
Information for Patients and Families
At Additional Ventures, our mission is to support research to improve the lives of patients with single ventricle heart disease. We are committed to finding both new and better treatments, including developing cures, for all patients, no matter their age, stage, or experience.
Single ventricle heart disease affects about 35 out of every 100,000 newborn children in the US. There has been huge progress in its treatment over the last 50 years, but there is so much more to do. We believe that single ventricle heart disease is a solvable problem and we see a future where patients can live full, healthy lives.
Here, you will find more information about single ventricle heart disease, why more research is needed, and details of our Research Roadmap for solving this complex and challenging disease.
Single Ventricle SOURCE
Understanding Single Ventricle Heart Disease
Single ventricle heart disease (or a single ventricle heart defect) is a type of heart problem that patients are born with. Having single ventricle heart disease means one ventricle does not form properly when a baby is developing in the womb, leaving only one ventricle working effectively. For example, one ventricle may be too small or missing a valve. Most single ventricle hearts can be detected at a 20-week pregnancy scan or after birth by echocardiogram.
While there has been a lot of research into single ventricle heart disease, we still don’t fully know why these defects occur. They are thought to be caused by a combination of different factors, including genes.
How the Heart Works
To understand what single ventricle heart disease is, and how it affects people, it is first important to know how a healthy heart works.
The heart pumps blood around the body to deliver oxygen and nutrients. The heart has four chambers: the right atrium, right ventricle, left atrium and left ventricle. Valves control the direction of the flow of blood.
The workings of a healthy heart
How a single ventricle heart works
Types of Single Ventricle Heart Disease
There are several different types of single ventricle heart disease, some of which are:
- Hypoplastic Left Heart Syndrome (HLHS)
- Tricuspid Atresia
- Double Inlet Left Ventricle (DILV)
- Double Outlet Right Ventricle (DORV)
- Single Left Ventricle (sometimes called Hypoplastic Right Heart)
- Pulmonary Atresia with Intact Ventricular Septum (PA-IVS)
- Unbalanced Atrioventricular Canal
Treatments for Single Ventricle Heart Disease
If single ventricle heart disease is not treated, it is fatal. There are currently two types of treatments that enable someone with single ventricle heart disease to live with the disease. These two options are ‘palliative’ heart surgery and heart transplant. Both options have many risks and require one or more multiple open heart surgeries, often in very young babies and children. These treatments, while life-saving, are not cures, and they leave lifelong challenges that can alter a person’s quality of life and lifespan.
Heart Surgery
Most babies born with single ventricle heart disease have two to three open heart surgeries, starting at a few days old. The goal of these surgeries is to make sure the blood that gets pumped to the body has enough oxygen. It is important to understand that these surgeries are not considered curative.
These surgeries can include the Norwood, Glenn, and the Fontan procedures, but may also be other types of interventions like bands or shunts. The Fontan is usually carried out when the child is between two and six years old.
The goal of the Fontan is to redirect the blood flow from the lower body directly to the lungs without passing through the heart. This allows the child’s one functional ventricle to handle only oxygenated blood and pump it to the rest of the body.
The Fontan can cause many complications over time. These include problems with heart rhythm (e.g., too fast, too slow or irregular heartbeat), blood clots, liver problems (due to high pressure in the liver veins), plastic bronchitis, protein losing enteropathy, and a decline in heart function. In addition, some patients with single ventricle heart disease may experience mental health issues and neurodevelopmental impacts (difficulties or differences in how the brain processes information).
Heart Transplant
Some patients receive a heart transplant right after birth. Others may receive a heart transplant if the palliative heart surgeries are not successful, or if their heart fails after any stage of heart surgery.
Patients who receive a transplant must take medications to make sure their body does not reject the new heart. Unfortunately, transplant surgery is not always successful. Also, the medication can cause serious side effects. Things that can affect the heart transplant journey include transplant waiting list time, availability of donor hearts, and complications faced by patients while waiting for a heart and after transplant. Sometimes, patients become too sick while waiting for a transplant and are then unable to receive one. After about 10 years, the new heart may fail, meaning another transplant would be needed.
Research Roadmap for Single Ventricle Heart Disease
More research is needed
While a diagnosis of single ventricle heart disease used to mean a child would not have long to live, most patients now survive into adulthood. Unfortunately, the lack of treatments that can cure these conditions means that patients experience a range of issues that impact both their quality and duration of life. More research is needed to understand what causes single ventricle heart disease and the many related complications. With more knowledge, better treatments and even cures could be developed.
Our Research Roadmap helps us understand and map out what is needed to find better treatments and even cures for single ventricle heart disease. To create our Roadmap, we worked collaboratively with the research and clinical community.
Our four main goals, how we could achieve them, and the difference it would make for patients
In our Research Roadmap, we highlight four key areas – Origins, Outcomes, Care, and Cures – that map the pathway to a brighter future for patients with single ventricle heart disease. It is important to remember that because single ventricle heart disease is complex, there is likely no “one size fits all” solution.
Origins
Learn more about the cause
- Identify genes that cause each type of single ventricle heart disease to understand who’s at risk of the disease and to create new treatments.
- Understand how single ventricle hearts form differently than normal hearts so we can prevent or treat these defects early.
- Find out if there are other factors, like diet, exercise, and environmental exposures, that increase the risk.
Outcomes
Fully understand the complications of single ventricle
- Learn more about causes of complications, like liver or kidney disease, to develop ways to treat or prevent these issues.
- Understand why some patients don’t get these complications (known as resilience) so we can help make other patients more resilient.
- Identify if there are things we can change to decrease the risk of complications.
Care
Find ways to treat complications and, if possible, prevent them
- Find ways we can measure heart and other organ function (called biomarkers) to improve patient monitoring and help us intervene sooner to prevent complications.
- Develop drugs or medical devices that can treat complications, like liver disease.
- Test whether we can use strategies, like diet, exercise, or other methods, to prevent or treat complications.
Cures
Develop cures for patients at any age or stage
- Create new options, like a biological pump, to make a patient’s circulation normal or close to normal.
- Develop ways to prevent single ventricle heart disease by fixing the baby’s heart during pregnancy.
- Improve access to heart transplants and create better ways to match donors and recipients so we have better transplant outcomes.
There is hope on the horizon
If research is successful, a cure for single ventricle heart disease could be found and patients could live long and healthy lives.
We hope that our Research Roadmap lays the foundation for everyone in the single ventricle heart disease community and beyond to work together to advance research and bring about positive change. If this research is successful, a cure for single ventricle heart disease could be found and patients could live long and healthy lives.
Our collective call to action
Everyone in our community can help to make progress in single ventricle research and care. We invite our patients, families and caregivers, researchers, clinicians, policy makers, pharmaceutical and device companies, and funders to join with us to:
Increase funding for single ventricle research
Ensure that new discoveries are translated into clinical practice
Improve all aspects of patients’ lives, including their physical and mental health
Build a pipeline for new approved therapies for single ventricle heart disease
Create collaborative models of funding and research to spur advancement
Research Progress
Additional Ventures has committed more than $80 million and supported over 200 studies across the globe, all with the goal to advance research and clinical care, using our Research Roadmap as our guide.
We’re not alone: other groups are also funding single ventricle research, like the American Heart Association and the National Institutes of Health.