Research
Acute Ischemic Stroke Modeling
Acute ischemic stroke (AIS), the result of embolic occlusion of a cerebral artery, is responsible for 87% of the 6.5 million stroke-deaths each year. Despite improvements in stent-retriever and aspiration devices, 80% of eligible AIS patients will either die or suffer a major disability. In order to improve patient outcomes, the underlying biomechanical mechanisms governing the removal of blood clots from cerebral arteries need to be better understood and new catheter-based therapies developed. We are utilizing both computational and experimental models of AIS to investigate the effects of patient-specific geometries, blood and clot properties, and hemodynamic conditions on successful clot removal.
Blood Pump Modeling
In order to simulate hemodynamics within centrifugal blood pumps and to predict pump hemolysis and/or thrombosis, CFD simulations must be thoroughly validated against experimental data. The Food and Drug Administration's (FDA) benchmark centrifugal blood pump and its database of experimental data were first used to thoroughly validate CFD simulations. This computational framework is currently being used to evaluate other blood pump designs and for predicting embolus transport to the cerebral arteries.
Thrombosis and Thrombolysis
Anti-platelet, anticoagulant, and thrombolytic agents are used for the prevention and treatment of blood clots. Systemic thrombolysis is primary treatment option for deep vein thrombosis (DVT), pulmonary embolism (PE), acute myocardial infarction (AMI), and acute ischemic stroke (AIS). Due to its intravenous introduction and short half-life, these drugs are rapidly removed from the circulation and their thrombolytic effect is quickly lost. New studies, however, have investigated local delivery in combination with mechanical thrombectomy but without knowledge of their effect on the clot itself. Therefore, we are investigating blood clot composition, their viscoelastic mechanical properties, and how they are affected by these drug therapies.
Hemocompatibility of Blood Contacting Biomaterials
Determining the interactions between cardiovascular device biomaterials and blood cells is important for predicting their thrombosis potential and how they will behave in vivo. We are currently investigating the hemocompatibility of nitinol, a shape-memory alloy commonly used in implanted stents and in stent retriever thrombectomy devices using custom-designed mechanical testing equipment and confocal and scanning electron microscopy. Additional work, is being done in collaboration with Dr. Wei Wang, from UTK Mechanical Engineering, to develop novel nitinol surface modifications for specific cardiovascular applications.
Blood Flow in Congenital Heart Disease
In the pediatric population, congenital heart disease affects over 36,000 newborns annually in the United States with few surgical options and a lack of mechanical cardiovascular support devices available to them. As part of the design process for developing devices, an improved understanding of pediatric blood flow and its influence on device induced complications including thrombosis and hemolysis is needed. Additionally, the role of altered patient hemodynamics in adverse pulmonary vascular remodeling are not well understood. we are looking to utilize computational modeling to help aid in new device design and surgical planning.
