Hemodynamic quantication of aneurysms after treatment with flow diversion device

I. LARRABIDE; M. AGUILAR; H. MORALES; A. J. GEERS; D. RUFENACHT; A. F. FRANGI

Shangai

Simposio; 8th International Interdisciplinary Cerebrovascular Symposium; 2011

Department of Neurosurgery, Shanghai Hospital

Purpose: A variety of new alternatives for endovascular treatment of intracranial aneurysms have appeared. Still, the effect of some of these treatments on local hemodynamics is not fully understood. In the current study, we present the results obtained for a series of 23 intracranial aneurysms virtually treated with a flow diversion (FD) device.Materials and Methods: A set of 23 aneurysms were selected for virtual treatment with FD. For this group, we have 10 (43%) small, 9 (39%) medium, and 4 (17%) large/giant aneurysms. CFD simulations were created for pre- and post-treatment conditions. Regarding the shape of the aneurysms, 65% were saccular and 35% were fusiform. Hemodynamic alterations due to the placement of flow diverters were evaluated for two variables: 1) 90th percentile WSS in the aneurysm dome (WSS90), and 2) average flow velocity in the aneurysm (van). Firstly, the aneurysms were analysed by size (i.e, small, medium and large/giant). Secondly, aneurysms were grouped by shape (either fusiform or saccular).Results: Size dependent, we observed larger decreases in WSS90 for small aneurysms (small = 73%, medium = 65% and large/giant = 64%). The decrease in van was independent of aneurysm size (small = 63%, medium = 59% and large/giant = 62%). When analyzing by shape, for saccular aneurysms, slightly larger decreases in both WSS90 (saccular = 73%, fusiform= 65%) and van (saccular = 64%, fusiform = 59%) were observed.Conclusion: Clinical success of flow diverters may be explained in part by there effect on flow changes in the aneurysm. CFD analysis of flow diverter effects shows with current stent designs significant decrease  (p<0.01) of average velocity in the aneurysm and of the 90th percentile WSS. The effect seem to be more important for smaller sized  and saccular than for fusiform and large sized aneurysms, respecrtively.