Knitted covered stent

Abstract

The present application relates to a knitted covered stent, comprising: a support layer and a flow-restricting layer, wherein the support layer is formed from braiding units braided into a hollow cylindrical braided structure, and the flow-restricting layer is formed from braiding units knitted together; the support layer serves as a base scaffold of the stent and provides necessary mechanical support, the flow-restricting layer is a knitted structure covering an exterior of the support layer, wherein the flow-restricting layer uses a knitting process where the braiding units are interlooped and continuously knitted into a mesh covering the exterior of the support layer, and an inner side of the flow-restricting layer is adhered to an outer side of the support layer, resulting in a knitted covered stent comprising a braided structure + a knitted structure; moreover, an interlayer connection structure is provided between the support layer and the flow-restricting layer, so as to achieve interlayer connection and fixation between the support layer and the flow-restricting layer. Compared with conventional laser-cut scaffold + polymer membrane designs, the present application exhibits superior wall apposition and compliance, with better adaptability to vessel morphology and dynamics, thereby improving implantation performance and therapeutic efficacy of stents.

Description

Knitted film-coated support Technical Field

[0001] This application relates to the field of medical device technology, and in particular to a knitted covered stent. Background Technology

[0002] Minimally invasive interventional surgery is a common treatment for intracranial aneurysms. Currently, commonly used techniques for treating intracranial aneurysms include coil embolization, stent-assisted coil embolization, flow diverter placement, and covered stent implantation. For large and giant saccular aneurysms, wide-necked aneurysms, fusiform aneurysms, and dissecting aneurysms, the use of traditional coil or stent-assisted coil embolization techniques can lead to prolonged intraoperative time, incomplete aneurysm occlusion, and a high postoperative complication rate. Flow diverters, due to their high weave density, may also have issues with incomplete apposition to the aneurysm wall and flexibility, which can affect the postoperative aneurysm occlusion rate and the occurrence of ischemic complications. Summary of the Invention

[0003] In view of this, this application proposes a knitted film-coated scaffold.

[0004] According to one aspect of this application, a knitted coated scaffold is provided, comprising: a support layer and a flow-blocking layer.

[0005] The support layer is woven from braided units, forming a hollow columnar braided structure.

[0006] The flow-blocking layer is a knitted structure that is formed by knitting units looping together and continuously knitting into a net, covering the outside of the support layer. The inner side of the flow-blocking layer is attached to the outer side of the support layer, and there is an interlayer connection structure between the support layer and the flow-blocking layer to achieve interlayer connection and fixation between the support layer and the flow-blocking layer.

[0007] In one possible implementation, at least one metal braided unit of the support layer extends out of the braided structure of the flow-blocking layer along the knitted mesh, and then inserts into the braided structure of the flow-blocking layer along the knitted mesh, forming an interlayer connection structure between the support layer and the flow-blocking layer.

[0008] In one possible implementation, the support layer and the flow-blocking layer are connected by metal rings, which connect the braided units of the adjacent support layer and the braided units of the flow-blocking layer to form an interlayer connection structure between the support layer and the flow-blocking layer.

[0009] In one possible implementation, there is an interlayer connection structure between the support layer and the flow-blocking layer;

[0010] The interlayer connection structure comprises multiple structures, which are evenly distributed along the circumference and axial direction of the knitted film-coated bracket.

[0011] In one possible implementation, the support layer comprises braided units arranged along a first braiding direction and braided units arranged along a second braiding direction, the braided units in the two braiding directions interweaving to form a hollow columnar structure.

[0012] In one possible implementation, the flow-blocking layer is woven using warp knitting or weft knitting techniques.

[0013] In one possible implementation, the length of the support layer in the axial direction of the support is greater than the length of the flow-blocking layer in the axial direction of the support.

[0014] In one possible implementation, the outer diameter of the support layer is smaller than the outer diameter of the flow-blocking layer.

[0015] In one possible implementation, the number of yarn ends in the braided unit of the support layer is 2m, where 4≤m≤48;

[0016] The number of yarn ends in the braided unit of the flow-blocking layer is n, where n≥1.

[0017] In one possible implementation, the interlayer connection structure is arranged at a frequency of a in the circumferential direction of the support, where 1≤a≤2m;

[0018] The interlayer connection structure is laid out at a frequency of b along the axial direction of the support, where b = x * p, p is the weaving layer pitch, and x > 0.

