Evaluation of fetal cardiac function in fetal growth restriction via fetal HQ analysis based on two-dimensional STI

Abnormalities of the fetal cardiovascular system caused by fetal growth restriction (FGR) may lead to adverse outcomes. The fetal cardiac function assessment is of great significance for treatment selection and prognostic evaluation of fetuses with FGR.

This study aimed to explore the value of fetal HQ analysis based on speckle tracking imaging (STI) to evaluate the global and regional cardiac function of fetuses with early-onset or late-onset FGR.

From June 2020 to November 2022, 30 pregnant women with early-onset FGR (21-38 gestational weeks) and 30 pregnant women with late-onset FGR (21-38 gestational weeks) in the Department of Ultrasound, Shandong Maternal and Child Health Hospital were enrolled. Also, 60 healthy volunteer pregnant women were enrolled as two control groups according to the principle of matching gestational weeks (21-38 gestational weeks). The fetal cardiac functions, including fetal cardiac global spherical index (GSI), left ventricular ejection fraction (LVEF), fractional area change (FAC) of both ventricles, global longitudinal strain (GLS) of both ventricles, 24-segmental fractional shortening (FS), 24-segmental end-diastolic ventricular diameter (EDD), and 24-segmental spherical index (SI), were assessed using fetal HQ. The standard biological values of fetuses and Doppler blood flow parameters of fetuses and mothers were measured. The estimated fetal weight (EFW) measured by the last prenatal ultrasound was calculated, and the weights of newborns were followed up.

Among early FGR, late FGR and total control group, significant differences were found in global cardiac indexes of right ventricle (RV), left ventricle (LV) and GSI. For the segmental cardiac indexes, there are significant differences in three groups except parameter of LVSI. Compared with the control group at the same gestational week, the Doppler indexes including MCAPI and CPR in both the early-onset FGR group and the late-onset FGR group were significantly different. The intra- and inter-observer correlation coefficients of RV FAC, LV FAC, RV GLS, and LV GLS were good. Further, the intra- and inter-observer variability in FAC and GLS was small, as analyzed using the Bland-Altman scatter plot.

Fetal HQ software based on STI showed that FGR affected the global and segmental cardiac function of both ventricles. FGR no matter early-onset or late-onset altered Doppler indexes significantly. The FAC and the GLS had satisfactory repeatability in evaluating fetal cardiac function.