DE102009019823A1 - Medical catheter, medical system with such a catheter and charging device for producing such a catheter - Google Patents

Abstract

The invention relates to a medical catheter for releasing a functional element (50), in particular an implant or a minimally invasive device, with a pressure-actuatable displacement unit (20) which cooperates with the functional element (50) for release. The invention is characterized in that the displacement unit (20) comprises a piston (21) arranged loosely in a catheter line (10) and connected or connectable to the functional element (50), the piston (21) in use Pressure line (15) limited formed between a proximal end of the catheter line (10) and a proximal surface of the piston (21), 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. Furthermore, the invention relates to a medical system with such a catheter and a charging device for producing such a catheter.

Description

The invention relates to a medical catheter for releasing a functional element, in particular an implant or a minimally invasive device, according to the preamble of claim 1. The invention further relates to a charging device for such a catheter and a medical system with such a catheter. A medical catheter of the type mentioned is, for example, from the EP 1 208 816 A2 known.

EP 1 208 816 A2 discloses a delivery system for inserting a stent into a blood vessel, the delivery system comprising a catheter having a guide wire and an actuating fluid disposed therein. 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 feeding system has the disadvantage that by the sleeve arranged around the catheter of the cross-sectional diameter the system is relatively large. In smaller body vessels Therefore, the known system can not be used. Because the delivery system has relatively many components in the distal region of the catheter, the distal end of the catheter is comparatively rigid, so that a positioning of stents in smaller, especially curved, Vessels is difficult. Overall, the well-known Feeding a relatively complicated structure.

Another device for releasing a stent is in the EP 1 779 818 A2 described. 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. 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.

Of the Disadvantage of the known device is that by the fixedly arranged in the catheter components, the production of the device complicated and costly. Moreover, the fluid column limited to the cavity between the seals, so that the areas of the catheter, which is located outside the fluid column are, have a relatively high wall thickness to provide sufficient stability to ensure. Therefore, the known device for not suitable for use in small blood vessels.

Of the The invention is therefore based on the object, a catheter for Release of a functional element, in particular of an implant or minimally invasive device, which is a simple Structure and has high flexibility and in particular can be used in small body vessels. The invention is also based on the object, a charging device for such a catheter as well as a medical system to specify with such a catheter.

These Tasks are performed with regard to the medical catheter the subject-matter of claim 1, with regard to the medical system by the subject-matter of claim 17 and in view of that on the loading device by the subject of the claim 18 solved.

The Invention is based on the idea of a medical catheter for releasing a functional element, in particular an implant or a minimally invasive device, with a pressure actuatable device Displacement unit, which cooperates with the functional element for release, specify, wherein the displacement unit comprises a piston, the loosely disposed in a catheter line. The piston is limited in use, a pressure line between a proximal end the catheter line and a proximal surface of the piston is formed such that the piston for releasing the functional element by a pressure, in particular an overpressure and / or a negative pressure, at least in sections relative to the catheter line is axially displaceable.

The core of the invention is thus to enable the release of a functional element by a hydraulic actuation, wherein the required catheter (hydraulic micro catheter) according to the invention a relatively small number of components and thus a simple structure has. 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 guidewires. 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 controllably 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.

To over the entire length of the catheter line or the medical The catheter can achieve a high degree of flexibility Pressure line to be formed essentially free of installation. On this way, a uniform pressure transfer from proximal end of the catheter lead to the proximal surface of the piston allows.

The Pressure line can be integrally formed with the catheter line be. The catheter line is thus at least partially as Pressure line formed. In this case, the pressure line is preferably bounded by the proximal surface of the piston. That means, that the length of the pressure line or the length the catheter line section forming the pressure line, in Use varies depending on the location of the piston. The medical catheter thus preferably comprises two mutually movable Components, on the one hand, the catheter line, the sections as Pressure line is formed, and on the other hand, the displacement unit, in particular the piston, which is displaceable in the catheter line is. The piston can additionally with the functional element be connected, wherein the functional element part of the displacement unit can be. For example, the functional element may be a device for include temporary vessel opening, which is firmly connected to the piston of the displacement unit.

