Researchers (Medical Interests)
For a more detailed look into the operative steps of this surgery please visit this article where Drs. Pelletier and Jacobs have given a series of drawings illustrating the technique for these Fontan and Glenn Stage II operations for patients with a single ventricle. Or visit their informative Modified Fontan article.
Fontan Procedure Summary
The Fontan is an open-heart surgery in which a passageway is created for oxygen-poor blood to bypass the right ventricle and travel directly to the lungs for fresh oxygen. It is used to treat a variety of different congenital heart defects. There are two stages to the Fontan, which are usually performed at two different stages in a young patient’s life. Each stage will require about ten days to three weeks of recovery time in the hospital.
Francis Fontan performed the Fontan operation first in 1968. The Fontan operation is a heart operation used to treat complex congenital heart defects (birth defects of the heart) like tricuspid atresia, hypoplastic left heart syndrome (HLHS), pulmonary atresia and single ventricle.
The aims of the "ideal" Fontan operation are
To achieve a smooth stream-lined blood flow from veins to the lungs
To retain growth potential as the child becomes older
To avoid use of artificial materials
To be adaptable to patients of any age group
The Fontan Principle
What is a Fontan-type circulation ?
It is an integral part of the entire operation for conditions like tricuspid atresia, pulmonary atresia, hypoplastic left heart syndrome ( HLHS ) and other single ventricle pathology.
We - you, me, cardiologists, surgeons, and everyone else - have been accustomed to thinking of the heart as having four chambers - two atria and two ventricles. These four chambers acting in unison maintain the circulation of blood.
To understand the Fontan circulation, you must make a "leap of imagination". In your mind, eliminate the right ventricle from the heart ! Tough isn't it ? And how can the heart possibly work without a right ventricle ?
Illogical as it may seem, this however was exactly what Dr.Fontan proved with his operation. In his original repair, he connected the right atrium directly to the pulmonary artery, and closed the ASD. Blood entering the right atrium from the veins passed across this surgical connection into the pulmonary artery and to the lungs. It completely bypassed the right ventricle.
Wait a minute ! There must be a flaw in this somewhere. How can the blood enter the lungs if it is not PUMPED IN by the right ventricle ? Well, that really is what makes this procedure unique. Normally the right ventricle will do the pumping. But in tricuspid atresia - and many other conditions in which a Fontan operation is performed - there is NO right ventricle. So blood flows PASSIVELY into the lungs - without being propelled into them by a right ventricle.
Why is lung blood flow so important ?
Because it is the only place in the body that blood can be purified by the addition of oxygen. So when lung blood flow is very low, oxygen supply is reduced to the entire body. This has many harmful effects, since no organ can perform its work normally without oxygen for energy.
So where does the energy for blood flow to the lungs come from ?
First, you must understand that any fluid flowing in a tube will continue to move, becoming slower and slower, until the resistance offered by the tube makes it stop. In a Fontan type circulation, the left ventricle pumps blood into the aorta and arteries. This blood flows at first rapidly into the different organs. The very same force pushes the blood across capillaries, and through the veins, but with lesser force. Slowly, blood enters the right atrium, and then passes across the surgical connection into the lungs - all the while unaided by a right ventricle.
But by its very nature, this flow depends on many factors. For instance, if the blood vessels in the lung are thick walled and narrow before surgery, they will offer very high resistance to passive blood flow. In such a state, the Fontan operation cannot be performed, or will have a high risk of failure, since the extra energy needed to maintain lung blood flow is not available.
Even normally a small amount of resistance will exist across the lung blood vessels. After a Fontan operation, the pressure in the veins will therfore be higher than normal, in order to overcome this resistance and maintain lung blood flow. The elevated pressure in the veins has a few ill effects.
• Children with hypoplastic left heart syndrome require lifelong follow-up by a cardiologist for repeated checks of how their heart is working.
• Virtually all the children will require heart medicines.
• They also risk infection on the heart's valves (endocarditis) and will need antibiotics such as amoxicillin before dental work and certain surgeries to help prevent endocarditis.
Fontan Surgery Cardiac Surgery Videos: Fontan Procedure These pages contain video links to clear images of actual procedures and surgeries made available solely for educational purposes. Their contents may be upsetting to some viewers and discretion should be used.