Medical device for treating vascular lesions

Abstract

The invention relates to a medical device (10) for treating vascular lesions, in particular aneurysms, the medical device comprising a compressible and expandable lattice structure (11) formed from struts (12) that define cells (13) of the lattice structure (11), wherein the lattice structure (11) is covered, at least in sections, by a membrane (14), in particular an electrospun membrane, wherein the lattice structure (11) has at least one first section (15) and at least one second section (16), wherein the first section (15) is arranged at an axial end (19) of the lattice structure (11) and extends in the axial direction over a length which is at most 15%, in particular at most 10%, of the length of the lattice structure (11), and wherein the first section (15) has open cells (17) and the second section (16) has closed cells (18), and the membrane (14) extends at least over the first and second sections (15, 16).

Description

[0001] Medical device for the treatment of vascular lesions

[0002] Description

[0003] The invention relates to a medical device for the treatment of vascular lesions, in particular aneurysms, with a compressible and expandable lattice structure made of webs that delimit cells of the lattice structure, wherein the lattice structure is covered at least in sections with a membrane, in particular an electrospun membrane.

[0004] The medical device mentioned above is known, for example, from DE 10 2018 131 269 A1, which originates from the applicant. This device enables the efficient treatment of vascular lesions. The device has a membrane designed to significantly reduce blood flow into the aneurysm, allowing the blood to clot within the aneurysm and form a thrombus.

[0005] Medical devices that incorporate a membrane often have the problem that, especially in sharply curved vessels, they do not always have sufficient flexibility to fit snugly against the vessel wall (wall adaptation). This creates the risk of blood flowing between the vessel wall and the device, and thus into the aneurysm (endoleak). As a result, the aneurysm is not adequately shielded from the bloodstream. Furthermore, there is a risk of vessel occlusion due to the medical device collapsing.

[0006] The invention is therefore based on the object of providing a medical device for the treatment of vascular lesions, in particular aneurysms, by means of which an efficient treatment of aneurysms is achieved even under difficult conditions, for example severe vascular curvatures.

[0007] According to the invention, the object is achieved with regard to the medical device by the subject matter of claim 1. Specifically, the object is achieved by a medical device for treating vascular lesions, in particular aneurysms, with a compressible and expandable lattice structure made of webs that delimit cells of the lattice structure, wherein the lattice structure is covered at least in sections with a membrane, in particular an electrospun membrane. The lattice structure has at least a first section and at least a second section, wherein the first section is arranged at an axial end of the lattice structure and has a length in the axial direction that amounts to at most 15%, in particular at most 10%, of the length of the lattice structure, and wherein the first section has open cells and the second section has closed cells, and the membrane extends at least over the first and second sections.

[0008] The invention has several advantages.

[0009] The medical device thus enables the efficient treatment of vascular lesions even under challenging conditions, such as severe vessel curvatures. For this purpose, the device features a membrane that covers at least sections of the lattice structure. The membrane is designed to significantly reduce blood flow into the vascular lesion or aneurysm, allowing the blood to coagulate within the aneurysm and form a thrombus. This naturally obliterates the aneurysm, ensuring that the thrombus cannot leave the aneurysm.

[0010] A further advantage of the invention is that the lattice structure which supports the membrane, on the one hand, has good wall adaptation and, on the other hand, enables the device to be retracted. For this purpose, the lattice structure has a hybrid design. The hybrid design is achieved in that the lattice structure has at least a first section and at least a second section whose cells are differently designed. The first section has open cells (open cell design) and the second section has closed cells (closed cell design). This combines the advantages of a closed-cell and an open-cell design in one device. The open-cell design in the first section, on the one hand, achieves very good wall adaptation, particularly in tortuous vessels. On the other hand, the closed-cell design in the second section enables the device to be retracted.

[0011] The good wall adaptation of the first section is achieved in that the first section is short or has a short length. For example, the invention provides that the first section has a length in the axial direction which is at most 15% of the length of the lattice structure. Particularly preferably, the length of the first section is at most 10% of the length of the lattice structure. The short length of the first section advantageously ensures that the first section can assume an almost circular cross-section in the expanded state, as a result of which the first section adapts particularly well to the vessel wall during use. This is particularly advantageous when the vessel has a steep curvature. The good wall adaptation of the first section can prevent the blood from getting between the device and the vessel wall and forcing the membrane off the vessel wall.This also prevents the lattice structure from buckling and thus occlusion of the vessel.

