Impact of Patient Characteristics and Anatomy on Results of Norwood Operation for Hypoplastic Left Heart Syndrome

Background: We sought to review current-era experience with multistage palliation of neonates with hypoplastic left heart syndrome (HLHS) and to examine the patients' anatomic, and surgical risk factors influencing outcomes.

Methods: A retrospective review of 219 HLHS patients who underwent the Norwood operation from 2002 to 2012 was performed. Competing risks analyses modeled events after the Norwood operation (death/transplantation, progression to Glenn operation) and after the Glenn operation (death/transplantation progression to Fontan operation), and examined the risk factors affecting outcomes.

Results: Competing risks analysis showed that 1 year after the Norwood operation, 25% of patients had died and 75% had undergone the Glenn operation. Three years after the Glenn operation, 11% of patients had died or received transplantation, 48% had undergone the Fontan procedure, and 41% were alive awaiting the Fontan. The overall 8-year survival after the Norwood operation was 66%. The risk factors for mortality on multivariable models were postoperative requirement for extracorporeal membrane oxygenation (hazard ratio [HR]: 3.1 [1.8-5.4], p < 0.001), genetic/major extracardiac anomalies (HR: 2.7 [1.4-5.2], p = 0.002), unplanned cardiac reoperation (HR: 2.5 [1.3-5.0], p = 0.007), modified Blalock-Taussig shunt use (HR: 2.4 [1.4-3.8], p < 0.001), and prematurity (HR: 1.9 [1.1-3.5], p = 0.030). Of note, anatomic factors such as HLHS subtype, ascending aorta diameter, restrictive atrial septum, and associated cardiac lesions did not affect outcomes (p > 0.10 each).

Conclusions: This current single-institution experience demonstrates that patients' factors (ie, prematurity, low weight, genetic/extracardiac anomalies) continue to adversely affect survival. Conversely, surgical and perioperative management advances, along with the use of the right ventricle to pulmonary artery shunt, might have neutralized the effects of anatomic factors on survival. Technical imperfections requiring reoperations are associated with failure to progress through palliation stages and diminished survival.