Prenatal Diagnosis of Bovine Aortic Arch Anatomic Variant

Abstract

Fetal aortic arch development is an early and complex process that depends on many genetic and environmental factors. The final aortic arch varies greatly; it may take the form of a normal arch, anatomic variant (AAAV) with a common origin to that of the innominate artery and left common carotid artery (formerly known as “bovine aortic arch” (with an incidence of up to 27%)) or one of multiple pathological conditions. The present study aimed to establish the feasibility and impact of prenatal anatomic arch variants’ diagnosis. A retrospective study of 271 fetal second- and third-trimester anomaly scans was performed in our tertiary center. Examinations that evaluated the sagittal aortic arch were included and the branching pattern was assessed. Additionally, a literature data search based on the terms “common origin of innominate artery and left common carotid artery”, “bovine arch”, “bovine aortic” and “aortic arch anomalies” was performed. Results that referred to prenatal AAAV were retained and the papers evaluated. In our study, the AAA incidence was 1.93%, with 4 out of 5 cases being arch type B. All cases had minor associated conditions but a good postnatal outcome. An anatomic aortic variant with a common IA and LCCa prenatal diagnosis was found in a small number of studies; most of the cases described in pediatric and adult series were related to cardiac surgery for stenting, aneurysm or thoracic-associated diseases. The incidence of AAAV varied from 6 to 27% depending on the population studied (highest incidence in African individuals). The variant was highly associated with aortic dissection, pulmonary and cerebral embolism and increased risks of incidents during surgery. Diagnosing AAAV during a routine anatomic scan is feasible and diagnoses can be made when anomaly scans are performed. Awareness of the condition is important for postnatal surgery when other cardiac anomalies are found; this can prevent accidents with simple changes to the patient’s lifestyle, and, in the case of surgery, means we can adopt the correct surgical approach.