MEDICAL SYSTEM FOR TREATING STENOSIS IN INTRACRANIAL VESSELS

Abstract

The disclosure relates to a medical system for treating stenosis in intracranial blood vessels including a compressible and self-expandable implant for covering the stenosis, said implant having a lattice structure, at least some sections of which are provided with a cover made of an electrospun fabric, wherein the fabric has irregularly sized pores, and a balloon catheter for dilating the stenosis and/or introducing the implant into the blood vessel.

Claims

1-16. (canceled)

17. A medical system for the treatment of stenosis in intracranial blood vessels comprising: a compressible and self-expandable implant for covering the stenosis, the implant having a mesh structure at least a section of which is provided with a covering produced from an electrospun fabric having irregularly sized pores; and a balloon catheter for dilating the stenosis and for delivering the implant into the blood vessel.

18. The medical system as claimed in claim 17, wherein the covering comprises at least 10 pores with a size of between one of 5 μm.sup.2 and 15 μm.sup.2 or at least 15 μm.sup.2 over an area of 100000 μm.sup.2.

19. The medical system as claimed in claim 17, wherein the balloon catheter has at least two channels and a balloon, wherein an inflation channel of the at least two channels is in fluid communication with the balloon, and a delivery channel of the at least two channels extends through the balloon, and wherein the delivery channel has a proximal inlet opening and a distal outlet opening for deploying the implant.

20. The medical system as claimed in claim 19, wherein in a compressed state, the implant is one of configured to move through the delivery channel or disposed in the delivery channel.

21. The medical system as claimed in claim 19, wherein the balloon catheter comprises three X-ray markers, wherein a first X-ray marker is disposed in a region of the distal outlet opening of the delivery channel, a second X-ray marker is disposed in a region of a distal balloon end, and a third X-ray marker is disposed in a region of a proximal balloon end.

22. The medical system as claimed in claim 19, wherein the delivery channel has a friction-reducing inner coating for a translational movement of the implant in the delivery channel.

23. The medical system as claimed in claim 18, wherein each of the at least 10 pores of the covering has an inscribed diameter of at least 4 μm.

24. The medical system as claimed in claim 17, wherein the covering comprises at least 15 pores with a size of at least 30 μm.sup.2over an area of 100000 μm.sup.2.

25. The medical system as claimed in claim 24, wherein the pores are at most 750 μm.sup.2 in size.

26. The medical system as claimed in claim 17, wherein the covering is securely connected to the mesh structure.

27. The medical system as claimed in claim 17, wherein the mesh structure is sheathed with a bonding agent at least one of in parts or in sections, and wherein the bonding agent forms a mechanical interlock between the covering and the mesh structure.

28. The medical system as claimed in claim 17, wherein the covering is produced from a plastic material.

29. The medical system as claimed in claim 17, wherein the covering is formed from irregular filaments disposed in a network-like manner and having a filament thickness of between 0.1 μm and 3 μm.

30. The medical system as claimed in claim 17, wherein the covering has a biocompatible coating.

31. The medical system as claimed in claim 30, wherein the coating contains one of fibrin or heparin.

32. The medical system as claimed in claim 31, wherein the heparin is one of covalently bonded to the fibrin or incorporated into the fibrin.

33. A medical system for the treatment of stenosis in intracranial blood vessels comprising: a compressible and self-expandable implant for covering the stenosis, the implant having a mesh structure at least a section of which is provided with a covering produced from an electrospun fabric having irregularly sized pores; and a balloon catheter for dilating the stenosis and for delivering the implant into the blood vessel, wherein the covering has at least 10 pores with a size of between one of 5 μm.sup.2 and 15 μm.sup.2 or at least 15 μm.sup.2 over an area of 100000 μm.sup.2.

34. The medical system as claimed in claim 33, wherein the balloon catheter has at least two channels and a balloon, wherein an inflation channel of the at least two channels is in fluid communication with the balloon, and a delivery channel of the at least two channels extends through the balloon, and wherein the delivery channel has a proximal inlet opening and a distal outlet opening for deploying the implant.

35. The medical system as claimed in claim 34, wherein the balloon catheter comprises three X-ray markers, wherein a first X-ray marker is disposed in a region of the distal outlet opening of the delivery channel, a second X-ray marker is disposed in a region of a distal balloon end, and a third X-ray marker is disposed in a region of a proximal balloon end.

