Knitted covered stent

Abstract

The knitted covered stent comprises a supporting layer and a flow choking layer, the supporting layer is formed by knitting knitting units and is of a hollow cylinder knitting structure, the flow choking layer is formed by knitting knitting units, the supporting layer serves as a basic framework of the stent and provides necessary mechanical support, and the flow choking layer is of a knitting structure covering the supporting layer. Wherein the flow blocking layer adopts a knitting technology, knitting units are made to be looped in a penetrating and sleeving mode and continuously knitted into a net to cover the supporting layer, the inner side of the flow blocking layer is attached to the outer side of the supporting layer, the knitted covered stent of the knitted structure and the knitted structure is obtained, an interlayer connecting structure exists between the supporting layer and the flow blocking layer, and interlayer connecting and fixing of the supporting layer and the flow blocking layer are achieved; compared with a traditional design of cutting a skeleton and a polymeric membrane, the stent shows more excellent adherence and compliance, and can better adapt to the form and change of a blood vessel, so that the implantation effect and the treatment effect of the stent are improved.

Description

Technical Field

[0001] The present application relates to the field of medical device technology, and in particular to a knitted coated stent. Background Art

[0002] Minimally invasive interventional surgery is a common treatment for intracranial aneurysms. For the treatment of intracranial aneurysms, the commonly used techniques currently include coil packing, stent-assisted coil packing, blood flow diversion device placement, covered stent implantation, and other methods. For large and giant saccular aneurysms, wide-necked aneurysms, fusiform and dissecting aneurysms, if traditional coil or stent-assisted coil packing techniques are used, there are problems such as long intraoperative time, incomplete aneurysm occlusion, and high postoperative complication rate. The blood flow diversion device, due to its high weaving density, may also have incomplete wall adhesion and bending flexibility, which has a certain impact on the postoperative aneurysm occlusion rate and the occurrence of ischemic complications. Summary of the Invention

[0003] In view of this, the present application proposes a knitted coated stent.

[0004] According to one aspect of the present application, a knitted stent graft is provided, comprising: a support layer and a flow-blocking layer,

[0005] The support layer is woven from weaving units and has a hollow cylindrical weaving structure;

[0006] The flow-blocking layer is a knitted structure in which the weaving units are looped and continuously woven into a net through a knitting process, 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, thereby realizing the interlayer connection and fixation between the support layer and the flow-blocking layer.

[0007] In one possible implementation, at least one metal braiding unit of the support layer is inserted out of the braiding structure of the flow-blocking layer along the knitted mesh, and then inserted into the braiding 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.

[0008] In a possible implementation, metal rings are used between the support layer and the flow-blocking layer to connect adjacent woven units of the support layer and woven units of the flow-blocking layer, thereby forming an interlayer connection structure between the support layer and the flow-blocking layer.

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

[0010] There are multiple interlayer connection structures, which are evenly distributed along the circumference and axial direction of the knitted coated stent.

[0011] In a possible implementation, the support layer includes weaving units arranged along a first weaving direction and weaving units arranged along a second weaving direction, and the weaving units in the two weaving directions are interwoven to form a hollow columnar structure.

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

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

[0014] In a possible implementation manner, the outer diameter of the supporting layer is smaller than the outer diameter of the flow-blocking layer.

[0015] In a possible implementation, the number of wire ends of the braiding unit of the support layer is 2m, 4≤m≤48;

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

[0017] In a possible implementation, the arrangement frequency of the interlayer connection structure in the circumferential direction of the stent is a, 1≤a≤2m;

[0018] The arrangement frequency of the interlayer connection structure in the axial direction of the stent is b, b=x*p, p is the braiding layer pitch, and x>0.

[0019] In one possible implementation, the metal coverage of the knitted stent graft 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 microns to 200 microns.

[0021] In a 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 fixes the braided units of the support layer and the flow-blocking layer together at the interlayer connection structure.

