abstract
BackgroundChildren with Fontan circulation are at risk of developing hepatic fibrosis/cirrhosis. Reliable noninvasive monitoring techniques are lacking or under development.ObjectiveTo investigate surrogate indicators of hepatic fibrosis in adolescents with Fontan circulation by evaluating hepatic magnetic resonance (MR) T1 mapping and extracellular volume fraction measurements compared to US shear-wave elastography.Materials and methodsWe analyzed hepatic native T1 times and extracellular volume fractions with modified Look-Locker inversion recovery. Liver stiffness was analyzed with shear-wave elastography. We compared results between 45 pediatric patients ages 16.7±0.6 years with Fontan circulation and 15 healthy controls ages 19.2±1.2 years. Measurements were correlated to clinical and hemodynamic data from cardiac catheterization.ResultsMR mapping was successful in 35/45 patients, revealing higher hepatic T1 times (774±44 ms) than in controls (632±52 ms; P<0.001) and higher extracellular volume fractions (47.4±5.0%) than in controls (34.6±3.8%; P<0.001). Liver stiffness was 1.91±0.13 m/s in patients vs. 1.20±0.10 m/s in controls (P<0.001). Native T1 times correlated with central venous pressures (r=0.5, P=0.007). Native T1 was not correlated with elastography in patients (r=0.2, P=0.1) or controls (r = −0.3, P=0.3). Extracellular volume fraction was correlated with elastography in patients (r=0.5, P=0.005) but not in controls (r=0.2, P=0.6).ConclusionIncreased hepatic MR relaxometry and shear-wave elastography values in adolescents with Fontan circulation suggested the presence of hepatic fibrosis or congestion. Central venous pressure was related to T1 times. Changes were detected differently with MR relaxometry and elastography; thus, these techniques should not be used interchangeably in monitoring hepatic fibrosis.
Highlights
Study participantsThe Fontan operation was introduced more than 40 years ago as a lifesaving treatment for univentricular-type heart defects
In the Fontan circulation, transpulmonary blood flow is driven by chronically elevated central venous pressure, which leads to end-organ complications on both visceral organs and lymphatic drainage [2, 3]
The craniocaudal spleen length was measured with magnetic resonance (MR); 11 patients had spleen lengths >13 cm and 5 had frank splenomegaly >14.5 cm (Table 2) [25]
Summary
The Fontan operation was introduced more than 40 years ago as a lifesaving treatment for univentricular-type heart defects. This procedure creates an artificial circulation with two serial capillary beds by connecting the caval veins to the pulmonary artery [1]. In adults, Fontanassociated liver disease, characterized by fibrosis/cirrhosis and increased cancer risk, is a major concern. The prevalence and impact of liver disease are less well explored [3,4,5]. Fontan circulation are at risk of developing hepatic fibrosis/cirrhosis. Reliable noninvasive monitoring techniques are lacking or under development
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