8. • Aortic dissections are classified using either of two systems, as
shown below. The DeBakey system classifies a dissection as type I
when it involves both the ascending and descending thoracic
aorta, as type II when it is confined to the ascending thoracic
aorta, and type III when it involves the descending but not the
ascending thoracic aorta. The Stanford system classifies all
dissections that involve the ascending thoracic aorta (i.e., both
DeBakey types I and II) as type A, and those that do not involve the
ascending aorta as type B.