HK1161535A - Occlusion instrument and method for its production - Google Patents

Abstract

The present invention relates to an occlusion instrument made up of a braid (2) of thin wires or filaments (4), which obtains a suitable shape by means of a shaping and heat treament method. The occlusion instrument (1) has a proximal retention area (6) and a distal retention area (8), the ends of the wires or filaments (4) running together in a holder (5) in the distal retention area (8). Moreover, a cylindrical web (10) is provided between the proximal and distal retention areas (6，8). With the aim of making available an occlusion instrument which, in the inserted state, lies as flat as possible on the proximal face of a septum defect, the invention proposes that the proximal retention area (6) of the braid (2) at the proximal end of the occlusion instrument (1) has a completely closed proximal wall (112) with a continuous surface area that forms the proximal end (12) of the occlusion instrument (1).

Description

Occluder and method for producing same

The present application is a divisional application of a patent application having an application date of 2007, 3 and 22, application No. 200780010436.7, entitled "occluder and method for manufacturing the same".

Technical Field

The invention relates to an occluder consisting of a holder and a braid of thin wires and filaments, which is shaped by means of a shaping and heat treatment process such that the occluder has a proximal retention zone and a distal retention zone, wherein the ends of the wires converge into the holder on the distal retention zone, and a cylindrical crosspiece (crosspace) which is arranged between the proximal and distal retention zones, wherein the two retention zones are usually positioned on both sides of a shunt channel (shunt) to be occluded in the septum by endovascular surgery, while the crosspiece traverses the shunt channel. The invention further relates to a method for producing said occlusion device.

Background

Medical technology has long been dedicated to the ability to seal septal defects, such as atrial septal defects, by non-surgical intravenous catheter intervention, i.e., without the necessity of literal surgery. Various occlusion systems have been proposed, but each has its own advantages and disadvantages, and none has been widely accepted. The term "occluder" (occluder or occlusion device) will be used below when referring to these various systems.

In all interventional occlusion systems, a self-expanding umbrella system (self-expanding umbrellystem) is introduced intravenously into the defect to be occluded in the septum. Such a system may comprise two umbrellas, for example, one umbrella located distal to the septum (i.e., the side furthest from the body/heart bisection) and the other umbrella located proximal to the septum (i.e., the side closer to the body bisection), such that the two umbrella prostheses are mounted as a double umbrella over the septal defect. In the installed state, the occlusion system therefore usually consists of two fixed umbrellas connected to each other by a short rail (short peg) through the defect.

However, a relatively complicated, difficult and complicated implantation method has proven to be a disadvantage of the known prior art occluders. In addition to the complicated implantation method of such an occlusion system into a septal defect to be occluded, the umbrella employed is also very susceptible to material fatigue with fragment breakage. In addition, thromboembolic complications are often expected.

For another occluder, the so-called lock-clamshell umbrella system (lock-clamshell umbrellystem), two stainless steel umbrellas are provided, preferably coated with polyester, each umbrella being stabilized by four arms. Such occluders are implanted in patients via venous vessels. However, a problem with the closure-clam shell umbrella occluder is that the insertion device necessary to implant the occluder needs to be of relatively large size. A further problem is that many different sized occluders are required in order to treat each part of the septal defect to be occluded. The result is therefore that if the length or diameter of the crosspiece (cross) inserted into the defect is not the most suitable match, the umbrella will not be completely flat in the inserted state. This can lead to incomplete endothelialization. Moreover, it has been shown that many systems implanted in patients exhibit fatigue and cracking of the metal structure due to metal stress over extended periods of time. This is particularly true in the presence of permanent tension between the implant and the diaphragm.

To overcome these disadvantages, self-centering occluders (self-centering occluding devices) have been developed which are inserted into a patient by a minimally invasive procedure (e.g., using a catheter or guidewire) and introduced into the septal defect to be occluded. Their design is based on the principle that the occluder can be tapered to the size of the insertion device and/or catheter used for endovascular surgery. The tapered occluders are then introduced via a catheter into the septal defect to be occluded and each into a shunt channel of the septal defect to be occluded. The occluder is then expelled from the catheter, whereupon a self-expanding umbrella, a retention disc(s), will each extend over both sides of the septum. These umbrellas then comprise a fabric insert, for example made of or coated with dacron, through which the defect/shunt channel is blocked. After weeks or months, the body's own tissues more or less completely encase the implant that remains in the body.

An example of such a self-centering occluding device is disclosed in U.S. patent No.5,725,552, which U.S. patent No.5,725,552 describes an occluding device known as an "Amplatz occluder". The known system will be briefly described below with reference to fig. 15a to 15 c. In particular, figure 15a shows a tubular braid as disclosed in the prior art (e.g., the U.S. patent No.5,725,552) as a basic structure or starting body for the manufacture of such known occluders, wherein each end of the tubular braid needs to be held in a separate holder. Figure 15b depicts a cross-sectional side view of the right side of a PFO-type occluder of the prior art (e.g. from said us publication No.5,725,552) made from a tubular braid according to figure 15a, while figure 15c shows a cross-sectional right side view of another ASD-type occluder also disclosed in us patent No.5,725,552 also made from a tubular braid according to figure 15 a.

The term "PFO-type" used therein is understood to mean an occluder for treating a Patent Foramen Ovale (PFO), while the term "ASD-type occluder" refers to an occluder for treating atrial septal defects.

The known occluders consist of a braid in the shape of a yo-yo, which is formed from a plurality of thin, twisted nitinol (nitinol) wires. The initial shape of each braid is made as a circular braid with loose ends at the leading end of the braid (proximal side of the respective braid) and the trailing end of the braid (distal side of the respective braid), which must be gathered into a collar (collar) and welded together during subsequent handling of the circular braid. After appropriate treatment, the finished occluding device has a raised collar on both the distal and proximal sides. The polyester chips were sewn into distal and proximal retention umbrellas (retention umbrellas) and into the inserted rungs. Because of the memory effect of the nitinol material used, when the two retaining umbrellas leave the catheter, they expand themselves, initially in a balloon-like intermediate stage, whereby the retaining umbrellas finally positioned on both sides of the diaphragm assume finally a more or less flattened shape. As the umbrella expands, the crosspiece will self-center itself into the shunt channel to be plugged.