[0012] By arranging the first section at an axial end of the lattice structure, it is achieved that the end of the lattice structure has very good wall adaptation and rests against the vessel wall. The first section thus forms a short end region of the device that adheres optimally to the vessel wall and prevents blood from flowing between the device and the vessel wall. This ensures that the end of the lattice structure does not offer any area of ​​attack for the blood flow. The blood cannot therefore pass over the ends of the lattice structure between the device and the vessel wall. This prevents blood from flowing around the device and / or into the aneurysm (endoleak). This ensures efficient treatment of the aneurysm.

[0013] The closed-cell design of the second section is configured to achieve high supporting force and balanced load distribution of the radial force on the vessel wall. This ensures that the device is well anchored in the vessel. If the open-cell design is arranged on one side, i.e. in particular at the proximal end of the lattice structure, the closed-cell design of the second section also has the advantage of good retractability for repositioning the device in the vessel (resheathability). If, for example, the open-cell section has a length that is 10% of the length of the entire lattice structure, 90% of the lattice structure is retractable. This enables a surgeon to position the device and in particular the membrane precisely, so that the aneurysm can be treated efficiently. Furthermore, it can be ensured that branching vessels are not covered by the membrane.

[0014] The short length of the first section, which is arranged in particular at the proximal end of the lattice structure, achieves, on the one hand, good wall adaptation at the, in particular proximal, end of the lattice structure and, on the other hand, the retractability of the device. To achieve good wall adaptation at the, in particular proximal, end of the lattice structure, it is advantageously sufficient if the open-celled, first section has a length that amounts to a maximum of 15% of the length of the lattice structure. By limiting the open cells to the, in particular proximal, end of the lattice structure, which has a length of a maximum of 15% of the lattice structure, it is further ensured that the lattice structure is retractable.

[0015] The membrane is preferably arranged on the lattice structure in such a way that the formation of cavities (pocket formation) between the membrane and the vessel wall is avoided. This preferably means that the membrane does not sag between the webs of the lattice structure. In particular, the good wall adaptation of the first section can reduce the risk of such cavities forming. This ensures a good covering effect for the aneurysm.

[0016] The membrane extends over both the first and the second section of the lattice structure. The closed cells of the second section as well as the open cells of the first section are covered by the membrane. Since both sections are covered with the membrane, both sections can serve to cover the aneurysm. Particularly preferably, only the second section serves to cover the aneurysm. Since the first section is arranged at an axial end of the lattice structure, the membrane extends from one end of the lattice structure at least to the second section. The advantage here is that the first section of the lattice structure can serve to cover the aneurysm thanks to its good wall adaptation even in the case of severe vessel curvatures and / or is adapted so well to the vessel curvature that endoleaks can be avoided.

[0017] Particularly preferably, the membrane of the device according to the invention is produced by electrospinning, or the membrane is preferably formed from electrospun material. For the design of the membrane, reference is made to the applicant's patents DE 10 2018 131 269 B4 or DE 10 2019 135 502 B4.

[0018] The membrane advantageously allows a certain degree of permeability to blood. For this purpose, the membrane is preferably porous or has pores. This permeability is useful for supplying the cells of the aneurysm wall with nutrients. This prevents cell degeneration and a potentially resulting rupture of the aneurysm.

[0019] The medical device has a lattice structure, in particular a tubular wall made of a lattice structure. The lattice structure can be self-expanding or balloon-expandable.

[0020] The grid structure can be a mesh of braided wires or a single braided wire. The grid structure can also be a monolithic grid structure, for example, a laser-cut grid structure.

[0021] Preferred embodiments of the invention are claimed or specified in the subclaims.

[0022] In one embodiment, the first section is arranged at the proximal end of the lattice structure and / or forms a proximal end of the lattice structure. The proximal end of the lattice structure has open cells or an open-cell design. The arrangement of the open cells is advantageously limited to the proximal end of the lattice structure. The remaining lattice structure is preferably formed from closed cells. Since the proximal end of the lattice structure is the last to leave a delivery aid, for example a catheter, during delivery or positioning of the device, the open-cell design of the proximal end has virtually no influence on the repositionability of the device. If, for example, the first section has a length that is a maximum of 15% of the length of the entire lattice structure, the remaining 85% of the lattice structure is completely retractable.The device therefore advantageously exhibits good retractability for repositioning the device within the vessel (resheathability). This allows for optimal positioning of the device within the vessel.

