Overview of Fontan Completion
The Fontan procedure is a key method for treating complex heart defects that involve only one working chamber or “ventricle” in the heart, as opposed to the usual two. This procedure, first introduced by Drs Francis Fontan and Eugène Baudet in 1971, was initially used for a condition called tricuspid atresia, where one of the heart valves doesn’t form properly. Over time, the procedure has been refined and is now called the total cavopulmonary connection. It serves as a treatment option for children with these serious, but rare, heart defects.
These heart conditions occur infrequently, ranging from 0.08 to 0.4 per 1000 live births. They are managed using a series of surgeries that aim to redirect blood flow from the body directly to the lungs, thus avoiding the heart, but only if the pressure in the lungs is sufficiently low. This approach helps to improve oxygen levels in the body and reduces the workload on the heart.
Improvements in both surgical techniques and the way we choose patients for this procedure have led to better results. Now, patients can live longer and with a higher quality of life than before. However, the Fontan procedure still comes with significant health challenges due to its effect on the body outside of the heart itself. Issues can arise in general health status and complex complications throughout the body.
Research is ongoing in understanding the long-term outcomes of the Fontan procedure, working to address any gaps in our current knowledge, and coming up with new strategies to lessen complications and enhance quality of life for these patients. This involves looking at the history of the procedure, the techniques involved, how patients are chosen for this operation, and how best to manage patients long-term once they’ve undergone the procedure, whilst identifying current challenges and future opportunities in treatment.
Anatomy and Physiology of Fontan Completion
The Fontan procedure is a type of surgery done to improve blood flow in people who have a specific heart defect present at birth, where they have only one functioning heart chamber (ventricle) instead of the usual two. Normally, the heart has four chambers, two small ones – the atria, and two large ones – the ventricles. But in these patients, only one ventricle does all the work. This can create significant health challenges.
The goal of the Fontan procedure is to reroute blood flow, so it bypasses the heart and flows directly to the lungs. This allows the single functioning ventricle to concentrate on pumping blood to the rest of the body. However, the single ventricle needs to be efficient, the resistance in the lungs’ blood vessels needs to be low, and the rerouted paths must not be blocked for this “bypass system” to work.
The Fontan procedure was initially designed to treat a heart defect called tricuspid atresia but is now used for various congenital heart defects, including hypoplastic left heart syndrome. The surgery is often carried out in stages, starting with procedures like the Norwood or Glenn to ensure the best possible outcome and survival rate.
Successful Fontan circulation depends on low resistance in the lungs’ blood vessels and a well-functioning ventricle. But, in the long run, it can cause various health issues, such as high blood pressure in the veins, reduced flow of blood back to the heart, and low blood flow out of the heart. Continuous long-term effects of the Fontan circulation could ultimately lead to “Fontan failure,” emphasizing the need for meticulous management and monitoring of these patients throughout their lives.
Why do People Need Fontan Completion
The Fontan procedure is a type of heart surgery that’s usually performed in children who were born with heart defects. Specifically, these children usually have a condition where their heart has just one working ventricle. A ventricle is a chamber in the heart that pumps blood out to the body. Normally, the heart has two ventricles; one to pump blood to the body and one to the lungs.
In the Fontan procedure, the circulation of the body is rearranged so that the single working ventricle pumps blood to the body, while the blood flow to the lungs is directed from the veins. Because of this procedure, the heart can work effectively with only one ventricle.
Children suffering from any one of these conditions might need the Fontan procedure:
– Tricuspid atresia
– Hypoplastic left heart syndrome (most common)
– Hypoplastic right heart syndrome
– Pulmonary atresia with intact ventricular septum
– Double-inlet left ventricle
– Double-outlet right ventricle
– Unbalanced atrioventricular canal defects
– Conditions related to abnormality in the heart’s valves (Ebstein anomalies) that are suitable for Fontan correction
– Corrected abnormality in the great vessels of the heart
However, not all children with these conditions are suitable for the Fontan procedure. There are specific factors the doctors consider to decide on the best course of action. Those include:
– Lower than usual resistance in the pulmonary vessels
– Well-working single ventricle
– No significant issues with the heart’s valve
– Normal rhythm of the heart or controlled heart rhythm disorders
– No blockages in the pulmonary artery
– Appropriately sized pulmonary arteries
The Fontan procedure is scheduled after certain preliminary surgeries, like the Norwood or Glenn procedure. These surgeries help the body adjust and reduces the risks associated with the Fontan procedure. The best age to perform this procedure is between 2 to 5 years old. This is because at this age, the resistance in their pulmonary vessels is low enough for the procedure to be most effective. By taking all these factors into account, the Fontan procedure can be a successful long-term solution for many kids with these specific heart conditions.
