Preoperative risk factors influencing inter-stage mortality after the Norwood procedure

OBJECTIVES With improvements in early survival after the stage I palliation (S1P) Norwood procedure for hypoplastic left heart syndrome (HLHS) and its variants, inter-stage death accounts for an increasing proportion of mortality. Our aim was to identify the risk factors for inter-stage mortality. METHODS The records of 322 neonates with HLHS or a variant who underwent the Norwood procedure at our centre between 2001 and 2019 were retrospectively analysed. RESULTS The diagnoses included 271 neonates with HLHS (84%) and 51 with variants (16%). Aortic atresia was observed in 138 (43%) patients, mitral atresia in 91 (28%), extracardiac anomalies in 42 (13%) and genetic disorder in 14 (4%). The median age and weight of the patients at the S1P Norwood procedure were 9 (interquartile range: 7–12) days and 3.2 (2.9–3.5) kg, respectively. The median cardiopulmonary bypass time was 137 (107–163) min. Modified Blalock–Taussig shunts were used in 159 (49%) and unvalved right ventricle-to-pulmonary artery shunts in 163 (51%) patients. The number of inter-stage deaths was as follows: between S1P and stage II palliation (S2P), 61 including 38 early (30 days) deaths, and between S2P and stage III palliation, 32 deaths. Low birth weight ( CONCLUSIONS The risk factors for inter-stage attrition after the Norwood procedure were different between each stage. Preoperative factors, including birth weight, restrictive atrial septum and extracardiac anomalies, adversely affected the inter-stage mortality.