Initiation and Progress of a Basilar Artery Aneurysm under Normal and Hypertensive Blood Pressure Conditions

The mechanics of cerebral aneurysm pathogenesis, evolution and rupture are not yet well understood. Thispaper presents a numerical investigation of the initiation and growth of a saccular cerebral aneurysm in a 3D model ofthe basilar artery bifurcation under normal and hypertensive blood pressure. The arterial wall was assumed to beelastic, isotropic, incompressible and homogeneous. The flow was assumed to be laminar, Newtonian, andincompressible. The fully coupled fluid and structure models were solved with the finite elements package ADINA 8.2.The pressure, wall shear stress, effective stress and deformation distributions in a normal and a hypertensive bloodpressure conditions have been compared with those of a healthy basilar artery in a normal condition. The modelpredicts aneurysm growth and shows that the combination of two independent mechanisms, are indeed of importance tothe process of initiation and progression of a cerebral aneurysm: first, the malfunction of the endothelial cell layer andthe corresponding smooth muscle cell-related loss of vascular tone and second the fiber-related arterial wallremodeling mechanism. Although the first mechanism is important to the inception of the disease, for substantialaneurysm growth to occur, the second mechanism is pivotal.

Initiation and Progress of a Basilar Artery Aneurysm under Normal and Hypertensive Blood Pressure Conditions Keywords:

Cerebral aneurysm , basilar artery , pathogenesis , hypertension , fluid structure interaction (FSI)