Figure 3.

Illustrative demonstration of different types of AAS. Disruption of media layer of the aortic wall is a common feature to AD, IMH, PAU. (A) PAU is an ulcerated plaque that has extended into the vascular media. There is a common pathophysiologic mechanism between IMH (B) and AD (C). AD results from splitting of the layers of aortic wall with an entrance tear. An intimal flap separates the TL, which is continuous with the non-dissected aortic segment, from the FL. The only difference between the two being the presence of a re-entrance tear large enough to maintain the patency of a FL in AD. FL can have variable degree of thrombus depending on the flow dynamics. AAS, acute aortic syndrome; TL, true lumen; AD, aortic dissection; IMH, intramural hematoma; PAU, penetrating aortic ulcer; FL, true lumen.