Transcatheter Valve To Treat Small Native Mitral Anatomy
20230025890 · 2023-01-26
Assignee
Inventors
Cpc classification
A61F2220/0008
HUMAN NECESSITIES
A61F2/2427
HUMAN NECESSITIES
International classification
Abstract
A prosthetic mitral valve with improved blood flow to the left ventricular outflow tract (LVOT). The prosthetic mitral valve includes an expandable outer stent having an atrial end and a ventricular end, and an expandable inner stent attached to and at least partially positioned within the outer stent. The inner stent has an inflow end, an outflow end and a connector securing a tether. A valve assembly including a cuff and a plurality of leaflets may be disposed within the inner stent. The outer stent is expandable from a delivery condition in which the outer stent is axially elongated to a deployed condition in which a first portion of the outer stent is folded upon a second portion of the outer stent to define a flange for engaging an atrial surface of a native valve annulus and to stabilize the prosthetic heart valve within the native valve annulus.
Claims
1. A prosthetic heart valve, comprising: an expandable inner stent defining an inflow end and an outflow end; a valve assembly disposed within the inner stent, the valve assembly including a cuff and a plurality of leaflets; an outer stent secured to and at least partially surrounding the inner stent, the outer stent defining an atrial end and a ventricular end, and being expandable from a delivery condition in which the outer stent is axially elongated to a deployed condition in which a first portion of the outer stent is folded upon a second portion of the outer stent such that the first and second portions collectively form a flange sized to engage an atrial surface of a native valve annulus; and a tether to secure the prosthetic heart valve within the native valve annulus.
2. The prosthetic heart valve of claim 1, wherein the outer stent further comprises a body portion disposed between the second portion and the ventricular end of the outer stent, the body portion shaped to sit within the native valve annulus when the outer stent is in the deployed condition.
3. The prosthetic heart valve of claim 2, wherein the outer stent defines a first junction between the body portion and the second portion, the second portion being pivotable outwardly about the first junction when the outer stent transitions from the delivery condition to the deployed condition.
4. The prosthetic heart valve of claim 3, wherein the outer stent defines a second junction between the first portion and the second portion, the first portion being bendable underneath the second portion when the outer stent transitions from the delivery condition to the deployed condition.
5. The prosthetic heart valve of claim 3, wherein the outer stent defines a second junction between the first portion and the second portion, the first portion being bendable to lie above the second portion when the outer stent transitions from the delivery condition to the deployed condition.
6. The prosthetic heart valve of claim 3, wherein a distance between the first junction and the ventricular end of the outer stent is between about 5 mm and about 15 mm when the outer stent is in the deployed condition.
7. The prosthetic heart valve of claim 1, further comprising a sealing cuff disposed on a surface of the flange to seal a space between the prosthetic heart valve and the native valve annulus.
8. The prosthetic heart valve of claim 7, wherein the sealing cuff is formed of a stretchable fabric.
9. The prosthetic heart valve of claim 7, wherein the sealing cuff is formed of a plurality of discrete fabric pieces.
10. The prosthetic heart valve of claim 1, further comprising a pivot arm coupled to an anterior side of the outer stent at a pivot point, the pivot arm being pivotable between a collapsed condition in which a free end of the pivot arm extends in a ventricular direction when the outer stent is in the delivery condition and an expanded condition in which a native anterior leaflet is clamped between the pivot arm and the outer stent.
11. The prosthetic heart valve of claim 1, further comprising an apical pad for securing the tether to a ventricular wall of the heart.
12. A prosthetic heart valve, comprising: an expandable inner stent defining an inflow end and an outflow end; a valve assembly disposed within the inner stent, the valve assembly including a cuff and a plurality of leaflets; an outer stent secured to and at least partially surrounding the inner stent, the outer stent defining a first foldable portion, a second foldable portion, a body portion, a first junction between the second foldable portion and the body portion, and a second junction between the first foldable portion and the second foldable portion, the outer stent being expandable from a delivery condition in which the first foldable portion, the second foldable portion and the body portion are substantially aligned to a deployed condition in which the second foldable portion pivots outwardly about the first junction relative to the body portion and the first foldable portion curls about the second junction such that the first foldable portion and the second foldable portion collectively form a double walled flange sized to engage an atrial surface of a native valve annulus; a sealing cuff disposed on a surface of the double walled flange; and a tether to anchor the prosthetic heart valve within the native valve annulus.
13. The prosthetic heart valve of claim 12, wherein the first foldable portion curls underneath the second foldable portion when the outer stent is in the deployed condition and the sealing cuff is disposed on a surface of the first foldable portion.
14. The prosthetic heart valve of claim 12, wherein the first foldable portion curls to overlie the second foldable when the outer stent is in the deployed condition and the sealing cuff is disposed on a surface of the second foldable portion.
