Postnatal circulation in patients with aortic stenosis undergoing fetal aortic valvuloplasty: systematic review and meta‐analysis

OBJECTIVES: Fetal aortic valvuloplasty (FAV) has become a treatment option for critical fetal aortic stenosis (AS) with the goal of preserving biventricular circulation (BVC); however, to date, it is unclear how many patients undergoing FAV achieve BVC. The aim of this systematic review and meta-analysis was to investigate the type of postnatal circulation achieved following FAV. METHODS: The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed. MEDLINE, EMBASE, Web of Science and the Cochrane Library were searched systematically for studies investigating postnatal circulation in patients with AS following FAV. Eligible for inclusion were original papers in the English language, published from 2000 to 2020, with at least 12 months of follow-up after birth. Review papers, abstracts, expert opinions, books, editorials and case reports were excluded. The titles and abstracts of all retrieved literature were screened, duplicates were excluded and the full texts of potentially eligible articles were obtained and assessed. The primary endpoint was type of postnatal circulation. Additional assessed outcomes included fetal death, live birth, neonatal death (NND), termination of pregnancy (TOP) and technical success of the FAV procedure. The quality of articles was assessed using the Critical Appraisal Skills Programme (CASP) tool. To estimate the overall proportion of each endpoint, meta-analysis of proportions was employed using a random-effects model. RESULTS: The electronic search identified 579 studies, of which seven were considered eligible for inclusion in the systematic review and meta-analysis. A total of 266 fetuses underwent FAV with median follow-up per study from 12 months to 13.2 years. There were no maternal deaths and only one case of FAV-related maternal complication was reported. Hydrops was present in 29 (11%) patients. The pooled prevalence of BVC and univentricular circulation (UVC) among liveborn patients was 45.8% (95% CI, 39.2-52.4%) and 43.6% (95% CI, 33.9-53.8%), respectively. The pooled prevalence of technically successful FAV procedure was 82.1% (95% CI, 74.3-87.9%), of fetal death it was 16.0% (95% CI, 11.2-22.4%), of TOP 5.7% (95% CI, 2.0-15.5%), of live birth 78.8% (95% CI, 66.5-87.4%), of NND 8.7% (95% CI, 4.7-15.5%), of palliative care 4.0% (95% CI, 1.9-8.4%) and of infant death 10.3% (95% CI, 3.6-26.1%). The pooled prevalence of BVC and UVC among liveborn patients who had technically successful FAV was 51.9% (95% CI, 44.7-59.1%) and 39.8% (95% CI, 29.7-50.9%), respectively. CONCLUSIONS: This study showed a BVC rate of 46% among liveborn patients with AS undergoing FAV, which improved to 52% when subjects underwent technically successful FAV. Given the lack of randomized clinical trials, results should be interpreted with caution. Currently, data do not suggest a true benefit of FAV for achieving BVC.