Aortic valve prosthesis

Abstract

The invention relates to an aortic valve prosthesis which is designed for transcatheter implantation, having a foldable valve frame (4) which has three commissures (6) between which three valve leaflets (2) are arranged, wherein the commissures (6) each transition, at their ends, into a commissure holding bracket (14), the ends of the commissure holding brackets (14) that are remote from the commissures are connected together at a common connecting point (16), and the connecting point (16) forms a free end of the aortic valve prosthesis at which a holding element (22) is arranged, which is configured such that it can be grasped by a tool.

Description

Title: Aortic valve prosthesis Description

[0001] The invention relates to an aortic valve prosthesis designed for transcatheter implantation.

[0002] Such a biological aortic valve prosthesis is known, for example, from EP 3 579 788 B1. Such aortic valve prostheses have a foldable valve frame to which three valve leaflets made of biological or synthetic material are attached. The valve frame is folded or compressed together with the valve leaflets in such a way that it can be implanted in the heart using a catheter. Correct positioning of the heart valve prosthesis within the existing aortic valve is of great importance during transcatheter implantation.

[0003] It is an object of the invention to provide an improved aortic valve prosthesis which is designed for transcatheter implantation, which can be positioned very precisely in the heart and, if necessary, can be removed again after complete implantation.

[0004] This object is achieved by an aortic valve prosthesis having the features specified in claim 1 and by an assembly tool having the features specified in claim 13. Preferred embodiments emerge from the subclaims, the following description, and the accompanying figures.

[0005] The aortic valve prosthesis according to the invention is designed to replace the aortic valve in the heart by transcatheter implantation and for this purpose has a foldable valve frame, which is preferably made of a shape memory metal and is self-expanding. This valve frame defines three commissures, between which three valve leaflets, preferably made of biological material, are usually arranged. The valve frame can be covered with a textile material in a known manner, and the valve leaflets are connected, preferably sewn, to the valve frame, in particular the commissures and / or the surrounding textile material. The commissures of the valve frame or stent framework are preferably movable or elastically deformable in order to support or facilitate the movement of the valve leaflets during the opening and closing of the heart valve and to reduce the mechanical stress on the valve leaflets.

[0006] According to the invention, the commissures are designed such that they do not end at a free end, but rather merge into a commissure retaining bracket at these otherwise free ends. This means that the commissures merge into a commissure retaining bracket at those ends which face the contact edges of the valve leaflets defining the opening of the valve. This is the downstream end of the commissures in the direction of flow in the heart. The ends of the commissure retaining brackets facing away from the commissures, i.e. the downstream ends in the direction of flow, are connected to one another at a common connection point. The connection point defines a free end of the aortic valve prosthesis. This free end is free after implantation and does not serve as an attachment point for fastening elements or structures. This means that the connection point has no further connection to the surrounding tissue, particularly in the implanted state.The aortic valve prosthesis according to the invention is thus preferably fixed to the surrounding tissue only at the upstream axial end facing away from the connection point. At this upstream region or end. The aortic valve prosthesis preferably has greater stiffness in the radial direction than the downstream end. This upstream attachment region anchors itself to the surrounding tissue - the aortic annulus and other nearby anatomical structures - preferably through self-expansion and can also be actively pushed radially outwards during implantation in order to clamp itself to the surrounding tissue. At the free end of the aortic valve prosthesis defined by the connection point, a holding element is arranged which is designed such that it can be gripped by a tool. This makes it possible to grasp the aortic valve prosthesis again during or after implantation, after it has already been released from the catheter, in order to be able to reposition it or to correct the positioning.This can significantly improve implantation, as the aortic valve prosthesis can be positioned more precisely. In extreme cases, the aortic valve prosthesis can be retracted into the catheter and removed from the body, for example, to subsequently insert a better-fitting aortic valve prosthesis.

[0007] In one possible embodiment, the aortic valve prosthesis can be designed with a supra-annular valve function, in which the valve leaflets are located above or downstream of the original aortic valve, e.g. 5 to 15 mm downstream of the original aortic valve.

