Evaluation of fetal cardiac functions in the setting of maternal diabetes: Application of the global spherical index, global strain and fractional area change by the speckle tracking technique

Objective: To evaluate ventricular contractility and profile heart deformations in fetuses of hyperglycemic mothers using the Speckle tracking imaging (STI). The fractional area change (FAC), global longitudinal strain (GLS) and global sphericity index (GSI) of the 4-chamber view (4-CV) were computed.

Study design: Dynamic 4-CV images of 60 fetuses exposed to maternal diabetes (MD) and 60 controls were retrospectively collected between 19 and 37 weeks of gestation. Speckle-tracking analysis was used to compute and compare GSI, GLS and FAC of the right ventricle (RV) and the left ventricle (LV) between the groups. By definition, GSI was the ratio of the epicardial basal-apical length in end-diastole (BAL) to the overall transverse length of RV and LV in end-diastole (TL). The FAC was calculated by dividing the difference between end-diastolic area and end-systolic area by the end-diastolic area. Similarly, the GLS of the RV and LV was obtained by dividing the difference between the endocardial length in end-systole and endocardial length in end-diastole to the endocardial length in end-diastole. Data for conventional echocardiographic parameters, standard biological measurements of fetus and maternal baseline characteristics were also recorded and compared between the groups. Linear regression analysis was performed to assess the association between age, BMI and the inter-ventricular septum thickness (IVST).

Results: Gestational age at the time of examination did not differ significantly between the control and gestational diabetes group (p = 0.74). In fetuses exposed to MD, the thickness of the IVS was higher while the FAC of RV, GLS of RV and the GSI were all significantly lower. The FAC and global strain of LV generally decreased with progress in gestation but the difference between the two groups was not statistically significant. Conventional echocardiography in fetuses exposed to MD revealed a lower mitral E/A ratio and a larger myocardial performance index (MPI) of the RV and LV. Although the annular plane systolic excursion (MAPSE), tricuspid annular plane systolic excursion (TAPSE) and septal annular plane systolic excursion (SAPSE) were also lower in this group, the difference was not statistically significant compared to fetuses of the control group. No regression relationship between age, BMI and IVST were noticed in any group.

Conclusion: This study found that diastolic dysfunction among fetuses of gestational diabetic mothers is accompanied by global cardiac deformation and functional decrease of the RV in systole in the second and third trimester. The GSI, global strain and FAC acquired by SRI can be used as convenient and reliable quantitative parameters in the assessment of cardiac function in fetuses exposed to gestational diabetes.