DE20003874U1 - Device for fastening and anchoring heart valve prostheses - Google Patents

Description

Pfenning, Meinig & Partner GbR Patent Attorneys

European Patent Attorneys European Trademark Attorneys

Dipl.-lng. J. Pfenning (-1994) Dipl.-Phys.K.H.Meinig(-1995) Dr.-lng. A. Butenschön, Munich Dipl.-lng. J. Bergmann* Berlin Dipl.-Chem. Dr. H. Reitzle, Munich Dipl.-lng. U.Grambow, Dresden Dipl.-Phys. Dr. H. Gleiter, Munich

'also lawyer

80336 Munich, Mozartstraße 17 Telephone: 089/53093 36 Fax: 089/53 22 29 e-mail: muc@pmp-patent.de

10707 Berlin, Kurfürstendamm 170 Telephone: 030/8844 810 Fax: 030/8813689 e-mail: bln@pmp-patent.de

01217 Dresden, Gostritzer Str. 61-63 Telephone: 03 51/8718160 Fax: 03 51/8718162 Dresden,

28 Feb. 2000 00/36034-IOFG

FRAUNHOFER SOCIETY

for the promotion of applied research e.V. Leonrodstraße 54

80636 Munich

"Device for fixing and anchoring heart valve prostheses"

FhG 00/36034-IOFG

Device for fixing and anchoring heart valve prostheses

The invention relates to a device for fastening and anchoring heart valve prostheses, which is essentially made of wire-shaped elements connected to one another. In a folded state, it can be introduced through the aorta in a minimally invasive manner and anchored in the aortic wall after unfolding, so that the implanted and fastened heart valve prosthesis can take over the function of the body's own heart valve.

0 So far, it has not been possible to propose a solution that can ensure both a secure seal against the aortic wall and a secure hold. Such a device or anchoring support (stent) must be able to be folded up small enough to be stretched at the implantation site. However, the known solutions do not achieve sufficient enlargement with the appropriate tension to ensure hold. Even proposals that use a shape memory metal do not meet the requirements, although these materials expand when a critical temperature is reached or exceeded.

FhG 00/36034-IOFG 2

The solution described in US 5,411,552 also cannot meet the requirements because a relatively unstable structure is to be used.

Another problem that has not yet been solved satisfactorily is the secure attachment of an artificial or biological heart valve prosthesis. The prostheses are usually sewn to a stent in a complex process. This is time-consuming and must be done with great care to avoid damage.

Since the implanted heart valve prostheses must remain functional over long periods of time, the structural design also plays an important role, since otherwise damage and leaks can occur after implantation, which can lead to life-threatening conditions for the patient.

It is therefore an object of the invention to propose a device 0 for fastening and anchoring heart valve prostheses, which can be folded up small for a minimally invasive implantation through the aorta and unfolded at the implantation site, whereby a secure hold and a secure seal against the aortic wall is ensured.

According to the invention, this object is achieved with a device according to claim 1.

0 Advantageous embodiments and further developments of the invention can be achieved with the features mentioned in the subordinate claims.

Essential elements of the inventive solution are three identical segments, which consist of

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FhG 00/36034-IOFG 3

formed by directly connected brackets, are connected to one another in an arrangement offset by 120°. At least one curved bracket arranged in the distal direction is used per segment, which is connected on both sides to a proximally retracted bracket arranged between adjacent segments. The connection is made by means of solid body joints at a distance from the distally outermost tip of the distally arranged bracket.

Since the curvature of the proximally retracted bracket is adapted to the curvature of the distal bracket in at least one area, it is possible to use these parts of the two brackets to gently attach the heart valve prosthesis. To do this, the pocket edges of the commissures can be pushed onto these areas and then attached to them with considerably less effort, e.g. by sewing.

However, two curved brackets can also be arranged distally, whereby the corresponding arrangement and design with corresponding achievable advantages will be explained below.