[0008] The valve frame is preferably designed such that the strength in the radial direction or the elastic expansion force in the radial direction in the region of the downstream end of the valve frame, ie in particular in the region of the commissure retaining bracket, is lower than in a further upstream region, in particular than in the fastening region. This facilitates re-engagement and Retraction of the aortic valve prosthesis into the catheter is easier, as the end to be grasped is easier to deform. Furthermore, this design promotes elastic deformability of the commissures, thus reducing mechanical stress on the valve leaflets. Easier deformability due to lower radial stiffness also facilitates possible reworking of the aortic valve prosthesis, for example, with the aid of a balloon or during a repeat valve implantation (TAVI within TAVI).

[0009] The retaining element is preferably provided with at least one undercut; more preferably, it is designed as a hook, ball, or eyelet. This allows it to be engaged by a corresponding engagement element, which is arranged on a suitable tool, in order to retract the aortic valve prosthesis into the catheter.

[0010] According to a further particular embodiment of the invention, the valve frame has at least one valve protection structure in the region between each of two commissures. This means that three valve protection structures are also provided on the aortic valve prosthesis, each in the region of one of the three valve leaflets. The valve protection structures are each designed such that they move radially inward when the valve frame is folded. In this way, the valve protection structures can prevent the central regions of the valve leaflets, i.e. the regions of the valve leaflets located between two commissures, from becoming trapped between the commissures during folding. The valve leaflet is preferably pressed radially inward by the valve protection structure or held radially inward and thus protected from damage during folding.This is particularly advantageous when the aortic valve prosthesis, after being deployed in the heart, is retracted back into the catheter via the holding element and the connecting brackets in order to reposition it. During this refolding process, no additional tools are available to precisely fold the valve leaflets. The valve protection structures take care of this and ensure that the valve leaflets are not damaged in any way during the folding process.

[0011] The valve frame is preferably designed such that the adjacent commissures merge into an arc at their end facing away from the retaining bracket, i.e. a frame arc which connects the commissures to one another. The valve leaflet is fastened in the region of this arc. The valve protection structures preferably extend between two commissures, starting from a frame arc connecting these commissures. This means that the valve protection structure extends from the frame arc essentially in the same axial direction as the commissures, i.e. in the downstream direction. The end of the valve protection structure facing away from the frame arc or spaced apart from them is then located between the tips of two commissures, but more preferably has no direct connection to the commissures.This means that the valve protection structures each form a free element independent of the commissures, which can move particularly preferably independently of the commissures.

[0012] The flap protection structures are further preferably each formed by one or more webs or struts of a lattice structure of the flap frame. They are particularly preferably formed integrally with the lattice structure of the remaining flap frame. This makes it possible to manufacture the entire lattice structure of the flap frame, including the flap protection structures, as a single component, for example, by cutting it from a tube.

[0013] According to a further possible embodiment of the invention, the valve protection structures are each connected at one end to a structure retaining bracket extending towards the connection point. The structure retaining brackets can each be guided directly to the connection point and connected to it. Alternatively, it is possible for the structure retaining brackets to be connected to the commissure retaining brackets via connecting struts. The connecting struts run essentially in the circumferential direction. The structure retaining brackets thus each connect a valve protection structure directly or indirectly to the connection point. The structure retaining brackets are particularly preferably each formed integrally with the valve protection structure.The structural retaining clips are further preferably shaped such that, when the aortic valve prosthesis is retracted, they cause the valve protection structures to move radially inward, just as the commissures are moved radially inward by the commissure retaining clips. The valve protection structures and their structural retaining clips are further preferably designed such that they move radially inward in front of the commissures. This ensures that the valve leaflets are moved radially inward in their central regions or are held radially inward, thus ensuring a defined folding of the valve leaflets.

