Late Consequences of the Fontan Operation

A 15-year-old boy with hypoplastic left heart syndrome presents with new-onset abdominal swelling and pretibial edema. The patient has been previously without symptoms from the cardiovascular perspective but is not very active and does not participate in sports. He is growing poorly, with height and weight <5th percentile for age, and has no signs of puberty (Tanner stage 1). Blood laboratories reveal low serum protein (albumin, 2.2 g/dL; total protein, 4.5 g/dL); liver enzymes are slightly elevated (aspartate aminotransferase, 60; alanine transaminase, 72); platelet count is diminished at 105 000/dL. Stool sample is tested for α1-antitrypsin, which is markedly elevated (382 mg/dL), indicating protein-losing enteropathy (PLE). Abdominal ultrasound demonstrates ascites and an enlarged, heterogeneously echogenic liver. Echocardiography demonstrates unobstructed systemic and pulmonary venous pathways, good right ventricular function, mild tricuspid regurgitation, and unobstructed aortic arch. Cardiac catheterization shows pulmonary artery pressure of 12 mm Hg and right ventricle end diastolic pressure of 6 mm Hg. Gastrointestinal endoscopy with biopsy is recommended, which reveals small-bowel lymphangiectasia and inflammation localized to the terminal ileum.Patients born with a univentricular heart manifest one of the most challenging-to-manage forms of congenital heart disease. Over the past 30 years, a successful staged surgical strategy has emerged. The task of systemic perfusion is assigned to the one effective ventricle that nature has provided, whereas pulmonary blood flow is achieved through passive channeling of systemic venous return directly to the pulmonary arteries, absent an interposed ventricle.1 Today, this is typically achieved in a 2-stage process. Superior vena caval flow is directed into the branch pulmonary arteries (bidirectional Glenn operation) at 4 to 6 months of age, and inferior vena caval flow is diverted directly to the pulmonary arteries (Fontan operation), either via a tunnel through the atrium or an extracardiac conduit, at 2 to 3 years …