Comparison of in-hospital and longer-term outcomes of hybrid and Norwood stage 1 palliation of hypoplastic left heart syndrome

Objectives: The hybrid approach for the initial management of hypoplastic left heart syndrome shifts the risks of major open surgery from the vulnerable neonatal period to an older age. This study determined differences between the hybrid and the standard Norwood procedures in postoperative in-hospital mortality, renal failure, and survival to at least 2 years of age. Methods: Data from the Pediatric Health Information System, a detailed hospital discharge database of 43 freestanding children's hospitals, were analyzed. The Pediatric Health Information System includes demographic information, diagnosis, and procedure and clinical service data. Instrumental variable regression techniques were used to estimate the predicted probability of in-hospital mortality, renal failure, and survival to 24 months of age for infants with hypoplastic left heart syndrome who received a hybrid or Norwood procedure. The statistical models controlled for demographics and comorbid chromosomal anomalies. Results: A total of 3654 infants with hypoplastic left heart syndrome underwent intervention from 1998 to 2012. Of these, 242 underwent the hybrid approach and the remainder underwent the Norwood procedure. Instrumental variable models showed significantly reduced odds of patients who underwent the hybrid approach being diagnosed with renal failure (adjusted risk ratio [ARR], 0.48; 95% confidence interval [CI], 0.26-0.89); increased odds of surviving initial hospitalization (ARR, 1.28; 95% CI, 1.06-1.55); increased odds of survival, indicated by readmissions more than 6 months after initial hospitalization (ARR, 1.53; 95% CI, 1.05-2.22); and a decrease in length of stay by 20 days for the initial surgical hospitalization (95% CI, -27.4 to -13.9). Conclusions: The short term hospital-based outcomes and longer-term survival outcomes of the hybrid approach for hypoplastic left heart syndrome may be better than those of the Norwood procedure.