Fetal Echocardiographic Dimension Indices: Important Predictors of Postnatal Coarctation

The aim of the study is to identify reliable quantitative fetal echocardiographic predictors for postnatal development of coarctation (CoA). In this retrospective study, we included 65 fetuses with a prenatally suspected, isolated CoA, born 2010-2018. Dimensions of the cardiac structures, aortic, and ductal arches expressed as ratios and Z-scores were analyzed in relation to outcome. Fetuses that developed CoA postnatally (34%) exhibited significantly smaller Z-scores of left cardiac structures from the mitral valve to the aortic isthmus. The most sensitive and specific predictors were a carotid-subclavian artery index (CSAI) of < 0.78 (92.3% sensitivity, 96.8% specificity) or a product of isthmus-to-duct ratio in the three-vessel trachea view (3VT) and the mitral-to-tricuspid valve ratio (I/D_3VTxMV/TV) of < 0.37 (100% sensitivity, 94.6% specificity). When comparing different Z-score datasets, we observed large and highly significant differences. Postnatal CoA can be predicted with high accuracy during fetal life using CSAI or I/D_3VTxMV/TV. The latter may be particularly useful if adequate sagittal aortic arch images cannot be obtained. As significant and clinically unacceptable differences in Z-scores were observed for the same measurements, this calls for a large multi-center collaboration to generate reliable fetal echocardiographic Z-scores.