Risk Factors for Hospital Morbidity and Mortality After the Norwood Procedure: A Report From the Pediatric Heart Network Single Ventricle Reconstruction Trial

Study Questions:

What are risk factors for morbidity and mortality during the Norwood hospitalization in newborn infants with single right ventricle anomalies enrolled in the Single Ventricle Reconstruction (SVR) trial?

Methods:

This study was a prespecified secondary analysis of data from the SVR trial. Potential predictors included both patient- and procedure-related variables, as well as center and surgeon volume. Outcome variables included mortality, end-organ complications, length of ventilation, and hospital length of stay. Univariate and multivariable Cox regression analyses were performed.

Results:

The analysis included 549 subjects enrolled from 15 centers. Thirty-day mortality was 11.5%, whereas hospital mortality was 16%. Independent risk factors for both 30-day and hospital mortality included lower birth weight, presence of genetic abnormality, extracorporeal membrane oxygenation (ECMO), and open sternum on the day of the Norwood procedure. Longer duration of deep hypothermic circulatory arrest was a risk-factor for 30-day, but not hospital mortality. Shunt type was not a risk factor for either mortality endpoint. 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:

The authors concluded that innate patient factors of lower birth weight and genetic abnormality, as well as ECMO and open sternum, are important risk factors for mortality during the Norwood hospitalization.

Perspective:

Multiple single- and multicenter database reports have attempted to describe risk factors for poor outcomes after the Norwood procedure. Candidate risk factors include low birthweight, genetic abnormalities, restrictive atrial septum, duration of cardiopulmonary bypass, mitral stenosis/aortic atresia anatomy, small aortic size, and a need for ECMO. This study did not show mitral-atresia/aortic stenosis anatomy or small aortic size to be predictive of mortality. Open chest as a predictor of poor outcome is a complex issue. Of 15 centers, seven centers had a policy of leaving the sternum open, whereas eight sternums only did so electively. It is possible that open sternum is either a function of patient status, or is a surrogate for other center-specific practices.

Clinical Topics: Cardiac Surgery, Congenital Heart Disease and Pediatric Cardiology, Invasive Cardiovascular Angiography and Intervention, Cardiac Surgery and CHD & Pediatrics, Congenital Heart Disease, CHD & Pediatrics and Interventions, CHD & Pediatrics and Quality Improvement

Keywords: Birth Weight, Norwood Procedures, Infant, Newborn, Hospital Mortality, Morbidity, Risk Factors, Cardiopulmonary Bypass


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