Hybrid procedures in the management of hypoplastic left heart syndrome: a systematic review

Abstract Background/Objectives: Hypoplastic left heart syndrome is considered one of the most severe CHDs and occurs in approximately 2–3% of all CHD cases. Hybrid procedures have been introduced as an alternative to traditional surgical techniques, such as the Norwood procedure, particularly for neonates at high risk. Although hybrid approaches claim to reduce surgical risks and improve recovery, little is known regarding their comparative effectiveness and safety. This review aims to describe the contribution of hybrid procedures in hypoplastic left heart syndrome management regarding survival rates, postoperative complications, and quality of life, through recovery outcomes and long-term results, in light of conventional surgical techniques. Methods: A systematic review was carried out following the PRISMA guidelines. Data were retrieved from PubMed, Scopus, Web of Science, and Cochrane Library. The search articles were published from January 2014 to November 2024. Inclusion was focused on paediatric patients diagnosed with hypoplastic left heart syndrome and studies comparing hybrid procedures versus traditional surgical methods. All screening, data extraction, and quality assessment were done by two independent reviewers. Results: This review analysed data from 11 studies comprising 934 neonates with hypoplastic left heart syndrome, of whom 371 underwent hybrid procedures (HP) and 563 received the Norwood procedure. The findings demonstrated that both approaches achieved comparable survival rates at 1, 3, and 5 years. Hybrid procedures were linked to slightly earlier interventions (standardised mean difference = −0.10, 95% confidence interval: −0.61 to 0.41, p = 0.77) and were favored for high-risk neonates due to reduced invasiveness. However, hybrid procedures showed a higher rate of interstage events (risk ratio = 0.81), 95% confidence interval: −0.62 to 2.25, p = 0.09) and higher rates of pulmonary artery stenosis requiring reinterventions (30% vs. 18% for Norwood). Norwood procedures were associated with fewer reinterventions and lower interstage event rates, highlighting their effectiveness for stable patients. Conclusions: Hybrid procedures offer a practical alternative to the Norwood procedure, especially for high-risk neonates. Although both approaches show similar long-term survival rates, hybrid procedures are associated with a higher risk of complications, including increased interstage mortality. These challenges highlight the need for continued advancements to refine hybrid techniques and to improve long-term outcomes. This review emphasises the critical role of tailored patient selection and calls for further research to enhance hybrid procedure protocols and optimise their effectiveness for specific patient populations.