[0023] The number of cells of the second section per circumferential segment is advantageously smaller than the number of cells of the first section per circumferential segment. The first and second sections can each have a plurality of circumferential segments with a plurality of cells that are connected to one another in the circumferential direction. In one embodiment of the invention, the first section has a larger number of cells per circumferential segment than the second section. By transitioning from a smaller number of cells in the second section to a larger number of cells in the first section, a flexible proximal region of the lattice structure can be provided, which leads to good wall adaptation. The flexible proximal region of the lattice structure and the large number of cells in the end region of the device advantageously lead to good adaptation of the proximal end of the lattice structure to the vessel wall and in particular to complex vessel geometries.This is particularly advantageous in cases of severe vessel curvature. Good wall adaptation can reduce the risk of endoleaks.

[0024] The second section can have at least two cells per circumferential segment and the first section can have at least six cells per circumferential segment. Particularly preferably, the second section has three cells per circumferential segment, wherein the cells can each be divided into two half-cells by a diagonal web. The first section preferably has nine cells per circumferential segment. It has been shown that in the case of severe vessel curvatures, a number of nine cells per circumferential segment in the first section of the device leads to particularly good adaptation to the vessel wall. Furthermore, the preferably three-cell design of the second section achieves a high supporting force or radial force with a balanced load distribution, while maintaining good flexibility of the lattice structure.

[0025] The cells of the first section are preferably shorter in the axial direction of the lattice structure than the cells of the second section. The cells of the first section are preferably shorter than the cells of the second section. Short cells or a short cell length can improve the wall adaptation of the lattice structure or of the first section. In general, the cells can be shorter as the number of cells per circumferential segment increases. For example, the preferably nine cells of the first section can be shorter than the preferably three cells of the second section. By having a high number of cells that have a short length in the axial direction, an approximately circular cross-section can be achieved in the expanded state of the lattice structure. This advantageously leads to good adaptation of the lattice structure to the vessel wall.

[0026] Preferably, the cells of the second section are substantially diamond-shaped and have a connecting web that extends into the cell and / or bridges it diagonally. The connecting web advantageously divides the cell into two sub-cells or partial cells, in particular into two half-cells, specifically two substantially symmetrical half-cells arranged between the webs and the connecting web. The main cell preferably has X-shaped web connectors at the diamond tips. Thus, four X-shaped web connectors can be provided per main cell. The connecting web can be connected by a flexible, in particular Z-shaped, web connector.

[0027] Regarding the cell design of the second section, reference is made to DE 10 2023 104 170 A1, which originates from the applicant, according to which the second section preferably has a compressible and expandable lattice structure made of webs which are connected to one another by web connectors and which delimit closed cells of the lattice structure, wherein two webs are arranged opposite at least one cell and form a first web pair and a second web pair, and wherein one of the two web pairs is connected to one another by at least one connecting web which extends into the cell and bridges it.

[0028] The cells of the first section can be substantially diamond-shaped. It is preferably provided that each cell of the first section is connected only to a circumferentially adjacent cell by an X-shaped web connector. The cell openings of those circumferentially adjacent cells that are not connected by an X-shaped web connector advantageously merge into one another, thereby forming a common free surface or cell opening. This achieves the open-cell design of the first section.

[0029] Particularly preferably, the first section has only one circumferential segment, i.e., only one cell row. This one circumferential segment preferably forms the proximal end segment of the lattice structure. It is conceivable for the first section to have multiple circumferential segments, for example, two or three circumferential segments. In any case, the length of all circumferential segments of the first section in the axial direction is at most 15%, in particular at most 10%, of the length of the lattice structure.

[0030] The first section or preferably one circumferential segment of the first section merges into the second section in a flexible transition region or forms a flexible transition region with the second section. The cells of the first section or of the one circumferential segment of the first section can partially form free ends (free diamond tips) in the distal direction, i.e. in the transition region. This is preferably to be understood in such a way that the cells of the first section are partially not connected to the cells of the second section in the transition region or in the distal direction. This is achieved in particular by the transition from a smaller number of cells in the second section to a larger number of cells in the first section. It is preferably provided that at least 3 / 4, in particular at least 2 / 3, in particular at least 1 / 2, of the cells of the first section form free ends (free diamond tips) in the distal direction.Conversely, it can be provided that at most 1 / 2, in particular at most 1 / 3, in particular at most 1 / 4, of the cells of the first section are connected distally to the cells of the second section. This creates large free spaces between the webs in the transition region, for example, compared to the second section. As a result, the transition region exhibits good flexibility, in particular bending flexibility. This improves wall adaptation.

