Abstract W P74: The Effects of Hypertension and Hypotension on Patient-Specific Computer Modeled Clipping of an ICA Aneurysm

Abstract

INTRODUCTION: Studies suggest that blood pressure changes alter the potential for development and rupture of aneurysms. This study aims to distinguish hemodynamic differences between hypertensive, hypotensive, and normotensive milieus in 3D patient-specific simulated clipping in various clip orientations. MATERIALS AND METHODS: A patient-specific 3D-geometric mesh model of a terminal ICA aneurysm was reconstructed with Mimics 17 (Materialise) from angiographic data. The 3D-model was modified in SolidWorks to simulate clip configurations. The volumetric flow rate waveform of the ICA in a patient was scaled to a 1.5 Pa cycle averaged WSS at the ICA; flow rate was changed by +/-25% to simulate hypertensive and hypotensive events. CFD was carried out in Fluent (ANSYS). WSS of the aneurysm in various clipping orientations were compared. RESULTS: The results of the CFD analysis of increased flow rates demonstrate clip-oriented-based differences in WSS that contribute to the potential for growth of aneurysm residuals. When pressures were scaled to hypo- or hypertensive pressure profiles, a qualitatively proportional change in WSS was identified. The patterns of WSS on the complete clipping differed from those on the incomplete clipping, with a shift in the regions of elevated WSS to areas of residual dome. CONCLUSIONS: The results suggest that changes in blood pressure contribute to the hemodynamic milieu proportionately. Though proportional, the area of impingement is shown to expand to areas of known abnormal histology, namely that of the residual dome. These data suggest that control of blood pressure may be paramount in the short and long term postoperative care of these patients.