Prosthetic valve and delivery tool therefor
Embodiments of the present disclosure include apparatus for use at a native valve of a heart of a subject. A delivery tool has a shaft, a capsule disposed at a distal portion of the tool, and a balloon that is disposed within the capsule and coupled to the shaft. A tubular frame of a prosthetic valve is compressed around the balloon, such that shape-memory flanges of the prosthetic valve, and a shape-memory upstream support portion of the prosthetic valve, are each constrained within a respective capsule-portion of the capsule. The capsule is openable by moving the capsule-portions apart, such that the flanges and the upstream support portion automatically deflect radially outward, while the tubular frame remains compressed around the balloon, and inflation of the balloon plastically expands the tubular frame radially. Other embodiments are also described.
1. Apparatus for use at a native valve of a heart of a subject, the apparatus comprising:
a delivery tool, comprising:
a shaft, having a shaft-axis;
a capsule, disposed at a distal portion of the tool, and comprising an upstream capsule-portion and a downstream capsule-portion, the capsule being openable by moving the upstream capsule-portion and the downstream capsule-portion apart; and
a balloon, coupled to the shaft, and disposed within the capsule; and
a prosthetic valve, comprising:
a tubular frame that circumscribes a longitudinal axis to define a lumen along the longitudinal axis, that is compressed around the balloon, and that is disposed within the capsule; and
an outer frame, the outer frame comprising:
one or more shape-memory flanges, constrained within the downstream capsule-portion; and
a shape-memory upstream support portion, constrained within the upstream capsule-portion,
wherein:
the flanges are configured to automatically deflect radially outward from the tubular frame upon exposure from the downstream capsule-portion,
the upstream support portion is configured to automatically deflect radially outward upon exposure from the upstream capsule-portion,
the tubular frame is configured to remain compressed around the balloon upon exposure of the tubular frame from the capsule,
the outer frame is disposed radially outward from the tubular frame and longitudinally overlapping the tubular frame, and
while the tubular frame is exposed from the capsule:
the tubular frame is configured to inhibit the outer frame from radially expanding, prior to inflation of the balloon, and
inflation of the balloon plastically expands the tubular frame radially.
2. The apparatus according to claim 1 , wherein the prosthetic valve further comprises one or more prosthetic valve leaflets disposed within the lumen and coupled to the tubular frame.
3. The apparatus according to claim 1 , wherein the tubular frame is disposed within the downstream capsule-portion of the capsule.
4. The apparatus according to claim 1 , wherein the tubular frame is composed of a material that is not a shape-memory alloy.
5. The apparatus according to claim 4 , wherein the tubular frame is composed of steel.
6. The apparatus according to claim 4 , wherein the tubular frame is composed of cobalt chrome.
7. The apparatus according to claim 1 , wherein the flanges are composed of a shape-memory alloy.
8. The apparatus according to claim 7 , wherein the flanges are composed of nickel titanium.
9. The apparatus according to claim 1 , wherein the balloon is fixed to the shaft.
10. The apparatus according to claim 9 , wherein both the upstream capsule-portion and the downstream capsule-portion are axially movable with respect to the shaft.
11. The apparatus according to claim 10 , wherein:
a first capsule-portion selected from the group consisting of: the upstream capsule-portion and the downstream capsule-portion is attached to a tube, and is axially movable with respect to the shaft by the tube being slid over the shaft, and
a second capsule-portion selected from the group is attached to a rod, and is axially movable with respect to the shaft by the rod being slid though the shaft.
12. The apparatus according to claim 9 , wherein the upstream capsule-portion is retractable from over the upstream support portion by being moved away from the balloon, and the downstream capsule-portion is retractable from over the flanges by being moved away from the balloon.
13. The apparatus according to claim 1 , wherein the delivery tool further comprises one or more elongate projections disposed within the downstream capsule-portion, each of the projections having (i) a tip-portion, and (ii) a base-portion, disposed deeper than the tip-portion into the downstream capsule-portion, the projections arranged circumferentially around the shaft-axis such that the tip-portions are arranged circumferentially around a downstream balloon-portion of the balloon, with the tip-portion of each projection being closer than its corresponding base-portion to the tubular frame.
14. The apparatus according to claim 13 , wherein each of the projections is sufficiently stiff that, when pushed against the tubular frame, it is capable of applying, to the tubular frame, an axial pushing force of at least 0.5 N.
15. The apparatus according to claim 13 , wherein each of the projections is sufficiently stiff that, when pushed against the tubular frame, the one or more projections are capable collectively of applying, to the tubular frame, an axial pushing force of at least 3 N.
16. The apparatus according to claim 13 , wherein the tubular frame is disposed within the downstream capsule-portion of the capsule, and wherein the downstream capsule-portion is retractable from over the tubular frame and at least the tip-portions, exposing, from the downstream capsule-portion, the tubular frame and at least the tip-portions.
17. The apparatus according to claim 16 , wherein, while the tubular frame and the tip-portions are exposed from the downstream capsule-portion, inflation of the balloon (i) radially expands the tubular frame, and (ii) deflects each of the projections radially outward within a respective radial plane on which the shaft-axis and the projection lie.
18. The apparatus according to claim 17 , wherein, while the tubular frame and the tip-portions are exposed from the downstream capsule-portion, inflation of the balloon uniformly fills the lumen of the tubular frame.
19. The apparatus according to claim 17 , wherein a widest part of the balloon is disposed within the lumen.
20. The apparatus according to claim 17 , wherein each projection has a radial stiffness in its radial plane, and has a lateral stiffness in a respective lateral plane, the lateral stiffness being greater than the radial stiffness.
21. The apparatus according to claim 16 , wherein:
the balloon has an upstream balloon-portion, a downstream balloon-portion, and a body balloon-portion therebetween,
the tubular frame is compressed around the body balloon-portion, and
while the tubular frame and the tip-portions are exposed from the downstream capsule-portion, inflation of the balloon (i) radially expands the tubular frame by pressing the body balloon-portion radially outward against the tubular frame, and (ii) deflects the projections radially outward by pressing the downstream balloon-portion radially outward against the projections.
22. The apparatus according to claim 21 , wherein the downstream balloon-portion of the balloon extends away from the tubular frame, and is tapered.
23. The apparatus according to claim 21 , wherein the upstream balloon-portion of the balloon extends away from the tubular frame, and is tapered.
24. The apparatus according to claim 21 , wherein the tip-portion of each of the projections abuts the tubular frame, and the apparatus is configured such that the tip-portion of each of the projections remains in contact with the tubular frame as the balloon is inflated.
25. The apparatus according to claim 21 , wherein a downstream end of the tubular frame defines a frame-circumference, the tip-portions define a projection-circumference, and while the tubular frame and the tip-portions are exposed from the downstream capsule-portion, inflation of the balloon increases the projection-circumference at the same rate as the balloon increases the frame-circumference.
26. The apparatus according to claim 13 , wherein the tip-portion of each of the projections abuts the tubular frame.
27. The apparatus according to claim 26 , wherein the projections are not attached to the tubular frame.
28. The apparatus according to claim 1 , wherein the flanges are configured such that, upon exposure of the tubular frame from the downstream capsule-portion, the flanges automatically deflect:
radially outward from the tubular frame, and
toward the upstream support portion.