[0031] By transitioning from a smaller number of cells in the second section to a larger number of cells in the first section, or through the transition area, a decoupling of the first section from the second section can be achieved. The decoupling of the first section from the second section is advantageously achieved through the flexible transition area. The good wall adaptation of the first section is thus almost unaffected by the remaining lattice structure.

[0032] The lattice structure may have at least a third section for anchoring the device in a vessel, which is substantially free of membrane. This is preferably understood to mean that the third section improves the anchoring of the device in the vessel. The remaining sections of the lattice structure, ie, the first and second sections, can themselves provide a certain degree of anchoring. The third section increases the security of the anchoring in the vessel or at the treatment site. The risk of migration is thereby significantly reduced.

[0033] Preferably, the third section is substantially free of membrane. This should preferably be understood to mean that the third section is largely not covered by the membrane. It is conceivable that the membrane extends at least partially into the proximal region of the third section. In use, the third section is preferably arranged distal to the vascular lesion and in this case does not serve to cover the vascular lesion. It is therefore expedient if the third section is substantially free of membrane. The membrane preferably extends only over the first and second sections. Alternatively, it is conceivable that the membrane extends at least partially or completely over or covers the third section of the lattice structure. The third section can serve, on the one hand, to cover the lesion and, on the other hand, to anchor the device in the vessel.

[0034] The third section can be arranged distal to the first section and / or form a distal end of the lattice structure. In this case, the distal end of the lattice structure serves to anchor the device in the vessel. The third section preferably has a lattice structure with closed cells. The cells of the third section can be essentially diamond-shaped. Preferably, six closed cells are provided per circumferential segment of the third section. A different number of cells per circumferential segment is possible. For example, three to twelve cells can be provided per circumferential segment of the third section. Due to the closed-cell design, the third section has good retractability for repositioning the device in the vessel. This is particularly advantageous since the distal end, i.e. the third section of the lattice structure, is the first to leave the catheter when the device is introduced or positioned.The third section is easily retractable thanks to the closed-cell design.

[0035] Due to the preferred arrangement of the third section at the distal end of the lattice structure and the second section at the proximal end of the lattice structure, the lattice structure advantageously has an asymmetric design. In this case, the distal end has closed cells and the proximal end has open cells, resulting in an asymmetrical lattice structure. The advantages of an open-cell and a closed-cell design can thus be combined in one device.

[0036] Preferably, the third section forms an enlarged diameter of the lattice structure with a flaring angle b. Such a radial widening of the distal end can, for example, avoid the risk of stent migration. Furthermore, the deliverability of the stent is improved due to lower radial forces in the flaring region. Preferably, the flaring angle b is between 5° and 20°. Particularly preferably, the flaring angle b is between 10° and 16°. It should be noted that a specific flaring angle is advantageous for a specific diameter range of the device. The invention is not limited to a specific diameter range of the device.

[0037] The flaring angle b is generally measured in the resting state, i.e., when no external forces act on the stent, between two opposing ribs of the expanded axial end. The flaring angle b can be understood as a conical or tapered opening angle.

[0038] In a further embodiment, the lattice structure has a plurality of X-ray visible marker elements, wherein the first section and the second section each have at least one marker element. As a result, the device has good X-ray visibility. The arrangement of the marker elements on the first and second section ensures that the area of ​​the lattice structure covered by the membrane is clearly visible under X-ray control. This makes it possible for a surgeon to assess the opening behavior of the device. It is conceivable for the first and second section to each have a plurality of marker elements, so that the entire area of ​​the lattice structure covered by the membrane is X-ray visible. The marker elements are preferably each arranged in a central region of the webs.

[0039] The marker elements can have a marker sleeve that is crimped onto the webs of the grid structure. The marker sleeves are preferably C-shaped and made of an X-ray-visible material, for example, a platinum-iridium alloy. The marker sleeves can be crimped over the webs of the grid structure and thus connected to them. The marker sleeves are preferably connected to the webs of the grid structure before the membrane is applied to the grid structure.

[0040] Alternatively, the marker elements can be formed as a coating that is firmly bonded to the webs of the grid structure. An X-ray-visible material can be applied to the surface of the webs. It is conceivable that web intersections or connectors and / or central regions of the webs could be coated. The coating is preferably applied to the webs of the grid structure before the membrane is applied to the grid structure.

