Heart Transplantation in Children after a Fontan Procedure: Better than People Think

International Society for Heart and Lung Transplantation Guidelines for the Evaluation and Care of Cardiac Transplant Candidates-2024

The "International Society for Heart and Lung Transplantation Guidelines for the Evaluation and Care of Cardiac Transplant Candidates-2024" updates and replaces the "Listing Criteria for Heart Transplantation: International Society for Heart and Lung Transplantation Guidelines for the Care of Cardiac Transplant Candidates-2006" and the "2016 International Society for Heart Lung Transplantation Listing Criteria for Heart Transplantation: A 10-year Update." The document aims to provide tools to help integrate the numerous variables involved in evaluating patients for transplantation, emphasizing updating the collaborative treatment while waiting for a transplant. There have been significant practice-changing developments in the care of heart transplant recipients since the publication of the International Society for Heart and Lung Transplantation (ISHLT) guidelines in 2006 and the 10-year update in 2016. The changes pertain to 3 aspects of heart transplantation: (1) patient selection criteria, (2) care of selected patient populations, and (3) durable mechanical support. To address these issues, 3 task forces were assembled. Each task force was cochaired by a pediatric heart transplant physician with the specific mandate to highlight issues unique to the pediatric heart transplant population and ensure their adequate representation. This guideline was harmonized with other ISHLT guidelines published through November 2023. The 2024 ISHLT guidelines for the evaluation and care of cardiac transplant candidates provide recommendations based on contemporary scientific evidence and patient management flow diagrams. The American College of Cardiology and American Heart Association modular knowledge chunk format has been implemented, allowing guideline information to be grouped into discrete packages (or modules) of information on a disease-specific topic or management issue. Aiming to improve the quality of care for heart transplant candidates, the recommendations present an evidence-based approach.

The Fontan immunophenotype and post-transplant outcomes in children: A multi-institutional study

BACKGROUND

Patients after Fontan palliation represent a growing pediatric population requiring heart transplant (HTx) and often have lymphopenia (L) and/or hypogammaglobinemia that may be exacerbated by protein-losing enteropathy (PLE, P). The post-HTx effects of this altered immune phenotype are not well studied.

METHODS

In this study of the Pediatric Heart Transplant Society Registry, 106 Fontan patients who underwent HTx between 2005 and 2018 were analyzed. The impact of lymphopenia and PLE on graft survival, infection, rejection, and malignancy was analyzed at 1 and 5 years post-HTx.

RESULTS

The following combinations of lymphopenia and PLE were noted: +L+P, n = 37; +L-P, n = 23; -L+P, n = 10; and -L-P, n = 36. Graft survival between the groups was similar within the first year after transplant (+L+P: 86%, +L-P: 86%, -L+P: 87%, -L-P: 89%, p = .9). Freedom from first infection post-HTx was greatest among -L-P patients compared to patients with either PLE, lymphopenia, or both; with a 22.1% infection incidence in the -L-P group and 41.4% in all others. These patients had a significantly lower infection rate in the first year after HTx (+L+P: 1.03, +L-P: 1, -L+P: 1.3, -L-P: 0.3 infections/year, p < .001) and were similar to a non-single ventricle CHD control group (0.4 infections/year). Neither freedom from rejection nor freedom from malignancy 1 and 5 years post-HTx, differed among the groups.

CONCLUSIONS

Fontan patients with altered immunophenotype, with lymphopenia and/or PLE, are at increased risk of infection post-HTx, although have similar early survival and freedom from rejection and malignancy. These data may encourage alternative immunosuppression strategies and enhanced monitoring for this growing subset of patients.

