Covered stent and delivery system

Abstract

Provided in the present invention are a covered stent and a delivery system. The covered stent comprises a main stent having a tubular main body and an embedded stent. The main stent comprises a proximal section, an aneurysm sac section and a distal section in the axial direction. The aneurysm sac section comprises a first channel and a second channel which are arranged in the radial direction, the second channel communicating with the distal section, and the first channel being provided with an opening at the distal end and being internally provided with the embedded stent. The provision of the embedded stent provides a channel for implantation of an internal iliac artery stent, so as to enable the internal iliac artery stent to have better anchoring performance, wherein the total scaffolding strength of the first channel and the embedded stent is smaller than that of the second channel, and since the second channel has the higher scaffolding strength, the first channel deforms before the second channel when the covered stent is subjected to compression, so as to enable the second channel to keep a better channel form, thereby preventing compression-induced occlusion and ensuring blood to smoothly pass through the second channel.

Description

Stent graft and delivery system Technical Field

[0001] The present invention relates to the technical field of medical devices, and in particular to a stent graft and a delivery system. Background Art

[0002] The iliac arteries include the common iliac arteries, external iliac arteries and internal iliac arteries; in the treatment of iliac aneurysm diseases, the existing technology can use intravascular therapy to implant an iliac artery bifurcation stent and an internal iliac covered stent to reconstruct the arterial blood vessels. The iliac artery bifurcation stent in the existing technology usually has two branch channels, which are used to reconstruct the internal iliac artery and the external iliac artery respectively. In order to ensure that the internal iliac artery channel is not blocked by blood vessel compression, the waveform design of the internal iliac artery channel will provide a certain support strength. In fact, the blood flow patency of the external iliac artery channel is far more important than the blood flow patency of the internal iliac artery channel. Therefore, the external iliac artery generally ensures the patency of blood flow by designing a larger lumen. However, if the lumen of the external iliac artery channel is too large, it will place higher requirements on the patient's vascular anatomy, which is not conducive to expanding the scope of application of the device. Summary of the Invention

[0003] Based on this, it is necessary to provide a new covered stent that can provide an internal iliac stent implantation channel and, when the stent is compressed, can provide the external iliac pathway with better support strength to maintain the overall shape of the external iliac pathway.

[0004] A coated stent comprises a main stent with a tubular body and an embedded stent, the main stent comprising a proximal segment, a tumor cavity segment and a distal segment along the axial direction; the proximal segment is connected to the distal segment through the tumor cavity segment; the tumor cavity segment comprises a first channel and a second channel arranged along the radial direction, the second channel is connected to the distal segment, and the distal end of the first channel is provided with an opening connected to the outside world; the embedded stent is arranged in the first channel, the embedded stent is at least partially connected to the side wall of the first channel, and the distal end of the embedded stent is connected to the opening; the total support strength of the first channel and the embedded stent is less than the support strength of the second channel.

[0005] In one embodiment, the tumor cavity segment includes a plurality of first wave coils spaced apart along the axial direction, the plurality of first wave coils have the same wave number, and the crests and / or troughs of adjacent first wave coils are arranged relative to each other.

[0006] In one embodiment, at least a portion of the first wave coil located in the first channel is provided with a break.

[0007] In one embodiment, the wave angle of the first wave coil in the second channel portion is greater than the wave angle of the same first wave coil in the first channel portion, or the wire diameter of the first wave coil in the second channel portion is greater than the wire diameter of the same first wave coil in the first channel portion.

[0008] In one embodiment, the first wave ring includes a plurality of first wave rods, and support members are provided between adjacent first wave rods, and the plurality of support members are configured to make the compressible distance between the first wave rods at the second channel portion smaller than the compressible distance between the first wave rods at the first channel portion.

[0009] In one embodiment, a gap is provided between the support member and the adjacent first wave rod, and the gap at the second channel portion is smaller than the gap at the first channel portion.

[0010] In one embodiment, the support member is an elastic support member, both sides of which are respectively connected to two adjacent first wave rods, and the elastic modulus of the elastic support member at the second channel portion is greater than the elastic modulus of the elastic support member at the first channel portion.

[0011] In one embodiment, the proximal segment includes a plurality of proximal support waves spaced apart in the axial direction, the distal segment includes a plurality of distal support waves spaced apart in the axial direction, and the embedded stent includes a mesh body.

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

[0013] In one embodiment, the support strength of the tumor cavity segment at the proximal and distal ends is greater than the support strength at the middle position.

[0014] In one embodiment, the support strength of the tumor cavity segment at the proximal or distal end is greater than the support strength at the middle position.

[0015] The beneficial effects of the present invention are as follows: compared with the prior art, the present invention provides a coated stent, comprising a main stent with a tubular body and an embedded stent, the main stent including a proximal segment, a tumor cavity segment and a distal segment along the axial direction; the tumor cavity segment includes a first channel and a second channel arranged along the radial direction, the second channel is connected to the distal segment, the distal end of the first channel is provided with an opening and an embedded stent is arranged therein, and the embedded stent is provided to provide an implantation channel for the internal iliac stent, so that the internal iliac stent has better anchoring properties; wherein, the total support strength of the first channel and the embedded stent is less than the support strength of the second channel, and the second channel has a higher support strength so that when the coated stent is under pressure, the first channel part deforms first than the second channel part, so that the second channel part can maintain a better channel shape, avoid pressure occlusion, and ensure that blood passes smoothly in the second channel part. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] FIG1 is a schematic diagram of the overall structure of a stent graft in Example 1 of the present invention;

[0017] FIG2 is a schematic diagram of the main support structure in Example 1 of the present invention;

[0018] FIG3 is a schematic diagram of the structure of the embedded bracket in Example 1 of the present invention;

[0019] FIG4 is a schematic diagram of the wave angle distribution structure of the first wave ring in Example 1 of the present invention;

[0020] FIG5 is a schematic diagram of a first wave coil with tapered wave angles in accordance with a first embodiment of the present invention;

[0021] FIG6 is a schematic diagram of the wire diameter distribution structure of the first corrugated coil in Example 1 of the present invention;

[0022] FIG7 is a schematic diagram of the structure of support members of different lengths for the first wave coil in Example 2 of the present invention;

[0023] FIG8 is a schematic diagram of the structure of the support members of different heights of the first wave ring in the second embodiment of the present invention;

[0024] FIG9 is a schematic structural diagram of a second embodiment of the present invention when the supporting member is an elastic supporting member;

[0025] FIG10 is a schematic structural diagram of a stent graft in another embodiment of the second embodiment of the present invention;

[0026] FIG11 is a schematic diagram of the structure of the main support in Example 3 of the present invention;

[0027] FIG12 is a schematic diagram of a structure in which a first wave coil is provided with a fracture in a third embodiment of the present invention;

[0028] FIG13 is a schematic diagram of the overall structure of the stent graft in Example 4 of the present invention;

[0029] FIG14 is a schematic diagram of the structure of the first embedded stent and the second embedded stent with different wire diameters in Example 4 of the present invention;

[0030] FIG15 is a partial enlarged schematic diagram of position A in FIG14 of the present invention;

[0031] FIG16 is a schematic diagram of a structure of different mesh densities of a first embedded bracket and a second embedded bracket in Example 5 of the present invention;

[0032] FIG17 is a schematic diagram showing that the first channel and the second channel of the tumor cavity segment in Example 6 of the present invention have different axial lengths.

[0033] FIG18 is a schematic diagram of the flat-end structure of the exposed section of the second embedded bracket in Example 6 of the present invention;

[0034] FIG19 is a schematic diagram of the oblique structure of the exposed section of the second embedded bracket in Example 6 of the present invention;

[0035] FIG20 is a schematic diagram of a structure in which a variable-diameter proximal wave ring is provided at the proximal end of the tumor cavity segment in Example 6 of the present invention;

[0036] FIG21 is a schematic diagram of another stent graft structure in Example 6 of the present invention;

[0037] FIG22 is a schematic diagram of the structure of the stent graft in Example 7 of the present invention;

[0038] FIG23 is a schematic diagram of the main support structure in Example 7 of the present invention;

[0039] FIG24 is a schematic diagram of different axial lengths of the first embedded stent and the second embedded stent in Example 7 of the present invention;

[0040] FIG25 is a schematic diagram of the structure of a triangular wave coil support in Example 7 of the present invention;

[0041] FIG26 is a schematic diagram showing a structure in which developing members are provided at both ends of the first embedded bracket and the second embedded bracket in Example 7 of the present invention;

[0042] FIG27 is a schematic diagram of the structure of a transition bracket using a corrugated bracket in Example 7 of the present invention;

[0043] FIG28 is a schematic diagram of a transition bracket using a mesh braided bracket structure in Example 7 of the present invention;

[0044] FIG29 is a schematic diagram of the structure of the special-shaped corrugated ring in the eighth embodiment of the present invention;

[0045] FIG30 is a schematic diagram of a structure of a special-shaped wave coil with high and low waves at the far end in the eighth embodiment of the present invention;

[0046] FIG31 is a schematic diagram of the structure of the hook and the hanging rod in the ninth and tenth embodiments of the present invention;

[0047] FIG32 is a schematic structural diagram of a stent delivery system according to a tenth embodiment of the present invention;

[0048] FIG33 is a schematic structural diagram of the stent graft disposed in the conveyor in the tenth embodiment of the present invention. DETAILED DESCRIPTION

[0049] In order to better understand the concept of the present application, the following detailed description of the implementation methods of the present application is given in conjunction with the accompanying drawings. The following specific embodiments are only some embodiments of the present application and are not limitations of the present application.

