The role of geometric parameters in the prediction of abdominal aortic aneurysm wall stress.

OBJECTIVE To study the correlation between peak wall stress (PWS) and abdominal aorta aneurysm (AAA) geometric parameters in the presence of intraluminal thrombus (ILT). DESIGN Computational study using finite element analysis. MATERIAL AAA models were created by three-dimensional (3D) reconstruction of in vivo acquired computed tomography (CT) images from 19 patients. METHODS PWS was evaluated in the presence and absence of ILT. DeltaPWS% represents the percentage change in PWS in the presence of ILT. The 3D lumen centrelines were extracted, and the values of torsion, tortuosity and mean curvature were estimated. RESULTS A positive correlation was observed between DeltaPWS% and relative ILT volume (P=0.03). PWS in the presence of ILT significantly correlated only with the degree of centerline tortuosity (P=0.003) and maximum diameter (P<0.0001). The optimal predictive model for PWS in the presence of ILT was estimated to contain both maximum diameter and centreline tortuosity. CONCLUSIONS Specific geometric parameters in AAA models in the presence of ILT could serve as potential predictors of elevated PWS. PWS correlated significantly with the maximum diameter and the degree of centreline tortuosity. Centreline tortuosity may become a useful addition to maximum diameter in the decision-making process of AAA treatment.