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The Fontan procedure is a palliative surgical intervention designed for patients with single-ventricle physiology, often resulting from congenital heart defects such as tricuspid atresia or hypoplastic left heart syndrome. The procedure involves creating a total cavopulmonary connection, redirecting systemic venous blood to the pulmonary circulation, and bypassing the heart. This staged approach reduces the workload on the single ventricle, allowing it to focus on systemic circulation. While the Fontan procedure significantly improves survival and quality of life, it is associated with long-term complications, including increased systemic venous pressure, arrhythmias, and risks related to pulmonary vascular resistance. This course enhances clinicians' competence in caring for patients undergoing the Fontan procedure by focusing on patient selection, preoperative planning, and postoperative care. Participants learn to identify potential complications and implement evidence-based strategies for long-term management. Emphasis is placed on interprofessional collaboration, with insights into the roles of cardiologists, surgeons, nurses, and other specialists in providing comprehensive care. By fostering teamwork and shared decision-making, the course equips healthcare professionals to improve patient outcomes and address the complex needs of individuals with single-ventricle physiology. Objectives: Identify patients who are appropriate candidates for the Fontan completion procedure based on age, pulmonary pressures, and functional ventricular capacity. Differentiate between various congenital heart defects requiring staged interventions, such as hypoplastic left heart syndrome and tricuspid atresia, and the specific considerations for the Fontan. Assess the potential complications of the Fontan procedure and preventive measures that can be taken to prevent their occurrence. Communicate how careful planning and collaboration among interprofessional team members involved in treating patients undergoing the Fontan procedure will improve outcomes. Access free multiple choice questions on this topic.

The Fontan procedure represents a cornerstone in managing complex congenital heart defects characterized by single-ventricle physiology. Originally described in 1971 by Drs Francis Fontan and Eugène Baudet for tricuspid atresia, the procedure has evolved into the total cavopulmonary connection, offering a palliative treatment option for pediatric patients with single-ventricle congenital heart disease.[1] These conditions, estimated at 0.08 to 0.4 per 1000 live births, are addressed through a staged surgical approach that redirects systemic venous return directly to the pulmonary circulation, bypassing the heart, provided pulmonary pressures are low.[2][3] This optimizes oxygenation and reduces ventricular workload. Advances in surgical techniques and patient selection have improved outcomes, with patients living longer and with a better quality of life.[4] However, morbidity remains significant due to the extracardiac manifestations of Fontan circulation, including challenges in functional status and systemic complications.[2] Ongoing efforts focus on enhancing the understanding of long-term outcomes, addressing disparities, and innovating strategies to reduce complications and improve the quality of life in this growing patient population.[4][5][6] This review explores the historical evolution, surgical techniques, patient selection criteria, and long-term management of Fontan cases, highlighting the challenges and future directions in care.

The Society of Thoracic Surgeons Congenital Heart Surgery Database published in 2017 reported an estimated operative mortality of 1.2% and an average length of stay of 13 days for the Fontan procedure nationally.[18] The risk of death for univentricular patients is highest in the first 5 years but eventually levels off at 15 years. One single-institution study, whose results were published by d'Ukedem et al in 2012, followed 499 patients and finally had 229 patients reach the third stage palliation Fontan procedure at an average age of 5 years old for operation. Survival rates were 82% for the first year, 74% for the 5-year, and 71% for 10-year survival. Results from a recent study demonstrated absent 1- and 2-year mortality and morbidity in patients undergoing Fontan completion at the early adult phase (18 to 21 years). However, a long-term assessment is still missing.[23][24] The postoperative period is an important part of the Fontan procedure. Complications include but are not limited to the following: Hemorrhage Arrhythmias Pleural effusions Hepatic fibrosis Heart failure Chylothorax Cyanosis of the body Exercise intolerance Aortic root dysfunction Ventricular dysfunction Pulmonary vascular dysfunction Protein-losing enteropathy Thromboembolism Kidney disease Liver disease Venous insufficiency Death [2][8][25][26] Although life-saving, physiologic disturbances affect the rest of the body and result in short- and long-term complications.[8] Multiple risk factors have been identified that may contribute to increased mortality, takedown, or transplantation rates.[27] This is a large area of research since complications are consistently related to ultimate mortality.[25] There are mixed results for whether the ventricular side of dominance predisposes patients to a worse outcome; however, some data suggest that patients with right ventricular dominance may predict higher mortality than those with left-sided ventricular dominance.[23][28]

