FLOW DYNAMIC COMPARISON BETWEEN RECESSED HINGE AND OPEN PIVOT BI-LEAFLET HEART VALVE DESIGNS

Area of Science:

• Biomedical Engineering
• Fluid Dynamics
• Computational Mechanics

Background:

• Mechanical heart valves are essential for patients with heart disease.
• Complex flow dynamics in valve hinge regions can lead to high shear stresses.
• Platelet activation, a key factor in thrombotic events, is influenced by these stresses, especially during valve closure.

Purpose of the Study:

• To compare the flow dynamics and platelet activation potential between recessed and open pivot hinge designs in bi-leaflet mechanical heart valves.
• To investigate the significance of late-stage valve closure on platelet activation.
• To simulate and analyze fluid flow and particle behavior within different hinge geometries.

Main Methods:

• Solving two-dimensional Navier-Stokes equations using an Eulerian Levelset based sharp interface Cartesian grid method.
• Employing a fixed Cartesian mesh with local mesh refinement for accuracy and efficiency.
• Modeling platelets as point particles using a Lagrangian particle tracking algorithm with one-way coupling for dilute particle flow.

Main Results:

• The open pivot hinge design exhibited lower shear stresses in the hinge region compared to the recessed hinge design.
• The simulation indicated a reduced potential for platelet activation in the open pivot hinge region.
• Late-stage closure dynamics were identified as critical for platelet activation.

Conclusions:

• The open pivot hinge design is potentially safer regarding platelet activation compared to the recessed hinge design.
• Computational fluid dynamics simulations provide valuable insights into the biomechanics of mechanical heart valves.
• Further research into hinge design optimization can lead to improved thrombotic profiles for mechanical heart valves.