Noninvasive Assessment of Liver Fibrosis in Adult Patients Following the Fontan Procedure

Fontan-Associated Liver Disease: A Review

Fontan-associated liver disease (FALD) is a chronic complication of the Fontan procedure, a palliative surgery for patients with congenital heart disease that results in a single-ventricle circulation. The success of the Fontan procedure has led to a growing population of post-Fontan patients living well into adulthood. For this population, FALD is a major cause of morbidity and mortality. It encompasses a spectrum of hepatic abnormalities, ranging from mild fibrosis to cirrhosis and hepatocellular carcinoma. The pathophysiology of FALD is multifactorial, involving hemodynamic and inflammatory factors. The diagnosis and monitoring of FALD present many challenges. Conventional noninvasive tests that use liver stiffness as a surrogate marker of fibrosis are unreliable in FALD, where liver stiffness is also a result of congestion due to the Fontan circulation. Even invasive tissue sampling is inconsistent due to the patchy distribution of fibrosis. FALD is also associated with both benign and malignant liver lesions, which may exhibit similar imaging features. There is therefore a need for validated diagnostic and surveillance protocols to address these challenges. The definitive treatment of end-stage FALD is also a subject of controversy. Both isolated heart transplantation and combined heart-liver transplantation have been employed, with the latter becoming increasingly preferred in the US. This article reviews the current literature on the epidemiology, pathophysiology, diagnosis, and management of FALD, and highlights knowledge gaps that require further research.

Clinical Outcomes of Adult Fontan-Associated Liver Disease and Combined Heart-Liver Transplantation

BACKGROUND

The impact of Fontan-associated liver disease (FALD) on post-transplant mortality and indications for combined heart-liver transplant (CHLT) in adult Fontan patients remains unknown.

OBJECTIVES

The purpose of this study was to assess the impact of FALD on post-transplant outcomes and compare HT vs CHLT in adult Fontan patients.

METHODS

We performed a retrospective-cohort study of adult Fontan patients who underwent HT or CHLT across 15 centers. Inclusion criteria were as follows: 1) Fontan; 2) HT/CHLT referral; and 3) age ≥16 years at referral. Pretransplant FALD score was calculated using the following: 1) cirrhosis; 2) varices; 3) splenomegaly; or 4) ≥2 paracenteses.

RESULTS

A total of 131 patients (91 HT and 40 CHLT) were included. CHLT recipients were more likely to be older (P = 0.016), have a lower hemoglobin (P = 0.025), require ≥2 diuretic agents pretransplant (P = 0.051), or be transplanted in more recent decades (P = 0.001). Postmatching, CHLT demonstrated a trend toward improved survival at 1 year (93% vs 74%; P = 0.097) and improved survival at 5 years (86% vs 52%; P = 0.041) compared with HT alone. In patients with a FALD score ≥2, CHLT was associated with improved survival (1 year: 85% vs 62%; P = 0.044; 5 years: 77% vs 42%; P = 0.019). In a model with transplant decade and FALD score, CHLT was associated with improved survival (HR: 0.33; P = 0.044) and increasing FALD score was associated with worse survival (FALD score: 2 [HR: 14.6; P = 0.015], 3 [HR: 22.2; P = 0.007], and 4 [HR: 27.8; P = 0.011]).

CONCLUSIONS

Higher FALD scores were associated with post-transplant mortality. Although prospective confirmation of our findings is necessary, compared with HT alone, CHLT recipients were older with higher FALD scores, but had similar survival overall and superior survival in patients with a FALD score ≥2.

Liver parenchymal changes and association with cardiac magnetic resonance imaging findings in repaired tetralogy of Fallot: an intravoxel incoherent motion magnetic resonance imaging study

BACKGROUND

Liver disease can develop in repaired tetralogy of Fallot (TOF) from hepatic congestion caused by volume and pressure overload of the right ventricle. Noninvasive assessment of the liver is important for diagnosing and managing children with TOF.

OBJECTIVE

To evaluate subclinical hepatic changes without liver function test abnormality in adolescents with repaired TOF using intravoxel incoherent motion (IVIM) MRI and cardiac MRI findings.

MATERIALS AND METHODS

We included 106 young adults (75 with repaired TOF and 31 healthy individuals) in the study. Liver IVIM MRI examinations were performed with 10 b values (0, 10, 20, 30, 50, 80, 100, 200, 400, 800 s/mm²). Two observers measured IVIM MRI parameters D true, D* and f, as well as apparent diffusion coefficient (ADC) values in liver segments 5-8.

RESULTS

D* and f values were significantly lower in adolescents with TOF (P = 0.003 vs. P = 0.05, respectively). ADC values were higher in adolescents with TOF (P = 0.005). However, we found no significant difference between adolescents with and without TOF in terms of Dtrue (P = 0.53). There was a significant correlation between f value and right ventricular ejection fraction. The intraclass correlation coefficient (ICC) analysis of the two observers showed substantial-to-excellent agreement for D, f, D true and ADC (0.7, 0.8, 0.9 and 0.8, respectively).

CONCLUSION

The results of our study suggest that impaired microperfusion with increased ADC values in adolescents with repaired TOF reflect hepatic congestion rather than fibrosis. Hepatic congestion characterized by decreased ADC values can be easily differentiated before fibrotic changes occur by using IVIM MRI to assess diffusion and microcapillary perfusion separately.

