Medical set for the treatment of aneurysms, manufacturing method and medical system for the treatment of aneurysms

Description

[0001] The invention relates to a medical set for the treatment of aneurysms according to the preamble of patent claim 1. Furthermore, the invention relates to a manufacturing method according to claim 11 and a medical system according to claim 12.

[0002] WO 2014 / 177634 A1 describes a highly flexible stent comprising a compressible and expandable lattice structure, wherein the lattice structure is formed as a single piece. The lattice structure comprises closed cells, each delimited by four lattice elements. The lattice structure has at least one cell ring comprising between three and six cells.

[0003] US 2018 / 0193026 A1 deals with a device for covering aneurysms with a mesh structure that can be transported to the treatment site via a catheter. The mesh structure is provided with a sheath that also covers the openings of the mesh structure, thus isolating the aneurysm from blood flow. The sheath limits the compressibility of the mesh structure and carries the risk of rupture if the mesh structure is subjected to severe deformation.

[0004] The applicant's practice also discloses stents with lattice structures made of a single wire. The wire is interwoven to form a tubular mesh. At the axial ends of the tubular mesh, the wire is deflected to form atraumatic loops. The axial ends can be flared in a funnel shape.

[0005] The known medical device is particularly suitable for the treatment of aneurysms in small cerebral blood vessels. Such blood vessels have a very small cross-sectional diameter and are often highly tortuous. The known stent is designed to be highly flexible, allowing it to be compressed to a very small cross-sectional diameter while also exhibiting high bending flexibility, allowing it to be delivered into small cerebral blood vessels.

[0006] To treat aneurysms in cerebral blood vessels, it is advisable to use stents that span the aneurysm and shield it from blood flow within the blood vessel. To achieve this, it is known to provide stents with a covering that seals off the stent cells, thus preventing blood flow into the aneurysm and perfusion of the blood vessel's side branches.

[0007] Another complementary or alternative treatment method for aneurysms is the implantation of so-called coils into the aneurysm, which causes blood to clot. The resulting thrombus then prevents blood circulation in the aneurysm and thus reduces the risk of rupture and subsequent bleeding.

[0008] However, especially in wide-necked aneurysms, the coils tend to migrate into the bloodstream during implantation, thus causing occlusion of the main vessel lumen. In the "balloon-assisted coiling" technique, catheters with "compliance balloons" are positioned within the vessel, specifically at the level of the aneurysm neck. The contrast-filled balloon closes the aneurysm neck during placement of the coils and forces the coils into a compact arrangement within the aneurysm space. Because coils are plastically deformable, they retain their shape. They do not leave the aneurysm even when the balloon is removed. However, this poses a problem, particularly due to the fact that the balloon occludes the vessel. If the procedure is prolonged (multiple coils are placed for large aneurysms, and the procedure can take several minutes), blood flow is completely interrupted.Although collateral vessels provide a supply to downstream tissue, the risk of underperfusion remains.

[0009] Furthermore, during the procedure, a catheter through which the coils are passed is "jailed," or clamped, to the side of the balloon. If it becomes necessary to replace the coil catheter (e.g., in case of damage) while the procedure is not yet complete, the balloon must be deflated to allow the catheter to be withdrawn. During this phase, the coils, which are not yet fully and compactly positioned within the vessel, may shift. This can then lead to vessel occlusion.

[0010] Against this background, the object of the invention is to provide a medical kit for the treatment of aneurysms, with the aid of which the risk of occlusion of side branches of a blood vessel is at least reduced. A further object of the invention is to provide a manufacturing method for a medical kit and a medical system.

[0011] According to the invention, this object is achieved with regard to the medical set by the subject matter of patent claim 1, with regard to the method for producing a medical set by the subject matter of patent claim 11 and with regard to the medical system by the subject matter of patent claim 12.

[0012] Preferred embodiments, further developments and variants are the subject of the subclaims.

