Fontan-associated liver disease (FALD) is a long-term health issue for individuals who have had a Fontan procedure. This life-saving surgery is for children born with a single functioning heart ventricle instead of two, and it reroutes blood flow from the lower body directly to the lungs. While the Fontan operation allows for survival into adulthood, its altered circulation can lead to complications. The liver is one of the most commonly affected organs, and FALD refers to the spectrum of liver problems that develops as a consequence of this unique circulatory state.
Nearly all individuals with a Fontan circulation will develop some degree of liver disease during their lifetime, making an understanding of this condition a part of long-term care.
The Heart-Liver Connection in Fontan Circulation
The cause of FALD lies in the altered blood flow from the Fontan surgery. After the procedure, blood flows passively into the lungs without a dedicated pumping chamber. This leads to a persistent state of elevated pressure in the veins, known as high central venous pressure (CVP), which backs up into the body’s venous system and directly impacts the liver.
This constant high pressure creates chronic passive congestion in the liver’s blood vessels. This congestion means blood does not flow out of the liver efficiently, causing the organ to become swollen. Over time, this pressure damages the liver’s delicate structure by stretching and injuring the cells lining its blood vessels.
A second factor is a potential reduction in the heart’s ability to pump blood, known as decreased cardiac output. The single ventricle may not pump as efficiently as two, meaning the liver might not receive enough oxygen-rich blood to function properly. This reduced blood supply can injure liver cells, and the combination of high-pressure congestion and low-flow oxygen delivery drives the progression of liver damage.
The sustained pressure and lack of oxygen trigger inflammation and cause specialized liver cells to produce scar tissue. This scarring process is the liver’s attempt to repair itself but ultimately leads to the structural damage that defines FALD. The unique, non-pulsating blood flow in the Fontan circulation also contributes to these changes.
Progression and Symptoms
The development of FALD is a slow process that unfolds over many years. The initial stage is liver congestion, which over time leads to the formation of scar tissue, a process called fibrosis. This scarring is the body’s natural response to chronic injury, but in the liver, it disrupts the organ’s normal architecture and function.
As fibrosis progresses, scar tissue increases and can form bridges throughout the liver. If unchecked, this can lead to cirrhosis, an advanced stage of scarring. In cirrhosis, extensive scar tissue hardens the liver, interfering with blood flow and impairing its functions. The rate of progression to cirrhosis varies significantly among individuals.
FALD is often asymptomatic in its early to intermediate stages, which is why it is sometimes called “clinically silent.” Many individuals feel well and have no outward signs of liver trouble even as significant fibrosis develops. This absence of symptoms underscores the need for regular monitoring.
When symptoms appear, they signal more advanced liver disease and warrant immediate medical attention. These can include:
- Persistent fatigue
- Unexplained weight loss
- Abdominal swelling due to fluid (ascites)
- Yellowing of the skin and eyes (jaundice)
- A tendency to bruise or bleed easily
- Confusion or disorientation (hepatic encephalopathy)
Diagnosis and Monitoring
Because FALD often develops without clear symptoms, doctors use a structured surveillance program to detect and track the condition. This monitoring typically begins around 10 years after the Fontan surgery. The goal is to assess liver health, measure any damage, and screen for complications before they become severe.
Monitoring includes blood tests. A liver function panel measures enzyme and protein levels, though these markers can be only slightly abnormal in FALD. Doctors also check the platelet count, as a low count can be an indirect sign of advancing fibrosis.
Non-invasive imaging helps monitor the liver’s structure. An abdominal ultrasound is used to look at the liver’s size, texture, and blood flow. More advanced imaging like elastography (shear wave or magnetic resonance) measures liver stiffness to estimate the amount of fibrosis, as a stiffer liver indicates more scarring.
A liver biopsy, which involves examining a small sample of liver tissue, is the most definitive method for assessing the stage of fibrosis. Because it is an invasive test with some risks, a biopsy is reserved for situations where non-invasive tests are unclear or when more detail is needed for treatment decisions.
Medical Management Strategies
There is no specific cure for FALD, so management focuses on regular monitoring, optimizing Fontan circulation performance, and managing complications from advanced liver disease. The approach is individualized and requires collaboration between cardiologists and liver specialists.
Surveillance for hepatocellular carcinoma (HCC), a type of liver cancer, is a component of FALD management. Individuals with FALD, especially those with cirrhosis, have an increased risk of developing HCC. To detect this cancer early, screening is recommended with blood tests for alpha-fetoprotein (AFP) and liver imaging every six months for those with advanced disease.
Medical therapy aims to support heart function and alleviate liver dysfunction. Cardiologists may prescribe medications to improve the single ventricle’s efficiency, manage heart rhythms, or reduce fluid retention. For complications like fluid buildup (ascites), diuretics may be used. Addressing modifiable risk factors that can harm the liver, such as avoiding alcohol and maintaining a healthy weight, is also part of comprehensive care.
For individuals with a failing Fontan circulation or end-stage liver disease, transplantation may be a consideration. This could involve a heart transplant, a liver transplant, or a combined heart-liver transplant, depending on the clinical situation. These complex procedures are reserved for the most severe cases.