Clinical Management of Fontan Circulation in children and adults: AHA Scientific Statement
The American Heart Association (AHA) has released a scientific statement on clinical management of Fontan Circulation in children and adults. The statement appeared in Circulation, a journal published by AHA.
The first Fontan palliative surgical procedure was performed in 1968 to treat congenital heart disease (CHD) with tricuspid atresia. Since then, this procedure evolved as an important surgery offering therapy for a range of CHDs including underdeveloped or absent right or left ventricles.
What makes this statement of keen importance is the rise in the number of individuals who survive this condition but the comparative scarcity of medical knowledge of the pathological origin and appropriate care for their distinctive condition affect their management. The worldwide population of patients with Fontan circulation grew to an estimated 50000 to 70000 patients in 2018, with 40% of patients >18 years of age. The current estimate of 30-year survival after surgical Fontan completion is ≈85%. Potential complications involve not only the heart but also multiple organ systems, including the liver, lungs, brain, bones, and lymphatic system.
The end-organ consequences of the Fontan circulation are ubiquitous and usually progressive. Appropriate medical care for these patients requires coordinated input from pediatric and adult congenital cardiologists, as well as multiple subspecialists, many of whom are not familiar with the physiology or the end-organ consequences of the Fontan circulation.
The AHA statement outlines the fundamental cardiovascular and extracardiac physiological challenges faced by the patient with Fontan circulation, defines the current understanding of the end-organ consequences, highlights knowledge gaps in need of further investigational research, and provides a rationale to support diagnostic and therapeutic best practices that will benefit this population as it continues to increase in number and age over the coming years.
- Up to 70 000 patients may be alive worldwide today with Fontan circulation, and this population is expected to double in the next 20 years.
- The Fontan operation is part of the current strategy of care for single ventricle type of congenital heart disease, which creates a unique circulation characterized by a state of chronically elevated central venous pressure and relatively diminished cardiac output.
- Disease exposes these patients to a variety of complications. As more patients grow into and adulthood, it is increasingly evident that these manifestations are poorly understood, and effective treatment strategies are lacking.
- Liver disease is likely present in all patients with a Fontan circulation with variable degrees of hepatomegaly, hepatic congestion, and liver fibrosis common. Elevations of liver function biomarkers are typical, however hepatic functional capacities remain satisfactory in most.
- Cardiovascular complications include the development of ventricular dysfunction, atrioventricular valve regurgitation or arrhythmia.
- Chronic venous congestion leads to lymphatic congestion in all patients with a Fontan circulation, and in some, to potentially life-threatening conditions such as protein-losing enteropathy and plastic bronchitis.
- Renal dysfunction is present in at least 10% of younger patients with a Fontan circulation and increases with age. Impaired renal function may often go unnoticed and should be evaluated in the older patient.
- Patients with Fontan circulation can manifest growth and maturational challenges, including decreased vitamin D, increased parathyroid hormone, low lean muscle mass, and decreased cortical bone mineral density.
- Neurodevelopmental disabilities are common in those with a Fontan circulation. Disorders of mood, anxiety and other mental health and behavioral challenges are highly prevalent, influencing the quality of life.
- Given the relatively high prevalence and possible progressive nature of end-organ dysfunction, an expert consensus opinion-based "toolkit" for surveillance testing for cardiovascular and end-organ complications in the child and adult with a Fontan circulation is proposed in this AHA statement.
- Reduced exercise tolerance is common. Although, healthcare provider restriction to exercise should be rare and exercise training, especially specific strategies such as leg muscle resistance training, may improve cardiac output as well as the quality of life.
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