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

Evaluating the Longevity of the Fontan Pathway

Children born with single ventricle physiology who undergo Fontan palliation face a diverse set of long-term complications. However, patient follow-up has in large part been limited to single institutional experiences without uniform application of diagnostic modalities to screen for relevant outcomes. Additionally, the use of different graft materials and variable surgical technique as part of the Fontan procedure has further complicated the evaluation of single ventricle patients. The purpose of this review is to define the changes in the Fontan pathway specific to the graft material used and its relationship to patient outcomes. As a means of introduction, we briefly review the historical evolution of the Fontan procedure with a focus on the intent behind design changes and incorporation of different biomaterials. We further delineate changes to the Fontan pathway which include the development of stenosis, differential growth, thrombosis, and calcification. Ultimately, the recognition of the changes noted within the Fontan pathway need to be assessed relative to their impact on patient hemodynamics, functional capacity, and Fontan-associated comorbidities.

Fontan-Associated Liver Disease: Screening, Management, and Transplant Considerations

Surgical innovation and multidisciplinary management have allowed children born with univentricular physiology congenital heart disease to survive into adulthood. An estimated global population of 70 000 patients have undergone the Fontan procedure and are alive today, most of whom are <25 years of age. Several unexpected consequences of the Fontan circulation include Fontan-associated liver disease. Surveillance biopsies have demonstrated that virtually 100% of these patients develop clinically silent fibrosis by adolescence. As they mature, there are increasing reports of combined heart-liver transplantation resulting from advanced liver disease, including bridging fibrosis, cirrhosis, and hepatocellular carcinoma, in this population. In the absence of a transplantation option, these young patients face a poor quality of life and overall survival. Acknowledging that there are no consensus guidelines for diagnosing and monitoring Fontan-associated liver disease or when to consider heart transplantation versus combined heart-liver transplantation in these patients, a multidisciplinary working group reviewed the literature surrounding Fontan-associated liver disease, with a specific focus on considerations for transplantation.

Occurrence of a primary liver cancer with an unusual histologic appearance as a late Fontan complication

The Fontan procedure is an open heart procedure performed in pediatric patients with a particular congenital cardiac anomaly known as a univentricular heart. The procedure is used to reroute the systemic venous blood from the inferior vena cava directly to the pulmonary artery. It improves patients' prognoses, but various late-phase extracardiac complications that manifest when patients reach adolescence have been recognized. These complications, pulmonary arteriovenous fistula and protein losing gastroenteropathy, for example, present significant challenges in the management of adults with Fontan circulation. Liver fibrosis is another possible late-phase complication and one of the most serious. Development of a neoplasm, usually a hepatocellular carcinoma, is sometimes reported. We encountered a young patient in whom Fontan circulation led to the development of a histologically unusual liver cancer that resembled the poorly differentiated hepatocellular carcinoma or the combined hepatocellular-cholangiocarcinoma with stem-cell features described in the latest WHO classification.

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.

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.

Posterior Circulation Ischemia or Occlusion in Five Adults With Failing Fontan Circulation

BACKGROUND

Palliative procedures performed before the Fontan procedure may require ligation of the subclavian arteries, thereby affecting flow to the vertebral arteries. In adults with functionally univentricular heart disease, the implications of altered brainstem vascular anatomy for perioperative management of failing Fontan circulation are not known.

METHODS

We identified abnormal posterior circulation anatomy in an adult patient with failing Fontan circulation who experienced a brainstem stroke after Fontan conversion. We then changed our clinical practice to include detailed preoperative neurologic evaluation of adults with univentricular heart disease and failing Fontan circulation. Here, we report the clinical and neuroimaging findings in 5 consecutive patients before and after this change in practice.

RESULTS

Five patients ages 28 to 42 years had Fontan procedures performed in childhood, and underwent either Fontan conversion or cardiac transplantation. Patient 1 experienced an episode of decreased cerebral perfusion pressure on postoperative day 3, and experienced an ischemic brainstem stroke causing transient locked-in syndrome. A change in practice was made, and patients 2, 3, and 4 were evaluated preoperatively by the neurocritical care service. These patients then had higher target blood pressures perioperatively and no neurologic injury. Patient 5 was evaluated for symptoms consistent with subclavian steal. Neuroimaging in 3 patients was abnormal, with atrophic vertebral arteries, an occluded vertebral artery, and retrograde perfusion of a vertebral artery.

CONCLUSIONS

In adults with failing Fontan circulation there is a potential for neurologic complications as a result of venous congestion with elevated central venous pressures, and aberrant posterior circulation. The patient's history and brain imaging may be used to identify at-risk patients and to tailor perioperative management during Fontan conversion or heart transplantation to mitigate the risk for brainstem ischemia.

