• Vascular Annual Meeting
• Future Meeting Dates
• Past Meeting Information
• Contact Us

Does Peak Wall Stress Correlate Better with Abdominal Aortic Aneurysm Expansion than Aortic Diameter?

Mohd Norhisham Azmi Abdul Rahman, Michael Heng, Michael Fagan, John Greenman, Peter McCollum, Ian Chetter.
University of Hull, Hull, United Kingdom.

OBJECTIVES: Level 1 evidence clearly supports ultrasound surveillance in abdominal aortic aneurysm (AAA) <5.5 cm in maximum AP diameter, with scanning interval set according to the size of aneurysm. Larger aneurysms tend to expand at a greater rate than smaller aneurysms. However, AAA expansion is variable and difficult to predict, and size may not always predict expansion. We aimed to assess whether peak wall stress (PWS) measured through finite element analysis, correlates better with AAA expansion.

METHODS: 57 patients, 46 men, median age of 76.5 (range 54-93) years, under AAA surveillance were studied. All patients underwent abdominal CT scan to characterise the aneurysms and measure PWS through finite element analysis. Expansion rates were derived from sequential ultrasound scans. Correlation between PWS and expansion rate, as well as between size and expansion rate was analyzed using Pearson Correlation test (SPSS for Windows v14).

RESULTS: Mean aortic diameter was 4.83±0.70 cm and mean PWS was 0.42±0.12 MPa. Mean expansion rate was 0.32±25 mm/month. Pearson Correlation between PWS and AAA expansion rate was 0.30 (p=0.02). Pearson Correlation between aorta AP diameter and AAA expansion rate was 0.20 (p=0.14).

CONCLUSIONS: In this cohort of patients the correlation between PWS and AAA expansion rate is statistically significant and such correlation is failed to be demonstrated with initial AAA diameter and this deserves further investigation.

AUTHOR DISCLOSURES: M. Abdul Rahman, None; M. Heng, None; M. Fagan, None; J. Greenman, None; P. McCollum, None; I. Chetter, None.