WO2009132858A2

WO2009132858A2 - Device for removing concretions from body vessels

Info

Publication number: WO2009132858A2
Application number: PCT/EP2009/003188
Authority: WO
Inventors: Giorgio Cattaneo; Michael BÜCHERT
Original assignee: Acandis Gmbh & Co. Kg
Priority date: 2008-05-02
Filing date: 2009-05-04
Publication date: 2009-11-05
Also published as: DE102008059547A1; WO2009132858A3; DE102008059547B4; EP2273930A2

Abstract

The invention relates to a device for removing concretions from body vessels, comprising at least one compressible receiving element (20) for receiving concretions and a supply device (10) for guiding the compressed receiving element (20). The invention is characterized in that the receiving element (20) comprises a fluid-tight cover (21) which forms a, particularly proximal, hollow space (30a) that can be closed by the concretion to be removed. According to the invention, an actuation device (11) is assigned to the receiving element (20), which during use is in operative connection with the cover (21) and/or the hollow space (30a) such that a different pressure can be set inside the hollow space (30a) than outside said hollow space (30a) for moving, particularly detaching, the concretion to be removed.

Description

Device for removing concrements in body vessels

description

The invention relates to a device for removing concrements from body vessels according to the preamble of claim 1. Such a device is known for example from WO 2006/031410.

The formation of concrements in body vessels can lead to the body vessel being completely or at least partially closed by the concrement, with the consequence of considerable health restrictions. A particularly high risk is assumed by thrombi, i. Blood clots that form intravascularly and may partially or completely occlude the blood vessel. When the occlusion concerns an artery, the downstream tissue areas are no longer or inadequately supplied with oxygen and other nutrients, which is termed ischemia, and may result in tissue death.

Currently, thrombi in human arteries are usually treated by drug thrombolysis, whereby the blood clots are dissolved by means of drugs. The condition for this therapy is that the treatment takes place no later than three hours after the appearance of the symptomatology. In addition to this narrow time window, drug thrombolysis has the disadvantage that the treatment not only acts locally in the area of the thrombus, but also in other areas, for example in nearby brain areas. Due to the inhibition of blood clotting is the Danger of bleeding complications, in particular the risk that the therapy causes cerebral hemorrhage.

An alternative to drug therapy is the mechanical removal of thrombi from blood vessels, in which, for example, a device according to the aforementioned WO 2006/031410 Al is used. The known device comprises a receiving basket with a stent-like lattice structure arranged for insertion into the blood vessel in a compressed state within a catheter. To remove the blood clot, the catheter is inserted into the blood vessel until the catheter tip is positioned near the thrombus. The receiving basket located in the catheter is released at the catheter tip and unfolds there to about the size of the blood vessel so that the thrombus can be received by the basket. The catheter is also designed as an aspiration catheter, which generates a negative pressure in the area in front of the thrombus, so that parts of the thrombus are detached and sucked into the catheter. The receiving basket additionally serves as a filter so that no larger particles are transported past the aspiration catheter into further blood vessels.

In the known device, a relatively large area is subjected to a negative pressure by the aspiration in the area in front of the thrombus. The pressure in a larger brain area drops below the physiological pressure and there is a risk that the transmural pressure will be negative. This can result in the blood vessel being narrowed or collapsed in front of the thrombus, so that the blood flow in this area is limited or comes to a complete standstill. This prevents efficient detachment of the thrombus on the one hand and risks the vessel being injured by the effect of the negative transmural pressure on the other hand. In particular, when the negative pressure in vessel areas with branching secondary vessels acts, there is a risk that the secondary vessels collapse and thus previously well-perfused tissue areas are inferior. Even with positive transmural pressure, aspiration-induced negative pressure, ie, pressure less than physiological pressure, results in reduced perfusion of the affected areas, particularly in the brain. Another problem when using the known device results in cases when the thrombus to be solved does not close the entire vessel cross section, so that still partially a Biutdurchfluss is possible. Such a situation can arise, for example, in that parts of the thrombus have already been removed by the aspiration, so that the vessel is partially recanalized, ie reopened. There is a risk that the blood now flowing past the catheter and through the receiving basket when it passes through the thrombus entrains particles which can lead to a renewed occlusion in smaller blood vessels located further downstream. To counteract this process, it is known to increase the aspiration volume, so that the entire, flowing through the blood vessel blood is sucked. In this case, the patient is taken in a relatively short period of time, a large amount of blood volume, which can have significant health consequences for the patient.

Particle detachment with subsequent closure of downstream vessels may occur, in particular, when a relatively large particle is released from the thrombus by aspiration, aspirated by the catheter, and the suction opening is thereby closed. In this case, the generation of the negative pressure is suddenly interrupted, so that the original pressure conditions in the blood vessel are restored. The re-forming blood flow can detach other particles and transport them to downstream vessels, which can lead to a renewed vascular occlusion.

The invention is based on the object to provide a device for removing concrements from body vessels, which ensures easy and safe handling and function and reduces the health risks to the patient.

According to the invention, this object is achieved by the subject matter of patent claim 1. Alternatively, this object is achieved by the subject matter of the independent patent claim 19.

The invention is based on the idea of a device for removing concrements from body vessels with at least one compressible receiving element for receiving concrements and a supply device for guiding the Kompri- The receiving element has a fluid-tight cover, which forms a closable by the concrement to be removed, in particular proximal cavity, wherein the Aufnahmeeiement an actuating device is assigned, which is at least in use with the cover and / or the cavity in operative connection in that a different pressure can be set in the cavity for moving, in particular for releasing the concretion to be removed, than outside the cavity, in particular on the distal side of the concretion to be removed.

The invention has the advantage that the concretion is sucked by setting a lower pressure in the cavity as the physiological pressure (negative pressure) in the cavity or the receiving element or pushed by the force acting on the concretion higher physiological pressure in the cavity. In this respect, a force acting in the direction of the receiving element (caused by the pressure difference on both sides of the concretion) is generated on the calculus to be removed by the actuating device. It is also possible that at least temporarily the pressure gradient is reversed such that in the cavity an overpressure, i. a pressure higher than the physiological pressure is generated, so that the calculus for release is briefly acted upon by a force acting in the distal direction. For sucking the concretion in the receiving element, a negative pressure in the cavity is then set again.

To form the cavity, the receiving element delimits a space open in the axial direction, in particular in the distal axial direction, which in use can be closed by the calculus to be removed. The limitation of the space, or cavity in the other axial direction, in particular in the proximal axial direction is effected by the fluid-tight cover. In this case, the fluid-tight cover is adapted, or extends so far in the distal direction of the receiving element, that the cover with the vessel wall in fluid-tight manner in use. As a result, the vessel is sealed in one direction, in particular in the proximal direction. The seal in the other direction, in particular in the distal direction is taken over by the calculus, which rests against the vessel wall and closes the vessel. For the closure of the cavity by the concretion, it is not necessary that the concretion is applied directly to the sealed receiving element. It is sufficient if the cross-section of the receiving element downstream vessel portion and thus the cross-sectional area of the distal opening of the receiving element is covered by the calculus, wherein the concretion can be arranged slightly spaced from the receiving element. A hermetic closure of the concretion is not required to build up the pressure differential between the distal and proximal sides of the calculus. It is sufficient if the amount of blood possibly flowing through the concretion is so small that pressure equalization with a time delay occurs.

In the context of the application, cavities are generally spaces that are formed by an interaction of the calculus to be removed with the receiving element or the fluid-tight cover and that are substantially free from installation and sealed in a fluid-tight manner. In this way, the cavity can form a receiving function for the concretion and / or a sealed area in which a pressure can be set relative to the surroundings. The cavity may contain liquid, in particular blood.

In the context of the present application, the term pressure is understood to mean not only positive pressures (overpressure) but also explicitly negative pressures (negative pressure). In this case, an overpressure is a pressure which is higher than the pressure prevailing in the vessel. Accordingly, a negative pressure is a pressure which is lower than the pressure prevailing in the vessel. In the possible collapse of the vessel occurring in the prior art, the negative pressure is so pronounced that the transmural pressure is negative.

The invention is particularly suitable for removing clots or thrombi from blood vessels. Although the invention is described below using the example of the removal of thrombi, other possible uses of the device, which relate to the removal of concretions or objects from body cavities, are also encompassed by the invention. The space designations or directions, in particular the designations distal and proximal, refer to the position of the user, in particular the physician who operates the device. Distally arranged objects are accordingly arranged further away from the user or operator of the device with respect to a proximally arranged object.

The invention has the advantage that in use by the fluid-tight cover, the generation of the pressure before the calculus is locally restricted, i. that the pressure acts only in the region of the cavity, in particular the proximal cavity. In order to move the calculus or thrombus into the receiving element, the cavity is preferably filled with a negative pressure, i. a pressure lower than the blood pressure behind the thrombus is applied, wherein it is not ruled out that the pressure inside the cavity can at least temporarily also be greater than outside the cavity (overpressure). At the same time, the vessel wall is supported by the receiving element expanded in the vessel, so that vessel collapse is avoided or prevented. Furthermore, it is achieved by the closed, in particular proximally arranged cavity, that in generating the pressure by Fluidver shift only the volume is added or removed, which is necessary for movement of the thrombus in the receiving element. The removal of relatively high blood volume is thus avoided. Outside the cavity, in particular proximal to the cavity, the blood pressure is not reduced, so that the vessel collapse and a possible undersupply of brain areas is prevented.

