Medical device for treating vascular lesions

Abstract

Medical device (10) for treating vascular lesions, in particular aneurysms, having a compressible and expandable mesh structure (11) composed of struts (12) which define the mesh openings (13) of the mesh structure (11), wherein the mesh structure (11) is at least partially covered by a membrane (14), in particular an electrospun membrane, wherein the mesh 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 mesh structure (11) and has a length in axial direction of at most 15%, in particular at most 10%, of the length of the mesh structure (11), and wherein the first section (15) has open mesh openings (17) and the second section (16) has closed mesh openings (18), and the membrane (14) extends at least over the first and second sections (15, 16).

Description

[0001] The present invention relates to a medical device for treating vascular lesions, particularly aneurysms, having a compressible and expandable mesh structure composed of ribs defining the mesh openings, wherein the mesh structure is at least partially covered by a membrane, particularly an electrospun membrane.

[0002] The aforementioned medical device is known, for example, from DE 10 2018 131 269 A1, issued by the applicant. This device is capable of effectively treating vascular lesions. The device has a membrane configured to significantly reduce blood flow into the aneurysm, allowing the blood within the aneurysm to clot and form a thrombus.

[0003] For membrane-based medical devices, a common problem, especially in cases of highly tortuous blood vessels, is that these devices do not always possess sufficient flexibility to conform well to the vessel wall (wall fit). Therefore, there is a risk that blood may leak between the vessel wall and the device, and subsequently into an aneurysm (endoleak). Consequently, the aneurysm is not adequately isolated from the blood flow. Furthermore, there is a risk of vascular occlusion due to bending of the medical device.

[0004] Therefore, the object of the present invention is to provide a medical device for treating vascular lesions, particularly aneurysms, by which effective treatment of aneurysms can be achieved even under difficult conditions, such as when blood vessels are highly tortuous.

[0005] According to the present invention, the purpose of the medical device is achieved by the subject matter of claim 1.

[0006] Specifically, this objective is achieved by a medical device for treating vascular lesions, particularly aneurysms, having a compressible and expandable mesh structure composed of ribs defining the mesh openings, wherein the mesh structure is at least partially covered by a membrane, particularly an electrospun membrane. The mesh structure has at least a first segment and at least a second segment, wherein the first segment is arranged at the axial end of the mesh structure and has a length in the axial direction of at most 15%, particularly at most 10%, of the length of the mesh structure, and wherein the first segment has open mesh openings while the second segment has closed mesh openings, and the membrane extends at least over the first and second segments.

[0007] This invention has many advantages.

[0008] Therefore, this medical device can effectively treat vascular lesions even under challenging conditions (e.g., highly tortuous blood vessels). To this end, the device has a membrane that at least partially covers a mesh structure. This membrane is configured to significantly reduce blood flow into the vascular lesion or aneurysm, allowing the blood within the aneurysm to clot and form a thrombus. In this respect, the aneurysm naturally closes, ensuring that the thrombus cannot leave the aneurysm.

[0009] Another advantage of this invention is that the mesh structure of the supporting membrane provides both excellent wall-adherence and retraction capability of the device. To this end, the mesh structure is constructed in a hybrid manner. This hybrid design is achieved by the mesh structure having at least one first segment and at least one second segment, whose mesh openings are constructed in different ways. The first segment has open mesh openings (open-pore design), while the second segment has closed mesh openings (closed-pore design). Thus, the advantages of both closed-pore and open-pore designs are combined in one device. The open-pore design of the first segment achieves excellent wall-adherence, particularly in tortuous blood vessels. Conversely, the closed-pore design of the second segment enables retraction capability of the device.

[0010] The good wall-adherence of the first segment is achieved by constructing it to be relatively short or having a small length. Therefore, according to the invention, the length of the first segment in the axial direction is at most 15% of the length of the mesh structure. Particularly preferably, the length of the first segment is at most 10% of the length of the mesh structure. This smaller length advantageously allows the first segment to have an approximately circular cross-section in its expanded state, thereby enabling it to conform particularly well to the vessel wall during use. This is especially advantageous when the vessel is highly tortuous. The good wall-adherence of the first segment prevents blood from entering between the device and the vessel wall and pushing the membrane away from the vessel wall. This also prevents the mesh structure from bending, thereby preventing vascular occlusion.

[0011] By arranging the first segment at the axial end of the mesh structure, excellent wall-adhering fit or contact with the vessel wall is achieved at the end of the mesh structure. Therefore, the first segment forms a short end region of the device that optimally conforms to the vessel wall and prevents blood from flowing between the device and the vessel wall. In this way, it is ensured that the end of the mesh structure does not provide an intrusive area for blood flow. Therefore, blood cannot enter between the device and the vessel wall through the end of the mesh structure. Thus, blood flow around the device and / or into the aneurysm (endoleak) can be prevented. This ensures effective treatment of the aneurysm.