Fontan-associated liver disease: Diagnosis, surveillance, and management

The Fontan operation is a lifesaving procedure for patients with functional single-ventricle congenital heart disease, where hypoplastic left heart syndrome is the most frequent anomaly. Hemodynamic changes following Fontan circulation creation are now increasingly recognized to cause multiorgan affection, where the development of a chronic liver disease, Fontan-associated liver disease (FALD), is one of the most important morbidities. Virtually, all patients with a Fontan circulation develop liver congestion, resulting in fibrosis and cirrhosis, and most patients experience childhood onset. FALD is a distinctive type of congestive hepatopathy, and its pathogenesis is thought to be a multifactorial process driven by increased nonpulsatile central venous pressure and decreased cardiac output, both of which are inherent in the Fontan circulation. In the advanced stage of liver injury, complications of portal hypertension often occur, and there is a risk of developing secondary liver cancer, reported at young age. However, FALD develops with few clinical symptoms, a surprisingly variable degree of severity in liver disease, and with little relation to poor cardiac function. The disease mechanisms and modifying factors of its development are still not fully understood. As one of the more important noncardiac complications of the Fontan circulation, FALD needs to be diagnosed in a timely manner with a structured monitoring scheme of disease development, early detection of malignancy, and determination of the optimal time point for transplantation. There is also a clear need for consensus on the best surveillance strategy for FALD. In this regard, imaging plays an important role together with clinical scoring systems, biochemical workups, and histology. Patients operated on with a Fontan circulation are generally followed up in cardiology units. Ultimately, the resulting multiorgan affection requires a multidisciplinary team of healthcare personnel to address the different organ complications. This article discusses the current concepts, diagnosis, and management of FALD, with special emphasis on the role of different imaging techniques in the diagnosis and monitoring of disease progression, as well as current recommendations for liver disease surveillance.

Expanding heart transplantation in 2022 and beyond

PURPOSE OF REVIEW

Despite advances in the technology of mechanical circulatory support, the need for heart transplantation continues to grow. The longevity of heart transplants continues to be superior to mechanical solutions, though the short-term differences are shrinking. In this review, we cover three timely developments and summarize the recent literature.

RECENT FINDINGS

After stagnant rates of heart transplant activity for some years, recently, transplant volume has increased. The developments that have ignited interest have been the use of hepatitis C infected donors, which can now be safely transplanted with the advent of curative oral regimens, and the worldwide use of donors following withdrawal of life support as opposed to traditional brain death donors. In addition, the recent experience of human cardiac xenotransplantation has been very exciting, and though it is not of clinical utility yet, it holds the promise for a virtually unlimited supply of organs at some time in the future.

SUMMARY

Much work remains to be done, but together, all three of these developments are exciting and important to be aware of in the future. Each will contribute to additional donors for human heart transplantation and hopefully will alleviate suffering and death on the waiting list.

Failures of the Fontan System in Univentricular Hearts and Mortality Risk in Heart Transplantation: A Systematic Review and Meta-Analysis

The Fontan procedure (FP) is the standard surgical treatment for Univentricular heart diseases. Over time, the Fontan system fails, leading to pathologies such as protein-losing enteropathy (PLE), plastic bronchitis (PB), and heart failure (HF). FP should be considered as a transitional step to the final treatment: heart transplantation (HT). This systematic review and meta-analysis aims to establish the risk of death following HT according to the presence of FP complications. There was a total of 691 transplanted patients in the 18 articles, immediate survival 88% (n = 448), survival from 1 to 5 years of 78% (n = 427) and survival from 5.1 to 10 years of 69% (n = 208), >10 years 61% (n = 109). The relative risk (RR) was 1.12 for PLE (95% confidence interval [CI] = 0.89-1.40, p = 0.34), 1.03 for HF (0.7-1.51, p = 0.88), 0.70 for Arrhythmias (0.39-1.24, p = 0.22), 0.46 for PB (0.08-2.72, p = 0.39), and 5.81 for CKD (1.70-19.88, p = 0.005). In patients with two or more failures, the RR was 1.94 (0.99-3.81, p = 0.05). After FP, the risk of death after HT is associated with CKD and with the presence of two or more failures.

