Background: There is little information about the anatomical characteristics and relationship between ruptured and unruptured abdominal aortic aneurysm (AAA).

Objective: The present study was to determine the anatomical differences between the two groups as assessed with multi-detector computed tomographic angiography (CTA).

Materials and Methods: A retrospective review of all the patients diagnosed with AAA that underwent CTA before aortic repair were performed with matching between ruptured and unruptured groups for age and gender. Patient characteristics, and morphological data of aneurysmal and non-aneurysmal parts on CTA images were reviewed.

Results: Ninety-six patients in each group were matched. The ruptured group had significantly lower systolic blood pressure (p=0.027), and higher blood creatinine (p=0.006). In the aneurysm part, maximal aneurysmal diameter was significantly larger in the ruptured group at 7.8 cm versus 6 cm (p<0.001), as well as the larger lumen diameter (p=0.006), longer aneurysmal length (p=0.005), shorter aneurysmal neck length (p=0.009), and thicker maximal thrombus thickness (p<0.001). In the non-aneurysmal part, the aortic diameter of the ruptured group was significantly larger in every location. Multivariate analysis indicated that maximal aneurysmal diameter, non-aneurysmal part of the infrarenal aortic diameter, aneurysmal neck length, and current smoking status remained significant variables for ruptured AAAs.

Conclusion: Ruptured AAAs had shorter aneurysmal neck length and larger diameter of both aneurysmal and non-aneurysmal parts of AAA than unruptured group.

Keywords: Abdominal aortic aneurysm; CT angiography

DOI: doi.org/10.35755/jmedassocthai.2021.09.12998

Received 17 May 2021 | Revised 28 June 2021 | Accepted 29 June 2021