High Overweight and Obesity in Fontan Patients: A 20-Year History

The prevalence of obesity in long-term survivors with complex congenital heart disease may be increasing, and little is known about the timing and onset of weight gain and growth patterns in these high-risk patients. Prevalence rates of overweight/obesity and longitudinal changes in body mass index (BMI) with age were determined in 606 patients with Fontan circulation seen at a tertiary care cardiology center from 1992 to 2012. The number of clinic encounters (n) was stratified by age group (n = 401, 2-5 years; n = 333, 6-11 years; n = 217, 12-19 years; and n = 129, >20 years). Among adults, 39% were overweight/obese at last clinic visit; 22% overweight, and 17% obese. Childhood anthropometric data were available for 82 adults, of which 15% (n = 12/82) were overweight/obese in childhood. The likelihood of being overweight/obese as an adult was three times higher if there was a BMI ≥ 85th percentile in childhood (CI 2.1-4.5, P < 0.01). Overweight/obesity in adulthood was associated with lower heart failure rates (4 vs. 19%, P = 0.03). Pediatric rates of overweight/obesity were comparable to national data (NHANES 2011-2012) in every age group: at 2-5 years, (25 vs. 23%), 6-11 years (26 vs. 34%), and 12-19 years (15 vs. 35%). Systolic blood pressure was higher in overweight/obese children as young as 2-5 years of age. Childhood and adult survivors with Fontan circulation have high rates of overweight/obesity. Childhood obesity is a strong predictor of future adiposity and is linked to changes in systolic blood pressure at a very young age.

Umbilical neutrophil gelatinase-associated lipocalin level as an early predictor of acute kidney injury in neonates with hypoplastic left heart syndrome

Acute kidney injury (AKI) is a primarily described complication after unbalanced systemic perfusion in neonates with congenital heart defects, including hypoplastic left heart syndrome (HLHS). The aim of the study was to compare the umbilical NGAL concentrations between neonates born with HLHS and healthy infants, as well as to analyze whether the determination of NGAL level could predict AKI in neonates with prenatally diagnosed HLHS. Twenty-one neonates with prenatally diagnosed HLHS were enrolled as study group and 30 healthy neonates served as controls. Perinatal characteristics and postnatal parameters were extracted from the hospital neonatal database. In umbilical cord blood, we determined plasma NGAL concentrations, acid base balance, and lactate and creatinine levels. In neonates with HLHS, complications (respiratory insufficiency, circulatory failure, NEC, IVH, and AKI) were recorded until the day of cardiosurgery. We observed in neonates with HLHS higher umbilical NGAL levels compared to controls. Among 8 neonates with HLHS and diagnosed AKI stage 1, we observed elevated NGAL levels in comparison to those newborns without AKI. Umbilical NGAL could predict, with high sensitivity and specificity, AKI development in study neonates. We suggest that the umbilical blood NGAL concentration may be an early marker to predict AKI in neonates with HLHS.

Pediatric heart transplantation-indications and outcomes in the current era

Pediatric heart transplantation (HTx) remains an important treatment option in the care of children with end-stage heart disease, whether it is secondary to cardiomyopathy or congenital heart disease (CHD). As surgical outcomes for CHD have improved, the indications for pediatric HTx have had to be dynamic, not only for children with CHD but also for the growing population of adults with CHD. As the field of pediatric HTx has evolved, the outcomes for children undergoing HTx have improved. This is undoubtedly due to the continued research efforts of both single-center studies, as well as research collaboratives such as the International Society for Heart and Lung Transplantation (ISHLT) and the Pediatric Heart Transplant Study (PHTS) group. Research collaboratives are increasingly important in pediatric HTx as single center studies for a limited patient population may not elicit strong enough evidence for practice evolution. Similarly, complications that limit the long term graft survival may occur in a minority of patients thus pooled experience is essential. This review focuses on the indications and outcomes for pediatric HTx, with a special emphasis on studies generated by these research collaboratives.

Pediatric heart transplantation-indications and outcomes in the current era

Pediatric heart transplantation (HTx) remains an important treatment option in the care of children with end-stage heart disease, whether it is secondary to cardiomyopathy or congenital heart disease (CHD). As surgical outcomes for CHD have improved, the indications for pediatric HTx have had to be dynamic, not only for children with CHD but also for the growing population of adults with CHD. As the field of pediatric HTx has evolved, the outcomes for children undergoing HTx have improved. This is undoubtedly due to the continued research efforts of both single-center studies, as well as research collaboratives such as the International Society for Heart and Lung Transplantation (ISHLT) and the Pediatric Heart Transplant Study (PHTS) group. Research collaboratives are increasingly important in pediatric HTx as single center studies for a limited patient population may not elicit strong enough evidence for practice evolution. Similarly, complications that limit the long term graft survival may occur in a minority of patients thus pooled experience is essential. This review focuses on the indications and outcomes for pediatric HTx, with a special emphasis on studies generated by these research collaboratives.