WO2010127839A1

WO2010127839A1 - Medical catheter, medical system having such a catheter, and loader for producing such a catheter

Info

Publication number: WO2010127839A1
Application number: PCT/EP2010/002734
Authority: WO
Inventors: Michael BÜCHERT
Original assignee: Acandis Gmbh & Co. Kg
Priority date: 2009-05-04
Filing date: 2010-05-04
Publication date: 2010-11-11
Also published as: DE112010001321A5; DE102009019823A1

Abstract

The invention relates to a medical catheter for delivering a functional element (50), particularly an implant or a minimally invasive device, having a pressure-actuated displacement unit (20) acting together with the functional element (50) for delivery. The invention is characterized in that the displacement unit (20) comprises a piston (21) disposed loosely in a catheter line (10) and connected to or connectable to the functional element (50), wherein the piston (21) delimits a pressure line (15) during use, said line being designed between a proximal end of the catheter line (10) and a proximal face of the piston (21), such that the piston (21) can be axially displaced relative to the catheter line at least in segments by a pressure, particularly an overpressure and/or a vacuum, for delivering the functional element (50). The invention further relates to a medical system having such a catheter, and a loader for producing such a catheter.

Description

M / CAN-063-PC MB / JK / MP / hb / eh

Medical catheter, medical system with such a catheter and charging device for producing such a catheter

description

The invention also relates to a medical catheter-to-release a-Eunktionselements, in particular an implant or a minimally invasive device, according to the preamble of claim 1. The invention further relates to a loading device for such a catheter and a medical system with such Catheter. A medical catheter of the aforementioned type is known for example from EP 1 208 816 A2.

EP 1 208 816 A2 discloses a delivery system for inserting a stent into a blood vessel, the delivery system comprising a catheter in which a guide wire and an actuating fluid are arranged. At a distal end of the catheter, a sleeve is disposed which substantially completely surrounds the distal end of the catheter. In the region of the sleeve, the catheter has a fluid outlet opening, which is fluid-connected to the interior of the sleeve. In use, the stent to be positioned is disposed in the sheath, which sheath causes the stent to be held in a compressed state. In order to release the stent, a pressure is generated via the catheter and the liquid outlet opening within the sleeve, so that the sleeve is moved in the proximal direction as far as a stop element arranged on the catheter. In doing so, the stent arranged on the catheter is released.

The known delivery system has the disadvantage that the cross-sectional diameter of the system is relatively large due to the sleeve arranged around the catheter. In smaller body vessels, the known system is therefore not applicable. Since the delivery system has a relatively large number of components in the distal region of the catheter, the distal end of the catheter is comparatively rigid, so that positioning of stents in smaller, in particular curved, vessels is difficult. Overall, the known feeding system has a relatively complicated structure.

Another device for releasing a stent is described in EP 1 779 818 A2. The device includes a catheter in which a distal and a proximal seal are disposed, the seals defining a fluid column. The distal seal further includes a stop member fixedly connected to the catheter. The proximal seal is connected to a shaft and an actuating wire to open and close the seal can. Preferably, in the known device, a guide wire is provided, which passes through the fluid column and is connected to the distal seal. The fluid column increases the kinking stability of the catheter. To release the stent, the stem, which communicates with the distal seal through the guidewire and / or the fluid column, is held stationary. The catheter is pulled by a handpiece in the proximal direction so that the stent is exposed.

The disadvantage of the known device is that the components which are firmly fixed in the catheter make the manufacture of the device complicated and cost-intensive. Moreover, the fluid column is confined to the cavity between the seals, so that the portions of the catheter that are located outside the fluid column have a relatively high wall thickness to ensure sufficient stability. Therefore, the known device is not suitable for use in small blood vessels.

The invention is therefore based on the object to provide a catheter for releasing a functional element, in particular an implant or minimally invasive device, which has a simple structure and high flexibility and is particularly useful in small body vessels. The invention is further based on the object to provide a charging device for such a catheter and a medical system with such a catheter.

These objects are achieved with respect to the medical catheter by the subject-matter of claim 1, with regard to the medical system by the subject-matter of claim 17 and with respect to the loading device by the subject-matter of claim 18.

The invention is based on the idea of specifying a medical catheter for releasing a functional element, in particular an implant or a minimally invasive device, with a pressure-actuable displacement unit which cooperates with the functional element for release, wherein the displacement unit comprises a piston that is loose in a catheter line is arranged. The piston limits in use a pressure line which is formed between a proximal end of the catheter line and a proximal surface of the piston such that the piston for releasing the functional element by a pressure, in particular an overpressure and / or a negative pressure, at least partially relative to the catheter line is axially displaceable. The core of the invention is therefore to enable the release of a functional element by a hydraulic actuation, wherein the required catheter (hydraulic microcatheter) according to the invention has a relatively small number of components and thus a simple structure. The principle of the hydraulic release of the functional element realized according to the invention has the advantage that the flexibility of the catheter, in particular the catheter tip, is increased by the pressure column which is formed between a proximal end of the catheter line and a proximal surface of the piston. In particular, the flexible pressure column, which may comprise, for example, a liquid, ensures that the release of the functional element takes place without a guide wire or stabilizer. The stability of the catheter tip is thus achieved in the catheter according to the invention through the catheter wall and through the pressure column. The use of additional components that reduce the flexibility of the catheter tip is thus avoided. In particular, the flexible pressure column also ensures that, when the functional element is released, the catheter line does not stretch, ie forms an axial straight line, so that the risk of vascular trauma is reduced. The pressure within the catheter line, in particular within the pressure line, also reduces the risk of buckling. This means that the catheter according to the invention substantially retains its tube-like structure. The same essentially applies to the formation of wrinkles in the catheter wall. Furthermore, the small number of components reduces the manufacturing costs and the complexity of the catheter. Moreover, the piston of the displacement unit allows the reduction of friction within the catheter, which occurs for example when using guide wires. This is achieved in particular by the fact that the piston, in contrast to mechanical actuators, such as guide wires, has contact with the catheter wall over a relatively short length. In general, the hydraulic actuation of the piston and thus the hydraulic release of the functional element is controlled controllable, so that a uniform release of the functional element is possible. The direct transmission of force via the pressure column causes a direct feedback to the user, so that the release of the functional element can be detected and controlled haptically.

