Function of expanded-polytetrafluoroethylene laminated trileaflet valves in animals

Area of Science:

• Biomaterials Science
• Cardiovascular Engineering
• Surgical Innovation

Background:

• Developing durable stent-mounted cardiac valve prostheses is crucial for treating valvular heart disease.
• Expanded polytetrafluoroethylene (ePTFE) offers potential for leaflet fabrication due to its material properties.

Purpose of the Study:

• To assess the long-term in vivo performance of stent-mounted trileaflet cardiac valve prostheses fabricated with ePTFE leaflets of varying thicknesses.
• To identify factors influencing valve dysfunction in a canine model.

Main Methods:

• Fabrication of trileaflet valve prostheses using laminated ePTFE films (0.003-mm thickness, 4-15 layers).
• Implantation of 28 valves in the tricuspid position in dogs.
• Cardiac catheterization for functional assessment and autopsy for failure analysis in surviving animals (n=20) up to 15 months post-implantation.

Main Results:

• 12 out of 20 surviving dogs maintained good valve function for up to 15 months.
• 8 dogs developed valve dysfunction within 6 months.
• Causes of dysfunction included cusp stiffening/retraction (6 dogs), suture ring dehiscence (1 dog), and strut entrapment (1 dog).

Conclusions:

• Leaflet material thickness is a critical determinant of long-term in vivo performance for ePTFE cardiac valve prostheses.
• Further optimization of leaflet design and material properties is necessary to improve prosthesis durability and reduce failure rates.