Fetal cardiac intervention in hypoplastic left heart syndrome with intact or restrictive atrial septum, systematic review, and meta‐analysis.

To investigate outcomes of fetuses with hypoplastic left heart syndrome (HLHS) with an intact or restrictive atrial septum (I/RAS) managed expectantly or with fetal atrial septal intervention (FASI PubMed, Scopus, and Web of Science were searched systematically from inception until April 2023. Outcomes were classified by those who had FASI and those who had expectant management (EM). To estimate the overall proportion of each endpoint, a meta‐analysis of proportions was employed using a random‐effects model. Heterogeneity was assessed using the I2 value. Thirty‐two studies reporting on 746 fetuses with HLHS and I/RAS met our inclusion criteria. Eleven studies (123 fetuses) were in the FASI group and 21 studies (623 fetuses) were in the EM group. Among the 123 FASI cases, 107 (87%) were reported to be technically successful. The mean gestational age (GA) at diagnosis was comparable between the groups (26.2 weeks FASI vs. 24.4 weeks EM group). The mean GA at FASI was 30.4 weeks (95% CI 28.5, 32.5). The mean GA at delivery was also comparable (37.7 weeks FASI vs. 38.1 weeks EM group). Neonatal outcomes, including live birth, neonatal death, and survival to hospital discharge pooled proportions, were also comparable between groups (live birth: 92% (95% CI 64, 99) FASI versus 93% (95% CI 79, 98) in EM, neonatal death: 32% (95% CI 11, 65) FASI versus 30% (95% CI 21, 41) EM, survival to hospital discharge: 37% (95% CI 25, 52) FASI versus 52% (95% CI 42, 61) EM). Age at neonatal death was higher in the FASI group (mean: 17 days FASI vs. 7.2 days EM group). There was a lower rate of postnatal atrial restrictive septum in the FASI group 38% (95% CI 17, 63) compared to the EM group 88% (95% CI 57, 98). Our review shows variations across centers in the selection criteria and techniques used for FASI. Although survival including livebirth, neonatal death, and survival to hospital discharge did not differ between groups, the procedure may translate into a less restrictive septum at birth. Future multicenter studies are needed to better identify the subset of cases that might have improved outcomes, use standardized definitions, unified techniques, utilize core outcome set, and assess long‐term benefits. Key points: What's already known about this topic? In the setting of hypoplastic left heart syndrome (HLHS), the patency of the inter‐atrial septum is essential to ensure unobstructed drainage of pulmonary venous blood from the left to the right atrium.Prenatal consequences of HLHS with severe atrial restriction include marked elevation in left atrial and pulmonary venous pressures, reduced lung perfusion, and pulmonary lymphangiectasia.Left atrial decompression by the fetal atrial septal intervention (FASI) may offer a means of avoiding or reversing severe pulmonary damage and, thus, a more favorable postnatal outcome. What does this study add? Our review shows variations across centers in their selection criteria and techniques used for fetal atrial septal intervention (FASI) for prenatal hypoplastic left heart syndrome (HLHS) with intact or restrictive atrial septum (I/RAS).There was slightly higher fetal demise in the FASI group.GA at delivery was comparable between FASI and expectant management.Survival outcomes including livebirth, neonatal death, and survival to hospital discharge pooled proportions were also comparable between the two groups.Age at neonatal death was later in the FASI group (mean: 17 days in the FASI vs. 7.5 days in the EM group).47% of FASI cases had postnatal atrial restrictive septum compared to 89% in the expectant group. [ABSTRACT FROM AUTHOR]