Background

With improved survival of patients with single-ventricle (SV) congenital heart disease (CHD), there is a growing population of patients with Fontan circulation. These patients present unique challenges in their medical evaluation and management. There are several ongoing investigations targeting optimization of care, including routine surveillance, diagnostic studies, and potential treatment options.¹ Many centers have developed specialized multidisciplinary clinics dedicated to patients with Fontan circulation to ensure that health care needs are addressed from childhood into adulthood.² Recently, a lifespan learning network, the Fontan Outcomes Network (FON), has also been created to evaluate current metrics and improve outcomes in this unique patient population. The effects of the Fontan circulation extend well beyond the heart and vasculature to many other organ systems. Consequently, in addition to cardiac management, surveillance of noncardiac function and comorbidities is a core part of Fontan care. Although helpful resources to guide practice exist, the optimal frequency of follow-up and testing in patients with Fontan circulation is not exactly known, leading to a wide variation in clinical practice and resource utilization.

Goals and Details of the Algorithm

The goal of the Clinical Practice Algorithm for the Follow-Up of Patients With Fontan Circulation is to offer clinicians a suggested decision support tool based on current evidence that may be used in patients with Fontan circulation, beginning in the early post-Fontan period and into adulthood. This tool can help clinicians and centers adopt a standard approach for frequency of follow-up and diagnostic testing. Cardiologists and health care providers may use the algorithm as a reference point in the management of these patients. However, it is not intended to replace medical decision-making on more complex cases, especially involving extracardiac comorbidities. Individualized patient care is essential and encouraged. Notably, the algorithm is meant to be a dynamic, changing document that will be updated over time with the emergence of new evidence on best practices as clinical understanding of Fontan circulation evolves.

The Fontan algorithm includes subalgorithms by age-group (Fontan <12 Years of Age, Fontan 12-18 Years of Age, and Fontan ≥18 Years of Age). The <12 Years of Age algorithm begins with the initial standard surgical follow-up evaluation and progresses to follow-up frequency and surveillance testing at regular time intervals. The 12-18 Years of Age algorithm provides follow-up frequency and surveillance testing by time intervals, with some modalities increasing in frequency in preparation for transition to adult CHD care. Patients with Fontan circulation deemed clinically stable are those without hemodynamically significant heart failure, protein-losing enteropathy, plastic bronchitis, recent acute events, or hospitalizations over the prior 12 months (>1 year after Fontan completion). Clinic visits include the standard cardiopulmonary physical examination, with attention to hepatosplenomegaly, venous congestion, and peripheral edema. Evaluation and surveillance recommendations are meant to identify possible complications that may develop in this unique patient population, including circulatory failure, ventricular dysfunction, cyanosis, atrioventricular valve regurgitation, arrhythmias, protein-losing enteropathy, plastic bronchitis, liver fibrosis and cirrhosis, renal dysfunction, somatic growth/bone health/physical developmental issues, psychosocial challenges, and neurocognitive dysfunction. In-depth testing and subspecialty consultation tailored to the organ system involved is recommended.¹ Frequency of echocardiography is guided by the Appropriate Use Criteria for Multimodality Imaging During the Follow-Up Care of Patients With Congenital Heart Disease.³ An arm for therapies is included to provide a list of commonly used medications.^1,4,5 Note that this list is by no means comprehensive. Thromboprophylaxis,^1,5 lifestyle counseling including exercise,^1,2 and identification of psychosocial needs¹ are also essential considerations in this high-risk population.

