EP09.72: Aortic isthmus flow characteristics throughout gestation in fetal coarctation of the aorta

To evaluate aortic isthmus flow characteristics by colour and pulsed Doppler in a series of fetuses with confirmed coarctation of the aorta (CoA). Retrospective study including 33 fetuses with confirmed CoA evaluated in a tertiary hospital (BCNatal: Hospital Clínic and Sant Joan de Déu) between 2016 and 2023. Suspicion of CoA was based on the presence of indirect signs at echocardiography (right dominance > 1.3) with a size of the aortic isthmus < -2 z score. Flow at aortic isthmus level was evaluated in the three-vessel-trachea and in the sagittal aortic arch views by colour Doppler and pulsed Doppler. Presence of reverse flow (in systole and/or diastole) as well as persistence of diastolic flow (compared to the ductus arteriosus flow and confirmed by pulsed Doppler) were assessed in all cases from diagnosis to the third trimester of pregnancy. Mean gestational age at suspicion of CoA was 23.4 ± 4.4 (mean ± SD) weeks. A total of 113 echocardiograms [range 1-7 per patient] were performed during the study period. At suspicion of CoA, most of the fetuses (73%, 24/33) showed a persistent diastolic flow in the aortic isthmus, which remained present beyond 28 weeks (67% of the cases). On the contrary, reversed flow in the aortic isthmus (in systole) appeared in most cases in the third trimester (9 cases at diagnosis and 22 cases > 28 weeks). Persistent diastolic flow is the most frequent flow pattern in the aortic isthmus in fetuses with confirmed CoA. It remains relatively stable throughout gestation compared with bidirectional reverse flow that appears more frequently in the third trimester. Further studies are needed to confirm these results and assess their potential clinical applicability. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.