Hypoplastic left heart syndrome: Hybrid approach?

Dear Editor,

Chen et al. report on the single-centre experience with the increased use of the Hybrid procedure in newborns with hypoplastic left heart syndrome but without improvement in early survival [1]. Despite the notable contributions of the institution (CHOP) in pioneering the Norwood procedure, the rationale behind the institutional introduction and growing preference for the stage-1 Hybrid procedure (hS1P) up to 30% in recent years despite a significant decline in the total number of Norwood operations remains enigmatic. A greater clarity regarding the adoption of the Hybrid approach is obvious. The question rises if the shift towards hS1P was due to the plateaued operative mortality or based on morbidity criteria following Norwood surgeries [2]. Without the knowledge of technical details of the utilized hS1P with included periprocedural intensive care necessitates, the analysed discrepancy in both procedural outcomes cannot be retraced. Additionally, it stays open how in future the newborns with (multiple) risk factors will be treated at CHOP.

Given the high operative mortality of hS1P, which contrasts with other institutions, it is either used as a two-stage (surgical/transcatheter) approach akin to the Giessen Hybrid [3] or as a single surgical stage according to the Columbus approach [4]. First and foremost, components of Hybrid approach consisting of bilateral Pulmonary artery (PA) banding, ductal stenting and atrial septum manipulations, if necessary, are the most effective rescue measures for hypoplastic left heart syndrome neonates in shock [3]. Definitively, a blanket discrediting of the Hybrid procedure only based on negative institutional experiences and added with supposedly appropriate references do not support progress and innovations, and do not contribute to improve one’s own results.

Prospective randomized comparative studies would justify the impact of neonatal ‘Norwood versus Hybrid’ surgeries, provided the entry criteria ensure method comparability’s and perioperative strategies. Studies labelled as ‘evidence-based’ but with unsuitable inclusion criteria do not. In contrast, potentially ‘guideline-relevant’ results can be disastrous as happened with the use of beta-blockers in paediatric heart failure. Probably, this is the reason why ß1-specific adrenoreceptor blockers are currently only used in a few institutions for treating infants in the interstage after S1P. Preventing similar scenarios with the hS1P or prospectively with complete percutaneous S1P, biased generalizations should be avoided.

Hybrid-S1P, only based on treating high-risk patients, limits knowledge acquisition encompassing technical aspects and objectives with consecutive inevitable outcome differences. What applies to the Norwood operation also applies to hS1P.

In conclusion, a better understanding of the technical nuances of the Hybrid procedure and its comparative effectiveness is crucial for informed decision-making in paediatric cardiac surgery. A Hybrid technique focusing on surgical bilateral banding with refined postoperative care could present an opportunity to improve acute surgical outcomes and potentially enhance quality of life if follow-up treatment is ensured [2]. It is prudent to anticipate that surgical S1P may soon be replaced by nearly non-invasive percutaneous transcatheter techniques [5]. Thus, readiness for such advancements is paramount.

FUNDING

The author has no funding.

Conflict of interest: none declared.

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