Docking components

Abstract

Devices and methods are described, including a docking element (20) configured to be implanted in the left atrium of a subject such that no portion of the docking element (20) extends through the mitral valve of the subject. The docking element (20) includes a ring (40); a frame (24) extending upward from the ring (40); and a radial protrusion (50) configured to extend radially outward from the frame to be disposed adjacent to the subject's native mitral valve annulus and to produce tissue ingrowth from the wall of the left atrium to the radial protrusion at least adjacent to the subject's native mitral valve annulus. A bridging material (56) disposed between the radial protrusion (50) and the ring (40) forms a seal between the radial protrusion (50) and the ring (40). Other applications are also described.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Provisional Application No. 62 / 909,787, filed on October 3, 2019, by Benichou et al., entitled “Docking elements,” which is incorporated herein by reference.

[0003] Field of Embodiments of the Invention

[0004] Some applications of the present invention relate generally to medical devices and methods. In particular, some applications of the present invention relate to devices and methods for use with prosthetic mitral valves.

[0005] background

[0006] The atrioventricular valves are heart valves that prevent backflow from the ventricles to the atria during systole. They are anchored to the heart wall at the fibrous skeleton by anchoring tendons (named chordae tendineae). The chordae tendineae are attached to the papillary muscles. The papillary muscles and chordae tendineae together prevent the valves from prolapsing into the atria when they are closed during systole. The actual opening and closing of the valves is caused by the pressure gradient across the valves. The left atrioventricular valve is a bicuspid valve with two leaflets, commonly known as the mitral valve. The right atrioventricular valve is a tricuspid valve with three leaflets. Both valves may be damaged and dysfunctional, resulting in leakage during systole, requiring valve repair or replacement.

[0007] The mitral valve is usually oval or D-shaped, while the tricuspid valve is more rounded. The left ventricle pumps oxygenated blood to the body, and therefore the mitral valve must withstand higher pressures than the tricuspid valve, which only has to pump deoxygenated blood to the nearby lungs.

[0008] Occasionally, the mitral valve may be congenitally abnormal or damaged by infection or bacterial endocarditis. More commonly, the mitral valve degenerates with age or due to rheumatic fever. There are different heart valve diseases associated with the mitral valve, such as mitral stenosis and mitral regurgitation. In the case of mitral stenosis, due to calcium nodules, leaflet thickening and / or reduced leaflet mobility, the valve orifice, i.e., the cross-section available for blood to pass through, is reduced, and therefore the valve does not allow normal blood flow. In order to overcome the damaged valve and transport an equal amount of blood, the left atrium requires a higher pressure than normal. The continuous pressure overload of the left atrium may cause its size to increase and become more susceptible to atrial fibrillation and loss of atrial kick. The loss of atrial kick caused by atrial fibrillation can lead to a sharp decrease in cardiac output. The reduction in cardiac output, accompanied by an accelerated heart rate and a shortened diastolic time, often leads to congestive heart failure. In most cases, mitral stenosis is caused by rheumatic heart disease. Treatment options for mitral stenosis include medical management, surgical repair, surgical replacement of the valve, and percutaneous balloon valvuloplasty.

[0009] Mitral regurgitation causes a heart murmur and can have serious physiological consequences. Mitral regurgitation is caused by ischemic heart disease (such a condition is called "ischemic mitral regurgitation") or mitral valve prolapse. Ischemic mitral regurgitation is the result of ventricular remodeling secondary to ischemic heart disease. The posterior wall of the heart, which is not attached to the fibrous skeleton of the heart, dilates. Due to changes in the geometry of the left ventricle, the posterior leaflet attached to the posterior wall of the heart is displaced and deviates from the anterior leaflet, which causes mitral regurgitation.

[0010] Mitral valve prolapse is a condition caused by degeneration of the connective tissue of the valve. Patients with typical mitral valve prolapse have excess connective tissue. This weakens the leaflets and adjacent tissues, resulting in increased leaflet area and elongation of the chordae tendineae. Elongation of the chordae tendineae often leads to rupture. The twisted leaflets may displace portions of one or both abnormally thickened mitral leaflets into the left atrium during systole. Advanced disease causes the leaflets to fold, invert, and shift toward the left atrium. The abnormal leaflet structure leads to incomplete closure of the mitral valve, which in turn causes mitral regurgitation.

[0011] In mitral regurgitation, the heart has to work harder to pump not only the regular volume of blood but also the extra volume of blood that is flowing back into the left atrium. The increased workload places excessive strain on the left ventricle, which can lead to heart failure.

[0012] Although patients with mild to moderate mitral regurgitation caused by mitral valve prolapse may not experience symptoms, the increasing severity of mitral regurgitation, even in the absence of symptoms, increases the load on the left ventricle. Over time, this can lead to ventricular dilation and congestive heart failure.

[0013] Mitral valve disease is usually treated by open heart surgery, via surgical repair, usually using an annuloplasty ring, or via surgical replacement with a prosthetic valve. In some cases, such as when the valve is too damaged, the mitral valve may need to be replaced. Mitral valve replacement can be performed automatically or manually. Surgical valve replacement or repair is usually a demanding procedure because it requires cardiopulmonary bypass and it can expose the patient, especially the elderly, to many risks.

[0014] A wide variety of percutaneous or transcutaneous medical procedures are currently being developed and / or implemented. For example, known transcatheter procedures are used to replace aortic and pulmonary heart valves. These procedures, which are performed in a cardiac catheterization laboratory under local anesthesia rather than by cardiac surgery, provide benefits to these patients. According to such a method, the valve is inserted into a delivery device similar to a catheter or sheath, and then implanted in a desired position via a passage through a large blood vessel such as, for example, the femoral artery. This includes making a very small perforation on the patient's skin, such as in the groin area, in order to access the femoral artery. This minimally invasive option is generally safer than open heart surgery, and recovery time is generally shorter.

[0015] Overview of Embodiments

[0016] According to some applications of the present invention, the docking element is configured to facilitate anchoring of a prosthetic mitral valve device to a mitral valve of a subject.The docking element is typically disposed in its entirety within the left atrium and does not extend into the left ventricle.

[0017] Typically, the prosthetic mitral valve device is a stent valve, which includes a stent frame configured to support the prosthetic valve leaflets. Typically, the stent frame is covered with a material (e.g., a fabric such as PET, PTFE and / or nylon). The prosthetic mitral valve device is typically implanted in the natural mitral valve of a subject with a diseased natural valve, and the prosthetic valve leaflets function to replace the function of the natural valve leaflets. Typically, the prosthetic valve leaflets are configured to act as a one-way valve, whereby when they are in an open position relative to each other, the leaflets allow flow to pass through the prosthetic valve device from the inlet (on the atrial side) to the outlet (on the ventricular side), and because the collapsible slack portion of the valve leaflets contracts inwardly to block reverse flow, reverse flow is prevented.

