Common origin of the innominate and carotid arteries: prevalence, nomenclature, and surgical implications

Aortic arch branching consisting of a common origin of the innominate and carotid arteries (COIC) is a normal variant of aortic arch branching in which the right innominate artery and the left common carotid artery share a common trunk and the left subclavian artery arises separately, leaving only two branches arising from the aortic arch. Adachi classified this branching pattern as type B in 1928, but it has also been referred to as a bovine arch, a common brachiocephalic trunk, and, at our institution, an ovine arch. The prevalence of COIC has been reported to be anywhere from 3% to 29% based on angiographic and autopsy studies that comprise relatively small sample sizes. This wide range suggests that the true prevalence is unclear. In addition, the prevalence in individuals with and without structural heart disease has not been clearly defined. Detailed and accurate preoperative anatomic diagnosis is critical to the surgical management of congenital heart disease. Knowledge of the brachiocephalic artery anatomy is relevant in certain surgical procedures and, thus, is routinely defined and communicated to the surgical team. The objectives of this study are to: determine the prevalence of COIC in a large population of individuals with and without structural heart disease; discuss the appropriate nomenclature of this variant; and describe the potential surgical implications.