[0023] In one possible implementation, the cross-section of the braided unit includes but is not limited to special-shaped structures such as a circle, a triangle, and a hollow ring;

[0024] In one possible implementation, the braided unit is made of a material with shape memory properties such as nickel titanium, cobalt chromium, or a DFT material containing a radiopaque component, or a shape memory material such as nickel titanium, cobalt chromium and a radiopaque material such as platinum tungsten, platinum iridium, etc., prepared separately or in combination.

[0025] In one possible implementation, the outer diameter of the stent graft 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 beginning or end of weaving, the total number of yarns w involved in weaving is first divided into n weaving yarn groups, the number of yarns in each weaving yarn group is w / n, and n can be 3, 4, 6, 8, 10, or 12;

[0027] The ε group is further divided into two bundles, where ε is a natural number greater than 0, and ε≤η; the two equally divided bundles rotate in the same direction or opposite directions to form stable yarn bundles, and the two yarn bundles are bound together in parallel to form a closed yarn collection group.

[0028] In one possible implementation, the end of the support layer is a partially closed structure, a fully closed structure, or a loose structure;

[0029] The end of the support layer can be formed into a partially closed or fully closed structure by winding, splitting and tailing, welding or bonding.

[0030] In a possible implementation, the braided units of the support layer and the flow-blocking layer have a single wire diameter or a mixture of multiple wire diameters;

[0031] The wire diameter of the braiding unit ranges from 0.0005 inches to 0.005 inches;

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

[0033] A method for preparing a knitted covered stent, comprising the following steps:

[0034] Using the weaving unit to weave the support layer through a weaving process;

[0035] The flow-blocking layer is knitted along the outer surface of the support layer by a knitting process, and the knitting units are regularly interspersed in the support layer during the knitting process to obtain the flow-blocking layer and form a knitted stent graft with interlayer connection;

[0036] The knitted stent graft is subjected to heat treatment to be shaped.

[0037] The beneficial effects of the knitted coated stent of the embodiment of the present application are as follows: the knitted coated stent uses the support layer as the core carrier, and the flow-blocking layer as the coating layer, the woven units of the support layer are interspersed inside and outside the flow-blocking layer to form an interlayer connection structure, or a hollow tubular or C-shaped tubular metal ring is used to connect the woven units of the support layer and the flow-blocking layer to form an interlayer connection structure, so as to achieve the interlayer connection and fixation of the support layer 120 and the flow-blocking layer 110, or directly adopt welding, leaching, and gluing to form an interlayer connection structure, so as to achieve a tight and firm connection between the support layer and part of the flow-blocking layer, so as to prevent the problem of interlayer separation that may occur in the use of the stent, thereby ensuring the long-term stability and reliability of the stent. Among them, compared with the traditional coated stent, the flow-blocking layer as the coating layer in the present invention does not exist as just a thin film without mechanical properties. Both the flow-blocking layer and the support layer are carefully made of woven units with shape memory effect. In addition, the support layer is woven and the flow-blocking layer is knitted to obtain a woven structure + knitted structure knitted covered stent. Compared with the traditional cut skeleton + polymer membrane design, it shows more excellent wall adhesion and compliance, and can better adapt to the morphology and changes of blood vessels, thereby improving the implantation effect and therapeutic effect of the stent.

[0038] Other features and aspects of the present application will become apparent from the following detailed description of exemplary embodiments with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0040] Figure 1 A schematic diagram showing the main structure of a knitted stent graft according to an embodiment of the present application is shown;

[0041] Figure 2 A schematic diagram showing the interlayer connection structure of a knitted stent graft according to an embodiment of the present application is shown;

[0042] Figure 3 Another schematic diagram showing the interlayer connection structure of the knitted stent graft according to an embodiment of the present application;

[0043] Figure 4 A schematic diagram showing the interlayer connection structure of the knitted stent graft of an embodiment of the present application, wherein the support layer contains a special structure;

[0044] Figure 5 A schematic diagram showing the weft knitted structure of the flow-blocking layer of the knitted stent graft according to an embodiment of the present application;