[0019] In one possible implementation, the metal coverage of the knitted film-coated scaffold support layer is in the range of 10% to 40%.

[0020] The grid size of the flow-blocking layer is in the range of 20 micrometers to 200 micrometers.

[0021] In one possible implementation, a metal ring is provided between the braided unit of the support layer and the braided unit of the flow-blocking layer;

[0022] The metal ring is a hollow tubular structure or a C-shaped tubular structure, and the braided units of the support layer and the flow-blocking layer are fixed together at the interlayer connection structure.

[0023] In one possible implementation, the cross-section of the braided unit includes, but is not limited to, irregularly shaped structures such as circles, triangles, and hollow rings.

[0024] In one possible implementation, the braiding unit is a material with shape memory properties such as nickel-titanium or cobalt-chromium, or a DFT material containing radiopaque components, or a shape memory material such as nickel-titanium or cobalt-chromium prepared alone or in combination with radiopaque materials such as platinum-tungsten or platinum-iridium.

[0025] In one possible implementation, the outer diameter of the covered stent is in the range of 1.5 to 12 mm, and the length is in the range of 10 to 80 mm.

[0026] In one possible implementation, at the start or end of weaving, the total number of yarn ends w involved in weaving is first divided into ƞ weaving yarn groups, and the number of yarn ends in each weaving yarn group is w / ƞ, where ƞ can be 3, 4, 6, 8, 10, or 12.

[0027] The ɛ group is further divided into two bundles, where ɛ is a natural number greater than 0 and ɛ≤ƞ; the two bundles are rotated in the same or opposite directions to form a stable filament bundle, and the two filament bundles are bound together in parallel to form a closed take-up group.

[0028] In one possible implementation, the ends of the support layer are partially closed, fully closed, or loose.

[0029] The ends of the support layer can be partially or fully enclosed by means of winding, bundling, welding or bonding.

[0030] In one possible implementation, the braiding units of the support layer and the flow-blocking layer are of one filament diameter or a mixture of multiple filament diameters.

[0031] The yarn diameter of the braiding unit is in the range of 0.0005 inches to 0.005 inches;

[0032] The diameter of the braided unit of the support layer is greater than or equal to the diameter of the braided unit of the flow-blocking layer.

[0033] A method for preparing a knitted coated scaffold, comprising the following steps:

[0034] The support layer is obtained by weaving the aforementioned braiding unit using a braiding process;

[0035] Along the outer surface of the support layer, the flow-blocking layer is woven using a knitting process, and during the knitting process, the knitting units are regularly interwoven into the support layer to obtain the flow-blocking layer and form a knitted film-coated support with interlayer connections.

[0036] The knitted coated bracket is heat-treated for shaping.

[0037] The beneficial effects of the knitted coated stent of this application embodiment are as follows: The knitted coated stent uses a support layer as the core carrier and a flow-blocking layer as the coating layer. The knitting units of the support layer are interwoven inside and outside the flow-blocking layer to form an interlayer connection structure. Alternatively, hollow tubular or C-shaped tubular metal rings can be used to connect the knitting units of the support layer and the flow-blocking layer to form an interlayer connection structure, thereby achieving interlayer connection and fixation between the support layer 120 and the flow-blocking layer 110. Alternatively, welding, dipping, or gluing can be used directly to form an interlayer connection structure, achieving a tight and firm connection between the support layer and the flow-blocking layer at certain locations. This can prevent interlayer separation problems that may occur during the use of the stent, thereby ensuring the long-term stability and reliability of the stent. In particular, compared with traditional coated stents, the flow-blocking layer, which is the coating layer in this invention, is not merely a thin film without mechanical properties. Both the flow-blocking layer and the support layer are carefully made using knitting units with shape memory effect. In addition, the support layer is braided and the flow-blocking layer is knitted, resulting in a braided structure + knitted structure covered stent. Compared with the traditional cut skeleton + polymer membrane design, it exhibits superior wall adhesion and compliance, and can better adapt to the shape and changes of blood vessels, thereby improving the stent implantation effect and treatment effect.

[0038] Other features and aspects of this application will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0039] The accompanying drawings, which are included in and form part of this specification, illustrate exemplary embodiments, features, and aspects of this application together with the specification and serve to explain the principles of this application.

