Design of the study: single-center cross-sectional study. Population: 40 patients with aneurysm of the infra-renal abdominal aorta requiring surgical treatment by open surgery. Patients will be divided into 2 groups based on the size of the aneurysm (Group 1: 20 patients with aneurysm diameter of below 75 mm; Group 2: 20 patients with aneurysm diameter above 75 mm; patients a ruptured aneurysm can be included in both groups).