36. A medical system for the treatment of stenosis in intracranial blood vessels comprising: a compressible and self-expandable implant for covering the stenosis, the implant having a mesh structure at least a section of which is provided with a covering produced from an electrospun fabric having irregularly sized pores; and a balloon catheter for dilating the stenosis and for delivering the implant into the blood vessel, wherein the balloon catheter has at least an inflation channel, a delivery channel, and a balloon, wherein the inflation channel is in fluid communication with the balloon, and the delivery channel extends through the balloon, and wherein the delivery channel has a proximal inlet opening and a distal outlet opening for deploying the implant.

Description

[0056] The invention will now be explained in more detail with the aid of exemplary embodiments and with reference to the accompanying drawings, in which:

[0057] FIG. 1: shows a side view of a stent of a medical system in accordance with the invention according to a preferred exemplary embodiment;

[0058] FIG. 2: shows a microscope image of a covering of the implant of a medical system in accordance with the invention according to a preferred exemplary embodiment;

[0059] FIG. 3: shows a microscope image of a covering of the implant of a medical system in accordance with the invention according to a further exemplary embodiment;

[0060] FIG. 4: shows a perspective view of a mesh structure of a stent of a medical system in accordance with the invention according to a further preferred exemplary embodiment;

[0061] FIG. 5: shows a scanning electron microscope image of a covering of the implant of a medical system in accordance with the invention according to a further preferred exemplary embodiment, at 500× magnification;

[0062] FIG. 6: shows a scanning electron microscope image of the covering of FIG. 5, under 3500× magnification;

[0063] FIG. 7: shows a longitudinal section through the balloon catheter of a medical system in accordance with the invention according to a preferred exemplary embodiment;

[0064] FIG. 8: shows a cross section through the balloon catheter of a medical system in accordance with the invention according to a further preferred exemplary embodiment with coaxially disposed channels;

[0065] FIG. 9: shows a cross section through the balloon catheter of a medical system in accordance with the invention according to a further preferred exemplary embodiment with adjacent disposed channels;

[0066] FIG. 10: shows a longitudinal section through the balloon catheter in accordance with FIG. 8; and

[0067] FIG. 11: shows a longitudinal section through the balloon catheter in accordance with FIG. 8, wherein in addition, X-ray markers are provided.

[0068] The accompanying figures show an implant in the form of a stent 1 and the balloon catheter 60 of a medical system for the treatment of stenoses in intracranial blood vessels. In particular, the stent 1 has a mesh structure 10 which is compressible and expandable. In other words, the mesh structure 10 may take up a delivery state in which the mesh structure 10 has a relatively small cross sectional diameter. The mesh structure 10 is self-expandable, so that the mesh structure 10 can expand by itself to a maximum cross sectional diameter without the influence of external forces. The state in which the mesh structure 10 has the maximum cross sectional diameter corresponds to the neutral state. In this state, the mesh structure 10 does not exert any radial forces.

[0069] Preferably, the mesh structure 10 is one-piece in configuration. In particular, at least sections of the mesh structure 10 may be cylindrical in shape. Preferably, the mesh structure 10 is produced from a tubular blank by laser cutting. In this regard, individual mesh elements or webs 11, 12, 13, 14 of the mesh structure 10 are exposed by the laser cutting process. The regions removed from the blank form cells 30 of the mesh structure 10.

[0070] The cells 30 have a substantially diamond-shaped basic shape. In particular, the cells 30 are delimited by four respective webs 11, 12, 13, 14. The webs 11, 12, 13, 14 in the exemplary embodiment that is depicted here have an at least partially curved profile, in particular S-shaped. Other shapes for the webs 11, 12, 13, 14 are possible.

[0071] As an example, it is possible for the mesh structure to comprise circumferential segments produced from closed cells, wherein the cells are each delimited by four webs which are coupled together at connection points and of which respectively two are adjacent in the circumferential direction UR of the mesh structure and webs coupled together at a connection point have different flexibilities in a manner such that the web with the higher flexibility is more deformable than the web with the lower flexibility upon the transition of the mesh structure from the expanded state into the compressed state, and of which the webs with higher flexibility and the webs with lower flexibility are respectively diagonally opposite in a manner such that two connection points of the cells which are opposite in the longitudinal direction LR of the mesh structure are displaced against one another in the circumferential direction UR during the transition of the mesh structure from the expanded state into the compressed state. In particular, all of the cells of a circumferential segment are identical in configuration in a manner such that the entire mesh structure twists at least in sections during the transition from the expanded state into the compressed state.

