Low Birth Weight Is Associated With Decreased Survival Following The Norwood Procedure
Ziyad M. Binsalamah, Zachary Spigel, christopher Caldarone, Dean McKenzie, Iki Adachi, Michiaki Imamura, Jeffrey Heinle.
Baylor College of Medicine, Houston, TX, USA.
Birth weight is a surrogate marker for intrauterine development commonly used to associate outcomes following congenital heart surgery. The expected survival difference for patients with low birth weight relative to normal birth weight have not been well defined following the Norwood Procedure.
We included all patients with hypoplastic left heart syndrome (HLHS) who underwent a Norwood procedure at a single institution from 1995-2018. Low birth weight was defined using World Health Organization criteria as <2500 grams. Log-rank test was used to compare survival times between cohorts and multivariate Cox regression analysis was used to evaluate associations with survival.
326 neonates (60% male) underwent the Norwood procedure and were followed for a median 3.5 years (IQR 0.4 - 10.3). Low birth weight was observed in 35 (11%). Compared to neonates with normal birth weights, low birth weight neonates were more likely to receive a Sano shunt (43% vs 22%, p = 0.01). Actuarial survival was 59%, 45%, and 45% for low birth weight neonates and 72%, 66%, and 66% for normal weight neonates at 1, 5, and 10 years. In a multivariate model controlling for syndromic status, shunt type, initial tricuspid regurgitation, and tricuspid valvuloplasty at the time of the Norwood, low birth was associated with decreased survival relative to normal birth weight (HR 1.8, 95%CI 1.0 - 3.0, p=0.038).
Low birth weight neonates with HLHS undergoing the Norwood procedure have increased early mortality relative to normal birth weight neonates, however the difference plateaus after Fontan palliation.