Double-layer stent and weaving method thereof

Abstract

The invention relates to a double-layer stent which comprises a knitting main body, the knitting main body is of a hollow cylinder structure formed by interweaving knitting units arranged in the first knitting direction and knitting units arranged in the second knitting direction, and the knitting main body is of a double-layer structure and comprises a knitting outer layer and a knitting inner layer; each layer is formed by interweaving weaving units in two weaving directions, and at least one weaving unit of the weaving outer layer and at least one weaving unit of the adjacent weaving outer layer form a connecting thread, so that the potential stent layering risk of the double-layer weaving stent is reduced while high radial supporting force, high metal coverage rate, low shortening rate and blood flow guiding capability are ensured, and the stability of the double-layer weaving stent is improved. Knitting units are rotationally interwoven at the local connecting wire strands of the stent, the original wire pressing structure is changed, the deformation resisting capacity near interlayer connecting points is improved, the weaving units which are near the interlayer connecting points and generate displacement due to friction force can be driven to rapidly return to the original positions, and the risk of local layering of the stent is resisted.

Description

Technical Field

[0001] The present application relates to the technical field of medical devices, and in particular to a double-layer stent and a weaving method thereof. Background Art

[0002] Minimally invasive interventional surgery is a common treatment for intracranial aneurysms. For intracranial aneurysms, the commonly used treatment techniques include coil packing, covered stent implantation, stent-assisted coil packing, blood flow guidance device placement and other methods. For large and giant saccular aneurysms, wide-necked aneurysms, fusiform and dissecting aneurysms, the surgical treatment process is relatively complicated, with high intraoperative and postoperative complication rates and high postoperative recurrence rates. Therefore, the use of more traditional coil or stent-assisted coil packing technology for treatment has the problem of long intraoperative time consumption, difficulty in completely blocking the aneurysm neck, and incomplete aneurysm occlusion; covered stents are difficult to use in curved blood vessels in most cases, and are difficult to put in place, and are not suitable for siphon bends and above; after the blood flow guidance device is placed at the neck of the aneurysm, it first reduces the impact of blood flow on the aneurysm wall by changing the direction of blood flow in the parent artery, and finally forms new endothelial cells on the stent surface and the aneurysm neck, achieving complete occlusion and healing of the aneurysm and reconstruction of the parent artery. In comparison, blood flow guidance devices are more suitable for this type of disease. The shortening of the blood flow guiding device is usually long, which places high demands on the surgeon's release and positioning, because the tight sealing of the aneurysm neck is crucial for aneurysm treatment. The emergence of double-layer braided stents is of great help in reducing the shortening of the braided stent, reducing the difficulty of releasing and positioning the blood flow guiding device, and shortening the operation time.

[0003] Ordinary double-layer stents will be subjected to external forces such as compression, pushing, and stretching during the process of assembly, transportation, and release, and interlayer separation is very likely to occur. The fundamental reason is that the braided stent is made of two groups of braided wires with different rotation directions, and the two layers of the stent are not smooth surfaces. The existence of friction causes the displacement of the braided wires after the force cannot be restored in time, and the two layers of the stent are delaminated. At the same time, the mesh uniformity of the stent will also be reduced, affecting the treatment effect. Summary of the invention

[0004] In view of this, the present application proposes a double-layer stent and a weaving method thereof to avoid the phenomenon of interlayer separation of the double-layer stent.

[0005] According to one aspect of the present application, there is provided a double-layer stent, comprising: a braided body;

[0006] The braided body comprises a braiding unit arranged along a first braiding direction and a braiding unit arranged along a second braiding direction, and the braiding units in the two braiding directions are interwoven to form a hollow cylindrical structure;

[0007] Wherein, the braiding unit is a single wire or multiple wires, which are formed into a spring, strand, rope or other structure by twisting, winding or other methods in advance or during the braiding process;

[0008] Wherein, the braided main body comprises at least a braided outer layer and a braided inner layer, and each layer is interwoven by braiding units in two braiding directions;

[0009] At least one braided wire of the braided inner layer is cross-woven with at least one braided wire of the braided outer layer adjacent thereto to form a connecting wire strand.

