WO2012038522A1

WO2012038522A1 - Feed system for medical functional elements

Info

Publication number: WO2012038522A1
Application number: PCT/EP2011/066556
Authority: WO
Inventors: Frank Nagl
Original assignee: Acandis Gmbh & Co. Kg
Priority date: 2010-09-23
Filing date: 2011-09-23
Publication date: 2012-03-29
Also published as: DE102010046408A1; DE102010046408B4

Abstract

The invention relates to a feed system for medical functional elements, comprising a catheter (10) and a medical functional element (11) having a compressible and expandable, rotationally symmetrical lattice structure (12), which in the compressed state is movably arranged in the catheter (10) in order to release the functional element (11) out of the catheter (10) by means of a relative movement between the catheter (10) and the functional element (11) and to expand same, wherein a recuperating mechanism is provided so as to pull the released functional element (11) back into the catheter (10). The invention is characterized in that the recuperating mechanism comprises a flexible coupling element (14) having at least one helically arranged wire thread (13), the distal end (13a) of which is rigidly connected to a proximal end (12a) of the lattice structure (12) and the proximal end (13b) of which is detachably connected to an actuating element for pulling back the released functional element (11) in the catheter (10) such that, as a result of a relative movement of the wire thread (13) with respect to the catheter (10), a recuperating force can act on the functional element (10), wherein the coupling element (12) that has been fully released from the catheter (10) can be expanded such that the cross-sectional diameter of the expanded coupling element (14) corresponds to, or is greater than, the cross-sectional diameter of the expanded lattice structure (12).

Description

Delivery system for medical functional elements

Such a delivery system is known for example from EP 1 374 801 AI, which shows a delivery system with a catheter in which a guide wire is arranged longitudinally displaceable. The guidewire includes at its distal end a plurality of coil-like elements supporting a stent. Concretely, the stent is arranged between two outer coil-like elements, wherein the outer coil-like elements almost completely fill the inner diameter of the catheter.

To then implant the stent, the delivery system, in particular the catheter tip, is guided to the treatment site. The treatment site may be, for example, a stenosis or an aneurysm. Subsequently, the catheter is moved relative to the guide wire so that the distal end of the stent is released. The distal end of the stent expands and attaches to the vessel wall. The expansion or expansion of the stent extends from distal to proximal with further proximal movement of the catheter.

In practice, it has proven to be expedient to partially release the stent initially during the implantation of the stent. Specifically, during implantation of the stent, the proximal end of the stent is held within the catheter as long as possible. This makes it possible to retract the stent into the delivery system or the catheter, if there is an undesirable change in position of the distal end of the stent. For example, the stent can be released from the catheter approximately to the extent that 70% to 80% of the stent is arranged outside the catheter with respect to the stent length. In this way, on the one hand, the correct position of the stent can be controlled and, on the other hand, the influence of the blood flow or pulse beat on the position of the stent can be observed.

If a change in the stent position, ie a repositioning, is required, the catheter can be pushed over the stent in the distal direction, whereby the already expanded part of the stent is returned to the compressed state. was transferred. The implantation position can then be corrected and the stent released again.

The exact positioning of the stent with the known delivery system requires a high degree of sensitivity of the user, since even a small movement of the catheter in the distal direction can lead to complete discharge of the stent. A repositioning is then no longer possible. In other words, there is the risk in the known delivery system that the stent is used quickly and uncontrollably. This is all the more true, as the operation of the guide wire or the operation of the relative movement between the catheter and guidewire outside of the body, so relatively far away from the treatment site takes place. Since both the catheter material and the guide wire have elastic properties, movement at the proximal end of the catheter or guidewire has a different effect on the relative movement on the catheter tip, so that precise control of the release process is not possible.

Moreover, stents have the property of shortening in expansion. The stent length is thus dependent on the degree of expansion or on the expanded diameter of the stent. For the known delivery system, this means that with complete release of the stent, ie upon release of the proximal stent end from the catheter, a change in position of the stent can occur, which can not be reversed.

The invention is based on the object of specifying a delivery system for medical functional elements, which enables improved handling and offers increased positioning accuracy for the functional elements. In particular, a delivery system is to be provided with the invention, with which it is possible to estimate the conditions during implantation, in particular the positioning with respect to the treatment site, the functional elements improved with the option to reposition the functional element.