[0012] The closed-hole design of the second section is configured to achieve a high level of support and uniform load distribution of radial force on the vessel wall. This results in excellent anchoring of the device within the blood vessel.

[0013] If the open-aperture design is arranged unilaterally, particularly at the proximal end of the mesh structure, the closed-aperture design of the second segment also achieves the advantage of good resheathability for repositioning the device in the vessel. For example, if the length of the open mesh segment is 10% of the total length of the mesh structure, then 90% of the mesh structure is resheathable. This allows the operator to precisely position the device, especially the membrane, enabling effective treatment of aneurysms. Furthermore, it ensures that branch vessels are not covered by the membrane.

[0014] By limiting the length of the first section (specifically positioned near the proximal end of the mesh structure), good wall-hugging fit is achieved at the ends of the mesh structure, particularly near the proximal end, while also ensuring the device's retraction capability. To achieve good wall-hugging fit at the ends of the mesh structure, particularly near the proximal end, it is advantageous that the length of the first section with open mesh openings is at most 15% of the length of the mesh structure. By restricting the open mesh openings to the ends of the mesh structure, particularly near the proximal end, where the length is at most 15% of the mesh structure, the retraction capability of the mesh structure is also ensured.

[0015] The membrane is preferably arranged on the grid structure to avoid the formation of cavities (pocket formation) between the membrane and the vessel wall. This should preferably be understood as preventing the membrane from sinking between the ribs of the grid structure. In particular, the good wall-adherence of the first segment can reduce the risk of such cavity formation. Thus, good coverage of the aneurysm is achieved.

[0016] The membrane extends over a first and second segment of the mesh structure. Both the closed pores of the second segment and the open pores of the first segment are covered by the membrane. Because both segments are covered by the membrane, both segments can be used to cover the aneurysm. Particularly preferably, only the second segment is used to cover the aneurysm. Since the first segment is located at the axial end of the mesh structure, the membrane extends from one end of the mesh structure at least to the second segment. The advantage here is that the first segment of the mesh structure, with its good wall-adhering fit, can be used to cover the aneurysm even in cases of high vessel tortuosity, and / or adapts well to vessel tortuosity, thereby preventing endoleak.

[0017] Particularly preferably, the membrane of the device according to the invention is made by electrospinning, or the membrane is preferably formed from an electrospinned material. For membrane design, refer to the applicant's patents DE 10 2018 131 269 B4 or DE 10 2019135 502 B4.

[0018] The membrane advantageously allows for a certain degree of blood permeability. For this purpose, the membrane is preferably constructed to be porous or preferably has pores. This permeability facilitates the supply of nutrients to the cells of the aneurysm wall. This, in turn, prevents cell degeneration and the potential resulting aneurysm rupture.

[0019] Medical devices have a mesh structure, particularly tubular walls composed of a mesh structure. The mesh structure can be self-expanding or balloon-expanding.

[0020] A mesh structure can be a braided fabric composed of multiple braided threads or a single braided thread. A mesh structure can also be a one-piece mesh structure, such as a laser-cut mesh structure.

[0021] Preferred embodiments of the present invention are claimed or provided in the dependent claims.

[0022] In one embodiment, a first segment is disposed at and / or forms the proximal end of the mesh structure. The proximal end of the mesh structure has an open mesh or an open-pore design. The arrangement of open mesh is advantageously limited to the proximal end of the mesh structure. The remaining mesh structure is preferably formed by closed mesh. Since the proximal end of the mesh structure is the last to leave the delivery aid (e.g., catheter) when the device is delivered or positioned, the open-pore design of the proximal end hardly affects the repositionability of the device. For example, if the length of the first segment is at most 15% of the total length of the mesh structure, the remaining 85% of the mesh structure can be completely sheathed. Therefore, the device advantageously has good repositionability for repositioning the device in a blood vessel. Thus, optimal positioning of the device in a blood vessel can be achieved.

[0023] The number of mesh openings in each circumferential segment of the second section is advantageously less than the number of mesh openings in each circumferential segment of the first section. Both the first and second sections may each have multiple circumferential segments with multiple mesh openings interconnected in the circumferential direction. In one embodiment of the invention, the first section has a greater number of mesh openings per circumferential segment than the second section. By transitioning from a smaller number of mesh openings in the second section to a larger number of mesh openings in the first section, a flexible proximal region of the mesh structure can be provided, achieving good wall-adaptive fit. The large number of mesh openings in the flexible proximal region of the mesh structure and the end region of the device advantageously achieves good adaptation of the proximal end of the mesh structure to the vessel wall, particularly complex vascular geometries. This is particularly advantageous when the vessel is highly tortuous. Good wall-adaptive fit can reduce the risk of endoleak.

