BACKGROUND AND AIMS: To investigate whether, alongside aortic dilatation, ascending aortic (AA) elongation is associated with the increased risk for aortic dissection. METHODS: This retrospective study included patients treated for Stanford type A aortic dissection (n = 102) in Kuopio University Hospital between 2009 and 2022, patients with AA dilatation (maximal diameter >
40 mm) (n = 134), and healthy controls (n = 191). AA length and dimensions were measured from aortic computed tomography angiography (CTA) images. AA length was defined as the distance between the aortic annulus and the origin of the brachiocephalic trunk. RESULTS: After adjusting the AA length to the patients' age, height, body surface area (BSA), sex, and maximal diameter, the dissected aortas were 14 mm longer than in the healthy controls and 5 mm longer than in the dilated non-dissected aortas (p <
0.001). The dilated non-dissected aortas were 8 mm longer than in the healthy controls (p <
0.001). In the dissection cohort, 25/102 (25%) patients had maximal AA diameter <
55 mm and 16/102 (16%) patients had maximal AA diameter ⩾ 55 mm together with AA length >
110 mm. By combining 110 mm AA length and <
55 mm diameter, 58% of the dissection patients would have been identified instead of using solely AA diameter ⩾ 55 mm as a cut-off criterion, based on which only 33% patients met the indication for elective surgery. CONCLUSION: AA length seemed to have an association with acute type A dissection, and therefore, it could be an additional tool in identifying patients who may benefit from preventive aortic surgery.[Formula: see text].