Volumetric Abdominal Aortic Aneurysm Analysis in Post EVAR Surveillance Settings.

Introduction: Early detection of abdominal aortic aneurysms (AAA) is a mainstay of diagnosis, with Endovascular aortic repair (EVAR) emerging as the primary mode of repair. Maximum diameter measurement remains central to risk assessment; however, recent studies suggest AAA volumetric analysis may be more sensitive to true size changes. We compare the utility of volume and diameter in AAA size assessment and further investigating related clinical factors.

Methods: We retrospectively reviewed all patients who underwent EVAR at our institution between August 2017 and March 2023 with available pre- and post-operative CT angiograms. AAA total aneurysm and lumen volume were measured using semiautomatic segmentations. Maximum diameter, clinical variables were extracted from the medical record. Direct comparison of volume to diameter was completed using percent change from baseline. A subgroup of patients with long-term follow-up data (>231 days between scans) were used for additional analyses.

Results: Of 116 patients, 69 (59.5%) were included in the long-term patient cohort. Post-intervention, percent change volume and percent change diameter had a moderate positive correlation (r=0.6662), and average AAA percent change did not differ between volume and diameter (1.5% vs -1.8%, respectively; p=0.1654). Volumetric analysis was more likely to detect aneurysm sac enlargement (p=0.0315). On univariable analysis, increase in volume and diameter was associated with older age and endoleak. A diameter decrease was associated with metformin therapy.

Conclusion: Aneurysm volume is more likely to detect AAA enlargement than diameter. The benefit of early detection of high-risk aneurysms may translate to changes in surveillance and ultimately decrease aneurysm-related mortality.