Vascular stent

Abstract

Disclosed in the present invention is a vascular stent. The vascular stent comprises a main stent provided with a main lumen; the main stent comprises a proximal section, a distal section, and a middle section located between the proximal section and the distal section and extending axially; a recessed portion is provided on the middle section; a supporting structure which protrudes outwards relative to the recessed portion is provided above the recessed portion; and at least part of the supporting structure is degradable. According to the vascular stent of the present invention, at least part of the supporting structure at the top of the vascular stent is configured to be degradable. In this way, the initial mechanical supporting effect of a recess section is guaranteed while retaining the overall structure. In a long term, the material of this part can be automatically absorbed after a certain time, thereby reducing the restraint and compression on a branch stent, reducing the occupancy of the main cavity space, and reducing the stimulation effect on the inner wall of a blood vessel.

Description

Vascular stents Technical Field

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

[0002] Aortic aneurysm and aortic dissection are diseases that currently pose a serious threat to human life. If not actively treated, the aortic aneurysm and dissection will continue to grow and eventually rupture, causing serious complications and death. With the increasing number of patients with hypertension, hyperlipidemia and hyperglycemia, the incidence of aortic aneurysm and aortic dissection is also increasing significantly.

[0003] Traditional open surgical treatments for aortic aneurysms and aortic dissections are characterized by significant trauma, high mortality, prolonged operative times, high rates of postoperative complications, and high surgical difficulty. Endovascular treatment, however, offers minimal trauma, fewer postoperative complications, shorter operative times, and reduced surgical difficulty, making it the primary treatment for these conditions. By implanting a covered stent graft in the aorta, the vascular lesion is isolated outside the graft, restricting blood flow to the interior of the graft, thereby protecting the vessel.

[0004] As shown in FIG1 , the support coils of the existing aortic covered stent 100' are generally made of memory metal alloy, so that during surgery, a guide wire can be used to select the brachiocephalic artery, the left common carotid artery, and the left subclavian artery through the internal branches. However, after the stent is implanted, it will be affected by the restraint of the support coils and will occupy the corresponding main cavity space. The support coils will also have a negative squeezing effect on the implanted branch stents. In particular, as shown at A' in FIG1 , the branch stent 203' corresponding to the left subclavian artery is easily affected by the support coils and is constrained and squeezed after implantation, which is not conducive to the blood circulation of the left subclavian artery. In addition, the presence of the support coils will cause long-term irritation to the inner wall of the blood vessel or cause reverse tearing of the inner wall of the blood vessel.

[0005] Summary of the Invention

[0006] Based on this, the present invention proposes a vascular stent to at least solve some of the above technical problems.

[0007] To achieve this object, the present invention adopts the following technical solutions:

[0008] The present invention provides a vascular stent, comprising a main body stent with a main lumen, the main body stent comprising a proximal segment, a distal segment, and an intermediate segment extending axially between the proximal segment and the distal segment, the intermediate segment being provided with a recessed portion, a support structure being provided above the recessed portion, and at least a portion of the support structure being degradable.

[0009] In one embodiment, the support structure is provided with a branch channel radially passing through the support structure, and the branch channel can be passed through by a branch stent. At least a partial edge of the branch channel is degradable, so that the branch channel can expand after at least partial degradation. The expanded branch channel can reduce the squeezing of the branch stent passing through it.

[0010] In one embodiment, the branch channels at least include a right branch channel disposed close to the distal end of the support structure; and / or a left branch channel disposed close to the proximal end of the support structure.

[0011] In one embodiment, the support structure comprises a mesh structure having a plurality of grids, wherein one or more of the grids are used to form the branch channels.

[0012] In one embodiment, the support structure includes a main support layer that is at least partially degradable, the main support layer is formed using support filaments, and the support filaments include at least degradable first support filaments.

[0013] In one embodiment, the first degradable support wire is fully degradable or partially degradable; when the first support wire is partially degradable, the first support wire is a multi-layer structure arranged from the inside to the outside, and the first support wire includes a non-degradable inner core located in the innermost layer and a degradable covering layer located in the outermost layer.

[0014] In one embodiment, the degradable first support filaments form the main support layer.

[0015] In one embodiment, the support filaments further include non-degradable second support filaments, and the degradable first support filaments and the non-degradable second support filaments together form the main support layer.

[0016] In one embodiment, the first support filaments form a degradable layer, the second support filaments form a non-degradable layer, and the degradable layer and the non-degradable layer are arranged opposite to each other in the same layer;

[0017] Alternatively, the first supporting filaments form a degradable layer, the second supporting filaments form a non-degradable layer, and the degradable layer and the non-degradable layer are adjacent and connected at adjacent locations;

[0018] Alternatively, the first support filaments and the second support filaments are interspersed in the same layer, so that the first support filaments form multiple degradable layers, the second support filaments form a non-degradable layer, and the multiple degradable layers are dispersed in the non-degradable layer in the same layer.

[0019] In one embodiment, during the process of forming the main support layer, the support wires have an intersection point formed by the intersection of multiple support wires, and the multiple support wires at the intersection point are connected, and / or overlapped, and / or hooked.

[0020] In one embodiment, when the plurality of support wires overlap at an intersection, the plurality of support wires at the intersection may be connected by a fixing member, and the fixing member is used to radially constrain the plurality of support wires to prevent them from radially separating from each other;

[0021] And / or, when the plurality of support filaments include the first support filament and the second support filament, and the first support filament and the second support filament overlap at an intersection, the first support filament at the intersection is located above the second support filament;

[0022] And / or, when the plurality of support wires include the first support wire and the second support wire, and the first support wire and the second support wire are overlapped at the intersection, the radial thickness of the first support wire at least at the intersection is greater than the radial thickness of the second support wire, and a cross channel is provided at the intersection of the first support wire for the second support wire to pass through.

[0023] In one embodiment, when the support wires at the intersection are connected by a fixing member, the fixing member is provided with a first sliding channel extending along a first preset direction and a second sliding channel extending along a second preset direction, wherein one of the support wires can slide relative to the fixing member along the first preset direction, wherein the other support wire can slide relative to the fixing member along the second preset direction, and the first preset direction and the second preset direction are the pre-movement directions of the support wires when the vascular stent is compressed or self-expanded;

[0024] And / or, when the first supporting wire is provided with a cross channel for the second supporting wire to pass through, the cross channel is provided with a preset length along the extension direction of the first supporting wire.

[0025] In one embodiment, when multiple support wires are hooked, an axially extending elastic connector is provided between the support wires at the hooking locations, and the ends of the elastic connector are respectively connected to the hooking portions of the multiple support wires, and the elastic connector is used to elastically pull the multiple support wires closer to each other.

[0026] In one embodiment, the first support wire can be formed by 3D printing, and / or injection molding, and / or metal cutting, and / or weaving; and / or when the support wire includes the second support wire, the second support wire can be formed by metal cutting, and / or weaving.

[0027] In one embodiment, the support structure further includes a non-degradable local support layer, which is stacked with the main support layer from inside to outside, and the local support layer is opposite to the degradable layer formed by the first support filament in the main support layer.