Due to the fluid-tight cover of the receiving element of the thrombus is substantially separated from the blood flow, ie that in the cavity, in particular the proximal cavity substantially no flow is present. This avoids that stress in the cavity caused by the pressure generation in the cavity thrombus, which can lead to the detachment of individual Thrombuspartikeln. Rather, it is achieved by the pressure generated in the cavity that the thrombus is completely dissolved and moved into the receiving element, since the same pressure gradient acts on the entire cross-sectional area of the thrombus and thereby the thrombus slides homogeneously into the receiving element. Overall, the invention makes use of the per se negative effect of a vascular closure in that the closure is used in conjunction with the device according to the invention to create a pressure or vacuum loadable cavity in the vessel, which serves to release the closure and to remove the closure body. The receiving element corresponds in its function to a suction bell, ie the receiving element is designed in the manner of a suction bell.

In a preferred embodiment of the device according to the invention, the actuating device comprises a suction and / or pressure device, which is fluid-connected or fluid-connectable to the cavity. The suction and / or pressure device preferably comprises a pressure-generating unit which is fluid-connected or fluid-connectable to the cavity by a pressure line, the pressure line being arranged in or outside the feed device or formed by the feed device itself. With the suction and / or pressure device, in particular with the pressure generating unit, the pressure within the cavity, in particular of the proximal cavity can be changed particularly easily compared to the pressure outside the proximal cavity, for example by supply and / or removal of liquid or other fluids ,

In this context, it should be noted that the term fluids in the context of the present application refers not only to liquids, but also to gases.

Preferably, the actuating device comprises an actuating medium, in particular a liquid which is at least partially pumpable into the cavity, in particular proximally arranged cavity and / or sucked out of the cavity. With the actuating medium, the pressure generation in the cavity can be easily controlled by a user from outside the body. It is also conceivable that the actuating medium comprises mechanical components.

In the following, further structural features of the invention will be described, wherein the description refers to the device in use or in the expanded state of the receiving element. The receiving element may be formed like a basket. The receiving element may further comprise a distal, substantially cylindrical portion which comprises an opening for receiving a concretion. The opening forming portion of the basket-like receiving element may also have a different contour. In use, the cylindrical portion, which may be formed substantially in the manner of a stent, on the vessel wall, whereby sufficient space and stability is ensured, on the one hand to receive the blood clot or the thrombus and on the other hand to stabilize the blood vessel so that the pressure generated in the cavity does not lead to collapse of the blood vessel. The opening for receiving the thrombus is preferably arranged at the distal end of the receiving element and has approximately the diameter of the blood vessel, so that the blood clot can be received in one piece. It is possible that the cylindrical portion has a cutting region in the region of the opening, with which the release of the thrombus can be assisted.

Furthermore, the receiving element may have a proximal, substantially funnel-shaped section, which is connected to the actuating device, in particular the suction and / or pressure device. The funnel shape of the proximal end of the receiving element has the advantage that the receiving element, when it has received a thrombus, can be easily withdrawn into a catheter, wherein the receiving element is compressed. The recorded thrombus is held firmly in the receiving element and withdrawn together with this for final removal in a catheter.

In a preferred embodiment of the device according to the invention, the cover of the receiving element with the actuating device, in particular the pressure line, terminates in a fluid-tight manner. In this way it is ensured that the pressure generated acts only within the cavity, in particular the proximal cavity on the clot. In particular, when using fluids to generate a negative pressure prevents, for example, blood is pumped out of the surrounding blood vessels. Rather, for example, a negative pressure in the proximal cavity can be achieved by pumping a minimum volume of fluid. The receiving element is preferably assigned a closing element, in particular a screen, which in use can be positioned distally to a concretion. The closure member may act as a filter to prevent particles that may be releasing from the thrombus from being flushed into downstream vessels. Furthermore, the receiving element, in particular the opening of the receiving element, can be closed with the terminating element as soon as the concrement or the thrombus is arranged in the receiving element. Thus, the thrombus can be substantially completely encapsulated in the receiving element.

The closure member may comprise a fluid-tight cover adapted to form a distal cavity in cooperation with at least the concretion. This embodiment is particularly suitable for combination with the closable proximal cavity, which is formed by the fluid-tight cover of the receiving element. This has the advantage that a safety function is achieved in the event that the concretion does not close the proximal cavity so tightly that a negative pressure in the proximal cavity can be established. This could be the case, for example, when a part of the thrombus loosens and thus forms a larger channel, which creates a pressure equalization in the proximal cavity. In this regard, it should be noted that a completely tight closure of the cavity, in particular of the proximal cavity by the concretion is not required to produce the negative pressure, as long as the channels or openings present in the thrombus are so small that at least temporarily a sufficiently high pressure gradient is adjustable between the proximal and distal sides of the thrombus or concretion.

The embodiment described above has the advantage that - in the event that a sufficient pressure gradient is not achievable, the closing element or its fluid-tight cover takes over the sealing function, so that prevents a larger amount of blood from the distal side of the concretion is sucked. In addition, this embodiment has the advantage that the physiological pressure then acts on the closure element or its fluid-tight covering serving as closure element, whereby a force directed in the proximal direction on the closure element is generated, which pushes the closing element together with the concretion in the direction of the receiving element.

Advantageously, the end element with the pressure line, which is associated with the receiving element, or another, separate pressure line fluidly connected such that in the distal cavity for moving, in particular for releasing the concretion, a different pressure is adjustable than outside the distal cavity. The advantages described in connection with the proximal cavity, which is formed by the cover of the receiving element and at least the concretion, apply substantially equally to the closing element provided with the cover. In particular, this embodiment has the advantage that, by setting an overpressure in the distal cavity between the concretion and the closing element, the thrombus or, in general, the concretion is displaced in the direction of the receiving element. In contrast, in the case of the proximal cavity between the calculus and the receiving element, the movement of the concretion towards the receiving element is initiated by the negative pressure generated in the proximal cavity. In addition, in this embodiment, the overpressure created in the distal cavity results in a radial vessel widening, thereby facilitating the disengagement of the clot. Further, the removal of the clot may be assisted by anticoagulant drugs, such as thrombolytic agents, which are introduced into the distal cavity. The medication can be supplied through the pressure line.

In a preferred embodiment of the device according to the invention, the closing element and the receiving element are in fluid communication with the actuating device, in particular the suction and / or pressure device such that between the distal cavity and the proximal cavity for moving, in particular for releasing, one between the Cavities arranged concrements different, in particular changeable, relative pressures are adjustable. Decisive for the release of the thrombus is the pressure gradient, which forms between the pressure in the distal cavity and the pressure in the proximal cavity, ie via the concretion. The relative pressures in the two cavities are therefore adjustable so that, for example, a relatively high pressure can be generated in the distal cavity and a relatively low pressure in the proximal cavity in order to move the clot into the receiving element. Thereby the pressure gradient and thus the force acting on the clot to release and move is increased. In the cavities in each case an overpressure or underpressure can be generated independently of each other. In particular, it is possible to generate an excess pressure by supplying liquid in the proximal cavity and to create a negative pressure by removing fluid in the distal cavity. As a result, the thrombus moves in the distal direction, resulting in a proximal vessel widening due to the overpressure in the proximal cavity, which makes possible the detachment of the thrombus. A pressure reversal and thus a reversal of motion may follow.

The closing element and the receiving element can be connected to a common pressure generating unit. In this way, the pressure gradient necessary to release the clot can be adjusted centrally.

Preferably, the common Druckz eugungseinheit is arranged extracorporeally and comprises at least one oscillatable partition, in particular pressure membrane, which is at least in use with the closing element and / or the receiving element fluidly connected or fluid-connected. Through the pressure membrane, the pressure in the cavities can be easily and accurately adjusted and varied. For this purpose, the overpressure or negative pressure in the proximal and distal cavities on both sides of the concretion can be generated in a simple manner by liquid supply (overpressure) or liquid removal (negative pressure). Instead of the oscillatable pressure membrane, a simple syringe may also be used to intuitively control fluid delivery and drainage, whereby the physician can manually control the force and frequency required to disengage the thrombus by alternately pulling and pushing the syringe. It is therefore generally disclosed in this context that the common pressure generating unit, for example the syringe or another piston / cylinder arrangement is arranged extracorporeally. The pressure membrane or the syringe also have the advantage that the pressure in both cavities is changeable depending on each other. In particular, in this way a negative pressure can be generated in one cavity and, at the same time, an overpressure can be generated in the other cavity, wherein this pressure gradient is easily and quickly reversible or invertible. Alternatively, the common pressure generating unit may comprise a feed pump, in particular an intracorporeal feed pump, which is arranged inside the pressure line such that the feed pump is at least in use fluid-connected or fluid-connectable to the closure element and / or the receiving element. As a result, the volume of fluid to be moved to generate pressure is reduced compared with an extracorporeal pump, since the essentially ineffective dead volume present in the pressure line is not moved. The intracorporeal delivery pump is therefore particularly efficient. Another advantage of the feed pump is that there are no liquids in the feed system, only power cables or a pump shaft. This has the advantage that the system can be dimensioned with very small diameters.

The pressure generating unit, in particular the common pressure generating unit, is preferably assigned a control unit which is adapted such that a pressure change in at least one, in particular two, cavities frequency-dependent, in particular pulsating, in particular in the form of a sinusoidal curve, in particular a sinusoidal curve is controllable. The pressure distally and proximally of the clot is advantageously varied over time, so that changes the pressure gradient between the two cavities in its direction of action. This can be done, for example, by alternating supply and removal of fluid volume in a cavity or both cavities, so that the clot is vibrated, whereby the release of the clot is facilitated by the vessel wall. In this case, the change in pressure may be sinusoidal, wherein the time course of the pressure change before or after the clot is coordinated. Other temporal pressure changes are possible, for example in the form of a sinusoidal curve, i. that in both cavities, for example, takes place alternately a discharge of fluid volume.