[0050] For ease of description, spatially relative terms may be used herein to describe the relationship of one element or feature relative to another element or feature as shown in the figures, such as "inside," "outside," "inside," "outside," "below," "beneath," "above," and the like. Such spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is flipped, an element described as "below" or "below" another element or feature would then be oriented as "above" or "above" another element or feature. Thus, the example term "below" can include both above and below orientations. The device may be otherwise oriented (rotated 90 degrees or in other orientations) and the spatially relative descriptors used herein are interpreted accordingly.

[0051] Although the terms first, second, third, etc. can be used in the text to describe multiple elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms can only be used to distinguish an element, component, region, layer or section from another region, layer or section. Unless the context clearly indicates otherwise, terms such as "first", "second" and other numerical terms do not imply order or sequence when used in the text. Therefore, the first element, component, region, layer or section discussed below can be referred to as the second element, component, region, layer or section without departing from the teaching of the example embodiments.

[0052] To more clearly describe the structure of this application, the terms "proximal" and "distal" are defined here as commonly used in the field of interventional medicine. Specifically, "distal" refers to the end of a blood vessel away from the heart, and "proximal" refers to the end of a blood vessel closer to the heart; "axial" refers to its length, and "radial" refers to the direction perpendicular to the "axial" direction; "upper end" and "lower end" are two ends that are relatively far apart. When one end is defined as the "upper end," the other end that is farther away is the "lower end."

[0053] Example 1:

[0054] Please refer to Figures 1-2. The present invention provides a covered stent 100. The covered stent 100 is generally composed of a metal skeleton and a covering material. The metal skeleton can adopt a Z-shaped wave or woven mesh design. The covering material has a certain blood flow isolation ability and is combined with the metal skeleton through pressurization, heating, suturing, etc. 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 the abdominal aorta stent, and the lumen diameter generally matches the diameter of the common iliac artery.In this embodiment, referring to Figures 1 and 3, the coated stent 100 has a main stent 10 with a tubular body and an embedded stent 20. The main stent 10 is directly placed in the blood vessel and contacts the blood vessel wall. The embedded stent 20 is arranged in the inner cavity of the main stent 10 for blood flow diversion. The surface of the main stent 10 is covered with a first coating 104, and the surface of the embedded stent 20 is covered with a second coating 202; wherein, the main stent 10 includes a proximal segment 101, a tumor cavity segment 102 and a distal segment 103 along the axial direction; the proximal segment 101 is connected to the proximal side of the tumor cavity segment 102, the distal segment 103 is connected to the distal side of the tumor cavity segment 102, and the proximal segment 101 is connected to the distal segment 103 through the tumor cavity segment 102. Communication; When the stent graft 100 is installed in the diseased blood vessel, the tumor cavity segment 102 is generally placed at the tumor cavity position of the blood vessel. The tumor cavity segment 102 is composed of a second channel 1022 and a first channel 1021 arranged along the radial direction. The radial width of the tumor cavity segment 102 is usually set to be larger than the diameter of the distal segment 103 and the diameter of the proximal segment 101, so that the first channel 1021 and the second channel 1022 in the tumor cavity segment 102 have sufficient flow space to avoid being squeezed by the tumor cavity and completely blocked after implantation; the second channel 1022 and the first channel 1021 are isolated to form two relatively independent blood flow channels, namely the external iliac channel and the internal iliac channel. When in use, the first channel 1021 is used to pass the internal iliac stent, and the second channel 1022 is used to connect the extended distal segment 103 to establish circulation with the external iliac artery. In this embodiment, by arranging the embedded stent 20 in the first channel 1021, the first channel 1021 and the second channel 1022 are relatively independent and isolated, and the distal end of the first channel 1021 is provided with an opening 1024 for communicating with the outside world, and the distal end of the embedded stent 20 is communicated with the opening 1024. The arrangement of the embedded stent 20 can make the shape of the formed first channel 1021 compatible with the shape of the internal iliac stent to be implanted, thereby ensuring that the stent has better adaptability both during and after implantation. The embedded stent 20 When arranged in the first channel 1021, at least part of it is connected to the side wall of the first channel 1021 of the tumor cavity segment 102. Preferably, the connection between the embedded bracket 20 and the tumor cavity segment 102 is a surface contact connection by multi-point bonding or suturing. Such an arrangement can ensure that at least the part of the embedded bracket 20 connected to the tumor cavity segment 102 always remains in contact with the tumor cavity segment 102 of the main bracket 10. When the tumor cavity segment 102 is squeezed, the contact part can be deformed at the same time as the deformation of the tumor cavity segment 102, thereby effectively avoiding that when the tumor cavity segment 102 is deformed, the embedded bracket 20 does not deform but only displaces in the inner cavity of the tumor cavity segment 102, affecting the width and passability of the second channel 1022.

[0055] In other embodiments, the covered stent 100 provided in the present application is not only used to reconstruct the common iliac artery, internal iliac artery and external iliac artery, but can also be used to reconstruct the abdominal aorta and the subclavian artery in the aortic arch. When used to reconstruct the abdominal aorta, when the lesion site of vascular diseases such as aneurysm or dissection is located in the abdominal aorta area, the proximal segment 101 of the covered stent 100 can be anchored at the lower edge of the renal artery, and the distal segment 103 is anchored in the common iliac artery. The second channel 1022 connects the abdominal aorta and the common iliac artery, and the first channel 1021 connects the blood flow of the abdominal aorta and the common iliac artery by inserting a stent. When used to reconstruct the right subclavian artery, the lesion site of vascular diseases such as aneurysms or dissections is located in the right subclavian and right common carotid artery regions. The proximal segment 101 of the covered stent 100 can be anchored to the innominate artery, the distal segment 103 is anchored to the right common carotid artery, the second channel 1022 connects the right common carotid artery and the innominate artery, and the first channel 1021 connects the right clavicle artery and the innominate artery by inserting a stent. Alternatively, the proximal segment 101 and the distal segment 103 of the covered stent 100 provided by itself may not be directly anchored on the blood vessel, but may be indirectly fixed by anchoring to other stents. The above is only an example of the more common application positions of the covered stent 100 provided by the present application in the human body, and does not limit the application of the covered stent 100 provided by the present application. When the blood vessel type and the lesion location are appropriate, the covered stent 100 provided by the present application may also be applicable to other bifurcated blood vessel locations in the human body.

[0056] In this embodiment, referring to FIG. 1 and FIG. 2 , in order to ensure that the tumor cavity section 102 of the coated stent 100 obtains a certain degree of support through the embedded stent 20 when the first channel 1021 is squeezed, while ensuring that the second channel 1022 can maintain a good shape to avoid occlusion due to excessive squeezing, the total support strength of the first channel 1021 and the embedded stent 20 of the tumor cavity section 102 of the coated stent 100 of the present application is set to be less than the support strength of the second channel 1022; in this way, the part with small support strength will be deformed first and the deformation amount will be large when it is squeezed, while the part with large support strength will be deformed slowly and the deformation will be large. The amount is limited; thus, the second channel 1022 has a greater supporting strength to ensure that it deforms less when subjected to the same extrusion force as the first channel 1021, thereby maintaining the shape of the second channel 1022. The first channel 1021, due to its smaller supporting strength, deforms first and deforms more, so that the deformation of the tumor cavity segment 102 falls more on the first channel 1021, maintaining the shape of the second channel 1022; and the first channel 1021, due to the provision of the embedded bracket 20, the part of the embedded bracket 20 in the cavity that is not connected to the tumor cavity segment 102 basically does not deform, and can still maintain a good channel shape.

[0057] In this embodiment, please refer to FIG3 , the embedded stent 20 has a mesh body 201 and a second covering 202, wherein the mesh body 201 adopts a mesh-woven stent structure, and the mesh support structure can provide better tension, thereby providing better shape retention, and the mesh body 201 can provide more contact sites when the internal iliac stent is implanted, thereby making the internal iliac stent and the embedded stent 20 have greater friction, which can effectively enhance the adhesion and the anti-slip performance of the stent; please refer to FIG2 , the proximal segment 101 is along the A plurality of proximal support coils 1011 are provided axially, and a plurality of distal support coils 1031 are provided axially at the distal section 103. Both the proximal support coils 1011 and the distal support coils 1031 are Z-shaped annular coils to provide support force. The Z-shaped annular coils can provide support force while leaving a coating gap between the coils, so that the stent can deform at the coating gap position and have good flexibility. The diameter of the proximal support coil 1011 is larger than the diameter of the distal support coil 1031 to adapt to different blood vessel diameters. In other embodiments, the mesh body can also be formed by cutting tubular metal, such as nickel titanium tube, stainless steel tube, etc.

[0058] Among them, the support strength of the first coating 104 is set to be greater than the support strength of the second coating 202. In this embodiment, the first coating 104 adopts PET film and the second coating 202 adopts ePTFE film. The PET film has the characteristics of high tensile strength, while the ePTFE film has weak tensile strength, smooth surface, and is not easy to form blood clots. It has good long-term patency for small-sized blood vessels and small pores. Combining the PET film and the ePTFE film not only ensures the overall strength of the stent coating, but also enables the coated stent 100 to have a better effect of isolating blood flow, ensuring the long-term patency of the branch and good sealing effect. The support strength of the first coating 104 is greater than the support strength of the second coating 202, which can make the support strength of the coating part of the second channel 1022 part greater than the support strength of the embedded stent 20 of the first channel 1021 part, so that the embedded stent 20 is easier to deform than the second channel 1022 part, and thus easily deforms with the deformation of the first channel 1021 part.

[0059] In this embodiment, in order to make the coated stent 100 more easily compressed and have a smaller compressed folding volume when installed on the conveyor, the proximal support wave ring 1011, the distal support wave ring 1031 and the first wave ring 1023 can be sutured to the surface of the first coating by suturing. Specifically, during suturing, at least the wave crests of the proximal support wave ring 1011, the distal support wave ring 1031 and the first wave ring 1023 facing the proximal direction are not sutured with the first coating. In this way, when the coated stent 100 is folded and compressed, since the wave crest position is not constrained by suturing, other suturing points can undergo slight displacement to adapt to the folding of the coating and the deformation of the stent wave ring, so that the coated stent can be better folded; further, the unsutured wave crests can reduce the suturing ratio of the coating, so the coating can have better flexibility to adapt to blood vessels with more complex curvatures.