[0028] In one embodiment, the main support layer includes a mesh structure. In a naturally expanded state, the main support layer includes a first mesh area and a second mesh area connected to the first mesh area in the circumferential direction; the first mesh area includes a plurality of columns of cross units formed by overlapping a plurality of spaced first-direction support wires and a plurality of spaced second-direction support wires; the second mesh area includes at least one column of hook units, each column of the hook units includes one or more axially arranged hook units, and the hook units include a first hook member and a second hook member, and the first hook member and the second hook member in at least some of the hook units are roughly hooked to each other along the axial direction, or, the first hook member and the second hook member in at least some of the hook units are roughly separated from each other along the axial direction to form a gap, or, the first hook member and the second hook member in at least some of the hook units are non-hooked against each other.

[0029] In one embodiment, the degradable material includes a degradable polymer material and / or a degradable metal material.

[0030] In one embodiment, the degradable polymer material includes at least one of polylactic acid, polyglycolic acid, polysuccinate, poly(β-hydroxybutyrate), polyβ-alkanoate, polycaprolactone, polyethylene adipate, polylactic acid-glycolic acid copolymer, polyhydroxybutyrate valerate copolymer, polyvinyl alcohol, polyethylene glycol, polyvinyl pyrrolidone, starch, cellulose, polyethylene oxide, pectin, collagen, chitosan, dextran, chitin and derivatives of the above polymers, or is made of a copolymer formed by copolymerizing at least two of the monomers forming the above materials; and / or,

[0031] The degradable metal material includes at least one of zinc, magnesium, iron, zinc-based alloy, magnesium-based alloy, and iron-based alloy.

[0032] The vascular stent of the present invention makes at least part of the supporting structure at the top of the vascular stent degradable. This method ensures the initial mechanical support of the groove section without giving up the function of the overall structure. In the long term, this part of the material can be self-absorbed after a certain period of time, thereby reducing the restraint and squeezing of the branch stent, reducing the encroachment on the main cavity space and the stimulation to the inner wall of the blood vessel. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] FIG1 is a schematic structural diagram of an existing aortic stent graft implanted;

[0034] FIG2 is a schematic structural diagram of an exemplary vascular stent according to the present invention;

[0035] FIG3 is a schematic structural diagram of an exemplary support structure in a vascular stent according to the present invention;

[0036] FIG4 is a schematic diagram of another structure of a support structure in an exemplary vascular stent of the present invention;

[0037] FIG5 is a schematic diagram showing the connection between the support structure and the edge of the recessed portion in an exemplary vascular stent of the present invention;

[0038] Figure 6(a) is a schematic diagram of the tiling of a main support layer, Figure 6(b) is a schematic diagram of the connection and tiling of the main support layer and the edge of the recessed portion of Figure 6(a), and Figure 6(c) is a schematic diagram of the degradable layer in the main support layer of Figure 6(b) after degradation;

[0039] FIG7( a ) is a schematic diagram of another main support layer being laid out, FIG7( b ) is a schematic diagram of the connection and laying out of the main support layer and the edge of the recessed portion of FIG7( a ), and FIG7( c ) is a schematic diagram of the degradable layer in the main support layer of FIG7( b ) after degradation;

[0040] FIG8( a ) is a schematic diagram of another main support layer being laid out, FIG8( b ) is a schematic diagram of the connection and laying out of the main support layer and the edge of the recessed portion of FIG8( a ), and FIG8( c ) is a schematic diagram of the degradable layer in the main support layer of FIG8( b ) after degradation;

[0041] FIG9( a ) is a schematic diagram of another main support layer being laid out, FIG9( b ) is a schematic diagram of the connection and laying out of the main support layer and the edge of the recessed portion of FIG9( a ), and FIG9( c ) is a schematic diagram of the degradable layer in the main support layer of FIG9( b ) after degradation;

[0042] FIG10( a ) is a schematic diagram of another main supporting layer being laid out, wherein a fixing member is provided in the main supporting layer; FIG10( b ) is a schematic diagram of the connection and laying out of the main supporting layer and the edge of the recessed portion of FIG10( a ); and FIG10( c ) is a schematic diagram of the degradable layer in the main supporting layer of FIG10( b ) after degradation;

[0043] FIG11( a ) is a schematic top view of the fixing member in FIG10( a ), FIG11( b ) is a schematic side view of the fixing member in FIG10( a ), FIG11( a1 ) is a schematic view of a support wire passing through the fixing member in FIG11( a ), and FIG11( b1 ) is a schematic view of a support wire passing through the fixing member in FIG11( b );

[0044] FIG12( a ) is a schematic diagram of another main support layer being laid out, FIG12( b ) is a schematic diagram of the connection and laying out of the main support layer and the edge of the recessed portion of FIG12( a ), and FIG12( c ) is a schematic diagram of the degradable layer in the main support layer of FIG12( b ) after degradation;

[0045] FIG13( a ) is a schematic diagram of another main supporting layer being laid out, wherein an elastic connector is provided in the main supporting layer; FIG13( b ) is a schematic diagram of the connection between the main supporting layer of FIG13( a ) and the edge of the recessed portion; and FIG13( c ) is a schematic diagram of the degradable layer in the main supporting layer of FIG13( b ) after degradation;

[0046] Figure 14(a) is a schematic diagram of the tiling of a main supporting layer and a local supporting layer, Figure 14(b) is a schematic diagram of the connection tiling of the main supporting layer and the local supporting layer and the edge of the recessed portion in Figure 14(a), and Figure 14(c) is a schematic diagram of the main supporting layer and the local supporting layer in Figure 14(b) after degradation of the degradable layer in the main supporting layer;

[0047] Figure 15(a) is a schematic diagram of another type of tiling of a main supporting layer and a local supporting layer, Figure 15(b) is a schematic diagram of the connection tiling of the main supporting layer and the local supporting layer with the edge of the recessed portion in Figure 15(a), and Figure 15(c) is a schematic diagram of the main supporting layer and the local supporting layer in Figure 15(b) after degradation of the degradable layer in the main supporting layer;

[0048] FIG16 is a schematic diagram of a multilayer structure when the degradable first support filament is partially degradable;

[0049] FIG17 is a schematic diagram of another multi-layer structure when the degradable first support filament is partially degradable. DETAILED DESCRIPTION

[0050] In order to make the objectives, technical solutions, and advantages of the present invention more clearly understood, exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0051] It should be understood that the terms used herein are for the purpose of describing specific example embodiments only and are not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms "one", "an" and "said" as used herein may also be meant to include plural forms. The terms "comprise", "include", "contain" and "have" are inclusive and therefore specify the presence of stated features, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, steps, operations, elements, parts, and / or combinations thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring them to be performed in the specific order described or illustrated, unless the order of execution is clearly indicated. It should also be understood that additional or alternative steps may be used.

[0052] 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.

[0053] 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.

[0054] To more clearly describe the structure of this application, the terms "proximal" and "distal" are defined herein as commonly used in the field of interventional medicine. Specifically, "distal" refers to the end from which blood flows out, and "proximal" refers to the end from which blood flows in. For example, after stent implantation, blood flows from the proximal end to the distal end of the stent. "Axial" refers to the longitudinal direction of the stent, and "radial" refers to the direction perpendicular to the "axial" direction.

