DEVICES, SYSTEMS AND METHODS FOR PREVENTING PROLAPSE OF NATIVE CARDIAC VALVE LEAFLETS

Abstract

A collapsible and expandable prosthetic heart valve stent is provided and comprising an outer section, a valve support defining a flow channel therethrough, a transition section configured to smoothly transition the outer section to the valve support. The valve support is disposed within an interior defined by the outer section, with the inflow end of the valve support disposed inside the outer section's interior. In some cases, the outflow end of the valve support is at least partially defined by the transition section. The prosthetic leaflets are disposed on the inner surface of the valve support's flow channel and are located at or above the annulus of the heart chamber. A prolapse prevention system is attached to the stent to mitigate native valve leaflet prolapse.

Claims

1. A collapsible and expandable stent for implanting into a right atrium of a patient's heart comprising: an expanded ball-shaped outer section comprising an outer surface, an inner surface, and defining an interior; an inner valve support extending upward into the interior of the outer section and comprising an inflow end and an outflow end, wherein the inflow end is superior to the outflow end when the stent is implanted, the inner valve support comprising an inner surface defining a flow channel between the inflow and outflow ends, the inner valve support positioned entirely within the interior of the outer section; a plurality of prosthetic valve leaflets disposed within the flow channel defined by the inner valve support section, wherein the prosthetic valve leaflets are configured to allow flow from the inflow end to the outflow end of the flow channel and prevent flow from the outflow end of the flow channel to the inflow end of the flow channel; a collapsible and expandable transition section comprising a plurality of cells extending between the expanded ball-shaped outer section and the inner valve support, wherein the inner valve support extends radially upward into the interior of the outer section, the transition section comprising an outer surface and an inner edge that faces the interior defined by the expanded ball-shaped outer section, wherein the expanded ball-shaped outer section, the transition section and the inner valve support are a single unitary stent structure formed of a continuous series of stent cells; and two semi-circular leaf guards comprising an upstream and a downstream end, wherein each semi-circular leaf guard is connected at the upstream end with the inner surface of the valve support at an outflow end of the valve support, wherein the semi-circular leaf guards are radially spaced away from each other, wherein each leaf guard extends away from the valve support in a downstream direction, wherein the plurality of prosthetic valve leaflets are disposed and spaced away in an upstream direction from the two semi-circular leaf guards.

2-6. (canceled)

7. A collapsible and expandable stent for implanting into at least one chamber of a patient's heart comprising: an outer section comprising an outer surface, an inner surface, and defining an interior; a valve support extending radially upward into the interior of the outer section and comprising an inflow end and an outflow end, the inflow end extending radially upward into the outer section, the valve support comprising an inner surface defining a flow channel between the inflow and outflow ends, the valve support positioned entirely within the interior of the outer section; a plurality of prosthetic valve leaflets disposed within the flow channel defined by the valve support section, wherein prosthetic valve leaflets are configured to allow flow from the inflow end to the outflow end of the flow channel and prevent flow from the outflow end of the flow channel to the inflow end of the flow channel; a collapsible and expandable transition section comprising a plurality of cells extending between the outer section to the valve support, wherein the valve support extends radially upward into the interior of the outer section, the transition section comprising an outer surface and an inner edge that faces the interior defined by the outer section; and a prolapse prevention structure comprising a plurality of round or flat spanning elements connected to, or integrated with, with the stent and configured to extend across the flow channel defined by the inner valve support.

8. The stent of claim 7, wherein the plurality of round or flat spanning elements are connected to, or integrated with, the outflow end of the inner valve support.

9. The stent of claim 7, wherein the plurality of round or flat spanning elements are connected to, or integrated with, the inner edge of the transition section.

10. The stent of claim 7, wherein the plurality of round or flat spanning elements are disposed transverse to a flow of blood through the flow channel defined by the inner valve support.

11. The stent of claim 7, wherein at least one of the round or flat spanning elements are adapted to engage native leaflets of a native valve within the at least one chamber of the patient's heart only at point where normal healthy coaptation would normally occur.

12. The stent of claim 7, wherein the plurality of round or flat spanning elements comprises a screen or mesh.

13. (canceled)

14. The stent of claim 1, wherein the outflow end of the inner valve support does not extend outwardly past the transition section.

15-20. (canceled)

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0021] FIG. 1 illustrates certain features of the heart in cross-section.

[0022] FIG. 2 illustrates a cross-sectional perspective view of the left side of the heart.

