A numerical simulation of mechanical heart valve closure fluid dynamics

Area of Science:

• Biomedical Engineering
• Fluid Dynamics
• Medical Devices

Background:

• Bileaflet mechanical heart valves (BMHVs) are crucial for cardiovascular health.
• Understanding the fluid dynamics during valve closure is essential for optimizing BMHV design and performance.
• Previous studies have explored various aspects of valve dynamics, but detailed analysis of leaflet tip geometry effects during closure remains an area for investigation.

Purpose of the Study:

• To develop and validate a computational fluid dynamics (CFD) model for simulating the closure phase of BMHVs.
• To investigate the impact of leaflet tip geometry and housing gap width on closure fluid dynamics.
• To evaluate how leaflet motion and velocity influence pressure dynamics during valve closure.

Main Methods:

• A CFD model was developed to simulate bileaflet mechanical heart valve closure.
• The model was applied to six distinct combinations of leaflet tip geometry and housing gap width.
• Leaflet motion, velocity, and pressure distributions were analyzed during the closing phase.

Main Results:

• A significant negative pressure develops on the atrial side of the leaflet tip as closure progresses.
• The lowest pressure is observed just before the leaflet reaches its fully closed position.
• A threefold decrease in leaflet tip velocity during the final four degrees of motion resulted in a 50% reduction in peak negative pressure magnitude.

Conclusions:

• The CFD model effectively simulates BMHV closure dynamics and the influence of leaflet tip geometry.
• Leaflet tip velocity during the closing phase is a critical factor in determining closure-induced negative pressures.
• Optimizing leaflet tip design and controlling closure velocity can mitigate adverse pressure effects, potentially reducing risks associated with BMHV implantation.