Impact of low birth weight on staged single-ventricle palliation

Background: To assess the impact of low birth weight on early and late outcomes after staged palliation for single ventricle. Methods: Patients after stage 1 palliation for single ventricle in our institution were retrospectively included and divided into two weight groups: 2.5 kg or less (low birth weight) and more than 2.5 kg. The impact of low birth weight on mortality and on the progression to further palliation stages (bidirectional Glenn, stage 2, and total cavopulmonary connection, stage 3) was assessed. Results: A total of 452 patients were included. Patients with low birth weight (n = 37, 8 %) had more frequently associated prematurity and extracardiac anomalies. Early and inter-stage mortality after stage 1 was higher in patients with low birth weight, so that less of these patients reached the next palliation stage (57 % vs. 77 %, p = 0.01, and 38 % vs. 56 %, p = 0.05, for stage 2 and stage 3, respectively). After 5 years, overall survival was inferior in patients with low birth weight (48 % vs. 73 %, p < 0.001). Survival conditioned by stage 2 palliation was inferior in patients with low birth weight compared to the reference group (76 % vs. 89 % after 5 years, p = 0.04). Low birth weight was a risk factor for death in most patients' subgroups, inclusive those with restricted pulmonary blood flow after a systemic-to-pulmonary shunt procedure. Conclusions: During staged palliation of single-ventricle physiology, low birth weight has a detrimental impact on survival extending to beyond stage 2. This study calls for increased vigilance of these patients beyond the first interstage.