Study on establishing the reference range of atrial septal excursion index and foramen ovale membrane angle in normal fetuses aged 16-40 weeks / 中华超声影像学杂志

ABSTRACT

Objective:To establish the normal reference range of atrial septal excursion index (ASEI) and foramen ovale membrane angle in normal fetuses aged 16-40 weeks, and to analyze the correlation between ASEI and foramen ovale membrane angle in normal fetuses.Methods:A total of 378 normal singletons with gestational ages of 16-40 weeks undergoing by fetal echocardiography were selected in the Department of Diagnostic Ultrasound & Echocardiography, Sir Run Run Shaw Hospital, Zhejiang University College of Medicine, from January to June 2021, and 349 fetuses successfully finished all measurements. After all fetuses completed the systematic fetal echocardiography, fetal foramen ovale diameter and foramen ovale membrane angle were measured on the four chamber view. The maximum distance of foramen ovale valve from the base of atrial septum to the free wall of left atrium and the transverse diameter of left atrium were measured, and ASEI was calculated. The differences of ASEI, foramen ovale membrane angle and foramen ovale diameter of the groups with different gestational weeks were compared. The correlations among ASEI, foramen ovale membrane angle and foramen ovale diameter were analyzed by Pearson correlation analysis.Results:All 349 fetuses were divided into 6 groups according to their gestational weeks, including 17 cases at 16-20 weeks, 46 cases at 21-24 weeks, 114 cases at 25-28 weeks, 105 cases at 29-32 weeks, 31 cases at 33-36 weeks and 36 cases at 37-40 weeks. The ± s of ASEI was 0.492 7±0.059 7, 95% CI was 0.486 4-0.499 0, 95% normal reference value range was 0.375 7-0.609 8. Significant differences were found in ASEI among different groups( P<0.05). The ± s of foramen ovale membrane angle was (44.03±5.48)°, 95% CI was 43.46-44.61°, 95% normal reference value range was 33.29-54.78°. Significant differences were found in the foramen ovale membrane angle among different groups( P<0.05). The ± s of foramen ovale diameter was (4.32±1.30)mm, 95% CI was 4.18-4.45 mm, the differences among different groups were significant( P<0.05) and foramen ovale diameter was found increased with the increase of gestational weeks. There was a significant positive correlation between ASEI and foramen ovale membrane angle ( r=0.558, P<0.05). There was no correlation between foramen ovale diameter and ASEI and foramen ovale membrane angle ( r=-0.166, -0.084; all P>0.05). Conclusions:The normal reference ranges of ASEI and foramen ovale valve angle of normal fetuses aged 16-40 weeks was successfully established. These parameters may be useful for evaluating diastolic cardiac function by assessing foramen ovale.