Medical implant

Abstract

The invention relates to a medical implant (10) for treating a local lesion (100) in a vessel, in particular for treating a bifurcation aneurysm (100), comprising a support body (11), which can be compressed and expanded, wherein the support body (11) comprises at least a proximal section (12) and a distal section (13), which are substantially tubular, in particular cylindrical, and connected to one another via a transition section (14), wherein the proximal section has a first porosity (12a) and the distal section (13) has a second porosity (13a), which is lower than the first porosity (12a), wherein the transition section (14) has a porosity that changes in the axial direction, wherein the first and second porosity (12a, 13a) merge into one another in the transition section (14), and wherein the transition section (14) can be positioned in the vessel in such a way that the blood flow can be at least partially diverted from the lesion (100) by the second porosity (13a) and the blood flow into an outgoing vessel (101) can be at least substantially maintained by the first porosity (12a).

Description

[0001] Acandis GmbH September 3, 2025 M / CAN-425-PC JK / AS / pk

[0002] Medical implant

[0003] Description

[0004] The invention relates to a medical implant for treating a local lesion in a vessel, in particular for treating a bifurcation aneurysm, comprising a support body that is compressible and expandable. A medical implant according to the preamble of claim 1 is known, for example, from EP 3 244 843 A1.

[0005] To treat vascular lesions such as aneurysms, medical implants, such as flow diverters, are used to reduce blood flow into the lesion, allowing the blood within the lesion to coagulate, possibly with the aid of an embolic agent. Due to the implant's position within the vessel, particularly at a bifurcation, blood flow into a branching vessel may be restricted. This can lead to an insufficient supply of nutrients to the downstream tissue areas.

[0006] From the aforementioned EP 3 244 843 A, for example, a treatment system for bifurcation aneurysms is known in which at least two implants are inserted in the region of a bifurcation to treat the aneurysm and largely maintain blood flow into a branching vessel. However, this treatment system is very complex.

[0007] The invention is therefore based on the objective of providing a medical implant for the treatment of a lesion of a vessel, which on the one hand enables the treatment of the lesion and on the other hand maintains the blood flow into outgoing vessels at least to a large extent.

[0008] According to the invention, this problem is solved by a medical implant having the features of claim 1. M / CAN-425-PC

[0009] 2

[0010] Specifically, the problem is solved by a medical implant for treating a local lesion in a vessel, particularly a bifurcation aneurysm, with a support body that is compressible and expandable. The support body comprises a proximal section and a distal section, which are essentially tubular, particularly cylindrical, and connected by a transition section. The proximal section has a first porosity, and the distal section has a second porosity that is smaller than the first. The transition section has a porosity that changes in the axial direction, with the first and second porosities merging into one another within the transition section.The transition section can be positioned in the vessel in such a way that the blood flow through the second porosity can be at least partially deflected from the lesion and the blood flow into a branching vessel through the first porosity can be at least largely maintained.

[0011] The invention has several advantages.

[0012] The medical implant according to the invention enables efficient treatment of a local lesion without significantly affecting blood flow into a branching vessel near the lesion. For this purpose, the implant has a support body designed to fulfill both functions. Specifically, the proximal section of the support body has a first porosity that is larger than the second porosity of the distal section. While the lower porosity of the distal section, when implanted, serves to divert blood flow away from the lesion, the greater porosity of the proximal section ensures that blood flow into branching vessels located near the lesion is largely maintained. In other words, the second porosity is sufficiently blood-tight to reduce blood flow into the lesion, and the first porosity is sufficiently blood-permeable to maintain blood flow into the branching vessel.

[0013] The arrangement and length of the first and second porosities along the longitudinal axis of the support body, as well as the size of the first and second porosities, are adjustable such that both functions, i.e., diverting blood flow away from the lesion and maintaining blood flow into an outgoing M / CAN-425-PC

[0014] 3

[0015] The vessel can be filled. This makes the implant adaptable to different vascular anatomies.

[0016] Advantageously, the first porosity is greater than the second porosity both in the (fully expanded) unloaded state and in the implanted state within a vessel.

[0017] The first and second porosities are preferably essentially constant along the longitudinal axis or in the axial direction of the proximal and distal sections. In other words, the first and second porosities are essentially uniform over the entire length of the respective section. It is possible for the first and second porosities to change in the axial direction. In this case, the change in the first and second porosities is preferably designed such that the distal section is sufficiently blood-tight and the proximal section is sufficiently blood-permeable over its entire length.

[0018] The first and second porosities merge in a transition section connecting the proximal and distal sections. This transition section exhibits a porosity that changes axially. In other words, the transition section has variable porosity. The porosities of the proximal and distal sections can merge discretely, i.e., in several small steps, or continuously, i.e., without steps, within the transition section. Preferably, the porosity of the transition section increases in the proximal direction and decreases in the distal direction.

[0019] If the proximal and distal sections exhibit a porosity that changes in the axial direction, the change in porosity in the transition section is more pronounced than in the proximal and distal sections. In particular, the change in porosity in the transition section is at least 20% greater than the change in porosity in the proximal and distal sections.

[0020] The transition section preferably exhibits at its proximal longitudinal end the porosity of the proximal section, i.e. the first porosity, and at its distal longitudinal end the porosity of the distal section, i.e. the second M / CAN-425-PC

[0021] 4

[0022] Porosity. Between the proximal and distal longitudinal ends, the transition section exhibits a porosity that changes in the axial direction to create the transition between the first and second porosity.

[0023] The changing porosity of the transition zone ensures that the implant or support body can be retracted into a delivery device, particularly a catheter (resheatability). An abrupt transition between the first and second porosities would cause the support body to bulge or buckle at the point of the abrupt transition during retraction, thus blocking or impairing the retraction process. By incorporating a transition zone that prevents an abrupt change between the porosities, the retractability of the implant can be guaranteed. This allows a surgeon to precisely position the implant so that the first porosity ensures blood flow into an outgoing vessel, while the second porosity reduces blood flow into the lesion.

