Is a hybrid strategy a lower-risk alternative to stage 1 Norwood operation?

J Thorac Cardiovasc Surg. 2017 Jan;153(1):163-172.e6. doi: 10.1016/j.jtcvs.2016.08.021. Epub 2016 Aug 31.


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.

Keywords: Norwood; congenital heart disease; critical left ventricular outflow tract obstruction; hybrid; hypoplastic left heart syndrome; single ventricle.

Publication types

  • Multicenter Study
  • Observational Study

MeSH terms

  • Age Factors
  • Birth Weight
  • Blalock-Taussig Procedure* / adverse effects
  • Blalock-Taussig Procedure* / mortality
  • Canada
  • Female
  • Fontan Procedure
  • Heart Defects, Congenital / diagnostic imaging
  • Heart Defects, Congenital / mortality
  • Heart Defects, Congenital / physiopathology
  • Heart Defects, Congenital / surgery*
  • Heart Transplantation
  • Humans
  • Infant, Newborn
  • Male
  • Norwood Procedures* / adverse effects
  • Norwood Procedures* / mortality
  • Palliative Care
  • Prospective Studies
  • Recovery of Function
  • Risk Factors
  • Time Factors
  • Treatment Outcome
  • United States
  • Ventricular Outflow Obstruction / diagnostic imaging
  • Ventricular Outflow Obstruction / mortality
  • Ventricular Outflow Obstruction / physiopathology
  • Ventricular Outflow Obstruction / surgery*