WO2024099161A1

WO2024099161A1 - Braided structure and medical stent

Info

Publication number: WO2024099161A1
Application number: PCT/CN2023/128115
Authority: WO
Inventors: 黄云帆; 周炯; 王晓雯
Original assignee: 神途医疗科技(上海)有限公司
Priority date: 2022-11-11
Filing date: 2023-10-31
Publication date: 2024-05-16
Also published as: CN118058884A

Abstract

Provided are a braided structure and a medical stent. The braided structure comprises a plurality of thick filaments braided together in crossing mode and a plurality of thin filaments. The thick filaments are lapped from an intersection thereof in a first direction to form first lapping nodes, and the first direction is perpendicular to an extension direction of the thick filament. A plurality of the first lapping nodes define a braided top surface along the top end of the first direction, and a plurality of the first lapping nodes define a braided bottom surface along the bottom end of the first direction. The thin filaments are intersected and lapped with the thick filaments, and the thin filaments are located in a space defined by the braided top surface and the braided bottom surface. The filaments are located in the space defined by the braided top surface and the braided bottom surface, so that the utilization rate of a space between the thick filaments of the braided structure is increased; the whole braided structure has a reduced radial thickness and can be suitable for different specifications of matching passage instruments.

Description

Braided structures and medical stents

Technical Field

The invention relates to the field of medical devices, in particular to a braided structure and a medical stent.

Background technique

As a type of medical stent, braided stents are widely used in medical fields such as neurointervention or lower limbs. The braiding process of braided stents is simpler than the cutting process, and braided stents can achieve metal coverage that cut stents cannot achieve. Therefore, they have unique advantages in the treatment of aneurysms and plaque coverage.

The dense mesh stent used in the treatment of aneurysms needs to have a certain metal coverage rate. While it has a blocking effect on the aneurysm neck, it can also improve the hemodynamics of the target vessel, reduce the impact of blood flow on the aneurysm wall, and have a certain radial support force and good wall adhesion performance. For in situ stenosis lesions, the stent mesh emphasizes the coverage of vascular wall plaques to avoid thrombus escape to the distal end and cause adverse prognosis. At the same time, in the tortuous part of the blood vessel, the stent still has good flexibility and remains attached to the wall to avoid the formation of blood flow vortices. At the same time, the strong radial support can resist a certain degree of elastic recoil of the blood vessel.

Increasing the metal coverage of the braided stent can improve some physical properties and meet corresponding clinical needs, but the problem that comes with it is that the precipitation of harmful metal ions may cause inflammatory reactions, and the area of metal materials in contact with blood increases, which can easily bring risks such as protein denaturation and platelet aggregation, increasing the probability of postoperative thrombosis.

The performance requirements for stents in aneurysms and stenosis diseases are not single. Both require the stent to have multiple mechanical properties such as a certain metal coverage, better flexibility and appropriate radial support force. Only the optimal combination of mechanical properties can achieve the best treatment effect.

In the prior art, there are braided stents that are mixed with thick and thin filaments, in which the thin filaments form a dense mesh layer to achieve the purpose of covering, and the thick filaments participate in the braiding structure to maintain the integrity of the braided structure and provide radial support. However, when thick and thin filaments are used in the braiding of the stent at the same time, whether the outer contour dimensions of the natural and compressed states meet the specifications of the matching access device is a great challenge.

Summary of the invention

The object of the present invention is to provide a braided structure and a medical stent to solve the problem that the outer contour dimensions of a medical stent mixed with thick and thin filaments in a natural state and a compressed state cannot meet the specifications of a matching access device.

In order to achieve the above object, the present invention provides a braided structure, comprising: a plurality of thick filaments and a plurality of thin filaments braided crosswise with each other;

The thick wires are overlapped at the intersection along a first direction to form a first overlap node, and the first direction is perpendicular to the extension direction of the thick wires; the top ends of the plurality of first overlap nodes along the first direction define a braided top surface, and the bottom ends of the plurality of first overlap nodes along the first direction define a braided bottom surface;

The thin filaments are intersected and overlapped with the thick filaments, and the thin filaments are located in a space defined by the woven top surface and the woven bottom surface.

Optionally, the filaments are cross-woven with each other.

