Influence of gender on intraluminal thrombus of abdominal aortic aneurysms

Background: The mechanisms of formation of intraluminal thrombus (ILT) of abdominal aortic aneurysms (AAA) remain unknown. The aim of this study was to investigate the pathogenesis of AAA by analysis of ILT. Methods: We retrospectively analyzed the size of ILT in 98 consecutive patients with AAA undergoing abdominal computed tomography (CT) examination. The volume of ILT was estimated by the area ratio of ILT in CT images. Important baseline variables related to small ILT were determined using logistic-regression analysis. Results: There were two apparent peaks in the distribution of ILT ratio. Thirteen of 98 patients had negligible ILT with ratio ≤0.1. Female gender was the only patient characteristic independently significantly correlated with small ILT (odds ratio 5.214, P = 0.0096). Conclusion: Our findings provide important evidence that AAA is formed by at least two different pathogenic processes. It is likely that this difference in mechanisms may be caused partly by sex hormones.