Shift in Patient Demographics of Open Thoracoabdominal Aortic Aneurysm Repair Patients in the Endovascular Era

<b>Background/Objectives</b>: Open thoracoabdominal aortic aneurysm (TAAA) repair remains essential despite expanded endovascular options, yet the contemporary open-surgery case-mix has shifted as minimally invasive therapies became widespread. The objective was to evaluate temporal changes in patient demographics, pathology, and perioperative outcomes of open TAAA repair across two decades. <b>Methods</b>: Retrospective, cross border cohort of all open TAAA repairs performed at two high-volume tertiary centers (Aachen, Germany; Maastricht, Netherlands) from 2000-2024. Patients were stratified into Early Era (2004-2013) and Late Era (2014-2024). Primary endpoints were shifts in demographics and perioperative mortality/morbidity; secondary endpoints included major complications (spinal cord ischemia, acute kidney injury, pulmonary and cardiac events). <b>Results</b>: Among 577 open repairs, 376 (65.2%) occurred in the Early Era and 201 (34.8%) in the Late Era, with annual volumes declining to <12 cases/year after 2020. Late Era patients were younger (median 55.9 vs. 63.0 years, p<0.001) and had more genetic aortopathy (Marfan 26.9% vs. 11.7%, p<0.01) and post-dissection pathology (64.7% vs. 43.1%, p<0.01), alongside more prior aortic surgery (59.2% vs. 43.4%, p<0.01). Massive transfusion and incidental splenectomy decreased (37.8% vs. 54.5%, p<0.01; 5.0% vs. 14.9%, p<0.01). In-hospital mortality was similar (18.4% Late vs. 21.8% Early, p=0.34); spinal cord ischemia showed a non-significant reduction (5.5% vs. 8.0%, p=0.26); myocardial infarction decreased (1.0% vs. 4.3%, p=0.03); and ARDS increased (15.9% vs. 5.1%, p<0.01). <b>Conclusions</b>: Despite the shift towards endovascular repair and the changing demographics of patients selected for open TAAA repair, specialized centers can maintain stable outcomes through standardized protocols and concentrated expertise. The preservation of open surgical capabilities remains crucial for specific patient populations, emphasizing the need for a balanced approach that integrates both open and endovascular techniques to provide optimal, individualized care.