[0040] Figure 1 shows a schematic diagram of the main structure of the knitted film-coated bracket according to an embodiment of this application;

[0041] Figure 2 shows a schematic diagram of the interlayer connection structure of the knitted film-coated scaffold according to an embodiment of this application;

[0042] Figure 3 shows another schematic diagram of the interlayer connection structure of the knitted film-coated scaffold according to an embodiment of this application;

[0043] Figure 4 shows a schematic diagram of the interlayer connection structure of the support layer of the knitted coated scaffold according to an embodiment of this application, which has a special structure.

[0044] Figure 5 shows a schematic diagram of the weft-knitted structure of the flow-blocking layer of the knitted coated support according to an embodiment of this application;

[0045] Figure 6 shows a schematic diagram of the warp-knitted structure of the knitted coated support flow barrier layer according to an embodiment of this application;

[0046] Figure 7 shows a schematic diagram of the cross-sectional structure of the metal ring connecting the support layer and the flow-blocking layer to form an interlayer connection structure according to an embodiment of this application.

[0047] Figure 8 shows a schematic diagram of the overall effect of the bracket in an embodiment of this application, where the metal ring connecting the support layer and the flow-blocking layer form an interlayer connection structure.

[0048] Figure 9 shows a schematic diagram of the closed take-up group structure of the knitted film-coated bracket according to an embodiment of this application;

[0049] Figure 10 shows a schematic diagram of the fixing method of the closed take-up group structure of the knitted film-coated bracket according to an embodiment of this application;

[0050] Figure 11 shows a schematic diagram of the structure of the support layer end portion of the bundle termination according to an embodiment of this application;

[0051] Figure 12 shows a schematic diagram of the structure of the support layer end wrapping back according to an embodiment of this application;

[0052] Figure 13 shows a schematic diagram of the structure of the support layer end portion bundle termination and end wrapping staggered layer arrangement in an embodiment of this application;

[0053] Figure 14 shows a schematic diagram of the structure for fixing the loose wire ends of the flow-blocking layer according to an embodiment of this application; Detailed Implementation

[0054] Various exemplary embodiments, features, and aspects of this application will now be described in detail with reference to the accompanying drawings. The same reference numerals in the drawings denote elements that have the same or similar functions. Although various aspects of the embodiments are shown in the drawings, they are not necessarily drawn to scale unless specifically indicated otherwise.

[0055] It should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the present invention or simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0056] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0057] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments.

[0058] Furthermore, to better illustrate this application, numerous specific details are provided in the following detailed embodiments. Those skilled in the art should understand that this application can be implemented without certain specific details. In some instances, methods, means, components, and circuits well-known to those skilled in the art have not been described in detail in order to highlight the main points of this application.

[0059] As shown in Figure 1, the knitted coated support 10 of this embodiment includes a support layer 120 and a flow-blocking layer 110. The support layer 120 is woven from knitting units and has a hollow columnar knitted structure. The flow-blocking layer 110 is also knitted from knitting units. The support layer 120 serves as the basic skeleton of the support 10, providing necessary mechanical support. The flow-blocking layer 110 is a knitted structure covering the outside of the support layer 120. The flow-blocking layer 110 uses a finer knitting process to knit the knitting units into a knitted structure covering the outside of the support layer 120. The inner side of the flow-blocking layer 110 is attached to the outer side of the support layer 120, and there is an interlayer connection structure between the support layer and the flow-blocking layer. The knitting units of the support layer 120 are interwoven inside and outside the flow-blocking layer 110 to form an interlayer connection structure, thereby achieving interlayer connection and fixation between the support layer 120 and the flow-blocking layer 110.

[0060] In this embodiment, the knitted coated stent 10 of the present invention uses a support layer 120 as the core carrier and a flow-blocking layer 110 as the coating layer. The knitted units of the support layer 120 are interwoven inside and outside the flow-blocking layer 110 to form an interlayer connection structure. Alternatively, hollow tubular or C-shaped tubular metal rings can be used to connect the knitted units of the support layer and the flow-blocking layer to form an interlayer connection structure, thereby achieving interlayer connection and fixation between the support layer 120 and the flow-blocking layer 110. Alternatively, welding, dipping, or gluing can be used to achieve a tight and firm connection between the support layer 120 and the flow-blocking layer 110 at certain locations. This can prevent interlayer separation problems that may occur during the use of the stent 10, thereby ensuring the long-term stability and reliability of the stent 10. In addition, compared with the traditional coated stent 10, the flow-blocking layer 110, which is the coating layer in the present invention, is not just a thin film without mechanical properties. Both the flow-blocking layer 110 and the support layer 120 are carefully made using knitted units with shape memory effect. In addition, the support layer 120 is braided and the flow-blocking layer 110 is knitted, resulting in a braided structure + knitted structure knitted covered stent 10. Compared with the traditional cut skeleton + polymer membrane design, it exhibits superior wall adhesion and compliance, and can better adapt to the shape and changes of blood vessels, thereby improving the implantation effect and treatment effect of stent 10.