According to the invention, this object is achieved by the subject matter of patent claim 1. The invention is based on the idea of specifying a delivery system for medical functional elements, which comprises a catheter and a medical functional element with a compressible and expandable, rotationally symmetrical lattice structure. The grid structure is arranged displaceably in the catheter in the compressed state in order to discharge and expand the functional element from the catheter by means of a relative movement between the catheter and the functional element. In this case, a return mechanism is provided to withdraw the discharged functional element in the catheter. The return mechanism has a flexible coupling element with at least one spirally arranged wire thread. The distal end of the wire thread is fixedly connected to a proximal end of the lattice structure. The proximal end of the wire thread is releasably connected to retract the discharged functional element in the catheter with an actuating element such that the functional element can be acted upon by a relative movement of the wire thread relative to the catheter with a return force. The coupling element completely released from the catheter is further expandable such that the cross-sectional diameter of the expanded coupling element is equal to or greater than the cross-sectional diameter of the expanded lattice structure.

In the context of the present application, the medical direction indications "distal" and "proximal" are based on the user of the medical device as a reference point. Distally arranged elements or areas are therefore further away from the user of the medical device than proximally arranged elements or areas.

The invention is thus based on the idea of providing a return mechanism between the completely discharged functional element and the catheter, which comprises a flexible coupling element. This ensures that with complete expansion of the functional element, for example in a blood vessel, a connection between the functional element and the catheter, so that the functional element is retractable into the catheter. The location and the behavior of the fully expanded functional element can thus be controlled and adjusted if necessary. Since the functional element is still connected to the catheter, a repositioning of the functional element is possible. In this case, the coupling element is preferably formed so flexible that the coupling element, the expansion of the functional element in Essentially not influenced. The coupling element is detachably connected at its proximal end to an actuating element. The releasable connection allows release of the coupling element as soon as the final, correct position of the functional element is set. Upon complete release of the coupling element, the coupling element expands and assumes substantially the same cross-sectional dimension as the expanded functional element. The expanded coupling element can thus remain in the body together with the functional element. The coupling element is preferably adapted such that the coupling element in the implanted state, that is, upon complete release from the catheter, rests against the vessel wall of the body vessel. In the implanted state or fully discharged state, the coupling element essentially assumes the cross-sectional diameter of the body vessel. The fully expanded coupling element is aligned with the functional element.

The functional element exerts a radial force on the vessel wall, for example when used as a stent in a blood vessel. Likewise, the expanded, fully released coupling element causes a radial force on the vessel wall. The radial force of the coupling element is preferably smaller than the radial force of the functional element. The combination of the functional element with the coupling element thus additionally enables an improved introduction of force into the vessel wall. Specifically, the coupling element with the relatively lower radial force provides a smooth transition from the free vessel wall to the vessel wall portion supported by the functional element.

In general, the coupling element and the functional element can exert different radial forces on the vessel wall. On the one hand, the coupling element, as explained above, have a lower radial force than the functional element. On the other hand, the radial force of the coupling element may be equal to or greater than the radial force of the functional element. In the latter case, the coupling element can contribute to avoiding a so-called cigar shape of the functional element. The functional element per se can have the disadvantage of not being able to expand completely at the axial ends, so that the cross-sectional diameter of the axial ends of the functional element is smaller than the cross-sectional diameter of a middle section of the functional element. Thus, a cigar-like shape of the functional adjust. By means of the coupling element, which has an equal or greater radial force than the functional element, it can be achieved that at least one axial end, in particular the proximal end, of the functional element widens completely so that the functional element as a whole forms a cylinder-like structure. Advantageously, it can be provided to arrange a coupling element at both axial ends of the functional element, wherein a distally arranged coupling element does not necessarily have to have a connection to an actuating element arranged within the catheter. The distally disposed coupling element is rather free. In particular, the distal coupling element can form an expansion element, wherein the structure of the expansion element corresponds to the structure of the proximal coupling element.

