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The Fontan procedure, or Fontan/Kreutzer procedure, is a palliative surgical procedure used in children

with complete congenital heart defects.

It involves diverting the venous blood from the right atrium to the pulmonary arterieswithout passing

through the morphologic pulmonary ventricle. It was initially described in 1971 by Dr Fontan and Dr

Kreutzer separately as a surgical treatment for tricuspid atresia.Indications The Fontan procedure

hasmore recently been used in pediatric situations where an infant only has a single effective ventricle,

either due toheart valve defects (e.g. tricuspid or pulmonary atresia) or an abnormality of the pumpingability of the heart (e.g. hypoplastic left heart syndrome, hypoplastic right heart syndrome), or has

complexcongenital heart disease where a bi-ventricular repair is impossible or inadvisable. Children with

hypoplastic left heart syndrome have a single effective ventricle supplying blood to the lungs and the body

(either from birth or after an initial surgery e.g. Norwood procedure). They are delicately balanced between

inadequate blood supply to the lungs (causing cyanosis) and oversupply to the lungs (causing heart failureIn

addition, the single ventricle is doing nearly twice the expected amount of work (because it has to pump

blood for both lungs and body). As a result, these children can have trouble gaining weight, and are also

vulnerable to decompensation in the face of otherwise minor illnesses (even a common cold). Sometimes

medications (e.g. diuretics) can help them through this stage. Therefore, when either they are large

enough, and if the pressure in the pulmonary arteries is low enough, these children (see example on

http://ravinduson.yolasite.com ) are referred for Fontan procedure commonly after 2 years of life.

Contraindications

After Fontan, blood must flow through the lungs without being pumped by the heart. Therefore children

with high pulmonary vascular resistance may not tolerate a Fontan procedure. Often cardiac

catheterization is performed to check the resistance before proceeding with the surgery.

This is also the reason a Fontan procedure cannot be done immediately after birth; the pulmonary

vascular resistance is high in utero and takes months to drop.)

Types

http://upload.wikimedia.org/wikipedia/commons/0/05/Fontan_procedure.svg

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There are three different types of Fontan procedure:

Atriopulmonary connection (the original)

Described by Fontan and Kreutzer.

Intracardiac total cavopulmonary

connection (lateral tunnel)

Extracardiac total cavopulmonary

Connection

Approach

The first stage, also called a Bidirectional Glenn

procedure or Hemi-Fontan (see also Kawashima procedure), involves redirecting oxygen-poor blood from

the top of the body to the lungs. That is, the pulmonary arteries are disconnected from their existing blood

supply (e.g. a shunt created during a Norwood procedure, a patent ductus arteriosus, etc). The superior

vena cava (SVC), which carries blood returning from the upper body, is disconnected from the heart and

instead redirected into the pulmonary arteries. The inferior vena cava (IVC), which carries blood returning

from the lower body, continues to connect to the heart.

At this point, patients are no longer in that delicate balance, and the single ventricle is doing much less

work. They usually can grow adequately, and are less fragile. However, they still have marked hypoxia

(because of the IVC blood that is not fed into the lungs to be oxygenated). Therefore most patients are

referred for another surgery.

The second stage, also called Fontan completion, involves redirecting the blood from the IVC to the lungs

as well. At this point, the oxygen-poor blood from upper and lower body flows through the lungs without

being pumped (driven only by the pressure that builds up in the veins). This corrects the hypoxia, and

leaves the single ventricle responsible only for supplying blood to the body.

Post-operative complications

Early

children can have trouble with pleural effusions, fluid building up around the

lungs. This can require a longer stay in the hospital for drainage with chest tubes. To address this risk, some

surgeons make a fenestration (a small hole) from the venous circulation into the atrium. When the pressure

in the veins is high, some of the oxygen-poor blood can escape through the fenestration to relieve the

pressure. However, this results in hypoxia, so the fenestration may eventually need to be closed by an

interventional cardiologist.

Late Complications

Children can have trouble with atrial flutter and atrial fibrillation because of scarring in

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the atrium, especially if the connection of IVC to pulmonary arteries involved an intracardiac baffle (instead

of an extracardiac conduit). This sometimes requires treatment such as radiofrequency ablation. There are

other long-term risks, including protein-losing enteropathy and chronic renal insufficiency, although

understanding of these risks is still incomplete. Some patients require long-term blood thinners.

The Fontan procedure is palliative, not curative.

But in many cases it can result in normal

or near-normal growth, development,

exercise tolerance, and good quality of life.

In some cases, patients will eventually

require heart transplantation