[0024] The second section may have at least two mesh openings per circumferential segment, while the first section may have at least six mesh openings per circumferential segment. Particularly preferably, the second section has three mesh openings per circumferential segment, wherein each mesh opening can be divided into two half-mesh openings by diagonally extending ribs. The first section preferably has nine mesh openings per circumferential segment. It has been shown that, in cases of highly tortuous blood vessels, nine mesh openings per circumferential segment in the first section of the device achieves a particularly good fit to the vessel wall. Furthermore, the preferred three-mesh design of the second section achieves high support or radial force and a uniform load distribution, while maintaining good flexibility of the mesh structure.

[0025] Preferably, the mesh openings in the first segment have a shorter length in the axial direction of the mesh structure than those in the second segment. The mesh openings in the first segment are preferably shorter than those in the second segment. By using shorter mesh openings or smaller mesh opening lengths, the wall-adaptability of the mesh structure or the first segment can be improved. Generally, as the number of mesh openings in each circumferential segment increases, the mesh openings can be constructed to be shorter. For example, the preferred nine mesh openings in the first segment can be constructed to be shorter than the preferred three mesh openings in the second segment. By using a large number of mesh openings with shorter lengths in the axial direction, an approximately circular cross-section can be achieved in the expanded state of the mesh structure. This advantageously achieves good adaptation of the mesh structure to the vessel wall.

[0026] The mesh of the second section is preferably constructed in a substantially rhomboid shape and has connecting ribs that extend into the mesh and / or diagonally span the mesh. The connecting ribs advantageously divide the mesh into two sub-mesh or partial mesh, particularly into two half-mesh, specifically two substantially symmetrical half-mesh, arranged between the ribs and the connecting ribs. The main mesh preferably has X-shaped rib connectors at the vertices of the rhomboid. Thus, each main mesh can have four X-shaped rib connectors. The connection of the connecting ribs can be achieved using flexible, particularly Z-shaped rib connectors.

[0027] Regarding the mesh design of the second section, referencing DE 10 2023 104 170 A1 from the applicant, according to that document, the second section preferably has a compressible and expandable mesh structure composed of ribs connected to each other by rib connectors and defining closed mesh openings of the mesh structure, wherein every two ribs of at least one mesh opening are arranged opposite each other to form a first rib pair and a second rib pair, and one of the two rib pairs is connected to each other by at least one connecting rib extending into the mesh opening and bridging the mesh opening.

[0028] The mesh openings of the first section can be configured to be substantially rhomboid. Preferably, each mesh opening in the first section is connected to an adjacent mesh opening in the circumferential direction only by one X-shaped rib connector. The mesh openings of those mesh openings that are adjacent in the circumferential direction but not connected by X-shaped rib connectors are advantageously interconnected, thus forming a common free surface or mesh opening. This achieves an open-type design for the first section.

[0029] Particularly preferably, the first section has only one circumferential segment, i.e., only one row of mesh openings. This single circumferential segment preferably forms the proximal end segment of the mesh structure. It is conceivable that the first section may have multiple circumferential segments, such as two or three circumferential segments. In any case, it is specified that the length of all circumferential segments of the first section in the axial direction is at most 15%, particularly at most 10%, of the length of the mesh structure.

[0030] The first segment, or preferably a circumferential segment of the first segment, transitions to the second segment via a flexible transition region, or forms a flexible transition region with the second segment. The mesh openings of the first segment, or a circumferential segment of the first segment, may partially form free ends (free rhombus vertices) in the distal direction (i.e., in the transition region). This should preferably be understood as: the mesh openings of the first segment are not partially connected to the mesh openings of the second segment in the transition region or in the distal direction. This is achieved, in particular, by transitioning from a smaller number of mesh openings in the second segment to a larger number of mesh openings in the first segment. Preferably, at least 3 / 4, particularly at least 2 / 3, particularly at least 1 / 2, of the mesh openings of the first segment form free ends (free rhombus vertices) in the distal direction. Conversely, it can be specified that at most 1 / 2, particularly at most 1 / 3, particularly at most 1 / 4, of the mesh openings of the first segment are connected to the mesh openings of the second segment in the distal direction. Thus, in the transition region, for example, a larger free surface is formed between the ribs compared to the second segment. Therefore, the transition region has good flexibility, particularly bending flexibility. This method improves the wall-mounting adaptability.