[0045] Figure 6 A schematic diagram showing the warp knitted structure of the flow-blocking layer of the knitted coated stent according to an embodiment of the present application;

[0046] Figure 7 A schematic diagram showing a cross-sectional structure of a metal ring in an embodiment of the present application, wherein a hollow cylindrical or C-shaped metal ring connects the support layer and the flow-blocking layer to form an interlayer connection structure;

[0047] Figure 8 A schematic diagram showing the overall effect of the stent in which the metal ring connects the support layer and the flow-blocking layer to form an interlayer connection structure according to an embodiment of the present application;

[0048] Figure 9 A schematic diagram showing the structure of a closed wire collection group of a knitted stent graft according to an embodiment of the present application is shown;

[0049] Figure 10 A schematic diagram illustrating a method for fixing a closed wire collection group structure of a knitted stent graft according to an embodiment of the present application;

[0050] Figure 11 A schematic diagram showing the structure of the bundled and tailed end portion of the support layer in an embodiment of the present application is shown;

[0051] Figure 12 A schematic diagram showing the structure of the end portion of the support layer of an embodiment of the present application being wound back;

[0052] Figure 13 A schematic diagram showing the structure of the support layer end portion bundled and tailed and the end portion wrapped and staggered in layers in an embodiment of the present application;

[0053] Figure 14 A schematic diagram showing the structure of the loose wire ends at the end of the flow-blocking layer in an embodiment of the present application being connected and fixed; DETAILED DESCRIPTION

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

[0055] It should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like, indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention or simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting 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 the technical features being referred to. Thus, a feature identified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0057] The word “exemplary” is used exclusively herein to mean “serving as an example, example, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments.

[0058] In addition, numerous specific details are provided in the detailed description below to better illustrate the present application. Those skilled in the art will appreciate that the present application can be practiced without certain specific details. In some instances, methods, means, components, and circuits well known to those skilled in the art are not described in detail in order to highlight the main purpose of the present application.

[0059] like Figure 1 As shown, the knitted coated stent 10 of the embodiment of the present application includes: a support layer 120 and a flow-blocking layer 110, the support layer 120 is a woven structure woven by weaving units and is a hollow cylindrical structure; the flow-blocking layer 110 is knitted by weaving units, wherein the support layer 120 serves as the basic skeleton of the stent 10 and provides necessary mechanical support, and the flow-blocking layer 110 is a knitted structure covering the outside of the support layer 120, wherein the flow-blocking layer 110 is a knitted structure covering the outside of the support layer 120 using a more delicate knitting process, and the weaving units are knitted 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, and the weaving units of the support layer 120 are interspersed inside and outside the flow-blocking layer 110 to form an interlayer connection structure, thereby realizing the interlayer connection and fixation between the support layer 120 and the flow-blocking layer 110.

[0060] In this embodiment, the knitted stent graft 10 of the present invention uses the support layer 120 as the core carrier, and the flow-blocking layer 110 as the coating layer. The woven units of the support layer 120 are interspersed inside and outside the flow-blocking layer 110 to form an interlayer connection structure, or a hollow tubular or C-shaped tubular metal ring is used to connect the woven units of the support layer and the flow-blocking layer to form an interlayer connection structure to achieve interlayer connection and fixation between the support layer 120 and the flow-blocking layer 110, or directly adopt welding, leaching, or gluing to achieve a tight and firm connection between the support layer 120 and the flow-blocking layer 110 at some positions. This can prevent the interlayer separation problem that may occur in the stent 10 during use, thereby ensuring the long-term stability and reliability of the stent 10. Compared with the traditional coated stent 10, the flow-blocking layer 110 as 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 of woven units with shape memory effect. In addition, the support layer 120 is woven and the flow-blocking layer 110 is knitted to obtain a woven structure + knitted structure knitted coated stent 10. Compared with the traditional cut skeleton + polymer film design, it shows more excellent wall adhesion and compliance, and can better adapt to the morphology and changes of blood vessels, thereby improving the implantation effect and therapeutic effect of the stent 10.

