Abstract 1145: A Computational Fluid Dynamics Analysis Of Hemodynamic Differences In Patients With High Grade Asymptomatic Carotid Artery Stenosis

Abstract

Introduction: Current assessment/management of internal carotid artery (ICA) stenosis is based on estimation of percentage (%) stenosis which does not account for trans-lesional flow, pressure gradient (PG), wall shear stress (WSS), or oscillatory shear index (OSI). Computation fluid dynamics (CFD) can be used to characterize such indices. Hypothesis: We hypothesize that patients asymptomatic >70% ICA stenosis will have hemodynamic differences that are independent of % stenosis. Aims: Evaluate hemodynamic indices in patients with asymptomatic >70% ICA stenosis via CFD. Methods: Patients with asymptomatic >70% ICA stenosis were included. 3D time-of-flight (TOF) and phase-contrast (PC) magnetic resonance imaging (MRI) sequences were obtained. CRIMSON was used to generate CFD models containing the carotid artery (CCA), ICA, and external carotid artery (ECA). PC MRI-derived flow waveforms were prescribed to the CCA and ECA. The ICA outlet was coupled to a three-element Windkessel model. Blood was modeled as an incompressible Non-Newtonian fluid with a dynamic viscosity of 0.004 kg m –1 s –1 and a density of 1,060 kg m -3 . Incompressible Navier-Stokes equations were used to solve for velocity and pressures. Results: Eight patients (average age 73.8 years, 62.5% male) with asymptomatic high-grade ICA stenosis (62.5% left) were included. Hypertension (87.5%), tobacco use (87.5%), and hyperlipidemia (75%) were common. Most patients were medically optimized with anti-hypertensive (100%), statin (87.5%), and aspirin (87.5%). Three patients (37.5%) underwent ICA intervention.. Mean peak systolic velocity was 406 cm/s and mean end-diastolic velocity was 127 cm/s. There was large variability in trans-lesional ICA flow, PG, WSS, and OSI (Table 1). Conclusions: Asymptomatic patients with the same % stenosis have differences in trans-lesional ICA flow, PG, WSS, and OSI. Future work is needed to determine the prognostic value of such differences.