Fontan-associated liver disease and total cavopulmonary anatomical flow effectors.

OBJECTIVE: We investigated a relationship between a composite index comprised of Fontan-circuit anatomical features and hepatic fibrosis scores from biopsy. METHODS: We identified living extracardiac Fontan patients, ≥7 years old and ≥5 but <20 years postoperative, that underwent cardiac catheterization and transvenous liver biopsy between March 2012 and September 2020. We divided patients into anatomical groups and applied a risk score to each patient. We compared average anatomical risk scores with average hepatic total fibrosis scores by group. RESULTS: We identified 111 patients that met inclusion criteria. After excluding four patients, we assigned 107 to one of 12 anatomical variant groups (n ≥ 3). For the 107, the average age at liver biopsy was 14 ± 6 years old. Of the 107, 105 (98%) were New York Heart Association Class 1. We found average anatomical risk scores by group correlated with average total fibrosis scores by group (R = 0.8; p = .005). An average Fontan duration to biopsy of 10 ± 1 years was similar for all 12 anatomical groups. We found no other clinical variables, laboratory, or hemodynamic values that trended with anatomical risk scores or hepatic total fibrosis scores. CONCLUSIONS: In a cohort of relatively young, stable extracardiac Fontan patients, average composite anatomical risk scores strongly correlated with average hepatic total fibrosis scores by anatomical group. These findings suggest that some anatomical variants in extracardiac Fontan patients are associated with higher Fontan-associated liver disease (FALD)-related hepatic total fibrosis scores than others, despite similar Fontan durations.

The Rate of Hepatic Fibrosis Progression in Patients Post-Fontan.

This investigation analyzed the rate of hepatic fibrosis progression in post-Fontan patients that underwent hepatic biopsy. The study cohort comprised post-Fontan patients that underwent cardiac catheterization and transvenous liver biopsy between March 2012 and September 2019. We identified 126 patients that met inclusion criteria. Of the 126, 27 (21%) had a lateral tunnel Fontan, and 99 (79%) had an extracardiac Fontan. For the 27 lateral tunnel Fontan patients, age at Fontan was 4 ± 2 years, and for the 99 extracardiac Fontan patients age at Fontan was 4 ± 2 years (p = 0.98). For the 27 lateral tunnel Fontan patients, the average total fibrosis score was 3.0 ± 1.5; and for the 99 extracardiac Fontan patients, the average total fibrosis was 2.7 ± 1.7 (p = 0.48). For the lateral tunnel Fontan patients, the average Fontan duration was 20 ± 6 years; and for the 99 extracardiac Fontan patients, the average Fontan duration was 11 ± 5 years (p < 0.001). For the 27 lateral tunnel Fontan patients, the average rate of fibrosis progression was 0.16 ± 0.10 total fibrosis score/year; and for the 99 extracardiac Fontan patients, the average rate of fibrosis progression was 0.30 ± 0.23 total fibrosis score/year (p < 0.001). In conclusion, our findings suggest that those with extracardiac Fontans have a faster rate of hepatic fibrosis progression than those with lateral tunnel Fontans. More extensive or multi-institutional studies will be needed to confirm these findings and define the clinical significance of discrepant rates of hepatic fibrosis in post-Fontan patients.

Fontan venovenous collaterals and hepatic fibrosis.

OBJECTIVE: We hypothesized that a relationship might exist between angiographically demonstrable, post-Fontan venovenous collaterals, and hepatic fibrosis. METHODS: We analyzed data from post-Fontan patients that underwent cardiac catheterization and transvenous-hepatic biopsy procedures between March 2012 and March 2020. From innominate vein angiography, we determined those that either had or lacked venovenous collaterals. Additionally, we examined data from post-Fontan patients that underwent hepatic ultrasound, shear-wave elastography between January 2017 and March 2020. RESULTS: We identified 164 patients that met inclusion criteria. Of the 164, 101 (62%) had venovenous collaterals. Of the 101 with collaterals, average total fibrosis score (TFS) was 3.2 and the average rate of fibrosis progression was 0.28 vs an average TFS of 2.1 and an average fibrosis progression rate of 0.22 for those without collaterals (P = .00001 and P = .01, respectively). Of the 101 with collaterals, oxygen saturation was 91% ± 4% vs 93% ± 3% (P = .048) without collaterals. Of the 164, 86 (52%) underwent ultrasound shear-wave elastography. Of the 86 patients undergoing elastography, 50 (58%) were performed in those with collaterals, and 36 (42%) in those without collaterals. For the 50 with collaterals, average elastography values were 13.3 vs 11.2 kPa for the 36 without collaterals (P = .006). We found no statistically significant differences for age at biopsy, Fontan duration, Fontan-type, type of functional univentricle, laboratory, clinical, or hemodynamic values between those with or without collaterals. CONCLUSIONS: The presence of angiographically demonstrated venovenous collaterals was associated with statistically, significantly more advanced liver fibrosis than those without collaterals.

