Covered stent

Abstract

The application provides a covered stent, which comprises a main stent with a tubular main body, the main stent comprises a proximal end section, a tumor cavity section and a distal end section along the axial direction; the proximal end section is connected to the proximal end of the tumor cavity section, and the distal end section is connected to the distal end of the tumor cavity section; the tumor cavity section is provided with an internal iliac channel and an external iliac channel arranged in the radial direction, the external iliac channel is provided with a first embedded stent, the internal iliac channel is provided with a second embedded stent, and the first embedded stent is in communication with the distal end section; the distal end of the tumor cavity section is provided with an opening, and the distal end port of the second embedded stent is in communication with the opening; the first embedded stent and the second embedded stent are arranged to separate the internal iliac channel and the external iliac channel and reduce the mutual influence between the smaller channels; the radial support strength of the first embedded stent and the external iliac channel is greater than that of the second embedded stent and the internal iliac channel, so that when the tumor cavity section is compressed, the first embedded stent has a small deformation amount due to good support strength, maintains a better external iliac channel shape, and ensures the blood flow passability of the external iliac channel.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, and more particularly to a covered stent. Background Technology

[0002] The iliac arteries include the common iliac artery, external iliac artery, and internal iliac artery. Current techniques for treating iliac artery aneurysms involve endovascular treatment, implanting an iliac artery bifurcation stent and an internal iliac artery covered stent to reconstruct the artery. Existing iliac artery bifurcation stents typically have two branch channels, one for reconstructing the internal iliac artery and the other for the external iliac artery. To ensure the internal iliac artery channel is not blocked by vascular compression, its waveform design provides a certain level of support. However, the patency of the external iliac artery channel is far more important than that of the internal iliac artery channel. Therefore, the external iliac artery is generally designed with a larger lumen to ensure patency. However, an excessively large external iliac artery lumen places higher demands on the patient's vascular anatomy and limits the applicability of the devices. Summary of the Invention

[0003] Therefore, it is necessary to provide a new covered stent that can shunt blood flow between the internal and external iliac tracts while ensuring better channel retention in the external iliac tract portion under compression, thus maintaining good blood flow permeability at all times.

[0004] A covered stent includes a main stent having a tubular body, the main stent comprising a proximal segment, a lumbar segment, and a distal segment along an axial direction; the proximal segment communicates with the distal segment through the lumbar segment; the lumbar segment has a radially arranged internal iliac channel and an external iliac channel, the external iliac channel has a first embedded stent, and the internal iliac channel has a second embedded stent, the first embedded stent communicating with the distal segment; the distal end of the lumbar segment has an opening communicating with the outside, and the distal end of the second embedded stent communicates with the opening; the support strength of the first embedded stent and the external iliac channel is greater than the support strength of the second embedded stent and the internal iliac channel.

[0005] In one embodiment, the external iliac channel houses the first embedded stent, the internal iliac channel houses the second embedded stent, and the support strength of the first embedded stent is greater than the support strength of the second embedded stent and / or the support strength of the external iliac channel is greater than the support strength of the internal iliac channel.

[0006] In one embodiment, the first embedded stent and the second embedded stent include a mesh body, and the aneurysm segment includes a plurality of first wave coils spaced apart along the axial direction.

[0007] In one embodiment, the wire diameter of the first embedded stent is greater than that of the second embedded stent, and / or the wire diameter of the first wave loop located at the external iliac channel is greater than that of the first wave loop located at the internal iliac channel.

[0008] In one embodiment, the grid density of the first embedded stent is greater than that of the second embedded stent, and / or the wave angle of the first wave loop located at the external iliac channel is greater than that of the first wave loop located at the internal iliac channel.

[0009] In one embodiment, the axial length of the external iliac channel is greater than the axial length of the internal iliac channel, and the distal end of the second embedded stent includes an exposed section that extends through the opening.

[0010] In one embodiment, the first wave loop, located at least in the same axial position as the exposed segment, has a break, with the break facing the exposed segment.

[0011] In one embodiment, a transition wave loop is provided at the proximal end of the tumor cavity segment, and the proximal diameter of the transition wave loop is smaller than its distal diameter.

[0012] In one embodiment, the surface of the main support is covered with a first film, and the surfaces of the first embedded support and the second embedded support are covered with a second film, wherein the support strength of the first film is greater than the support strength of the second film.

[0013] In one embodiment, the support strength of the distal segment and the proximal segment is greater than the total support strength of the aneurysm segment, the first embedded stent, and the second embedded stent.

[0014] In one embodiment, the support strength of the distal segment or the proximal segment is greater than the total support strength of the aneurysm segment, the first embedded stent, and the second embedded stent.

[0015] The beneficial effects of this invention are as follows: Compared with the prior art, this invention provides a covered stent, including a main stent with a tubular body, the main stent comprising a proximal segment, a lumbar segment, and a distal segment along the axial direction; the proximal segment is connected to the proximal end of the lumbar segment, and the distal segment is connected to the distal end of the lumbar segment; the lumbar segment has a radially arranged internal iliac channel and an external iliac channel, the external iliac channel has a first embedded stent, and the internal iliac channel has a second embedded stent, the first embedded stent communicating with the distal segment; the distal end of the lumbar segment has an opening, and the distal end of the second embedded stent communicates with the opening; the first and second embedded stents separate the internal iliac channel and the external iliac channel, reducing the mutual influence between the channels; the radial support strength of the first embedded stent and the external iliac channel is greater than the radial support strength of the second embedded stent and the internal iliac channel, so that when the lumbar segment is compressed, the first embedded stent, due to its better support strength, has less deformation, maintains a better external iliac channel morphology, and ensures the blood flow through the external iliac channel. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of the film-coated stent in Embodiment 1 of the present invention;

[0017] Figure 2 This is a schematic diagram of the main support structure in Embodiment 1 of the present invention;

[0018] Figure 3 This is a schematic diagram of the embedded support structure in Embodiment 1 of the present invention;

[0019] Figure 4 This is a schematic diagram of the wave angle distribution structure of the first wave loop in Embodiment 1 of the present invention;

[0020] Figure 5 This is a schematic diagram of the first wave loop angle tapering structure in Embodiment 1 of the present invention;

[0021] Figure 6 This is a schematic diagram of the wire diameter distribution structure of the first wave loop in Embodiment 1 of the present invention;

[0022] Figure 7 This is a schematic diagram of the support structure of the first wave coil with different lengths in Embodiment 2 of the present invention;

[0023] Figure 8 This is a schematic diagram of the support structure at different heights for the first wave ring in Embodiment 2 of the present invention;

[0024] Figure 9 This is a structural schematic diagram of the second embodiment of the present invention when the support member is an elastic support member;

[0025] Figure 10 This is a schematic diagram of the structure of the film-coated stent in other embodiments of Embodiment 2 of the present invention;

[0026] Figure 11This is a schematic diagram of the main support structure in Embodiment 3 of the present invention;

[0027] Figure 12 This is a schematic diagram of the fracture structure in the first wave coil of Embodiment 3 of the present invention;

[0028] Figure 13 This is a schematic diagram of the overall structure of the membrane-covered stent in Embodiment 4 of the present invention;

[0029] Figure 14 This is a schematic diagram of the different wire diameter structures of the first embedded bracket and the second embedded bracket in Embodiment 4 of the present invention;

[0030] Figure 15 For the present invention Figure 14 Enlarged view of part A in the middle;

[0031] Figure 16 This is a schematic diagram of the different grid density structures of the first embedded bracket and the second embedded bracket in Embodiment 5 of the present invention;

[0032] Figure 17 This is a schematic diagram showing that the internal iliac channel and external iliac channel of the tumor cavity segment in Embodiment Six of the present invention have different axial lengths.

[0033] Figure 18 This is a schematic diagram of the exposed section of the second embedded bracket in Embodiment Six of the present invention.

[0034] Figure 19 This is a schematic diagram of the oblique opening structure of the exposed section of the second embedded bracket in Embodiment Six of the present invention;

[0035] Figure 20 This is a schematic diagram of a variable-diameter proximal waveguide structure provided at the proximal end of the tumor cavity segment in Embodiment Six of the present invention;

[0036] Figure 21 This is a schematic diagram of other film-coated scaffold structures in Embodiment Six of the present invention;

[0037] Figure 22 This is a schematic diagram of the film-coated scaffold structure in Embodiment 7 of the present invention;

[0038] Figure 23 This is a schematic diagram of the main support structure in Embodiment 7 of the present invention;

[0039] Figure 24 This is a schematic diagram showing the different axial lengths of the first embedded bracket and the second embedded bracket in Embodiment 7 of the present invention;

[0040] Figure 25 This is a schematic diagram of the triangular wave coil support structure in Embodiment 7 of the present invention;

[0041] Figure 26This is a schematic diagram of the structure with developing elements at both ends of the first and second embedded supports in Embodiment 7 of the present invention;

[0042] Figure 27 This is a schematic diagram of the wave ring support structure used in the transition support of Embodiment 7 of the present invention;

[0043] Figure 28 This is a schematic diagram of the mesh braided support structure used in the transition support of Embodiment 7 of the present invention;

[0044] Figure 29 This is a schematic diagram of the irregular waveguide structure in Embodiment 8 of the present invention;

[0045] Figure 30 This is a schematic diagram of the high-wave gradient structure at the far end of the irregular wave loop in Embodiment 8 of the present invention;

[0046] Figure 31 These are schematic diagrams of the hook and hanging rod structures in Embodiments 9 and 10 of the present invention;

[0047] Figure 32 This is a schematic diagram of the support conveying system in Embodiment 10 of the present invention;

[0048] Figure 33 This is a schematic diagram of the structure of the film-coated support inside the conveyor in Embodiment 10 of the present invention. Detailed Implementation

[0049] To better understand the concept of this application, the implementation methods of this application will be described in detail below with reference to the accompanying drawings. The following specific embodiments are only some embodiments of this application and are not intended to limit this application.

