HEART VALVE PROSTHESIS

Abstract

A heart valve prosthesis (1), including: a stent framework (2), which can be transferred from a collapsed state into an expanded state, in which the stent framework (2) extends along an axis (A′), wherein the stent framework (2) has a plurality of struts (20, 24), which form a plurality of cells (21a, 21b, 25) connected to one another; and a heart valve (3), which is fixed to the stent framework (2). In accordance with the invention, the thickness (d′) of the struts varies in the peripheral direction (U) of the expanded stent framework (2).

Claims

1. A heart valve prosthesis (1), comprising: a stent framework (2), which can be transferred from a collapsed state into an expanded state, in which the stent framework (2) extends along an axis (A′), wherein the stent framework (2) has a plurality of struts (20, 24), which form a plurality of cells (21a, 21b, 25) connected to one another, and a heart valve (3), which is secured to the stent framework (2), characterized in that the thickness (d′) of the struts varies in a peripheral direction (U).

2. The heart valve prosthesis according to claim 1, characterized in that the heart valve prosthesis (1) is configured to take on a function of a native mitral valve (M), wherein the heart valve (3) of the heart valve prosthesis (1) is a mitral valve (3).

3. The heart valve prosthesis according to claim 1, characterized in that the thickness (d, d′) of the struts (20, 24) varies in the peripheral direction (U), in such a way that the stent framework (2) in the expanded and implanted state has a peripheral cross-sectional contour (23) which is adapted to the mitral valve annulus (Ma) of the mitral valve (M) that is to be replaced.

4. The heart valve prosthesis according to claim 3, characterized in that a cross-sectional contour (23) consists essentially of a flattened first portion (23a) and an arcuate second portion (23b) connected thereto, wherein the flattened portion (23a) extends from a left fibrous trigone (Tr1) to a right fibrous trigone (Tr2), based on the expanded and implanted state of the stent framework (2).

5. The heart valve prosthesis according to claim 1, characterized in that the stent framework (2) comprises first struts (20), which come to lie in a region of a left fibrous trigone (Tr1) and in a region of a right fibrous trigone (Tr2), based on an expanded and implanted state of the stent framework (2), wherein the first struts (20) have a smaller thickness (d′) than second struts (24) of the stent framework (2), which come to lie on a mitral valve annulus (Ma) further away from the left fibrous trigone (Tr1) and the right fibrous trigone (Tr2).

6. The heart valve prosthesis according to claim 5, characterized in that the first struts (20) have a thickness (d′) which lies in a region of 0.5 times to 0.9 times the thickness (d) of the second struts (24), wherein the thickness (d′) of the first struts (20) is optionally 0.8 times the thickness (d) of the second struts (24).

7. The heart valve prosthesis according to claim 5, characterized in that the first struts (20) form two cells (21a) of the stent framework, which are arranged adjacently in a direction of the axis (A′) and are connected to one another via a connection region (26a), wherein the two cells (21a) come to lie in the region of the left fibrous trigone (Tr1), based on the expanded and implanted state of the stent framework (2).

8. The heart valve prosthesis according to claim 7, characterized in that the connection region (26a) has a first and a second edge portion (210, 211), wherein the two edge portions (210, 211) lie opposite one another in the peripheral direction (U), wherein a recess (212) is formed in each edge portion (210, 211), and wherein the two recesses (212) are arranged offset relative to one another in the direction of the axis (A).

9. The heart valve prosthesis according to claim 5, characterized in that the first struts (20) form two further cells (21b) of the stent framework (2), which are arranged adjacently in a direction of the axis (A′) and are connected to one another via a further connection region (26b), wherein the two further cells (21b) come to lie in the region of the right fibrous trigone (Tr2), based on the expanded and implanted state of the stent framework (2).

10. The heart valve prosthesis according to claim 9, characterized in that the further connection region (26b) has a first and a second edge portion (210, 211), wherein the two edge portions (210, 211) lie opposite one another in the peripheral direction (U), wherein a recess (212) is formed in each edge portion (210, 211), and wherein the two recesses (212) are arranged offset relative to one another in the direction of the axis (A′).

