Braided mesh support and its manufacturing method

Abstract

This invention discloses a braided mesh stent and a method for manufacturing the braided mesh stent. The braided mesh stent comprises N sections of braided mesh tubing, which are formed by braiding filaments, where N ≥ 2 and N is a natural number. Each section of the braided mesh tubing has a first end and a second end arranged opposite to each other along its axial direction. The second end of the i-th section of the braided mesh tubing is partially connected to the first end of the (i+1)-th section of the braided mesh tubing in the circumferential direction or indirectly connected through a flexible element, forming a movement allowance between the i-th and (i+1)-th sections of the braided mesh tubing and creating a blood flow channel within the stent, where 1 ≤ i ≤ N-1 and i is a natural number. Because there is a movement allowance between adjacent braided mesh tubing sections, the two sections can move freely relative to each other, reducing the stent's obstruction of blood vessels and preventing excessive local stress that could lead to stent breakage.

Description

Technical Field

[0001] This invention belongs to the field of medical device technology, specifically relating to a braided mesh stent and its manufacturing method. The braided mesh stent can be implanted into blood vessels to maintain vascular patency. Background Technology

[0002] Atherosclerotic plaque formation, medial degeneration of arteries, and secondary thrombosis can lead to stenosis or occlusion of the lumen, causing lower limb ischemia symptoms. Lower limb arteriosclerosis obliterans is a common peripheral vascular disease. Lower limb arteriosclerosis obliterans can be classified into three categories according to the extent of lesion involvement: aortoiliac artery disease, femoropopliteal artery disease, and popliteal artery disease (i.e., below-knee artery disease). Currently, percutaneous transluminal angioplasty (PTA) is the preferred treatment for below-knee arteriosclerosis obliterans, showing good results in improving clinical symptoms, promoting ulcer and gangrene healing, and reducing amputation rates. To maintain the patency of the vessel lumen and blood flow, arterial stents are generally implanted.

[0003] Due to the small diameter of blood vessels in the lower knee region, the probability of restenosis after PTA treatment is relatively high. The implanted stent needs to ensure a certain radial support force and overcome mechanical factors such as chronic outward expansion force and low shear force. However, existing arterial stents often have the following problems:

[0004] If the stent is too long, it is easy to over-implant during the implantation process. Under normal use, it will cause excessive obstruction of bending below the knee. In severe cases, the stent may break and cause massive bleeding.

[0005] Therefore, improvements are necessary. Summary of the Invention

[0006] This invention addresses the problems of existing stents, such as excessive implantation during the implantation process due to their long length, excessive obstruction of knee flexion during normal use, and even stent breakage leading to massive bleeding in severe cases. It provides a braided mesh stent and a method for manufacturing the braided mesh stent.

[0007] The support includes N sections of braided mesh tubes, which are woven from braided wires, where N ≥ 2 and N is a natural number. Each section of the braided mesh tube has a first end and a second end that are arranged opposite to each other along its axial direction.

[0008] The second end of the i-th braided mesh tube is partially connected to the first end of the (i+1)-th braided mesh tube in the circumferential direction or indirectly connected through a flexible component, forming a movable margin between the i-th and (i+1)-th braided mesh tubes, and forming a blood flow channel within the stent, where 1≤i≤N-1 and i is a natural number.

[0009] Since the two braided mesh tubes are partially connected in the circumferential direction or connected through flexible components, a natural allowance for movement is created between the two braided mesh tubes.

[0010] In this invention, the stent is implanted into a human blood vessel, especially into a blood vessel below the knee. When the human body moves, because there is a margin of movement between two adjacent braided mesh tubes, the two braided mesh tubes can bend relatively freely, reducing the obstruction of the stent to the blood vessel. At the same time, it can effectively avoid excessive local stress on the stent, which could lead to stent breakage.

[0011] In one embodiment, the surface of the braided mesh tube has several types of diamond-shaped braided mesh holes;

[0012] The second end of the i-th section of the braided mesh tube, with its circumferential diamond-shaped braided mesh openings, is interlocked with the first end of the (i+1)-th section of the braided mesh tube, with its circumferential diamond-shaped braided mesh openings interlocking with each other.

[0013] In one embodiment, the i-th braided mesh tube and the (i+1)-th braided mesh tube are connected at only one point in the circumferential direction;

[0014] Alternatively, the i-th braided mesh tube is connected to the (i+1)-th braided mesh tube at multiple points around the circumference, with each connection point spaced apart from the others around the circumference of the braided mesh tube to create a margin of movement.

[0015] In one embodiment, the flexible element is a torsion spring.

[0016] In one embodiment, the second end of the i-th braided mesh tube is connected to the first end of the (i+1)-th braided mesh tube by a large torsion spring, the large torsion spring being coiled radially along the braided mesh tube and extending axially along the braided mesh tube.

[0017] In one embodiment, the second end of the i-th braided mesh tube is connected to the first end of the (i+1)-th braided mesh tube by a plurality of small torsion springs. Each of the small torsion springs is arranged along the circumferential direction of the bracket and spaced apart from each other. The helical diameter of the small torsion springs is smaller than the diameter of the braided mesh tube.