[0013] Specifically, the problem is solved by a medical set for treating aneurysms, comprising a main catheter and a covering device that can be moved through the main catheter to a treatment site. The treatment site can be understood as a location along a vessel where the aneurysm is formed. The covering device serves to cover the aneurysm. Furthermore, the covering can be a temporary covering of the aneurysm, for example, only for the duration of the placement of an embolization agent within the aneurysm. Particularly preferably, the covering is permanent, i.e., a permanent covering, for example, in the form of a permanent implantation of the covering device in the vessel, specifically in the form of a stent or a flow diverter.

[0014] The covering device can be permanently mechanically connected to a transport wire, i.e., permanently. If the covering device forms a permanent implant, for example, a stent or a flow diverter, the connection to the transport wire can also be mechanically detachable. Furthermore, the covering device has a self-expanding lattice structure made of webs. Self-expanding here means that the lattice structure can transition from a compressed state to an expanded state without the influence of external forces. For this purpose, the lattice structure preferably has a shape-memory material or is formed from such a material.

[0015] The webs of the lattice structure are integrally connected to one another and delimit the inner cells and the edge cells. The edge cells form a closed edge cell ring at one longitudinal end of the lattice structure, for example, at a distal and / or proximal longitudinal end of the lattice structure. The edge cell ring is connected to the inner cells only on one side. The edge cell ring can be understood as a ring of circumferentially adjacent cells, in particular edge cells.

[0016] Furthermore, the lattice structure is provided with a covering made of a fabric. The fabric has irregularly sized pores. At least one inner cell of the lattice structure is at least partially and in particular largely free of covering, i.e., it is not provided with the covering or with part of the covering. Largely free of covering can be understood here as meaning that a continuous area, in particular of more than half the total area of ​​the lattice structure, is free of covering.

[0017] The advantage of this is that, on the one hand, the longitudinal axial permeability of the lattice structure ensures blood flow in the vessel, for example, during coil placement. On the other hand, reliable and site-specific coverage of the aneurysm is ensured without obstructing side branches. Another advantage is the reduction in the overall surface area of ​​the cover.

[0018] Because of the longitudinally axially permeable lattice structure, blood flow, particularly in the longitudinal direction through the blood vessel, is barely impeded, but the cover prevents blood from flowing into a branching aneurysm, or at least reduces the influence of flow into the aneurysm. This longitudinally axial permeability of the cover device has proven particularly suitable, particularly for permanent implantation of the cover device. A possible and undesirable occlusion of the vessel, as can occur, for example, with the balloon technique mentioned above, is thus at least reduced and preferably excluded. The at least one inner cell, which is cover-free, still enables the supply of the underlying vascular tissue.

[0019] Such a lattice structure design also enables the medical set to be used as a stent or flow diverter, which barely impedes blood flow longitudinally through the blood vessel and also, for example, to side vessels, but prevents blood from flowing into a branching aneurysm through the cover or at least reduces the flow influence. A possible and undesirable occlusion of the vessel, as can occur, for example, with the balloon technique mentioned above, is thus at least reduced and preferably eliminated. Furthermore, side vessels located next to or in the immediate vicinity of the aneurysm, for example, continue to be permeable to blood.

[0020] Particularly in the case of fusiform aneurysms, i.e., aneurysms that extend across the entire circumference of a blood vessel, it is advantageous to use a targeted, fine-pored structure for the colonization of endothelial cells. This can achieve reconstruction of the missing vessel wall. Specifically, the structure with a specific pore size, formed by the electrospun fabric, forms a scaffold for the colonization of endothelial cells, which can then form a new, closed vessel wall. Fusiform aneurysms are defined as aneurysms that extend across at least 50%, in particular at least 75%, of the entire circumference of a blood vessel, or across the entire circumference.

[0021] In a preferred embodiment, the cover is formed from an electrospun fabric.

[0022] In electrospun fabrics, pores are typically irregularly shaped. The manufacturing process certainly doesn't allow for a patterned arrangement or design of pores. However, the pore sizes can be adjusted using the process parameters to ensure that at least some of the pores have a certain minimum size.

[0023] For example, the electrospinning process can be performed directly on the grid structure, so that a bond to the grid structure is created simultaneously during the formation of the cover. The cover can be bonded to the grid structure by a material bond. For example, the cover can be bonded to the grid structure by an adhesive bond. The adhesive bond can be created using an adhesion promoter. The adhesion promoter can, for example, comprise or consist of polyurethane.

