Information for patients and parents about the Fontan Operation

  • Why do children need a Fontan Operation?

    Affected children are blue ('cyanosed') because their arterial (red) and venous (blue) blood mix together. Such patients have one of several cardiac abnormalities that mean that the lung circulation cannot work independently from the body circulation. These problems may require a Fontan operation.

    The main defects in this category are:

    • Tricuspid Atresia
    • Pulmonary Atresia with underdeveloped right ventricle
    • Double inlet left ventricle
    • Double outlet right ventricle with associated defects that prevent repair
    • Hypoplastic left heart syndrome
    • Other defects that cannot be fixed by other types of surgery

    In all these situations, where a Fontan operation is recommended, the problems in the heart make it impossible or extremely hazardous to 'repair' the defect in a way that would allow two ventricles to support the two circulations separately.

    The aim of the operation is to improve oxygen levels, by redirecting venous (blue) blood directly to the lungs. This produces two separate circulations and a decreased workload on the heart, but means that only one ventricle functions as the 'pump' (driving blood through the body circulation first and then into the lung circulation afterwards, before it returns to the ventricle to start again).

    This operation works best if:

    • there are good (normal) sized lung (pulmonary) arteries
    • there is low pulmonary vascular resistance - allowing the blood to flow easily through the lung
    • circulation with no need for high pressure to drive it
    • there is a healthy / vigorous ventricle to pump blood round the circulation
    • there is no valve dysfunction (leak) that allows blood to flow back across closed valves

    The decision for operation?

    Many children or adults who are candidates for this type of surgery will have had previous surgery and / or catheter procedures. Before the Fontan operation can be performed they will need comprehensive review with several tests, probably including an up-to-date catheter test.

    After the results have been discussed by the doctors and surgeons the patient / family will need to see the surgeon to learn more about the operation and what benefits it may achieve.

    It is important that the family know that the Fontan operation is not a ëcureí and that patients after this surgery will need long-term follow-up.

    The Operation

    The Fontan operation can be done in several different ways. At the Royal Childrenís Hospital there have been three main ways of ensuring as much blood flow to the lungs as possible.

    1. Extracardiac Fontan

    • The superior vena cava is connected to the right pulmonary artery (this may have been done at an earlier 'bi-directional cavo-pulmonary shunt' operation)
    • The inferior vena cava is re-routed through a Gore-Tex tube (conduit), which runs outside the heart and is connected to the Pulmonary Arteries.
    • The atrial septum is removed (this may have been done already at previous surgery).
    • Blood returns via the pulmonary veins into the left atrium and may also pass to the right atrium freely > ventricle > Aorta > body.
    23a_Fontan_operation


    2. Lateral tunnel Fontan

    • Venous return is redirected to the pulmonary artery and into the lungs by joining the superior vena cava and the inferior vena cava by a large patch that creates a tunnel through the right atrium.
    • The vena cavas are then connected directly to the pulmonary arteries above the heart.
    • The atrial septum is removed.
    • Blood returns via the pulmonary veins into the now independent left atrium > ventricle > Aorta > body.

    23b_Fontan_operation

    3. Atriopulmonary Connection (now rarely used)

    1. The right atrium is connected to the pulmonary artery.
    2. If the tricuspid valve is present it needs to be closed off with a patch (to prevent blood flowing into the ventricle).
    3. The atrial septal defect is closed.
    4. Blood now flows from the superior and inferior vena cava through the right atrium and into the pulmonary arteries.
    5. Blood returns via the pulmonary veins into the left atrium > ventricle > aorta > body.(image here)

    Admission arrangements

    One or two days before surgery the patient will need to come to the cardiac ward, for preliminary tests.

    While there he or she will have:

    • a chest xray
    • a cardiac echo scan
    • blood tests
    • E.C.G.
    • height and weight measured

    The family will be visited by:

    • Cardiologist/Surgeons
    • Anaesthetist 

    Nurses from this ward take the family to visit the Intensive Care Unit, which introduces them to the area that the patient will return to after the operation.

