SVR Study Basics

SVR is the Trial of Right Ventricular vs. Modified Blalock-Taussig Shunt (MBTS) in Infants with Single Ventricle Defect Undergoing Staged Reconstruction. The short title for the study is Single Ventricle Reconstruction (SVR). Babies born with a single ventricle heart instead of the standard two ventricles, require a series of operations to correct. The first operation, the Norwood procedure , involves placing a shunt to carry blood from the heart to the lungs. This study was done to evaluate two commonly placed shunts to see which one would improve how patients do following the Norwood procedure. The study began on May 1, 2005 and the last infant was enrolled in June 2008 with 555 babies randomized.

Who was in the study?

Babies with a single ventricle (lower pumping chamber) heart instead of 2 ventricles were in the study if a Norwood procedure was planned.

What happened during the study?

Each qualified baby was randomly assigned to one of two groups, either the MBT shunt or the PA-to-RV shunt . Babies were followed until they reached 14 months of age, had an echocardiogram and a neurodevelopmental examination and perhaps a genetic evaluation .

What were the results of the study?

Babies who received the right ventricle-to-pulmonary artery shunt had better survival, although they might have needed more unplanned heart treatments than did those who received the modified Blalock-Taussig shunt. However, when the babies were followed for longer periods of time, there was no difference between the two groups. Continued follow-up of patients in the study is very important to see if one shunt is better than the other in the long term. If your baby was in this trial, please consider enrolling in the SVR Extension study.

What we learned may or may not apply to your child. These findings are based on all 555 children who were randomized, and your child's result may be different. Please contact your cardiologist if you would like to discuss these findings in more detail.