WO2010139479A2

WO2010139479A2 - Medical catheter, medical functional element and assembly comprising such a catheter, and such a functional element

Info

Publication number: WO2010139479A2
Application number: PCT/EP2010/003380
Authority: WO
Inventors: Giorgio Cattaneo
Original assignee: Acandis Gmbh & Co. Kg
Priority date: 2009-06-03
Filing date: 2010-06-04
Publication date: 2010-12-09
Also published as: DE112010001841A5; DE102009023661A1; WO2010139479A3

Abstract

The invention relates to a medical catheter having a line (10) and a tip (20) which is connected to a distal section (11) of the line (10) and which has a smaller external diameter than the line (10), wherein the section (11) comprises a constant first internal diameter. The invention is characterized in that, in the rest state, the tip (20) has a second internal diameter which is smaller along the entire length of the tip (20) than the first internal diameter of the section (11). The invention further relates to a medical functional element and to an assembly comprising such a catheter and such a functional element.

Description

Medical catheter, medical functional element and arrangement comprising such a catheter and such a functional element

description

The invention relates to a medical functional element and a medical catheter according to the preamble of claim 5. Such a catheter is known for example from US 5,599,319 A. Furthermore, the invention relates to an arrangement comprising a catheter and a functional element

The known medical catheter comprises a catheter lead, which is integrally connected to a catheter tip, wherein the catheter tip has a smaller outer diameter than the catheter lead. The inner diameter or the lumen of the catheter is constant over the entire length. This means that the wall thickness of the catheter line is greater than the wall thickness of the catheter tip. In this way it should be achieved that the catheter line has a sufficiently high stability and the catheter tip, however, comprises increased flexibility in order to be controllable in curved blood vessels.

A similar catheter is known from US 5,976,120 A. In this case, the wall thickness of the catheter tip is also reduced in order to provide increased flexibility.

In general, different requirements are placed on the tip of a catheter. In order to allow the accessibility of the catheter to small blood vessels or the patency of the catheter in highly curved vessels, a relatively high flexibility is required. At the same time, the catheter should have a relatively high axial stability under axial pressure loading, ie when pushing the catheter. The axial stability should also be ensured when the catheter is pulled or when an implant, such as a stent, is guided through the catheter to the destination. An additional requirement results from the fact that the radial expansion force acts in particular of stents on the inner wall of the catheter. Therefore, the catheter should have a corresponding radial stability, so that the implant or the stent does not cut into the catheter material in the radial direction. In the known medical catheters, the contradiction between flexibility and axial or radial stability is to be resolved by reducing the wall thickness in the catheter tip. The internal diameter is kept constant over the entire catheter. Due to the reduced wall thickness and the relatively large inner diameter, however, there is the risk that the catheter tip kinks or collapses when it is introduced into a blood vessel. As a result, the feeding of the known catheter is made difficult in a blood vessel, as increased by the buckling of the catheter tip of Reibungswiders tand between the catheter and a guide wire. This disadvantage is particularly evident when guiding the catheter through narrow vessel bends. Furthermore, due to the constant inner diameter, which is preferably adapted to the outer diameter of a crimped or compressed stent, the known catheters have relatively large cross-sectional dimensions, so that small blood vessels, in particular in the cerebral region or in the region of the eyes, can not be reached.

Catheter areas with small wall thickness with the same inner diameter also have a low radial load capacity. Due to the self-expandable implants or devices in the crimped state in the catheter radially outward directed force may therefore come to deformation of the thin-walled area. In doing so, the lattice structure of the implant or device may be incorporated into the material of the catheter, e.g. cut into the plastic and prevent further movement of the implant.

The disadvantages occurring with known catheters are explained by way of example with reference to FIGS. 13-15. FIGS. 13-15 show a blood vessel 200, in particular a branching of cerebral arteries. In this case, an inner secondary vessel 201 and an outer secondary vessel 202 branch off from a main vessel 203. The branch angle between the main vessel 203 and the inner side vessel 201 is relatively small, thereby making it difficult to supply a catheter 300 from the main vessel 203 into the inner side vessel 201.

As shown in FIG. 13, according to a known method of supplying a catheter 300, first, a guide wire 100 is guided through the main vessel 203 into the inner sub-vessel 201. In a next step, the catheter 300 is advanced over the guidewire 100 into the main vessel 203. In a catheter 300 that is designed to have a relatively high axial stability, there is a risk that, as shown in FIG. 14, the catheter tip 301 of the catheter 300 of FIG Kjcümmung the Führungsdr ahht 100 can not follow, whereby upon further advancement of the catheter 300, the guide wire 100 from the target vessel, such as the inner side vessel 201, is pushed out. The guide wire 100 is pulled in the direction of the outer secondary vessel 202.

Another problem arises when - as shown in Fig. 15 - a catheter 300 is used, which is designed for a relatively high flexibility, with an impairment of the axial and radial stability is taken into account. There is a risk that the catheter 300 or the catheter tip 301 curls, whereby the catheter tip 301 compresses in the axial direction, i. is shortened. The catheter tip 301 thus partially collapses on the guidewire 100. This increases the frictional resistance between the guidewire 100 and the catheter 300, which makes further advancement of the catheter 300 more difficult. The change in length of the catheter tip 301 also complicates the exact positioning of a stent, since the position of the distal opening 302 of the catheter 300 changes as a result of the change in length of the catheter tip 301.

The invention therefore has the object of providing a medical catheter having a relatively high flexibility with high kink resistance. The invention is further based on the object of specifying a functional element that is adapted for use with the catheter, as well as an arrangement comprising a catheter and a functional element.

According to the invention, this object is achieved with regard to the functional element and the arrangement by the subject matters of claims 1 and 4. With regard to the catheter, the object is achieved by the subject matter of patent claim 5, alternatively by the subject matter of claim 18 and further alternatively by the subject matter of claim 19.

