Objective: To determine the clinical significance of the right aortic arch (RAA) in a fetus with and without cardiac and extracardiac anomalies.
Methods: This was a retrospective review of all cases of RAA detected prenatally at our institution between March 2005 and December 2009. This retrospective study included 55 fetuses with RAA who were diagnosed based on the presence of the aortic arch being located to the right of trachea in both the three‐vessel view and the trachea view of the heart. Patient charts and recorded images were reviewed in order to identify associated conditions and outcomes. Telephone interviews were conducted to check each patient’s condition in cases of isolated RAA.
Results: Fifty-five cases of RAA were detected prenatally during this study period. One case was diagnosed as double aortic arch on postnatal echocardiography and was therefore excluded from this study. Fourteen cases were prenatally diagnosed with isolated RAA. The follow-up period in our isolated RAA patients ranged from 0.5 to 48 months (mean 14.5 months).
Thirteen of these infants were doing well at the time we prepared this report, and one case is following up. The most commonly associated congenital cardiac anomalies we saw included tetralogy of Fallot, pulmonary atresia with ventricular septal defect, and atrioventricular septal defect (25.9%, 13.0%, and 13.0%, respectively). In fourty cases we detected the coexistence of RAA and extracardiac anomalies, as noted in this study. RAA was seen in seven cases (13.0%) of right isomerism and in one case (1.9%) of left isomerism. Four cases of thirty-five underwent chromosomal study in our series (12.5%) had a microdeletion 22q11. Of the 40 fetuses with associated anomalies, 16 were terminated due to associated, prenatally proven, severe congenital heart anomalies or chromosomal anomalies, one case experienced intrauterine death, and two cases are still being followed.
Conclusion: Based on this study, we strongly suggest that RAA is a benign vascular malformation which does not adversely affect patients postnatally. However, RAA is frequently associated with heterotaxy syndromes as well as with other cardiac malformations and microdeletion 22q11. Therefore, if RAA is identified on prenatal ultrasonography, meticulous inspection of the fetal anatomy must be performed.