Optionally, the segment of each of the thick filaments between two adjacent first overlapping nodes with opposite overlapping orders is a target segment, and the thin filament and the target segment overlap with each other to form a second overlapping node.

Optionally, the diameter of the thick wire is M, the diameter of the thin wire is N, the length of the target segment along its own extension direction is L, and among the two adjacent first overlapping nodes, the first overlapping node where the thick wire where the target segment is located is located below the thick wire intersecting with it is the target first overlapping node, and the distance between the second overlapping node and the target first overlapping node is D;

If N+M*D/L>M, the filament at the second overlapping node is located below the target segment;

If N+M*D/L≤M, the filament at the second overlapping node is located above or below the target segment.

Optionally, the thick wire between two adjacent first overlapping nodes having the same overlapping order is a fixed segment;

When the thick wire where the fixed segment is located overlaps above the thick wire intersecting with it, the thin wire at the second overlapping node is located below the fixed segment;

When the thick wire where the fixed segment is located overlaps below the thick wire intersecting with it, the thin wire at the second overlapping node is located above or below the fixed segment.

Optional, 0.002inch≤M≤0.0095inch.

Optional, 0.001inch≤N≤0.003inch.

Optionally, the target segment includes an odd number of the second overlapping nodes, all of the second overlapping nodes are evenly spaced on the target segment, and the overlapping order of each of the second overlapping nodes is the same as the overlapping order of the adjacent first overlapping nodes.

Optionally, the target segment includes an even number of the second overlapping nodes, all of the second overlapping nodes are evenly spaced on the target segment, and the overlapping order of each of the second overlapping nodes is the same as the overlapping order of the adjacent first overlapping nodes.

In order to achieve the above object, the present invention further provides a medical stent, comprising a ring-shaped main body segment, wherein the main body segment is formed by enclosing the braided structure as described above.

Optionally, the medical stent further includes an anti-coagulation coating, and the anti-coagulation coating is disposed on the periphery of the braided structure.

Optionally, the medical stent further includes auxiliary segments located on both axial sides of the main body segment.

In summary, in a braided structure and a medical stent provided by the present invention, the braided structure comprises: a plurality of thick filaments and a plurality of thin filaments braided crosswise with each other; the thick filaments overlap along a first direction at the intersection to form a first overlap node, and the first direction is perpendicular to the extension direction of the thick filaments; the top ends of the plurality of first overlap nodes along the first direction define the braided top surface, and the bottom ends of the plurality of first overlap nodes along the first direction define the braided bottom surface; the thin filaments overlap and intersect with the thick filaments, and the thin filaments are located in the space defined by the braided top surface and the braided bottom surface. Compared with the existing braided stents, it has the following advantages:

(1) The braided structure includes a plurality of thick and thin filaments that are cross-woven with each other. The thick filaments are used to enhance the radial support force of the medical stent made of the braided structure, thereby improving the opening performance of the head end of the medical stent and the overall wall adhesion performance; the dense mesh layer formed by the thin filaments is used to cover the plaque or guide the blood flow;

(2) Furthermore, the thin filaments are located in the space defined by the braided top surface and the braided bottom surface, so that the space utilization between the thick filaments is maximized, and the thin filaments occupy the space outside the thick filament compression structure to a minimum extent, so that the volume of the medical stent made of the braided structure in the natural state and the compressed state is reduced, and it can be adapted to a smaller size of the supporting access device, thereby improving the passing performance of the medical stent;

(3) Further, when the filaments are located in the space defined by the braided top surface and the braided bottom surface, During the delivery and implantation process, the thin filaments with weaker mechanical strength are not easily scratched, thus avoiding the change of the braiding form, maintaining the integrity and regularity of the stent, and avoiding the possibility of the thin filaments affecting the delivery;

(4) Furthermore, the outer surface of the braided structure is provided with an anti-coagulation coating, which can avoid direct contact between the metal braided wires and blood, reduce the release of harmful metal ions, and reduce the formation of thrombus on the surface of the medical stent made of the braided structure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1a is a schematic cross-sectional view of a braided structure provided by an embodiment of the present invention;

FIG1b is a schematic cross-sectional view of a braided structure in the prior art;

FIG2a is a schematic diagram of radial thickness of a braided structure provided by an embodiment of the present invention;

FIG2b is a schematic diagram of radial thickness of a braided structure in the prior art;