[0055] In general, as shown in FIG2 , the present invention provides a vascular stent 100. The vascular stent 100 includes a main stent 10 having a main lumen 10a. The main stent 10 includes a proximal section 11, a distal section 12, and an intermediate section 13 extending axially between the proximal section 11 and the distal section 12. The intermediate section 13 is provided with a recessed portion 131. A support structure 20 is provided above the recessed portion 131. At least a portion of the support structure 20 is degradable. To enhance support, the support structure 20 is convex relative to the recessed portion 131. The vascular stent 100 of the present invention ensures the initial mechanical support of the recessed section without sacrificing the overall structure. In the long term, the material of the recessed section can be self-absorbed over time, thereby reducing the constraint and compression of the branch stent, reducing the encroachment on the main lumen space, and reducing the irritation to the inner wall of the blood vessel.

[0056] As shown in FIG2 , the vascular stent 100 of the present invention includes a main stent 10 and a support structure 20. The main stent 10 is a self-expanding hollow tubular structure with openings at both ends, defining a main lumen 10a therein. In other embodiments, the vascular stent 100 further includes an embedded branch 14 disposed within the main stent 10, with the main lumen 10a of the main stent 10 communicating with the inner lumens of the embedded branch 14.

[0057] Exemplarily, the main support 10 includes a main support portion and a main coating. The main coating can be provided on the inner surface and / or outer surface of the main support portion, or the main coating can be provided on part of the inner surface of the main support portion and part of the outer surface. The main support 10 can be divided into a proximal section 11, a distal section 12 and an intermediate section 13 extending axially between the proximal section 11 and the distal section 12. The proximal section 11 includes a tubular proximal support portion and a proximal main coating. The proximal main coating can be applied to the inner side and / or outer side of the proximal support portion by suturing, bonding, hot melting or the like. The proximal support portion includes a plurality of axially spaced main wave coils. The distal section 12 includes a tubular distal support portion and a distal main coating. The distal main coating can also be applied to the inner side and / or outer side of the distal support portion by suturing, bonding, hot melting or the like. The distal support portion includes a plurality of axially spaced main wave coils. A recessed portion 131 is provided on the middle section 13, and the support structure 20 is located above the recessed portion 131 of the middle section 13 and preferably protrudes relative to the recessed portion 131. The middle section 13 includes a middle main body coating and a middle support portion (which may be omitted in other embodiments). The inner cavity formed by the middle main body coating is connected to the inner cavity formed by the proximal main body coating and the inner cavity formed by the distal main body coating. The edge of the support structure 20 is at least partially fixedly connected to the edge 13a of the recessed portion by suturing, bonding, hot melting, etc., and a gap (or called a gap, cavity) is formed between the support structure 20 and the outer surface of the middle section 13, and the gap can be connected to the inner cavity of the embedded branch 14. The support structure 20 in the present invention is at least partially degradable, that is, partially or completely degradable. The degradable refers to degradability that can be achieved at least in the body, and its degradation rate can be controlled by adjusting the degradable material and structure as needed. When a branch stent is needed to bridge a branch vessel, the branch stent can pass through the support structure 20 and communicate with the embedded branch 14. During the branch reconstruction process, the support structure 20, which has supporting properties, provides initial mechanical support. Blood flow can enter the gap between the support structure 20 and the middle section 13 through the embedded branch 14, and then pass through the support structure 20 to enter the branch vessel, thus avoiding the problem of prolonged ischemia in the branch vessel during the branch reconstruction process. For twisted lumens, especially those with a small true lumen, the gap between the support structure 20 and the middle section 13 provides a more stable operating space during surgery, avoiding compression of the operating space due to compression of the middle unit by the lumen. At the same time, after the branch stent is implanted, at least a portion of the degradable support structure 20 is degraded and absorbed, and the surrounding area is expanded, which can effectively reduce the long-term compression of the branch stent, long-term irritation to the vessel wall, and later invasion of the main lumen space.

[0058] The "membrane" in the present invention can isolate liquids to a certain extent, and can be made of a polymer material with good biocompatibility, such as polytetrafluoroethylene (PTFE) and polyethylene terephthalate (PET).

[0059] As shown in Figure 2, illustratively, the support structure 20 is roughly arc-shaped (the state when the vascular stent 100 is in natural expansion and expansion), and the central angle corresponding to the projection of the support structure 20 on the radial plane is less than or equal to 120 degrees, so that the support structure 20 has good radial supporting force and ensures that there is sufficient space in the middle section 13 for blood to flow through, while making the radial compression size of the middle section 13 more appropriate.

[0060] In order to facilitate the branch stent to pass through the support structure 20, the support structure 20 is provided with a branch channel that radially penetrates the support structure 20. The branch channel can be used for the branch stent to pass through. At least a partial edge of the branch channel is degradable, so that the branch channel can expand after at least partial degradation. The expanded branch channel can reduce the squeezing of the branch stent passing through it. Exemplarily, referring to Figures 2 to 5, the support structure 20 can be a planar structure or a mesh structure. As shown in Figure 3, the support structure 20 is a planar structure, and the branch channel can be a perforation a provided on the planar structure. Exemplarily, the peripheral a1 area of ​​the perforation a is degradable. When the degradation in the peripheral a1 area is absorbed, the perforation a expands to avoid continuous squeezing of the branch stent passing through the perforation a. As shown in Figures 2, 4 and 5, the support structure 20 is a mesh structure. A grid b is formed on the mesh support structure 20. The grid b can be used as a branch channel for the branch stent to pass through. Exemplarily, as shown in FIG4 , at least part of the grid b is a branch channel for the branch stent to pass through, and at least part of the peripheral grid b1 constituting the grid b is degradable. When the peripheral grid b1 is degraded and absorbed, the grid b expands, thereby avoiding continuous squeezing of the branch stent passing through the grid b. It should be noted that when there are multiple grids, the size and formation of the multiple grids can be set as needed, and their shapes can be the same or different, and the sizes can be the same or different. One or more grids can be selected as branch channels. As shown in FIG5 , during the manufacturing process, the prefabricated support structure 20 is combined with the main support 10. When combined, the peripheral edge of the support structure 20 can be fixed relative to the edge 13a of the recessed portion 131. The fixing method includes but is not limited to sewing the coating at the edge 13a. The fixed support structure 20 is convex relative to the recessed portion and is roughly arc-shaped.

[0061] In order to facilitate communication between the embedded branches 14 and the branched blood vessels located on the side of the recessed portion 131, the branch channels are generally arranged near the axial side of the support structure 20. For example, when one or two embedded branches 14 are connected to the proximal side of the main stent 10, the branch channels can be arranged near the proximal side of the support structure 20. In this case, one or two branch channels can be arranged near the proximal side. When one or two embedded branches 14 are connected to the distal side of the main stent 10, the branch channels can be arranged near the distal side of the support structure 20. In this case, one or two branch channels can be arranged near the distal side. When embedded branches are arranged on both the proximal and distal sides of the main stent 10, branch channels can be arranged on both the proximal and distal sides of the support structure 20. As shown in Figure 2, in this embodiment, the proximal side of the main stent 10 is connected to two embedded branches 14, and the distal side is connected to one embedded branch 14. Two branch channels are arranged near the proximal side of the support structure 20, and one branch channel is arranged near the distal side, corresponding to each other.