Although life-saving, physiologic disturbances affect the rest of the body and result in short- and long-term complications.[8] Multiple risk factors have been identified that may contribute to increased mortality, takedown, or transplantation rates.[27] This is a large area of research since complications are consistently related to ultimate mortality.[25] There are mixed results for whether the ventricular side of dominance predisposes patients to a worse outcome; however, some data suggest that patients with right ventricular dominance may predict higher mortality than those with left-sided ventricular dominance.[23][28] Systemic complications become challenging to quantify since they occur outside of the heart and affect other organ systems. Research is ongoing to determine lymphatic drainage's role in failed Fontan circulation, which results in multiple comorbidities.[26] Systemic complications such as protein-losing enteropathy (PLE) and plastic bronchitis can occur in up to 5% of all Fontan patients and result in a notably increased risk of mortality of up to 50% after 5 years of diagnosis.[8] Plastic bronchitis is a rare and ominous complication for patients with Fontan circulation, marked by the formation of casts within the tracheobronchial tree. These casts may be cellular, containing inflammatory debris, or acellular, consisting of mucin and fibrin—the latter more commonly linked to congenital heart disease. The proposed mechanism mirrors PLEs, involving protein and lymphatic leakage within the airways. Associations have been noted with diaphragm plication, chylothorax, and seasonal allergies.[29][30] These casts can obstruct the airway and may prove acutely fatal. The condition carries substantial morbidity, as highlighted in the results from a study where, among 671 Fontan respondents, 53 reported plastic bronchitis. Of these, only 9% had no hospitalizations, while 17% experienced more than 10 admissions related to the condition. Treatment focuses on optimizing Fontan hemodynamics and managing the disease’s effects.[31][32]

These casts can obstruct the airway and may prove acutely fatal. The condition carries substantial morbidity, as highlighted in the results from a study where, among 671 Fontan respondents, 53 reported plastic bronchitis. Of these, only 9% had no hospitalizations, while 17% experienced more than 10 admissions related to the condition. Treatment focuses on optimizing Fontan hemodynamics and managing the disease’s effects.[31][32] Crupi first documented PLE in a patient with Fontan with single-ventricle physiology.[33] PLE has been observed not only in Fontan circulation but also in connection with various cardiovascular conditions, including constrictive pericarditis, tricuspid regurgitation, and congenital heart disease. Notably, Moodie et al reported PLE in a patient with transposition of the great arteries and systemic venous obstruction postatrial switch.[34] The unifying feature among these cardiovascular conditions is elevated systemic venous pressure, leading to a hypothesis: heightened venous pressure may cause lymphatic dilation (lymphangiectasis) and protein loss into the gut lumen.[35] However, this theory is insufficient, as systemic venous pressures alone do not consistently correlate with PLE presence or severity. For example, PLE is uncommon following the Glenn procedure, which raises superior vena cava and thoracic duct pressure, and lymphangiectasis is not consistently seen in PLE patients post Fontan procedure. Despite elevated systemic venous pressures across all Fontan patients, not all develop PLE, suggesting additional contributory factors. Results from an international multi-center study conducted by Mertens et al in 1998 revealed a common feature in PLE individuals post Fontan procedure: significantly reduced cardiac output, averaging 2.4 L/min/m², compared to the typical range of 3 to 3.5 L/min/m² in patients with Fontan but without PLE.[36] Those with PLE demonstrated even lower cardiac output indices, around 1.5 to 2.0 L/min/m². This finding implies that PLE may result not solely from elevated venous pressures but from slightly raised venous pressure and markedly reduced cardiac output, which limits intestinal perfusion pressure and end-organ blood flow. Thus, a connection between reduced cardiac output and the development of PLE in patients with Fontan may exist.