[0018] Typically, the docking element is implanted in the left atrium more than one week or more than one month prior to implanting the prosthetic mitral valve device. After implantation of the docking element and before implantation of the prosthetic mitral valve device, the anchoring of the docking element is typically enhanced by tissue ingrowth occurring around the docking element, such as described below. Typically, no portion of the docking element extends through the subject's native mitral valve. Furthermore, typically, due to the fact that no portion of the docking element extends through the subject's native mitral valve, the native mitral valve leaflets are able to continue to function in their normal manner after implantation of the docking element and before implantation of the prosthetic mitral valve device.

[0019] For some applications, the docking element includes a frame and a ring coupled to the frame. Typically, with the ring in a deployed state inside the left atrium, the ring is disposed laterally relative to the frame such that a plane defined by the ring is substantially parallel to a longitudinal axis of the frame. For some applications, the ring is configured to be disposed at a height flush with, slightly above, or slightly below the height of the mitral valve annulus, and the outer perimeter of the ring is smaller than the perimeter defined by the mitral valve annulus, such that the ring "floats" above the native valve leaflets. These applications of the present invention will be described in further detail below.

[0020] Typically, the frame is made of a self-expandable shape memory material (e.g., a shape memory alloy, such as Nitinol), and the frame is cut and shaped to define more than one cell defined by struts of the shape memory material. Alternatively or additionally, the frame is assembled from wires made of a self-expandable shape memory material (e.g., a shape memory alloy, such as Nitinol). Typically, the portion of the frame closest to the ring is covered by a skirt of a material that facilitates tissue ingrowth into the frame. For example, the skirt can be made of a fabric (such as PET, PTFE and / or nylon) and can be connected to the outside of the frame and / or the ring using sutures. Typically, a portion of the frame configured to be disposed near the mitral annulus (e.g., at the mitral annulus and / or slightly above the mitral annulus (e.g., within 15 mm of the mitral annulus)) is covered by a skirt. For some applications, the skirt is configured to be disposed from between 1 mm and 2 mm above the mitral annulus (or from the height of the mitral annulus) to a height between 15 mm and 20 mm above the mitral annulus.

[0021] For some applications, the docking element includes a radial protrusion that extends radially from the frame (typically above the ring and / or flush with the ring). For example, the radial protrusion can be shaped as a flap and / or a torus disposed around the circumference of the frame. Typically, the protrusion is configured to contact the wall of the left atrium and promote tissue to grow inwardly from the wall of the left atrium to the protrusion. For some applications, the radial protrusion is configured to conform to the shape of the atrial wall near the mitral valve annulus so that the protrusion fills any gap between the outside of the frame and the atrial wall near the mitral valve annulus. Therefore, due to tissue inward growth, the docking element typically becomes anchored to the wall of the left atrium. For some applications, the protrusion is configured to act as a bridge for tissue inward growth, and the protrusion is configured to promote tissue to grow inwardly from the wall of the left atrium, through the protrusion, and into the skirt and / or into the frame. Typically, the protrusion is configured to contact the wall of the left atrium near the mitral annulus, for example, at the height of the mitral annulus, and / or at a height from between 1 mm and 2 mm above the mitral annulus up to between 15 mm and 20 mm above the mitral annulus.

[0022] Typically, the outer perimeter of the ring is smaller than the size of the inner perimeter of the radial protrusion. Further typically, there is a bridging material (e.g., a fabric) that bridges between the ring and the radial protrusion and forms a seal between the ring and the radial protrusion. Usually, the bridging material that bridges between the ring and the radial protrusion is part of the skirt. According to the above description, for some applications, the docking element includes a combination of the following three components: 1) a radial protrusion that is configured to anchor to tissue near the mitral valve annulus via tissue ingrowth, 2) a ring to which the prosthetic mitral valve device is configured to anchor, and 3) a bridging material that bridges between the two elements and forms a seal between the two elements.

[0023] For some applications, the radial protrusion is self-expandable and includes a coil spring (the coil spring is typically made of a self-expandable metal or alloy, such as Nitinol) covered with a fabric (such as PET, PTFE and / or nylon) that is configured to promote tissue ingrowth. According to various embodiments, the coil spring is a rounded spiral, a triangular spiral, or a spiral of a different shape. The coil spring is configured to extend the self-expanding protrusion radially outward from the outer surface of the frame so that the protrusion conforms to the anatomical structure of the left atrium in areas where the frame itself is not flexible enough. In this way, the self-expandable protrusion fills the gap between the outside of the frame and the wall of the left atrium.

[0024] Typically, the radial protrusions extend radially outwardly from the outer surface of the frame around more than 70% (eg more than 90%) of the circumference of the frame.Furthermore, typically, the protrusions extend radially outwardly from the outer surface of the frame around the entire circumference of the frame.

[0025] For some applications, the docking element includes a frame, a ring, a skirt, and a radial protrusion. The radial protrusion is configured to extend to the wall of the left atrium near the natural mitral valve annulus (e.g., at its height or slightly higher (e.g., within 15 mm of the height)), and promote tissue to grow inward from the left atrium of the subject to the docking element, for example, tissue grows inward to the radial protrusion itself, and / or tissue grows inward to the frame and / or skirt via the radial protrusion. A portion of the skirt serves as a bridging material and bridges and seals between the radial protrusion and the ring, so that the bridging material occupies and seals a portion of the area defined by the natural mitral valve annulus. Therefore, the ring acts as an artificial mitral valve annulus that is smaller than the natural mitral valve annulus.

[0026] Thus, according to some applications of the present invention, there is provided an apparatus for treating a subject having a diseased mitral valve, the apparatus comprising:

[0027] A docking element configured to be implanted within a left atrium of a subject such that no portion of the docking element extends through a mitral valve of the subject, the docking element comprising:

[0028] ring;

[0029] a frame extending upwardly from the annulus, the frame being configured to anchor the docking element within the left atrium by expansion of the frame against at least one of a wall of the left atrium and a roof of the left atrium before tissue ingrowth into the docking element occurs,

[0030] a radial protrusion configured to extend radially outward from the frame to be disposed adjacent to a native mitral valve annulus of the subject and to produce tissue ingrowth from a wall of the left atrium to the radial protrusion at least adjacent to the native mitral valve annulus of the subject; and

[0031] a bridging material disposed between the radial protrusion and the ring, the bridging material forming a seal between the radial protrusion and the ring; and

[0032] A prosthetic mitral valve device, the prosthetic mitral valve device being configured to:

[0033] After tissue ingrowth from the wall of the left atrium to the radial projection occurs, at least partially positioned within the interior of the docking element, and

[0034] Becoming anchored to the docking element at least in part by expanding radially against the ring.