11. The heart valve prosthesis according to claim 1, characterized in that the stent framework (2), in order to allow blood to flow out, defines an outflow tract (27), wherein the stent framework (2) at the outflow tract (27) has loops (28, 29) for anchoring the heart valve prosthesis (1) at anterior and posterior cusps (A, P) of a native mitral valve (M), wherein two anterior loops (28) are optionally provided, which are configured to anchor the heart valve prosthesis (1) at the anterior cusp (A) of the native mitral valve (M), and a posterior loop (29) is optionally configured to anchor the heart valve prosthesis (1) at the posterior cusp (P) of the native mitral valve (M), wherein the posterior loop (29) is shorter than the two anterior loops (28) for the anterior cusp (A).

12. The heart valve prosthesis according to claim 1, characterized in that the stent framework (2) has cells (30) at an outflow tract (27) for anchoring the heart valve prosthesis (1), wherein the cells (30) are curved outwardly.

13. The heart valve prosthesis according to claim 1, characterized in that the stent framework (2) has shortened cells (33) on a peripheral edge (310) of an inflow tract (31) of the stent framework (2), wherein the length of the shortened cells (33) is shorter in a direction of the axis (A′) than the length of peripheral cells (34) that are adjacent in the peripheral direction (U), wherein the shortened cells (33) are configured to come to lie in a region of an aortic peak (AP) of a native mitral valve (M) in the expanded and implanted state of the stent framework (2).

14. The heart valve prosthesis according to claim 1, characterized in that the stent framework (2) is expandable, optionally self-expanding.

15. The heart valve prosthesis according to claim 1, characterized in that the heart valve prosthesis (1) is configured to be implanted by means of a catheter.

Description

DESCRIPTION OF THE DRAWINGS

[0036] Further features and advantages of the invention will be explained in the description of the drawings of exemplary embodiments of the invention, which is provided with reference to the drawings as follows.

[0037] FIG. 1 shows schematic views of a mitral valve.

[0038] FIG. 2 shows a stent framework of a heart valve prosthesis according to the invention in a state spread out flat.

[0039] FIG. 3 shows a schematic illustration of a heart valve prosthesis according to the invention in an implanted state.

[0040] FIG. 4 shows a further schematic illustration of a heart valve prosthesis according to the invention in an implanted state.

[0041] FIG. 5 shows a schematic view of a heart valve prosthesis according to the invention.

[0042] FIG. 6 shows a schematic view of a further stent framework of a heart valve prosthesis according to the invention in a state spread out flat.

DETAILED DESCRIPTION

[0043] FIG. 1 shows views of a mitral valve M. The heart valve prosthesis 1 according to the invention is in particular configured to replace a faulty valve M of this type, wherein the prosthesis is displaced laterally by a stent framework 2 of the heart valve prosthesis. The mitral valve annulus Ma forming accordingly has a D-shaped geometry, wherein the stent framework 2 obtains the geometry in the region of the annulus Ma as a result of the provision of struts 20, which in particular are thinner. More specifically, A1 to A3 denote the portions of the anterior valve cusp A, whereas P1 to P3 denote the portions of the posterior valve cusp P. Furthermore, the aortic peak AP and also the left and right fibrous trigone Tr1, Tr2 are shown.

[0044] A cut view of a stent framework 2 according to the invention for the structure of a mitral valve prosthesis 1 is illustrated in FIG. 2. The stent framework 2 has three anchors 100 for the fastening of the commissures of the artificial valve cusps, which are not illustrated here, and also preferably a total of 18 cells 20 and 24 running around radially, wherein the lower part of the stent cells 20 can be provided with extensions, to which additional retaining loops 28, 29 (for example see FIGS. 3 and 4) can be attached. On the whole, the stent cells 20, 24 in this embodiment can be arranged above one another in particular in four rows, and can thus form the stent framework 2 as a whole. What are decisive for obtaining a D-shaped geometry, as mentioned at the outset, are struts 20, 24 of different thickness, which after implantation come to lie in the region of the trigones Tr1, Tr2 (see also FIG. 1), at each of which a region of greatest bend of the cross-sectional contour 23 of the expanded stent framework 2 is present (in the implanted and expanded state the left vertical edge of the cut form is connected to the right edge of the cut form, such that a stent framework 2 is formed accordingly, which extends along a central axis A′ and runs around transversely thereto in a peripheral direction U, wherein the stent framework 2 (based on the axis A′) forms an inflow tract 31 and an outflow tract 27 at the upper and lower ends respectively).

