Type A

Dissection involves the ascending aorta and/or aortic arch, and possibly the descending aorta. The tear can originate in the ascending aorta, the aortic arch, or more rarely, in the descending aorta. It includes DeBakey types I and II

Type B

Involves the descending aorta or the arch (distal to the left subclavian artery), without the involvement of the ascending aorta. It includes DeBakey type III