FIG3 is a schematic diagram of a braided structure provided by an embodiment of the present invention;

FIG4 is a cross-sectional view of a braided structure provided by an embodiment of the present invention;

FIG5 is a side view of a braided structure provided by an embodiment of the present invention;

FIG6a is a side view of a braided structure provided by an embodiment of the present invention;

FIG6b is a front view of a braided structure provided by an embodiment of the present invention;

FIG6c is a schematic diagram of a braided structure provided by an embodiment of the present invention;

FIG7a is a side view of another braided structure provided by an embodiment of the present invention;

FIG7b is a front view of another braided structure provided by an embodiment of the present invention;

FIG7c is a schematic diagram of another braided structure provided by an embodiment of the present invention;

FIG8 is a schematic diagram of a medical stent provided in an embodiment of the present invention.

The descriptions of the reference numerals are as follows:
1- thick filament; 2- thin filament; 3- target segment; 4- first overlapping node; 5- second overlapping node; 6- main segment; 7- auxiliary segment.

Detailed ways

In order to make the purpose, advantages and features of the present invention more clear, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that the accompanying drawings are in a very simplified form and do not The drawings are drawn to scale only for the purpose of conveniently and clearly explaining the embodiments of the present invention. In addition, the structures shown in the drawings are often part of the actual structures. In particular, the drawings need to show different focuses and sometimes use different scales.

As used in this specification, the singular forms "one", "an" and "the" include plural objects, the term "or" is generally used to include the meaning of "and/or", the term "several" is generally used to include the meaning of "at least one", and the term "at least two" is generally used to include the meaning of "two or more". In addition, the terms "first", "second" and "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second" and "third" may explicitly or implicitly include one or at least two of the features, "one end" and "the other end" and "proximal end" and "distal end" generally refer to two corresponding parts, which not only include the endpoints, wherein the "proximal end" generally represents the direction close to the doctor during the operation, and the "distal end" generally represents the direction close to the lesion during the operation. The terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral body; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. In addition, as used in this specification, an element disposed on another element generally only indicates that there is a connection, coupling, cooperation or transmission relationship between the two elements, and the connection, coupling, cooperation or transmission between the two elements may be direct or indirect through an intermediate element, and it cannot be understood as indicating or implying the spatial position relationship between the two elements, that is, one element may be in any orientation such as inside, outside, above, below or on one side of another element, unless the content clearly indicates otherwise. The terms "upper", "lower", "top" and "bottom" are generally relative position relationships arranged in the direction of gravity; the terms "vertical, vertical direction" generally refer to the direction of gravity, which is generally perpendicular to the ground, and "horizontal, horizontal plane direction" is generally in the direction parallel to the ground; for ordinary technicians in this field, the specific meanings of the above terms in this specification can be understood according to specific circumstances.

The inventors found that in the conventional braided structure schematic diagrams shown in FIG. 1b and FIG. 2b, the filaments can be The braided structure can be located above the braided top surface or below the braided bottom surface, which not only reduces the space utilization between the thick wires, but also causes the thin wires to occupy the space outside the thick wire pressing structure, resulting in an increase in the radial thickness of the braided structure, which cannot meet the use requirements of smaller-sized access devices. In the examples shown in Figures 2a and 2b, the radial thickness of the braided structure is H, while the radial thickness of the braided structure in the prior art is S, satisfying H＜S.