[0050] For ease of description, spatial relative terms may be used in the text to describe the relationship of one element or feature relative to another element or feature, as shown in the figure. These relative terms include, for example, "inside," "outside," "middle," "outer," "below," "below," "above," "over," etc. Such spatial relative terms are intended to include different orientations of the device in use or operation, other than those depicted in the figure. For example, if the device in the figure is flipped, an element described as "below other elements or features" or "below other elements or features" would subsequently be oriented as "above other elements or features" or "above other elements or features." Therefore, the example term "below" can include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or in other directions), and the spatial relative descriptors used in the text will be interpreted accordingly.

[0051] Although terms such as first, second, third, etc., may be used in this document to describe multiple elements, components, regions, layers, and / or segments, these elements, components, regions, layers, and / or segments should not be limited by these terms. These terms may be used only to distinguish one element, component, region, layer, or segment from another. Unless the context clearly indicates otherwise, terms such as "first," "second," and other numerical terms used herein do not imply order or sequence. Therefore, the first element, component, region, layer, or segment discussed below may be referred to as the second element, component, region, layer, or segment without departing from the teachings of the exemplary embodiments.

[0052] To more clearly describe the structure of this application, the terms "proximal" and "distal" are used here as conventional terms in the field of interventional medicine. Specifically, "distal" refers to the end of the blood vessel furthest from the heart, and "proximal" refers to the end of the blood vessel closest to the heart; "axial" refers to its length direction, and "radial" refers to the direction perpendicular to the "axial" direction; "upper end" and "lower end" refer to two relatively distant ends, and when one end is defined as "upper end", the other distant end is "lower end".

[0053] Example 1:

[0054] Please see Figures 1-2 This invention provides a covered stent 100, which typically consists of a metal skeleton and a covering material. The metal skeleton can be designed with a Z-shaped wave or a woven mesh. The covering material has a certain blood flow isolation capability and is combined with the metal skeleton through methods such as pressure heating and suturing to form a complete covered stent 100. The proximal end of the covered stent 100 is generally placed in the common iliac artery or connected to an abdominal aortic stent, and the lumen diameter is generally matched with the diameter of the common iliac artery. In this embodiment, see reference... Figure 1 and Figure 3The covered stent 100 has a main stent 10 with a tubular body and an embedded stent 20. The main stent 10 is placed directly inside the blood vessel and contacts the vessel wall. The embedded stent 20 is located within the lumen of the main stent 10 for blood flow shunting. The surface of the main stent 10 is covered with a first covering 104, and the surface of the embedded stent 20 is covered with a second covering 202. The main stent 10 includes a proximal segment 101, a lumen segment 102, and a distal segment 103 along its axial direction. The proximal segment 101 is connected to the proximal side of the lumen segment 102, and the distal segment 103 is connected to the distal side of the lumen segment 102. The proximal segment 101 communicates with the distal segment 103 through the lumen segment 102. 02 When the covered stent 100 is implanted into the diseased blood vessel, it is generally placed in the aneurysm cavity. The aneurysm cavity segment 102 is composed of the external iliac channel 1022 and the internal iliac channel 1021 arranged radially. The radial width of the aneurysm cavity segment 102 is usually set greater than the diameter of the distal segment 103 and the diameter of the proximal segment 101, ensuring sufficient flow space for both the internal iliac channel 1021 and the external iliac channel 1022 within the aneurysm cavity segment 102 to prevent complete occlusion due to compression of the aneurysm cavity after implantation. The external iliac channel 1022 and the internal iliac channel 1021 are isolated to form two relatively independent blood flow channels. During use, the internal iliac channel 1021 is used to insert the internal iliac stent. The external channel 1022 is used to connect the extended distal segment 103 to establish flow with the external iliac artery. In this embodiment, by placing the embedded stent 20 within the internal iliac channel 1021, the internal iliac channel 1021 and the external iliac channel 1022 are relatively independent and isolated. Furthermore, the distal end of the internal iliac channel 1021 has an opening 1024 for communication with the outside, and the distal end of the embedded stent 20 communicates with the opening 1024. The placement of the embedded stent 20 allows the shape of the formed internal iliac channel 1021 to match the shape of the internal iliac stent to be implanted, thereby ensuring better fit of the stent both during and after implantation. The embedded stent 20 is placed within the internal iliac channel 1021. At 021, at least part of the internal iliac passage 1021 of the aneurysm segment 102 is connected to the side wall. Preferably, the connection between the embedded stent 20 and the aneurysm segment 102 is a multi-point adhesive or sutured surface contact connection. This arrangement ensures that at least the part of the embedded stent 20 connected to the aneurysm segment 102 always remains in contact with the aneurysm segment 102 of the main stent 10. When the aneurysm segment 102 is compressed, the contact part can deform simultaneously with the deformation of the aneurysm segment 102, thereby effectively preventing the embedded stent 20 from not deforming when the aneurysm segment 102 deforms, but only displacing within the cavity of the aneurysm segment 102, which would affect the width and passage of the external iliac passage 1022.

[0055] In this embodiment, please refer to Figure 1 and Figure 2To ensure that the internal iliac passage 1021 of the covered stent 100 receives sufficient support from the embedded stent 20 when subjected to compression, while simultaneously ensuring that the external iliac passage 1022 maintains a good shape and avoids occlusion due to excessive compression, the total support strength of the internal iliac passage 1021 and the embedded stent 20 of the covered stent 100 in this application is set to be less than the support strength of the external iliac passage 1022. Thus, the portion with lower support strength deforms preferentially and with greater deformation under compressive force, while the portion with higher support strength deforms slowly and with limited deformation. Therefore, the iliac passage 1022... The external iliac channel 1022 has greater support strength, which ensures that it deforms less when subjected to the same compressive force as the internal iliac channel 1021, thus maintaining the shape of the external iliac channel 1022. The internal iliac channel 1021, due to its lower support strength, deforms preferentially and with greater deformation, causing more deformation of the aneurysm segment 102 to fall on the internal iliac channel 1021, thus maintaining the shape of the external iliac channel 1022. Due to the setting of the embedded stent 20, the part of the embedded stent 20 that is not connected to the aneurysm segment 102 in the cavity does not deform much and can still maintain a good channel shape.

[0056] In this embodiment, please refer to Figure 3 The embedded stent 20 has a mesh body 201 and a second covering 202. The mesh body 201 adopts a mesh-woven stent structure. The mesh support structure can provide better tension, thereby providing better shape retention. Furthermore, the mesh body 201 can provide more contact points during the implantation of the internal iliac stent, thereby increasing the friction between the internal iliac stent and the embedded stent 20, which can effectively enhance the adhesion and stent anti-slip performance. Please refer to [link to relevant documentation]. Figure 2 The proximal segment 101 has multiple proximal support coils 1011 along the axial direction, and the distal segment 103 has multiple distal support coils 1031 along the axial direction. Both the proximal support coils 1011 and the distal support coils 1031 adopt Z-shaped annular coils to provide support. The Z-shaped annular coils can provide support while leaving a covering gap between the coils, allowing the stent to deform at the covering gap, thus exhibiting good flexibility. The diameter of the proximal support coils 1011 is larger than the diameter of the distal support coils 1031 to accommodate different vessel diameters. In other embodiments, the mesh body can also be formed by cutting tubular metal, such as nickel-titanium tubing or stainless steel tubing.

[0057] In this embodiment, the support strength of the first covering 104 is greater than that of the second covering 202. The first covering 104 is made of PET membrane, and the second covering 202 is made of ePTFE membrane. PET membrane has high tensile strength, while ePTFE membrane has lower tensile strength, a smooth surface, and is less prone to thrombosis. It has good long-term patency for small blood vessels and has small pores. Combining PET membrane and ePTFE membrane ensures the overall strength of the stent covering and gives the covered stent 100 a better effect in isolating blood flow, ensuring long-term patency of branches and good occlusion effect. The fact that the support strength of the first covering 104 is greater than that of the second covering 202 makes the support strength of the covered portion of the external iliac channel 1022 greater than that of the embedded stent 20 of the internal iliac channel 1021. This makes the embedded stent 20 more easily deformable than the portion of the external iliac channel 1022, and thus more easily deformable along with the portion of the internal iliac channel 1021.