The invention is based on the idea of providing a medical catheter with a lead and a tip connected to a distal portion of the lead, which has a smaller outer diameter than the lead, wherein the distal portion of the lead has a constant first inner diameter. The tip has a second inner diameter at rest, which is smaller than the first inner diameter along the entire length of the tip. It has been shown that increased kink resistance is generally achieved by a smaller inner diameter. Furthermore, increased flexibility is provided by the smaller cross-sectional dimension of the tip so that the tip of the invention along a guidewire can follow very small vessel bends. Thus, the smaller, second inner diameter of the tip prevents the guidewire following the curvature of the blood vessel from being forced out of the curved state when the catheter of the invention is passed over the guidewire. Thus, he allows for the medical catheter according to the invention a treatment in vessel regions which have a relatively small vessel cross-section or are difficult to reach due to narrow vessel curvatures. Due to the constant first inner diameter of the first portion of the conduit, a sufficiently high stability of the catheter is effected, so that an implant, in particular a stent, can be guided safely to the treatment site. In the compressed state, the implant preferably has a cross-sectional diameter which substantially corresponds to the first inner diameter of the first section of the conduit.

Preferably, the tip of the medical catheter is flexible. In this case, the flexible tip can be adapted such that the second inner diameter can be enlarged in use, in particular can be adjusted to the first inner diameter or expanded beyond the first inner diameter. This allows a catheter guided by the implant, which preferably has a cross-sectional diameter corresponding to the first inner diameter of the first portion of the conduit, passed through the tip and thus from the catheter can be released. The tip which can be widened beyond the first inner diameter thereby enables a partial expansion of the implant in the catheter tip, so that the diameter of the implant approaches the diameter of the vessel to be treated. This allows a gentle implantation that reduces the risk of injury to a vessel wall.

In a preferred embodiment of the medical catheter, the tip has an axially extending taper which is connected to the distal portion and forms a substantially continuous transition from the first inner diameter to the second inner diameter. That is, a continuous transition between the different first and second inner diameters is formed. As a result, when an implant is being delivered, the tip is widened uniformly through the implant without the implant penetrating the catheter wall of the tip cuts. In addition, the risk of breakage is reduced in the continuous transition.

The tip may include a support structure that stabilizes the tip in the axial direction. An axial stabilization is expedient, since in this way a change in length of the tip is avoided. This will ensure that the position of the catheter tip or distal end of the catheter is maintained in use. Thus, an exact positioning of an implant or stent is possible.

Preferably, the support structure comprises a braided or spirally wound wire and / or at least one band extending parallel to a central longitudinal axis of the tip. By a braided wire structure or generally grid structure, a widening of the tip is achieved from the second inner diameter to at least the first inner diameter particularly advantageous. In this case, the grid mesh allows by appropriate design of the grid angle that the maximum expansion of the tip is adjustable or limited. The band extending in the axial direction causes stabilization of the tip in the axial direction, so that a change in length of the tip can be limited or avoided. The positioning of an implant is thus improved.

In a further preferred embodiment of the medical catheter according to the invention, the conduit comprises further sections, each having a constant third inner diameter, wherein the further sections are each connected by joints which are annular and at rest have a fourth inner diameter, which is smaller than the third Inside diameter is. The joints, which form portions of the smaller inner diameter pipe, allow for relatively high flexibility of the pipe while avoiding collapse of the pipe. In particular, it is achieved by the joints that the line can follow narrower radii of curvature of vessels, as a result of which smaller vessels, in particular blood vessels in the cerebral region, can be reached with the catheter. At the same time a sufficiently high stability in the axial direction is effected by the sections with the constant third inner diameter.

Preferably, the third inner diameter substantially corresponds to the first inner diameter and / or the fourth inner diameter substantially to the second inner diameter. That means the first section and the other sections have substantially the same, constant inner diameter and the tip and the joints comprise substantially the same, smaller inner diameter. The preparation of the catheter is thus simplified.

The joints may further include a camber extending radially toward the central longitudinal axis of the flexible conduit. The curvature allows the joints or the fourth inner diameter in the region of the joints to be widened by advancing an implant in the lumen of the catheter. The actuation or deformation of the joints is thus preferably carried out by the implant movable in the lumen of the catheter. In this case, the curvature can be adapted so that a cutting of the implant is avoided in the joint.

In a further embodiment of the medical catheter, the joints are deformable in use such that the fourth inner diameter is enlarged, in particular approximately equal to the third inner diameter. As a result, the medical catheter is suitable for feeding an implant or a stent into a body vessel, wherein the implant or the stent has a cross-sectional diameter which corresponds to the third inner diameter or the inner diameter of the sections. When passing the implant through the flexible conduit, the deformable joints allow expansion of the fourth inner diameter so that the implant can pass. By the fourth inner diameter is variable in the region of the joints, so a relatively high flexibility of the catheter is provided, the flexibility is achieved by reducing the inner diameter in the joints. At the same time, the catheter thus has a relatively high axial stability.

It is particularly advantageous if the joints in the deformed state have a bias that causes a return of the joints in the resting state. The bias or restoring force of the joints makes it possible that the joints, which has already passed the implant, are returned to the original, smaller inner diameter. This means that the catheter as a whole remains relatively flexible, even if a segment of the catheter undergoes stiffening due to the enlargement of the inner diameter in the joints, which at this time are widened by an implant.

Advantageously, the further sections are connected by a hinge to the distal section, wherein the distal section and the further sections have substantially the same length. The length of the sections can be, for example be adapted to the length of a stent to be implanted, so that the expansion of the fourth inner diameter takes place alternately in the region of the joints. This means that when the stent or general implant is advanced through the conduit, in each case a joint is widened and a joint arranged proximally to this joint is compressed or returned to the resting state. In this way it is prevented that the total length of the catheter or the conduit during the delivery of an implant varies significantly. Thus, an exact positioning of the implant is possible.

Furthermore, the joints may comprise an annular grid structure, in particular a braided wire structure. By appropriate design of the braiding angle, the braided structure or the mesh braid makes it possible to limit the maximum expansion of the joints to a defined larger inner diameter. Furthermore, the braided structure allows a determination of the geometry of the joints in the expanded state. For example, the grid structure or the grid mesh may be formed such that the joints in the deformed state, in particular in the maximally expanded state, have a directed to the central longitudinal axis of the line curvature. This prevents the joints from overstretching or overstretching when the flexible conduit is guided into tight vessel bends. Furthermore, the mesh provides a simple way to adjust the bias of the joints or the spring force of the joints.

In a further preferred embodiment of the medical catheter, the joints and the tip have a wall thickness which substantially corresponds to the wall thickness of the conduit, in particular of the distal portion and the further portions. In particular, the wall thickness is substantially constant along the entire catheter. As a result, on the one hand good flexibility of the catheter over the entire length of the catheter is achieved, and on the other hand the catheter can be designed overall with a relatively small cross-sectional diameter.