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

Of the End stop can be achieved by a distal taper of the catheter lead be formed. Furthermore, the end stop can be a rigid or flexible Sleeve or a spiral wire element. In this way, the end stop is easy and inexpensive produced.

Thereby The tubular catheter line can be simple and inexpensive be equipped with an end stop.

at a further preferred embodiment of the invention medical catheter, the displacement unit comprises at least one Sealant which is connected to the piston and against the Catheter tube seals to a fluid-tight boundary of the pressure line to ensure.

Preferably the displacement unit has a proximal sealing element, under the influence of a force acting in the distal direction against the Catheter tube seals. The seal is done at a Movement of the piston in the distal direction, with the length the pressure line is increased. Through the proximal sealing element is thus achieved that the generation of an overpressure in the pressure line a distal movement of the piston result Has. The proximal sealing element thus ensures the sealing of the pressure line, if in the pressure line an overpressure is produced.

Alternatively or additionally, the displacement unit may comprise a distal sealing element, 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 or generally the displacement unit is axially movable in the catheter line by generating a negative pressure in the pressure line in the proximal direction. 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.

Of the Piston can be a flexible, in particular articulated connection or have joint connection. Preferably, the flexible connection or Articulated connection between the proximal and the distal sealing element arranged. The flexible connection allows the use of the catheter in small, tightly wound vessels, because curvatures or bends of the catheter balanced become.

The proximal and / or distal sealing element include a cascade seal. For example, the cascade seal may be off multiple, preferably in series successively arranged sealants be constructed. The cascade seal allows a special efficient and safe sealing of the piston against the Catheter line.

The Sealing means may further comprise an annular, flexible sealing lip, which in a radially outer Area is arranged. In general, the sealants circular according to the inner cross section of the catheter line educated. In this case, a radially outer region be formed along the circumference as a sealing lip. By the flexible sealing lip is achieved, that the sealing of the Piston relative to the catheter line at least in one Movement direction of the piston is ensured. At the same time achieved by the flexible sealing lip that in an opposite Direction of movement of the piston the friction between sealants and catheter lead is reduced, allowing a simple and uniform Axial displacement of the piston is achieved. In particular, is through the flexible sealing lip the contact pressure of the sealant reduced to the catheter line, which has a positive effect on the breakaway torque at the initiation of the piston movement.

at a further preferred embodiment of the invention medical catheter, the displacement unit comprises an adapter, the for positive connection with the functional element is adjusted. Through the positive connection is provided a particularly simple way, the Functional element from the catheter or from the catheter line to dismiss. In particular, by the positive connection avoided that to release the functional element additional Actuators are provided.

Especially advantageous is the positive connection thereby achieved that the adapter has an undercut for receiving the Includes functional element.

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

Of the Adapter may also be integrally formed with the piston. Of the Structure of the catheter, in particular the displacement unit, thereby continues simplified and reduced production costs.

at a further preferred embodiment of the invention, medical catheter, the catheter tube has an inner diameter 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 a wall thickness which is less than 0,25 mm, in particular less than 0,2 mm, especially less than 0.15 mm, in particular less than 0.1 mm. Such a trained catheter line has a special high flexibility with small dimensions on, thereby the catheter especially in cerebral blood vessels can be used advantageously.

Of Furthermore, it is preferred if the inner wall of the catheter line with the displacement unit, in particular the sealing element, at least sectionally has a dynamic coefficient of friction, 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 smaller or is 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 less than or equal to 0.04, in particular smaller 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 easy to control, in particular haptically controlled controllable, release of the functional element. The lower limit of the Coefficient of friction can be 0.01.

According to a sibling aspect of the invention, a medical system comprises the previously described catheter and a pressure generator Delivery unit which is fluid-connectable with the catheter line, in particular with the pressure line such that the pressure acting on the proximal surface of the piston is adjustable.