Since the collar bulges past the proximal retention area of the occluder, the problem arises that the inserted implant can lead to associated thrombotic problems, in particular to continuous embolization. Defensive system reactions also occur from time to time as the components of the stopper bulge past the septum wall and continue to contact the blood. Furthermore, complete endothelialization of the occluding device implant is often hindered.

An occluder of the type indicated at the beginning of the present description and a method of manufacturing such an occluder are also disclosed in WO2005/020822a 1. The occluder described in WO2005/020822a1 essentially consists of a braid formed by thin wires or threads made of a material with a shape memory function. In the expanded state, the known occlusion device has a proximal retention zone and a distal retention zone and a cylindrical crosspiece inserted in between.

Since the proximal retention zone of the braid assumes a proximal open shape in this prior art, the occluder substantially allows the edge of the proximal retention zone to be positioned flat on the septum wall when the occluder is in the inserted state and the retention zone does not pass through the septum wall.

The manufacturing method according to WO2005/020822a1 employs a braiding technique by which an open-topped tubular braid is formed, which only needs to be provided at one end thereof with a holder for binding fine wires or filaments of the braid, while at the opposite end, the fine wires or filaments of the braid are wound from their centers. In this way, it is possible to produce a braid which is used as a basic structure of the known occluder, wherein the proximal retention zone of the basic structure assumes a shape which is open at the proximal end.

To further define the occluder disclosed in WO2005/020822a1 in more detail, reference is made to fig. 16a to 16 c. In detail, fig. 16a shows a tulip-or bell-shaped braid with a distal holder as disclosed (e.g. in WO2005/020822a 1). Figure 16b depicts a cross-sectional view of the right side of a PFO-type occluder disclosed in WO2005/020822a1, wherein the occluder is made of a tubular braid according to figure 16 a. Finally, fig. 16c shows another cross-sectional view of the right side of an ASD-type occluder disclosed in WO2005/020822a1, which occluder is likewise made from a tubular braid according to fig. 16 a.

In the case of the occluders disclosed in WO2005/020822a1, it has proved to be disadvantageous that it is necessary to span, for example, a dacron insert or cloth over the opening present at the proximal end of the braid, so that the finished occluder is no longer open at the proximal end. The production of such occluders requires a very complicated manufacturing process and thus the cost of a single occluder is high. In addition, the different materials (i.e., the material of the braid) and the material of the dacron insert or cloth must be press-fitted to each other. Such a connection is an inherent weakness in terms of material fatigue. Thus, this known occluder has a greater risk of material fatigue with fracture of the fragments. Moreover, it has further been shown that the connection of such an implant system between the metal structure and the dacron insert may exhibit material fatigue and cracking when present in the human body for a prolonged period of time, due to the high metal stress. This is particularly true when there is a persistent tension situation between the braid and the insert.

Furthermore, the occluder disclosed in WO2005/020822a1 requires consideration of thromboembolic complications. Although this known system enables the edge of the proximal retention zone to be positioned flat against the membrane wall without the retention zone passing through the membrane wall when the occluder is in the inserted state, the proximal end of this known occluder still exhibits a machining-accompanying opening in the proximal wall in the axial direction of the crosspiece. Even if this opening is closed, for example with a dacron insert (as described above), this known system does not avoid that the finished stopper has at least one retaining groove-like recess or sometimes even a portion that is raised in the proximal retention zone of the stopper, which groove-like recess or raised portion is exactly where the opening with the dacron insert is closed.

The grooved recesses or raised portions entail another problem in that the inserted implant may cause associated thrombotic problems, in particular continuous embolization. These associated thrombotic problems are particularly likely to arise when the patient is suffering from so-called atrial fibrillation. This is a condition that subjects the upper chambers of the heart to stimuli that cause them to not contract. As a result, the left and right portions of the heart fail to contract, the blood does not effectively swirl and mix, and thrombosis is formed in the atria. When atrial fibrillation leads to thrombosis in the atrium, there is a great risk that these thrombi may be carried in the bloodstream and enter the arterial circulation. Stroke occurs in about 5% of patients with atrial fibrillation every year, a particular consequence of the embolic event when not treated with so-called blood coagulation inhibitors (an anticoagulant) for a prolonged period of time. However, there is no risk of preventing blood coagulation with so-called blood coagulation inhibitors. One side effect of treatment with blood coagulation-preventing agents is increased bleeding, so that about 20% of patients with atrial fibrillation have contraindications for this treatment and therefore these patients have to risk stroke when weighing the risk of bleeding/stroke.

Disclosure of Invention

Therefore, the present invention poses problems: the occluder disclosed in the medical art and described in WO2005/020822a1 was modified to overcome the aforementioned disadvantages. A particular object is to provide an occluder which is suitable for occluding defects of different sizes, so that implantation of the occluder is a simple operation. In addition, the concurrent problems of the common occluder, such as dislocation, local embolism or material fatigue of the occluder, are reduced to the greatest extent possible. Beyond this, it is also desirable to provide an occluder which ensures occlusion of septal defects while at the same time leaving little of the occluder's portion able to pass through the septal wall to avoid the aforementioned complications associated therewith.

Based on the problems set forth and proceeding from the system disclosed in WO2005/020822a1, the object of the invention is to provide an occluder which, in the inserted state, can be positioned as flat as possible on the septum proximal to the septum defect and which can greatly reduce the risk of material fatigue with fracture of the fragments and at the same time can be produced at lower production costs. In addition, the invention also provides a technical task of the manufacturing method of the plugging device.

