Severe structural damage of the seemingly non-diseased infrarenal aortic aneurysm neck

Objective The success of open and endovascular repair of abdominal aortic aneurysms (AAA) is hampered by postoperative dilatation of the anatomical neck of the AAA, which is used for graft attachment. The purpose of this study was to determine whether the macroscopically non-diseased infrarenal aortic neck of AAA is histologically and biochemically altered at the time of operative repair. Methods We harvested full-thickness aortic wall samples as longitudinal stripes spanning from AAA neck to aneurysmal sac in 22 consecutive patients undergoing open surgical AAA repair. Control tissue was obtained from five organ donors and five deceased subjects undergoing autopsy without evidence of aneurysmal disease. We assessed aortic media thickness, number of intact elastic lamellar units, media destruction, and neovascularization grade and performed immunohistochemistry for matrix metalloproteinase (MMP)-9 and phosphorylated c-Jun N-terminal kinase (p-JNK). MMP-9 and p-JNK protein expressions were quantified using Western Blots. Results The median thickness of the aortic media was 1150 μm in control tissue (range, 1000-1300), 510 μm in aortic necks (250-900), and 200 μm in aortic sacs (50-500, P from nonparametric test for trend