One another, subsidiary aspect of the invention is based on the idea a loading device with a tube-like or tubular introducer sheath specify, in which a displacement unit is arranged, wherein the Displacement unit comprises a piston which is provided with a functional element, in particular an implant or minimally invasive device, connected and loosely arranged in the introducer sheath. The introducer sheath is on the one hand with a pressure generating unit and on the other hand connected to a catheter line such that the displacement unit for producing the previously explained Catheter hydraulically and / or mechanically actuated in the catheter tube is insertable.

The Invention will be described below with reference to exemplary embodiments with reference to the accompanying schematic drawings explained in more detail. Show in it

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

2 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 8th in each case 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 in the catheter line according to a preferred embodiment;

14 a longitudinal section through a catheter according to the invention during the release of a functional element in a blood vessel according to a preferred embodiment.

1 shows a cross section through a blood vessel 51 with a plaque 52 , The plaque 52 puts a pathological constriction of the blood vessel 51 and hinders blood flow, thus jeopardizing the nutrient supply to downstream tissue. To prevent the plaque 52 the blood vessel 51 closes further, with a medical catheter according to the embodiment described here is a functional element 50 , in particular a stent or stent-graft, inserted into the vessel section to be treated.

The medical catheter comprises a catheter line 10 which has a substantially circular cross-section. The catheter line 10 includes a flexible wall, so that the catheter line 10 is formed substantially tubular. Preferably, the catheter lead 10 made of a biocompatible, especially sterili sierbaren, plastic. At a distal end of the catheter lead 10 is an end stop 13 arranged. The clear cross-section or the inner diameter of the catheter line 10 is in the range of the end stop 13 preferably smaller than in the rest of the catheter line 10 , That means the end stop 13 annular on an inner surface 12 the catheter wall 10 is arranged. The end stop 13 may be the inner peripheral surfaces of the catheter tube 10 even partially cover. For example, the end stop 13 single, over the inner circumference of the catheter lead 10 distributed and spaced apart arranged stop elements.

Inside the catheter line 10 is a piston in use 21 arranged. The piston 21 includes according to 1 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 a seal of the sealing elements 30a . 30b against the catheter line 10 is ensured. In particular, the double conical arrangement of the sealing elements 30a . 30b ensures that a seal is ensured when the piston 21 both proximally and distally in the catheter lead 10 is moved. The piston 21 is preferably rotationally symmetrical or has a circular cross-section. At a distal end of the piston 21 is an adapter 22 arranged, which is a positive connection element 24 includes. Through the adapter 22 is the piston 21 to the functional element 50 adapted, so that the functional element 50 with the piston 21 is detachably connected. The detachable connection preferably takes place in a form-fitting manner by the positive-locking element 24 ,

The sealing elements 30a . 30b , The piston 21 and the adapter 22 and the positive-locking element 24 together form the displacement unit 20 , The displacement unit 20 is inside the catheter line 10 arranged and axially displaceable in this. The displacement can take place both in the proximal and in the distal direction. The sealing elements seal 30a . 30b against the catheter tung 10 off, leaving the displacement unit 20 one proximal to the displacement unit 20 arranged pressure line 15 limited. As a pressure line 15 So is a section of the catheter line 10 referred to, extending from a proximal end of the catheter lead 10 to a proximal end of the displacement unit 20 extends. The length of the pressure line 15 can thus in dependence of the position of the displacement unit 20 in the catheter line 10 vary.

As in 1 indicated by the designations P + and P-, is in the pressure line 15 for releasing the functional element 50 produces a higher pressure than in the blood vessel 51 is present. In this way, as indicated by the arrow in 1 represented, the displacement unit 20 moved in the distal direction, so that the functional element 50 in the blood vessel 51 is released. The procedure for positioning and releasing the functional element 50 , in particular a stent, will be later associated with the 11 to 14 explained in more detail.

