Replacement heart valves, delivery devices and methods
A replacement heart valve and method of treating valve insufficiency includes an expandable frame configured to engage a native valve annulus. A valve body is coupled to the frame. The valve body can include a leaflet portion and possibly a skirt portion. A portion of the frame has a foreshortening portion configured to longitudinally expand when urged to a radially compacted state and longitudinally contract when urged to a radially expanded state. In one embodiment the valve skirt is attached to the frame so that it can adapt to changes in the length of the frame. A delivery device in some embodiments can use one or more coverings, such as sheaths, to controllably release the replacement heart valve at a native heart valve.
1. A multi-stage delivery system for controlled deployment of a replacement heart valve by limiting the amount of expansion during the various stages, the multi-stage delivery system comprising:
an elongate inner member comprising a proximal end and a distal end;
an inner retention ring on the elongate inner member, the inner retention ring being configured to engage a radially compacted proximal end of a replacement heart valve;
a support tube configured to be slidable over the elongate inner member and the inner retention ring and configured to cover at least the radially compacted proximal end of the replacement heart valve when the proximal end of the replacement heart valve is engaged with the inner retention ring;
an outer sheath configured to be slidable over the support tube and configured to cover a distal end of the replacement heart valve to retain the replacement heart valve in a radially compacted configuration when the proximal end of the replacement heart valve is covered by the support tube and engaged with the inner retention ring; and
a secondary sheath configured to be slidable over the support tube and configured to cover at least a portion of the replacement heart valve, wherein the secondary sheath is sized to slide within the outer sheath;
wherein the delivery system is configured such that when the proximal end of the replacement heart valve is both engaged with the inner retention ring and covered by the support tube, and when the distal end of the replacement heart valve is covered by the outer sheath:
proximal retraction of the outer sheath relative to the elongate inner member exposes the distal end of the replacement heart valve and allows the distal end of the replacement heart valve to at least partially radially expand while the proximal end of the replacement heart valve remains covered by the support tube; and
proximal retraction of the support tube relative to the elongate inner member exposes the proximal end of the replacement heart valve and allows the proximal end of the replacement heart valve to at least partially radially expand.
2. The delivery system of claim 1 , wherein the elongate inner member comprises a tube having a lumen sized and configured to slidably accommodate a guidewire.
3. The delivery system of claim 1 , further comprising a nose cone connected to the distal end of the elongate inner member.
4. The delivery system of claim 1 , wherein the inner retention ring comprises a plurality of teeth configured to engage tabs on the proximal end of the replacement heart valve.
5. The delivery system of claim 1 , wherein the support tube is a ring.
6. The delivery system of claim 1 , further comprising a retainer member configured to retain the outer sheath in place relative to the elongate inner member.
7. The delivery system of claim 1 , wherein the secondary sheath is connected to the outer sheath with one or more tension members such that retraction of the outer sheath from covering the replacement heart valve also causes the secondary sheath to withdraw from covering the replacement heart valve.
8. The delivery system of claim 1 , further comprising a replacement heart valve having a proximal end and a distal end.
9. The delivery system of claim 8 , wherein the proximal end of the replacement heart valve is engaged with the inner retention ring on the elongate inner member and is covered by the support tube; and the distal end of the replacement heart valve is covered by the outer sheath.
10. The delivery system of claim 8 , wherein the replacement heart valve comprises a plurality of distal anchors having tips that extend proximally.