[0061] Furthermore, the application of knitted structure as a covering layer has greater flexibility and adaptability than traditional polymer membranes. By cleverly combining knitted coils of different sizes, especially designing large knitted coils to cover branch blood vessels, the occlusion problem of branch blood vessels can be effectively avoided.

[0062] In a specific embodiment, at least one weaving unit of the support layer 120 is inserted out of the weaving structure of the flow-blocking layer 110 along the knitted mesh, and then inserted into the weaving 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 woven units of the support layer 120 inside and outside the flow-blocking layer 110 at a local position of the stent 10, the ability of the interlayer connection structure 200 to resist deformation is increased. After the external force is applied, the flow-blocking layer 110 and the support layer 120 are nested with each other near these interlayer connection structures 200, thereby avoiding the risk of interlayer separation caused by the difference in deformation recovery ability of the flow-blocking layer 110 and the support layer 120 after the external force is released near the interlayer connection structure 200. Even if the flow-blocking layer 110 and the support layer 120 produce a certain displacement when the external force is applied, the flow-blocking layer 110 can return to its original position relatively quickly under the drive of the support layer 120 with relatively large rigidity, further resisting the risk of local delamination of the stent 10, and the interlayer connection structures 200 distributed throughout the stent 10 further increase the overall ability of the stent 10 to resist delamination.

[0063] Furthermore, in this specific embodiment, an interlayer connection structure 200 exists between the support layer 120 and the flow-blocking layer 110. There are multiple interlayer connection structures 200, which are evenly distributed along the circumference and axial directions of the coated stent 10. Specifically, the multiple interlayer connection structures are evenly distributed along the circumference and axial directions of the stent 10, and the uniform arrangement ensures the stability and uniformity of the overall structure of the stent 10, thereby enhancing the mechanical strength of the stent 10, enabling it to better withstand forces from all directions, and also improving the durability and reliability of the stent 10.

[0064] Furthermore, by interweaving the weaving units of the support layer 120 inside and outside the flow-blocking layer 110, the support layer weaving units are partially cross-layered, so that the support layer 120 and the flow-blocking layer 110 are nested with each other, and the weaving layer and the knitted layer are connected together, which can avoid the inter-layer separation that may occur between the two layers of the bracket 10 during use.

[0065] In one embodiment, the support layer 120 includes braided units arranged along a first braiding direction and braided units arranged along a second braiding direction, and the braided units in the two braiding directions are interwoven to form a hollow cylindrical structure. The support layer 120 is formed by interweaving metal braided units arranged in two directions, the first braiding direction and the second braiding direction, and the braided units in at least one direction are braided wire strands composed of two or more metal braided wires twisted clockwise or counterclockwise. Compared with the metal braided wire strands prepared by conventional methods using a single braided unit, the metal braided wire strands formed by the clockwise or counterclockwise braided units have improved flexibility and better resistance to local collapse of the stent.

[0066] Furthermore, in this specific embodiment, Figure 4 As shown in (a), the weaving units 121 of the support layer 120 arranged along the first weaving direction and the weaving units 122 arranged along the second weaving direction are inserted into the flow-blocking layer 110 along the knitted mesh holes of the flow-blocking layer 110, and then a special Hock structure 130 is formed in the process of continuing weaving. Finally, the Hock structure 130 is inserted into the flow-blocking layer 110 along the knitted mesh holes of the flow-blocking layer 110, forming an interlayer connection structure containing a special structure of the support layer.

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

[0068] Among them, Figure 2As shown, the weaving units of the support layer 120 are composed of two parallel weaving wires, and the support layer adopts a 1-on-1 weaving structure: the intersections formed by the weaving units of the support layer 120 and the weaving units of another weaving direction are located on the opposite side of this weaving unit due to the interweaving. The opposite side here can be understood as two adjacent intersections formed by interweaving with the weaving units of another weaving direction on a weaving unit, one of which is overlapped on the inner side of this weaving unit, and the other is overlapped on the outer side of this weaving unit, that is, the weaving units in different directions are interwoven with each other in a "1-on-1" pattern.