[0035] In some applications, the radial protrusions are configured to extend radially outward from the frame at a level with the ring.

[0036] In some applications, the radial protrusions are configured to extend radially outward from the frame at a height between 1 mm and 20 mm above the ring.

[0037] In some applications, the radial protrusions are configured to conform to the shape of a wall of the left atrium near the mitral valve annulus such that the radial protrusions fill any gaps between an exterior of the frame and the wall of the left atrium near the mitral valve annulus.

[0038] In some applications, the size of the annulus is smaller than the size of the subject's mitral valve annulus.

[0039] In some applications, the radial protrusions are configured to generate tissue ingrowth into the radial protrusions from a wall of the left atrium toward the frame at least near a native mitral valve annulus of the subject.

[0040] In some applications, the radial protrusion comprises a flange.

[0041] In some applications, the radial protrusion comprises an annular convex radial protrusion.

[0042] In some applications, the radial protrusions have an oval shape.

[0043] In some applications, the radial protrusions are configured to extend radially outward from the frame around more than 70% of the circumference of the frame.

[0044] In some applications, the docking element further comprises a skirt covering a portion of the frame extending from the ring to a height of at least 5 mm on the frame from the ring, and the bridging material comprises a portion of the skirt.

[0045] In some applications, the radial protrusion is configured to generate tissue ingrowth into the radial protrusion from the wall of the left atrium toward the skirt at least near the native mitral valve annulus of the subject.

[0046] In some applications, the radial protrusions are configured to be self-expanding.

[0047] In some applications, the radial protrusions include spirals covered with a covering material.

[0048] In some applications, the frame includes struts connected to each other at joints to define the cells, and near the joints, at least some of the struts are shaped to define undulating and / or zigzag regions.

[0049] In some applications, by being formed to define undulating and / or zigzag regions, the effective strut length of the struts is elongated near the joint so that strains occurring near the joint will be spread over a greater effective length than if the struts were not formed to define undulating and / or zigzag regions.

[0050] In some applications, the frame includes struts connected to each other at joints to define a grid, and at least some of the struts are arranged to define groups of two or more parallel struts between the joints, each strut in the group having a width less than 0.4 mm.

[0051] In some applications, when the frame is in the unconstrained configuration, the groups of struts are arranged such that adjacent long edges of each of the struts are within 1 mm of each other.

[0052] According to some applications of the present invention, there is also provided a method for treating a subject having a diseased mitral valve, the method comprising:

[0053] inserting a docking element into a left atrium of a subject, the docking element comprising a ring, a frame extending from the ring, and a radial protrusion configured to extend radially outward from the frame;

[0054] The docking element is deployed within the left atrium of the subject such that:

[0055] No portion of the docking element extends through the subject's mitral valve,

[0056] The radial protrusion is disposed adjacent to a native mitral valve annulus of the subject such that tissue ingrowth from a wall of the left atrium to the radial protrusion occurs at least adjacent to the native mitral valve annulus of the subject,

[0057] The frame anchors the docking element within the left atrium by expanding the frame against the wall of the left atrium and the roof of the left atrium before tissue ingrowth to the point of radial protrusion occurs, and

[0058] providing a bridging material between the radial protrusion and the ring, the bridging material being configured to form a seal between the radial protrusion and the ring; and

[0059] After the ingrowth of tissue from the wall of the left atrium into the radial protuberance occurs:

[0060] inserting a prosthetic mitral valve device into the interior of the annulus; and

[0061] The prosthetic mitral valve device is radially expanded against the annulus such that the prosthetic mitral valve device is anchored within the annulus.

[0062] According to some applications of the present invention, there is also provided an apparatus for treating a subject having a diseased mitral valve, the apparatus comprising:

[0063] A docking element configured to be implanted within the left atrium of a subject such that no portion of the docking element extends through a mitral valve of the subject, the docking element configured to produce tissue ingrowth from a wall of the left atrium to the docking element at least proximate a native mitral valve annulus of the subject, and the docking element comprising:

[0064] ring;

[0065] a frame extending upwardly from the annulus, the frame being configured to anchor the docking element within the left atrium by expansion of the frame against at least one of a wall of the left atrium and a roof of the left atrium before tissue ingrowth into the docking element occurs,

[0066] The frame includes stays connected to each other at joints so as to define a cell, and at least some of the stays are shaped to define undulating and / or zigzag regions near the joints; and

[0067] A prosthetic mitral valve device, the prosthetic mitral valve device being configured to:

[0068] being at least partially positioned within the docking element after tissue ingrowth from the wall of the left atrium into the docking element has occurred, and

[0069] Becoming anchored to the docking element at least in part by expanding radially against the ring.

[0070] In some applications, by being formed to define undulating and / or zigzag regions, the effective strut length of the struts is elongated near the joint so that strains occurring near the joint will be spread over a greater effective length than if the struts were not formed to define undulating and / or zigzag regions.

[0071] According to some applications of the present invention, there is also provided an apparatus for treating a subject having a diseased mitral valve, the apparatus comprising:

[0072] A docking element configured to be implanted within the left atrium of a subject such that no portion of the docking element extends through a mitral valve of the subject, the docking element configured to produce tissue ingrowth from a wall of the left atrium to the docking element at least proximate a native mitral valve annulus of the subject, and the docking element comprising:

[0073] ring;

[0074] a frame extending upwardly from the annulus, the frame being configured to anchor the docking element within the left atrium by expansion of the frame against at least one of a wall of the left atrium and a roof of the left atrium before tissue ingrowth into the docking element occurs,

[0075] The frame comprises struts connected to each other at joints so as to define a grid, at least some of the struts being arranged to define groups of two or more parallel struts between the joints, each strut in the group having a width of less than 0.4 mm; and

[0076] A prosthetic mitral valve device configured to:

[0077] being at least partially positioned within the docking element after tissue ingrowth from the wall of the left atrium into the docking element has occurred, and

[0078] Becoming anchored to the docking element at least in part by expanding radially against the ring.