Non-invasive assessment of liver abnormalities in pediatric Fontan patients

Liver abnormalities are well known among long-term survivors of Fontan palliation, which remains the definite surgery for complex congenital heart disease and single ventricle physiology. Pediatric data however are scarce. We assessed the prevalence and degree of liver abnormalities in pediatric Fontan patients through non-invasive investigations suitable for longitudinal follow-up. Thirty-five patients with a median age of 11.8 years (5.2-16.6) and median time since Fontan of 6 years (1.17-13.83) were studied. Each child underwent a blood test, liver Doppler ultrasound (US), and transient elastography (TE). Healthy children were used as controls for TE measurement. AST, ALT, γGT, and direct bilirubin were abnormal in respectively 12 (34%), 5 (14%), 24 (69%), and 7 (20%) patients, while platelet count was decreased in 7 (20%). Splenomegaly was present in 7 (20%) patients. Portal vein mean flow velocity was < 15 cm/s in 19 (54%) patients indicative of portal hypertension. Twenty-two patients (63%) showed inferior vena cava collapsibility index values below 17%, indicating venous congestion. Hepatic artery and superior mesenteric artery resistance index were inversely correlated with time post Fontan (p < 0.05). TE values in Fontan patients were significantly higher than controls, with a median of 12.6 versus 4.6 kPa (p < 0.001) and were already increased shortly after Fontan completion. Conclusion: Liver abnormalities are frequently observed in pediatric Fontan patients. The non-invasive investigations used were not able to confirm liver fibrosis or differentiate hepatic congestion from fibrosis. Based on our findings, we propose a prospective screening protocol with serial measurements of laboratory, (Doppler) US, and TE parameters. What is Known: • Hepatic dysfunction is a well-known consequence of the Fontan circulation. • The natural history of Fontan-associated liver disease in the pediatric age group remains unclear. What is New: • Liver abnormalities are frequently observed in pediatric Fontan patients; however, differentiating liver fibrosis and hepatic congestion with non-invasive investigations remains challenging. Sonographic Doppler measurements may improve our insight in both Fontan-associated liver disease development and the functioning of the Fontan circulation. • A prospective screening protocol is proposed to improve our ability to detect Fontan-associated liver disease early on and understand its natural history.

Fontan-associated liver disease: pathophysiology, investigations, predictors of severity and management

Cardiac hepatopathy is the liver injury resulting from congestion and ischaemia associated with acute or chronic heart failure. The improved longevity of adults with operated congenital heart disease who develop heart failure as an increasingly late event makes this form of liver injury increasingly clinically relevant. Patients with congenital heart disease with a single ventricle anomaly, who require creation of a Fontan circulation, are particularly vulnerable as they have elevated venous filling pressures with chronic liver congestion. Progression to liver fibrosis and eventually cirrhosis may occur, with its associated risks of liver failure and hepatocellular carcinoma. This risk likely increases over the patient's lifetime, related to the duration post-surgical repair and reflects the chronicity of congestion. Liver biopsy is rarely performed due to a higher risk of complications in the setting of elevated venous pressures, and the frequent use of anticoagulation. Non-invasive methods of liver assessment are poorly validated and different factors require consideration compared to other chronic liver diseases. This review discusses the current understanding of cardiac hepatopathy in congenital heart disease patients with a Fontan circulation. This entity has recently been called Fontan Associated Liver Disease in the literature, with the term useful in recognising that the pathophysiology is incompletely understood, and that long-standing venous pressure elevation and hypoxaemia are presumed to play an additional significant role in the pathogenesis of the liver injury.

Intravoxel incoherent motion imaging has the possibility to detect liver abnormalities in young Fontan patients with good hemodynamics

INTRODUCTION

Liver fibrosis and cirrhosis are one of the critical complications in Fontan patients. However, there are no well-established non-invasive and quantitative techniques for evaluating liver abnormalities in Fontan patients. Intravoxel incoherent motion diffusion-weighted imaging with MRI is a non-invasive and quantitative method to evaluate capillary network perfusion and molecular diffusion. The objective of this study is to assess the feasibility of intravoxel incoherent motion imaging in evaluating liver abnormalities in Fontan children.

MATERIALS AND METHODS

Five consecutive Fontan patients and four age-matched healthy volunteers were included. Fontan patients were 12.8 ± 1.5 years old at the time of MRI scan. Intravoxel incoherent motion imaging parameters (D, D*, and f values) within the right hepatic lobe were compared. Laboratory test, ultrasonography, and cardiac MRI were also conducted in the Fontan patients. Results of cardiac catheterization conducted within one year of the intravoxel incoherent motion imaging were also examined.

RESULTS

In Fontan patients, laboratory test and liver ultrasonography showed almost normal liver condition. Cardiac catheter and MRI showed good Fontan circulation. Cardiac index was 2.61 ± 0.23 L/min/m2. Intravoxel incoherent motion imaging parameters D, D*, and f values were lower in Fontan patients compared with controls (D: 1.1 ± 0.0 versus 1.3 ± 0.2 × 10-3 mm2/second (p = 0.04), D*: 30.8 ± 24.8 versus 113.2 ± 25.6 × 10-3 mm2/second (p < 0.01), and f: 13.2 ± 3.1 versus 22.4 ± 2.4% (p < 0.01), respectively).

CONCLUSIONS

Intravoxel incoherent motion imaging is feasible for evaluating liver abnormalities in children with Fontan circulation.

Liver disease secondary to congenital heart disease in children

Introduction: Hepatic fibrosis and hepatocellular carcinoma (HCC) can develop in children with congenital heart disease. Although hepatic fibrosis and HCC are prone to develop after the Fontan operation, they can also develop in patients suffering from congenital heart disease who have not undergone Fontan operation. Area covered: The history of cardiac hepatopathy including Fontan-associated liver disease is described. Patient characteristics, liver histology, imaging examinations and blood tests are reviewed to elucidate the mechanism of cardiac hepatopathy. In addition, a flowchart for the follow-up management of cardiac hepatopathy in children with congenital heart disease is proposed. Expert opinion: Congestion and low cardiac output are the main causes of cardiac hepatopathy. Advanced hepatic fibrosis is presumed to be associated with HCC. HCC can develop in both adolescents and young adults. Regardless of whether the Fontan operation is performed, children with a functional single ventricle and chronic heart failure should be regularly examined for cardiac hepatopathy. There is no single reliable laboratory parameter to accurately detect cardiac hepatopathy; hepatic fibrosis indices and elastography have shown inconsistent results for detection of this disease. Further studies using liver specimen-confirmed patients and standardization of evaluation protocols are required to clarify the pathogenesis of cardiac hepatopathy.