[0058] In this embodiment, to make the covered stent 100 easier to compress and have a smaller compressed folding volume when installed in the delivery device, the proximal support coil 1011, the distal support coil 1031, and the first coil 1023 can be sutured to the surface of the first covered stent by suturing. Specifically, during suturing, at least the peaks of the proximal support coil 1011, the distal support coil 1031, and the first coil 1023 in the proximal direction are not sutured to the first covered stent. Thus, when the covered stent 100 is folded and compressed, since the peak positions are not restricted by sutures, other suture points can undergo slight displacement to adapt to the folding of the covered stent and the deformation of the stent coils, thereby making the covered stent fold better. Furthermore, the unsutured peaks can reduce the suture ratio of the covered stent, so the covered stent can have better flexibility to adapt to blood vessels with more complex curvature.

[0059] In this embodiment, please refer to Figure 2 The aneurysm segment 102 includes a plurality of first wave coils 1023 spaced apart along the axial direction. The first wave coils 1023 are also Z-shaped annular wave coils. In order to maintain good flexibility of the aneurysm segment 102, the wave number of the plurality of first wave coils 1023 is the same, and the peaks and / or troughs of adjacent first wave coils 1023 are arranged opposite each other. Here, the same wave number and the peaks and / or troughs are arranged opposite each other, that is, adjacent first wave coils 1023 are arranged almost parallel to each other, so that there is a uniform spacing between adjacent first wave coils 1023. They are connected only by a membrane, so the flexibility is good and it is beneficial for the aneurysm segment 102 to better conform to the tortuous shape of the blood vessel. Preferably, the wave number of the first wave coils 1023 can also be equal to the wave number of the proximal support wave coil 1011, and the peaks and / or troughs are arranged opposite each other, so that the connection between the aneurysm segment 102 and the proximal segment 101 and the connection between the aneurysm segment 102 and the proximal segment 101 can also maintain good flexibility.

[0060] In this embodiment, please refer to Figure 4 and Figure 5 To ensure that the total support strength of the internal iliac channel 1021 and the embedded stent 20 is less than that of the external iliac channel 1022, the wave angle (angle a in the figure) of the same first wave loop 1023 of the aneurysm segment 102 located in the external iliac channel 1022 is greater than the wave angle (angle b in the figure) of the same first wave loop 1023 located in the internal iliac channel 1021. This is because when the wave loop deforms, the force required for deformation is greater than that for the wave loop with a smaller wave angle, so the support strength is also greater than that for the wave loop with a smaller wave angle. In some embodiments, to differentiate the wave angles, adjacent first wave loops 1023 with the same wave number and their peaks and / or troughs are set opposite each other, so that the wave height of the wave located in the external iliac channel 1022 is less than the wave height of the wave located in the internal iliac channel 1021, and the wave angle (angle d in the figure) of the wave located in the external iliac channel 1022 is greater than the wave angle (angle c in the figure) of the wave located in the internal iliac channel 1021. In another embodiment, the wave height of all waveforms in the first wave loop 1023 can be made to gradually increase from the external iliac channel 1022 portion to the internal iliac channel 1021 portion, and the wave angle can be made to gradually decrease, forming a structure with gradually decreasing support strength. In this way, the gradual decrease in support strength can avoid the sudden formation of a large support strength difference in the aneurysm segment 102 at the junction of the external iliac channel 1022 portion and the internal iliac channel 1021 portion, thereby preventing unpredictable and undesirable deformation of the aneurysm segment 102 at that position.

[0061] In other embodiments, please refer to Figure 6 To ensure that the total support strength of the internal iliac channel 1021 and the embedded stent 20 is less than that of the external iliac channel 1022, the wire diameter R1 of the first wave loop 1023 located in the external iliac channel 1022 can be larger than the wire diameter R2 of the first wave loop 1023 located in the internal iliac channel 1021. A larger wire diameter requires more force to resist the stiffness of the material itself during deformation. Therefore, under the same stress, the deformation of the wave loop with a larger wire diameter is less than that of the wave loop with a smaller wire diameter, thus providing stronger support. Strength; In some embodiments, braided filaments with small diameter and braided filaments with large diameter can be connected together by means of connectors or fasteners, and after connection, they are placed in the internal iliac channel 1021 part and the external iliac channel 1022 part of the tumor cavity segment 102 respectively; Alternatively, the first wave loop 1023 can be integrally cut and formed, and its filament diameter can be reduced in the internal iliac channel 1021 part by means of chemical corrosion, physical polishing, etc., or the filament diameter of the first wave loop 1023 can have a gradually decreasing tapered structure from the external iliac channel 1022 part to the internal iliac channel 1021 part.

[0062] To ensure that the support strength of the internal iliac passage 1021 portion of the embedded stent 20 and the aneurysm segment 102 is less than that of the external iliac passage 1022 portion, the embedded stent 20 is woven from metal braided wires with a smaller diameter. In this embodiment, the wire diameter d of the embedded stent 20 is less than half the wire diameter D of the first loop 1023 of the external iliac passage 1022 portion, that is, d is less than half of D, and the wire diameter M of the first loop 1023 of the internal iliac passage 1021 portion is also less than that of the first loop 1023 of the external iliac passage 1022 portion. The wire diameter is half of D, which ensures that the sum of the support strength of the embedded stent 20 and the internal iliac channel 1021 is always less than that of the external iliac channel 1022. However, the wire diameter of the first coil 1023 of the embedded stent 20 and the internal iliac channel 1021 is not limited to the above setting. Technicians can adjust the wire diameter of the embedded stent 20 and the first coil 1023 of the internal iliac channel 1021 according to the actual stent requirements to ensure that the sum of their support strength is less than that of the external iliac channel 1022.

[0063] In this embodiment, the support strength of the proximal and / or distal ends of the aneurysm segment 102 can be greater than that of the intermediate position. In one embodiment, the support strength of the first wave ring 1023 at the proximal and distal ends of the aneurysm segment 102 is greater than that of the first wave ring 1023 at the intermediate position. This is because, when a blood vessel forms an aneurysm, the junction between the aneurysm and the normal blood vessel is usually a location of severe compression. Setting the first wave ring 1023 at the proximal and distal ends of the aneurysm segment 102 to have higher support strength can better resist compression from the junction of the blood vessel and the aneurysm. Further... Setting the middle position to a lower support strength allows the aneurysm segment 102 to have a certain degree of flexibility and better adapt to the shape of the blood vessel. In other embodiments, the support strength of the first wave coil 1023 located at the proximal end of the aneurysm segment 102 can be set to be greater than the support strength of the first wave coil 1023 located at the middle position. This can at least ensure the support strength of the stent located at the blood inflow position. In order to achieve the above-mentioned change in support strength, the wire diameter or wave angle of the first wave coil 1023 at the proximal end of the aneurysm segment 102 can be made greater than the wire diameter or wave angle of the first wave coil 1023 located at the middle position.

[0064] In this embodiment, the support strength is specifically manifested as the deformation of the entire tubular cavity (internal iliac canal 1021 and external iliac canal 1022) of the covered stent 100 after being compressed in the aneurysm segment 102. That is, under the same stress conditions, the same force (which needs to cause deformation in both the internal iliac canal 1021 and external iliac canal 1022) is applied to compress the outer walls of the internal iliac canal 1021 and external iliac canal 1022, and the radial cross-sectional area of ​​the internal iliac canal 1021 and external iliac canal 1022 after compression is measured and calculated. Here, the support with a larger total cross-sectional area measured after compression has greater support strength, while the support with a smaller total cross-sectional area has less support strength. In some embodiments, the independently separated internal iliac channel 1021 and external iliac channel 1022 can be compressed separately using a flat plate force gauge. When the same amount of deformation is compressed, the force required is measured. The larger the force measured, the greater the support strength, and the smaller the force measured, the less the support strength. In this embodiment, the force measured in the external iliac channel 1022 is always greater than the force measured in the internal iliac channel 1021.

[0065] Example 2:

[0066] In this embodiment, please refer to Figures 7-9 The structure of the main support 10 and the embedded support 20 is largely the same as in Embodiment 1, except that the first wave ring 1023 includes multiple first wave rods 10232, which are connected end-to-end at an angle to form a Z-shaped or M-shaped annular wave ring. A support member 10233 is provided between adjacent first wave rods 10232. The support member 10233 is connected to the first covering 104 between two adjacent first wave rods 10232 by stitching or bonding. When two adjacent first wave rods 10232 are deformed by compressive force, the two first wave rods 10232 move closer to each other around their wave angle in a compressive motion. When they move to the position of the support member 10233, the two sides of the support member 10233... The first wave ring 1023 is supported by two first wave rods 10232 on each side, preventing the two first wave rods 10232 from continuing to move and compress, thus limiting the degree of deformation of the waveform and providing support. In order to make the support strength of the first wave ring 1023 in the external iliac channel 1022 section greater than the support strength in the internal iliac channel 1021 section, the multiple support members 10233 are configured such that the compressible distance between the first wave rods 10232 in the external iliac channel 1022 section is smaller than the compressible distance between the first wave rods 10232 in the internal iliac channel 1021 section. This is because if the compressible distance between two adjacent first wave rods 10232 is smaller, the degree of deformation of the waveform is reduced, and the support performance of the first wave ring 1023 at that waveform position is better.

