Methods: A total of 180 patients (168 males, 12 females; mean age: 69.9±7.4 years; range, 46 to 88 years) who underwent elective endovascular aneurysm repair between June 2016 and September 2021 were retrospectively analyzed. According to the proximal infrarenal aortic neck diameter, the patients were divided into two groups: Group 1 (<25 mm; normal aortic neck) and Group 2 (≥25 mm; pre-aneurysmatic aortic neck). Patient characteristics, proximal infrarenal aortic neck diameter measurements with computed tomography angiography, and clinical outcomes were recorded. The primary endpoint was to assess post-endovascular aneurysm repair aortic neck dilatation, mortality, endoleaks, overall survival, type 1a endoleaks-free survival, and eventfree survival regarding the groups.

Results: There was no statistically significant difference in early mortality (p=0.55) and type 1a endoleak incidence between the groups (p=0.55). In Group 1, the mean change in diameter A (proximal infrarenal level) was 2.89±1.74 mm (p=0.01), and it was 2.31±2.1 mm in diameter B (proximal pre-aneurysm-sac level) (p=0.01). The mean change in Group 2 was 2.8±3.4 mm for diameter A (p<0.01) and 2.22±2.3 mm for diameter B (p<0.01). Aortic neck dilatation rates were similar between the groups (p=0.82 for diameter A; p=0.78 for diameter B). The five-year survival, event-free survival, and type 1a endoleak-free survival were also similar (p=0.54, p=0.26, p=0.24, respectively).

Conclusion: Our study results showed that patients with <25 mm and ≥25-mm aortic neck diameters had similar mid-term results and aortic neck dilatation ratio. Endovascular aneurysm repair outcomes can be improved with careful patient and graft selection, and early intervention for complications.