Cerebral Blood Flow Characteristics and Biometry in Fetuses Undergoing Prenatal Intervention for Aortic Stenosis with Evolving Hypoplastic Left Heart Syndrome

Abstract

Children with hypoplastic left heart syndrome (HLHS) are at risk for neurodevelopmental dysfunction; prenatal factors may play a role in this predilection. Cerebral blood flow profiles are abnormal in fetuses with HLHS, raising the possibility that cerebral hemodynamics in utero may be related to neurodevelopmental abnormalities. Prenatal aortic valvuloplasty for fetal aortic stenosis with evolving HLHS is technically feasible and improves left heart hemodynamics. This study aimed to assess the effects of prenatal intervention on cerebral blood flow profiles and head circumference in fetuses with evolving HLHS. Seventy fetuses underwent prenatal aortic valvuloplasty for evolving HLHS (median 23 weeks gestation). Among 46 fetuses that had successful valvuloplasty and available data, middle cerebral artery (MCA) pulsatility (PI) and resistive (RI) indices were abnormal (Z-scores −1.7 ± 1.1 and −2.2 ± 1.4, p < 0.001). Early post-valvuloplasty (n = 33) and at late gestation follow-up (n = 28), MCA PI and RI Z-scores remained low with no difference from pre- or early postintervention. Fetal head circumference was normal, as were umbilical artery PI and RI Z-scores. Cerebral blood flow characteristics are abnormal in mid-gestation fetuses with evolving HLHS, suggesting low cerebral vascular impedance. The mechanisms and significance of these abnormalities are unknown. Prenatal aortic valvuloplasty did not have a major impact on these indices.

Cerebral blood flow autoregulation and congenital heart disease: possible causes of abnormal prenatal neurologic development

“…Recently McElhinney et al, evaluating the effects of prenatal aortic valvuloplasty on cerebral blood flow profiles and HC in fetuses with HLHS, concluded that this prenatal intervention did not have a major impact on these indices [20].…”

Reversible Ductus Arteriosus Constriction due to Maternal Indomethacin after Fetal Intervention for Hypoplastic Left Heart Syndrome with Intact/Restrictive Atrial Septum

“…Baseline abnormalities of MCA flow have been documented in fetuses with HLHS [30,31] . Although systemic flow cannot be measured in the presence of ductal constriction, it is likely reduced, which in turn can result in acidosis and potentially fetal demise.…”

Microcephaly is associated with early adverse neurologic outcomes in hypoplastic left heart syndrome

“…Abnormal MCA blood flow has been observed in fetuses with evolving HLHS (21,29,30), but the clinical significance of this finding is unclear. Currently, some centers advocate fetal intervention in fetuses with severe valvar aortic stenosis in order to improve antegrade blood flow across the aortic valve, postulating that this forward flow may prevent the progression of aortic stenosis to HLHS and result in better neurodevelopmental outcomes (31).…”