Risk factors for mortality after the Norwood procedure

Abstract

Objectives: Recent studies have suggested that survival following the Norwood procedure is influenced by anatomy and is worse for patients with hypoplastic left heart syndrome (HLHS), particularly aortic atresia (AA), as compared to other forms of functional single ventricle and systemic outflow tract obstruction. The current study was undertaken to evaluate our recent experience with the Norwood procedure and to evaluate potential predictors of operative and 1-year mortality. Methods: A retrospective study of risk factors for operative and 1-year mortality in 158 patients undergoing the Norwood procedure between January 1, 1998 and June 30, 2001. Results: HLHS was present in 102 patients (70 with AA) and other forms of functional single ventricle with systemic outflow tract obstruction in the remaining 56. Operative survival was 77% (122/158), 78% for patients with HLHS and 75% for patients with other diagnoses. Multivariable analysis identified birth weight (odds ratio (OR) 0.18/kg, 95% confidence limit (CL) 0.08–0.42, P≪0.001), associated cardiac anomalies (OR 4.45, 95% CL 1.50–13.2, P=0.001), total support time (OR 1.02/min, 95% CL 1.01–1.03, P=0.004), and extracorporeal membrane oxygenation (ECMO) or ventricular assist device (VAD) support (OR 17.8, 95% CL 4.40–71.0, P≪0.001) as predictors of operative mortality. The anatomic diagnosis (HLHS versus non-HLHS) was not a predictor of mortality, P=0.6). The Kaplan–Meier survival estimate at 1 year was 66% (95% CL 58–73%) and was not different for patients with HLHS compared to non-HLHS, P=0.5. For patients who have survived the Norwood procedure, survival to 1 year was 86% (95% CL 78–91%). Presence of an extra-cardiac anomaly or genetic syndrome (OR 2.70, 95% CL 0.98–7.41%, P=0.05) and presence of an additional cardiac defect (OR 3.99, 95% CL 1.67–9.57, P=0.002) were predictors of worse survival in the first year of life. Conclusions: The Norwood procedure is currently being applied to a heterogeneous group of patients. Operative and 1-year survival are equivalent for patients with HLHS and those with other cardiac defects. The presence of additional cardiac or extra-cardiac anomalies are predictors of poor outcome.