15. The prosthetic heart valve of claim 12, further comprising a fabric configured to promote ingrowth disposed on an abluminal surface of the body portion.
16. A method of implanting a prosthetic heart valve, comprising: delivering a delivery device to a target site adjacent to a native valve annulus, the delivery device holding a prosthetic heart valve including an inner stent, a valve assembly disposed within the inner stent, an outer stent secured to and at least partially surrounding the inner stent and a tether; deploying the prosthetic heart valve from the delivery device and allowing a first portion of the outer stent to curl upon a second portion of the outer stent, the first and second portions collectively forming a flange; engaging the flange against an atrial surface of a native valve annulus; tensioning the tether; and securing the tether to the wall of the heart.
17. The method of claim 16, wherein the tensioning step compresses the first and second portions toward one another.
18. The method of claim 16, wherein the delivering step comprises percutaneously delivering the prosthetic heart valve to the native mitral annulus using a transapical approach.
19. The method of claim 16, wherein the delivering step comprises percutaneously delivering the prosthetic heart valve to the native mitral annulus using a transseptal approach.
20. The method of claim 16, further comprising: pivoting a pivot arm coupled to an anterior side of the outer stent; and clamping a native anterior leaflet against an abluminal surface of the outer stent away from a left ventricular outflow tract of a patient.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Various embodiments of the present disclosure are described herein with reference to the drawings, wherein:
[0015]
[0016]
[0017]
[0018]
[0019]
[0020]
[0021]
[0022]
DETAILED DESCRIPTION
[0023] Blood flows through the mitral valve from the left atrium to the left ventricle. As used herein in connection with a prosthetic heart valve, the term “inflow end” refers to the end of the heart valve through which blood enters when the valve is functioning as intended, and the term “outflow end” refers to the end of the heart valve through which blood exits when the valve is functioning as intended. Also as used herein, the terms “substantially,” “generally,” “approximately,” and “about” are intended to mean that slight deviations from absolute are included within the scope of the term so modified.
[0024]
[0025] A dashed arrow, labeled “TA”, indicates a transapical approach of implanting a prosthetic heart valve, in this case to replace the mitral valve. In the transapical approach, a small incision is made between the ribs of the patient and into the apex of left ventricle LV to deliver the prosthetic heart valve to the target site. A second dashed arrow, labeled “TS”, indicates a transseptal approach of implanting a prosthetic heart valve in which the delivery device is inserted into the femoral vein, passed through the iliac vein and the inferior vena cava into right atrium RA, and then through the atrial septum into left atrium LA for deployment of the valve. Other approaches for implanting a prosthetic heart valve are also possible and may be used to implant the collapsible prosthetic heart valve described in the present disclosure.
[0026]
[0027]
[0028] Prosthetic heart valve 10 includes an inner stent 12 securing a valve assembly 14, an outer stent 16 attached to and disposed around the inner stent, and a tether 18 configured to be secured to an apical pad 20. Both the inner stent 12 and the outer stent 16 may be formed from biocompatible materials that are capable of self-expansion, for example, shape-memory alloys such as nitinol. Alternatively, inner stent 12 and/or outer stent 16 may be balloon expandable or expandable by another force exerted radially outward on the stent. When expanded, outer stent 16 folds upon itself to form a flange that engages an atrial surface of the native valve annulus and assists in anchoring inner stent 12 and valve assembly 14 within the native valve annulus when tether 18 is tensioned.
[0029] Referring to
[0030] With additional reference to
[0031] Referring now to
[0032] The first foldable portion 46, the second foldable portion 48 and the body portion 52 of outer stent 16 may include a plurality of struts 56 that form cells 58 extending about the outer stent in one or more annular rows. Cells 58 may be substantially the same size around the perimeter of stent 16 and along the length of the stent. Alternatively, cells 58 within the body portion 52 and closer to the atrial end 42 of outer stent 16 may be larger than the cells within the body portion near the ventricular end 44 of the stent. The attachment features 50 may extend from the struts 56 forming apices of adjacent cells 58 that lie within the ventricular-most row of cells of outer stent 16. Attachment features 50 may define an eyelet 60 that facilitates the suturing (or connection via another fastener or attachment mechanism) of outer stent 16 to the longitudinal posts 34 of inner stent 12, thereby securing the inner and outer stents together. In one example, attachment features 50 may be sutured to a single bore 36 of a longitudinal post 34, proximate to the outflow end 24 of inner stent 12.