[0067] Please see Figure 7 and Figure 8 In one embodiment, to achieve the above-mentioned effect, a gap 10234 can be provided between the support member 10233 and the adjacent first wave rod 10232. The purpose of providing the gap 10234 is to allow for movable deformation space between the first wave rod 10232 and the support member 10233. The larger the space, the larger the gap 10234, the greater the degree of waveform deformation, and the lower the support strength; conversely, the smaller the gap 10234, the smaller the degree of waveform deformation, and the higher the support strength. Therefore, by setting the gap 10234 between the support member 10233 of the external iliac channel 1022 and the adjacent first wave rod 10232 smaller than that of the internal iliac channel 1021, the gap 10234 is made smaller. The gap 10234 between the support member 10233 and the adjacent first wave rod 10232 enables the first wave ring 1023 to obtain greater support strength in the external iliac canal 1022 section than in the internal iliac canal 1021 section. With this configuration, when the first wave ring 1023 is subjected to compressive force, the first wave rods 10232 deform relatively close to each other. When the first wave rod 10232 located in the external iliac canal 1022 section abuts against the support member 10233, the first wave rod 10232 located in the internal iliac canal 1021 section can still continue to deform, so that the deformation of the aneurysm segment 102 in the internal iliac canal 1021 section is greater than the deformation in the external iliac canal 1022 section.

[0068] Please refer to Figure 7 and Figure 8 The support member 10233 can be a straight structure with two ends. To prevent the two ends of the straight structure support member 10233 from puncturing the membrane and scratching the blood vessels, the two ends can be bent into rings or formed into anti-damage heads, etc., as not shown in the figure. It can be understood that multiple straight structure support members 10233 can be support members 10233 of the same length, respectively located at different axial positions between adjacent first wave rods 10232. For example, in the external iliac canal 1022, support members 10233 of the same length are located near the wave angle to provide a smaller gap 10234. It can also be understood that multiple straight structure support members 10233 can be support members 10233 of different lengths, respectively located at the same axial position between adjacent first wave rods 10232. For example, the length of the support member 10233 in the external iliac canal 1022 is greater than the length of the support member 10233 in the internal iliac canal 1021 to provide a smaller gap 10234.

[0069] In another embodiment, please refer to Figure 9The support member 10233 is an elastic support member 10235, wherein both sides of the elastic support member 10235 are connected to the adjacent first wave rods 10232 respectively. With this configuration, the degree of deformation between two adjacent first wave rods 10232 is determined by the elastic deformation degree of the elastic support member 10235. When the elastic deformation degree of the elastic support member 10235 is large, that is, when the elastic modulus is small, the degree of deformation between the two adjacent first wave rods 10232 is large, and the support strength provided is low; conversely, when the elastic deformation degree of the elastic support member 10235 is large, the degree of deformation between the two adjacent first wave rods 10232 is small, and the support strength provided is low. When the deformation is small, that is, when the elastic modulus is large, the deformation between two adjacent first wave rods 10232 is small, and the support strength provided is large. Thus, by setting the elastic modulus of the elastic support member 10235 in the external iliac channel 1022 part to be greater than the elastic modulus of the elastic support member 10235 in the internal iliac channel 1021 part, the elastic support member 10235 with a larger elastic modulus provides greater support force in the external iliac channel 1022 part, and conversely, the elastic support member 10235 with a smaller elastic modulus provides less support force in the internal iliac channel 1021 part.

[0070] In some embodiments, the elastic support 10235 can be a spring structure, with both sides of the spring structure connected to the first wave rods 10232 on both sides respectively. The elastic modulus of the spring structure in the external iliac channel 1022 portion is set to be greater than the elastic modulus of the spring structure in the internal iliac channel 1021 portion.

[0071] In other embodiments, please refer to Figure 9 The elastic support 10235 can be an elastic connector with a spring in the middle and connecting structures on both sides. The deformation distance of the first wave rods 10232 on both sides can be limited by setting the total length of the middle spring. For example, the length of the spring in the elastic connector of the external iliac channel 1022 is set to be less than the length of the spring in the elastic connector of the internal iliac channel 1021. The shorter spring can provide less deformation than the longer spring. Thus, under the same force, the shorter spring reaches the deformation limit first compared to the longer spring, providing stable support force.

[0072] In other embodiments, please refer to Figure 10 By making the axial length of the portion of the aneurysm cavity 102 located in the internal iliac channel 1021 and the portion of the embedded stent 20 smaller than the axial length of the portion of the external iliac channel 1022, the support position of the aneurysm cavity 1021 when it is compressed in the radial direction is reduced, and the area that can withstand pressure is smaller; thus, the support strength of the aneurysm cavity 102 located in the internal iliac channel 1021 is less than the support strength of the external iliac channel 1022.

[0073] In some embodiments, please refer to Figure 10The distal port and opening 1024 of the embedded stent 20 can be set as bevels, and the bevels are directed away from the external iliac channel 1022. Furthermore, the bevel setting can make the selection entrance for the internal iliac stent 20 larger and reduce the difficulty of selection. The proximal port of the embedded stent 20 is also set as a bevel to increase the receiving area for blood inflow.

[0074] In one embodiment, the support member 10233 is at least partially provided with a developing structure (not shown in the figure). When the support member 10233 is provided with a developing structure, the shape of the support member 10233 can be set to a shape and structure with marking and identification function as required, such as a letter-shaped support member 10233 or a number-shaped support member 10233. The support member 10233 can also be entirely a developing structure. The preferred developing structure can be tantalum wire or gold wire.

[0075] Example 3

[0076] In this embodiment, please refer to Figure 11 and Figure 12 The structure of the main support 10 and the embedded support 20 is largely the same as in Embodiment 1. The difference is that the first wave 1023 has a break 10231 at least in the internal iliac channel 1021. It can be understood that the first wave 1023 has a break 10231 to form a C-shaped wave 1026. At the position of the break 10231, the first wave 1023 does not provide support. The position of the break 10231 is set in the internal iliac channel 1021, so that the aneurysm segment 102 is only covered by a membrane in the internal iliac channel 1021 without the support of the first wave 1023. The support force of the internal iliac channel 1021 is provided by the embedded support 20. However, the support strength of the embedded support 20 is lower than the support strength of the first wave 1023, so that the support strength of the aneurysm segment 102 in the internal iliac channel 1021 is less than the support strength in the external iliac channel 1022.

[0077] In one embodiment, the break 10231 only covers the position where the embedded stent 20 connects to the membrane of the aneurysm segment 102. The two ends of the C-shaped wave 1026 are connected to the two sides of the connection position between the embedded stent 20 and the membrane of the aneurysm segment 102. That is, the part of the internal iliac channel 1021 of the aneurysm segment 102 that is connected to the embedded stent 20 does not have the support provided by the first wave 1023. With this configuration, when the aneurysm segment 102 is subjected to compressive force, the part of the internal iliac channel 1021 connected to the embedded stent 20 will deform preferentially due to the lower support strength, thereby effectively avoiding excessive impact of compression on the shape of the external iliac channel 1022.

[0078] Please refer to further information. Figure 20The C-shaped coil 1026 is located at both ends of the break 10231 and wraps back to form a ring structure 10261 or a damage-preventing end. The ring structure 10261 can accommodate the end of the metal wire that is braided into the C-shaped coil 1026, thereby preventing the sharp end from piercing the membrane and scratching the blood vessels.

[0079] Example 4

[0080] In this embodiment, please refer to Figure 13 The structure of the main stent 10 and the embedded stent 20 is largely the same as in Embodiment 1, except that the embedded stent 20 in the aneurysm cavity segment 102 includes a first embedded stent 21 and a second embedded stent 22 arranged radially, wherein the first embedded stent 21 communicates with the distal segment 103; the distal end of the aneurysm cavity segment 102 is provided with an opening 1024, and the distal end of the second embedded stent 22 communicates with the opening 1024; wherein the aneurysm cavity segment 102 includes an internal iliac channel 1021 and an external iliac channel 1022, the external iliac channel 1022 receiving the first embedded stent 21, and the internal iliac channel 1021 receiving the second embedded stent 22;

[0081] The external iliac passage 1022 and the internal iliac passage 1021 are separated by an embedded first stent 21 and a second stent 22 to form a blood flow cavity. The first stent 21 and the second stent 22 can provide support to maintain the passage shape and prevent compression occlusion. The first stent 21 in the external iliac passage 1022 provides a supporting force that counteracts the force of the second stent 22 in the internal iliac passage 1021 during compression, thus enabling the covered stent 100 of this application to accommodate the implantation of the internal iliac stent. The internal iliac channel 1021 provides a well-formed passage while avoiding excessive compression of the external iliac channel 1022, which could lead to occlusion of the external iliac channel 1022. This allows for better maintenance of the overall shape and patency of the two channels. The blood inlet and outlet of the aneurysm cavity segment 102 at the proximal end of the segment 101 are occupied by the proximal and distal ports of the first embedded stent 21 and the second embedded stent 22, respectively. This ensures that when blood flows from the proximal end of the segment 101 into the aneurysm cavity segment 102, it is diverted by the first embedded stent 21 and the second embedded stent 22.

