Outcomes of cardiac surgery in patients weighing <2.5 kg: affect of patient-dependent and -independent variables

Abstract

Objective: A recent Society of Thoracic Surgeons database study showed that low weight (<2.5 kg) at surgery was associated with high operative mortality (16%). We sought to assess the outcomes after cardiac repair in patients weighing <2.5 kg versus 2.5 to 4.5 kg in an institution with a dedicated neonatal cardiac program and to determine the potential role played by prematurity, the Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery (STAT) risk categories, uni/biventricular pathway, and surgical timing.

Methods: We analyzed the outcomes (hospital mortality, early reintervention, postoperative length of stay, mortality [at the last follow-up point]) in patients weighing <2.5 kg at surgery (n = 146; group 1) and 2.5 to 4.5 kg (n = 622; group 2), who had undergone open or closed cardiac repairs from January 2006 to December 2012 at our institution. The statistical analysis was stratified by prematurity, STAT risk category, uni/biventricular pathway, and usual versus delayed surgical timing. Univariate versus multivariate risk analysis was performed. The mean follow-up was 21.6 ± 25.6 months.

Results: Hospital mortality in group 1 was 10.9% (n = 16) versus 4.8% (n = 30) in group 2 (P = .007). The postoperative length of stay and early unplanned reintervention rate were similar between the 2 groups. Late mortality in group 1 was 0.7% (n = 1). In group 1, early outcomes were independent of the STAT risk category, uni/biventricular pathway, or surgical timing compared with group 2. A lower gestational age at birth was an independent risk factor for early mortality in group 1.

Conclusions: A dedicated multidisciplinary neonatal cardiac program can yield good outcomes for neonates and infants weighing <2.5 kg independently of the STAT risk category and uni/biventricular pathway. A lower gestational age at birth was an independent risk factor for hospital mortality.