The wall thickness of the smaller second inner diameter regions may be smaller than the wall thickness of the larger second inner diameter regions. This is possible because the smaller inner diameter regions are more radially stable so that the wall thickness can be reduced. This leads to increased flexibility and deformability, for example when an implant is moved axially and the joint or the tip widen radially outward. Alternatively, in the context of the invention, without being limited to a specific embodiment of the catheter tip, the line comprise a plurality of sections with a constant first inner diameter, wherein the sections are each connected by annular joints having a second inner diameter at rest, the smaller than the first inner diameter is (claim 18). As a result, a good flexibility is achieved with high kink stability of the catheter.

Accordingly, the objects claimed independently of one another are based on the common idea of forming a catheter in sections with different inner diameters, a first larger diameter substantially corresponding to the outer diameter of a functional element, in particular stents, movably arranged in the catheter. The second diameter is smaller than the first diameter, the first diameter forming the lumen of the catheter into which the second smaller diameter portions protrude. The lumen forms the interior of the catheter or the catheter line through which a functional element, for example a stent for implantation or for release, is conveyed in a vessel. The first diameter therefore essentially corresponds to the diameter of the functional element to be conveyed. The substantially shorter sections with the second diameter projecting into the lumen lead to an acceptable resistance during transport of the functional element, since the second diameter is adapted such that the functional element widens the regions with the second diameter as it passes through an axial movement in the catheter. It is also possible to move the stent by means of a pusher which allows the stent to taper as it passes the second diameter regions. The combination of longer sections with a larger first diameter with shorter sections with a smaller second diameter has the advantage that the catheter or the catheter line has a good flexibility in axial and radial stability. For example, the shorter, smaller diameter sections may form the joints between the longer portions or the tip of the catheter. Both the joints and the tip have a second inner diameter that is smaller than the first diameter of the longer compared to the joints or to the tip sections. Compared to the tip, a single section having the first larger inner diameter may be approximately the same length. In sum, however, the portions with the first major inner diameter of the conduit are longer than the second smaller inner diameter tip. The wall thickness in the region of the different diameters of the catheter is essentially the same. Thus, the outer contour of the catheter or the catheter line corresponds to the inner contour.

Furthermore, in the context of the invention, a medical catheter is claimed, which is characterized by a combination of an outer diameter range with a wall thickness range (claim 19). Surprisingly, it has been found that this combination leads to good flexibility, without the kink resistance of the catheter line being significantly impaired.

The invention will be explained in more detail below by means of embodiments with reference to the accompanying schematic drawings. Show in it

1 shows a longitudinal section through a medical invention

Catheter at rest according to a preferred embodiment;

FIG. 2 shows the catheter according to FIG. 1 in its intended use within a blood vessel; FIG.

Figures 3-7 the catheter of FIG. 1 during the release of a

implant;

Fig. 8 is a longitudinal section through a medical invention

Catheter according to another preferred embodiment;

9 is a longitudinal section through a medical invention

Catheter according to another preferred embodiment;

FIG. 10 shows a partial longitudinal section through the catheter according to FIG. 9 in a curved state; FIG.

Figures 11 and 12 illustrate the catheter of Figure 9 in passing an implant through the lumen of the catheter lead; and

Figures 13-15 is a cross-sectional view of a blood vessel during insertion of a

Catheter according to the prior art. Referring to Fig. 1, a catheter according to an embodiment of the present invention includes a conduit 10 which defines in a distal region of the catheter a first or distal portion 11 which is directly or directly connected to a tip 20 of the catheter. The conduit 10 may be flexible, rigid or rigid. The rigid or rigid conduit 10 is intended for an endoscopic puncture device. A combination of a rigid line from section with a distal flexible line section is also possible. The conduit 10, together with the tip 20, forms a lumen 30, or channel, which, in use, forms an artificial body orifice to a body vessel. The lumen 30 preferably has a circular or oval cross-section. A circular cross section is preferred so that the catheter as a whole forms a rotationally symmetrical body. The line 10, in particular the first or distal section 11, has a constant outer diameter and a constant inner diameter. The wall thickness of the line 10 is adapted such that the line 10 on the one hand is flexible and on the other hand provides sufficient axial and radial stability. It is also possible, the line 10 with a non-flexible wall, for example. Form of metal.

The tip 20 has a smaller outer diameter and a smaller inner diameter than the first portion 11 of the conduit 10. Thus, the tip 20 has a smaller cross-section than the first section 11. This increases the flexibility of the tip 20 so that the tip 20 can follow tighter radii of curvature in body vessels. Between the first portion 11 of the conduit 10 and the tip 20, a taper 23 is formed which is associated with the tip 20. The taper 23 forms a smooth transition from the first portion 11 of relatively larger cross-sectional diameter to a distal opening 21 of the tip 20 having a relatively smaller cross-sectional diameter.

The first portion 11 of the conduit 10 is directly connected to the tip 20, wherein the tip 20 is preferably adapted such that the second inner diameter widens to place the implant in the vessel. The second inner diameter of the tip 20 is at rest over the entire length of the tip 20 smaller than the first inner diameter. The second inner diameter can be substantially constant. It is also possible for the second inner diameter to taper in the distal direction along the entire length of the tip 20. The advantageous mode of operation of the catheter according to the invention is shown by way of example in FIG. Therein is shown a section through a blood vessel 35 having a vessel branch. The illustration according to FIG. 2 shows, by way of example, the branching of the main vessel 35c into the inner secondary vessel 35a and the outer secondary vessel 35b. For supplying the catheter via the main vessel 35c into the inner secondary vessel 35a, a flexible guide wire 25 is first guided through the main vessel 35c into the inner secondary vessel 35a. In a further step, the catheter is advanced over the guide wire 25. As shown in Fig. 2, while the tip 20 of the catheter has a smaller inner diameter than the conduit 10 and the first portion 11 of the conduit 10. Preferably, the inner diameter of the tip 20 is adapted such that between the guide wire 25 and the catheter 20 is a relatively small game. In this way it is achieved that the sliding on the guide wire 25 catheter tip 20 has a high flexibility and can follow the narrow radius of curvature of the guide wire 25. The tip 20 also causes the further advancement of the catheter, the line 10 and the first portion 11 is guided in the predetermined by the guide wire 25 curvature. This means that the first section 11 or the line 10 follows the curvature of the tip 20. In this way, small blood vessels 35 can also be reached via narrow branches.