MELD-XI Scores Correlate with Post-Fontan Hepatic Biopsy Fibrosis Scores.

We tested the hypothesis that MELD-XI values correlated with hepatic total fibrosis scores obtained in 70 predominately stable, post-Fontan patients that underwent elective cardiac catheterization. We found a statistically significant correlation between MELD-XI values and total fibrosis scores (p = 0.003). Thus, serial MELD-XI values may be an additional useful clinical parameter for follow-up care in post-Fontan patients.

An Observation from Liver Biopsies Two Decades Post-Fontan.

This brief report describes an observation from liver biopsy results in nonfailing Fontan patients, currently in their second postoperative decade. In three patients, with either atriopulmonary or atrioventricular connections and functional left ventricles, we found no portal fibrosis. In contrast, we found portal fibrosis in three clinically similar, nonfailing Fontan patients with lateral tunnel connections and functional left ventricles. We recognize the results may be secondary to chance; nevertheless, we speculate about possible relevancy.

Fontan Outcomes and Pulmonary Blood Flow at Birth.

We previously noted, in a small group of post-Fontan patients, a possible association between hepatic fibrosis scores and the status of pulmonary blood flow at birth. To further explore this observation, we examined data from all Fontan patients seen in our center from July 2010 to March 2015. We identified 200 patients for analysis. Of the 200 patients, 56 underwent transvenous-hepatic biopsy. Of the 200 patients, 13 (6.5%) had protein-losing enteropathy. We divided both the 56 biopsy patients and the entire cohort of 200 patients into 4 groups: (1) unobstructed pulmonary blood flow at birth with functional left ventricles, (2) unobstructed pulmonary blood flow at birth with functional right ventricles, (3) obstructed pulmonary blood flow at birth with functional left ventricles, and (4) obstructed pulmonary blood flow at birth with functional right ventricles. Analysis of the 56 liver-biopsy patient groups showed median hepatic total-fibrosis scores for the 4 groups of 2 (0-6), 2 (0-8), 3 (2-6), and 4 (1-8), respectively, with statistical significance between groups 4 and 1 (p = 0.031). For the entire cohort of 200 patients, we analyzed the incidence of protein-losing enteropathy for each of the four groups and found protein-losing enteropathy percent occurrences of 0, 2.9, 8.8, and 16.1, respectively, with statistical significance between groups 4 and 2 (p = 0.031) and between groups 4 and 1 (p = 0.025). A history of obstructed pulmonary blood flow at birth, coupled with a functional right ventricle, may predict a poorer long-term Fontan outcome.

Fontan hepatic fibrosis and pulmonary vascular development.

Fontan patients are at risk for hepatic fibrosis; however, risk factors are unclear. We performed a multivariate analysis in a small cohort of 14 patients (7-24 years old, mean 15) with Fontan circulation, undergoing cardiac catheterization and transvenous liver biopsies, all demonstrating fibrosis. We found by stepwise regression analysis that the history of pulmonary atresia was a predictor of higher total hepatic fibrosis scores than a history of unobstructed pulmonary blood flow (p = 0.002). Other variables including age, time from Fontan, hemodynamic measurements, and laboratory values were not predictive of total fibrosis scores at p values <0.05. Hepatic fibrosis scores between those born with pulmonary atresia versus unrestricted pulmonary blood flow may reflect differences in pulmonary circulatory physiology, resulting from differences in pulmonary vascular development.

Transvenous hepatic biopsy in stable Fontan patients undergoing cardiac catheterization.