[0018] In one embodiment, the support frame after the N sections of braided mesh tube are connected has the following overall characteristics:

[0019] A uniformly dense section, having a first braiding density, is located in the middle section of the braided mesh support;

[0020] Two sparse segments, having a second braiding density, are located at both ends of the braided mesh support, wherein the first braiding density is greater than the second braiding density;

[0021] Two transition sections are provided, with each end of the transition section being integrally connected to one end of the dense section and one end of the sparse section, respectively. The weaving density of the transition section gradually transitions from the first weaving density of the dense section to the second weaving density of the sparse section.

[0022] In one embodiment, the dense segment has a first diameter;

[0023] The sparse segment has a second diameter, which is larger than the first diameter;

[0024] The diameter of the transition segment gradually transitions from the first diameter of the dense segment to the second diameter of the sparse segment.

[0025] In one embodiment, the surface of the braided mesh support has several types of diamond-shaped braided mesh holes;

[0026] The diamond-shaped woven mesh of the dense section has a first mesh area;

[0027] The sparse segment has a diamond-shaped woven mesh with a second mesh area, which is larger than the first mesh area.

[0028] The area of ​​the rhomboid woven mesh in the transition section gradually transitions from the area of ​​the first mesh in the dense section to the area of ​​the second mesh in the sparse section.

[0029] In one embodiment, the dense segment, the sparse segment, and the transition segment have the same number of rhomboid woven mesh openings in the circumferential direction.

[0030] The present invention also provides a method for manufacturing a braided mesh support, comprising the following steps:

[0031] S1. A cylindrical mold is provided, wherein m rows and n columns of limiting pins are embedded on the surface of the cylindrical mold, wherein m and n ≥ 2;

[0032] S2. Fix one end of the braided wire to the cylindrical mold, with it facing the first end of the cylindrical mold;

[0033] S3. The braided wire is spirally wound from the gap between two adjacent limiting pins at the first end of the cylindrical mold surface to the gap between two adjacent limiting pins at the second end, and then passes around the limiting pin at the second end of the cylindrical mold to complete the forward line.

[0034] S4. Continue to spirally wind the braided yarn from step S2 through the gap between two adjacent limiting pins and return to the first end of the cylindrical mold, then go around the limiting pin at the first end of the cylindrical mold to complete the reverse line.

[0035] S5. Repeat steps S3 and S4 several times to obtain a metal wire woven fabric with a flat mesh surface.

[0036] S6. Heat-set the metal wire braid to obtain a braided mesh tube;

[0037] S7. Weld the torsion spring between two adjacent sections of braided mesh tube to form a braided mesh tube support;

[0038] Alternatively, steps S5 to S7 can be replaced with the following steps:

[0039] A5. Repeat steps S3 and S4 several times to obtain the i-th braided mesh tube, the surface of which has several types of diamond-shaped braided mesh holes.

[0040] A6. Using braided wires, pass through one or more rhomboid braided mesh holes at the end of the i-th braided mesh tube away from the first end along the axial direction. Repeat steps S3 and S4 above to obtain the (i+1)-th braided mesh tube, where i is a natural number greater than 1.

[0041] A7. Repeat step A6 M times, where M is a natural number;

[0042] A8. Multiple braided mesh tubes are connected to form a prototype of a braided mesh tube support;

[0043] A9. The braided mesh support prototype is heat-set to obtain the braided mesh support.

[0044] In one embodiment, the specific steps for heat-setting the prototype of the braided mesh support are as follows:

[0045] The obtained braided mesh support prototype is heat-set for the first time, and after cooling, the limiting pins on the cylindrical mold are removed to obtain the intermediate product;

[0046] The intermediate product is inserted into a secondary mold, and the second heat setting and cooling are performed to obtain the braided mesh support.

[0047] The secondary mold is a cylinder that is narrow in the middle and wide at both ends. Preferably, m is a natural number from 3 to 6, and n is a natural number from 6 to 12.

[0048] The further positive and progressive effects of this invention are as follows:

[0049] 1. The braided mesh stent of the present invention has a relatively small overall length and diameter, and the second diameter of the sparse segments at both ends is larger than the first diameter of the dense segment in the middle. The sparser ends ensure that the sparse segments can be fixed within the vessel wall, while the dense segment in the middle only contacts the vessel wall, without applying significant radial pressure, thus reducing the stent's stimulation of the vessel wall. Furthermore, the denser segment in the middle, due to its tighter weave, also possesses strong radial support, maintaining vessel patency.

[0050] 2. This invention is a high-density braided mesh stent. The braiding density of the dense section is significantly higher than that of the sparse sections at both ends. It also features two transition sections with gradually changing density, diameter, and mesh area, which enhances the radial support, flexibility, and fatigue resistance of the braided mesh stent. The increased braiding density in the middle dense section promotes uniform endothelialization within the braided mesh stent, reduces chronic outward expansion forces, minimizes damage to the vascular endothelium, and thus reduces the probability of restenosis caused by inflammatory reactions in the blood vessels and the probability of stent fatigue fracture.