[0014] According to a further preferred embodiment, the commissure retaining brackets and / or the structural retaining brackets each have at least one section that extends at an angle of less than 90° and preferably less than 60° to the longitudinal axis of the aortic valve prosthesis, which extends in the direction of flow. Such an acute angle is preferably directed such that the angled sections approach one another toward the connection point. When the valve frame is grasped at the connection point and pulled in a catheter, the angled sections can slide along the front side of a catheter opening. Due to the oblique extension In this way, a radially inwardly directed force is generated relative to the longitudinal direction, which serves to deform and compress the valve frame radially inwards so that its diameter is reduced again relative to the longitudinal axis and, in extreme cases, can be moved back into the catheter.

[0015] In a further possible embodiment, the commissure retaining brackets and / or the structure retaining brackets can each have a first section which extends in extension of the connected commissure or valve protection structure, i.e. substantially parallel to the longitudinal axis of the aortic valve prosthesis. According to this embodiment, the commissure retaining brackets and / or the structure retaining brackets furthermore have a second section adjoining the first section which extends at an angle to the longitudinal axis towards the connection point. This section preferably extends at an acute angle, as described above. The first sections ensure that the second sections and the connection point are spaced sufficiently far apart in the axial direction from the valve leaflets and the commissures that the movement of the valve leaflets during opening and closing is not impaired.The oblique or angled second sections serve, as previously described, to reduce the diameter of the valve frame when it is drawn into a catheter. The structural retaining brackets can be configured to comprise only the first section and, instead of the second section, to have the connecting struts that connect to the commissure retaining brackets. The connection to the commissure retaining brackets preferably occurs in their first section or in the transition area between the first and second sections.

[0016] The commissure retaining brackets and / or the structural retaining brackets are further preferably each designed as one-piece webs. The webs preferably have a larger cross-section than the other webs of the lattice structure of the valve frame. The retaining brackets can thus be designed to be stiffer in order to be able to generate a sufficient radially inwardly directed force for folding the lattice structure. The retaining brackets are therefore preferably each formed by a single web. Alternatively, however, the retaining brackets could also be formed from several webs, for example extending parallel to each other. Since the retaining brackets lie in the free flow cross-section through the aortic valve prosthesis, it is preferable to design the retaining brackets as narrow as possible transversely to the flow direction so that they create the lowest possible flow resistance for the blood.

[0017] The commissure retaining brackets are preferably each formed integrally with the structure of the connected commissure, and / or the structure retaining brackets are preferably each formed integrally with the connected valve protection structure. Thus, the retaining brackets can be formed integrally with the remaining structure of the valve frame, for example, cut from a tube. This allows for particularly high strength while simultaneously enabling simple production.

[0018] The connection point can be located centrally with respect to the central axis of the aortic valve prosthesis. This achieves a substantially symmetrical design, which allows for uniform folding of the valve frame starting from the connection point. However, it is also conceivable to position the connection point radially spaced, i.e., eccentrically, to the central axis of the aortic valve prosthesis. This can be advantageous in order to to create sufficient space to allow for the later insertion of another aortic valve prosthesis into the interior of the aortic valve prosthesis.

[0019] The connection point is preferably spaced axially from the plane in which the ends of the commissures are located, and preferably from the plane in which the free edges of the valve leaflets are located. Thus, the mobility of the valve leaflets and the function of the aortic valve prosthesis are not impaired by the retaining clips and the connection point.

[0020] In addition to the aortic valve prosthesis described above, the invention also relates to an assembly tool suitable for implanting an aortic valve prosthesis as described above. The aortic valve prosthesis and the corresponding assembly tool enable a novel implantation method that allows the aortic valve prosthesis to be repositioned during implantation by grasping and folding the aortic valve prosthesis again, as described above. The assembly tool provided for this purpose comprises a catheter that receives the aortic valve prosthesis and a handling element that can be moved linearly inside the catheter.The handling element is movable such that the aortic valve prosthesis can be pushed out of an open end of the catheter, but can also be retracted into the opening, as described above. The retaining brackets slide along the edge of the opening in the manner described above, whereby the aortic valve prosthesis is folded back together or compressed radially. The handling element has an engagement element at its free end, which is designed such that it can releasably engage with the retaining element of the valve frame. Thus, the engagement element can be The holding element can be released once the aortic valve prosthesis is correctly positioned. Particularly preferably, the holding element and the engagement element are configured to correspond to one another in such a way that they can be repeatedly releasably engaged. This means that the engagement element and the holding element are preferably configured such that the holding element can be grasped via the engagement element in order to move the aortic valve prosthesis back into the catheter and, if necessary, reposition it.

