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CHAPTER SUMMARY AND CENTRAL ILLUSTRATION
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Chapter Summary
This chapter describes management of the single ventricle post-Fontan palliation. The Fontan procedure has been used to palliate a broad spectrum of univentricular physiologies when biventricular repair is not feasible. Although Fontan physiology represents a hemodynamic compromise between systemic venous hypertension and pulmonary hypotension, it is generally considered successful if venous congestion is mild, along with the reduction in cardiac output. Failing Fontan is characterized by marked venous congestion and low cardiac output with multiorgan manifestations. A relatively uneventful clinical course during the first 10 to 15 years after Fontan surgery may be followed by the onset of complications such as arrhythmias, heart failure, increased pulmonary vascular resistance, protein losing enteropathy, thromboembolism, and liver disease (see Fuster and Hurst’s Central Illustration). As a result of considerable morbidity in adulthood, regular screening and surveillance with laboratory tests, imaging studies, arrhythmia monitoring, and objective assessment of functional capacity is required by caregivers with expertise in congenital heart disease. The threshold for cardiac catheterization should generally be low in the setting of new-onset or progressive symptoms. Therapeutic management is dictated by the type of complication encountered. In patients refractory to medical therapy and/or percutaneous interventions, surgical options (including Fontan conversion and transplantation) should be discussed by a multidisciplinary team.
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History and Epidemiology
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The univentricular heart is a rare and complex form of congenital heart disease, with an overall prevalence of approximately 2 per 10,000 live births. The single functional ventricle could be morphologically right (RV) or left (LV), with the second ventricle usually hypoplastic and/or insufficiently functional for a biventricular correction. The different subtypes of univentricular heart include those associated with an absent or atretic atrioventricular (AV) valve (eg, tricuspid atresia, hypoplastic RV in the setting of pulmonary atresia, and hypoplastic left heart syndrome [HLHS]), a common AV valve with only one well-developed ventricle, and heterotaxy syndromes (ie, disorders of lateralization).
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Fontan palliation was first introduced by Drs. Francis Fontan and Eugène Beaudet in Bordeaux (France) in 1968. In 1971, they reported three patients with tricuspid atresia palliated by a Fontan procedure, two of whom survived.1 The Fontan procedure expanded on the work by Dr. William Glenn from Yale University, first described in 1954 and then in 1958, consisting of a cavopulmonary anastomosis of the superior vena cava to the right pulmonary artery. This approach had been used to palliate a broad spectrum of univentricular physiologies, when biventricular repair was not possible. By 2018, it was estimated that 50,000 to 80,000 patients across the world lived with a Fontan procedure.2 Importantly, the Fontan procedure is likewise palliative because the surgery maintains a univentricular system with no ventricular pump ...