Fontan Operation

Fontan Operation - What it is

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. This procedure is usually performed on patients who only have one effective ventricle to pump blood to both the body and lungs.

In a healthy heart, the left side of the heart pumps oxygen-rich blood to the rest of the body while the right side pumps oxygen-poor blood to the lungs.

The normal heart has 4 pumping chambers, the left and right atria (upper chambers) and the left and right ventricles (lower chambers). The right ventricle pumps oxygen-poor blood to the lungs while the left ventricle pumps oxygen-rich blood to the body. However, babies with 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. Since only one ventricle is pumping normally, both oxygen-rich and oxygen-poor blood get mixed in this chamber. As such, the blood that is pumped to the rest of the body has much lower oxygen levels than normal.

The aim of the Fontan operation is thus to separate the oxygen-poor blood from the oxygen-rich blood. Oxygen-poor blood is directed to the blood vessels leading to the lungs, which allows the single ventricle to only pump oxygen-rich blood to the body. This procedure should 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, it is possible to find un-operated adults who are suitable for the Fontan operation later on in life. These patients will need careful assessment of their heart and blood circulation before surgery. Most patients will be well for many years after the Fontan operation though there are some patients who may develop complications, especially those who completed the procedure at a later age.

Fontan Operation - Symptoms

Fontan Operation - How to prevent?

Fontan Operation - Causes and Risk Factors

Fontan Operation - Diagnosis

Fontan Operation - Treatments

Fontan Operation - Preparing for surgery

Fontan Operation - Post-surgery care

Possible complications of Fontan operation

Arrhythmias

Arrhythmias (abnormal heart rhythm) may develop and are more likely in those patients operated at a later age. Some types of Fontan operations 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.

Protein losing enteropathy (PLE)

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, a transplant may be necessary.

Fluid retention issues

Some patients might have problems with fluid retention in the abdomen or lower part of the legs.

Post-procedure care

Blood thinning medication

All patients who have had 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.

Exercise

Simple and moderate exercise – light jogging, cycling, swimming, brisk walking and yoga – 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

Dental care and hygiene is very important in prevention of endocarditis (infection of the inner layer of the heart). Patients are advised to go for regular dental check-up. Antibiotic prophylaxis (taking preventive antibiotics) is needed to prevent endocarditis before any surgical or dental procedures. Antibiotics may also be required for risky procedures such as body piercing or tattooing.

Liver complications

Patients who have had Fontan operation are at risk for liver cirrhosis (hardening of the liver tissues) or even liver tumours. They are referred to the liver specialist who will do regular scans and gastroscopes to monitor their condition.

Vitamin D

Studies have shown that patients with Fontan operation often have low vitamin D levels and might need oral vitamin D replacement.

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 physiological heart and circulation changes after surgery. In particular, patients who are contemplating pregnancy and also taking warfarin should have a prior discussion with their cardiologist as warfarin can cause serious fetal abnormality.

Additionally, for those who have had the Fontan operation, there is a higher chance of passing the congenital heart defect to their offspring. These patients need careful planning and assessment with close follow-up care jointly by the obstetrician and the cardiologist. Do consult the cardiologist prior to starting a family.

National Heart Centre Singapore (NHCS) and the Department of Obstetrics & Gynaecology from Singapore General Hospital run a monthly specialised joint Cardiac-Obstetric Clinic on the last Monday morning of the month to see all pregnant patients with heart disease. Over the last 10 years, we have managed 200 to 300 pregnant patients with varying severity of cardiac problems through their pregnancy with successful outcomes.

Employment

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.

Maintaining a healthy lifestyle

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 regular exercise and a well-balanced diet.

Follow-up care

All patients with Fontan operation require life-long follow-up with regular assessments.

Fontan Operation - Other Information

NHCS Adult Congenital Heart Disease (ACHD) Programme

This programme was first started in 2003 and currently offers:

ACHD clinic on every Wednesday and Thursday afternoon, and on the first and third Fridays of the month in which an average of 20-30 patients are seen at each session. Besides offering care and follow up of ACHD patients, NHCS also does screening of suspected Marfan patients; close monitoring of ACHD patients during pregnancy (see Pregnancy and Women with CHD) and a monthly joint Cardiac Obstetric Clinic (every last Monday of the month) with obstetricians from Singapore General Hospital (SGH) ; Monthly Transition Clinic in KK Women's and Children's Hospital (KKH) run jointly with paediatric cardiologists from KKH for patients above the age of 16. The aim is to give paediatric patients a smooth transition from paediatric cardiology to adult cardiology services. An average of 100-150 teenagers with congenital heart disease are transferred from KKH to NHCS every year. There is also a monthly Pulmonary Hypertension Clinic (every second Friday of the month) run jointly with a respiratory physician and a rheumatologist from SGH for general as well as congenital patients with severe pulmonary hypertension.
Dedicated twice weekly congenital echocardiography sessions.
Dedicated weekly congenital cardiac catheterisation and intervention (particularly atrial septal defect (ASD), patent foramen ovale (PFO) and patent ductus arteriosus (PDA) device closure).
Surgical interventions including extra-cardiac Fontan procedures for uni-ventricular hearts, pulmonary homograft replacements for Tetralogy of Fallot patients with severe pulmonary regurgitation, Rastalli conduit for patients with pulmonary atresia.
Expertise in nuclear imaging, magnetic resonance imaging (MRI) and multi-slice computed tomography (CT) imaging.
Expertise in pacing, arrhythmia treatment and ablation in congenital patients.
Expertise in cardiopulmonary and exercise testing.
Expertise in heart and lung transplantation for selected patients with end-stage congenital heart disease.
Dedicated ACHD nurse for education, support and care of ACHD patient and their families.

Adult Congenital Heart Disease (ACHD) Clinic

This clinic looks after patients with operated as well as unoperated congenital heart conditions from age 16 onwards. Adults with congenital heart disease need regular monitoring and sometimes further surgical interventions. It also screens suspected Marfan patients and monitors ACHD patients closely during pregnancy.

For more information on NHCS Adult Congenital Heart Disease (ACHD) Programme, visit here.