The control unit may further comprise at least one pressure measuring element which is connected to the suction and / or pressure device such that the pressure which can be generated in the cavities can be measured and / or adjusted. In this way, it can be achieved that the detachment of the thrombus from the vessel wall is detected, since the detachment of the thrombus produces a characteristic pressure change. Furthermore, the pressure-dependent control limits the pressure in the cavities, which risk of injury in the vessel is reduced, as overstretching or collapse of the vessel is avoided.

In a further preferred embodiment of the device according to the invention, a flexible, fluid-tight membrane is provided which, on the one hand, is operatively connected at least to a distal end of the receiving element and on the other hand to the actuating device. Preferably, the flexible membrane with the cover of the receiving element forms a chamber, which is in fluid communication with the suction and / or pressure device, in particular the pressure line such that in use by the pressure in the chamber, the pressure in the proximal cavity is adjustable. In this way, the actuating medium, for example a liquid, is held completely within the device so that the actuating medium, for example, does not interact with the blood outside the cavity. The risk of injury and infection for the patient is thus reduced. At the same time prevents body fluids penetrate into the device and cause an impairment of the function of the device. When the device is equipped with such a flexible membrane, the actuating medium may also comprise a wire connected to the membrane so that the pressure within the proximal cavity can be generated by tensioning or relaxing the membrane. The pressure generation takes place in this variant by simply pulling the wire, which is a well-known and well manageable procedure in medicine, especially in interventional radiology. Furthermore, the wire provides feedback so that the user can develop a sense of the force needed to remove the thrombus and dose it well. The flexible membrane or the chamber formed by the membrane represents an effective partial cavity within the proximal cavity, which takes over the recording and pressure or Unterdruckerzeugungs- function.

The receiving element preferably comprises a proximal end portion, which is substantially cylindrical in shape and connected to the cavity, wherein the longitudinal axial extent of the end portion is adapted such that the end portion is disposed in use at least partially in the feeder. The proximal end portion thus has the function to connect the receiving element for the concretion and the supply device in the expanded state, insofar as the longitudinal axial Extension of the end portion is so dimensioned or adapted that the end portion in use, ie in the expanded state of the receiving element, at least partially disposed in the supply device. This embodiment is, but is not limited to, suitable for combination with the embodiment in which the delivery device itself is designed as a pressure line or as an aspiration catheter. This has the advantage that the cross-sectional diameter of the suction and / or pressure device or the supply device can be made relatively large throughout, so that the efficiency of the pressure / negative pressure generation in the proximal cavity between the fluid-tight cover and the calculus to be removed increases is. The proximal end portion may have an outer diameter corresponding to the inner diameter of the feeder. As a result, pressure losses in the supply system or by the supply system are avoided or at least reduced.

The proximal end portion and the receiving element, in particular the funnel-shaped and the cylindrical portion, are preferably formed in one piece. In this way, the manufacture of the device is simplified.

The cylindrical portion and / or the funnel-shaped portion and / or the proximal portion may comprise a braid. The wire elements can be twisted together, interwoven or intertwined or arranged generally crossing several times. The braid has the advantage that the receiving element has a high flexibility, so that the device can be used in vessel curvatures.

In a further embodiment, at least the cylindrical portion comprises a cross braid, in particular with axially arranged bands. In this case, at least the proximal end portion may include a braid with spiral winding, in particular with axially arranged bands or an asymmetrical braid. The above-mentioned various types of braids may merge into each other such that, for example, the cross braid of the cylindrical portion merges into a spiral winding of the end portion and / or the funnel-shaped portion. The advantage of the axially arranged bands in the spiral wound braid is that the bands can absorb tensile forces and the spiral winding shear forces. The advantage of the cross braid with axially arranged bands is that the axial force would be improved at relatively low elongation. The advantage of the asymmetric braid is that it is highly flexible and can absorb forces and torques in the proximal and distal axial direction.

In the asymmetric grid mesh, the wire elements that overlap in crossing areas have different angles with respect to a straight line extending in the axial direction. Due to the different braiding is achieved that the wire elements that can easily slide on each other in symmetrical mesh braids, block each other, so that a particularly stable grid structure is formed. The asymmetrically braided proximal end portion can thus absorb both axial forces and torques. The grid of the receiving element, which is continued or continued in the region of the proximal end portion, leads through the asymmetric arrangement of the wire elements to a particularly stable structure of the proximal end portion.

In a further preferred embodiment, the proximal end portion and the supply device each have an end stop in such a way that an axial movement of the receiving element in the distal direction can be limited. The proximal end portion may be axially movably disposed in the feeder so that the receptacle is movable relative to the feeder for positioning in a body vessel. By the cooperation of the end stop of the proximal end portion and the end stop of the feed device, the feed movement is limited or limited, so that a release of the receiving element is avoided by the supply device. Rather, a part of the proximal end portion is retained in the feeder. The end stops thus act as retaining means and seal in the stop position, the connection between the end portion and supply device. Thus, the entire lumen of the feeder or microcatheter can be used to generate the pressure or negative pressure in the cavity. Another advantage is that when navigating the supply device or the microcatheter to the concretion, ie the treatment location, no other components, in particular catheter-like elements, are in the feeder, whereby the feeder has a high flexibility and a risk of injury is reduced. The end stop of the proximal end portion may include at least one sleeve connected to the outer periphery of the proximal end portion. The sleeve is a simple means to increase the outer diameter of the proximal end portion locally limited to form the end stop. The sleeve also causes the resulting in the stop position connection between the end portion and the feeder or generally between the receiving element and the feeder is relatively short.

It is also possible to provide more than one sleeve at the proximal end portion, wherein the further proximally arranged sleeves or a further proximally arranged sleeve improves the guidance of the basket or the receiving element.

The sleeve can be connected to the proximal end section in a material-locking, positive-locking, force-locking manner or by a further coaxially arranged sleeve, wherein the proximal end section is clamped between the two sleeves. The substance-coherent connection between the sleeve and the proximal end portion can be done for example by welding, gluing, by spraying the sleeve or by soldering.

The clamping connection, in which the proximal end portion is clamped between a radially outwardly disposed and a radially inwardly and coaxially arranged sleeve, has the advantage of a secure mechanical connection, which is easy to produce.

The end stop of the feeder or of the microcatheter may comprise at least one sleeve which is connected to the inner circumference of the feeder. This version of the end stop is easy to manufacture.

Another possibility is that the end stop comprises a portion of the distal tip of the delivery device, the portion of the distal tip extending radially inwardly and having a smaller inner diameter than a proximal portion of the delivery device. In this embodiment, the end stop can be easily made, for example, by reshaping the feeder in the region of the distal tip. The supply device may comprise an adapter arranged axially movably in the supply device, which adapter is detachably connected to the receiving element, in particular to the proximal end section or to the funnel-shaped section, such that the receiving element is axially movable relative to the feed device. The detachable connection between the adapter and the receiving element or between the adapter and the proximal end section has the advantage that the receiving element can be connected for positioning by the adapter with an actuating element, for example with a guide wire. The receiving element can then be moved in the proximal and distal axial direction through the adapter or through the guide wire connected to the adapter. When the receiving element is positioned, the adapter can be removed from the receiving element, in particular from the proximal end portion and from the supply device, so that it fulfills its dual function, namely the supply of the receiving element and the pressure supply.

In a further preferred embodiment, the receiving element, in particular the proximal end section, is integrally formed with the supply device, in particular with the actuating device or with the suction and / or pressure device. This ensures that the suction and / or pressure device comprises a relatively large lumen, so that the handling of the device is improved and the efficiency of the treatment is increased. It is also possible that the receiving element is controllable by the proximal end portion formed integrally with the supply device, in particular with the actuating device or the suction and / or pressure device. Preferably, the receiving element has a grid structure which extends in the proximal direction into the supply device and thus forms the actuating device, in particular a guide catheter. The grid structure may comprise an asymmetric grid mesh at least in the proximal end section or in the section in which the grid structure forms the actuating device. In this way, the receiving element can be controlled, in particular in the distal or proximal direction to be moved with the continued in the supply grid structure, wherein in the variant with an asymmetric lattice structure in the region of the proximal end portion, an additional stability of the actuator is achieved. A further independent aspect of the invention is to provide a device for removing concrements from body vessels, in particular according to at least one of claims 1 to 18, with a closure element which in use is positionable distally to a calculus and comprises a fluid-tight covering which is adapted to cooperate with at least one concretion to form a distal cavity, wherein the closing element with an actuating device, in particular a suction and / or pressure device, is operatively connected such that in the distal cavity for moving, in particular for releasing the concretion another pressure is adjustable than outside the distal cavity.

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

1 shows a longitudinal section through a device for removing concrements according to an inventive embodiment in use.

2 shows a longitudinal section through a device according to another embodiment of the invention in use.

FIG. 3 shows a longitudinal section through the device according to FIG. 2 in the compressed state; FIG.

4 shows a longitudinal section through a device according to a further embodiment of the invention;

5 shows a longitudinal section through a device according to the invention according to a further preferred embodiment in use.

6 shows a longitudinal section through a pressure line of the device according to FIG.

5; 7 shows a longitudinal section through a pressure generating unit of the device according to FIGS 2 to 4 according to an embodiment of the invention.