[0061] Furthermore, the application of knitted structures as a coating layer offers greater flexibility and adaptability compared to traditional polymer membranes. By cleverly combining knitted loops of different sizes, especially by designing large knitted loops at the branch vessel coverage, the problem of branch vessel occlusion can be effectively avoided.

[0062] In one specific embodiment, at least one braided unit of the support layer 120 extends out of the braided structure of the flow-blocking layer 110 along the knitted mesh, and then inserts into the braided structure of the flow-blocking layer 110 along the knitted mesh, forming an interlayer connection structure between the support layer 120 and the flow-blocking layer 110. By interlacing the braided units of the support layer 120 within and outside the flow-blocking layer 110 at local locations of the support 10, the deformation resistance of the interlayer connection structure 200 is increased. After external force is applied, the interlayer connection structure 200 avoids the risk of interlayer separation due to the difference in deformation recovery ability between the flow-blocking layer 110 and the support layer 120 after the external force is released, because the flow-blocking layer 110 and the support layer 120 are nested together. Even if the flow-blocking layer 110 and the support layer 120 are displaced when external force is applied, the flow-blocking layer 110 can quickly return to its original position under the action of the relatively rigid support layer 120, further resisting the risk of local delamination of the support 10. The interlayer connection structures 200 distributed throughout the support 10 further increase the overall resistance of the support 10 to delamination.

[0063] Furthermore, in this specific embodiment, there is an interlayer connection structure 200 between the support layer 120 and the flow-blocking layer 110. Multiple interlayer connection structures 200 are evenly distributed along the circumference and axial direction of the coated support 10. Specifically, multiple interlayer connection structures are evenly distributed along the circumference and axial direction of the support 10, ensuring the stability and uniformity of the support 10 in its overall structure. This enhances the mechanical strength of the support 10, enabling it to better withstand forces from all directions, and also improves the durability and reliability of the support 10.

[0064] Furthermore, by interlacing the braided units of the support layer 120 with those of the flow-blocking layer 110, the braided units of the support layer are partially interwoven across layers, so that the support layer 120 and the flow-blocking layer 110 are nested together, connecting the braided layer and the knitted layer together, which can avoid the possible separation of the two layers of the support 10 during use.

[0065] In one specific embodiment, the support layer 120 includes braided units arranged along a first braiding direction and braided units arranged along a second braiding direction. The braided units in the two braiding directions are interwoven to form a hollow column structure. The support layer 120, which is formed by interweaving metal braided units arranged in the first and second braiding directions, and where at least one braided unit is a braided strand composed of two or more metal braided wires twisted clockwise or counterclockwise, has improved flexibility and better resistance to local collapse of the support layer 120 compared to that prepared by a single braided unit in a conventional manner.

[0066] Furthermore, in this specific embodiment, as shown in FIG4(a), the knitting unit 121 and the knitting unit 122 of the support layer 120, which are arranged along the first knitting direction and along the second knitting direction, are inserted into the outside of the flow barrier layer 110 through the knitted mesh. Then, during the continued knitting process, a special Hock structure 130 is formed. Finally, the knitting unit 122 is inserted into the flow barrier layer 110 through the knitted mesh, forming an interlayer connection structure with a special structure in the support layer.

[0067] The braiding structure of the support layer includes, but is not limited to: regular braiding structures such as 1-press 1 braiding, spring braiding, interlocking structures (as shown in Figure 4(b)), Hock structures, etc.