The tip 20 may also assume a maximum inner diameter that is smaller than the inner diameter of the distal portion 11. The restoring force of the tip 20 and the radial force of the stent can be adjusted by design parameters so that the expansion takes place to a desired diameter.

The line 10, in particular the first section 11, preferably has an inner diameter that substantially corresponds to the outer diameter of a compressed implant, in particular a compressed stent 26. In this way, the catheter is suitable for the delivery of implants or stents 26 into a blood vessel, wherein the accessibility of relatively small blood vessels 35 is ensured by the approximation of the inner diameter of the line 10 to the outer diameter of the stent 26. The tip 20 also has a radial flexibility relative to its central longitudinal axis. In this respect, the inner diameter of the tip 20 is variable. In particular, the tip 20 is adapted so that the inner diameter of the tip 20 is increased.

Due to the radial flexibility of the tip 20, it is possible for a stent 26 adapted in the compressed state to the inner diameter of the conduit 10 to be made of the distal one Opening 21 of the catheter tip 20 can be discharged into a blood vessel 35. The expansion of the tip 20, as shown in Fig. 3, achieved by the advancing movement of the stent itself. In particular, due to the continuous or continuous transition formed by the taper 23 between the larger inner diameter of the first portion 11 and the idle inner diameter of the tip 20, an expansion of the tip 20 is effected during advancement of the stent 26 into the tip 20. In this case, the tip 20 is adapted such that the maximum expansion defined is limited. For example, the tip 20 may be constructed such that a widening of the tip 20 to at most the inner diameter of the first portion 11 and the conduit 10, as shown in Fig. 4. It is also possible that the tip 20 widens beyond the inner diameter of the conduit 10. This means that the tip 20 in use has at least the same inner diameter as the conduit 10. The tip 20 thus has a radial restoring force which compresses the tip 20 to the smaller inner diameter of the resting state. The radial restoring force of the tip 20 can be matched with the radial force of the stent 26 to be implanted, ie, the force causing the expansion of the stent 26. In particular, the radial restoring force of the tip 20 may be designed such that the frictional resistance between the stent 26 and the radial tip 20 occupies a minimum.

As shown in FIG. 4, the radial expansion of the tip 20 may extend over the entire length of the tip 20. Preferably, after discharge of the stent 26 from the distal opening 21, the tip 20 resumes its original resting state.

FIGS. 5-7 show the functioning of the catheter during the release of a stent 26 in the region of a plaque 38 or thrombus to be treated in a blood vessel 35. Stent 26 has a crimped or compressed cross-sectional diameter which is slightly smaller than the cross-sectional diameter of the stent Blood vessel 35 is at the treatment or equivalent. The advancing movement of the stent 26 is effected by an actuating element 27 which is frictionally connected to the stent 26 (friction element). It is also possible to use a pusher with an end stop. The actuator 27 is further fixedly connected to the guide wire 25, so that by a movement of the guide wire 25, the stent 26 in the catheter, in particular the line 10 and the tip 20, slides. By an axial displacement of the stent 26 from the first portion 11 into the tip 20, a widening of the tip 20 is effected as shown in FIG. As can also be seen in FIG. 5, the relatively small cross-sectional diameter tip 20 allows delivery of the catheter into treatment areas in which the original cross-sectional diameter of the blood vessel 35 is narrowed by a plaque 38. As the flexible tip 20 expands upon release of the stent 26, the plaque 38 is forced into the vessel wall of the blood vessel 35, thereby achieving a first expansion of the stenotic blood vessel diameter. The flexible tip 20 therefore offers an advantage, in particular in the implantation of stents 26, which have an expanded cross-sectional diameter which substantially corresponds to the compressed cross-sectional diameter, as shown in FIG. An alternative variant in which the stent 26 has an expanded cross-sectional diameter which is greater than the compressed cross-sectional diameter is shown in FIG.

FIG. 8 shows a further exemplary embodiment of the catheter according to the invention. In this case, the catheter has, in addition to the first, distal section 11 of the line 10, further sections, in particular a second section 12 and a third section 13. The sections 11, 12, 13 are connected to each other by joints 14. In this case, the joints 14 form segments of the line 10, which have a smaller inner diameter than the sections 11, 12, 13. In particular, the joints 14 are annular or form on the outer circumference of the line 10 annular grooves on the inner circumference of the line Form 10 corresponding ribs. This means that the wall thickness of the joints 14 essentially corresponds to the wall thickness of the sections 11, 12, 13. The joints 14 essentially form a concertina-like or fold-algartige connection between the individual sections 11, 12, 13th

The number of connected by the joints 14 sections 11, 12, 13 is not limited.

The sections may each have different first inner diameters, which are each constant per section. It is also possible to vary the inner diameter per section, whereby the joint function should not be affected. Expediently, the first inner diameter of the sections 11, 12, 13 corresponds to the inner diameter of the overall line 10 of the catheter. Thus, at least along the region to be introduced into the body, the line 10 has a substantially constant lumen, which is interrupted in sections by the joints with the respective smaller second inner diameters. Advantageously, the joint arrangement is provided in the distal line region, which requires a particularly good flexibility in axial and radial stability. The proximal conduction area of the Catheter may be formed in a conventional manner. The distal and proximal lead regions can have the same inner diameter.

The regions with the narrowed diameter, ie the regions in which the joints 14 and / or the tip 20 are formed, are adapted such that the smaller second inner diameter is smaller than the outer diameter of a functional element displaceably arranged in the catheter or in the catheter line, especially stents, is. This leads to the desired interaction between the areas with the smaller second inner diameter and the functional element or stent. Furthermore, it follows that a proximal region of the catheter tube has substantially the same inner diameter as the first inner diameter of the sections 11, 12, 13. Thus, the guiding function of the catheter inner wall for the functional element is fulfilled all the way to the tip along the entire catheter line.