[0023] FIG. 3 illustrates a cross-sectional view of the heart showing retrograde blood flow resulting from mitral valve regurgitation compared with normal blood flow.

[0024] FIG. 4 illustrates and end view of one embodiment of a valve support.

[0025] FIG. 5 illustrates a perspective view of one embodiment of a prosthetic heart valve stent device.

[0026] FIG. 6 illustrates a partial cross-sectional view of one embodiment of a prolapse prevention system of the present invention.

[0027] FIG. 7 illustrates a partial cross-sectional view of one embodiment of a prolapse prevention system of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0028] Generally, various embodiments of the present invention are directed to devices and methods for creating optimal apposition of a support structure or stent of a prosthetic heart valve to treat cardiac mitral or tricuspid valve regurgitation, mitigating paravalvular leak and optimizing functional efficiency of the prosthetic heart valve.

[0029] The support structure (i.e. stent) has multiple features that function to aid with the treatment of cardiac valve regurgitation (mitral or tricuspid). These functions include its function as a scaffold for the functioning prosthetic valve leaflets of the current invention, apposition to the atrial anatomy, optimized radial force for compliance with atrial distension, ability to load and deploy from a minimally invasive delivery system, and geometry to support with mitigating against paravalvular leak (PVL). The design features of the stent are adapted to meet one or more of the functions identified above. Specific design features and attributes for the stents are discussed in detail below.

[0030] The stent design concepts are intended to support minimally invasive procedures for the treatment of valvular regurgitation — mitral, tricuspid and/or otherwise. The stents may be self-expandable (e.g. nitinol or similar materials) or balloon expandable (e.g. cobalt chromium or similar materials). The stents are made of cells that may be open celled diamond like structures or continuous structures that have a working cell element. The stents may also be constructed using tubing, wires, braids or similar structures. Specific design features that aid with the functioning of the stent are described in detail below.

[0031] Referring to FIG. 5, an expandable and collapsible prosthetic heart valve stent device 100 may comprise an outer section 102—that may generally look like a ball when undeformed and fully expanded and an inner valve support section 104, adapted to support and retain prosthetic valve leaflets 106, shown in FIGS. 6 and 7, within the inner valve support section 104, most preferably at a point that is located above the native annulus, and spaced away or above the native leaflets, as shown in FIGS. 6 and 7, though other attachment points for the prosthetic leaflets 106 are within the scope of the present invention. Inner valve support 104 may be cylindrical, but in a preferred embodiment may also be at least partially conical, with a larger diameter at an outflow end 0 than the diameter across at least portions of an inflow end I, wherein the inflow end I is disposed radially inside the outer frame section and wherein the outflow end 0 may define a lower end or edge of the valve support 104. Thus, in a purely conical arrangement, the valve support section 104 may comprise a smoothly decreasing diameter thereacross and this smooth diameter decrease may extend from the outflow end O to the inflow end I. In other embodiments, the inflow end I may comprise one or more lobes extending radially outwardly and that interrupt the smooth conical profile. A preferred embodiment in this regard provides one lobe for each prosthetic leaflet 106 attached within the inner valve support 104 to allow for fuller freedom of movement and improved coaptation.

[0032] FIG. 4 illustrates an end view of one embodiment of an inflow end I of the inner valve support 104 comprising three lobes L. See also commonly assigned US patent application 62/612,836, filed Jan. 2, 2018, the disclosure of which is hereby incorporated in its entirety.

[0033] A preferred construction comprises the prosthetic leaflets 106 disposed or spaced above the native leaflets when the prosthetic heart valve stent device 100 is implanted, wherein the prosthetic leaflets 106 are attached and spaced sufficiently away from (above) the native leaflets so as to not physically interfere or interact with the native leaflets. However, certain embodiments contemplate some interaction with the native leaflets.

[0034] The layer of stent cells that transition from the outer section to the inner section of the stent are termed as transition cells forming a transition section 108 generally as illustrated in FIG. 5.

[0035] The outer and inner sections of the stent may be constructed from one continuous structure or may combine two or more structures to achieve intended design goals. As known in the art, stent structures may be formed using complementary shaped mandrels, including the outer section 102 of the stent, the transition section 108, and the inner valve support 104—including lobes L discussed above in certain embodiments- as a single unitary structure.