[0062] 2 to 13, the support structure 20 includes a main support layer 21 that is at least partially degradable. When the main support layer 21 is a mesh structure, as an embodiment of the mesh structure main support layer 21 of the present invention, the mesh shape of FIG6 (a) is used as an example for explanation. The main support layer 21 is in a flattened state (this is the natural state when the support layer 21 is not connected to the main support 10), and the main support layer 21 includes a first mesh area and a second mesh area connected to the first mesh area in the circumferential direction; the first mesh area includes a plurality of spaced support wires arranged in the first direction. The second mesh area includes at least one column of hooking units, each column of hooking units includes one or more hooking units arranged axially, and the hooking units include a first hooking member and a second hooking member. At least part of the hooking units have the first hooking member and the second hooking member roughly hooked with each other along the axial direction, or, at least part of the hooking units have the first hooking member and the second hooking member roughly separated from each other along the axial direction to form a gap, or, at least part of the hooking units have the first hooking member and the second hooking member non-hookedly abutted against each other.

[0063] The main support layer 21 of the mesh structure is formed by support filaments 211 , and the support filaments 211 at least include degradable first support filaments 211 a .

[0064] For the sake of clarity, in the process of annotating the accompanying drawings, the dotted lines represent degradable and the solid lines represent non-degradable. Referring to Figures 6(a) to 6(c), in one embodiment, the support filaments 211 only include degradable first support filaments 211a, which form the main support layer 21, that is, the main support layer 21 is entirely formed by the degradable first support filaments 211a, which is a single-layer structure, and the main support layer 21 is degradable. The edge of the main support layer 21 formed by the degradable first support filaments 211a is at least partially fixed relative to the edge 13a of the recessed portion. After the main support layer 21 is degraded and absorbed, the first support filaments 211a inside the edge 13a of the recessed portion are degraded, and the orifice c corresponding to the embedded branch 14 is no longer blocked. When the branch stent is connected to it, it will no longer be constrained and squeezed by the support filaments.

[0065] 7(a) to 15(c), in another embodiment, the support filaments 211 include not only degradable first support filaments 211a but also non-degradable second support filaments 211b. That is, the degradable first support filaments 211a and the non-degradable second support filaments 211b together form the main support layer 21. In other words, the main support layer 21 of this embodiment is not completely degradable, but rather partially degradable. This local degradation avoids constraint and extrusion, while the undegraded portions provide continuous support.

[0066] The degradable first support filament 211a of the present invention is fully or partially degradable. As shown in Figures 16 and 17 , when the first support filament 211a is partially degradable, the first support filament 211a comprises a multi-layer structure arranged from the inside out, including an innermost, non-degradable core 211a11 and an outermost, degradable coating 211a12. The inner core 211a11 is non-degradable and made of a non-degradable material, while the coating 211a12 is degradable and made of a degradable material. For example, the degradable coating 211a12 can be applied to the inner core 211a11. Alternatively, in another embodiment, as shown in Figure 17 , an adhesive layer 211a13 is further included between the inner core 211a11 and the coating 211a12, which can securely attach the coating 211a12 to the inner core 211a11 via the adhesive layer 211a13. The multi-layered structure of the degradable first support filament 211a in this embodiment, with its non-degradable filament serving as the inner core, significantly enhances the radial support performance of the mesh cover. Furthermore, its radial support force is evenly distributed, minimizing damage to the vascular lining. After the outer coating degrades and absorbs, the diameter of the support coils decreases, thereby achieving the therapeutic goal of alleviating compression on the supra-arch branch stent and the vascular lining. When the degradable first support filament 211a and the non-degradable second support filament 211b together form the main support layer 21, at least the following implementation methods exist:

[0067] Method 1, referring to Figures 7(a) to 7(c), the first support wire 211a forms a degradable layer 211A, and the second support wire 211b forms a non-degradable layer 211B. The degradable layer 211A and the non-degradable layer 211B are arranged relative to each other in the same layer, and the relative positions include interval relative positions or abutment relative positions. The degradable layer 211A formed by the first support wire 211a and the non-degradable layer 211B formed by the second support wire 211b are relatively independent. It can be understood that the relative areas of their distribution can be arranged according to actual needs. The figure is only an exemplary illustration. In this method, the fixation of the degradable layer 211A and the non-degradable layer 211B can be selected by fixing them separately to the main support 10 to form the main support layer 21, or they can be fixed relative to each other by a connector and then fixed to the main support 10. It should be noted that the fixing method is not limited to this. For example, the edges of the degradable layer 211A formed by the degradable first support wire 211a and the non-degradable layer 211B formed by the non-degradable second support wire 211b are at least partially fixed relative to the edge 13a of the recessed portion. After the degradable layer 211A is degraded and absorbed, the opening c corresponding to the embedded branch 14 is no longer blocked, and the branch stent will no longer be constrained and squeezed by the support wire when it is connected to it.

[0068] Mode two, with reference to Figures 8 (a) to 8 (c), the first support filament 211a forms a degradable layer 211A, and the second support filament 211b forms a non-degradable layer 211B. The degradable layer 211A and the non-degradable layer 211B are adjacent and connected at adjacent locations, that is, the degradable layer 211A formed by the first support filament 211a and the non-degradable layer 211B formed by the second support filament 211b are adjacent and connected. The connection can be directly connected as shown in Figure 8 (a), or it can be connected by other connectors (not shown). In this embodiment, the two have been formed relatively fixed, so the edge of the degradable layer 211A formed by the degradable first support filament 211a and the non-degradable layer 211B formed by the non-degradable second support filament 211b can be relatively fixed to the edge 13a of the recessed portion. After the degradation of the degradable layer 211A is absorbed, the orifice c corresponding to the embedded branch 14 is no longer blocked, and will no longer be subject to the constraint of the support filament when the branch stent is connected thereto.

[0069] Method three, as shown in Figures 9(a), 10(a), 12(a) and 13(a), the first supporting wire 211a and the second supporting wire 211b are interspersed in the same layer, so that the first supporting wire 211a forms a plurality of degradable layers 211A, and the second supporting wire 211b forms a non-degradable layer 211B. The plurality of degradable layers 211A are dispersed in the non-degradable layer 211B in the same layer, that is, the degradable layer 211A formed by the first supporting wire 211a is not limited to one place, but is dispersed in multiple areas. Under this method, not only can the area of ​​the degradable layer 211A be flexibly set according to needs, but the overall support of the support structure 20 can also be ensured as much as possible. In the present embodiment, the two have formed relatively fixed, and the edge of the degradable layer 211A formed by the degradable first supporting filament 211a and the non-degradable layer 211B formed by the non-degradable second supporting filament 211b can be relatively fixed at least in part with the edge 13a of the recessed portion. After the degradation of the degradable layer 211A is absorbed, the corresponding orifice c of the embedded branch 14 is no longer blocked, and when the branch stent is connected to it, it will no longer be subject to the constraint of the supporting filament and squeezed. It should be noted that the "dispersion" of the present embodiment is only the definition carried out relative to the region where its various parts are located, and does not mean that a plurality of degradable layers 211A must be independent of each other. The degradable layers of a plurality of dispersions can be independent of each other, or can be connected. Exemplary, for example, if a first supporting filament 211a is used to intersperse and set (such as interspersed and braided), the degradable layers 211A of each dispersion are actually connected.