[0021] The invention is described below by way of example with reference to the accompanying figures, in which: Fig. 1 schematically shows an aortic valve prosthesis according to the invention, Fig. 2 the valve frame of an aortic valve prosthesis according to a second embodiment, Fig. 3 is a sectional view of the flap frame according to Figure 2, Fig. 4 shows the valve frame of an aortic valve prosthesis according to a third embodiment, and Fig. 5 the flap frame according to Figure 4 in a sectional view.

[0022] Figure 1 schematically shows the overall structure of an aortic valve prosthesis according to the invention. This aortic valve prosthesis is designed to replace the aortic valve in the heart during a transcatheter implantation. The aortic valve prosthesis shown is designed as a pocket valve with three valve leaflets 2. The valve leaflets 2, which can be made of biological or synthetic material, for example, are attached to a valve frame 4. The valve frame 4 is, as will be explained in more detail with reference to Figures 2 to 5, designed as a metal lattice structure which can be folded together such that the aortic valve prosthesis can be implanted via a catheter. The valve frame 4 defines three commissures 6, which are connected to one another by connecting arches 8. The connecting arches 8 connect the commissures 6 at their upstream ends, as seen in the flow direction S. The valve leaflets 2 are attached to the commissures 6 and the connecting arches 8, for example by sewing. The valve leaflets 2 lie tightly against one another at their free edges 10 in the closed state. In the open state, the edges 10 are spaced apart from one another.

[0023] At its axial end facing away from the edges 10 in the direction of the longitudinal axis X, i.e. the upstream end, the aortic valve prosthesis has a fastening region 12 with which it is clamped in a blood vessel, in particular in the region of the natural valve annulus. For this purpose, the fastening region 12 is pressed radially outwards so that it clamps against the wall of the blood vessel. This widening can be achieved in a known manner by elastic restoring forces of the valve frame 4 or, for example, by a balloon placed inside. In this respect, the aortic valve prosthesis described so far corresponds to a known design. The fastening region 12 can also be designed so as to be force-decoupled from the part of the valve frame 4 forming the commissures 6, so that the fastening region 12 can deform without leading to undesired deformations of the commissures 6 and the valve leaflets 2.According to the invention, the valve frame 4 has three commissure retaining brackets 14, which extend from the commissures 6. The commissure retaining brackets 14 are designed as. one-piece metallic brackets are formed, which extend in the axial extension of the commissures 6 to a common connection point 16. This common connection point 16 is spaced in the axial direction X in the flow direction S from the axial ends of the commissures 6 and also from the edges 10 of the valve leaflets 2, so that the function of the valve leaflets 2 is not impaired by the commissure retaining brackets 14. The commissure retaining brackets 14 each have a first section 18 and a second section 20. The first section 18 extends axially, i.e. essentially parallel to the longitudinal axis X in extension of the adjacent commissure 6. The second section 20 extends from the first section 18 to the connection point 16 at an acute angle, i.e. at an angle of less than 90° to the longitudinal axis X.

[0024] The commissure retaining brackets 14 are connected at the connection point 16 to a retaining element 22, here in the form of an eyelet. The aortic valve prosthesis can be grasped by the retaining element 22 and pulled into a catheter in the direction of the longitudinal axis X. The second sections 20 come into contact with the edge of a catheter opening, so that they are pressed radially inward due to their oblique course to the longitudinal axis X. The commissure retaining brackets 14 are thus pressed radially inward, and in this way the entire aortic valve prosthesis can be reduced in its diameter or cross-section transverse to the longitudinal axis X. The attachment region 12 can also be moved out of contact with the surrounding tissue, thus enabling repositioning and removal of the aortic valve prosthesis.