Long Term Consequences of the Fontan Procedure and How to Manage Them

In 1971, Fontan and Baudet described a surgical technique for successful palliation of patients with tricuspid atresia. Subsequently, this technique has been applied to treat most forms of functional single ventricles and has become the current standard of care for long-term palliation of all patients with single ventricle congenital heart disease. Since 1971, the Fontan procedure has undergone several variations. These patients require lifelong management including a thorough knowledge of their anatomic substrate, hemodynamic status, management of rhythm and ventricular function along with multi organ evaluation. As these patients enter middle age, there is increasing awareness regarding the long-term complications and mortality. This review highlights the long-term outcomes of the Fontan procedure and management of late sequelae.

FibroSURE and elastography poorly predict the severity of liver fibrosis in Fontan-associated liver disease

OBJECTIVE

As the population of patients with Fontan circulation surviving into adulthood increases, hepatic cirrhosis has grown to be a significant cause of morbidity and mortality. Early detection of advanced hepatic fibrosis is imperative for proper intervention and consideration for heart or combined heart/liver transplantation. Noninvasive biomarkers and elastography have been evaluated for their diagnostic utility with variable results in the Fontan population.

DESIGN

The cohort included 14 patients age 26.4 SD 7.5 who underwent Fontan surgery. All patients were evaluated with FibroSURE, shear wave elastography (SWE), hepatic duplex sonography, and liver biopsy. Liver fibrosis on biopsy was evaluated according to the congestive hepatic fibrosis system.

RESULTS

In our cohort, 100% of patients had fibrosis with 36% demonstrating advanced fibrosis. FibroSURE agreed with liver biopsy in only 5 out of 14 cases (36%): underestimating in 7 and overestimating in 2 individuals. SWE agreed with liver biopsy in 0% of cases: overestimating in 10 and underestimating in 4 cases. None of the duplex sonography indices predicted the presence or severity of liver fibrosis.

CONCLUSION

This study demonstrates that children who have undergone a Fontan procedure universally develop some hepatic fibrosis and a significant number have advanced fibrosis by adulthood. The FibroSURE blood test, SWE, and hepatic duplex sonography were unable to accurately predict the presence or severity of hepatic fibrosis when compared with liver biopsy. Further studies are needed to investigate novel noninvasive methods and/or biomarkers that can adequately detect advanced hepatic fibrosis before the development of cirrhosis and hepatic decompensation.

Cardiopulmonary exercise testing in the evaluation of liver disease in adults who have had the Fontan operation

BACKGROUND

Liver disease (LD) is a long-term complication in patients with a single ventricle who have had the Fontan operation. A decline in cardiopulmonary exercise testing (CPET) variables is associated with increased risk of hospitalization, but its association with LD is unknown.

AIM

To determine the association between CPET variables and LD in adults who have had the Fontan operation.

METHODS

We retrospectively reviewed the medical records from two tertiary institutions.

RESULTS

We identified 114 adults (≥18 years; mean 30.9±7.4 years) who had undergone the Fontan operation: 56% were women; 63% had total cavopulmonary connection; 66% had New York Heart Association (NYHA) class I status; 42% had arrhythmias; 22% had systemic right ventricle; and 35% had ventricular dysfunction. Of 81 patients with liver-imaging data, 41% had LD (i.e. imaging evidence of cirrhosis, with or without portal hypertension, splenomegaly or varices). There were no differences in clinical or echocardiographic variables between those with and without LD. Among the 58 patients with CPET data, mean peak oxygen consumption (VO₂) was 18.6±5.7mL/kg/min, per-cent-predicted peak VO₂ was 53.9±15.5%, peak oxygen pulse was 9.3±2.9mL/beat and per-cent-predicted peak oxygen pulse was 82.6±21.5%. Of the 44 patients with liver and CPET data, each standard deviation decrease in per-cent-predicted peak VO₂ (16%) and per-cent-predicted peak oxygen pulse (22%) was associated with a 2.3-fold increase in the odds of LD, after adjusting for NYHA, institution and Fontan type (P=0.04). Similarly, each standard deviation decrease in per-cent-predicted peak VO₂ and oxygen pulse was associated with an estimated 5.9-year and 4.9-year earlier onset of LD, respectively (P>0.05).

CONCLUSIONS

Decline in per-cent-predicted peak VO₂ and oxygen pulse was associated with increased odds of LD in adults who had undergone the Fontan operation. Our study supports more rapid hepatic evaluation among patients with abnormal or worsening CPET variables.

Diagnosis and Management of Noncardiac Complications in Adults With Congenital Heart Disease: A Scientific Statement From the American Heart Association

Life expectancy and quality of life for those born with congenital heart disease (CHD) have greatly improved over the past 3 decades. While representing a great advance for these patients, who have been able to move from childhood to successful adult lives in increasing numbers, this development has resulted in an epidemiological shift and a generation of patients who are at risk of developing chronic multisystem disease in adulthood. Noncardiac complications significantly contribute to the morbidity and mortality of adults with CHD. Reduced survival has been documented in patients with CHD with renal dysfunction, restrictive lung disease, anemia, and cirrhosis. Furthermore, as this population ages, atherosclerotic cardiovascular disease and its risk factors are becoming increasingly prevalent. Disorders of psychosocial and cognitive development are key factors affecting the quality of life of these individuals. It is incumbent on physicians who care for patients with CHD to be mindful of the effects that disease of organs other than the heart may have on the well-being of adults with CHD. Further research is needed to understand how these noncardiac complications may affect the long-term outcome in these patients and what modifiable factors can be targeted for preventive intervention.

Noninvasive Liver Assessment in Adult Patients With Fontan Circulation Using Acoustic Radiation Force Impulse Elastography and Hepatic Magnetic Resonance Imaging

BACKGROUND

Patients who have undergone the Fontan procedure are at risk of developing hepatic dysfunction. However, broad recommendations regarding liver monitoring are limited. The purpose of this study was to characterize the frequency of liver disease in adult Fontan patients using multimodality imaging (hepatic magnetic resonance imaging [MRI], acoustic radiation force impulse [ARFI] elastography, or hepatic ultrasound).