[0041] It is possible for at least one X-ray-visible wire element, in particular a DFT wire, to be woven into the lattice structure and to extend at least over the first section and the second section. As a result, the region of the device covered by the membrane is advantageously clearly visible under X-ray control. In this way, the membrane can be correctly positioned at the treatment site. Furthermore, the opening behavior of the device can be easily assessed. One or more wires can be woven into the lattice structure. The membrane is preferably applied to the lattice structure after the at least one wire element has been woven in. Particularly preferably, the at least one wire element is designed as a DFT wire and has an X-ray-visible core material and a superelastic sheath material.

[0042] The invention will be explained in more detail below using exemplary embodiments with reference to the accompanying drawings.

[0043] Fig. 1 is a developed view of the lattice structure of an embodiment of the medical device according to the invention;

[0044] Fig. 2 shows an enlarged section of the lattice structure according to Fig. 1 in the region of the second section;

[0045] Fig. 3 shows the lattice structure of the medical device according to Fig. 1, wherein the lattice structure is partially covered with a membrane;

[0046] Fig. 4 shows an enlarged section of the lattice structure according to Fig. 1, wherein the lattice structure has X-ray visible marker elements;

[0047] Fig. 5 shows an enlarged section of the grid structure according to Fig. 1, wherein an X-ray visible wire element is woven into the grid structure;

[0048] Fig. 6 shows an enlarged section of the lattice structure according to Fig. 1, wherein the lattice structure has X-ray visible coatings;

[0049] Fig. 7 shows the lattice structure of the medical device according to Fig. 1 in the expanded rest state; and Fig. 8 shows the lattice structure of the medical device according to Fig. 1 in the expanded rest state, wherein the lattice structure has marker elements.

[0050] Fig. 3 shows an embodiment of a medical device 10 according to the invention for treating vascular lesions. This involves the application of the device 10 as a stent or, more generally, as a temporary or permanent vascular implant. Specifically, the device 10 is used to treat aneurysms. Other applications are conceivable. For example, the device 10 can be used to treat fistulas, dissections, or stenoses.

[0051] The device 10 has a compressible and expandable lattice structure 11 made of webs 12 that define cells 13 of the lattice structure 11. The lattice structure 11 is monolithic. The lattice structure 11 can be manufactured, for example, by laser cutting.

[0052] For clarity, the lattice structure 11 is shown in its expanded state in Figs. 1, 2, 4, 5, and 6. Figs. 3, 7, and 8 show the lattice structure 11 in its expanded, resting state, ie, when no external forces act on the lattice structure 11.

[0053] Fig. 3 shows that the lattice structure 11 is partially covered with a membrane 14. The membrane 14 is produced by electrospinning. The membrane 14 is formed from or consists of an electrospun material. For example, the membrane 14 is formed from perfluorinated or partially fluorinated polymers (e.g., PTFE, PVDF), polyolefin (e.g., PP, PE), polyurethane (e.g., thermoplastic polyurethane, hydrophilic polyurethane), polyamide (e.g., PA6.6), polyester (e.g., PLA, PLGA, PET), polysulfone (e.g., PSU), polyetheretherketone (PEEK), biological and / or protein-based polymers.

[0054] The lattice structure 11 has a hybrid design. It can be seen that the hybrid design is achieved by the lattice structure 11 having a first section 15 with open cells 18 (open cell design) and a second section 16 with closed cells 17 (see Figs. 1, 3, 7, and 8). The closed cells 17 of the second section 16 are designed to provide high support force for the lattice structure 11 and a balanced load distribution of the radial force on the vessel wall. The closed cells 17 also serve to provide good retractability to ensure repositioning of the device 10 in the vessel.

[0055] Figures 1, 3, 7, and 8 show that each open cell 18 of the first section 15 is connected only to a circumferentially adjacent cell 18 by an X-shaped web connector 30. The cell openings of those circumferentially adjacent cells 18 that are not connected by an X-shaped web connector 30 merge into one another and form a common free surface or cell opening. The open cells 18 of the first section 15 ensure good wall adaptation, particularly in highly curved vessels.

[0056] The first section 15 is arranged at an axial end 19 of the lattice structure 11 (see Figs. 1, 3, 7, and 8). The open-cell design is limited to one end of the lattice structure 19.

[0057] In the embodiment according to Figs. 1, 3, 7, and 8, the first section 15 has a circumferential segment 21 with nine open cells 18. The circumferential segment 21 with the nine open cells 18 forms the proximal end segment of the lattice structure 11.