[0079] In some applications, when the frame is in the unconstrained configuration, the groups of struts are arranged such that adjacent long edges of each of the struts are within 1 mm of each other.

[0080] The present invention will be more fully understood from the following detailed description of embodiments of the present invention in conjunction with the accompanying drawings, in which: BRIEF DESCRIPTION OF THE DRAWINGS

[0082] Figure 1A , Figure 1B and Figure 1C is a schematic diagram of a docking element configured to facilitate anchoring a prosthetic mitral valve device to a mitral valve of a subject according to some applications of the present invention;

[0083] Figure 2A and Figure 2B is a schematic diagram of a framework of a docking element according to some applications of the present invention, the docking element including stays shaped to have springy, undulating and / or zigzag zones;

[0084] Figure 3 is a schematic diagram of a framework of a docking element according to some applications of the present invention, the docking element comprising stays arranged in parallel stay pairs; and

[0085] Figure 4A and Figure 4B is a schematic diagram of the fabric of the radial protrusions of the docking element and / or the fabric of the skirt of the docking element according to some applications of the present invention. DETAILED DESCRIPTION

[0086] Reference now Figure 1A, Figure 1B and Figure 1C , which are schematic diagrams of a docking element 20 according to some applications of the present invention. Figure 1A shows a side view of the docking element, and Figure 1B Shows relative to Figure 1A The view shown is a view of the docking element rotated 90 degrees about the longitudinal axis 22 of the frame 24 of the docking element. The docking element is generally configured to facilitate the attachment of a prosthetic mitral valve device 28 ( Figure 1A ) is anchored to the mitral valve of the subject. Figure 1C The docking element is shown deployed inside the left atrium 26 of a subject before a prosthetic mitral valve device is placed inside the docking element. As shown, in this state, the native mitral valve leaflet 30 is still in place. The docking element is disposed in its entirety within the left atrium 26 and does not extend into the left ventricle 31.

[0087] Typically, the prosthetic mitral valve device is a stent valve that includes a stent frame 32 configured to support a prosthetic valve leaflet 34. Typically, the stent frame is covered with a material 33 (e.g., a fabric such as PET, PTFE and / or nylon). The prosthetic mitral valve device is typically implanted within the natural mitral valve of a subject with a diseased natural valve, and the prosthetic valve leaflets function to replace the function of the natural valve leaflets. Typically, the prosthetic valve leaflets are configured to act as a one-way valve, whereby in their open position relative to each other, the leaflets allow flow from the inlet (on the atrial side) through the prosthetic valve device to the outlet (on the ventricular side), and reverse flow is prevented because the collapsible, slack portion of the valve leaflets contracts inwardly to block reverse flow.

[0088] Typically, the docking element 20 is implanted in the left atrium more than one week or more than one month prior to implanting the prosthetic mitral valve device. After implantation of the docking element and before implantation of the prosthetic mitral valve device, the anchoring of the docking element is typically enhanced by tissue ingrowth occurring around the docking element, such as described below. Typically, no portion of the docking element extends through the subject's native mitral valve. Furthermore, typically, due to the fact that no portion of the docking element extends through the subject's native mitral valve, the native mitral valve leaflets are able to continue to function in their normal manner after implantation of the docking element and before implantation of the prosthetic mitral valve device.

[0089] For some applications, the docking element includes a frame 24 and a ring 40 coupled to the frame. Ring 40 is described in further detail below. Typically, with the ring in its deployed state inside the left atrium, the ring is disposed transversely relative to the frame such that a plane defined by the ring is substantially parallel to the longitudinal axis of the frame.

[0090] For some applications, the docking element is placed into left atrium 26 via atrial septum 42 by advancing the docking element in a lateral direction relative to the left atrium of the subject along its longitudinal axis (eg, Figure 1C ). Subsequently, without substantially rotating the longitudinal axis of the docking element, the docking element is deployed within the left atrium of the subject such that the ring 40 is disposed proximate to (e.g., at the mitral annulus, and / or slightly above (e.g., as described above)) the mitral valve annulus 44 and is disposed transversely relative to the frame. (Note that in some cases, the frame may be rotated about the longitudinal axis, and / or the longitudinal axis itself may be rotated a small amount in order to align the ring with the native mitral valve annulus.) Thus, even in the deployed state of the docking element, the longitudinal axis of the frame is substantially parallel to the plane defined by the mitral valve annulus of the subject. By deploying the docking element in this manner, the longitudinal axis of the docking element does not need to be significantly rotated relative to the left atrium between transseptal insertion into the left atrium and deployment within the left atrium. In contrast, if the ring is disposed at a longitudinal end of the frame such that the plane defined by the ring is substantially perpendicular to the longitudinal axis of the frame, this would make transseptal insertion of the docking element challenging. This is because the longitudinal axis of the docking element would need to be rotated within the relatively small volume defined by the left atrium (approximately 90 degrees relative to the atrial septum) and released from the delivery device.

[0091] For some applications, the ring is configured to be disposed at a level with, slightly above, or slightly below the height of the mitral valve annulus, and the outer perimeter of the ring is smaller than the perimeter defined by the mitral valve annulus, so that the ring "floats" above the native valve leaflets. These applications of the present invention will be described in further detail below.

[0092] Typically, the frame 24 is made of a self-expandable shape memory material (e.g., a shape memory alloy such as Nitinol), and the frame 24 is cut and shaped to define more than one cell 45 defined by struts 46 of the shape memory material. Alternatively or additionally, the frame is assembled from a wire made of a self-expandable shape memory material (e.g., a shape memory alloy such as Nitinol). Typically, the portion of the frame closest to the ring is covered by a skirt 48 of a material that facilitates tissue ingrowth into the frame. For example, the skirt can be made of a fabric (such as PET, PTFE and / or nylon) and can be coupled to the exterior of the frame and / or the ring using sutures. Typically, a portion of the frame configured to be disposed near the mitral annulus (e.g., at the mitral annulus and / or slightly above the mitral annulus (e.g., within 15 mm of the mitral annulus)) is covered by the skirt. For some applications, the skirt is configured to be disposed from between 1 mm and 2 mm above the mitral annulus (from the height of the mitral annulus) to a height between 15 mm and 20 mm above the mitral annulus. For some applications, a tissue ingrowth element is coupled to the skirt to promote tissue ingrowth. Figure 4BAs described. For example, such tissue ingrowth elements may include hooks or loops (e.g., similar to those used in hook and loop fasteners), barbs, clips, pins, etc. For some applications, the skirt extends from the loop to at least 5 mm (e.g., at least 10 mm) and / or less than 25 mm (e.g., less than 20 mm) above the frame, such as a height H1 between 5 mm and 25 mm, or between 10 mm and 20 mm. For some applications (not shown), from where the skirt terminates (i.e., from the upper end of the skirt), the struts of the frame are covered in a sleeve of material that is typically the same material from which the skirt 48 is made. The sleeve of material is configured to encourage tissue ingrowth into the struts of the frame. Typically, the sleeves are sutured together at the joints between the struts. For some applications, the docking element is deployed in the left atrium so that the frame 24 extends to the top of the left atrium (e.g., Figure 1C shown).

