Abstract 1815: Outcomes of the Norwood Operation in Infants Randomized to a Modified Blalock-Taussig versus Right Ventricle-to-Pulmonary Artery Shunt: The Pediatric Heart Network Single Ventricle Reconstruction Trial
Background. The Norwood procedure with a modified Blalock-Taussig shunt (MBTS) is widely used for the Stage I palliation of single ventricle lesions, but mortality remains high. An alternative conduit to the MBTS, the right ventricle-to-pulmonary artery shunt (RVPAS), eliminates aortic diastolic run-off and coronary arterial steal, but requires a right ventriculotomy. The effectiveness and safety of these two techniques have not previously been compared in a randomized trial.
Methods. Newborns with a single right ventricle (RV) lesion were recruited at 15 North American centers through the Pediatric Heart Network. Subjects were randomized to receive a MBTS or RVPAS, with stratification by presence vs. absence of aortic atresia and obstructed pulmonary venous return. The primary endpoint was the rate of death or cardiac transplantation 12 months after randomization. Secondary outcomes included measures of morbidity at the Norwood and stage II procedures, RV function and pulmonary artery growth, and neurodevelopment.
Results. From 5/2005–7/2008, 921 newborn infants with a single ventricle were screened; 664 were eligible and 555 were randomized. There were no differences in baseline characteristics between consenting and non-consenting eligible patients or by assigned shunt type. The randomized cohort was 61% male and 73% Caucasian; 87% had HLHS, 62% had aortic atresia and 3.6% had obstructed pulmonary venous return. Mean birth weight was 3.1±0.5 kg and 25% of subjects were of gestational age <38 weeks. Trial measurements will be completed by September 2009. Results comparing the two shunts with regard to 12-month death or transplantation, as well as selected secondary outcomes, will be presented.
Conclusions. This is the first North American multi-institutional, randomized surgical trial in a congenital heart disease population. The results will help in developing evidence-based surgical approaches aimed at improving outcomes in this high risk cohort. This collaborative effort will also serve as a model for assessing future novel operative interventions in pediatric heart disease patients.