Bovine Aortic Arch: Predictor of Entry Site and Risk Factor for Neurologic Injury in Acute Type A Dissection

Background. The aim of this study was to evaluate if the presence of a bovine aortic arch (BAA)-the most common aortic arch anomaly-influences the location of the primary entry tear, the surgical procedure, and the outcome of patients undergoing operation for type A acute aortic dissection (AAD). Methods. A total of 157 patients underwent emergency operations because of AAD (71% men, mean age 59.5 +/- 13 years). Preoperative computed tomographic scans were screened for the presence of BAA. Patients were separated into 2 groups: presenting with BAA (BAAD, n = 22) or not (BAAL, n = 135). Location of the primary tear, surgical treatment, outcome, and risk factors for postoperative neurologic injury and in-hospital mortality were analyzed. Results. Fourteen percent (22 of 157) of all patients operated on for AAD had a concomitant BAA. Location of the primary entry tear was predominantly in the aortic arch in patients with BAA (BAAD, 59.1% versus BAAL, 13.3%; p < 0.001). Multivariate analysis revealed the presence of a BAA to be an independent risk factor for having the primary tear in the aortic arch (odds ratio [OR], 14.79; 95% confidence interval [CI] 4.54-48.13; p < 0.001) but not for in-hospital mortality. Patients with BAA had a higher rate of postoperative neurologic injury (BAAD, 35% versus BAAL, 7.9%; p = 0.004). Multivariate analysis identified the presence of BAA as an independent risk factor for postoperative neurologic injury (OR, 4.9; 95% CI, 1.635-14.734; p = 0.005). Conclusions. In type A AAD, the presence of a BAA predicts the location of the primary entry site in the aortic arch and is an independent risk factor for a poor neurologic outcome. (C) 2014 by The Society of Thoracic Surgeons