According to the invention, these tasks are achieved by an occluder of the kind specified in the opening part of the present description which is such that the proximal retention zone of the braid has a completely closed proximal wall at the proximal end of the occluder, said proximal wall having a continuous surface (continuous surface) which forms the proximal end of the occluder.

In addition, the processing problem of the present invention is solved by a manufacturing method of the stopper, which is characterized in that: a process step of forming a hollow braid in the shape of a sphere, bulb or tear-drop by a braiding process known per se, and a process step of forming a proximal retention zone, a distal retention zone on the first end of the bundle, and a cylindrical rung interposed between said proximal and distal retention zones. Wherein the hollow braid is defined as being bundled at a first distal end and presenting a fully closed proximal wall with a continuous face at an opposite second proximal end.

The term "proximal wall" as used herein is understood to mean the portion or area of the braid heat-generating proximal retention zone located on the proximal end of the occluding device that forms an occlusion at the proximal end for the defect to be occluded.

A particular advantage of the present invention is to provide an endovascular occluder, particularly for treating septal defects, wherein the occluder is adapted to be manipulated by a catheter to the defect to be occluded. Since the proximal retention zone of the braid has a fully closed proximal wall on the proximal end, which has a continuous face forming the proximal end of the occluder, the occluder offers the particular advantage that it can adjust itself to a defect in the septal wall regardless of the diameter size of the defect to be occluded and the thickness of the septal wall, and in particular that no part of the occluder on the proximal side of the defect protrudes into the septal wall face with the defect. In the solution of the invention, this face, i.e. the septal wall face with the defect, is formed by the fully closed proximal wall of the occluder. On the other hand, the solution of the invention ensures that the proximal wall does not contain notches or other mathematical "discontinuities" such as sharp edges, kinks (kinks) and the like. In any case, the complications normally associated therewith, in particular with regard to the associated thrombotic problems, can thus be eliminated.

The first advantage obtained is that the inserted occluding device will be wrapped by the body's own tissue much faster than would be the case with the use of the occluding systems known in the prior art. A further advantage of the occluder compared to occlusion systems known from the prior art is that it has a better long-term mechanical stability, which results from the use of a braid made of thin metal wires or threads as starting material for the occluder according to the invention. This greatly prevents fractures from occurring within the inserted implant structure. Moreover, the braid has better rigidity because it is made of one material with a unitary structure and no connecting seams.

In particular, since the solution according to the invention makes it possible to completely omit the fabric or polyester insert, which is required, for example, in the case of the closure system disclosed in WO2005/020822a, the premature occurrence of material fatigue can be effectively further reduced, and the overall production costs can be additionally reduced.

In addition, the completely closed proximal wall provided at the proximal retention zone of the braid allows the proximal retention zone of the occluder to lie completely flat against the lateral edge of the defect in the inserted state and in particular to do so substantially irrespective of the diameter of the defect or the thickness of the membrane wall. Thus, the occluding device may be used for a wide range of septal defects of different sizes. Furthermore, since no fixation means for bundling or gathering the braid is required in the proximal retention zone, no part of the occluder will penetrate the septum wall, so that a part of the implant can be prevented from continuously coming into contact with blood. This yields the advantage of not posing any threat of defense mechanism reaction to the human body or of not having any thromboembolic complications.

The method according to the invention offers the prospect of a particularly simple production of the occluder described above. First, a hollow braid in a spherical shape, a bulb shape, or a teardrop shape is formed, for example, using a circular knitting machine. As used herein, the shaped braid is bundled at the trailing end of its length (i.e., which will later become the distal end of the occluding device) while the leading end of the length of the braid (i.e., which will later become the proximal end of the occluding device) is closed. It is thus possible to produce a hollow braid in the form of a "bag", the end of which is bundled corresponding to the distal end of the finished occluder, and the opposite closed end of which corresponds to the proximal end or proximal wall of the finished occluder. Since the known weaving method is used for producing the occluder, the finished occluder exhibits mechanical properties in respect of, for example, expansion, stability, strength, etc., which can be adapted conventionally for the subsequent use of the occluder. In a preferred manner, wires or even fine organic threads can be incorporated into the braid. It goes without saying that the terms "spherical shape", "bulb shape", "teardrop shape" and "bag shape" used therein refer to shapes having a shape similar to a sphere, bulb, teardrop or bag, respectively. The invention is not particularly limited to precise spheres or other shapes.

Preferred embodiments of the invention are specified in the dependent claims 2 to 10 with regard to the stopper itself and in the dependent claims 12 to 13 with regard to the manufacturing process.

Particularly preferably, the proximal wall of the occluder has a continuous surface which is an arc-shaped surface. Thus, the curvature of the face must be free of discontinuities such as edges, corners, and the like. As used herein, the term "continuous" refers to the mathematical definition of a continuous surface as is well known in the art of topology. For example, it is conceivable to present the proximal wall with an arcuate face in relation to the septum wall face with a defect, which preferably has a slightly concave curve to ensure good results, i.e. the proximal wall is flat or even conformed in relation to the septum wall. Of course, it is also conceivable to arrange the surface of the proximal wall preferably slightly convex with respect to the septum wall, thus making the press-fit (force-fit) connection between the proximal wall, respectively the peripheral region of the proximal wall, and the septum wall particularly large at the defect to be occluded, so that a better fixation of the occluder within the defect to be occluded is possible. It is also conceivable to form the outer region of the proximal wall with a slight concavity which transitions into a convex shape towards the middle, i.e. towards the position of the stopper in the axial direction of the crosspiece. This also leads to advantages, in particular with regard to the fixation of the occluder in the defect to be occluded.

