At the vescical temperature of 26°C, hypothermic circulatory arrest is started. The origin of the brachiocephalic artery (BCA) is occluded. The aorta is opened, and the left carotid artery (LCA) is cannulated and perfused. The arch is resected until the origin of the LSA (zone 2), leaving a cuff of aortic tissue incorporating the origins of BCA and LCA. The distal segment of the aorta is reinforced with Teflon felt strips. During this phase, the false lumen is obliterated.