In a preferred embodiment of the invention, a distal end of the functional element is arranged freely in the catheter line. A proximal end of the functional element is fixedly connected to a distal end of the piston or releasably connected by a locking device such that longitudinal forces in the distal direction of the catheter line can be transmitted to the functional element under negative pressure and longitudinal forces in the proximal direction of the catheter line To move functional element in the distal or proximal direction. The feature combination of this embodiment has the advantage that the functional element can be moved in different axial directions. This will Improved nability of the functional element, since this can be withdrawn as needed in the catheter line after the functional element was partially or completely discharged. When the functional element is retracted, it is compressed by the outer edge of the catheter line and resumed in the catheter line. The mobility of the functional element in different axial directions is achieved in this imple mentation form, that the proximal end of the functional element is connected to the distal end of the piston, that can be transmitted through the piston longitudinal forces in different directions of the catheter line to the functional element. Specifically, when an over-pressure in the catheter line is established, a force is exerted on the functional element in the distal direction, so that the functional element is moved in the distal direction. By this movement, the pushing out or release of the functional element is effected. By setting a negative pressure, a force acting in the proximal direction is transmitted from the piston to the functional element, so that the functional element is moved in the proximal direction. With this movement, the released from the catheter line or partially discharged functional element is moved back into this or withdrawn. By thus given ability to correct the position of the functional element, a treating physician is enabled to make the placement of the functional element in the vessel multiple times until the functional element is at the desired location. The improved positionability of the functional element is particularly useful in the implantation of stents or other implants remaining permanently in the body.

The ability to retract the functional element by applying a negative pressure through the piston in the catheter line is also advantageous in applications in which the functional element does not permanently remain in the body, but is removed after treatment. Such applications include, for example, thrombectomy devices or recanalization devices. Other applications in which the retraction of the functional element makes sense are also covered by this embodiment.

In a further preferred embodiment, the piston is displaceably guided on a guide means, in particular on a guide wire. This has the advantage that the guide means, in particular the guide wire for probing remains stationary relative to the catheter line. Between the piston and the guide means, a relative movement is generated by the pressurization.

In order to achieve a high degree of flexibility over the entire length of the catheter line or of the medical catheter, the pressure line can be formed substantially free of installation. In this way, a uniform pressure transfer from the proximal end of the catheter line to the proximal surface of the piston is made possible.

The pressure line may be integrally formed with the catheter line. The catheter line is thus at least partially formed as a pressure line. In this case, the pressure line is preferably limited by the proximal surface of the piston. This means that the length of the pressure line or the length of the catheter line section, which forms the pressure line, varies in use depending on the local position of the piston. The medical catheter thus preferably comprises two mutually movable components, on the one hand the catheter line, which is formed in sections as a pressure line, and on the other hand, the displacement unit, in particular the piston, which is displaceable in the catheter line. The piston may additionally be connected to the function of dement, wherein the function can be part of the shift unit dement. For example, the functional element may comprise a device for temporary vessel opening, which is firmly connected to the piston of the displacement unit.

In a preferred embodiment, an end stop is arranged at a distal end of the catheter line. By the end stop is advantageously prevented that the displacement unit, in particular the piston is completely discharged from the catheter line. The end stop thus limits the pressure-actuated or hydraulically actuated movement of the piston within the catheter line in the axial direction.

The end stop may be formed by a distal taper of the catheter lead. Further, the end stop may comprise a rigid or flexible sleeve or a spiral wire element. In this way, the end stop is easy and inexpensive to produce.

As a result, the tubular catheter line can be easily and inexpensively equipped with an end stop.

In a further preferred embodiment of the medical catheter according to the invention, the displacement unit comprises at least one sealing means, which is connected to the piston and seals against the catheter line in order to ensure a fluid-tight boundary of the pressure line.

The displacement unit preferably has a proximal sealing element which seals against the catheter line under the influence of a force acting in the distal direction. In this case, the sealing takes place during a movement of the piston in the distal direction, wherein the length of the pressure line is increased. By the proximal sealing element is thus achieved that the Generation of an overpressure in the pressure line has a distal movement of the piston result. The proximal sealing element thus ensures the sealing of the pressure line when an overpressure is generated in the pressure line.

Alternatively or additionally, the displacement unit may comprise a distal seal which seals against the catheter line under the influence of a force acting in the proximal direction. In this case, the sealing or distal boundary of the pressure line takes place upon generation of a negative pressure in the pressure line. In this way, it is achieved that the piston is generally movable axially in the catheter line in the proximal direction through the generation of a negative pressure in the main pressure line. This has the advantage that a functional element to be released can be withdrawn even after release, which has already taken place in some cases, into the catheter line.

The piston may have a flexible, in particular articulated connection or articulated connection. Preferably, the flexible connection or articulation between the proximal and the distal seal is arranged accordingly. The flexible connection allows the use of the catheter in small, tightly wound vessels, since curvatures or bends of the catheter are compensated.

The proximal and / or distal sealing may comprise a cascade seal. The cascade seal can be constructed, for example, from multiple, preferably in series successively arranged sealing means. The cascade seal allows a particularly efficient and secure sealing of the piston with respect to the catheter line.

The sealing means may further comprise an annular, flexible sealing lip disposed in a radially outer region. In general, the sealing means are circular in shape corresponding to the inner cross section of the catheter conduit. In this case, a radially outer region along the circumference can be formed as a sealing lip. The flexible sealing lip ensures that the sealing of the piston with respect to the catheter line is ensured at least in a direction of movement of the piston. At the same time is achieved by the flexible sealing lip, that in an opposite direction of movement of the piston, the friction between the sealing means and the catheter line is reduced, so that a simple and uniform axial displacement of the piston is achieved. In particular, is reduced by the flexible sealing lip of the contact pressure of the sealant to the catheter line, which has a positive effect on the breakaway torque at the initiation of the piston movement. In a further preferred embodiment of the medical catheter according to the invention, the displacement unit comprises an adapter which is adapted for positive connection with the functional element. By means of the positive connection, a particularly simple possibility is provided for dismissing the functional element from the catheter or from the catheter line. In particular, it is avoided by the positive connection that additional actuators are provided to release the functional element.

Particularly advantageously, the positive connection is achieved in that the adapter includes an undercut for receiving the Eunktionselements.

Preferably, the adapter is arranged distal to the sealing means, so that the functional element is held outside the pressure line.

The adapter may further be integrally formed with the piston. The structure of the catheter, in particular the displacement unit, thereby further simplified and reduces the manufacturing cost.

In a further preferred embodiment of the inventive medical catheter, the catheter tube has an internal diameter that is less than 2.0 mm, in particular less than 1.5 mm, in particular less than 1.0 mm, in particular less than 0.75 mm , in particular less than 0.5 mm and / or comprises a wall thickness which is less than 0.25 mm, in particular less than 0.2 mm, in particular less than 0.15 mm, in particular less than 0.1 mm. Such a catheter line has a particularly high flexibility with small dimensions, whereby the catheter is advantageously used, in particular in cerebral blood vessels.

