Study identifies risk factors that increase risk of death in children with Fontan circulatory failure

A multi-center study has identified critical risk factors that increase the likelihood of death in children with a heart defect who are awaiting or have recently undergone heart transplantation, according to findings published in Circulation.

Fontan circulatory failure (FCF) is a long-term complication in children born with single-ventricle heart defects who have undergone a series of surgeries that culminates with the Fontan procedure. While this surgery helps reroute blood flow and extend life expectancy, it can lead to chronic health problems, including heart failure and damage to other organs. Many of these patients eventually require a heart transplant.

The new study, conducted across 20 U.S. medical centers, offers new insights into how specific health complications affect survival in children with the condition, said co-author Anna Joong, MD, cardiologist at Ann & Robert H. Lurie Children's Hospital of Chicago and Associate Professor of Pediatrics at Northwestern University Feinberg School of Medicine.

"We have a strong interest in understanding patients with Fontan circulatory failure: how we can better manage their heart failure, when the ideal time is to list them for a heart transplant, and what the risk factors are while waiting for a transplant," Dr. Joong said.

In the study, investigators analyzed data from 409 patients who had undergone a Fontan procedure and were listed for heart transplant between 2008 and 2022. They tracked outcomes from the time of waitlisting through one year after transplant. They found that 5.9 percent died awaiting a transplant, and among those transplanted, 8.5 percent died within the first year.

The investigators also found that certain pre-existing conditions significantly increased the risk of death, including:

• Repeated hospitalizations in the year before being listed for transplant doubled the risk of death.
• Clinical cyanosis - a condition in which oxygen levels in the blood are dangerously low - was associated with a fivefold increase in mortality risk.
• Sleep apnea, mental health conditions requiring treatment, and anatomical complications like Fontan pathway obstruction were all linked with a higher risk of death.

Overall, survival has improved for patients who have single ventricle physiology and who had a Fontan. A really novel finding of this study was that patients with low oxygen levels were associated with poor outcomes. That's an important thing for clinicians and families to know about, as an additional risk factor and when to refer to advanced heart failure therapies."

Dr. Anna Joong, MD, cardiologist at Ann & Robert H. Lurie Children's Hospital of Chicago and Associate Professor of Pediatrics at Northwestern University Feinberg School of Medicine

The findings should guide clinicians in identifying high-risk patients earlier and considering more aggressive interventions, including earlier heart failure team and transplant referral, Dr. Joong said. Overall, the study lays the groundwork for improving transplant outcomes and tailoring care to the specific needs of children born with single-ventricle heart defects.

Moving forward, Joong and her collaborators will continue to study children post-heart transplant to understand their quality of life and address any functional limitations, she said.

The study was supported by a grant from the Additional Ventures and Enduring Hearts organizations and a gift from the Van Hooser family.