Value of two-dimensional speckle-tracking echocardiography in evaluation of cardiac function in small fetuses

Small fetuses include constitutional small for gestational age (SGA) and fetal growth-restricted (FGR) fetuses. Various adverse intrauterine environments can lead to FGR which has higher risk of abnormal perinatal outcome. The fetal heart is very sensitive to the effects of a negative intrauterine environment. Therefore, we used two-dimensional speckle-tracking echocardiography (2D-STE) to evaluate heart function and find more sensitive indicators of pregnancy outcomes of small fetuses.

This prospective cohort study was performed at West China Second Hospital of Sichuan University between July 2023 and December 2023. We prospectively enrolled small fetuses with an estimated weight or abdominal circumference below the 10th percentile for gestational age and controls matched for gestational age. 2D-STE was performed to obtain information on left ventricular function systolic function and strain parameters, including ejection fraction (EF), myocardial global circumferential strain (myoGCS), myocardial global longitudinal strain (myoGLS), endocardial global circumferential strain (endoGCS), endocardial global longitudinal strain (endoGLS), and global radial strain (GRS). The baseline characteristics and various cardiac parameters were compared between the groups. Then, we analyzed the predictive performance of cardiac parameters, and pulsatility index of umbilical artery and middle cerebral artery (UA-PI, MCA-PI) for adverse pregnancy outcomes.

A total of 61 small fetuses and 34 gestational age-matched control fetuses were studied ultimately. The value of EF, myoGCS, myoGLS,endoGCS, endoGLS, and GRS were 44.85±10.04, -11.89±4.24, -9.26±4.24, -22.68±6.24, -13.53±6.67, and 24.98±12.44, respectively, in the FGR group, the absolute values of which were significantly lower than in the SGA group (53.28±6.70, -14.42±4.31, -12.63±4.11, -27.29±7.25, -17.71±5.58, and 33.37±9.33, respectively) and the control group (55.46±6.94, -14.93±4.77, -16.15±3.84, -27.69±6.46, -20.55±4.42, and 36.87±12.69, respectively) (P<0.05). The absolute myoGLS and endoGLS values were significantly lower in the SGA group than in the control group (P<0.05). Combination of endoGLS and UA-PI could represent a new predictor to predict the adverse pregnancy outcomes, and the receiver operating characteristic (ROC) curve exhibited a considerably higher area under the curve (AUC) than either one alone (AUC of 0.75 vs. 0.69 and 0.61, respectively).

The layer-specific strain technique in 2D-STE is a sensitive tool for evaluation of left ventricular myocardial deformation in the heart of small fetuses, and can be used to identify the changes of cardiac function between FGR and SGA. Moreover, the combination of endoGLS and UA-PI as a new parameter may have better performance in predicting pregnancy outcome of small fetuses.