The Fontan is an open-heart surgery used to treat a variety of cardiac defects that are present at birth (congenital heart defects). It is commonly used on children who have been born with either no separation between the right and left ventricles of the heart (a ventricular septal defect), with only one functional ventricle or the lack of development of one or more heart valves. The common factor is that the patient has only one functioning ventricle or, because of the nature of the defect, the patient is best served by being left with only one functioning ventricle.

During this operation, surgeons create a passageway that allows blood to bypass the right ventricle, which is usually responsible for pumping oxygen–poor blood to the lungs for fresh oxygen. By routing blood around the right ventricle, surgeons are able to adapt the right ventricle to pump oxygen-rich blood to the body if the left ventricle is unable to. In other cases in which the left ventricle is healthy, but the right ventricle is too small to pump blood or is totally missing, the Fontan procedure may be performed simply to bypass circulation around the under-performing right ventricle.

There are two stages to the Fontan, which are usually performed at two different times in a young patient’s life to allow the body to adjust to the new blood flow. Each stage requires between several days and about three weeks of recovery time in the hospital.

Although the Fontan is often lifesaving, it also carries a number of risks. Family members are encouraged to discuss all the risks and benefits of the procedure with their pediatric cardiologist.

The Fontan is an open-heart surgery used to treat a number of congenital heart defects (conditions that are present at birth). It is typically used on children who have complex cardiac defects in which the heart has only one working chamber (ventricle) or has no wall separating the right and left ventricles.

In a normal heart, oxygen-poor (blue) blood flows into the right atrium (upper chamber) from large veins. Then the blood flows through the tricuspid valve and into the right ventricle. From there, the pulmonary arteries carry the blood into the lungs, where it receives oxygen. Once it has been oxygenated, the blood is carried back to the left side of the heart through the pulmonary veins. It first empties into the left atrium, then travels through the mitral valve into the left ventricle. Finally, the left ventricle pumps the oxygen-rich blood through the aortic valve into the aorta and out to the body.

If, however, a child is born with only one operating ventricle, or with a defect that prevents the normal flow of blood through the heart, physicians may choose to perform a Fontan procedure.

 During this operation, surgeons create a passageway that allows oxygen-poor blood from the body to bypass the heart and go directly to the pulmonary arteries. By routing blood around the heart, surgeons are able to adapt the right ventricle to pump oxygen-rich blood to the body in the event the left ventricle is unable to. In this way, the right ventricle is no longer used to pump blood to the lungs. Instead, the circulation to the lungs is considered passive.

The same principle applies if the left ventricle is healthy and the right ventricle is inadequate.  The basic process is that the oxygen-poor blood is delivered to the pulmonary artery circuit without going through the heart. The oxygen-rich blood returns to the heart to be delivered to the body with only a small amount of oxygen-poor blood in the mixture.

The Fontan procedure was first performed in 1968 by Dr. Francis Fontan to treat tricuspid atresia. Currently, it is performed worldwide to treat a variety of congenital heart defects, including:

The Fontan is also performed as part of the Norwood procedure, which is used to treat hypoplastic left heart syndrome.

Typically, the Fontan procedure is part of a series of surgeries meant to gradually reroute the flow of blood through the heart while also maintaining healthy circulation. These procedures are usually performed over the course of years or months, allowing the child to recover between operations. Other operations that are performed as part of the operations associated with a Fontan procedure include:

• Bi-directional Glenn procedure
  
• Glenn shunt operation (or modified Glenn shunt operation)
  
• Glenn anastomosis
  
• Hemi-Fontan procedure

In a Glenn shunt operation or its modifications, the superior vena cava (which collects oxygen-poor blood from the upper part of the body) is connected directly to the pulmonary artery (which travels from the right ventricle to the lungs).

This new pathway allows oxygen-poor blood from the head and upper body to flow directly to the lungs, bypassing the heart. At this point, the baby will be better able to handle infection and other problems. However, the treatment is only half-finished because the oxygen-poor blood returning from the lower part of the body has not yet been rerouted

The second stage of the Fontan is usually done when the patient is between two and three years old. During this stage, the inferior vena cava (which collects oxygen-poor blood from the lower part of the body) is connected directly to the pulmonary artery. Once both stages of the surgery are complete, oxygen-poor blood from both the upper and lower parts of the body can travel to the lungs for fresh oxygen.

As with most complex congenital heart surgeries, there are a number of variations that might arise in particular circumstances. A fenestrated Fontan procedure is one in which surgeons have created a tiny hole in the conduit that carries blood to the pulmonary arteries as it travels through the right atrium. This hole acts as an "escape valve" if the blood pressure rises too high. In some cases, this hole will be closed later, in a catheter laboratory. In other cases, the hole will close naturally. Fenestrated Fontan procedures are used among children who may have elevated blood pressure in the lungs and who previously had higher rates of complications with a regular Fontan procedure. Besides the fenestrated Fontan, there are other variations of this technique, depending on the unique condition of each patient and the surgeon's preference.

A number of tests may be ordered for the young patient to assess for all heart defects present. These tests include:

In some patients, a physician may need to do a more invasive test called a cardiac catheterization to evaluate the function of the heart, perform imaging studies (angiography), and make some measurements that may not be possible with echocardiography. These are commonly performed between the stages of the Fontan procedure.

