Older children at the time of the Norwood operation have ongoing mortality vulnerability that continues after cavopulmonary connection

Objectives Delayed first-stage palliation of children with hypoplastic left heart syndrome and related pathologies can be associated with poor outcomes because of development of progressive pulmonary vascular disease and volume load effects on the systemic ventricle and atrioventricular valve. We examine the current era’s survival in this subgroup. Methods Fifty-five infants older than 2 weeks underwent the Norwood operation (2003–2007). Separate competing risk analyses were performed to model outcomes (death and transition to the next stage) after the Norwood operation and after bidirectional cavopulmonary connection. Results Median age was 32 days (range, 15–118 days). Forty-seven percent had hypoplastic left heart syndrome, and 53% had other complex univentricular variants. Mean ascending aortic size was 4.4 ± 1.9 mm, 10% had impaired ventricular function, 11% had moderate atrioventricular valve regurgitation, and 32% had restrictive pulmonary venous return. Pulmonary blood flow was established through an aortopulmonary shunt (n = 30) or Sano shunt (n = 25). After the Norwood operation, patients required longer ventilation and more oxygen and nitric oxide and had higher inotropic scores compared with those undergoing the traditional management protocol. Competing risks analysis showed that 2 years after the Norwood operation, 39% had died, and 57% underwent bidirectional cavopulmonary connection. Four years after bidirectional cavopulmonary connection, 15% had died, and 85% underwent the Fontan operation. Overall 3-year survival after the Norwood operation was 53%. Factors associated with mortality were age, lower weight at the time of the Norwood operation, impaired ventricular function, longer circulatory arrest, and lower pre–bidirectional cavopulmonary connection saturation. Conclusions Children older than 2 weeks undergoing the Norwood operation frequently require postoperative pulmonary vasodilatation and high inotropic support. A significant hazard of death persists through all steps of multistage palliation. Increased pulmonary vascular resistance and volume load effects, such as systemic ventricular impairment and atrioventricular valve regurgitation, are commonly evident in patients in whom treatment fails or who do not qualify to proceed to the next stage of palliation. Those patients should be closely monitored for timely referral for heart transplantation when indicated.