ABSTRACT
Objective To explore the difference in Z-score reference range for aorta measurements, and pulmonary artery(PA)/aortic(AO)valve annular diameter ratio(PA/AO ratio)between normal and aortic stenosis(AS)fetuses and to evaluate the diagnostic value of Z-score of aorta in fetuses with AS. Methods A retrospective cross-sectional study of fetal color Doppler echocardiograms were undertook from 300 singleton normal fetuses with gestational age ranged from 16 to 40 weeks.Standardized fetal echocardiographic measurements included AO valve annular diameter and PA valve annular diameter at end-systole,and PA/AO ratio were obtained.With statistical analysis,best model was established for predicting AO and PA using biparietal diameter (BPD)and femoral length (FL)as independent variables.The correlations between standard deviation (SD)and two independent variables (BPD,FL)were analyzed,and the AO Z-score and PA Z-score of normal fetuses were calculated.One hundred and six singleton fetuses with AS were studied whose gestational age ranged from 1 5 to 40 weeks.The AO Z-score and PA Z-score of AS fetuses obtained by using above regression equation and PA/AO ratio were subsequently calculated.The AO and PA Z-scores and PA/AO ratio between normal fetuses and AS fetuses were compared.And the detection rate of AS according to AO Z-score,PA/AO ratio and AO percentile range were assessed.Results Compared with normal fetuses,the Z-score of AO and the PA/AO ratio in AS fetuses were statistically different (P 0.05).AO Z-score in 96.2% of AS fetuses were found < -3,PA/AO ratio in 95.3% of AS fetuses were found outside 95% CI.The method using AO Z-score had the highest detection rate of AS,the positive predictive value was up to 89.5%,the negative predictive value was up to 98.6%,the sensitivity,specificity and Youden index were 96.2%,96%,and 0.9223,respectively.PA/AO ratio had good but slightly lower diagnostic accuracy than AO Z-score,while AO percentile range performed poor.Conclusions Fetuses whose AO Z-score are outside ±3 and the PA/AO ratio is greater than 1 .4 at the same time are more likely to suffured from AS.Quantification of AO Z-score has important clinical value in the diagnosis of AS,and is more accurate than the percentile range in quantitative assessment of congenital heart growth and development of the fetal pathology of AS.