A coupling element with a higher radial force than the functional element has the advantage that the edge regions of the fully expanded functional element are pressed more strongly into the vessel wall. Thus, the fixation of the functional element can be improved at least at one axial end. The higher radial force of the coupling element is in a free state of the overall system, ie in an expanded state outside the body vessel, characterized in that the coupling element in the fully expanded state may have a larger cross-sectional diameter than the functional element. The difference between the cross-sectional dimensions of the coupling element and the functional element is substantially balanced in the implanted state by the body vessel, so that the coupling element in the implanted state is aligned with the functional element, wherein the coupling element exerts a greater radial force on the vessel wall. The different radial forces or expansion diameter of the coupling element and the functional element can be achieved, for example, by different braiding angles. Alternatively, the thickness of the wire elements may be different to set different radial forces. Suitable measures are known to the person skilled in the art.

Since the outer diameter of the expanded coupling element substantially corresponds to the outer diameter of the expanded lattice structure in the implanted state or the inner diameter of a body vessel to be treated, the function of the functional element is not impaired. In particular, will a blood flow through a body vessel is not affected by the coupling element.

In a preferred embodiment of the delivery system according to the invention, the wire thread has an impressed spiral shape in such a way that the wire thread spirals up after release from the catheter. In other words, the wire thread may have a helical spring-like shape, wherein the wire thread is in an elongated state within the catheter. During expansion, the wire thread resumes the original spiral shape and thus stretches spirally in a body vessel. The spiral shape allows a simple automatic and space-saving arrangement of the wire thread and the coupling element in the expanded state. In particular, the spiral shape allows a particularly simple approach of the shape of the expanded coupling element to the shape of the expanded functional element.

The distal end of the wire thread may be attached to a tip of a proximal marginal cell of the grid structure. Preferably, the lattice structure comprises cells, wherein the cells forming the proximal end of the lattice structure are referred to as marginal cells. The edge cells may, for example, have a diamond-like shape. The proximal end of the lattice structure is bounded by apices of the proximal marginal cells. The tips of the proximal marginal cells preferably point in the proximal direction. The connection of the wire thread with a tip of a proximal edge cell is particularly easy to produce and allows easy compression of the fully released functional element.

The coupling element may comprise a plurality of wire strands each attached to a tip of a proximal marginal cell of the grid structure such that the coupling element is connected to all of the tips of the proximal marginal cells. The stability of the connection between the coupling element and the functional element is increased in this way. Furthermore, the repositionability of the functional element is improved, since the functional element is comparatively easily compressible by the connection of the coupling element with all the tips of the edge cells of the lattice structure in order to be withdrawn into the catheter. In particular, it is avoided by the connection of the coupling element with all the tips or all free ends of the functional element that Retracting the functional element in the catheter open ends of the functional element consist, which can get caught and thus block a retraction of the functional element. Thus, by the connection of all the tips with the coupling element damage to the functional element or a violation of the vessel wall is avoided. For a complete repositionability or a complete retraction or removal of the functional element after complete expansion within a body vessel, therefore, the connection of the coupling element with all the tips or free ends of the functional element is particularly advantageous.

The invention is explained in more detail below on the basis of exemplary embodiments with reference to the accompanying schematic drawings. 1 shows a side view of a delivery system according to the invention in accordance with a preferred embodiment, wherein a fully expanded functional element is connected to a catheter of the delivery system by a flexible coupling element; a side view of the delivery system of Figure 1, wherein the coupling element is completely discharged;

Figures 3a-3c: each a side view of a feed system according to the invention according to a further preferred embodiment in different stages of the discharge of the functional element.

FIG. 1 shows a delivery system for medical functional elements 11 which comprises a catheter 10 and a medical functional element 11. The medical functional element 11 may be a medical implant or a prosthesis. In particular, the functional element 11 may be a stent, a blood filter, a thrombosis scavenger or thrombectomy device, a vascular prosthesis or another medical implant comprising a compressible and expandable, rotationally symmetric lattice structure 12. In the exemplary embodiments illustrated in FIGS. 1 and 2, the functional element 11 is designed as a stent.

The stent or generally the functional element 11 is compressible and expandable. Concretely, the functional element 11 can be converted from a compressed state to an expanded state and vice versa. Preferably, the functional element 11 is rotationally symmetrical and comprises a grid structure 12.

The lattice structure 12 can be made of a solid material by a material-removing process. In particular, the lattice structure 12 can be produced by laser cutting from a flat or tubular base body. When using a flat base body, it is preferred if the cut lattice structure 12 is then converted into a tubular shape. The grating structure 12 may also be made by a sputtering etching process. On the one hand, the lattice structure 12 can be formed in its rotationally symmetrical shape by the putter etching method. On the other hand, a flat lattice structure can first be produced by the sputter etching process, which is then converted into the tube shape.

