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.