When a Person Should Avoid Fontan Completion
The Fontan procedure is a complex heart operation meant to help people with a condition called ‘single-ventricle physiology.’ This procedure can be a lifesaver for many patients; however, it doesn’t work for everyone. Its success greatly depends on choosing the right patients – taking into account certain factors that might complicate the procedure, or make it too risky.
There are some clear cases where the Fontan procedure shouldn’t be done:
- If the patient’s lungs have high resistance to blood flow (technically called ‘high pulmonary vascular resistance’), the procedure won’t work. This resistance stops the blood from flowing easily into the lungs, which is crucial for this type of surgery. If the measure of this resistance is over 3 Wood units/m², then the surgery should not be done. Additionally, if the pressure in the lungs’ blood vessels is too high, the surgery outcomes tend to be worse.
- If the patient’s heart is not working properly (known as ‘severe ventricular dysfunction’), the procedure would not be beneficial.
- If there’s severe ‘atrioventricular valve regurgitation’ or in simple terms, if the heart valves aren’t closing properly and are allowing blood to flow in the wrong direction. This causes an overload in the heart, making it work harder than it should, and in turn weakening the effectiveness of the Fontan procedure.
- If the patient’s blood vessels in the lungs are narrow or underdeveloped (known as ‘pulmonary artery hypoplasia or obstruction’), it could make the procedure unworkable.
- If the patient is suffering from severe cyanosis or hypoxemia, which means there is not enough oxygen in the blood, the Fontan procedure may worsen the condition.
- End-stage liver or kidney disease can raise the risk of surgery and lower the chances of long-term survival.
There also some conditions that could make the Fontan procedure more risky but don’t necessarily mean it can’t be done:
- Additional blood vessels that shouldn’t be there can cause too much blood flow into the lungs and would need to be fixed before surgery.
- If arrhythmia, or an irregular heartbeat, is present, it could destabilize the circulation of blood in the Fontan procedure.
- Severe issues with the spine or the structure of the chest can affect blood flow in the lungs and reduce the chances of successful surgery.
- If the heart is too stiff (poor ventricular compliance), then it cannot adapt to the changes made in the Fontan procedure. This condition could lead to diastolic dysfunction which can cause inadequate blood flow to the body.
- If the patient has previously had blood clots (chronic thromboembolic disease), a Fontan procedure can increase the risk of more clots forming.
Equipment used for Fontan Completion
The Fontan procedure, a method of surgically repairing certain heart defects present from birth, must be conducted in a specific type of operating room equipped with special tools. This surgery room also needs to be staffed by a surgical team that’s highly-skilled and experienced in complex heart repairs. Ensuring all the necessary equipment is ready and working is crucial to the success of the procedure.
In particular, when doing a type of Fontan procedure called ‘extracardiac Fontan’, it’s very important to have a special tube or graft material at hand. This tube or material is used to make the connection between the body’s major blood vessels and the lungs. This step aids in improving the blood flow in the body.
Thorough preparation is key, which involves double-checking supplies and making sure all essential tools and materials are available. This rigorous process helps to prevent any delays during surgery and also helps achieve better results for the patients.
Who is needed to perform Fontan Completion?
The Fontan procedure, which is a specific type of heart surgery, requires a team of experienced medical professionals. In this team, you will find a heart surgeon who specializes in congenital (birth-related) heart conditions, a pediatric cardiac anesthesiologist who will manage the anesthesia during the operation, and a first surgical assistant who helps the surgeon. You will also have a surgical technician, a surgical nurse and a perfusionist who is an expert in managing the heart-lung machine. Lastly, there is a pediatric cardiologist, who can read heart scans, involved in the process.
After the procedure, it’s preferable that the patient stays in a special part of the hospital that focuses on heart conditions that people are born with – this is called a congenital cardiac intensive care unit. The doctors and nurses, known as pediatric intensivists, in this unit are experienced in the special care that patients with single ventricle heart defects (where only one ventricle, or lower heart chamber, is functioning properly) need. So, they know how to look after them post-surgery, especially after the Fontan procedure.