[0060] In this embodiment, referring to FIG. 2 , the tumor cavity segment 102 includes a plurality of first wave coils 1023 spaced apart in the axial direction. The first wave coils 1023 are also Z-shaped annular wave coils. In order to maintain good flexibility of the tumor cavity segment 102, the plurality of first wave coils 1023 are provided with the same wave number, and the crests and / or troughs of adjacent first wave coils 1023 are provided opposite to each other. Here, the plurality of first wave coils 1023 are provided with the same wave number and the crests and / or troughs are provided opposite to each other, that is, the space between adjacent first wave coils 1023 is approximately 1 / 4 of the width of the first wave coils 1023. The parallel arrangement allows for uniform spacing between adjacent first wave coils 1023, which are connected only by a membrane, resulting in better flexibility, which helps the tumor cavity segment 102 to better conform to the curvature of the blood vessel. Preferably, the wave number of the first wave coil 1023 can be made equal to the wave number of the proximal support wave coil 1011, and the wave crests and / or wave troughs are arranged relative to each other, so that the connection between the tumor cavity segment 102 and the proximal segment 101, as well as the connection between the tumor cavity segment 102 and the proximal segment 101, also maintains good flexibility.

[0061] In this embodiment, referring to Figures 4 and 5, in order to make the total support strength of the first channel 1021 and the embedded stent 20 smaller than the support strength of the second channel 1022, the wave angle of the same first wave coil 1023 of the tumor cavity segment 102 located in the second channel 1022 (angle a in the figure) is greater than the wave angle of the same first wave coil 1023 located in the first channel 1021 (angle b in the figure); this is because the waveform with a larger wave angle requires a greater force to deform when the wave coil is deformed than the waveform with a smaller wave angle, and therefore the support strength is also greater than the waveform with a smaller wave angle; in some embodiments, in order to make the wave angles distinct, adjacent first wave coils 1023 have the same wave number and the crests and / or troughs are arranged relative to each other, so that the wave height of the waveform located in the second channel 1022 is smaller than the wave height of the waveform in the first channel 1021, and the wave angle of the waveform in the second channel 1022 (angle d in the figure) is greater than the wave angle of the waveform in the first channel 1021 (angle c in the figure). In another embodiment, the wave height of all waveforms of the first wave ring 1023 can be gradually increased from the second channel 1022 portion to the first channel 1021 portion, and the wave angle can be gradually reduced to form a structure with gradually decreasing support strength; in this way, the gradual reduction of support strength can avoid the tumor cavity segment 102 from suddenly forming a large support strength difference at the junction of the second channel 1022 portion and the first channel 1021 portion, thereby causing unpredictable and unexpected deformation of the tumor cavity segment 102 at this position.

[0062] In other embodiments, please refer to FIG6 . In order to make the total support strength of the first channel 1021 and the embedded bracket 20 smaller than the support strength of the second channel 1022, the wire diameter R1 of the first wave coil 1023 located in the second channel 1022 can be larger than the wire diameter R2 of the first wave coil 1023 located in the first channel 1021. When the wire diameter is larger, a greater force is required to resist the stiffness of the material itself. Therefore, under the same force, the deformation of the wave coil with a larger wire diameter is less than that of the wave coil with a smaller wire diameter. It has stronger supporting strength; in some embodiments, the braided wire with small wire diameter and the braided wire with large wire diameter can be connected together by means of connectors or fasteners, and after connection, they are placed in the first channel 1021 part and the second channel 1022 part of the tumor cavity segment 102 respectively; the first wave ring 1023 can also be cut and formed as a whole, and its wire diameter can be reduced in the first channel 1021 part by chemical corrosion, physical polishing, etc., or the wire diameter of the first wave ring 1023 can be made to have a tapered structure that gradually decreases from the second channel 1022 part to the first channel 1021 part.

[0063] In order to make the support strength of the embedded stent 20 and the first channel 1021 of the tumor cavity section 102 smaller than that of the second channel 1022, the embedded stent 20 is woven with metal braided wires of smaller wire diameter. In this embodiment, the wire diameter d of the embedded stent 20 is smaller than half of the wire diameter D of the first wave coil 1023 of the second channel 1022, that is, d is smaller than half D, and the wire diameter M of the first wave coil 1023 of the first channel 1021 is also smaller than that of the first wave coil 1023 of the second channel 1022. 23 is half of the wire diameter D, so as to ensure that the sum of the supporting strengths of the embedded bracket 20 and the first channel 1021 part is always smaller than that of the second channel 1022 part; however, the wire diameters of the embedded bracket 20 and the first wave coil 1023 of the first channel 1021 part of the present application are not limited to the above settings. The technicians can adjust the wire diameters of the embedded bracket 20 and the wire diameters of the first wave coil 1023 of the first channel 1021 part according to the actual bracket requirements to ensure that the sum of their supporting strengths is smaller than that of the second channel 1022 part.

[0064] The support strength of the tumor cavity segment 102 at the proximal and / or distal ends may also be greater than the support strength at the middle position. In one embodiment, the support strength of the first wave ring 1023 at the proximal and distal ends of the tumor cavity segment 102 is greater than the support strength of the first wave ring 1023 at the middle position. This setting is because when a blood vessel usually forms a tumor cavity, the intersection of the tumor cavity and the normal blood vessel is usually a location where compression is more severe. The first wave ring 1023 at the proximal and distal ends of the tumor cavity segment 102 is set to have a higher support strength, which can better resist compression from the intersection of the blood vessel and the tumor cavity. Setting the middle position to a lower support strength can make the tumor cavity segment 102 have a certain flexibility and better adapt to the shape of the blood vessel; in other embodiments, only the support strength of the first wave coil 1023 located at the proximal position of the tumor cavity segment 102 can be set to be greater than the support strength of the first wave coil 1023 at the middle position, so as to at least ensure the support strength of the stent at the blood inflow position; in order to achieve the above-mentioned change in support strength, the wire diameter or wave angle of the proximal first wave coil 1023 of the tumor cavity segment 102 can be made greater than the wire diameter or wave angle of the first wave coil 1023 at the middle position.

[0065] In this embodiment, the support strength is specifically manifested as the deformation of the overall tubular inner cavity (the first channel 1021 portion and the second channel 1022 portion) of the coated stent 100 after the tumor cavity segment 102 is compressed, that is, under the same force conditions, the same force (the force needs to make the first channel 1021 portion and the second channel 1022 portion both deform) is used to press the outer walls of the first channel 1021 portion and the second channel 1022 portion, and the radial cross-sectional areas of the first channel 1021 portion and the second channel 1022 portion after pressing are measured and calculated. Here, the bracket with a larger total cross-sectional area measured after compression has a greater support strength, and the bracket with a smaller total cross-sectional area has a smaller support strength; in some embodiments, the first channel 1021 part and the second channel 1022 part that are independently separated can be compressed respectively by a flat-plate dynamometer, and the force required when compressed to the same deformation amount is measured. The larger the measured force, the greater the support strength, and the smaller the measured force, the smaller the support strength. In this embodiment, the force measured in the second channel 1022 part is always greater than the force measured in the first channel 1021 part.

[0066] Example 2:

[0067] In this embodiment, referring to Figures 7 to 9, the structures of the main support 10 and the embedded support 20 are substantially the same as those in the first embodiment, except that the first wave ring 1023 includes a plurality of first wave rods 10232, and the plurality of first wave rods 10232 are connected end to end at an angle to form a Z-shaped or M-shaped annular wave ring, wherein a support member 10233 is provided between adjacent first wave rods 10232, and the support member 10233 is connected to the first covering film 104 between two adjacent first wave rods 10232 by sewing or bonding, and is used for when the two adjacent first wave rods 10232 are deformed by the extrusion force, the two first wave rods 10232 are compressed and moved closer to each other around their wave angle, and when they move to the position of the support member 10233, the support member The two sides of 10233 respectively resist against the two first wave rods 10232 to prevent the two first wave rods 10232 from continuing to move and compress, limit the degree of deformation of the waveform and thus provide support force. In order to make the support strength of the first wave ring 1023 in the second channel 1022 part greater than the support strength in the first channel 1021 part, the multiple support members 10233 are configured to: make the compressible distance between the first wave rods 10232 in the second channel 1022 part smaller than the compressible distance between the first wave rods 10232 in the first channel 1021 part; this is because the compressible distance between the two adjacent first wave rods 10232 is smaller, which reduces the degree of deformation of the waveform, and the first wave ring 1023 has better support performance at this waveform position.

[0068] Please refer to Figures 7 and 8. In one embodiment, in order 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 provide a space for movable deformation between the first wave rod 10232 and the support member 10233. The larger the space, the larger the gap 10234, the greater the degree to which the waveform can be deformed, and the lower the support strength; conversely, the smaller the gap 10234, the smaller the degree to which the waveform can be deformed, and the higher the support strength. Therefore, by setting the gap 10234 between the support member 10233 of the second channel 1022 and the adjacent first wave rod 10232 to be smaller than that of the first channel 10232, the support member 10233 can be provided. The gap 10234 between the support member 10233 and the adjacent first wave rod 10232 in the 21st part can make the support strength obtained by the first wave ring 1023 in the second channel 1022 part greater than the support strength obtained in the first channel 1021 part; with such a configuration, when the first wave ring 1023 is subjected to extrusion pressure, the first wave rods 10232 are deformed relatively close to each other, and when the first wave rod 10232 located in the second channel 1022 part and the support member 10233 resist each other, the first wave rod 10232 located in the first channel 1021 part can still continue to deform, so that the deformation amount of the tumor cavity segment 102 in the first channel 1021 part is greater than the deformation amount in the second channel 1022 part.

