Purpose To investigate the relationship between the intra-aneurysmal hemodynamic conditions and the mechanical properties of the wall in human aneurysms.

Methods A total of six unruptured aneurysms were analyzed. Computational fluid dynamics (CFD) models were constructed from pre-operative 3D rotational angiography images. The aneurysms were clipped and the domes were resected and mechanically tested to failure with a uniaxial testing system under multi-photon microspopy. Linear regression analysis was performed to explore possible correlations between hemodynamic quantities and the failure strain and stiffness of the wall.

Results The failure strain was negatively correlated to aneurysm inflow rate (p = 0.025) and mean velocity (p = 0.042). It was also negatively correlated to mean wall shear stress, oscillatory shear index and measures of the complexity and instability of the flow, however these trends did not reach statistical significance. The wall stiffness was positively correlated to inflow rate (p = 0.056), mean velocity (p = 0.04) flow instability (p = 0.02), flow complexity (p = 0.055), wall shear stress (p = 0.017) and oscillatory shear index (p = 0.021).

Conclusions Larger flow activity within intracranial aneurysms characterized by larger inflow rates, mean velocity, more complex and unstable flow structures, higher wall shear stress and oscillatory shear index seem to be associated with weaker and stiffer aneurysm walls.

Disclosures C. Putman: None. J. Cebral: 1; C; NIH #R21 NS080031. X. Duan: 1; C; NIH #R21 NS080031. B. Chung: 1; C; NIH #R21 NS080031. K. Aziz: None. A. Robertson: 1; C; NIH #R21 NS080031.