[0093] For some applications, the docking element includes a radial protrusion 50 that extends radially from the frame, typically above and / or flush with the ring 40. For example, the radial protrusion can be shaped as a folded edge and / or annular convexity arranged around the circumference of the frame. For some applications, the radial protrusion is configured to conform to the shape of the wall of the left atrium near the mitral valve ring so that the radial protrusion fills any gap between the wall of the left atrium near the mitral valve ring and the outside of the frame. Typically, the radial protrusion is configured to contact the inner wall of the left atrium and promote tissue to grow inward from the inner wall of the left atrium to the protrusion. Therefore, due to tissue inward growth, the docking element typically becomes anchored to the inner wall of the left atrium. For some applications, the protrusion is configured to act as a bridge for tissue inward growth, wherein the protrusion is configured to promote tissue to grow inward from the inner wall of the left atrium, across the protrusion and into the skirt 48 and / or into the frame 24. Typically, the protrusion is configured to contact the inner wall of the left atrium near the mitral annulus, for example, at the height of the mitral annulus, and / or at a height from between 1 mm and 2 mm above the mitral annulus up to between 15 mm and 20 mm above the mitral annulus.

[0094] Typically, the outer perimeter of the ring is smaller than the size of the inner perimeter of the radial protrusion 50. Further typically, there is a bridging material 56 (e.g., fabric) that bridges between the ring and the radial protrusion and forms a seal between the ring and the radial protrusion. Typically, the bridging material 56 that bridges between the ring and the radial protrusion is part of the skirt 48. In accordance with the above description, for some applications, the docking element includes a combination of the following three components: 1) a protrusion 50 that is configured to anchor to tissue near the mitral valve annulus via tissue ingrowth, 2) a ring 40 to which the prosthetic mitral valve device is configured to anchor, and 3) a bridging material 56 that bridges between the two elements and forms a seal between the two elements. For some applications, the protrusion 50 protrudes directly from the outside of the ring 40. For some applications, the protrusion is elliptical in shape, and a first portion of the protrusion (e.g., the side of the ellipse surrounding the minor axis) protrudes directly from ring 40 and a second portion of the protrusion (e.g., the side of the ellipse surrounding the major axis) is coupled to the ring via bridging material 56.

[0095] For some applications, radial protrusion 50 is self-expandable and includes a coil spring 52 (which is typically made of a self-expandable metal or alloy, such as Nitinol) covered with a fabric 54 (e.g., PET, PTFE and / or nylon) that is configured to promote tissue ingrowth. According to various embodiments, coil spring 52 is a rounded spiral, a triangular spiral, or a spiral of a different shape. The coil spring is configured to extend the self-expanding protrusion radially outward from the outer surface of the frame so that the protrusion conforms to the anatomical structure of the left atrium in areas where the frame itself is not flexible enough. In this way, the self-expanding protrusion fills the gap between the outer surface of the frame and the inner wall of the left atrium.

[0096] For some applications, radial protrusion 50 is used with other devices configured to be placed within a chamber of a subject's heart (e.g., a mitral annulus repair device, e.g., as described in US 2020 / 0093599 to Benichou, which is incorporated herein by reference), mutatis mutandis.

[0097] For some applications, radial protrusion 50 comprises a material filled with a substance (e.g., a hydrogel) that is configured to expand upon contact with blood. For some applications, the protrusion is not self-expanding, but is an expandable protrusion. For example, the protrusion may include an expandable ring convexity expanded with an expandable substance (e.g., an epoxy resin material). For some applications, the protrusion is configured as a brush strip. Alternatively or additionally, the protrusion is generally similar to Figures 1A-1C, but excluding spring 52, a wire (e.g., configured in a ring or zigzag configuration) extends radially outward from the frame and is configured to support fabric 54 so that the fabric extends approximately perpendicularly from the outer surface of the frame. Typically, radial protrusions 50 extend radially outward from the outer surface of frame 24 around more than 70% (e.g., more than 90%) of the circumference of the frame. In addition, typically, protrusions 50 extend radially outward from the outer surface of frame 24 around the entire circumference of the frame. For some applications, the radial protrusions are provided on the frame at a height flush with ring 40. Optionally or additionally, the protrusions protrude from the frame at a height between 1 mm and 20 mm (e.g., between 2 mm and 15 mm) above the ring.

[0098] As described above, typically, docking element 20 is configured to help anchor prosthetic mitral valve device 28 to the mitral valve of the subject. The docking element typically includes (a) a ring 40 (within which the prosthetic valve device is anchored), and (b) a portion of a frame covered by a skirt 48 to promote tissue in-growth from the atrial wall near the mitral valve annulus (e.g., at or slightly above the height of the mitral valve annulus (e.g., within 15 mm of height)). The portion of the frame covered by skirt 48 is typically configured to be sized to conform to the size of the left atrium when the docking element is in a deployed configuration. Typically, the size of the ring (e.g., the outer perimeter of the ring) is smaller than this portion of the frame. Further typically, a portion of skirt 48 bridges and seals between the ring and this portion of the frame. In this way, for some applications, the docking element occupies and seals some areas defined by the natural mitral valve annulus. Therefore, the ring acts as an artificial mitral valve annulus that is smaller than the natural mitral valve annulus. Typically, the inner diameter of the ring 40 is greater than 20 mm. For some applications, the inner diameter of the ring 40 is smaller than the inner diameter of the native mitral valve annulus 44. For example, the inner diameter of the ring 40 can be less than 30 mm, such as less than 28 mm.

[0099] For some applications, the docking element includes frame 24, ring 40, skirt 48, and radial protrusions 50. The radial protrusions are configured to extend to the wall of the left atrium near (e.g., at or slightly above the height of the native mitral valve annulus (e.g., within 15 mm of the height) thereof, and to promote tissue in-growth from the left atrium of the subject to the docking element, e.g., tissue in-growth to the radial protrusions themselves, and / or tissue in-growth to the frame and / or skirt via the radial protrusions. A portion of skirt 48 serves as a bridging material 56 and bridges and seals between the radial protrusions and the ring, such that the bridging material occupies and seals a portion of the area defined by the native mitral valve annulus. Thus, the ring acts as an artificial mitral valve annulus that is smaller than the native mitral valve annulus.

