Single Ventricle Reconstruction Follow-Up 2 (SVR II)

(Observational Study)

Study Summary

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.

Over 500 Participants

Were enrolled in this follow-up study.

5 Years of Follow-Up

Patients were followed from 14 months until age 6, for a total of 5 years of follow-up.

Inconclusive Findings

Developmental outcomes for children in this study varied a great deal.

Who was in the study?

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

What happened during 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.

The PHN is grateful to the children and families who participated in this study. See the SVR III study for more information about further follow-up of these families.

Study Publications

  • Transplantation-free survival and interventions at 3 years in the single ventricle reconstruction trial

    J. Newburger, Circulation 2014; 129:2013-2020.

    In the Single Ventricle Reconstruction (SVR) trial, 1-year transplant-free survival was better for the Norwood procedure with right ventricle-to-pulmonary artery shunt (RVPAS) compared with a modified Blalock-Taussig shunt (MBTS). At 3 years, we compared transplantation-free survival, echocardiographic right ventricular ejection fraction, and unplanned interventions in the treatment groups. By 3 years, the Norwood procedure with RVPAS compared with MBTS was no longer associated with better transplant-free survival. Moreover, RVPAS subjects had slightly worse right ventricular ejection fraction and underwent more catheter interventions.

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  • Factors associated with neurodevelopment for children with single ventricle lesions

    C. Goldberg, J Pediatr 2014; 165(3): 490-496.

    This study measured neurodevelopment at 3 years of age and compared it to neurodevelopment at 14 months of age in children enrolled in the Single Ventricle Reconstruction trial. Scores on tests to evaluate neurodevelopment were lower at 3 years of age when compared to a normal population. The results suggest that even when 14-month scores are within the normal range, children with single ventricle heart defects may be at risk for developmental impairment at pre-school age and beyond. Therefore, all children with HLHS and related single ventricle malformations should be followed longitudinally to improve recognition of delays and potential for intervention.

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  • Longitudinal assessment of growth in hypoplastic left heart syndrome: results from the single ventricle reconstruction trial

    P. Burch, J Am Heart Assoc 2014; 3(3):e000079.

    Poor growth is associated with poor prognosis in several disease processes. While children with single ventricle heart disease are known to be smaller than their peers at birth, there is limited information regarding growth and development in survivors. In this paper we show that single ventricle survivors continue to grow poorly with regards to both height and weight through the first two surgical palliations and at three years of age.

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  • Impact of Initial Shunt Type on Cardiac Size and Function in Children with Single Right Ventricle Anomalies prior to the Fontan Procedure—The Single Ventricle Reconstruction Extension Trial

    P. Frommelt, J Am Coll Cardiol 2014; 64(19):2026-35.

    The initial shunt type at the Norwood procedure used to supply blood flow to the lungs in infants with single right ventricle anomalies may influence heart muscle function during the second and third years of life. This study tested heart muscle function in children in the SVR trial, comparing those who had a right ventricle-to-pulmonary artery shunt versus the modified Blalock-Taussig shunt. While there were no differences between the groups, a markedly enlarged heart, poor heart muscle function, and significant heart valve enlargement/dysfunction at 14 months of age was associated with poorer survival to the Fontan operation.

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  • Factors affecting Fontan length of stay: Results from the Single Ventricle Reconstruction trial

    C. Ravishankar, J Thorac Cardiovasc Surg. 2016; 151(3):669-675.

    In the Single Ventricle Reconstruction trial, infants with hypoplastic left heart syndrome (HLHS) who received a right-ventricle-to-pulmonary-artery shunt (RVPAS) versus a modified Blalock-Taussig shunt (MBTS) had lower early postoperative mortality, but more complications at 14 months. This study explored the effect of shunt type and other patient, medical, and surgical factors on postoperative length of stay (LOS) after the Fontan operation. The type of shunt received at the Norwood surgery did not affect how long a baby stayed in the hospital for the Fontan surgery. Rather, more medical complications before the operation resulted in longer LOS after the Fontan operation.

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  • Variation in care for children undergoing the Fontan operation for hypoplastic left heart syndrome

    A. W. Eckhauser, Cardiol Young. 2019 Dec;29(12):1510-1516.

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  • Norwood Shunt Type is Not Predictive of Arrhythmias at 6-years: Analysis from the Single Ventricle Reconstruction Trial

    N. Cain, Journal of the American College of Cardiology 2022; 169:107-112.

    This study compared the effect of both shunt type and Fontan type on the incidence of abnormal heart rhythms (arrhythmias) by 6 years of age in the Pediatric Heart Network Single Ventricle Reconstruction Extension Study (SVRII). By 6 years of age, benign ventricular beats were common in the SVR II population, and it was common for participants to be on medication to treat abnormal heart rhythms, but most of those medications also support heart function. Of the 7 patients with death or transplant between 2-6 years, none had ventricular arrhythmias, but compared with transplant-free survivors, they had some differences in ECG measurements (a longer QRS and a trend toward a longer QTc interval). Fast arrhythmias that begin in the top chambers of the heart (atrial tachyarrhythmias) varied by Fontan type, but not by shunt type. We concluded that, despite the potential for increased risk of ventricular arrhythmias and sudden death in the RV to PA shunt group, the data from the SVR and SVRII studies do not show any significant differences by shunt type or increased risk by 6 years of follow-up. The findings support the need for ongoing surveillance for arrhythmias in the SVR population.

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  • The Relationship of Family Factors to Psychosocial Outcomes in Children with Hypoplastic Left Heart Syndrome at 6 Years of Age

    K. A. Mussatto, The Journal of Pediatrics 2023; 255:50-57.

    Hypoplastic left heart syndrome (HLHS) has a significant impact on both children and families. The purpose of this study was to gain an understanding of how family factors (parent mental health, quality of life, family resources, function and family management of condition) are associated with psychosocial outcomes in children with HLHS at 6 years of age. Parent mental health, quality of life, family resources and family function had no significant relationships to child psychosocial outcomes. Parent perceptions that their child had a normal life despite their heart condition, that the condition was manageable and had a lower impact on family daily life were associated with better child adaptive behavior, adaptive skills and fewer internalizing behavior problems (depression, anxiety, somatic complaints). Improved understanding of the associations between family factors and child outcomes should guide counseling and the development of tailored interventions to capitalize on each family’s strengths.

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