Abstract 11948: Accumulation of Calcium in Aortic Wall is Negatively Correlated with The Progression of Abdominal Aortic Aneurysm

Abstract

Background: Some cohort studies have shown the negative correlation between the formation/progression of abdominal aortic aneurysm (AAA) and diabetes mellitus in which calcification of arteries can be often observed. But the mechanism for this negative correlation remains unknown. Moreover, there has been no report to demonstrate whether calcium deposition in the aortic wall is related to AAA progression.

Method: We conducted a retrospective cohort study on 869 patients who underwent elective repair for the infrarenal AAA in multicenter in Tokyo from 2003 through 2011. This analysis was subject to the patients having at least 2 follow-up CT scan data before AAA repair. The patients with saccular, traumatic or inflammatory aneurysm, Marfan syndrome and short followed-up period (<90 days) cases were excluded. The expansion rate of AAA was examined by CT scan. The accumulated calcium in the aortic wall was evaluated by measuring the rate of total surface area of calcium deposition in AAA based on the 3D-CT imaging with volume rendering technique. Detectable calcium was defined as a calcium score > 130-HU threshold. Student's t-test and multiple logistic regression analysis were performed.

Results: The 517 cases remained after the exclusions shown above. The average age was 73 ± 8 years. The rate of total calcium area in AAA was statistically lower in patients with acute expansion of AAA (> 5mm/year), compared to patients with non-acute expansion of AAA (< 5mm/year) (3.2% vs. 6.2%, p<0.01). Patients with high rate of calcium deposition (≧ 5%) had significantly lower risk of AAA acute-expansion compared with patients with low rate of calcium deposition (<5%), even after adjusting for age, gender, hypertension, diabetes, smoking and chronic obstructive pulmonary disease (HR0.32, 95%CI 0.11-0.90, P=0.032).

Conclusion: The extent of accumulated calcium in the aortic wall was negatively correlated with AAA expansion rate. To establish the measuring method for the calcium deposition in the aortic wall might be useful for prediction of AAA progression.