Abdominal aortic aneurysm

• abdominal aorta is most common site for aortic aneurysm

CT scan

• aorta shouldn’t be that big

• white is blood, but there is a thrombus around it

Grossly

• most common site: infrarenal aorta—above the iliacs

• when you open the aortas up, they are packed in with thrombus

Pathology

• destruction and thinning of aortic media

• atheromatous changes

• usually, large thrombus

Pathogennesis

• atherosclerosis and hypertension

• genetic factors (“this is sort of disturbing because my uncle had one”)

• imbalance in collagen degradation and synthesis, related to inflammation

Clinical features

• rupture: massive, often fatal hemorrhage

• obstruction of branch vessel—ischemia

• impingement of adjacent structures

Risk of rupture increases with size

• <>

• 5 cm or above: 11% per year, which is when vascular surgeons intervene

• Laplace’s law: at constant pressure, surface tension is directly related to radius, so if the blood pushes the wall out a bit, then the surface tension increases, weakening the wall; then the blood pushes the wall out a little bit more, and surface tension goes up and the wall gets even weaker, and eventually the wall rips open

Treatment

• open surgery

• endovascular stents

• treat before rupture. after rupture, mortality is 50%

Category: Medical Subject Notes , Pathology Notes