Wall stress correlates with intimal entry tear localization in Type A aortic dissection†

OBJECTIVES: The risk of aortic dissection should be assessed based not only on the aortic diameter, but also on other biomechanical parameters that have an impact on the stress in the aortic wall. This study evaluates very rare clinical scenarios of patients with both pre- and post-dissection computed tomography (CT) images and evaluates whether an increased wall stress correlates with the localization of an intimal entry tear in Type A aortic dissection. METHODS: CT-angiography images of 4 patients performed shortly prior to and after developing Type A aortic dissection were evaluated. The stress distribution in the pre-dissection aortas was evaluated using the finite elements method. Then, the areas of high stress in the pre-dissection aortas were compared to the localization of the intimal entry tears in the dissected vessels. RESULTS: In all the patients, the pre-dissection areas of high wall stress correlated with the location of the intimal tears. The highest stress was not observed in the most dilated segments of the aorta but was predominantly found in the areas of an abrupt change in the geometry of the aorta. CONCLUSIONS: Wall stress can indicate the areas susceptible to the formation of an intimal tear and subsequent aortic dissection. Stress analysis may be a valuable tool to predict the risk of aortic dissection in patients with aortic dilatation.