EP1324721A2

EP1324721A2 - Conduit cardiac-valve prosthesis and a method for the production thereof

Info

Publication number: EP1324721A2
Application number: EP01986587A
Authority: EP
Inventors: Josef Jansen; Rudolf F. J. Meess; Sebastian Willeke; Oliver Haller; Christoph Classen
Original assignee: Adiam Life Science AG
Current assignee: Adiam Life Science AG
Priority date: 2000-10-09
Filing date: 2001-10-02
Publication date: 2003-07-09
Also published as: BR0114158A; MXPA03002315A; DE10050099A1; JP2004510546A; WO2002030332A3; CA2423272A1; WO2002030332A2; CN1449265A; CN1203816C; US20030187500A1

Abstract

The invention relates to a conduit cardiac-valve prosthesis. Said prosthesis consists of a cylindrical tube or a tube provided with bulbous projections with an integrated support housing comprising a base ring, which bears at least two stanchions that are orientated substantially in the direction of the ring axis and are connected by an arc-shaped wall that fixes flexible leaflets. The invention aims to improve the physiological properties of said prosthesis. To achieve this, the tube, the support housing and the leaflets consist of a single material, preferably polyurethane or another polymer and form a one-piece body.

Description

description

Conduit heart valve prosthesis and process for its manufacture

The invention relates to a conduit heart valve prosthesis, consisting of a cylindrical or bulge-shaped tube with an integrated support housing with a base ring which carries at least two posts pointing essentially in the direction of the ring axis and connected via an arcuate wall which serves to fasten flexible sails.

The invention further relates to a method for producing a conduit valve prosthesis, wherein for the manufacture of the sails a core body provided with surfaces shaped according to the shape of the sails is immersed several times in a polyurethane solution and the polyurethane film formed on the core body surfaces is dried between the individual dives and then by further joining methods the sails are connected with a hose.

Konduit heart valve prostheses are special heart valve prostheses in which the sails are integrated directly into anatomically shaped stumps, possibly with so-called bulbs.

In order to achieve a quasi-physiological blood flow in which the dynamic flow stress for the blood corpuscles is tolerable, attempts have already been made in the past to use plastics that are biocompatible and, due to their mechanical properties, a largely functional approach to the natural heart valves enable. Process for the production of artificial cardiac flaps are described in EP 0 114 025 B1. Flap sails that have been produced by immersing a correspondingly shaped core in a polyurethane solution once or several times can be glued to the flap housing. When gluing, however, there are inevitably residues of adhesive at the transitions between the valve leaflets and the valve housing and thus unevenness, which can lead to deposits of cellular blood components with subsequent calcification.

As an alternative to this, it is described in the cited document that using a two-part core body, the valve leaflets can first be formed by dipping and then - after inserting another core part - a type of valve housing is produced, also by dipping, with the process during this Connect transitions of the valve leaflets to the valve housing. However, this method is referred to as relatively complex because very precisely matched partial cores have to be used, and layer thickness differences can occur, which can then lead to irregular stresses.

To avoid these disadvantages, EP 0 114 025 B1 proposes to lower a core body (made of stainless steel or plastic) with shaped surfaces designed in accordance with the valve leaflets to be formed, into a first polymer solution with a viscosity in the range from 24 to 192 Pa xs with a very low lowering speed, which prevents bubbles or the like from forming and inhomogeneities in the polymer forming on the core. After complete immersion, the core body with the film on it is pulled out of the solution and dried. This process can be repeated several times depending on the desired layer thickness. In a second polymer solution with a lower viscosity in the range of 1.5-2 Pa xs, the prefabricated valve housing is held in the solution in such a way that the solution can flow out of the interior of the valve housing through outflow openings located at the bottom. The core body covered with the sails is immersed in this second polymer solution and inserted into the valve ring held in this solution. After the parts have briefly lingered in the solution, the core body with the flap housing is removed from the solution and dried. Finally, the heart valve manufactured in this way is withdrawn from the core body. The heart valves manufactured in this way thus consist of a support housing to which several sails are attached. Such a heart valve, which is also provided with a suture ring, is suitable for insertion into a human vessel. In principle, and as mentioned, for example, in WO 97/49356, such constructions can also be used with conduit valve implants, but it is not mentioned in the cited documents how the conduit heart valve prosthesis is to be manufactured.

It is therefore an object of the present invention to provide a conduit heart valve prosthesis of the type mentioned at the outset, which is improved with regard to the physiological property. In particular, such conduit heart valve prostheses should be used for children.

The above object is achieved in that the hose, the support housing and the sails consist of a single material, preferably polyurethane or another polymer, and form an integral body. Under "one Material "should also be understood to mean those embodiments in which, for example, different polyurethanes from the same material groups, possibly with different mechanical properties, are used. Depending on the different requirements for the flexibility and elasticity of the individual conduit components, different material thicknesses and different ones can be used hard or differently flexible polyurethane can be taken into account. Adhesion points between individual, prefabricated parts or other stress zones resulting from the use of different materials can be effectively avoided by uniform use of polyurethane.