[0069] 7 and 8 , the support member 10233 may be a straight-line structure having two end portions. In order to prevent the two end portions of the straight-line structure support member 10233 from piercing the membrane and scratching the blood vessels, the two ends may be bent to form a ring or formed into an anti-damage head end, etc., which is not shown in the figures. It is understandable that the multiple straight-line structure support members 10233 may be support members 10233 with the same length, which are respectively arranged at different axial positions between adjacent first wave bars 10232. For example, in the second channel 1022 portion, the support members 10233 with the same length are arranged near the wave angle position to provide a smaller gap 10234. It is also understandable that the multiple straight-line structure support members 10233 may be support members 10233 with different lengths, which are respectively arranged at the same axial position between adjacent first wave bars 10232. For example, the length of the support member 10233 in the second channel 1022 portion is greater than the length of the support member 10233 in the first channel 1021 portion to provide a smaller gap 10234.

[0070] In another embodiment, please refer to FIG9 , the support member 10233 is an elastic support member 10235, wherein both sides of the elastic support member 10235 are respectively connected to adjacent first wave rods 10232. In this way, the degree of deformation of the two adjacent first wave rods 10232 approaching each other 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, the elastic modulus is small, the deformation degree of the two adjacent first wave rods 10232 approaching each other is large, and the support strength that can be provided is low; and when the elastic support member 10 When the elastic deformation degree of 235 is small, that is, the elastic modulus is large, the deformation degree of the two adjacent first wave rods 10232 that can approach each other is small, and the support strength that can be provided is large; in this way, by setting the elastic modulus of the elastic support member 10235 of the second channel 1022 part to be greater than the elastic modulus of the elastic support member 10235 of the first channel 1021 part; the elastic support member 10235 with a large elastic modulus provides a greater supporting force in the second channel 1022 part, and conversely, the elastic support member 10235 with a small elastic modulus provides a smaller supporting force in the first channel 1021 part.

[0071] In some embodiments, the elastic support member 10235 can be a spring structure, and the two sides of the spring structure are respectively connected to the first wave rods 10232 on both sides, and the elastic modulus of the spring structure of the second channel 1022 part is set to be greater than the elastic modulus of the spring structure of the first channel 1021 part.

[0072] In some other embodiments, please refer to Figure 9, the elastic support member 10235 can be an elastic connecting member with a spring member in the middle and connecting structures on both sides, wherein the deformation distance of the first wave rods 10232 on both sides can be limited by setting the total length of the middle spring member; for example, the length of the spring member of the elastic connecting member of the second channel 1022 is set to be smaller than the length of the spring member of the elastic connecting member of the first channel 1021; the deformation degree that can be provided by the shorter spring member is smaller than the deformation degree that can be provided by the longer spring member, so that under the same force, the shorter spring member reaches the deformation limit first compared to the longer spring member, thereby providing a stable supporting force.

[0073] In other embodiments, referring to FIG. 10 , the axial length of the tumor cavity segment 102 located in the first channel 1021 and the embedded stent 20 can be made shorter than the axial length of the second channel 1022 , thereby reducing the support position when subjected to radial pressure and reducing the area capable of withstanding pressure. In this way, the support strength of the tumor cavity segment 102 located in the first channel 1021 can be made shorter than the support strength of the second channel 1022 .

[0074] In some embodiments, referring to FIG. 10 , the distal port and the opening 1024 of the embedded stent 20 can be set as oblique openings, and the oblique openings are oriented in a direction away from the second channel 1022 ; and the setting of the oblique openings can also make the selection entrance of the internal iliac stent larger when the embedded stent 20 is implanted, thereby reducing the difficulty of selection; the proximal port of the embedded stent 20 is also set as an oblique opening to increase the receiving area for blood flow.

[0075] 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 a marking identification function according to needs, 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.

[0076] Example 3

[0077] In this embodiment, please refer to Figures 11 and 12. The structures of the main support 10 and the embedded support 20 are substantially the same as those in Example 1, except that the first wave ring 1023 is provided with a break 10231 at least in part of the first channel 1021. It can be understood that the first wave ring 1023 is provided with a break 10231 to form a C-shaped wave ring 1026. The first wave ring 1023 does not provide supporting force at the position of the break 10231. The break 10231 is located in the first channel 1021, so that the tumor cavity segment 102 is only covered by the membrane at the position of the first channel 1021, without support from the first wave ring 1023. The supporting force of the first channel 1021 is provided by the embedded support 20, and the supporting strength of the embedded support 20 is lower than the supporting strength of the first wave ring 1023, so that the supporting strength of the tumor cavity segment 102 in the first channel 1021 is less than the supporting strength in the second channel 1022.

[0078] In one embodiment, the fracture 10231 only covers the position where the embedded stent 20 is connected to the membrane of the tumor cavity segment 102, and the broken ends of the C-shaped wave ring 1026 are connected to the two sides of the connection position between the embedded stent 20 and the membrane of the tumor cavity segment 102, that is, the first channel 1021 part of the tumor cavity segment 102 is only connected to the embedded stent 20, and there is no first wave ring 1023 to provide support force. With this arrangement, when the tumor cavity segment 102 is subjected to extrusion pressure, the part of the first channel 1021 connected to the embedded stent 20 is deformed first due to its smaller support strength, thereby effectively avoiding the extrusion from having too much impact on the shape of the second channel 1022.

[0079] Please refer to Figure 20 for further information. The two ends of the C-shaped wave coil 1026 located at the fracture 10231 are wrapped around to form a circular ring structure 10261 or an anti-damage end. The circular ring structure 10261 can store the ends of the metal wires of the braided C-shaped wave coil 1026, thereby preventing the sharp ends from piercing the membrane and scratching the blood vessels.

[0080] Example 4

[0081] In this embodiment, referring to FIG. 13 , the structures of the main stent 10 and the embedded stent 20 are substantially the same as those in the first embodiment, except that the embedded stent 20 in the tumor cavity segment 102 includes a first embedded stent 21 and a second embedded stent 22 arranged radially, wherein the first embedded stent 21 is communicated with the distal segment 103; an opening 1024 is provided at the distal end of the tumor cavity segment 102, and a distal end of the second embedded stent 22 is communicated with the opening 1024; wherein the tumor cavity segment 102 includes a first channel 1021 and a second channel 1022, wherein the second channel 1022 accommodates the first embedded stent 21, and the first channel 1021 accommodates the second embedded stent 22;

[0082] The second channel 1022 and the first channel 1021 are separated by the embedded first embedded bracket 21 and the second embedded bracket 22 to form a blood flow cavity. The first embedded bracket 21 and the second embedded bracket 22 can respectively provide support to maintain the channel shape to avoid occlusion due to pressure; the first embedded bracket 21 is set in the second channel 1022, so that when squeezing occurs, the first embedded bracket 21 of the second channel 1022 has a supporting force that resists the second embedded bracket 22 of the first channel 1021, so that the coated stent 100 of the present application can be implanted in the first iliac stent. While providing a better-shaped passage, the first channel 1021 can also avoid the occlusion of the second channel 1022 caused by excessive squeezing of the second channel 1022 by the first channel 1021, thereby better maintaining the overall shape and smoothness of the dual channels; wherein, the blood inlet of the tumor cavity segment 102 located at the proximal segment 101 and the blood outflow outlet located at the distal end are both occupied by the proximal port and the distal port of the first embedded bracket 21 and the second embedded bracket 22, so that when the blood flows from the proximal segment 101 into the tumor cavity segment 102, it is diverted by the first embedded bracket 21 and the second embedded bracket 22.

[0083] In this embodiment, please refer to Figures 14 to 16. In order to ensure the expanded shape of the second channel 1022 and the patency of its blood flow when the tumor cavity segment 102 is squeezed or the stent is expanded, the present application sets the support strength of the part of the tumor cavity segment 102 of the coated stent 100 that is in the second channel 1022 to be greater than the support strength of the part that is in the first channel 1021; that is, it 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 on the premise that the support strength of the tumor cavity segment 102 is uniform; or on the premise that the support strength of the first embedded stent 21 is equal to the support strength of the second embedded stent 22, the support strength of the second channel 1022 of the tumor cavity segment 102 is greater than the support strength of the first channel 1021; or the support strength of the first embedded stent 21 is set to be greater than the support strength of the second embedded stent 22 and the support strength of the second channel 1022 of the tumor cavity segment 102 is greater than the support strength of the first channel 1021.

[0084] In this embodiment, referring to FIG. 14 and FIG. 15 , the first embedded stent 21 and the second embedded stent 22 both have a mesh body 201 and a second surface coating 202, and the tumor cavity section 102 of the main stent 10 includes a plurality of first wave rings 1023 spaced apart along the axial direction. The mesh body 201 can provide better ductility, and the second surface coating 202 of the first embedded stent 21 and the second embedded stent 22 can be opened more smoothly to prevent local positions from being squeezed and collapsed, and at the same time can provide more support sites to conflict with the iliac internal stent during implantation, thereby increasing friction. By adjusting the first embedded stent 21 and the second internal The wire diameter of the embedded stent 22, as well as the wire diameter of the first wave coil 1023 located in the second channel 1022 and the wire diameter of the first wave coil 1023 located in the first channel 1021, can be adjusted to provide a difference in support strength between the first channel 1021 portion and the second channel 1022 portion of the stent graft 100 located in the aneurysm cavity section 102. 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 making the wire diameter of the first wave coil 1023 located in the second channel 1022 larger than the wire diameter of the first wave coil 1023 located in the first channel 1021;

[0085] Please refer to FIG14 , the wire diameter of the first embedded stent 21 is larger than the wire diameter of the second embedded stent 22, and the wire diameter of the first wave coil 1023 located in the second channel 1022 is larger than the wire diameter of the first wave coil 1023 located in the first channel 1021; the wire diameter of the first wave coil 1023 of the first channel 1021 is small, and when the tumor cavity section 102 is subjected to the squeezing force, the first wave coil 1023 of the first channel 1021 is deformed first before the first wave coil 1023 of the second channel 1022, thereby preferentially affecting the deformation of the second embedded stent 22 located in the first channel 1021, and because the wire diameter of the second embedded stent 22 is It is smaller than the first embedded stent 21, so that the deformation of the second embedded stent 22 is better than that of the first embedded stent 21, and the support strength on the single-layer stent is distributed to the inner and outer two-layer stents for sharing, so that the support strength on a single stent is not too large, and at the same time, the wire diameter of the first wave ring 1023 of the first channel 1021 of the tumor cavity section 102 and the second iliac internal stent are reduced, which can avoid a large difference in wire diameter on a single stent, and the wire diameter of the two stents will not be reduced too thin, thereby avoiding the problem that the stent is difficult to maintain the support effect due to an excessively small wire diameter setting and the flexibility is poor due to a large wire diameter.