In one version, pairs of brackets can also be used per segment, with the two brackets of a pair being curved in opposite directions and also connected by means of solid-state joints. The solid-state joints also serve the function of pivot bearings around which the brackets of a pair can be pivoted, similar to a seesaw. If a pressure force is exerted on one of the brackets, e.g. by peristalsis of the aorta, this bracket is pivoted in the same direction around the axis of rotation on the solid-state joint. At the same time, the other bracket of the pair is pivoted in the opposite direction.

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FhG 00/36034-IOFG 4

As a result, one of the two brackets is always pressed against the aortic wall, which increases the seal and the hold.

It is advantageous to dimension the brackets of a pair in such a way that the lever ratios in relation to the solid-state joints forming the pivot bearings are as equal as possible, i.e. lever arms of equal length or at least approximately equal length are formed.

Also advantageous are the relatively large distances between the solid-body joints due to the 12 0 ° arrangement of the bracket pairs and the large surface areas also covered by the brackets.

The distal brackets not only serve to secure the heart valve prosthesis but also provide a supporting function.
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The advantages mentioned can be further improved by adding an additional curved bracket arranged distally.

The second distal bracket is curved in its distal area in a manner similar to the first distal bracket. In some cases, these two brackets are designed and shaped in such a way that they run next to each other and gaps are formed between them. They can be connected to each other at the same point where the solid-state joints are arranged as a connection to the bracket curved in the proximal direction. The gaps formed are therefore open in the distal direction and parts of the 5 heart valve prosthesis can be inserted into the gap and inserted.

FhG 00/36034-IOFG 5
will hold.

At least part of a distal bracket is drawn in proximally and guided to a turning point where adjacent brackets are brought together. In the case of two distally arranged brackets, this applies to the distal outer bracket.

To stiffen the heart valve prosthesis and provide another way of attaching it, an angle-shaped, proximally retracted bracket can be used, the curved parts of which are arranged between adjacent brackets and partially follow the respective curvature. These brackets are attached with their distal ends to one distal outer bracket or the distal outer bracket. Here, too, the attachment forms a solid-state joint. However, these should be arranged at a distance from the other solid-state joints connecting the brackets of a 0 pair.

When the device is implanted and stretched, the pockets of a heart valve prosthesis can then be inserted, held and supported.

The bracket construction of the device according to the invention supports a heart valve prosthesis over a large area and therefore gently. In addition, it can be attached with significantly less effort, for example by sewing.

The design solution enables a secure hold and the necessary sealing on or against the aortic wall. For the sealing and a

FhG 00/36034-IOFG 6

Pressing the heart valve prosthesis from the inside using the brackets also has a positive effect on the reduced strain on the heart valve prosthesis.

The device according to the invention can be implanted with a balloon catheter and unfolded at the implantation site. A shape memory metal with a suitable transition temperature is also advantageously used for the device, with which additional expansion can be achieved. An alloy containing nickel and titanium, which is available under the name Nitinol, can be used for this purpose.

In addition, the part of the device that carries and holds the heart valve prosthesis can be implanted separately from a support body, to which reference is made below in the description of an embodiment, without reducing the advantageous properties. The implantation of this part, which essentially consists of the three segments with the heart valve prosthesis attached to them, can then be carried out surgically in a conventional manner.

5 The invention will be explained in more detail below using an embodiment.

It shows:

Figure 1 shows a development of an example of a

0 device according to the invention.

Figure 1 shows a development of an example of a device according to the invention. The device is designed to be radially symmetrical, with three identical segments arranged in a 120° arrangement.

FhG 00/36034-IOFG 7
be applied.

Each segment uses a bracket construction to support and attach an artificial or biological heart valve prosthesis.

In this example, two brackets 4 and 5 are used, which are arranged distally on the outside, whereby the outer bracket 5 could possibly be omitted.

The curved bracket 4 is connected to a bracket 3 bent in the opposite direction. The connections on both sides form solid joints 7, which simultaneously take on the pivot bearing function for the two levers 3 and 4, as already explained in the general part of the description.

