The Impact of Pre-Operative Aneurysm Diameter on Mortality After Standard and Complex Endovascular Aortic Repair.

Background: Various anatomical factors have been related to mortality after endovascular aortic aneurysm repair (EVAR). This systematic review investigated the impact of the pre-operative maximum aortic aneurysm diameter on mortality after standard and complex EVAR. Methods: The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines were followed to search the MEDLINE, EMBASE, via Ovid and CENTRAL databases, until 31st July 2025. Randomized controlled trials and observational studies were eligible if they were published between 2015 and 2025 and reported on the association of the pre-operative maximum aortic aneurysm diameter with a 30-day and midterm mortality follow-up in standard and complex EVAR patients. The Newcastle-Ottawa Scale assessed the risk of bias. The primary outcome was the impact of the pre-operative maximum aortic aneurysm diameter on 30-day mortality after standard and complex EVAR. Results: From 1182 studies, 25 were included; 19 reporting on standard (130,476) patients and six on complex EVAR (14,097) patients. A significant heterogeneity in terms of maximum pre-operative aortic aneurysm diameter threshold to identify larger aneurysms was detected. Regarding standard EVAR, eight studies evaluated the impact of the pre-operative maximum abdominal aortic aneurysm (AAA) diameter on 30-day mortality (smaller: 0.3-13.2% vs. larger: 0.7-20.8%) with conflicting outcomes. Four studies (4/8 studies; 50%) concluded that a larger diameter was related to higher 30-day mortality in patients with standard EVAR, while four showed no statistical significance. Two out of five standard EVAR studies that investigated the pre-operative AAA diameter as an independent predictor for 30-day mortality confirmed this finding. During the mid-term follow-up, ten studies showed that the pre-operative maximum AAA diameter was independently related to mortality after standard EVAR. In complex EVAR, four out of six studies showed that the 30-day mortality was higher (smaller: 0.5-7.0% vs. larger: 4.0-15.0%) in larger aortic aneurysms, including juxta-, para-, supra-renal, and thoracoabdominal aortic aneurysms. Four out of five (80.0%) studies showed that a larger diameter was an independent predictor for follow-up mortality after complex EVAR. Conclusions: The pre-operative aortic aneurysm diameter seems to be related to mortality after standard or complex EVAR. However, the impact of the pre-operative aortic aneurysm diameter on mortality seems to be more prominent in complex EVAR cases, with 80% of studies confirming this finding.