[0036] Referring now to FIG. 6, an exemplary prosthetic heart valve stent device 100 is shown implanted within the left atrium. The prosthetic valve leaflets 106 are shown as elevated above the upper annular surface of the left atrium and generally located or centered above the annulus between the left atrium and left ventricle and comprises a prolapse prevention structure 200. An exemplary screen or mesh prolapse prevention structure 200 is shown that extends across the interior flow channel defined by the inner valve support 102 from inflow end Ito outflow end O and covers at least partially the native annulus. The screen or mesh prolapse prevention structure 200 may be connected to, or integrated with, the outflow end of the inner valve support 104 and/or may be connected generally at an inner edge of the transition section 108. The exemplary prolapse prevention structure 200 of FIG. 6 is positioned at a point axially relative to the native leaflets NL and their normal healthy functional coaptation point so as to engage the native leaflets NL at that coaptation point to prevent as much regurgitation as possible using the native leaflets NL and without unnecessarily engaging the supra-annularly positioned prosthetic leaflets 106 for that task, while preventing prolapse of the native leaflets NL.

[0037] In certain embodiments the prolapse prevention structure 200 may comprise a coating comprising anti-thrombus formation compound(s) and/or anti-endothelization compound(s).

[0038] The exemplary prolapse prevention structure 200 of FIG. 6 may comprise a plurality of round or flat spanning elements or sections E that extend across and engage an outer support structure F that is engaged with the implanted prosthetic valve structure as described above. Outer support structure F may be shaped and sized to fit the shape and size of the portion of the inner valve support 102 to which it is connected or integrated with.

[0039] In certain embodiments, the outer support structure F may be positioned generally so that it engages with tissue and works to prevent paravalvular leakage (PVL). For example, the outer support structure of the prolapse prevention structure may engage, or be integrated with, the transition section described above to provide a barrier against PVL.

[0040] Further in this regard, a preferred embodiment of the device shown in the Figures comprises a skirt S, comprising fabric or tissue, disposed along a portion of the outer surface of the outer frame element 102 and that extends along the outer surface of the transition section 108 and along the inner surface, or inwardly facing surface, of the inner valve support 102 so that the skirt S is facing the flow channel defined therein from the inflow end Ito the outflow end 0. In certain embodiments, the outer support structure F of the prolapse prevention structure 200 may also be covered with a fabric or tissue that, in combination with the tissue engagement of the outer frame and transition elements, may assist in preventing PVL.

[0041] Alternatively, the spanning elements or sections E may be integrated with the prosthetic heart valve stent device 100 as described above without aid or requirement of an outer support structure.

[0042] Generally the spanning elements or sections E may be disposed transverse to the blood flow through the inner valve support 104. In the case of an outer support structure F, the spanning elements or sections E may be substantially coplanar with the outer support structure F or, alternatively may extend either upwardly or downwardly from the outer support structure F. All such exemplary structures are acceptable so long as the native leaflets NL are engaged by at least one spanning element or section E at a point of normal healthy functional coaptation. Thus, the outer support structure F may be located at a point above the normal coaptation point, wherein at least one spanning element or section extends therebelow to the normal coaptation point.

[0043] Turning now to FIG. 7, another exemplary embodiment of a prolapse prevention structure 200′ is illustrated. Here, instead of a circular support structure, two leaf guards 200′ are positioned as aligned with the two native leaflets of the mitral valve and having a distal end that is positioned to engage the native leaflets NL. The leaf guards 200′ may be connected to, or integrated with the inner valve support 104 or may be connected to, or integrated with, the transition section 108. In this embodiment, the leaf guards 200′ are disposed at or below the upper annular surface and reach a distance into the annulus. In some embodiments the leaf guards 200′ are arranged so as to not engage the native leaflets until they reach the point of normal healthy coaptation.

[0044] Alternatively, the leaf guards 200′ may effectively pin the native leaflets as shown in FIG. 7, so that the implanted prosthetic valve device 100 immediately becomes a full replacement device. The leaf guards 200′ of FIG. 7 are shown as comprising a semi-circle, wherein an upstream end of each of the leaf guards 200′ is connected within the inner surface of the inner valve support 102 at the outflow end 0 of the inner valve support 102. The leaf guards 200′ are radially spaced from each other around the inner valve support 102 to enable the leaf guards 200′ to align with, and engage, the two native leaflets when the device is implanted into the patient's right atrium. Leaf guards 200′ in FIG. 7 each extend from the inner valve support 102, in the downstream direction along the annulus and comprise an inner portion that effectively curves or wraps around the native mitral valve annulus to engage the native leaflets. The inner portion of the leaf guards 200′ of FIG. 7 comprise a slightly smaller radius than the outer portion of the leaf guards 200′. The outer, larger radius, portion of the leaf guards 200′ is exposed to blood flow within the mitral valve annulus.