8a, 8b each show a time / pressure diagram for the proximal and the distal

Cavity of the device of Figure 5 according to a preferred embodiment.

9a, 9b each show a longitudinal section through a device according to another embodiment of the invention;

10 shows a longitudinal section through a device according to another embodiment of the invention;

11 is a side view of a device according to another embodiment of the invention;

12a shows a side view of a device according to another embodiment of the invention with a variant of the end stops;

12b is a side view of a device according to another embodiment of the invention with a further variant of the end stops;

13a is a side view of a device according to another embodiment of the invention, in which the proximal end stop is releasably connected to an adapter;

13b shows a variant of a sleeve arranged on the basket side, which can be connected to the adapter;

14a is a side view of a device according to another embodiment of the invention in the compressed state. and Fig. 14b is a side view of the device according to Figure 14a in the expanded

Status.

Generally, in the present application, a device for removing conglomerates 51 from blood vessels 50 or other body cavities is disclosed that includes a receiving member 20 having a compressed state of relatively smaller cross-sectional diameter and an expanded state of larger cross-sectional diameter. The receiving element 20 is arranged for insertion and positioning in a blood vessel 50, preferably in a delivery device 10 or a catheter. For receiving the clot 51, the receiving element 20 relative to the catheter, in particular in the distal direction, movable. The receiving element 20 is adapted to take the expanded state automatically. The catheter may include a suction and / or pressure unit, in particular a suction unit or an aspiration catheter, which is connected to the receiving element 20. At the proximal end of the catheter, the device may further comprise an operating unit which cooperates with the catheter for insertion into the blood vessel 50, and / or with the receiving element 20 for transferring the receiving element 20 from the compressed to the expanded state.

1 shows an embodiment of a device according to the invention for removing concrements in use, ie when receiving a concretion or clot 51. The device comprises a receiving element 20 which is arranged distally to the actuating device 11. The receiving element 20 is in the form of a basket or funnel and has a funnel-shaped section 24 which tapers in the proximal direction. The funnel-shaped portion 24 is connected in the distal direction with a cylindrical portion 22, in particular coaxially connected. The cross-sectional diameter of the cylindrical portion 22 of the receiving element 20 substantially corresponds to the diameter of the blood vessel 50, so that the cylindrical portion 22 in the expanded state rests against the vessel wall and supports it. The cylindrical portion 22 forms at the distal end 26 of the receiving element 20 a receiving opening 23 which is at least temporarily closed by the concretion or clot 51 to be removed (see Fig. 1). The distance between the Receiving opening 23 and the funnel-shaped portion 24 and generally the proximal end of the receiving element 20 is dimensioned so that the calculus or clot 51 to be removed in the receiving element 20 is completely or at least largely absorbable.

The receiving element 20 may also have a different shape than the shape shown in Fig. 1. For example, the receiving element 20 may have a shortened cylindrical portion 22 such that the receiving element 20 is funnel-shaped substantially up to the receiving opening 23. The receiving element 20 may also be formed conically, at least in sections. In addition to the rotationally symmetrical shape of the receiving element 20, other cross-sectional profiles can be realized.

The receiving element 20 is further provided at least with a cover 21 or with a coating or a cover, which may be integrally formed with the receiving element 20 or one piece. The cover 21 forms a fluid-tight wall of the receiving element 20. The cover 21 may be produced by sputtering or another coating method as a cantilevered support structure. The cover 21 may be fixedly connected to a grid structure of the receiving element 20. In this case, the cover 21 can be arranged both on an inner surface of the receiving element 20, as well as on an outer surface or an outer circumference of the receiving element 20. The cover 21 may extend over the entire receiving member 20 or cover the receiving element 20 only partially, wherein the cover 21 extends in use at least as far over the vessel cross-section that the blood vessel 50 is substantially completely closed in the proximal direction. For example, the cover 21 may cover only the funnel-shaped portion 24. The cover is made of a fluid-tight material that is sufficiently tight to withstand a pressure differential between the inside and outside of the cover 20.

As shown in FIG. 1, the cover 21 or the receiving element 20 forms a recess curved in the proximal direction or a proximal cavity 30 a. The cover 21 or the cavity 30a itself is through the concretion to be removed closable. This means that the diameter of the cavity 30a or the receiving element 20 corresponds approximately to the diameter of the calculus to be removed. The fluid-tight cover 21 extends so far in the distal direction, in particular to the receiving opening 23, that the proximal cavity 30a is completed in pressure-tight or fluid-tight manner in cooperation with the concretion 51 substantially. By means of the fluid-tight cover 21 on the one hand and the calculus 51 to be removed on the other hand, the proximal cavity 30 a is essentially cut off from the surrounding blood flow in the vessel 50 from all sides. It is all in all important that the fluid-tight cover 21 is formed so that the receiving element 20 fulfills two functions, namely on the one hand, the function of an overpressure and / or vacuum chamber for moving, in particular for releasing the calculus and on the other the function of a receiving space for the concretion 51 dissolved from the vessel.

With regard to the release function of the receiving element 20, this is assigned to the actuating device 11, which is at least in use with the cover 21 and / or the cavity 30a in operative connection. In this case, the actuating device 11 is provided and designed, in cooperation with the cover 21 and / or the cavity 30 a, to move the concretion 51 in the cavity 30 a, in particular to release a different pressure for releasing the calculus to be removed than outside the cavity 30 a, in particular in a region distal to the concretion 51. For this purpose, the actuating device 11 specifically comprises a pressure line 15, in particular a proximal pressure line 15a. The proximal pressure line 15 a is connected at its distal end to the receiving element 20, in particular to the funnel-shaped section 24 of the receiving element 20. In this case, the tubular contour of the proximal pressure line 15a continues partially into the receiving element 20. The pressure line 15 is, as shown in Fig. 1, arranged inside the feeder 10, for example, inside a microcatheter. The pressure line 15, 15a can also be arranged outside the feed device 10 or be formed by the feed device 10 itself. The actuating device 11 further comprises a suction and / or pressure device (not shown), which is fluid-connected to the cavity 30a via the pressure line 15, 15a. By means of the suction and / or pressure device, an actuating medium 14, in particular a liquid, can be introduced into the cavity 30a. be pumped and / or sucked out of the cavity 30 a. By means of the liquid supply, the pressure in the proximal cavity 30a can be increased by means of the actuating device 11 or the suction and / or pressure device if, as in FIG. 1, it is closed at the distal end by the calculus to be removed. By liquid removal or suction of the liquid in the cavity 30 a, the pressure in the cavity 30 a is lowered below the physiological pressure (negative pressure). This means that the physiological pressure acts on the side of the concretion 51 facing away from the cavity 30a, as can be seen from the arrows shown in FIG. As a result, a force acting in the proximal direction, ie in the direction of the receiving element 20, is generated on the concretion 51, which pushes the concretion 51 into the receiving element 20 or the receiving basket. In order to assist the dissolution of the concretion 51 from the vessel wall, an excess and negative pressure can be generated alternately in the cavity 30a.

The receiving element 20 has substantially a stent-like structure and can either be braided from wires or made by laser cutting from a tube. A combination of a wire mesh and a laser cut structure is possible, for example, the funnel-shaped portion 24 may be braided and the cylindrical portion 22 may be laser cut. Preferably, the receiving element 20 is made of a shape memory material, for example nitinol. The cover 21 may comprise, for example, a plastic film or metal foil. Particularly suitable plastics are polyurethane, PTFE or silicone. The production of the metal foil can be done by a sputtering process. The cross-sectional diameter of the receiving element 20 may be between 1 mm and 10 mm, in particular 2 mm and 8 mm, in particular 3 mm and 6 mm. Depending on the application, it is also possible that the receiving element 20 has a cross-sectional diameter between 0.5 mm and 20 mm, in particular 1 mm and 18 mm, in particular 2 mm and 15 mm. The length of the receiving element 20 is also dependent on the particular application, in particular on the treatment site, and may vary between 3 mm and 100 mm, in particular 5 mm and 60 mm, in particular 10 mm and 22 mm.

Overall, in the embodiment according to FIG. 1, the following advantages or effects result: The same pressure gradient prevails over the entire area of the thrombus and pushes the thrombus homogeneously into the basket. The handling is particularly safe and easy for the user as it creates the vacuum through limited volume changes, increasing or decreasing the vacuum arbitrarily and at a controlled rate, depending on the resistance exerted by the thrombus. The movement of the thrombus is felt by the force exerted by the user to generate the negative pressure. He can replace the thrombus with alternating, regular negative pressure and balancing phases from the vessel wall.

For this purpose, a proximal basket spreads out of a catheter (nitinol, superelastic area) and attaches to the vessel wall. The basket is coated by a dense structure so that the proximal side of the thrombus is separated from the flow conditions in the circulation. The basket is connected to the catheter. Defined volume changes in the catheter create a negative pressure that acts on the entire proximal thrombus surface. The negative pressure is understood in relation to the blood pressure that prevails behind the thrombus. When there is a 50 mmHg pressure behind the thrombus, a pressure of 20 mmHg in front of the thrombus is defined as a negative pressure. This effect can be considered as inversion of the pressure gradient from distal to proximal. Distal to the thrombus there may be high, "arterial" pressure when collateral vessels by-pass the occluded vessel portion and bring high pressure blood behind the thrombus, with a pressure gradient of about 80 mmHg behind the thrombus mmHg in a vessel with a diameter of 3 mm, a total force on the thrombus of about 20 gr. could be generated.