[0070] Furthermore, it should be noted that the term "same layer" as used herein does not necessarily limit the support filaments 211 forming the support structure to a single layer. During the configuration process, as needed, the support filaments 211 may be stacked or hooked. During design, one, two, or more of the aforementioned methods may be selected based on actual needs. These methods may be freely combined as long as they do not conflict, and any combination thereof falls within the scope of protection of the present invention.

[0071] Exemplarily, with reference to Figures 9 (a) to 9 (c), the first support filament 211a forms a degradable layer 211A, and the second support filament 211b forms a non-degradable layer 211B. The degradable layer 211A and the non-degradable layer 211B are interlaced and connected at the relative edges, that is, the degradable layer 211A formed by the first support filament 211a and the non-degradable layer 211B formed by the second support filament 211b are dispersed and interlaced at the edges. Such an interlaced connection at the edges can ensure both the reliability of the connection and the support requirements. In this embodiment, the two have been relatively fixed, so the edges of the degradable layer 211A formed by the degradable first support filament 211a and the non-degradable layer 211B formed by the non-degradable second support filament 211b can be relatively fixed to the edge 13a of the recessed portion. After the degradable layer 211A is degraded and absorbed, the orifice c corresponding to the embedded branch 14 is no longer blocked, and when the branch stent is connected thereto, it will no longer be constrained and squeezed by the support filament.

[0072] In order to ensure the effective support of the vascular stent 100 in the early stage, it is generally required that the support wires 211 have an intersection formed by the intersection of multiple support wires 211 in the process of forming the main support layer 21, and the multiple support wires 211 at the intersection are connected, and / or overlapped, and / or hooked at the intersection. That is, the support wires 211 at the intersection adopt any one or more methods of connection, overlap and hooking. As shown in Figure 8 (a), the support wires at the intersection H1 are directly connected, while the support wires at the intersection H2 in Figure 10 (a) are overlapped (similar to a cross), and the support wires at the intersection H3 are hooked. Among them, the intersection method between the support wires at the intersection can be selected arbitrarily.

[0073] Since the first support wire 211 is degradable, its support is relatively weak. During the self-expansion process of the vascular stent 100, in order to ensure the establishment of the groove space in the initial stage of implantation, whether the first support wire 211 can be fully expanded is crucial to the implantation process. In view of this, the present invention proposes the following further solution.

[0074] In one embodiment, as shown in Figures 10(a) to 10(c), when multiple support filaments 211 overlap at an intersection, the multiple support filaments 211 at the intersection can be connected by a fixing member 30. The fixing member 30 is used to radially constrain the multiple support filaments 211 to prevent radial separation. For example, as shown in Figure 10(a), the support filaments 211 at the intersection H2 are two support filaments 211. Of course, the support filaments 211 here can all be degradable first support filaments 211a, or can include both degradable first support filaments 211a and non-degradable second support filaments 211b. The fixing member 30 connects the two support filaments 211, allowing the support filaments 211 to expand and expand together during the self-expansion and deployment of the vascular stent 100 after compression. This avoids the difficulty in deploying the first support filaments 211a made of degradable material due to the poor self-elasticity, thereby effectively ensuring the initial support of the vascular stent 100. The fixing member 30 of this embodiment is degradable. In this embodiment, the two are relatively fixed, and the edges of the degradable layer 211A formed by the degradable first support wire 211a and the non-degradable layer 211B formed by the non-degradable second support wire 211b can be at least partially fixed relative to the edge 13a of the recessed portion. After the degradable layer 211A and the fixing member 30 are degraded and absorbed, the opening c corresponding to the embedded branch 14 is no longer blocked, and the branch stent will no longer be constrained and squeezed by the support wire when it is connected to it.

[0075] Furthermore, because the vascular stent 100 needs to be compressed into the delivery device by external force before implantation, and it is desired that it can self-expand after release, therefore, in conjunction with Figures 10(a) and 11, when the support wires 211 at the intersection are connected by the fixing member 30, the fixing member 30 is provided with a first sliding channel 31 extending along a first predetermined direction S1 and a second sliding channel 32 extending along a second predetermined direction S2. One support wire 211a can slide relative to the fixing member 30 along the first predetermined direction S1, and the other support wire 211b can slide relative to the fixing member along the second predetermined direction S2. The first predetermined direction S1 and the second predetermined direction S2 are the pre-set directions of movement of the support wires 211 when the vascular stent 100 is compressed or self-expands. Typically, the first predetermined direction S1 and the second predetermined direction S2 are the extension directions of the support wires 211 at the intersection. For example, as shown in Figures 10(a) and 11, the first support wire 211a slides along the first preset direction S1 in the first sliding channel 31, and the second support wire 211b slides along the first preset direction S2 in the second sliding channel 32, but the fixing member 30 always radially constrains the first support wire 211a and the second support wire 211b together. When the vascular stent 100 is compressed or self-expanded, the two support wires 211 connected to the fixing member 30 are jointly expanded, so that the first support wire 211a is expanded as the second support wire 211b is expanded.

[0076] In another embodiment, when the plurality of support wires 211 include a first support wire 211a and a second support wire 211b, and the first support wire 211a and the second support wire 211b overlap at an intersection, to ensure that the first support wire 211a can be effectively deployed, the first support wire 211a at the intersection is positioned above the second support wire 211b. During deployment, the second support wire 211b, which has better self-expanding properties, can provide support to the first support wire 211a positioned thereon, effectively ensuring smooth deployment and support of the first support wire 211a, while avoiding the problem of occupying internal operating space if the first support wire 211a is not fully deployed. In this manner, since the first support wire 211a is positioned above the self-expanding second support wire 211b, even without the provision of the fixing member 30, the first support wire 211a can be deployed with the support of the second support wire 211b.

