Cardiac Surgery with Cardiopulmonary Bypass in Low-Weight or Preterm Neonates: A Retrospective Study Analyzing Early Outcome

Background: Most outcome studies in congenital cardiac surgery for "low weight" neonates include patients undergoing surgery without cardiopulmonary bypass (CPB). The primary objective of our study was to identify risk factors for in-hospital mortality in neonates weighing less than 3 Kg and undergoing surgery with CPB. In addition, we compared the effect of early surgery with CPB (before 37W-gestational age (GA)) for congenital heart disease to delayed surgery until a corrected GA of 37 weeks in an attempt to promote weight gain. Methods: Retrospective single-center study including all patients operated between 1997 and 2017. Uni-and multivariable analysis were used to analyze outcome. Results: 143 patients were included. The median weight was 2.7 Kg and 49 (34.3%) weighted <2.5 Kg. 80% of the patients were Risk stratification STAT categories >= 3. 114 patients (80%) were operated without delay (usual timing, median age 9 days), whereas 29 patients (20%) entered a delayed strat-egy (median age 30 days). In-hospital mortality was 21.7%. By multivariate analysis, dysmaturity, preoperative positive ventilation, post-operative ECMO requirement or resuscitation, and any residual lesion were predictors of in-hospital death. In-hospital mortality in the usual timing group and the delayed group were 21.1% and 24.1%, respectively (p = 0.71). In-hospital mortality for neonates operated prior to 37W-GA (n = 10) was 27.3%. Conclusions: Predictors of in-hospital mortality in neonates less 3 Kg requiring CPB surgery did not differ from those unveiled in other contemporary studies. Our data demonstrates that a strategy of delaying surgery in selected patients resulted in similar clinical outcome.