[0069] Among them, Figure 3 As shown, the spring weaving method is as follows: the support layer is woven by weaving units arranged along the first weaving direction and the second weaving direction, and the weaving units in at least one direction are woven strands formed by twisting two or more weaving wires. The woven strands can be formed before weaving or during the weaving process. The woven strands twisted during the weaving process specifically refer to: multiple weaving units in the same direction are first twisted with each other, that is, twisted to a certain extent to form a weaving unit woven strand, and then interwoven with the weaving unit woven strand in the other direction to form the support layer 120. Specifically, the weaving units in the woven strands are twisted with each other clockwise or counterclockwise to form woven strands, so that the flexibility of the support layer 120 woven by the woven strands is improved, and at the same time, it has a better ability to resist local collapse of the stent.

[0070] In a specific embodiment, if Figure 5 and Figure 6 As shown, 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 made up of one or more groups of parallel weaving units that are woven into loops along the axial direction of the stent and interwoven with each other, which makes its warp dimensional stability very stable, soft in texture, and has good shape retention. The main advantages of weft knitting include: good weft elasticity. The flow-blocking layer 110 is made up of one or more groups of parallel weaving units that are woven into loops along the axial direction of the stent and interwoven with each other, which makes its stent circumferential elasticity very good, suitable for making a flow-blocking layer 110 that requires greater stretchability.

[0071] In a specific embodiment, the axial length of the support layer 120 in the stent 10 is greater than the axial length of the flow-blocking layer 110 in the stent 10. The support layer 120 and the flow-blocking layer 110 are both hollow cylindrical structures. Since the flow-blocking layer 110 is coaxially arranged on the support layer 120, the longer axial length of the support layer 120 can provide a wider support range, 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 vessels, 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 trumpet structure, helps the stent 10 to better anchor at the lesion location during the implantation process, better adapt to changes in blood vessels, reduce the difficulty of implantation, and improve the success rate of the operation.

[0073] Since the blocking layer 110 is coaxially arranged to cover the supporting layer 120 , the outer diameter of the supporting layer 120 is smaller than the outer diameter of the blocking layer 110 .

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

[0075] In a specific embodiment, the circumferential arrangement frequency of the interlayer connection structure 200 in the stent 10 is a, 1≤a≤2m, and the axial arrangement frequency of the interlayer connection structure 200 in the stent 10 is b, b=x*p, p is the braiding layer pitch, x>0.

[0076] In a 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 microns to 200 microns. After the support layer 120 reaches the lesion site, the area of ​​the blood vessel covered by its woven units is controlled within a specific range, i.e., between 10% and 40%, which can provide sufficient mechanical support while allowing the flow-blocking layer 110 to have enough space to perform its blood flow blocking 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 microns to 200 microns, ensuring that the flow-blocking layer 110 can effectively block or regulate blood flow while allowing necessary fluids to pass through to maintain the normal physiological function of the blood vessels. The appropriate mesh size helps reduce the irritation of the stent 10 on the blood vessel wall, reduces the risk of inflammatory response, and thus promotes the patient's recovery.

[0077] In a 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 is wrapped around the outside of the woven unit adjacent to the support layer 120 and the flow-blocking layer 110 to form an interlayer connection structure. The metal ring is used to connect the support layer 120 and the flow-blocking layer 110 together to avoid interlayer separation that may occur between the two layers during use.

[0078] Furthermore, the metal ring with a hollow structure is a cylindrical structure with a hollow interior and open ends, and is fixed by glue point and wrapped around the outside of the braided unit of the support layer 120 and the flow-blocking layer 110 .