[0031] Decoupling between the first and second segments can be achieved by transitioning from a smaller number of mesh openings in the second segment to a larger number of mesh openings in the first segment, or through a transition region. This decoupling is advantageously achieved through a flexible transition region. The good wall-hugging adaptability of the first segment is almost unaffected by the remaining mesh structure.

[0032] The mesh structure may have at least one third segment for anchoring the device in a blood vessel, which is substantially membrane-free. This should preferably be understood as the third segment improving the device's anchorage in the blood vessel. The remaining segments of the mesh structure, namely the first and second segments, may also provide some anchorage themselves. The third segment enhances anchorage safety in the blood vessel or treatment site. The risk of migration is thus significantly reduced.

[0033] Preferably, the third segment is substantially without a membrane. This should preferably be understood as: the majority of the third segment is not covered by a membrane. It is conceivable that the membrane extends at least partially into the proximal region of the third segment. In use, the third segment is preferably positioned distal to the vascular lesion and, in this case, not used to cover the vascular lesion. Therefore, it is advantageous that the third segment is substantially without a membrane. The membrane preferably extends only over the first and second segments. Alternatively, it is conceivable that the membrane extends at least partially or completely over or covers the third segment of the mesh structure. Here, the third segment can be used, on the one hand, to cover the lesion, and on the other hand, to anchor the device in the blood vessel.

[0034] The third segment can be disposed distal to the first segment and / or at the distal end forming a mesh structure. In this case, the distal end of the mesh structure is used to anchor the device in the blood vessel. The third segment preferably has a mesh structure with closed openings. The openings of the third segment can be configured to be substantially rhomboid. Preferably, six closed openings are provided for each circumferential segment of the third segment. Each circumferential segment can have a different number of openings. For example, each circumferential segment of the third segment can have three to twelve openings. With the closed-hole design, the third segment has good resheathability for repositioning the device in the blood vessel. This is particularly advantageous because when the device is delivered or positioned, the distal end (i.e., the third segment with the mesh structure) exits the catheter first. With the closed-hole design, the third segment can resheath without any problems.

[0035] By preferably arranging the third segment at the far end of the grid structure and the second segment at the near end, the grid structure advantageously possesses an asymmetrical design. In this case, the far end has closed mesh openings, while the near end has open mesh openings, thus constructing an asymmetrical grid structure. In this way, the advantages of both open-cell and closed-cell designs can be combined in a single device.

[0036] Preferably, the third section forms a diameter-enlarged portion of a mesh structure, which has a flare angle b. For example, this radial expansion at the distal end can prevent the risk of support displacement. Furthermore, the transportability of the support is improved due to the smaller radial force in the flared region. Preferably, the flare angle b = 5° to 20°. Particularly preferably, the flare angle b is between 10° and 16°. It should be noted that a specific flare 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 flare angle b is typically applied when the flare is in a static state, i.e., when no external force is acting on the support, and is measured between two opposing ribs at the widened axial end. The flare angle b can be understood as the opening angle of a cone or circle.

[0038] In another embodiment, the grid structure has multiple developable marking elements, with the first and second sections each having at least one marking element. This provides the device with good developability. By arranging the marking elements on the first and second sections, the area of ​​the grid structure covered by the film is made clearly visible under X-ray control. This allows the operator to evaluate the device's opening behavior. It is conceivable that the first and second sections each have multiple marking elements, making the entire area of ​​the grid structure covered by the film visible under X-ray. The marking elements are preferably arranged in the middle regions of the ribs.

[0039] The marking element may have a marking sleeve that is press-fitted to the ribs of the grid structure. The marking sleeve is preferably C-shaped and formed of a developable material, such as a platinum-iridium alloy. The marking sleeve can be press-fitted to and thus connected to the ribs of the grid structure. Preferably, the marking sleeve is connected to the ribs of the grid structure before the film is applied to the grid structure.

[0040] Alternatively, the marking elements can be configured as a coating that is material-bonded to the ribs of the mesh structure. Here, a developable material can be applied to the surface of the ribs. It is conceivable that the coating is applied to the rib intersections, rib connectors, or the middle regions of the ribs. Preferably, the coating is applied to the ribs of the mesh structure before the film is applied to the mesh structure.