[0024] The cover, made of electrospun fabric, is also extremely thin and flexible, which supports the flexibility of the lattice structure. In particular, unlike previously known covers made of textile materials, the cover barely prevents the lattice structure from compressing. Overall, the entire cover device can be compressed to a significantly smaller cross-sectional diameter and thus guided into particularly small blood vessels via small catheters. This is particularly relevant for the treatment of aneurysms in cerebral blood vessels, for which the invention is particularly suitable.

[0025] The cover is preferably made of a plastic material, in particular a polymer, and preferably polyurethane. Such materials are particularly lightweight and can be easily produced in fine threads using an electrospinning process. The plastic material thus enables the production of a particularly thin and fine-pored cover. On the other hand, the plastic material inherently exhibits a high degree of flexibility, thus achieving a high compressibility of the medical set. Alternatively, the cover can also be made of polyethylene and / or fluoropolymers.

[0026] The medical set according to the invention therefore also enables treatments in blood vessels that cannot be achieved with previous medical devices featuring a grid structure and a cover. Due to the high compressibility of the device according to the invention, very low delivery forces occur during delivery through a catheter. The material of the cover can also contribute to reducing the delivery forces.

[0027] In particular, the feeding forces for the device with cover can be the same or smaller than for feeding the grid structure alone.

[0028] Furthermore, the covering device, which is conveniently positioned at the treatment site, i.e., at the level of the aneurysm, can prevent the coil from migrating out of the aneurysm during and after coil placement, so that the risk of vascular occlusion caused by the coils can also be at least significantly reduced and preferably eliminated. Especially when the covering device is designed as a flow diverter, i.e., as a permanent implant, insertion of the coils into the aneurysm can be dispensed with, since the covering preferably covers the aneurysm permanently, particularly fluid-dynamically.

[0029] Another area of ​​application for a partially covered device is fistulae, dissections, and other malformations, such as arteriovenous malformations, where flow needs to be slowed or prevented at specific locations, or vessel wall reconstruction is promoted by a fine-mesh structure to promote cell proliferation. In the open areas or open cells, blood flow should be unimpeded to ensure normal perfusion of side branches. Furthermore, foreign material is reduced to a minimum to improve biocompatibility and reduce potential thrombogenicity.

[0030] In order to ensure sufficient flexibility of the cover, it is preferably formed from irregularly arranged net-like threads which have a thread thickness between 0.1 µm and 3 µm, in particular between 0.2 µm and 2 µm, in particular between 0.5 µm and 1.5 µm, in particular between 0.8 µm and 1.2 µm.

[0031] It is particularly preferred if the medical set is designed in the manner of a stent for the treatment of aneurysms in arterial, particularly neurovascular, blood vessels. The blood vessels can preferably have a cross-sectional diameter between 1.5 mm and 5 mm, in particular between 2 mm and 3 mm. The treatment of blood vessels with a cross-sectional diameter of 4 mm to 8 mm is also possible. Carotid arteries, for example, have such cross-sectional diameters.

[0032] In a further embodiment, all webs of the inner cell are each assigned to another inner cell or edge cell. Furthermore, the edge cells each have at least two webs that are not assigned to another inner cell or edge cell. Thus, in this embodiment, the webs form both a boundary for an inner cell and a boundary for its adjacent edge cells.

[0033] The lattice structure can basically be designed as a one-piece lattice structure. The wire mesh of the lattice structure can consist of a single wire that is deflected and returned at the longitudinal ends of the mesh structure. The wire can be intertwined with itself to form the mesh structure. The mesh structure can also consist of multiple wires that are intertwined. The multiple wires can be deflected and returned at one axial longitudinal end, while the opposite axial longitudinal end can have open wire ends. It is also possible for the interwoven wires to have open wire ends at both axial longitudinal ends. The wire can comprise an X-ray visible core material and a cladding material made of a shape memory alloy.In particular, it is provided that the volume ratio between the core material, preferably platinum, and the volume of the entire composite wire is between 20% and 40%, in particular between 25% and 35%. While a braided lattice structure is characterized by particularly high flexibility, in particular bending flexibility, a one-piece lattice structure has a comparatively thin wall thickness, so that the lattice structure has less influence on blood flow within a blood vessel. The lattice structure can also be laser-cut. Furthermore, the lattice structure can be designed as a closed structure for retraction into a catheter, with between preferably 6 and 12 cells along the circumference of the lattice structure. The cells can have an asymmetric shape, i.e. the cells are essentially diamond-shaped, i.e. kite-shaped, but can deviate from this shape due to varying web widths and lengths.However, the diamond or kite shape remains essentially recognizable even if there is a deviation.

