Esophageal valve device for placing in the cardia
A luminal valve for placing in a body lumen comprises at least four valve leaflets. The valve has a normally closed configuration in which the leaflets are engaged and an open configuration in which the leaflets are open. The valve may be mounted to an esophageal support.
1. A medical device for placement in a gastrointestinal tract, the medical device comprising:
a valve member comprising a biomimetic viscoelastic polymeric foam material, the valve member having a proximal outer support region with a rim;
at least four valve leaflets;
a main body region extending between the rim and the valve leaflets, the main body region having a generally concave outer face and a generally convex inner face, the valve member having a normally closed configuration in which the leaflets are engaged at a region of co-aption of the valve leaflets and an antegrade open configuration;
the valve having a retrograde open configuration in response to a retrograde force, the valve leaflets and at least a portion of the main body region of the valve configured to invert to allow flow in the retrograde direction and, on reduction in retrograde forces, the main body region and the valve leaflets configured to automatically revert to the normally closed configuration under an inherent biasing of the viscoelastic polymeric foam material;
the main body region of the valve member having a first thickness, the valve leaflets at the region of co-aption having a second thickness which is greater than the first thickness to define a reinforced region which extends in a longitudinal direction; and
a support member which is configured to engage with a wall of the gastrointestinal tract, the rim of the valve being mounted to the support member.
2. The medical device as claimed in claim 1 wherein the valve is an esophageal valve.
3. The medical device as claimed in claim 1 wherein the valve has the antegrade open configuration in which the valve leaflets are opened in response to an antegrade force to allow flow through the valve, wherein the retrograde force is larger than the antegrade force.
4. The medical device as claimed in claim 1 wherein the rim of the valve body is reinforced.
5. The medical device as claimed in claim 1 wherein a pressure of 0.7 mm Hg in an antegrade direction is sufficient to allow a flowrate through the valve of 140ml/min.
6. The medical device as claimed in claim 1 wherein the retrograde force required to open the valve is a pressure of greater than 15 mm Hg and less than 40 mm Hg.
7. The medical device as claimed in claim 1 wherein the viscoelastic foam is stable to gastric fluid for at least 3 months, for at least 4 months, for at least 5 months, for at least 6 months, for at least 7 months, for at least 8 months, for at least 9 months, for at least 10 months, for at least 11 months, or for at least one year.
8. The medical device as claimed in claim 1 wherein the viscoelastic foam takes up less than 5%, less than 10%, less than 15%, less than 20%, less than 25%, or less than 30% by weight of water at equilibrium.
9. The medical device as claimed in claim 1 wherein the viscoelastic foam has a % elongation of from 50% to 3000%, or 200 % to 1200%.
10. The medical device as claimed in claim 1 wherein the viscoelastic foam has a tensile strength of from 0.01 to 5 MPa, or 0.1 to 1.0 MPa, or 0.25 to 0.5 MPa.
11. The medical device as claimed in claim 1 wherein the viscoelastic foam has a Young's Modulus of 0.1 to 0.6 MPa, or 0.1 to 0.5 MPa.
12. The medical device as claimed in claim 1 wherein the viscoelastic foam has a density of from 0.1 g/cm 3 , or 0.3 to 1.2 g/cm 3 , or 0.8 to 0.9 g/cm 3 , or 0.5 to 0.6 g/cm 3 .
13. The medical device as claimed in claim 1 wherein the region of co-aption of the valve leaflets has an axial extent of from 1 mm to 5 mm.
14. The medical device as claimed in claim 1 wherein the second thickness is from 0.1 mm to 10 mm.