[0072] In a further embodiment, the mesh structure may have webs which are connected together into one piece by means of web connectors and delimit closed cells of the mesh structure. The web connectors each have a connector axis which extends between two adjacent cells in the longitudinal direction of the mesh structure. During the transition of the mesh structure from the manufactured state into a compressed state, the web connectors rotate so that an angle between the connector axis and a longitudinal axis of the mesh structure changes upon the transition of the mesh structure from a completely expanded manufactured state into a partially expanded intermediate state, in particular increases. The mesh structure may be configured in one piece. The webs of the mesh structure may, for example, be cut free by laser cutting processing of a tubular blank. The regions which have been cut out from the cells which are delimited by the webs. This is preferably a mesh structure with a closed cell design. The cells are therefore completely surrounded by webs. In particular, the cells may have a substantially diamond-shaped basic shape. In other words, the respective cells are preferably delimited by four webs.

[0073] The web connectors which form a one-piece part of the mesh structure can therefore couple four webs together. The web connectors essentially form points of intersection of the webs.

[0074] During compression or expansion of the mesh structure, the height and the width of the individual cells of the mesh structure change. The degree of change of the height and width of the cells is influenced by the rotation of the web connectors. In particular, the rotation of the web connectors causes a varying, in particular dynamically varying relationship between the cell height and cell width. This leads to a comparatively high flexibility of the mesh structure, in particular in the direction transverse to the axis. In particular, the rotation of the web connectors enables the mesh structure to become oval when guided through narrow hollow organs of the body. The mesh structure, which may have a cylindrical cross section at least in sections, can therefore take up an oval cross sectional geometry at least locally when being passed through a contorted vessel.

[0075] The cells 30 each have cell tips 31, 32 which form the corner points of the diamond-shaped basic shape. The cell tips 31, 32 are respectively disposed at web connectors 20 which each connect four webs 11, 12, 13, 14 together into one piece. Four respective webs 11, 12, 13, 14 extend from each web connector 20, whereupon two cells 30 are associated with each web 11, 12, 13, 14. The webs 11, 12, 13, 14 respectively delimit the cell 30.

[0076] FIG. 1 shows the mesh structure 10 in the neutral state. It can readily be seen that the web connectors 20 are substantially respectively disposed on a common circumferential line. Overall, then, a plurality of cells 30 form a cell ring 34 in the circumferential direction of the mesh structure 10. A plurality of cell rings 34 connected together in the longitudinal direction form the entire mesh structure 10. In the exemplary embodiment shown, the cell rings 34 each comprise six cells 30. In this regard, it should be noted here that the mesh structure 10 may advantageously be formed by interconnected cell rings which have the same cross sectional diameter.

[0077] When the mesh structure 10 is deployed from the balloon catheter 60, the mesh structure 10 automatically expands radially outwardly. In this regard, the mesh structure 10 passes through a plurality of levels of expansion until the mesh structure 10 reaches the implanted state. In the implanted state, the mesh structure 10 preferably has a cross sectional diameter which is approximately 10% to 30%, in particular approximately 20% smaller than the cross sectional diameter of the mesh structure 10 in the neutral state. Thus, in the implanted state, the mesh structure 10 preferably exerts a radial three on the surrounding vessel walls. The implanted state is also described as the “intended use configuration”.

[0078] As can readily be seen in FIG. 1, radiographic implant markers 50 are provided on the stent 1. The radiographic implant markers 50 are disposed at cell tips 31, 32 on the edge cells 30 of the mesh structure 10. Specifically, the radiographic implant markers 50 may be formed as radiopaque sheaths, for example produced from platinum or gold, which are crimped onto the cell tips 31, 32 of the edge cells 30. In FIG. 1, it can be seen that each longitudinal end of the mesh structure 10 has three respective radiographic implant markers 50.

[0079] The mesh structure 10 of FIG. 1 can be divided into three sections. Two edge sections, which are each formed by two cell rings 34, are connected via a central section which comprises five cell rings 34. The cells 30 of the central section essentially have a diamond-shaped geometry, wherein all of the webs 11, 12, 13, 14 of the cells 30 of the central section have substantially the same length. The edge cell rings 34 each comprise cells 30 in which two of the immediately adjacent webs 11, 12, 13, 14 in the circumferential direction are each longer in configuration than the two webs 11, 12, 13, 14 of the same cell 30 which are adjacent in the axial direction. In this manner, the edge cells 30 essentially form a kite-like basic shape.