Surgical management of failing Fontan circulation: results from 30 cases with 285 patient-years follow-up

OBJECTIVES

Fontan patients are known to suffer from clinical attrition over the years, which has been characterized as Fontan failure. We sought to evaluate the clinical outcomes of such Fontan patients undergoing surgical management in a 25-year, single-centre experience.

METHODS

A retrospective single-centre analysis of patients undergoing surgical treatment for failing Fontan between 1995 and 2020, including any reoperations when ventricular function was preserved, or a heart transplant (HTx), when ventricular contractility was impaired. We analysed survival, indications for surgery and early and late complication rates.

RESULTS

We collected 30 patients (mean age 24.7 years) who required surgery after a mean time of 19.3 years from the original Fontan procedure: Fontan conversion in 21 (70%, extracardiac conduit in 19, lateral tunnel in 2), a HTx in 4 (13.3%) and other reoperations in 5 (16.7%). The most common indications for surgery were tachyarrhythmias (63.3%) and severe right atrial dilatation (63.3%). Overall survival at the 1-, 5-, 10- and 20-year follow-up examinations were 75.9% [95% confidence interval (CI): 91.4-60.4%], 75.9% (95% CI: 91.4-60.4%), 70% (95% CI: 78-52%) and 70% (95% CI: 78-52%), respectively. The most frequent complications were postoperative tachyarrhythmias (50%) and late Fontan-associated liver disease (56.5%). HTx and Fontan conversion provided comparably good outcomes compared to other reoperations (P = 0.022).

CONCLUSIONS

Surgery for failing Fontan can be performed effectively with overall good long-term survival. However, early and late morbidities are still a significant burden. Because other reoperations performed when patients presented with contraindications for a HTx have carried high mortality, close clinical follow-up is mandatory, and an earlier indication for Fontan conversion or a HTx is advisable to optimize outcomes.

Intrahepatic Dynamic Contrast-Enhanced Magnetic Resonance Lymphangiography: Potential Imaging Signature for Protein-Losing Enteropathy in Congenital Heart Disease

Background

Protein‐losing enteropathy (PLE) is a significant cause of morbidity and mortality in congenital heart disease patients with single ventricle physiology. Intrahepatic dynamic contrast‐enhanced magnetic resonance lymphangiography (IH‐DCMRL) is a novel diagnostic technique that may be useful in characterizing pathologic abdominal lymphatic flow in the congenital heart disease population and in diagnosing PLE. The objective of this study was to characterize differences in IH‐DCMRL findings in patients with single ventricle congenital heart disease with and without PLE.

Methods and Results

This was a single‐center retrospective study of IH‐DCMRL findings and clinical data in 41 consecutive patients, 20 with PLE and 21 without PLE, with single ventricle physiology referred for lymphatic evaluation. There were 3 distinct duodenal imaging patterns by IH‐DCMRL: (1) enhancement of the duodenal wall with leakage into the lumen, (2) enhancement of the duodenal wall without leakage into the lumen, and (3) no duodenal involvement. Patients with PLE were more likely to have duodenal involvement on IH‐DCMRL than patients without PLE (P<0.001).

Conclusions

IH‐DCMRL findings of lymphatic enhancement of the duodenal wall and leakage of lymph into the duodenal lumen are associated with PLE. IH‐DCMRL is a useful new modality for characterizing pathologic abdominal lymphatic flow in PLE and might be useful as a risk‐assessment tool for PLE in at‐risk patients.