[0082] In this embodiment, please refer to Figures 14-16To ensure the proper deployment of the external iliac passage 1022 and guarantee its blood flow patency during compression of the aneurysm segment 102 or stent deployment, this application sets the support strength of the portion of the covered stent 100 located within the external iliac passage 1022 to be greater than the support strength of the portion located within the internal iliac passage 1021. In other words, this can be achieved by setting the support strength of the first embedded stent 21 to be greater than the support strength of the second embedded stent 22, provided that the support strength of the first embedded stent 21 is uniform; or by setting the support strength of the first embedded stent 21 equal to the support strength of the second embedded stent 22, thereby ensuring that the support strength of the external iliac passage 1022 of the aneurysm segment 102 is greater than the support strength of the internal iliac passage 1021; or by setting the support strength of the first embedded stent 21 to be greater than the support strength of the second embedded stent 22, and the support strength of the external iliac passage 1022 of the aneurysm segment 102 to be greater than the support strength of the internal iliac passage 1021.

[0083] In this embodiment, please refer to Figure 14 and Figure 15 Both the first embedded stent 21 and the second embedded stent 22 have a mesh body 201 and a second surface covering 202. The aneurysm cavity segment 102 of the main stent 10 includes multiple first corrugations 1023 spaced apart along the axial direction. The mesh body 201 provides better extensibility, allowing the second surface covering 202 of the first embedded stent 21 and the second embedded stent 22 to be opened more smoothly, preventing local compression and collapse. At the same time, it can provide more support points to abut against the internal iliac stent during implantation, increasing friction. By adjusting the wire diameter of the first embedded stent 21 and the second embedded stent 22... And by adjusting the wire diameter of the first wave loop 1023 located in the external iliac channel 1022 and the wire diameter of the first wave loop 1023 located in the internal iliac channel 1021, the portion of the covered stent 100 located in the aneurysm segment 102 of the internal iliac channel 1021 and the portion of the external iliac channel 1022 can have a difference in support strength. It is understood that a larger stent wire diameter can provide higher support performance. Therefore, by making the wire diameter of the first embedded stent 21 larger than the wire diameter of the second embedded stent 22, and / or the wire diameter of the first wave loop 1023 located in the external iliac channel 1022 larger than the wire diameter of the first wave loop 1023 located in the internal iliac channel 1021;

[0084] Please see Figure 14This causes the wire diameter of the first embedded stent 21 to be larger than that of the second embedded stent 22, and the wire diameter of the first wave loop 1023 located in the external iliac channel 1022 to be larger than that located in the internal iliac channel 1021. Because the wire diameter of the first wave loop 1023 in the internal iliac channel 1021 is smaller, when the aneurysm segment 102 is subjected to compressive force, the first wave loop 1023 in the internal iliac channel 1021 deforms preferentially over the first wave loop 1023 in the external iliac channel 1022, thus preferentially affecting the deformation of the second embedded stent 22 located within the internal iliac channel 1021. Since the wire diameter of the second embedded stent 22 is smaller than that of the first embedded stent 22, the deformation of the second embedded stent 22 is significantly reduced. An embedded stent 21 makes the deformation of the second embedded stent 22 better than that of the first embedded stent 21, distributing the support strength on the single-layer stent to the inner and outer stents. This prevents the support strength on a single stent from being too large. Furthermore, by reducing the wire diameter of the first coil 1023 of the internal iliac channel 1021 in the aneurysm segment 102 and the second internal iliac stent, it is possible to avoid a large difference in wire diameter on a single stent. The wire diameters of the two stents are not reduced too much, thus avoiding the problems of the stent being unable to maintain the support effect due to the wire diameter setting being too small and the flexibility being poor due to the wire diameter being too large.

[0085] Implementation Five

[0086] In this embodiment, please refer to Figure 16 The structure of the main stent 10 and the embedded stent 20 is largely the same as that in Embodiments 1 and 4. The difference is that in this embodiment, by making the mesh density of the first embedded stent 21 greater than that of the second embedded stent 22, the support strength of the portion of the aneurysm segment 102 of the covered stent 100 located in the external iliac channel 1022 is set to be greater than that of the portion located in the internal iliac channel 1021. Specifically, the first embedded stent 21 and the second embedded stent 22 include a mesh body 201. The mesh body 201 has multiple mesh structures. The higher the mesh density, the more braided filaments are required, and the smaller the area of ​​a single mesh, the greater the pressure it can withstand. A larger mesh density can provide greater support strength.

[0087] In this embodiment, please continue to refer to Figure 16The first embedded support 21 and the second embedded support 22 have a woven rhomboid mesh structure. The first embedded support 21 has a first rhomboid mesh, and the second embedded support 22 has a second rhomboid mesh. Both the first and second rhomboid meshes have an upper and a lower vertex in the axial direction and a left and a right vertex in the radial direction. The distance between the upper and lower vertices of the first rhomboid mesh is D1, and the distance between the left and right vertices is L1. The distance between the upper and lower vertices of the second rhomboid mesh is D2, and the distance between the left and right vertices is L2. Preferably, D1 and L1 can be smaller than D2 and L2, so that the area occupied by a single first rhomboid mesh is smaller than the area occupied by a single second rhomboid mesh. Therefore, under the same support unfolded area, the first embedded support 21 has a higher mesh density and provides stronger support strength than the second embedded support 22.

[0088] In another embodiment, please continue to refer to Figure 16 This allows the L1 of the first rhombus mesh to be at least smaller than the L2 of the second rhombus mesh, thereby changing the density of the first rhombus mesh only in the circumferential direction of the first embedded support 21. In this way, the density of the first rhombus mesh can be increased at least in the radial direction, thereby achieving the effect of enhanced support strength in the radial direction.

[0089] In one embodiment, the wave angle of the first wave loop 1023 of the aneurysm segment 102 located in the external iliac canal 1022 is greater than the wave angle of the first wave loop 1023 located in the internal iliac canal 1021. In another embodiment, the wave height of all waveforms of the first wave loop 1023 can be gradually increased from the external iliac canal 1022 to the internal iliac canal 1021, and the wave angle can be gradually decreased, forming a structure with gradually decreasing support strength. In this way, the gradual decrease in support strength can avoid the aneurysm segment 102 from suddenly forming a large support strength difference at the junction of the external iliac canal 1022 and the internal iliac canal 1021, thereby preventing unpredictable and undesirable deformation of the aneurysm segment 102 at that location. By simultaneously making the grid density of the first embedded stent 21 greater than that of the second embedded stent 22, and the wave angle of the first wave loop 1023 located in the external iliac channel 1022 greater than that located in the internal iliac channel 1021, and by setting variations in support strength on the first wave loop 1023 of the aneurysm segment 102 and on the first embedded stent 21 and the second embedded stent 22, the problem of poor stent flexibility at certain locations that might result from setting variations in support strength only on the first embedded stent 21 and the second embedded stent 22 or on the first wave loop 1023 of the aneurysm segment 102 can be avoided.

[0090] It is understandable that by making the grid density of the first embedded stent 21 greater than that of the second embedded stent 22, and / or making the wave angle of the first wave loop 1023 located in the external iliac channel 1022 greater than that of the first wave loop 1023 located in the internal iliac channel 1021, the support strength of the portion of the covered stent 100 located in the aneurysm cavity segment 102 in the external iliac channel 1022 can be set to be greater than that in the portion located in the internal iliac channel 1021.

[0091] Example 6

[0092] In this embodiment, please refer to Figures 17-19 The structure of the main support 10 and the embedded support 20 is largely the same as that in Embodiments 1 and 4-5, except that the internal iliac channel 1021 and the external iliac channel 1022 of the aneurysm cavity segment 102 are provided with different axial lengths. Figure 17 The axial length H2 of the aneurysm segment 102 in the internal iliac canal 1021 and external iliac canal 1022 is altered by H1 and H2. Specifically, the axial length H2 of the external iliac canal 1022 is greater than the axial length H1 of the internal iliac canal 1021. The aneurysm segment 102 has an axial length H2 in the external iliac canal 1022 and an axial length H1 in the internal iliac canal 1021. The greater length of H2 than H1 means that when the aneurysm segment 102 in the external iliac canal 1022 is compressed, the length and contact area that can withstand pressure are greater than the length and contact area that can withstand pressure in the internal iliac canal 1021. This results in better pressure dispersion, better support performance, and improved support strength. Please refer to further details. Figure 18 and Figure 19The distal end of the second embedded stent 22 includes an exposed segment 221, which extends from the opening 1024 and through the internal iliac channel 1021. This results in the internal iliac channel 1021 of the covered stent 100 having a distribution of different support strengths. At the intervention end of the internal iliac stent, only the second embedded stent 22 serves as a single-layer stent, providing good flexibility at this location and facilitating the selection of the internal iliac stent. Furthermore, the distal end of the exposed segment 221 is either flat or oblique. When set to a flat opening, the exposed segment 221 can have more attachment and support positions with the interventional internal iliac stent, thereby effectively improving the long-term stability of the internal iliac stent after intervention. When set to an oblique opening, the opening direction of the oblique opening is away from... The orientation of the external iliac passage 1022 allows for a wider selection portal for the internal iliac stent without increasing the diameter of the second embedded stent 22, making stent placement quicker and more convenient. The enlarged selection portal also improves the accuracy of stent placement. In some embodiments, the exposed segment 221 is abutted against the adjacent external iliac passage 1022. The exposed segment 221 can be a free end, allowing it to separate from the external iliac passage 1022. This arrangement prevents excessive pressure on the stent at this location after implantation, preventing compression kinking or occlusion. The exposed segment 221 can also be fixedly connected to the sidewall of the external iliac passage 1022 by suturing or adhesive bonding to prevent wobbling and facilitate better stent placement.

