Modeling hemodynamics in unruptured intracranial aneurysms under varied blood pressure conditions: An in silico study

Chronic hypertension is a significant risk factor for intracranial aneurysm (IA) formation, growth, and rupture. This work aims to predict the hemodynamics in unruptured IAs and investigate the impact of aneurysm necking and bulging, along with hypotension and hypertension on the same. We simplified a patient-specific IA geometry from the literature and employed two patient-specific velocity profiles in our three-dimensional unsteady computational fluid dynamics simulations. The blood is modeled as Newtonian, and the blood vessels are non-deforming. The fast Fourier transform study reveals that the frequency in the parent artery has decreased by a factor of 40 within the aneurysm geometry. Velocity waveforms with higher pulsatility indexes, common among young adults, pose more risk factors, such as high frequency and higher wall shear stress (WSS), and are aggravated more by hypertension in patients suffering from aneurysms. This computational study lays the groundwork for improving risk assessment and treatment planning for patients with unruptured aneurysms in varying systemic pressure conditions. Hypertension increases WSS and flow dynamics frequency, raising risks of aneurysm rupture, while hypotension promotes stagnation zones, raising risks of thrombus formation. Aneurysm necking and bulging significantly alter flow patterns, correlating geometry with unique vortex modes and maximum WSS. The developed flow regime map aids in diagnosing and treating aneurysms under varying conditions. High pulsatility indices, particularly in younger individuals, amplify risks, highlighting the need for tailored management strategies.