The adult Fontan algorithm has been designed as general guidance to assist in the management of relatively healthy patients with uncomplicated Fontan circulation. Adult CHD clinicians will need to establish strong foundational relationships with these patients who may be accustomed to a different approach to care provided at pediatric centers. Continued care at pediatric centers carries its own challenges, including availability of adult subspecialty care and expertise. Therefore, local and regional contexts will be integral in consideration of the best manner to implement the algorithms and transition from pediatric to adult care. Suggested time intervals for screening for Fontan complications, including development of collateral vessels, Fontan circulatory failure, liver disease, protein losing enteropathy, and plastic bronchitis, are provided.^1,6-8 Preventative and proactive management is recommended, including thrombosis prophylaxis,⁵ routine vaccinations, lifestyle counseling,⁸ and appropriate referrals for psychosocial intervention and advanced heart failure management.⁹ Commonly used medications are listed in the algorithm, although it is acknowledged that studies in the SV population are limited.^4,8,10

Methods: Algorithm Development

The algorithm was created by the Quality Working Group of the American College of Cardiology (ACC) Adult Congenital and Pediatric Cardiology (ACPC) member section. This is a multidisciplinary group of experienced pediatric and adult congenital cardiologists from diverse training and practice backgrounds. Subsets of this group successfully derived a series of algorithms for mildly complex CHD, the first of which was for secundum atrial septal defect. The same quality-driven approach was used for the development of this Fontan algorithm to translate current evidence into best practice recommendations. Fontan-specific references and existing guidelines were used to create the evidence-based algorithm. The Fontan algorithm was then peer reviewed for consensus, including by FON leadership, to ensure alignment with their clinical recommendations.

Conclusion

The Fontan algorithm can be integrated into clinical practice as a decision support tool for clinicians providing care for patients with Fontan circulation. Centers may implement related quality improvement initiatives and projects that may be used for Maintenance of Certification (MOC) part IV credit. The widespread use and implementation of the Fontan clinical practice algorithm has the potential to improve resource utilization and standardize the care of patients with Fontan circulation.

References

1. Rychik J, Atz AM, Celermajer DS, et al.; American Heart Association Council on Cardiovascular Disease in the Young and Council on Cardiovascular and Stroke Nursing. Evaluation and management of the child and adult with Fontan circulation: a scientific statement from the American Heart Association. Circulation 2019;140:e234-e284.
2. Rychik J, Goldberg DJ, Rand E, et al. A path FORWARD: development of a comprehensive multidisciplinary clinic to create health and wellness for the child and adolescent with a Fontan circulation. Pediatr Cardiol 2022;43:1175-92.
3. Sachdeva R, Valente AM, Armstrong AK, et al. ACC/AHA/ASE/HRS/ISACHD/SCAI/SCCT/SCMR/SOPE 2020 appropriate use criteria for multimodality imaging during the follow-up care of patients with congenital heart disease: a report of the American College of Cardiology Solution Set Oversight Committee and Appropriate Use Criteria Task Force, American Heart Association, American Society of Echocardiography, Heart Rhythm Society, International Society for Adult Congenital Heart Disease, Society for Cardiovascular Angiography and Interventions, Society of Cardiovascular Computed Tomography, Society for Cardiovascular Magnetic Resonance, and Society of Pediatric Echocardiography. J Am Coll Cardiol 2020;75:657-703.
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5. Van den Eynde J, Possner M, Alahdab F, et al. Thromboprophylaxis in patients with Fontan circulation. J Am Coll Cardiol 2023;81:374-89.
6. Di Maria MV, Brown DW, Cetta F, et al. Surveillance testing and preventive care after Fontan operation: a multi-institutional survey. Pediatr Cardiol 2019;40:110-5.
7. Emamaullee J, Zaidi AN, Schiano T, et al. Fontan-associated liver disease: screening, management, and transplant considerations. Circulation 2020;142:591-604.
8. Stout KK, Daniels CJ, Aboulhosn JA, et al. 2018 AHA/ACC guideline for the management of adults with congenital heart disease: a report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. J Am Coll Cardiol 2019;73:e81-e192.
9. Lubert AM, Cedars A, Almond CS, et al. Considerations for advanced heart failure consultation in individuals with Fontan circulation: recommendations from ACTION. Circ Heart Fail 2023;16:[ePub ahead of print].
10. Konduri A, West C, Lowery R, et al. Experience with SGLT2 inhibitors in patients with single ventricle congenital heart disease and Fontan circulatory failure. Pediatr Cardiol 2023;46:81-8.