[0093] Please refer to Figures 18-19 Since the second embedded stent 22 protrudes through the opening 1024 of the aneurysm cavity segment 102, and there is only a single-layer stent at the opening 1024, the support is significantly weakened compared to other locations. To ensure that the aneurysm cavity segment 102 of the covered stent 100 of this application is more easily deformed at the internal iliac canal 1021 location than at the external iliac canal 1022 location when compressed, while avoiding compression and occlusion of the selected entrance of the exposed segment 221, the stent support of the portion of the external iliac canal 1022 near the exposed segment 221 is weakened. This can reduce the support of the external iliac canal 1022. The first wave 1023, which is at least located in the same axial position as the exposed segment 221, has a break 10231 to form a C-shaped wave 1026, and the break 10231 faces the exposed segment 221. With this arrangement, the support at the contact point between the external iliac channel 1022 and the exposed segment 221 is effectively weakened, so that when the internal iliac stent inlet of the exposed segment 221 is compressed, a certain amount of deformation can occur at the position where it abuts against the external iliac channel 1022, thereby buffering the compressive force and preventing the inlet from being further compressed.

[0094] Similar to Embodiment 3, the C-shaped coil 1026 is wound around the two ends of the break 10231 to form a ring structure. The ring structure can accommodate the ends of the metal wires that are braided into the C-shaped coil 1026, thereby preventing the sharp ends from piercing the membrane and scratching the blood vessels.

[0095] In this embodiment, please refer to Figure 20 To better adapt the covered stent 100 to the morphology of the diseased blood vessel, a proximal corrugation 1025 is provided at the proximal end of the aneurysm segment 102. The diameter of the proximal corrugation 1025 is set to be smaller than that of the distal end, giving the proximal corrugation 1025 an inclined angle, forming a stent structure that is narrower proximally and wider distally. Thus, the aneurysm segment 102 of the covered stent 100 forms a gradual transition structure from wide to narrow at the junction with the proximal segment 101, adapting to the diameter change from normal to diseased blood vessels, enhancing the anchorage between the proximal segment 101 and the blood vessel, and improving the stability of the covered stent 100 after implantation. In this embodiment... In order to ensure good passage through both the internal iliac channel 1021 and the external iliac channel 1022 of the aneurysm cavity segment 102, the radial dimension of the aneurysm cavity segment 102 is made larger than that of the proximal segment 101 and the distal segment 103. Furthermore, the placement of the first embedded stent 21 and the second embedded stent 22 ensures the blood flow through the internal iliac channel 1021 and the external iliac channel. The aneurysm cavity vessels also exhibit a size variation from large to small compared to the proximal vessels. Thus, the placement of the proximal wave loop can conform to the structure while enhancing the surface adhesion of the covered stent 100 of this application, preventing the stent from swinging within the vessel, and also preventing the stent from slipping and displacing within the vessel.

[0096] In other embodiments, please refer to Figure 21 The proximal and distal ports of the first embedded stent 21 and the second embedded stent 22 can be set as flat or oblique openings, respectively. For example, the proximal and distal ports of the second embedded stent 22 can be set as parallel oblique openings, and the proximal port of the first embedded stent 21 can be set as an oblique opening. This can further make the second embedded stent 22 form an unstable parallelogram structure, thereby having staggered support points in the radial direction. It is easy to deform under pressure to reduce the support strength. The oblique opening of the proximal ports of the first embedded stent 21 and the second embedded stent 22 can form a larger blood inlet to smoothly receive blood from the proximal segment.

[0097] In this embodiment, the surface of the main support 10 is covered with a first film 104, and the surfaces of the first embedded support 21 and the second embedded support 22 are covered with a second film 202. The support strength of the first film 104 is greater than that of the second film 202. The first film 104 is made of PET film, and the second film 202 is made of ePTFE film. The difference in support strength between the first film 104 and the second film 202 is mainly reflected in the properties of the materials themselves. The tensile strength of the PET film used in the first film 104 is typically between 50-200 MPa, exhibiting good impact resistance. Performance, while the tensile strength of the ePTFE membrane used in the second membrane 202 is usually between 23-30 MPa, and its impact resistance is poor; therefore, using the first membrane 104 and the second membrane 202 with different tensile strengths can make the main stent 10 and the first embedded stent 21 and the second embedded stent 22 have different support strengths at the membrane level, and better cooperate with the stent itself to set different support strengths; the purpose of using ePTFE membranes for the first embedded stent 21 and the second embedded stent 22 is to improve blood permeability while minimizing the impact of the membrane on the support strength.

[0098] In another embodiment, to better adapt the covered stent 100 provided in this application to the diseased iliac artery, the support strength of the distal segment 103 and the proximal segment 101 of the covered stent 100 is set to be greater than the total support strength of the aneurysm segment 102, the first embedded stent 21, and the second embedded stent 22. This is because the aneurysm segment 102 itself has support strength, and with the first embedded stent 21 and the second embedded stent 22 in place, the support strength at that location of the covered stent 100 is measured by the total support strength of the aneurysm segment 102, the first embedded stent 21, and the second embedded stent 22. Setting the support strength of the distal segment 103 and proximal segment 101 of the covered stent 100 to be greater than the total support strength of the aneurysm segment 102, the first embedded stent 21, and the second embedded stent 22 allows the covered stent 100 to have better support in both the proximal and distal vessels near the iliac artery lesion, improving the anchoring force between the stent and the vessel and firmly anchoring the covered stent 100 of this application in the release position. The purpose of weakening the support strength at the aneurysm segment 102 is to make it more flexible, thereby improving compliance and better conforming to the shape of the aneurysm segment 102 vessel, avoiding poor adhesion. In some other embodiments, the support strength of the distal segment 103 or the proximal segment 101 of the covered stent 100 is set to be greater than the total support strength of the aneurysm segment 102, the first embedded stent 21, and the second embedded stent 22; a larger support strength is set at either end of the proximal segment 101 or the distal segment 103 to ensure that, given the good flexibility of the aneurysm segment 102, at least one end has good support and anchoring performance to ensure the stability of the covered stent 100 when anchored in the blood vessel in vivo.

[0099] In some embodiments, this can be achieved by simultaneously reducing the support strength of the first embedded stent 21, the second embedded stent 22, and the aneurysm segment 102. For example, the overall support strength of the first embedded stent 21 and the second embedded stent 22 can be less than half the support strength of the proximal segment 101 or the distal segment 103, and the support strength of the aneurysm segment 102 can be less than half the support strength of the distal segment 103.

[0100] Example 7

[0101] In this embodiment, please refer to Figure 22 and Figure 23 The structure of the main stent 10 and the embedded stent is largely the same as in Embodiments 1 and 4-6. The difference is that the main stent 10 has supporting wave loops at the proximal segment 101 and distal segment 103, while the aneurysm cavity covering segment 102 does not have a first wave loop 1023, but is only covered with a membrane. The inner cavity of the aneurysm cavity covering segment 102 has a first embedded stent 21 and a second embedded stent 22, which provide support performance. The proximal segment 101, the aneurysm cavity covering segment 102, and the distal segment 103 of the main stent 10 can be connected by a first membrane 104. The surfaces of the proximal segment 101 and the distal segment 103 are provided with supporting wave loops, and the aneurysm cavity covering segment 102 is only covered with a membrane. Alternatively, the proximal segment 101 and the aneurysm cavity covering segment 102 can be connected by a single membrane, and the distal segment 103 can be connected to the distal end of the external iliac channel 1022 of the aneurysm cavity covering segment 102 by adhesion or suturing. Please refer to Figure 24 The first embedded stent 21 and the second embedded stent 22 include a mesh body 201. The purpose of setting the mesh body 201 is to emphasize better morphological support. Compared with the support coil, the mesh body 201 can have better covering tension, so even with a smaller braided wire diameter, it can still provide better covering tension to maintain the shape of the blood passage. The aneurysm cavity covering segment 102 only covers the covering. With the first embedded stent 21 and the second embedded stent 22 having a smaller wire diameter, the overall support strength of the covering stent 100 in the aneurysm cavity covering segment 102 is less than that of the proximal segment 101 and the distal segment 103. Thus, the aneurysm cavity covering segment 102 as a whole can maintain the shape and passage of the internal iliac channel 1021 and the external iliac channel 1022 while having better flexibility.