[0010] In a possible implementation, in the connecting wire strands, the weaving units of the weaving outer layer in the weaving wire strands have the same weaving direction as or different weaving directions as the weaving units of the weaving inner layer.

[0011] In a possible implementation, two braiding units in the connecting wire strands are rotated and braided in a clockwise or counterclockwise direction to form an interlayer connection point.

[0012] In a possible implementation, at the same axial position of the stent, there is at least one interlayer connection point formed by at least one braiding unit of the braided outer layer in the connecting wire strand and at least one braiding unit of the braided inner layer in the circumferential direction of the stent.

[0013] In a possible implementation, at the same axial position of the stent, the braided body is provided with at least one interlayer connection point along the circumferential direction to form an interlayer connection wire group;

[0014] Two adjacent interlayer connecting wire groups are spaced apart by a preset distance along the axial length direction of the braided main body.

[0015] In a possible implementation manner, the interlayer connection points of different interlayer connection wire groups are distributed at the same or different circumferential positions along the axial projection of the braided body.

[0016] In a possible implementation, the diameters of the braided wires along the first braiding direction and the braided wires along the second braiding direction are both within a range of 20 micrometers to 100 micrometers;

[0017] The braiding unit is made of a single material or a mixture of two or more materials. The braiding unit is made of a material with shape memory effect or X-ray opaque performance, or a material with both of the above properties, such as nickel-titanium wire, cobalt-chromium wire, platinum wire, nickel-titanium-platinum core wire, cobalt-chromium-platinum core wire, etc.

[0018] The stent is woven by the braiding units of the same material and structure, or is woven by a mixture of the braiding units of different materials and structures;

[0019] In a possible implementation, both ends of the braided wires of the connecting wire strands are loose structures, partially closed wire structures, or fully closed wire structures;

[0020] A weaving method, using a double-layer stent, comprises the following steps;

[0021] When weaving starts or ends, the total number of threads w involved in weaving is evenly divided into n weaving thread groups, the number of threads in each weaving thread group is w / n, and n can be 3, 4, 6, 8, 10, or 12;

[0022] The ε group is further divided into two bundles, where ε is a natural number greater than 0, ε≤η;

[0023] The two equally divided weaving units rotate in the same direction or in opposite directions to form a stable yarn bundle, and then the two yarn bundles are bound together in parallel to form a yarn collection group.

[0024] In a possible implementation, an end portion of the braided body is sleeved with an X-ray-proof noble metal hollow tube.

[0025] In a possible implementation, the end of the braided body is fully or partially wound, and the adjacent braided wires with different rotation directions form a winding group;

[0026] The wire collecting group and the rewinding group can be distributed in staggered layers.

[0027] The beneficial effects of the double-layer stent of the embodiment of the present application are as follows: the stent of the braided main body contains a special braiding structure, which greatly reduces the potential risk of stent delamination of the double-layer braided stent while ensuring high radial support force, high metal coverage, low shortening rate and better blood flow guidance ability, and has certain advantages for clinical use in the treatment of bleeding aneurysm diseases. Specifically, by rotating and interweaving the braided wires at the local connecting wire strands of the stent, the ability to resist deformation near the interlayer connection points is increased. After the external force is applied, these interlayer connection points have greater rigidity and can drive the braided wires displaced by friction near the interlayer connection points to quickly return to their original positions, resisting the risk of local delamination of the stent, and the interlayer connection groups distributed in various parts of the double-layer braided stent further increase the overall ability of the stent to resist delamination.

[0028] Other features and aspects of the present application will become apparent from the following detailed description of exemplary embodiments with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate exemplary embodiments, features, and aspects of the present application and, together with the description, serve to explain the principles of the present application.

