Background

Previous studies suggest that birth before 39 weeks' gestational age (GA) is associated with higher perioperative mortality and morbidity after congenital heart surgery. The optimal approach to timing of cardiac operation in premature infants remains unclear. We investigated the impact of GA at birth and corrected GA at surgery on postoperative outcomes using the Pediatric Cardiac Critical Care Consortium (PC⁴) database.

Methods

Infants undergoing selected index cardiac operations before the end of the neonatal period were included (n = 2298). GA at birth and corrected GA at the time of the index cardiac operation were used as categorical predictors and fitted as a cubic spline to assess nonlinear relationships. The primary outcome was hospital mortality. Multivariable logistic regression models assessed the association between predictors and outcomes while adjusting for confounders.

Results

Late-preterm (34-36 weeks) birth was associated with increased odds of mortality compared with full-term (39-40 weeks) birth, while early-term (37-38 weeks) birth was not associated with increased mortality. Corrected GA at surgery of 34 to 37 weeks compared with 40 to 44 weeks was associated with increased mortality. When analyzing corrected GA at surgery as a continuous predictor of outcome, odds of survival improve as patients approach 39 weeks corrected GA.

Conclusions

Contrary to previous literature, we did not find an association between early-term birth and hospital mortality at PC⁴ hospitals. Our analysis of the relationship between corrected GA and mortality suggests that operating closer to full-term corrected GA may improve survival.