[0034] The grid structure preferably has a cross-sectional diameter between 2.5 mm and 8 mm, in particular between 4.5 mm and 6 mm.

[0035] According to a preferred embodiment, the cover terminates at the webs of the cover-free inner cells in such a way that the cover does not protrude into the at least one inner cell. In other words, the cover thus terminates substantially flush with the webs, so that an edge of the cover preferably follows the contour of the webs.

[0036] This ensures that the edge cells are free from covering and, at the same time, that the edge of the cover rests on the web, a reliable attachment to the grid structure is ensured, for example by means of the adhesive connection already mentioned.

[0037] According to an alternative embodiment, the cover at least partially overlaps the webs of the cover-free inner cell such that the cover partially protrudes into the at least one cover-free inner cell. In other words, according to this alternative embodiment, the cover does not follow the contour of the webs but rather protrudes into the at least one inner cell over at least 20%, in particular over at least 30%, in particular over at least 40%, in particular over at least 50%, of the area of ​​the at least one inner cell.

[0038] In both design variants, however, the cover remains stable. Preferably, the cover is so long-lasting or stable that the mass of the cover is reduced by a maximum of 5%, in particular by a maximum of 3%, in particular by a maximum of 1%, upon contact with blood or a physiological replacement fluid, in particular with a sodium chloride solution or a Ringer's lactate solution, at a flow rate of, in particular, 100 ml to 400 ml per minute, over a period of at least four hours, in particular at least 30 days. This ensures that the coating's effectiveness persists for a sufficiently long period.

[0039] It is particularly preferred if the covering is so long-term stable or stable that the mass of the covering is completely retained upon contact with blood or a physiological replacement fluid, in particular with a sodium chloride solution or a Ringer's lactate solution, for a period of at least four hours, in particular at least 30 days. Such a period allows, for example, the medical device to be coated by a layer of endothelial cells, so that thrombus formation is naturally prevented. The antithrombogenic coating thus bridges the period until natural healing or encapsulation of the medical device in a neointima layer, in particular of endothelial cells, which forms around the mesh structure elements.

[0040] Using a physiological replacement fluid to test the long-term durability of the cover allows for an objective comparison. Furthermore, the use of a replacement fluid, which is preferably similar to human blood, allows for objective empirical values ​​to be obtained that provide information about the behavior of the cover in the implanted state when exposed to human blood flow. Therefore, a 0.9 percent sodium chloride solution or a Ringer's lactate solution are preferably used as replacement fluids. Such replacement fluids are isotonic and are well suited as indicators of the behavior of the cover in the implanted state.

[0041] According to one embodiment, several inner cells directly adjacent in the circumferential direction of the lattice structure, in particular all inner cells, of an inner cell ring are free of covering. This ensures that neighboring side vessels and / or cells along the vessel can continue to be supplied with blood and thus with nutrients, while the aneurysm is reliably covered by the covering. Furthermore, this enables an individual covering effect / function of lattice structures with regard to an arrangement pattern of aneurysms along the vessel, so that, for example, the inner cells are provided with the covering only at the treatment sites where an aneurysm is located, and the remaining inner cells of the inner cell ring are free of covering.

[0042] Alternatively or additionally, several inner cells directly adjacent in the longitudinal direction of the grid structure are cover-free. This advantageously optimizes the previously mentioned possibility of individual covering effect / function of the covering device.

