Type 1 (68%) | Originates in ascending aorta and propagates at least to the aortic arch and often beyond it distally. It is most often seen in patients less than 65 years of age and is the most lethal form of the disease |
Type II (10% - 15%) | Originates in the ascending aorta and is confined to it |
Type III (25% - 30%) | Originates in the descending aorta and rarely extends proximally, but will extend distally. It most often occurs in elderly patients with atherosclerosis and hypertension |
Type IIIa | Propagates proximally or distally, mostly above the diaphragm |
Type IIIb | Propagates distally to the abdominal aorta |