In a particularly preferred realization of the latter embodiment, the proximal wall of the occluder has an arcuate face as the continuous face, the arcuate face being defined to conform to a portion of a spherical, bulb-shaped or teardrop-shaped object. That is, this means that the proximal wall of the occluding device may be provided in the shape of, for example, a portion of a spherical cap or a tear drop. Of course, other profiles are also contemplated herein. A particular advantage of the solution according to the invention is that the occluder can be used essentially ideally regardless of the type of defect to be occluded, in particular regardless of the size of the defect to be occluded.

Particularly preferably, the occlusion device has a braid which consists of nitinol or another shape-memory material or material with memory properties. Such other materials are conceivable, for example copper-zinc-aluminium alloys, gold-cadmium alloys, or even iron-based alloys, such as iron-manganese-silicon alloys, or also plastics, all of which are characterized by an extremely high memory capacity.

It is particularly preferred to define the braid of the occluder of the present invention as being formed from a shape memory polymer, for example based on a polyanhydride matrix or hydroxycarboxylic acid. These are synthetic degradable materials with thermally induced shape memory potency. Of course, other shape memory polymers are also contemplated, such as the block copolymers described in the specific edition of Angewandte Chemie 2002, 114, pages2138 to 2162, by A.Lendlein and S.Kelch, Inc., journal of Angewandte Chemie 2002, 114, pages2138 to 2162.

By using such a material, it is possible to use a bag-shaped hollow braid, which is closed at one end and bunched at the other end, produced, for example, in a circular knitting method, as a starting body of the occluder. The starting body is then shaped into the desired shape of the stopper by a forming and heat treatment process. Although other treatment processes are also contemplated herein.

In the latter embodiment of the occluder of the present invention, the braid is made of a shape memory material, which is advantageously further improved to define the shape memory material as a biodegradable shape memory polymer material. Synthetic biodegradable graft materials are particularly suitable. Such degradable materials or polymers contain bonds that are easily broken under physiological conditions. "biodegradation" refers to the degradation of materials by or in biological systems based on the loss of mechanical properties. Under certain conditions, the shape and size of the implant is maintained during degradation. If reference is made to degradation time without adding any additional quantitative information, the degradation time refers to the time taken to completely lose mechanical properties. Biostable materials refer to those materials that remain stable in a biological system and that at least partially degrade in a biological system over time.

In the case of degradable polymers, a distinction is made between hydrolytically degradable polymers and enzymatically degradable polymers. Hydrolytic degradation has the advantage that the degradation rate is independent of the implantation site, since water is not present. In contrast, there are large differences in local enzyme concentrations. In the case of biodegradable polymers or materials, degradation is subsequently allowed to occur by pure hydrolysis, enzyme-induced reactions, or by a combination of both. Typical hydrolysable chemical bonds are amide, esterase or acetal bonds. When degraded, two processes can be observed. In terms of surface degradation, hydrolysis of chemical bonds occurs only at the surface. Due to its hydrophobic nature, polymer degradation proceeds more rapidly than water diffusion inside the material. In the case of the use of poly (anhydrides) or poly (orthoesters), this process can be observed first. For poly (hydroxy carboxylic acids), such as poly (lactic acid) or poly (gluconic acid), the respective individual copolymers are very important for shape memory performance, and the entire amount of polymer will degrade. Since water diffusion occurs relatively rapidly within a relatively hydrophilic polymer matrix, the factor determining the rate of degradation is the cleavage of the hydrolytic bonds. The key to the use of biodegradable polymers is that, on the one hand, the degradation rate can be controlled or varied and, on the other hand, the degradation products are non-toxic.

The present invention claims all biodegradable shape memory polymers described above.

In a development of the occluder of the present invention, it is particularly preferred to taper the occluder to the diameter dimension of a catheter used in minimally invasive surgery. The advantages of this embodiment are in particular: the catheter system for implantation and explantation can be given a significantly reduced inner diameter, which in the first place significantly enhances the operability of the occluding device to be implanted. This also increases the accuracy in positioning the occluder in the defect to be occluded. In the case of a nitinol occluder, the inner diameter of the catheter used in implantation and explantation ranges between 8 French and 10 French, whereas in the case of a polymer composite occluder the inner diameter need only be between 6 French and 8 French.

With regard to the latter described preferred embodiment of the solution according to the invention, according to which the braid of the occluder is tapered to the diameter of the catheter used for endovascular surgery, a further improvement provides for the proximal retention zone of the occluder to be provided with a proximal wall, which is curved outwards when the occluder is expanded and in this way enters into place in the septal wall. This reflects a particularly easy to implement and effective method of forming the proximal wall of the occluding device. It is thus possible to form the entire occluder as a single piece of braid, so that on the one hand no mechanical connecting elements are required between the proximal wall and the crosspiece, and on the other hand the size of the occluder in the folded state can be further minimized. Of course, as can be appreciated herein, there are other embodiments that can be used to form the proximal wall on the proximal retention zone.

In order to provide the occluder of the present invention with a retrievable function, the occluder is preferably further developed to define the distal retention zone with a holder, preferably arranged axially of the crosspiece, wherein the holder has at least one connecting element which is engageable with a catheter. The connecting element is preferably arranged on the distal end of the occluder so that it does not project above the distal end of the septum wall, by means of which connecting element the components of the implant are prevented from continuously coming into contact with blood, and explanting the occluder according to this further improvement becomes a simple operation. At the same time, the connecting element, which is engageable with the catheter, facilitates the implantation and positioning of the occluding device (which is folded during the implantation procedure) within the defect to be occluded. Various mechanical means are conceivable as connecting elements such as engaging members, for example, or even hooks and/or eyelets, which can be press-fitted with correspondingly complementarily configured connecting elements of the catheter.