[0068] As shown in Figure 2, each braided unit of the support layer 120 is composed of two parallel braided filaments. The support layer adopts a 1-over-1 braided structure: the intersection point formed by the interweaving of the braided unit of the support layer 120 and the braided unit of another braiding direction is located on the opposite side of this braided unit. The opposite side here can be understood as two adjacent intersection points formed by the interweaving of a braided unit with a braided unit of another braiding direction on one braided unit, one intersection point overlaps the inside of this braided unit, and the other intersection point overlaps the outside of this braided unit. That is, the braided units of different directions interweave with each other in a "1-over-1" pattern.

[0069] As shown in Figure 3, the spring weaving method involves the support layer being woven from braided units arranged along a first and second weaving direction, with at least one braided unit consisting of two or more twisted braids forming a strand. The strand can be formed before or during weaving. Specifically, a strand formed by twisting braids during weaving involves multiple braided units in the same direction first twisting each other to form a single braided strand, which is then interwoven with a braided strand in another direction to form the support layer 120. Specifically, the braided units in the strand twist each other clockwise or counterclockwise to form the braided strand, thereby improving the flexibility of the support layer 120 and providing better resistance to localized collapse of the support structure.

[0070] In one specific embodiment, as shown in Figures 5 and 6, the weaving method of the flow-blocking layer 110 includes warp knitting or weft knitting. The main advantages of warp knitting include: good warp dimensional stability. The warp-knitted flow-blocking layer 110 is formed by one or more sets of parallel knitting units simultaneously knitted into loops along the axial direction of the support and interlocked with each other. This makes its warp dimensions very stable, its texture soft, and its shape retention good. The main advantages of weft knitting include: good weft elasticity. The flow-blocking layer 110 is formed by one or more sets of parallel knitting units knitted into loops along the axial direction of the support and interlocked with each other. This makes its support circumferential elasticity very good, suitable for making flow-blocking layers 110 that require greater stretchability.

[0071] In one specific embodiment, the length of the support layer 120 in the axial direction of the stent 10 is greater than the length of the flow-blocking layer 110 in the axial direction of the stent 10. Both the support layer 120 and the flow-blocking layer 110 are hollow cylindrical structures. Since the flow-blocking layer 110 covers the support layer 120 and is coaxially arranged, the longer axial length of the support layer 120 can provide a wider range of support, ensuring that the stent 10 can firmly adhere to and support the blood vessel wall after implantation, especially at the bends or branches of the blood vessel, thereby enhancing the adaptability and stability of the stent 10 and effectively blocking or regulating blood flow without sacrificing the overall structural integrity of the stent 10.

[0072] Furthermore, the difference in axial length between the support layer 120 and the flow-blocking layer 110, through the structural design of the end of the support layer 120, such as the end flared structure, helps the stent 10 to be better anchored at the lesion location during implantation, better adapt to changes in blood vessels, reduce implantation difficulty, and improve the success rate of the surgery.

[0073] Since the flow-blocking layer 110 is coaxially arranged on the support layer 120, the outer diameter of the support layer 120 is smaller than the outer diameter of the flow-blocking layer 110.

[0074] In one specific embodiment, the number of heads in the support layer 120 is 2m, where 4 ≤ m ≤ 48, and the number of heads in the flow-blocking layer 110 is n, where n ≥ 1.

[0075] In one specific embodiment, the interlayer connection structure 200 is arranged at a frequency of 1 ≤ a ≤ 2 m in the circumferential direction of the support 10, and at a frequency of b in the axial direction of the support 10, where b = x * p, p is the weaving layer pitch, and x > 0.

[0076] In one specific embodiment, the metal coverage of the support layer 120 of the stent 10 is in the range of 10% to 40%, and the mesh size of the flow-blocking layer 110 is in the range of 20 micrometers to 200 micrometers. After the support layer 120 reaches the lesion site, the area of ​​the blood vessel covered by its braided units is controlled within a specific range, namely between 10% and 40%, which can provide sufficient mechanical support while allowing the flow-blocking layer 110 sufficient space to perform its function of blocking blood flow or other specific functions, achieving a balance between the two. The mesh size of the flow-blocking layer 110 is set in the range of 20 micrometers to 200 micrometers to ensure that the flow-blocking layer 110 can effectively block or regulate blood flow while allowing necessary fluid to pass through to maintain the normal physiological function of the blood vessel. The appropriate mesh size helps to reduce the stimulation of the blood vessel wall by the stent 10, reduce the risk of inflammatory response, and thus promote patient recovery.

