TY - GEN
T1 - A biomechanics-based rupture potential index for abdominal aortic aneurysm risk assessment
T2 - Demonstrative application
AU - Vande Geest, Jonathan P.
AU - Di Martino, Elena S.
AU - Bohra, Ajay
AU - Makaroun, Michel S.
AU - Vorp, David A.
PY - 2006/11
Y1 - 2006/11
N2 - Abdominal aortic aneurysms (AAAs) can typically remain stable until the strength of the aorticwall 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.
AB - Abdominal aortic aneurysms (AAAs) can typically remain stable until the strength of the aorticwall 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.
KW - Abdominal aortic aneurysm
KW - Rupture
KW - Strength
KW - Stress
UR - http://www.scopus.com/inward/record.url?scp=34447619874&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=34447619874&partnerID=8YFLogxK
U2 - 10.1196/annals.1383.046
DO - 10.1196/annals.1383.046
M3 - Conference contribution
C2 - 17182918
AN - SCOPUS:34447619874
SN - 1573316571
SN - 9781573316576
T3 - Annals of the New York Academy of Sciences
SP - 11
EP - 21
BT - The Abdominal Aortic Aneurysm
PB - Blackwell Publishing Inc.
ER -