Another advantageous further development defines that the occluder is arranged to be reversibly collapsible and expandable so that in the expanded state it can be folded back again, for example with the aid of an explanted catheter, so that the press-fit connection formed between the proximal wall of the proximal retention zone, the peripheral region of the proximal wall and the septum wall, respectively, can be released for separation. It is thus conceivable, for example, to engage a catheter with a connecting element at the distal end of the occluder during the implantation and to achieve folding of the occluder by external manipulation by means of the catheter. The occluder can thus be completely reversibly withdrawn in the catheter, which enables complete removal of the occluder.

The method according to the invention offers the prospect of a particularly simple production of the occluder described above. First, a spherical or bag-shaped hollow braid is formed, for example, using a circular knitting machine as described in the WO2005/020822a1 patent application. However, this is achieved by a special weaving head which will be described in more detail below with reference to the drawings. The process employed here is a specific process in which the shaped braid is bundled at the trailing end of its length (i.e., which will later become the distal end of the occluding device) while the leading end of the braid length (i.e., which will later become the proximal end of the occluding device) is closed. It is thus possible to manufacture a spherical or "bag-shaped" hollow braid, the end of which is bundled corresponding to the distal end of the finished occluder and the opposite closed end corresponding to the proximal end of the finished occluder. The finished occluding device exhibits mechanical properties in terms of e.g. expansion, stability, strength, etc., which can be routinely adapted for subsequent use of the occluding device. In a preferred manner, wires or even fine organic threads may be incorporated into the braid.

With regard to the method, the process steps of forming the stagnant regions and the rungs are preferably defined as process steps comprising shaping and heat treatment. This is particularly beneficial when the spherical hollow braid formed is made of nitinol or another material having shape memory properties or efficacy. For example, the occluder of the present invention is preferably defined by forming the braid from a shape memory polymer based on a polyanhydride matrix or hydroxy carboxylic acid. These polymers are synthetic degradable materials with thermally induced shape memory properties. Other shape memory polymers such as block copolymers are also contemplated. It is essential that such materials can be easily and simply brought into their applicable final shape using a combined shaping and heat treatment step. For example, the completed occluding device can be tapered to the size of the catheter. After leaving the catheter, the occluder can stretch itself and again assume the shape of the spherical hollow braid which is obtained by shaping the occluder during the manufacturing process in the shaping and heat treatment steps.

Preferably, when forming the spherical hollow braid, the spherical hollow braid is manufactured by winding fine wires or wires constituting the completed braid at a proximal end of the braid. This represents a conceivable and particularly simple method of producing the occluder according to the invention, whose proximal retention zone has a closed, flat-shaped proximal end (proximal face). Naturally, other manufacturing methods are also conceivable.

Drawings

In the following, preferred embodiments of the occluder of the present invention will be described in more detail with reference to the accompanying drawings, while a round knitting machine (round knitting machine) will also be described in detail to illustrate the method of manufacturing the occluder of the present invention by way of example. In the drawings:

figure 1 is a perspective view of an occluding device in an expanded state according to a first preferred embodiment of the present invention, wherein only the outline of the occluding device is depicted;

figure 2 is a perspective partial view of the distal retention zone of the occluding device of the first preferred embodiment shown in figure 1 in an expanded state;

figure 3 is a side view of the occluding device of the present invention shown in figure 2 in an expanded state;

figure 4 is a perspective view of a circular knitting machine illustrating the method of making the stopper of the present invention;

figure 5 is a top plan view of the circular knitting machine shown in figure 4 to illustrate the method of making a round ball, bulb or tear drop shaped initial (base) braid structure according to figures 9a to 9c, which can be used as the initial structure of an occluding device according to the present invention;

FIG. 6 is a partial view of a knitting head on the circular knitting machine depicted in FIG. 4;

FIG. 7 is an embodiment of a braid made using the braid head shown in FIG. 6, which may be used as the basic structure of an occluding device according to the present invention;

figure 8a is a side view of a special knitting head for making a round spherical, bulb-shaped or teardrop-shaped initial knit according to figures 9a to 9c, which can be used as a basic structure of an occluder according to the present invention;

figure 8b is a cross-sectional view of the weaving head according to figure 8 a;

FIG. 8c is a perspective view of a specialized knitting head for making a spherical knit;

figure 9a is a perspective view of the base of a spherical braid, which constitutes the starting body of the occluder of the present invention, wherein the base is shaped as close as possible to a round sphere;

fig. 9b is a perspective view of a base body of a spherical braid, which is suitable for producing the stopper according to the invention, wherein the base body is shaped to the greatest possible extent in the shape of a bulb;

figure 9c is a perspective view of a base of a spherical braid suitable for making an occluding device according to the present invention wherein the base is shaped as a tear drop;

figure 10a shows a spherical braid, which is used as a base body of different occluders according to the present invention, produced by a dedicated braiding method and having a distal anchor.

Figure 10b is a side sectional view of the right side of a PFO-type occluder of the present invention made of a spherical braid according to figure 9 a;

figure 10c is a side sectional view of the right side of an ASD type occluder of the present invention made from a spherical braid according to figure 9 a;

figure 11 is a side cross-sectional view of the right side of a PFO-type occluder of the present invention made from a balloon, bulb or tear-drop shaped initial braid structure according to figures 9 a-9 c and including a distal anchor;

figure 12 is a side cross-sectional view of the right side of a VSD style occluder of the present invention made from a round sphere, bulb or tear drop shaped initial braid structure according to figures 9 a-9 c and including a distal anchor;

figure 13 is a side cross-sectional view of the right side of an ASD-type occluder of the present invention made from a round ball, bulb or tear-drop shaped initial braid structure in accordance with figures 9 a-9 c and including a distal anchor;

figure 14 is a side cross-sectional view of the right side of a PDA type occluder of the present invention made from a round ball, bulb or tear-drop shaped initial braid structure in accordance with figures 9a to 9c and including a distal anchor;

figure 15a shows a tubular braid as disclosed in the prior art (e.g. according to us patent No.5,725,552) which constitutes the initial structure or matrix for the manufacture of the known occluding device, wherein each end of the tubular braid needs to be held in a separate holder;