[0024] The transition section, i.e., the transition between the first and second porosities, can be positioned within the vessel in such a way that both functions of the implant—diverting blood flow away from the lesion and maintaining blood flow into a branching vessel—can be fulfilled. This can be achieved by positioning the transition section, in its implanted state, between the lesion and the branching vessel. In other words, the lesion can be covered only by the distal section (second porosity), and the branching vessel only by the proximal section (first porosity). Alternatively, the transition section can extend at least partially into the area of ​​the lesion or the branching vessel.

[0025] In particular, the medical implant is suitable for treating lesions located at or near a bifurcation. Such a bifurcation can include at least one main vessel and at least two branching tributaries. The distal portion of the implant can be positioned in one of the tributaries in such a way that the aneurysm is at least partially covered and blood flow into the aneurysm is reduced by the porosity of the distal portion. The proximal portion can be M / CAN-425-PC

[0026] 5. The junction is positioned in the main vessel of the bifurcation such that it spans the collateral vessel, maintaining blood flow into the collateral vessel through the porosity of the proximal segment. The junction can be positioned in the bifurcation in such a way that it fulfills the functions of both the proximal and distal segments.

[0027] For example, the implant can be placed in a bifurcation where the branches leading from the main vessel each form an angle between 20° and 110° with the main vessel. In other words, the medical implant can be flexible enough to be positioned in a bifurcation with a vessel angle between 20° and 110°. It is also conceivable that the implant could be positioned in a vessel without branches that forms an angle between 20° and 110°.

[0028] The proximal and distal sections are essentially tubular in shape. In particular, the proximal and distal sections are essentially tubular in their manufactured state. The proximal and distal sections are preferably tubular in shape to allow adaptation to a vessel wall when implanted. The tubular shape can also include a conical form of the proximal and distal sections. Furthermore, barrel bulges or flared longitudinal ends can be included. Preferably, the proximal and distal sections are at least partially cylindrical.

[0029] The proximal section is preferably that section of the support body which is detachably connected to a transport wire for introducing the implant into a vessel. The distal section is preferably that section of the support body which, when introducing the implant with a delivery device, in particular a catheter, is the first part to exit the delivery device.

[0030] The medical implant or support structure preferably has a lattice structure made of lattice elements, in particular a tubular wall made of a lattice structure. The porosity preferably describes the ratio of the projected surface area of ​​the lattice elements to the total surface area of ​​the support structure. M / CAN-425-PC

[0031] 6

[0032] The grid structure can be a mesh of braided wires or a single braided wire forming meshes. Alternatively, the grid structure can be a monolithic grid structure made of struts, for example, a laser-cut grid structure.

[0033] Preferred embodiments of the invention are specified in the dependent claims.

[0034] Preferably, the first and second porosities in the transition section merge essentially continuously in the axial direction. In other words, the transition from the first to the second porosity through the transition section can be essentially continuous. Furthermore, the porosity in the transition section between the first and second porosities can change essentially continuously. Preferably, the porosity of the transition section increases essentially continuously in the proximal direction, or the porosity decreases essentially continuously in the distal direction. The continuous transition from the first to the second porosity improves the retractability of the implant into a delivery system, as it prevents bulging of the support body during retraction in the region of the porosity transition.

[0035] The support body can have a braided structure forming meshes, with the transition section preferably having a mesh size that changes in the axial direction. The braided structure can be formed from wires that are preferably wound around a longitudinal axis of the support body, interlacing and crossing each other to form meshes. These meshes advantageously determine the porosity of the support body. The larger the meshes, the higher the porosity. The mesh size of the proximal section is preferably larger than the mesh size of the distal section. In the transition section, the mesh size of the proximal section preferably approaches the mesh size of the distal section. This approximation can be easily achieved by changing various braiding parameters in the transition section.

[0036] The transition section can have a length of at least 2 meshes in the axial direction, in particular at least 3 meshes, in particular at least 4 M / CAN-425-PC

[0037] 7

[0038] The mesh structure ensures that the transition section is sufficiently long to allow for a smooth, and in particular continuous, transition between the first and second porosities. This improves the retractability of the implant into a delivery system.

[0039] Furthermore, the transition section can have an axial length between 1 mm and 12 mm, in particular at least 3 mm, in particular at least 5 mm, in particular at least 7 mm, in particular at least 9 mm, in particular at least 11 mm. Other lengths of the transition section are possible. For example, the transition section can have an axial length of 15 mm, in particular 20 mm, in particular 25 mm. In particular, the length of the transition section can be adapted to the vascular anatomy such that, in the implanted state, the transition section is positioned between the lesion and an offshoot vessel.

[0040] The proximal and / or distal section preferably has an axial length between 4 mm and 12 mm, in particular at least 5 mm, in particular 6 mm, in particular 7 mm, in particular 8 mm, in particular 9 mm, in particular 10 mm, in particular 11 mm. Alternatively, the proximal and / or distal section may have a different length. For example, the proximal and / or distal section may have an axial length of 15 mm, in particular 20 mm, in particular 25 mm. This allows the length of the proximal and / or distal section to be adapted to different anatomies in the area of ​​a lesion.

[0041] The implant or support body can have an axial length between 8 mm and 40 mm, particularly between 15 mm and 25 mm. Other lengths of the implant or support body are possible.