[0033] With additional reference to
[0034] As shown in
[0035] In a preferred embodiment, a sealing cuff 66 is disposed on a surface of flange 54 that engages an atrial surface of the native mitral valve annulus when prosthetic heart valve 10 is implanted within the native mitral valve. Sealing cuff 66 may be formed of a fabric, or a biologic or synthetic tissue, to seal the space between prosthetic heart valve 10 and the native mitral valve annulus. In one example, the material of sealing cuff 66 may be segmented into a plurality of discrete pieces, each of which is sutured or otherwise secured to struts 56 forming a single cell 58 or, alternatively, to the struts forming a perimeter around a relatively few number of cells. In this regard, each of the discrete pieces can flex relative to one another so as to not inhibit the bending of first foldable portion 46 and second foldable portion 48 relative to body portion 52. Alternatively, sealing cuff 66 may be formed of a single piece of material if the material is stretchable or otherwise does not inhibit outer stent 16 from transitioning from the delivery condition to the deployed condition and the formation of flange 54.
[0036] With specific reference to
[0037] Systolic Anterior Motion (SAM) prevention features may optionally be provided, for example, on outer stent 16. SAM (e.g., the displacement of the free edge of native anterior leaflet AL toward left ventricular outflow tract LVOT) can result in severe left ventricular outflow tract LVOT obstruction and/or mitral regurgitation. To prevent the occurrence of SAM, or at least significantly reduce its likelihood, a pivot arm 68 (shown in
[0038] In a preferred embodiment, as shown in
[0039] Use of prosthetic heart valve 10 to repair a malfunctioning native heart valve, such as a native mitral valve, or a previously implanted and malfunctioning prosthetic heart valve, will now be described with reference to
[0040] With a first end of tether 18 secured to the clamp 32 of inner stent 12, a physician may pull the free end of the tether through a loading device (not shown), such as a funnel, to crimp or collapse inner stent 12 and transition outer stent 16 from the expanded or deployed condition to the collapsed or delivery condition. After prosthetic heart valve 10 has been collapsed, the prosthetic heart valve may be loaded within a delivery device 100 with the free end of tether 18 extending back towards the trailing end (not shown) of the delivery device such that it can be manipulated by a physician.
[0041] After an incision has been made between the ribs of the patient and into the apex of the heart, delivery device 100 may be introduced into the patient using a transapical approach and delivered to an implant site adjacent the native mitral valve annulus. Once delivery device 100 has reached the target site, with a leading end 102 of delivery sheath 104 disposed within left atrium LA, the delivery sheath may be retracted to expose the atrial end 42 of outer stent 16, thereby allowing outer stent 16 to expand and transition from the delivery condition to the deployed condition.
[0042] As shown in
[0043] In the event that the physician determines that the valve assembly 14 is malfunctioning or that prosthetic heart valve 10 is positioned incorrectly within the native mitral annulus, the physician may recapture the prosthetic heart valve. To recapture prosthetic heart valve 10, the physician may pull tether 18 toward the trailing end of delivery device 100 thereby retracting the prosthetic heart valve and engaging the strut portion 30 of inner stent 12 against the leading end 102 of delivery sheathe 104 to crimp the inner stent, and with it outer stent 16, to a diameter capable of being inserted into the leading end the delivery sheathe. If valve assembly 14 was working as intended, but prosthetic heart valve 10 was mispositioned within the native mitral valve annulus, the physician may only need to partially collapse the prosthetic heart valve within delivery device 100 before repositioning the delivery sheathe with respect to the native mitral annulus and redeploying the prosthetic heart valve as previously described. Alternatively, if valve assembly 14 was malfunctioning, prosthetic heart valve 10 may be completely recaptured and removed from the patient. The physician may then repeat the procedure described above with a different prosthetic heart valve 10.
[0044] In some instances, the physician may find it desirable to secure the native anterior leaflet AL of native mitral valve MV to the outer stent 16 of prosthetic mitral valve 10 to prevent SAM. When desired, the physician may use prosthetic heart valve 10 having a pivot arm 68, which when unsheathed and when tension is released from suture 73, will automatically pivot from the collapsed condition to an expanded condition to secure the native leaflet to prosthetic heart valve 10 and away from the left ventricular outflow tract.
[0045] After the physician has confirmed that prosthetic heart valve 10 has been properly positioned, and leaflets 40 are properly coapting, the physician may insert apical pad 20 through the incision before coupling tether 18 and apical pad 20 and tensioning the tether. As shown in
[0046] Apical pad 20, which may be positioned in contact with an exterior surface of left ventricle LV at the transapical puncture site, may then be locked to tether 18, preventing the tether from releasing the tension. The physician may then cut the tether located outside of the heart before removing the cut portion of the tether and delivery device 100 from the patient. With prosthetic heart valve 10 properly positioned and anchored within the native mitral valve annulus of a patient, the prosthetic heart valve may work as a one-way valve to restore proper function of the heart valve by allowing blood to flow in one direction (e.g., from the left atrium to the left ventricle) while preventing blood from flowing in the opposite direction.
[0047] Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims.