The reference ranges for fetal ductus venosus flow velocities and calculated waveform indices and their predictive values for right heart diseases.

OBJECTIVES

This study endeavors to establish comprehensive normal reference ranges and Z score formulas for ductus venosus (DV) flow velocity parameters and calculated waveform indices across different gestational ages in low-risk fetuses. Furthermore, we aim to validate the predictive capabilities of these Z score calculation formulas in fetuses with diverse right heart diseases.

METHODS

A total of 8,953 singleton low-risk fetuses and 70 fetuses diagnosed with different types of right heart diseases were retrospectively enrolled. The DV blood flow velocities during the cardiac cycle (ventricular systolic wave velocity [S], ventricular diastolic wave velocity [D], atrial contraction wave velocity [A], and time-averaged maximum velocity [Tamx]) and calculated waveform indices (preload index [PLI], peak velocity index [PVI], pulsatility index [PI], S/A, and S/D) were obtained. Ninety low-risk fetuses were randomly selected as the control group to verify the predictive value of the Z score model for fetuses with different types of right heart diseases.

RESULTS

As gestational age increased (16-39 weeks), the mean values of S, D, A, and Tamx progressively increased; conversely, the mean values of PLI, PVI, PI, and S/A decreased, respectively, and the median value of S/D remained stable. The Z score-transformed A, PLI, PVI, PI, and S/A could serve as predictors of overall right heart diseases. Different DV Doppler parameter Z scores exhibited varying predictive values for different subtypes of right heart diseases.

CONCLUSIONS

Normal reference ranges and corresponding Z score calculation formulas for DV hemodynamic parameters were established, which have demonstrated significant diagnostic values in identifying right heart diseases.