Abstract
BACKGROUND: In the Single Ventricle Reconstruction (SVR) trial, 1-year transplant-free survival favored the right ventricle-to-pulmonary artery shunt (RVPAS) over the modified Blalock-Taussig-Thomas shunt. However, this benefit diminished over time, and long-term shunt-type comparisons were complicated by the differing morbidity profiles of the 2 shunts. OBJECTIVES: Our objective was to better assess SVR trial global morbidity and longitudinal outcomes by using a novel hierarchically ranked composite endpoint. METHODS: A multi-institutional committee developed the endpoint incorporating death, transplant, parent-reported adaptive function and quality of life, right ventricular function, major complications, and hospital stay. Participants were ranked by their worst outcome over 16 years of follow-up. Outcomes were compared by shunt type using risk-adjusted ordinal logistic regression, with Kaplan-Meier, Cox regression, and win ratio analyses for sensitivity. RESULTS: Death or major morbidity occurred in 87% of SVR trial participants (480/549). Multivariable analysis identified interaction (P = 0.01) between shunt type and pre-Norwood tricuspid regurgitation with no shunt-related difference in outcomes in those with no or mild pre-Norwood tricuspid regurgitation (OR: 1.3; 95% CI: 0.9-1.8; P = 0.14) but worse outcomes in RVPAS participants with moderate or severe pre-Norwood tricuspid regurgitation (OR: 0.4; 95% CI: 0.2-0.9; P = 0.03). Sensitivity analyses confirmed these findings, with Cox regression showing increased mortality in RVPAS participants with moderate or severe pre-Norwood tricuspid regurgitation (HR: 5.4; 95% CI: 2.2-13.1; P = 0.0002). Prematurity and site were significant independent predictors of worse outcomes. CONCLUSIONS: Few patients with single ventricles survive free of major morbidity. Although overall outcomes did not differ by shunt type, the observed interaction between shunt type and severity of tricuspid regurgitation highlights an important area for future investigation. (Comparison of Two Types of Shunts in Infants With Single Ventricle Defect Undergoing Staged Reconstruction-Pediatric Heart Network; NCT00115934).