figure 15b is a side sectional view of the right side of a PFO-type occluder of the prior art (e.g. according to U.S. publication No.5,725,552) made from a tubular braid according to figure 15 a;

figure 15c is a side sectional view of the right side of an ASD type occluder of the prior art (e.g. according to U.S. published patent No.5,725,552) made from a tubular braid according to figure 15 a;

figure 16a shows a tulip or bell shaped braid with a distal holder as disclosed in the prior art (e.g. WO2005/020822a 1);

figure 16b is a cross-sectional view of the right side of a PFO-type occluder of the prior art (e.g. WO2005/020822a 1) made of a tubular braid according to figure 16 a;

figure 16c is a cross-sectional view of the right side of an ASD type occluder of the prior art, such as disclosed in WO2005/020822a1, wherein the occluder is made of a tubular braid according to figure 16 a.

List of reference numerals:

1, a plugging device; 2, knitting; 3 a distal end;

4 thin wires, metal wires; 5a holder; 6a proximal retention zone;

7, knitting machine; 8a distal retention zone; 9 spools (spool);

10, a crosspiece; 11 a knitting head; 12 a proximal end;

13 spools (spool); 14, bolts; 15 forming a component;

16 impellers; 17 spool (bobbin) 18 cam plate;

Detailed Description

Fig. 1 shows a perspective view of an occluder 1 according to a first preferred embodiment of the present invention in an expanded state, the only contour of the occluder 1 being depicted in fig. 1. Figure 2 shows a perspective partial view of the distal retention area 8 of the occluder 1 of the first preferred embodiment shown in figure 1 in an expanded state. Figure 3 shows a side view of the occluder 1 of the present invention shown in figure 2 in an expanded state.

The occluder 1 consists essentially of a braid 2 formed of thin metal wires or threads 4, the thin wires or threads 4 preferably being made of nitinol or other shape memory material or material having a memory effect. The braid 2 exhibits sufficient flexibility to enable the occluding device 1 to be tapered to the diameter of a catheter (not explicitly shown) used in endovascular surgery. Because of the memory properties of the material, the tapered occluding device 1 also has a shape memory function, so that after release of the occluding device 1 from the catheter, the occluding device 1 will self-expand and will return to its predetermined shape corresponding to its use. This self-expansion usually ensues after the occluder 1, which is initially arranged in the catheter, has been positioned at the site to be treated.

As shown in particular in fig. 2 and 3, the occluder 1 has a proximal retention zone 6, a distal retention zone 8, and a cylindrical crosspiece 10 disposed between the proximal retention zone 6 and the distal retention zone 8 in the expanded state. The two retention zones 6, 8 are used to occlude defects or shunt channels in the septum. This blocking can ensue when the crosspiece 10 passes through the flow-dividing channel, because the stagnant zones 6, 8 are positioned on both sides of the flow-dividing channel to be blocked. The occluding device 1 according to the present invention thus represents an occluding system that can be introduced into a patient with a minimal invasive method (i.e., using a catheter or guidewire, for example) and positioned at a predetermined location.

The design of the occluder 1 of the present invention is therefore based on the principle of tapering the occluder 1 to the size of the catheter. After releasing the occluder 1 from the catheter, the retention zones 6, 8 then stretch themselves, so that the retention zones 6, 8 position themselves on both sides of the membrane. Furthermore, the design of the present invention makes the occluding device 1 a self-locating and self-centering system. Thus, to ensure that the stagnant regions 6, 8 are fixed to the septal wall, the rungs 10 should have the length of the atrial diaphragm, the septum, respectively.

Unlike the conventional occlusion systems disclosed in the prior art, which use a self-expanding umbrella as the proximal retention zone 6, the proximal retention zone 6 of the invention has a flat covering in the form of a proximal wall 112, which proximal wall 112 closes off the proximal end 12, so that no material of the implanted occluder 1 can penetrate the septum wall in the proximal region of the patient's organ anyway. Furthermore, the closed conformation of the proximal end 12 of the proximal retention zone 6 ensures that the edge of the proximal retention zone 6 is always flush with the membrane wall. Such a flush is achieved over a relatively wide area, regardless of the diameter of the defect or the thickness of the atrial diaphragm, the diaphragm respectively, allowing complete endothelialisation to take place relatively quickly after implantation of the occluder 1 and eliminating any possible reaction of defense mechanisms in the patient as blood is effectively prevented from coming into contact with the material of the implant 1.

The occluder 1 according to the present invention has a self-centering function in the shunt channel or defect because of the self-expanding nature of the implant 1 based on the memory properties of the materials used. The occluder 1 can also be withdrawn at any time before the occluder 1 is separated from the lead of the insertion device.

Based on the principles disclosed in the prior art, the occluder 1 according to the present invention may of course further comprise a fabric insert, which is not explicitly shown in the drawings. The fabric insert consists essentially of a polyester material. Chemically, dacron is a polyethylene terephthalate polyester that is obtained by the polycondensation of ethylene glycol and dimethyl terephthalate. Thus, in order to be able to completely occlude a defect or shunt passage in the septal wall, it is contemplated to incorporate a fabric insert into the interior of the rung 10 or onto the proximal end 12 of the retention zone 6. For example, a fabric insert may be incorporated by supporting it within the occluding device 1. The implant 1 inserted into the human body will then be completely enveloped by the tissues of the human body itself within a few weeks or months.

The braid 2 serves as the basic structure of the occluder 1 according to the present invention, the braid 2 being sufficiently rigid to grip and hold the fabric insert in place.