[0025] Figures 2 to 5 show further examples of flap frames 4. In these views, only the flap frame 4 is shown without a textile covering and without the flap leaflets 2.

[0026] The valve frame 4 shown in Figures 2 and 3 essentially corresponds to the valve frame 4 described with reference to Figure 1, but additionally has a valve protection structure to protect the valve leaflets 2 when folding. Figure 3 shows a sectional view of the valve frame 4 in Figure 2, in which only two commissures 6 and a connecting arch 8 located between them can be seen. In the illustration of the valve frame 4, it can be seen that the valve frame 4 is designed as a metallic lattice structure, with the commissure retaining brackets 14 being formed integrally with the remaining lattice structure and as a whole with the lattice structure that defines the commissures 6 and the connecting arches 8. Such a lattice structure can, for example, be cut from a metallic tube. Shape memory metals, such as nitinol, are particularly preferably used as the metal.

[0027] A valve protection structure 24 is arranged on each of the connecting arches 8. The valve protection structures 24 each extend from the lowest point of the connecting arches 8 in the axial direction, i.e. essentially parallel to the longitudinal axis X. In the example shown, each valve protection structure 24 is formed by two webs 25, which each converge in a V-shape starting from a connecting arch 8 and merge into a structure retaining bracket 26. The transition region between the webs 25 and the structure retaining bracket 26 lies approximately at the axial height of the tips of the commissures 6. The webs 25 and thus the tips of the valve protection structures 24 are spaced apart from the commissures 6 in the circumferential direction, such that the commissures 6 can move independently of the valve protection structures 24. The structural retaining brackets 26 have a similar shape to the commissure retaining brackets 14 and are also connected to the connection point 16.The structural retaining brackets 26 with the adjoining flap protection structures 24 protect the flap leaflets 2. when folding and cause the central regions of the valve leaflets 2 to move radially inward when the aortic valve prosthesis is folded or compressed, without being clamped between the commissures 6 moving towards one another. The webs 25 of the valve protection structures 24 come into contact with the surfaces of the valve leaflets 2 in their central region between the commissures 6. Particularly preferably, the structure holding brackets 26 are shaped such that they move radially inward in front of the commissure holding brackets 14 when the valve frame 4 is folded, so that the valve protection structures 24 move radially inward before the commissures 6 move radially inward. In this way, a defined folding of the valve leaflets 2 can be realized.

[0028] Figures 4 and 5 show a further exemplary embodiment of a valve frame 4 of an aortic valve prosthesis according to the invention. The valve frame 4 shown in Figures 4 and 5 essentially corresponds to the valve frame shown in Figures 2 and 3; only the structural retaining brackets 26 are designed differently from the exemplary embodiment according to Figures 2 and 3. For all other features, reference is made to the preceding description. In the exemplary embodiment according to Figures 4 and 5, the valve protection structures 24 are also formed by two webs 25 extending in a V-shape toward one another, with the two webs 25 each merging into a structural retaining bracket 26 that extends in the axial direction parallel to the longitudinal axis X. In contrast to the preceding exemplary embodiment, however, the three structural retaining brackets 26 do not extend to the connection point 16 of the commissure retaining brackets 14, but rather each divide into two connecting struts 28.This means that the structural retaining brackets 26 end in the axial direction before the connection point 16. The connecting struts 28 are connected to the axial end of the structural retaining brackets 26 facing away from the webs 25. The connecting struts 28 extend in the direction of... essentially in the circumferential direction from a structure retaining bracket 26 to a commissure retaining bracket 14. In contrast to the second exemplary embodiment according to Figures 2 and 3, this shape enables a larger free cross-section in the valve frame 4. Furthermore, the shape has the effect that when pressure is applied to the second sections 20 of the commissure retaining bracket 14 via the connecting struts 28, the valve protection structures 24 are moved radially inwards before the commissures 6 move inwards, so that the valve leaflets 2 are folded in a defined manner.