[0079] Among them, Figure 7As shown, the hollow cylindrical metal ring is a cylindrical structure with a hollow interior and open ends, and its cross section is circular. The C-shaped metal ring is a cylindrical structure with a hollow interior and open ends, and its cross section is a "C"-shaped structure. The metal ring can be directly clamped and wrapped around the outside of the woven unit of the support layer 120 and the flow-blocking layer 110. The tight wrapping not only enhances the strength of the connection point, but also effectively prevents the interlayer separation phenomenon that may occur during use, thereby greatly improving the reliability and safety of the stent 10. The metal ring firmly connects 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 in the circumferential and axial directions of the stent is not only strong and durable, but also can evenly distribute stress, avoiding damage to the stent 10 due to local stress concentration, providing continuous and stable support and treatment for patients, whether in a complex vascular environment or in long-term use.

[0080] In a specific embodiment, the braided unit is made of a material with shape memory properties such as nickel titanium, cobalt chromium, or a DFT material containing a radiopaque component, or a shape memory material such as nickel titanium, cobalt chromium and a radiopaque material such as platinum tungsten, platinum iridium, etc., prepared separately or in combination.

[0081] In a specific embodiment, if Figure 8 As shown, the outer diameter of the stent graft 10 is in the range of 1.5 to 12 mm, and the length is in the range of 10 to 80 mm.

[0082] In a specific embodiment, the weaving units of the support layer 120 and the flow-blocking layer 110 have a single wire diameter or a mixture of multiple wire diameters, and the wire diameter of the weaving units ranges from 0.0005 inches to 0.00 inches. The wire diameter of the weaving units of the support layer 120 is greater than or equal to the wire diameter of the weaving units of the flow-blocking layer 110.

[0083] In a specific embodiment, if 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 trumpet-shaped structures, which improve the end opening ability and anchoring ability of the stent 10. The support layer 120 with trumpet-shaped structures at both ends not only gives the stent 10 a stronger expansion ability in the end area, making it easier for the stent 10 to open and adhere to the blood vessel wall during implantation, thereby effectively reducing the difficulty of implantation and the risk of complications, but also the trumpet-shaped structure significantly improves the anchoring performance of the stent 10, ensuring that the stent 10 can be firmly fixed in the desired position, avoiding potential problems such as displacement or falling off, and further enhancing the safety and reliability of treatment.

[0084] Furthermore, the interlayer connection structure of the support layer 120 and the flow-blocking layer 110 is formed by fixing adjacent woven units of the support layer 120 and the flow-blocking layer 110 together through metal rings.

[0085] Furthermore, the end of the support layer 120 of the knitted coated stent 10 can be a closed structure formed by winding, bundled wire, or by mechanical clamping, welding, bonding, cylindrical hollow tube or C-ring to bind loose wires together.

[0086] Among them, the two ends of the supporting layer 120 can be bound together by fully closed wire gathering or partially closed wire gathering. The closed wire gathering technology is: when starting or ending weaving, the total wire heads w involved in weaving are first divided into η weaving unit groups, and the number of wire heads in each weaving unit group is w / η, and η can be 3, 4, 6, 8, 10, or 12; the ε group is further divided into two bundles, ε is a natural number greater than 0, and ε≤η; the two equally divided bundles rotate in the same direction or opposite directions to form a stable wire bundle, and then the two bundles are bound together in parallel to form a closed wire gathering group. The characteristics of the closed wire gathering group are as follows Figure 9 As shown, they are fixed together by dispensing glue, welding, etc. (a metal ring can be set on the outside to avoid insufficient bonding or welding strength). The support layer 120 of the knitted stent graft 10 has a partially closed structure, a fully closed structure or a loose structure at its end. The closed structure can be achieved by winding, splitting and ending, welding, bonding, etc. The winding and ending structures can be worn between the coils at the end of the knitted layer. The axial schematic diagram of the support layer 120 splitting and ending and winding is shown in FIG. Figure 11 and Figure 12 Based on the above, the ends of the partially closed or fully closed structure formed by the beam splitting and winding can be flush or staggered. The staggered arrangement effect is as follows: Figure 13 As shown. The flow-blocking layer 110 of the knitted stent graft 10 is as shown. Figure 14 The loose wire ends can be fixed by dispensing glue, welding, etc., or wound around the braided wire of the support layer 120; In addition, in order to further enhance the stability and reliability of the connection, auxiliary elements such as hollow rings, C-shaped rings and various special-shaped rings can be used. These elements can be squeezed by external force, mechanically clamped, or supplemented by advanced process means such as dispensing glue, welding, etc. Figure 7 It can ensure a firm and tight connection between the knitted yarn heads of the flow-blocking layer 110 and the supporting structure, improve the overall performance of the stent 10, and ensure its stability and durability in complex environments.