[0102] In this embodiment, please refer to Figures 23-26The first embedded stent 21 and the second embedded stent 22 are connected to the first covering 104 of the aneurysm cavity covering segment 102 by adhesive bonding or suturing, at least at their distal port and proximal port positions. The blood inlet at the proximal end and the blood outlet at the distal end of the aneurysm cavity covering segment 102 are both occupied by the proximal and distal ports of the first embedded stent 21 and the second embedded stent 22, so that when blood flows from the proximal segment 101 into the aneurysm cavity covering segment 102, it is diverted by the first embedded stent 21 and the second embedded stent 22, thereby avoiding endoleak in the aneurysm cavity covering segment 102. The proximal and distal ports of the first embedded stent 21 and the second embedded stent 22 can be set as flat or oblique openings.

[0103] Please see Figure 24 To improve blood flow and enhance the flexibility of the aneurysm cavity covered segment 102, the proximal ends of the first embedded stent 21 and the second embedded stent 22 are configured with bevels. Specifically, a first proximal bevel 211 is located at the proximal end of the first embedded stent 21, and a second proximal bevel 222 is located at the proximal end of the second embedded stent 22. The first proximal bevel 211 and the second proximal bevel 222 are positioned opposite each other, forming a V-shaped cross-section in the axial direction. This configuration, with its double bevels, increases the receiving area of ​​the blood inlet at the aneurysm cavity covered segment 102, allowing for smoother blood flow. Furthermore, the bevel configuration reduces the number of support points on both radial sides of the first embedded stent 21 and the second embedded stent 22, thereby reducing the radial support strength and ensuring the covered stent 100 is positioned within the aneurysm cavity covered segment 102. The support strength of segment 02 is less than that of proximal segment 101 and distal segment 103. Furthermore, when the stent is bent, the larger bend side is the extended portion, while the smaller bend side is the compressed portion. By setting the first proximal bevel 211 and the second proximal bevel 222 as a double bevel design with opposite orientations, when the covered stent 100 is bent, the larger bend side is on the side with the longer bevel extension of the first proximal bevel 211 or the second proximal bevel 222, and the smaller bend side is on the side with the shorter bevel extension. Therefore, when bending, the bevel structure of the first proximal bevel 211 and the second proximal bevel 222 conforms to the bending structure of the stent. The side with the longer bevel extension is on the larger bend side, and the side with the shorter bevel extension is on the smaller bend side. This makes the covered stent 100 more flexible, at least in the covered segment of the aneurysm cavity. When the covered stent 100 is bent, it can effectively prevent the bending of the embedded stent in the covered segment 102 of the aneurysm cavity.

[0104] In other embodiments, the provision of the first proximal bevel 211 and the second proximal bevel 222 allows the long axis sidewall and short axis sidewall of the first embedded bracket 21 and the second embedded bracket 22 to be misaligned. As a result, when the covered bracket 100 of this application is compressed and placed into the delivery sheath, the misaligned long axis sidewall and short axis sidewall can make the folded volume of the first embedded bracket 21 and the second embedded bracket 21 smaller and easier to put into the delivery sheath.

[0105] In this embodiment, please refer to Figure 24 and Figure 26 The distal end of the first embedded stent 21 is either oblique or flat, and the distal end of the second embedded stent 22 is also either oblique or flat. The distal blood outlet of the aneurysm cavity covering segment 102 is flush with and conforms to the distal ends of the first and second embedded stents 21 and is fixed by adhesion or suturing. The distal end of the second embedded stent 22 has a second distal oblique opening 223, and the distal end of the first embedded stent 21 has a first distal oblique opening 213 or a flat opening. Please refer to [link / reference]. Figure 26 When the distal ends of the first embedded stent 21 and the second embedded stent 22 are set as bevels, the first distal bevel 213 and the second distal bevel 223 are parallel to the first proximal bevel 211 and the second proximal bevel 222, respectively. Compared with a rectangle, the supporting force of the opposite sides of a non-rectangular parallelogram is less than the supporting force of the opposite sides of a rectangle. Thus, the parallel bevels can make the supporting positions of the first embedded stent 21 and the second embedded stent 22 on both radial sides form a staggered structure. Therefore, when subjected to radial extrusion force, part of the radial pressure will be converted into axial force by the special structure of the parallelogram, thereby effectively dispersing the radial pressure and reducing the radial supporting force. This makes the first embedded stent 21 and the second embedded stent 22 have better flexibility while providing tube shape retention force, thus making the aneurysm cavity covered section 102 of the covered stent 100 more flexible.

[0106] In another embodiment, please refer to Figure 24 The distal end of the second embedded stent 22 is a second distal bevel 223, and the distal end of the first embedded stent 21 is a first distal flat 212. This configuration allows the axial length H3 of the side of the first embedded stent 21 away from the second embedded stent 22 to be greater than the axial length H4 of the side of the second embedded stent 22 away from the first embedded stent 21. This results in the first embedded stent 21 having more stent support positions to disperse the compressive force from the blood vessel, thus providing better support strength compared to the second embedded stent 22.

[0107] Please see Figure 25When the distal end of the first embedded stent 21 is set as an oblique opening, the support wave ring at the connection position between the distal segment 103 and the aneurysm cavity is an inclined structure adapted to the first distal oblique opening 213, and is set as a triangular wave ring 1032, wherein the wave height on one side of the triangular wave ring 1032 is greater than the wave height on the other side and has a gradually decreasing structure, or a break is formed on the side with a low wave height.

[0108] In this embodiment, please refer to Figure 25 The covered stent 100 further includes a transition section 1027 connecting the proximal segment and the tumor cavity covered segment 102. When the proximal ports of the first embedded stent 21 and the second embedded stent 22 are set as double oblique openings, the transition section 1027 is located between the proximal end of the tumor cavity covered segment 102 and the first proximal oblique opening 211 and the second proximal oblique opening 222. The transition section 1027 is provided with a transition stent 10271, which can support the covered segment 1027 formed between the double oblique openings, thereby avoiding the lack of support structure at this position of the tumor cavity covered segment 102, which could lead to collapse or poor release.

[0109] In this embodiment, please refer to Figures 27-28 The transition stent 10271 is separately disposed on the transition section 1027, and the shape of the transition stent 10271 is adapted to the shape of the transition section 1027. Here, since the distal end of the support wave ring of the proximal section 101 near the tumor cavity covering section 102 is a flat opening with uniform wave height, and a V-shaped opening is formed between the first proximal oblique opening 211 and the second proximal oblique opening 222, in order for the transition stent 10271 to be flush with the proximal end of the tumor cavity covering section 102 and the first proximal oblique opening 211 and the second proximal oblique opening 222 at the proximal and distal ends respectively, the proximal end of the transition stent 10271 includes a flat opening, while the distal end includes a protruding V-shaped protrusion.

[0110] In some embodiments, the transition stent 10271 can be an annular stent or a separate sheet stent. When the transition stent 10271 is configured as an annular stent, at least two V-shaped protrusions are provided and symmetrically arranged on both sides of the annular stent to adapt to the V-shaped openings formed by the first proximal bevel 211 and the second proximal bevel 222. The annular stent can provide better overall support performance, providing support not only in the transition section 1027 region but also at the junction of the proximal section 101 and the tumor cavity covered section 102, so that the covered stent 100 provides support at the junction of the proximal section 101 and the tumor cavity covered section 102. The transition connection of the cavity covering segment 102 is more stable; when the transition stent 10271 is set as a separate sheet stent, at least two sheet stents are provided, which are symmetrically arranged on both sides of the V-shaped opening formed by the first proximal oblique opening 211 and the second proximal oblique opening 222, and the proximal side of the single sheet stent is flat, and the distal side is a V-shaped edge with a central protrusion and gradually decreasing sides; the single sheet stent directly provides support force on the transition segments 1027 on both sides, which can ensure that the transition segments 1027 are supported while making the proximal segment 101 and the cavity covering segment 102 have better flexibility.

[0111] In one embodiment, please refer to Figure 27 and Figure 28 The transition stent 10271 is a corrugated stent with a Z-shaped or W-shaped braided structure. The corrugated stent structure is similar to the proximal support corrugated stent 1011 of the proximal segment 101, which makes it better connected to the proximal segment 101 at this position, thereby improving the overall flexibility of the covered stent 100. In another embodiment, the transition stent 10271 is a mesh braided stent with a mesh braided structure. The structure of the mesh braided stent is similar to that of the first embedded stent 21 and the second embedded stent 22, which makes the overall integrity of the aneurysm cavity covered segment 102 higher, and the mesh braided stent has stronger supporting tension, making the inner wall smoother, which can further ensure the patency of blood flow at this position.