[0029] The aortic valve prosthesis according to the invention thus has a valve frame 4, which enables repositioning during implantation, since the valve frame 4 can be grasped again by the holding element 22 and pulled into a catheter. The entire valve frame 4 is radially compressed or folded again via the commissure holding brackets 14 and, if applicable, the structural holding brackets 26, so that its diameter or cross-section is reduced transversely to the longitudinal axis X and can be repositioned inside a vessel. For this purpose, a tool is preferably provided which has an engagement element designed to correspond to the holding element 22 in order to releasably engage with it. List of reference symbols 2 flap sails 4 flap frame 6 commissures 8 connecting arches, frame arches 10 edges of the valve leaflets 2 12 Mounting area 14 commissure retaining brackets 16 connection point 18 first section 20 second section 22 Holding element 24 Flap protection structure 25 bars 26 structural support brackets 28 connecting struts S Flow direction X Longitudinal axis

Claims

Claims 1. Aortic valve prosthesis which is designed for transcatheter implantation, with a foldable valve frame (4) which has three commissures (6) between which three valve leaflets (2) are arranged, characterized in that the commissures (6) each merge at their ends into a commissure holding bracket (14), the ends of the commissure holding brackets (14) facing away from the commissures (6) are connected to one another at a common connection point (16), and the connection point (16) forms a free end of the aortic valve prosthesis, on which free end a holding element (22) is arranged which is designed such that it can be gripped by a tool.

2. Aortic valve prosthesis according to claim 1, characterized in that the holding element (22) is provided with at least one undercut and is preferably designed as a hook, ball or eyelet.

3. Aortic valve prosthesis according to one of the preceding claims, characterized in that the valve frame (4) has at least one valve protection structure (24) in the region between two commissures (6), which is designed such that the valve protection structure (24) moves radially inwards when the valve frame (4) is folded together.

4. Aortic valve prosthesis according to claim 3, characterized in that the valve protection structure (24) extends from a frame arch (8) connecting two adjacent commissures (6) and having an end spaced from the frame arch (8), which is located between the tips of two commissures (6) and is preferably without a direct connection to the commissures (6).

5. Aortic valve prosthesis according to claim 3 or 4, characterized in that the valve protection structures (24) are each formed by one or more webs of a lattice structure of the valve frame (4).

6. Aortic valve prosthesis according to one of claims 3 to 5, characterized in that the valve protection structures (24) are each connected at one end to a structure retaining bracket (26) extending to the connection point (26).

7. Aortic valve prosthesis according to one of the preceding claims, characterized in that the commissure retaining brackets (14) and / or the structural retaining brackets (26) each extend in at least one section (18, 20) at an angle to the longitudinal axis (X) of the aortic valve prosthesis at an angle of less than 90° and preferably less than 60°.

8. Aortic valve prosthesis according to one of the preceding claims, characterized in that the commissure retaining brackets (14) and / or the structure retaining brackets (16) each have a first section (18) which extends in extension of the connected commissure (6) or valve protection structure (24), and an adjoining second section (20) which extends at an angle to the longitudinal axis (X) to the connection point (16).

9. Aortic valve prosthesis according to one of the preceding claims, characterized in that the commissure retaining brackets (14) and / or the structural retaining brackets (26) are each designed as one-piece webs.

10. Aortic valve prosthesis according to one of the preceding claims, characterized in that the commissure retaining brackets (14) are each formed integrally with the structure of the connected commissure (6) and / or the structure retaining brackets (26) are each formed integrally with the connected valve protection structure (24). 1 1. Aortic valve prosthesis according to one of the preceding claims, characterized in that the connection point (16) is located centrally or radially spaced from the central axis of the aortic valve prosthesis.

12. Aortic valve prosthesis according to one of the preceding claims, characterized in that the connection point (16) is spaced in the axial direction from the plane in which the ends of the commissures (6) are located.

13. Assembly tool for implanting an aortic valve prosthesis according to one of the preceding claims, characterized by a catheter receiving the aortic valve prosthesis and a handling element which is linearly movable inside the catheter, wherein the handling element has an engagement element at its free end which is designed such that it can engage the holding element (22) of the valve frame (4) in a releasable, preferably repeatedly releasable, manner.

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