CFD Simulations of the Carotid Artery to Investigate the Connection between Blood Flow Patterns and Stroke

One out of every twenty deaths in the United States are caused by strokes, eighty seven percent of which are ischemic. Blood flow in the carotid artery may be obstructed due to carotid artery stenosis when plaque develops, narrows, and hardens the arteries, resulting in an increased potential for stroke and transient ischemic attacks. Carotid endarterectomies can be performed to aid the blood flow process or to remove plaque directly in patients with high levels of stenosis. However, this surgery is invasive and comes with numerous risks, making it difficult to assess this treatment plan in asymptomatic or low-risk patients. Additional predictive measures are necessary to avoid invasive surgeries and to aid medical care decisions in the prevention of stroke. The goal of this project is to investigate the velocity profiles and pressure gradients in the carotid artery of patient-specific geometries to better understand their connection to stroke. Computational Fluid Dynamics (CFD) simulations of the carotid artery allow for the intersection of medicine and engineering. Blood flow through the carotid artery was analyzed for these flow characteristics using finite-element analysis. CFD is advantageous over relying solely on both ultrasound and Computerized Tomography Angiography (CTA) data as it allows for the study of each patient’s unique blood flow patterns and can provide further insight into parameters that may influence the risk for stroke. In Phase I of this project, the ultrasound data of forty-five patients was provided by the Department of Neurosurgery at the University of Rochester Medical Center where the stroke outcome of each patient was known. The simulation results indicate that regions of high pressure and irregular velocity gradients near the carotid wall correspond to an increased potential for stroke. The results from 45 patients were scrutinized to determine whether the patients who experienced a stroke exhibited these flow patterns and those without a stroke outcome displayed contrasting flow patterns. The confirmation of this analysis leads to Phase II of the project where an additional 45 patients will be investigated in a double-blind study, in which the patient outcome is unknown until after the CFD simulations and analysis are completed.