[0045] In order to achieve a suitable curvature of the stent framework 2, the stent thickness d′ of the first stent 20 can be 0.8*d compared to the second stent 24 for example, wherein d specifies the thickness of the struts 24 in all other regions (away from the trigones Tr1, Tr2).

[0046] In addition to the thinner stent struts 20, the connection regions 26b and 26a (not shown) of the individual (thinner) stent cells 21a, 21b are flexible. This makes it possible for the stent geometry to better follow the natural mitral geometry and thus anchor the artificial heart valve better in the annulus Ma.

[0047] For this purpose, provision is preferably made for example so that the corresponding connection region 26b (or 26a) of the thinner stent 20 has a first and a second edge portion 210, 211, wherein the two edge portions 210, 211 lie opposite one another in the peripheral direction U of the stent framework 2, wherein a recess 212 is formed in each edge potion 210, 211, wherein the two recesses 212 are arranged offset relative to one another in the direction of the axis A′ of the stent framework 2.

[0048] For the fixing of the valve 1, loop structures 28 are also preferably attached to the outflow tract 27. Here, two anterior loops 28, for example according to FIG. 3, are attached for the fixing of the anterior cusp A. Here, the loops 28 run from the commissure mounting 100 in the direction of the trigones Tr1, Tr2 so as to be able to be supported there. These loops 28 running at an incline are intended in particular to reduce a hooking with the chordae tendineae CT during implantation. Just one posterior loop 29 is provided in the region of the posterior cusp P (see FIG. 4). This is preferably formed such that it covers the greatest possible area of the cusp P in the distal loop region, without becoming hooked with the chordae tendineae CT during the positioning of the loop 29. Furthermore, the posterior loop 29 is preferably shortened and corresponds in this example approximately to 0.75 times the length of the anterior loop 28.

[0049] What is important for the fixing of the artificial mitral valve 1 is the anchoring with the native cusps (denoted in FIG. 1 by A for anterior cusp and by P for posterior cusp). This can be provided generally by use of large loops (see also FIGS. 3 and 4), which are attached in the outflow tract 27 of the heart valve 1. It is also possible according to FIG. 5 to design the cell geometry such that part 30 of the cell-forming struts 40 can be curved outwardly. The remaining part of the struts 40 then forms the respective cell. It is thus possible to provide an additional anchoring mechanism in the outflow tract 27 of the stent framework 2, which anchoring mechanism protects the artificial valve 1 against a possible dislocation.

[0050] A further cut view of a stent framework 2 is shown in FIG. 6, the stent framework having been adapted to the asymmetrical conditions in the region of the mitral annulus (for example by use of the above-described thinner struts 20). The cells 33 are also shortened at the edge 310 of the inflow tract 31 in the region of the aortic peak AP (see FIG. 1) compared to the adjacent cells 34 on either side. Furthermore, the integrated retaining loops 28, 29 again have a different length in the direction of the axis A′. The retaining posterior loop 29 of the posterior cusp P is thus shorter than the two retaining anterior loops 28 of the anterior cusp A. The posterior loop 29 is for example 0.75 times as long here as the corresponding anterior loop 28. Here, it should be noted that an asymmetric D-shape can be impressed on the stent framework 2 in FIG. 4, also with heatsetting. In contrast thereto, the stent framework 2 in FIG. 2 can have a radially symmetrical starting form in the pure expanded state, wherein it can adapt to the D-shape of the natural mitral annulus M on account of the different mechanical properties of the stent framework 2 (caused by the struts 20, 24 of different thickness or the connection regions 26a, 26b).

[0051] It will be apparent to those skilled in the art that numerous modifications and variations of the described examples and embodiments are possible in light of the above teaching. The disclosed examples and embodiments may include some or all of the features disclosed herein. Therefore, it is the intent to cover all such modifications and alternate embodiments as may come within the true scope of this invention.