Furthermore, it is preferred if the inner wall of the catheter line with the displacement unit, in particular the sealing element, at least partially has a dynamic coefficient of friction which is less than or equal to 0.35, in particular less than or equal to 0.30, in particular less than or equal to 0.20, in particular less than or equal to 0.10, in particular less than or equal to 0.09, in particular less than or equal to 0.08, in particular less than or equal to 0.07, in particular less than or equal to 0.06, in particular less than or equal to 0.05, in particular smaller or equal to 0.04, in particular less than or equal to 0.03, in particular less than or equal to 0.02. The relatively low coefficient of friction allows a particularly simple and easily controllable, in particular haptically controlled controllable, release of the functional element. The lower limit of the friction coefficient may be 0.01. According to a sibling aspect of the invention, a medical system comprises the previously described catheter and a pressure generating unit which is fluid-connectable to the catheter conduit, in particular to the pressure conduit, such that the pressure acting on the proximal surface of the piston is adjustable.

Another, subsidiary aspect of the invention is based on the idea to provide a loading device with a tubular or tubular introducer, in which a displacement unit is arranged, wherein the displacement unit comprises a piston which dement, with a function dement, or -mimplant or minimally invasive Device, - connected and loosely arranged in the introducer sheath. The introducer sheath is connected on the one hand with a pressure generating unit and on the other hand with a catheter line such that the displacement unit for producing the previously described catheter is hydraulically and / or mechanically actuated inserted into the catheter line.

The invention is explained in more detail below on the basis of exemplary embodiments with reference to the accompanying schematic drawings. Show in it

1 shows a longitudinal section through a medical catheter according to the invention according to a preferred embodiment;

2 shows a longitudinal section through the tip of a catheter line of the medical catheter according to the invention according to a preferred embodiment;

3 to 8 each show a longitudinal section through a piston of a medical catheter according to the invention according to a preferred embodiment;

9 to 11 a longitudinal section through a blood vessel during the positioning of a medical catheter according to the invention according to a preferred embodiment;

12 and 13 a longitudinal section through a medical catheter according to the invention with a charging device during the loading of a functional element into the catheter line according to a preferred embodiment; FIG. 14 shows a longitudinal section through a catheter according to the invention during the

Releasing a functional element into a blood vessel according to a preferred embodiment;

FIG. 15 shows a longitudinal section through a catheter according to an embodiment of the invention with a piston arranged on the guide wire and adapted for repositioning the functional element; FIG.

Fig. 16 shows a variant of the embodiment according to Fig. 15 "piston_by_ the piston" slidably connected to the guide wire by means of sealing rings;

FIG. 17 shows the piston according to FIG. 15 in a catheter tip near position shortly before the release of the functional element; FIG.

FIG. 18 shows the piston according to FIG. 15 in a position in which the function is partially released; FIG.

FIG. 19 shows the piston according to FIG. 15 in a position in which the functional element has been completely discharged; FIG. and

FIG. 20 shows a variant of the embodiment according to FIG. 15, in which the functional element is firmly connected to the piston.

1 shows a cross section through a blood vessel 51 with a plaque 52. The plaque 52 represents a pathological constriction of the blood vessel 51 and hinders the blood flow, so that the nutrient supply of downstream tissue is endangered. In order to prevent the plaque 52 from further closing off the blood vessel 51, a functional element 50, in particular a stent or stent-graft, is inserted into the vessel section to be treated with a medical catheter according to the exemplary embodiment described here.

The medical catheter in this case comprises a catheter line 10, which has a substantially circular cross-section. The catheter line 10 comprises a flexible wall, so that the catheter line 10 is formed substantially tubular. Preferably, the catheter tube 10 is made of a biocompatible, in particular sterilizable, plastic. At an distal end of the catheter line 10, an end stop 13 is arranged. The clear cross section or the inner diameter of the catheter line 10 is preferably smaller in the region of the end stop 13 than in the rest of the catheter line 10. This means that the End stop 13 is annularly arranged on an inner surface 12 of the catheter wall 10. The end stop 13 may cover the inner peripheral surfaces of the catheter line 10 only partially. For example, the end stop 13 may have individual, distributed over the inner circumference of the catheter line 10 and spaced from each other arranged stop elements.

Within the catheter conduit 10 a piston 21 is arranged in use. According to FIG. 1, the piston 21 comprises a proximal sealing element 30a and a distal sealing element 30b, wherein the sealing elements 30a, 30b are formed together in a double-cone shape, so that sealing of the sealing diaphragm 30a, 30b is secured against the catheter line 10_. In particular, the double conical arrangement of the sealing elements 30a, 30b ensures that a seal is ensured when the piston 21 is moved both proximally and distally in the catheter line 10. The piston 21 is preferably rotationally symmetrical or has a circular cross section. At an distal end of the piston 21, an adapter 22 is arranged, which comprises a positive-locking element 24. By the adapter 22, the piston 21 is adapted to the functional element 50, so that the functional element 50 is releasably connected to the piston 21. The detachable connection preferably takes place in a form-fitting manner through the positive-locking element 24.

The sealing elements 30a, 30b, the piston 21 and the adapter 22 and the form-fitting element 24 together form the displacement unit 20. The displacement unit 20 is disposed within the catheter line 10 and axially displaceable in this. The displacement can take place both in the proximal and in the distal direction. In this case, the sealing elements 30a, 30b seal against the catheter line 10, so that the displacement unit 20 defines a pressure line 15 arranged proximally to the displacement unit 20. As a pressure line 15 so a portion of the catheter line 10 is referred to, which extends from a proximal end of the catheter line 10 to a proximal end of the displacement unit 20. The length of the pressure line 15 can thus vary depending on the position of the displacement unit 20 in the catheter line 10.

As indicated in FIG. 1 by the designations P + and P-, a higher pressure is generated in the pressure line 15 for releasing the functional element 50 than is present in the blood vessel 51. In this way, as shown by the arrow in Fig. 1, the displacement unit 20 is moved in the distal direction, so that the functional element 50 is released into the blood vessel 51. The procedure for positioning and releasing the functional element 50, in particular a stent, will be explained in more detail later in connection with FIGS. 11 to 14. In order to achieve that the displacement unit 20 is held within the catheter line 10, the catheter line 10 has an end stop 13. The end stop 13 may, for example, as shown in the longitudinal section of FIG. 2, be formed. In this case, the tip of the catheter line 10 or the catheter tip on a taper 14, whereby the inner diameter of the catheter line 10 is reduced. The taper 14 connects a piston portion 17, in which the piston 21 or the displacement unit 20 is arranged, with an end portion 18. An outer wall 11 of the catheter line 10 extends substantially straight across the entire catheter line 10 and also forms in the region of the end portion 18th a tip core 16L The catheter lead 10 has as_p at a disjoint end a cone-shaped tip, ie the tip cone 16. The catheter tip or the distal end of the catheter line 10 have a relatively small wall thickness, whereby the flexibility of the catheter ^tip is increased ^■ . In particular, relatively soft materials for the production of the catheter tip are also provided, so that the catheter tip is atraumatic effect.