[0045] As shown in FIG. 7, and in equivalent embodiments, the leaf guards 200′ may be configured to provide a positioning and locating function that allows alignment of the inner valve support 104 and prosthetic leaflets 106 held therein over the native annulus and native leaflets during implantation and subsequent operation. In this regard, the leaf guards 200′ may function in two key ways: prolapse prevention or pinning of the leaflets, and alignment, locating and positioning of the prosthetic heart valve stent device 100 when implanted.

[0046] An alternative embodiment to individual leaf guards 200′ may comprise one or more semi-circular leaf guard extensions, of a number and at a position that comports with the number of native leaflets and their general position. These semi-circular leaf guards 200′ may be positioned to (1) only engage native leaflets at the normal healthy coaptation point; or (2) effectively pin the native leaflets. In either case, the semi-circular leaf guards 200′ may be configured to, as described above, assist with positioning, locating and aligning the prosthetic valve device relative to the annulus. Further, as discussed above, the semi-circular leaf guards 200′ may be at least partially covered with a tissue or fabric that may be coextensive or connected with the skirt material of the outer frame, transition section and/or inner valve to assist in preventing PVL.

[0047] A still more alternative embodiment may comprise a leaf guard extension comprising an unbroken structure extending from the inner valve support 104 and/or transition section 108, the unbroken structure taking an expanded shape that may be substantially circular and/or may substantially match the shape of the annulus. Again, the unbroken leaf guard extension may be configured to, as described above, assist with positioning, locating and aligning the prosthetic heart valve stent device 100 relative to the annulus and may either engage the native leaflets NL at a normal healthy coaptation point or may work to pin the native leaflets NL. Further, as discussed above, the unbroken leaf guard extension may be at least partially covered with a tissue or fabric that may be coextensive or connected with the skirt material of the outer frame 102, transition section 108 and/or inner valve support 104 to assist in preventing PVL.

[0048] In certain embodiments, at least a lower portion of the leaf guards 200′ may be relatively flexible and responsive to the pressure and fluid flow changes, while prevented from flexing upwardly past a coaptation point. Thus, during systole, the lower portion of the leaf guards 200′ may be urged to extend radially inwardly to engage the rising native leaflets at a normal healthy coaptation point. During diastole, the lower portion of the leaf guards 200′ may be urged to substantially straighten or be otherwise positioned to allow blood flow therealong such as may be seen with reference to FIG. 7.

[0049] In some cases, the prolapse prevention structure 200 of FIG. 6, and the prolapse prevention structure comprising the leaf guards 200′ of FIG. 7 may be constructed to provide a second prosthetic valve, wherein they may, in response to the pressure and fluid flow changes discussed above, effectively open and close at least partially to further assist in preventing regurgitation. In this way, the prolapse prevention structure 200 of FIG. 6, and the prolapse prevention structure comprising the leaf guards 200′ of FIG. 7 may be viewed as the initial regurgitation barrier, in combination with the native leaflets, with the prosthetic leaflets functioning to stop any additional regurgitant. If, or when, the native leaflet function deteriorates nearly completely, the combination of the prolapse preventing structure 200 of FIG. 6, or the prolapse prevention structure comprising the leaf guards 200′ of FIG. 7, and the prosthetic leaflets 106 may work together to form a two-stage prosthetic staged set. This staging of regurgitant flow stoppage may work to extend the life of the native leaflets.

[0050] It is noteworthy that the various embodiments of the presently described prosthetic valve stent device 100 may be delivered percutaneously via one of at least the following known access and delivery routes: femoral access, venous access, trans-apical, trans-aortic, trans-septal, and trans-atrial, retrograde from the aorta delivery techniques. Alternatively, the prosthetic valve stent device 100 may be delivered and implanted using surgical and/or open heart techniques.

[0051] The description of the invention and its applications as set forth herein is illustrative and is not intended to limit the scope of the invention. Features of various embodiments may be combined with other embodiments within the contemplation of this invention. Variations and modifications of the embodiments disclosed herein are possible, and practical alternatives to and equivalents of the various elements of the embodiments would be understood to those of ordinary skill in the art upon study of this patent document. These and other variations and modifications of the embodiments disclosed herein may be made without departing from the scope and spirit of the invention.