Evaluation of the trachea in fetuses with vascular ring using prenatal ultrasound

Vascular ring (VR) can present when vessels encircle and compress trachea, which may lead to early clinical symptoms. Accurate prenatal assessment of fetal trachea could provide relevant information for perinatal management. This study aimed to quantitatively evaluate tracheal compression caused by VR in fetuses using prenatal ultrasound. The data of fetuses with VR diagnosed by ultrasound were retrospectively analysed, which were divided as those with complete VR including double aortic arch (DAA), right aortic arch with an aberrant left subclavian artery and a left patent ductus arteriosus (RAA-ALS), and those with incomplete VR as aberrant right subclavian artery (ARS). Pregnancies with normal fetuses were recruited as control. Tracheal internal diameters (TID) and z scores against gestational age was assessed. The Fetuses were divided into two groups based on tracheal compression for the comparison of z scores. The ROC curve for z score cut-offs and prediction of significant trachea compression was plotted. A total of 80 fetuses with VR were diagnosed. 67 normal fetuses were enrolled. The difference in normal group and incomplete VR group (43) was not significant (2.4 ± 0.5 vs. 2.4 ± 0.4, P > 0.05), while TID and z scores were significantly lower in fetuses with complete VR (37)(1.4 ± 0.5 vs. 2.4 ± 0.5, P < 0.05; -1.2 (-1.5, -0.8) vs. 0.3 (-0.1, 0.6), P < 0.05). The AUC was 0.946 (95% CI, 0.90-1.00). Using a TID z scores cut-off of -0.44, the sensitivity was 89%, and the specificity was 92%. Prenatal tracheal compression may happen in infants with VR and cause clinical symptoms. We found that complete VR could lead to even more severe compression of fetal trachea. Prenatal surveillance of TID and comparison to z score reference ranges could be necessary in this subset of fetuses. 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.