In the region of the piston portion 17, the catheter line 10 further comprises an additional inner wall 12 which is fixedly connected to the outer wall 11. The outer wall 11 and the inner wall 12 preferably differ by material properties. In particular, the inner wall 12 has a material with a low coefficient of friction, so that the friction between the inner wall 12 and the displacement unit 20, in particular the sealing elements 30a, 30b, is small. Preferred materials are PTFE or FEP. The low coefficient of friction can be achieved by surface treatment or modification technologies such as coating or nano-coating. Preferably, surface-modified plastics are used for the inner wall 12. The surface modification can be done at the molecular level. For example, the inner wall 12 may comprise polyurethane or Pebax, wherein a relatively high Shore hardness of the material is expedient. Preferably, a Shore hardness of at least 72 D. Both the inner wall 12 and inner sliding surface of the catheter line 10, as well as the sealing means 30 may comprise such materials, in particular surface-modified plastics.

In the region of the taper 14, the end stop 13 is also arranged. In this case, the end stop 13 also partially extends into the end section 18. The end stop 13 preferably comprises a material which has a higher rigidity than the catheter line 10, in particular the outer wall 11. For example, the end stop 13 may comprise a sleeve made of metal or plastic. Alternatively, it is possible for the end stop 13 to comprise a spiral sleeve or spiral wound wire element which is spring-mounted in the catheter tip and increases the flexibility of the catheter tip. The end stop 13 can thereby at least partially include a radiopaque material to facilitate positioning of the catheter or catheter tube 10 in a body vessel.

FIGS. 3 to 8 show different variants of the displacement unit 20. In general, the displacement unit 20 comprises the piston 21, which is preferably arranged coaxially with the catheter line 10. In a proximal portion of the piston 21, sealing means 30 are arranged. The sealing means 30 are firmly connected to the piston 21. The proximal portion or sealing portion 21a of the piston 21 is preferably separated by a push plate 25 limited to one side distal portion or adapter portion 21b. The thrust plate 25 has a cross-sectional diameter which is smaller than the inner diameter of the catheter tube 10. In this way, it is ensured that the contact between the displacement unit 20 and the catheter line 10 takes place only by the sealing means 30. The sealing means 30 thus limit the pressure line 15 or the pressure line section of the catheter line 10.

According to FIG. 3, the displacement unit 20 has a plurality of dish-shaped sealing means 30. In each case, three sealing means 30 form a cascade-like, proximal sealing element 30a and a cascade-like, distal sealing element 30b. The proximal seal member 30a and the distal seal member 30b are spaced from each other. The plate-like sealing means 30 further comprise a radially outer portion 32 which has a relatively high flexibility and forms a sealing lip 31. Due to the high flexibility of the sealing lip 31 or of the radially outer region 32, the secure sealing of the sealing means 30 against the catheter line 10, in particular the low-friction inner wall 12, is achieved. The curvature of the plate-like sealing means 30 is aligned or formed as shown in FIG. 3 in the distal direction. It is thereby achieved that, on the one hand, the movement of the displacement unit 20 in the distal direction and, on the other hand, the sealing of the sealing means 30 against the catheter line 10 takes place through an overpressure which is generated in the pressure line 15. The displacement unit 20 is thus designed by the arrangement of the sealing elements 30 for the distal displacement of the displacement unit 20, as shown schematically by the arrow in Fig. 3.

A displacement on both sides of the displacement unit 20, ie a displacement in the distal and in the proximal direction, allows, for example, the seal arrangement according to FIG. 4. The construction of the displacement unit 20 according to FIG. 4 essentially corresponds to the construction of the displacement unit 20 according to FIG Difference that the cascade-like, distal sealing member 30b is arranged offset. The plate-like sealing means 30 of the distal sealing member 30b thus have a proximally directed curvature. In this way you- 10, the sealing means 30 of the distal seal member 30b when moving the displacement unit 20 in the proximal direction against the catheter line 10, in particular the inner wall 12 from. Such a movement of the displacement unit 20 takes place, for example, by generating a negative pressure in the pressure line 15. In addition, it is provided according to FIG. 4 to arrange a flexible articulated connection 33 between the proximal sealing element 30a and the distal sealing element 30b. The flexible hinge 33 is shown schematically in the figures by a solid circle. The flexible articulated connection 33 ensures that the flexibility of the displacement unit 20 is increased, so that the displacement unit 20 can follow a curvature of the catheter line 0,

FIG. 5 shows the displacement unit 20 according to FIG. 4, wherein a functional element 50 is arranged in the adapter section 21b of the piston 21. The function dement 50 may be releasably or firmly connected to the adapter portion 21b and the adapter 22. A detachable connection is particularly advantageous in the case of functional elements 50 which are designed as stents or generally as implants. Such functional elements 50 remain in the body after positioning. Alternatively, the functional element 50 may comprise a microsurgical instrument, for example a thrombosis trap or retriever. The function is preferably dement 50 preferably connected to the adapter 22. The connection can be positive or non-positive. For example, the functional element 50 may be crimped onto the adapter 22. It is also possible that the adapter 22 comprises an undercut, which cooperates with the functional element 50 for the positive connection. Another possibility for positive connection, for example, x-ray markers, which are assigned to either the adapter 22 or the functional element 50. In this case, the adapter 22 may be adapted to accommodate standard functional elements, for example standardized implants such as stents or stent grafts. Alternatively, the structure of the functional element 50 can be adapted to the displacement unit 20, in particular the adapter 22. For example, corresponding implants may have loops, cells or other geometric properties that allow a fixed or detachable connection to the adapter 22. Alternatively, the connection between functional element 50 and adapter 22 may be made in a material-locking manner, for example by gluing, welding or soldering.

It is possible that the adapter 22 comprises a Nitinol core with wire winding. The functional element 50 may have self-expanding properties, so that in the case of a positive connection between the functional element 50 and the adapter 22, the positive connection is released automatically by the release of the functional element 50 from the catheter line 10. Other releasable connections between functional element 50 and adapter 22 are possible. For example, the detachable connection by electrochemical detachment, mechanical, geometric, in particular by hooks, pins or a snap connection, hydraulically or electrically.

