Extracorporeal circulation is a method in cardiovascular surgery that can be used in different variations. Computational fluid dynamics can be applied to predict the impact of a certain technique for a patient preoperatively, by taking the patient-specific physiology into account. By the developed methodology, the aortic geometry of a patient can be captured and analyzed. In the present work, the physiological blood flow, as well as the antegrade extracorporeal circulation are computationally investigated for a patient with an anomaly in the aortic physiology. The same flow configurations are investigated for an idealized aorta. The results are compared. It is shown that the consequences of the antegrade extracorporeal circulation for an abnormal and idealized/normal aorta turn out to be different. This comparison indicates that it is commendable to perform a patientspecific detailed computational analysis in advance, for the patients with abnormal physiology, instead of assuming a normal behavior for extracorporeal circulation.