METHODS

In a prospective cross-sectional analysis of adult patients palliated with a Fontan procedure, hepatic MRI, ARFI, and hepatic ultrasound were used to assess for liver disease. The protocol compared (1) varying prevalence of liver disease based on each imaging technique, (2) agreement between different techniques, and (3) association between noninvasive imaging diagnosis of liver disease and clinical variables, including specific liver disease biomarkers.

RESULTS

Thirty-seven patients were enrolled. The ARFI results showed high wave propagation velocity in 35 patients (94.6%). All patients had some abnormality in the hepatic MRI. Specifically, 8 patients (21.6%) showed signs of chronic liver disease, 10 patients (27%) had significant liver fibrosis, and 27 patients (73%) had congestion. No correlation was found between liver stiffness measured as propagation velocity and hepatic MRI findings. Only 7 patients had an abnormal hepatic ultrasound study.

CONCLUSIONS

There is an inherent liver injury in adult Fontan patients. Signs of liver disease were observed in most patients by both hepatic MRI and ARFI elastography but not by ultrasound imaging. Increased liver stiffness did not identify specific disease patterns from MRI, supporting the need for multimodality imaging to characterize liver disease in Fontan patients.

The Miracle Baby Grows Up: Hypoplastic Left Heart Syndrome in the Adult

PURPOSE OF REVIEW

Hypoplastic left heart syndrome (HLHS) is characterized by underdevelopment of the mitral valve, left ventricle, and aorta and is ultimately palliated with a single-ventricle repair. Universally fatal in infancy prior to the advent of modern surgical techniques, the majority of HLHS patients will now reach adulthood. However, despite improvements in early survival, the HLHS population continues to face significant morbidity and early mortality. This review delineates common sources of patient morbidity and highlights areas in need of additional research for this growing segment of the adult congenital heart disease population.

RECENT FINDINGS

It has become increasingly clear that palliated adult single ventricle patients, like those with HLHS, face significant life-long morbidity from elevated systemic venous pressures as a consequence of the Fontan procedure. Downstream organ dysfunction secondary to elevated Fontan pressures has the potential to significantly impact long-term management decisions, including strategies of organ allocation. Because of the presence of a morphologic systemic right ventricle, HLHS patients may be at even higher risk than other adult patients with a Fontan. Because the adult HLHS population continues to grow, recognition of common sources of patient morbidity and mortality is becoming increasingly important. A coordinated effort between patients and providers is necessary to address the many remaining areas of clinical uncertainty to help ensure continued improvement in patient prognosis and quality of life.

Living with Tricuspid Atresia: Case Report with Review of Literature

Tricuspid atresia (TA) is a rare congenital heart defect in which the right atrioventricular connection, the tricuspid valve, is absent. As a result, there is no direct communication between the right atrium and right ventricle. Surgical treatment, including the Fontan procedure, is indicated yet palliative, leaving patients with various lifelong complications. A comprehensive literature review revealed a paucity of evidence-based education on the identification, evaluation, management, treatment, and life span implications of TA. We present a case of TA from birth through adulthood, while simultaneously assessing the literature, to report the most current evidence relative to living with TA after surgical palliation. In addition, the embryology, methods of prenatal and postnatal diagnosis, potential complications, management, anticipatory guidance, and educational needs of both parents and patient are discussed.

Non-invasive Investigations for the Diagnosis of Fontan-Associated Liver Disease in Pediatric and Adult Fontan Patients

Fontan-associated liver disease (FALD) is a serious complication related to the chronically elevated venous pressure and low cardiac output of this abnormal circulation. However, diagnostic markers for this condition are limited. We hypothesized that specific tests for fibrosis developed for other chronic liver diseases would identify a higher prevalence of FALD than ultrasound and standard laboratory tests and that identified abnormalities would correlate with time post-Fontan. In this cross-sectional study, we assessed 19 children (average age 8.4 ± 4.3 and 5.4 ± 4.1 years post-Fontan) and 8 adults (average age 31.5 ± 8.9 and 21.1 ± 4 years post-Fontan) using standard serum laboratory investigations assessing hepatic integrity and function, the FibroTest, liver ultrasound, and transient elastography (FibroScan). In adult Fontan patients, hemoglobin, C-reactive protein, and gamma-glutamyl transpeptidase were significantly increased, and white blood cell and platelet counts were significantly decreased in comparison to the pediatric cohort. International normalized ratio was mildly elevated in both children and adults. FibroTest results were suggestive of fibrosis regardless of time post-Fontan. FibroScan measurements were significantly correlated with time post-Fontan, but the incidence of ultrasound-detected liver abnormalities was variable. No cases of hepatocellular carcinoma were identified. Abnormalities suggestive of FALD occur in both children and adults post-Fontan. Select laboratory tests, and possibly ultrasound and FibroScan in some patients, appear to have the most promise for the non-invasive detection of FALD.

NET Blood Transcript Analysis Defines the Crossing of the Clinical Rubicon: When Stable Disease Becomes Progressive

BACKGROUND/AIMS

A key issue in gastroenteropancreatic neuroendocrine tumors (GEP-NETs) is early identification and prediction of disease progression. Clinical evaluation and imaging are limited due to the lack of sensitivity and disease indolence. We assessed the NETest as a predictive and prognostic marker of progression in a long-term follow-up study.

METHODS

GEP-NETs (n = 34) followed for a median 4 years (2.2-5.4) were evaluated. WHO tumor grade/stage grade 1: n = 17, grade 2: n = 14, grade 3: n = 1 (for 2, no grade was available); 31 (91%) were stage IV. Baseline and longitudinal imaging and blood biomarkers were available in all, and progression was defined per standard clinical protocols (RECIST 1.0). The NETest was measured by quantitative PCR of blood and multianalyte algorithmic analysis (disease activity scaled 0-100% with low <40% and high activity risk cutoffs >80%); chromogranin A (CgA) was measured by radioimmunoassay (normal <150 µg/l); progression-free survival (PFS) was analyzed by Cox proportional-hazard regression and Kaplan-Meier analysis.