FIG. 6 shows a further exemplary embodiment of a displacement unit 20. In this case, the displacement unit 20 has a piston 21 which is divided by the push plate 25 into the seal 21 a and the adapter section 21 b. Sealing means 30 are arranged in the sealing section 21a, with two sealing means 30 each forming the proximal sealing element 30a and the distal sealing element 30b. The proximal sealing element 30a and the distal sealing element 30b-are connected by a flexible articulated connection 33 which is defined by the circle. The sealing means 30 according to FIG. 6 are annular or disk-shaped and have a rounding in a radially outer region 32, so that the sealing means 30 ensure reliable sealing against the catheter line 10, in particular the inner wall 12, in both directions of movement of the displacement unit 20 , In the adapter portion 21b of the displacement unit 20, the functional element 50 is arranged. By a further filled circle in the adapter portion 21b, a positive locking element 24 is indicated, which allows the connections between the functional element 50 and displacement unit 20.

FIG. 7 shows a similar exemplary embodiment. In contrast to the exemplary embodiment according to FIG. 6, the displacement unit 20 according to FIG. 7 has a piston 21 which has a substantially larger cross-sectional diameter than the piston 21 according to FIG. 6. The sealing means 30 are preferably designed as O-rings which are fixedly arranged on the piston 21, in particular in the sealing portion 21a. In total, four O-rings are provided, with two O-rings each forming the proximal sealing element 30a and the distal sealing element 30b. Between the proximal seal member 30a and the distal seal member 30b, a flexible hinge 33 is disposed.

A further variant of the displacement unit 20 is shown in FIG. 8. In this case, the adapter portion 21b of the piston 21 with the thrust plate 25 substantially corresponds to the exemplary embodiment according to FIG. 7. In the sealing portion 21a, however, an alternative sealing means 30 is arranged. The sealing means 30 substantially completely engages over the proximal end of the piston 21 and has in a radially outer region 32 a sealing lip 31 which is articulated on a distal region of the sealing means 30. The sealing lip 31 extends beyond the proximal end of the piston 21 in the axial direction and is preferably cone-shaped, so that the sealing lip 31 comes into contact with the inner wall 12 of the catheter line 10 at least at its proximal end. Preferably, the sealing lip 31 is formed as a play compensation lip. The sealant 30 shown in Fig. 8 offers a Reliable sealing of the displacement unit 20 relative to the catheter line 10 in a movement of the displacement unit 20 in the distal direction, as indicated by the arrow in Fig. 8.

The mode of operation of the medical catheter is explained in more detail below with reference to FIGS. 9 to 14:

For the treatment of plaque 52 or generally of a lesion in a blood vessel, a guidewire 51 is first inserted into the blood vessel 51 to the treatment site 40 and vorgescho- -ben _τ as-in-Fig.- 9-dargestellt.-The-Euhrungsdraht-40- may include a conventional wire or guide wire.

In a next step, a microcatheter or the catheter line 10 is introduced via the guide wire 40 into the blood vessel 51 and positioned in the region of the plaque 52. The catheter line 10 or the microcatheter is preferably rinsed by a liquid, in particular saline solution (NaCl). This process is shown in FIG.

FIG. 11 shows that the guide wire 40 is removed from the blood vessel 51 and the microcatheter or catheter line 10 in a subsequent step.

In a further step, the microcatheter or the catheter line 10 is loaded or loaded with the displacement unit 20 and the functional element 50. For this purpose, the catheter line 10 has a connector 41 at a proximal end outside the patient 53. The connector 41 is preferably designed as a Luer connector.

A loading device 100 comprises an introducer sheath 110, in which the displacement unit 20 is arranged axially displaceable. Furthermore, the functional element 50 is arranged in the introducer sheath 110. The functional element 50 is connected positively in accordance with FIG. 12 with the displacement unit 20. For this purpose, the adapter 22 of the displacement unit 20 is designed as a form-fitting adapter or positive-locking element 24. In order to introduce the displacement unit 20 into the catheter line 10, the loading device 100 or the introducer sheath 110 is connected to the connector 41, so that the introducer sheath HO is arranged coaxially to the catheter line 10. In a proximal portion of the introducer sheath 110, which is delimited by the displacement unit 20, a pressure, in particular overpressure, is generated, so that the displacement unit 20 is pushed into the catheter line 10. In this case, both the microcatheter or the catheter line 10, and the introducer sheath 110 are filled with a saline solution. The saline solution serves as a pressurized fluid for advancing the displacement unit 20. With regard to the structure and the handling, the introducer sheath 110 thus corresponds essentially to the Catheter line 10. It is not excluded that the transfer of the displacement unit 20 from the introducer sheath 110 in the catheter line 10 is at least partially mechanical. For example, it is possible for the displacement unit 20 to be moved mechanically out of the introducer sheath 110 into the previously flushed, ie fluid-filled, catheter line 10. In a further step, the introducer sheath 110 is removed and in its place the pressure generating unit 44 is connected to the catheter conduit 10 to hydraulically control the movement of the displacement unit 20 in the catheter conduit 10.

Once the slide unit_20 is located in the catheter line-10, the loader 100 and the introducer sheath 110, respectively, are disconnected and a pressure generating unit 44 is connected to the connector 41. The pressure-generating unit 44 preferably comprises a pressure regulator 43 and a pressure gauge 45. The pressure-generating unit 44 is connected to the connector 41 via a fluid reservoir 42, which ensures the supply of liquid into the pressure line 15 or the pressure line section of the catheter line 10. With the pressure generating unit 44, both an overpressure for advancing the displacement unit 20 and a negative pressure for retracting the displacement unit 20 can be generated in the pressure line 15. The interaction of the catheter line 10 or the displacement unit 20 with the pressure generating unit 44 is shown in FIG. 13.

As shown in FIG. 14, overpressure generation by the pressure generating unit 44 causes an increased fluid pressure in the pressure line 15. That is, the pressure in the pressure line 15 is greater than the pressure in the blood vessel 51. The distal to the displacement unit 20 in the catheter line 10 arranged rinsing liquid is displaced by the feed of the displacement unit 20 into the blood vessel. As shown in FIG. 14, the functional element 50 is advanced into the area of the plaque 52. In this case, the catheter line 10 is positioned such that the distal end of the catheter line 10 or the catheter tip is arranged distal to the plaque 52.

The release of the functional element 50, here a stent, preferably takes place as shown in FIG. In this case, the catheter line 10 is retracted in the proximal direction and held by corresponding hydraulic pressure in the pressure line 15, the displacement unit 20 substantially stationary. In this way, the functional element 50 is released from the catheter line 10 and thereby expands automatically. As soon as the displacement unit 20 has reached the end stop 13, the positive connection between the functional element 50 and the displacement unit 20 or adapter 22 is released, so that the functional element 50, in particular the stent, is completely released in the blood vessel 51. It is also possible that in the pressure line 15 before the complete release of the functional element 50, a negative pressure is generated to to pull the functional element 50 back into the catheter line 10. This can be expedient in order to achieve an exact positioning of the functional element 50.