[0051] 3. The braided mesh stent of this invention can be connected in multiple sections and can also be equipped with torsion springs. While ensuring the radial support and fatigue resistance of the stent, it significantly enhances the flexibility of the stent, accommodating any possible torsional deformation of the braided mesh stent. Compared to existing stents, which experience radial compression, axial tension, torsion, and bending deformations during knee-to-knee bending or other bending movements, the stent of this invention causes less endothelial cell stimulation during torsional deformation, thereby reducing the incidence of inflammation caused by vascular damage. Attached Figure Description

[0052] Figure 1 This is a schematic diagram of the structure of the braided mesh tube support of the present invention when the braided mesh tube is connected by interlocking holes;

[0053] Figure 2 for Figure 1 A magnified view of a portion of the image;

[0054] Figure 3 This is a schematic diagram of the structure of the braided mesh stent of the present invention when the mesh holes are interlocked and located inside the infrakal artery.

[0055] Figure 4 This is a schematic diagram of the structure of the braided mesh tube stent of the present invention when the holes of the braided mesh tube are interlocked and located inside the artery at the knee.

[0056] Figure 5 This is a schematic diagram of the structure of the braided mesh stent of the present invention when the braided mesh is connected by a large torsion spring and is located inside the infrakal artery.

[0057] Figure 6 This is a schematic diagram of the structure of the braided mesh stent of the present invention when the braided mesh is connected by a large torsion spring and is located inside the artery at the knee.

[0058] Figure 7 A schematic diagram of the structure of the braided mesh tube of the present invention when connected by a small torsion spring;

[0059] Figure 8 for Figure 7 A magnified view of a portion of the image;

[0060] Figure 9 This is a schematic diagram of the cylindrical mold used in braiding the support frame.

[0061] Figure 10 This is a schematic diagram of the structure when the braiding wire is wound around a cylindrical mold during the braiding process.

[0062] Explanation of reference numerals in the attached diagram: 60, braided mesh tube; 50, rhomboid braided mesh opening; 40, torsion spring; 41, large torsion spring; 42, small torsion spring; 10, dense section; 20, sparse section; 30, transition section; 70, cylindrical mold; 80, blood vessel; 90, braided filament; 101, allowance for movement. Detailed Implementation

[0063] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0064] It should be noted that in this invention, "interlocking holes" means "interlocking rings", "axial" refers to the direction between two sparse segments, and "radial" refers to the direction perpendicular to the axial direction.

[0065] like Figures 1 to 6 The diagram shows the braided mesh stent of the present invention. Specifically, the braided mesh stent includes N sections of braided mesh 60, where N≥2 and N is a natural number. The braided mesh 60 is woven from braided wire 90, which is a relatively soft metal wire such as nickel-titanium alloy or platinum-iridium alloy. The diameter of the nickel-titanium alloy or platinum-iridium alloy wire ranges from 0.08 to 0.16 mm. In this invention, the length of the braided mesh 60 ranges from 15 to 50 mm, and the diameter ranges from 3 to 6 mm. This design facilitates the selection of the number of braided mesh 60 implanted during treatment based on the stenosis and occlusion length of the blood vessel 80, avoiding over-implantation due to excessive stent length, i.e., the stent extending excessively into the intact blood vessel. Simultaneously, the braided mesh stent is hand-woven and heat-set from a single metal wire on a mold. The density of the diamond-shaped braided mesh 50 on the surface of the braided mesh stent is the weaving density.

[0066] Specifically, each braided mesh tube 60 described in this section has a first end and a second end disposed opposite to each other along its axial direction. It should be noted that the shapes of each braided mesh tube 60 can be exactly the same, but they can also have some differences. Of course, the shapes of the first end and the second end of each braided mesh tube 60 can be the same or different.

[0067] The second end of the i-th braided mesh tube 60 is partially connected to the first end of the (i+1)-th braided mesh tube 60 in the circumferential direction or indirectly connected through a flexible component, forming a blood flow channel within the stent, where 1 ≤ i ≤ N-1 and i is a natural number. When the stent is implanted into the blood vessel 80, it forms a channel within the blood vessel 80 to allow blood flow, preventing thrombi or wounds on the vessel wall from blocking the blood vessel and thus affecting blood flow.

[0068] Specifically, along the axial direction of the braided mesh support, there is a movable allowance of 101 between two adjacent braided mesh sections 60.

[0069] Generally, because the human body needs to move, the stent implanted in the blood vessel will deform along with the vessel, especially when implanted in the subknee artery. The subknee artery is not only very small but also has a great deal of mobility, so the stent can easily cause obstruction. In addition, because of the great mobility of the subknee artery, the stent is easily broken due to excessive bending. Once the stent breaks, it can easily puncture the blood vessel (especially the artery), causing bleeding and potentially endangering life in severe cases.

