Hepatic Vein Saturation in Fontan Surveillance Cardiac Catheterizations

Abstract Staged palliation of single ventricle congenital heart disease culminating in complete cavo-pulmonary anastomosis (“Fontan”) is life preserving but is associated with long term morbidity frequently including Fontan-associated liver disease (FALD). Markers of early FALD are lacking. We sought to measure hepatic venous oxygen saturation (ShVO2) obtained during surveillance cardiac catheterization of Fontan patients, as a potential early marker of early FALD. Fontan patients with ShVO2 measurements during catheterization between 2018 and 2023 at two institutions were included. In addition to catheterization data, exercise stress test, liver biopsy, liver elastography, and laboratory data were collected. 58 patients were included in the study. Catheterization with ShVO2 measurement occurred on average 13.6 years (range 7.3 − 25.1 years) after Fontan completion. The median ShVO2 was 59% (range 13–88%) and was on average 13% lower than the SVC saturation (ranging from 14% higher to 44% lower). ShVO2 was positively associated with SVC saturation (r = 0.267, p = 0.046) and time since Fontan completion (r = 0.303, p = 0.021). ShVO2 was not associated with fibrosis grade, liver function test, liver elastography, VO2 max, cardiac index by catheterization, or Fontan pressure. In conclusion, ShVO2 is not associated with current markers of liver dysfunction. Longitudinal study is needed to determine if decreased ShVO2 precedes the development FALD.