The patient is generally admitted to the hospital on the same day as the scheduled surgery. A chest x-ray, EKG and blood tests will again be performed, and the patient will be prepped for surgery. The patient is then given a sleep-inducing medication (general anesthesia) through an intravenous (IV.) line. The patient will continue to breathe a mixture of oxygen and anesthetic gas to make sure that he or she remains asleep throughout the entire surgery.

A breathing tube (endotracheal tube) will first be inserted into the mouth and down the windpipe (trachea) to maintain an airway. A urinary catheter is also inserted and connected to a collection bag to measure the patient’s urine output.

An incision is made in the chest and the breastbone (full median sternotomy). A retractor is then used to gently spread the edges and open up the chest. The child is connected to a heart-lung machine, which allows the heart to be safely stopped during the procedure. Once the heart has been stopped and emptied, the oxygen-poor blood flow is diverted to the pulmonary artery. This may be done by constructing a tunnel within the upper ventricle or by grafting a tube outside of the chamber. In some patients, a small window (fenestration) is used allow the blood to mix and to help balance the pressure. Some temporary drains will be placed in the child as well. 

After the procedure has been completed, the heart incision is closed and the heart is restarted. When the surgical team is satisfied that the heart is beating strongly again, the heart-lung machine is disconnected. The chest incision is then closed (sutured).

After surgery, the patient is placed in a cardiac surgical intensive care unit. The child initially will be on a breathing machine (ventilator) and will be connected to several machines. Heart rate, blood pressure, respiratory rate, the oxygen level in the blood, and several other parameters are continuously monitored in the patient while the patient is in the intensive care unit.

Family will be able to visit periodically. Medications that regulate circulation and blood pressure may be administered through the IV (intravenously). A breathing tube (endotracheal tube) will remain in place until the physicians are confident that the patient is awake and ready to breathe comfortably on his or her own.

The patient may be groggy and somewhat disoriented, and sites of incisions in the chest may be sore. Painkillers may be administered. There may be bleeding from within the chest for two to five days following surgery. To control this, a drainage tube may be placed in the sack around the heart that leads out through the skin.

Patients usually stay in the hospital for several days to three weeks. During this time, more tests will be conducted to assess and monitor the patient’s condition. The cardiologist and surgeon will discuss further medical treatment, including the use of pain medications and/or anticoagulants. Any medications the child has been taking may also be updated.

Some patients may be given aspirin or warfarin to reduce the risk of a blood vessel clotting after the procedure. Prior to discharge from the hospital, the family is given specific instructions regarding care of the incision site, activity restrictions and recovery expectations. Information is also provided about signs or symptoms that indicated the need for medial attention. The surgeon and/or cardiologist typically see children for a follow-up visit two to three weeks after discharge from the hospital.

In general, children who have undergone the Fontan procedure will need lifelong follow-up with a cardiologist who is familiar with congenital heart conditions.

The Fontan procedure’s main benefit is to infants with serious congenital heart defects that reduce the amount of oxygen-rich blood being pumped to the body. In these cases, the Fontan allows surgeons to bypass the right side of the heart and send oxygen-poor blood directly to the lungs. The right ventricle may then be pressed into service as the heart’s main pumping chamber, sending oxygen-rich blood to the tissues and organs of the body. The procedure is also valuable in patients whose right side of the heart is malfunctioning for some reason, whether or not the left ventricle is involved.

In general, the Fontan is less risky for patients who have fewer heart defects. Ideally, the patient has a normal pulmonary artery, normal drainage of oxygen-poor blood from the veins into the heart, normal pumping ability of the ventricles, normal heart rhythm, a normal-sized right atrium and so forth. The surgeon needs to know as much as possible about other heart defects that may be present before surgery begins.

However, even under ideal circumstances, the Fontan is complicated and carries a number of risks to the young patient. These risks include:

• Formation of blood clots. Because the surgery currently involves the use of foreign materials to create new passageways, there is a risk of blood clots forming in and around those foreign materials. To reduce the risk of blood clots, patients are generally prescribed daily aspirin and/or anticoagulants for months after surgery and often continue taking aspirin for life. Researchers are developing strategies for performing the Fontan without using foreign materials.

There are a number of variants of the standard Fontan. They include the following:

There are also a number of variations in which the right ventricle contributes some pumping ability to the passage of blood from the venae cavae to the lungs. Researchers continue to work on developing the safest, most effective procedure possible.

Preparing questions in advance can help patients to have more meaningful discussions with their physicians regarding their conditions. Parents may wish to ask their children’s doctors the following questions related to the Fontan procedure:

1. What type of heart defect does my child have?
   
   
2. What problems will this heart defect cause?
   
   
3. How will the Fontan procedure correct this defect?
   
   
4. Are there any alternate surgeries or medications my child could take in place of the Fontan?
   
   
5. Will the procedure be performed in one or multiple surgeries?
   
   
6. How soon does my child need the surgery?
   
   
7. When will the additional surgeries be performed, if necessary?
   
   
8. Which variation of the Fontan do you plan to perform on my child?
   
   
9. What are the risks associated with this surgery?
   
   
10. What can I expect in terms of my child’s recovery?
    
    
11. What restrictions will my child have following surgery?
    
    
12. How will this defect and procedure affect my child’s life?
    
    
13. How will the condition be monitored through life?
    
    
14. If I have another child, what are the chances of a similar heart defect?
    
    
15. Can you recommend me to an appropriate support group?
    
    
16. Are there services available that may help with the financial obligations that are anticipated?
    
    
17. How will this impact my child’s growth and development?
    
    
18. Is this heart condition associated with any genetic conditions that may be of concern?