A window into portal hemodynamics in adult fontan patients?

Fontan circulation alters portal venous hemodynamics, causing chronic passive hepatic congestion and fibrosis. This congestion increases liver stiffness (LS) leading to overestimates of liver fibrosis as measured by ultrasound shear wave elastography (SWE) of the liver. We evaluated whether Fontan circulation has a similar effect on spleen stiffness (SS) and SS/LS ratio as measured by SWE.

We retrospectively compared the SS of adult Fontan patients to age and gender matched, control patients without congenital heart disease. We correlated SS measurements to LS measurements and also performed a limited subgroup analysis of SS in Fontan patients with various manifestations of Fontan Associated Liver Disease.

SS in Fontan patients was similar to healthy controls (1.43 vs. 1.36 m/s, p = 0.26). LS was elevated in 78% of the Fontan patients (mean 1.68 m/s, SD 0.31, 95% CI 1.53-1.85). The correlation between LS and SS was modest (Pearson's correlation coefficient, r = 0.5) but did not reach statistical significance (p = 0.06). The mean SS/LS ratio was 0.85 (95% CI 0.77-0.94).

Based on our study cohort, SS in Fontan patients is similar to age and gender matched control patients without congenital heart disease. The SS/LS ratio, however, is frequently less than 1, which is lower than that reported in both healthy patients and those with other forms of non-cardiac liver disease. SS and SS/LS ratio may be a useful indicator of portal hemodynamics in Fontan patients.