Retrograde Flow in the Aortic Isthmus: Trigger to Deliver Growth Restricted Fetuses Between 30 and 34 Weeks of Gestation?

Abstract

Objective To evaluate the association of aortic isthmus (AoI) circulation assessed by doppler imaging in growth restricted fetuses with perinatal outcome.

Design Prospective longitudinal observational study.

Setting Tertiary referral center.

Population Fetal growth restriction (FGR) (n = 38) between 24 and 36 weeks’ gestation.

Methods Doppler examination of the aortic isthmus, umbilical artery (UA), middle cerebral artery, and ductus venosus (DV) was performed. The relationship between perinatal outcomes and antegrade (n = 25) and retrograde flow (n = 13) in the AoI and other Doppler parameters was analysed.

Results Retrograde AoI group had higher rates of adverse perinatal outcome (92.3% vs. 72%) with 63.1% sensitivity and 87.5% specificity. Overall perinatal mortality (intrauterine death and neonatal death) was higher in the retrograde group (23%). No perinatal mortality was seen in the antegrade AoI group. Cases with absent end diastolic flow (AEDF) or reverse end diastolic flow (REDF) in the UA and retrograde flow in the AoI and normal DV flow had 40% prenatal mortality as 25% in those with abnormal DV Doppler.

Conclusion Retrograde blood flow in the AoI is associated with adverse perinatal outcome, particularly intrauterine fetal demise, neonatal death, Respiratory Distress Syndrome (RDS) and increased duration of Neonatal Intensive Care Unit (NICU) stay. Even if DV flow is normal, adverse outcome might be suspected in fetuses with AEDF/REDF in the UA and retrograde flow in the AoI. Consequently, retrograde flow in the AoI might be considered as an additional trigger for delivering FGR fetuses at 30–34 weeks with AREDF in the UA. Larger longitudinal studies are, however, required to vaidate this.

Keywords

Fetal growth restriction, FGR, IUGR - Doppler ultrasound - Fetal aortic isthmus - Aortic isthmus - Perinatal outcome