Single Ventricle Extension Study (SVR II)

Infants with single ventricle heart defects were enrolled in the Single Ventricle Reconstruction (SVR) study to look at how they did after the first stage of surgery (Norwood operation) where babies got one of two kinds of shunts: a modified Blalock-Taussig shunt (MBTS) or right ventricle to pulmonary artery shunt (RV-to-PA shunt).

In this study we wanted to learn if these same children (2-6 years of age) do better with one of the two shunts (RV-to-PA or MBTS) in the years after surgery. Also we wanted to see how other medical and surgical factors affect children's health and how they develop. Over 500 children were enrolled in this study.

Who was in the study?

All children who were enrolled in the first SVR study were invited to enroll in this study.

What happened in the study?

This study included a medical record review annually until a child reached the age of 6. Cardiac assessments were done with echocardiograms (twice during the study); ECGs and Holter monitors (at age 6); as well as a series of neurodevelopmental and quality of life questionnaires completed annually.

What were the results of the study?

Here are some of the things we’ve learned from this study:
  • Survival is better in the first year of life for children treated with a shunt from the right ventricle to the pulmonary arteries at the time of the Norwood operation. However, by three years of life, the shunt placed at the time of the Norwood operation doesn’t have much influence on the chances for survival or likelihood of needing a heart transplant.
  • Children with hypoplastic left heart syndrome and related forms of single right ventricle weighed less and were shorter than children without congenital heart disease. Children who stayed in the hospital longer after their first surgery or had a more complicated second surgery gained less weight.
  • The developmental outcomes for children in this study varied a great deal, with some children doing well and others having more difficulties. We would not easily predict the development for any individual child based on either the type of shunt placed during the Norwood procedure, hospital course, or even on developmental testing at 14 months.
We are continuing to analyze data for this study and will continue to share what we learn here. The PHN is grateful to the children and families who participated in this study.