DE19607451A1 - Occlusion implant for closing off arterial connections in humans or animals - Google Patents

Abstract

An occlusion implant (1) for closing off arterial connections in humans or animals, comprises a wire made of metal or plastic, which has shape memory characteristics, with a spiral shape in the form of a double cone. The wire (2) is surrounded by a secondary wire (6). The middle of the implant preferably has a nylon fibre (7).

Description

The present invention relates to an occlusion implant for closing arteriovenous short-circuit connections in the human or animal body, which is a wire made of metal or plastic with shape memory properties has, which is bent in the form of a double cone helix.

Arteriovenous short-circuit connections are mostly about congenital malformations of the human or animal body that become serious in the long term Damage to the affected body organs. One at Humans common form of arteriovenous Short circuit connection is a vascular connection between the Pulmonary artery (pulmonary artery) and the main artery (Aorta), the so-called ductus arteriosus botalli. This Vascular connection is present in all unborn children and usually becomes active after birth Contraction of the muscles in the wall of the duct and anatomical growth of the innermost layers of the vessels later locked. However, some children lack one sufficient contractility of the muscles in the Duct, so that the vascular connection is not or not is adequately closed. This has the consequence that on the one hand the blood supply to the body is reduced and  on the other hand the lung flow is increased. This leads to heart failure (heart failure). In the course of Years there is an increase in pressure in the Pulmonary flow path through changes in the pulmonary capillaries (pulmonary hypertension, Eisenmenger reaction) leading to Can lead to patient death.

According to the state of the art it is possible to use the duct arteriosus botalli through surgical procedures, drug Therapy or using catheter techniques too occlude an implant in the duct is introduced. As implants are, for example graft applied to a metal frame Polyvinyl alcohol (Ivalon) or a double umbrella known that folded into the interior of the body is introduced and released in the duct. This The disadvantage of implants is that they only work with relatively large caliber introductory sets with up to 9 mm (28 French) into the inside of the body can be introduced. Therefore they are not for him Suitable for use in newborns or premature babies where due to the large-caliber introductory cutlery Vascular lesion would be inevitable.

They are also state of the art Occlusal implants are known to have a metal wire or have plastic with shape memory properties, which is curved in the form of a double cone helix. Such Occlusion implants are stretched into the Introducer introduced and together with this in introduced the inside of the body. In the Arteriosus Botalli duct the occlusion implant is released from the catheter and takes on its predetermined spiral shape again. Of the Diameter of the turns of such occlusion implants is chosen slightly larger than the diameter of the duct, so that  the occlusion implant is somewhat narrowed radially and elastic restoring forces of the windings against the Press the vessel wall of the duct and the implant there anchor. Due to the possibility of changing the diameter of the Occlusion implant for insertion into the interior of the body downsize it by stretching it into the Introducer can be inserted Introducer with relatively small widths of 1.5 mm (4-5 French) can be used. These can also be used for Newborns or toddlers can be used without Causing vascular lesions.

However, the thin wire material has only a small one Surface, with the result that the individual turns due to the elastic restoring forces in the Press in the vessel wall of the duct and there to a Damage to the intima. Furthermore act through the blood flow in the ductus arteriosus botalli relatively large axial flow forces on the Occlusion implant, so that there is a risk that the individual turns are pushed axially into each other. In in this case the entire occlusion implant becomes one irregular balls with an unpredictable structure, its secure anchoring to the vessel wall of the duct is uncertain and of embolism or other complications can lead.

It is also known in the prior art that biconical shape memory wire one Wrap occlusion implants in a thread. On Occlusion implant from such a wound Shape memory wire has much larger surfaces on and can accordingly with larger support surfaces on the vascular wall of the ductus arteriosus botalli support. Furthermore there is the thread-shaped winding  of the shape memory wire the turns of the Double cone helix a greater spatial abundance causes the occlusion implant except through the elastic restoring forces by yourself pinching effect is anchored in the duct. In fact become axial due to the blood flow in the duct flow forces acting on the occlusion implant the mutually supporting turns of the cone in deflected radially outward supporting forces. More accurate the individual turns are said by the Flow forces pressed against each other, each turn of an adjacent turn with a smaller diameter radially is pushed outwards against the wall of the duct. The prerequisite for this self-pinching effect is however, that the individual turns of the cone so have great spatial abundance that the one another can support the following turns against each other.

