Comparison of cardiac Z-score with cardiac asymmetry for prenatal screening of congenital heart disease.

Abstract

To determine the best screening tests for discriminating early indicators of cardiac hypoplasia in congenital heart disease (CHD) from normal variations in fetal cardiac growth. We retrospectively examined fetal echocardiograms from 90 infants with confirmed CHD: Group 1 (n = 35) with right-sided obstructive lesions and Group 2 (n = 55) with left-sided obstructive lesions. Our control group comprised 2735 normal fetuses, from which we determined fetal cardiac Z-scores of right ventricle (RV), left ventricle (LV), aorta (Ao) and pulmonary artery (PA) diameters and ratios of right to left ventricle (RV:LV) and pulmonary artery to aorta (PA:Ao) size. We compared our control group to Groups 1 and 2 using ANOVA and area under receiver-operating characteristics curve (AUC) analysis. For Group 1, RV:LV ratio, RV-Z-score and PA:Ao ratio were the best screening tests, with highest AUCs (0.879, 0.868 and 0.832, respectively). For Group 2, the Ao-Z-score, PA:Ao and RV:LV ratios were the best screening tests, with AUCs of 0.770, 0.723 and 0.716, respectively. None of the screening tests was found to be a perfect early discriminator for the cardiac lesions tested. Although ratios of PA:Ao and RV:LV are useful, they should be combined with fetal cardiac Z-scores to maximize screening sensitivity.