The advantage of the joints is that the flexibility in a relatively long range of the catheter line can be increased, specifically in the entire area in which the elongated portions 11, 12, 13 and the joints 14 are arranged alternately, without being too long range is formed with a constant small inner diameter. The longitudinal extension of the joints 14 is much shorter than the longitudinal extension of the elongate intermediate sections 11, 12, 13. Therefore, a relatively small force is required for axially displacing the stent 26, since only a portion of the stent surface is exposed to increased friction in the hinge area. As the area, e.g. the length of the stent is 26 or more, consists of several shorter areas with smaller inner diameter (joints 14), the flexibility is given, the stent 26 can be advanced with less friction, since only some portions of the stent 26 in contact with narrower areas the line 10 (joints 14) are.

Thus, the joint assembly is not only claimed in connection with the tapered on the inner circumference tip, but also protected regardless of the design of the tip. For example, the inner diameter of the tip may be larger if a broader, and non-deformable marker is attached to the tip. It is also conceivable that the stent or device should be retracted into the tip, which requires a large tip width and radial stability in the distal region. In this case, the catheter is wider and more stable at the tip and the radial taper of the inner circumference is in the form of joints proximal thereto. All features relating to the joints are disclosed and claimed both in the context of the tapered tip 20 and independently of the tapered tip 20.

For the sake of clarity, the joints 14 and the support 20 are shown highlighted in the following figures 9-12. This is to clarify that the joints 14 and the tip 20 mainly cause the flexibility of the catheter. The straight sections 12, 13, 14 provide the axial stability of the catheter. It is possible, but not provided, that the joints 14 and the tip 20 have a different material from the sections 11, 12, 13. The joints 14 may also have the same material as the sections 11, 12, 13. In particular, the joints 14 and the sections 11, 12, 13 and the tip 20 may be integrally formed.

The joints 14 on the one hand and the elongated sections 11, 12, 13 on the other hand may consist of a plastic or of different plastics and / or a reinforcement by braiding or coil. It may be that in the joint 14 the reinforcement is omitted or the reinforcement in the joint area has different properties, e.g. has a different braiding or winding angle than the reinforcement in the straight sections 11, 12, 13.

Preferably, the hinges 14 have a bulge 14a that extends radially in the direction of the central longitudinal axis of the catheter. The curvature 14a is well recognizable in the resting state of the catheter, as shown for example in FIG. The curvature of the curvature 14a preferably corresponds in the state of rest to the shape of a parabola or a semicircle. This means that the curvature 14a is formed in the state of rest concave or semi-oval or partially elliptical to the central longitudinal axis of the line 10 out. It is further contemplated that in a widening of the inner diameter of the joints 14 up to a defined maximum, the curvature 14a is still present, wherein the radius of curvature varies. When the catheter is guided through a vessel curvature, the radius of curvature of the curvature 14a along the outer edge of the vessel curvature is thereby increased. The radius of curvature of the curvature 14a in the region of the inner wall of the vessel curvature remains the same or becomes smaller. This behavior of the joints 14 is exemplified in Fig. 10, wherein the portions 11, 12, 13 of the conduit 10 are guided over the curved guide wire 25.

The operation of the joints 14 during the advancement of a stent 26 through the lumen 30 of the catheter is shown in FIGS. 11 and 12. The axial causes Displacement of the stent 26 a radially acting on the joints 14 force component, which leads to a widening of the inner diameter of the joints 14. The interaction between the joints 14 and the stent 26 essentially corresponds to the coordinated behavior between the tip 20 and the stent 26. The joints 14 preferably widen to an inner diameter which substantially corresponds to the inner diameter of the sections 11, 12, 13 or ., the line 10 corresponds. It is preferred that, as shown in Fig. 12, the curvature 14a is maintained even in the maximally expanded state of the joints 14, wherein the radius of curvature is increased relative to the resting state. In this way, an expansion of the flexible joints is avoided.

The length of the sections 11, 12, 13 may be matched to the length of the stent 26 such that upon axial displacement of the stent 26 only one hinge 14 is widened in each case. In particular, the length of the sections 11, 12, 13 is dimensioned such that upon expansion of a joint 14 by the stent 26 at the same time a proximally arranged joint 14 is returned by the own restoring force in the resting state. This ensures that the expansion of the joints 14 a total of a change in length of the catheter is avoided. This means that the change in length is compensated by the expansion of a joint 14 by the simultaneous return of another joint 14. During delivery of the stent 26, there is thus an earthworm-like or wave-like movement of the catheter, which is compensated for by corresponding length adaptation between the stent 26 and sections 11, 12, 13, so that the position of the catheter tip or the distal opening 21 is kept substantially constant becomes.

The catheter has the following advantages, in particular because of the flexible joints 14 compared to the prior art:

The joints 14 have a smaller inner and outer diameter than the sections 11, 12, 13, whereby the flexibility of the catheter is increased; By the catheters in the axial direction stabilizing sections 11, 12, 13 a collapse or untidy crimping of the catheter is avoided.

In particular, by the predetermined movement of the joints 14 and the predetermined geometry of the curvature 14 a is made possible that the catheter on the one hand along a guidewire 25 is feasible, in particular without an increase in the friction between the guide wire 25 and catheter by a wave-like curl Catheter wall. Furthermore, the joints 14 allow the delivery of a stent 26 into a blood vessel 35.

The tip 20 preferably has a braid or braiding, which widens when advancing the stent 26 into the tip 20 up to a defined inner diameter. Alternatively, the tip may be a coil, i. a spiral wound wire. The maximum expansion of the tip 20 can be determined by the angle of the mesh braid (braiding angle) or the angle of the spiral turn of the coil. The maximum possible expansion can also be determined by material properties.

Preferably, the joints 14 also have a mesh or a spirally wound wire. Alternatively or additionally, the tip 20 may comprise a plastic, for example PTFE, or be coated with a plastic. Advantageously, the tip 20 comprises one, two, three, four or more axial bands, which fix the tip 20 in the axial direction, so that a change in length of the tip 20 is avoided. The axial bands may comprise a radiopaque material.

Overall, the braid can determine the adjustment of the (maximum) extent of the tip 20 or the joints 14 when pushing the stent 26, or the joints 14 at curvature of the area with the joints 14. The mesh or coil changes the braiding or coil angle during expansion. Increasing the angle increases the deformation force, especially when the mesh is embedded in a plastic. Upon reaching a maximum angle selectable by the person skilled in the art, further expansion is no longer possible. In one embodiment, the braid is provided continuously between the sections and the hinges 14 and / or the tip 20. The angle may be greater in the sections 11, 12, 13 than in the region of the joints 14 and / or tip 20, in particular of the taper 23. The shallow angle in the region of the joints 14, and / or the tip 20, in particular the taper 23 expands when passing through the stent 26 and becomes larger, e.g. as large as the angle in the region of the sections 11, 12, 13, when the diameter is reached.