The sputter etching method may include etching steps applied to a substrate. In a subsequent method step, the material of the lattice structure 12 can be applied to the etched substrate by sputtering or generally by a physical deposition method, so that the lattice structure 12 is formed directly or the ridges of the lattice structure 12 are formed directly. Alternatively, first a material layer can be sputtered, which is subsequently treated by etching, so that the lattice structure 12 is formed, wherein the openings of the lattice structure 12 are exposed by the etching. The sputter etching method has the advantage that special structural properties of the lattice structure can be set, which can have an advantageous effect on the functioning of the functional element 11 or coupling element 14.

In lattice structures 12 made by laser cutting or a sputter etching process, it is advantageous to provide at the axial ends of the lattice structure 11 or the functional element 11 to provide structures that serve as X-ray markers. Such X-ray marker structures or elements may have larger dimensions than the components of the remaining grid structure 12. X-ray marker elements are preferably arranged on tips 16 of the axial ends of the grid structure 12. The x-ray markers at the tips 16 are advantageously connected to the coupling element 14, in particular wire threads 13 of the coupling element 14. The coupling element 14 may help to apply the x-ray marker elements in the implanted state to a vessel wall. For this purpose, the coupling element 14, for example, have a greater radial force than the functional element 11.

Alternatively, the grid structure 12 may comprise a wire mesh. In this case, a plurality of spirally wound around a common axis of rotation wires may be provided, wherein the wires are partially guided in different directions of rotation about the axis of rotation. The wires cross each other at crossing points. The wires can cross over and cross each other alternately in adjacent crossing points, so that a meshwork results. Different braiding variants are conceivable. For example, a first wire element may cross over an opposite, second wire element at each second crossing point and intersect at the intermediate point of intersection. Such a braid is called 1-over-1 braiding. Alternatively, a first wire element may intersect an opposing second wire element at every third intersection, the wire element intersecting the opposing wire element in the two intermediate points of intersection. Such a braid is called 2-over-1 braiding. In further variants, for example, a 2-over-2 weave, an I-over-2 weave, an I-over-3 weave, a 2-over-3 weave, a 3-over-3 weave, or similarly varied braids may be provided.

It is also possible to make the wire mesh of the lattice structure 12 of the functional element 11 such that at least two, in particular several, in particular all, wires of the lattice structure 12 can be combined at the proximal end of the functional element 11 to one or more wire ends. In this case, the summarization of the wire ends by means of twisting, braiding, crimping, gluing, welding, soldering or other connection techniques. Preferably, all the wires of the lattice structure 12 are to a single rounded end or form a single combined wire end, which is connected to the coupling element 14. In the expanded state of the functional element 11, a sloping proximal end 12a or a combined wire end can thus be formed. Such a shape of the proximal end 12a of the lattice structure 12 is described, for example, in German Patent Application No. 10 2009 056 450, which is based on the Applicant. When using such a grating structure 12 for the functional element 11, for example, a coupling element 14 may be provided which comprises a single spirally wound wire thread 13. It is not excluded that the coupling element 14 has a plurality of wire threads 13.

The lattice structure 12 or, more generally, the functional element 11 is arranged displaceably in the catheter 10, wherein the lattice structure 12 is present within the catheter in the compressed state. The inner diameter of the catheter 10 causes the functional element 11 or the lattice structure 12 to remain in the compressed state. In general, the lattice structure 12 or the functional element 11 can be self-expandable. For example, the lattice structure 12 may include a shape memory material that causes the lattice structure to expand or expand automatically upon release from the catheter 10. Preferred materials are, for example, nickel-titanium alloys or shape memory polymers.