[0077] In another embodiment, as shown in Figures 12(a) to 12(c), when the plurality of support wires 211 include a first support wire 211a and a second support wire 211b, and the first support wire 211a and the second support wire 211b are overlapped at the intersection, that is, they overlap at the intersection H4 as shown in Figure 12(a), the radial thickness h of the first support wire 211a at least at the intersection is greater than the radial thickness d of the second support wire 211b (when the second support wire 211b is columnar, it is its diameter), and a cross channel 211a1 is provided at the intersection of the first support wire 211a for the second support wire 211b to pass through. In this embodiment, as shown in FIG12( a), at the intersection H4, the second support filament 211b passes through the first support filament 211a, so that the self-expanding second support filament 211b is at least partially covered by the first support filament 211a. During the deployment of the first support filament 211a, the self-expanding second support filament 211b provides outward support to the first support filament 211a, thereby effectively ensuring that the first support filament 211a is smoothly deployed and provides support. In addition, another advantage of this embodiment is that if the degradable layer 211A formed by the first support filament 211a is formed by 3D printing or injection molding, then the method for passing the second support filament 211b through the cross channel 211a1 of the first support filament 211a is easy to implement, and the process is relatively simple. For example, after the second braided filament 211b is braided, the first support filament 211a is then 3D printed or injection molded to wrap the second support filament 211b within it at the intersection. Alternatively, the first support wire 211a may be pre-stacked with a cross channel 211a1 during 3D printing or injection molding, and then wound around the cross channel 211a1 when weaving the second support wire 211b. Further, in this embodiment, in order to avoid the first support wire 211a being too thick at the intersection, the cross channel 211a1 may be semi-arc-shaped, requiring only the partial coating of the second support wire 211b. In this embodiment, the first support wire 211a and the second support wire 211b are interlaced in the same layer, and multiple degradable layers 211A are dispersed in the non-degradable layer 211B. The edge of the degradable layer 211A formed by the degradable first support wire 211a and the non-degradable layer 211B formed by the non-degradable second support wire 211b is at least partially fixed to the edge 13a of the recessed portion. After the degradable layer 211A is degraded and absorbed, the orifice c corresponding to the embedded branch 14 is no longer blocked, and will no longer be constrained and squeezed by the support wire when the branch stent is connected thereto.

[0078] Continuing with FIG12( a ), when the first support filament 211 a is provided with a cross channel 211 a 1 through which the second support filament 211 b passes, the cross channel 211 a 1 has a predetermined length w along the extension direction of the first support filament 211 a . This predetermined length w ensures that the second support filament 211 b has sufficient room to maneuver when the stent 100 is compressed or self-expanded, thereby facilitating smooth compression and expansion of the support structure 20 and providing effective and stable support.

[0079] In another embodiment, as shown in Figures 13(a) to 13(c), when multiple support wires 211 are hooked, that is, hooked at the intersection H3 in Figure 13(a), an axially extending elastic connector 40 is provided between the support wires 211 at the hooking location. The ends of the elastic connector 40 are respectively connected to the hooking portions of the multiple support wires 211. The elastic connector 40 is used to elastically pull the multiple support wires 211 closer to each other. Similarly, the elastic connector 40 can form good connectivity, ensuring that the support wires 211 are radially compressed or expanded simultaneously when the vascular stent 100 is compressed or self-expanded, and giving the support wires 211 connected thereto a certain range of movement. Among them, the elastic connector 40 of this embodiment is degradable. In this embodiment, the first support wire 211a and the second support wire 211b are interspersed in the same layer, and multiple degradable layers 211A are dispersed in the non-degradable layer 211B in the same layer. The edges of the degradable layer 211A formed by the degradable first support wire 211a and the non-degradable layer 211B formed by the non-degradable second support wire 211b are at least partially fixed to the edge 13a of the recessed portion. After the degradable layer 211A and the elastic connecting member 40 are degraded and absorbed, the orifice c corresponding to the embedded branch 14 is no longer blocked, and will no longer be constrained and squeezed by the support wire when the branch stent is connected to it.

[0080] The degradable first support filaments 211a of the present invention can be formed by 3D printing, injection molding, metal cutting, and / or weaving. The non-degradable second support filaments 211b of the present invention can be formed by metal cutting and / or weaving. It should be noted that any one or more of the above methods can be selected for formation. Of course, this is not limiting.

[0081] Referring to Figures 14(a) and 15(a), in order to further ensure the support performance of the partially degradable support structure 20, the support structure 20 further includes a non-degradable partial support layer 22. Specifically, the support structure 20 includes a main support layer 21 and a partial support layer 22. The partial support layer 22 and the main support layer 21 are stacked from the inside out, with the main support layer 21 located on the outside and the partial support layer 22 located on the inside. The main support layer 21 is located above the partial support layer 22, and the partial support layer 22 is opposite the degradable layer 211A formed by the first support filament 211a within the main support layer 21. This double-layer inside-outside arrangement allows the partial support layer 22 located inside to effectively support the degradable layer 211A located outside. Furthermore, this method provides greater flexibility in arranging the support structure 20, reduces manufacturing process requirements, and increases efficiency.

[0082] Among them, in Figures 14(a) to 14(c), the support structure 20 includes a main support layer 21 and a local support layer 22. The main support layer 21 is formed as a whole by a degradable first support wire 211a, which is located on the outside; the local support layer 22 is formed by a non-degradable elastic wave ring, and the local support layer 22 is arranged near the middle of the inner layer of the main support layer 21. The edges of the degradable layer 211A formed by the degradable first support wire 211a and the local support layer 22 are at least partially fixed to the edge 13a of the recessed portion. After the degradable layer 211A located on the outside is degraded and absorbed, the orifice c corresponding to the embedded branch 14 is no longer blocked, and will no longer be constrained and squeezed by the support wire when the branch stent is connected to it, while the local support layer 22 cannot be degraded and continues to provide support.

[0083] In Figures 15(a) to 15(c), the support structure 20 includes a main support layer 21 and a local support layer 22. The main support layer 21 includes a degradable first support filament 211a and a non-degradable second support filament 211b. The first support filament 211a forms a degradable layer 211A, and the second support filament 211b forms a non-degradable layer 211B. The degradable layer 211A and the non-degradable layer 211B are interlaced and connected at relative edges, that is, the degradable layer 211A formed by the first support filament 211a and the non-degradable layer 211B formed by the second support filament 211b are dispersed and interlaced at the edges. The local support layer 22 is formed by a non-degradable elastic wave ring. The local support layer 22 is arranged near the distal side and is located in the inner layer of the main support layer 21. The edges of the degradable layer 211A formed by the degradable first support wire 211a, the non-degradable layer 211B formed by the non-degradable second support wire 211b, and at least part of the edge of the local support layer 22 are all relatively fixed to the edge 13a of the recessed portion. After the degradable layer 211A located on the outside is degraded and absorbed, the orifice c corresponding to the embedded branch 14 is no longer blocked, and when the branch stent is connected to it, it will no longer be constrained and squeezed by the support wire. The local support layer 22 cannot be degraded and continues to provide support.

[0084] The degradable material of the present invention includes a degradable polymer material and / or a degradable metal material.

[0085] Exemplary degradable polymer materials include polylactic acid, polyglycolic acid, polysuccinate, poly(β-hydroxybutyrate), polyβ-alkanoate, polycaprolactone, polyethylene adipate, polylactic acid-glycolic acid copolymer, polyhydroxybutyrate valerate copolymer, polyvinyl alcohol, polyethylene glycol, polyvinyl pyrrolidone, starch, cellulose, polyethylene oxide, pectin, collagen, chitosan, dextran, chitin, and at least one of their derivatives, or copolymers formed by copolymerizing at least two of the monomers forming the above materials; degradable metal materials include at least one of zinc, magnesium, iron, zinc-based alloys, magnesium-based alloys, and iron-based alloys. It should be noted that degradable materials are not limited to the above.