Preparing for Fontan Completion
Preparation for a complex heart surgery called the Fontan procedure is very important to ensure the best possible result and reduce the risk of complications during and after the operation. The main aim is to make sure the patient is suitable for the surgery and any potential issues have been addressed.
Patients must meet certain conditions to have the Fontan procedure, including certain age range (4 to 15 years old), healthy rhythm of the heart, normal blood flow from the vena cava (the body’s largest vein), normal size of the right atrium (one of the four chambers of the heart), low pressure in the pulmonary artery (the vessel that carries blood from the heart to the lungs), and a normal heart function. Furthermore, the pulmonary arteries must be of appropriate size and the heart must be free of any sort of valve leakage.
Before the Fontan procedure, there are several tests and evaluations that the patient goes through to confirm that the surgery would be beneficial and safe. These include ECG (to check the heart rhythm), Ultrasound of the heart (to check heart function, valve health, and size of the pulmonary arteries), lung tests (to ensure adequate blood flow to lungs), and cardiac catheterization (a procedure done to observe and measure the pressure of blood vessels and heart’s chambers).
In addition, a few steps are taken to further improve the patient’s condition before the surgery. If the patient’s pulmonary resistance is slightly higher, additional treatments can be provided to lower it. Similarly, if the patient has any nutritional deficiencies, they would be provided with dietary supplements. Any abnormal heart rhythms would also be treated. If the patient has low blood count or low platelet count, these would be corrected to ensure optimal oxygen supply and reduce risk of bleeding during the surgery. All infections would be treated before the surgery to reduce risk of complications. At the same time, the patient’s family would be educated about the procedure, its potential risks, and the care the patient would need after the surgery.
The surgical team will also review the patient’s previous surgeries, if any, and any variations in the patient’s heart structure in order to plan the most appropriate surgical method for the Fontan procedure. Such thorough preparation can help patients have the best chance for a successful operation and improved health in the long run.
How is Fontan Completion performed
The Fontan procedure is a complex heart surgery performed on patients with a specific type of heart defect where they are born with only one ventricle, or part of the heart that pumps blood. This surgery reroutes the blood flow directly from the body into the lungs, bypassing the heart. Patients who undergo this surgery are typically put under general anesthesia and have to be prepared for a procedure that reroutes their blood flow. The surgical area has to be reopened as this surgery is usually a part of a series of surgeries. In some recent studies, there has been a new “clamp-and-sew” surgical technique introduced which doesn’t require rerouting blood flow.
The idea for this operation was proposed by Francis Fontan and involves directly connecting the top part of the heart (the right atrium) to the lung’s artery. The surgery is usually done after another procedure called the Glenn procedure. The success of the Fontan procedure heavily depends on the right size of the lung’s arteries and the right atrium of the heart to ensure the blood flows smoothly and faces no resistance.
The Fontan procedure has continuously been improved over the years and there are now primarily two techniques used: the extracardiac conduit (EC) and the lateral tunnel (LT). The LT technique involves constructing a pathway within the heart to connect the vena cava (the large vein that carries deoxygenated blood from the body back to the heart) directly to the pulmonary artery. Both of these methods usually require rerouting blood flow, but in some situations, the EC method can be completed with minimal or no bypass.
Research shows that there is no significant difference in survival rates and overall outcomes between two methods. However, the EC method might have some benefits, like reducing the likelihood and risk of irregular heart rhythms. The EC method also gives the surgeons an option to create a “fenestration,” or a small opening, to help manage the pressure inside the heart and improve the blood flow. Some surgeons prefer the EC method because of shorter operating times and its potential for preserving the function of the heart and lungs.
The Fontan procedure can be categorized depending on the method used to perform it and whether or not a “fenestration” was created. One type even includes connecting the veins which carry blood from the liver to the lungs. Furthermore, there is a technique which allows both ventricles to send blood into their respective blood vessels, supplemented by an extracardiac connection to enhance blood flow to the lungs.
