Fontan associated liver disease: Is elastography useful?

Introduction: Fontan associated liver disease (FALD), can manifest in the form of abnormal liver function tests to cirrhosis to hepato cellular carcinoma. Onset of liver disease in such patients can go unnoticed for years if only synthetic function of liver is looked at or till the clinical symptoms appear. Elastography using ultrasound has been advocated as a non-invasive tool that can measure the severity of hepatic stiffness and as an early indicator of FALD. Methods: We investigated the hepatic stiffness using shear wave elastography (SWE) and related factors in patients with a Fontan circulation. This study enrolled 104 patients with Fontan circulation who at the time of follow up underwent elastography. Correlation between laboratory tests, and SWE measured hepatic stiffness was evaluated. Results: Mean duration after the Fontan operation was 7.1 +/- 3.5 years. The mean value of hepatic stiffness in post Fontan patients (12.4 +/- 2.8 kPa) was higher than the normal (4.5 kPa). The average liver stiffness was comparable in patients who underwent primary Fontan (12.7 +/- 3.4 kPa) or staged Fontan (12.4 +/- 2.7 kPa) (p=.18). In the univariate analysis, the age at Fontan, duration post Fontan and time interval between Glenn and Fontan surgery had no significant correlation with SWE measured hepatic stiffness. Conclusion: Increased hepatic stiffness measured through shear wave elastography might just be reflecting higher venous pressures in such patients and the cut-offs used for viral hepatitis may not be applicable to single ventricle physiology patients. The role of increased venous pressure in hepatic stiffness needs to be confirmed by cardiac catheterization in such patients.