[0058] One circumferential segment 21 of the first section 15 merges into the second section 16 in a transition region 22. The cells 18 of one circumferential segment 21 of the first section 15 partially form free ends (free diamond tips) in the distal direction, i.e. in the transition region 22, or are not connected to the cells 17 of the second section 16 in the axial direction. Specifically, the diamond tips of six of the nine cells 18 of the circumferential segment 21 form free diamond tips. The diamond tips of the remaining three of the nine cells 18 are connected in the axial direction to the diamond tips of the cells 17 of the second section 16. As a result, in the transition region 11, large free areas are formed between the webs 12 compared, for example, to the cells 18 of the second section 16. The transition region 22 therefore has good flexural flexibility, which leads to good wall adaptation.

[0059] 1, 3, 7, and 8 show that the first section 15 occupies a small portion of the total length of the device 10 or the lattice structure 11. Specifically, the first section 15 is intended to have a length that amounts to a maximum of 15% of the length of the lattice structure 11. The short length of the first section 15 ensures that the first section 15 adapts particularly well to the vessel wall during use and has good wall adaptation. The good wall adaptation of the first section 15 can prevent blood from entering the device 10 and the vessel wall from an axial end of the lattice structure 19 and forcing the membrane 14 off the vessel wall. This can prevent blood from flowing into the aneurysm (endoleak).

[0060] The first section 15 is shorter than the second section 16, or the first section 15 has a shorter length than the second section 16. The open-cell section 15 is shorter than the closed-cell section of the lattice structure 11.

[0061] Because the first, open-cell section 15 is short and limited to one axial end of the lattice structure 11, the device 10 is retractable. If the open-cell section 15 has a length that amounts to 15% of the length of the entire lattice structure 11, the remaining 85% of the lattice structure 11, which has closed cells 17, is retractable. This allows a surgeon to precisely position the device 10, and in particular the membrane 14, so that the aneurysm can be treated efficiently. Furthermore, it can be ensured that branching vessels are not covered by the membrane 14.

[0062] In the embodiment according to Fig. 3, it can be seen that the membrane 14 extends over the first and second sections 15, 16. The membrane 14 covers the closed cells 17 of the second section 16 and the open cells 18 of the first section 15. The first section 15 is arranged at the proximal end of the lattice structure 19 or forms a proximal end of the lattice structure 19. The open-cell design is limited to the proximal end of the lattice structure 19. In this way, the open cells 18 ensure good wall adaptation at the proximal end of the lattice structure 19 without significantly influencing the repositionability of the device 10.

[0063] The short length of the first section 15 ensures, on the one hand, good wall adaptation at the proximal end of the lattice structure 19 and, on the other hand, the retractability of the device 10. To achieve good wall adaptation at the proximal end of the lattice structure 19, it is sufficient if the open-cell, first section 15 has a length that amounts to a maximum of 15% of the length of the lattice structure 11. By limiting the open cells 18 to the proximal end of the lattice structure 19, which has a length of a maximum of 15% of the lattice structure 11, it is further ensured that the lattice structure 11 is retractable.

[0064] As can be seen in Figs. 1, 3, 7, and 8, the number of cells 17 of the second section 16 per circumferential segment 20 is smaller than the number of cells 18 of the first section 15 per circumferential segment 21. The first section 15 has more cells 18 per circumferential segment 21 than the second section 16. The comparatively high number of cells in the first section 15 results in the first section 15 having an approximately circular cross-section in the expanded state. As a result, the first section 15 exhibits good conformability to the vessel wall and good wall adaptation.

[0065] The transition region 22 is formed by the transition from a smaller number of cells in the second section 16 to a larger number of cells in the first section 15. The transition region 22 is flexible, particularly bend-flexible, and ensures good wall adaptation.

[0066] In the embodiments according to Figs. 1, 3, 7, and 8, the second section 16 has three cells 17 per circumferential segment 20, and the first section 15 has nine cells 18 per circumferential segment 21. In this case, the flexible transition region 22 is formed by a transition from a three-cell design of the second section 16 to a nine-cell design of the first section 15. The invention is not limited to a specific number of cells 13, 17, 18 per circumferential segment 20, 21. A different number of cells 13, 17, 18 is possible.

[0067] The cells 18 of the first section 15 are shorter in the axial direction of the lattice structure 11 than the cells 17 of the second section 16 (see Figs. 1, 3, 7, and 8). In other words, the cells 18 of the first section 15 are shorter than the cells 17 of the second section 16. Short cells 18 exhibit good adaptability to pronounced vessel curvatures.