[0070] In this embodiment, since the stent is divided into sections of braided mesh tube 60 and there is a margin of movement 101 between adjacent sections of braided mesh tube 60, when the stent bends or twists along with the human blood vessel 80, there is a space of movement between adjacent sections of braided mesh tube 60, which makes the stent less likely to break and reduces obstruction to the blood vessel 80.

[0071] In this embodiment, there is a margin of movement 101 between any two adjacent braided mesh tubes 60. This makes the movement of the support more flexible.

[0072] Specifically, each braided mesh tube 60 is woven from braided wire 90, forming a series of diamond-shaped braided mesh openings 50 after weaving. The braided wire 90 can be a relatively soft metal wire such as nickel-titanium alloy wire or platinum-iridium alloy wire. Because each braided mesh tube 60 is woven, it has good support strength. Furthermore, due to the allowance 101 between adjacent braided mesh tubes 60, it also has good flexibility.

[0073] It should be noted that the number, length and diameter of the braided mesh tube 60 in this application can be adjusted as needed. For example, the braided mesh tube 60 can have four, five or more sections, so that a very long stent can be spliced ​​together. After such a stent is implanted into the blood vessel 80 below the knee, it not only meets the requirements in terms of length, but also has very high support and flexibility.

[0074] like Figures 1 to 4As shown, in order to allow for a movable allowance 101 between two adjacent braided mesh tubes 60, the second end of the i-th section of the braided mesh tube 60 has a portion of rhomboid braided mesh holes 50 in the circumferential direction, which are interlocked with the portion of rhomboid braided mesh holes 50 in the circumferential direction at the first end of the (i+1)-th section of the braided mesh tube 60 (i.e., interlocked).

[0075] There are many ways this interlocking connection can occur: for example, it can be like... Figures 1 to 4 As shown, the i-th braided mesh tube 60 and the (i+1)-th braided mesh tube 60 are connected at only one point in the circumferential direction. Specifically, the second end of the i-th braided mesh tube 60 has two or three adjacent rhomboid braided mesh holes 50 that are interlocked with the two rhomboid braided mesh holes 50 of the (i+1)-th braided mesh tube 60, while the other rhomboid braided mesh holes 50 are separate from each other. Figures 1 to 2 The support structure is in its natural state, so when other types of diamond-shaped woven mesh are stacked together, there are no clear gaps between them as seen in the picture. Figure 3 and Figure 4 As shown, when the stent is implanted into the blood vessel 80 below the knee, the stent also bends due to the bending of the blood vessel 80, thus separating the other types of diamond-shaped braided mesh 50. Furthermore, since they are connected at only one point, the two braided mesh tubes 60 can move freely relative to each other when the stent bends, effectively preventing the stent from breaking and puncturing the blood vessel 80.

[0076] Of course, it should be emphasized that the above specific example is two diamond-shaped woven mesh holes 50 connected together, but in some embodiments, there may be one or three, or even more, as long as it does not depart from the scope of the present invention.

[0077] In some embodiments, the i-th braided mesh tube 60 is connected to the (i+1)-th braided mesh tube 60 at multiple points along the circumferential direction, with each connection point spaced apart from the others along the circumferential direction of the braided mesh tube 60 to form a movable allowance 101. For example, there may be two or three connections along the circumferential direction of the bracket, or even more, with each connection point spaced apart from the others along the circumferential direction of the bracket. When the bracket is bent, there is a movable allowance between adjacent braided mesh tubes 60, allowing for flexible relative bending and preventing the bracket from breaking.

[0078] Specifically, in order to connect the two sections of braided mesh tube 60 through the holes, the support is manufactured as follows: after manually braiding the i-th section of braided mesh tube 60 by winding a metal wire around the cylindrical mold 70, when braiding the (i+1)-th section of braided mesh tube 60, the completed i-th section of braided mesh tube 60 is slipped onto the cylindrical mold 70, and a metal wire is passed through one or more corresponding diamond-shaped braided mesh holes 50 at the port of the i-th section of braided mesh tube 60 before proceeding with the braiding process of the (i+1)-th section of braided mesh tube 60. The braided mesh tube support formed by connecting multiple sections of braided mesh tube 60 together forms a complete support as a whole.

[0079] As another example, such as Figure 5 and Figure 6 As shown, to accommodate the radial compression, axial tension, torsion, or bending deformations that occur when the braided mesh stent undergoes squatting or other bending within the infrakal artery 80, a torsion spring 40 is used as the flexible component. Specifically, the second end of the i-th section of the braided mesh 60 is connected to the first end of the (i+1)-th section of the braided mesh 60 via the torsion spring 40. Since the torsion spring 40 is generally more flexible than the braided mesh 60, when the stent is bent, the more flexible torsion spring 40 is bent, which can greatly reduce the risk of the stent breaking. Moreover, the connection via the torsion spring 40 facilitates the formation of a movement allowance 101 between the two sections of the braided mesh 60.