[0042] Advantageously, the ratio of the mesh size of the proximal section to the mesh size of the distal section is between 1.5 and 10, in particular 2, in particular 3, in particular 4, in particular 5, in particular 6, in particular 7, in particular 8, in particular 9. The mesh size advantageously defines the porosity of the support body. Such a ratio between the first and second porosity or the mesh size has proven to be M / CAN-425-PC

[0043] 8 particularly advantageous in order to best fulfill the two functions, i.e., diverting the blood flow away from the lesion and maintaining the blood flow into an outgoing vessel.

[0044] The proximal section preferably has a mesh size between 0.2 mm and 1 mm, particularly at least 0.4 mm, particularly at least 0.6 mm, and particularly at least 0.8 mm. This advantageously allows sufficient blood permeability to be achieved so that blood flow into an outgoing vessel can be maintained. Furthermore, this allows the outgoing vessel to be accessed through the mesh with a treatment device, for example, a catheter, particularly a 2-French catheter.

[0045] In a preferred embodiment, the first porosity is between 3% and 30%, in particular at least 5%, in particular at least 10%, in particular at least 15%, in particular at least 20%, in particular at least 25%, larger than the second porosity. The second porosity is preferably substantially impermeable to blood, while the first porosity is preferably sufficiently permeable to blood flow. It has been advantageously found that the first porosity is sufficiently permeable to blood when it is between 3% and 30% larger than the second porosity.

[0046] The transition section can be tubular, particularly cylindrical, or conical. Preferably, this means that the transition section can have either a constant or a variable diameter in the axial direction. If the transition section is conical, it has an opening angle relative to the longitudinal axis of the support body. Furthermore, if conical, the transition section can be tapered either distally or proximally. An advantage here is that the porosity of the transition section can be easily changed by altering its diameter or tapering. If the transition section is made of braided wires, the wires move closer together as the diameter of the transition section decreases, thereby reducing the porosity. M / CAN-425-PC

[0047] 9

[0048] Furthermore, the proximal section can have a different, and in particular a larger, cross-sectional diameter than the distal section. This is especially true if the transition section is conical. A conical transition section allows the proximal and distal sections to be connected even if they have different diameters. For example, the cross-sectional diameter of the proximal section can be at least 1.5 times, in particular 2 times, in particular 2.5 times, or in particular 3 times larger than the cross-sectional diameter of the distal longitudinal end. The advantage here is that the size or cross-sectional diameter of the proximal and distal sections can be selected in such a way that the implant can be adapted to different vascular anatomies, especially in the region of a bifurcation.In particular, the diameters of the proximal and distal sections can be selected to ensure good wall adaptation in the implanted state. It is also conceivable that the distal section has a larger cross-sectional diameter than the proximal section.

[0049] The implant or support body can have a cross-sectional diameter between 2.5 mm and 8 mm, in particular between 3 mm and 6 mm. For example, the implant or support body can have a cross-sectional diameter of at least 4 mm, in particular at least 5 mm, and in particular at least 7 mm. Furthermore, the implant or support body can have a cross-sectional diameter of at most 10 mm, in particular at most 9 mm.

[0050] Preferably, the braided structure is formed from wire strands, wherein the wire strands of the distal section are each formed from a single wire, and the wire strands of the proximal section and / or the transition section are formed from at least two wires bundled together, in particular combined to form a double wire. The mesh size can be changed by combining two or more single wires into multiple wires or double wires. In particular, those sections of the support body that have multiple wires have a larger mesh size than those sections that comprise single wires. M / CAN-425-PC

[0051] 10

[0052] It is also possible that the wires in the proximal section and / or the transition section are bundled into triple or quadruple wires. In other words, a wire strand in the proximal section and / or the transition section can consist of three or four wires. A different number of wires per wire strand is possible.

[0053] Even in the distal section, individual wires within a wire strand can be bundled together to form multiple wires. In this case, it is preferable if a larger number of wires are bundled together in a wire strand in the proximal section and / or the transition section than in the distal section.

[0054] The number of wires can be adapted to the specific application. The radial force, and therefore the support effect of the implant, as well as the porosity of the support body, can be influenced by the number of wires. For example, the support body may contain between 24 and 64 wires, particularly 48.

[0055] It is possible that the distal section has a different, particularly a larger, number of wires than the proximal section and / or the transition section. For example, additional wires may be woven into the distal section. Alternatively or additionally, additional wires may be woven into the transition section. This allows for individual adjustment of the porosity of each section. For instance, increasing the number of wires can reduce the porosity. This is particularly advantageous for adjusting the porosity of the distal section to reduce blood flow into an aneurysm once implanted.

[0056] The grouping of wires can be referred to as tufting. Tufting can, in particular, mean that at least two wires are laid next to each other in the same plane. At least two wires can be arranged side by side on a circumferential plane, forming a wire strand. A braided structure can be created from these strands to form a wall, with the individual wire strands being interwoven. Through tufting, the braid or wall can be composed of different areas along the longitudinal axis of the supporting structure. Tufting, i.e., the formation of flat wire strands with different M / CAN-425-PC

[0057] 11

[0058] The number of wires allows, for example, the production of areas with different radial forces and mesh sizes. With regard to the application of this technology, reference is made to DE 10 2007 053 070 B4, which originates from the applicant.

[0059] Furthermore, the wires advantageously have a braiding angle relative to the longitudinal axis of the support body, with the wires in the proximal section having a different, and in particular a smaller, braiding angle than the wires in the distal section. In other words, the braiding angle is determined by the inclination of the wires relative to the longitudinal axis. It is advantageous here that the porosity of the support body can be easily adjusted by the braiding angle. Particularly preferably, the wires in the distal section have a larger braiding angle than the wires in the proximal section. Consequently, the porosity in the distal section is preferably lower than in the proximal section. This allows for good coverage of the lesion in the distal section.

[0060] The wires in the proximal section preferably have a braiding angle between 45° and 60°, particularly 55°. Such a braiding angle in the proximal section is particularly preferred because the porosity can be adjusted to ensure, on the one hand, good support and thus good anchorage in the vessel, and on the other hand, that blood flow into an outgoing vessel is maintained.