[0077] In one specific embodiment, a metal ring is provided between the support layer 120 and the flow-blocking layer 110. The metal ring is a hollow tubular structure or a C-shaped tube, which covers the outside of the braided unit adjacent to the support layer 120 and the flow-blocking layer 110 to form an interlayer connection structure. The metal ring connects the support layer 120 and the flow-blocking layer 110 together to avoid interlayer separation that may occur during use.

[0078] Furthermore, the hollow metal ring is a cylindrical structure with an internal hollow interior and open ends. It is fixed by adhesive application and wrapped around the woven unit of the support layer 120 and the flow-blocking layer 110.

[0079] As shown in Figure 7, the hollow cylindrical metal ring is a cylindrical structure with a hollow interior and open ends, and a circular cross-section. The C-shaped metal ring is also a cylindrical structure with a hollow interior and open ends, and a C-shaped cross-section. The metal rings can be directly snapped onto the outside of the braided units of the support layer 120 and the flow-blocking layer 110. This tight wrapping not only enhances the strength of the connection points but also effectively prevents interlayer separation that may occur during use, thus greatly improving the reliability and safety of the stent 10. The metal rings firmly connect the support layer 120 and the flow-blocking layer 110 together. The interlayer connection structure formed by arranging the metal rings in a certain pattern along the circumference and axial direction of the stent is not only robust and durable but also distributes stress evenly, avoiding damage to the stent 10 caused by localized stress concentration. This provides continuous and stable support and treatment for patients, both in complex vascular environments and during long-term use.

[0080] In one specific embodiment, the braiding unit is a material with shape memory properties such as nickel-titanium or cobalt-chromium, or a DFT material containing radiopaque components, or a shape memory material such as nickel-titanium or cobalt-chromium and a radiopaque material such as platinum-tungsten or platinum-iridium, prepared alone or in combination.

[0081] In one specific embodiment, as shown in FIG8, the outer diameter of the covered stent 10 is in the range of 1.5~12mm, and the length is in the range of 10~80mm.

[0082] In one specific embodiment, the braiding units of the support layer 120 and the flow-blocking layer 110 are of one or more yarn diameters. The yarn diameter of the braiding units is in the range of 0.0005 inches to 0.00 inches. The yarn diameter of the braiding units of the support layer 120 is greater than or equal to the yarn diameter of the braiding units of the flow-blocking layer 110.

[0083] In one specific embodiment, as shown in Figure 8, the main body of the support layer 120 of the knitted covered stent 10 is a straight section structure, and the two axial ends of the support layer 120 are flared structures, which improves the opening ability and anchoring ability of the stent 10. The support layer 120 with flared structures at both ends not only gives the stent 10 a stronger expansion ability in the end region, making it easier for the stent 10 to open and conform to the blood vessel wall during implantation, thereby effectively reducing the difficulty of implantation and the risk of complications, but also significantly improves the anchoring performance of the stent 10, ensuring that the stent 10 can be firmly fixed in the required position, avoiding potential problems such as displacement or dislodgement, and further enhancing the safety and reliability of treatment.

[0084] Furthermore, the interlayer connection structure between the support layer 120 and the flow barrier layer 110 is formed by fixing adjacent braided units of the support layer 120 and the flow barrier layer 110 together with metal rings.

[0085] Furthermore, the end of the support layer 120 of the knitted film-coated bracket 10 can be a closed structure formed by winding, bundling and taking in the yarn, or binding the loose yarn together by mechanical clamping, welding, bonding, cylindrical hollow tubes or C-rings.