[0068] In the embodiment shown here, the cells 17 of the second section

[0069] 16 is diamond-shaped. Figure 2 clearly shows that a strictly geometric diamond shape is not required. The sides of the diamond can be partially curved and partially straight. The basic shape of cell 17 is diamond-shaped.

[0070] The cells 17 of the second section 16 have a connecting web 29 that extends into the cell 17 and / or bridges it diagonally. The connecting web 29 divides the cell 17 into two sub-cells or partial cells that are essentially symmetrical. The partial cells are arranged between the webs 12 and the connecting web 29. The main cell 17 has X-shaped web connectors 30 at the diamond tips. Specifically, four X-shaped web connectors 30 are provided per main cell 17. The connecting web 29 is connected by a flexible, Z-shaped web connector 31.

[0071] The lattice structure 11 has at least one third section 23 for anchoring the device 10 in a vessel, which is substantially free of membrane 14. As can be seen in Fig. 3, the membrane 14 extends only partially into the proximal end region of the third section 23. The remaining part of the third section 23 is not covered by the membrane 14.

[0072] The third section 23 has a lattice structure 11 with closed cells 13,

[0073] 17. The cells 13, 17 of the third section 23 are essentially diamond-shaped. Specifically, six closed cells 13, 17 are provided per circumferential segment of the third section 23. The third section 23 has, as can be seen in Figs. 1, 7, and 8, a circumferential segment that forms the distal end segment of the lattice structure 11.

[0074] The third section 23 is arranged distally of the second section 16 and forms a distal end of the lattice structure 24. In this embodiment, the distal end of the lattice structure 24 serves to anchor the lattice structure 11 in the vessel.

[0075] The first section 15 is shorter than the third section 23 or the first section 15 has a shorter length than the second section 23. The open cells 18 of the first section 15 are shorter than the closed cells 17 of the third section 23. The proximal end segment 21 is shorter than the distal end segment.

[0076] The second section 16 is arranged between the first section 15 and the third section 23. The second section 16 adjoins the first section 15 at its proximal end and the third section 23 at its distal end.

[0077] In Figs. 3, 7, and 8, it can be seen that the third section 23 forms an enlarged diameter of the lattice structure 11 with a flaring angle b between two opposing flared webs 12 of the lattice structure 11. The third or distal section 23 of the lattice structure 11 forms a flared region of the lattice structure 11. The flaring angle b can be between 5° and 20°. The flaring angle is designed as a conical or tapered opening angle.

[0078] Figs. 3 and 8 show that the lattice structure 11 has a plurality of X-ray visible marker elements 25, with the first section 15 and the second section 16 each having a plurality of marker elements 25. The marker elements 25 mark the area of ​​the lattice structure 11 that is covered by the membrane 14. The marker elements 25 are arranged at the proximal and distal ends of the membrane 14, whereby the entire area of ​​the lattice structure 11 covered by the membrane 14 is X-ray visible.

[0079] In the embodiment according to Figs. 3, 4 and 8, the marker elements 25 are designed as marker sleeves 26 that are crimped onto the webs 12 of the lattice structure 11. The arrangement of the marker sleeves 26 is selected such that the area of ​​the lattice structure 11 covered by the membrane 14 is X-ray visible. It is conceivable that only the proximal end of the second section 16 and the distal end of the first section 15 are provided with marker sleeves 26 in order to make the proximal and distal ends of the membrane 14 visible under X-ray control. Alternatively, marker sleeves 26 can be distributed over the entire area of ​​the lattice structure 11 covered by the membrane 14.

[0080] The position of the marker sleeves 26 on the webs 12 is adjustable. Figs. 3 and 4 show that the marker sleeves 26 are arranged in the first section 15 in a central region of the connecting webs 29. Fig. 8 shows that the marker element 26 in the first section 15 is arranged on a web 12 of the diamond-shaped basic cell 17.

[0081] Figures 3, 7, and 8 further show that the lattice structure 11 is provided with end markers. X-ray-visible marker elements 25, designed as marker sleeves 26, are arranged at both the proximal and distal ends of the lattice structure 19, 24.