To achieve that the displacement unit 20 within the catheter line 10 is held, the catheter line 10 an end stop 13 on. The end stop 13 For example, as in the longitudinal section according to 2 represented, be formed. In this case, the tip of the catheter line 10 or the catheter tip a rejuvenation 14 on, reducing the internal diameter of the catheter tube 10 is reduced. The rejuvenation 14 connects a piston section 17 in which the piston 21 or the displacement unit 20 is arranged, with an end portion 18 , An outer wall 11 the catheter line 10 extends substantially straight across the entire catheter line 10 and also forms in the region of the end section 18 a peak bonus 16 , The catheter line 10 Thus, at a distal end has a cone-shaped tip, ie the tip cone 16 , on. 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 area of the piston section 17 includes the catheter lead 10 also an additional inner wall 12 that with the outer wall 11 is firmly connected. The outer wall 11 and the inner wall 12 preferably differ by material properties. In particular, the inner wall 12 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 for the inner wall 12 used. The surface modification can be done at the molecular level. For example, the inner wall 12 Polyurethane or Pebax, with a relatively high Shore hardness of the material is appropriate. Preferred is a Shore hardness of at least 72 D. Both the inner wall 12 or inner sliding surface of the catheter line 10 , as well as the sealants 30 may include such materials, especially surface modified plastics.

In the field of rejuvenation 14 is also the end stop 13 arranged. The end stop extends 13 also partially in the end section 18 , The end stop 13 preferably comprises a material having a higher rigidity than the catheter lead 10 , in particular the outer wall 11 , For example, the end stop 13 a sleeve made of metal or plastic. Alternatively, it is possible that the end stop 13 a spiral sleeve or a spiral wound wire element, which is arranged like a spring in the catheter tip and increases the flexibility of the catheter tip. The end stop 13 can at least partially comprise a radiopaque material to the positioning of the catheter or the catheter line 10 in a body vessel to facilitate.

In the 3 to 8th are different variants of the displacement unit 20 shown. In general, the displacement unit comprises 20 the piston 21 which is preferably coaxial with the catheter line 10 is arranged. In a proximal section of the piston 21 are sealants 30 arranged. The sealants 30 are with the piston 21 firmly connected. The proximal section or sealing section 21a of the piston 21 is preferably by a push plate 25 limited or from a distal section or adapter section 21b separated. The push plate 25 has a cross-sectional diameter that is smaller than the inner diameter of the catheter tube 10 is. This ensures that the contact between the displacement unit 20 and catheter lead 10 only through the sealant 30 he follows. The sealants 30 thus limit the pressure line 15 or the pressure line section of the catheter line 10 ,

According to 3 has the displacement unit 20 several dish-shaped sealants 30 on. In each case, three sealants form 30 a cascaded, proximal sealing element 30a and a cascaded, distal sealing element 30b , The proximal sealing element 30a and the distal sealing element 30b are spaced from each other. The plate-like sealants 30 further comprise a radially outer region 32 , of the has a relatively high flexibility and a sealing lip 31 forms. Due to the high flexibility of the sealing lip 31 or the radially outer region 32 becomes the secure seal of the sealant 30 against the catheter line 10 , in particular the low-friction inner wall 12 , reached. The curvature of the plate-like sealant 30 is according to 3 aligned or formed in the distal direction. This ensures that by an overpressure in the pressure line 15 is generated, on the one hand, the movement of the displacement unit 20 in the distal direction and on the other hand, the sealing of the sealant 30 against the catheter line 10 he follows. The displacement unit 20 is thus due to the arrangement of the sealing elements 30 for the distal displacement of the displacement unit 20 designed as indicated by the arrow in 3 shown schematically.

A two-sided displacement of the displacement unit 20 Thus, a displacement in the distal and in the proximal direction, for example, allows the seal assembly according to 4 , The structure of the displacement unit 20 according to 4 corresponds essentially to the structure of the displacement unit 20 according to 3 , with the difference that the cascade-like, distal sealing element 30b is arranged offset. The plate-like sealants 30 of the distal sealing element 30b thus have a proximally directed curvature. In this way, the sealants seal 30 of the distal sealing element 30b during movement of 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 For example, by generating a negative pressure in the pressure line 15 , In addition, according to 4 provided between the proximal sealing element 30a and the distal sealing element 30b a flexible joint 33 to arrange. The flexible joint 33 is shown schematically in the figures by a filled circle. Due to the flexible hinge connection 33 is achieved that the flexibility of the displacement unit 20 is increased, so that the displacement unit 20 a curvature of the catheter lead 10 can follow.

