Z-score analysis of mitral-tricuspid valve distance in normal fetuses with fetal echocardiography / 中华超声影像学杂志

ABSTRACT

Objective To develop Z-score reference ranges for mitral valve-tricuspid valve distance (MTD) in normal fetuses from the measurements of femur length (FL),biparietal diameter (BPD) or gestational age (GA) using fetal echocardiography.Methods A retrospective cross-sectional study of 1216singleton normal fetuses was performed.The gestation age ranged from 20 to 40 weeks.Non-cardiac fetal biometric parameters included FL and BPD and GA based on menstrual age.MTD was measured in a standard apical four-chamber view.Normal Z-score ranges were developed for MTD using GA,BPD and FL as independent variables.These were accomplished by using first standard regression analysis and then weighted regression of absolute residual values for each parameter in order to adjust for inconstant variance.Results Linear regression model was the best description of the data in each case and correlations between MTD and independent variables (FL,BPD,GA) were excellent.The linear regression equations between MTD and FL,BPD,GA were:Y =0.04629 × FL-0.02868 (r =0.827) ; Y =0.04018 × BPD-0.08293(r =0.767) ; Y =0.0098 × GA-0.07075 (r =0.721),respectively.Heteroscedasticity of standard deviation(SD) with increasing independent variables also could be modeled with a simple linear regression.Linear regression equations between SD of MTD and FL,BPD,GA were:Y =0.0149 × FL-0.0095 (r =0.9947),Y =0.0126 × BPD-0.02793 (r =0.9931),Y =0.00305 × GA-0.021 (r =0.991),respectively.According to these equations,MTD Z-score =(the actual measurement of MTD-predicted MTD)/prediction SD.Conclusions Normal reference ranges and Z-scores for MTD have been provided.These normative data may be useful tools for assessment of fetal MTD,especially has potential applications in Ebstein anomaly or other malformations involved atrioventricular valves.