Implantable device for treating mitral valve regurgitation

Abstract

An implantable device for treating mitral valve regurgitation, the device being configured to expand from a compressed state into an expanded state. The device comprises a stent element consisting of (i) an atrial anchoring stent-portion, and (ii) a valve-carrying stent-portion being fixedly connected with one another, and a valve-element. The atrial anchoring stent-portion has a balloon-like shape and the valve-carrying stent-portion has a cylindrical shape, such, that the valve-carrying stent-portion is positioned intra-annular without contacting the annulus of a native mitral valve.

Claims

1. Implantable device for treating mitral valve regurgitation, the device being configured to expand from a compressed state into an expanded state, and comprising: a stent element comprising an atrial anchoring stent-portion, and a valve-carrying stent-portion, the atrial anchoring stent-portion being fixedly connected with the valve-carrying stent-portion, wherein the atrial anchoring portion, in the expanded state of the device, has a balloon-like shape and is so dimensioned as to have a diameter which is larger than a diameter of an annulus of a native mitral valve present between an atrium and a ventricle of a heart to be treated, and is so dimensioned and configured to anchor the device via radial force in an atrium of a heart to be treated when the device is in the expanded state, wherein the valve-carrying stent-portion, in the expanded state of the device, has a substantially cylindrical shape with a diameter (d3) which, in the expanded state, is so dimensioned as to be smaller than a diameter of an annulus of a native mitral valve of a heart to be treated, such that there is no contact between the annulus of the native mitral valve and the valve-carrying stent-portion; and a valve element comprising a skirt-portion and a valve-portion, the skirt-portion being externally mounted to the valve-carrying stent-portion, and the valve-portion being internally mounted to the valve-carrying stent-portion.

2. The device of claim 1, wherein, when implanted, the valve-element is so dimensioned and configured such that the native mitral valve's function is supported without replacing or impairing the native mitral valve's function.

3. The device of claim 1, wherein the atrial anchoring stent-portion and the valve-carrying stent-portion are integrally formed.

4. The device of claim 1, wherein the atrial anchoring stent-portion is configured to be anchorable in an atrium of a heart.

5. The device of claim 1, wherein the skirt-portion and the valve-portion of the valve element are made of a same material.

6. The device of claim 5, wherein the skirt-portion and the valve-portion of the valve element are made of pericardium.

7. The device of claim 1, wherein the valve element is a bi- or tri-leaflet valve.

8. The device of claim 1, wherein the stent-element is made of a shape-memory material.

9. The device of claim 8, wherein the stent-element is a laser-cut stent-element and/or composed of wires.

10. The device of claim 8, wherein the atrial anchoring stent-portion and/or the valve-carrying stent-portion is made from braided or otherwise intersected wires.

11. The device of claim 8, wherein the atrial anchoring stent-portion and/or the valve-carrying stent-portion is made from wire-loops.

12. The device of claim 8, wherein the stent-element is made of ninitol.

13. The device of claim 1, wherein the substantially cylindrical shape of the valve-carrying stent-portion, in the expanded state of the device, has a substantially continuous diameter (d3) along its cylindrical length (l).

14. Method for treating mitral valve regurgitation, the method comprising the step of deploying the device as claimed in claim 1 in a heart of a patient in need of being treated.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The aforementioned features and the features still to be explained below are shown in the figures, in which:

(2) FIG. 1 shows a schematic drawing of a human heart;

(3) FIG. 2 shows a schematic drawing of an exemplary embodiment of the device placed in the correct position in the left atrium of a heart; and

(4) FIGS. 3A-3D are schematic drawings of various exemplary embodiments of the device displaying various designs.

DESCRIPTION OF PREFERRED EMBODIMENTS

(5) In FIG. 1, a human heart 50 is depicted, having a right atrium 54, a right ventricle 55, a left atrium 56 and a left ventricle 57. Also depicted in FIG. 1 is a portion of the vena cava superior 52, entering the heart 50 via the right atrium 54, and a portion of the vena cava inferior 53.

(6) In more detail, the superior vena cava 52 returns the blood from the upper half of the body, and opens into the upper and back part of the right atrium 54, the direction of its orifice 52a being downward and forward. Its orifice 52a has no valve.

(7) The inferior vena cava 53, which has a larger diameter than the superior vena cava 52, returns the blood from the lower half of the body, and opens into the lowest part of the right atrium 54, its orifice 53a being directed upward and backward, and guarded by a rudimentary valve, the valve of the inferior vena cava (Eustachian valve, not shown).

(8) The right ventricle 55 has a triangular in form, and extends from the right atrium 54 to near the apex 59 of the heart 50.

(9) The right atrioventricular orifice (not depicted in FIG. 1) is the large oval aperture of communication between the right atrium 54 and ventricle 55, and is guarded by the tricuspid valve 60.

(10) The opening 61 of the pulmonary artery 62 is circular in form, and is placed above and to the left of the atrioventricular opening; it is guarded by the pulmonary valves 63.