However, smaller forces are already sufficient to move the thrombus against the low adhesion to the vessel wall. The degree of volume change can be defined very precisely by the user. It can, for. B. with a syringe, which is connected to the catheter. When a volume is aspirated, a vacuum is created throughout the space between the basket and the thrombus. From a certain negative pressure, the entire thrombus moves towards the basket. The procedure can be carried out very slowly. leads and thus differs significantly from the previous concepts, in which high blood velocity for thrombus removal is required.

According to a further embodiment, a closing element 40 is arranged distally to the receiving element 20 (FIG. 2). The terminating element 40 is substantially drop-shaped or umbrella-like and, like the receiving element 20, can be compressed to a minimum cross-sectional diameter for introduction into the blood vessel 50. The closing element 40 is connected centrally to a wire 14b, or axially displaceably mounted on the wire 14b and fixed by stops. The wire 14b extends axially to the longitudinal axis of the receiving element 20 and the end member 40. The wire 14b is guided in the actuator 11 and movable at least in the axial direction. In use, the wire 14b penetrates the clot 51. The terminating element 40 has, analogously to the receiving element 20, at least partially a distal cover 41 which extends at least so far beyond the terminating element 40 that the blood vessel 50 is substantially completely blocked distal to the clot 51 is closed. The distal cover 41 defines a distal cavity 30b with the vessel wall of the blood vessel 50 and the clot 51. At the proximal end of the closing element 40, a stop 43 is formed, which in use cooperates with the wire 14b of the actuating device 11 such that the clot 51 is manually movable into the receiving element 20. In the region of the stop 43, the closing element 40 may be provided with the distal cover 41. It is also possible that the closing element 40 in the region of the stop 43 has an open structure, for example a filter structure, so that the distal cavity 30 b extends to the distal end of the closing element 40. The end member 40 includes in the distal region a umbrella-like portion 44 provided with the distal cover 41. The umbrella-like portion 44 may also have an open structure, in particular a filter structure, when the stopper 43 is equipped with the distal cover 41.

The combination of the distally arranged screen or closing element 40 with the pressurizable or unterdruckbeaufschlagbaren receiving element 20 as shown in FIG. 2 leads to a further improvement in the safety of the removal system or retriever, as effectively stopped by the final element 40 possibly dissolving thrombus particles so that further downstream vascular occlusion is avoided. In addition, the closing element 40 mechanically strengthens the release force created by the negative pressure in the proximal cavity 30a as the closure member 40 is pulled proximally against the thrombus or concretion. In this respect, this is a combined hydraulic / mechanical system. The pressure line is not explicitly shown in FIG. 2 or may be configured such that the wire 14b is guided in the pressure line 15. Alternatively, the wire 14b may be formed as a hollow wire and constitute an extension of the pressure line 15, which has in the region of the cavity 30a supply or discharge openings for the actuating medium.

The closing element 40 is moved to receive the clot 51 relative to the receiving element 20, in particular in the proximal direction, so that the closing element 40, in particular the stop 43, closes the receiving opening 23 of the receiving element 20 so as to completely close the clot 51 in the receiving element 20 encapsulate. For the final removal of the clot 51 from the blood vessel 50, the actuator 11, the receiving member 20 and the end member 40 is moved in the proximal direction and into a tubular catheter 10a, which has a larger diameter than the feeder 10 and to remove the thrombus or clot 51 serves. In this case, the funnel-shaped portion 24 of the receiving element 20 causes the receiving element 20 is converted into the compressed state. Likewise, the end member 40 is transferred to the compressed state because the receiving opening 23 of the receiving member 20 that tapers upon retraction into the feeder 10 compresses and compresses the end member 40 (FIG. 3).

4 shows a further exemplary embodiment of the device according to the invention, the receiving element 20 and the terminating element 40 having essentially the same structure as already described with reference to FIG. 2. One difference is that the terminating element 40, instead of a wire 14b, is connected centrally to a pressure line 15 which carries an actuation medium 14, in particular a fluid 14a. In principle, the actuation of the device for releasing a concretion or clot 51 can therefore be effected either by a mechanical actuating medium, for example a wire 14b, or by a fluid 14a, ie a liquid or a gas. The pressure line 15 has in the region of the end element 40, in particular between the stop 43 and the umbrella-like section 44, proximal pressure openings 42a, through which the fluid 14a can flow into the distal cavity 30b. In the embodiment according to FIG. 4, the closing element 40 has a distal cover 41 in the area of the umbrella-like section 44, whereas the stop 43 comprises a substantially open structure. The distal cavity 30b thus extends from the umbrella-like portion 44 to the concretion or clot 51. The fluid 14a entering the distal cavity 30b through the distal pressure ports 42b causes a pressure increase in the distal cavity 30b such that between the distal cavity 30b and the proximal cavity 30a creates a pressure gradient. Due to the force acting on the clot 51 due to the pressure gradient, the clot 51 is released and moved into the receiving element 20. It is possible that the receiving element 20 has no cover 21, but is designed as a receiving basket with an open grid structure. The receiving element 20 may additionally assume a filter function, ie that the lattice structure is closely meshed to retain dissolving particles of the clot 51.

As can readily be seen in FIG. 5, the pressure line 15 can also have proximal pressure openings 43a in the area of the proximal cavity 30a. In this case, the receiving element 20 is provided with a proximal cover 21 for forming the proximal cavity 30a. The two cavities 30a, 30b are advantageously coupled via separate pressure lines 15 to a pressure generating unit 13, wherein the proximal cavity 30a a proximal pressure line 15a and the distal cavity 30b is associated with a distal pressure line 15b. The distal pressure line 15b may extend within the proximal pressure line 15a. Alternatively, a 2- or multi-lumen catheter may be used.

In a preferred embodiment, the two cavities 30a, 30b are operatively connected to a common pressure generating unit 16. FIG. 6 shows by way of example such a common pressure generating unit 16, in particular an intracorporeal pump 18, which is arranged centrally in a common pressure line 15 of the two cavities 30a and 30b. The intracorporeal pump 18 is shown in FIG. 6 as Screw conveyor or Archimedes screw formed and connected to a flexible shaft 18a with an extracorporeally arranged drive unit (not shown). The pump is arranged so that liquid from the proximal to the distal cavity 30a, 30b is displaced. The drive unit and the intra-oral pump 18 together form a common pressure generating unit 16, which is preferably connected to a control unit (not shown), so that the conveying direction of the intracorporeal pump 18 is frequency-dependent reversible. In this way, the volume of the actuating medium, the blood trapped in the cavities 30a, 30b or other body fluids is displaced between the cavities 30a, 30b. Alternately, an underpressure or overpressure can be set in the cavities 30a, 30b. In this case, regular pressure changes in the cavities 30a, 30b cause the clot 51 to vibrate and thus detach from the vessel wall of the blood vessel 50.

Alternatively, an extracorporeal pump 17 may also be provided (FIG. 7). The two cavities 30a, 30b are connected to the extracorporeal pump 17 by separate pressure lines 15a, 15b. The common pressure generating unit 16 or the extracorporeal pump 17 comprises two pressure chambers 17c, 17d, which are separated by a pressure membrane 17a. The pressure membrane 17a is flexible and can be vibrated or oscillated. As a result of the oscillation of the flexible pressure membrane 17a, an overpressure or underpressure is alternately generated in the pressure chambers 17c, 17d, which pressure is transmitted through the pressure lines 15a, 15b to the cavities 17a, 17b.

In general, the vibration of the clot 51 can be generated both manually, as well as electronically or mechanically. For example, the actuator 11 may include a syringe or a suitable handle or piston to initiate the oscillation or oscillation of the clot 51. In the case of electronically induced pressure changes, vibrations with frequencies of at least 1 Hz, in particular at least 5 Hz, in particular at least 10 Hz, in particular at least 100 Hz, in particular at least 1000 Hz, in particular at least 20,000 Hz, in particular at least 100,000 Hz, can be generated.

The proximal pressure chamber 17c, ie the pressure chamber 17c associated with the proximal cavity 30, further comprises a port 17b, with which a manual pressure generating unit, for example, a commercially available syringe or a suction device, can be connected. The manual pressure generating unit serves, for example, to suck the clot 51 into a final step into the receiving element 20 as soon as it is released from the vessel wall by the vibrations generated by the pressure membrane 17.

Essentially, the oscillation of the clot 51 is effected in that in at least one of the cavities 30a, 30b alternately an actuating medium 14, specifically a liquid, is supplied or removed. The temporal change of the pressure in front of and / or behind the clot 51 caused thereby can take place, for example, in the form of a sinusoidal oscillation. For example, the pressure generating unit 13 or the common pressure generating unit 16 can be controlled in such a way that liquid is alternately supplied or removed in both cavities 30a, 30b. Such a control is shown in the diagram of FIG. 8a. In this case, the solid line represents the pressure curve in the proximal cavity 30a and the broken line represents the pressure curve in the distal cavity 30b. It is also possible for the oscillation of the clot 51 to take place by alternate liquid removal in the cavities 30a, 30b, as in FIG. 8b shown (sinusoidal curve). To realize the pressure curve according to FIG. 8b, two independently acting pressure generators, for example two pressure diaphragms, are required. The membrane can also be associated with only one of the two cavities 30a, 30b. Furthermore, the volume removal or supply can be carried out separately for each cavity 30a, 30b by means of a syringe, a handle or a piston.

