OBJECTIVE: We aimed to investigate the changes in aorta size, the factors affecting size changes in patients with acute blunt traumatic aortic injury and to evaluate the adequacy of the current 120% thoracic endovascular aortic repair graft oversizing policy. DESIGN AND METHODS: This retrospective review study was conducted using the prospectively collected medical records of 45 patients (mean age: 53.5 years, male: 39 patients) with blunt traumatic aortic injury treated at a level 1 trauma center between 2012 and 2021. Aortic diameter was measured by computed tomography angiographic images at four different levels [ascending aorta (A), isthmus (B), descending thoracic aorta (C), and infrarenal aorta (D)] on arrival and follow-up (median time interval, 13 days). Associated factors including patient characteristics and hemodynamic parameters on arrival and follow-up were collected to determine their influence on changes in the aorta. RESULTS: The mean diameter of all four aortic levels increased on follow-up computed tomography compared to initial computed tomography (A: + 11.77%, B: + 10.19%, C: + 7.71%, D: + 12.04%). Patient age and injury severity score influenced changes in the diameter of the ascending aorta (P <
0.05). Patient age and blunt traumatic aortic injury grade were significantly associated with changes in the infrarenal aortic diameter (P <
0.05). Three cases of type 1 endoleak were observed at follow-up but all were spontaneously resolved without further intervention at next computed tomography follow-up. CONCLUSIONS: In patients with acute blunt traumatic aortic injury, aortic diameter is significantly smaller by about 10% under shock and is not considered a basis for oversizing the currently implemented 120% thoracic endovascular aortic repair graft sizing. However, in young patients under the age of 40, the change is significantly large and subsequent computed tomography follow-up is required.