[0041] At least one radiopaque wire element, particularly a DFT wire, can be woven into the mesh structure and extends at least in the first and second segments. This advantageously makes the area covered by the membrane within the device clearly visible under radiation control. In this way, the membrane can be correctly positioned at the treatment site. Furthermore, the opening behavior of the device can be easily evaluated. One or more wires can be woven into the mesh structure. Preferably, the membrane is applied to the mesh structure after at least one wire element has been woven. Particularly preferably, at least one wire element is configured as a DFT wire and has a radiopaque core material and a hyperelastic covering material.

[0042] The present invention will now be described in more detail based on embodiments and with reference to the accompanying drawings. In these drawings: Figure 1 A unfolded diagram of a grid structure according to an embodiment of a medical device based on the present invention is shown; Figure 2 It shows according to Figure 1 A magnified partial view of the second segment of the grid structure; Figure 3 It shows according to Figure 1 A mesh structure for a medical device, wherein the mesh structure is partially covered by a membrane; Figure 4 It shows according to Figure 1 A magnified partial view of a grid structure, wherein the grid structure has developable marker elements; Figure 5 It shows according to Figure 1 A magnified partial view of the mesh structure, in which developable wire elements are woven into the mesh structure; Figure 6 It shows according to Figure 1 A magnified partial view of a mesh structure having a developable coating; Figure 7 It shows according to Figure 1 The grid structure of the medical device in its expanded, static state; and Figure 8 It shows according to Figure 1 The medical device in its expanded, static state has a grid structure, wherein the grid structure has marking elements.

[0043] Figure 3 An embodiment of a medical device 10 for treating vascular lesions according to the present invention is shown. Here, the device 10 is used as a stent, or generally as a temporary or permanent vascular implant. Specifically, the device 10 is used to treat aneurysms. Other applications are also conceivable. For example, the device 10 can be used to treat fistulas, dissections, or stenosis.

[0044] The device 10 has a compressible and expandable mesh structure 11, which is composed of ribs 12 that define the mesh openings 13 of the mesh structure 11. The mesh structure 11 is constructed as a single unit. The mesh structure 11 can be manufactured, for example, by laser cutting.

[0045] For clarity, Figure 1 , Figure 2 , Figure 4 , Figure 5 and Figure 6 The grid structure 11 in the image is shown in an expanded state. Figure 3 , Figure 7 and Figure 8 It is shown in the expanded static state, that is, no external force is acting on the grid structure 11.

[0046] from Figure 3 As can be seen, the mesh structure 11 is partially covered by the membrane 14. The membrane 14 is manufactured by an electrospinning process. The membrane 14 is formed of or composed of electrospinned materials. For example, the membrane 14 is formed of perfluorinated or partially fluorinated polymers (e.g., PTFE, PVDF), polyolefins (e.g., PP, PE), polyurethanes (e.g., thermoplastic polyurethane, hydrophilic polyurethane), polyamides (e.g., 35PA6.6), polyesters (e.g., PLA, PLGA, PET), polysulfones (e.g., PSU), polyetheretherketones (PEEK), biopolymers, and / or protein-based polymers.

[0047] The mesh structure 11 is constructed as a hybrid type. It can be seen that the hybrid design is achieved in the following way: the mesh structure 11 has a first segment 15 with open mesh openings 18 (open-cell design) and a second segment 16 with closed mesh openings 17 (closed-cell design) (see...). Figure 1 , Figure 3 , Figure 7 and Figure 8 ).

[0048] The closed mesh 17 of the second section 16 is configured to ensure high support strength of the mesh structure 11 and to ensure uniform load distribution of radial forces on the vessel wall. The closed mesh 17 also provides good repositioning capability to ensure repositioning of the device 10 within the vessel.

[0049] Figure 1 , Figure 3 , Figure 7 and Figure 8As shown, each open mesh 18 of the first segment 15 is connected to its circumferentially adjacent mesh 18 only by one X-shaped rib connector 30. The mesh openings of those circumferentially adjacent meshes 18 that are not connected to each other by the X-shaped rib connector 30 are interconnected, forming a common free surface or mesh opening. Here, the open meshes 18 of the first segment 15 ensure good wall fit, especially in highly tortuous blood vessels.

[0050] The first section 15 is located at the axial end 19 of the grid structure 11 (see...). Figure 1 , Figure 3 , Figure 7 and Figure 8 The perforated design is limited to the ends 19 of the grid structure.

[0051] According to Figure 1 , Figure 3 , Figure 7 and Figure 8 In one embodiment, the first segment 15 has a circumferential segment 21 with nine open mesh openings 18. Here, the circumferential segment 21 with nine open mesh openings 18 forms the proximal end segment of the mesh structure 11.

