Intra-aneurysmal hemodynamics in a large middle cerebral artery aneurysm with wall atherosclerosis

The remodeling of arterial extra-cellular matrix induced by hemodynamic stimuli is involved in the process of atherosclerosis in the carotid and cerebral arteries. Scarce information is available on the relationship between atherosclerotic changes in brain aneurysms itself and its intra-aneurysmal hemodynamics.

Surgical exploration of a large MCA aneurysm depicted extensive atherosclerotic changes in the aneurysm wall. Computational tomographic angiography of this aneurysm was used to create an in vitro aneurysm model. This model was used to perform intra-aneurysmal flow measurement using particle imaging velocimetry and LDV. Intra-aneurysmal hemodynamic pattern with wall shear stress distribution was compared between areas with and without atherosclerotic changes.

No high oscillation of wall shear stress was observed on the atherosclerotic plaque area. However, the magnitude of wall shear stress tended to be higher in the area without atherosclerotic changes than the area with those changes (P < .001). There was no atherosclerotic change at the aneurysm inflow zone, where relatively fast flow velocity and higher magnitude of wall shear stress was noted.

This single case of atherosclerosis in an aneurysm shows some similarity in hemodynamic values observed in cases of carotid atherosclerotic plaques.