Coronary arteries are examined closely, and the ostia and proximal arterial course are identified, as are any infundibular branches, if they exist. The coronary ostia and a large "button" of surrounding aortic wall are then from the aorta, well into the sinus of Valsalva; and the proximal sections of the coronary arteries are separated from the surface of the heart, which prevents tension or distortion after anastomosis to the neo-aorta. Infundibular branches are sometimes unable to be spared, but this is a very rare occurrence. If the aortic commissure has not previously been marked, the excised coronary arteries will be used to determine the implantation position of the aorta.