[0100] In accordance with the above, for some applications, the size of the prosthetic mitral valve is smaller than the size of the native mitral valve. For example, the prosthetic valve leaflets 34 of the prosthetic mitral valve device can span a diameter that is smaller than the diameter of the measured native mitral valve annulus (the diameter of the native mitral valve annulus is typically measured using a mitral valve measurement ring and / or using an imaging method, such as ultrasound). Alternatively, because the native mitral valve annulus is typically elliptical, the maximum diameter spanned by the leaflets can be smaller than the major axis of the ellipse defined by the native mitral valve annulus.

[0101] For some applications, one or more advantages of a prosthetic valve sized in this manner, relative to a larger prosthetic valve, may include: the prosthetic valve device having a lower crimp profile (and thus using a delivery device having a smaller diameter), less foreign material inside the subject's heart, less force exerted on the prosthetic valve leaflets (and thus improved durability), better anchoring of the prosthetic valve device, less interference with native anatomy, and / or better maintenance of left ventricular outflow tract patency. Generally, sizing the leaflets smaller allows the prosthetic mitral valve device to have a shorter frame, thereby reducing obstruction of the left ventricular outflow tract (other things being equal). Alternatively or additionally, a prosthetic mitral valve device having prosthetic valve leaflets that span a diameter that is smaller than the diameter of the native mitral valve annulus may be used for various reasons.

[0102] refer to Figure 1B , the frame typically defines a pore 51, which is configured to be disposed on a side of the frame positioned near the mitral valve annulus. For some applications, the pore 51 defines an open area greater than 3.0 square centimeters (e.g., greater than 4.0 square centimeters) and / or less than 6.0 square centimeters (e.g., less than 5.5 square centimeters), such as 3.0-6.0 square centimeters (or 4.0-5.5 square centimeters). Typically, the ring 40 is disposed within the pore 51. In addition, typically, the skirt 48 covers any space between the struts defining the pore 51 and the ring 40 so as to seal the space. For some applications, the skirt additionally covers the space (or portion thereof) defined by another pore. Typically, the ring is connected to the struts defining the pore 51 via the skirt 48. For example, the skirt 48 can be sutured to both the struts defining the pore 51 and the ring 40. For some applications, the ring 40 is directly connected to the struts defining the pore 51 (not shown). For some applications, a portion of skirt 48 also serves as a bridging material 56 , bridging between ring 40 and radial protrusion 50 .

[0103] Typically, before tissue ingrowth occurs, the docking element is anchored in place in the left atrium by expanding the framework so as to contact the wall and top of the left atrium. For some applications, the framework is configured to apply relatively low pressure only to the inner wall of the left atrium so that the framework conforms to the shape of the left atrium without forcing the atrium to deform. For some applications, in this way, the framework allows the natural compliance of the inner wall of the left atrium to be maintained substantially. For example, the framework can be configured so that a force of 1N is required to reduce the diameter of the framework by 10mm. For some applications, each lattice 45 of the framework defines an open area greater than 3.0 square centimeters (e.g., greater than 4.0 square centimeters) and / or less than 6.0 square centimeters (e.g., less than 5.5 square centimeters), for example 3.0-6.0 square centimeters (or 4.0-5.5 square centimeters). For some applications, the lattice is configured so that the open portion of the lattice is arranged at the junction of the pulmonary vein and the left atrium. Typically, the skirt 48 does not extend to the height of the junction of the pulmonary vein and the left atrium on the framework. In this way, the frame does not interfere with blood flow from the pulmonary veins to the left atrium. It should be noted that the frame 24 is generally configured so that the contact between the frame and the left atrium is substantially evenly distributed over the wall of the left atrium and the top of the left atrium. It should also be noted that, generally, the frame does not include any additional anchoring portions for anchoring to body parts other than the wall and top of the left atrium (such as the left atrial appendage and / or the pulmonary veins).

[0104] Typically, docking element 20 is anchored to the heart of the subject by: (a) tissue ingrowth into the portion of the frame that is disposed proximal to the mitral annulus (e.g., at and / or slightly above the mitral annulus (e.g., as described above)) and covered by skirt 48, (b) tissue ingrowth from the wall of the left atrium to struts 46 of the frame, (c) tissue ingrowth into radial protrusions 50, and / or (d) tissue ingrowth into the frame and / or skirt via radial protrusions. Typically, before tissue ingrowth occurs, the docking element is anchored in place within the left atrium by expansion of the frame so as to contact the wall and roof of the left atrium.

[0105] Typically, the docking element is configured so that when the prosthetic mitral valve device is implanted, the anchoring of the docking element in the left atrium is mainly carried out via tissue ingrowth to the docking element. Typically, the mitral valve annulus can withstand higher loads than other parts of the wall of the left atrium. Therefore, for some applications, the docking element is configured so that when the prosthetic mitral valve device is implanted, the anchoring of the docking element in the left atrium is mainly carried out via tissue ingrowth from the atrial wall near the mitral valve annulus (e.g., at its height or slightly higher (e.g., within 15mm of the height)) to the docking element. For example, since the docking element includes a skirt 48 (the skirt 48 is configured to be disposed near the mitral valve annulus), the docking element can be configured to promote greater ingrowth near the mitral valve annulus than at other parts of the frame. Optionally or additionally, by including a docking element with a radial protrusion 50 (the radial protrusion 50 is configured to be disposed near the mitral valve annulus), the docking element is configured to promote greater tissue ingrowth near the mitral valve annulus than at other parts of the frame.

[0106] The two-stage implantation procedure described above is similar to a valve-in-valve procedure to a certain extent, through which a new prosthetic valve is implanted inside a previously implanted prosthetic valve. The previously implanted prosthetic valve is usually initially anchored to the natural mitral valve via suture, but then becomes anchored due to tissue ingrowth to the prosthetic valve. In such a case, the new valve usually becomes anchored in the previously implanted valve, and due to tissue ingrowth relative to the previously implanted valve and mechanical forces applied to the heart by the previously implanted prosthetic valve, the previously implanted valve is firmly anchored to the natural mitral valve. Similarly, according to some applications of the present invention, initially, docking element 20 is implanted and due to tissue ingrowth relative to docking element and mechanical forces applied to the heart by docking element, docking element 20 is allowed to become anchored to the heart of the subject. Subsequently, once the docking element is anchored in the heart of the subject, the prosthetic mitral valve device is anchored to the docking element (and usually anchored to the ring 40 of the docking element). For some applications, stent frame 32 of prosthetic mitral valve device 28 has an hourglass-shaped outer profile that is configured to facilitate anchoring of the frame to annulus 40 of docking element 20 .