In general, it is sufficient for the expandability of the joints 14 and the tip 20, that the wall of the catheter is elastic. For example, it is possible that the wall of the catheter is made of plastic. In this case, a plastic can be used, which can be stretched elastically to a maximum degree, so that the expansion of the Tip 20 or a joint 14 is set to a maximum value or maximum diameter by the professional to be made by the choice of material.

Thus, the tip 20 and the joints 14 may be formed either entirely of plastic or a combination of plastic with a coil or a braid. In both cases, the corresponding areas of the catheter may be designed so that the expansion does not lead to the maximum value of the elongation or the elastic deformability, but up to a diameter of the tip 20 and / or the joints 14, in which a balance between the radial force of the functional element, in particular of the stent and the restoring force of the tip 20 and / or the joints 14 sets.

In the case of an arrangement comprising the catheter and a functional element, in particular a stent, which is moved in the uncrimped state through the catheter or the catheter line, the expansion of the tip 20 and / or the joints 14 takes place up to the outer diameter of the functional element. Since the functional element exerts no additional radial force, the expansion of the tip 20 and / or the joints 14 is limited to the outer diameter of the functional element. In this case, it is not necessary to set a maximum extensibility of the tip 20 and / or the joints 14.

In a further embodiment relating to the arrangement comprising the catheter and the functional element, the tip 20 and / or the joints 14 may be rigid in the radial direction or stiffer than the wall of the functional element, in particular of the stent, at least in the radial direction. In this case, the functional element widens when passing through or passing through the tip 20 or the joints 14 these very little or not at all. Rather, the diameter of the functional element adapts to the smallest diameter of the tip 20 and / or the joints 14.

The inner diameter in the resting state of the joints 14 and / or the tip 20 is preferably at most 30%, in particular at most 35%, in particular at most 40%, in particular at most 45%, at most 50%, in particular at most 55%, in particular at most 60%, in particular at most 65%, in particular at most 70%, in particular at most 75%, in particular at most 80%, in particular at most 85%, in particular at most 90%, of the inner diameter of the sections 11, 12, 13 or the line 10. Preferably, the inner diameter of the tip is 20 at rest at most 0.5 mm, in particular at most 0.45 mm, in particular at most 0.4 mm, in particular at most 0.35 mm, in particular at most 0.3 mm, in particular at most 0.25 mm, in particular at most 0.2 mm, in particular at most 0.15 mm, in particular at most 0.1 mm.

For the treatment of small blood vessels with a diameter between 500 microns and 1 mm, it has proved to be advantageous if the tip 20 at rest has an outer diameter of at most 1 mm, in particular at most 0.8 mm, in particular at most 0.6 mm , in particular not more than 0.4 mm, in particular not more than 0.3 mm, in particular not more than 0.2 mm, in particular not more than 0.1 mm. In this case, the catheter, in particular the tip 20, preferably has a wall thickness which is at most 100 μm, in particular at most 75 μm, in particular at most 50 μm, in particular at most 40 μm, in particular at most 30 μm, in particular at most 20 μm.

For the treatment of vessels with a cross-sectional diameter of at most 500 microns, an outer diameter of the tip 20 is preferably at most 0.6 mm, in particular at most 0.4 mm, in particular at most 0.2 mm, in particular at most 0.15 mm, in particular at most 0.12 mm, in particular at most 0.1 mm, in particular at most 0.08 mm, in particular at most 0.06 mm. In this case, the wall thickness of the catheter, in particular the tip 20, is preferably at most 30 μm, in particular at most 20 μm, in particular at most 10 μm, in particular at most 5 μm.

The tip 20 preferably has a length that is at most 50 mm, in particular at most 30 mm, in particular at most 15 mm, in particular at most 10 mm, in particular at most 5 mm, in particular at most 3 mm.

All values mentioned in connection with the tip 20 apply to all embodiments disclosed in this application, in particular also for the joints 14.

It has proven to be advantageous to combine the above-described embodiments for the catheter, in particular the embodiment in which the outer diameter of the tip 20 is less than 0.2 mm or less with a wall thickness of less than 30 microns, with a medical functional element , which is a hollow body-shaped lattice structure made of grid elements, which has a wall with a Wall thickness forms, has. The grid structure has a diameter, in particular an inner or outer diameter, of 200 .mu.m or less and a wall thickness of 10% or less of the diameter, in particular of 8% or less, in particular of 5% or less, in particular of 3% or less of the diameter. The inner or outer diameter may also be at most 100 .mu.m, in particular at most 80 .mu.m, in particular at most 50 .mu.m, wherein the wall thickness has the aforementioned proportions of the diameter. The wall thickness or the thickness of the grid elements, in particular the wire thickness, is preferably at most 15 μm, in particular at most 12 μm, in particular at most 10 μm, in particular at most 8 μm, in particular at most 7 μm, in particular at most 6 μm, in particular at most 5 μm. This has the advantage that a functional element with a flat wall can be supplied to the body through a flexible and sufficiently axially and radially stable catheter. Specifically, the risk of in-stent restenosis and thrombosis is reduced by the flat-walled functional element, since the grid elements of the functional element protrude only slightly into the vessel volume. This affects the blood flow conditions in the vessel as little as possible. In particular, the formation of dust areas behind the grid elements or webs is avoided, which lead to a change in the physiological conditions on the vessel wall.

For larger blood vessels, functional elements or stents with a diameter, in particular an expanded diameter, between 200 .mu.m and 1 mm, in particular between 250 .mu.m and 1 mm, in particular between 300 .mu.m and 1 mm, having a wall thickness which is at most 5% of the diameter, in particular not more than 4%, in particular not more than 3%, in particular not more than 2%, in particular not more than 1% of the diameter. The upper limit of the diameter, in particular of the expanded diameter, can be 900 μm, in particular 800 μm, in particular 700 μm, in particular 600 μm, in particular 500 μm, in particular 400 μm, in particular 300 μm. For example, in the case of a stent with a diameter of 1 mm, the wall may have a wall thickness of 50 μm or less, in particular of 10 μm or less. For a stent having a diameter of 500 μm, the wall thickness may be 25 μm or less, in particular 5 μm or less.