The second bracket 3, which is bent outwards and arranged distally, increases stability and offers an additional support and fastening option for the heart valve prosthesis. The two distal outer brackets 4 and 5 are also connected to one another, whereby the connection can be made at the same place where the solid-body joints 7 are arranged.

Between the two brackets 4 and 5 there are gaps open from the distal direction into which parts of the heart valve prosthesis can be inserted and fixed there.

The outer bracket 5 is pulled further inwards in the proximal direction and is connected at its end to a support bar 8. In this example, the support bars 8 5 are parallel to the longitudinal axis of the

riF 2OO 03 87&eegr;·

FhG 00/36034-IOFG 8

Device and, together with sawtooth, diamond or meander-shaped crossbars, they form a support body which, when unfolded, rests against the aortic wall. For hooking, additional tips 9 can be present or formed on the support bars 8 and/or the crossbars, which hook into the aortic wall.

The arrangement and length of the support bars 8 and the correspondingly large distance to the heart valve prosthesis attached in the area of the brackets 3, 4 and 5, enable the heart valve prosthesis to be positioned without closing or covering the coronary vessels.

In the example shown here, between the individual segments used in a 120° arrangement, there are additional proximally retracted brackets 2 that are connected to the distal outer brackets 5. Here too, the connections are solid joints 6, but they should be arranged as far away from the solid joints 7 as possible. This means that two levers can be used per segment and with such a double mirrored structure, approximately twice the forces can be achieved to fix the device.

In the unfolded implanted state, parts of the heart valve prosthesis can be alternately inserted between the parts 1 of the brackets 5 and the brackets 2, and thus supported and attached thereto.

However, the number of brackets used can be increased to improve the hold and further reduce the load on the heart valve prosthesis. 35

Claims (10)

1. Device for fastening and anchoring heart valve prostheses, which is formed from wire-shaped elements, characterized in that for fastening and supporting a heart valve prosthesis, three identical segments are directly connected to one another in an arrangement offset by 120°; on each segment there is at least one curved bracket (4, 5) in the distal direction, which is connected on both sides to a bracket (2) arranged between two adjacent segments and drawn in proximally by means of solid-state joints (6), the solid-state joints (6) being arranged at a distance from the distal tip of the distal bracket (4, 5) and the curvature of the two legs of the bracket (2) being adapted to the curvature of the bracket (4 or 5) at least in one area. 2. Device according to claim 1, characterized in that a segment has a first and a second distally outwardly curved bracket (4 and 5) which are connected to one another by means of solid-state joints (7). 3. Device according to claim 1 or 2, characterized in that the heart valve prosthesis is attached to the first, second distal bracket (4, 5) and/or to the proximally retracted bracket (2). 4. Device according to one of claims 1 to 3, characterized in that the first and second distal brackets (4, 5) are partially bent in the same direction and run parallel to each other, so that gaps are formed between them for the introduction of parts of the heart valve prosthesis. 5. Device according to one of claims 1 to 4, characterized in that the solid-state joints (6) and (7) are arranged at a distance from one another. 6. Device according to one of claims 1 to 5, characterized in that on each segment pairs of brackets (3, 4 or 5) which are curved in opposite directions to each other are connected by means of solid-state joints (7) which fulfil the function of pivot bearings. 7. Device according to claim 6, characterized in that the two oppositely bent brackets (3, 4) form lever arms of equal length in relation to the solid-state joints (7). 8. Device according to one of claims 1 to 6, characterized in that the proximal ends of the first bracket (4) or of a proximally retracted part (1) of the second bracket (5) are connected to one another by support webs (8) aligned parallel to the longitudinal axis, which in conjunction with a sawtooth, diamond or meander-shaped wire structure form a foldable support body. 9. Device according to one of claims 1 to 8, characterized in that tips (9) are formed on the support body for anchoring in the aortic wall. 10. Device according to one of claims 1 to 9, characterized in that all parts (1 to 9) are formed from a shape memory metal.