The Fontan procedure is a repair surgical strategy for congenital cardiac anomalies. It is not usually used in isolation, but in combination with other repair procedures in a staged manner in an attempt to correct the underlying cardiac pathology.
The procedure attempts to bypass the right heart. Systemic circulation is redirected into the pulmonary arteries.
It can be used in multiple situations, including:
- tricuspid atresia
- hypoplastic left heart (part of the overall repair strategy)
- hypoplastic right heart
- other types of single ventricle physiology
The original procedure involved:
- closure of atrial septal defect (ASD) and tricuspid valve
- creation of an anastomosis between the right atrial appendage and the main pulmonary artery
Modified Fontan procedure
In order to improve flow dynamics, the original procedure has been modified and approaches developed which provide superior flow to the pulmonary circulation. The modified procedures involve creating a total cavopulmonary anastomosis, such that systemic venous return from both superior (SVC) and inferior vena cava (IVC) both supply the pulmonary arterial system.
There are two primary approaches: the "lateral tunnel" versus the "extracardiac conduit". In both situations, the SVC is divided at the superior cavoatrial junction and connected to the right pulmonary artery (i.e. bidirectional Glenn shunt). The difference is in the technique used to route IVC blood to the pulmonary artery:
lateral tunnel 7, 8
- a patent connection at the superior cavoatrial junction is established between the right atrium and the inferior aspect of the right pulmonary artery
- through an atriotomy, a synthetic or pericardial baffle is placed, which effectively bisects the right atrium, creating a passageway laterally for caval blood to reach the right pulmonary artery while leaving a more "normal" neo-atrium medially
- a sharp instrument is frequently used to create a 4-5 mm fenestration in the baffle, in order to allow some degree of pulmonary-to-systemic (right-to-left) shunting
- no atrial-pulmonary connection is established
- IVC is divided at the inferior cavoatrial junction, and the defect at the inferior right atrium is closed
- a synthetic conduit is used to connect the transected IVC to the inferior aspect of the right pulmonary artery. The conduit courses adjacent to the right atrium
- a small connection between the conduit and the right atrium may be created, serving the same purpose as a fenestration (right-to-left shunt)
The intent of both of these procedures is to provide superior systemic-to-pulmonary flow while maintaining as much normal right atrium as possible in order to avoid arrhythmia.
The merits of each approach remain under study. In general, the extracardiac conduit results in less manipulation of the right atrium but is prone to conduit-complications.
Treatment and prognosis
Although a palliative procedure, patients treated with the Fontan procedure can reach adulthood. The maximum duration of the procedure is not well-defined.
A patient with a failing Fontan repair can receive an extracardiac Fontan conduit if they do not already have one. The definitive procedure is cardiac transplantation.
Intracardiac and central venous thromboses are major causes of morbidity and mortality in patients after the Fontan procedure. This can occur in 1%-33% 4. Patients with a fenestrated baffle or conduit are frequently maintained on pharmacologic anticoagulation in order to reduce the risk of stroke from paradoxical emboli 8.
History and etymology
The procedure was originally suggested in 1971 by F Fontan and E Baudet as a correction for tricuspid atresia.
- 1. Fontan F, Baudet E. Surgical repair of tricuspid atresia. Thorax. 1971;26 (3): 240-8. Free text at pubmed - Pubmed citation
- 2. d'Udekem Y, Iyengar AJ, Cochrane AD et-al. The Fontan procedure: contemporary techniques have improved long-term outcomes. Circulation. 2007;116 (11_suppl): I157-64. doi:10.1161/CIRCULATIONAHA.106.676445 - Pubmed citation
- 3. Fuster V, Walsh R, Harrington R. Hurst's the heart. McGraw-Hill Professional. ISBN:0071636463. Read it at Google Books - Find it at Amazon
- 4. Ghadimi Mahani M, Agarwal PP, Rigsby CK et-al. CT for Assessment of Thrombosis and Pulmonary Embolism in Multiple Stages of Single-Ventricle Palliation: Challenges and Suggested Protocols. Radiographics. 2016;36 (5): 1273-84. doi:10.1148/rg.2016150233 - Pubmed citation
- 5. Fredenburg TB, Johnson TR, Cohen MD. The Fontan procedure: anatomy, complications, and manifestations of failure. Radiographics : a review publication of the Radiological Society of North America, Inc. 31 (2): 453-63. doi:10.1148/rg.312105027 - Pubmed
- 6. Deal BJ, Jacobs ML. Management of the failing Fontan circulation. Heart (British Cardiac Society). 98 (14): 1098-104. doi:10.1136/heartjnl-2011-301133 - Pubmed
- 7. van Doorn CA, de Leval MR. The Lateral Tunnel Fontan. (2006) Operative Techniques in Thoracic and Cardiovascular Surgery. 11 (2):105-122. doi:10.1053/j.optechstcvs.2006.05.001
- 8. Brown JW, Ruzmetov M, Deschner BW, Rodefeld MD, Turrentine MW. Lateral tunnel Fontan in the current era: is it still a good option?. (2010) The Annals of thoracic surgery. 89 (2): 556-62; discussion 562-3. doi:10.1016/j.athoracsur.2009.10.050 - Pubmed
- 9. Han BK, Lesser JR. CT imaging in congenital heart disease: an approach to imaging and interpreting complex lesions after surgical intervention for tetralogy of Fallot, transposition of the great arteries, and single ventricle heart disease. (2013) Journal of cardiovascular computed tomography. 7 (6): 338-53. doi:10.1016/j.jcct.2013.10.003 - Pubmed
Related Radiopaedia articles
Congenital heart disease
There is more than one way to present the variety of congenital heart diseases. Whichever way they are categorized, it is helpful to have a working understanding of normal and fetal circulation, as well as an understanding of the segmental approach to imaging in congenital heart disease.
congenital heart disease
- normal relationship between chambers and valves
- atrioventricular valves
- outflow tract
- great vessels
- venous inflow
- anomalous valves
- abnormal relationship of chambers and valves
- atrioventricular abnormality
- great vessel connection abnormality
- conotruncal cardiac anomalies
- pentalogy of Cantrell
- Shone syndrome
- congenital heart disease - chest x-ray approach
surgical repairs (mnemonic)
- arterial switch procedure
- Blalock-Taussig shunt
- double switch procedure
- Fontan procedure
- Glenn procedure
- Mustard repair
- Norwood procedure
- Pott shunt
- pulmonary artery banding
- Rastelli procedure
- Sano shunt
- Senning repair
- total repair of tetralogy of Fallot (TOF)
- unifocalisation procedure
- Waterston shunt