Abdominal aortic aneurysm and aortic occlusive disease: a comparison of risk factors and inflammatory response

Objective: to compare patients with abdominal aortic aneurysm (AAA) and aor tic occlusive disease (AOD) with regard to risk factors for atherosclerosis , co-morbid conditions and inflammatory activity. Patients and methods: a fetal Of 155 patients undergoing abdominal aortic s urgery between January 1993 and October 1997: 82 (53%) had aneurysmal disea se and 73 (47%) had occlusive disease. Principal risk factors were compared : age; gender; smoking; hypertension; hyperlipidaemia; diabetes mellitus; s evere peripheral vascular disease (PVD) and ischaemic heart disease. Aortic wall tissue samples were obtained during surgery. A prospective blind anal ysis was performed for the presence of inflammatory cytokines TNF-alpha, IL -1 beta IL-6 and TGF-B. Results: the average age of AAA patients was 74 years (50-88), while that o f AOD patients was 61 years (43-82) (p<0.0001). Diabetes mellitus was found to be much more prevalent in the AOD group (p<0.001), while hypertension a nd severe PVD were more prevalent in the AAA group (p<0.001). No difference s were found concerning any of the risk factors. Inflammatory cytokine acti vity: AAA tissue samples contained significantly higher mean TNF-<alpha> an d IL-6 levels compared to the AOD samples (5.6+/-2.7 x 10E-4 vs. 4.4+/-2.7 x 10E-5 atmoles/mul (p=0.01), and 0.6 +/- 0.4 vs. 0.01 +/- 0.006 atmoles/mu l (p = 0.02) respectively). No differences were found related to IL-1 beta and TGF-beta. Conclusions: (1) Patients with AAA have fewer atherosclerotic risk factors than no patients with AOD. (2) Patients with AAA and AOD have significantly different inflammatory activity. (3) The data supports the hypothesis that AAA and AOD are probably two different pathological entities.