US Patent 8029557 Esophageal valve

An esophageal valve comprising a polymeric valve body having an outer support region, at least three valve leaflets, and a main body region extending between the support region and the valve leaflets. The valve has a normally closed configuration in which the valve is closed, an antegrade open configuration in which the valve leaflets are opened in response to an antegrade force to allow flow through the valve and a retrograde open configuration in response to a retrograde force which is substantially larger than the antegrade force.