[0043] According to one embodiment, the cover extends only partially, in particular to a maximum of 50%, in particular to a maximum of 40%, in particular to a maximum of 30%, in particular to a maximum of 20%, over the circumference of the lattice structure. The cover therefore preferably extends only over the treatment site, for example over an opening of the aneurysm. This further development ensures that the aneurysm is completely decoupled in fluid dynamics terms when the lattice structure is used as a flow diverter. On the other hand, it is ensured that cells and / or side vessels located at the level of the aneurysm can continue to be supplied with blood and thus with nutrients due to the lack of cover.

[0044] In one embodiment, the cover has at least 10 pores with a size of at least 15 µm² over an area of ​​100,000 µm². During the production of the cover, the minimum pore size can be adjusted, in particular by the duration of the electrospinning process. This combination of a certain minimum number of pores and a minimum pore size has proven particularly beneficial in practice for ensuring sufficient blood permeability of the cover while simultaneously maintaining a good covering effect.

[0045] A secondary aspect of the invention relates to a method for producing a medical kit, which is preferably the medical kit already described above. The method comprises the following steps.

[0046] First, the grid structure is prepared. Then, the covering is applied to all inner cells, specifically using an electrospinning process.

[0047] Subsequently, at least one inner cell is cut free using a cutting tool, with the cutting tool being guided along the webs of the inner cell to be cut free. This completely removes the covering from the inner cell.

[0048] The cutting tool can be a mechanical cutting tool, such as a scalpel. Preferably, the cutting tool is a laser cutting tool, so that the cover is removed along the webs using a laser beam, thus cutting free the inner cell. Alternatively, the cutting device can also be a device that ensures that the at least one inner cell is free of the cover by etching.

[0049] Furthermore, it can additionally be provided that the edges of the cover on the cover-free inner cells are reworked. This can preferably be done thermally, for example, using a soldering iron, by rough machining the edges in a first step at a first temperature and then fine machining the edges at a temperature lower than the first temperature.

[0050] A further subordinate aspect of the invention relates to a medical system with a medical set, which is in particular the medical set already described above, so that the medical set has a main catheter and a covering device which can be moved through the main catheter to a treatment site for covering an aneurysm.

[0051] The covering device is connected or connectable to a transport wire. Furthermore, the covering device has a self-expanding lattice structure comprising webs that are integrally connected to one another and delimit inner cells and edge cells. The edge cells form a closed edge cell ring along the circumference of the lattice structure at one longitudinal end of the lattice structure. The edge cell ring is connected to inner cells only on one side, i.e., on the side oriented toward the inner cells. Furthermore, the medical system has at least one embolization agent for placement in the aneurysm. The embolization agent is preferably formed by a plastically deformable wire, in particular by a coil or by a liquid. Such embodiments of the embolization agent have proven particularly suitable with regard to the treatment of aneurysms.

[0052] In the event that the covering device is detachably, i.e. reversibly, connected to the transport wire, the covering device particularly preferably serves as a flow diverter for permanent implantation at the treatment site within the blood vessel. The reversible arrangement of the covering device on the transport wire is realized, for example, by means of a detachable mechanical lock. Furthermore, in this embodiment, the covering device designed as a flow diverter has open longitudinal ends in the implanted and expanded state, i.e., is open at both ends. The covering device is thus essentially cylindrical, i.e., tubular, so that blood flow through the blood vessel is still possible. This enables placement of the embolization agent - if necessary - both during the implantation of the covering device and at a later time following the implantation of the covering device.

[0053] In one embodiment and preferably, the medical system further comprises an additional catheter for delivering the embolizing agent into the aneurysm, wherein the additional catheter is independent of the main catheter and / or movable relative to the main catheter.

[0054] The advantages and preferred embodiments listed with regard to the medical kit apply mutatis mutandis to the method and the medical kit, and vice versa. All dimensional specifications listed with regard to the medical kit and the medical system apply to an expanded state of the lattice structure, unless otherwise stated.