[0080] The medical device of FIG. 1 furthermore comprises a covering 40 which is disposed on an outside of the mesh structure 10. The covering 40 bridges the entire mesh structure 10 and in particular covers the cells 30. The covering 40 is produced from an electrospun fabric and is therefore characterized by a particularly thin wall. At the same time, the covering 40 is sufficiently stable to follow an expansion of the mesh structure 10. Preferably, the covering 40 is completely and securely connected to the mesh structure 10. Specifically, the covering 40 is preferably bonded to the webs 11, 12, 13, 14, for example by means of a bonding agent.

[0081] The covering 40 may extend over the entire mesh structure 10, as can be seen in FIG. 1. Alternatively, it is possible for the covering 40 to extend over only a portion of the mesh structure 10. As an example, edge cells 30 at one axial end or at both axial ends of the mesh structure 10 may be without a covering. In this regard, the covering 40 may stop before the last or penultimate cell ring 34 of the mesh structure 10. The cell rings 34 which are without a covering allow for good coupling to a transport wire. The region of the stent which has the covering 40 can be highlighted by further radiographic implant markers. It is also possible for radiopaque material to be incorporated into the covering.

[0082] The construction of the covering 40 can readily be discerned from the microscope images of FIGS. 2 and 3. These show that the covering 40 has a plurality of irregularly sized pores 41 which are each delimited by filaments 42. By means of the electrospinning process, a plurality of filaments 42 are formed which are orientated in an irregular manner with respect to each other. The pores 41 are formed in this manner. FIG. 2 also shows that the pores 41 have comparatively small pore sizes, wherein some pores 41 are sufficiently large, however, to ensure blood permeability. Specifically, in FIG. 2, four pores 41 with a size of more than 30 μm.sup.2 have been graphically highlighted. The density of the pores 41 with a size of more than 30 μm.sup.2 indicates that the covering has at least 10 pores 41 of this type over an area of 100000 μm.sup.2.

[0083] FIG. 3 shows a further exemplary embodiment of a covering 40, in which a generally larger pore size has been set. It can be seen that some pores 41 have a size of more than 30 μm.sup.2 wherein, however, a pore size of 300 μm.sup.2 is not exceeded.

[0084] FIGS. 2 and 3 respectively show that the filaments 42 of the covering 40 intersect multiple times. A particular feature of the electrospinning process is, however, that in the covering 40, sites are present at which exclusively two filaments intersect, i.e. no more than two filaments 42 intersect. It is clear from this that the overall covering 40 has very thin walls and is therefore highly flexible.

[0085] The high flexibility of the covering 40 in combination with the high flexibility of the mesh structure 10 means that a stent 1 can be provided which can be introduced into a blood vessel through a very small balloon catheter 60. In particular, the balloon catheter 60 may have a size of 6 French, in particular at most 5 French, in particular at most 4 French, in particular at most 3 French, in particular at most 2 French. Specifically, in the exemplary embodiments described herein, the stents 1 in accordance with the exemplary embodiments described here may be combined with balloon catheters 60 which have an internal diameter of at most 991 μm (0.039 inches), in particular at most 686 μm (0.027 inches), in particular at most 635 μm (0.025 inches), in particular at most 533 μm (0.021 inches), in particular at most 432 μm (0.017 inches), in particular at most 406 μm (0.016 inches), in particular at most 381 μm (0.015 inches), in particular at most 330 μm (0.013 inches).

[0086] The layer thickness of the covering 40 in particularly preferred variations is at most 6 μm, in particular at most 4 μm, in particular at most 2 μm. In this, at most 4, in particular at most 3, in particular at most 2 filaments 42 intersect. In general, within the electrospun structure of the covering 40, points of intersection are present in which only 2 filaments 42 intersect.

