Effects of arterial geometry on aneurysm growth: three-dimensional computational fluid dynamics study.
OBJECTIVE
Few researchers have quantified the role of arterial geometry in the pathogenesis of saccular cerebral aneurysms. The authors investigated the effects of parent artery geometry on aneurysm hemodynamics and assessed the implications relative to aneurysm growth and treatment effectiveness.


METHODS
The hemodynamics of three-dimensional saccular aneurysms arising from the lateral wall of arteries with varying arterial curves (starting with a straight vessel model) and neck sizes were studied using a computational fluid dynamics analysis. The effects of these geometric parameters on hemodynamic parameters, including flow velocity, aneurysm wall shear stress (WSS), and area of elevated WSS during the cardiac cycle (time-dependent impact zone), were quantified. Unlike simulations involving aneurysms located on straight arteries, blood flow inertia (centrifugal effects) rather than viscous diffusion was the predominant force driving blood into aneurysm sacs on curved arteries. As the degree of arterial curvature increased, flow impingement on the distal side of the neck intensified, leading to elevations in the WSS and enlargement of the impact zone at the distal side of the aneurysm neck.


CONCLUSIONS
Based on these simulations the authors postulate that lateral saccular aneurysms located on more curved arteries are subjected to higher hemodynamic stresses. Saccular aneurysms with wider necks have larger impact zones. The large impact zone at the distal side of the aneurysm neck correlates well with other findings, implicating this zone as the most likely site of aneurysm growth or regrowth of treated lesions. To protect against high hemodynamic stresses, protection of the distal side of the aneurysm neck from flow impingement is critical.
Department of Mechanical and Aerospace Engineering, Department of Neurosurgery, Toshiba Stroke Research Center, School of Medicine and Biomedical Sciences, University at Buffalo, The State University of New York, Buffalo, New York 14620, USA.
Yiemeng
Y
Hoi
Hui
H
Meng
Scott H
SH
Woodward
Bernard R
BR
Bendok
Ricardo A
RA
Hanel
Lee R
LR
Guterman
L Nelson
LN
Hopkins
D000886:Anthropometry; D002536:Cerebral Arteries / Q000033:anatomy & histology*; D006439:Hemodynamics; D006801:Humans; D021621:Imaging, Three-Dimensional; D002532:Intracranial Aneurysm / Q000503:physiopathology*; D008962:Models, Theoretical; D009333:Neck / Q000033:anatomy & histology; D012039:Regional Blood Flow; D012307:Risk Factors; D020521:Stroke / Q000503:physiopathology*