Postnatal outcome and associated anomalies of prenatally diagnosed right aortic arch with concomitant right ductal arch: a systematic review and meta-analysis

Right aortic arch presents a reported incidence of 0.1% of the general population; the aim of our study was to evaluate the risk of associated intracardiac (ICA), extracardiac (ECA), or chromosomal abnormalities in fetuses with right aortic arch (RAA) and concomitant right ductal arch (RDA). A systematic review of the literature selected 18 studies including 60 cases of RAA/RDA. A meta-analysis with a random effect model calculated for each outcome the pooled crude proportion of associated abnormal outcomes in cases of RAA/RDA and the pooled proportions and odds ratios in RAA with LDA or RDA. Quality assessment of the included studies was achieved using the NIH quality assessment tool for case series studies. RAA/RDA presents risk of associated conotruncal CHDs of about 30% and risk of 22q11 microdeletion in the region of 1%. Two-thirds of 22q11 microdeletions had concomitant thymic hypoplasia and no other chromosomal defects were described. Risks for ICA, ECA, 22q11 microdeletion, and aberrant left subclavian artery are not substantially different in RAA with right or left arterial duct. RAA increases the risk of associated cardiac defects regardless of laterality of the ductal arch. In isolated RDA/RAA cases, absolute risks of extracardiac associated problems or surgery are rather low, we would therefore recommend reassurance, particularly when the thymus and karyotype are normal.