[0052] A circumferential segment 21 of the first section 15 transitions to the second section 16 via a transition region 22. The mesh 18 of the circumferential segment 21 of the first section 15 partially forms free ends (free rhombus vertices) in the distal direction (i.e., in the transition region 22), or is not connected to the mesh 17 of the second section 16 in the axial direction. Specifically, the rhombus vertices of six of the nine meshes 18 of the circumferential segment 21 form free rhombus vertices. The rhombus vertices of the remaining three meshes 18 are connected to the rhombus vertices of the mesh 17 of the second section 16 in the axial direction. Thus, a large free surface is formed between the ribs 12 in the transition region 11, for example, compared to the meshes 18 of the second section 16. Therefore, the transition region 22 has good bending flexibility, which achieves good wall-hugging adaptability.

[0053] Figure 1 , Figure 3 , Figure 7 and Figure 8 As shown, the first segment 15 occupies a small proportion of the total length of the device 10 or the mesh structure 11. Specifically, the length of the first segment 15 is at most 15% of the length of the mesh structure 11. This smaller length of the first segment 15 allows for a particularly good fit to the vessel wall or excellent wall-adherence during use. This excellent wall-adherence of the first segment 15 prevents blood from leaking out from the axial end 19 of the mesh structure into the space between the device 10 and the vessel wall, and pushes the membrane 14 away from the vessel wall. Therefore, blood flow into the aneurysm (endoleak) can be prevented.

[0054] The first segment 15 is shorter than the second segment 16, or the first segment 15 has a shorter length than the second segment 16. The open segment 15 is shorter than the closed segment of the grid structure 11.

[0055] Because the perforated first segment 15 has a relatively short length and is confined to the axial end of the mesh structure 11, the device 10 is retractable. If the length of the perforated segment 15 is 15% of the total length of the mesh structure 11, then the remaining 85% of the mesh structure 11 with closed mesh 17 is also retractable. This allows the operator to precisely position the device 10, particularly the membrane 14, thereby enabling effective treatment of aneurysms. Furthermore, it ensures that branch vessels are not covered by the membrane 14.

[0056] According to Figure 3 In the embodiment, it can be seen that the membrane 14 extends over the first section 15 and the second section 16. The membrane 14 covers the closed mesh 17 of the second section 16 and the open mesh 18 of the first section 15.

[0057] The first section 15 is located at or forms the proximal end 19 of the mesh structure. The open design is limited to the proximal end 19 of the mesh structure. In this way, the open mesh 18 ensures good wall-fitting at the proximal end 19 of the mesh structure without significantly affecting the repositionability of the device 10.

[0058] By limiting the length of the first segment 15, good wall-hugging fit at the proximal end 19 of the mesh structure is achieved, while the retractability of the device 10 is also ensured. Here, to achieve good wall-hugging fit at the proximal end 19 of the mesh structure, a maximum length of 15% of the length of the perforated first segment 15 is sufficient. By restricting the open mesh 18 to the proximal end 19 of the mesh structure (with a length at most 15% of the mesh structure 11), the retractability of the mesh structure 11 is further ensured.

[0059] like Figure 1 , Figure 3 , Figure 7 and Figure 8 As shown, the number of mesh openings 17 in each circumferential segment 20 of the second segment 16 is less than the number of mesh openings 18 in each circumferential segment 21 of the first segment 15. Each circumferential segment 21 of the first segment 15 has more mesh openings 18 than the second segment 16. The relatively larger number of mesh openings in the first segment 15 results in an approximately circular cross-section for the first segment 15 in its expanded state. Consequently, the first segment 15 exhibits good adaptability to the vessel wall, or good wall-adhering fit.

[0060] A transition region 22 is formed by transitioning from a smaller number of mesh openings in the second section 16 to a larger number of mesh openings in the first section 15. The transition region 22 is flexible, particularly flexible in bending, and ensures good wall-hugging adaptability.

[0061] According to Figure 1 , Figure 3 , Figure 7 and Figure 8 In one embodiment, each circumferential segment 20 of the second segment 16 has three mesh openings 17, and each circumferential segment 21 of the first segment 15 has nine mesh openings 18. In this case, the flexible transition region 22 is formed by transitioning from the three-hole design of the second segment 16 to the nine-hole design of the first segment 15. The invention is not limited to each circumferential segment 20, 21 having a specific number of mesh openings 13, 17, 18. Other numbers of mesh openings 13, 17, 18 are possible.

[0062] The mesh 18 of the first segment 15 has a smaller length in the axial direction of the mesh structure 11 than the mesh 17 of the second segment 16 (see [link]). Figure 1 , Figure 3 , Figure 7 and Figure 8 In other words, the mesh 18 of the first segment 15 is configured to be shorter than the mesh 17 of the second segment 16. The shorter mesh 18 provides a good fit for highly tortuous blood vessels.

