10
Introduction
Figure 7. Classification of Acute Aortic Dissection
e DeBakey system categorizes dissections into types I, II, and III, based on the origin
of the intimal tear and the extent of the dissection:
• Type I: Dissection tear originates in the ascending aorta and propagates distally
to include the aortic arch and typically the descending aorta
• Type II: Dissection tear is confined only to the ascending aorta
• Type III: Dissection tear originates in the descending thoracic aorta and
propagates most often distally
▶ Type IIIa: Dissection tear is confined only to the descending thoracic aorta
▶ Type IIIb: Dissection tear originates in the descending thoracic aorta and
extends below the diaphragm
e Stanford classification system divides dissections into 2 categories according to
whether the ascending aorta is involved or not, regardless of the site of origin:
• Type A: All dissections involving the ascending aorta, irrespective of the site of the
intimal tear
• Type B: All dissections that do not involve the ascending aorta (including dissections
that involve the aortic arch but spare the ascending aorta)