[0107] According to the corresponding applications of the present invention, the docking element 20 and / or the prosthetic mitral valve device 28 are delivered to the heart of the subject transapically, transseptally and / or transaortically via the femoral vein. For some applications, by delivering the docking element 20 and the prosthetic mitral valve device 28 in separate delivery steps, the size of the delivery device used to deliver the docking element 20 and the prosthetic mitral valve device 28 can be smaller than when the prosthetic mitral valve device is delivered together with the docking element (other conditions remain unchanged). For some applications, reducing the size of the required delivery device in the manner described above facilitates transseptal insertion of the docking element and / or the prosthetic mitral valve device.

[0108] For some applications, the docking element 20 and the prosthetic mitral valve device 28 are implanted above the natural mitral valve in the same procedure as each other, and the docking element is usually implanted before the prosthetic mitral valve device. For some such applications, when the prosthetic mitral valve device is initially implanted, the prosthetic mitral valve leaflet 34 is kept open, for example, using sutures. Typically, the prosthetic mitral valve leaflet maintains an open state (e.g., using sutures) for a period of more than one week or more than one month, during which the docking element becomes anchored to the subject's heart by tissue ingrowth according to the technology described above. In this way, during the time period when the docking element becomes anchored to the subject's heart by tissue ingrowth, the docking element does not need to withstand the blood load that impacts the prosthetic valve leaflet. Subsequently, the element (e.g., suture) that keeps the prosthetic valve leaflet open is removed, allowing the prosthetic valve leaflet to begin to function.

[0109] Now refer to Figure 2A and Figure 2B , which are schematic diagrams of a frame 24 of a docking element 20, which, according to some applications of the present invention, includes struts 46 that are shaped to have elastic, undulating and / or zigzag regions 70. Figure 2A is a schematic diagram of the frame 24 in its non-radially constrained configuration and without the remainder of the docking element. Figure 2B is a schematic diagram of a flattened outline of a frame, depicting what the frame would appear like if (for purposes of illustration) it were cut longitudinally along its length at given perimeter locations prior to shaping the frame and then laid flat on a surface. Figure 2A-2B The illustrated frame 24 is generally similar to the frame 24 described above (e.g., with reference to Figures 1A-1C ), except for the following differences.

[0110] As described above, the frame 24 is typically configured to conform to the shape of the atrial wall and top. Therefore, during the subject's cardiac cycle, the frame will generally expand and contract. As the frame expands and contracts, the angles between the struts 46 of the frame change. Typically, most of the stress and strain to which the struts are subjected occurs at the junctions between the struts as the angles between the struts change. As shown in FIGS. 2A-2B , for some applications, the struts are formed to have elastic, undulating, and / or zigzag regions 70 near the junctions 72 between the struts 46 of the frame 24. For example, the elastic, undulating, and / or zigzag regions may be between 1 mm and 20 mm (e.g., between 2 mm and 15 mm) within the junction (as measured along the longitudinal axis of the straight portion of the strut). In this way, the effective strut length is elongated near the junction, which spreads the stress and strain occurring near the junction over a larger effective length. (Note that in Figure 2A ) Each region marked by a dashed circle with the letter A next to it typically includes an undulating and / or zigzag bracing region, but only one such region is depicted for illustrative purposes.

[0111] Reference now Figure 3 , which is a schematic diagram of a frame 24 of a docking element 20, which, according to some applications of the present invention, includes struts 46 arranged in parallel strut pairs. Figure 3 A schematic diagram illustrating the flattened profile of frame 24 is depicted, which depicts what the frame would appear like if (for illustrative purposes) it were cut longitudinally along its length at given perimeter locations before the frame was shaped and then laid flat on a surface. Figure 3 The illustrated frame 24 is generally similar to the frame 24 described above (e.g., with reference to Figures 1A-1C ), except for the following differences.

[0112] like Figure 3As shown, for some applications, the stays are relatively thin to reduce the strain caused by bending of the stays. For example, the stays can have a width of less than 0.4mm, such as a width of less than 0.3mm. Relatively thin stays can cause the stays to have relatively low stiffness. Therefore, for some applications, in at least a portion of the frame 24, the stays are arranged in parallel stay pairs 74 to provide greater rigidity for the stays. Typically, when the frame is set in a non-constrained configuration, the stay pairs 74 are arranged so that the adjacent long edges of each of the stays are within 1mm from each other (for example, within 0.6mm from each other). For some applications, more than two stays (i.e., three or more stays) are arranged parallel to each other. Typically, parallel stays extend from a single joint 72 and are located in the same plane with each other and in the same plane with the joint, so that the stays are configured not to rotate relative to each other. For some applications (not shown), each individual stay in this pair is in the form of a cable and / or a coil spring. For some applications, individual struts of frame 24 (i.e., struts that are not arranged parallel to other struts (e.g., Figures 1A-1C The struts of the frame 24 shown in any one of Figures 2A-2B are in the form of cables and / or coil springs.

[0113] Reference now Figure 4A , which is a schematic diagram of the fabric 54 of the radial protrusion 50 and / or the fabric of the skirt 48 according to some applications of the present invention, the fabric is braided. For some applications, the braided fabric is composed of a combination of elastic wire 60 (made of metal or alloy (such as Nitinol)) and polymer material 62 (such as PET, PTFE and / or nylon). Typically, the density and direction of each material within the braid is such that the fabric has the desired properties of the portion of the docking element using the fabric.

[0114] Reference now Figure 4B, which is a schematic diagram of the fabric 54 of the radial protrusion 50 and / or the fabric of the skirt 48 according to some applications of the present invention. For some applications, the tissue ingrowth element 64 is connected to the fabric layer to promote tissue ingrowth. For example, such a tissue ingrowth element may include a hook or loop (e.g., similar to those used in hook and loop fasteners), a barb, a clip, a pin, etc. The tissue ingrowth element is configured to contact the wall of the left atrium and promote tissue growth into the fabric of the fabric layer. For some applications, the tissue ingrowth element includes a fabric sheet, and fibers (e.g., hook-shaped fibers, as shown) are connected to the fabric sheet in a vertical arrangement relative to the fabric sheet. For some applications, the fibers are directly connected to the fabric 54 of the radial protrusion 50 and / or the fabric of the skirt 48. The fibers are configured to contact the wall of the left atrium and promote tissue growth into the fibers and fabric sheet. For some applications, the tissue ingrowth element defines a 3D structure (e.g., as described above) that is configured to increase the contact area between the tissue and the frame and serve as a support frame for tissue growth therein.