Further developments of the Konduit heart valve prosthesis are described in the subclaims.

Thus, the hose ends adjoining the support housing consist of a microporous, fine-fibrillar, elastic polyurethane, which has greater elasticity than the support housing, which is also made of polyurethane.

If necessary, a reinforcing ring can be integrated into the base ring of the support housing, which preferably consists of titanium or a titanium alloy.

To manufacture the conduit flap prosthesis mentioned, the core body (together with the sails located thereon) is aligned in a casting mold, the casting chamber of which has the contour of a support housing, and the support housing is cast onto the sails by injection molding, after which the final in and out on the outlet side to the support housing hose ends by spraying on a corresponding shape be sprayed on. The Konduit heart valve prosthesis production is thus composed of three separate production steps, namely the manufacture of the sails in a dipping / tumbling process, which is known in principle according to the prior art, and two separate injection processes, in which the support body and then the hose ends are each connected to the one before cast components or - if the hose ends have been manufactured separately - the hose ends are glued to the manufactured components (stent with sail).

As an alternative to this, the conduit valve prosthesis is produced according to the invention in such a way that first individual droplets of a polymer solution or droplets or a continuous volume flow of viscous polymerizing multicomponent systems are punctiform, in a row linear, caterpillar-shaped or on a core body provided with surfaces shaped according to the shape of the sails applied flat to the core body, the application dried and the application of the drops or the volume flow and the subsequent drying repeated until the desired three-dimensional polymer body is formed as a sail. Subsequently, the free sail edges are separated, then a surface corresponding to the shape of the sail is pushed onto a counterform, which is designed accordingly to form the downstream part and may also contain bulge-shaped protuberances. A support housing is formed by immersion in a polymer solution or by droplet application in accordance with the above-described method, a metal ring, which preferably consists of titanium or a titanium alloy, is pushed on in the base region of this support housing and this is then immersed with a polymer by immersion in a corresponding solution with drying or enclosed by droplet application, after which both forms for forming hose ends are sprayed with a polymer material, whereby the actual vessel is formed with a fine fibrillar, microporous structure. This fine-fibrillar, microporous structure has pores with a size of about 20 μm to 80 μm. Possibly. fibers can also be oriented in individual layers, the fiber thickness according to one embodiment of the invention being 0.5 μm to 20 μm, preferably 2 μm to 10 μm. According to an alternative embodiment of the invention, a fleece can also be impregnated on the support housing from the outside after a corresponding application of fibers in such a way that the entire cross section becomes a polyurethane film. The outer surface of the support housing (stents) to which the leaflets are attached can be dissolved with a polymer solution or a pure solvent prior to spraying in order to provide better adhesion between the support housing and the fibers. Since the actual vessel is very elastic due to its structure, the counterform (with the bulbs) can first be removed from the mold and then the core body.

An embodiment of the invention is shown in the drawings. Show it

1 is a schematic representation of a conduit

Heart valve prosthesis

Fig. 2 core body as tools for producing the

Konduit heart valve 3 shows a partial longitudinal section through a conduit

Heart valve prosthesis, which is manufactured by means of the tools shown in FIG. 2,

Fig. 4 shows a segment of a cross section (transverse to

Flow direction) and

5 shows a partial longitudinal cross section of the Konduit heart valve prosthesis according to FIG. 3.

The conduit heart valve prosthesis according to FIG. 1 consists of a cylindrical tube 1 with an integrated support housing 2, which has a base ring 21 and three posts pointing essentially in the direction of the ring axis and connected via an arcuate wall which serves to fasten flexible sails 3, 4 and 5 22, 23, 24. All parts mentioned are made of polyurethane. If necessary, a stabilizing titanium ring 6 can also be integrated in the support ring 21.

In principle, the support body and the sails are constructed as described, for example, in WO 97/49356. However, in the present case the aortic valve is an integral part of a conduit valve prosthesis, which can be manufactured as follows:

First, the three sails 3, 4 and 5 are molded onto a core body, which can have, for example, the shape and configuration described in EP 0 114 025 B1. This can be done by repeated dives with intermediate drying until the desired sail thickness is reached. Then the sails are separated on the line labeled 7. The dip mold is then placed in a mold introduced, the inner cavity of which has the shape of the support housing, the titanium ring 6 possibly being mounted in the cavity via appropriate holders. After injection molding the support housing, in which the sails are connected to the support housing at the edge zones 8, 9, the unit consisting of the support housing and the sails is removed from the mold and inserted into a further mold, in which the end pieces of hose 1 are also injection molded or - after separate production - the hose pieces are attached by gluing. A polyurethane is used for all manufacturing processes, although the hardness and flexural strength of the individual materials differ. The hose ends 1 consist of microporous, elastic polyurethane with a significantly greater elasticity than the polyurethane of the support housing 2, which in turn is less flexible than the thin-walled sails 3, 4 and 5.

