Congenital: Hypoplastic left heart syndrome
Is a hybrid strategy a lower-risk alternative to stage 1 Norwood operation?

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Abstract

Background

For neonates with critical left ventricular outflow tract obstruction (LVOTO), hybrid procedures are an alternative to the Norwood stage 1 procedure. Despite perceived advantages, however, outcomes are not well defined. Therefore, we compared outcomes after stage 1 hybrid and Norwood procedures.

Methods

In a critical LVOTO inception cohort (2005-2014; 20 institutions), a total of 564 neonates underwent stage 1 palliation with the Norwood operation with a modified Blalock-Taussig shunt (NW-BT; n = 232; 41%), Norwood operation with a right ventricle–to–pulmonary artery conduit (NW-RVPA; n = 222; 39%), or a hybrid procedure (n = 110; 20%). Post–stage 1 outcomes were analyzed via competing-risks and parametric hazard analyses and compared among all 564 patients and between patients who underwent propensity-matched hybrid and those who underwent NW-BT/NW-RVPA.

Results

By 6 years after the stage 1 operation, 50% ± 3%, 7% ± 2%, and 4% ± 1% of patients transitioned to Fontan, transplantation, and biventricular repair, respectively, whereas 7% ± 2% were alive without transition and 32% ± 2% died. Risk factors for death without transition included procedure type, smaller ascending aorta, aortic valve atresia, and lower birth weight. Risk-adjusted 4-year survival was better after NW-RVPA than after NW-BT or hybrid (76% vs 60% vs 61%; P < .001). Furthermore, for neonates with lower birth weight (<∼2 kg), an interaction between birth weight and hybrid resulted in a trend toward better survival after hybrid compared with NW-BT or NW-RVPA. For propensity-matched neonates between hybrid and NW-BT (88 pairs), 4-year survival was similar (62% vs 57%; P = .58). For propensity-matched neonates between hybrid and NW-RVPA (81 pairs), 4-year survival was better after NW-RVPA (59% vs 75%; P = .008).

Conclusions

For neonates with critical LVOTO undergoing single-ventricle palliation, NW-RVPA was associated with the best overall survival. Hybrid strategies are not a lower-risk alternative to Norwood operations overall; however, the impact of lower birth weight on survival may be mitigated after hybrid procedures compared with Norwood operations.

Key Words

congenital heart disease
single ventricle
critical left ventricular outflow tract obstruction
hypoplastic left heart syndrome
hybrid
Norwood

Abbreviations and Acronyms

BSA
body surface area
CHSS
Congenital Heart Surgeons' Society
CPB
cardiopulmonary bypass
DHCA
deep hypothermic circulatory arrest
KM
Kaplan-Meier
LVOTO
left ventricular outflow tract obstruction
NW-BT
Norwood with modified Blalock-Taussig shunt
NW-RVPA
Norwood with right ventricle–pulmonary artery conduit

Cited by (0)

This study was funded by the Congenital Heart Surgeons' Society and the Department of Cardiovascular Surgery, The Hospital for Sick Children.