Fig. 1.  Visualizing the surgical site and region of aortic cross-clamp. (A ) Post mortem dissection of the heart and thoracic vascular tree showing the location of descending aorta cross-clamp (arrow ). Intravascular perfusion with 1% Evans Blue dye was used to visualize the heart and vasculature. (B ) Example of intraoperative exposure of the descending thoracic aorta (white arrow ). Thin black arrow  indicates direction of blood flow. White arrow  indicates location of aneurysm clip. (C ) The same surgical site as in B  but after placement of the aneurysm clip. Note blanching of the aorta distal to the clip, indicating lack of blood flow. Scale bar in C = 1.6 mm and applies to B  as well. BCA = brachiocephalic artery; LCCA = left common carotid artery; LSA = left subclavian artery.