Another embodiment is shown with different variants in FIGS. 15-20. The exemplary embodiment makes it possible to reposition the functional element 50 by retracting the dismissed or partially released functional element 50 into the catheter line 10. The concrete exemplary embodiment according to FIG. 15 comprises a displacement unit 20, which in principle, like the displacement units 20, according to the exemplary embodiments described above. As used herein, the displacement unit 20 comprises a piston 21, the proximal seal portion 21a, and a distally disposed adapter portion 21b. The distal sealing portion 21 a seals against the inner wall 12 of the catheter line 10. The distal adapter portion 21 b is adapted for connection to the functional element 50. The adapter from section 21b comprises a locking device 26 which is releasably connected to the proximal end 50b of the functional element 50 and that in the compressed state of the functional element 50 in the catheter line 10. The distal end 50a of the functional element 50 is arranged freely in the catheter line. This relates to the state of the system in which the piston 21 is arranged with the functional element 50 completely in the catheter line 10, as shown in Figs. 15-17. The piston 21 thus interacts in a direct manner only with the proximal end 50b of the functional element 50. The distal end 50a of the functional element is not held directly by the piston 21, i. the distal end 50 a of the functional element 50 is not connected directly to the piston 21 and is thus freely arranged in the catheter line 10. This is achieved in the embodiment according to FIG. 15 in that the dimension of the locking element 26 or its longitudinal axial extension is limited to the proximal end 50 b of the functional element 50. The locking element 26 is thus shorter in the compressed state of the functional element 50 than the functional element 50, wherein this dimensioning is not mandatory.

The configuration of the locking member 26 will be described with reference to Figs. 15 and 19 which show the locking member 26 engaged with the proximal end 50b of the functional member 50 (Fig. 15) and disengaged (Fig. 19). The locking element 26 comprises a recess 27, which is open in the radial direction and adapted to receive a corresponding counterpart 54 of the functional element 50. The counterpart 54 can be designed, for example, as an X-ray marker and is arranged at the proximal end 50 b of the function selements 50. The counterpart 54 or the x-ray marker extends inward in the radial direction into the inner lungs of the functional element 50. In the compressed state (FIG. 15), the counterpart 54 is received in the recess 27, at least partially received. The axial length of the recess 27 corresponds approximately to the axial length of the counterpart 54 or is slightly larger, as seen in Fig. 15. The recess 27 is adapted such that the longitudinal direction in both the distal and in the proximal direction of the catheter line 10 from the piston 21 to the arranged in the recess 27 counterpart 54 are transferable. For this purpose, as mentioned above, the length of the recess 27 is adapted to the length of the counterpart 54, so that the recess 27, the article 54 upon movement in both axial directions, the functional element 50 each entrains. For this purpose, the counterpart 54 engages in the recess 27 so far that the lateral edges of the recess 27 engage over the counterpart 54 and form a stop for the counterpart 54 in both the distal and in the proximal direction. In the compacted-state-thus-the-arrest-forming-at-the-and-the-pr-oximale-end-SOb-of-the-constituent element 50 form a form-fitting, detachable connection.

It is not necessary that the counterpart 54 completely fills the recess 27 in the compressed state of the functional element 50, i. reaches to the bottom of the recess 27. As shown in Fig. 15, it is sufficient if the counterpart 54 engages at least partially in the recess 27.

The recess 27 may be annular. It is also possible that the recess 27 forms individual pockets into which the counterpart 54 engages. The counterpart 54 is in each case formed complementary to the recess 27. The counterpart 54 may be annular or offset.

The recess 27 is formed by a web-shaped extension 28 and an annular end 29 whose diameter is greater than the diameter of the web-shaped extension 28. The web-shaped extension extends centrally in the longitudinal direction of the piston 21 in the distal direction. The recess 27 is formed between the end 29 and a distal shoulder 29 a of the piston.

In the shoulder 29a, a further longitudinal recess 29b is formed, which serves to receive the end stop 13 on the catheter tip, as shown in Fig. 19.

Other possibilities of releasable connection between the piston 21 and the functional element 50 by a locking device are conceivable.

The piston 21 further comprises a central passage opening through which in use a guide means, in particular the guide wire 40 is guided. The piston 21 is movable relative to the guide wire 40. In the embodiment of FIG. 15, the inner diameter of the passage opening corresponds to the outer diameter of the guide wire 40, so that the piston 21 is guided directly on the guide wire 40. Alternatively, as shown in FIG. 16, the inner diameter of the through hole may be slightly larger than the outer diameter of the guide wire 40. In the passage opening sealing rings 34, for example, two or more sealing rings 34 are arranged, on which the guide wire 40 slides. In both cases, the piston 21 is sealed against the guide wire 40, so that proximal side of the piston 21, an overpressure or a negative pressure on the proximal surface of the piston can act without a pressure loss arises.

The passage opening extends longitudinally along the longitudinal direction of the piston 21. The guide wire 40 and the piston 21 are therefore arranged coaxially in use.

The exemplary embodiments according to FIGS. 15-19, which enable a detachable connection of the piston with the functional element 50, are in particular, but not exclusively, intended for the positioning of implants which remain permanently in the body, such as stents. In other applications, such as thrombus, which do not remain permanently in the body, but must be removed after treatment, the embodiment of FIG. 20 is provided. The piston 21 according to FIG. 20 is constructed in principle like the piston 21 according to the embodiments in FIGS. 15-19. In that regard, all features of the piston 21 according to FIGS. 15-19 are also disclosed in connection with the piston 21 according to FIG. 20. The difference is that the distal end 21c of the piston 21 is fixed, i. is not detachably connected to the proximal end 50b of the functional element 50. In contrast, in the case of the piston 21 according to FIGS. 15-19, the distal end 21 c of the piston 21 is releasably connected to the proximal end 50 b of the functional element 50 due to the locking device 26. prevented. The distal end 50 a of the functional element 50 is arranged freely in the catheter line 10 in the compressed state. In this regard, reference is made to the imple mentation form in connection with Figs. 15-19. As in the previous embodiments can be withdrawn with the piston 21 shown in FIG. 20, the function is accordingly 50 in the dismissed, even in the fully discharged state by applying the piston 21 with a negative pressure in the catheter line 10. The piston 21 is, as in the examples according to FIGS. 15-19, displaceably guided on an inner guide wire 40. The guidewire 40 may be fixed in position relative to the catheter lead 10 for probing.

