Finite element analysis in symptomatic and asymptomatic abdominal aortic aneurysms for aortic disease risk stratification.

BACKGROUND: Advanced biomechanical models can provide additional information concerning rupture risk in abdominal aortic aneurysms (AAA). Here we evaluated the predictive value of finite element analysis (FEA) to assess AAA rupture risk.

METHODS: In a case-control study, we compared FEA parameters in a group of symptomatic AAA (sAAA) patients, considered as a high risk of rupture group, with FEA parameters in asymptomatic AAA patients (aAAA).

RESULTS: We included 15 sAAA and 28 aAAA patients matched for age- and maximum diameter diagnosed with infrarenal non-ruptured AAA at our centre between 2009 and 2013. Mean (standard deviation) age was 75 (69) years and maximum diameter was 77 (17) mm. Peak wall stress (PWS) was significantly higher in sAAA patients than in aAAA patients (354.3 (139.6) kPa vs 248.6 (81.9) kPa;P=.001). The C statistic for the ROC curve based on PWS was 0.748 [95% CI 0.592-0.903; P=.008]. CART analysis classified patients into high and low PWS groups. The high-PWS group (>305.15 kPa; n=15) had a higher incidence of sAAA (33.3% aAAA, 66.7% sAAA) than the low-PWS-group (≤305.15 kPa; n=28. 82.1% aAAA, 17.9% sAAA).

CONCLUSIONS: In conclusion, PWS was significantly higher in sAAA patients. Measuring PWS may help estimate the individual rupture risk in patients with AAA, but larger studies are needed to confirm our results.