Fetal aortic coarctation: A combination of third-trimester echocardiographic parameters to improve the prediction of postnatal outcome

Abstract

Objectives: This study aims to determine a combination of third-trimester echocardiographic parameters for improving the prenatal prediction of coarctation of the aorta (CoA) after birth.

Methods: We included all cases of suspected CoA during fetal echocardiography performed in the second and/or third trimester of pregnancy at Gaslini Children's Hospital between January 2010 and December 2020. The last prenatal ultrasound evaluation was reviewed considering most of the echocardiographic criteria were already published for prenatal CoA diagnosis. Associated minor cardiac anomalies, such as a ventricular septal defect, persistent left superior vena cava (PLSCV), and redundant foramen ovale (FO) membrane, as well as postnatal outcomes, were reported. Initial perinatal management was defined based on the risk stratification of CoA during prenatal echocardiography. Neonates were divided into two groups depending on the presence or absence of CoA after birth.

Results: A total of 91 fetuses with CoA suspicion were selected, of which 27 (30%) were confirmed with CoA after birth and underwent surgical repair. All cardiac parameters except redundant FO membrane and PLSCV showed a significant correlation with CoA. Statistical analysis confirmed that cardiovascular disproportion with right predominance carries an increased risk for occurrence of CoA, especially if already evident during the ultrasound evaluation in the second trimester. Aortic valve (AV) z-score and distal transverse aortic arch (TAA) z-score resulted as the best predictors of CoA after birth. The best cutoff point for CoA discrimination with ROC analysis was an AV z-score of -1.25 and a distal TAA z-score of -0.37. A total of 46% of those without CoA were diagnosed with a cardiac defect, which was not diagnosed in utero, pulmonary hypertension, or a genetic syndrome.

Conclusion: The current criteria for diagnosing CoA in utero allow accurate diagnosis of most severe cases but the rate of false positives remains relatively high for milder cases. A combination of anatomic and functional echocardiographic parameters might be used in stratifying the risk of CoA. We proposed the AV and the TAA diameter z-scores as the best predictors of CoA after birth. In addition, neonates without CoA deserve proper monitoring at birth because prenatal evidence of a significant cardiovascular discrepancy between the right and left cardiac structures has an inherent risk for additional morbidity postnatally.

Keywords: cardiovascular disproportion; coarctation of the aorta; fetal echocardiography; prenatal diagnosis; risk stratification.

Figure 1

The diagram reproduces the three vessel and the tracheal view and shows the pulmonary artery (PA) leading into the arterial duct (D), the aortic arch (AO), and the superior vena cava (SVC). The lines show the measurement of, respectively, the isthmus (I), the duct, and the distal transverse aortic arch (TA) diameter.

Figure 2

Flow chart of fetuses with suspected coarctation of aorta according to the prenatal risk stratification at last fetal echocardiography and the postnatal findings. The number between brackets indicates the percentage.

Figure 3

Box and whisker plots of the z-score, respectively, for aortic valve annulus and the distal transverse aortic arch at the third-trimester echocardiography.

Figure 4

Box and whisker plots of the z-score, respectively, for aortic valve annulus and the distal transverse aortic arch at the third-trimester echocardiography.

Figure 5

The receiver operating characteristic curve of the z-score aortic valve annulus and the z-score distal transverse aortic arch z-score at the third-trimester echocardiography.