The displaceable arrangement of the lattice structure 12 in the catheter 10 makes it possible for the functional element 11 to be released from the catheter 10 by a relative movement between the catheter 10 and the functional element 11. The release of the functional element 11 thus takes place via a relative movement between the functional element 11 and the catheter 10. Concretely, the functional element 11 is coupled to an actuating element (not shown) which can be operated by a user. The actuating element can be moved relative to the catheter 10 so that the relative movement between the functional element 11 and the catheter 10 is established. For example, the actuating element may comprise a guide wire, which is movable at the proximal end, ie outside the body to be treated, separated from the catheter 10 by a user. Thus, the relative movement between the functional element 11 and the catheter 10 can be controlled by the user outside. The delivery system further comprises a return mechanism that causes the at least partially released, in particular completely discharged, functional element 11 to retract into the catheter. The return mechanism comprises a flexible coupling element 14 which is arranged between the functional element 11 and the actuating element. Specifically, the coupling element 14 connects the functional element 11 with the actuating element. The coupling element 14 is firmly connected to the functional element 11. There is a releasable connection between the coupling element 14 and the actuating element. The releasable connection between the coupling element 14 and the actuating element can be effected for example by an undercut. In general, therefore, the coupling element 14 may be positively connected to the actuating element, wherein the positive connection can be released automatically with complete release of the coupling element 14 from the catheter. Alternatively, the connection between the coupling element 14 and the actuating element can be actively detachable, for example by a rotary movement of the actuating element. Other releasable connection mechanisms are possible. The coupling element 14 may also be frictionally connected to the actuating element. The frictional connection can be released automatically after discharge from the catheter.

Specifically, the coupling element 14 has at least one spirally arranged wire thread 13. It is also possible that the coupling element comprises a plurality of wire threads 13, for example five wire threads 13, as shown in FIG. With more than one wire thread 13 it can be provided that the wire threads each form opposite spirals. The wire threads 13 are preferably spirally wound in the same direction of rotation (FIG. 1).

The spirally arranged wire thread 13 or the plurality of spirally arranged wire threads 13 each have a distal end 13 a, which is fixedly connected to a proximal end 12 a of the lattice structure 12. In particular, the distal end 13a of the wire thread 13 can be welded, glued or formed in one piece with the proximal end 12a of the lattice structure 12.

The wire thread 13 further has a proximal end 13b, which is releasably connected to the actuating element. The length of the wire thread 13 is preferred adapted such that the length of the coupling element 14, so the distance between the proximal end 12a of the grid structure 12 to the catheter 10 at least the simple, in particular at least twice, expanded cross-sectional diameter of the functional element 11 corresponds. The length of the coupling element 14 may also correspond to at least three times, in particular at least four times, expanded cross-sectional diameter of the functional element 11.

It is advantageously provided that the connection between the coupling element 14 and the lattice structure 12 is effected by the connection of the distal end 13a of the wire thread 13 with a tip 16 of an edge cell 15a of the lattice structure 12. In other words, the lattice structure 12 has cells 15 which are delimited by webs 17 of the lattice structure 12. At the axial ends of the lattice structure 12 or in the edge regions of the lattice structure 12, the cells 15 form edge cells 15a. The edge cells 15a are diamond-shaped and have three corners, which are each connected to a further cell 15 through a crossing point 18 of the webs 17. A fourth corner of the peripheral cell 15a forms a free tip 16. The tips 16 of all edge cells 15a bound the lattice structure 12 in the axial direction or define the proximal end 12a of the lattice structure 12. The wire thread 13 or concretely the distal end 13a of the wire thread 13 is preferably firmly connected to the tip 16 of the peripheral cell 15a. It is particularly preferred if the coupling element 14 comprises a plurality of wire threads 13, which are each connected to a tip 16. Preferably, all the tips 16 are firmly connected to a wire thread 13.

The coupling element 14 has self-expandable properties essentially analogously to the functional element 11. The self-expandable properties of the coupling element 14 may on the one hand be effected by a spring-like force component, which results from the spiral shape of the wire threads 13. Alternatively or additionally, the self-expandable properties can be effected by the material of the wire threads 13. For example, the wire strands 13 may comprise a shape memory metal or a shape memory polymer. In particular, the wire thread 13 may comprise a nickel-titanium alloy. The wire thread 13 may be connected to the functional element 11 by crimping, gluing, welding, knotting or a positive connection. This applies both to wire threads 13, which comprise a shape memory metal, as well as wire threads 13, which are made of a polymer. Wire threads 13 comprising a metal may also be connected to the functional element 11 by riveting or soldering. For wire threads 13 made of a polymer, it has proved to be advantageous to use biodegradable polymer materials. In this way, the functional element 11 can be securely positioned, whereby the wire threads 13 of the coupling element 14 dissolve after some time in the body vessel. Thus, only the functional element 11 remains in the body vessel in the long term.