For stents having a diameter, in particular an expanded diameter, of 200 μm or less, in particular of 180 μm or less, in particular of 160 μm or less, in particular of 140 μm or less, in particular of 120 μm or less, in particular of 100 μm or less, in particular of 80 μm or less, in particular of 60 μm or less, the wall thickness can be 10% or less of the diameter, in particular 9% or less, in particular 8% or less, in particular 7% or less, in particular 6 % or less, in particular 5% or less, in particular 4% or less, in particular 3% or less, in particular 2% of the diameter. The lower limit of the diameter, in particular of the expanded diameter, can be 40 μm, in particular 60 μm, in particular 80 μm, in particular 100 μm. For example, in the case of a stent having a diameter of 200 μm, the wall may have a thickness of 20 μm or less, in particular of 6 μm or less, in particular of 4 μm or less. In the case of a stent with a diameter of 100 μm, the wall thickness may be 10 μm or less, in particular 3 μm or less, in particular 2 μm or less.

A further improvement of the properties of the functional element, in particular of the stent is achieved by adjusting the ratio of the height to the width of the grid elements, in particular the webs. Thereby, a weakening of the radial force can be compensated, which possibly occurs due to the flat-walled design of the functional element, in particular of the stent. By increasing the web width in relation to the wall thickness, the radial force of the stent can be improved. The web width contributes more to the improvement of the radial force, as the wall thickness and that approximately in the ratio 3: 1. This can be compensated by a small increase in the web width, the reduction in wall thickness.

For grid elements or webs with a width B and a height H, it has proven to be expedient if the ratio B / H is at least 0.5, in particular at least 1, at least 2, at least 3, at least 5, at least 7, at least 10 , at least 15. In known stents, the ratio B / H is usually less than 0.5.

The functional element described above is disclosed and claimed both in connection with the catheters or delivery systems disclosed in this application and independently thereof.

In connection with the combination of the functional element with a medical catheter, there is disclosed an assembly comprising a medical catheter having a conduit and a medical function element disposed in the crimped state with a first diameter in the conduit. The functional element is by discharge from the line from the crimped state in one expanded resting state with a second, larger diameter convertible. The ratio of the first diameter of the functional element in the crimped state to the second diameter in the expanded state of rest is 0.3 or more, in particular 0.5 or more, in particular 0.7 or more, in particular 0.9 or more. This means that the function dement, especially the stent is only slightly crimped. This has the advantage that thin-walled functional elements can be supplied to the catheter without the functional elements deforming or collapsing inwards. As a result, functional elements, in particular stents with very fine grid structures, can be implanted without the risk of damage. For the arrangement, a catheter is particularly suitable, which has a tapered tip 20, as shown for example in Figures 3 to 7. In this case, the outer diameter of the functional element is matched to the inner diameter of the tip 20 so that when passing through the tip 20 it is widened and transferred from the second smaller inner diameter to the first larger inner diameter, which corresponds to the first inner diameter of the catheter line 10. By virtue of this arrangement, it is also possible to release stents which have relatively wide webs, since the grid cells of the stent need not be deformed or only slightly deformed by the small crimping or by the supply in the uncrimped state, which accommodates a broad web geometry.

A functional element, in particular a stent with a ratio of the first diameter in the crimped state to the second diameter in the expanded state, in particular rest state of 0.3 or more, in particular 0.5 or more, in particular 0.7 or more, in particular 0.9 or more is revealed both together and independently of the catheter.

The thin-walled functional elements, implants and the like described above can be produced by sputtering and photolithographic etching. In particular, by the recently developed manufacturing techniques for producing self-supporting, in particular sputtered functional elements can be very thin wall thicknesses achieved. This applies to both cylindrical and planar functional elements, which are converted into cylindrical shape in use. It is also possible to produce the wall thicknesses described above by interweaving correspondingly thin wires with a diameter of 10 μm or less, in particular of 5 μm or less. As materials for the thin-film technology as well as wire materials are nickel-titanium alloys, chromium-cobalt alloys, such as Phynox, Elgiloy, stainless steels (eg 316 LVM), platinum and / or Platinum alloys, in particular platinum-iridium alloys, magnesium and / or magnesium alloys and tungsten or tungsten alloys, in particular titanium-tungsten alloys or tungsten-rhenium alloys in question. In general, materials such as magnesium, iron or tungsten and their alloys can be used, which have bioadsorbable properties. It is also possible to use plastic filaments such as Dynema to form the grating structure. The described thin-walled functional elements can also be made of bioresorbable plastics.

The catheters and functional elements described above, in particular stents, are particularly suitable for the treatment of a retinal arterial occlusion (eye stroke) as well as for the treatment of narrowing of the veins in the eye. In retinal artieria occlusion, occlusion of the central retinal artery (Arteria Centralis Retinae) of the eye occurs. This is followed by an oxygen deficiency of the retina. The cause of the occlusion may be an engorged blood clot (embolism), most commonly from a cervical artery or resulting from cardiac arrhythmia caused by a thrombus. After 60 to 90 minutes, permanent retinal damage already occurs. The examination revealed almost complete loss of vision, a lack of pupil reflex, and a white-grayish discoloration of the non-perfused sections of the retina in the fundus. Treatment attempts with massage of the eyeball for the embolus solution, anticoagulation and lowering of the intraocular pressure are known, but only to a limited extent.

In addition to the arterial occlusions described above, venous occlusions can also be created and treated with the above-described catheters and functional elements or arrangements thereof. Venous occlusions are often caused by arteries in the eye hardened by atherosclerosis, pushing on a crossing vein. If a blood clot forms at the appropriate place in the vein, it will be relocated.

The arterioles in the eye area have a diameter between 5 .mu.m and 100 .mu.m and can not be reached with conventional catheters. The catheters, functional elements and the combination of these catheters and functional elements described in the context of the application provide the prerequisite for miniaturization sufficient for the treatment of arterial occlusions or arteriolar occlusions in the eye area. Therefore, the use of a medical functional element or a medical catheter according to at least one of the above-described Embodiments disclosed and claimed, which is intended for the treatment of arterioles or veins in the eye area. Furthermore, a corresponding treatment method is disclosed and claimed.

Alternatively, it is also possible to use the catheter as an aspiration catheter for small vessels, in particular with a diameter of less than 1 mm.

