Research Projects

Every year a large number of patients undergo heart valve replacements. It is well reported that mechanical heart valves yield better longevity compared to the bioprosthetic one. However, issues like thromboembolisms and blood cell deformations are associated with mechanical heart valves and patients are put under regular check-up and subsequent medication through their entire life span. A tool for prediction of patient specific performance of the replaced heart valves and assessing the resulting stresses on arterial lumen and blood cells can be of help to medical practitioners. The proposed research will focus on investigating the micro-scale blood cell dynamics due to the macro-scale shear and turbulent stresses created by the operation of a mechanical heart valve in the cardiac domain with viscoelastic walls. Rheological changes in the blood property due to the cell deformation and interactions will be assessed and coupled with the large-scale computational fluid dynamics (CFD) calculations of the proposed cardio-vascular flows. A multi-scale simulation framework will be used for that and patient specific medical images will be considered to reconstruct the computational domain. Effects of arterial narrowing and wall hardening in the aortic flow structures will be studied and wall shear stress levels will be reported. The computational complexities in the proposed multi-scale simulation coupling the aortic fluid dynamic calculations with blood cell dynamics will be handled using parallel computing infrastructure with GPGPU accelerators. The present project will develop a numerical tool to study the fluid-structure interaction over the mechanical heart valves using immersed boundary method. A large-eddy simulation technique will be deployed to model the small scale turbulent motions while the large energy carrying structures in the aorta will be resolved directly. Different mechanical valve configurations will be tested and the performance metrics will be compared. Comparisons will be made with bioprosthetic valves which has less life-span but better potential of preventing micorembolism formation. Platelet activation due to turbulent stresses will be studied numerically to predict the formation of thromboembolisms. A multi-scale model will be used to observe the dynamics of red blood cells and its interaction with platelets. The potential cell damage due to hemolysis under the turbulent stresses during operation of the mechanical valves will be assessed. Open-source software to predict patient specific performance of mechanical heart valves will be developed through this project which will help the clinicians to choose the right heart valve and optimize the operational parameters.