This clinical trial is focused on studying the treatment of an abdominal aortic aneurysm, a condition where a large blood vessel in the abdomen becomes enlarged and can potentially burst. The treatment being tested involves the use of allogeneic adipose-derived mesenchymal stem cells, which are special cells taken from donated fat tissue and expanded in a lab. These cells are then injected into the aneurysm area to see if they can help stabilize it.

The purpose of the study is to evaluate the safety and feasibility of using these stem cells in patients who are undergoing a procedure called endovascular surgical repair, which is a less invasive surgery to fix the aneurysm. Participants in the study will receive either the stem cell treatment or a placebo. The study will monitor participants for any side effects related to the procedure or the stem cells, as well as any major heart or brain-related events within a year after treatment.

Throughout the study, the size of the aneurysm will be checked using imaging tests like CT scans and Doppler echo. The study will also compare the results to past patients who did not receive the stem cell treatment. Other aspects being observed include the movement of the stent used in the repair, any leaks, the need for additional surgeries, hospital admissions, and changes in quality of life. The study is expected to continue until early 2026.