[0086] Implementation Five

[0087] In this embodiment, referring to FIG16 , the structures of the main support 10 and the embedded support 20 are substantially the same as those in the first and fourth embodiments, except that, in this embodiment, by making the mesh density of the first embedded support 21 greater than the mesh density of the second embedded support 22, the support strength of the tumor cavity section 102 of the coated support 100 as a whole in the second channel 1022 is set to be greater than the support strength of the part in the first channel 1021. Specifically, the first embedded support 21 and the second embedded support 22 include a mesh body 201, and the mesh body 201 has multiple mesh structures. A higher mesh density means an increase in the number of braided wires required, and a smaller area of ​​a single mesh means a greater pressure that can be withstood, and a larger mesh density can provide a greater support strength.

[0088] In this embodiment, referring to FIG. 16 , the first embedded stent 21 and the second embedded stent 22 have a woven diamond grid structure. The first embedded stent 21 has a first diamond grid, and the second embedded stent 22 has a second diamond grid. The first diamond grid and the second diamond grid each have an upper vertex and a lower vertex in the axial direction and a left vertex and a right vertex in the radial direction. The spacing between the upper and lower vertices of the first diamond grid is D1, and the spacing between the left and right vertices is L1. The spacing between the upper and lower vertices of the second diamond grid is D2, and the spacing between the left and right vertices is L2. Preferably, D1 and L1 can be made smaller than D2 and L2, so that the area occupied by a single first diamond grid is smaller than the area occupied by a single second diamond grid. Thus, under the same stent deployment area, the first embedded stent 21 has a higher grid density, providing stronger support strength than the second embedded stent 22.

[0089] In another embodiment, please continue to refer to Figure 16, the L1 of the first diamond grid can be at least made smaller than the L2 of the second diamond grid, so that the density of the first diamond grid is changed only in the circumferential direction of the first embedded bracket 21. In this way, the density of the first diamond grid can be increased at least in the radial direction, thereby achieving the effect of enhancing the support strength in the radial direction.

[0090] In one embodiment, the wave angle of the first wave loop 1023 of the tumor cavity segment 102 located in the second channel 1022 is greater than the wave angle of the first wave loop 1023 located in the first channel 1021; in another embodiment, the wave height of all waveforms of the first wave loop 1023 can be gradually increased from the second channel 1022 portion to the first channel 1021 portion, and the wave angle can be gradually reduced to form a structure with gradually decreasing support strength; in this way, the gradual reduction of support strength can avoid the tumor cavity segment 102 suddenly forming a large support strength difference at the junction of the second channel 1022 portion and the first channel 1021 portion, thereby causing unpredictable and unexpected deformation of the tumor cavity segment 102 at this position. By simultaneously making the grid density of the first embedded bracket 21 greater than the grid density of the second embedded bracket 22 and the wave angle of the first wave coil 1023 in the second channel 1022 greater than the wave angle of the first wave coil 1023 in the first channel 1021, and at the same time setting changes in support strength on the first wave coil 1023 of the tumor cavity segment 102 and the first embedded bracket 21 and the second embedded bracket 22, the problem of poor flexibility of the bracket in some positions that may be caused by setting changes in support strength only on the first embedded bracket 21 and the second embedded bracket 22 or setting strength changes on the first wave coil 1023 of the tumor cavity segment 102 can be avoided.

[0091] It can be understood that by making the grid density of the first embedded bracket 21 greater than the grid density of the second embedded bracket 22, and / or the wave angle of the first wave ring 1023 located in the second channel 1022 greater than the wave angle of the first wave ring 1023 located in the first channel 1021, the support strength of the tumor cavity section 102 of the coated bracket 100 as a whole in the second channel 1022 can be set to be greater than the support strength of the part located in the first channel 1021.

[0092] Example 6

[0093] In this embodiment, referring to Figures 17 to 19, the structures of the main support 10 and the embedded support 20 are substantially the same as those in the first embodiment and the fourth to fifth embodiments, except that the support strength of the tumor cavity segment 102 in the first channel 1021 and the second channel 1022 is changed by providing different axial lengths (H1 and H2 in Figure 17) of the first channel 1021 and the second channel 1022; specifically, the axial length H2 of the second channel 1022 is greater than the axial length H1 of the first channel 1021, and the tumor cavity segment 102 has an axial length H2 in the second channel 1022. A channel 1021 has an axial length H1, and the length of H2 is greater than the length of H1, so that when the second channel 1022 of the tumor cavity section 102 is under pressure, the length and contact area that can withstand pressure are greater than the compressed length and contact area of ​​the first channel 1021, thereby better dissipating the pressure, providing better support performance, and improving support strength; please refer to Figures 18 and 19, wherein the distal end of the second embedded stent 22 includes an exposed section 221, which passes through the opening 1024 and passes through the first channel 1021, so that the first channel 1021 of the coated stent 100 also has There is a distribution of different support strengths. At the intervention end of the internal iliac stent, only the second embedded stent 22 single-layer stent serves as support, so that it has better flexibility at this position, thereby facilitating the selection of the internal iliac stent; further, the distal end of the exposed section 221 is flat or oblique; when set to a flat end, the exposed section 221 can have more attachment support positions with the intervened internal iliac stent, thereby effectively improving the long-term stability of the internal iliac stent after intervention; and when set to an oblique end, the opening direction of the oblique end is in the direction away from the second channel 1022, so that the internal iliac stent can be expanded without expanding the diameter of the second embedded stent 22. The selection entrance of the stent makes the selection of the internal iliac stent faster and more convenient; and the enlarged selection entrance can also improve the accuracy of the selection of the internal iliac stent; in some embodiments, the exposed section 221 is fitted with the adjacent second channel 1022, and the exposed section 221 can be a free end and can be separated from the second channel 1022. Such a setting can ensure that after the internal iliac stent is implanted, it will not be subjected to excessive pressure at this position when extending to the internal iliac blood vessel, thereby causing problems such as compression and occlusion; the exposed section 221 can also be fixedly connected to the side wall of the second channel 1022 by suturing or bonding to avoid swinging, so that the internal iliac stent can be better selected.

[0094] 18-19, since the second embedded stent 22 passes through the opening 1024 of the tumor cavity segment 102, there is only a single-layer stent at the opening 1024, and the support is greatly weakened compared with other positions. In order to ensure that the tumor cavity segment 102 of the coated stent 100 of the present application is more easily deformed at the first channel 1021 position than at the second channel 1022 position when squeezed, while avoiding the compression and occlusion of the selected entrance of the exposed segment 221, the support of the stent of the second channel 1022 close to the exposed segment 221 is weakened, and the second channel 1022 can be At least the first wave ring 1023 of the channel 1022, which is located at the same axial position as the exposed section 221, is provided with a fracture 10231 to form a C-shaped wave ring 1026, and the fracture 10231 is facing the exposed section 221. With this arrangement, the support of the position where the second channel 1022 contacts the exposed section 221 is effectively weakened, so that when the iliac stent selection port of the exposed section 221 is compressed and the position where the second channel 1022 abuts against it can undergo a certain amount of deformation, thereby buffering the extrusion force and preventing the selection port from being further squeezed.

[0095] Similar to the third embodiment, the two ends of the C-shaped wave coil 1026 at the fracture 10231 are wrapped around to form a circular ring structure, which can store the ends of the metal wires braided with the C-shaped wave coil 1026, thereby preventing the sharp ends from piercing the membrane and scratching the blood vessels.

[0096] In this embodiment, please refer to FIG20 . In order for the coated stent 100 to better adapt to the morphology of the diseased blood vessel, a proximal wave ring 1025 is provided at the proximal position of the tumor cavity segment 102. The proximal wave ring 1025 at the proximal end of the tumor cavity segment 102 is set to have a diameter at the proximal end that is smaller than the diameter at the distal end, so that the proximal wave ring 1025 has an inclined angle, forming a stent structure that is narrow near and wide far away. In this way, the tumor cavity segment 102 of the coated stent 100 forms a gradual transition structure from wide to narrow at the position where it connects with the proximal segment 101, so as to adapt to the change in diameter from normal blood vessels to diseased blood vessels, enhance the anchoring of the proximal segment 101 to the blood vessel, and improve the stability of the coated stent 100 after implantation. In this embodiment, in order to ensure that the first channel 1021 and the second channel 1022 of the tumor cavity segment 102 have better permeability, the radial dimension of the tumor cavity segment 102 is made larger than that of the proximal segment 101 and the distal segment 103, and the setting of the first embedded stent 21 and the second embedded stent 22 can ensure the blood permeability of the first channel 1021 and the external iliac access, wherein the tumor cavity blood vessels also have a size change from large to small compared with the proximal blood vessels, so that the setting of the proximal wave ring can conform to this structure while enhancing the surface adhesion of the coated stent 100 of the present application, avoiding the swing of the stent in the blood vessel, and avoiding the stent slipping and displacement in the blood vessel.

