Surgical heart valves 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 surgical prosthetic heart valve adapted for post-implant expansion and having an inflow end and an outflow end, comprising:
an undulating flexible wireform surrounding a flow axis and defining three alternating arcuate cusps and three upstanding commissures extending toward the outflow end of the heart valve, the wireform being covered with a biocompatible fabric;
a plurality of flexible leaflets attached to the fabric covering the wireform and configured to close toward the flow axis and ensure one-way blood flow through the heart valve; and
a support stent surrounding the flow axis and having three alternating cusp regions and three upstanding commissure posts aligned with and located radially outward of the wireform commissures, the support stent defining an implant circumference that is substantially non-compressible from a first diameter prior to implant and in normal physiological use, and the support stent including a band having at least one point of weakness configured to stretch and permit expansion of the support stent from the first diameter to a second diameter larger than the first diameter upon application of an outward dilatory force from within the support stent substantially larger than forces associated with normal physiological use, the support stent being covered with a biocompatible fabric and attached to the fabric covering the wireform in a manner that decouples from the leaflets the forces associated with expansion of the support stent from the first diameter to a second diameter to avoid significantly stretching the leaflets.
2. The prosthetic heart valve of claim 1 , wherein the support stent is a single polymer band.
3. The prosthetic heart valve of claim 1 , wherein the support stent is a single metallic band.
4. The prosthetic heart valves of claim 1 , wherein the prosthetic heart valve is a two-part valve with the plurality of flexible leaflets and wireform forming a detachable frame that couples to the support stent at the commissure posts thereof.
5. The prosthetic heart valve of claim 1 , further including a unique identifier on the support stent visible from outside the body after implant that identifies the support stent as being expandable.
6. A surgical prosthetic heart valve adapted for post-implant expansion and having an inflow end and an outflow end, comprising:
a support stent surrounding the flow axis and having three alternating cusp regions and three upstanding commissure posts, the support stent defining an implant circumference that is substantially non-compressible from a first diameter prior to implant and in normal physiological use, and the support stent including a band having three points of weakness located equidistantly around the implant circumference configured to stretch and permit expansion of the support stent from the first diameter to a second diameter larger than the first diameter upon application of an outward dilatory force from within the support stent substantially larger than forces associated with normal physiological use, wherein the support stent is formed by a framework of a lower circular band structurally connected to an upper undulating band via a plurality of axial struts, including a pair of axial struts below each commissure post, and wherein there are points of weakness in the lower circular band in between and on the outside of each pair of axial struts; and
a plurality of flexible leaflets attached to the support stent and configured to close toward the flow axis and ensure one-way blood flow through the heart valve.
7. The prosthetic heart valve of claim 6 , wherein the support stent is a single polymer band.
8. The prosthetic heart valve of claim 6 , wherein the support stent is a single metallic band.
9. The prosthetic heart valve of claim 6 , further including a unique identifier on the support stent visible from outside the body after implant that identifies the support stent as being expandable.
10. The prosthetic heart valve of claim 6 , wherein the support stent is a titanium alloy covered with fabric, and the flexible leaflets are secured to the fabric around the support stent.
11. The prosthetic heart valve of claim 6 , wherein the three points of weakness each comprise a series of diamond-shaped struts that straighten out when stretched.