The functional element, in particular the stent, may have medications stored in its structure. The medicaments can, for example, be incorporated in a manner known per se in a coating of the lattice structure (drug eluting stent). Such functional elements can be used for the treatment of vessels, in particular of arterioles or venules in the eye area or for the treatment of vessels in other areas.

The functional element, in particular the stent, may have a covering, for example, of PU, silicone or Teflon.

LIST OF REFERENCE NUMBERS

10 line

11 first section

12 second section

13 third section

14 joint

14a vaulting

20 tip

21 distal opening

23 rejuvenation

25 guidewire

26 stents

27 B essication element

30 lumens

35 blood vessel

35a inner side vessel

35b outer side vessel

35c main vessel

100 guidewire 200 blood vessel

201 inner side vessel

202 outer side vessel

203 Main vessel

300 catheters

301 Catheter tip

302 distal opening

Claims

claims

1. Medical functional element comprising a hollow body-shaped

Grid structure of grid elements, which forms a wall with a wall thickness, characterized in that the grid structure has a diameter of 200 microns or less and a wall thickness of 10% or less of the diameter, in particular 9% or less, in particular 8% or less, in particular 7 % or less, in particular 6% or less, in particular 5% or less, in particular 4% or less, in particular 3% or less, in particular 2% or less, of the diameter or the lattice structure has a diameter between 200 μm and 1 mm and a wall thickness of at most 5% of the diameter, in particular at most 4%, in particular at most 3%, in particular at most 2%, in particular at most 1% of the diameter.

2. Functional element according to claim 2, characterized in that the grid structure in the crimped state has a first diameter and from the crimped state in an expanded state with a second diameter can be transferred, wherein the ratio of the first diameter in the crimped state to the second diameter in the expanded state of rest 0.3 or more, in particular 0.5 or more, in particular 0.7 or more, in particular 0.9 or more.

3. Functional element according to claim 1 or 2, characterized in that the grid elements have a width B and a height H, wherein the ratio B / H at least 0.5, in particular at least 1, at least 2, at least 3, at least 5, at least 7, at least 10, at least 15.

4. Arrangement comprising a medical catheter with a line (10) and a medical functional element with a hollow body he-shaped grid structure of grid elements, in particular according to claim 1 or 2, arranged in the conduit (10) and located in the crimped state with a first diameter is, wherein the functional element by discharge from the conduit (10) from the crimped state in an expanded state of rest with a second Diameter is transferable, characterized in that the ratio of the first diameter in the crimped state to the second diameter in the expanded state of rest is 0.3 or more, in particular 0.5 or more, in particular 0.7 or more, in particular 0.9 or more.

A medical catheter having a conduit (10) and a tip (20) connected to a distal portion (11) of the conduit (10) and having a smaller outer diameter than the conduit (10), the portion (11) being a constant first inner diameter, characterized in that the tip (20) in the resting state has a second inner diameter which is smaller than the first inner diameter of the portion (11) along the entire length of the tip (20).

6. A medical catheter according to claim 5, characterized in that the tip (20) is flexible such that the second inner diameter is enlarged in use, in particular to the first inner diameter equalizable or beyond the first inner diameter also expandable.

7. A medical catheter according to claim 5 or 6, characterized in that the tip (20) has an axially extending taper (23) which is connected to the distal portion (11) and a substantially continuous transition from the first inner diameter forms the second inner diameter.

8. Medical catheter according to at least one of claims 5 to 7, characterized in that the tip (20) comprises a support structure which stabilizes the tip (20) in the axial direction.

9. A medical catheter according to claim 8, characterized in that the support structure comprises a braided or spirally wound wire and / or comprises at least one band, which is parallel to a central longitudinal axis the tip (20) extends.

10. Medical catheter according to at least one of claims 5 to 9, characterized in that the conduit (10) comprises further portions (12, 13) having a constant third inner diameter, said portions (11, 12, 13) respectively ring-shaped joints (12) are connected, which have a fourth inner diameter at rest, which is smaller than the third inner diameter.

11. Medical catheter according to claim 10, characterized in that the third inner diameter substantially corresponds to the first inner diameter and / or the fourth inner diameter substantially to the second inner diameter.

12. A medical catheter according to claim 10 or 11, characterized in that the joints (14) have a curvature (14 a) which extends radially in the direction of the central longitudinal axis of the flexible conduit (10).

13. A medical catheter according to at least one of claims 10 to 12, characterized in that the joints (14) are deformable in use such that the fourth inner diameter is enlarged, in particular approximately equal to the third inner diameter.

14. Medical catheter according to at least one of claims 10 to 13, characterized in that the joints (14) in the deformed state ver have a bias which causes a return of the joints (14) in the resting state.

15. A medical catheter according to at least one of claims 10 to 14, characterized in that the further sections (12, 13) are connected by a hinge (14) to the distal section (11), wherein the distal section (11) and the further sections (12, 13) have substantially the same length.

16. Medical catheter according to at least one of claims 10 to 15, characterized in that the joints (14) comprise an annular lattice structure, in particular a braided wire structure.

17. Medical catheter according to at least one of claims 12 to 16, characterized in that the joints (14) and the tip (20) have a wall thickness substantially equal to the wall thickness of the conduit (10), in particular of the distal portion (11). and the further sections (12, 13) corresponds.

18. A medical catheter having a conduit (10) which comprises a plurality of sections (11, 12, 13) with a constant first inner diameter, characterized in that the sections (11, 12, 13) each connected by annular joints (12) are, which have a second inner diameter at rest, which is smaller than the first inner diameter.

19. A medical catheter having a conduit (10) and a tip (20) connected to a distal portion (11) of the conduit (10), characterized in that the tip (20) has an outer diameter of 0.2 mm or less, in particular of 0.15 mm or less, in particular 0.12 mm or less, in particular 0.10 mm or less, in particular 0.08 mm or less, in particular 0.06 mm or less and a wall thickness of 30 μm or less, in particular 20 μm or less , in particular of 10 μm or less, in particular of 5 μm or less.

20. Arrangement according to claim 4 with a catheter according to one of claims 5 to 19.

21. Use of a medical functional element, in particular according to one of claims 1 to 3, an arrangement according to claim 4 or 20 and a medical catheter according to one of claims 5 to 19 for the treatment of arterioles and / or venules in the eye area.