The mode of operation of the exemplary embodiments according to FIGS. 15-20 is explained below:

In Fig. 15 the charged state of the system is shown, wherein the piston 21 is arranged together with the functional element 50 close to the proximal end of the catheter, that is close to the lock. From Fig. 15 it is clear that the entire displacement unit with the func- Onselement 50 is not fixed to the catheter tip, but can be loaded on the proximal side in the catheter, whereby the handling of the system is simplified. For this purpose, the introducer sheath 110 is adapted accordingly. The displacement device 20 is thus intended to be moved from the proximal end of the catheter to the distal end or to the catheter tip.

By acting on the piston 21 with an overpressure (P +), the piston 21 is moved together with the function dement in the direction of arrow along the guide wire 40 to the catheter tip -bzw.-in-the -Katheterspitzen near-range, -how-in-Eig FIG. 17 illustrates this for both embodiments according to FIG. 15, FIG. 16, as well as for the embodiment according to FIG. 20. In FIG. 18 the system is shown in partially released state. In this case, the distal end 50a of the functional element 50 is released and expanded. The function dement 50 is in sections on the vessel wall. The proximal end 50b of the functional element 50 is located in the catheter line 10. Through the inner wall of the catheter line 10, the proximal end 50b is held in the compressed state, so that the engagement between the counterpart 54 and the recess 27 at the distal end of the piston 21b or detachable connection between the distal end 21c of the piston 21 and the proximal end 50b of the functional element 50 remains. Since the connection is formed such that forces can be transmitted from the piston 21 to the functional element 50 in both axial directions, in the state shown in FIG. 18, the functional element 50 can be withdrawn into the catheter line 10 by applying a negative pressure to the piston 21. This results in a compression of the already discharged portion of the functional element 50 at the inlet opening of the catheter tip, so that the diameter of the discharged portion of the functional element 50 is reduced. It is possible to completely retract the functional element 50 in the catheter line 10. Thus, the attending physician has the ability to reposition the catheter tip to make the placement of the functional element or the stent again at a slightly different location in the vessel. To push out the functional element 50, the piston 21 is subjected to an overpressure, whereby a movement of the piston 21 is generated in the distal direction. Upon complete discharge of the functional element 50, the piston 21 strikes the end stop 13, as shown in FIG. In this case, the recess 27 or generally the locking device 26 leaves the catheter line 10. The proximal end 50b of the functional element 50 comes free, so that the counterpart 54 leaves the recess 27. The distal end 21c of the piston 21 and the proximal end 50b of the functional element 50 are disengaged. The implant is thus completely discharged. In this condition, the implant can not be retracted again. In contrast, it is possible in the embodiment according to FIG. 20 to retract the functional element 50 even when completely discharged, since the proximal end 50b of the functional element remains connected to the distal end 21c of the piston 21 due to the fixed or non-detachable connection , The particular advantage of the embodiments according to FIGS. 15-20 underlying concept is that the hydraulically assisted mobility of the displacement element 20 in both axial directions together with the locking of the functional element 50 and the fixed connection allows a retraction function. Moreover, by using a guide wire on which the piston 21 is guided, the stent may protrude. a complete stent can be completely withdrawn and a new stent loaded into the system if the operation proves that the implant or specifically the stent is not the correct size, for example not the correct diameter or length. Furthermore, the positioning can be corrected if necessary. To do this, the implant is pulled back into the catheter, the guide wire is pushed forward and then the implant is released again. The feature combination of the locking element or the fixed connection and the inner guidewire allows rapid handling of the system. The ability to move the plunger to the proximal end of the catheter and thereby load a new stent or implant increases the flexibility of the system.

All features of the embodiments according to FIGS. 15-20 are disclosed and claimed together with the features of the other embodiments.

The medical catheter combines the following advantages:

High flexibility in the distal region for improved target accessibility, especially in small arteries less than 2 mm in diameter,

High flexibility in feeding the catheter line 10, since no components are arranged within the catheter line 10 in this method step,

Reduction of the loading of the vessels or vessel walls by lateral pressure, since the fluid column of the pressure line 15 follows the vessel curvature,

Easy to handle, accurate and uniform control of the release process,

Low risk of buckling and little wrinkling, Low number of components, reducing costs and complexity

Low friction within the catheter line 10, since a compact design of the displacement unit 20 is possible.

In general, the medical catheter of the present invention is useful for releasing laser-cut open-cell and closed-cell stents and braided stents. Specifically, closed-cell stent and braided stents can, if necessary by applying a negative pressure in the pressure line JJI again in _^ the catheter tube 10 withdrawn. become. Furthermore, the catheter according to the invention can be used for releasing filters, baskets or retrievers. Such functional elements 50 are preferably fixedly connected to the adapter 22 and are retracted back into the catheter line 10 after use.

Particularly suitable is the medical catheter according to the invention for the treatment of lesions in cerebral blood vessels, which have a small relatively small cross-sectional diameter, since the catheter according to the invention can be relatively small in size. This is possible because guidewires or stabilizers and similar components can be dispensed with.

The sealing means 30 or sealing elements 30a, 30b of the displacement unit 20 or the pressure piston can be designed to be acting or acting on both sides. As shown in FIGS. 3 to 8, therefore, the sealing means 30 can be designed for one or both effective directions. In order to ensure a secure seal, the sealing demente 30a, 30b are preferably formed as a cascade seal. The contact pressure between the sealing means 30 and the inner wall 12 of the catheter line 10 is preferably low, so that a low friction or a low breakaway torque between the sealing means 30 and the inner wall 12 is present. At least in a radially outer region 32 or at the periphery, the sealing means 30 are flexible.

The pressure piston or the piston 21 preferably has a flexible body or a flexible axis, so that the piston 21 or a total of the displacement unit 20 can follow curvatures of the catheter line 10. The piston 21 may also consist of a plurality of coupled together cells or sections.

The adapter portion 21b of the piston 21 may comprise a flexible coil, a nitinol wire or a geometry suitable for connection to the functional element 50. Overall, the invention is based on the basic idea of arranging a freely movable, loosely arranged displacement unit 20 in a catheter line 10 or a microcatheter which limits a fluid pressure column formed by the user as far as the displacement unit 20. The user can only act on the displacement unit 20 hydraulically. A mechanical connection between the displacement unit 20 and the user in the intended use of the catheter or during the mechanical treatment is not provided. This does not exclude that the displacement unit 20 is mechanically actuated, for example when loading the catheter line 10. The loose arrangement of the displacement unit 20 means in the frame of the invention that the displacement unit 20 is arranged substantially axially freely movable in the catheter line 10, the movement of the displacement unit 20 being controllable by the fluid column in the pressure line 15 is. The control is effected by the pressure generating unit 44. In this case, the Druckz eugungseinheit 44 preferably include the fluid reservoir 42. It is also possible that the pressure generating unit 44 comprises a standard inflatation syringe or a standard inflation device for balloon catheters. The pressure generating unit 44 or hydraulic control device is preferably arranged externally and can be actuated mechanically.