[0061] The wires in the distal section can have a braiding angle between 60° and 80°, particularly 75°. Such a braiding angle in the distal section is particularly preferred because the porosity can be adjusted so that the blood flow can be at least partially diverted away from the lesion.

[0062] The braiding angles in the proximal and distal segments can be essentially constant. In other words, the proximal and distal segments can exhibit essentially the same braiding angle along their entire length. An essentially constant braiding angle can also include a change in the braiding angle that is so small as to fulfill the functions of each segment, namely, diverting blood flow away from a lesion through the distal segment and maintaining blood flow into an outgoing vessel through the proximal segment. M / CAN-425-PC

[0063] 12

[0064] In a preferred embodiment, the braiding angles of the proximal and distal sections merge into one another in the axial direction, particularly in a substantially continuous manner, within the transition section. This is preferably understood to mean that the braiding angle increases substantially continuously from proximal to distal within the transition section. Within the transition section, the wires preferably change their braiding angle such that the first porosity is present in the proximal section and the second porosity in the distal section. A substantially continuous change in the braiding angle allows for a continuous change in porosity along the longitudinal axis of the transition section.

[0065] Besides the braiding angle, the porosity in the transition section can be influenced by the number of wires, the wire diameter, and / or the outer diameter of the support body. Similar principles apply to the porosity of the proximal and distal sections.

[0066] The mesh size, which in a preferred embodiment determines the porosity, can also be influenced by the wire braiding angle, the wire diameter, the number of wires, the number of wire plies, and / or the outer diameter of the support body. Preferably, the meshes are maximally large when the wires of a mesh form an angle of 90° to each other. In this case, the meshes essentially form a rectangle or square. Such large meshes can, for example, be provided in the proximal section to maintain blood flow into an outgoing vessel. In the distal section, i.e., the section that, in the implanted state, is positioned at the lesion, the mesh size is advantageously smaller than in the proximal section. This achieves a high surface coverage in the distal section and thus good shielding of the lesion.

[0067] Preferably, the wires in the distal and proximal sections, as well as in the transition section, are one and the same. In other words, the support body is preferably formed from the proximal to the distal longitudinal end using the same wires. The insertion of additional wires, for example to achieve a change in porosity, is not necessary, but also not excluded. M / CAN-425-PC

[0068] 13

[0069] The wires can form closed loops at a proximal longitudinal end of the support body. This is advantageous because the loops generate increased uprighting force at the proximal longitudinal end of the mesh structure, thus ensuring secure anchoring of the support body near the lesion. Furthermore, the closed loops can preferably create a flaring of the diameter at the proximal longitudinal end of the support body. Such radial widening of the proximal longitudinal end can, for example, reduce the risk of stent migration. The wires can also preferably form open ends at a distal longitudinal end of the support body.

[0070] In a preferred embodiment, the support body or the braided structure can be manufactured by first interlacing several wires helically to form the distal section of the support structure, the wires preferably touching only at their intersection points in the distal section. At the boundary between the distal section and the transition section, preferably at least two wires are combined into a single wire strand such that they touch along their longitudinal axis (faceting) or form multiple wires. These multiple wires are then helically braided around the longitudinal axis of the support body to form the transition section. The braiding angle can be varied, among other things, to create the variable porosity of the transition section.At the boundary between the transition section and the proximal section, a specific braiding angle is preferably set to produce or braid the proximal section preferably with a constant braiding angle. At the proximal longitudinal end of the support body, the multiple wires are deflected such that they form closed loops. Subsequently, the multiple wires are helically braided from the proximal section (with a substantially constant braiding angle) through the transition section (with a variable braiding angle) to the boundary between the transition section and the distal section. At this boundary, the multiple wires are again separated into individual wires. The individual wires are braided to the distal longitudinal end of the support body, forming free wire ends there. M / CAN-425-PC.

[0071] 14

[0072] Alternatively, it is conceivable that the bundling of single wires into multiple wires or the dissolution of multiple wires into single wires occurs at the boundary between the transition section and the proximal section. In this case, only the proximal section is formed from multiple wires, while the transition section and the distal section consist of single wires.

[0073] Preferably, the wires are formed from an X-ray-visible core material, in particular platinum or a platinum alloy, and a shape-memory material, in particular a nickel-titanium alloy, wherein the core material has a cross-sectional area of ​​between 10% and 50%, in particular between 20% and 30%, of the wire. The proportion of the core material to the cross-sectional area of ​​the wire depends, for example, on the wire diameter or can be adapted to the wire diameter.

[0074] It is advantageous that the wires exhibit optimal radiolucency due to the core material. This allows, for example, a surgeon to easily determine the implant's position during insertion or once implanted. Platinum or a platinum alloy is particularly preferred as the core material, since these materials offer optimal radiopacity and consequently good radiolucency. As a result, it is unnecessary to use additional marker elements, such as marker sleeves, which can be applied or crimped onto the wire. However, the use of additional marker elements is not precluded.

[0075] If the proximal, distal, and transitional sections each have a different number of radiopaque wires, then the individual sections are advantageously radiopaque to varying degrees. This makes it possible to distinguish the proximal, distal, and transitional sections from one another under X-ray. For example, the transition between the sections is visible under X-ray guidance.

[0076] Furthermore, the radiopaque core material can be encased in a shape memory material. In other words, the surface of the wires is made of a shape memory material. Here, it is advantageous that M / CAN-425-PC

[0077] 15 the implant is self-expanding due to the shape memory material or has self-expanding properties.

[0078] Such wires, which are formed from an X-ray visible core material encased in a shape memory material, are generally known as DFT wires.