[0087] Preferably, the mesh structure 10 has a cross sectional diameter in the neutral state of between 2.0 mm and 10 mm, in particular between 2.5 mm and 7 mm, in particular between 2.5 mm and 6 mm, in particular between 4.5 mm and 6 mm, in particular between 3.0 mm and 5 mm, in particular approximately 3.5 mm or approximately 4.5 mm. In general, the mesh structure 10 for the treatment of vulnerable plaques or soft plaques in intracranial blood vessels, for example the internal carotid artery (arteria carotis interna) or intracranial vessels distally therefrom, preferably has a cross sectional diameter of at most 6 mm, in particular between 2.5 mm and 5.5 mm. For the treatment of vulnerable plaques or soft plaques, preferably also for the treatment of stenoses, in extracranial blood vessels, in particular in extracranial sections of the carotid artery, for example the external carotid artery (arteria carotis externa), the mesh structure 10 may have a cross sectional diameter of at most 10 mm, in particular between at least 6 mm and at most 10 mm, in the neutral state.

[0088] FIG. 4 shows a braided mesh structure 10 which, in a preferred exemplary embodiment, can form a support for a covering 40. The braided mesh structure 10 is formed by a single wire 16 which is braided into a tube. The wire ends are connected within the mesh structure 10 with a connecting element 18.

[0089] The wire 16 has a plurality of sections which are designated as mesh elements 11, 12, 13, 14. Each section of the wire 16 which runs between two points of intersection 19 is described as an autonomous mesh element 11, 12, 13, 14. Clearly, four respective mesh elements 11, 12, 13, 14 delimit a mesh or cell 30.

[0090] The braided mesh structure 10 has flaring axial ends which are described as flares 17. The wire 16 is turned around in each flare 17 and forms end loops 15. Overall, in the exemplary embodiment shown, six end loops 15 are provided at each flare 17. Alternate end loops 15 carry an implant X-ray marker 50 in the form of a crimp sheath. Thus, three respective implant X-ray markers 50 are present on each axial end of the mesh structure 10.

[0091] FIGS. 5 and 6 show an exemplary embodiment of the stent 1 at different magnifications of a scanning electron microscopic image. The stent comprises a mesh structure 10 in accordance with FIG. 4 which is formed with a covering 40 produced from an electrospun fabric. The covering 40 is disposed on an outside of the tubular mesh structure 10.

[0092] FIG. 5 shows a 500-times magnification of a region of the device which comprises a cell tip 32 of the mesh structure 10. Two mesh elements or webs 11, 13 of a cell 30 meet in the cell tip 32. The covering 40 covers the webs 11, 12. It can be seen that the covering 40 has a plurality of different-sized pores 41, i.e. completely free through openings. The 3500-times magnification of FIG. 6 shows a section of the covering 40 of FIG. 5 in detail. The path of the individual filaments 42 of the electrospun fabric can clearly be seen. The filaments 42 delimit pores 41, wherein the pores 41 are irregular in configuration. However, it can be seen that some pores 41 have a larger open area than other pores 41. The larger pores 41 enable nutrients to pass through the covering 40.

[0093] FIG. 7 shows a balloon catheter 60 for delivering the stent 1 to a blood vessel. The balloon catheter 60 comprises two channels 61, 62. It is also possible to provide more than two channels 61, 62, for example three, four or more than four channels 61, 62.

[0094] The balloon catheter 60 furthermore comprises a balloon 63 which is disposed in the distal region of the channels 61, 62. As illustrated in FIG. 7, as well as in FIGS. 10 and 11, the balloon 63 is provided in the region of the catheter tip. The balloon 63 is at a distance from the outlet opening 64 of the delivery channel 62, so that a balloon-free section of the delivery channel 62 is formed between the outlet opening 64 and the distal balloon end 69. The balloon 63, in particular a proximal end 68 of the balloon 63, is in fluid communication with an inflation channel 61, as can be seen in FIGS. 10 and 11. The balloon 63 and the inflation channel 61 are aligned in the extended state of the balloon catheter 60. In order to connect the inflation channel 61 to the balloon 63, the wall of the inflation channel 61 is extended and transitions into the balloon wall. The transition between the inflation channel 61 and the balloon 63 is made by a continuous enlargement of the diameter between the inflation channel 61 and the maximum external circumference of the balloon 63 in the expanded state (see FIG. 10, FIG. 11).

[0095] The inflation channel 61 and the balloon 63 are formed as one piece. It is also possible to make the balloon 63 and the inflation channel 61 in two pieces and to provide an additional connecting piece between the balloon 63 and the inflation channel 61.