At the distal end 3 of the distal retention zone 8, the braid 2 converges into the anchor 5. This can be achieved by machining an internal thread (internal thread) in the holder 5, which can be used to engage a wire of an insertion device, not shown in the figures, when guiding the occluder 1 to a position in relation to the location of a septal defect, for example in endovascular surgery. After the occluding device 1 has been positioned within the shunt channel or defect, the engagement between the guidewire of the insertion device and the distal end 3 is then released. Of course, it is also conceivable to use a differently configured device instead of the internal thread in the holder 5 on the distal end 3.

As mentioned, fig. 1 shows a perspective view of a first preferred embodiment of an occluder 1 according to the present invention in an expanded state, while fig. 2 shows a perspective partial view of the distal retention area 8 of the occluder 1 of the first preferred embodiment shown in fig. 1. For the sake of simplicity, fig. 1 shows only the contour of the occluder 1. For further simplification, a detailed description of the braid 2 serving as a basic structure is omitted, and the shape of the occluder 1 is shown as a closed-face shape. The proximal retention zone 6 of the occluder 1 is flatter than in the first embodiment. Depending on the actual desired application, the proximal stagnant zone 6 may be formed into a more or less flattened shape to eventually form the proximal wall 112 in an expanded state. It is of course also conceivable to present the proximal wall 112 with a completely flat, spherical or approximately plate-shaped profile.

Fig. 4 is a perspective view of the circular knitting machine 7 shown for illustrating the method of manufacturing the stopper 1 according to the present invention. Figure 5 is a top plan view of the circular knitting machine 7 as shown in figure 4, depicted for elucidating the method of manufacturing the spherical, bulb-shaped or teardrop-shaped initial braid structure 2 according to figures 9a to 9c, which initial braid structure 2 can be used as the initial structure of the occluder 1 according to the present invention. Fig. 6 shows in more detail the knitting head 11 for the circular knitting machine 7 of fig. 4, while fig. 7 shows exemplarily a knitted fabric 2 manufactured using the knitting head 11 shown in fig. 6, which knitted fabric 2 can be used as a basic structure of the occluder 1 in accordance with the present invention. Fig. 8a is a side view of a special knitting head 11 for producing the round, bulb-shaped or tear-drop-shaped initial knit 2 according to fig. 9a to 9c, which initial knit 2 can likewise be used as a basic structure of the occluder 1 of the present invention. Fig. 8b further shows a cross-sectional view of the weaving head 11 according to fig. 8a, while fig. 8c depicts a perspective view of a special weaving head 11 for producing such a spherical braid.

In contrast to the known braiding method, in which all the threads or wires 4 are gathered together in a bundle at the front end of the braid 2 and extend to an extractor (extractor device), in the method according to the invention the material supply extends from every second bobbin 9 to the braiding head 11 and from the braiding head 11 to each subsequent respective bobbin 13 or to a plurality of separation gaps. The bobbin 13 without the supply of material only has auxiliary threads extending at least to the weaving head 11. The end of the supply of material is connected by means of a bolt 14 to the end of the auxiliary line closest to the auxiliary line spool.

The knitting head 11 is depicted in detail in the figures cited later, the knitting head 11 having a crown-shaped structure and being provided with forming elements 15, which forming elements 15 allow the thread or wire 4 to be hooked. The forming element 15 can be lowered to hook/unhook the fabric 2. The braiding head 11 is positioned axially over the center of the orbit of the impeller 16 so that the fine wire or wire 4 can be aligned at a straight downward angle to the spool 17 of the braiding machine 7.

After all the wires 4 required for the braid 2 have been connected and tightened, the braiding is started in a conventional known manner in which the impeller 16 is rotated about the centre while the bobbin 17 is switched from impeller to impeller so that the tracks of the impellers are crossed. The infeed (fed) of the braid 2 is achieved by a cam plate 18 which is rotated by an impeller 16. The length of the braid that can be produced in this way is proportional to the circumference and pitch (pitch) of the braid 2, as well as to the length of the wire and the end of the thin thread connected to the auxiliary thread. The resulting braid, with its free ends bundled or gathered, is then cut from the supply of material and unwound from the auxiliary thread. The hollow braid 2 thus produced is closed at the front end and bundled at the rear end in a round or bag shape. The wire bundle is gathered so that an internal thread for engaging a wire of an insertion device can be produced therein.

In a subsequent material-dependent shaping and heat treatment process, the braid 2 is formed into the desired shape of the occluder 1. Making the initial structure suitable for the manufacture of an occluder 1 for the treatment of a Patent Foramen Ovale (PFO), a Ventricular Septal Defect (VSD), an Atrial Septal Defect (ASD) or Patent Ductus Arteriosus (PDA).

At this point it is noted that, for example, figure 10b shows a cross-sectional side view of the right side of a PFO-type occluder 1 according to the present invention, in which the PFO-type occluder 1 is made of a spherical braid 2 as described before. Fig. 10c furthermore shows a side sectional view of the right side of an ASD occluder 1 according to the invention, wherein the ASD occluder 1 is likewise made from a spherical braid 2, which is produced as described above. In addition, figure 11 shows another side view of the PFO-type occluder 1 of the present invention.

It is further noted that fig. 12 discloses a side sectional view of the right side of a VSD occluder 1 according to the present invention, wherein the VSD occluder 1 is made of a round, bulb-shaped or teardrop-shaped initial braid 2 as described before. Finally, referring to fig. 13 and 14, fig. 13 and 14 depict cross-sectional views of the right side of the ASD-type and PDA-type occluders 1, respectively. The occluder of the present invention shown in figures 13 and 14 is made from a round ball, bulb or tear-drop shaped initial braid structure according to figures 9 a-9 c in sequence, wherein the initial braid is produced as described above.

Starting from the anchor 5 and depending on the configuration, an expanded diameter (i.e., distal retention zone 8) is formed, followed by the rung 10, and another expanded closed diameter (i.e., proximal retention zone 6, proximal wall 112, respectively) is connected to the rung 10.