[0080] Specifically, such as Figure 5 and Figure 6 As shown, the torsion spring 40 can be a large torsion spring 41. It should be noted that the helical diameter of the large torsion spring 41 is basically the same as the diameter of the braided mesh tube 60. Both ends of the large torsion spring 41 are connected to a section of the braided mesh tube 60. The large torsion spring 41 is coiled radially along the braided mesh tube 60 and extends axially along the braided mesh tube 60. For example... Figure 5 and Figure 6 As shown, since the large torsion spring 41 is coiled radially along the braided mesh tube 60 and extends axially along the braided mesh tube 60, the large torsion spring 41 is less likely to break after being bent.

[0081] In another example, such as Figure 7 and Figure 8As shown, the torsion spring 40 can be several small, parallel torsion springs 42. These small torsion springs 42 form a cylindrical shape, with the helical diameter of each spring 42 being much smaller than the diameter of the braided mesh tube 60. Each of the rhomboid braided mesh openings 50 at one end of the braided mesh tube 60 is connected to a small torsion spring 42. Alternatively, each of the rhomboid braided mesh openings 50 can be connected to a small torsion spring 42 at intervals of one or more rhomboid braided mesh openings 50. The connection between the torsion spring 40 and the braided mesh tube 60 can be achieved through welding, rubber sleeves, or stainless steel sleeve pressing. The torsion spring 40 can be made of stainless steel or other alloy materials. This design maintains the radial support and fatigue resistance of the braided mesh tube stent while enhancing its flexibility and reducing the stimulation of endothelial cells during torsion, thereby reducing the incidence of inflammation caused by vascular injury.

[0082] In this application, since the stent is divided into multiple sections and there is a margin of movement 101 between each section of the braided mesh tube 60, it is very suitable for implantation into the blood vessel 80 below the knee. Especially when the stent to be implanted is very long, the stent of this application can not only ensure the length of the stent, but also take into account support and flexibility.

[0083] In addition, such as Figure 1 , Figure 3 , Figure 5 and Figure 7 As shown, the braided mesh support formed by connecting multiple braided mesh tubes 60 generally consists of a dense section 10, two sparse sections 20, and two transition sections 30.

[0084] As an example, the dense section 10 of the braided mesh support of the present invention is a hollow small cylinder, while the sparse sections 20 at both ends are hollow large cylinders.

[0085] On the one hand, such as Figure 1 As shown, the diameter of the cylindrical dense segment 10 is smaller than the diameter of the sparse segment 20. Specifically, the dense segment 10 has a first diameter of approximately 3-5 mm, while the sparse segment 20 has a second diameter of approximately 4-6 mm. Because the first diameter of the dense segment 10 is smaller than the second diameter of the sparse segment 20, when the sparse segment 20 with its larger second diameter supports the arterial vessel 80, the dense segment 10 with its smaller first diameter does not exert strong radial pressure on the arterial vessel wall, thus causing less interference with knee flexion and less irritation to the vessel wall. Furthermore, the sparse segments 20 at both ends supporting the arterial vessel wall also prevent displacement of the braided stent. On the other hand, the cylindrical dense segment 10 is longer than the sparse segments 20 at both ends. Specifically, the dense segment 10 has a first length of approximately 10-30 mm, while the sparse segment 20 has a second length of approximately 3-10 mm.

[0086] The surfaces of the dense cylindrical segment 10 in the middle and the sparse segments 20 at both ends each have a number of through-holes resembling diamond-shaped woven meshes 50. The distribution of the number of these meshes 50 per unit area differs between the dense and sparse segments 20. The number of these meshes 50 per unit area on the surface of the dense cylindrical segment 10 represents a first weave density, approximately 25-60 PPI. The number of these meshes 50 per unit area on the surface of the sparse segments 20 represents a second weave density, approximately 10-20 PPI. The dense segment 10, with its higher initial braiding density, enhances the radial support (which maintains the stent's shape and prevents thrombi on the vessel wall from deforming it), flexibility, and fatigue resistance of the braided stent. The increased braiding density in the middle dense segment 10 promotes uniform endothelialization within the braided stent, reduces chronic outward expansion forces, and minimizes damage to the vessel wall, thereby lowering the probability of restenosis caused by inflammation and stent fatigue fracture. Furthermore, the rhomboid braided mesh 50 of the dense segment 10 has a smaller mesh area than the sparse segment 20; that is, the rhomboid braided mesh 50 of the dense segment 10 has a first mesh area of ​​2-4 mm². 2 The sparse segment 20 has a second mesh area of ​​4-6 mm. 2 Because the first mesh area of ​​the dense section 10 is small, the weaving density per unit area can be further increased.

