Heart valve stents adapted for post-implant expansion
A prosthetic heart valve configured to replace a native heart valve and having a support frame configured to be reshaped into an expanded form in order to receive and/or support an expandable prosthetic heart valve therein is disclosed, together with methods of using same. The prosthetic heart valve may be configured to have a generally rigid and/or expansion-resistant configuration when initially implanted to replace a native valve (or other prosthetic heart valve), but to assume a generally expanded form when subjected to an outward force such as that provided by a dilation balloon or other mechanical expander.
1. A prosthetic heart valve adapted for post-implant expansion and having an inflow end and an outflow end, comprising:
an inner structural support stent including a generally circular inflow band oriented around a central axis and having three upstanding commissure posts extending in an outflow direction, the stent defining an implant circumference that is substantially non-compressible in normal physiological use and has a first diameter, and wherein the inflow band is a continuous solid band except for at least one point of discontinuity around a periphery of the inflow band formed by a point of reduced axial cross sectional area so that upon application of an outward dilatory force from within the support stent substantially larger than forces associated with normal physiological use the inflow band fails by being broken or stretched at the at least one point of discontinuity and permits expansion of the support stent from the first diameter to a second diameter larger than the first diameter but prevents contraction of the inflow band; and
a plurality of flexible leaflets supported by the stent and configured to ensure one-way blood flow therethrough.
2. The prosthetic heart valve of claim 1 , wherein the at least one point of discontinuity is formed by one of at least one notch located below one of the commissure posts.
3. The prosthetic heart valve of claim 2 , wherein the one notch is located at an inflow edge of the one commissure post.
4. The prosthetic heart valve of claim 2 , wherein there is a single notch around the periphery of the inflow band located below one of the commissure posts.
5. The prosthetic heart valve of claim 2 , wherein there is a notch located below each of the commissure posts.
6. The prosthetic heart valve of claim 1 , wherein the at least one point of discontinuity is formed by a single notch located around the periphery of the inflow band.
7. The prosthetic heart valve of claim 1 , wherein the at least one point of discontinuity is formed by a plurality of notches located around the periphery of the inflow band.
8. The prosthetic heart valve of claim 1 , wherein the at least one point of discontinuity is formed by at least one set of aligned notches in outflow and inflow edges of the inflow band around the periphery thereof.
9. The prosthetic heart valve of claim 1 , wherein the at least one point of discontinuity is configured to break upon application of an outward dilatory force from within the support stent of at least 1 atmosphere.
10. The prosthetic heart valve of claim 1 , wherein the at least one point of discontinuity is configured to break upon application of an outward dilatory force from within the support stent of up to 12 atmospheres.
11. The prosthetic heart valve of claim 1 , wherein each commissure post has a gap between two sides and the inflow band extends across the gaps in two wall segments, wherein the at least one point of discontinuity is located where the two wall segments come together.
12. The prosthetic heart valve of claim 1 , further including a unique identifier on the support stent visible from outside the body after implant of the prosthetic heart valve that identifies the support stent as being expandable.
13. The prosthetic heart valve of claim 12 , wherein the unique identifier is a numerical valve size in odd 2-millimeter increments between 15-33 mm.
14. The prosthetic heart valve of claim 12 , wherein the unique identifier is formed by a cutout in the inflow band.
15. The prosthetic heart valve of claim 1 , wherein the inner structural support stent is made of a single piece of titanium.
16. The prosthetic heart valve of claim 15 , wherein each commissure post has a gap between two sides and the inflow band extends across the gaps in two wall segments, wherein the at least one point of discontinuity is located where the two wall segments come together between the two sides of at least one of the commissure posts.
17. The prosthetic heart valve of claim 1 , wherein the inner structural support stent is made of a single piece of acetal copolymer.
18. The prosthetic heart valve of claim 17 , wherein the inner structural support stent further includes cusp supports located between each of the commissure posts, each cusp support extending away from the inflow band and diverging toward but not touching the adjacent commissure posts.
19. The prosthetic heart valve of claim 17 , wherein each commissure post has a gap between two sides and the inflow band extends across the gaps in two wall segments, wherein the at least one point of discontinuity is located where the two wall segments come together between the two sides of at least one of the commissure posts.
20. The prosthetic heart valve of claim 19 , wherein there is one of the at least one point of discontinuity located at each of the commissure posts.