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Preliminary study on the new self-closing mechanical mitral valve.
1Department of Precision Machinery Engineering, The University of Tokyo,Japan. naemura@itao.pe.u-tokyo.ac.jp
Artificial Organs
|September 22, 1999
Summary
This study introduces a novel self-closing mechanical mitral valve designed to mimic natural valve function by closing before systole. Initial tests show promising results for improved valve timing without affecting inflow volume.
Area of Science:
- Biomedical Engineering
- Cardiovascular Devices
- Prosthetic Valve Design
Background:
- Natural mitral valves close before systole, unlike conventional mechanical valves that close after.
- Current mechanical mitral valves present a timing mismatch with natural cardiac cycles.
Purpose of the Study:
- To develop a self-closing mechanical mitral valve that initiates closure before systole.
- To establish design parameters for a self-closing mitral valve through experimental evaluation.
Main Methods:
- Modification of a CarboMedics bileaflet valve by adjusting leaflet center of gravity with a lead block.
- Evaluation using a pulse duplicator and high-speed X-ray videography under controlled conditions (60 bpm, 4 L/min).
Main Results:
- The modified valve demonstrated closure initiation before systole.
- No adverse impact on inflow volume was observed.
- Key design parameters were identified: leaflet momentum of inertia < 14.9 x 10^-9 kg.m^2 and gravitational torque > 4.2 x 10^-6 N.m.
Conclusions:
- The self-closing valve design shows potential for improved physiological timing.
- A design strategy for future self-closing mitral valve prototyping was established.
- Consideration of leaflet positioning is crucial for surgical implementation.