Thrombus Management And Structural Compliance Features For Prosthetic Heart Valves

Abstract

A prosthetic heart valve can include an outer support assembly, an inner valve assembly, which define between them an annular space, and a pocket closure that bounds the annular space to form a pocket in which thrombus can be formed and retained. Alternatively, or additionally, the outer support assembly and the inner valve assembly can be coupled at the ventricle ends of the outer support assembly and the inner valve assembly, with the outer support assembly being relatively more compliant in hoop compression in a central, annulus portion than at the ventricle end, so that the prosthetic valve can seat securely in the annulus while imposing minimal loads on the inner valve assembly that could degrade the performance of the valve leaflets.

What is claimed is: 
     
         1 . A prosthetic heart valve comprising:
 an outer frame assembly having an atrium portion, a ventricle portion, and an annulus portion between the atrium portion and the ventricle portion, the outer frame assembly including shape memory material such that the outer frame assembly reverts to a memory shape in the absence of applied forces; and   an inner valve assembly including an inner frame and prosthetic valve leaflets attached to the inner frame, the prosthetic valve leaflets configured to allow blood to flow in a downstream direction, the inner frame having an atrium end and a ventricle end, the inner valve assembly coupled to the outer frame assembly by a connection between the ventricle end of the inner frame and the ventricle portion of the outer frame assembly, the inner valve assembly and the outer frame assembly diverging from each other in an upstream direction away from the connection, the annulus portion of the outer frame assembly being spaced radially from the inner valve assembly and radially inwardly deflectable towards the inner valve assembly to accommodate positioning of the annulus portion within a natural valve annulus having a perimeter smaller than a minimum perimeter of the annulus portion when the outer frame assembly has the memory shape,   wherein the annulus portion of the outer frame assembly is configured to be implanted within the natural valve annulus and to have a shape in which a middle of the annulus portion has a smaller diameter than (i) a first portion of the annulus portion near the ventricle portion and (ii) a second portion of the annulus portion near the atrium portion.   
     
     
         2 . The prosthetic heart valve of  claim 1 , wherein each of the atrium portion and the annulus portion of the outer frame assembly is D-shaped in cross-section. 
     
     
         3 . The prosthetic heart valve of  claim 1 , wherein the inner valve assembly includes a covering disposed about a periphery of the inner frame and formed of a material substantially impermeable to blood. 
     
     
         4 . The prosthetic heart valve of  claim 1 , wherein the outer frame assembly includes: an outer frame; and an inner covering disposed about an inner periphery of the outer frame and formed of a material substantially impermeable to blood. 
     
     
         5 . The prosthetic heart valve of  claim 1 , wherein: the inner valve assembly includes a covering disposed about a periphery of the inner frame and formed of a material substantially impermeable to blood, and the outer frame assembly includes an outer frame and an inner covering disposed about an inner periphery of the outer frame and formed of a material substantially impermeable to blood, the covering of the inner frame coupled to the inner covering of the outer frame. 
     
     
         6 . The prosthetic heart valve of  claim 1 , wherein the shape is an hourglass shape. 
     
     
         7 . The prosthetic heart valve of  claim 1 , wherein the annulus portion of the outer frame assembly has a perimeter that is sized to fit into an annulus of an atrioventricular valve, each of the atrium portion and the annulus portion of the outer frame assembly being D-shaped in cross-section. 
     
     
         8 . The prosthetic heart valve of  claim 1 , wherein: when the prosthetic heart valve is implanted within the natural valve annulus, the ventricle portion of the outer frame assembly has a maximum perimeter larger than a maximum perimeter of the annulus portion, and the ventricle portion of the outer frame assembly has a minimum perimeter smaller than the minimum perimeter of the annulus portion. 
     
     
         9 . The prosthetic heart valve of  claim 1 , wherein the outer frame assembly has a stiffness in resistance to radial compression that varies in an axial direction of the outer frame assembly. 
     
     
         10 . The prosthetic heart valve of  claim 1 , wherein the inner valve assembly is substantially cylindrical. 
     
     
         11 . The prosthetic heart valve of  claim 10 , wherein the outer frame assembly has a taper in which the atrium portion has a larger diameter than the ventricle portion. 
     
     
         12 . The prosthetic heart valve of  claim 1 , wherein the inner valve assembly and the outer frame assembly define therebetween an annular region. 
     
     
         13 . The prosthetic heart valve of  claim 12 , further comprising a pocket closure coupled between the outer frame assembly and the inner valve assembly and enclosing therewith a portion of the annular region. 
     
     
         14 . The prosthetic heart valve of  claim 13 , wherein the pocket closure forms a thrombus retaining pocket, at least a portion of the pocket closure formed of a material having a porosity that is sufficiently large to allow red blood cells to pass through the pocket closure into the thrombus retaining pocket and that is sufficiently small to prevent thrombus formed from the red blood cells to pass through the pocket closure from the thrombus retaining pocket. 
     
     
         15 . The prosthetic heart valve of  claim 14 , wherein the pocket closure is formed at least in part of a material having a pore size less than about 160 μm. 
     
     
         16 . The prosthetic heart valve of  claim 15 , wherein the pocket closure is formed at least in part of a material having a pore size between about 90 μm and about 120 μm. 
     
     
         17 . The prosthetic heart valve of  claim 14 , wherein the pocket closure is formed at least in part of a material that is one of a woven material or a knit material.