[0063] In the embodiment shown here, the mesh 17 of the second segment 16 is diamond-shaped. Figure 2 As can be clearly seen, a strict geometric rhombus shape is not required. The sides of the rhombus can be partially curved and partially straight. The basic shape of mesh 17 is a rhombus.

[0064] The mesh 17 of the second section 16 has connecting ribs 29 that extend into and / or diagonally span the mesh 17. The connecting ribs 29 divide the mesh 17 into two substantially symmetrical sub-mesh areas or portions of the mesh. These portions are arranged between the ribs 12 and the connecting ribs 29. The main mesh 17 has X-shaped rib connectors 30 at the rhomboid apex. Specifically, each main mesh 17 has four X-shaped rib connectors 30. The connecting ribs 29 are connected by flexible Z-shaped rib connectors 31.

[0065] The mesh structure 11 has at least one third segment 23 for anchoring the device 10 in a blood vessel, the third segment being substantially without a membrane 14. Figure 3 As shown, membrane 14 extends only partially into the proximal end region of the third segment 23. The remaining portion of the third segment 23 is not covered by membrane 14.

[0066] The third section 23 has a mesh structure 11 with closed mesh openings 13 and 17. The mesh openings 13 and 17 of the third section 23 are constructed in a substantially rhomboid shape. Specifically, each circumferential segment of the third section 23 has six closed mesh openings 13 and 17. Figure 1 , Figure 7 and Figure 8 As shown, the third section 23 has a circumferential section that forms the far end section of the grid structure 11.

[0067] The third segment 23 is disposed at the distal end of the second segment 16 and forms the distal end 24 of the mesh structure. In this embodiment, the distal end 24 of the mesh structure is used to anchor the mesh structure 11 in the blood vessel.

[0068] The first segment 15 is shorter than the third segment 23, or the length of the first segment 15 is shorter than the length of the second segment 23. The open mesh 18 of the first segment 15 is shorter than the closed mesh 17 of the third segment 23. The proximal end segment 21 is shorter than the distal end segment.

[0069] The second segment 16 is disposed between the first segment 15 and the third segment 23. The second segment 16 is adjacent to the first segment 15 at its proximal end and to the third segment 23 at its distal end.

[0070] exist Figure 3 , Figure 7 and Figure 8 As can be seen, the third segment 23 forms the diameter enlargement of the grid structure 11, which has a flaring angle b between two opposing flaring ribs 12 of the grid structure 11. The third segment 23 or the distal segment 23 of the grid structure 11 forms the flared region of the grid structure 11. The flaring angle b can be between 5° and 20°. The flaring angle is configured as a conical or conical opening angle.

[0071] Figure 3 and Figure 8 As shown, the mesh structure 11 has a plurality of developable marker elements 25, wherein the first segment 15 and the second segment 16 each have a plurality of marker elements 25. The marker elements 25 mark the areas in the mesh structure 11 covered by the film 14. The marker elements 25 are arranged at the proximal and distal ends of the film 14, so that the entire area in the mesh structure 11 covered by the film 14 is visible under X-rays.

[0072] According to Figure 3 , Figure 4 and Figure 8In one embodiment, the marking element 25 is configured as a marking sleeve 26, which is pressed onto the ribs 12 of the mesh structure 11. The marking sleeve 26 is arranged such that the area of ​​the mesh structure 11 covered by the membrane 14 is visible under radiation. It is conceivable that the marking sleeve 26 is provided only at the proximal end of the second segment 16 and the distal end of the first segment 15 so that the proximal and distal ends of the membrane 14 are visible under radiation control. Alternatively, the marking sleeve 26 may be distributed across the entire area of ​​the mesh structure 11 covered by the membrane 14.

[0073] The position of the marking sleeve 26 on the reinforcing bar 12 is adjustable. Figure 3 and Figure 4 As shown, the marking sleeve 26 is arranged in the middle region of the connecting rib 29 in the first section 15. Figure 8 As can be seen, the marking element 26 is arranged on the ribs 12 of the diamond-shaped basic mesh 17 in the first section 15.

[0074] Figure 3 , Figure 7 and Figure 8 It is also shown that the mesh structure 11 is provided with end markings. At the proximal end 19 and distal end 24 of the mesh structure, a recognizable marking element 25 is arranged, which is configured as a marking sleeve 26.