Based on the above research, the present invention provides a weaving structure, comprising: a plurality of thick filaments 1 and a plurality of thin filaments 2 that are cross-woven with each other; the thick filaments 1 are overlapped at the intersection along a first direction to form a first overlap node 4, and the first direction is perpendicular to the extension direction of the thick filaments 1. Specifically, in any first overlap node 4, the first direction is perpendicular to the extension direction of the two thick filaments 1 forming the first overlap node 4; the top ends of the plurality of first overlap nodes 4 along the first direction define the weaving top surface, and the bottom ends of the plurality of first overlap nodes 4 along the first direction define the weaving bottom surface; the thin filaments 2 intersect and overlap with the thick filaments 1, and the thin filaments 2 are located in the space defined by the weaving top surface and the weaving bottom surface. In some embodiments, multiple filaments 2 can be cross-woven and woven to form a mesh structure; in other embodiments, multiple filaments 2 are not cross-woven and woven, but are arranged in parallel; in other embodiments, multiple filaments 2 cross each other, but the same filament 2 is all located in the same direction of the filaments 2 that cross with it, for example, one filament 2 is located above or below all the filaments 2 that cross with it, that is, multiple filaments 2 cross but do not form a woven structure. It should be noted that in the examples shown in Figures 1a and 2a, the braided top surface is a braided surface formed by the intersection of the thick filaments 1 located at the top along the first direction, and the braided bottom surface is a braided surface formed by the intersection of the thick filaments 1 located at the bottom along the first direction. The braided top surface and the braided bottom surface can be planes, curved surfaces, or irregular surfaces with convex and concave surfaces. The first direction is the radial direction of the thick filaments 1 at the first overlapping node 4. In other embodiments, the braided top surface and the braided bottom surface may also change due to the influence of the placement position and angle. Those skilled in the art can understand that the braided top surface is the braided surface located at the top along the first direction among the braided surfaces formed by all the thick filaments 1 in the current position state; the braided bottom surface is the braided surface located at the bottom along the first direction among the braided surfaces formed by all the thick filaments 1 in the current position state; at the same time, the first direction can also be other reasonable directions. Those skilled in the art can configure the braided top surface, the braided bottom surface and the first direction according to actual conditions, and the present invention is not limited to this. In addition, it should be noted that multiple thick filaments 1 and multiple thin filaments 2 refer to the presence of multiple thick filaments 1 and thin filaments 2 heads on the cross-section of the braided structure, which can be In fact, multiple thick wires 1 and multiple thin wires 2 are woven at the same time, or there may be a back-woven structure to form multiple wire heads on the cross section. In extreme cases, the woven structure of the present invention can be formed by back-weaving one thick wire 1 and one thin wire 2.

Taking the braided stent used in blood vessels as an example, this type of stent is usually in the shape of a mesh tube, and the cross-section of the stent is usually circular. In the stent of this shape, the braided top surface and the braided bottom surface are arc surfaces; ideally, in the entire stent structure, the braided top surface and the braided bottom surface are cylindrical, the braided top surface is located on the outer surface of the stent, and the braided bottom surface is located on the inner surface of the stent, and the diameter of the cylinder formed by the braided top surface is greater than the diameter of the cylinder formed by the braided bottom surface; but due to limitations such as process, it is usually impossible to achieve a completely regular braided structure, so the braided bottom surface and the braided top surface may have irregular structures with bumps. In addition, in the mesh tube-shaped stent structure with a circular cross-section, the first direction is parallel to the radial direction of the stent. Of course, the present invention does not limit the structure in which the braided structure is located. The braided structure of the present invention can be used for mesh tube-shaped structures, and can also be used for other structures such as planar structures, spherical structures, ellipsoidal structures, and cylindrical structures.

With such configuration, the braided structure includes a plurality of interlaced thick filaments 1 and a plurality of interlaced thin filaments 2, the thick filaments 1 being used to enhance the radial support force of the medical stent made of the braided structure, improving the head end opening performance and the overall wall adhesion performance of the medical stent; the dense mesh layer formed by the thin filaments 2 can cover the plaque, reduce the probability of the plaque in the stenosis part escaping to the distal blood vessel and causing embolism, and at the same time, can also play a guiding role in the blood flow, and in the case of aneurysm disease, after being implanted into the affected diseased artery, the hemodynamics in the aneurysm is changed, thrombus is slowly formed in the aneurysm, and the intimal epithelium climbs to the surface of the medical stent, thereby repairing the diseased blood vessel and causing vascular remodeling to repair the diseased tumor-bearing artery; further, the thin filaments 2 are located in the space defined by the braided top surface and the braided bottom surface, so that the space utilization between the thick filaments 1 is maximized, and the thin filaments 2 occupy the space outside the compression wire structure of the thick filaments 1 to a minimum extent, so that the natural and compressed volumes of the medical stent made of the braided structure are reduced, and can be adapted to smaller-sized matching access devices, thereby improving the passing performance of the medical stent. At the same time, when the filament 2 is located in the space defined by the braided top surface and the braided bottom surface, the filament 2 with weaker mechanical strength is not easily scratched during the pushing and implanting process, thereby avoiding the change of the braiding shape, maintaining the integrity and regularity of the stent, and avoiding the possibility of the filament 2 affecting the pushing.