[0055] Embodiments of the invention are explained in more detail below with reference to the accompanying schematic drawings. These show, in partially simplified representations: Fig. 1 is a side view of an embodiment of the medical set according to the invention, Fig. 2 is a close-up of a preferred embodiment of a cover device of a medical set according to the invention according to a preferred embodiment, Fig. 3 is a scanning electron microscope image of a cover of a cover device of a medical set according to the invention according to a preferred embodiment, Fig. 4 is a side view of an embodiment of the medical system according to the invention, with a temporary implantation of the cover device at a treatment site and Fig. 5 is a side view of a preferred embodiment of the medical system according to the invention, with a permanent implantation of the cover device at a treatment site.

[0056] In the figures, parts with the same function are always shown with the same reference symbols.

[0057] The Fig. 1 The schematically illustrated medical set 2 is used to treat aneurysms 4 and is in Fig. 1 shown in a state arranged within a vessel 6.

[0058] The medical set 2 comprises a main catheter 8 and a covering device 12 movable through the main catheter 8 to a treatment site 10. The treatment site 10 is preferably the location along the vessel 6 where the aneurysm 4 is formed. The covering device 12 serves to temporarily or permanently cover the aneurysm 4, wherein the covering device 12 comprises a self-expanding lattice structure 14 made of webs 16 (cf. Fig. 2 ). The lattice structure 14 is preferably made of a shape memory material in view of its self-expandability.

[0059] Furthermore, the covering device 12 is permanently or detachably mechanically connected to a transport wire 15 that can be moved within the main catheter 8. By means of this transport wire 15, the grid structure 14 and thus the covering device 12 can be pushed and retracted through the main catheter 8 in a non-expanded state.

[0060] In the expanded state, the lattice structure 14 can be perfused by blood in a longitudinal axial direction, i.e. in and against a flow direction F.

[0061] The grid structure 14 is arranged in particular within the vessel 6 such that the cover 26 is placed at the same height as an opening 30 of the aneurysm 4, so that the latter is covered by the cover 26, while at the same time a blood flow through the vessel 6 is not stopped. The cover 26 is thus in the embodiment according to Fig. 1 essentially tubular, in particular in the form of a hollow cylinder.

[0062] The cover 26 is preferably porous with large pores 28 (cf. Fig. 3 ) and permeable to blood, so that a nutrient supply to the cells covered by the cover 26 is still ensured. Alternatively, the cover 26 can also be porous and impermeable to blood.

[0063] The cover 26 serves in this case, in particular when placing an embolization agent 36 (cf. Fig. 4 ) within the aneurysm 4, means that the embolizing agent 40 cannot escape from the aneurysm 4 after placement until the blood within the aneurysm 4 has clotted due to the embolizing agent 36 and the aneurysm 4 is thus reliably closed.

[0064] Particularly preferably, the cover 26 is formed as an electrospun cover 26.

[0065] As in Fig. 1 As can be clearly seen, X-ray markers 32 are also provided in the medical set 2 and especially in the grid structure 14. The X-ray markers 32 are preferably located at the cell tips of edge cells 20 (cf. Fig. 2 ) of the lattice structure 14. Specifically, the X-ray markers 56 can be formed as X-ray-visible sleeves, for example made of platinum or gold, which are crimped onto the cell tips of the edge cells 20.

[0066] In Fig. 2 A close-up of a preferred embodiment of the covering device 12 according to the invention is shown. The webs 16 are integrally, i.e. monolithically, connected to one another and delimit inner cells 18 and edge cells 20. Preferably, all cells, in particular inner cells 18 and edge cells 20, are each delimited by four webs, which together form a diamond shape. These cells, enclosed on all sides, are referred to as closed cells. The edge cells 20 form a closed edge cell ring 24 (three edge cells 20 of the edge cell ring 24 are shown circled) in the circumferential direction at a longitudinal end 22 of the lattice structure 14, which is connected to inner cells 18 on only one side.

[0067] Furthermore, the grid structure 14 is provided with the cover 26 made of a fabric which has irregularly sized pores 28 (cf. Fig. 3 ). At least one inner cell 18, in Fig. 1 (in the image plane at the right edge of the grid structure 14) three inner cells 18 are formed without any cover.