[0097] In other embodiments, please refer to Figure 21, the proximal port and distal port of the first embedded stent 21 and the second embedded stent 22 can be set as flat ports or oblique ports, respectively. For example, the proximal port and distal port of the second embedded stent 22 are both set as parallel oblique ports, and the proximal port of the first embedded stent 21 is set as an oblique port. In this way, the second embedded stent 22 can be further formed into an unstable parallelogram structure so that it has staggered support points in the radial direction, which is easy to deform when under pressure to reduce the support strength. The oblique port setting 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.

[0098] In this embodiment, the surface of the main support 10 is covered with a first coating 104, and the surfaces of the first embedded support 21 and the second embedded support 22 are covered with a second coating 202. The supporting strength of the first coating 104 is greater than the supporting strength of the second coating 202. The first coating 104 is made of PET film and the second coating 202 is made of ePTFE film. Here, the change in the supporting strength of the first coating 104 and the second coating 202 is mainly reflected in the characteristics of the material itself. The tensile strength of the PET film used in the first coating 104 is generally between 50-200 MPa, and it has good impact resistance. performance, while the tensile strength of the ePTFE membrane used in the second coating 202 is usually between 23-30MPa, and the impact resistance is poor; therefore, the use of the first coating 104 and the second coating 202 with different tensile strengths can make the main support 10 and the first embedded support 21 and the second embedded support 22 have different support strengths at the coating level, so as to better cooperate with the support itself to set different support strengths; the purpose of using ePTFE membrane for the first embedded support 21 and the second embedded support 22 is to improve blood permeability while minimizing the influence of the coating on the support strength.

[0099] In another embodiment, in order to make the coated stent 100 provided by the present application better adapt to the diseased iliac artery, the support strength of the distal segment 103 and the proximal segment 101 of the coated stent 100 is set to be greater than the total support strength of the tumor cavity segment 102, the first embedded stent 21 and the second embedded stent 22. This is set because the tumor cavity segment 102 itself has support strength, and if the first embedded stent 21 and the second embedded stent 22 are set, the support strength at this position of the coated stent 100 is measured by the total support strength of the tumor cavity segment 102, the first embedded stent 21 and the second embedded stent 22. The support strength of the distal segment 103 and the proximal segment 101 of the coated stent 100 is set to be greater than the total support strength of the tumor cavity segment 102, the first embedded stent 21 and the second embedded stent 22, so that the coated stent 100 has better support in both the proximal and distal blood vessels close to the iliac artery lesion position, thereby improving the anchoring force between the stent and the blood vessels, and firmly anchoring the coated stent 100 of the present application in the release position; and the purpose of weakening the support strength at the tumor cavity segment 102 position is to make it have better flexibility and thus improve compliance, and better fit the shape of the blood vessel in the tumor cavity segment 102 to avoid poor adhesion. In some other embodiments, the support strength of the distal segment 103 or the proximal segment 101 of the coated stent 100 is set to be greater than the total support strength of the tumor cavity segment 102, the first embedded stent 21, and the second embedded stent 22; a larger support strength is set at either the proximal segment 101 or the distal segment 103 to ensure that the tumor cavity segment 102 has good flexibility, while at least one end has good support anchoring performance to ensure the stability of the coated stent 100 when anchored in the blood vessels in the body.

[0100] In some embodiments, this can be achieved by simultaneously reducing the support strength of the first embedded stent 21 and the second embedded stent 22 and the tumor cavity segment 102, for example, the overall support strength of the first embedded stent 21 and the second embedded stent 22 is less than half of the support strength of the proximal segment 101 or the distal segment 103, and the support strength of the tumor cavity segment 102 is less than half of the support strength of the distal segment 103.

[0101] Example 7

[0102] In this embodiment, please refer to Figures 22 and 23. The structures of the main stent 10 and the embedded stent are substantially the same as those in Example 1 and Example 4 to Example 6. The difference is that the main stent 10 is provided with support wave rings at the proximal section 101 and the distal section 103, while the tumor cavity coating section 102 is not provided with the first wave ring 1023 and is only covered with a coating. The inner cavity of the tumor cavity coating section 102 is provided with a first embedded stent 21 and a second embedded stent 22, and support performance is provided by the first embedded stent 21 and the second embedded stent 22; wherein, the proximal section 101, the tumor cavity coating section 102 and the distal section 103 of the main stent 10 can be connected by the first coating 104, the surfaces of the proximal section 101 and the distal section 103 are provided with support wave rings, and the tumor cavity coating section 102 is only provided with a coating; the proximal section 101 and the tumor cavity coating section 102 can also be connected by a single piece of coating, and the distal section 103 is connected by bonding or suturing. 24 , the first embedded stent 21 and the second embedded stent 22 include a mesh body 201, and the purpose of setting the mesh body 201 is to emphasize better morphological support; compared with the supporting wave ring, the mesh body 201 can have better coating tension, so that even when a smaller braided wire diameter is provided, it can still provide better coating tension to maintain the shape of the blood pathway; the tumor cavity coating segment 102 only covers the coating, and when a smaller wire diameter is set for the first embedded stent 21 and the second embedded stent 22, the overall support strength of the coated stent 100 in the tumor cavity coating segment 102 is smaller than that of the proximal segment 101 and the distal segment 103, so that the tumor cavity coating segment 102 as a whole can maintain the shape and passability of the first channel 1021 and the second channel 1022 while having better flexibility.

[0103] In this embodiment, referring to Figures 23 to 26, the first embedded stent 21 and the second embedded stent 22 are connected to the first covering 104 of the tumor cavity covering segment 102 at least at the distal end position of the distal end and the proximal end position of the proximal end thereof by bonding or suturing, wherein the blood inlet at the proximal end and the blood outlet at the distal end of the tumor cavity covering segment 102 are both occupied by the proximal end and the distal end of the first embedded stent 21 and the second embedded stent 22, so that when the blood flows from the proximal segment 101 into the tumor cavity covering segment 102, it is diverted by the first embedded stent 21 and the second embedded stent 22, thereby avoiding internal leakage in the tumor cavity covering segment 102; the proximal end and the distal end of the first embedded stent 21 and the second embedded stent 22 can be set as flat ends or oblique ends;

[0104] Please refer to Figure 24. In order to improve the permeability of blood flow and make the tumor cavity coating section 102 have better flexibility, the proximal ports of the first embedded stent 21 and the second embedded stent 22 are set to be bevels, wherein a first proximal bevel 211 is provided at the proximal end of the first embedded stent 21, and a second proximal bevel 222 is provided at the proximal end of the second embedded stent 22. The first proximal bevel 211 and the second proximal bevel 222 are arranged opposite to each other, and the two bevels form a V-shaped cross-section on the axial section; in this way, the double bevel setting of the first embedded stent 21 and the second embedded stent 22 can increase the receiving area of ​​the blood inlet at the blood inlet position of the tumor cavity coating section 102, so that the blood flow is smoother; and the bevel setting reduces the support points of the first embedded stent 21 and the second embedded stent 22 on both sides of the radial direction, thereby reducing the support strength in the radial direction to a certain extent, so that the coated stent 100 is located at the tumor cavity coating. The supporting strength of the membrane segment 102 is less than that of the proximal segment 101 and the distal segment 103; and, usually, when the stent is bent, the larger curved side is the extended part, and the smaller curved side is the compressed part. The first proximal bevel 211 and the second proximal bevel 222 are set to a double-bevel design set opposite to each other, so that when the coated stent 100 is bent, the larger curved side is on the side of the first proximal bevel 211 or the second proximal bevel 222 with a longer bevel extension length, and the smaller curved side is on the side with a shorter bevel extension length. Therefore, when bending, the bevel structure of the first proximal bevel 211 and the second proximal bevel 222 just conforms to the bending structure of the stent, the side with a longer bevel extension length is on the larger curved side, and the side with a shorter bevel extension length is on the smaller curved side, so that the coated stent 100 has better flexibility at least in the part of the tumor cavity coated segment, and when the coated stent 100 is bent, it can effectively prevent the embedded stent from bending in the tumor cavity coated segment 102.

[0105] In other embodiments, the setting of the first proximal bevel 211 and the second proximal bevel 222 can cause the long axis side walls and short axis side walls of the first embedded stent 21 and the second embedded stent 22 to be offset, so that when the coated stent 100 of the present application is compressed and placed into the delivery sheath, the long axis side walls and short axis side walls of the offset structure can make the first embedded stent 21 and the second embedded stent 21 smaller in size after folding, and easier to deliver into the delivery sheath.

[0106] In this embodiment, please refer to Figures 24 and 26. The distal end of the first embedded stent 21 is an oblique or flat end, and the distal end of the second embedded stent 22 is also an oblique or flat end, and the distal blood outflow outlet of the tumor cavity covering segment 102 is flush with the distal ends of the first embedded stent 21 and the second embedded stent 22, and is fixed by bonding or suturing; wherein, the distal end of the second embedded stent 22 is provided with a second distal oblique opening 223, and the distal end of the first embedded stent 21 is provided with a first distal oblique opening 213 or a flat end; please refer to Figure 26, when the distal ends of the first embedded stent 21 and the second embedded stent 22 are set as oblique openings, the first distal oblique opening 213 and the second distal oblique opening 223 are respectively aligned with the first proximal oblique opening 211 And it is parallel to the second proximal bevel 222; compared with the rectangle, the supporting force of the opposite sides of the non-rectangular parallelogram is smaller than the supporting force of the opposite two sides of the rectangle; in this way, the parallel bevels can make the supporting positions on the radial sides of the first embedded bracket 21 and the second embedded bracket 22 form a staggered structure, so that 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 to achieve the effect of reducing the radial supporting force, so that the first embedded bracket 21 and the second embedded bracket 22 have better flexibility while providing pipeline shape retention force, so that the tumor cavity coating section 102 of the coated bracket 100 has better flexibility.

