Impact of right ventricle to pulmonary artery conduit on outcome of the modified norwood procedure

Background To determine and compare outcome of the modified Norwood procedure using either a systemic to pulmonary artery (SPA) shunt or right ventricle to pulmonary artery (RV-PA) conduit in a consecutive series of neonates at a single institution. Methods The medical records were retrospectively examined for preoperative demographic and echocardiographic data, operative variables, and postoperative clinical and hemodynamic data. From November 2001 to March 2003, 21 neonates had a modified Norwood procedure (SPA shunt, N = 8; RV-PA conduit, N = 13) at a median age of 5 days (range 1 to 18 days) and a median weight of 2.9 kg (range 1.7 to 4.1 kg). Of the 21 infants, 12 were considered high risk due to presence of low birth weight (n = 4), extracardiac or genetic anomalies (n = 5) or obstruction to pulmonary venous return (n = 5). Nine “high risk” infants were in the RV-PA conduit group. Results Overall Norwood operation survival was 90% (19/21) and did not differ between groups. There were 2/19 interstage deaths and Kaplan-Meier survival at 1 year is 79%. Neonates in the RV-PA conduit group had significantly higher diastolic blood pressures at 1, 6, and 24 hours postoperatively (p< 0.05). Neonates in the SPA shunt group had significantly higher heart rates at 1 hour postoperatively (p< 0.05) than those in the RV-PA group. There was a trend to higher number of ventilatory interventions to balance Qp:Qs in the SPA shunt group (p = 0.06). Conclusions In a relatively high-risk group, neonates having an RV-PA conduit as part of the Norwood procedure have favorable postoperative hemodynamics and a good likelihood of stage I survival.