[0079] Preferably, the wires have a diameter between 20 pm and 50 pm, particularly 38 pm. These wire diameters advantageously influence the radial force of the support body, thereby achieving optimal expansion and compression behavior. Furthermore, the porosity of the support body can be influenced by the wire diameter.

[0080] Preferably, at least one radiopaque marker is located at the junction between the proximal and distal segments and / or between the distal and distal segments. Alternatively or additionally, at least one radiopaque marker can be located on each segment of the stent body. In other words, the proximal, distal, and distal segments can each have a radiopaque marker. The radiopaque markers ensure optimal radiographic visibility of the stent. This allows for ideal positioning of the stent within the lesion, particularly a bifurcation aneurysm. It makes it easy for the surgeon to estimate where the stent will be placed in the vessel after being released from an introducer.

[0081] For example, it is possible to attach a marker element to the transition segment in such a way that, when implanted, it is positioned in the bifurcation or at the transition between branching vessels. This ensures correct placement of the implant, particularly the transition segment, through optimal radiographic visibility.

[0082] Alternatively or additionally, radiopaque end markers may be provided, particularly at the closed loops of the proximal section.

[0083] In a preferred embodiment, the marker elements can be designed as marker sleeves that are firmly connected to the wire, in particular M / CAN-425-PC

[0084] 16 can be crimped onto the wire. Such marker sleeves, for example, have a higher radiopaque density compared to marker coils, resulting in improved radiographic visibility. Crimping the marker sleeves onto the wires creates a stable connection between the marker sleeves and the wires.

[0085] Furthermore, the supporting structure can have an antithrombogenic coating, which in particular comprises heparin and / or fibrin. In other words, the supporting structure can be coated with a material that has antithrombogenic properties. The coating can exert an anticoagulant effect, thus favorably influencing the adhesion of blood proteins. A layer of cells, especially endothelial cells, can then form over the supporting structure. The material of the supporting structure is thus masked by a layer of blood proteins, which also prevents or reduces the deposition of platelets and coagulation proteins, such as fibrinogen, which are primarily responsible for thrombus formation. Overall, this results in a reduction of the tendency to form thrombi. The antithrombogenic coating preferably comprises heparin and / or fibrin, with heparin being covalently bound to fibrin.

[0086] In a preferred embodiment, the proximal and distal sections have an angle between 20° and 110° to each other when unloaded. This allows the implant to adapt optimally to the course of the vessel, particularly in the region of a bifurcation aneurysm.

[0087] The implant preferably has at least one curvature along its longitudinal axis. The position of the at least one curvature along the longitudinal axis of the implant can be adapted to the application. It is conceivable that the transition section is bent or curved in the resting state or when unloaded, while the proximal and / or distal section runs essentially straight along its longitudinal axis. Alternatively, the proximal and / or distal section can include a curvature, while the transition section is essentially straight along its longitudinal axis. It is also possible that the implant or the supporting body has multiple curvatures or angled sections along its longitudinal axis. M / CAN-425-PC

[0088] 17

[0089] It is possible for the implant to have at least a first and a second region, wherein the first and second regions, in the unloaded state, form an angle between 20° and 110° to each other. Alternatively, the first and second regions can form an angle between 30° and 100°, in particular between 40° and 90°, in particular between 50° and 80°, and in particular between 60° and 70° to each other. The first region can, for example, be the proximal longitudinal end and the second region the distal longitudinal end of the implant.

[0090] According to the invention, the implant has at least the proximal and the distal sections, which are connected to each other by the transition section. Thus, the implant preferably has at least three sections along its longitudinal axis. It is possible for the implant to have a larger number of sections along its longitudinal axis. For example, the implant can have four, five, six, seven, eight, nine or more sections along its longitudinal axis.

[0091] If the implant has more than three sections, it is preferred that two sections with a substantially constant porosity are connected by a transition section with a porosity that changes in the axial direction. This is preferably understood to mean that at least one transition section with a porosity that changes in the axial direction is arranged between two sections with a substantially constant porosity.

[0092] Advantageously, each section of the implant is individually customizable. Thus, each section of the implant can have different dimensions, i.e., a different length in the axial direction and / or a different cross-sectional diameter. This allows the implant to be optimally adapted to a patient's vascular anatomy. Each section of the implant preferably has a length between 3 mm and 25 mm in the axial direction. Furthermore, each section preferably has a cross-sectional diameter between 2.5 mm and 8 mm. M / CAN-425-PC

[0093] 18

[0094] Furthermore, by changing the cross-sectional diameter along the longitudinal axis of the implant, it is possible to create a bulge in the support body. This bulge is preferably located on the section of the implant that covers the aneurysm when implanted. For example, the distal section can include a bulge. Such stents, which feature a bulge, are commonly referred to as barrel stents.

[0095] Barrel stents are particularly suitable for treating bifurcation aneurysms. The barrel stent's bulge is preferably positioned within the bifurcation. This bulge allows for improved wall adaptation in the bifurcation area. Barrel stents therefore provide good coverage of bifurcation aneurysms.

[0096] Alternatively or additionally, each section of the implant can have a different braiding angle. This allows the porosity of each section to be individually adjusted. In this way, good coverage of the lesion can be achieved in some sections, while other sections remain permeable to blood. Furthermore, this improves the openness retention and thus the wall adaptation in the different sections of the implant.

[0097] Furthermore, it is conceivable that each section of the implant has a different number of wires. This allows the porosity of each section to be individually adjusted. Additionally, this can result in the individual sections of the implant being radiopaque to varying degrees. A higher number of wires advantageously leads to improved radiolucency. In this way, it is possible to distinguish the individual sections of the implant from one another under X-ray. For example, the transition between the sections of the implant is visible under X-ray guidance. This enables the surgeon to ideally position the implant in the area of ​​the lesion.

