Risk factors for hospital morbidity and mortality after the Norwood procedure: A report from the Pediatric Heart Network Single Ventricle Reconstruction trial

Abstract

Objectives: We sought to identify risk factors for mortality and morbidity during the Norwood hospitalization in newborn infants with hypoplastic left heart syndrome and other single right ventricle anomalies enrolled in the Single Ventricle Reconstruction trial.

Methods: Potential predictors for outcome included patient- and procedure-related variables and center volume and surgeon volume. Outcome variables occurring during the Norwood procedure and before hospital discharge or stage II procedure included mortality, end-organ complications, length of ventilation, and hospital length of stay. Univariate and multivariable Cox regression analyses were performed with bootstrapping to estimate reliability for mortality.

Results: Analysis included 549 subjects prospectively enrolled from 15 centers; 30-day and hospital mortality were 11.5% (63/549) and 16.0% (88/549), respectively. Independent risk factors for both 30-day and hospital mortality included lower birth weight, genetic abnormality, extracorporeal membrane oxygenation (ECMO) and open sternum on the day of the Norwood procedure. In addition, longer duration of deep hypothermic circulatory arrest was a risk factor for 30-day mortality. Shunt type at the end of the Norwood procedure was not a significant risk factor for 30-day or hospital mortality. Independent risk factors for postoperative renal failure (n = 46), sepsis (n = 93), increased length of ventilation, and hospital length of stay among survivors included genetic abnormality, lower center/surgeon volume, open sternum, and post-Norwood operations.

Conclusions: Innate patient factors, ECMO, open sternum, and lower center/surgeon volume are important risk factors for postoperative mortality and/or morbidity during the Norwood hospitalization.

Trial registration: ClinicalTrials.gov NCT00115934.

FIGURE 1

Kaplan-Meier estimates and pointwise 95% confidence bands for hospital survival after the Norwood procedure (N = 549). Patients were censored when they were transplanted (n = 9) or discharged (n = 430).

FIGURE 2

Kaplan-Meier estimates for transplant-free survival after the Norwood procedure using all available follow-up (mean, 2.7 ± 0.9 years for survivors). Group classification is according to extracorporeal membrane oxygenation (ECMO), cardiopulmonary resuscitation (CPR), ECMO required to restore circulation during CPR (E-CPR), and none of these interventions (none) within the first 30 days after the Norwood procedure.