RESULTS

At baseline, 100% were NETest positive, and CgA was elevated in 50%. The only baseline variable (Cox modeling) associated with PFS was NETest (hazard ratio = 1.022, 95% confidence interval = 1.005-1.04; p < 0.012). Using Kaplan-Meier analyses, the baseline NETest (>80%) was significantly associated (p = 0.01) with disease progression (median PFS 0.68 vs. 2.78 years with <40% levels). The NETest was more informative (96%) than CgA changes (<under>></under>25%) in consistently predicting disease alterations (40%, p < 2 × 10-5, χ2 = 18). The NETest had an earlier time point change than imaging (1.02 ± 0.15 years). Baseline NETest levels >40% in stable disease were 100% prognostic of disease progression versus CgA (χ2 = 5, p < 0.03). Baseline NETest values <40% accurately (100%) predicted stability over 5 years (p = 0.05, χ2 = 3.8 vs. CgA).

CONCLUSION

The NETest correlated with a well-differentiated GEP-NET clinical status. The NETest has predictive and prognostic utility for GEP-NETs identifying clinically actionable alterations ∼1 year before image-based evidence of progression.

The Long-Term Management of Children and Adults with a Fontan Circulation: A Systematic Review and Survey of Current Practice in Australia and New Zealand

Although long-term survival is now the norm, Fontan patients face significant morbidity and premature mortality. Wide variation exists in long-term Fontan management. With an aim of improving their long-term management, we conducted a systematic review to identify best available evidence and gaps in knowledge for future research focus. We also surveyed cardiologists in Australia and New Zealand managing Fontan patients, to determine the alignment of current local practice with best available evidence. A systematic review was conducted using strict search criteria (PRISMA guidelines), pertaining to long-term Fontan management. All adult congenital and paediatric cardiologists registered with The Australia and New Zealand Fontan Registry were invited to respond to an online survey. Reasonable quality evidence exists for non-inferiority of aspirin over warfarin for thromboprophylaxis in standard-risk Fontan patients. No strong evidence is currently available for the routine use of ACE inhibitors, beta blockers or pulmonary vasodilators. Little evidence exists regarding optimal arrhythmia treatment, exercise restriction/prescription, routine fenestration closure, elective Fontan conversion and screening/management of liver abnormalities. Although pregnancy is generally well tolerated, there are high rates of miscarriage and premature delivery. Thirty-nine out of 78 (50 %) cardiologists responded to the survey. Heterogeneity in response was demonstrated with regard to long-term anti-coagulation, other medication use, fenestration closure and pregnancy and contraception counselling. Substantial gaps in our knowledge remain with regard to the long-term management of Fontan patients. This is reflected in the survey of cardiologists managing these patients. We have identified a number of key areas for future research.

Liver health in adults with Fontan circulation: A multicenter cross-sectional study

OBJECTIVES

Liver disease is an important contributor to morbidity and mortality in patients after Fontan surgery. There has been no large-scale survey of liver health in this population. We sought to explore the prevalence and predictors of liver disease in a multicenter cohort of adults with Fontan physiology.

METHODS

Subjects were recruited from 6 adult congenital heart centers. Demographics; clinical history; and laboratory, imaging, and histopathology data were obtained.

RESULTS

Of 241 subjects (median age 25.8 years [11.8-59.4], median time since Fontan 20.3 years [5.4-34.5]), more than 94% of those who underwent testing (208 of 221) had at least 1 abnormal liver-related finding. All hepatic imaging (n = 54) and liver histology (n = 68) was abnormal. Subjects with abnormal laboratory values had higher sinusoidal fibrosis stage (2 vs 1, P = .007) and higher portal fibrosis stage (3 vs 1, P = .003) compared with those with all normal values. Low albumin correlated with lower sinusoidal fibrosis stage (1 vs 2; P = .02) and portal fibrosis stage (0 vs 3, P = .002); no other liver studies correlated with fibrosis. Regenerative nodules were seen on 33% of histology specimens.

CONCLUSIONS

Regardless of modality, findings of liver disease are common among adults with Fontan circulation, even those appearing clinically well. Cirrhosis is present in up to one-third of subjects. Correlations between hepatic fibrosis stage and clinical history or findings on noninvasive testing are few. Further research is needed to identify patients at risk for more severe liver disease and to determine the best methods for assessing liver health in this population.

Effect of Fontan operation on liver stiffness in children with single ventricle physiology

OBJECTIVES

Assess liver stiffness using ultrasound point shear wave elastography (US P-SWE) in children before and after the Fontan operation.

METHODS

Eighteen children undergoing the Fontan operation were prospectively enrolled. Eight US P-SWE measurements were obtained from the right hepatic lobe before surgery, and at multiple postoperative time points. Temporally related inferior vena cava pressure (IVC) data was collected from medical records, when available. Changes in mean liver shear wave speed (SWS) were assessed using a mixed-effect model with post hoc Tukey correction. Changes in IVC pressure were evaluated using the Wilcoxon signed-rank test. A p value less than 0.05 was considered significant.

RESULTS

Mean age at enrolment was 33.5 ± 10.5 months. Baseline mean liver SWS was normal at 1.18 ± 0.29 m/s, increased to 2.28 ± 0.31 m/s at 2.5 ± 1.2 days (p < 0.0001) and to 2.22 ± 0.38 m/s at 7.5 ± 1.4 days (p < 0.0001). Five subjects returned at a mean of 185 ± 28 days, and mean liver SWS remained elevated at 2.08 ± 0.24 m/s (p < 0.0001). Mean IVC pressure increased from 7.2 ± 2.6 mmHg at baseline to 16.44 ± 3.3 mmHg at 2.2 ± 0.8 days post-surgery (p = 0.004).

CONCLUSION

The Fontan operation immediately and chronically increases liver stiffness and IVC pressure. Our study provides further evidence that congestion is a key driver of Fontan-associated liver disease.