Pathways to Clinical Cardiac Xenotransplantation

Heart transplantation is the only long-lasting lifesaving option for patients with terminal cardiac failure. The number of available human organs is however far below the actual need, resulting in substantial mortality of patients while waiting for a human heart. Mechanical assist devices are used to support cardiac function but are associated with a high risk of severe complications and poor quality of life for the patients. Consistent success in orthotopic transplantation of genetically modified pig hearts into baboons indicates that cardiac xenotransplantation may become a clinically applicable option for heart failure patients who cannot get a human heart transplant. In this overview, we project potential paths to clinical cardiac xenotransplantation, including the choice of genetically modified source pigs; associated requirements of microbiological, including virological, safety; optimized matching of source pig and recipient; and specific treatments of the donor heart after explantation and of the recipients. Moreover, selection of patients and the regulatory framework will be discussed.

A Review of Physiologic Considerations and Challenges in Pediatric Patients With Failing Single- Ventricle Physiology Undergoing Ventricular Assist Device Placement

Advances in surgical techniques and outpatient cardiac care have led to a growing population of pediatric patients surviving well into adulthood with previous single-ventricle palliation. Continued improvement in survival has resulted in subsequent increases in the number of patients with single-ventricle physiology listed for heart transplantations. Some of these patients require mechanical circulatory support as a bridge to transplantation, although establishing successful mechanical circulatory support in these complex patients remains challenging. Only limited published data exist describing the perioperative anesthetic management and key considerations dedicated to patients with failing single-ventricle physiology presenting for ventricular assist devices. This clinical review aims to provide a focused evaluation of the vital perioperative considerations encountered in this novel population.

Technical modifications for transplant in the failing Fontan

INTRODUCTION

Heart transplant after Fontan completion poses a unique surgical challenge. Twenty patients are presented, stressing the technical hints performed in the five anastomoses to match the graft in the recipient.

METHODS

Data are collected from 20 Fontan patients between 2013 and 2019. Age (13 years), weight (37 kg.), and time interval between Fontan and transplant (7 years) are presented as median. Extracardiac conduit (size 18/20) was implanted in 15 patients, whereas atrio-pulmonary connection was performed in 4 and lateral tunnel in 1. Six patients developed protein-losing enteropathy. Seventeen stents had been previously deployed.

RESULTS

The five anastomoses underwent some changes. Left atrium once, aorta 9 times, superior vena cava 7 times, pulmonary branches 15 times, and inferior vena cava 12 times. Follow-up was complete for a median of 42 months (range 6-84). Two patients died. ECMO was needed in six cases for pulmonary hypertension. Four patients had collateral vessels occluded in the cath lab, and stents were placed in superior vena cava (1) and aorta (1) post-transplant. Protein-losing enteropathy was resolved in five patients. Interestingly, one patient was on a systemic assist device before transplant (Levitronix) and right assistance (ECMO) afterwards.

CONCLUSIONS

Transplant in Fontan patients is actually challenging. Hints in every of the five proposed anastomoses must be anticipated, including stents removal. Extra tissue from the donor (innominate vein, aortic arch, and pericardium) is strongly advisable. ECMO for right ventricular dysfunction was needed in nearly one-third of the cases. Overall results can match other transplant cohorts.

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.

Budesonide for Protein Losing Enteropathy in Patients with Fontan Circulation: A Systematic Review and Meta-Analysis

Background:

Recent studies have shown that oral budesonide can be used to improve albumin level in patients with protein-losing enteropathy (PLE) following Fontan procedure. However, there has never been a systematic review and meta-analysis to confirm this finding. We performed a systematic review and meta-analysis to explore the therapeutic effect of budesonide in patients with PLE post-Fontan procedure.

Methods:

We searched the databases of MEDLINE and EMBASE from inception to January 2019. Included studies were published studies that evaluate albumin level before and after budesonide therapy in patients with PLE following Fontan procedure. Data from each study were combined using the random-effects model.

Results:

Five studies with 36 post-Fontan operation patients with PLE were included. In random-effects model, there was a statistically significant difference in albumin level between before and after budesonide treatment (weighted mean difference = 1.28, 95% confidence interval: 0.76-1.79). No publication bias was observed on a funnel plot and Egger test with a P value of .676.

