In my practice, I am asked to give input on patients with Fontan procedure infrequently. A few recent articles though are a good resource:
- Nutr Clin Pract 2012; 27: 375-84
- J Pediatr 2012;161:186-90
Both articles review the physiology and therapies available. In essence, the Fontan operation establishes a passive connection between the systemic venous return and the pulmonary circulation. When there are elevated inferior vena cava pressure, this can lead to hepatic dysfunction and protein-losing enteropathy. The latter is related to engorged intestinal lymphatics, similar to that in congenital intestinal lymphangiectasia. When lymphatic proteins leak, PLE only develops when the intestinal leak exceeds the patient’s ability to resynthesize lost proteins.
PLE presenting features: edema, diarrhea, bloating, pain, and pleural or pericardial effusions. PLE places patient at risk for growth failure and associated problems. In more severe cases, hypocalcemia and infections due to lymphopenia can be present.
- Agents that improve heart function -diuretics, pulmonary vasodilators (eg. sildenafil)
- Corticosteroids including budesonide. While improvement is common, hypoproteinemia returns after weaning of medication. Systemic side effects occur even with budesonide.
- Low molecular weight heparin. Heparin likely helps by acting as a barrier to large molecules by improving the integrity of the basement membrane
- Octreotide -has shown some effectiveness as an adjunct to other therapies in small studies
- Albumin infusions
- Diet: high protein (≥ 2 g/kg/day), low-fat (<25% of calories from fat), increase medium-chain triglycerides, & sodium-reduced
- Surgical treatment (eg. atrial baffle fenestration) and cardiac transplantation
The second reference notes that many centers are delaying the Fontan procedure and accepting some degree of hypoxemia. The problems with this approach include symptoms like headaches and decreased energy levels and the likelihood of developing pulmonary arteriovenous malformations. Ultimately, the authors hypothesize that biomedical engineers may develop better solutions with miniaturized mechanical support devices to improve pulmonary blood flow.
- Ann Thorac Surg 2010; 89: 837-42. Budesonide for Fontan-associated PLE
- Ann Thorac Surg 2011; 92: 1451-56. Budesonide for Fontan-associated PLE
- Congenit Heart Dis 2009; 4: 107-11. Use of sildenafil for failing Fontan.