[0112] Example 8

[0113] In this embodiment, please refer to Figure 29 and Figure 30The structure of the main stent 10 and the embedded stent 20 is largely the same as in Embodiment 7, except that the transition stent 10271 is not set separately. Instead, a shaped wave loop 1012 is set at the distal end of the proximal segment 101. A portion of the shaped wave loop 1012 extends into the transition segment 102 within the tumor cavity covering segment 102 to form a support structure, thereby forming the transition stent 10271. Specifically, the proximal end of the shaped wave loop 1012 has a uniform, equal-height proximal wave 102711, and the distal end includes multiple distal waves with unequal heights. Wave 102712, the distal high wave 102712 protrudes distally, its apex flush with the first proximal bevel 211 and the second proximal bevel 222 of the first embedded support 21 and the second embedded support 22, to support the transition section 1027; the irregular wave loop 1012 has at least two distal high waves 102712, and the two distal high waves 102712 are symmetrically arranged on both sides of the distal end along the diameter of the irregular wave loop 1012, with the apexes of the two distal high waves 102712 close to the bottom of the V-shaped opening; please refer to further details. Figure 29 Multiple high-wavelength 102712 at the distal end of the irregular waveband 1012 can be provided. At the distal end of the irregular waveband 1012, a mountain-shaped structure with the highest wavelength in the middle and gradually decreasing wavelength towards both sides is formed to adapt to the shape of the transition section 1027. The support waveband at the distal end of the proximal section 101 is set as the irregular waveband 1012. This can avoid the transition section 1027 from lacking a support structure, which may lead to local collapse or poor release and affect blood flow. At the same time, the structure of the irregular waveband 1012 extending between the proximal section 101 and the aneurysm cavity covered section 102 can make the connection force of the covered stent 100 between the proximal section 101 and the aneurysm cavity covered section 102 stronger and the overall integrity of the stent higher, thereby avoiding bending at the transition position between the aneurysm cavity covered section 102 and the proximal section 101.

[0114] Example 9

[0115] In this embodiment, the structure of the main stent 10 and the embedded stent 20 is largely the same as that in embodiments seven and eight. The difference is that the distal segment 103 of the main stent 10 and the aneurysm cavity covering segment 102 are spliced ​​and fixed by adhesive or suturing. The surface of the main stent 10 is provided with a first covering 104, and the surface of the embedded stent 20 is provided with a second covering 202. The first covering 104 is a PET film, and the second covering 202 is an ePTFE film. The distal segment 103 and the aneurysm cavity covering segment 102 are spliced ​​together, which allows the surface covering of the distal segment 103 to also be made of ePTFE film, so as to further ensure the patency of blood flow in the external iliac vessels.

[0116] In one embodiment, the first embedded stent 21 and the distal segment 103 are integrally formed. The distal segment 103 extends directly into the tumor cavity covering segment 102 and is sutured to it. The portion of the external iliac passage 1022 located within the tumor cavity covering segment 102 forms the first embedded stent 21, and the portion located outside the tumor cavity covering segment 102 forms the distal segment 103. Thus, the stent body integrally formed by the first embedded stent 21 and the distal segment 103 can be a corrugated stent or a mesh braided stent, while the surface covering... The membrane is made of ePTFE. Here, "integrated molding" means that the first embedded stent 21 and the distal segment 103 are molded on the same ePTFE membrane, and the resulting overall stent does not have an adhesive structure or a suture structure. Integrating the first embedded stent 21 and the distal segment 103 into one piece allows blood to flow into the external iliac channel 1022 and towards the external iliac vessels without any obstructions or protrusions from splicing structures affecting the smoothness of the inner wall, which can effectively further improve the patency of blood flow.

[0117] In this embodiment, please refer to Figure 26 The proximal and / or distal ports of the first embedded stent 21 and the second embedded stent 22 are provided with imaging elements 203. The imaging elements 203 are provided at both the proximal and distal ports of the first embedded stent 21 and the second embedded stent 22. The imaging elements 203 can help the operator quickly locate the position of the tumor cavity covering segment 102, the relative position of the internal iliac channel 1021 and the external iliac channel 1022, and the morphological changes after compression using imaging equipment. It can also help the operator quickly locate the entry point of the internal iliac stent to achieve rapid and accurate implantation of the internal iliac stent.

[0118] In this embodiment, please refer to Figure 31To ensure that the covered stent 100 can be fine-tuned in its deployment position even after initial intravascular deployment if the position is inaccurate, multiple hooks 1013 are provided on the proximal segment 101 of the main stent 10. These hooks 1013 are arranged along the axial direction of the proximal segment 101, with at least two hooks 1013 at the same axial position. This allows two hooks 1013 at the same axial position to be pulled to the same position and hooked onto the hanging rod 30. Hooks 1013 at different axial positions are also hooked. After being attached to the hanging rod 30, at least a portion of the proximal segment 101 of the covered stent 100 can be at least partially constricted and bound, so that after the stent is initially released from the conduit of the delivery device, it is in a semi-bound state and not fully released. If the release position is not accurate at this time, the release position can be finely adjusted before the hanging rod 30 is pulled out to achieve complete release of the stent. The hook 1013 can be a ring-shaped hook made of polymer material, such as a ring-shaped thread made of PET material. It can be fixed to the proximal support wave 1011 of the proximal segment 101 or the covered film by sewing or bonding.

[0119] Example 10

[0120] In this embodiment, please refer to Figures 32-33 This invention provides a stent delivery system 1000, which includes a covered stent 100 as provided in Embodiments 1 to 9, and further includes a delivery device 200. The delivery device 200 is used to deliver the covered stent 100 to a designated vascular location and release it. The delivery device 200 typically includes a delivery sheath 2001 and a delivery handle 2002. The delivery handle 2002 is used to control the advance and retraction of the delivery sheath 2001 to release the stent from the delivery sheath 2001. Please refer to [link to relevant documentation]. Figure 31 The delivery sheath 2001 includes a hanging rod 30, which is used to hook the hook 1013 on the proximal segment 101 of the covered stent 100, so that at least the proximal segment 101 of the covered stent 100 is in a semi-bound state after hooking.

[0121] In this embodiment, the covered stent 100 has a pre-placed guidewire 40 in the internal iliac channel 1021 of at least the covered segment 102 of the aneurysm cavity. The pre-placed guidewire is placed in the covered stent 100 after the covered stent 100 is manufactured, so that when the stent is released, there is no need to reinsert the guidewire. By placing the pre-placed guidewire 40 in the internal iliac channel 1021 of the covered segment 102 of the aneurysm cavity, the operation of guidewire insertion and selection can be reduced. The internal iliac stent can be quickly guided to the first embedded stent 21 of the internal iliac channel 1021 for release directly through the guidance of the pre-placed guidewire 40, which improves the accuracy of release and reduces the operation time.

[0122] The above specific embodiments are only some embodiments of the present invention and are not intended to limit the present invention. This specification cannot exhaustively describe all embodiments of the present invention concept, and some features of the different embodiments described above can be substituted for or combined with each other. Those skilled in the art can also make simple substitutions according to actual needs. The concept of the present invention is subject to the claimed protection scope.

Claims

1. A covered stent, characterized by, The main body support includes a tubular main body, which includes an proximal end section, a tumor cavity section and a distal end section in the axial direction; the proximal end section communicates with the distal end section through the tumor cavity section; the tumor cavity section is provided with an internal iliac artery channel and an external iliac artery channel arranged in the radial direction, the external iliac artery channel is provided with a first embedded stent, the internal iliac artery channel is provided with a second embedded stent, and the first embedded stent communicates with the distal end section; the distal end of the tumor cavity section is provided with an opening communicating with the outside, and the distal end port of the second embedded stent communicates with the opening; the support strength of the first embedded stent and the external iliac artery channel is greater than the support strength of the second embedded stent and the internal iliac artery channel.

2. The stent graft of claim 1, wherein, The external iliac artery channel accommodates the first embedded stent, and the internal iliac artery channel accommodates the second embedded stent; the support strength of the first embedded stent is greater than the support strength of the second embedded stent, and / or the support strength of the external iliac artery channel is greater than the support strength of the internal iliac artery channel.

3. The stent graft of claim 2, wherein, The first embedded stent and the second embedded stent include a mesh main body, and the tumor cavity section includes a plurality of first wave coils arranged in the axial direction.

4. The stent graft of claim 3, wherein, The wire diameter of the first embedded stent is greater than the wire diameter of the second embedded stent, and / or the wire diameter of the first wave coil at the external iliac artery channel is greater than the wire diameter of the first wave coil at the internal iliac artery channel.

5. The stent graft of claim 3, wherein, The mesh density of the first embedded stent is greater than the mesh density of the second embedded stent, and / or the wave angle of the first wave coil at the external iliac artery channel is greater than the wave angle of the first wave coil at the internal iliac artery channel.

6. The stent graft of claim 3, wherein, The axial length of the external iliac artery channel is greater than the axial length of the internal iliac artery channel, and the distal end of the second embedded stent includes an exposed section which passes out of the opening.

7. The stent graft of claim 6, wherein, The external iliac artery channel is provided with a break at least at the first wave coil which is located at the same axial position as the exposed section, and the break is directed towards the exposed section.

8. The stent graft of claim 1, wherein, The proximal end of the tumor cavity section is provided with a transition wave coil, and the proximal end diameter of the transition wave coil is smaller than the distal end diameter thereof.

9. The stent graft of claim 1, wherein, The surface of the main body support is covered with a first coating film, the surface of the first embedded stent and the second embedded stent is covered with a second coating film, and the support strength of the first coating film is greater than the support strength of the second coating film.

10. The stent graft of any one of claims 1-9, wherein, The support strength of the distal end section and the proximal end section is greater than the total support strength of the tumor cavity section, the first embedded stent and the second embedded stent.

11. The stent graft of any one of claims 1-9, wherein, The support strength of the distal end section or the proximal end section is greater than the total support strength of the tumor cavity section, the first embedded stent and the second embedded stent.

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