In general, the wire threads 13 may be made of a drawn metal wire or polymer wire. It is also conceivable that the wire threads 13 are produced by a sputter etching process. The wire threads 13 may be connected directly to the lattice structure 12 of the functional element 11, in particular in one piece. In this case, the wire threads 13 can be produced together with the lattice structure 12 by a sputter etching method. If the grid structure 12 comprises a wire mesh, the coupling element 14 may be formed by continuation of the wire mesh, wherein the coupling element 14 preferably has a different braid angle, as the functional element 11. Further, it may be provided that the wire strands 13 at its proximal end in each case an X-ray marker element include. Alternatively, the wire strands 13 may be made entirely of a radiopaque material. Furthermore, provision may be made for the wire threads 13 to be multilayered, wherein at least one layer comprises an X-ray-visible material. For example, the wire threads 13 may comprise a core wire, which in particular comprises a nickel-titanium alloy. The core wire may be spirally wrapped by a sheath wire, the sheath wire comprising an X-ray visible material.

The wire threads 13 of the coupling element 14 are preferably arranged spirally. The spiral shape can be adapted in such a way that the coupling element 14 has a greater change in length during expansion than the functional element 11. The effect of the change in length during the expansion is called foreshortening. The enlargement of the cross-sectional diameter of the wire threads 13 or the lattice structure 12 simultaneously causes a shortening of the The coupling element 14 preferably shortens more strongly than the functional element 11. The relatively high foreshortening of the coupling element 14 dampens or delays a relative movement between the actuating element and the functional element 11. Thus, a comparatively gentle repositioning of the functional element 11 is possible. In particular, during repositioning, the coupling element 14 is first withdrawn by the actuating element into the catheter. In this first repositioning step, the catheter and the functional element 11 are held stationary. In the second repositioning step, after the coupling element 14 is arranged almost completely in the catheter, the functional element 11 is furthermore held stationary and the catheter is pushed over the functional element 11 in the distal direction. In this way, the functional element 11 already precompressed by the retraction of the coupling element 14 is further compressed and arranged in the catheter. Since the functional element 11 is held substantially stationary during the entire repositioning process, a vascular injury is avoided.

The mode of operation of the delivery system is explained below with reference to FIGS. 3a-3c:

For implantation of a stent or generally functional element 11 into a body vessel, for example a blood vessel 20, the delivery system is first guided to the treatment site (FIG. 3 a). For this purpose, the catheter 10, in which the stent or the functional element 11 is arranged in the compressed state, can be guided over a guide wire 19. The guide wire 19 may form the actuating element for the functional element 11. In this case, the guide wire 19 is detachably connected to the coupling element 14.

The release of the stent or functional element 11 is effected by a relative movement between the catheter 10 and the guide wire 19 or generally by a relative movement between the catheter 10 and the functional element 11. Preferably, the guide wire 19 or the functional element 11 is held stationary and the catheter 10 simultaneously moved in the proximal direction. In this case, the catheter 10 slides over the functional element 11, wherein a distal portion of the functional element 11 is exposed. The distal portion of the functional element 11 widens or expands in the blood vessel 20 (FIG 3b). In this case, the stent or functional element 11 is partially expanded. This means that a proximal portion of the stent or functional element 11 is furthermore arranged in the compressed state within the catheter 10.

By further movement of the catheter 10 in the proximal direction, the functional element 11 is completely released in the blood vessel 20. At the same time, the coupling element 14 is at least partially released by the proximal movement of the catheter 10. The coupling element 14 spans substantially funnel-shaped and thus forms a connection between the functional element 11 and the catheter 10. The functional element 11 can now be observed in the fully expanded state, for example by an X-ray-based imaging method. In particular, it can be observed whether, on the one hand, the position of the functional element 11 is correct and, on the other hand, the blood flow in the blood vessel 20 or mechanical activities of the vessel wall, for example caused by the pulse beat, have an effect on the position or function of the functional element 11. The connection between the catheter 10 and the functional element 11 via the coupling element 14 ensures that the functional element 11, for example for repositioning, can be withdrawn into the catheter 10. For this purpose, the catheter 10 is moved in the distal direction, that is, toward the functional element 11. The wire threads 13 of the coupling element 14 are pushed back in this way into the catheter 10, wherein the coupling element 14 is compressed. This means that the winding diameter of the spirally wound wire threads 13 is successively reduced. By the fixed connection of the wire threads 13 with the lattice structure 12 of the functional element 11 is further causes the functional element 11 is transferred from the expanded state in the compressed state. The functional element 11 is therefore compressible by a distal movement of the catheter 10 via the coupling element 14 and can be accommodated in the catheter 10. As soon as the functional element 11 is arranged inside the catheter 10, the implantation position of the functional element 11 can be corrected.

