Interstage management of pulmonary blood flow after the Norwood procedure with right ventricle-to-pulmonary artery conduit

Abstract

OBJECTIVES: Our goal was to assess the efficacy of managing pulmonary blood flow from the Norwood procedure with a right ventricle-to-pulmonary artery (RV–PA) conduit until stage 2 palliation (S2P). METHODS: Among 48 consecutive patients undergoing the Norwood procedure between 2008 and 2018, 40 (83.3%) patients who survived to discharge were included in this study. The primary diagnosis was hypoplastic left heart syndrome in 28 (70%) patients and hypoplastic left heart syndrome variant in 12 (30%) patients. All patients received bilateral pulmonary artery banding. The median age and weight at the time of the Norwood procedure were 41 (25th–75th percentiles: 27–89) days and 3.2 (2.7–3.9) kg, respectively. In keeping with institutional strategy, S2P was undertaken when body weight exceeded 5.0 kg, and normal gross motor development was confirmed. RESULTS: The RV–PA conduit was clipped in 28 (70%) patients during the perioperative period of the Norwood procedure, then partial unclipping was performed in 8 (20%) patients and full unclipping was performed in 20 (50%) patients. Before S2P, the median pulmonary-to-systemic blood flow ratio was 1.0 (0.7–1.3). The median age and weight at the time of S2P were 10.7 (9.0–12.9) months and 6.3 (5.5–7.1) kg, respectively. The survival rate 5 years after Norwood discharge was 85.3%. Pre-S2P pulmonary-to-systemic blood flow ratio was linearly correlated with greater interstage changes in systemic atrioventricular valve regurgitation (R2 = 0.223, P = 0.004). CONCLUSIONS: Interstage management of pulmonary blood flow by RV–PA conduit clipping and gradual unclipping provided good interstage outcomes. The median pulmonary-to-systemic blood flow ratio could be controlled to 1.0 at pre-S2P catheter examination.