[0030] Figure 1 A schematic diagram showing the structure of a double-layer bracket according to an embodiment of the present application;

[0031] Figure 2 A schematic diagram showing the cross-sectional structure of a double-layer bracket according to an embodiment of the present application is shown;

[0032] Figure 3 (a) shows a schematic diagram of the same-direction connected wire strands, Figure 3 (b) shows a schematic diagram of reverse connection of silk strands;

[0033] Figure 4 (a) is a schematic diagram showing the different directions of the connecting wire strands α = 180 degrees, Figure 4 (b) is a schematic diagram showing the anisotropically connected strands α=360 degrees;

[0034] Figure 5 (a) is a schematic diagram showing the same direction connection of wire strands α = 180 degrees, Figure 4 (b) is a schematic diagram showing the same direction connection of the wire strands α = 360 degrees;

[0035] Figure 6 A schematic diagram showing the structure of a wire collection group of a double-layer stent according to an embodiment of the present application is shown;

[0036] Figure 7 A schematic diagram showing the closed fixation of the wire collection group of the double-layer stent according to an embodiment of the present application is shown;

[0037] Figure 8 A schematic diagram showing the closed end of the full wire collection group of the double-layer stent according to an embodiment of the present application is shown;

[0038] Fig. 9 A schematic axial diagram of a fully wrapped closed end of a double-layer stent according to an embodiment of the present application is shown;

[0039] Fig.10 A schematic diagram showing staggered distribution of closed ends of a double-layer stent according to an embodiment of the present application is shown;

[0040] Fig.11 A schematic diagram showing a braided structure of a non-interlayer connection structure of a double-layer stent according to an embodiment of the present application;

[0041] Fig.12 A partial enlarged schematic diagram of a double-layer stent according to an embodiment of the present application is shown;

[0042] Fig.13 Another schematic diagram showing a double-layer stent according to an embodiment of the present application;

[0043] Fig.14 A schematic diagram showing the cross-weaving units of the double-layer stent according to an embodiment of the present application is shown. DETAILED DESCRIPTION

[0044] Various exemplary embodiments, features and aspects of the present application will be described in detail below with reference to the accompanying drawings. The same reference numerals in the accompanying drawings represent elements with the same or similar functions. Although various aspects of the embodiments are shown in the accompanying drawings, the drawings are not necessarily drawn to scale unless otherwise specified.

[0045] Among them, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention or simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0046] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0047] The word “exemplary” is used exclusively herein to mean “serving as an example, example, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments.

[0048] In addition, in order to better illustrate the present application, numerous specific details are given in the following specific embodiments. It should be understood by those skilled in the art that the present application can also be implemented without certain specific details. In some examples, methods, means, components and circuits well known to those skilled in the art are not described in detail in order to highlight the subject matter of the present application.

[0049] See also Figure 1 and Figure 2The double-layer stent of the embodiment of the present application includes: a braided main body 100, wherein the braided main body 100 includes braided wires arranged along a first braiding direction and braided wires arranged along a second braiding direction, and the braided wires in the two braiding directions are interwoven with each other to form a hollow cylindrical structure, wherein the braided main body 100 includes at least a braided outer layer 110 and a braided inner layer 120, each layer is interwoven with braided wires in two braiding directions, and at least one braided wire of the braided inner layer 120 is cross-woven with at least one braided wire of the braided outer layer 110 adjacent thereto to form a connecting wire strand, thereby increasing the ability to resist deformation near the interlayer connection point, changing the original pressure line structure of the stent, and improving the stability of the relative position of the two layers of the stent, and can drive the braided unit displaced due to friction near the interlayer connection point to quickly return to its original position, thereby resisting the risk of local delamination of the stent.

[0050] In this embodiment, the stent of the braided body 100 contains a special braided structure, which greatly reduces the potential risk of stent delamination of the double-layer braided stent while ensuring high radial support force, high metal coverage, low shortening rate and better blood flow guidance ability, and has certain advantages for clinical use in the treatment of bleeding aneurysm diseases. Specifically, by rotating and interweaving the braided wires at the local connecting wire strands of the stent, the ability to resist deformation near the interlayer connection point 301 is increased. After the external force is applied, these interlayer connection points 301 have greater rigidity and can drive the braided wires displaced by friction near the interlayer connection point 301 to quickly return to their original positions, resisting the risk of local delamination of the stent, and the interlayer connection groups distributed in various parts of the double-layer braided stent further increase the overall ability of the stent to resist delamination.