Bezufszeichenliste

10 catheter lead

11 outer wall

12 inner wall

13 end stop

14 rejuvenation

15 pressure line

16 peak cones

17 piston section

18 end section

20 displacement unit

21 pistons

21a sealing section

21b adapter section

21c distal end

21d proximal end

22 adapters

23 undercut 24 positive locking element

25 push plate

26 locking device

27 recess

28 extension

29 graduation

29a shoulder

30 sealants

30a -proximal sealing element

30b distal sealing element

31 sealing lip

32 Radial outer area

33 joint connection

34 sealing rings

40 guidewire / guide means

41 connector

42 Fluidr e svoir

43 pressure regulator

44 pressure generating unit

45 pressure gauge

50 functional element

50a distal end

50b proximal end

51 blood vessel

52 plaque

53 patient

54 counterpart / X-ray marker

100 loader

110 introducer sheath

Claims

claims

1. A medical catheter for releasing a functional element (50), in particular an implant or a minimally invasive device, with a pressure-actuable displacement unit (20) which cooperates with the functional element (50) for release, characterized in that the displacement unit (20) comprises a piston (21) disposed in a catheter line (10) -lose and connected to the functional element (50) - connected or bated, wherein the piston (21) in use defines a pressure line (15) disposed between a proximal end of the Catheter line (10) and a proximal surface of the piston (21) is formed such that the piston (21) for releasing the functional element (50) by a pressure, in particular an overpressure and / or a negative pressure, at least partially axially displaceable relative to the catheter line is.

2. A medical catheter according to claim 1, characterized in that a distal end (50a) of the functional element (50) is arranged freely in the catheter line (10) and a proximal end (50b) of the functional element (50) with a distal end (21c ) of the piston (21) fixed or releasably connected by a locking device (26) such that by the piston (21) longitudinal forces in the distal direction of the catheter line (10) at positive pressure and longitudinal forces in the proximal direction of the catheter line (10) at negative pressure the functional element (50) is transferable to move the functional element (50) in the distal or proximal direction.

3. A medical catheter according to claim 1 or 2, characterized in that the piston (21) on a guide means, in particular on a guide wire (40), is displaceably guided.

4. Medical catheter according to at least one of claims 1 to 3, characterized in that the pressure line (15) is formed substantially free of installation.

5. Medical catheter according to at least one of claims 1 to 4, characterized in that the pressure line (15) with the catheter line (10) is integrally formed.

6. Medical catheter according to at least one of claims 1 to 5, characterized in that at an distal end of the catheter line (10) an end stop (13) is arranged.

7. A medical catheter according to claim 6, characterized in that the end stop (13) by a distal taper of the catheter line (10) is formed.

8. Medical catheter according to claim 6 or 7, characterized in that the end stop (13) comprises a rigid or flexible sleeve or spiral wire element.

9. Medical catheter according to at least one of claims 1 to 8, characterized in that the displacement unit (20) comprises at least one sealing means (30) which is connected to the piston (21) and seals against the catheter line (10).

10. Medical catheter according to at least one of claims 1 to 9, characterized in that the displacement unit (20) comprises at least one proximal sealing element (30a) which seals under the influence of a force acting in the distal direction against the catheter line (10).

11. Medical catheter according to at least one of claims 1 to 10, characterized in that the displacement unit (20) comprises at least one distal sealing element (30b) which seals against the catheter line (10) under the influence of a force acting in the proximal direction.

12. A medical catheter according to at least one of claims 9 to 11, characterized in that between the sealing means (30), in particular between the proximal sealing element (30a) and the distal sealing element (30b), a flexible hinge connection (33) is arranged.

13. The medical catheter according to claim 10, characterized in that the proximal sealing device (30a) and / or the distal sealing element (30b) comprise a cascade seal.

14. Medical catheter according to at least one of claims 9 to 13, characterized in that the sealing means (30) have an annular, flexible sealing lip (31) which is arranged in a radially outer area- (32).

15. Medical catheter according to at least one of claims 1 to 14, characterized in that the displacement unit (20) comprises an adapter (22) which is adapted for positive connection with the functional element (50).

16. A medical catheter according to claim 15, characterized in that the adapter (22) comprises an undercut (23) for receiving the functional element (50).

17. A medical catheter according to claim 15 or 16, characterized in that the adapter (22) is arranged distally of the sealing means (30).

18. Medical catheter according to at least one of claims 15 to 17, characterized in that the adapter (22) with the piston (21) is integrally formed.

19. A medical catheter according to at least one of claims 1 to 18, characterized in that the catheter line (10) has an inner diameter which is less than 2.0 mm, in particular less than 1.5 mm, in particular less than 1.0 mm, in particular less than 0.75 mm, in particular less than 0.5 mm, and / or comprises a wall thickness which is less than 0.25 mm, in particular less than 0.2 mm, in particular less than 0.15 mm, in particular less than 0.1 mm.

20. Medical catheter according to at least one of claims 1 to 19, characterized in that an inner wall (12) of the catheter line (10) with the displacement unit (20), in particular the sealing element (30), at least in sections, a dynamic coefficient of friction, the smaller or 0.35, in particular less than or equal to 0.30, in particular less than or equal to 0.20, in particular less than or equal to 0.10, in particular less than or equal to 0.09, in particular less than or equal to 0.08, in particular smaller or equal 0.07, in particular less than or equal to 0.06, in particular smaller "θthe" equal -0.05 -particularly-smaller-or-less-OjO ^, in particular -e-small & r -or-equal -0.03, in particular smaller or equal to 0.02.

21. A medical system with a catheter according to claim 1 and a pressure generating unit which is fluid-connectable to the catheter line (10), in particular to the pressure line (15), such that a pressure acting on the proximal surface of the piston (21) is adjustable.

22. Loading device (100) for the production of a medical catheter according to claim 1 with a tubular or tubular introducer sheath (HO), in which the displacement unit (20) is arranged, wherein the displacement unit (20) comprises the piston (21) with the Functional element (50), in particular an implant or minimally invasive device, permanently or detachably connected and loosely arranged in the introducer sheath (110) and wherein the introducer sheath (HO) on the one hand with a Druckz eugungseinheit and on the other hand with the catheter line (10) is connectable such that the displacement unit (20), in particular the piston (21), hydraulically and / or mechanically actuated in the catheter line (10) is insertable.