[0086] The two ends of the support layer 120 can be bound together by fully enclosed or partially enclosed yarn winding. The enclosed yarn winding technology is as follows: at the beginning or end of weaving, the total yarn ends w involved in weaving are first divided into ƞ weaving unit groups, and the number of yarn ends in each weaving unit group is w / ƞ, where ƞ can be 3, 4, 6, 8, 10, or 12; the ɛ group is further divided into two bundles, where ɛ is a natural number greater than 0 and ɛ≤ƞ; the two bundles are rotated in the same or opposite directions to form a stable yarn bundle, and then the two yarn bundles are bound together in parallel to form a closed yarn winding group. The characteristics of the closed yarn winding group are shown in Figure 9 below. They are fixed together by means of glue application, welding, etc. (a metal ring can be placed on the outside to avoid insufficient adhesion or welding strength). The support layer 120 of the knitted coated support 10 has a partially closed, fully closed, or loose structure at its ends. The closed structure can be achieved through methods such as backwinding, bundling and finishing, welding, or bonding. Backwinding and finishing structures can be threaded between the loops at the ends of the knitted layer. Axial schematic diagrams of bundling and backwinding of the support layer 120 are shown in Figures 11 and 12. Based on the above, the partially closed or fully closed structure formed by bundling and backwinding can have flush ends or staggered arrangements, as shown in Figure 13. The flow-blocking layer 110 of the knitted coated support 10, as shown in Figure 14, has loose filament ends that can be fixed by methods such as glue application or welding, or wound around the knitting yarn of the support layer 120. Furthermore, to further enhance the stability and reliability of the connection, auxiliary components such as hollow rings, C-rings, and various irregularly shaped rings can be used. These components are achieved through moderate external pressure, mechanical clamping, or advanced processes such as glue application and welding, as shown in Figure 7. It can ensure a firm and tight connection between the knitted yarn ends of the flow barrier layer 110 and the support structure, improve the overall performance of the bracket 10, and also ensure its stability and durability in complex environments.

[0087] Based on the above, at the start or end of weaving, the total number of yarn ends w is first divided into ƞ weaving unit groups, with each weaving unit group containing yarn ends w / ƞ, where ƞ can be 3, 4, 6, 8, 10, or 12. The ɛ group is further divided into two bundles, where ɛ is a natural number greater than 0 and ɛ≤ƞ. The two bundles of weaving units rotate in the same or opposite directions to form stable yarn bundles, which are then bound together in parallel to form a take-up group.

[0088] In one specific embodiment, the wire take-up assembly of the support layer 120 can be fixed by welding.

[0089] In one specific embodiment, the end of the support layer 120 contains x-ray resistant hollow precious metal tubes, numbering ɛ, which can be connected to the braided unit by bonding, welding or mechanical pressing.

[0090] In one specific embodiment, the end of the support layer 120 may adopt a full or partial wrap structure design, dividing the w braided units into w / 2 groups, and two adjacent braided units with different helical directions are called wrap groups.

[0091] In one specific embodiment, both the take-up group and the rewinding group can be staggered.

[0092] In one specific embodiment, the flow-blocking layer 110 of the knitted coated support 10, as shown in Figure 14, has loosely attached filaments that can be fixed by methods such as adhesive application or welding, or wrapped around the braided filaments of the support layer 120. Furthermore, to further enhance the stability and reliability of the connection, auxiliary components such as hollow rings, C-rings, and various irregularly shaped rings can be used. These components are secured by appropriate external pressure, mechanical clamping, or advanced processes such as adhesive application and welding, as shown in Figure 7. This ensures a firm and tight connection between the knitted filaments of the flow-blocking layer 110 and the support structure, improving the overall performance of the support 10 and ensuring its stability and durability in complex environments.

[0093] A preparation method for preparing a covered scaffold includes the following steps:

[0094] S100. The support layer 120 is obtained by weaving using the braiding unit through a weaving process;

[0095] In this step, high-quality braided units are used as raw materials to construct the support layer 120 of the bracket 10 through braiding technology. The support layer 120 provides the necessary strength and stability to ensure the reliability and durability of the bracket 10 in complex environments.

[0096] S200. Using a knitting unit along the outer surface of the support layer 120, the flow-blocking layer is knitted through a knitting process, and during the knitting process, the knitting unit is knitted and interwoven regularly in the support layer 120 to obtain the flow-blocking layer 110, forming a knitted film-coated support 10 with interlayer connection.

[0097] In this step, knitting units are regularly interwoven into the support layer 120 on the outer surface of the support layer 120, which can tightly fix the knitting units of the flow barrier layer 110 onto the support layer 120, thereby obtaining a knitted film-coated bracket 10 with interlayer connections.

[0098] S300, Heat treatment is performed on the knitted coated bracket 10 for shaping;

[0099] In this step, the knitted coated support 10 is heat-treated for shaping, eliminating internal stresses that may be generated during weaving and knitting, making the structure of the support 10 more stable, and also enhancing the strength and toughness of the knitted units, thereby improving the durability and service life of the support 10. Importantly, by precisely controlling the temperature and time of the heat treatment, it can be ensured that the support 10 maintains its original shape and size after shaping.