In order to completely discharge the functional element 11 in the blood vessel 20, the catheter 10 is further moved in the proximal direction until the coupling element 14 or the wire threads 13 of the coupling element 14 have completely left the catheter 10. The wire threads 13 then expand automatically and attach themselves to the proximal end 12 a of the lattice structure 12. The take Wire threads 13 and generally the coupling element 14 substantially the same outer diameter, as the expanded functional element 11 in the implanted state. The outer diameter substantially corresponds to the inner diameter of the treated body vessel, wherein the coupling element 14 and the functional element 11 can apply different radial forces on the vessel wall.

The completely dismissed functional element 11 with completely released coupling element 14 is shown in FIG.

The releasable connection between the coupling element 14 and the actuating element or guide wire 19 may be formed for example by hook-like or pin-like elements which are arranged on the guide wire 19 and on the actuating element. The hook-like or pin-like elements preferably extend in the radial direction and form, for example, a star-shaped holding means for the wire threads 13. The star-shaped holding means has a cross-sectional diameter which substantially corresponds to the inner diameter of the catheter 10. The wire threads 13 may each have a loop at the proximal ends 13b, in which the hook-like or pin-like holding element engages. The hook-like or pin-like elements fix the wire threads 13 in the axial direction. In the radial direction, the wire threads 13 are fixed by the inner diameter of the catheter 10. Once the hook-like or pin-like elements or generally the star-shaped holding element is arranged outside the catheter 10, the radial boundary for the loops of the wire threads 13 is released, so that the wire threads 13 can span in the radial direction automatically.

LIST OF REFERENCE NUMBERS

10 catheters

11 functional element

12 grid structure

12 a proximal end of the lattice structure 12

13 wire thread

13 a distal end of the wire thread 13

13b proximal end of the wire thread 13 Coupling element cell

edge cell

top

web

Crossing point guidewire blood vessel

Claims

claims

1. Delivery system for medical functional elements comprising a catheter (10) and a medical functional element (11) with a compressible and expandable, rotationally symmetrical lattice structure (12), which is displaceably arranged in the catheter (10) in the compressed state to the functional element (11) Releasing and expanding from the catheter (10) by relative movement between the catheter (10) and functional element (11), with a return mechanism provided to retract the released functional element (11) into the catheter (10).

d a d u rc h e ke n ze i c h n et that

the return mechanism comprises a flexible coupling element (14) with at least one helically arranged wire thread (13), the distal end (13a) of which is fixedly connected to a proximal end (12a) of the lattice structure (12) and the proximal end (13b) of the latter dismissed functional element (11) in the catheter (10) releasably connected to an actuating element is such that the functional element (10) by a relative movement of the wire thread (13) relative to the catheter (10) can be acted upon by a return force, which from the catheter (10) Fully released coupling element (12) is expandable such that the cross-sectional diameter of the expanded coupling element (14) is equal to or greater than the cross-sectional diameter of the expanded grid structure (12).

2. Feeding system according to claim 1,

d a d u rc h e ke n ze i c h n et that

the wire thread (13) has an impressed spiral shape such that the wire thread (13) spirals up after discharge from the catheter (10).

3. Feeding system according to claim 1 or 2,

d a d u rc h e ke n ze i c h n et that

the distal end (13a) of the wire thread (13) is attached to a tip (16) of a proximal marginal cell (15a) of the grid structure (12).

4. Feeding system according to one of claims 1 to 3,

d a d u rc h e ke n ze i c h n et that

the coupling element (14) has a plurality of wire threads (13) which are each fastened to a tip (16) of a proximal edge cell (15a) of the lattice structure (12), such that the coupling element (14) is connected to all the tips (16) of the proximal edge cells (15a) is connected.