Conclusions:

The results of this systematic review and meta-analysis show that budesonide can be used to increase albumin level in patients with PLE following Fontan operation. Further studies may focus on the impact of outcome of budesonide in this population.

Transplantation of the failing Fontan

Half a century has passed since the original Fontan palliation. In the interim, surgical and medical advancements have allowed more single ventricle patients to reach Fontan and long-term survival for Fontan patients to improve significantly. However, the risk for Fontan failure and need for heart transplantation remains. In this article we discuss mechanisms of Fontan failure, risk factors and special considerations for Fontan patients in both medical and surgical management around heart transplantation and provide an updated review of survival for Fontan patients after heart transplantation.

Short-term outcomes of en bloc combined heart and liver transplantation in the failing Fontan

Patients with failing Fontan physiology and liver cirrhosis are being considered for combined heart and liver transplantation. We performed a retrospective review of our experience with en bloc combined heart and liver transplantation in Fontan patients > 10 years old from 2006 to 18 per Institutional Review Board approval. Six females and 3 males (median age 20.7, range 14.2-41.3 years) underwent en bloc combined heart and liver transplantation. Indications for heart transplant included ventricular dysfunction, atrioventricular valve regurgitation, arrhythmia, and/or lymphatic abnormalities. Indication for liver transplant included portal hypertension and cirrhosis. Median Fontan/single ventricular end-diastolic pressure was 18/12 mm Hg, respectively. Median Model for End-Stage Liver Disease excluding International Normalized Ratio score was 10 (7-26), eight patients had a varices, ascites, splenomegaly, thrombocytopenia score of ≥ 2, and all patients had cirrhosis. Median cardiopulmonary bypass and donor ischemic times were 262 (178-307) and 287 (227-396) minutes, respectively. Median intensive care and hospital stay were 19 (5-96) and 29 (13-197) days, respectively. Survival was 100%, and rejection was 0% at 30 days and 1 year post-transplant. En bloc combined heart and liver transplantation is an acceptable treatment in the failing Fontan patient with liver cirrhosis.

State of the art of the Fontan strategy for treatment of univentricular heart disease

In patients with a functionally univentricular heart, the Fontan strategy achieves separation of the systemic and pulmonary circulation and reduction of ventricular volume overload. Contemporary modifications of surgical techniques have significantly improved survival. However, the resulting Fontan physiology is associated with high morbidity. In this review, we discuss the state of the art of the Fontan strategy by assessing survival and risk factors for mortality. Complications of the Fontan circulation, such as cardiac arrhythmia, thromboembolism, and protein-losing enteropathy, are discussed. Common surgical and catheter-based interventions following Fontan completion are outlined. We describe functional status measurements such as quality of life and developmental outcomes in the contemporary Fontan patient. The current role of drug therapy in the Fontan patient is explored. Furthermore, we assess the current use and outcomes of mechanical circulatory support in the Fontan circulation and novel surgical innovations. Despite large improvements in outcomes for contemporary Fontan patients, a large burden of disease exists in this patient population. Continued efforts to improve outcomes are warranted. Several remaining challenges in the Fontan field are outlined.

Mechanical Circulatory Support for the Failing Fontan: Conversion to Assisted Single Ventricle Circulation—Preliminary Observations

Background:

Mechanical circulatory support (MCS) of a failing Fontan circulation remains challenging. We hypothesized that MCS can be provided by converting the Fontan circulation into a mechanically assisted single ventricle parallel circulation (MASVC).

Methods:

A porcine model of functionally univentricular circulation was created under cardiopulmonary bypass (CPB) by performing an atrial septectomy, tricuspid valvectomy, and interrupting antegrade pulmonary blood flow. A centrifugal flow pump was placed with inflow from the common atrium. Eight millimeter Dacron grafts anastomosed to the ascending aorta and main pulmonary artery supplied systemic (Qs) and pulmonary (Qp) blood flow. Ultrasonic flow probes were used to measure Qs and Qp after weaning from CPB. The Qp/Qs ratio was regulated using an adjustable clamp. Hemodynamic and laboratory data were recorded.

