Fontan Procedure is an open heart surgery where a passageway is created to shunt the nonoxygenated blood directly to the pulmonary artery and lungs bypassing the right ventricle. Dr. Francis Fontan first performed this operation in 1968. In 1971, Dr. Fontan and Dr. Kreutzer initially described this procedure as a surgical management for tricuspid atresia.
This operation is an open heart procedure used to treat or manage complex heart defects such as:
- Tricuspid Atresia – a congenital heart defect where the tricuspid valve (valve that is located in between the right atrium and right ventricle) is closed thus preventing blood from entering the pulmonary artery and lungs.
- Hypoplastic left heart syndrome
- Single ventricle
- Pulmonary atresia
Goals of Fontan Procedure
- To improve the oxygenated blood level (by redirecting non-oxygenated blood directly to the lungs)
- To decrease the workload of the heart
- To retain growth potential of the child
Requirements of the procedure
- Normal pulmonary vascular resistance
- Healthy left ventricle to pump the blood in the systemic circulation (Good systolic and diastolic function of left ventricle)
- No valve leak
- Closed atrial septal defect if present
- Normal mitral valve function
Blood goes back to the heart via the superior and inferior vena cava. From these veins, blood empties in the right atrium. Normally, the tricuspid valve opens to drain the blood to the right ventricle. In cases where the tricuspid valve is absent or closed (tricuspid atresia), blood is stuck in the right atrium preventing the blood to enter the right ventricle to be pumped into the pulmonary arteries and lungs. No blood oxygenation would take place.
In a Fontan circulation, a passageway is created from the veins to the pulmonary artery directly. This bypasses the right ventricle of the heart.
Laboratory Tests before the Procedure
Stages of Fontan Procedure
- Blalock-Taussig Shunt
Neonates have increased pulmonary resistance; hence, fontan operation cannot be performed (see procedure requirements). For these cases, a Blalock-Taussig shunt procedure is done as the first operation. A tube graft connects one of the subclavian arteries to the pulmonary artery to ensure pulmonary blood flow and adequate oxygenation for a few months.
- Bi-directional Glenn or Hemi-Fontan procedure
After a few months, when the infant outgrow the shunt, a bidirectional Glenn or hemi-fontan procedure is done. In this procedure, the superior vena cava (SVC) is anastomosed to the pulmonary artery resulting to blood flow from the SVC directly to the pulmonary artery. The Blalock Taussig shunt is removed or ligated. Usually, the operation is done in about 4-8 months of life.
In this procedure, the superior and inferior vena cava are connected to the pulmonary artery.
Several cases have been reported of having good results in children as young as 1 year old. However, most patients are about 18-24 months old when this operation is performed.
Types of Fontan Operation
- Atriopulmonary Connection (original and now rarely used)
In this operation, the right atrium is connected to the pulmonary artery. If atrial septal defect is present, it should be closed. Blood flows from the superior vena cava to the right atrium to the pulmonary artery and lungs.
- Intracardiac total cavopulmonary connection (lateral tunnel)
A tunnel-like patch is placed inside the atrium that directs venous return to the pulmonary artery and into the lungs.
- Extracardiac total cavopulmonary connection
The superior vena cava is directly connected to the pulmonary artery and the inferior vena cava (IVC) is re-routed through a synthetic tube sewn directly to the top of IVC. The tube is connected to the pulmonary artery allowing the non-oxygenated blood to enter the lungs.
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