Experience with the Norwood operation for hypoplastic left heart syndrome

Introduction and objectives. To describe our experience and to identify risk factors for in-hospital mortality. Methods. Between October 1991 and June 2005, 42 children underwent the Norwood procedure. In the first 30 patients, pulmonary circulation was established using a modified Blalock-Taussig shunt (Group 1), while a right ventricle to pulmonary artery conduit was used in the remaining 12 (Group 2). Preoperative anatomic features and procedural factors were analyzed with respect to their impact on mortality. Postoperatively, data were collected on arterial blood pressure, arterial and venous oxygen saturation, arterial pH, venous pCO(2), the PaO2/FiO(2) ratio, tissue oxygen extraction, and dead space fraction. The association between each individual variable and mortality was investigated. Results. Thirty patients (71.4 %) had both aortic and mitral atresia, eight (19 %) had either aortic or mitral atresia, and four (9.5%) had no valvular atresia. There was no statistically significant difference in postoperative mortality between the groups 1 and 2 (12/22 [54.5 %] vs 7/12 [58.3 %]; P = .56). The only significant risk factor for in-hospital mortality was a longer cardiopulmonary bypass time (P = .01) and, for intraoperative mortality, primary rather than delayed sternal closure (P = .004). Venous pCO(2), the mean dead space fraction, and tissue oxygen extraction all tended to be higher among infants who died, but the difference was not statistically significant. Conclusions. Use of a right ventricle to pulmonary artery conduit did not improve postoperative survival. Both a long cardiopulmonary bypass time and primary sternal closure were associated with increased mortality.