[0051] In one specific embodiment, see Figure 2 The braided body 100 is a double-layer braided structure, including a braided outer layer 110 and a braided inner layer 120. The braided inner layer 120 is provided with 2m braided wires, and the braided wires of the braided wires 130 of the hand direction 1 and the braided wires 140 of the hand direction 2 are m in length, and the braided outer layer 110 is provided with 2n braided wires, and the braided wires of the braided wires 130 of the hand direction 1 and the braided wires 140 of the hand direction 2 are n in length, and the total number of braided wires w=2(m+n), wherein m+n≥6, and both m and n are natural numbers greater than 0.

[0052] In this specific embodiment, see Figure 3 and Figure 4 The connecting wire strands may be same-direction connecting wire strands composed of braided wires with the same rotation direction, or different-direction connecting wire strands composed of braided wires with different rotation directions.

[0053] In one specific embodiment, see Figure 4 and Figure 5The two braided wires in the connecting wire strand are rotated and interwoven together in a clockwise or counterclockwise direction to form an interlayer connection point 301, wherein the rotation angle α=C*180°, and C is a natural number greater than 0.

[0054] In this specific embodiment, at least one outer braided wire 111 and one inner braided wire 121 are included. Among them, there are four braiding connection methods of the outer braided wire 111 and the inner braided wire 121, including: connecting the wire strands in different directions and α is 180 degrees, connecting the wire strands in different directions and α is 360 degrees, connecting the wire strands in the same direction and α is 180 degrees, and connecting the wire strands in the same direction and α is 360 degrees. In this way, different ways of connecting the outer braided wire 111 with the inner braided wire 121 can be selected according to the usage scenario, while ensuring the deformation resistance of the braided body, and can be bent in place.

[0055] Furthermore, in the braided wire strands, when the braiding direction of the braided wires of the inner layer is the same as that of the braided wires of the outer layer, in the braided wire strands, the braided wires of the outer layer are woven along the braiding direction of the braided wires of the inner layer, and are woven into the braided inner layer 120. In the braided wire strands, the braided wires of the inner layer are woven along the braiding direction of the braided wires of the outer layer, and are woven into the braided outer layer 110, and the number of exchanges is at least once, and the angle between the braided wires woven out of the braided inner layer 120 and the braided wires woven out of the braided inner layer 120 is 20°<α<180.

[0056] Among them, in the braided wire strands, the braiding directions of the inner layer braiding wires and the outer layer braiding wires are different. In the braided wire strands, the braiding wires of the outer layer are woven along the braiding direction of the inner layer braiding wires and woven into the braided inner layer 120. In the braided wire strands, the braiding wires of the inner layer are woven along the braiding direction of the outer layer braiding wires and woven into the braided outer layer 110.

[0057] In one specific embodiment, see Fig.12 , the braiding pitch of the stent is P. Within one braiding pitch, all braided wires rotate 360° along the circumference of the stent. At the same axial position, the braided body 100 is circumferentially provided with r interlayer connection points 301 to form an interlayer connection group, where 1≤r≤min(m,n). Within one pitch P, the stent has a total of t interlayer connection groups in the axial direction. Depending on the operation, the spacing between the layer connection groups along the axial direction of the stent is different, which can bring different effects. Specifically, when the spacing between two adjacent interlayer connection groups is small, the flexibility of this area is reduced. When the spacing between two adjacent interlayer connection groups is large, the flexibility of this area is improved. Therefore, the position can be different. The braided wires of the braided outer layer of the stent and the braided wires of the braided inner layer form different numbers of braided wire strands, and the number of interlayer connection points 301 formed by cross-weaving is different.

[0058] In this specific embodiment, see Fig.12 The r interlayer connection points 301 in an interlayer connection wire group can be completely composed of connection wire strands in the same direction or connection wire strands in different directions, or can also include connection wire strands in the same direction and connection wire strands in different directions.

[0059] In this specific embodiment, the number of connecting wire points contained in the plurality of interlayer connecting wire groups distributed at different axial positions of the braided main body 100 may be the same or different.

