Hepatic and renal end-organ damage in the Fontan circulation: A report from the Australian and New Zealand Fontan Registry.

Background: Hepatic and renal dysfunction have been observed in survivors of the Fontan procedure, however their incidence and associated factors remain poorly defined.
Methods: A total of 152 participants from a Registry of 1528 patients underwent abdominal ultrasound, transient elastography (FibroScan), serum fibrosis score (FibroTest), in vivo Tc-99m DTPA measurement of glomerular filtration rate (mGFR), and urine albumin-creatinine ratio (ACR).
Results: Mean age and time since Fontan were 19.8 ± 9.3 and 14.1 ± 7.6 years, respectively. Features suggestive of hepatic fibrosis were observed on ultrasound in 87/143 (61%) and no patient was diagnosed with hepatocellular carcinoma. FibroScan median kPa was ≥10 in 117/133 (88%), ≥15 in 75/133 (56%), and ≥20 in 41/133 (31%). Fifty-four patients (54/118, 46%) had a FibroTest score ≥0.49 (equivalent to ≥F2 fibrosis). FibroTest score correlated with FibroScan value (r = 0.24, p = 0.015) and ACR (r = 0.29, p = 0.002), and patients with ultrasound features of hepatic fibrosis had a higher FibroScan median kPa (19.5 vs 15.4, p = 0.002). Renal impairment was mild (mGFR 60-89 ml/min/1.73 m ² ) in 46/131 (35%) and moderate (mGFR 30-59 ml/min/1.73 m ² ) in 3/131 (2%). Microalbuminuria was detected in 52/139 participants (37%). By multivariable analysis, time since Fontan was associated with increased FibroScan median kPa (β = 0.89, 95% CI 0.54-1.25, p = 0.002) and decreased mGFR (β = -0.77, 95% CI -1.29-0.24, p = 0.005).
Conclusions: In the second decade after Fontan hepatic and renal structure and function are abnormal in a significant number of patients: close to 60% have ultrasonographic evidence of structural hepatic abnormalities, 46% have elevated serum hepatic fibrosis scores, and 57% have either reduced glomerular filtration rate or microalbuminuria. Hepatic and renal function should be monitored for potential impacts on outcomes after Fontan completion.
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