[0107] In another embodiment, referring to FIG. 24 , the distal end of the second embedded stent 22 is a second distal oblique end 223 , and the distal end of the first embedded stent 21 is a first distal flat end 212 . This configuration allows the axial length H3 of the first embedded stent 21 away from the second embedded stent 22 to be greater than the axial length H4 of the second embedded stent 22 away from the first embedded stent 21 . This allows the first embedded stent 21 to have more stent support positions to disperse the squeezing force from the blood vessel, thereby having better support strength than the second embedded stent 22 .

[0108] Please refer to Figure 25. When the distal end of the first embedded stent 21 is set as an oblique end, the supporting wave ring at the connection position between the distal segment 103 and the tumor cavity is an inclined structure adapted to the first distal oblique end 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 is in a gradually lowering structure, or a break is formed on the side with low wave height.

[0109] In this embodiment, please refer to Figure 25, in which the coated stent 100 also includes a transition section 1027 connected between the proximal section and the tumor cavity coated section 102. When the proximal ends of the first embedded stent 21 and the second embedded stent 22 are set as double bevels, the transition section 1027 is located between the proximal end of the tumor cavity coated section 102 and the first proximal bevel 211 and the second proximal bevel 222, wherein the transition section 1027 is provided with a transition bracket 10271, and the transition bracket 10271 can support the coating of the transition section 1027 formed between the double bevels, thereby avoiding collapse or poor release due to lack of support structure at this position of the tumor cavity coated section 102.

[0110] In this embodiment, please refer to Figures 27-28. The transition bracket 10271 is separately arranged on the transition section 1027, and the shape of the transition bracket 10271 is adapted to the shape of the transition section 1027. Here, since the distal end of the supporting wave ring of the proximal section 101 close to the tumor cavity covering section 102 is a flat mouth with uniform wave height, and a V-shaped mouth is formed between the first proximal oblique mouth 211 and the second proximal oblique mouth 222, in order to make the transition bracket 10271 flush with the proximal end of the tumor cavity covering section 102 and the first proximal oblique mouth 211 and the second proximal oblique mouth 222 at the proximal and distal ends respectively, the proximal end of the transition bracket 10271 includes a flat mouth, and the distal end includes a protruding V-shaped protrusion.

[0111] In some embodiments, the transition bracket 10271 can be an annular bracket or a separate sheet bracket; when the transition bracket 10271 is set as an annular bracket, at least two V-shaped protrusions are set and symmetrically arranged on both sides of the annular bracket, which are used to adapt to the V-shaped openings formed by the first proximal oblique opening 211 and the second proximal oblique opening 222. The annular bracket can provide better overall support performance, not only providing support in the transition section 1027 area, but also providing support at the intersection of the proximal section 101 and the tumor cavity coating section 102, so that the coating bracket 100 can be more stable at the intersection of the proximal section 101 and the tumor cavity coating section 102. The transition position connection of the cavity covering section 102 is more stable; when the transition bracket 10271 is set as a separate sheet bracket, the sheet bracket is provided with at least two pieces, which are symmetrically arranged on both sides of the V-shaped opening formed by the first proximal bevel 211 and the second proximal bevel 222, and the proximal side of the single-piece sheet bracket is a flat edge, and the distal side is a V-shaped edge with a middle bulge and gradually lowered on both sides; the single-piece sheet bracket directly provides support force on the transition sections 1027 on both sides, which can ensure that the transition section 1027 is supported while making the proximal section 101 and the tumor cavity covering section 102 have better flexibility.

[0112] Among them, in one embodiment, please refer to Figures 27 and 28, the transition stent 10271 is a wave coil stent with a Z-shaped or W-shaped weaving structure, and the form of the wave coil stent is similar to the structure of the proximal support wave coil 1011 of the proximal segment 101, so that it has a better connection with the proximal segment 101 at this position, thereby improving the overall flexibility of the coated stent 100; in another embodiment, the transition stent 10271 is a mesh woven stent with a mesh woven structure, and the structure of the mesh woven stent is similar to the structure of the first embedded stent 21 and the second embedded stent 22, so that the integrity of the tumor cavity coated segment 102 is higher, and the supporting tension of the mesh woven stent is stronger, making the inner wall smoother, which can further ensure the patency of blood flow at this position.

[0113] Example 8

[0114] In this embodiment, please refer to Figures 29 and 30. The structures of the main support 10 and the embedded support 20 are substantially the same as those in Example 7. The difference is that the transition support 10271 is not provided separately. A special-shaped wave ring 1012 is provided at the distal end of the proximal section 101. The special-shaped wave ring 1012 extends to the transition section 1027 within the tumor cavity covering section 102 to form a support structure to form the transition support 10271. The proximal end has a uniform proximal wave 102711 of equal height, and the distal end includes a plurality of distal high waves 102712 with unequal heights. The distal high waves 102712 bulge toward the distal end, and the apex is flush with the first proximal oblique opening 211 and the second proximal oblique opening 222 of the first embedded bracket 21 and the second embedded bracket 22 to support the transition section 1027; the distal high waves 102712 of the special-shaped wave ring 1012 are provided with at least two, and the two distal high waves 102712 are along the special-shaped wave ring. The diameter of the circle 1012 is symmetrically arranged on both sides of the distal end, and the apex of the two distal high waves 102712 is close to the bottom of the V-shaped opening; please refer to Figure 29 for further information. The distal high waves 102712 of the special-shaped wave circle 1012 can also be provided with multiple, and a peak-like structure with the highest wave height in the middle and gradually decreasing wave height towards both sides is formed on the opposite sides of the distal end of the special-shaped wave circle 1012 to adapt to the shape of the transition section 1027; the supporting wave circle at the distal end of the proximal section 101 is set as a special-shaped wave. The ring 1012 can prevent the transition section 1027 from lacking a supporting structure, causing local collapse or poor release that affects blood circulation. At the same time, the structure of the special-shaped wave ring 1012 extending between the proximal section 101 and the tumor cavity coating section 102 can make the connection force of the coated stent 100 between the proximal section 101 and the tumor cavity coating section 102 stronger, and the integrity of the stent is higher, thereby avoiding bending at the transition position between the tumor cavity coating section 102 and the proximal section 101.

[0115] Embodiment 9

[0116] In this embodiment, the structures of the main stent 10 and the embedded stent 20 are substantially the same as those in Examples 7 to 8, except that the distal segment 103 of the main stent 10 and the tumor cavity covering segment 102 are spliced ​​and fixed by bonding 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, and the first covering 104 is a PET film, and the second covering 202 is an ePTFE film. The distal segment 103 and the tumor cavity covering segment 102 are spliced, so that the surface covering of the distal segment 103 can also adopt an ePTFE film to further ensure the patency of blood flow in the external iliac vessels.

[0117] In one embodiment, the first embedded stent 21 and the distal segment 103 are integrally formed, and the distal segment 103 directly extends into the tumor cavity covering segment 102 and is sutured with the tumor cavity covering segment 102. The second channel 1022 portion located in 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. In this way, the stent body formed integrally with the first embedded stent 21 and the distal segment 103 can adopt a wave stent or a mesh braided stent, and the surface covering The membrane is made of ePTFE membrane. Here, one-piece molding means that the first embedded stent 21 and the distal segment 103 are molded on the same ePTFE covering membrane, and the formed integral stent does not have an adhesive structure or a suture structure; molding the first embedded stent 21 and the distal segment 103 as one piece can make it possible for the blood flow to enter the second channel 1022 and flow toward the external iliac blood vessels without obstructions or protrusions caused by the splicing structure in the channel that affect the smoothness of its inner wall, which can effectively further improve the patency of the blood flow.

[0118] In this embodiment, please refer to Figure 26, the proximal port and / or distal port of the first embedded bracket 21 and the second embedded bracket 22 are provided with a developing component 203; the proximal port and distal port of the first embedded bracket 21 and the second embedded bracket 22 are both provided with a developing component 203. The setting of the developing component 203 can help the operator quickly locate the position of the tumor cavity covering segment 102 and the relative position of the first channel 1021 and the second channel 1022 as well as the morphological changes after compression through the developing equipment, and can also help the operator quickly locate the selected entrance position of the internal iliac bracket to achieve rapid and accurate implantation of the internal iliac bracket.

[0119] In this embodiment, please refer to FIG31 , in order to achieve that the provided covered stent 100 can complete the initial release in the blood vessel and still be able to fine-tune the release position when the position is inaccurate, a plurality of hooks 1013 are provided on the proximal section 101 of the main stent 10, and the hooks 1013 are provided in plurality and arranged along the axial direction of the proximal section 101, and at least two hooks 1013 are provided at the same axial position, so that the two hooks 1013 at the same axial position can be pulled to the same position and then hooked on the hanging rod 30, and the hooks 1013 at different axial positions can be pulled to the same position and then hooked on the hanging rod 30. After 013 are hooked on the hanging rod 30, at least the proximal section 101 of the coated stent 100 can be at least partially diametrically contracted, so that the stent is in a semi-constrained state after being first released from the catheter of the conveyor and is not fully released. At this time, if the release position is inaccurate, the release position can be fine-tuned and then the hanging rod 30 can be pulled out to fully release the stent; wherein, the hook 1013 can be an annular hook made of a polymer material, such as an annular wire made of PET material; it can be fixed to the proximal support wave ring 1011 of the proximal section 101 or the coating by suturing or bonding.

