Survival After Norwood Procedure in High Risk Patients

Purpose: Historical studies have identified multiple single ventricle populations at increased risk for mortality following the Norwood Procedure. These pre-operative risk factors include low birth weight (LBW), restrictive or intact atrial septum or obstructed pulmonary veins, ventricular dysfunction and atrioventricular (AV) valve regurgitation. Data is lacking on longer term outcomes for these high risk populations and it remains unclear whether contemporary survival in these groups has improved along with overall Norwood survival. We sought to report outcomes of the Norwood procedure in high risk patients and compare these results to standard risk patients in the recent era. Methods: All patients born with Hypoplastic Left Heart Syndrome (HLHS) or variants with aortic hypoplasia between 2006 and 2016, who underwent a Norwood procedure at our institution were included. Retrospective review of patient data, including demographics and operative characteristics, was performed and Kaplan-Meier analysis was used to evaluate survival between groups. There were 4 high risk groups created based on pre-operative findings of: 1) LBW, defined as birth weight of < 2500 grams, 2) an intact or restrictive atrial septum, defined as having a mean echo gradient of >8mmHg, or obstructed anomalous pulmonary venous return (septum/veins group), 3) > moderate AV valve regurgitation or > moderate ventricular dysfunction (dys/insuff group) and 4) those with multiple of these high risk co-morbidities (multiple group). Results: The cohort included 177 patients. There were 50 patients categorized as high risk preoperatively due to LBW (n=18), ventricular dysfunction or AV valve regurgitation (n=13), intact or restrictive atrial septum or obstructed anomalous pulmonary venous return (n=14), or multiple factors (n=5). There were 2 (1.6%) deaths prior to Glenn in the standard risk group with a total of 10 (20%) from the high risk groups (p