Assessment of fetal cardiac morphology and function in fetal growth restriction: insights from fetal heart quantification technology

Abstract

Background: Research indicates that fetuses with fetal growth restriction (FGR) exhibit cardiac changes before abnormal Doppler blood flow is detected, but the predictive value of these cardiac parameters for diagnosing FGR remains uncertain. Fetal heart quantification (Fetal HQ), a novel technology for assessing fetal heart shape, size, and contractility, was evaluated in this study in terms of its effectiveness in detecting heart changes associated with FGR.

Methods: From January 2023 to July 2023, 38 fetuses with FGR and 44 gestational-age-matched controls were selected at The Second Affiliated Hospital of Wenzhou Medical University. All participants underwent routine obstetric ultrasound, fetal echocardiography, and Fetal HQ. Cardiovascular parameters, the sphericity index (SI), and fractional shortening (FS) of 24 segments in both ventricles, along with their standard scores (Z-scores), were documented. The participants were followed up until birth, and then clinical data and cardiovascular measurements were collected and analyzed.

Results: There were no significant differences in age, height, or body mass index (BMI) between the fetuses with FGR and the controls [age: 30.32±4.18 vs. 30.84±4.31 years, P=0.578; height: 158.39±4.68 vs. 160.34±5.25 cm, P=0.080; BMI: 26.67 (24.02, 27.60) vs. 26.43 (23.98, 28.60) kg/m², P=0.937], Statistically significant differences were observed in left ventricular global longitudinal strain (LVGLS), right ventricular global longitudinal strain (RVGLS), four-chamber view (4CV) transverse width end diastole (4CVTWED), and the 4CV global spherical index (4CVGSI) between the groups (all P values <0.05). There were no significant differences between the two groups in terms of 4CV end-diastolic long diameter (4CVLED), 4CV area, left ventricular end-diastolic long diameter (LVLED), left ventricular end-systolic (LVES) area, left ventricular end-systolic long diameter (LVLES), right ventricular end-diastolic (RVED) area, right ventricular end-diastolic long diameter (RVLED), right ventricular end-systolic (RVES) area, and right ventricular end-systolic long diameter (RVLES), or the ratios of left ventricular end-diastolic (LVED) area to RVED area and LVLED to RVLED (all P>0.05). FS was significantly lower in the multiple left ventricular FS (LVFS)1-17 and right ventricular FS (RVFS)1-8 segments in the FGR group (all P<0.05). No significant differences were found in left ventricular SI (LVSI)1-24, right ventricular SI (RVSI)1-24, LVFS18-24, and RVFS9-24 between the groups (all P values >0.05). The FGR group, as compared to the control group, had significantly more cases with abnormal Z-scores (>2 or <-2: 84% vs. 52%, P=0.002) and with abnormal Z-scores in two or more parameters (50% vs. 12%, P<0.001). The interobserver intraclass correlation coefficient (ICC) for fetal parameters ranged from 0.72 to 0.80, and the intraobserver ICC ranged from 0.79 to 0.86.

Conclusions: FGR fetuses exhibited notable cardiac abnormalities and impaired ventricular function. Fetal HQ technology can effectively evaluate these cardiac changes, offering crucial insights for clinical antenatal care.

Keywords: Fetal heart quantification (Fetal HQ); fetal growth restriction (FGR); heart morphology; ventricular function.

Figure 1

The movement of the LV (left panel) and of the RV (right panel). The green line delineates the endocardium during diastole, whereas the yellow line delineates the endocardium during systole. The global strain was calculated automatically based on the endocardial movement. ED, end-diastolic; ES, end-systolic; LV, left ventricle; RV, right ventricle.

Figure 2

The 4CVGSI at end diastole measured by fetal HQ. 4CV, four-chamber view; 4CVGSI, four-chamber view global spherical index; 4CVLED, four-chamber view end-diastolic long diameter; 4CVTWED, four-chamber view transverse width end diastole; GSI, global spherical index; HQ, heart quantification; ZS, standard score.

Figure 3

A pregnant women in the FGR group was 31 years old, was 36 weeks into gestation, and had a neonatal weight of 1,910 g. (A) The LVSI, where segments 1–15 exhibit reduced SI values, with Z-scores less than −2 (highlighted in orange). (B) The RVSI. Segments 1–9 have similarly low SI values, with Z-scores below −2 (highlighted in orange). (C) The LVFS. Segments 1–2, 8–12, and 20–24 have decreased FS values and Z-scores less than −2 (highlighted in orange). (D) The RVFS, with each segment in the normal range. FGR, fetal growth restriction; FS, fractional shortening; LVFS, left ventricular fractional shortening; RLVSI, left ventricular sphericity index; RVFS, right ventricular fractional shortening; RVSI, right ventricular sphericity index; SI, sphericity index; Z-score, standard score.