Fontan procedure

Overview

The Fontan procedure is a specialized surgical intervention designed for individuals with a singular functional heart ventricle due to certain congenital heart diseases present since birth. Under normal circumstances, the human heart comprises four chambers: two atria (upper chambers) and two ventricles (lower chambers). In instances where one ventricle or a principal heart valve doesn’t develop correctly before birth, the remaining functional ventricle must compensate for its counterpart by handling dual responsibilities:

• Pumping oxygen-depleted blood to the lungs for oxygenation.
• Circulating oxygen-rich blood to various body cells.

The Fontan procedure is designed to optimize the flow of oxygen-depleted blood from the body directly to the lungs, bypassing the heart. This is achieved by routing the blood from the lower body straight to the pulmonary artery, which then carries it to the lungs for oxygenation. It’s important to note that the Fontan often follows another surgery called the Glenn procedure. While the Glenn procedure shares a similar goal, it specifically targets the redirection of oxygen-depleted blood from the upper body to the pulmonary artery and, subsequently, the lungs.

After the Fontan procedure, all the oxygen-deficient blood is directed towards the pulmonary artery and then the lungs without initially passing through the heart. This process occurs passively, meaning there is no active pumping ventricle propelling the blood. As a result of the procedure, the sole functioning ventricle’s responsibility is significantly reduced. It can now focus solely on distributing oxygen-rich blood to the body, which can be more efficient for the heart and improve overall circulation.

Reason for undergoing the procedure

Children between the ages of 2 and 15, especially those between 3 to 5, with single ventricle defects may be candidates for the Fontan heart procedure. However, it’s not a universal solution. For a child to qualify, their active ventricle must be strong enough to pump efficiently, and their lungs must be healthy enough to handle passive blood flow. The Fontan procedure is the final step in a series of single-ventricle surgeries, designed to route the child’s oxygen-poor blood directly to the pulmonary artery, bypassing the heart. This blood is then carried to the lungs where it is oxygenated.

Before qualifying for a Fontan heart procedure, children typically undergo at least one of the following surgeries:

• Norwood procedure: Enables the heart’s right side to supply blood both to the body and the lungs.
• Glenn procedure: Redirects oxygen-poor blood from the upper body through the superior vena cava directly to the pulmonary artery.
• Blalock-Taussig-Thomas (BTT) shunt: Channels blood from the subclavian artery (a primary artery) to a pulmonary artery.
• Pulmonary artery band: Adjusts blood flow by reducing the volume directed to the lungs and increasing that which goes to the rest of the body.

The Fontan procedure can treat several heart issues. These include:

• Hypoplastic left heart syndrome.
• Tricuspid atresia.
• Pulmonary atresia with intact ventricular septum.
• Congenitally corrected transposition of the great arteries.
• Hypoplastic right heart syndrome.
• Severe Ebstein’s anomaly.
• Double inlet left ventricle.
• Unbalanced atrioventricular canal defects.

Risks

Complications from a short-term Fontan operation could include:

• Heart failure
• Arrhythmia
• Kidney disorder
• Pleural effusions
• Liver disorder

The following are potential long-term Fontan surgery complications:

• Protein-losing enteropathy, which results in impaired protein absorption during digestion.
• Thromboembolism: an isolated blood clot obstructing a blood vessel.
• Fontan-Associated Liver Disease (FALD).
• Plastic bronchitis: blockage of the airways by fluid accumulation.

Over an extended period, the Fontan procedure may lead to reduced cardiac output, indicating the heart’s diminished capacity to pump blood. In situations where the procedure no longer yields the intended benefits, it is termed as a “failed Fontan.” This might necessitate a heart transplantation, which is occasionally a future consideration for individuals who’ve undergone a Fontan procedure.

Before the procedure

Once your child’s healthcare provider determines that your child is suitable for the Fontan procedure, they will conduct several tests. These tests may include:

• Transthoracic echocardiogram (also known as TTE).
• Electrocardiogram (also known as EKG).
• Heart catheterization.
• An assessment of the pulmonary system, which involves checking your child’s breathing and oxygen levels.
• In some instances, imaging techniques such as Computed Tomography (CT) or Magnetic Resonance Imaging (MRI) might be used.

During the procedure

During the surgery day in the operating room, the healthcare team will provide anesthesia to your child, ensuring a deep, pain-free sleep. The surgeon will then link your child to a specialized machine that momentarily replicates the heart and lungs’ functions, facilitating the connection of the inferior vena cava to the pulmonary artery and directing the oxygen-depleted blood from the lower body directly to the lungs. Concurrently, the surgeon might perform additional heart operations, such as enlarging the opening between the atria or repairing a heart valve. Depending on your child’s cardiac and pulmonary health, a small fenestration may be created in the tube connecting the inferior vena cava and the pulmonary artery. The Fontan procedure typically lasts four to five hours, with the healthcare team providing regular and timely updates throughout.

After the procedure

After the surgery, your child will be moved to an intensive care unit (ICU) for close monitoring before being transferred to a standard hospital room. Once it’s time for discharge, your healthcare provider will offer guidance on how to care for your child at home.

Outcome

The Fontan surgical procedure typically requires a hospital stay of seven to 13 days. Initially, patients spend a few days in the ICU before being transferred to a regular hospital room. About a decade post-surgery, 90% of those who underwent the Fontan procedure are still alive. Survival rates are notably influenced by the initial conditions of the heart and lung anatomy; 30 years after the procedure, 85% of patients are still living.

While life expectancy following the Fontan procedure varies based on the underlying conditions that necessitated the surgery, many patients are now living into their 50s and beyond. It’s worth noting that survival rates are lowest for those diagnosed with hypoplastic left heart syndrome.

After your child has undergone the Fontan procedure, it is crucial to reach out to their healthcare professional if you observe:

• Any discharge of blood or other fluids from their chest incision.
• Indications of fever or any other symptoms suggesting an infection.

Following the Fontan heart procedure, it is recommended that your child has check-ups with their healthcare provider every six to 12 months. Additionally, they might require routine diagnostic tests which include:

• Blood test.
• Electrocardiogram (also known as EKG).
• Radiography of the chest (commonly referred to as a Chest X-ray).
• Magnetic Resonance Imaging of the heart (known as Heart MRI).
• Transthoracic echocardiography (also termed as TTE).
• Monitoring using a Holter device (often called a Holter monitor).
• Ultrasound of the liver and/or Magnetic Resonance Imaging (referred to as MRI).
• Liver function tests conducted annually.