Aortic Dissection

An aortic dissection occurs when a tear in the inner wall of the aorta causes blood to flow between the inner and outer walls of the aorta, creating a second, false lumen that expands distally and compresses the true lumen. It is a medical emergency. It can be classified into two groups, Stanford Type A (involving ascending aorta and/or arch and/or descending aorta) and Stanford Type B (involving only the descending aorta distal to left subclavian artery). Type A generally requires surgery.

Case #1a. Stanford Type A dissection. Note the false lumen seen in both the ascending and descending aorta.

Case #1b. In this patient, the false lumen extends into the abdominal aorta all the way to the aortic bifurcation. The false lumen is posterior and larger than the true lumen, which is compressed. Note that the inferior mesenteric artery takes off from the true lumen anteriorly.

Case #1c. Same patient as above, lower cut in abdomen. Note that the left renal artery takes off from the false lumen.

Case #2. Stanford Type B dissection.