Study of aortic index of tortuosity in type A aortic dissection

Introduction The risk of type A aortic dissection (AAD) depends on the degree of aortic wall's alteration, which can result in dilatation and tortuosity. The estimate of this risk currently relies solely on measuring the diameter of the ascending aorta. Objective The purpose of this study is to ascertain that patients with AAD don’t have higher aortic tortuosity, and more liver or renal cysts. Method We analyzed aortic scans of 109 patients with AAD after surgery and 109 control patients matched on gender and age. After 3D reconstruction, the total and geometrical lengths (Ltot and Lgeo) of the different aortic segments were measured to calculate the aortic index of tortuosity (IT = Ltot/Lgeo). Results The different aortic segments of the AAD group have higher Ltot, Lgeo and IT than the control group. For the whole aorta, the mean Ltot is 527.7 ± 46.1 mm for the AAD group versus 475.8 ± 39.7 mm for the control group, i.e. 9.4% longer (P  Fig. 1 ). For the whole aorta with exclusion of the ascending part, ie non-operated aorta, the threshold value of the IT at 1.303 makes it possible to discriminate AAD patients in our population with a sensitivity of 69.7% and a specificity of 79.8%, i.e. an accuracy of 74.8% (AUC = 0.792, P  Conclusion Patients with AAD have a longer and more tortuous aorta and also more liver or renal cysts. Aortic tortuosity is favored by presence of cysts, hypertension, age and warned by diabetes. A new study is needed to confirm that the higher the Ltot, IT and the number of cysts are, the higher the risk of AAD is; and also that our threshold value of IT2 at 1.303 could be associated with the measurement of the diameter aortic for discussion of prophylactic AAD surgery.