[0060] In one specific embodiment, see Figure 6 , Figure 7 and Fig.12 At the non-interlayer connection structure 302, the angles formed by the braided wires of the hand-1 braided wires 130 and the hand-2 braided wires 140 are respectively 20-160°. Figure 6 The braided wires do not overlap with each other and are arranged in a staggered manner. The braided wires of the braided inner layer 120 and the braided outer layer 110 have no interlayer connection point 301. The two-layer braided structure of the braided body 100 can be any regular braided structure such as 1-1, 1-2, 2-2, or a combination thereof.

[0061] In one specific embodiment, the braided wires of the braided body 100 can be made of materials with shape memory properties such as nickel-titanium, cobalt-chromium, etc., alone or in combination.

[0062] In this specific embodiment, the braided body 100 can be made of nickel-titanium tubes containing platinum or cobalt-chromium-nickel tubes containing platinum throughout the body, in order to achieve a whole-body development effect.

[0063] In this specific embodiment, the braided main body 100 can be prepared by mixing nickel-titanium wire or cobalt-chromium wire with platinum wire.

[0064] Among them, see Fig.11 The relationship between the number x of the nickel-titanium wire or the cobalt-chromium wire and the number y of the platinum wire of the braided body 100 is x=q*y, where q is a positive integer, q≤48.

[0065] In one specific embodiment, the outer diameter of the braided body 100 is 1.5-7 mm, and the length is 10-70 mm.

[0066] In one specific embodiment, participating Figure 8 , Fig. 9 , Fig.10 and Fig.12 The braided body 100 having interlayer connection points 301 may have loose braided wire heads at both ends, or a partially closed or fully closed structure formed by binding the radiopaque metal hollow tube 400 and the braided wire together by winding, welding or mechanical crimping.

[0067] In one specific embodiment, see Fig.14 The braided inner layer 120 is arranged crosswise with the braided 110, through Fig.14 In the middle, the depth of the color is marked.

[0068] In one of the specific embodiments, through the above content, when the braided body 100 is a multi-layer structure, that is, the number of braided layers L>2, the different layers of the braided layers are Li from the inside to the outside, and the number of braided wire heads corresponding to the different layers of the braided layers are Ni, where i is a natural number greater than 0, and the total number of wire heads of the stent w=ΣNi.

[0069] In this specific embodiment, the connecting wire strands of the interlayer connection point 301 can be composed of the innermost braided wire of the braided main body 100 and the outermost braided wire of the braided main body 100, or can be composed of the braided wires of adjacent braided layers. The connecting wire strands can be unidirectional or unidirectional connecting wire strands. During the braiding process, the two braided wires in the connecting wire strands are rotated and interwoven in a clockwise or counterclockwise direction to form an interlayer connection point 301, wherein the rotation angle α=C*180°, and C is a natural number greater than 0.

[0070] In this specific embodiment, see Fig.13 The interlayer connection of the multi-layer braided main body 100 can be a cross-layer connection, which is composed of the braided wire of the innermost layer of the braided main body 100 and the braided wire of the outermost layer of the braided main body 100 to form a cross-layer connection point.

[0071] In this specific embodiment, the interlayer connection of the multi-layer braided body 100 can be a layer-by-layer connection, which is composed of the braided wires of adjacent braided layers to form a layer-by-layer connection. L1 and L2 form an interlayer connection point 301D1^2, L2 and L3 form an interlayer connection point 301D2^3, and so on, until the braided wires of the outermost layer of the braided body 100 participate in the interlayer connection, and D1^2, D2^3,...Di-1^i together constitute an interlayer connection matrix.

[0072] In this specific embodiment, within a braiding pitch P, all braiding wires rotate 360° along the circumference of the stent, and r cross-layer connection points or interlayer connection matrices or a combination thereof are provided circumferentially of the braided body 100 to form an interlayer connection group, where 1≤r≤min(Ni / 2), and within a pitch P, the braided body 100 has a total of t interlayer connection groups axially, where 1≤t≤w / 2.

[0073] In a specific embodiment, the braided wire heads at both ends of the stent may be loose, or a partially closed or fully closed structure may be formed by binding the radiopaque metal hollow tube and the braided wire together by winding, welding or mechanical crimping.