KEY POINTS

• The Fontan operation triggers immediate hepatic congestion and marked liver stiffening. • Congestion, not fibrosis, drives early increased liver stiffness in Fontan patients. • Hepatic congestion persists chronically for months after the Fontan operation. • Congestion confounds shear wave elastography as a post-Fontan liver fibrosis biomarker.

Predictive value of biomarkers of hepatic fibrosis in adult Fontan patients

BACKGROUND

Hepatic fibrosis is highly prevalent in individuals with Fontan circulation. FibroSure (LabCorp, Burlington, NC) and hyaluronic acid (HA) have been validated for assessment of hepatic fibrosis in several forms of liver disease. We sought to determine whether these tests could identify Fontan patients with advanced hepatic fibrosis or cirrhosis.

METHODS

Subjects who had liver biopsy and FibroSure or HA testing within 6 months of biopsy were identified from the Alliance for Adult Research in Congenital Cardiology Fontan Liver Health study. Biopsy specimens were scored for degree of sinusoidal and portal fibrosis on a 3- and 5-point scale, respectively. Histologic findings were correlated with FibroSure and HA results.

RESULTS

The study included 27 subjects. Median age was 26.8 years (range, 17.4-59.8 years), and the median time since the Fontan surgery was 20.4 years (range, 12.0-31.3 years). FibroSure scores were elevated (>0.21) in 21 of 23 subjects (91%), and the scores for 3 (13%) suggested cirrhosis (>0.74). HA suggested cirrhosis (>46 ng/mL) in 3 of 17 subjects (18%). One subject died during the collection period. Eleven of 26 subjects (42%) had 4/5 or 5/5 portal fibrosis, consistent with cirrhosis; 17 (63%) had 3/3 sinusoidal fibrosis involving >66% of sinusoids. The FibroSure score and HA levels did not correlate with the degree of hepatic fibrosis and did not predict cirrhosis.

CONCLUSIONS

Abnormal biomarkers of hepatic fibrosis and specimen-proven hepatic fibrosis are common in adults with Fontan circulation. However, FibroSure and HA do not accurately predict the degree of histologic hepatic fibrosis. Further studies are needed to guide strategies for surveillance of liver disease in this population.

Liver Disease in Patients After the Fontan Operation

We reviewed records of all patients with an initial Fontan operation or revision from 1973 to 2012 at our institution (n = 1,138); 195 patients had postoperative liver data available. Cirrhosis was identified by histopathology or characteristic findings on imaging with an associated diagnosis of cirrhosis by a hepatologist. Of 195 patients with biopsy or imaging, 10-, 20-, and 30-year freedom from cirrhosis was 99%, 94%, and 57%, respectively. There were 40 of 195 patients (21%) diagnosed with cirrhosis (mean age at Fontan 10.7 ± 8 years). On multivariate analysis, hypoplastic left heart syndrome was associated with increased risk of cirrhosis (n = 2 of 16, p = 0.0133), whereas preoperative sinus rhythm was protective (p = 0.009). Survival after diagnosis of cirrhosis was 57% and 35%, at 1, and 5 years, respectively. The cause of death was known for 9 patients (5 multiorgan failure, 2 liver failure, and 2 heart failure). In conclusion, there is an incremental occurrence of cirrhosis after the Fontan, which should be considered when designing follow-up protocols for patients after Fontan operation.

Fontan Liver Disease: Review of an Emerging Epidemic and Management Options

OPINION STATEMENT

Adults with complex congenital heart disease that resulted in a Fontan procedure frequently experience late cardiac failure. Increasingly, liver disease is recognized as an important complication of single-ventricle anatomy and Fontan physiology; however, there is no consensus regarding liver evaluation in this population. Here, we review what is known about liver disease in this unique group and propose screening and prevention measures. We also review controversial treatment areas including assist devices and transplantation, with a review of outcomes in isolated heart and combined heart-liver transplant.

Risk factors and serological markers of liver cirrhosis after Fontan procedure

Liver cirrhosis (LC), which may result in hepatic failure or cancer, has been reported in patients after Fontan procedure. The purpose of this study was to clarify the frequency and histological characteristics of LC, and to evaluate the risk factors and serological markers of LC with Fontan circulation. Retrospective review of contrast-enhanced CT scans (CT) of the liver was carried out in 57 patients after Fontan procedure. Patients were divided into two groups: LC group (n = 31) and no LC group (n = 26). Age at Fontan procedure, duration after Fontan procedure, catheterization data, and history of failing Fontan circulation were compared between groups. Serological data including γ-GTP and hyaluronic acid were compared. Histology of autopsy specimens was assessed when available. Duration after Fontan procedure was significantly longer in LC group than no LC group. History of failing Fontan circulation was more frequent in LC group than in no LC group. There was no correlation between type of procedure (APC/Bjork/lateral tunnel/TCPC) and LC in this series. Serum hyaluronic acid, γ-GTP, and Forns index were significantly higher in LC group. Significant risk factors for LC were duration after Fontan procedure (>20 years). In autopsy specimens, histopathological changes of LC were observed predominantly in the central venous area. LC diagnosed with CT is frequent in patients long after Fontan procedure, especially after 20 years. Hyaluronic acid and γ-GTP could be useful markers to monitor the progression of liver fibrosis in Fontan patients.

Magnetic Resonance Elastography: A Novel Technique for the Detection of Hepatic Fibrosis and Hepatocellular Carcinoma After the Fontan Operation

OBJECTIVE

To evaluate the utility of magnetic resonance elastography (MRE) in screening patients for hepatic fibrosis, cirrhosis, and hepatocellular carcinoma after the Fontan operation.

PATIENTS AND METHODS

Hepatic MRE was performed in conjunction with cardiac magnetic resonance imaging in patients who had undergone a Fontan operation between 2010 and 2014. Liver stiffness was calculated using previously reported techniques. Comparisons to available clinical, laboratory, imaging, and histopathologic data were made.