[0086] The vascular stent of the present invention makes at least part of the supporting structure at the top of the vascular stent degradable. This method ensures the initial mechanical support of the groove section without giving up the function of the overall structure. In the long term, this part of the material can be self-absorbed after a certain period of time, thereby reducing the restraint and squeezing of the branch stent, reducing the encroachment on the main cavity space and the stimulation to the inner wall of the blood vessel.

[0087] Based on the above-mentioned overall structure of the vascular stent 100, the structure of the present invention will be briefly illustrated below in conjunction with specific drawings and embodiments. The structure of the main stent 10 in the vascular stent 100 is referred to above and will not be repeated here. The following embodiments will mainly illustrate the specific implementation of the support structure 20. It should be noted that the various embodiments can be optionally combined:

[0088] Example 1

[0089] 6(a) to 6(c), in this embodiment, the support structure 20 is a mesh structure. The mesh support structure 20 is formed using degradable first support filaments 211a. That is, the main support layer 21 is entirely formed from the degradable first support filaments 211a (the dotted lines represent the degradable first support filaments 211a). It is a single-layer structure, and the main support layer 21 is degradable. The degradable support structure of this embodiment can be made of an absorbent material with good biocompatibility. The main support layer 21 can be absorbed in the body in the long term, and the degradation rate is controllable. It has excellent processability, mechanical strength, and a controllable degradation rate.

[0090] Its unique characteristics include sufficient radial support strength to support the groove space, facilitating the selection of internal branch guidewires, while also providing excellent toughness to reduce irritation and damage to the vessel wall. Compared to traditional vascular stents, the main support layer 21 is fully absorbable, effectively reducing long-term compression of the branch stent, long-term irritation to the vessel wall, and subsequent encroachment on the main lumen space.

[0091] Example 2

[0092] 8(a) to 8(c), in this embodiment, the support structure 20 is a mesh structure (different from the mesh structure of Example 1), and Example 2 adopts a spaced degradable structure. The mesh support structure 20 of Example 2 is woven together by a degradable first support filament 211a and a non-degradable second support filament 211b (the dotted line is the degradable first support filament 211a, and the solid line is the non-degradable second support filament 211b).

[0093] In this embodiment, the support wave coil woven by the second non-degradable support wire of the memory metal alloy has better radial support force than the support wave coil woven by the first degradable support wire. If the support force of the support wave coil is too small, it may cause insufficient groove space, especially the part adjacent to the embedded branch. Insufficient radial support force will affect the selection of the internal branch guide wire and increase the difficulty of the operation. This embodiment adopts a staggered braiding structure of degradable and non-degradable materials. With the help of the mechanical properties of the non-degradable material, it has better support than Example 1. In addition, this embodiment partially selects degradable materials to reduce the existence area of ​​long-term support wave coils, which can effectively reduce the stimulation to the inner wall of the blood vessel and the downward squeezing and encroachment on the main cavity. After degradation, the restraint and squeezing of the branch stent are reduced.

[0094] Example 3

[0095] Referring to Figures 9(a) to 9(c), this embodiment is similar to the mesh structure of Example 1, differing in that the main support layer 21 of this embodiment is woven from a degradable first support filament 211a and a non-degradable second support filament 211b, employing a connected degradable and non-degradable structure. The proportion of the degradable portion determines the number of degradable units based on the actual size of the patient's aorta. The degradable portion, indicated by the dashed line, is adjacent to the internal branch of the left subclavian artery. The dashed line represents the degradable first support filament 211a, and the solid line represents the non-degradable second support filament 211b. The wire pressing is as shown in the figure, with breaks indicating the wire is at the bottom. When the first and second support filaments 211a and 211b overlap at their intersection, the degradable first support filament 211a at the intersection is positioned above the non-degradable second support filament 211b. The pressing directions of the two adjacent locations are opposite to ensure structural and morphological stability. This embodiment can ensure the radial support effect of the support wave ring, and the adjacent support wave rings of the left subclavian artery branch stent can be degraded, which can more effectively or completely solve the negative squeezing effect on the branch stent.

[0096] Example 4

[0097] 10(a) to 10(c), this embodiment is similar to the mesh structure of embodiment 1 and embodiment 3, and this embodiment adopts a spaced absorbable structure. The rest of the structure and working principle are the same as embodiment 1. After absorption, the absorbable layer of embodiment 3 is susceptible to external force at the tip portion on the right side (refer to FIG9(c)), which may cause damage to the inner wall of the blood vessel. In this embodiment, there is no single-filament sharp-angle structure after degradation (refer to FIG10(c)), which avoids damage. This embodiment can not only effectively solve the extrusion problem after implantation of the left subclavian branch stent, but also has better radial support performance and more uniform radial support strength. The proportion of non-absorbable units is smaller.

[0098] At the same time, in order to enhance the supporting performance, a cross fixing member 30 is added above the non-degradable first supporting wire 211a to increase the structural stability.

[0099] Example 5

[0100] Referring to Figures 13(a) to 13(c), this embodiment is similar to the mesh structures of Examples 1, 3, and 4, differing in that an elastic connector 40 is added at the hooking position to enhance support performance. When the support coils are horizontal, the elastic connector 40 is in a tense state. After stent release, the support coils correspond to the aortic arch and bend as the stent expands during implantation. To restore the support coils to their natural state, the elastic connector 40 pulls on the two wires, reducing the hooking distance between the wires and thereby strengthening the support of the support coils.

[0101] Example 6

[0102] 12(a) to 12(c), this embodiment is similar to the mesh structure of embodiment 1, embodiment 3, embodiment 4 and embodiment 5. This embodiment is based on embodiment 4 and adopts the structure shown in FIG12(a). Considering that the brachiocephalic trunk and the left common carotid branch stent are less likely to be squeezed and deformed by the support wave ring than the left subclavian branch stent, but the support wave ring at this position requires sufficient radial support force to support the blood vessel wall to ensure the groove space, this embodiment retains the adjacent parts of the brachiocephalic trunk and the left common carotid branch and still uses traditional non-absorbable materials. There needs to be enough space adjacent to the brachiocephalic trunk / left common carotid branch for selecting the brachiocephalic trunk and the left common carotid branch, and the support requirements for the material are relatively high. This embodiment uses non-absorbable materials to retain the original radial support performance and ensure that there is sufficient space to select branches. Among them, the number of stent legs and the proportion of absorbable units can be adjusted according to the actual patient's aortic condition.

[0103] Example 7

[0104] 14(a) to 14(c), this embodiment adopts a double-layer structure and adds a local support layer 22. The support structure 20 includes a main support layer 21 and a local support layer 22. The local support layer 22 and the main support layer 21 are stacked from the inside to the outside, that is, the main support layer 21 is located on the outside, the local support layer 22 is located on the inside, and the main support layer 21 is located above the local support layer 22. The local support layer 22 is two corrugated rings, lining the bottom of the absorbable main support layer 21. Its position is located in the middle of the absorbable main support layer 21 and does not interfere with the implantation of the branch stent. The double-layer design improves the radial support of the absorbable part. The absorbable unit accounts for a large proportion. After absorption, only two corrugated rings remain, which is conducive to the recovery of the vascular endothelium. In addition, its radial support force is evenly distributed and is not easy to damage the inner wall of the blood vessel.

