The normal heart has 4 pumping chambers, the upper chambers are named atrias and the lower pumping chambers are named ventricles. The right ventricle pumps poor-oxygen blood to the lungs while the left ventricle pumps rich-oxygen blood to the body. However 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.
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.
The aim of the Fontan operation is to separate the poor-oxygen blood from mixing with the rich-oxygen blood, 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 there are incidences where there are unoperated adults who are suitable for the Fontan operation. These patients will need careful assessment of their heart and circulation before surgery.
Most patients will be well for many years but there are some patients who may develop complications especially those done at a later age.
Blood thinning medication
All patients with Fontan operation are prescribed blood-thinning medication by the cardiologist. Some patients may be required to take warfarin, a blood thinning medication which helps to reduce the risk of blood clot formation. These patients will require blood-thinning level (INR- International Normalised Ratio) to be monitored regularly. This medication must not be stopped abruptly without your cardiologist’s instructions.
Arrhythmias (abnormal heart rhythm) may develop and are more likely in those patients operated at later age. Some types of the Fontan operation also carry a higher risk of arrhythmias due to enlargement and scarring of the atrium, causing problem with the heart’s electrical conduction. Treatment options may include medication, insertion of pacemaker and radiofrequency ablation procedure.
Simple and moderate exercise may be well tolerated and is encouraged. Regular exercise may improve the general well-being of patients. However do avoid competitive and contact sports especially for patients on warfarin.
Prevention of endocarditis
Antibiotic prophylaxis is prescribed to prevent endocarditis (infection of the inner layer of the heart) before any surgical or dental procedures. Antibiotics may also be required for risky procedures such as body piercing or tattooing.
Family planning and pregnancy
It is important to choose a safe and effective contraception, as not all options are suitable. Do discuss the different methods of contraception with the cardiologist.
Women who have undergone the Fontan operation carry a higher risk in pregnancy due to the anatomical heart and circulation changes after surgery. In particular, patients who are also taking warfarin should not contemplate pregnancy without prior discussion with the cardiologist as warfarin can cause serious fetal abnormality.
These patients need careful planning and assessment with close follow-up care jointly by the obstetrician and the cardiologist. Do consult the cardiologist prior starting a family.
It is possible for patients who have undergone the Fontan operation to get a full-time or part-time job. However, they should avoid jobs that require heavy labour and carry a higher risk of injury, especially for patients under warfarin therapy.
Some Fontan patients may develop a condition called Protein-Losing Enteropathy (PLE) where protein is lost through the gut. This is a very serious condition and the exact cause is unknown. Generally the treatment involves taking medication and for severe cases, transplant may be necessary.
Good health maintenance
Acquired heart disease such as coronary artery disease and enlargement of the heart will pose additional risk to the Fontan patient’s health. It is important to maintain an overall good health with reasonable exercise and well balanced diet.
All patients with Fontan operation require life-long follow-up with regular assessments.
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