[0082] In the exemplary embodiment according to Fig. 6, the marker elements 25 are designed as a coating 27 which is materially connected to the webs 12 of the lattice structure 11. The coating 26 is formed from or consists of an X-ray-visible material. Fig. 6 shows that the X-ray-visible coating 26 is arranged in the first section 15 both in a central region of the connecting webs 29 and on webs 12 of the diamond-shaped basic cell 17. The arrangement of the coating 27 is selected such that the region of the lattice structure 11 covered by the membrane 14 is X-ray-visible. It is conceivable that only the proximal end of the second section 16 and the distal end of the first section 15 are provided with an X-ray-visible coating 27 in order to make the proximal and distal ends of the membrane 14 visible under X-ray control.Alternatively, the coated regions 27 can extend over the entire area of ​​the grid structure 11 covered by the membrane 14. Fig. 5 shows that an X-ray-visible wire element 28, specifically a DFT wire, is woven into the grid structure 11. The wire element 28 extends over the first section 15 and the second section 16 of the grid structure 11. Starting from the proximal end of the grid structure 19, the wire element 28 is woven into the webs 12, deflected at the distal end of the first section 15, and guided back to the proximal end of the grid structure 19. Due to the deflection of the wire element 29 at the distal end of the first section 15, the transition from the membrane-covered to the membrane-free part of the device 10 is X-ray-visible.

[0083] List of reference symbols

[0084] 10 medical device

[0085] 11 Lattice structure

[0086] 12 bridges

[0087] 13 cells

[0088] 14 Membran

[0089] 15 first section of the lattice structure

[0090] 16 second section of the lattice structure

[0091] 17 closed cells

[0092] 18 open cells

[0093] 19 proximal end of the lattice structure

[0094] 20 Circumferential segment of the second section

[0095] 21 circumferential segments of the first section

[0096] 22 Transition area between the first and second sections

[0097] 23 third section of the lattice structure

[0098] 24 distal end of the lattice structure

[0099] 25 marker element

[0100] 26 Marker sleeve

[0101] 27 X-ray visible coating

[0102] 28 radiopaque wire element

[0103] 29 Connecting bar 30 X-shaped bar connectors

[0104] 31 Z-shaped web connectors

Claims

Claims 1. A medical device (10) for treating vascular lesions, in particular aneurysms, comprising a compressible and expandable lattice structure (11) made of webs (12) that delimit cells (13) of the lattice structure (11), wherein the lattice structure (11) is covered at least in sections with a, in particular electrospun, membrane (14), characterized in that the lattice structure (11) has at least a first section (15) and at least a second section (16), wherein the first section (15) is arranged at an axial end (19) of the lattice structure (11) and has a length in the axial direction that is at most 15%, in particular at most 10%, of the length of the lattice structure (11), and wherein the first section (15) has open cells (17) and the second section (16) has closed cells (18), and the membrane (14) extends at least over the first and second sections (15, 16).

2. Medical device according to claim 1, characterized in that the first section (15) is arranged at the proximal end (19) of the lattice structure (11) and / or forms a proximal end (19) of the lattice structure (11).

3. Medical device according to claim 1 or 2, characterized in that the cells of the first section (15) have a shorter length in the axial direction of the lattice structure (11) than the cells of the second section (16).

4. Medical device according to one of the preceding claims, characterized in that the number of cells (17) of the second section (16) per circumferential segment (20) is smaller than the number of cells (18) of the first section (15) per circumferential segment (21).

5. Medical device according to one of the preceding claims, characterized in that the second section (16) has at least two cells (17) per circumferential segment (20) and the first section (15) has at least six cells (18) per circumferential segment (21).

6. Medical device according to one of the preceding claims, characterized in that the cells (17) of the second section (16) are substantially diamond-shaped and have a connecting web (29) which extends into the cell (17) and / or bridges it diagonally.

7. Medical device according to one of the preceding claims, characterized in that the lattice structure (11) has at least a third portion (23) for anchoring the device (10) in a vessel, which is substantially free of membrane (14).

8. Medical device according to claim 7, characterized in that the third section (23) is arranged distally of the second section (16) and / or forms a distal end (24) of the lattice structure (11).

9. Medical device according to claim 7 or 8, characterized in that the third section (23) forms an enlargement of the diameter of the lattice structure (11) with a flaring angle b, where b = 5° to 20°.

10. Medical device according to one of the preceding claims, characterized in that the lattice structure (11) has a plurality of X-ray visible marker elements (25), wherein the first section (15) and the second section (16) each have at least one marker element (25).

11. Medical device according to claim 10, characterized in that the marker elements (25) have a marker sleeve (26) which is Webs (12) of the lattice structure (11) are crimped, or be designed as a coating (27) that is materially bonded to the webs (12) of the lattice structure (11).

12. Medical device according to one of the preceding claims, characterized in that at least one X-ray-visible wire element (28), in particular DFT wire, is woven into the lattice structure (11) and extends at least over the first section (15) and the second section (16).

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