Improving the outcome of high-risk neonates with hypoplastic left heart syndrome: hybrid procedure or conventional surgical palliation?

Objectives: Despite significant progress, surgical outcome for high-risk patients with hypoplastic left heart syndrome (HLHS) remain suboptimal. The hybrid palliation lessens the initial operative insult and is expected to improve overall survival; however the outcome of this management sequence is unknown.

Methods: Retrospective review of all high-risk neonates (prematurity, low birth weight, associated genetic or co-morbid conditions) undergoing initial palliation for HLHS either by hybrid or Stage I Norwood procedure at a single institution between January 2001 and December 2006. The two strategies were compared using survival after stage II as the end-point for outcome.

Results: The cohort included 33 patients (14 hybrid and 19 Norwood) with a mean age of 3.8+/-2.4 days, weight of 2.6+/-0.6 kg and Aristotle comprehensive score of 18.7+/-2.5. Aortic atresia was present in 5/14 hybrid and 12/19 Norwood patients. The mean gestational age was 36.8+/-2.2 weeks, six patients were under 36 weeks in each group. Patients undergoing hybrid palliation had a lower preoperative pH [7.14+/-0.2 vs 7.25+/-0.05, p=0.04], higher incidence of organ dysfunction [9/14 (64%) vs 5/19 (26%), p=0.03] and less associated cardiac anomalies [3/13 (21%) vs 13/19 (68%), p=0.009]. Hospital mortality and interstage mortality was 7/33 (21%) and 6/26 (23%) for the entire cohort, without significant differences between the hybrid and the conventional Norwood strategies. Of the original 33 patients only 16 (48.5%) were alive following the second stage procedure (7/14 (50%) hybrid and 9/19 (47.4%) Norwood).

Conclusions: Regardless of the type of initial palliation, high-risk neonates with HLHS continue to have decreased survival. Although the hybrid approach reduces the initial surgical insult, important interstage mortality and ongoing morbidity result in survival no different than with conventional surgical palliation.