Please refer to FIG. 3 , the overlapping order of two adjacent thick wires 1 is opposite to the first overlapping order. The segment between the nodes 4 is the target segment 3, and the thin filament 2 overlaps with the target segment 3 to form a second overlap node 5; it should be noted that the target segment 3 is a segment between two first overlap nodes 4 with opposite overlap orders, but it does not mean that the overlap orders of all adjacent first overlap nodes 4 are opposite. In the embodiment shown in Figure 3, the overlap orders of all adjacent first overlap nodes are opposite; however, in some other embodiments, the overlap orders of adjacent first overlap nodes 4 may be the same. The thick filaments 1 between adjacent first overlap nodes 4 with the same overlap order are called fixed segments. When the thick filament 1 where the fixed segment is located is located above the thick filament 1 intersecting with it, the thin filament 2 can only be located below the fixed segment; when the thick filament 1 where the fixed segment is located is located below the thick filament 1 intersecting with it, the thin filament 2 can be located above or below the fixed segment. In addition, it should be noted that the overlapping order is the relative position relationship of the two overlapping wires. Taking the overlapping of thick wire 1 and thin wire 2 as an example, the overlapping order of thick wire 1 can be located below thin wire 2 or above thin wire 2, and the overlapping order between thick wire 1 and thick wire 1 can be based on the target segment 3 or the fixed segment. The thick wire 1 where the target segment 3 and the fixed segment are located can be located above the thick wire 1 intersecting with it, or below the thick wire 1 intersecting with it. In the example shown in FIG3 , thick filaments 1 and thick filaments 1, thick filaments 1 and thin filaments 2, and thin filaments 2 and thin filaments 2 are all one-press-one-weaving structures (as shown in FIGS. 4 to 5 ). The same thick filament 1 is overlapped on top of another thick filament 1 at a first overlap node 4, and then it is overlapped under another thick filament 1 at an adjacent first overlap node 4. It can be understood by those skilled in the art that in other embodiments, the weaving structure of the wire material is different, and the overlap order of two adjacent first overlap nodes 4 can also be the same. Those skilled in the art can configure the overlap order of the first overlap nodes 4 according to the weaving structure, and the present invention is not limited to this.

Furthermore, the diameter of the thick filament 1 is M, the diameter of the thin filament 2 is N, the length of the target segment 3 along its own extension direction is L, and among the two adjacent first overlapping nodes 4, the thick filament 1 where the target segment 3 is located is located below the thick filament 1 intersecting with it, and the first overlapping node 4 is the target first overlapping node, and the distance between the second overlapping node 5 and the target first overlapping node is D; if N+M*D/L＞M, then the thin filament 2 in the second overlapping node 5 is located below the target segment 3; if N+M*D/L≤M, then the thin filament 2 in the second overlapping node 5 is located above or below the target segment 3. It should be noted that, taking Figure 3 as an example, the thick filament 1 is overlapped under another thick filament 1 at the first overlapping node 4 at A, that is, the first overlapping node at A. Point 4 is the target first overlapping node. If the second overlapping node 5 satisfies N+M*D/L＞M, the thin filament 2 at this location is overlapped under the thick filament 1; if the second overlapping node 5 satisfies N+M*D/L≤M, the thin filament 2 at this location can be overlapped on the thick filament 1 or overlapped under the thick filament 1. Of course, in other embodiments, the method for determining the overlapping order can also be other reasonable methods, and those skilled in the art can configure this according to actual conditions, and the present invention is not limited to this. As an optional embodiment, 0.002inch≤M≤0.0095inch; 0.001inch≤N≤0.003inch;. In other embodiments, the wire diameters of the thick filament 1 and the thin filament 2 can also be other reasonable values, and those skilled in the art can flexibly configure the wire diameters of the thick filament 1 and the thin filament 2 according to actual conditions.

