Liver Nodules after the Fontan Operation: Role of Magnetic Resonance Elastography

Abstract

H epatic dysfunction after the Fontan operation runs an indolent course. Extracardiac sequelae arising from long-standing supraphysiologic right-sided heart pressure or flow-related abnormalities are frequently encountered and contribute substantially to morbidity and death in these patients. Patients who have had the Fontan operation are at increased risk of developing liver disease. Eventually these patients can develop cirrhosis and its related sequelae, including hepatocellular carcinoma. The length of time for the evolution of these hepatic changes is unclear, and the severity of liver dysfunction is often underestimated on the basis of serum biochemical testing. The conventional standard for the diagnosis and staging of liver fibrosis is percutaneous biopsy. Liver biopsy is invasive and expensive, has poor patient acceptance, is prone to interobserver variability and sampling errors, and has a complication rate of 3%, with a mortality rate of 0.03%. 1Liver dysfunction often precedes laboratory or ultrasonographic detection of pathologic conditions. Early cirrhosis can be missed, and rare cases of hepatocellular carcinoma have been reported.2 Moreover, there is no standard means of evaluating patients for hepatic dysfunction after the Fontan procedure. Magnetic resonance elastography (MRE) has emerged as an advanced screening tool for preclinical detection of hepatic fibrosis and cirrhosis. Multiple studies have shown a strong correlation between MRE-measured hepatic stiffness and the stage of fibrosis at histology. The emerging literature indicates that MRE can serve as a safe, less expensive, and more accurate alternative to invasive liver biopsy. 3The MRE is performed with use of a mechanical acoustic driver and can be performed in conjunction with cardiac magnetic resonance imaging (MRI). Mean liver stiffness is calculated on automatically generated stiffness maps, in units known as kilopascals (kPa). We describe the case of a patient in whom liver nodules suspect for malignancy developed 18 years after the Fontan operation. She also had elevated tumor markers. This report describes the challenges in the diagnosis of hepatic dysfunction and the role of MRE in patients after a Fontan operation. Case ReportA 21-year-old nursing student who had undergone a fenestrated extracardiac Fontan procedure at 3 years of age presented for her annual cardiac follow-up examination. She was born with pulmonary atresia with intact ventricular septum and a hypoplastic monopartite right ventricle without evidence of right-ventricular-dependent coronary circulation. Her previous surgical procedures had included a right modified BlalockTaussig shunt (at 5 days of age), a right bidirectional cavopulmonary anastomosis, and a Fontan fenestration purse-string closure.

Liver disease secondary to congenital heart disease in children

“…The diagnostic accuracy of the FibroScan system for hepatic fibrosis has been validated in chronic viral hepatitis and nonalcoholic fatty liver disease. However, evidence of the utility of ultrasound-based elastography for cardiac hepatopathy remains insufficient [23,93,[103][104][105][131][132][133][134][135][136][137][138][139][140]. Because ultrasound-based elastography cannot differentiate blood from fibrosis, congestion influences the liver stiffness assessed by elastography.…”