Key clinical point: The Z-sign may serve as a strong marker for a double aortic arch (DAA) in surgically confirmed cases of vascular rings, even in those with atresia of the left arch, and thus facilitate the differentiation between a right aortic arch with left duct (RAA-LD) and DAA in the second trimester of pregnancy.
Main finding: The Z-sign could predict a DAA with a sensitivity of 100% (95% CI 80%-100%), specificity of 81% (95% CI 60%-92%), positive predictive value of 79% (95% CI 57%-91%), and negative predictive value of 100% (95% CI 82%-100%).
Study details: Findings are from a review of the echocardiographic features of 40 fetuses with either DAA or RAA-LD (those with the left duct connecting the pulmonary artery and descending aorta) confirmed during surgery, which displayed the commonest overlap in fetal appearances.
Disclosures: MPM Van Poppel received financial support from the Wellcome/EPSRC Centre for Medical Engineering. The other authors did not report any conflict of interests.
Source: Van Poppel MPM et al. Prenat Diagn. 2022 (Jan 20). Doi: 10.1002/pd.6104.