[0105] Example 8

[0106] 8(a) to 8(c), in this embodiment, the first supporting wire 211a forms a degradable layer 211A, and the second supporting wire 211b forms a non-degradable layer 211B. The degradable layer 211A and the non-degradable layer 211B are adjacent to each other and connected at adjacent locations. In this embodiment, the absorbable unit and the non-absorbable unit are connected at the connection point: the connection method is shown in the figure. An arc-shaped tube is provided at the end of the absorbable wire for passing the non-absorbable wire, which is a movable connection. The connecting tube and the non-absorbable wire can move relative to each other within a certain range, thereby increasing the grid space, facilitating the selection of the internal branch with the guide wire, and reducing the squeezing effect on the branch stent after implantation, and increasing the proportion of the absorbable unit.

[0107] Example 9

[0108] As shown in Figures 15(a) to 15(c), this embodiment adopts a double-layer structure with the addition of a local support layer 22. The support structure 20 comprises a main support layer 21 and a local support layer 22. The local support layer 22 is stacked with the main support layer 21 from the inside out, with the main support layer 21 located on the outside and the local support layer 22 located on the inside, with the main support layer 21 located above the local support layer 22. The end of the non-absorbable wire support wave coil is connected to the half-wave coil, forming an integrated structure, enhancing the support performance of the terminal wire and the structural stability of the non-absorbable portion. This optimizes the sharp angle structure of Example 3.

[0109] The vascular stent of the present invention makes at least part of the supporting structure at the top of the vascular stent degradable. This method ensures the initial mechanical support of the groove section without giving up the function of the overall structure. In the long term, this part of the material can be self-absorbed after a certain period of time, thereby reducing the restraint and squeezing of the branch stent, reducing the encroachment on the main cavity space and the stimulation to the inner wall of the blood vessel.

[0110] The technical features of the above embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of the present invention.

[0111] The above embodiments merely illustrate several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A vascular stent, characterized in that: It comprises a main body support with a main cavity, the main body support comprises a proximal section, a distal section, and an intermediate section extending axially between the proximal section and the distal section, the intermediate section is provided with a recessed portion, a support structure is provided above the recessed portion, and at least part of the support structure is degradable.

2. The vascular stent according to claim 1, characterized in that: The support structure is provided with a branch channel which radially penetrates the support structure, and the branch channel can be passed through by a branch stent. At least a partial edge of the branch channel is degradable, so that the branch channel can expand after at least partial degradation. The expanded branch channel can reduce the squeezing of the branch stent passing through it.

3. The vascular stent according to claim 2, characterized in that: The branch channels at least include a right branch channel disposed close to the distal end side of the support structure; and / or a left branch channel disposed close to the proximal end side of the support structure.

4. The vascular stent according to claim 2, characterized in that: The support structure includes a mesh structure having a plurality of grids, wherein one or more of the grids are used to form the branch channels.

5. The vascular stent according to claim 1, characterized in that: The support structure comprises a main support layer which is at least partially degradable, wherein the main support layer is formed by support filaments, and the support filaments comprise at least degradable first support filaments.

6. The vascular stent according to claim 5, characterized in that: The first degradable support filaments form the main support layer.

7. The vascular stent according to claim 5, characterized in that: The support filaments further include non-degradable second support filaments, and the degradable first support filaments and the non-degradable second support filaments together form the main support layer.

8. The vascular stent according to claim 7, characterized in that: The first supporting filaments form a degradable layer, the second supporting filaments form a non-degradable layer, and the degradable layer and the non-degradable layer are arranged opposite to each other in the same layer; Or, the first supporting filaments form a degradable layer, the second supporting filaments form a non-degradable layer, and the degradable layer and the non-degradable layer are adjacent and connected at the adjacent position; Or, the first supporting wire and the second supporting wire are interlaced in the same layer, so that the first supporting wire The second supporting filaments form a plurality of degradable layers, the second supporting filaments form a non-degradable layer, and the plurality of degradable layers are dispersed in the non-degradable layer in the same layer.

9. The vascular stent according to any one of claims 6 to 8, characterized in that: In the process of forming the main supporting layer, the supporting wires have intersection points formed by the intersection of multiple supporting wires, and the multiple supporting wires at the intersection points are connected, and / or overlapped, and / or hooked.

10. The vascular stent according to claim 9, characterized in that: When the plurality of support wires overlap at the intersection, the plurality of support wires at the intersection may be connected by a fixing member, and the fixing member is used to radially constrain the plurality of support wires to prevent them from being radially separated from each other; And / or, when the plurality of support wires include the first support wire and the second support wire, and the first support wire and the second support wire overlap at an intersection, the first support wire at the intersection is located above the second support wire; And / or, when the plurality of support wires include the first support wire and the second support wire, and the first support wire and the second support wire are overlapped at the intersection, the radial thickness of the first support wire at least at the intersection is greater than the radial thickness of the second support wire, and a cross channel is provided at the intersection of the first support wire for the second support wire to pass through.

11. The vascular stent according to claim 10, characterized in that: When the support wires at the intersection are connected by a fixing member, a first sliding channel extending along a first preset direction and a second sliding channel extending along a second preset direction are provided on the fixing member, wherein one of the support wires can slide relative to the fixing member along the first preset direction, wherein the other support wire can slide relative to the fixing member along the second preset direction, and the first preset direction and the second preset direction are the pre-movement directions of the support wires when the vascular stent is compressed or self-expanded; And / or, when the first supporting wire is provided with a cross channel through which the second supporting wire can pass, the cross channel is provided with a preset length along the extending direction of the first supporting wire.

12. The vascular stent according to claim 9, characterized in that: When multiple support wires are hooked, an axially extending elastic connector is provided between the support wires at the hooking position, and the ends of the elastic connector are respectively connected to the hooking portions of the multiple support wires, and the elastic connector is used to elastically pull the multiple support wires closer to each other.

13. The vascular stent according to claim 6 or 7, characterized in that: The support structure also includes a non-degradable local support layer, which is stacked with the main support layer from inside to outside, and the local support layer is opposite to the degradable layer formed by the first support filament in the main support layer.

14. The vascular stent according to claim 5, characterized in that: The main support layer includes a mesh structure. In a naturally unfolded state, the main support layer includes a first mesh area and a second mesh area connected to the first mesh area in a circumferential direction; the first mesh area includes a plurality of columns of cross units formed by overlapping a plurality of spaced first-direction support wires and a plurality of spaced second-direction support wires; the second mesh area includes at least one column of hook units, each column of the hook units includes one or more axially arranged hook units, the hook units include a first hook member and a second hook member, at least some of the hook units have the first hook member and the second hook member roughly axially hooked to each other, or, at least some of the hook units have the first hook member and the second hook member roughly axially separated from each other to form a gap, or, at least some of the hook units have the first hook member and the second hook member non-hookingly abutted against each other.

15. The vascular stent according to claim 5, characterized in that: The first degradable support wire is fully degradable or partially degradable; when the first support wire is partially degradable, the first support wire is a multi-layer structure arranged from the inside to the outside, and the first support wire includes a non-degradable inner core located in the innermost layer and a degradable covering layer located in the outermost layer.

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