OP02.04: Applications of z‐scores of mitral‐tricuspid valve distance in screening of fetal Ebstein anomaly

Z-scores for mitral -tricuspid valve distance (MTD) in normal fetuses and fetuses with Ebstein anomaly were developed from the measurements of femur length (FL), biparietal diameter (BPD) or gestational age (GA) using fetal echocardiography. A retrospective cross-sectional study of 1216 singleton normal fetuses (20 ∼ 40 weeks) and 15 fetuses (19 ∼ 36weeks) with Ebstein anomaly was performed. MTD was measured in a standard apical four-chamber view. MTD z-scores for normal fetuses and fetuses with Ebstein anomaly were compared. Compared with normal fetuses, the MTD in fetuses with Ebstein anomaly was statistically increased(P < 0.01), the MTD in normal fetuses was (3.5 ± 0.6)mm with a range of 0.9 ∼ 5.5 mm, while the MTD in fetuses with Ebstein anomaly was (9.6 ± 2.5) mm with a range of 4.5 ∼ 11.4 mm. The MTD z-score in fetuses with Ebstein anomaly was statistically different (P < 0.01), the MTD z-score in 100% fetuses with Ebstein anomaly were found > +3. Normal reference ranges z-scores for MTD may be useful for the assessment of fetal cardiac growth and development, especially has important applications in prenatal diagnose of Ebstein anomaly.