5 shows the displacement unit 20 according to 4 , wherein in the adapter section 21b of the piston 21 a functional element 50 is arranged. The functional element 50 can with the adapter section 21b or the adapter 22 be releasably or firmly connected. A detachable connection is especially in functional elements 50 advantageous, which are designed as stents or generally as implants. Such functional elements 50 remain after positioning in the body. Alternatively, the functional element 50 a microsurgical instrument, such as a thrombosis trap or retriever include. Here is the functional element 50 preferably firmly with the adapter 22 connected. The connection can be positive or non-positive. For example, the functional element 50 on the adapter 22 be crimped. It is also possible that the adapter 22 includes an undercut that with the functional element 50 cooperates with the positive connection. Another possibility for positive connection form, for example, X-ray markers, either the adapter 22 or the functional element 50 assigned. This can be the adapter 22 be adapted to accommodate standard functional elements, such as standardized implants such as stents or stent-grafts. Alternatively, the structure of the functional element 50 to the displacement unit 20 , especially the adapter 22 be adapted. For example, corresponding implants may have loops, cells or other geometric properties that provide a firm or detachable connection to the adapter 22 enable. Alternatively, the connection between functional element 50 and adapters 22 cohesively, for example by gluing, welding or soldering done.

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

Another embodiment of a displacement unit 20 shows 6 , In this case, the displacement unit 20 a piston 21 on that through the push plate 25 in the sealing section 21a and the adapter section 21b is divided. In the sealing section 21a are sealants 30 arranged, each with two sealants 30 the proximal sealing element 30a or the distal sealing element 30b form. The proximal sealing element 30a and the distal sealing element 30b are by a flexible, indicated by the filled circle joint 33 connected. The sealants 30 according to 6 are annular or disc-shaped and have in a radially outer region 32 a rounding on, leaving the sealant 30 in both directions of movement of the displacement unit 20 a reliable seal against the catheter line 10 , in particular the inner wall 12 , guarantee. In the adapter section 21b the displacement unit 20 is the functional element 50 arranged. Through another filled circle in the adapter section 21b is a Form-fitting element 24 indicated that the connections between functional element 50 and displacement unit 20 allows.

A similar embodiment shows 7 , In contrast to the embodiment according to 6 has the displacement unit 20 according to 7 a piston 21 on, which includes a much larger cross-sectional diameter than the piston 21 according to 6 , The sealants 30 are preferably formed as O-rings, which are fixed on the piston 21 , in particular in the sealing section 21a , are arranged. A total of four O-rings are provided, each with two O-rings, the proximal sealing element 30a or the distal sealing element 30b form. Between the proximal sealing element 30a and the distal sealing element 30b is a flexible hinge connection 33 arranged.

Another variant of the displacement unit 20 shows 8th , The adapter section corresponds to this 21b of the piston 21 with the push plate 25 essentially in accordance with the exemplary embodiment 7 , In the sealing section 21a is an alternative sealant 30 arranged. The sealant 30 engages over the proximal end of the piston 21 essentially complete and pointing in a radially outer area 32 a sealing lip 31 on at a distal portion of the sealant 30 is articulated. The sealing lip 31 extends in the axial direction over the proximal end of the piston 21 out and is preferably cone-shaped, so that the sealing lip 31 at least at its proximal end with the inner wall 12 the catheter line 10 comes into contact. Preferably, the sealing lip 31 designed as a play compensation lip. This in 8th sealant shown 30 provides a reliable seal of the displacement unit 20 opposite the catheter line 10 during a movement of the displacement unit 20 in the distal direction, as indicated by the arrow in 8th indicated.