[0087] As an example, the braided mesh support of the present invention has two transition sections 30, which are hollow frustum-shaped and have a third length of 4-8 mm. As the name suggests, the transition sections 30 mainly serve as a transition connection. The two ends of the transition sections 30 are integrally connected to one end of the dense section 10 and one end of the sparse section 20, respectively. The function of the transition sections 30 is to better connect the dense section 10 and the sparse end 20, thereby improving the radial support force and fatigue resistance of the braided mesh support. It should be noted that the braiding density of the transition sections 30 gradually transitions from the first braiding density of the dense section 10 to the second braiding density of the sparse section 20, the diameter gradually transitions from the first diameter of the dense section 10 to the second diameter of the sparse section 20, and the mesh area gradually transitions from the first mesh area of ​​the dense section 10 to the second mesh area of ​​the sparse section 20. The first braiding density is greater than the second braiding density. This increases the braiding density of the intermediate dense section 10, which is beneficial for the uniformization of the braided mesh support and reduces the chronic outward expansion force of the braided mesh support. The first diameter is smaller than the second diameter, and the area of ​​the first mesh is smaller than the area of ​​the second mesh, thus forming a braided mesh support with a higher weaving density in the middle than at both ends, and a first diameter in the middle smaller than the second diameters at both ends. It should be noted that in some embodiments, the number of rhomboid braided mesh openings 50 in the circumferential direction is consistent across the dense section 10, the sparse section 20, and the transition section 30; preferably, the number of rhomboid braided mesh openings 50 is 6-12.

[0088] In this embodiment, as Figure 5 As shown, the support is divided into two sections. Along the axis of the support, the diameter of each braided mesh tube 60 is smaller and the braiding density is higher at the end facing the center of the support, while the diameter is larger and the braiding density is lower at the end away from the center of the support. Of course, in some embodiments, the braided mesh tube 60 can also have three or more sections. When the braided mesh tube 60 has three sections, the middle section can have the same diameter, while the two braided mesh tube sections 60 at both ends can adopt the structure described above for only two sections.

[0089] In addition, it should be emphasized that in some embodiments, the diameter and density of the braided mesh support can be basically the same at different locations.

[0090] In another embodiment, a heat-sealed membrane can be added to the outer or inner surface of the braided mesh stent. The membrane material can be polytetrafluoroethylene or polyurethane, thus obtaining a covered stent. The braided mesh stent with added membrane not only provides the support of a bare stent but also helps prevent inflammation and thrombosis and restore normal blood flow through the mechanical barrier effect of the membrane and the special substances on the membrane surface. Arterial repair using this braided mesh stent has advantages such as minimal trauma and rapid recovery.

[0091] like Figures 5 to 8As shown, the braided mesh support includes a dense section 10 located at the middle end of the support, two sparse sections 20 located at both ends of the support, two transition sections 30 connecting the dense section 10 and the two sparse sections 20, and a torsion spring 40 located in the middle section of the support. The surface of the braided mesh 60 also has several types of diamond-shaped braided mesh holes 50.

[0092] As an example, since stents that are too long or have a large diameter are prone to breakage, the braided mesh stent of this invention is hand-woven, with the appropriate length woven according to the actual situation, thereby improving the stent's flexibility and applicability. The braiding wire 90 is made of relatively soft metal wires such as nickel-titanium alloy or platinum-iridium alloy, with a diameter range of 0.08-0.16 mm. The overall length and diameter of the stent of this invention are relatively small, with a length range of 15-50 mm and a diameter range of 3-6 mm. This design facilitates the selection of the number of stents to be implanted during treatment based on the length of stenosis and blockage in the blood vessel 80, avoiding over-implantation of stents in areas without dissection or stenosis due to the inability to adjust the stent length. Simultaneously, the braided mesh stent is hand-woven and heat-set from a single metal wire on a mold, and the density of the diamond-shaped braided mesh 50 on the surface of the braided mesh stent is the braiding density.

[0093] The method for weaving the braided mesh support of the present invention includes the following steps:

[0094] S1. Provide a cylindrical mold 70 (e.g.) Figure 9 and Figure 10 As shown, a cylindrical mold 70 is used as a weaving mold. Three to six rows of locating pins are arranged on its surface, with six to twelve pins per row. The planes of each row of locating pins are parallel to each other, and the number of locating pins at the waist and both ends is the same. The spacing between the rows of locating pins on the cylindrical mold 70 is adjusted to obtain different PPI (weaving density or mesh density). The locating pins are evenly fixed and connected on the mold surface, allowing the braided wires to be evenly wrapped around the mold.

[0095] S2. Fix one end of the braided wire 90 to the cylindrical mold 70, and face the first end of the cylindrical mold 70;

[0096] S3. The braided yarn 90 is spirally wound from the gap between two adjacent limiting pins at the first end of the cylindrical mold 70 to the gap between two adjacent limiting pins at the second end, and then passes around the limiting pin at the second end of the cylindrical mold 70 to complete the forward line (the forward line is from top to bottom).

[0097] S4. Continue to spirally wind the braided wire 90 from step S2 through the gap between two adjacent limiting pins and return to the first end of the cylindrical mold 70. Then, it goes around the limiting pin at the first end of the cylindrical mold 70 to complete the reverse line (the reverse line is from bottom to top). When the reverse line is laid, the number of grids that the limiting pins are staggered is the same as the number of grids that are staggered in the forward line, forming a rhomboid mesh that is parallel in the same direction and crosses in the opposite direction. This rhomboid mesh is a rhomboid braided mesh 50.

