Stage I palliation for hypoplastic left heart syndrome in low birth weight neonates: Can we justify it?

Objective: Although the outcome of cardiac surgery in neonates with low birth weight (LBW) has improved, LBW remains a risk factor for surgical palliation. Few surgical series of LBW patients include those with hypoplastic left heart syndrome (HLHS). To identify variables associated with poor outcome in this group, we reviewed our experience with patients with HLHS and LBW who underwent Stage I Norwood palliation. Methods: Between January 1998 and December 2000, 20 consecutive LBW (<2500g) neonates with HLHS (n=13) or HLHS variant (n=7) underwent surgical palliation. Retrospective review of all patient data and analysis to identify risk factors was performed. Results: Mean age at surgery was 5.1±4.6 days (range 1-17), mean weight was 1.98±0.44kg (range 1.1-2.5), including nine patients under 2kg. Ten patients were born at <35 weeks gestation. Anatomic diagnosis included HLHS in 13 patients (10 with aortic atresia), unbalanced atrioventricular canal defect in two, double outlet right ventricle in two and other variants in three. Mean ascending aortic size was 4.0±1.8mm (range 1.5-8). Associated cardiac defects were present in three patients, and a genetic syndrome and/or congenital anomaly was present in four of them. Mean circulatory arrest time was 60±10min. Extracorporeal support was used perioperatively in 10 patients. Early mortality was 9/20 (45%). At a mean follow up at 22±10 months (range 8-38), six patients underwent stage II, and are awaiting stage III; four patients have completed their Fontan. Anatomic variant, ascending aortic size, prematurity, age at surgery, weight, duration of circulatory arrest, cardiopulmonary bypass time and associated non-cardiac anomalies were not risk factors for poor outcome whereas restrictive pulmonary venous drainage and coronary artery anomalies were associated with decreased survival. Conclusion: LBW newborns with HLHS and physiologic variants have an increased early surgical risk but have acceptable intermediate survival rates for subsequent palliation including Fontan. LBW and prematurity should not be contraindications to early surgical palliation.