[0098] Advantageously, the mesh size of the individual sections of the implant can be individually adjusted. Those sections that cover an outgoing vessel in the implanted state preferably have a mesh size between M / CAN-425-PC.

[0099] 19

[0100] 0.2 mm and 1 mm, in particular at least 0.4 mm, in particular at least 0.6 mm, in particular at least 0.8 mm. This advantageously ensures that the outgoing vessel is accessible through the mesh with a treatment device, for example a 2 French catheter.

[0101] Preferably, the radial force or bending stiffness of the individual sections of the implant can be adjusted such that, in the implanted state, a change, particularly a straightening, of the vessel course can be achieved. By straightening the vessel course, especially in the region of the aneurysm, the angle at which the blood strikes the aneurysm neck during use can be altered, particularly flattened, in such a way that the deflection of blood flow away from the aneurysm is improved. Adjusting the radial force or bending stiffness can be achieved, for example, by modifying the number of wires, the braiding angle, and / or the wire diameter in the individual sections of the implant.

[0102] The invention is explained in more detail with reference to an exemplary embodiment in conjunction with the schematic drawing.

[0103] This shows

[0104] Fig. 1 shows an embodiment of a medical implant according to the invention in the implanted state in the area of ​​a bifurcation of a vessel, wherein the implant is shown in a schematic representation;

[0105] Fig. 2 shows the medical implant according to Fig. 1 in the unloaded (fully expanded) state; and

[0106] Fig. 3 shows an enlarged section of the medical implant according to Fig. 1, where single wires are combined to form double wires.

[0107] The same reference numbers are used below for identical or equivalent parts. M / CAN-425-PC

[0108] 20

[0109] Figures 1 and 2 show an embodiment of a medical implant 10 according to the invention, in particular a stent 10, for treating a local lesion 100 in a bifurcation of a vessel. This involves the application of the implant 10 or the stent 10 for the treatment of a bifurcation aneurysm 100. Other applications are conceivable. For example, the implant 10 or the stent 10 is generally suitable for treating vascular lesions 100.

[0110] Fig. 1 shows the implant 10 in its implanted state in the region of a bifurcation. Fig. 2 shows the implant 10 in its unloaded state.

[0111] The implant 10 has a support body 11 that is compressible and expandable. Specifically, the support body 11 is self-expanding. The support body 11 is at least partially tubular in shape.

[0112] The support body 11 has a proximal section 12. The proximal section 12 is tubular or cylindrical in shape. The proximal section 12 is detachably connected to a transport wire (not shown) for the purpose of introducing the implant 10 into a vessel.

[0113] Furthermore, the support body 11 has a distal section 13. The distal section 13 is tubular or cylindrical in shape. When the implant 10 is inserted via a catheter, the distal section 13 is the first part to exit the implant (not shown).

[0114] The proximal section 12 exhibits a first porosity 12a, and the distal section 13 exhibits a second porosity 13a. The second porosity 13a is smaller than the first porosity 12a. The proximal section 12 is more porous than the distal section 13.

[0115] The second porosity 13a is sufficiently blood-tight to reduce blood flow into a lesion 100, and the first porosity 12a is sufficiently blood-permeable to maintain blood flow into an outgoing vessel 101b. M / CAN-425-PC

[0116] 21

[0117] The first and second porosities 12a, 13a are each essentially constant along the longitudinal axes L of the proximal and distal sections 12, 13. The proximal and distal sections 12, 13 exhibit essentially the same porosity 12a, 13a at every position along their longitudinal axes. Essentially constant or uniform porosity can also include a change in porosity that is so slight that the functions of the respective sections 12, 13—i.e., diverting blood flow from a lesion 100 by the distal section 13 and maintaining blood flow into an outgoing vessel 101b by the proximal section 12—are fulfilled. Specifically, it can be seen in Fig. 2 that the proximal section 13 has a porosity 13a that changes, particularly slightly, in the axial direction.

[0118] Figure 1 shows that the implant 10 is positioned in a bifurcation. The distal section 13 is positioned in a tributary vessel 101a of the bifurcation such that the aneurysm 100 is covered and the blood flow into the aneurysm 100 is reduced through the second porosity 13a. The proximal section 12 is positioned in the main vessel 102 of the bifurcation such that it spans another tributary vessel 101b, while maintaining blood flow into the tributary vessel 101b through the first porosity 12a.

[0119] The proximal and distal sections 12, 13 are connected by a transition section 14. The distal longitudinal end of the transition section 14 is connected to the distal section 13, and the proximal longitudinal end of the transition section 14 is connected to the proximal section 12. The transition section 14 is located between the proximal and distal sections 12, 13.

[0120] Fig. 2 shows that the transition section 14 exhibits a porosity that changes in the axial direction. The porosity of the transition section 14 is variable. The porosity of the transition section 14 increases in the proximal direction and decreases in the distal direction.

[0121] The first and second porosities 12a, 13a merge into each other in the transition section 14. The transition section 14 exhibits at its proximal longitudinal end the porosity of the proximal section 12, i.e., the first porosity 12a M / CAN-425-PC

[0122] 22 and at its distal longitudinal end the porosity of the distal section 13, i.e., the second porosity 13a. The porosity changes between the proximal and distal longitudinal ends of the transition section 14.

[0123] Fig. 1 shows that the transition section 14 is positioned in the vessel such that both the diversion of blood flow from the lesion 100 and the maintenance of blood flow into the collateral vessel 101b are achieved. For this purpose, the transition section 14 is arranged between the lesion 100 and the collateral vessel 101b.