[0075] According to Figure 6 In one embodiment, the marking element 25 is configured as a coating 27, which is connected to the ribs 12 of the mesh structure 11 in a material-bonded manner. The coating 26 is formed of or constitutes a developable material. Figure 6 As shown, a developable coating 26 in the first segment 15 is arranged in the middle region of the connecting ribs 29 and on the ribs 12 of the diamond-shaped basic mesh 17. The arrangement of the coating 27 is chosen such that the area of ​​the mesh structure 11 covered by the film 14 is visible under X-rays. It is conceivable that only the proximal end of the second segment 16 and the distal end of the first segment 15 are provided with the developable coating 27 so that the proximal and distal ends of the film 14 are visible under X-ray control. Alternatively, the coated area 27 may extend to cover the entire area of ​​the mesh structure 11 covered by the film 14.

[0076] Figure 5As shown, a developable wire element 28, specifically a DFT wire, is woven into a mesh structure 11. The wire element 28 extends over a first segment 15 and a second segment 16 of the mesh structure 11. The wire element 28 is woven into the reinforcing ribs 12 starting from the proximal end 19 of the mesh structure, deflected at the distal end of the first segment 15, and guided back to the proximal end 19 of the mesh structure. The transition from the membrane-covered portion to the unmembrane portion of the device 10 is visible under X-rays via the deflection of the wire element 29 at the distal end of the first segment 15.

[0077] Reference tag list 10 Medical Devices 11. Mesh Structure 12 reinforcing bars 13 mesh 14 Membrane 15. The first section of the grid structure 16. The second section of the grid structure 17 Closed mesh 18 Open mesh 19. Proximal end of the grid structure 20. Circumferential section of the second segment 21. Circumferential section of the first segment 22. Transition area between the first and second sections 23. The third section of the grid structure 24. The far end of the grid structure 25 Marking elements 26 Marking sleeve 27. Developable coating 28. Developable wire components 29 Connecting ribs 30 X-shaped stiffener connector 31 Z-shaped rib connector.

Claims

1. A medical device (10) for treating vascular lesions, particularly aneurysms, the medical device having a compressible and expandable mesh structure (11) composed of ribs (12) defining mesh openings (13) of the mesh structure (11), wherein the mesh structure (11) is at least partially covered by a membrane (14), particularly an electrospun membrane. Its features are, The mesh structure (11) has at least one first segment (15) and at least one second segment (16), wherein the first segment (15) is arranged at the axial end (19) of the mesh structure (11) and has a length in the axial direction of at most 15%, particularly at most 10%, of the length of the mesh structure (11), and wherein the first segment (15) has open mesh (17) and the second segment (16) has closed mesh (18), and the membrane (14) extends at least on the first segment and the second segment (15, 16).

2. The medical device according to claim 1, characterized in that, The first segment (15) is arranged at the proximal end (19) of the mesh structure (11) and / or forms the proximal end (19) of the mesh structure (11).

3. The medical device according to claim 1 or 2, characterized in that, The mesh of the first section (15) has a smaller length in the axial direction of the mesh structure (11) than the mesh of the second section (16).

4. The medical device according to any one of the preceding claims, characterized in that, The number of meshes (17) in each circumferential segment (20) of the second section (16) is less than the number of meshes (18) in each circumferential segment (21) of the first section (15).

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

6. The medical device according to any one of the preceding claims, characterized in that, The mesh (17) of the second section (16) is configured to be substantially rhomboid and has connecting ribs (29) that extend into the mesh (17) and / or cross the mesh (17) diagonally.

7. The medical device according to any one of the preceding claims, characterized in that, The mesh structure (11) has at least one third segment (23) for anchoring the device (10) in a blood vessel, the third segment being substantially without a membrane (14).

8. The medical device according to claim 7, characterized in that, The third segment (23) is arranged at the far end of the second segment (16) and / or forms the far end (24) of the grid structure (11).

9. The medical device according to claim 7 or 8, characterized in that, The third section (23) forms the diameter enlargement of the grid structure (11), the diameter enlargement having an flare angle b, where b = 5° to 20°.

10. The medical device according to any one of the preceding claims, characterized in that, The grid structure (11) has a plurality of developable marker elements (25), wherein the first segment (15) and the second segment (16) each have at least one marker element (25).

11. The medical device according to claim 10, characterized in that, The marking element (25) has a marking sleeve (26) which is pressed onto the ribs (12) of the grid structure (11), or the marking element (25) is configured as a coating (27) which is connected to the ribs (12) of the grid structure (11) by a material bonding manner.

12. The medical device according to any one of the preceding claims, characterized in that, At least one printable wire element (28), particularly DFT wire, is woven into the mesh structure (11) and extends at least on the first segment (15) and the second segment (16).

Images