[0074] In this specific embodiment, the selection can be made by different methods of use and different braiding numbers. Specifically, when the braided wire heads at both ends of the stent are in a loose state, the stent saves time and effort during the manufacturing process and shortens the working hours. When the braided wire heads at both ends of the stent are in a coiled state, since there are no loose wire heads, they will not damage the inner wall of the blood vessel inside the blood vessel, thus avoiding irritation to the blood vessel. In addition, part of the state can be loose and part can be coiled. The welding method can directly weld the loose wire heads at both ends of the stent. The mechanical crimping method is similar to the welding method, and the loose wire heads at both ends of the stent can be directly fixed by crimping.

[0075] Among them, the two braided layers inside and outside the stent adopt innovative closed wire collection technology at both ends to achieve fully closed or partially closed structural optimization. The core of this technology lies in the fine distribution of wire heads. At the beginning and end of the braiding process, all the wire heads involved in the braiding (the total number is w) are first evenly divided into several (denoted as η, the optional values ​​are 3, 4, 6, 8, 10, 12, etc.) braided wire groups, and the number of wire heads in each group is equal, all w / η. Subsequently, for a specific number of groups (denoted as ε, a natural number greater than 0 and less than or equal to η), a more detailed division is performed, that is, each group of wire heads is divided into two, forming two bundles of sub-wire bundles. They can rotate in the same direction or in opposite directions. Through this delicate dynamic balance, a stable and compact wire bundle structure is formed. , The two carefully processed wire bundles are bound together in parallel to form a closed wire collection group. This process not only reduces the possibility of scattered wire heads, but also enhances the structural strength of the two ends of the stent through physical binding, so that the entire stent has higher stability and durability while maintaining flexibility.

[0076] A braiding method is to bind the ends of two layers of the braided main body 100 together by fully closed or partially closed wire gathering, comprising the following steps:

[0077] S100, when weaving starts or ends, the total wire ends w involved in weaving are evenly divided into n weaving wire groups, the number of wire ends in each weaving wire group is w / n, and n can be 3, 4, 6, 8, 10, or 12;

[0078] S200, further equally divide the ε group into two bundles, where ε is a natural number greater than 0, ε≤η;

[0079] S300, the two equally divided bundles of braided yarns rotate in the same direction or in opposite directions to form a stable yarn bundle, and then the two yarn bundles are tied together in parallel to form a yarn collection group.

[0080] In one specific embodiment, the wire collection group of the braided body 100 can be fixed by welding, and the welding methods include but are not limited to: 1. welding the top ends of the inner and outer layers of the braided body 100, 2. welding the ends of the inner and outer layers of the braided body 100 at the attachment position.

[0081] In one specific embodiment, the end of the braided body 100 contains X-ray-proof precious metal hollow tubes 400, the number of which is ε. The precious metal hollow tubes 400 can be connected to the braided wires by bonding, welding or mechanical crimping.

[0082] In one specific embodiment, the end of the braided body 100 may adopt a full-wrap or partial-wrap structure design, and the w braided wires are divided into w / 2 groups, and two adjacent braided wires with inconsistent rotation directions form a wrapping group.

[0083] In one specific embodiment, the wire collection group and the rewinding group can be distributed in staggered layers.

[0084] To summarize, in the process of weaving a double-layer stent, one braiding wire is selected from each of the two layers of the braided main body 100 to form a braided wire strand, and in the process of weaving, the two braiding wires in the braided wire strand are rotated an integer multiple of 180° to form an interlayer connection point 301. The interlayer connection points 301 located at the same circumferential height of the braided main body 100 constitute an interlayer connection group, and several identical or different interlayer connection groups are distributed along the axial direction of the braided main body 100, and these interlayer connection points 301 are distributed in a non-interlayer connection structure.

[0085] Example 1

[0086] The double-layer braided body 100 mentioned in the present invention is a fully closed structure with wire ends, wherein the number of wire ends of the braided inner layer 120 and the braided outer layer 110 is the same, each interlayer connection group has 6 anisotropic connecting wire strands, and all braided wires are nickel-titanium-platinum core braided wires that can be fully developed.

[0087] Example 2

[0088] Both ends of the braided body 100 include a certain number of conical rings, and the ends of the rings contain radiopaque hollow tubes 400 that can locate the position of the stent, which contain two types of connecting wire groups, and the two types of connecting wire groups are arranged at intervals along the axial direction of the stent.