The Fontan procedure has revolutionized the way we treat heart defects since it was first introduced. It is typically performed as part of a series of surgeries, such as the Norwood and Glenn procedures, which prepare the patient’s body for the rerouting of blood flow. The success of the procedure heavily depends on the condition of the patient’s heart and the successful management of any complications after the surgery. Lifelong monitoring is crucial as prolonged exposure to the rerouted blood flow may lead to more serious complications like “Fontan failure,” characterized by reduced blood flow, increased stress on the heart, and long-term weak heart performance.
Possible Complications of Fontan Completion
The Fontan procedure is a type of heart surgery often used in patients with a certain type of complex heart defect called a “univentricular heart”. However, any kind of surgery has possible complications.
Data from the Society of Thoracic Surgeons reveals that on average, about 1.2% of people who have this surgery pass away due to complications related to the surgery, and it usually requires a hospital stay of about 13 days. The risk of passing away is highest in the first 5 years after the surgery but then it begins to level off after 15 years. One study reported survival rates of 82% after one year, 74% after five years, and 71% after ten years.
Complications related to the surgery may involve various parts of the body and range from minor symptoms to major health issues. These can include bleeding, abnormal heart rhythms, buildup of fluid in the space covering the lungs, liver fibrosis (scarring), heart failure, accumulation of fat-filled fluid in the chest (chylothorax), a bluish appearance of the skin due to lack of oxygen (cyanosis), difficulty with physical exercise, issues with the root of the aorta (the main artery in the body), problems with the functioning of the ventricles (chambers of the heart), problems with the blood vessels in the lungs, a condition where the body loses too much protein from the digestive tract (protein-losing enteropathy), blood clots, kidney disease, liver disease, inability of veins to properly carry blood back to the heart (venous insufficiency), and even death.
Research is ongoing to better understand why some patients experience more complications than others. Some studies suggest that patients whose heart has a dominant right ventricle may face a higher risk of passing away. Other research is examining how problems with lymphatic drainage (the system responsible for draining toxins from our tissues) might lead to complications. For example, two conditions called protein-losing enteropathy and plastic bronchitis are thought to be related to poor lymphatic drainage and can occur in up to 5% of all Fontan patients. These conditions significantly raise the risk of passing away, up to 50%, five years after diagnosis.
Plastic bronchitis, a rare complication, is marked by the formation of blockages in the airways. It can be life-threatening and often requires hospitalization.
Protein-losing enteropathy is seen not just in patients after the Fontan procedure, but also in various other heart conditions. It is thought to be caused by the build-up of pressure in the veins, leading to the loss of protein in the gut. However, this isn’t entirely understood as not all patients with high venous pressure develop this condition.
One explanation that has been suggested is that protein-losing enteropathy might result from a combination of slightly raised venous pressure and a marked reduction in the blood flow out of the heart, limiting blood flow to the intestines and other organs. There is also a link between this condition and high blood pressure in the arteries supplying the intestines. Higher pressure in these arteries corresponds to reduced blood flow in the intestines, which may play a role in protein-losing enteropathy developing in patients after the Fontan procedure.
Increased pressure in the veins can also contribute to several liver diseases including liver fibrosis and liver cancer.
Overall, while the Fontan procedure can be life-saving, it is not without risks, and ongoing research is attempting to better understand and manage these complications to improve patient outcomes.
What Else Should I Know About Fontan Completion?
The Fontan procedure is a significant medical advancement in the treatment of a type of heart disease where a person is born with only one working ventricle or chamber in their heart. Before the 1940s, this condition was almost always deadly. However, today, thanks to a series of treatments leading up to the Fontan procedure, people with this condition can live longer, healthier lives.
Currently, it’s estimated that between 50,000 to 70,000 people living with the health improvements provided by the Fontan procedure worldwide, and this number is expected to double in the next 20 years. This increase highlights the growing number of people benefiting from this procedure and the need to keep improving their long-term care and support.
A study published in The Journal of the American College of Cardiology in 2017 showed that the Fontan procedure has been very successful, resulting in 90% of patients living without the need for a transplant for 12 years. However, having a lower ability to perform physically demanding activities might increase the risk of dying or needing a transplant. As more and more children with single-ventricle conditions are living longer, doctors are turning their attention to managing complications that may occur due to the long-term effects of the Fontan procedure.
Continued research is crucial to find new ways of improving the lives of those who undergo the Fontan procedure. This research will aim to increase the number of years patients can live without a transplant and minimize the complications and health issues they might experience.