A further variant for generating pressure in the proximal cavity 30a is shown in FIGS. 9a and 9b. In this variant of the device according to the invention the actuating medium 14 is designed as a wire 14b, which is centrally connected to a flexible membrane 25. The flexible membrane 25 is hinged to the distal end 26 of the female member 20 and divides the proximal cavity 30 a into a chamber 31 and a receiving cavity 32. The wire 14b is guided in the actuator 11. In order to move the clot 51 into the receiving member 20, a negative pressure is created in the receiving cavity 32, that is, in the portion of the cavity 30a distal to the diaphragm 25 by moving the wire 14b in the proximal direction relative to the actuator 11. As a result, the flexible membrane 25 is tensioned (FIG. 9b). As with the embodiment according to FIG. 4, in the exemplary embodiment described here, it is not necessarily necessary for the receiving element 20 to be provided with a proximal cover 21.

As can be seen in FIG. 10, the negative pressure in the chamber 31 can also be generated by covering the receiving element 20 in a fluid-tight manner with the proximal cover 21, which defines a closed region with the flexible membrane 25, so that the chamber 31 by suction of an actuating medium 40, in particular a fluid 14a, a negative pressure is generated. This results in a proximal movement of the membrane 25, so that a negative pressure is also caused in the receiving cavity 32, which causes a suction of the clot 51 in the receiving cavity 32.

The receiving element 20 may, as shown in Figure 11, at a proximal end have a proximal end portion 20a. The proximal end portion 20a is preferably disposed within the feeder 10, particularly in use of the device. The length of the proximal end portion 20a is dimensioned such that at least a part of the proximal end portion 20a is arranged in the supply device 10 or in the microcatheter in the case of an expanded basket or receiving element 20. The proximal end portion 20a thus forms an extension of the funnel-shaped portion 24 into the feed device 10 in such a way that - in the expanded state, a stable connection between the feed device 10 and the receiving element 20 is formed. The proximal cover 21 of the receiving element 20 extends into the supply device 10 or at least concludes with the supply device 10 so that the supply device 10 and the receiving element 20 form a substantially fluid-tight system, at least in the expanded state. The proximal cover 21 extends concretely over the cylindrical portion 22, the funnel-shaped portion 24 and the proximal end portion 20a, so that the connection between the feed device 10 and the receiving element 20 is substantially fluid-tight. In this way, the supply device 10 can be used simultaneously as a suction and / or pressure device, in particular as a pressure line 15. The efficiency, in particular the suction power, of the suction and / or pressure device or of the pressure-generating unit 16 is increased, since the inner diameter of the pressure line 15 corresponds to the inner diameter of the feed device 10. In the embodiment according to FIG. 11, the receiving element 20, in particular the funnel-shaped section 22, is formed from a wire mesh. The funnel-shaped section 22 thus comprises a stent-like structure. The grid mesh may alternatively or additionally form the funnel-shaped portion 24 and continue into the proximal end portion 20a. It is possible that the grid mesh, in particular the arrangement of the wire elements or wires, varies along the receiving element 20. The cylindrical portion 22 and the funnel-shaped portion 24 may, for example, have a cross braid. The proximal end portion 20a may also comprise a helical arrangement of the wire elements. The transition between different types of braids may be fluid or continuous. It is also possible to provide the wire mesh of the receiving element 20, in particular the cylindrical portion 22 and the proximal end portion 20a, with axially extending wire elements or ribbons, so that the stability of the device is increased in the axial direction. The axial bands may comprise the same material as the grid of the receiving element 20. It is also possible that the axial bands comprise a different material, in particular a more elastic material. The receiving element 20 may generally be formed in one piece. Suitable materials for the production of the receiving element 20 are shape memory materials, such as nickel titanium alloys, or plastics.

The proximal end portion 20a of the receiving element 20 also has, according to FIG. 11, a proximal end stop 52a. In addition, a distal end stop 52b is provided, which is associated with the supply device 10 and fixedly connected thereto. The end stops 52a, 52b have overlapping diameters and are arranged such that an axial movement of the receiving element 20, in particular the proximal end portion 20a, is limited in the distal direction. This prevents the receiving element 20 from completely escaping from the supply device 10. Between the supply device 10 and the receiving element 20 so an axial relative movement is possible without the two components are separated from each other.

The proximal end stop 52a is disposed substantially on an outer peripheral surface of the proximal end portion 20a. The proximal end stop 52a can be For example, a sleeve 53a, in particular a cylindrical sleeve 53a include. The distal end stop 52b of the feeder 10 forms a mating member to the proximal end stop 52a and is disposed on an inner peripheral surface of the feeder 10 so that the distal end stop 52b is aligned with the proximal end stop 52a in the axial direction. The distal end stop 52b may also include a sleeve 54.

As shown in Fig. 11, the proximal end portion 20a may include another sleeve 53c disposed proximally of the stop sleeve 53a. The further proximal sleeve 53c improves the axial guidance of the receiving element 20 or the basket. The advantage of the exemplary embodiments explained below according to FIGS. 12a, 12b with only one stop sleeve 53a of the proximal end section 20a is the comparatively higher flexibility.

The connection between the end portion 20a and the sleeve 53a can be done for example by welding, gluing, by injection molding or by soldering. Another example of the connection of the sleeves is shown in Fig. 12b. There, it can be seen that the radially outwardly arranged stop sleeve 53a is pressed with a radially inner and coaxially arranged further sleeve 53b. Between the two pressed sleeves 53a, 53b, the tail of the proximal end portion 20a is arranged and clamped between the two sleeves 53a, 53b.

The difference between the embodiment of FIG. 11 and the two embodiments of FIG. 12a and 12b is that the proximal end portion 20a in the embodiments of FIG. 12a, 12b is shorter than in the embodiment of FIG. 11, wherein the longer Execution according to FIG. 11 results from the additional proximal guide sleeve 53c.

The sleeves 53a, 53b, 53c, 54 may be made of plastic, metal, shape memory metal or X-ray visible materials. The diameter of the proximal end portion 20 a is adapted to the inner diameter of the end stop 52 b or the stop sleeve 54 of the feed device 10. The inner diameters of the sleeves 53a, 54, which correspond approximately to each other, are smaller than 1.0, in particular smaller than 0.9, in particular in particular smaller than 0.8, in particular smaller than 0.7, in particular smaller than 0.5, in particular smaller than 0.4, in particular smaller than 0.3 mm. The sleeve wall thickness of the sleeves 53a, 53b, 53c, 54 disclosed above is less than 80 .mu.m, in particular less than 70, in particular less than 60, in particular less than 50, in particular less than 40, in particular less than 30 .mu.m. The wall thicknesses mentioned above have the advantage that the lowest possible pressure drop occurs when the receiving element 20 is actuated. In addition, the lubricity of the basket or the receiving element 20 is improved by the small jump in the caliber.

The edges of the sleeves can be rounded, which is conducive to a low pressure loss and a good sliding of the receiving element 20 and the proximal end portion 20a. Furthermore, the edge rounding of the sleeves is gentle on the coating or cover 21.

As shown in FIGS. 12 a, 12 b, the end stop 52 b of the feed device 10 can be designed as a sleeve, in particular as a catheter sleeve 54. The connection between the sleeve 54 and the supply device 10 can be made cohesively, positively, positively. For example, the sleeve 54 may be bonded to or press-bonded to the catheter tip. It is also possible to form the end stop 52b as part of the catheter tip. The catheter tip 55 can be crimped, glued, pressed, hot-formed or formed by Swedging, for example. It is also possible that the catheter or the supply device 10 is designed in multiple stages. Distally, the feeder may have a smaller diameter than at a proximal location of the feeder 10. The change in diameter may be in multiple sections, with the smallest distal diameter serving as the end stop for the basket sleeve 53a. In the area of the small diameter of the catheter or the supply device is highly flexible. In the area of larger diameters, the feed device is comparatively stiff.

The feeder is characterized by a high flexibility compared to other joining techniques and is well controllable. The two end stops 52a, 52b form sealing means, so that the supply device 10 is connected fluid-tight with the receiving element 20. The seal between the receiving element 20, in particular the proximal cover 21, and the supply device 10 is effected by appropriate interpretation of the tolerances of the end stops 52a, 52b, which may comprise, for example, stop sleeves. Suitable tolerance values are known to the person skilled in the art.

All the features of the end stops disclosed in connection with Figures 12a, 12b and 13a and described in the accompanying text are also independent of the device for the removal of concrements, i. generally disclosed and claimed in the context of a medical device for minimally invasive use. This means that a supply device, in particular a catheter is disclosed and claimed, having the end stops described in the application or the end stop (claim 29).

In addition, all features of the end stops disclosed in connection with Figures 12a, 12b and 13a and described in the accompanying text, also in connection with an arrangement comprising a supply device for medical devices, in particular a catheter with a catheter tip and a medical Device for minimally invasive procedures disclosed and claimed (claim 30).

The embodiment according to FIG. 13 a shows a further improvement of the device in which the receiving basket 20 or the receiving element 20 is movable in both axial directions relative to the feed device 10. Also in this embodiment, the dual function of the feeder 10 is maintained on the one hand for the supply of the receiving element 20 and on the other hand for the pressure supply. For this purpose, the feed device 10 has an adapter 56, which is arranged so as to be axially movable in the feed device 10 and which is releasably connected to the receiving element 20, in particular to the proximal end section 20a. The adapter 56 may also be connected to the funnel-shaped portion 24. In this case, the receiving element 20 is axially movable by the adapter 56 relative to the feed device 10. At the distal end of the adapter 56, a connecting piece 57 is arranged, which is detachably connected to a counterpart 58 of the basket sleeve 53 a. As can be seen in FIG. 13 a, the counterpart 58 of the sleeve 53 a protrudes beyond the proximal end of the proximal end portion 20a and is adapted for releasable connection with the connector 57. This means that the adapter 56 and the receiving element 20 can be temporarily connected for placing or for axially moving the receiving element 20. The adapter 56 is part of a sliding and pulling device for the sleeve 53 a of the end portion 20 a. For this purpose, the adapter 56 may be connected to a guide wire or a push catheter (not shown), for example. It is also possible that the adapter 56 is integrally connected to a catheter or guide wire arranged in the supply device 10 or in general to an actuating element. The adapter 56 is inserted only temporarily into the catheter or into the supply device 10 and used for displacing or placing the receiving element 20. Thereafter, the adapter 56 is removed from the feeder 10.

