There are a number of different classifications of aortic dissection:

Stanford classification

This classification is the most common classification and divides the dissections into Type A and Type B.

A Type A dissection involves the ascending aorta and/or the arch while Type B dissections involve only the descending aorta and occur distal to the origin of the left subclavian artery.

DeBakey’s classification

The other commonly used classification is DeBakey’s classification which divides aortic dissections into 3 types: I, II and III.

Table 1: DeBakey’s classification of dissections

Type I Involve the entire aorta
Type II

Involve the ascending aorta and/or the arch of the aorta

Type III Involve only the descending aorta

Reul and Cooley further subdivided De Bakeys classification into subtypes IIIa and IIIb. In IIIa the dissection involves the aorta just distal to the left subclavian artery but extends proximal or distal to this but is largely above the diaphragm. In IIIb the dissection occurs only distal to the left subclavian artery and may extend below the diaphragm.

Svensson’s classification

A more recent classification has been made by Svensson, because intramural haematoma and aortic ulcers may be the only signs of evolving aortic dissection and are not accounted for in the other classification systems.

Table 2: Svensson’s classification of dissections

Class 1 Classic dissection with flap between true and false aneurysm and clot in false lumen
Class 2 Intramural hematoma
Class 3 Limited intimal tear with eccentric bulge at tear site
Class 4 Penetrating atherosclerotic ulcer with surrounding hematoma, usually subadventitial
Class 5 Iatrogenic or traumatic dissection illustrated by coronary catheter causing dissection