The operation of the medical catheter is described below with reference to 9 to 14 explained in more detail:
To treat a plaque 52 or generally a lesion in a blood vessel 51 first becomes a guidewire 40 in the blood vessel 51 introduced and advanced to the treatment site, as in 9 shown. The guidewire 40 may include a conventional guide wire or guide wire.

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

11 shows that the guidewire 40 in a subsequent step from the blood vessel 51 and the microcatheter or catheter tubing 10 Will get removed.

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

A loading device 100 includes an introducer sheath 110 in which the displacement unit 20 is arranged axially displaceable. Further, in the introducer sheath 110 the functional element 50 arranged. The functional element 50 is according to 12 with the displacement unit 20 positively connected. This is the adapter 22 the displacement unit 20 as form-fit adapter or positive-locking element 24 educated. To the displacement unit 20 into the catheter line 10 introduce the charging device 100 or the introducer sheath 110 with the connector 41 connected so that the introducer sheath 110 coaxial to the catheter line 10 is arranged. In a proximal section of the introducer sheath 110 by the displacement unit 20 is limited, a pressure, in particular overpressure is generated, so that the displacement unit 20 into the catheter line 10 is pushed into it. In this case, both the microcatheter and the catheter line 10 , as well as the introducer sheath 110 filled with a saline solution. The saline solution serves as pressure fluid for advancing the displacement unit 20 , In terms of construction and handling, the introducer sheath corresponds 110 So essentially the catheter line 10 , It is not excluded that the transfer of the displacement unit 20 from the introducer sheath 110 into the catheter line 10 at least partially mechanical. For example, it is possible that the displacement unit 20 mechanically from the introducer sheath 110 in the previously flushed, ie filled with fluid, catheter line 10 is moved. In a further step, the introducer sheath 110 removed and in place of the pressure generating unit 44 with the catheter line 10 connected to the movement of the displacement unit 20 in the catheter line 10 hydraulically controlled.

Once the displacement unit 20 in the catheter line 10 is arranged, the charging device 100 or the introducer sheath 110 Disconnected and a pressure generating unit 44 with the connector 41 connected. The pressure generating unit 44 preferably comprises a pressure regulator 43 and a pressure gauge 45 , The connection of the pressure generating unit 44 with the connector 41 via a fluid reservoir 42 that is the supply of liquid in the pressure line 15 or the pressure line section of the catheter line 10 guaranteed. With the pressure generating unit 44 can in the pressure line 15 both an overpressure for advancing the displacement unit 20 , as well as a negative pressure for retracting the displacement unit 20 be generated. The interaction of the catheter line 10 or the displacement unit 20 with the pressure generating unit 44 is in 13 shown.

As in 14 shown causes overpressure generation by the pressure generating unit 44 an increased fluid pressure in the pressure line 15 , This means that 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 by the feed of the displacement unit 20 displaced into the blood vessel. As in 14 shown, becomes the functional element 50 into the area of plaque 52 advanced. Here is the catheter line 10 positioned such that the distal end of the catheter lead 10 or the catheter tip distal to the plaque 52 is arranged.

The release of the functional element 50 , here a stent, preferably takes place as in 1 shown. This is the catheter line 10 retracted in the proximal direction and by corresponding hydraulic pressure in the pressure line 15 the displacement unit 20 kept essentially stationary. In this way, the functional element becomes 50 from the catheter line 10 dismisses and expands automatically. Once the displacement unit 20 the end stop 13 has achieved, the positive connection between the functional element 50 and displacement unit 20 or adapter 22 solved, so that the functional element 50 , especially the stent, completely in the blood vessel 51 is released. 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 the functional element 50 into the catheter line 10 to pull back. This may be appropriate to an exact positioning of the functional element 50 to reach.