[0124] The variable porosity of the transition section 14 allows the implant 10 and / or the support body 11 to be retracted into a catheter (not shown). The transition between the first and second porosities 12a, 13a is designed to prevent the support body 11 from bulging when retracted into a catheter in the area of ​​the transition section 14. This allows the implant 10 to be positioned precisely, so that the first porosity 12a ensures blood flow into an outgoing vessel 101b, the second porosity 13a reduces blood flow into the lesion 100, and the transition section 14 can be positioned between the lesion 100 and the outgoing vessel 101b.

[0125] Fig. 2 shows that the first and second porosities 12a, 13a in the transition section 14 merge essentially continuously into one another in the axial direction. The porosity of the transition section 14 increases essentially continuously in the proximal direction and decreases essentially continuously in the distal direction. This continuous transition results in improved retractability of the implant 10 into a catheter.

[0126] In the embodiment shown in Fig. 2, the support body 11 has a braided structure 15 that forms meshes 16. The support body 11, or rather the braided structure 15, is produced by braiding wires 17a, 17b. The support body 11 is formed from, or consists of, wires 17a, 17b. The wires 17a, 17b are braided helically. The wires 17a, 17b form meshes 16. M / CAN-425-PC

[0127] 23

[0128] The size of the meshes 16 defines the porosity of the supporting body 11 or the mesh structure 15. The larger the meshes 16, the higher the porosity. Fig. 2 shows that the mesh size of the proximal section 12 is larger than the mesh size of the distal section 13.

[0129] It can be seen that the transition section 14 has a mesh size that changes in the axial direction. In the transition section 14, the mesh size of the proximal section 12 preferably approaches the mesh size of the distal section 13, or vice versa.

[0130] The transition section 14 has an axial length of 6 meshes 16. A different number of meshes 16 is possible. For example, the transition section 14 can have an axial length of 2, 3, 4, or 5 meshes 16.

[0131] Furthermore, the transition section 14 has an axial length between 1 mm and 12 mm. Other lengths of the transition section 14 are possible.

[0132] The ratio of the mesh size of the proximal section 12 to the mesh size of the distal section 13 is between 1.5 and 10. This ratio allows both the diversion of blood flow from the lesion 100 and the maintenance of blood flow into an outgoing vessel 101b.

[0133] The first porosity 12a is between 3% and 30% larger than the second porosity 13a. This makes the first porosity 12a sufficiently permeable to blood to maintain blood flow into an outgoing vessel 101b.

[0134] Figure 2 shows that the transition section 14 is tubular or cylindrical in shape. The transition section 14 has a constant diameter along its longitudinal axis L. Alternatively, the transition section 14 can be conical.

[0135] Furthermore, the proximal section 12 may have a different, particularly larger, cross-sectional diameter than the distal section 13 (not shown). M / CAN-425-PC

[0136] 24

[0137] This is the case when the transition section 14 is cone-shaped.

[0138] Fig. 2 illustrates that the support body 11, or the mesh structure 15, is formed from wire strands 17. The wire strands 17 of the distal section 13 are each formed from a single wire 17a. The wire strands 17 of the proximal section 12 and the transition section 14 are formed from two wires 17a, 17b, which are bundled together or combined to form a double wire. It can be seen that the transition section 14 and the proximal section 12, which both comprise double wires, have a greater porosity than the distal section 13, which comprises single wires 17a.

[0139] The bundling of individual wires 17a into multiple wires is called bundling and is shown schematically in Fig. 3. Specifically, in Fig. 3, individual wires 17a are bundled into double wires at a specific position along the longitudinal axis L of the support body 11. This occurs at the boundary between the distal section 13 and the transition section 14. Alternatively, the bundling of wires 17a, 17b can occur at the boundary between the transition section 14 and the proximal section 12.

[0140] By combining wires 17a and 17b, a change in porosity is achieved. The porosity in the proximal section 12 and in the transition section 14 is greater due to the combined wires 17a and 17b than the porosity in the distal section 13, which is formed from individual wires 17a.

[0141] It can be seen that the wires 17a, 17b have a braiding angle relative to the longitudinal axis L of the support body 11. Furthermore, Fig. 2 shows that the wires 17a, 17b in the proximal section 12 have a smaller braiding angle than the wires 17a in the distal section 13. The wires 17a, 17b in the distal and proximal sections 12, 13 are one and the same wires 17a, 17b. That is, the wires 17a, 17b are oriented in the transition region 14 such that they have different braiding angles in the distal and proximal sections 12, 13.

[0142] Specifically, wires 17a and 17b in the proximal section 12 have a braiding angle between 45° and 60°. Wires 17a in the distal section 13 have a braiding angle between 60° and 80°. M / CAN-425-PC

[0143] 25

[0144] Fig. 2 further shows that the braiding angles of the proximal and distal sections 12, 13 merge into one another in the axial direction in the transition section 14. This results, among other things, in the continuous change in porosity in the transition section 14.

[0145] The braiding angle is a parameter used to change the porosity. In addition to the braiding angle, the wire diameter, the diameter of the support body 11, the number of wires 17a, 17b and / or the number of wires 17a 17b are used to change the porosity.

[0146] The wires 17a, 17b form closed loops 18 at a proximal longitudinal end 12b of the support body 11. This results in an increased erecting force at the proximal longitudinal end 12b, thereby ensuring secure anchoring of the proximal section 12 in the vessel.

[0147] The wires 17a form open wire ends 19 at a distal longitudinal end 13b of the support body 11.

[0148] Wires 17a and 17b are formed from a radiopaque core material and a shape-memory material. The core material comprises between 10% and 50% of the cross-sectional area of ​​wires 17a and 17b.

[0149] The core material is platinum or a platinum alloy. The shape memory material is nitinol. Other materials are possible.

[0150] The core material makes the wires 17a and 17b clearly visible under X-ray control. The shape-memory material allows the braided structure 15 to self-expand.