[0068] The design of the cover 26 is shown in the scanning electron microscope image according to Fig. 3 clearly visible. It can be seen that the cover 26 has several irregularly sized pores 28, each delimited by threads 34. The electrospinning process creates several threads 34 that are irregularly aligned with each other. This is how the pores 28 are formed. Fig. 3 also that the pores 28 have a comparatively small pore size, although some pores 28 are sufficiently large to ensure, for example, blood permeability. Specifically, Fig. 3 Four pores 28 are graphically highlighted, which have a size of more than 30 µm 2<. The density of pores 28 with a size of more than 30 µm 2< indicates that the cover has at least 10 such pores 28 over an area of ​​100,000 µm 2<.

[0069] In Fig. 3 It is also evident that the threads 34 of the cover 26 cross several times. A special feature of the electrospinning process, however, is that there are points on the cover 26 at which only, i.e., no more than two threads 34 cross each other. This shows that the cover 26 has a very thin wall thickness overall and is therefore highly flexible.

[0070] The high flexibility of the cover 26 in combination with the high flexibility of the grid structure 14 results in the provision of a covering device 12 that can be introduced into a (blood) vessel 6 through very small delivery catheters. In particular, delivery catheters can be used that have a size of 6 French, in particular no more than 5 French, in particular no more than 4 French, in particular no more than 3 French, in particular no more than 2 French. Specifically, the covering device according to the exemplary embodiments described here can be used with catheters that have an inner diameter of no more than 1.6 mm, in particular no more than 1.0 mm, in particular no more than 0.7 mm, in particular no more than 0.4 mm.

[0071] In particularly preferred variants, the layer thickness of the cover 26 is at most 10 µm, in particular at most 8 µm, in particular at most 6 µm, in particular at most 4 µm. At most 4, in particular at most 3, in particular at most 2, threads 34 intersect. Generally, crossing points are provided within the electrospun structure of the cover 26, at which only 2 threads 34 intersect. The lattice structure 10 preferably has a cross-sectional diameter between 2.5 mm and 8 mm, in particular between 4.5 mm and 6 mm.

[0072] Fig. 4 shows a schematically illustrated embodiment of a medical system according to the invention during a temporary implantation of the covering device (12) at a treatment site 10.

[0073] The medical system comprises the above-mentioned medical set 2 with the main catheter 8 and the covering device 12, which has the grid structure 14 and the cover 26. The design of the cover 26 corresponds to the above-mentioned embodiment according to Fig. 1 .

[0074] The medical system further comprises an embolization agent 36, which is formed, for example, by a plastically deformable wire 38 or a liquid. The embolization agent 36 is placed within the aneurysm 4 using an additional catheter 40, which is also part of the medical system.

[0075] To place the embolization agent 36, the additional catheter 40, according to the illustrated embodiment of the medical system, is arranged essentially parallel to, i.e., next to, the medical set 2 within the vessel 6. The additional catheter 40, and specifically a tip of the additional catheter 40, is then "pushed" between a vessel wall and the cover 26 into the aneurysm 4 in order to place the embolization agent 36 in the form of the plastically deformable wire 38 (also referred to as a "coil"). The cover 26 prevents the embolization agent 36 from escaping from the aneurysm 4 during and—in the case of permanent implantation—also subsequently, for example, due to blood flow.

[0076] In Fig. 5 a schematically illustrated embodiment of a medical system according to the invention is shown with a permanent implantation of the covering device (12) at a treatment site 10.

[0077] With regard to the structural features, the medical set and the covering device 12 essentially correspond to the one already described above in Fig. 4 described medical set. The cover device 12 is in Fig. 5 shown in a state already implanted and expanded in the vessel 6. This means that the covering device 12 has already been brought to the treatment site 10 by means of the transport wire 15 and detached there from the transport wire 15.

