Background: The maximum axial diameter (MAD) of a fusiform abdominal aortic aneurysm (AAA) is an indicator of the risk of expansion or rupture. Apart from smoking and MAD itself, few expansion risk factors have been reported. In this study, we investigated expansion risk factors for AAA.
Methods and Results: This retrospective cohort study included 176 patients who attended Tohoku University Hospital with infrarenal fusiform AAA. AAA expansion rate was determined on multidetector computed tomography, and the correlations between expansion rate and the clinical data were analyzed. The median expansion rate was 2.405 mm/year. On univariate analysis, a significant positive correlation with expansion rate was observed for the initial MAD (P<0.001) and significant negative correlations for oral angiotensin receptor blocker usage (P=0.025), height (P=0.005), body weight (P=0.017), total cholesterol (P=0.007), low-density lipoprotein cholesterol (P=0.004), and HbA1c (P=0.037). On logistic regression analysis, significant positive associations with expansion rate were observed for initial MAD (P< 0.001) and oral steroid usage (P=0.029) and a negative association for height (P=0.041).
Conclusions: Oral steroid usage is an important risk factor for AAA expansion, independent of other risk factors of atherosclerosis and MAD.