• – Hohe Flexibilität im distalen Bereich für eine verbesserte Zielerreichbarkeit insbesondere in kleinen Arterien mit weniger als 2 mm Durchmesser,
• – Hohe Flexibilität beim Zuführen der Katheterleitung 10, da innerhalb der Katheterleitung 10 in diesem Verfahrensschritt keine Bauteile angeordnet sind,
• – Reduktion der Belastung der Gefäße bzw. Gefäßwände durch seitlichen Druck, da die Fluidsäule der Druckleitung 15 der Gefäßkrümmung folgt,
• – Einfach handhabbare, genaue und gleichmäßige Steuerung des Freisetzprozesses,
• – Geringe Knickgefahr und wenig Faltenbildung,
• – Geringe Anzahl an Bauteilen, so dass Kosten und Komplexität reduziert sind,
• – Geringe Reibung innerhalb der Katheterleitung 10, da eine kompakte Bauweise der Verschiebeeinheit 20 möglich ist.

Overall, the medical catheter according to the invention 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 when feeding the catheter line 10 because inside the catheter line 10 in this process step, no components are arranged,
• - Reduction of the load on the vessels or vessel walls by lateral pressure, since the fluid column of the pressure line 15 the vessel curvature follows,
• - Easy to handle, accurate and uniform control of the release process,
• - Low risk of buckling and little wrinkling,
• - Low number of parts, reducing costs and complexity,
• - Low friction within the catheter line 10 , as 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. In particular, closed-cell stents and braided stents can, if necessary, by applying a negative pressure in the pressure line 15 back into the catheter line 10 be withdrawn. Furthermore, the catheter according to the invention can be used for releasing filters, baskets or retrievers. Such functional elements 50 are preferably fixed to the adapter 22 connected and are after use back into the catheter line 10 withdrawn.

Especially suitable is the inventive medical Catheters for the treatment of lesions in cerebral blood vessels, which have a small relatively small cross-sectional diameter, because the catheter according to the invention is relatively small can be dimensioned. This is possible because on guide wires or Stabilizer and similar components are omitted can.

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

The pressure piston or the piston 21 preferably has a flexible body or a flexible axis, so that the piston 21 or overall the displacement unit 20 Curvatures of the catheter line 10 can follow. The piston 21 can also consist of several coupled cells or sections.

The adapter section 21b of the piston 21 may be a flexible coil, a nitinol wire, or one for connection to the functional element 50 have appropriate geometry.

Overall, the invention is based on the basic idea, a freely movable, loosely arranged displacement unit 20 in a catheter line 10 or to arrange a microcatheter, the one from the user to the displacement unit 20 limited fluid pressure column. The user can access the sliding unit 20 only act 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. That does not exclude that the displacement unit 20 for example, when loading the catheter line 10 is mechanically operated. The loose arrangement of the displacement unit 20 means within the scope of the invention that the displacement unit 20 essentially axially freely movable in the catheter line 10 is arranged, wherein the movement of the displacement unit 20 through the fluid column in the pressure line 15 is controllable. The control is carried out by the pressure generating unit 44 , In this case, the pressure generating unit 44 preferably the fluid reservoir 42 include. It is also possible that the pressure generating unit 44 a standard Inflatationssitze or a standard Inflatationsgerät for balloon catheter includes. The pressure generating unit 44 or hydraulic control device is preferably arranged externally and mechanically actuated.

10

catheter line

11

outer wall

12

inner wall

13

end stop

14

rejuvenation

15

pressure line

16

tip cone

17

piston section

18

end

20

displacement unit

21

piston

21a

sealing section

21b

adapter section

22

adapter

23

undercut

24

Form-fitting element

25

pusher plate

30

sealant

30a

proximal sealing element

30b

distal sealing element

31

sealing lip

32

Radially outer Area

33

articulation

40

guidewire

41

connector

42

fluid reservoir

43

pressure regulator

44

Pressure generating unit

45

pressure gauge

50

functional element

51

blood vessel

52

plaque

 53

patient

100

loader

110

introducer

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - EP 1208816 A2 [0001, 0002]
• - EP 1779818 A2 [0004]

Claims (20)