[0089] Example 3

[0090] The braided wire at one end of the braided body 100 is a closed structure formed by winding, and the radiopaque metal hollow tube 400 is sleeved on the braided wire at the winding position. The other end of the braided body 100 connects the radiopaque metal hollow tube 400 and the braided wire together by welding or mechanical crimping. The stent includes two connecting wire groups, and the interlayer connection points 301 of the two connecting wire groups are staggered along the axial direction of the stent.

[0091] The embodiments of the present application have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or improvements to the technology in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A double-layer stent, characterized in that: Includes: a braided body; The braided body comprises a braiding unit arranged along a first braiding direction and a braiding unit arranged along a second braiding direction, the braiding units in the two braiding directions are interwoven to form a hollow cylindrical structure, and the angle formed in the axial direction of the stent is in the range of 20 degrees to 180 degrees; The braiding unit is a single wire or multiple wires, which are formed into a spring, strand or rope structure by twisting, winding, etc. in advance or during the braiding process; Wherein, the braided main body comprises at least a braided outer layer and a braided inner layer, and each layer is interwoven by braiding units in two braiding directions; At least one braiding unit of the braided inner layer is cross-woven with at least one braiding unit of the braided outer layer adjacent thereto to form a connecting strand.

2. The double-layer stent according to claim 1, characterized in that: In the connecting strands, the braiding units of the braided outer layer in the braided strands and the braiding units of the braided inner layer have the same braiding direction or different braiding directions.

3. The double-layer stent according to claim 2, characterized in that: The two braiding units in the connecting wire strands are woven in a clockwise or counterclockwise direction to form an interlayer connection point.

4. The double-layer stent according to any one of claims 1 to 3, characterized in that: At the same axial position of the stent, there is at least one connecting wire strand in the circumferential direction of the stent, forming an interlayer connection point.

5. The double-layer stent according to any one of claims 1 to 3, characterized in that: At the same axial position of the braided main body, at least one interlayer connection point is provided along the circumferential direction to form an interlayer connection wire group; Two adjacent interlayer connecting wire groups are spaced apart by a preset distance along the length direction of the braided main body.

6. The double-layer stent according to claim 8, characterized in that: The interlayer connection points of different interlayer connection wire groups are distributed at the same or different circumferential positions along the axial projection of the braided main body.

7. The double-layer stent according to claim 1, characterized in that: The wire diameters of the weaving units along the first weaving direction and the weaving units along the second weaving direction are both within a range of 20 micrometers to 100 micrometers.

8. The double-layer stent according to claim 1, characterized in that: The braided unit is made of a single material or a mixture of two or more materials; the braided unit is made of a material having a shape memory effect or having X-ray opaque properties, or a material having both of the above properties.

9. The double-layer stent according to claim 8, characterized in that: The bracket is formed by weaving the braiding units of the same material and structure, or by mixing and weaving the braiding units of different materials and structures.

10. The double-layer stent according to claim 1, characterized in that: Both ends of the braided wires of the connecting wire strands are in a loose structure, a partially closed wire collection structure or a fully closed wire collection structure.

11. A weaving method, characterized in that: Using the double-layer stent according to any one of claims 1 to 2 comprises the following steps: When weaving starts or ends, the total yarn heads w of the weaving units involved in weaving are first divided into η braided wire groups, the number of wire ends in each braided wire group is w / η, and η can be 3, 4, 6, 8, 10, or 12; The ε group is further divided into two bundles, where ε is a natural number greater than 0, ε≤η; The two equally divided weaving units rotate in the same direction or in opposite directions to form a stable yarn bundle, and then the two yarn bundles are bound together in parallel to form a yarn collection group.

12. The weaving method according to claim 11, characterized in that: The end of the braided body is sleeved with a X-ray-proof noble metal hollow tube.

13. The weaving method according to claim 12, characterized in that: The end of the braided body is fully or partially wound, and the adjacent braided wires with different rotation directions form a winding group; The wire collecting group and the rewinding group can be distributed in staggered layers.

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