[0096] The connection in accordance with FIGS. 10 and 11 is particularly suitable for a coaxial arrangement of the two channels 61, 62 in accordance with FIG. 8. Here, the annular gap 72 between the two channels 61, 62 transitions into the internal volume of the balloon 63. The connection between the inflation channel 61 and the balloon 63 may be different, for example if the two channels 61, 62 are disposed adjacent to each other, as can be seen in FIG. 9. In this case, the connection between the balloon 63 and the inflation channel 61 is disposed laterally of the delivery channel 62 (not shown).

[0097] The inflation channel 61 serves to supply the balloon 63 with a fluid or for removal of the fluid from the balloon 63. As an example, the fluid may be a common salt solution or sterile water. The fluid may also be gaseous, for example ambient air. In practice, the fluid is frequently an air/liquid mixture.

[0098] The balloon catheter 60 comprises a delivery channel 62 with an outlet opening 64. The outlet opening 64 is disposed distally and connects the delivery channel 62 with the environment, in particular with the blood vessel, in which the stent 1 has been deployed. The outlet opening 64 as well as the internal diameter of the delivery channel 62 are adapted in a manner such that the delivery channel 62 has a retaining function in respect of the stent 1 disposed in the delivery channel 62. This means, for example, that the wall of the delivery channel 62 is strong enough to be able to accommodate the radial forces exerted by the self-expandable stent 1. Furthermore, the delivery channel 62 is sufficiently flexible for the catheter tip to be able to fit relatively narrow, contorted vessels.

[0099] As can be seen in FIGS. 7, 10 and 11, the delivery channel 62 extends through the balloon 63. This means that the balloon 63 is disposed around the outer circumference 71 of the delivery channel 62. The delivery channel 62 and the balloon 63 are disposed coaxially.

[0100] The association of the balloon 63 with the delivery channel 62, which is adapted for the delivery of the stent 1, has the advantage that the balloon catheter 60 has a dual function. Firstly, the balloon catheter 60 serves to deliver the stent 1 through the delivery channel 62. Secondly, by means of the balloon 63 disposed in the region of the catheter tip, the dilation or widening of the vessel which is required can be carried out without needing to change a catheter. In order to apply this principle, it may be sufficient for the delivery channel 62 to be generally associated with the balloon 63 and in fact in the region of the catheter tip, so that the balloon catheter 60 can be used both to deploy the stent 1 as well as for dilation, in particular pre-dilation of the stenosis and/or for post-widening of the implanted stent 1. The symmetrical arrangement of the delivery channel 62 and the balloon 63, as can be seen in FIGS. 7, 10 and 11, has the advantage that a simple radial widening of both the vessel as well as of the implanted stent 1 is possible, whereupon the delivery channel 62 is protected from the balloon 63 or, upon widening the balloon 63, it does not come into contact with the vessel or with the implanted stent 1.

[0101] The dual function of the balloon catheter 60 is achieved in that the delivery channel 62 is connected to a proximally disposed connector which is extracorporeal in use, which is adapted for introducing the stent 1 into the delivery channel 62. This means in practice that the extracorporeal connector is disposed at the proximal end of the catheter line 70, i.e. remote from the catheter tip. The extracorporeal connector for the delivery channel 62 is therefore directly accessible by the user. The connector may, for example, be adapted for loading the stent 1, wherein the stent 1 is moved from the extracorporeal connector up to the catheter tip through the delivery channel 62. As an alternative, the extracorporeal connector may be used in cooperation with a pre-loaded stent which is located in the region of the catheter tip, whereupon an actuating element can be moved through the extracorporeal connector and the delivery channel 62, for example a pusher or a guidewire with a slightly larger diameter than the stent 1, which is pushed ahead up to the pre-loaded stent 1 and then cooperates with it for deployment. The extracorporeal connector for the delivery channel 62 may comprise a loading lock for stents 1 which is known per se. The connector may be a Luer connector, for example.

[0102] As can be seen in FIG. 8, in one exemplary embodiment, the delivery channel 62 is coaxially disposed in the inflation channel 61. In this regard, an annular gap 72 is formed between the two channels 61, 62, which functions as a control lumen for the balloon 63. The delivery channel 62 which is disposed inside the inflation channel 61 forms the main lumen through which the stent 1 is moved.

[0103] FIG. 9 shows an alternative arrangement of the two channels 61, 62, wherein the working channel 61 and the delivery channel 62 are disposed adjacent to each other, in particular parallel to each other. Around the two channels 61, 62 is a catheter line 70 which fixes the arrangement of the two channels 61, 62. In general, the diameter of the delivery channel 62 is preferably larger than the diameter of the inflation channel 61.

