Creep and flexibility measurements on plastic frames for tissue heart valves

Area of Science:

• Biomaterials Science
• Medical Device Engineering
• Polymer Science

Background:

• Heart valve replacement often utilizes flexible frames.
• Material creep can compromise device longevity and function.
• Understanding creep in plastic components is crucial for long-term performance.

Purpose of the Study:

• To investigate the influence of design on the creep potential of plastic flexible frames for heart valves.
• To assess the long-term stability and creep behavior of polypropylene frames after clinical use.
• To evaluate the feasibility of achieving 30 years of creep-free performance.

Main Methods:

• In vitro accelerated fatigue testing of plastic heart valve frames.
• Analysis of explanted frames after over 10 years of clinical implantation.
• Mechanical testing to evaluate material flexibility and creep.

Main Results:

• Heart valve frame design significantly influences the creep potential of the plastic material.
• Polypropylene flexibility remained unaffected by accelerated fatigue testing, shelf storage, or clinical implantation.
• No significant creep was observed in frames after more than a decade of in vivo use.

Conclusions:

• The design of flexible plastic heart valve frames is a critical factor in managing creep.
• Polypropylene demonstrates excellent long-term stability and resistance to creep in cardiac applications.
• A 30-year creep-free lifespan for flexible plastic frames in tissue heart valves is a viable possibility.