Please refer to Figures 6a to 6c. In an optional embodiment, the target segment 3 includes an odd number of second overlapping nodes 5, and all of the second overlapping nodes 5 are evenly spaced on the target segment 3. The overlapping order of the second overlapping nodes 5 located in the middle is not limited, and the overlapping order of the second overlapping nodes 5 located on both sides is the same as the overlapping order of the first overlapping nodes 4 adjacent to them (the same overlapping order is for the target segment 3, and the same overlapping order means that the thick wire 1 where the target segment 3 is located is simultaneously located above the wire intersecting with it, or, simultaneously located below the wire intersecting with it). Taking Figure 6c as an example, the thick filament 1 is overlapped on top of another thick filament 1 at A1 to form a first overlap node 4, and is overlapped on bottom of another thick filament 1 at the adjacent A2 to form a first overlap node 4. Then, at the second overlap node 5 close to the first overlap node 4 at A1, the thick filament 1 is overlapped on top of the thin filament 2, and at the second overlap node 5 close to the first overlap node 4 at A2, the thick filament 1 is overlapped under the thin filament 2. At the second overlap node 5 located in the middle, the thick filament 1 can be overlapped on top of the thin filament 2 or under the thin filament 2. In other embodiments, the overlap order of the second overlap node 5 is different due to the influence of the weaving structure, and the present invention is not limited to this.

Further, please continue to refer to Figures 6a to 6c, the target segment 3 includes n second overlapping nodes 5, wherein n1 second overlapping nodes 5 are close to the first overlapping node 4 at A1, n2 second overlapping nodes 5 are close to the first overlapping node 4 at A2, and one second overlapping node 5 is located at the middle position between the first overlapping nodes at A1 and A2, then n=n1+n2+1 is satisfied. In other embodiments, the number of second overlapping nodes 5 can also be calculated by other reasonable relationships, and the present invention is not limited to this.

Furthermore, the diameter of the thick wire 1 is M, the diameter of the thin wire 2 is N, the length of the target segment 3 along its own extension direction is L, and the target segment 3 includes an odd number of the second laps. The overlapping order of the second overlapping node 5 located in the middle is not limited, and the distance between the second overlapping node 5 and the target first overlapping node 4 (A2 in Figure 6c) is D; if M+N+M*D/L＞2M, the overlapping order of the second overlapping node 5 is that the filament 2 is located below the target segment 3; if M+N+M*D/L≤2M, the overlapping order of the second overlapping node 5 is not limited. Taking Fig. 6c as an example, the thick wire 1 is overlapped on another thick wire 1 at A1 to form the first overlap node 4, and is overlapped under another thick wire 1 at the adjacent A2 to form the first overlap node 4. The first overlap node 4 at A2 is the target first overlap node. If M+N+M*D/L＞2M is satisfied, the thick wire 1 is overlapped on the thin wire 2 at the second overlap node 5; if M+N+M*D/L≤2M is satisfied, the overlap order of the thick wire 1 at the second overlap node 5 in the target segment 3 is not limited, and it can be overlapped on the thin wire 2 or overlapped under the thin wire 2. Of course, in other embodiments, the method for determining the overlap order can also be other reasonable methods, and those skilled in the art can configure it according to actual conditions, and the present invention is not limited to this.

Please refer to Figures 7a to 7c, the target segment 3 includes an even number of the second overlap nodes 5, all of which are evenly spaced and arranged on the target segment 3, and the overlap order of the second overlap nodes 5 is the same as the overlap order of the first overlap nodes 4 adjacent thereto. Taking Figure 7c as an example, the thick wire 1 overlaps under another thick wire 1 at A3 to form the first overlap node 4, and overlaps on another thick wire 1 at the adjacent A4 to form the first overlap node 4, then at the second overlap node 5 close to the first overlap node at A3, the above-mentioned thick wire 1 overlaps under the thin wire 2, and at the second overlap node 5 close to the first overlap node 4 at A4, the above-mentioned thick wire 1 overlaps on the thin wire 2. In other embodiments, the overlap order of the second overlap node 5 is different due to the influence of the braiding structure, and the present invention is not limited to this.

Further, please continue to refer to Figures 7a to 7c, the target segment 3 includes n second overlapping nodes 5, wherein n3 second overlapping nodes 5 are close to the first overlapping node 4 at A3, and n4 second overlapping nodes 5 are close to the first overlapping node 4 at A4, and n=n3+n4 is satisfied. In other embodiments, the number of second overlapping nodes 5 can also be calculated by other reasonable relationships, and the present invention is not limited to this.