Results from an international multi-center study conducted by Mertens et al in 1998 revealed a common feature in PLE individuals post Fontan procedure: significantly reduced cardiac output, averaging 2.4 L/min/m², compared to the typical range of 3 to 3.5 L/min/m² in patients with Fontan but without PLE.[36] Those with PLE demonstrated even lower cardiac output indices, around 1.5 to 2.0 L/min/m². This finding implies that PLE may result not solely from elevated venous pressures but from slightly raised venous pressure and markedly reduced cardiac output, which limits intestinal perfusion pressure and end-organ blood flow. Thus, a connection between reduced cardiac output and the development of PLE in patients with Fontan may exist. Another etiology discovered by Rychik and colleagues in 1991 was the association of PLE with excessively elevated mesenteric arterial pressures.[37] Through Doppler echocardiography, blood flow was assessed at the origin of the superior mesenteric artery. The resistance index—a marker of vascular resistance— was calculated in control subjects with normal circulation, those with Fontan without PLE, and Fontan individuals with active PLE. Distinct variations in resistance indices emerged, with Fontan individuals exhibiting elevated resistance compared to controls, and further increased resistance was observed in those with PLE. Qualitative inspection of Doppler flow patterns revealed a clear trend: as mesenteric vascular resistance rose, diastolic flow velocities fell. Patients with active PLE showed nearly absent diastolic flow, indicating high mesenteric vascular resistance. These findings point to a fundamental connection between the unique physiology of Fontan circulation and altered mesenteric blood flow, offering valuable insight into the pathophysiology of PLE post-Fontan operation. In addition, increased central venous pressure can contribute to liver disease, hepatocellular carcinoma, liver fibrosis, and cirrhosis.[38] Anticoagulants such as warfarin or antiplatelet therapy such as aspirin are used for thromboembolic complications.[39] There is currently no consensus for optimal antithrombotics regimen or duration after the Fontan procedure, but up to 25% of thromboembolic events can result in death.[10]

In addition, increased central venous pressure can contribute to liver disease, hepatocellular carcinoma, liver fibrosis, and cirrhosis.[38] Anticoagulants such as warfarin or antiplatelet therapy such as aspirin are used for thromboembolic complications.[39] There is currently no consensus for optimal antithrombotics regimen or duration after the Fontan procedure, but up to 25% of thromboembolic events can result in death.[10] Ultimately, patients with Fontan circulation will have lower-than-expected exercise tolerance when they reach adolescence. Usually, there is some type of ventricular dysfunction. Long-term results are still being studied since more patients survive into adolescence and early adulthood. Whether there are modifiable risk factors that will prevent this clinical deterioration or not is still uncertain. Still, if a patient is in heart failure after Fontan, they will need to be considered for heart transplantation.[8]  Mechanical circulatory devices have also been described as being used to bridge failing Fontan individuals to transplant.[40] Atz et al, as part of the Pediatric Heart Network, followed about 373 adult patients from an initial cohort of 546 subjects to study the transplant-free survival rates into adulthood. Their results found cardiac reoperation (32%), arrhythmia treatment (32%), thrombosis (12%), and PLE (9%) as the most common complications. About 10% received transplants or succumbed without transplantation.[41]

The successful treatment of patients undergoing the Fontan completion procedure relies on a multidisciplinary team approach that prioritizes patient-centered care, safety, and optimal outcomes. Clinicians and surgeons must coordinate preoperative assessment, surgical planning, and postoperative care, ensuring patients meet the stringent criteria for Fontan completion. Advanced clinicians and nurses play a vital role in preoperative education, facilitating communication between the patient and the healthcare team and providing postoperative monitoring for complications like arrhythmias or thromboembolism. Pharmacists contribute by optimizing anticoagulation protocols and managing medication regimens tailored to individual needs, particularly for patients with complex histories or comorbidities. Interprofessional communication is essential to streamline decision-making and maintain cohesive care throughout the perioperative period. Regular team meetings and standardized protocols can help align goals across disciplines, fostering collaboration. Coordinated care includes meticulous monitoring of hemodynamic parameters, effective management of extracardiac manifestations such as liver dysfunction, and integration of long-term follow-up plans for managing Fontan-associated complications. By leveraging the expertise of each team member and maintaining open communication, healthcare professionals can enhance patient safety, improve outcomes, and support the growing population of Fontan individuals with comprehensive, high-quality care.

Regionalizing databases and interventions is a promising approach to addressing the unique challenges of studying and managing congenital heart disease, particularly for complex procedures like the Fontan. The Southwest Congenital Cardiac Consortium exemplifies this strategy by fostering interprofessional collaboration across institutions to identify and mitigate healthcare disparities. This initiative highlights the potential for regional efforts to improve outcomes and equity for high-risk populations, such as those in the southwest United States.[5] By leveraging shared data and collaborative practices, such consortiums aim to standardize care and address systemic barriers contributing to health inequities. Efforts to enhance post Fontan recovery and long-term health outcomes have also explored targeted rehabilitation interventions. For example, results from a study assessing muscle training in Fontan individuals demonstrated promising improvements in exercise capacity over 12 weeks. While the study showed encouraging results, it was limited by its small sample size, underscoring the need for further research. These findings suggest that structured rehabilitation programs could become integral to post Fontan care, potentially improving functional status and quality of life in this growing patient population.[7]