RESULTS

Overall, 50 patients at a median age of 25 years (range, 21-33 years) who had undergone a Fontan operation were evaluated. The median interval between Fontan operation and MRE was 22 years (range, 16-26 years). The mean liver stiffness values were increased: 5.5 ± 1.4 kPa relative to normal participants. Liver stiffness directly correlated with liver biopsy-derived total fibrosis score, time since operation, mean Fontan pressure, γ-glutamyltransferase level, Model for End-Stage Liver Disease score, creatinine level, and pulmonary vascular resistance index. Liver stiffness was inversely correlated with cardiac index. All 3 participants with hepatic nodules exhibiting decreased contrast uptake on delayed postcontrast imaging and increased nodule stiffness had biopsy-proven hepatocellular carcinoma.

CONCLUSION

The association between hepatic stiffness and fibrosis scores, Model for End-Stage Liver Disease scores, and γ-glutamyltransferase level suggests that MRE may be useful in detecting (and possibly quantifying) hepatic cirrhosis in patients after the Fontan operation. The correlation between stiffness and post-Fontan time interval, mean Fontan pressure, pulmonary vascular resistance index, and reduced cardiac index suggests a role for long-term hepatic congestion in creating these hepatic abnormalities. Magnetic resonance elastography was useful in detecting abnormal nodules ultimately diagnosed as hepatocellular carcinoma. The relationship between stiffness with advanced fibrosis and hepatocellular carcinoma provides a strong argument for additional study and broader application of MRE in these patients.

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.

Impact of liver disease after the fontan operation

Liver disease is being reported with increased frequency in survivors of the Fontan operation. The clinical impact of structural hepatic abnormalities in these patients remains largely unknown. We sought to assess if, and how, cardiologists are screening for hepatic disease in these patients to evaluate for clinical or laboratory correlates of structural hepatic disease and determine the prevalence and clinical impact of such disease. Retrospective data analysis from tertiary institutions was performed. Hepatic imaging studies and serology performed over the last decade were reviewed and clinical and laboratory correlates of structural hepatic alterations on liver imaging or biopsy were sought. Outcomes were determined. In this cohort study, 53 of 60 adult survivors (88%) underwent hepatic imaging with computed tomography, magnetic resonance imaging, or ultrasound with a median number of 2 (0 to 10) studies over the past decade. The frequency of hepatic imaging varied widely with 70% of patients undergoing serial studies. Cirrhosis with or without abnormal hepatic nodules was seen in 29 of 53 patients (55%) at 18.4 ± 5.6 years after the Fontan procedure. Adverse hepatic-related outcome occurred in 22% of the entire patient cohort and was unrelated to time from Fontan operation. In conclusion, there exists significant variability in the type and timing of testing for hepatic complications after the Fontan procedure. Structural hepatic alterations are common and can be associated with significant morbidity and mortality. Routine imaging, and serologic evaluation, is recommended in all Fontan survivors.

Outcomes of a Hepatitis C Screening Protocol in At-Risk Adults With Prior Cardiac Surgery

Background:

Symptoms associated with hepatitis C infection often do not develop until an advanced stage of liver disease. Prior to 1992, reliable testing for hepatitis C was unavailable, resulting in potential patient exposure during cardiopulmonary bypass. As the hepatitis C prevalence in our center was unknown, a screening protocol for patients who underwent surgery prior to 1992 was developed.

Methods:

Patients evaluated in the Wisconsin Adult Congenital Heart Disease program who underwent surgery prior to 1992 were screened for hepatitis C as part of their initial clinical evaluation. The hepatitis C-positive patients were assessed for risk factors, level of hepatic involvement, whether they received treatment, and whether viral clearance was obtained.

Results:

A total of 147 patients (53% male) underwent testing. Seven (4.8%) patients had evidence of chronic hepatitis C infection, which is higher than the Wisconsin reported prevalence of 0.3%. Six of the seven patients had elevated liver enzymes at time of diagnosis. No relationship was found between hepatitis C infection and number of surgeries, year of surgery, or age at surgery. Four patients had hepatitis C genotype 1, but none achieved viral clearance despite three having received treatment. Three had genotype 2, were treated, and had viral clearance. No hepatitis C-positive patient developed cirrhosis or required liver transplant.

Conclusion:

Hepatitis C infection in patients with congenital heart disease who underwent surgical palliation prior to 1992 is common, with prevalence higher than the general population. Our data emphasize the continued importance of screening the high-risk adult congenital heart disease patients.

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 Circulation in Adult Patients

Objective:

The development of liver fibrosis and cirrhosis due to long-standing liver congestion is known to occur in adult patients with Fontan circulation. Hepatic elastography has shown to be a useful tool for the noninvasive assessment and staging of liver fibrosis in chronic liver diseases, although the utility of this technique in Fontan patients remains to be adequately studied.

Methods:

Twenty-one patients with Fontan circulation underwent an abdominal ultrasound and an acoustic radiation force impulse (ARFI) elastography. In order to compare the results from this group, a cohort of 14 healthy controls and another group containing 17 patients with cirrhosis were included. The association between the velocity values measured with elastography and clinical and analytical parameters were also studied.

Results:

Mean shear waves propagation velocity in liver tissue in the Fontan group was 1.86 ± 0.5 m/s, with 76% of patients over the cirrhosis threshold (1.55 m/s). The control group had a mean velocity of 1.09 ± 0.06 m/s, while the cirrhotic group obtained 2.71 ± 0.51 m/s. Seven patients with Fontan circulation had increased liver enzymes. Liver ultrasound showed evidence of chronic liver disease in six patients. Velocity values obtained in the presence or absence of analytical or liver ultrasound abnormalities showed significant differences in the univariate analysis ( P = .04 and P = .03 respectively).

Conclusion:

In conclusion, ARFI elastography showed increased wave propagation velocity values in the Fontan population suggesting increased liver stiffness which could be related to advanced fibrosis. A statistically significant association between ARFI values and the presence of analytical and ultrasound abnormalities has been demonstrated.

Congestive hepatopathy after Fontan operation and related factors assessed by transient elastography

OBJECTIVE

Congestive hepatopathy after a Fontan operation can have a major effect on long-term morbidity. We evaluated congestive hepatopathy in patients with Fontan circulation using transient elastography to determine which risk factors for hepatopathy are related to liver stiffness (LS).

