Modifying a tilting disk mechanical heart valve design to improve closing dynamics

Area of Science:

• Biomedical Engineering
• Cardiovascular Devices
• Fluid Dynamics

Background:

• Mechanical heart valve closure is influenced by design, materials, and operating conditions.
• Tilting disk valves are common but can cause blood damage due to cavitation during closure.
• Reducing cavitation is crucial for improving the hemocompatibility of mechanical heart valves.

Purpose of the Study:

• To introduce an innovative design for tilting disk mechanical heart valves.
• To improve valve closure dynamics by reducing cavitation and impact forces.
• To evaluate the effectiveness of a "dynamic liquid core" occluder in a simulated mitral position.

Main Methods:

• A standard Delrin occluder was modified to include a "dynamic liquid core".
• The modified and standard occluders were tested in a mitral valve simulation chamber.
• Cavitation energy was measured using high-frequency pressure transients under physiologic (2500 mm Hg/s) and elevated (4500 mm Hg/s) closing conditions.

Main Results:

• The modified valve with a dynamic liquid core demonstrated a significant reduction in cavitation intensity.
• Cavitation intensity was reduced by over 66% at the higher closing load compared to the standard valve.
• The modified valve exhibited a slower, more dampened closure, indicating reduced impact and rebound.

Conclusions:

• Modifying mechanical heart valve structures, like adding a dynamic liquid core, can minimize closure-induced cavitation.
• This approach shows potential for reducing blood damage (hemolysis) associated with mechanical heart valves.
• The modified valve design offers improved closure dynamics and reduced impact forces, suggesting enhanced hemocompatibility.