Single Ventricle Palliation in Low Weight Patients Is Associated With Worse Early And Midterm Outcomes

Background. While low weight is an established risk factor for operative mortality after single ventricle (SV) palliation, its influence on late outcomes is not well understood. We examined current-era effects of low weight at time of surgery on hospital mortality, progression through palliative stages, and survival. Methods. Five hundred and thirty infants with SV underwent first-stage palliation (2002 to 2012). Competing risk analysis modeled events after initial surgery and after Glenn. Regression models examined the effect of low weight 2.5 kg or less (n = 77 of 530, 14.5%) on early and late outcomes. Results. Initial palliation was Norwood (n = 284, 54%), modified Blalock-Taussig shunt (n = 173, 33%), and pulmonary artery band (n = 73, 14%). Competing risk analysis showed that at 6 months after initial palliation the proportion of patients who had died or received transplantation was 40% in patients 2.5 kg or less and 20% in patients greater than 2.5 kg (p < 0.001). Consequently, the proportion of patients who had progressed to Glenn was 33% in patients 2.5 kg or less and 59% in patients greater than 2.5 kg (p < 0.001). Subsequent to Glenn, progression toward Fontan was unaffected by initial weight. In addition to increased hospital mortality (odds ratio 1.86, 95% confidence interval = CI] 0.93% to 3.70%, p = 0.08); adjusted hazard analysis showed that weight 2.5 kg or less was associated with diminished late survival (hazard ratio 1.65, 95% CI 1.085% to 2.53%, p = 0.02) and that was evident for all palliation types and most SV morphologies. Conclusions. Low weight at time of first-stage SV palliation is associated with an increase in both hospital mortality and interstage attrition, with subsequently fewer patients progressing toward the Glenn operation. The increased death hazard in low weight SV patients persists for almost 1 year after initial palliation, suggesting the need for more vigilant monitoring and outpatient care in those high-risk patients. (C) 2015 by The Society of Thoracic Surgeons