    The day of surgery

    The anaesthetic and operation will take about 5 hours or longer.

    After the operation the patient will be in the intensive care unit.

    Because there is no separate ventricle to pump blood to the lungs it is important that blood flow to the pulmonary arteries is increased in every possible way! Such as...

    • Being nursed with pillows under the head and two pillows under the legs to assist the flow of blood back to the heart.
    • To help the heart contract, an infusion of a drug to strengthen the heart beat, such as 'Dopamine', may be needed. Drugs such as 'phenoxybenzamine' / 'nitroprusside' may also be used to open up blood vessels and reduce resistance in the circulation. These drugs allow blood to flow more easily and therefore reduce the effort required by the heart.

    The intensive care team will make sure that the patient is breathing on his / her own as soon as possible (usually less than 12 hours). This will also assist venous return, as the need for an artificial ventilator (positive pressure ventilation) makes it more difficult for blood to return to the heart and ultimately, into the lungs and out again.

    Heart function is also optimised by administering adequate fluid or blood to make sure that the pressure in the veins carrying blood back to the heart, and from there to the lungs, is maintained high enough to promote good blood flow through the lungs.

    • Unfortunately because the pressures in the veins are higher than normal (inferior vena cava and superior vena cava), it also creates some problems.

    While the body is trying to adjust to this the patient may be very prone to leakage of fluid into the sacs around the lungs or elsewhere, which can cause ëpleural effusionsí (fluid around the lungs), ascites (fluid in the abdomen) and liver congestion / enlargement.

    Therefore the nurses are carefully noting the amount of fluid that is lost and is taken in. The absolute minimum of fluid intake is given during this early stage to try to minimise these problems.

    • The family can be at the patientís side as often as possible
    • Hopefully he / she will be back in the ward within about 24 hours
    • If he / she gets bored, the play or music therapist will provide some entertainment!!

    Returning to the ward

    • When all is well, the patient and family can return to the cardiac ward. The chest drain tubes may still be there, as will be the pressure lines and pacing wires.
    • The patient may well be persistently thirsty!! He / she is still allowed only 50% of normal fluid intake (to decrease congestion and the risk of fluid collections around the lungs or elsewhere). This will be gradually increased but some restriction on fluid intake may even continue at home!
    • Because of this fluid restriction, nutrition may suffer and therefore the patient can be more prone to infection.

    To avoid this:

    • The Dietitian makes sure that there are enough calories in the diet.
    • The Physiotherapist visits twice a day to encourage deep breathing and coughing.
    • The patient is weighed daily to help in fluid assessment.
    • Nurses still watch closely for complications such as pleural effusions (fluid around the lungs), or pericardial effusion (fluid collection around the heart).
    • The patient is commenced on 'anticoagulant' medications (Warfarin or Aspirin) to prevent blood clots forming too readily. This is because of more sluggish blood flow in the main veins and lung circulation, and an increased risk of blood clot in these areas or in the heart. While on these drugs it is important to remember that he or she may bruise easily or bleed for longer than normal after an injury. The patient may need to continue with these medications forever!
    • The family can be in the ward as much as they like, Mum and Dad can even stay overnight.
    • The hospital stay is at least two weeks after surgery and is often longer because of the fluid collections.

    Going home

    • When he / she leaves the hospital the patient will need to have a blood test once or twice a week at first and will need to be checked by the cardiologist.
    • After the first month these visits will become less frequent.
    • He / she will be on several medications that will be reduced gradually over the next two to three months.
    • As the patient gradually gets back to normal and increases activity fluid intake will be allowed to return to normal and most of the medications can be ceased. This should only be done however as and when the cardiologist gives instructions.

    The future

    • Most patients will be able to return to normal activity over the first three months or so.
    • They should increase their activities gradually to a stage where they are engaging in regular light to moderate exercise. Moderate physical exertion is generally good for them, but they / their parents should seek advice from their cardiologist about what activities are suitable.
    • Most Fontan patients will be free of 'Cyanosis' (blueness) and will have oxygen levels close to normal.