Furthermore, the diameter of the thick wire 1 is M, the diameter of the thin wire 2 is N, the length of the target segment 3 along its own extension direction is L, and the target segment 3 includes an even number of the second overlapping nodes 5, and the second overlapping nodes 5 are connected to the target first overlapping nodes (in FIG. 7c, the target first overlapping nodes are L). The distance between the first overlap node and the second overlap node 5 is D; if N+M*D/L＞M, the overlap order of the second overlap node 5 is that the thin filament 2 is located below the target segment 3; if N+M*D/L≤M, the overlap order of the second overlap node 5 is not limited. Taking Figure 7c as an example, the thick filament 1 overlaps under another thick filament 1 at A3 to form the first overlap node 4, and overlaps on another thick filament 1 at the adjacent A4 to form the first overlap node 4. The target first overlap node is at A3. If N+M*D/L＞M is satisfied, the above-mentioned thick filament 1 is overlapped under the thin filament 2 at the second overlap node 5; if N+M*D/L≤M is satisfied, the overlap order of the above-mentioned thick filament 1 at the second overlap node 5 in the above-mentioned target segment 3 is not limited, and it can be overlapped on the thin filament 2 or overlapped under the thin filament 2. Of course, in other embodiments, the method for determining the overlap order may be other reasonable methods, and those skilled in the art may configure this according to actual conditions, and the present invention is not limited to this.

Please refer to FIG8 . The present invention also provides a medical stent, including a main body segment 6 in an annular shape, and the main body segment 6 is formed by the braided structure as described above. Furthermore, the medical stent also includes auxiliary segments 7 located on both axial sides of the main body segment 6. For example, the auxiliary segment 7 can be a double-layer structure: the inner layer is woven with thin filaments 2, and the outer layer is woven with thick filaments 1; or the inner layer is woven with thick filaments 1, and the outer layer is woven with thin filaments 2; the auxiliary segment 7 is a double-layer structure, which can improve the radial support force at both ends of the stent and prevent the stent from shifting after implantation. At the same time, when the inner layer of the auxiliary segment 7 is woven with thin filaments 2 and the outer layer is woven with thick filaments 1, the exposure of the head end thin filaments 2 during the sheathing process of the stent can be prevented from affecting the sheathing, thereby reducing the difficulty of sheathing. Optionally, in other embodiments, the medical stent may be entirely formed by enclosing a braided structure; optionally, in other embodiments, part of the main segment 6 of the medical stent is formed by enclosing a braided structure as described above, and the braided structure of other parts is not limited; optionally, in other embodiments, both ends of the medical stent are formed by enclosing a braided structure as described above, and the braided structure of the middle part is not limited; those skilled in the art may configure this according to actual conditions, and the present invention is not limited to this.

As a preferred embodiment, the medical stent further includes an anti-coagulation coating, which is disposed on the periphery of the braided structure. With such a configuration, the outer surface of the braided structure is provided with an anti-coagulation coating, which can avoid direct contact between the metal braided wire and the blood, reduce the release of harmful metal ions, and reduce the formation of thrombus on the surface of the medical stent made of the braided structure, further improving the safety and practicality of the medical stent. Optionally, the anti-coagulation coating can be a natural anticoagulant coating such as a heparin coating to inhibit the formation of thrombin prokinase; the anti-coagulation coating can also be a biocompatible phosphorylcholine coating. Polymer coatings such as PC or biomimetic coatings can be used to reduce the probability of thrombosis caused by protein aggregation. Those skilled in the art can configure the anti-coagulation coating according to the specific use of the medical stent, and the present invention is not limited to this.

In summary, in the weaving structure and the medical stent provided in the embodiments of the present invention, the weaving structure includes: a plurality of thick filaments and a plurality of thin filaments that are cross-woven with each other; the thick filaments are overlapped at the intersection along a first direction to form a first overlap node, and the first direction is perpendicular to the extension direction of the thick filaments; the top ends of the plurality of first overlap nodes along the first direction define the weaving top surface, and the bottom ends of the plurality of first overlap nodes along the first direction define the weaving bottom surface; the thin filaments intersect and overlap with the thick filaments, and the thin filaments are located in the space defined by the weaving top surface and the weaving bottom surface.