[0098] S5. Repeat steps S3 and S4 several times, and when the braided wire is spirally wound at 90 degrees to form a forward or reverse line, thread the wire at the intersection point. Each threading is separated by one intersection point. Repeat this process to form a mutually restrictive rhomboid mesh. The metal wires are woven inward and outward at the remaining intersection points until the overall weaving density reaches the set density. Finally, the reverse line returns to the initial point to obtain a metal wire woven fabric with a flat mesh surface.

[0099] S6. Heat-set the metal wire braid to obtain the braided mesh tube 60. During the heat-setting process, the metal braid can be heat-set for the first time, and after cooling, the limiting pins on the cylindrical mold 70 can be removed to obtain an intermediate product. Then, the intermediate product is inserted into the secondary mold, and the second heat-setting and cooling process yields the braided mesh tube 60. The shape of the secondary mold can be adjusted as needed. For example, a cylinder with a uniform diameter can be used, or a cylinder that is narrow at one end and wide at the other can be used.

[0100] S7. Weld the torsion spring 40 between two adjacent braided mesh tubes 60 to form a braided mesh tube support.

[0101] In another embodiment, the steps between S5 and S7 can be replaced by the following steps:

[0102] A5. Repeat steps S3 and S4 several times to obtain the i-th braided mesh tube 60, the surface of which has several types of diamond-shaped braided mesh holes 50.

[0103] A6. A braided wire 90 is passed through a rhomboid braided mesh hole 50 at a predetermined end along the axial direction of the i-th section of the braided mesh tube 60. This predetermined end is the end of the i-th section of the braided mesh tube 60 furthest from the first end of the cylindrical mold 70. Steps S3 and S4 are repeated to obtain the (i+1)-th section of the braided mesh tube 60, where i is a natural number greater than 1.

[0104] A7. Repeat step A6 M times, where M is a natural number;

[0105] A8. Multiple braided mesh tubes 60 are connected to form a prototype of a braided mesh tube support;

[0106] A9. The braided mesh support prototype is heat-set to obtain the braided mesh support.

[0107] After the brackets in the above two embodiments have been heat-set and cooled, the joints are connected by welding, rubber sleeves or stainless steel sleeves, etc., to obtain a complete braided mesh tube bracket.

[0108] In this embodiment, i equals 1, so the support contains two sections of braided mesh tube 60. Of course, in some embodiments, i can be equal to 2, 3, or 4 or even more.

[0109] Since the (i+1)th braided mesh tube 60 is braided by passing the braided wire 90 through the rhomboid braided mesh holes 50 of the i-th braided mesh tube 60, the i-th braided mesh tube 60 and the (i+1)th braided mesh tube 60 can be connected by interlocking holes.

[0110] In addition, the specific steps for heat setting the prototype of the braided mesh support are as follows:

[0111] The obtained braided mesh support prototype is heat-set for the first time, and after cooling, the limiting pins on the cylindrical mold 70 are removed to obtain an intermediate product; the intermediate product is inserted into a secondary mold, and heat-set and cooled for the second time to obtain the braided mesh support; wherein, the secondary mold is a cylinder that is narrow in the middle and wide at both ends.

[0112] Since the secondary mold is a cylinder that is narrow in the middle and wide at both ends, after the bracket is heat-set twice, it forms a bracket with a small diameter in the middle and a large diameter at both ends.

[0113] Additionally, it should be noted that because the braiding is denser in the middle of the support, the number of braided wires staggered from the limiting pins can be smaller when threading the reverse and forward lines. However, when the density is sparser at both ends of the support, the number of braided wires staggered from the limiting pins can be larger.

[0114] In addition, at the same location, the number of staggered grids of the limiting pins is the same as the number of staggered grids when moving in the same direction, forming a rhomboid grid that is parallel in the same direction and intersects in opposite directions.

[0115] In a further preferred embodiment, when the braided yarn is spirally wound at 90 degrees to form a forward or reverse line, the yarn is threaded at the intersection point, with each threading occurring at a distance from one intersection point, and this process is repeated to form a mutually constraining rhomboid grid.

[0116] In this embodiment, m is a natural number from 3 to 6, and n is a natural number from 6 to 12. Of course, in some embodiments, the number can be increased or decreased accordingly.

[0117] The stent, with its aforementioned structure, ensures the connection of multiple braided mesh tubes 60 while allowing sufficient space for torsional deformation, thus increasing the axial tensile strength of the stent. This satisfies the tensile deformation requirements of the infrakal artery while reducing damage to endothelial cells. After the entire braided mesh stent is woven and passed through a secondary shaping mold, multiple annular braided mesh holes appear at the connection points of the multiple braided mesh tubes 60, forming multiple closed support units on the stent. This further enhances the radial support force of the stent, withstands the compressive deformation of the infrakal artery, effectively supports the vessel 80 to provide blood flow while providing axial rotation space, facilitating infrakal movement, improving fatigue resistance, and preventing repeated torsional fractures of the stent.