Medical catheter for releasing a functional element ( 50 ), in particular an implant or a minimally invasive device, with a pressure-actuable displacement unit ( 20 ) connected to the functional element ( 50 ) cooperates to release, characterized in that the displacement unit ( 20 ) a piston ( 21 ) contained in a catheter line ( 10 ) and with the functional element ( 50 ) is connected or connectable, wherein the piston ( 21 ) in use a pressure line ( 15 ) defined between a proximal end of the catheter tube ( 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. Medical catheter according to claim 1, characterized in that the pressure line ( 15 ) is formed substantially free of installation. Medical catheter according to claim 1 or 2, characterized in that the pressure line ( 15 ) with the catheter line ( 10 ) is formed in one piece. Medical catheter according to at least one of claims 1 to 3, characterized in that at a distal end of the catheter line ( 10 ) an end stop ( 13 ) is arranged. Medical catheter according to claim 4, characterized in that the end stop ( 13 ) by a distal taper of the catheter line ( 10 ) is formed. Medical catheter according to claim 4 or 5, characterized in that the end stop ( 13 ) comprises a rigid or flexible sleeve or spiral wire element. Medical catheter according to at least one of claims 1 to 6, characterized in that the displacement unit ( 20 ) at least one sealant ( 30 ) connected to the piston ( 21 ) and against the catheter line ( 10 ) seals. Medical catheter according to at least one of claims 1 to 7, characterized in that the displacement unit ( 20 ) at least one proximal sealing element ( 30a ) under the influence of a force acting in the distal direction against the catheter line ( 10 ) seals. Medical catheter according to at least one of claims 1 to 8, characterized in that the displacement unit ( 20 ) at least one distal sealing element ( 30b ) under the influence of a force acting in the proximal direction against the catheter line ( 10 ) seals. Medical catheter according to at least one of claims 7 to 9, characterized in that between the sealing means ( 30 ), in particular between the proximal sealing element ( 30a ) and the distal sealing element ( 30b ) a flexible joint connection ( 33 ) is arranged. Medical catheter according to at least one of claims 8 to 10, characterized in that the proximal sealing element ( 30a ) and / or distal sealing element ( 30b ), comprise a cascade seal. Medical catheter according to at least one of claims 7 to 11, characterized in that the sealing means ( 30 ) an annular, flexible sealing lip ( 31 ), which in a radially outer region ( 32 ) is arranged. Medical catheter according to at least one of claims 1 to 12, characterized in that the displacement unit ( 20 ) an adapter ( 22 ), which for the positive connection with the functional element ( 50 ) is adjusted. Medical catheter according to claim 13, characterized in that the adapter ( 22 ) an undercut ( 23 ) for receiving the functional element ( 50 ). Medical catheter according to claim 13 or 14, characterized in that the adapter ( 22 ) distal to the sealant ( 30 ) is arranged. Medical catheter according to at least one of claims 13 to 15, characterized in that the adapter ( 22 ) with the piston ( 21 ) is formed in one piece. Medical catheter according to at least one of claims 1 to 16, 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 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. Medical catheter according to at least one of claims 1 to 17, characterized in that an inner wall ( 12 ) of the catheter tion ( 10 ) with the displacement unit ( 20 ), in particular the sealing element ( 30 ), at least in some sections 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 less than or equal to 0.04, in particular less than or equal to 0.03, in particular smaller or equal to 0.02. A medical system with a catheter according to claim 1 and a pressure generating unit connected to the catheter line ( 10 ), in particular with the pressure line ( 15 ), is fluid-connectable such that one on the proximal surface of the piston ( 21 ) acting pressure is adjustable. Loading device ( 100 ) for producing a medical catheter according to claim 1 with a tube-like or tubular introducer sheath (US Pat. 110 ), in which the displacement unit ( 20 ), wherein the displacement unit ( 20 ) the piston ( 21 ) associated with the functional element ( 50 ), in particular an implant or minimally invasive device, fixed or detachably connected and in the introducer sheath ( 110 ) and wherein the introducer sheath ( 110 ) on the one hand with a pressure generating unit 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 into the catheter line ( 10 ) is insertable.