95 - Right ventricular dominance predicts postnatal intervention requirement in those with fetal suspicion of coarctation of the aorta

A total of 75 newborns were included, of which 59 (79%) had an aortic arch with non-significant obstruction upon ductal closure, and 16 (21%) underwent a neonatal intervention for a confirmed CoA. Compared to the controls, those with CoA had increased right to left ventricular dominance. Indeed, they had an increased right to left ventricular end-diastolic area [RV/LV EDA] ratio in the apical view (1.21 [0.32] vs 1.63 [0.34]; p< 0.0001) and an increased tricuspid to mitral valve diameter ratio (1.23 [0.23] vs 1.51 [0.32]; p=0.0001). The increased EDA ratio in those with CoA is due to these fetuses having a smaller left ventricle as opposed to a larger right ventricle. As such, the LV-EDA Z score was increased in the control group (-1.64 [-2.51 – -0.76] vs -2.62 [-3.14 – -1.94], p=0.02). A decreased right ventricular peak longitudinal strain was observed in the CoA group (-20.95 [2.96] vs -18.56 [3.14] %, p=0.006). No correlation was found between fetal isthmus diameter and the development of CoA. The RV/LV EDA ratio was the most sensitive predictor of CoA and identified all cases with CoA. Indeed, a cut-off >1.229 had a specificity of 66.1% and a sensitivity of 100% (receiver operating characteristic curve with an area under the curve of 0.84).

Conclusion(s): Right ventricular dominance, especially the right to left ventricular end-diastolic area ratio in the fetal apical 4-chamber view, is a useful tool to identify low-risk for a true CoA during fetal life.