The well-known, self-winding However, double cone coils have the disadvantage that the individual turns have only a low dimensional stability. Already small, radially from the outside on the turns Forces acting bring the windings out of their originally circular shape. The low dimensional stability is particularly important for occlusion implants with larger Diameter over 2.5 mm disadvantageous because of the desired self-pinching effect is no longer easy sets. The individual pressed against each other, unstable turns are caused by the axial flow force namely not only pushed radially outwards, but dodge it inside, so that the unwanted tangles explained above results.

It is therefore an object of the invention To create an occlusion implant of the type mentioned at the beginning,  that avoids the disadvantages mentioned, especially one safe occlusion also relatively more arteriovenous Short-circuit connections permitted and with one for Introductory set suitable for newborns and toddlers can be introduced.

The invention relates to an occlusion implant for Closing arteriovenous short-circuit connections in the human or animal body, which is a wire made of metal or plastic with shape memory properties which is bent in the form of a double-cone spiral, the shape memory wire with a secondary wire is wrapped in a thread.

In the occlusion implant according to the invention, the Shape memory wire primarily the function that Double cone helix the required dimensional stability give. The thread-shaped around the shape memory wire In contrast, wound secondary wire has the function of Turns of the double cone to a greater spatial abundance give them better on the walls of the duct can support. Because of the state of the art greater dimensional stability on the one hand and the large spatial Abundance of turns, on the other hand, also becomes apparent Large diameter occlusion implants with large Security the desired self-pinching effect. In all of this, the occlusion implant is in accordance with the invention nevertheless with an introductory set of very small caliber, e.g. B. 1 mm (2-3 French) insertable and therefore for Suitable for newborns and toddlers.

With the occlusion implant according to the invention, very wide arteriovenous short circuit connections safe anatomically close. Also closing a duct arteriosus botalli with a typically very high  There is blood flow and no significant restrictions possible without any problems. This means that patients in particular for whom a duct closure is urgently necessary because of the Blood flow through the duct is very high and therefore significant damage to the organs involved is evoked, now for the first time with a double cone-shaped occlusion implant are treated can.

After inserting the occlusion implant into the Ductus accelerates thrombus formation Invention before that the secondary wire from a thrombogenic Material exists. Due to thrombus formation it comes rapid growth of the occlusion implant into the Intima of the duct and its final anatomical Closure. Rapid thrombus formation is important to the Patients as soon as possible from his complaints free and further damage to the affected To avoid body organs. As thrombogenic materials platinum or gold alloys are used, for example Commitment. The one bent in the form of a double cone helix Shape memory wire of the occlusion implant persists as before from a material with shape memory properties made of metal or plastic and gives the individual turns of the occlusion implant the high dimensional stability. By the Structure of the occlusion implant from two different ones Wires, the wire materials can be chosen so that them to the particular task of the wire, dimensional stability or thrombogenicity, are optimally matched.

To display the occlusion implant using a imaging method using X-rays enable, the invention proposes that the Secondary wire consists of an X-ray opaque material. This allows the entire insertion process of the  Occlusal implant and its exposure inside the body Area of the arteriovenous short circuit connection over a X-ray imaging method follow. This ensures precise positioning of the occlusion implant at a desired location in the Body interior. When checking the Duct closure can be opened again by a X-ray imaging method Effectiveness of the introduced occlusion implant check. X-ray opaque materials have been particularly proven platinum and gold alloys.