[0151] The support body 11 may additionally have at least one radiopaque marker (not shown) at the transition from the proximal section 12 to the transition section 14 and / or at the transition from the distal section 13 to the transition section 14. This may improve radiographic visibility.

[0152] The support body 11 has an antithrombogenic coating. The coating comprises heparin and / or fibrin. This reduces the risk of thrombus formation. M / CAN-425-PC

[0153] List of symbols Implant Supporting body Proximal section a First porosity b Proximal longitudinal end Distal section a Second porosity b Distal longitudinal end Transition section Mesh structure Meshes Wire strands a, 17b Wires Closed loops Open wire ends 0 Lesion, aneurysm 1a, 101b Branch vessel, offshoot vessel 2 Main vessel

Claims

M / CAN-425-PC 27 Claims 1. Medical implant (10) for treating a local lesion (100) in a vessel, in particular for treating a bifurcation aneurysm (100), comprising a support body (11) that is compressible and expandable, wherein the support body (11) comprises at least a proximal section (12) and a distal section (13) which are substantially tubular, in particular cylindrical, and are connected to each other by a transition section (14), wherein the proximal section (12) has a first porosity (12a) and the distal section (13) has a second porosity (13a) which is smaller than the first porosity (12a), characterized by the fact that the transition section (14) has a porosity that changes in the axial direction, wherein the first and second porosities (12a, 13a) merge into each other in the transition section (14), and wherein the transition section (14) can be positioned in the vessel in such a way,that the blood flow through the second porosity (13a) from the lesion (100) can be at least partially deflected and the blood flow into an outgoing vessel (101) through the first porosity (12a) can be at least largely maintained.

2. Medical implant (10) according to claim 1, characterized by the fact that the first and second porosities (12a, 13a) in the transition section (14) merge substantially continuously into each other in the axial direction.

3. Medical implant (10) according to claim 1 or 2, characterized by the fact that the support body (11) has a mesh structure (15) forming meshes (16), wherein the transition section (14) has a mesh size that changes in the axial direction.

4. Medical implant (10) according to one of the preceding claims, characterized by the fact that the transition section (14) has a length of in the axial direction of M / CAN-425-PC 28 has at least 2 stitches (16), in particular at least 3 stitches, in particular at least 4 stitches.

5. Medical implant (10) according to one of the preceding claims, characterized by the fact that the transition section (14) has a length in the axial direction between 1 mm and 12 mm, in particular at least 3 mm, in particular at least 5 mm, in particular at least 7 mm, in particular at least 9 mm, in particular at least 11 mm.

6. Medical implant (10) according to one of the preceding claims, characterized by the fact that the ratio of the mesh size of the proximal section (12) to the mesh size of the distal section (13) is between 1.5 and 10, in particular 2, in particular 3, in particular 4, in particular 5, in particular 6, in particular 7, in particular 8, in particular 9.

7. Medical implant (10) according to one of the preceding claims, characterized by the fact that the first porosity (12a) is between 3% and 30%, in particular at least 5%, in particular at least 10%, in particular at least 15%, in particular at least 20%, in particular at least 25%, larger than the second porosity (13a).

8. Medical implant (10) according to one of the preceding claims, characterized by the fact that the transition section (14) is tubular, in particular cylindrical, or conical.

9. Medical implant (10) according to one of the preceding claims, characterized by the fact that the proximal section (12) has a different, in particular larger, cross-sectional diameter than the distal section (13).

10. Medical implant (10) according to one of the preceding claims, characterized in that the mesh structure (15) is formed from wire strands (17), wherein the M / CAN-425-PC 29 Wire strands (17) of the distal section (13) are each formed from a wire (17a) and the wire strands (17) of the proximal section (12) and / or the transition section (14) are formed from at least two wires (17a, 17b) which are bundled together, in particular combined to form a double wire.

11. Medical implant (10) according to one of the preceding claims, characterized by the fact that the wires (17a, 17b) have a braiding angle with respect to the longitudinal axis (L) of the support body (11), wherein the wires (17a, 17b) in the proximal section (12) have a different, in particular smaller, braiding angle than the wires (17a) in the distal section (13).

12. Medical implant (10) according to one of the preceding claims, characterized by the fact that the wires (17a, 17b) in the proximal section (12) have a braiding angle between 45° and 60°, in particular 55°, and / or the wires (17a) in the distal section (13) have a braiding angle between 60° and 80°, in particular 75°.

13. Medical implant (10) according to one of the preceding claims, characterized by the fact that the braiding angles of the proximal and distal sections (12, 13) in the transition section (14) merge into each other in an axial direction, in particular substantially continuously.

14. Medical implant (10) according to one of the preceding claims, characterized by the fact that the wires (17a, 17b) form closed loops (18) at a proximal longitudinal end (12c) of the support body (11) and / or the wires (17a) form open wire ends (19) at a distal longitudinal end (13c) of the support body (11).

15. Medical implant (10) according to one of the preceding claims, characterized by the fact that the wires (17a, 17b) are made of a radiopaque core material, in particular platinum or a platinum alloy, and a shape memory material, in particular a nickel-titanium alloy, M / CAN-425-PC 30 are formed, wherein the core material has an area fraction between 10% and 50%, in particular between 20% and 30%, of the cross-sectional area of ​​the wire (17a, 17b).

16. Medical implant (10) according to one of the preceding claims, characterized by the fact that at least one radiographic marker is arranged at the transition from the proximal section (12) to the transition section (14) and / or at the transition from the distal section (13) to the transition section (14).

17. Medical implant (10) according to one of the preceding claims, characterized by the fact that the support body (11) has an antithrombogenic coating, which in particular comprises heparin and / or fibrin.

18. Medical implant (10) according to one of the preceding claims, characterized by the fact that the proximal section (12) and the distal section (11) have an angle between 20° and 110° to each other in the unloaded state.

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