The connection between the adapter 56 and the sleeve 53a can be done by positive engagement, in particular by thread, barbs or by a click system. As shown in Fig. 13a, the connector 57 has radially outwardly extending lugs 57a, in particular pins, which engage in corresponding recesses in the counterpart 58 of the sleeve 53a. It is possible to provide a single lug 57a, two lugs 57a (as shown in Fig. 13a), three, four or more lugs 57a. The lugs 57a may be arranged symmetrically to each other. The lugs 57a or pins are in each case a rigid elevation which protrudes so far beyond the outer circumference of the connecting piece 57 that a force transmission from the connecting piece 57 via the nose 57a or the lugs 57a to the counterpart 58 of the sleeve 53a is possible , For this purpose, a very small height, for example, of less than 1 mm may be sufficient. Other heights are possible. The lugs 57a provide the prerequisite for a positive connection between the connecting piece 57 and the counterpart 58, wherein the counterpart 58 is adapted accordingly. It is also possible to form the nose 57a and the tabs 57a of an elastic material so that the adapter 56 can be separated from the sheath 53a by overcoming an elastic spring force. The nose 57a and the lugs 57a may be designed to be retractable, in particular counter to a radially outwardly acting spring force retractable. It is also possible to reverse the arrangement of Fig. 13a such that the nose 57a and the lugs 57a are disposed on an inner surface of the counterpart 58 of the sleeve 53a. The connecting piece 57 has corresponding recesses which are adapted such that a detachable form-fitting connection can be produced between the adapter 56 and the sleeve 53a.

It is also possible that a different type of releasable connection is chosen. For example, the adapter 56 may have a connecting piece 57 with an external thread which can be screwed into a corresponding internal thread of the counterpart 58 of the sleeve 53a. The thread may be formed as a helical profile to increase the flexibility of the adapter 56. The adapter 56 may be made of plastic, metal, shape memory metal or X-ray visible materials.

An example of the basket-side sleeve 53a with counterpart 58 is shown in Fig. 13b, which shows a side view of the sleeve 53a. The sleeve 53a comprises at the proximal end the counterpart 58a, which is adapted for releasable connection with the connecting piece 57 of the adapter 56 or of the guide wire. The distal end of the sleeve 53a is formed for connection to the basket 20 and includes a holding portion 59a. The holding portion 59a is also shown in Fig. 13a. In the region of the holding section 59a, the proximal end of the basket 20 is arranged and fixedly connected to an inner surface of the sleeve 53a, for example by gluing, soldering or pressing. Other connection types are possible.

The counterpart 58 is constructed as follows:

The counterpart 58 of the sleeve 53a comprises a substantially L-shaped recess 58a with a longitudinal limb extending in the axial direction of the sleeve 53a, in particular a longitudinal slot, and a transverse limb, in particular a transverse slit, extending substantially in the circumferential direction of the sleeve 53a. It is possible to form the two legs as slots or as recesses arranged in the inner surface of the sleeve 53a, the outer surface of the sleeve being closed. It is also possible, according to FIG. 13b arranged at right angles to the longitudinal leg transverse leg to be arranged at a different angle, for example at an angle <90 °. The number of recesses 58 corresponds to the number of lugs 57a.

The recess 58a acts in the manner of a bayonet closure with the lugs 57a of the connecting piece 57 together. The connection of the two parts is carried out by a combined plug-and-turn movement, wherein a nose 57a is inserted into the longitudinal leg 58a of the recess and secured by rotation in the region of the transverse leg of the recess 58a. To release the connection, the plug-in rotary movement takes place in reverse order.

Other possibilities for realizing the detachable connection between the counterpart 58, the sleeve 53 a and the connecting piece 57 of the adapter 56 also exist. For example, it is possible to provide a thread in the region of the counterpart 58 instead of the L-shaped recess 58a, in which the lugs 57a or a mating thread of the connecting piece 57 engage. Other types of connection, such as latching connections are conceivable.

In the exemplary embodiment according to FIG. 13b, the sleeve 53a is provided with a coil section 59 at least in the area of the distal end. This improves the flexibility of the sleeve 53a. The proximal end with the counterpart 58 is rigid. It is also possible to rigidly form the distal portion of the sleeve 53a. To form the coil section 59, a spiral or helix is cut into the sleeve 53a, which extends over approximately 2/3 of the total length of the sleeve 53a. A shorter or longer helical coil section 59 is possible. In Fig. 13b, the coil section 59 has three turns. A different number of turns, for example, two or more than three turns are possible.

It is also possible to form the entire sleeve 53a as a coil such that the wall of the sleeve over its entire length has a spiral-shaped structure. In the area of the counterpart 58, the spiral-shaped structure forms a thread in which the profile of the connecting piece releasably engages. The arrangement according to FIG. 13b can also be reversed so that the proximal counterpart 58 is designed as a threaded coil. The distal holding Section 59 a may have a closed wall which is fixedly connected to the basket 20.

In addition to or as an alternative to the coil section 59, a plurality of longitudinal grooves may be provided in the area of the distal end, that is to say distally from the coil section 59, into which the proximal end of the basket is pressed, whereby a frictional connection between the sleeve 53 a and the basket 20 is produced. Other types of connection between the holding portion 59a and the basket 20 are possible as described above.

When using the device according to FIGS. 11, 12a, 12b, the receiving element 20, which is initially arranged inside the feed device 10 in the compressed state, is transported into the area of the treatment location. With the aid of an additional catheter, in particular a push catheter, which is temporarily arranged within the feed device 10, the receiving element 20 is moved in the distal direction relative to the feed device 10. The receiving element 20 is thus pushed out of the supply device 10 with the aid of the push catheter. The receiving element 20, in particular the cylindrical portion 22 and the funnel-shaped portion 24, thereby expands or expands. The advancing movement of the receiving element 20 is limited by the two end stops 52a, 52b.

It is possible that the receiving element 20 is first loaded into the feeder 10 in the compressed state, i. before the feeder 10 is guided or navigated to the treatment location. Alternatively, the receiving element 20 can be loaded into the supply device 10 when the supply device 10 is already arranged in the region of the treatment location.

In order to guide the receiving element 20 back into the supply device 10 after expansion in a body vessel, in a device according to FIGS. 11, 12a, 12b, a withdrawal means or catheter-like return tool (not shown) may be provided in the supply device 10 and advanced to the proximal end portion 20a. The return tool can be connected by suitable measures with the receiving element 20. In addition to the adapter In Fig. 13a, other possible types of connection include positive connections, such as a thread or a key bit. The connection can also be made non-positively. For example, the catheter-like retrieval tool may comprise a microballoon which is advanced into the funnel-shaped section 24 of the receiving element 20. The arranged in the funnel-shaped portion 24 microballoon is inflated, so that between the funnel-shaped portion 24 and the microballoon a frictional or frictional connection is formed. The frictional force between the microballoon and the funnel-shaped portion 24 is sufficient to retract the receiving member 20 into the feeder 10.

According to a further embodiment, the device may be formed completely in one piece. In this case, the supply device 10 and the receiving element 20 form a single, tubular or catheter-like component. FIG. 14 a shows such a device in the compressed state of the receiving element 20. The compressed receiving element 20 and the supply device 10 have substantially the same cross-sectional diameter and form a tubular or hose-like body. The feeder 10 forms a rigid portion 60 of the tubular body and is disposed substantially proximally. Disposed distally of the rigid portion 60 is a flexible portion 61 which forms the receiving element 20 in use. The rigid portion 60 differs from the flexible portion 61 in that the rigid portion 60 and the feeder 10 have radial stability, so that the cross-sectional diameter of the rigid portion 60 is substantially invariable. The flexible portion 61 allows an axial length change and at the same time a radial change in diameter. The flexible portion 61 and the receiving element 20 can thus expand.

FIG. 14b shows the device according to FIG. 14a in the expanded state, the flexible section 61 or the receiving element 20 having a larger cross-sectional diameter than in the compressed state (FIG. 14a). The flexible portion 61 and the receiving element 20 can be expanded by a suitable mechanism, for example, within the receiving element 20, a balloon can be arranged, which is inflated to expand the receiving element 20 or filled with a fluid. The balloon may be firmly connected to the receiving element 20 or pansion are arranged within the receiving element 20 and then removed from the receiving element 20. A fixedly arranged balloon may, for example, have a tuning fork-shaped longitudinal section, which is open in the direction of the distal end 26 of the receiving element 20. Further, the balloon may include a plurality of expansion pads, such as airbags, disposed on the inner peripheral surface of the receiving member 20. The rigid section 60 or the supply device 10 may have a plurality of lumens or channels. For the function of inflating or filling the balloon or the pillows and for the function of aspiration of the thrombus, different channels may be provided.

In summary, the invention offers the following advantages:

Controlled thrombus aspiration by limiting the negative pressure area. The negative pressure prevails in a closed area between the proximal basket and the thrombus. A vessel collapse is not possible.