A preferred embodiment of the invention provides that at the distal end of the occlusion implant Shape memory wire and the secondary wire unsolvable are interconnected. This will cause a move the shape memory wire and the secondary wire relative to each other prevented. The occlusion implant retains during the insertion process and also in the duct Construction at. This is for an intended function of the occlusion implant is essential. The distal end of the Occlusion implant leaves during the insertion process first the introductory set and also the first pushed into the duct. It must be ensured that the shape memory wire and the secondary wire on the distal Don't end up in the introductory set or in the Hook the wall of the vessel. This would be a proper one Prevent and close positioning of the occlusion implant Damage to the duct. Through the inventive connection of the shape memory wire with the secondary wire at the distal end of the occlusion implant its smooth exit from the Introducer and introducer into the duct guaranteed.  

A particularly advantageous embodiment of the invention provides that at the proximal end of the Occlusal implant, especially a spherical one Fastener is arranged. To introduce the Occlusal implant inside the body will be in the stretched condition drawn into a catheter. To do this engages in the distal end of a sliding link in the Catheter arranged gripping mechanism the spherical Fastener and pulls the occlusion implant Lengthways into the catheter. Then the catheter is put together with the occlusion implant in it Body introduced and to the arteriovenous Short-circuit connection moved. There is the sliding backdrop with the occlusion implant out of the catheter. Due to the pseudoelastic properties of the It takes away the wire material inside him again previously imposed shape of a double cone helix. The occlusion implant is after Pushing out of the catheter in an optimal position, so it is opened mechanically by opening the gripping mechanism solved the sliding gate of the catheter. Is the location of the Occlusal implant, however, still needs improvement, see above it can be wholly or partially pulled back into the catheter and repositioned. This enables optimal Positioning and secure anchoring of the Occlusion implant in the duct and a quick, easy growth of the duct. Of course you can the fastener any three-dimensional shape have, but in practice it has a spherical shape trained fastener due to its Symmetry properties particularly proven.

Another embodiment of the invention provides that in the middle part of the occlusion implant, in which the meet both cones face to face, radially towards  external threads made of surgical nylon material are arranged like a brush. In addition to the thrombogenic material properties of the secondary wire it the threads promote thrombus formation in the area of the Occlusion implant after insertion in the duct. It there is a rapid anatomical closure of the Duct, the patient is relieved of his symptoms and further damage to the affected body organs avoided.

An embodiment of the invention is as follows explained in more detail with reference to the drawings. Show it:

Fig. 1 shows an inventive Okklusionsimplantat in side view;

FIG. 2 shows section II of the occlusion implant according to the invention from FIG. 1;

Fig. 3 is a section along the line III-III in the direction of arrows of the Okklusionsimplantats invention in FIG. 1.

In the following description of the drawings are for same components used matching reference numerals.

An occlusion implant according to the invention is identified as a whole in FIG. 1 by reference number 1 . The outer shape of the occlusion implant 1 is characterized by a shape memory wire 2 bent in the form of a double-cone helix. The shape of the double cone helix is determined by a first cone 3 and a second cone 4 , which are connected to one another at the end by a central part 5 . The two cones 3 , 4 and the central part 5 are bent in one piece from the shape memory wire 2 . The shape memory wire 2 consists of a biocompatible, pseudo-elastic nickel-titanium wire. It is wrapped in a thread shape over its entire length with a thrombogenic, X-ray opaque secondary wire 6 made of a platinum alloy. In order to accelerate thrombus formation after insertion of the occlusion implant 1 in an arteriovenous short-circuit connection in the human body, threads 7 made of surgical nylon material are arranged in a brush-like manner on the central part 5 of the occlusion implant 1 . At the distal end 1a of the Okklusionsim plantats 1 of the shape memory wire 2 is permanently connected with the secondary wire 6 to a displacement of the two wires 2, 6 to prevent against each other and in order during insertion of the Okklusionsimplantats 1 snagging of the shape memory wire 2 or the secondary wire 6 in Prevent catheter or in the vascular wall of the duct.

