52. Dissecting aortal aneurysm

Organ: Heart, ascending aorta

Description: The left ventricle and ascending aorta are open. There is a rupture in the wall of the ascending aorta. Each side of the ascending aorta has some haemorrhage in the wall of the vessel.

Diagnosis: Stanford A type aortic dissection

Causes:

• Hypertension
• Atherosclerosis
• Marfan syndrome or Ehlers-Danlos syndrome

Theory:

The aorta is split, so the pseudolumen is also split in two, which is why you see it on both the left and the right side of the aorta.

In aortic dissection a rupture of the tunica intima will cause blood to enter the tunica media, ripping it apart (dissecting the aorta). The result is that a new pathway for the blood opens, where the blood can flow through the rupture, between the layers of the wall of the aorta, forming a pseudolumen. Blood flows in the pseudolumen, however blood flow is obviously not as good there as in the real lumen. After the pseudolumen has formed can the arteries that originate from the aorta either originate from the real lumen or the pseudolumen. Arteries that now originate from the pseudolumen get much poorer perfusion, and can cause ischaemia.

Two types of aortic dissection exist, Stanford type A and Stanford type B. In Stanford type A has the aorta dissected from the beginning of the aorta, while in type B has dissection only affected the descending aorta. Type A is obviously worse. The clinical consequence of aortic dissection depends on the type. In type A can the coronaries originate from the pseudolumen, meaning that the coronary perfusion is poor, which can cause myocardial infarction. Surgery can replace the ascending aorta with an artificial graft and connect the coronaries to this graft. Afterward must one must check the perfusion the organs supplied by the aorta. In this case did an aneurysm cause the rupture of the intima, hence the name of the preparation.