Cardiac surgery in low birth weight infants: current outcomes

Low birth weight (LBW) is a risk factor for mortality in neonatal and infant heart surgery. The purpose of this study was to determine the contemporary outcomes and risk factors of cardiac surgery in low weight babies. The records of 75 consecutive infants weighing <2.5 kg having heart surgery were reviewed. The median weight was 2100 g (range 800-2500 g) and median age was 11 days (range 2-86 days). Half (n=38) of the infants were premature. Diagnoses included: arch obstruction (n=14), hypoplastic left heart syndrome (HLHS) (n=12), tetralogy of Fallot (ToF) or pulmonary atresia (PA)/ventricular septal defect (VSD) (n=11), transposition of the great arteries (TGA) (n=7), total anomalous pulmonary venous return (TAPVR) (n=5), and other (n=20). There were two early deaths. Follow-up was available on all infants with a median duration of 1320 days (range 6-3055 days). Cumulative Kaplan-Meier survival at one year was 90% [95% confidence interval (CI), 80-95%] and at five years was 88% (95% CI, 77-94%). Overall mortality amongst patients with genetic/chromosomal abnormalities was higher, 28% vs. 5.4% amongst patients without such abnormalities (P=0.008). Age, prematurity, preoperative mechanical ventilation, prostaglandins, non-cardiac organ dysfunction, extra-cardiac malformations, perioperative extracorporeal membrane oxygenation (ECMO), and type of procedure were not associated with significant differences in mortality. Cardiac surgery in LBW infants can be performed with low early and mid-term mortality. LBW infants with chromosomal/genetic anomalies have a higher risk.