In Fig. 2 of the detail II of FIG's. 1 enlarged. It can clearly be seen that the shape-memory wire 2 is wound in a thread-like manner by the secondary wire 6 . At the proximal end 1 b of the occlusion implant 1 , a spherical fastening element 8 is introduced to the shape memory wire 2 . To insert the occlusion implant 1 into the interior of the body, it is drawn into a catheter, not shown, in the stretched state. The inside of the catheter has a sliding link with a gripping mechanism at its distal end. The gripping mechanism engages around the spherical fastening element 8 and the sliding link is withdrawn with the occlusion implant 1 into the catheter. The catheter with the occlusion implant 1 located therein is then inserted into the interior of the body and positioned in the area of the arteriovenous short-circuit connection. There, the sliding link together with the occlusion implant 1 is moved out of the catheter. Immediately after leaving the catheter, the occlusion implant 1 again assumes the shape of a double-cone helix imposed on it due to the pseudo-elastic properties of the wire material. If the occlusion implant 1 is in an optimal position after being pushed out of the catheter, it is mechanically detached from the sliding link by the gripping mechanism releasing the spherical fastening element 8 . In the event of insufficient positioning of the occlusion implant 1 in the arteriovenous short-circuit connection, the occlusion implant 1 can be withdrawn into the catheter at any time and repositioned.

FIG. 3 shows the occlusion implant 1 according to the invention in a section along the line III-III from FIG. 1 in the direction of the arrows. The central middle part 5 can be seen, which is surrounded by the windings 10 of the shape memory wire 2 in the region of the first cone 3 . For the purpose of better clarity, the threads 7 are not shown in FIG. 3. After exposure of the occlusion implant 1 in the arteriovenous short-circuit connection, the aim is to regain the shape of a double-cone helix originally imposed on it. The maximum diameter of the turns 10 of the occlusion implant 1 is chosen to be somewhat larger than the diameter of the short-circuit connection, so that the turns 10 of the shape memory wire 2 press against the innermost layers of the vessel of the short-circuit connection. Only through the use of the supporting shape memory wire 2 are these radially outward elastic restoring forces so great that a secure fixation of the occlusion implant 1 in the arteriovenous short-circuit connection is ensured. An additional anchoring of the occlusion implant 1 occurs due to the self-pinching effect. The flow of blood in the arteriovenous short-circuit connection exerts axial flow forces in the direction 9 on the occlusion implant 1 . The individual windings 10 of the first cone 3 are thereby pressed against one another and in each case are pressed radially outwards against the vessel wall of the short-circuit connection by an adjacent winding 10 with a smaller diameter. The greater the blood flow and thus the axial flow forces are, the stronger the occlusion implant 1 is anchored in the short-circuit connection by the radial supporting forces. For the deflection of the axial flow forces into a radially outward supporting force, sufficient stability is required on the one hand and sufficient spatial abundance of the individual turns 10 of the occlusion implant 1 on the other hand. This stability is ensured by the shape memory wire 2 ; the spatial abundance results from the secondary wire 6 . The interaction of the wires 2 and 6 enables a uniform, controlled and predictable development of the radially outward supporting forces.

Claims (6)

1. occlusion implant ( 1 ) for closing arteriovenous short-circuit connections in the human or animal body, which has a wire made of metal or plastic with shape memory properties, which is bent in the form of a double-cone helix, characterized in that the shape memory wire ( 2 ) with a secondary wire ( 6 ) is wrapped in a thread. 2. occlusion implant ( 1 ) according to claim 1, characterized in that the secondary wire ( 6 ) consists of a thrombogenic material. 3. occlusion implant ( 1 ) according to claim 1 or 2, characterized in that the secondary wire ( 6 ) consists of an X-ray opaque material. 4. occlusion implant ( 1 ) according to one or more of claims 1 to 3, characterized in that at its distal end ( 1 a) the shape memory wire ( 2 ) and the secondary wire ( 6 ) are inextricably linked. 5. occlusion implant ( 1 ) according to one or more of claims 1 to 4, characterized in that a particularly spherical fastening element ( 8 ) is arranged at its proximal end ( 1 b). 6. occlusion implant ( 1 ) according to one or more of claims 1 to 5, characterized in that in the central part ( 5 ) of the occlusion implant ( 1 ), in which the two cones ( 3 , 4 ) meet on the end face, extending radially outward Threads ( 7 ) made of surgical nylon material are arranged in a brush-like manner.