# Differences in Prevalence and Severity of Liver Disease Between Lateral Tunnel and Extracardiac Conduit Fontan

## TL;DR

This study found that patients with extracardiac conduit Fontan connections had more severe and progressive liver disease compared to those with lateral tunnel connections.

## Contribution

The study is the first to compare liver disease outcomes between ECC and LT Fontan types in two distinct cohorts.

## Key findings

- ECC patients had higher cirrhosis prevalence and worse liver disease severity at baseline compared to LT patients.
- ECC patients showed greater progression of liver disease over time compared to LT patients.
- No significant differences were found in liver disease outcomes between ECC and LT patients in the FC-TCPC cohort.

## Abstract

Recent studies suggest differences in liver disease severity based on the type of total cavopulmonary connection (TCPC).

The purpose of this study was to compare the severity and progression of liver disease between patients with extracardiac conduit (ECC) vs lateral tunnel (LT) using 2 separate cohorts: i) TCPC at the initial Fontan operation (primary-TCPC cohort) and ii) Fontan conversion (FC) to TCPC (FC-TCPC cohort).

This is a retrospective study of adults with TCPC (ECC [N = 62, 46%]; LT [N = 73,54%). Liver disease severity was assessed at baseline using biomarkers (model for end-stage liver disease excluding international normalized ratio, Fibrosis-4 [FIB-4], aspartate aminotransferase to platelet ratio index [APRI]), and progression of liver disease was assessed as temporal change in biomarkers at 3, 5, and 7 years.

In the primary-TCPC cohort (ECC [N = 62,46%]; LT [N = 73,54%), patients with ECC had a higher prevalence of cirrhosis (27% vs 12%; P = 0.03) and worse disease severity at baseline (APRI 0.46 [0.34;0.61] vs 0.39 [0.29;0.52], P < 0.001; FIB-4 (0.89 [0.59;1.12] vs 0.76 [0.31;0.99], P = 0.009) compared to LT. Both groups had progression of liver disease (temporal increase in biomarker levels), but the ECC group had a greater temporal increase in biomarker levels resulting in a higher relative increase in model for end-stage liver disease excluding international normalized ratio, FIB-4, and APRI. There were no significant differences in prevalence and severity of liver disease at baseline, or liver disease progression during follow-up between patients with ECC vs LT in the FC-TCPC group.

ECC was associated with a higher prevalence and worse severity of liver disease at baseline, and greater disease progression during follow-up compared to those with LT. Further studies are required to determine the optimal strategies for the management of liver disease in patients with ECC.