[0115] For some applications, a portion of the docking element is biodegradable. For example, at least a portion of the frame 24 can be biodegradable. Typically, even for such applications, the skirt 48, the ring 40 and / or the radial projection 50 are not biodegradable. For some such applications, after a given period of time (by which time the tissue has grown inward), the frame biodegrades, leaving only the ring 40, the skirt 48 and / or the projection 50 in place. Optionally or additionally, the skirt 48 and / or the radial projection 50 are sutured to the frame by biodegradable sutures. Typically, after tissue in-growth occurs relative to the skirt and / or the radial projection, the suture biodegrades and the frame is removed from the left atrium of the subject. In some such applications, the frame is covered with a coating that prevents tissue growth so that tissue does not grow inward relative to the frame, and the frame can be easily removed.

[0116] For some applications, the docking element includes a left atrial appendage anchor, for example, as described in WO 18 / 178966, which is incorporated herein by reference. Optionally or additionally, the docking element includes a left atrial appendage closure portion, which is configured to close the mouth of the left atrial appendage. For some applications, the docking element includes an anchor and / or a closure portion, which is configured to anchor to or close the fossa ovalis.

[0117] For some applications, the devices and methods described herein are performed mutatis mutandis for the tricuspid valve and / or a different valve in a subject.

[0118] For some applications, the apparatus and methods described herein are performed in conjunction with the apparatus and methods described in the following patent applications:

[0119] US 16 / 498,065 to Benichou et al., entitled “Docking elements,” which is the U.S. national phase of International Patent Application No. PCT / IL2018 / 050229, filed on March 1, 2018, by Benichou et al., entitled “Docking elements,” published as WO 18 / 178966, which claims priority to U.S. Provisional Application No. 62 / 476,989, filed on March 27, 2017, by Benichou, entitled “Docking elements”; and / or

[0120] US 2020 / 0093599, filed on September 24, 2019 by Benichou et al., entitled “Docking elements,” claims priority to U.S. Provisional Application 62 / 735,866, filed on September 25, 2018 by Benichou et al., entitled “Docking elements.”

[0121] All of the above-cited applications are incorporated herein by reference.

[0122] Those skilled in the art will appreciate that the present invention is not limited to what has been particularly shown and described hereinabove. Rather, the scope of the present invention includes combinations and sub-combinations of the various features described hereinabove, as well as variations and modifications of the present invention that would occur to those skilled in the art after reading the foregoing description and that are not in the prior art.

Claims

1. An apparatus for treating a subject having a diseased mitral valve, the apparatus comprising: A docking element configured to be implanted within a left atrium of the subject such that no portion of the docking element extends through a mitral valve of the subject, the docking element comprising: ring; a frame extending upwardly from the ring, the frame configured to anchor the docking element within the left atrium by expansion of the frame against at least one of a wall of the left atrium and a roof of the left atrium before tissue ingrowth into the docking element occurs; a radial protrusion configured to extend radially outward from the frame to be disposed adjacent to a native mitral valve annulus of a subject and to produce tissue ingrowth from a wall of the left atrium to the radial protrusion at least adjacent to the native mitral valve annulus of the subject; and a bridging material disposed between the radial protrusion and the ring, the bridging material forming a seal between the radial protrusion and the ring; and A prosthetic mitral valve device, the prosthetic mitral valve device being configured to: After ingrowth from the wall of the left atrium to the radial protrusion occurs, at least partially disposed within the interior of the docking element, and Becoming anchored to the docking element at least in part by expanding radially against the ring.

2. The device according to claim 1, wherein: The radial protrusion is configured to extend radially outward from the frame at a level flush with the ring.

3. The device according to claim 1, wherein: The radial protrusions are configured to extend radially outwardly from the frame at a height between 1 mm and 20 mm above the ring.

4. The device according to claim 1, wherein: The radial protrusions are configured to conform to the shape of a wall of the left atrium near the mitral valve annulus such that the radial protrusions fill any gaps between an exterior of the frame and the wall of the left atrium near the mitral valve annulus.

5. The device according to claim 1, wherein: The annulus is sized smaller than the subject's native mitral valve annulus.

6. The device according to claim 1, wherein: The radial projections are configured to generate tissue ingrowth from a wall of the left atrium toward the frame onto the radial projections at least proximate a native mitral valve annulus of the subject.

7. The device according to claim 1, wherein: The radial protrusion comprises a flange.

8. The device according to claim 1, wherein: The radial protrusion comprises an annular convex radial protrusion.

9. The device according to claim 1, wherein: The radial protrusion has an elliptical shape.

10. The device according to claim 1, wherein: The radial protrusion is configured to extend radially outward from the frame around more than 70% of the circumference of the frame.

11. The device according to any one of claims 1 to 10, wherein: The docking element further comprises a skirt covering a portion of the frame extending from the ring to a height of at least 5 mm on the frame from the ring, and wherein the bridging material comprises a portion of the skirt.

12. The device according to claim 11, wherein The radial projections are configured to generate tissue ingrowth into the radial projections from a wall of the left atrium toward the skirt at least proximate a native mitral valve annulus of the subject.

13. The device according to any one of claims 1 to 10, wherein: The radial protrusions are configured to be self-expanding.

14. The device according to claim 13, wherein: The radial protrusion comprises a spiral member covered with a covering material.

15. The device according to any one of claims 1 to 10, wherein: The frame comprises struts connected to each other at joints so as to define a cell, and wherein, near the joints, at least some of the struts are shaped to define undulating and / or zigzag regions.

16. The device according to claim 15, wherein: By being shaped to define undulating and / or zigzag regions, the effective strut length of the struts is elongated near the joints, so that strains that would occur near the joints are spread over a greater effective length than if the struts were not shaped to define undulating and / or zigzag regions.

17. The apparatus according to any one of claims 1 to 10, wherein: The frame comprises struts connected to each other at joints to define a grid, and wherein at least some of the struts are arranged to define groups of two or more parallel struts between the joints, each strut in the group having a width of less than 0.4 mm.

18. The apparatus according to claim 17, wherein: When the frame is in the unrestrained configuration, the groups of struts are arranged such that adjacent long edges of each of the struts are within 1 mm of each other.

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