[0104] FIGS. 10 and 11 show that the distal balloon end 69 is in fluid communication with the outer circumference 71 of the delivery channel 62. The proximal balloon end 68 is in fluid communication with the inflation channel 61. In this way, the balloon 63 has a tight fluid seal with the delivery channel 62, and on the other band can be inflated or deflate via the inflation channel 61.

[0105] The inflation channel 61 is connected to a proximally disposed connector which is extracorporeal in use. In the context of the extracorporeal connector for the delivery channel 62, a multiple connection, for example a Y Luer connector, is possible. The connector for the inflation channel 61 is either securely connected or releasably connected or connectable to a pressure device. The pressure device is configured to produce an over-pressure in order to inflate or to produce an under-pressure in order to deflate the balloon 63. The pressure device may, for example, comprise a syringe. Other pressure devices are possible.

[0106] The delivers/channel 62 is provided with a friction-reducing inner surface for movement of the stent 1 in translation in the delivery channel 62. Examples of a material for the inner surface are PTFE, FEP or HDPE or similar friction--reducing surface modifications. Other materials for the coating are also possible.

[0107] FIG. 11 shows that the catheter tip has a plurality of X-ray markers 65, 66, 67. A first X-ray marker 65 is disposed in the region of the distal outlet opening 64 and serves for the localisation of the end of the catheter tip. A second X-ray marker 66 is disposed in the region of the distal balloon end 69. A third X-ray marker 67 is disposed in the region of the proximal balloon end 68. The second and third X-ray markers 66, 67 act to establish the position of the balloon 63.

[0108] The catheter tip may be configured atraumatically and/or flexibly.

[0109] Suitable materials for the balloon catheter 60 are plastics, metals, shape memory materials such as nitinol, as well as radiopaque materials.

[0110] Furthermore, by means of the delivery channel 62, the balloon catheter 60 allows aspiration during or after dilation of the stenosis. In this regard, the delivery channel 62 is connected or connectable to a suction device. This has the advantage that particles of the vessel wall which become detached upon dilation can be sucked away through the delivery channel 62.

[0111] It is also possible to inject a contrast agent through the delivery channel 62. Specifically, after dilation of the stenosis, the delivery channel 62 of the balloon catheter 60 can be used to dispense the contrast agent in order to check whether the stenosis has been opened up. In this regard, the delivery channel 62 is connectable to or connected to an appropriate device for injection of a contrast agent, for example a syringe.

[0112] Furthermore, the balloon catheter 60 has the advantage that by means of a single balloon catheter 60, a plurality of stenoses can be dilated and/or a plurality of stents 1 can be deployed. A further advantage of the balloon catheter 60 is that upon dilation of the balloon 63, the delivery channel 62 does not collapse because it has an inherent stable channel wall.

[0113] The combination of the balloon catheter 60 described here with the stent 1 described here which has an electrospun covering 40 has been shown to be particularly advantageous in the treatment of stenoses. On the one hand, good pre-dilation of the stenosis is possible by means of the balloon catheter. On the other hand, good post-dilation can also be obtained. The stent 1 supports the dilated blood vessel well and in particular stabilizes vulnerable plaques because of its particularly flexible and dense covering 40. Furthermore, the stent 1 with its covering 40 permits good endothelial cell formation, which further stabilizes the dilated blood vessel.

LIST OF REFERENCE INDICATORS

[0114] 1 stent

[0115] 10 mesh structure

[0116] 11, 12, 13, 70 web or mesh element

[0117] 15 end loop

[0118] 16 wire

[0119] 17 flare

[0120] 18 connecting element

[0121] 19 point of intersection

[0122] 20 web connector

[0123] 30 cell

[0124] 31, 32 cell tip

[0125] 34 cell ring

[0126] 40 covering

[0127] 41 pore

[0128] 42 filament

[0129] 50 implant X-ray marker

[0130] 60 balloon catheter

[0131] 61 inflation channel

[0132] 62 delivery channel

[0133] 63 balloon

[0134] 64 distal outlet opening

[0135] 65 first X-ray marker

[0136] 66 second X-ray marker

[0137] 67 third X-ray marker

[0138] 68 proximal balloon end

[0139] 69 distal balloon end

[0140] 70 catheter line

[0141] 71 outer circumference

[0142] 72 annular gap