Since some circumstances dictate that the braid 2 used as the base of the occluder 1 does not always completely occlude the defect itself, it is possible to introduce a fabric insert into the crosspiece 10 and the expanded diameter, the distal retention zone 8 and/or the proximal retention zone 6. These textile inserts, preferably of dacron, close the gaps remaining on the braid 2 when the occluder 1 is in the inserted state. For example, the fabric insert may be secured by stretching over the proximal opening like a cloth (cloth).

Referring again to fig. 6, fig. 6 depicts in more detail the knitting head 11 of the circular knitting machine 7 in fig. 4, while fig. 7 shows an embodiment of a knitted fabric 2 manufactured using the knitting head 11 shown in fig. 6, which knitted fabric 2 can be used as a basic structure of the occluder 1 in accordance with the present invention. It will be clear here that the braid 2, which serves as the basic structure of the occluder 1, is shaped as a tubular or bag-shaped braid, the top of which is closed, and only one anchor 5 has to be provided at its end 3, while the thread or wire 4 on its opposite side 12, for example, can be wound from the centre outwards.

The closed braid 2 can be shaped like a sphere (compare fig. 9a), a bulb (compare fig. 9b) or a teardrop (compare fig. 9c), wherein the distal end 3 is provided with only one internally threaded anchor 5, which anchor 5 is adapted to be snugly (snuggly) connected to an insertion catheter provided on the distal end 3.

As will be described below, important and very specific occluders 1 can be manufactured from a starting braid structure 2 in the shape of a sphere (fig. 9a), a bulb (fig. 9b) or a teardrop (fig. 9c), whereby the occluder 1 of the present invention can achieve substantially improved properties of function, in particular, for example, a very flat shape of the proximal wall 112, and no additional sealing of the proximal retention zone 6, respectively of the proximal wall 112 is required.

In particular, this is an occluder 1 for treating an Atrial Septal Defect (ASD), which is a hole in the atrial septum of the heart. Fig. 13 shows an embodiment of such an ASD occluder 1.

Furthermore, the occluder 1 may be produced for treating a Patent Foramen Ovale (PFO), i.e. for treating an oval opening/hole in the atrial septum of the heart. Figure 11 shows a PFO occluder 1 of this invention.

Furthermore, it is conceivable according to the invention to produce an occluder for the treatment of Patent Ductus Arteriosus (PDA), i.e. for the treatment of an open channel between the aorta and the pulmonary artery. Figure 14 depicts such a PDA occluding device 1.

Finally, it is also pointed out that an occluder 1 for the treatment of a Ventricular Septal Defect (VSD) according to the invention is also conceivable, namely for the treatment of a hole in the heart ventricle wall. Figure 12 shows an embodiment of such a VSD occluder.

Note this fact: the invention is not limited to the embodiments specifically shown in the drawings, but is instead susceptible to numerous modifications.

Claims (13)

1. An occluder comprising a holder (5) and a braid (2) of thin wires or threads (4), said braid (2) being formed into a suitable shape by a shaping and heat treatment process, having a proximal retention zone (6) and a distal retention zone (8), wherein the ends of said thin wires or threads (4) converge into the holder (5) on the distal retention zone (8), between said proximal retention zone (6) and distal retention zone (8) a cylindrical crosspiece (10) is arranged, wherein said two retention zones (6, 8) are typically positioned by endovascular surgery on both sides of a shunt channel to be occluded in a septum, while said crosspiece (10) traverses said shunt channel,

characterized in that the proximal retention zone (6) of the braid (2) has a completely closed proximal wall (112), which proximal wall (112) has a continuous surface on the proximal end (12) of the occluder, which continuous surface forms the proximal end (12) of the occluder.

2. The occlusion device of claim 1, wherein the continuous face of the proximal wall (112) is an arcuate face.

3. The occluder of claim 2, wherein the arcuate surface conforms to a surface of a portion of a spherical, bulb-shaped, or teardrop-shaped object.

4. The occluder of any preceding claim, wherein the braid (2) is comprised of nitinol or other material having shape memory or memory properties.

5. The occlusion device of claim 4, wherein the shape memory material is a biodegradable material.

6. The occluder of any preceding claim, wherein the braid (2) tapers to the diameter size of a catheter for endovascular surgery.

7. The occluder of claim 6, wherein the proximal retention zone (6) with the proximal wall (112) is arranged such that upon expansion of the occluder (1) the proximal wall (112) bends outwards, in such a way as to enter the septum wall in place.

8. The occluder of any preceding claim, wherein the distal retention zone (8) comprises a holder (5), which holder (5) is preferably arranged in the axial direction of the crosspiece.

9. The occluder of claim 8, wherein the distal retention zone (8) is further provided with at least one connecting element (16 '), wherein the connecting element (16') is engageable with a catheter.

10. The occluder of any preceding claim, wherein the occluder (1) is arranged to be reversibly collapsible and expandable, whereby the expanded occluder (1) can be collapsed using an explanted catheter and the press-fit connection between the proximal wall (112) and the septum wall can be released.

11. Method for manufacturing an occlusion device, in particular according to one of the preceding claims, wherein the method comprises the following process steps:

forming a hollow braid (2) of spherical, bulb or teardrop shape by a braiding process known per se, wherein said hollow braid (2) is bunched on a first distal end (3) and has a fully closed proximal wall (112) on an opposite second proximal end (12), the proximal wall (112) having a continuous face; and

forming a proximal stagnant zone (6) on a proximal wall (112), a distal stagnant zone (8) on a first end (3) of the bundle, and a cylindrical ledge (10) disposed between the proximal stagnant zone (6) and the distal stagnant zone (8).

12. The method according to claim 11, further comprising the process steps of: forming a retainer (5) on the distal end (3) of the bundle of hollow braids (2).

13. The method according to claim 11 or 12, wherein the process step of forming the stagnant zones (6, 8) and the rungs (10) comprises shaping and/or heat treatment.