METHODS

We evaluated 46 patients with Fontan circulation and 26 with right side heart failure (RHF) and hepatic congestion using laboratory tests, the aspartate aminotransferase-to-platelet ratio index, ultrasonography, and transient elastography.

RESULTS

The LS value was significantly greater in the Fontan group (21.1±8.0 kPa) than in the RHF group (10.0±9.0 kPa). The total bilirubin and albumin serum levels, white blood cell count, and aspartate aminotransferase to platelet ratio index correlated significantly with LS in the Fontan group. Of the risk factors, age at evaluation (r=0.42, P=.004), age at Fontan completion (r=0.51, P<.001), inferior vena cava diameter (r=0.35, P=.02), and spleen size (r=0.53, P=.002) correlated significantly with LS. Nineteen patients in the Fontan group (41.3%) had abnormal ultrasound findings, and the frequency of abnormal findings increased with increasing LS (P=.002). In the subgroup with the greatest LS value (≥30 kPa), 88.9% had abnormal ultrasound findings and 44.4% liver cirrhosis. Multivariate analysis revealed that age at Fontan procedure completion and total bilirubin were independent risk factors for hepatopathy.

CONCLUSIONS

The present study revealed that congestive hepatopathy developed in a significant fraction of patients with long-term Fontan circulation and that transient elastography could be an easy and useful method to assess congestive hepatopathy in these patients.

Feeding dysfunction in children with single ventricle following staged palliation

OBJECTIVE

To determine the prevalence of feeding dysfunction in children with single ventricle defects and identify associated risk factors.

STUDY DESIGN

Patients aged 2-6 years with single ventricle physiology presenting for routine cardiology follow-up at the Children's Hospital of Wisconsin were prospectively identified. Parents of the patients completed 2 validated instruments for assessment of feeding dysfunction. Chart review was performed to retrospectively obtain demographic and diagnostic data.

RESULTS

Instruments were completed for 56 patients; median age was 39 months. Overall, 28 (50%) patients had some form of feeding dysfunction. Compared with a normal reference population, patients with single ventricle had statistically significant differences in dysfunctional food manipulation (P < .001), mealtime aggression (P = .002), choking/gagging/vomiting (P < .001), resistance to eating (P < .001), and parental aversion to mealtime (P < .001). Weight and height for age z-scores were significantly lower in subjects with feeding dysfunction (-0.84 vs -0.33; P < .05 and -1.46 vs -0.56; P = .001, respectively). Multivariable analysis identified current gastrostomy tube use (P = .02) and a single parent household (P = .01) as risk factors for feeding dysfunction.

CONCLUSION

Feeding dysfunction is common in children with single ventricle defects, occurring in 50% of our cohort. Feeding dysfunction is associated with worse growth measures. Current gastrostomy tube use and a single parent household were identified as independent risk factors for feeding dysfunction.

Liver cirrhosis in Fontan patients does not affect 1-year post-heart transplant mortality or markers of liver function

BACKGROUND

Liver cirrhosis is recognized with long-term follow-up of patients after the Fontan procedure. The effect of liver cirrhosis on the use of heart transplant (HT) and on post-HT outcomes is unknown.

METHODS

We reviewed Fontan patients evaluated for HT from 2004 to 2012 with hepatic computed tomography (CT) imaging, classified as normal, non-cirrhotic changes, or cirrhosis. The primary outcome was 1-year all-cause mortality, and the secondary outcome was differences in serial post-HT liver evaluation.

RESULTS

CT imaging in 32 Fontan patients evaluated for HT revealed 20 (63%) with evidence of liver disease, including 13 (41%) with cirrhosis. Twenty underwent HT, including 5 non-cirrhotic and 7 cirrhosis patients. Characteristics at listing between normal or non-cirrhotic (n = 13) and cirrhosis (n = 7) groups were similar, except cirrhosis patients were older (median 17.6 vs 9.6 years, p = 0.002) and further from Fontan (median 180 vs 50 months, p < 0.05). Serial liver evaluation was similar, including aspartate aminotransferase, alanine aminotransferase, bilirubin, albumin, and tacrolimus dose at 1, 3, 6, 9, and 12 months. Overall patient survival was 80% at 1 year, with no difference between cirrhosis and non-cirrhosis patients (86% vs 77%, p = 0.681). Liver biopsies were performed in 7 patients before HT, and all specimens showed architectural changes with bridging fibrosis.

CONCLUSIONS

Most patients evaluated for HT had abnormal liver findings by CT, with cirrhosis in 41%. One-year mortality and serial liver evaluation were similar between groups after HT. Liver cirrhosis identified by CT imaging may not be an absolute contraindication to HT alone in this population.

The adult with a fontan: a panacea without a cure? Review of long-term complications

The univentricular heart includes a spectrum of complex cardiac defects that are managed by staged palliative surgical procedures, ultimately resulting in a Fontan procedure. Since 1971, when it was first developed, the procedure has undergone several variations. These patients require lifelong management, including a thorough knowledge of their anatomic substrate, hemodynamic status, management of rhythm and ventricular function, together with multi-organ evaluation. As these patients enter middle age, there is increasing awareness of long-term complications and mortality. This review highlights the concept behind the staged surgical palliations, the unique single ventricle physiology and the long-term complications in this complex cohort of patients.

Extracardiac complications in adults with congenital heart disease

With the increasing number of adults living with repaired, or unrepaired, congenital heart disease, there is a growing incidence of extracardiac comorbidities. These comorbidities can affect various organ systems in complex ways, and may have a significant impact on a patient's quality of life and survival. Many of these potential complications may go undiagnosed until there is already a significant bearing on the patient's life. Therefore, it is important for physicians who care for the adult congenital patient to be mindful of these potential extracardiac complications, and actively assess for these complications in their adult congenital practice. Continued research to identify modifiable risk factors is needed so that both preventative and therapeutic management options for these extracardiac complications may be developed.