Morphological risk of acute type A aortic dissection in the mildly to moderately dilated aorta.

Objectives: This study aimed to analyse and determine the role of aortic length and curvature in the pathogenesis of acute type A aortic dissection (ATAAD) with ascending aortic diameters (AADs) <5 cm.

Methods: We reviewed the clinical and imaging data of patients with ATAAD (n = 201) and ascending aortic dilation (n = 83). Thoracic aortic bending index (TABI) was used to quantify aortic curvature and analyse its role in ATAAD below the diameter risk threshold.