Elastomeric leaflet for prosthetic heart valves

Abstract

A leaflet for a prosthetic valve formed of at least one layer that includes a composite material containing at least one expanded fluoropolymer membrane having serpentine fibrils and an elastomer is provided. The fluoropolymer may be polytetrafluoroethylene. In at least one embodiment, the elastic properties are present in an axial direction the leaflet. The leaflets may be single layered or multi-layered. The leaflets may be coupled to a support structure and movable between open and closed configurations relative to the support structure to form a heart valve. The elasticity within the leaflets permits, among other things, the leaflets to bend with a reduced occurrence of wrinkles as the valve opens and closes. The elastic properties of the leaflet also, among other things, improve bending properties and reduce closure stresses, thereby extending the life of the leaflet.

What is claimed is: 
     
         1 . A prosthetic valve, comprising:
 a leaflet able to be cycled between a closed configuration to substantially prevent blood flow through the prosthetic valve and an open configuration to allow blood flow through the prosthetic valve, the leaflet including at least one layer comprising a composite material including at least one expanded fluoropolymer membrane having serpentine fibrils and an elastomer,   wherein the at least one expanded fluoropolymer membrane is a retracted fluoropolymer membrane,   wherein the expanded fluoropolymer membrane comprises a plurality of pores and the elastomer is present in the pores, and   wherein the composite material may be elongated from a retracted state to an elongated state, and the composite material is substantially free of wrinkles when in the retracted state.   
     
     
         2 . The prosthetic valve of  claim 1 , wherein the composite material that exhibits an increase in stiffness when elongated to at least about 30% strain. 
     
     
         3 . The prosthetic valve of  claim 1 , wherein the composite material exhibits an unrecoverable strain energy density value of less than about 90%. 
     
     
         4 . The prosthetic valve of  claim 1 , wherein the fluoropolymer is polytetrafluoroethylene. 
     
     
         5 . The prosthetic valve of  claim 1 , wherein the expanded fluoropolymer membrane comprises a microstructure of substantially only serpentine fibrils. 
     
     
         6 . The prosthetic valve of  claim 1 , wherein the leaflet is operatively coupled to a support structure and is movable between the closed and open configurations relative to the support structure. 
     
     
         7 . The prosthetic valve of  claim 1 , wherein the leaflet has a ratio of thickness (μm) to number of layers of the composite material of less than about 5. 
     
     
         8 . The prosthetic valve of  claim 1 , wherein the leaflet exhibits elastic properties in an axial direction of the leaflet. 
     
     
         9 . The prosthetic valve of  claim 1 , wherein the elastomer is selected from the group consisting of perfluoromethylvinyl ether-tetrafluoroethylene copolymers, perfluoro (alkyl vinyl ether)-tetrafluoroethylene copolymers, silicones and polyurethanes. 
     
     
         10 . The prosthetic valve of  claim 1 , wherein the elastomer is present in substantially all of the pores of the fluoropolymer material. 
     
     
         11 . A valve leaflet material comprising a composite material including a retracted membrane having serpentine fibrils and an elastomer, the membrane including a plurality of pores and the elastomer is present in the plurality of pores, and wherein the composite material may be elongated from a retracted state to an elongated state, and the composite material is substantially free of wrinkles when in the retracted state and exhibits an increase in stiffness when elongated to at least about 30% strain. 
     
     
         12 . The valve leaflet material of  claim 1 , wherein the composite material exhibits an unrecoverable strain energy density value of less than about 90%. 
     
     
         13 . The valve leaflet material of  claim 1 , wherein the membrane is polytetrafluoroethylene. 
     
     
         14 . The valve leaflet material of  claim 1 , wherein the membrane comprises a microstructure of substantially only serpentine fibrils. 
     
     
         15 . The valve leaflet material of  claim 1  formed into a leaflet that is operatively coupled to a support structure and is movable between the closed and open configurations relative to the support structure. 
     
     
         17 . The valve leaflet material of  claim 15 , wherein the leaflet has a ratio of thickness (μm) to number of layers of the composite material of less than about 5. 
     
     
         18 . The valve leaflet material of  claim 15 , wherein the leaflet exhibits elastic properties in an axial direction of the leaflet. 
     
     
         19 . The valve leaflet material of  claim 1 , wherein the elastomer is selected from the group consisting of perfluoromethylvinyl ether-tetrafluoroethylene copolymers, perfluoro (alkyl vinyl ether)-tetrafluoroethylene copolymers, silicones and polyurethanes. 
     
     
         20 . The valve leaflet material of  claim 1 , wherein the elastomer is present in substantially all of the pores of the fluoropolymer material.