With such configuration, the braided structure includes a plurality of coarse filaments braided crosswise with each other and a plurality of fine filaments braided crosswise with each other. The coarse filaments are used to enhance the radial support force of the medical stent made of the braided structure, thereby improving the opening performance of the head end of the medical stent and the overall wall adhesion performance; the dense mesh layer formed by the fine filaments is used to cover plaques or guide blood flow; further, the fine filaments are located in the space defined by the braided top surface and the braided bottom surface, so that the space utilization rate between the coarse filaments is maximized, and the fine filaments occupy the space outside the coarse filament compression structure to the minimum extent, so that the volume of the medical stent made of the braided structure in the natural state and the compressed state is reduced. It can adapt to smaller-sized supporting access devices, thereby improving the passability of the medical stent; further, when the filaments are located in the space defined by the braided top surface and the braided bottom surface, the filaments with weaker mechanical strength are not easily scratched during the pushing and implanting process, thereby avoiding changes in the braiding morphology, maintaining the integrity and regularity of the stent, and avoiding the possibility of the filaments affecting the pushing; further, the outer surface of the braided structure is provided with an anti-coagulation coating, which can avoid direct contact between the metal braided wire and the blood, reduce the release of harmful metal ions, and reduce the formation of thrombus on the surface of the medical stent made of the braided structure.

The above description is only a description of the preferred embodiments of the present invention, and is not intended to limit the scope of the present invention. Any changes or modifications made by a person skilled in the art in the field of the present invention based on the above disclosure shall fall within the scope of protection of the claims.

Claims

A braided structure, characterized in that it comprises: a plurality of thick filaments and a plurality of thin filaments that are cross-woven with each other;

The thick wires are overlapped at the intersection along a first direction to form a first overlap node, and the first direction is perpendicular to the extension direction of the thick wires; the top ends of the plurality of first overlap nodes along the first direction define a braided top surface, and the bottom ends of the plurality of first overlap nodes along the first direction define a braided bottom surface;

The thin filaments are intersected and overlapped with the thick filaments, and the thin filaments are located in a space defined by the woven top surface and the woven bottom surface.
The braided structure according to claim 1, wherein the filaments are cross-woven with each other.
The braided structure as described in claim 1 is characterized in that the segment between two adjacent first overlapping nodes of each thick wire with opposite overlapping orders is a target segment, and the thin wire and the target segment are overlapped with each other to form a second overlapping node.
The braided structure according to claim 3 is characterized in that the diameter of the thick wire is M, the diameter of the thin wire is N, the length of the target segment along its own extension direction is L, and among the two adjacent first overlapping nodes, the first overlapping node where the thick wire where the target segment is located is located below the thick wire intersecting with it is the target first overlapping node, and the distance between the second overlapping node and the target first overlapping node is D;

If N+M*D/L>M, the filament at the second overlapping node is located below the target segment;

If N+M*D/L≤M, the filament at the second overlapping node is located above or below the target segment.
The braided structure according to claim 4, characterized in that the thick wire between two adjacent first overlapping nodes having the same overlapping order is a fixed segment;

When the thick wire where the fixed segment is located overlaps above the thick wire intersecting with it, the thin wire at the second overlapping node is located below the fixed segment;

When the thick wire where the fixing segment is located overlaps below the thick wire intersecting with it, the thin wire at the second overlapping node is located above or below the fixing segment.
The braided structure according to claim 4, characterized in that 0.002 inch ≤ M ≤ 0.0095 inch.
The braided structure according to claim 4, characterized in that 0.001 inch ≤ N ≤ 0.003 inch.
The braided structure as described in claim 3 is characterized in that the target segment includes an odd number of the second overlapping nodes, all of the second overlapping nodes are evenly spaced on the target segment, and the overlapping order of each of the second overlapping nodes is the same as the overlapping order of the adjacent first overlapping nodes.
The braided structure as described in claim 3 is characterized in that the target segment includes an even number of the second overlapping nodes, all of the second overlapping nodes are evenly spaced on the target segment, and the overlapping order of each of the second overlapping nodes is the same as the overlapping order of the adjacent first overlapping nodes.
A medical stent, characterized in that it comprises a ring-shaped main body section, wherein the main body section is formed by enclosing the braided structure according to any one of claims 1 to 9.
The medical stent according to claim 10, characterized in that the medical stent further comprises an anti-coagulation coating, and the anti-coagulation coating is arranged on the periphery of the braided structure.
The medical stent according to claim 10, characterized in that the medical stent further comprises auxiliary segments located on both axial sides of the main body segment.