[0100] The various embodiments of this application have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A knitted covered stent, characterized by, include: Support layer and flow barrier layer The support layer is woven from braided units, forming a hollow columnar braided structure. The flow-blocking layer is a knitted structure that is formed by knitting units looping together and continuously knitting into a net, covering the outside of the support layer. The inner side of the flow-blocking layer is attached to the outer side of the support layer, and there is an interlayer connection structure between the support layer and the flow-blocking layer to achieve interlayer connection and fixation between the support layer and the flow-blocking layer. At least one metal braided unit of the support layer is inserted out of the braided structure of the flow-blocking layer along the knitted mesh, and then inserted into the braided structure of the flow-blocking layer along the knitted mesh to form an interlayer connection structure between the support layer and the flow-blocking layer. The metal coverage of the support layer is in the range of 10% to 40%; the grid size of the flow-blocking layer is in the range of 20 micrometers to 200 micrometers.

2. The knitted covered stent of claim 1, wherein, The interlayer connection structure comprises multiple structures, which are evenly distributed along the circumference and axial direction of the knitted film-coated bracket.

3. The knitted covered stent of claim 1, wherein, The support layer includes braided units arranged along a first braiding direction and braided units arranged along a second braiding direction. The braided units in the two braiding directions are interwoven to form a hollow columnar structure.

4. The knitted covered stent of claim 1, wherein, The flow-blocking layer is woven using warp knitting or weft knitting techniques.

5. The knitted covered stent of claim 1, wherein, The length of the support layer along the axial direction of the bracket is greater than the length of the flow-blocking layer along the axial direction of the bracket.

6. The knitted covered stent of claim 1, wherein, The outer diameter of the support layer is smaller than the outer diameter of the flow-blocking layer.

7. The knitted covered stent of claim 1, wherein, The number of yarn ends in the braided unit of the support layer is 2m, and 4≤m≤48; The number of yarn ends in the braided unit of the flow-blocking layer is n, where n≥1.

8. The knitted covered stent of claim 7, wherein, The interlayer connection structure is laid out at a frequency of a in the circumferential direction of the support, where 1≤a≤2m; The interlayer connection structure is laid out at a frequency of b along the axial direction of the support, where b = x * p, p is the weaving layer pitch, and x > 0.

9. The knitted covered stent of claim 1, wherein, The cross-section of the braided unit includes irregularly shaped structures such as circles, triangles, or hollow rings.

10. The knitted covered stent of claim 1, wherein, The braided unit is made of a material with shape memory properties, or a material containing radiopaque components, or a mixture of a material with shape memory properties and a material containing radiopaque components.

11. The knitted covered stent of claim 1, wherein, The outer diameter of the covered stent is in the range of 1.5~12mm, and the length is in the range of 10~80mm.

12. The knitted covered stent of claim 1, wherein, When starting or ending weaving, the total number of yarn ends w involved in the weaving is first divided into ƞ weaving yarn groups. The number of yarn ends in each weaving yarn group is w / ƞ, where ƞ can be 3, 4, 6, 8, 10, or 12. The group ɛ is further divided into two equal bundles, where ɛ is a natural number greater than 0 and ɛ≤ƞ; the two bundles are divided along the same direction. Alternatively, they can rotate in opposite directions to form a stable bundle of filaments, and the two bundles of filaments are bound together in parallel to form a closed take-up group.

13. The knitted covered stent of claim 12, wherein, The ends of the support layer are partially closed, fully closed, or loose structures. The ends of the support layer are formed into a partially or fully enclosed structure by means of winding, bundling, welding or bonding.

14. The knitted covered stent of claim 1, wherein, The braiding units of the support layer and the flow-blocking layer are of one filament diameter or a mixture of multiple filament diameters; The yarn diameter of the braiding unit is in the range of 0.0005 inches to 0.005 inches; The diameter of the braided unit of the support layer is greater than or equal to the diameter of the braided unit of the flow-blocking layer.

15. A method for producing a knitted covered stent for producing the covered stent according to any one of claims 1 to 14, characterized in that, Includes the following steps: knitting the support layer by using the knitting unit through a knitting process; knitting the flow resistance layer along the outer surface of the support layer through a knitting process, and regularly inserting the knitting unit into the support layer during the knitting process to obtain the flow resistance layer, thereby forming a knitted covered stent with interlayer connection; heat treating and shaping the knitted covered stent.

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