[0118] The present invention has been described in detail above with reference to the accompanying drawings and embodiments. Those skilled in the art can make various modifications to the present invention based on the above description. Therefore, certain details in the embodiments should not be construed as limiting the present invention. The present invention shall be protected by the scope defined in the appended claims.

Claims

1. A braided mesh tube support, characterized in that, The support includes N sections of braided mesh tubes, which are woven from braided wires, where N ≥ 2 and N is a natural number. Each section of the braided mesh tube has a first end and a second end that are arranged opposite to each other along its axial direction. Wherein, the second end of the i-th braided mesh tube is partially connected to the first end of the (i+1)-th braided mesh tube in the circumferential direction, forming a movable margin between the i-th braided mesh tube and the (i+1)-th braided mesh tube, and forming a blood flow channel within the stent, 1≤i≤N-1 and i is a natural number; The surface of the braided mesh tube has several types of diamond-shaped braided mesh holes; The rhomboid braided mesh at the second end of the i-th section of the braided mesh tube in the circumferential direction is interlocked with the rhomboid braided mesh at the first end of the (i+1)-th section of the braided mesh tube in the circumferential direction. The i-th braided mesh tube and the (i+1)-th braided mesh tube are interlocked with each other at multiple points in the circumferential direction, with each connection point being spaced apart from the others in the circumferential direction of the braided mesh tube to form a margin of movement.

2. The braided mesh support as described in claim 1, characterized in that, The bracket, after being connected by N sections of braided mesh tubing, has the following overall characteristics: A uniformly dense section, having a first braiding density, is located in the middle section of the braided mesh support; Two sparse segments, having a second braiding density, are located at both ends of the braided mesh support, wherein the first braiding density is greater than the second braiding density; Two transition sections are provided, with each end of the transition section being integrally connected to one end of the dense section and one end of the sparse section, respectively. The weaving density of the transition section gradually transitions from the first weaving density of the dense section to the second weaving density of the sparse section.

3. The braided mesh support as described in claim 2, characterized in that, The dense segment has a first diameter; The sparse segment has a second diameter, which is larger than the first diameter; The diameter of the transition segment gradually transitions from the first diameter of the dense segment to the second diameter of the sparse segment.

4. The braided mesh support as described in claim 2, characterized in that, The surface of the braided mesh support has several types of diamond-shaped braided mesh holes. The diamond-shaped woven mesh of the dense section has a first mesh area; The sparse segment has a diamond-shaped woven mesh with a second mesh area, which is larger than the first mesh area. The area of ​​the rhomboid woven mesh in the transition section gradually transitions from the area of ​​the first mesh in the dense section to the area of ​​the second mesh in the sparse section.

5. The braided mesh support as described in claim 3, characterized in that, The dense section, the sparse section, and the transition section all have the same number of rhomboid woven mesh openings in the circumferential direction.

6. A method for manufacturing a braided mesh support according to any one of claims 1 to 5, characterized in that... Includes the following steps: S1. A cylindrical mold is provided, wherein m rows and n columns of limiting pins are embedded on the surface of the cylindrical mold, wherein m and n ≥ 2; S2. Fix one end of the braiding wire to the cylindrical mold, with the fixing position facing the first end of the cylindrical mold; S3. The braided wire is spirally wound from the surface of the cylindrical mold toward the gap between the two adjacent limiting pins at the first end to the gap between the two adjacent limiting pins at the second end, and then passes around the limiting pin at the second end of the cylindrical mold to complete the forward line; S4. Continue to spirally wind the braided yarn from step S2 through the gap between two adjacent limiting pins and return to the first end of the cylindrical mold, then go around the limiting pin at the first end of the cylindrical mold to complete the reverse line. A5. Repeat steps S3 and S4 several times to obtain the i-th braided mesh tube, the surface of which has several types of diamond-shaped braided mesh holes. A6. Using braided wire, pass through a diamond-shaped braided mesh hole at the end of the i-th braided mesh tube away from the first end along the axial direction. Repeat steps S3 and S4 above to obtain the (i+1)-th braided mesh tube, where i is a natural number greater than 1. A7. Repeat step A6 M times, where M is a natural number; A8. Multiple braided mesh tubes are connected to form a prototype of a braided mesh tube support; A9. The braided mesh support prototype is heat-set to obtain the braided mesh support.

7. The method as described in claim 6, characterized in that, The specific steps for heat setting the prototype of the braided mesh support are as follows: The obtained braided mesh support prototype is heat-set for the first time, and after cooling, the limiting pins on the cylindrical mold are removed to obtain the intermediate product; The intermediate product is inserted into a secondary mold, and the second heat setting and cooling are performed to obtain the braided mesh support. The secondary mold is a cylinder that is narrow in the middle and wide at both ends.

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