[0078] The covering device 12 according to Fig. 5 However, each has open longitudinal ends and is thus essentially cylindrical, i.e. tubular, in order not to influence blood flow through the vessel. The cover device 12 in the embodiment according to Fig. 5 thus serves as a flow diverter. Bezugszeichenliste

[0079] 2Medical set 4Aneurysm 6Vessel 8Main catheter 10Treatment site 12Cover device 14Lattice structure 15Transport wire 16Bridge 18Inner cell 20Random cell 22Longitudinal end 24Random cell ring 26Cover 28Pore 30Aneurysm opening 32X-ray marker 34Suture 36Embolization agent 38Wire 40Additional catheter Flow direction

Claims

1. A medical set (2) for treating aneurysms (4), with a main catheter (8), a covering device (12) movable through the main catheter (8) to a treatment site (10) in order to cover an aneurysm (4), wherein the covering device (12) is connected to connectable to a transport wire (15) and comprises a self-expandable mesh structure (14) formed by struts (16) which are connected to one another in one piece and delimit inner cells (18) and edge cells (20), wherein, at a longitudinal end (22) of the mesh structure (14), the edge cells (20) form a closed edge cell ring (24) which is connected to the inner cells (18) on only one side, characterized in that the mesh structure (14) is provided with a covering (26) formed from a fabric which has pores (28) of irregular sizes, wherein at least one inner cell (18) of the mesh structure (14) is at least partially, in particular mainly, free of the covering.

2. The medical set (2) as claimed in claim 1, characterized in that the covering (26) is formed from an electrospun fabric.

3. The medical set (2) as claimed in claim 1 or claim 2, characterized in that the covering device (12) can be reversibly connected to the transport wire (15) and, in the expanded state, is open at both ends and permeable to blood.

4. The medical set (2) as claimed in any of the preceding claims, characterized in that all of the struts (16) of the inner cells (18) are respectively associated with a further inner cell (18) or edge cell (20), and the edge cells (20) respectively have at least two struts (16) which are not associated with any other inner cells (18) or edge cells (20).

5. The medical set (2) as claimed in any of the preceding claims, characterized in that the covering (26) ends at the struts (16) of the inner cells (18) which are free of the covering in a manner such that the covering (26) does not protrude into the inner cell (18) which is free of the covering.

6. The medical set (2) as claimed in any one of claims 1 to 4, characterized in that the covering (26) at least partially overlaps the struts (16) of the inner cell (18) which is free of the covering, so that part of the covering (26) protrudes into the inner cell (18) which is free of the covering.

7. The medical set (2) as claimed in any of the preceding claims, characterized in that a plurality of inner cells (18) which are immediately adjacent in the circumferential direction of the mesh structure (14), in particular all of the inner cells (18) of an inner cell ring, are free of the covering.

8. The medical set (2) as claimed in any of the preceding claims, characterized in that a plurality of inner cells (18) which are immediately adjacent in the longitudinal direction of the mesh structure (14) are free of the covering.

9. The medical set (2) as claimed in any of the preceding claims, characterized in that the covering (26) extends only partially over the circumference of the mesh structure (14), in particular by at most 50%, in particular by at most 40%, in particular by at most 30%, in particular by at most 20%.

10. The medical set as claimed in any of the preceding claims, characterized in that the covering (26) comprises at least 10 pores (28) with a size of at least 15 µm2 over an area of 100000 µm2.

11. A method for manufacturing a medical set (2) as claimed in any of the preceding claims, wherein the method has the following steps: a. providing the mesh structure (14); b. applying the covering (26) to all of the inner cells (18) using an electrospinning process; c. cutting at least one inner cell (18) free by means of a cutting tool, wherein the cutting tool is guided along the struts (16) of the inner cells (18) to be cut free so that the inner cell (18) is at least partially, in particular mainly, free of the covering.

12. A medical system with a medical set (2) as claimed in any of claims 1 to 9 and with at least one embolization means (36) for placement in the aneurysm (4).

13. The medical system as claimed in claim 12, characterized in that the covering device (12) is detachably connectable to the transport wire (15) for a permanent implantation of the covering device (12) at the treatment site (10), wherein in the expanded state, the covering device (12) has open longitudinal ends (22).

14. The medical system as claimed in claim 12, characterized in that the covering device (12) is non-detachably connected to the transport wire (15) for a temporary implantation of the covering device (12) at the treatment site (10).

15. The medical system as claimed in one of claims 12 to 14, characterized in that in addition, an additional catheter (40) is provided for delivering the embolization means (36) into the aneurysm, wherein the additional catheter (40) is relatively movable with respect to the main catheter (8) independently of and / or in relation to the main catheter (8).