Fontan Operation Overview: ACHD, congenital heart disease, heart surgery, single ventricle, separate oxygen-rich and oxygen-poor blood

Fontan Operation - What it is

The Fontan operation is the last stage of a series of operations to create a pathway for poor-oxygen blood to bypass one of the ventricles and drain directly into the lungs. This procedure is usually performed on patients who only have one effective ventricle to pump blood to both the body and lungs.

In a healthy heart, the left side of the heart pumps oxygen-rich blood to the rest of the body while the right side pumps oxygen-poor blood to the lungs.

The normal heart has 4 pumping chambers, the left and right atria (upper chambers) and the left and right ventricles (lower chambers). The right ventricle pumps oxygen-poor blood to the lungs while the left ventricle pumps oxygen-rich blood to the body. However, babies with certain complex congenital heart conditions are born with only one functional ventricle while the other one is usually underdeveloped and may exist with a non-functional valve. Since only one ventricle is pumping normally, both oxygen-rich and oxygen-poor blood get mixed in this chamber. As such, the blood that is pumped to the rest of the body has much lower oxygen levels than normal.

The aim of the Fontan operation is thus to separate the oxygen-poor blood from the oxygen-rich blood. Oxygen-poor blood is directed to the blood vessels leading to the lungs, which allows the single ventricle to only pump oxygen-rich blood to the body. This procedure should increase the blood flow into lungs, reduce the workload of the single ventricle and improve exercise tolerance of patients.

In most patients with complex congenital heart diseases, the Fontan operation is usually performed during childhood. However, it is possible to find un-operated adults who are suitable for the Fontan operation later on in life. These patients will need careful assessment of their heart and blood circulation before surgery. Most patients will be well for many years after the Fontan operation though there are some patients who may develop complications, especially those who completed the procedure at a later age.