Z-Score Reference Ranges for Angular M-Mode Displacement at 22-40 Weeks' Gestation

Objectives: To construct Z-score reference ranges for fetal mitral and tricuspid annular plane systolic excursions (MAPSE and TAPSE), using angular M-mode (AM) and conventional M-mode (CM).

Methods: A prospective cross-sectional investigation was conducted on 261 normal singleton fetuses from 22 to 40 weeks' gestation. TAPSE and MAPSE were measured by AM and CM. Reference ranges of TAPSE and MAPSE derived from AM and CM were determined against gestational age (GA) and heart area (HA), using regression analyses of the mean and standard deviation.

Results: TAPSE and MAPSE showed positive correlations with GA and HA. A cubic regression was the best-fitted model for the mean of MAPSE and TAPSE based on HA, while a linear regression model was established for the mean based on GA. Z-scores and 95% reference intervals for predicting MAPSE and TAPSE were established. Strong correlations were found between AM and CM, whereas CM underestimated AM (mean error: MAPSE 0.25 ± 0.18 mm; TAPSE 0.35 ± 0.2 mm).

Conclusion: Normal data and the Z-scores of fetal MAPSE and TAPSE were provided against GA and HA, which can be useful for quantitative assessment of fetal cardiac dysfunction, particularly in cases of intrauterine growth restriction.