Defined aspiration volume: Only the volume that allows movement of the thrombus into the basket is aspirated. No further blood volume is removed from the vessel.

Limiting the risk of particle separation: The negative pressure is generated when the blood is practically stationary. There are no high blood speeds necessary because no particles are removed by high shear stresses (shear stress) from the thrombus.

Complete and 1-step thrombus aspiration: The invention does not achieve the removal of thrombus particles but the complete movement of the thrombus. LIST OF REFERENCES 0 Feeding device a tubular catheter 1 Actuating device 3 Pressure generating unit Actuating medium a Fluid b Wire Pressure line a Proximal pressure line b Distal pressure line Common pressure generating unit Extracorporeal pump a Pressure diaphragm b Connection c Proximal pressure chamber d Distal pressure chamber Intracorporeal pump a Flexible Weed receiving element a proximal end section proximal cover cylindrical section receiving opening funnel-shaped section membrane distal end a proximal cavity b distal cavity chamber receiving cavity end element distal covera proximal pressure portb distal pressure port

Stop umbrella-like section

blood vessel

Clot a, 52b end stop a, b, c sleeve of the end portion

Sleeve of the feeder

top

adapter

Link s tücka noses

Counterpart a recess

Coil section a holding section rigid section flexible section

Claims

claims

1. A device for removing concrements from body vessels with at least one compressible receiving element (20) for receiving concrements and a feed device (10) for guiding the compressed receiving element (20), characterized in that the receiving element (20) has a fluid-tight cover (20). 21), which forms a closable by the concrement to be removed, in particular proximal cavity (30 a), wherein the receiving element (20) an actuating device (11) is assigned, at least in use with the cover (21) and / or the cavity (30a) is operatively connected such that in the cavity (30a) for moving, in particular for releasing, the calculus to be removed, a different pressure is adjustable than outside the cavity (30a).

2. Device according to claim 1, characterized in that the actuating device (11) comprises a suction and / or pressure device, which is fluid-connected or fluid-connectable to the cavity (30a).

3. Device according to claim 2, characterized in that the suction and / or pressure device comprises a pressure-generating unit (13) which is fluid-connected or fluid-connected to the cavity (30a) by a pressure line (15), wherein the pressure line (15) is arranged in or outside the feed device (10) or formed by the feed device (10) itself.

4. The device according to at least one of claims 1 to 3, characterized gekennz eichnet that the actuating device (11) comprises an actuating medium (14), in particular a liquid, at least partially pumpable into the cavity (30 a) and / or out of the cavity (30a) is sucked.

5. Device according to at least one of claims 1 to 4, characterized in that the receiving element (20) is in the form of a basket and has a distal, essentially Lent cylindrical portion (22), which comprises a receiving opening (23) for receiving a concretion.

6. Device according to at least one of claims 1 to 5, characterized geke nnz eichnet that the receiving element (20) has a proximal, substantially funnel-shaped portion (24) with the actuating device (11), in particular the suction and / or Printing device is connected.

7. The device according to at least one of claims 1 to 6, characterized marked eichn et, that the cover (21) with the actuating device (11), in particular the pressure line (15), fluid-tight manner.

8. The device according to at least one of claims 1 to 7, characterized in that the receiving element (20) is associated with a closing element (40), in particular a screen, which in use can be positioned distally to the concrement.

9. The device according to claim 8, characterized in that the terminating element (40) has a fluid-tight cover (41) which is adapted to form a distal cavity (30b) in cooperation with at least the concretion to be removed.

10. Device according to claim 8 or 9, characterized in that the terminating element (40) is fluid-connected to the pressure line (15), which is assigned to the receiving element (20), or to another, separate pressure line such that in the distal one Cavity (30b) for moving, in particular for releasing, the concretion of a different pressure is adjustable than outside the distal cavity (30b).

11. The device according to at least one of claims 8 to 10, characterized geke nnz eichnet that the closing element (40) and the receiving element (20) with the activation of direction (11), in particular of the suction and / or pressure device, are fluid-connected such that between the distal cavity (30b) and the proximal cavity (30a) for moving, in particular for releasing, arranged between the cavities (30a, 30b) Concrements different, in particular changeable, relative pressures are adjustable.

12. The device according to at least one of claims 8 to 11, characterized gekennz eichnet that the closure element (40) and the receiving element (20) with a common pressure generating unit (16) are connected.

13. The device according to claim 12, characterized in that the common pressure generating unit (16) is arranged extracorporeally and comprises at least one oscillatable pressure membrane (17a), which at least in use fluidly connected to the closing element (40) and / or the receiving element (20) or is fluid-connectable.

14. The device according to claim 12, characterized in that the common pressure generating unit (16) comprises a feed pump, in particular a trachop oral feed pump (18), which is arranged inside the pressure line (15) such that the feed pump is at least in use with the closing element (40) and / or the receiving element (20) fluidly connected or fluidly connected.

15. The device according to at least one of claims 3 to 14, characterized in that the pressure generating unit (13), in particular the common pressure generating unit (16), is assigned a control unit which is adapted such that a pressure change in at least one, in particular both, cavities (30a, 30b) frequency-dependent, in particular pulsating, in particular in the form of a sinusoid, in particular a sinusoidal curve, is controllable.

16. The apparatus according to claim 15, characterized eichne t that the control unit comprises at least one pressure measuring element which is connected to the suction and / or pressure device such that the pressure which can be generated in the cavities (30a, 30b) is measurable and / or adjustable.

17. The device according to at least one of claims 1 to 16, characterized in that the receiving element (20) comprises a flexible, fluid-tight membrane (25), on the one hand at least with a distal end (26) of the receiving element (20) and on the other the actuating device (11) is operatively connected.

18. The apparatus according to claim 17, characterized in that the flexible membrane (25) with the cover (21) of the receiving element (20) forms a chamber (31) with the suction and / or pressure device, in particular the pressure line (15), is fluidly coupled such that in use by the pressure in the chamber (31) the pressure in the proximal cavity (30a) is adjustable.

19. A device for removing concrements from body vessels, in particular according to at least one of claims 1 to 18, with a closure element (40) which is positionable in use distal to a concretion and in a fluid-tight cover (41), which is to form a distal Cavity (30b) is adapted to cooperate with at least one concretion, wherein the closure element (40) with an actuating device (H), in particular a suction and / or pressure device, is operatively connected such that in the distal cavity (30b) for moving, in particular for releasing the concretion, a different pressure is adjustable than outside the distal cavity (30b).

Device according to at least one of claims 1 to 19, characterized in that the receiving element (20) comprises a proximal end portion (20a) which is substantially cylindrical in shape and connected to the cavity (30a), the longitudinal axial extent the end portion (20a) is adapted such that the end portion (20a) in use at least partially in the supply means (10) is arranged.

21. Device according to claim 20, characterized in that the cylindrical section (22) and / or the funnel-shaped section (24) and / or the proximal end section (20a) comprise a braid.

22. Device according to claim 20 or 21, characterized in that at least the cylindrical portion (22) is a cross braid, in particular with axially arranged bands and at least the proximal end portion (20a) is a spiral wound coil, in particular with axially arranged bands or an asymmetrical one Braid include.

23. The device according to at least one of claims 20 to 22, characterized in that the proximal end portion (20a) and the feed device (10) each have an end stop (52a, 52b) such that an axial movement of the receiving element (20) in Distal direction is limited.

Device according to claim 23, characterized in that the end stop (52a) of the proximal end portion (20a) comprises at least one sleeve (53a) connected to the outer periphery of the proximal end portion (20a).

25. The device according to claim 24, characterized in that the sleeve (53a) is connected to the proximal end section (20a) in a material-locking, positive-locking, force-locking manner or by a further coaxially arranged sleeve (53b), the proximal end section (20a) being between the two sleeves (53a, 53b) is clamped.

26. The device according to at least one of claims 23 to 25, characterized in that the end stop (52b) of the supply device (10) is connected to at least one sleeve (54) which is connected to the inner circumference of the supply device (10) or a part of distal tip (55) of the feeder (10) extending radially inwardly is extended and has a smaller inner diameter than a proximal part of the feed device (10).

27. Device according to one of claims 1 to 26, characterized in that the supply device (10) has an axially movable in the supply device (10) arranged adapter (56) with the receiving element (20), in particular with the proximal end portion (20a ) or the funnel-shaped portion (24), releasably connected is such that the receiving element (20) relative to the feed device (10) is axially movable.

28. Device according to one of claims 1 to 27, characterized in that the receiving element (20), in particular the proximal end portion (20a), with the supply means (10), in particular with the actuating device (11) or with the suction and / or Printing device, is formed in one piece.

29. A medical device delivery device, in particular catheter with a catheter tip, which has an end stop (52b), wherein the end stop (52b) at least one sleeve (54) connected to the inner circumference of the supply device (10), or a part of distal tip (55) of the delivery means (10) which extends radially inwardly and has a smaller inner diameter than a proximal part of the delivery means (10).

30. Arrangement comprising a supply device. for medical devices, in particular, a catheter with a catheter tip and a medical device for minimally invasive procedures, wherein the supply means comprises a first end stop (52b), the at least one sleeve (54), which is connected to the inner circumference of the feed device (10), or a portion of the distal tip (55) of the delivery device (10) extending radially inwardly and having a smaller inner diameter than a proximal portion of the delivery device (10), and wherein the medical device comprises a second end stop (52a) with the first first end stop (52b) cooperates such that an axial movement of the medical device can be limited in the distal direction.