Long-Term Fontan Circulation & Complications

After the Fontan procedure, your child’s heart functions in a way that is unique in the medical world. Instead of the heart pumping blood to the lungs, the blood flows there “passively” ^[1]. This creates a stable and durable circulation for many, but it is not a “normal” heart. Over years and decades, this unique “plumbing” can put stress on other organs in the body ^[2][3].

The “Passive” Flow Challenge

In a typical two-ventricle heart, the right ventricle acts like a booster pump to push blood through the lungs. In a Fontan circulation, that pump is missing. To keep blood moving forward, the pressure in the veins must remain high ^[1][4].

Think of it like water in a pipe: without a pump, you need to increase the pressure at one end to keep the water flowing. This “back pressure” is necessary for the lungs, but it means the liver, gut, and lymphatic system are under constant, higher-than-normal pressure ^[5][6].

While some complications develop slowly, others can present abruptly. It is crucial to monitor for changes and communicate early with your team. Treatments range from simple medications to catheter procedures, surgery, or sometimes transplant evaluation, depending on the severity of the problem.

Lymphatic Complications: PLE and Plastic Bronchitis

The lymphatic system is the body’s “drainage” network. When venous pressure is high, the lymphatic system can become overloaded or start to “leak” into places it shouldn’t ^[6][2].

• Protein-Losing Enteropathy (PLE): This happens when lymphatic fluid (rich in protein) leaks into the gut ^[2].
  • Signs: Rapid or significant swelling (edema) in the legs, face, or abdomen, persistent diarrhea, and marked lethargy ^[7][2].
  • Action: Rapidly increasing swelling requires urgent medical evaluation.
• Plastic Bronchitis: This occurs when lymphatic fluid leaks into the airways and hardens into rubbery, “plastic-like” casts ^[2].
  • Signs: A severe, “barky” cough, wheezing, and coughing up white or tan branching material that looks like a small tree (a cast of the airway) ^[7].
  • Action: Call emergency services immediately for severe breathing trouble, inability to speak normally, or cyanosis. Contact your Fontan team urgently if you suspect your child is coughing up casts.

Fontan-Associated Liver Disease (FALD)

Because the liver is located just “downstream” from the heart, it feels the effects of this high venous pressure more than almost any other organ ^[5].

• What it is: Over time, the constant pressure can cause the liver to become congested, leading to fibrosis (scarring). In some cases, this can progress to cirrhosis ^[8][9].
• The Challenge: FALD is often “silent.” A child or young adult may have normal liver blood tests even if scarring is present ^[8].
• Monitoring: Your team will use specialized imaging and laboratory trends to evaluate liver health ^[10][11].

Heart Rhythm and Squeeze

As the years go by, the single ventricle and the upper chambers of the heart (atria) can change in size or shape, which may lead to two other long-term concerns:

1. Arrhythmias: The heart may develop an irregular, slow, or fast rhythm, such as atrial fibrillation, intra-atrial reentrant tachycardia, atrial flutter, or sinus-node dysfunction. Because the Fontan circulation depends so heavily on a steady rhythm, an arrhythmia can make a person feel very tired, short of breath, or cause palpitations quickly ^[12][13].
2. Ventricular Dysfunction: After decades of doing double duty, the single ventricle may begin to weaken, or the valves may begin to leak (regurgitation) ^[14][15].

Lifelong Vigilance

The key to a healthy future is lifelong follow-up with specialized Adult Congenital Heart Disease (ACHD) centers ^[3][16]. These specialists use a variety of regular checks (MRIs, echoes, and blood tests) designed to catch early signs of stress before they become major problems ^[3][11]. By monitoring the liver, heart, and lungs together, your team can adjust treatments to support the Fontan circulation for as long as possible ^[5][2].