A Biomechanics‐Based Rupture Potential Index for Abdominal Aortic Aneurysm Risk Assessment
- 1 November 2006
- journal article
- research article
- Published by Wiley in Annals of the New York Academy of Sciences
- Vol. 1085 (1), 11-21
- https://doi.org/10.1196/annals.1383.046
Abstract
Abdominal aortic aneurysms (AAAs) can typically remain stable until the strength of the aortic wall is unable to withstand the forces acting on it as a result of the luminal blood pressure, resulting in AAA rupture. The clinical treatment of AAA patients presents a dilemma for the surgeon: surgery should only be recommended when the risk of rupture of the AAA outweighs the risks associated with the interventional procedure. Since AAA rupture occurs when the stress acting on the wall exceeds its strength, the assessment of AAA rupture should include estimates of both wall stress and wall strength distributions. The present work details a method for noninvasively assessing the rupture potential of AAAs using patient-specific estimations the rupture potential index (RPI) of the AAA, calculated as the ratio of locally acting wall stress to strength. The RPI was calculated for thirteen AAAs, which were broken up into ruptured (n= 8 and nonruptured (n= 5) groups. Differences in peak wall stress, minimum strength and maximum RPI were compared across groups. There were no statistical differences in the maximum transverse diameters (6.8 ± 0.3 cm vs. 6.1 ± 0.5 cm, p= 0.26) or peak wall stress (46.0 ± 4.3 vs. 49.9 ± 4.0 N/cm2, p= 0.62) between groups. There was a significant decrease in minimum wall strength for ruptured AAA (81.2 ± 3.9 and 108.3 ± 10.2 N/cm2, p= 0.045). While the differences in RPI values (ruptured = 0.48 ± 0.05 vs. nonruptured = 0.36 ± 0.03, respectively; p= 0.10) did not reach statistical significance, the p-value for the peak RPI comparison was lower than that for both the maximum diameter (p= 0.26) and peak wall stress (p= 0.62) comparisons. This result suggests that the peak RPI may be better able to identify those AAAs at high risk of rupture than maximum diameter or peak wall stress alone. The clinical relevance of this method for rupture assessment has yet to be validated, however, its success could aid clinicians in decision making and AAA patient management.Keywords
This publication has 27 references indexed in Scilit:
- Size and location of thrombus in intact and ruptured abdominal aortic aneurysmsJournal of Vascular Surgery, 2005
- A mathematical model for the growth of the abdominal aortic aneurysmBiomechanics and Modeling in Mechanobiology, 2004
- A Comparative Study of Aortic Wall Stress Using Finite Element Analysis for Ruptured and Non-ruptured Abdominal Aortic AneurysmsEuropean Journal of Vascular and Endovascular Surgery, 2004
- The risk of rupture in untreated aneurysms: The impact of size, gender, and expansion rateJournal of Vascular Surgery, 2003
- Mechanical properties of abdominal aortic aneurysm wallJournal of Medical Engineering & Technology, 2001
- Growth of Thrombus may be a Better Predictor of Rupture than Diameter in Patients with Abdominal Aortic AneurysmsEuropean Journal of Vascular and Endovascular Surgery, 2000
- Abdominal Aortic Aneurysm Wall Mechanics and their Relation to Risk of RuptureEuropean Journal of Vascular and Endovascular Surgery, 1999
- Growth rates and risk of rupture of abdominal aortic aneurysmsBritish Journal of Surgery, 1998
- Biomechanical factors in abdominal aortic aneurysm ruptureEuropean Journal of Vascular Surgery, 1993
- The influence of aorta-aneurysm geometry upon stress in the aneurysm wallJournal of Surgical Research, 1987