[0120] Example 10

[0121] In this embodiment, please refer to Figures 32-33, a stent delivery system 1000 is provided, which includes the coated stent 100 provided in Examples 1 to 9, and also includes a conveyor 200, which is used to deliver the coated stent 100 of the present application to a designated blood vessel position and release it, wherein the conveyor 200 generally includes a delivery sheath 2001 and a delivery handle 2002, and the delivery handle 2002 is used to control the advance and retreat of the delivery sheath 2001 to release the stent from the delivery sheath 2001, please refer to Figure 31, wherein the delivery sheath 2001 includes a hanging rod 30, and the hanging rod 30 is used to hook the hook 1013 on the proximal section 101 of the coated stent 100, so that after hooking, at least the proximal section 101 of the coated stent 100 is in a semi-constrained state.

[0122] In this embodiment, a pre-installed guide wire 40 is provided in at least the first channel 1021 of the tumor cavity coated section 102 of the coated stent 100. The prefabricated guide wire is pre-placed in the coated stent 100 of this application after the production is completed. In this way, when the stent is released, there is no need to re-introduce the guide wire. By providing a pre-installed guide wire 40 in the first channel 1021 of the tumor cavity coated section 102, the operation of introducing and selecting the guide wire can be reduced. The internal iliac stent can be quickly guided to the first embedded stent 21 of the first channel 1021 for release directly through the guidance of the pre-installed guide wire 40, thereby improving the accuracy of the release and reducing the operation time.

[0123] The above specific embodiments are only some embodiments of the present invention and are not limitations of the present invention. This specification cannot be an exhaustive list of all embodiments of the present invention. Some features of the above different embodiments can be replaced or combined with each other. Those skilled in the art can also make simple replacements according to actual needs. The concept of the present invention shall be subject to the required scope of protection.

Claims

1. A covered stent, characterized in that, It includes a main body stent with a tubular main body and an embedded stent. The main body stent axially includes a proximal segment, a aneurysmal cavity segment, and a distal segment; the proximal segment is communicated with the distal segment through the aneurysmal cavity segment; the aneurysmal cavity segment includes a first channel and a second channel arranged radially, the second channel is communicated with the distal segment, and an opening communicating with the outside is provided at the distal end of the first channel; the embedded stent is arranged in the first channel, at least part of the embedded stent is connected to the side wall of the first channel, and the distal end of the embedded stent is communicated with the opening; the total support strength of the first channel and the embedded stent is less than the support strength of the second channel.

2. The covered stent according to claim 1, characterized in that, The aneurysmal cavity segment includes a plurality of first corrugated rings arranged axially at intervals, the number of waves of the plurality of first corrugated rings is the same, and the wave peaks and / or wave valleys of adjacent first corrugated rings are arranged oppositely.

3. The covered stent according to claim 2, wherein, At least part of the first corrugated ring located in the first channel is provided with a break.

4. The covered stent according to claim 2, wherein The wave angle of the first corrugated ring located in the second channel part is greater than the wave angle of the same first corrugated ring located in the first channel part, or the wire diameter of the first corrugated ring located in the second channel part is greater than the wire diameter of the same first corrugated ring located in the first channel part.

5. The covered stent according to claim 2, characterized in that, The first corrugated ring includes a plurality of first corrugated rods, and support members are arranged between adjacent first corrugated rods. The plurality of support members are configured such that the compressible distance between the first corrugated rods at the second channel part is less than the compressible distance between the first corrugated rods at the first channel part.

6. The covered stent according to claim 5, characterized in that, There is a gap between the support member and the adjacent first corrugated rod, and the gap at the second channel part is less than the gap at the first channel part.

7. The covered stent according to claim 5, wherein The support member is an elastic support member, both sides of the elastic support member are respectively connected to two adjacent first corrugated rods, and the elastic modulus of the elastic support member at the second channel part is greater than the elastic modulus of the elastic support member at the first channel part.

8. The covered stent according to claim 1, characterized in that, The proximal segment includes a plurality of proximal support corrugated rings arranged axially at intervals, the distal segment includes a plurality of distal support corrugated rings arranged axially at intervals, and the embedded stent includes a reticular main body.

9. The covered stent according to claim 1, characterized in that, The surface of the main body stent is covered with a first film, the surface of the embedded stent is covered with a second film, and the support strength of the first film is greater than the support strength of the second film.

10. The covered stent according to any one of claims 1-9, characterized in that, The support strength of the aneurysmal cavity segment at the proximal and distal ends is greater than that at the middle position.

11. The covered stent according to any one of claims 1-9, characterized in that, The support strength of the aneurysmal cavity segment at the proximal or distal end is greater than that at the middle position.

12. The covered stent according to claim 1, wherein, The embedded stent includes a first embedded stent and a second embedded stent. The first embedded stent is arranged in the second channel, the second embedded stent is arranged in the first channel, and the first embedded stent is communicated with the distal segment; an opening communicating with the outside is provided at the distal end of the aneurysmal cavity segment, and the distal port of the second embedded stent is communicated with the opening; the support strength of the first embedded stent and the second channel is greater than the support strength of the second embedded stent and the first channel.

13. The covered stent according to claim 12, characterized in that, The second channel houses the first inner stent, the first channel houses the second inner stent, the support strength of the first inner stent is greater than that of the second inner stent and / or the support strength of the second channel is greater than that of the first channel.

14. The covered stent according to claim 13, wherein, The first inner stent and the second inner stent include a mesh body, and the aneurysm cavity segment includes a plurality of first corrugated rings arranged at intervals along the axial direction.

15. The covered stent according to claim 14, characterized in that, The wire diameter of the first inner stent is greater than that of the second inner stent, and / or the wire diameter of the first corrugated ring at the second channel is greater than that of the first corrugated ring at the first channel.

16. The covered stent according to claim 14, wherein The mesh density of the first inner stent is greater than that of the second inner stent, and / or the wave angle of the first corrugated ring at the second channel is greater than that of the first corrugated ring at the first channel.

17. The covered stent according to claim 14, characterized in that, The axial length of the second channel is greater than that of the first channel, and the distal end of the second inner stent includes an exposed section that penetrates out of the opening.

18. The covered stent according to claim 17, characterized in that, The second channel is provided with a break at least at the first corrugated ring located at the same axial position as the exposed section, and the break faces the exposed section.

19. The covered stent according to claim 12, wherein The proximal end of the aneurysm cavity segment is provided with a transition corrugated ring, and the proximal diameter of the transition corrugated ring is smaller than its distal diameter.

20. The covered stent according to claim 12, wherein, The surface of the main stent is covered with a first film, the surfaces of the first inner stent and the second inner stent are covered with a second film, and the support strength of the first film is greater than that of the second film.

21. The covered stent according to any one of claims 12-20, characterized in that, The support strength of the distal segment and the proximal segment is greater than the total support strength of the aneurysm cavity segment, the first inner stent, and the second inner stent.

22. The covered stent according to any one of claims 12-20, characterized in that, The support strength of the distal segment or the proximal segment is greater than the total support strength of the aneurysm cavity segment, the first inner stent, and the second inner stent.

23. The covered stent according to claim 1, wherein The aneurysm cavity segment includes an aneurysm cavity film segment, the proximal segment is connected to the distal segment through the aneurysm cavity film segment; the proximal segment and the distal segment are provided with support corrugated rings; the inner stent is provided with a first inner stent and a second inner stent arranged radially in the aneurysm cavity film segment, and the first inner stent connects the proximal segment and the distal segment; the distal end of the aneurysm cavity film segment is provided with an opening communicating with the outside, and the distal opening of the second inner stent communicates with the opening; the support strength of the first inner stent is greater than that of the second inner stent.

24. The covered stent according to claim 23, characterized in that, The first inner stent and the second inner stent include a mesh body, the wire diameter of the mesh body of the first inner stent is greater than that of the second inner stent, and / or the mesh density of the first inner stent is greater than that of the second inner stent.

25. The covered stent according to claim 24, wherein The axial length of the first inner stent at least at the connection part with the aneurysm cavity film segment is greater than or equal to the axial length of the second inner stent at the connection part with the aneurysm cavity film segment.

26. The covered stent according to claim 25, wherein, The proximal end of the first inner stent is provided with a first proximal inclined opening, the proximal end of the second inner stent is provided with a second proximal inclined opening, and the first proximal inclined opening and the second proximal inclined opening are arranged oppositely.

27. The covered stent according to claim 26, wherein The distal end of the first embedded stent is provided with a first distal bevel and is parallel to the first proximal bevel, and the distal end of the second embedded stent is provided with a flat mouth; or the distal end of the second embedded stent is provided with a second distal bevel and is parallel to the second proximal bevel.

28. The covered stent according to claim 26, wherein, The covered stent further includes a transition section connected between the proximal section and the aneurysmal cavity covered section, and the transition section is provided with a transition stent.

29. The covered stent according to claim 28, wherein, The proximal end of the transition stent is flush with the proximal end of the aneurysmal cavity covered section, and both sides of the distal end of the transition stent are respectively flush with the first proximal bevel and the second proximal bevel.

30. The covered stent according to claim 28, wherein, The distal end of the proximal section includes a special-shaped wave loop, and the distal end of the special-shaped wave loop includes a plurality of distal high waves, and the distal high waves extend to the transition section to form the transition stent.

31. The covered stent according to claim 23, wherein, The first embedded stent and the distal section are integrally formed.

32. The covered stent according to claim 23, wherein, The proximal ports and / or distal ports of the first embedded stent and the second embedded stent are provided with radiopaque markers.

33. The covered stent according to any one of claims 1-32, characterized in that, The proximal section is provided with a plurality of hook members, the hook members are arranged along the axial direction of the proximal section, and at least two of the hook members are provided at the same axial position.

34. A stent delivery system, characterized in that, Comprising the covered stent according to any one of claims 1-33 and a delivery device, the delivery device includes a hanging rod, the hook member is connected to the hanging rod, and after connection, at least a part of the covered stent is in a compressed state.

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