Results:

All four animals were successfully weaned from CPB onto the MASVC for a duration of two hours. Mechanically assisted single ventricle parallel circulation achieved satisfactory hemodynamics. As anticipated, the arterial oxygen saturation and partial pressure of oxygen in arterial blood were lower in the MASVC compared to baseline biventricular circulation. At the conclusion of the study, there was a trend towards a decrease in the mixed venous saturation with increasing oxygen extraction compared to the baseline. Serum lactate levels increased after weaning from CPB and did not return to baseline after two hours of support.

Conclusion:

Mechanically assisted single ventricle parallel circulation can be established in a single ventricle animal model. This strategy could potentially provide MCS of a single ventricle circulation. Studies with longer duration of support are required to assess adequacy of support and long-term sustainability.

Extracorporeal Membrane Oxygenation (ECMO) Support in Special Patient Populations-The Bidirectional Glenn and Fontan Circulations

Extracorporeal membrane oxygenation (ECMO) is a support modality used within the pediatric cardiac ICU population as a bridge to recovery or decision in the setting of acute myocardial decompensation, support for combined cardiopulmonary failure or in the setting of refractory cardiopulmonary arrest. Patients with univentricular physiology are at particular risk for decompensation requiring ECMO support. This review will focus upon current evidence and techniques for ECMO support of single ventricle patients who have undergone a stage II bidirectional Glenn procedure or the stage III Fontan procedure.

Approaching the 50th anniversary of the first Fontan procedure. What is the current state of treatment provided to patients with functional single ventricles?

Nearly 50 years after the pioneering procedure performed by Francis Fontan and Eugene Baudet, which has saved the lives of thousands of children, there are still more questions than answers regarding therapeutic management. The complex pathophysiology of Fontan circulation, the lack of clear guidelines, and the shift in the care of such patients from pediatric cardiological and cardiac surgical centers to ones dealing with adult patients, cause new threats. This paper outlines the fundamental issues related to the pathophysiology of Fontan circulation and reviews the literature on the methods of treating complications characteristic of this group of patients.

30-year experience of Fontan surgery: single-centre's data

Background

The Fontan procedure has been modified several times since it was introduced into practice in 1968. As many patients now survive to adulthood, attention is directed towards their clinical status and late morbidity. We report our surgical experience of 30 years in Fontan procedures.

Methods

From January 1985 to January 2015, 80 patients underwent Fontan surgery. Twenty-one patients received an atrio-pulmonary Fontan (Group I), four patients underwent total cavopulmonary connection (TCPC) with an intra-atrial lateral tunnel (Group II), six patients received extra-cardiac TCPC with an aortic homograft (group III) and 49 patients received extra-cardiac TCPC with an expanded polytetrafluoroethylene conduit. They were followed for early and late mortality, long-term survival, postoperative morbidity and reoperations.

Results

The mean follow-up time was 7.4 ± 6.6 years. The Kaplan–Meier estimated 15-year survival rate was 42% in Group I, 50% in Group II, 83% in Group III and 94% in Group IV. The median length of stay in intensive care unit, intubation and chest drain stay time were 90 h (IQR, 46–119), 8 h (IQR, 6–16) and 18 days (IQR, 12–28) respectively. Early complications were bleeding (6), taken down of Fontan circulation (3) and acute heart failure managed by left heart bypass (1). Late-occurring morbidities included arrhythmias (6), protein-losing enteropathy (2), thromboembolism (2) and tracheal stenosis (1). Fourteen patients (18%) had redo Fontan procedures.

Conclusion

Our series showed improving results after Fontan completion with excellent mid-term outcome after extra-cardiac TCPC with expanded polytetrafluoroethylene conduit. The long-term result should be followed.