Liver pathology complicates Fontan palliation. Previous reports established that both hepatic sinusoidal and portal fibrosis occur in patients after Fontan procedures. Past studies predominantly included symptomatic patient cohorts. Thus, the authors of this study aimed to characterize hepatic pathology via transvenous hepatic biopsies in 21 asymptomatic patients at the time of elective cardiac catheterization. Seven of these patients (33 %) were accompanied by an interventional procedure. Hepatic biopsies showed evidence of either sinusoidal or portal fibrosis or both in all but one patient. The findings showed a statistically significant (p = 0.005) moderately strong positive correlation between fibrosis scores and time since Fontan surgery. Additionally, no significant correlation was found between fibrosis scores and inferior vena cava pressure, pulmonary vascular resistance, platelet counts, or serum laboratory testing of hepatic function.

Fontan-Associated Anatomical Variants and Hepatic Fibrosis.

OBJECTIVE: We hypothesized that a relationship between post-Fontan hepatic fibrosis and anatomical variants might exist. METHODS: Attempting to limit confounding variables, we analyzed data from living, stable, post-extracardiac Fontan patients who underwent cardiac catheterization and transvenous hepatic biopsy procedures between March 2012 and June 2020. RESULTS: We identified 120 patients who met the inclusion criteria. Of the 120, 35 (29%) had pulmonary artery stents. For the 35 with pulmonary artery stents, the average total fibrosis score was 3.2 ± 1.9 and the fibrosis progression rate was 0.36 ± 0.33, and for those with no pulmonary artery stents, the total fibrosis score was 2.6 ± 1.8 and the fibrosis progression rate was 0.27 ± 0.33 (P = .13 and P = .11, respectively). Of the 120, 65 had functional univentricles of right ventricular type. Of these 65, 27 had pulmonary artery stents. For the 27 with pulmonary artery stents, the average total fibrosis score was 3.4 ± 1.8 and the average fibrosis progression rate was 0.39 ± 0.30, and for the 38 without pulmonary artery stents, the average fibrosis score was 2.3 ± 1.5 and the average fibrosis progression rate was 0.23 ± 0.21 (P = .01 for comparison of both values). CONCLUSIONS: This study's findings suggest that a post-extracardiac Fontan with a functional univentricle of right ventricular type plus a pulmonary artery stent may have more advanced liver pathology than those without a pulmonary artery stent at similar Fontan duration years and ages at liver biopsy.

A composite noninvasive index correlates with liver fibrosis scores in post-Fontan patients: Preliminary findings.

OBJECTIVE: We hypothesized that clinic-based, hepatic-ultrasound, elastography measurements, either alone or in combination with other noninvasive variables, might correlate with liver-biopsy fibrosis scores in patients post-Fontan. METHODS: Between March 2012 and February 2017, we identified patients post-Fontan that underwent elective cardiac catheterization and simultaneous transvenous hepatic biopsy. From this group, we selected patients that met inclusion criteria for liver-ultrasound, shear-wave elastography. Utilizing the results of elastography, laboratory testing, and time post-Fontan, we constructed a composite Fontan hepatic index as a sum of elastography measurements in kilopascals, model for end-stage liver disease excluding INR scores, and the square root of the number of years post-Fontan. Further, we analyzed correlations between Fontan hepatic index values and fibrosis scores from hepatic biopsy. RESULTS: We identified a total of 79 post-Fontan patients that underwent cardiac catheterization and liver biopsy. Of the 79 patients, 53 met inclusion criteria, and 32 consented to undergo hepatic-ultrasound elastography. Of the 32 that underwent elastography, data from 30 patients was used for analysis. We found no statistically significant differences in demographics, laboratory values, or cardiac catheterization data between the 30 included patients and the 21 that did not participate. Utilizing data from the 30 included patients, we found a strong, highly statistically significant correlation between the Fontan hepatic index values and total fibrosis scores (R = 0.8, P < .00001). However, the cohort size prevented reliable discriminating cut-off values for the range of total fibrosis scores. CONCLUSIONS: In a small cohort of patients post-Fontan, preliminary findings suggest that the composite Fontan hepatic index might be a clinically useful, noninvasive method of serially monitoring for hepatic fibrosis. Further studies, with large patient cohorts, are necessary to validate our findings and develop clinically useful discriminatory cutoff values.