(11) The tricuspid valve 60 consists of three about triangular cusps or segments or leaflets 64, the anterior, posterior and medial or septal cusp. Their bases are attached to a fibrous ring (not depicted in FIG. 1) surrounding the atrioventricular orifice and are also joined to each other so as to form a continuous annular membrane. Their atrial surfaces are directed toward the blood current from the atrium 54, while their ventricular surfaces are directed toward the wall of the ventricle 55; together with the apices and margins of the cusps, they give attachment for the chordae tendineae (not depicted in FIG. 1).

(12) As discussed above, the function of the tricuspid valve is to prevent back flow of blood into the right atrium 54; arrows 70 and 71 indicate normal blood flow into the right atrium 54.

(13) The left atrium 56 is smaller than the right atrium 54. The left ventricle 57 is longer and more conical in shape than the right ventricle 55. The left atrioventricular opening (mitral orifice, not depicted in FIG. 1) is placed to the left of the aortic orifice 65, and is guarded by the bicuspid or mitral valve 66.

(14) The aortic opening 65 is a circular aperture, in front and to the right of the atrioventricular opening, and its orifice is guarded by the three aortic valves 67. Reference number 68 designates the aorta.

(15) Separating the left atrial chamber or left atrium 56 from the left ventricle 57, the mitral valve 66 is, as mentioned above, an atrio-ventricular valve, with the mitral annulus 70 constituting the anatomical junction between the ventricle 57 and the left atrium 56; the annulus 70 also serves as insertion site for the leaflet tissue (not shown).

(16) The normal mitral valve 66 opens when the left ventricle 57 relaxes (diastole) allowing blood from the left atrium 56 to fill the decompressed left ventricle 57. During systole, i.e. when the left ventricle 57 contracts, the increase in pressure within the ventricle 57 causes the mitral valve 66 to close, preventing blood from leaking into the left atrium 56 and assuring that all of the blood leaving the left ventricle is ejected though the aortic valve 67 into the aorta 68 and to the body. Proper function of the mitral valve is dependent on a complex interplay between the annulus 70, leaflets and subvalvular apparatus (not depicted in FIG. 1, respectively).

(17) The mitral valve 66 has two leaflets (not shown), i.e. the anterior and the posterior leaflet. As mentioned above, the anterior leaflet has a semi-circular shape, and the posterior leaflet has a quadrangular shape. The motion of the anterior leaflet defines an important boundary between the inflow and outflow tracts of the left ventricle 57. The anterior leaflet is attached to two fifths of the annular circumference, while the posterior leaflet is attached to approximately three fifths of the annular circumference. The posterior leaflet ahs typically two well defined indentations which divide the leaflet into three individual scallops, which are designated as P1, P2, P3; the three corresponding segments of the anterior leaflet are designated with A1, A2, A3. The Indentations aid in posterior leaflet opening during systole.

(18) On the atrial surface of the leaflets there exist two zones, the peripheral smooth zone and the central coaptation zone. The two areas are separated by the gently curved coaptation line between the two leaflets evident from atrial view.

(19) Mitral valve 66 and tricuspid valve 60 regurgitation is present when the respective valves 66, 60 do not close completely, causing blood to leak back into the respective atria 56, 54.

(20) With the device according to the invention, heart valve regurgitation, in particular mitral valve regurgitation is to be treated, and placement of an exemplary embodiment of the device according to the invention is depicted in the attached FIG. 2.

(21) FIG. 2 shows the schematic drawing of the heart as already depicted in FIG. 1. For better understanding, FIG. 2 does not include all of the reference numbers as depicted in FIG. 1, but is meant to show the same features of the human heart 50, with slight differences in the drawings.

(22) As can be seen in FIG. 2, the device 10 according to the invention is placed in the expanded state in the human heart 50. The device as such is shown in more detail in FIG. 3A, and in the following it will be made reference to both, FIGS. 2 and 3A (to 3D); for the sake of better understanding, not all of the features of the device designated in FIG. 3 are designated in FIG. 2, however, the features are nevertheless the same.

(23) In FIG. 2, the exemplary implantable device 10 according to the invention—as shown in more detail in FIG. 3A and as it is possible with alternative shapes of the devices 100, 200, 300 shown in FIGS. 3B, 3C and 3D—is positioned in the left atrium 56 of the heart 50 in an expanded state of the device 10.

(24) The implantable device 10 comprises a stent element 11 consisting of an atrial anchoring stent-portion 12 and an valve-carrying stent-portion 14, wherein the atrial anchoring stent-portion 12 and the valve-carrying stent-portion 14 are fixedly connected with one another, and are preferably integrally formed, i.e. manufactured as one piece.

(25) In the expanded state of the device 10, the atrial anchoring stent-portion 12 of the stent-element 11 has a balloon-like shape 13, or, so to say, a spherical or ball-like shape, made of a stent-frame or stent-mesh 16, which is preferably laser-cut or interwoven or braided from a nitinol tube or nitinol wires.