FIG. 2 shows a core body 30 which has respective shaped surfaces 31 on its front which correspond to the desired geometric shape of the three leaflets to be produced for the aortic heart valve. Furthermore, FIG. 2 shows a body 32 which is designed on its front as a counter-shape to the planar configurations 31 and which has lateral protuberances 33 which correspond to the bulbs to be produced for the later conduit heart valve. The body 32 can optionally have a surface on its front side with which the sails are only touched linearly at the edge of the stent.

To produce the Konduit heart valve, the leaflets 3, 4, 5 are first produced on the shaped surfaces 31 by dipping or dropwise application or by applying a volume flow of a polymer solution, with several dipping or Dosing operations are required. The molded sails are then separated along the free edges of the sail, after which the counterform 32 is pushed onto the sails. Subsequently, a strengthening of the sail restraint in accordance with the stent 2 shown in principle in FIG. 1 is molded on by casting, one or more dipping processes or by dropwise application or application of a volume flow of a polymer solution. In the meantime, a titanium ring 6 is pushed onto the mold 30, which is finally enclosed on all sides by further cast-on, immersion or other metered layers.

Finally, both forms 32 and 30 are sprayed over, so that the actual vessel 34 according to FIG. 3 is formed with the fine-fibrillar, microporous structure. The outer surface of the stent 2 can be dissolved with a polymer solution or a pure solvent before or after the spraying process in order to create better adhesion between the homogeneous stent and the tube ends 1. Since the actual vessel is very elastic due to its structure, the counterform 32 with the bulb 33 can first be removed from the mold and finally the core body 30. The bulbs are identified by reference number 35.

Claims

claims

1. Konduit valve prosthesis, consisting of a cylindrical or bulge-shaped tube (1) with an integrated support housing (2) with a base ring (21) which has at least two, essentially in the ring axis direction (3), over an arcuate, the attachment of flexible sails serving wall supports connected posts (22, 23, 24), characterized in that the hose (1), the support housing (2) and the

Sails (3, 4, 5) made of a single material, preferably

Polyurethane or another polymer, exist and form an integral body.

2. Konduit valve prosthesis according to claim 1, characterized in that the adjoining the support housing (2) hose ends (1) consist of a microporous, elastic polyurethane which has a greater elasticity than the support housing (2), the microporous material Has pores that, when viewed over a large area, have a size of 20 μm to 80 μm.

3. Konduit valve prosthesis according to one of claims 1 or 2, characterized in that in the base ring (21) a reinforcing ring (6) is integrated, which preferably consists of titanium or a titanium alloy.

4. A method for producing a conduit valve prosthesis according to one of claims 1 to 3, in which for the manufacture of the sails (3, 4, 5) a core body provided with surfaces shaped according to the shape of the sails into one Immerse the polyurethane solution several times and the polyurethane film formed on the core body surfaces is dried between the individual dives and then the sails (3, 4, 5) are connected with a hose (1) by further joining processes, characterized in that after the sails have been manufactured ( 3, 4, 5) of the core body in a mold, the casting chamber has the contour of a support housing (2), aligned and that the support housing (2) is cast onto the sail by injection molding and finally on the inlet and outlet sides of the support housing (2) hose ends (1) either sprayed onto a corresponding shape by spraying or hose ends manufactured separately on a separate shape are attached to the support housing by gluing, all materials being made of polyurethane.

Method for producing a conduit valve prosthesis according to one of claims 1 to 3, characterized in that first individual drops or a volume strand of a polymer solution or drops or a volume strand on a core body (30) provided with surfaces shaped in accordance with the shape of the sails made of viscous polymerizing multicomponent systems, applied in a punctiform manner, in a row in the form of a line, caterpillar or flat on the base body or a carrier tool, the application dried and the application of the drops or the volume strand and the subsequent drying repeated until the desired three-dimensional polymer body is designed as a sail film that the free sail edges are then separated, then a surface corresponding to the sail shape of a counterform (32) is pushed on, which is used to form the downstream part is designed accordingly and may also contain bulbous protuberances (33) that a support housing (2) is molded onto the core mold (30) by immersion in a polymer solution or by droplet application or by applying a continuous volume strand, in the base region of this support housing ( 2) a metal ring (6), which is preferably made of titanium or a titanium alloy, is pushed on and this is then enclosed with a polymer by immersion in a corresponding solution and intermediate drying or by application of volume strands or drops and then by finally spraying both forms ( 32, 30) the hose ends (1) are formed or the hose ends are manufactured and glued separately.