(26) With its outermost boundary 17, the atrial anchoring stent-portion 12, contacts the walls (not shown) of the left atrium 56, thus securely anchoring the device in the left atrium, without contacting the annulus 70 of the native valve 66. This is accomplished by the atrial anchoring stent-portion 12 of the stent-element 11 having, at its broadest or largest circumference, a diameter d1 which is larger than the diameter 71 of the annulus 70, and by the valve-carrying stent-portion 14 having a cylindrical shape 15 with a continuous diameter D3 along its cylindrical length l, which in turn is smaller than the diameter of the annulus 70 of the native heart valve 66, being mounted on the atrial anchoring stent-portion 12 such, that the atrial anchoring stent-portion does not contact or touch the annulus or reach into the intra-annular space.

(27) Also, due to the valve-carrying stent-portion's 14 smaller diameter d3 it does not contact or touch the annulus 70 of the native valve 66, which is why the remaining yet dysfunctional closing-movement of the native valve 66 is retained.

(28) As mentioned above, the valve-carrying stent-portion 14 has a cylindrical shape 15 with a continuous diameter d3. attached to the valve-carrying stent-portion 14 is a valve element 18. The valve-element 18 comprises a skirt-portion 19 and a valve-portion 20, the skirt-portion 19 being externally mounted to the valve-carrying portion 14, and the valve-portion 20 being internally mounted to the valve-carrying stent-portion 14. The valve-element 18 can be of any suitable material, preferably pericardium. The valve-portion 20 can be, e.g. a tri-, bi-, or monocuspid valve-portion 20, and can be derived, e.g. from a mammal.

(29) It is to be understood that the valve portion 20 has the functions of a native valve, i.e. can open and close as a native valve does. As a consequence, upon implantation of the device 10, 100, 200, 300 of the invention, there are—so to speak—two valves opening and closing, i.e. the native valve and the valve 20 of the device 10, 100, 200, 300, instead of one native (mitral) valve 66. As a consequence, the valve-element 18 supports the closure of the native mitral valve's 66 closure.

(30) According to the invention, the device 10 provides for a valve 20 with diameter d3 smaller than the native valve's annulus 70, which valve 20 will be positioned n an intra-annular position by means of the spherical self-expandable atrial anchoring stent-portion 12 placed inside the left atrium 56 and fixed in the atrium 56 by radial force of the stent-element 11. As the internal atrial main cavity has an almost spherical anatomy, the atrial anchoring stent-portion 12 of the device 10, 100, 200, 300 according to the invention, and using a ball-in-ball radial compression arrangement, provides for the necessary stability to keep the implanted valve device 10, 100, 200, 300 inside the intra annular space without contacting or touching the annular structure 70.

(31) This hybrid solution, i.e. (mitral) valve replacement plus enhanced coaptation, also solves the drawback of the so-called spacer technique, i.e. thrombus formation and stenosis behaviour of the spacer.

(32) The device 10, 100, 200, 300 can be implanted, e.g. via transcatheter means or surgically implanted. When using a catheter, the device 10, 100, 200, 300 according to the invention is loaded onto the catheter in a compressed state, which is retained by a tube or sheath (not shown) guided over the device 10, 100, 20, 300 thus compressing it. The catheter having loaded thereon the device 10, 100, 200, 300 according to the invention, may be introduced via the vessels of the patient and into the heart: For a mitral application, a direct apical access via the left ventricle apex and across the mitral valve to the left atrium is possible, but also a femoral vein or jugular vein access followed by trans-septal crossing to the left atrium and via pulmonic veins with small thoracotomy. For tricuspid application, a femoral vein or jugular vein access via the inferior or superior vena cava to the right atrium is possible. In the respective atrium—upon removal/withdrawing of the sheath—the expandable device 10, 100, 200, 300 is allowed to expand into its expanded state, thereby contacting and forcing itself against the atrial walls. As a consequence, the atrial anchoring stent-portion 12 of the device 10, 100, 200, 300 gets anchored within the atrium 56, while the valve-carrying stent-portion 14 is positioned intra-annular where its valve-element 18 supports the native valve 66.

(33) FIGS. 3B, 3C and 3D show exemplary embodiments 100, 200, 300 of a device. Despite being manufactured differently, they all share the same shape, which is characterized by the balloon-like shape of the atrial anchoring stent-portion 12 and the cylindrical valve-carrying stent-portion 14 attached thereto.

(34) FIG. 3B shows an embodiment, where the atrial anchoring stent-portion is made from stent rings circumferentially meandering in zigzag form, whereby the stent rings, in a longitudinal direction, are connected by additional (nitinol) wires, thus providing for a stent-frame.

(35) FIG. 3C shows an embodiment where the balloon-like shape of the atrial anchoring stent-portion 12 is made from metal wires, preferably nitinol wires, with the wire(s) being outwardly, i.e. convex, finger-like bended or curved.

(36) FIG. 3D shows an embodiment where the atrial anchoring stent-portion 12 is formed from metal wires interwoven or braided into a ball-like/spherical form.

(37) The valve-carrying stent-portions 12 of the different embodiments shown in FIG. 3A to 3D are—substantially—manufactured in the same way, and represent a cylindrical tubular stent frame.