[0087] According to the above, at the beginning or end of weaving, the total number of yarns w involved in the weaving is first divided into n weaving unit groups, where the number of yarns in each weaving unit group is w / n, where n can be 3, 4, 6, 8, 10, or 12. The ε group is further divided into two bundles, where ε is a natural number greater than 0, and ε ≤ η. The two equally divided weaving unit bundles rotate in the same or opposite directions to form a stable yarn bundle. The two yarn bundles are then bundled together in parallel to form a yarn collection group.

[0088] In one specific embodiment, the wire collection group 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-opaque noble metal hollow tubes, the number of which is ε. The noble metal hollow tubes can be connected to the braiding unit by bonding, welding or mechanical crimping.

[0090] In one specific embodiment, the end of the support layer 120 can adopt a full-wrap or partial-wrap structure design, and the w braided units are divided into w / 2 groups, and two adjacent braided units with inconsistent rotation directions are a wrapping group.

[0091] In one specific embodiment, the wire collection group and the rewinding group can be distributed in staggered layers.

[0092] In a specific embodiment, the flow-blocking layer 110 of the knitted stent graft 10 is as follows: Figure 14 The loose wire ends can be fixed by dispensing glue, welding, etc., or wound around the braided wire of the support layer 120; In addition, in order to further enhance the stability and reliability of the connection, auxiliary elements such as hollow rings, C-shaped rings and various special-shaped rings can be used. These elements can be squeezed by external force, mechanically clamped, or supplemented by advanced process means such as dispensing glue, welding, etc. Figure 7 It can ensure a firm and tight connection between the knitted yarn heads of the flow-blocking layer 110 and the supporting structure, improve the overall performance of the stent 10, and ensure its stability and durability in complex environments.

[0093] A preparation method for preparing a stent graft comprises the following steps:

[0094] S100, using the weaving unit to weave a support layer 120 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 stent 10 through braiding technology. The support layer 120 provides the necessary strength and stability to ensure the reliability and durability of the stent 10 in complex environments.

[0096] S200, using weaving units along the outer surface of the support layer 120 to weave the flow-blocking layer by a knitting process, and during the weaving process, the weaving units are regularly knitted and interspersed in the support layer 120 to obtain the flow-blocking layer 110, forming a knitted stent graft 10 with interlayer connection;

[0097] In this step, the braided units are regularly knitted and interspersed in the support layer 120 on the outer surface of the support layer 120, so that the braided units of the flow-blocking layer 110 can be tightly fixed on the support layer 120 to obtain a knitted stent graft 10 with interlayer connection.

[0098] S300, performing heat treatment on the knitted stent graft 10 to finalize the shape;

[0099] In this step, the knitted stent graft 10 is heat-treated to finalize its shape. This eliminates any internal stress that may have occurred during the braiding and knitting process, making the structure of the stent 10 more stable. It also enhances the strength and toughness of the braided units, improving the durability and service life of the stent 10. Importantly, by precisely controlling the temperature and duration of the heat treatment, the stent 10 is ensured to maintain its original shape and size after finalization.

[0100] The embodiments of the present application have been described above. The above description is illustrative and not exhaustive, and is not 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 selected to best explain the principles of the embodiments, their practical applications, or improvements to the technology in the market, or to enable other persons skilled in the art to understand the embodiments disclosed herein.

Claims

1. A knitted stent graft, characterized in that: include: Support layer and blocking layer, The support layer is woven from woven units and presents a hollow cylindrical woven structure; The flow-blocking layer is a knitted structure in which a weaving unit is looped and continuously woven into a net through a knitting process, and covers the outside of the supporting layer. The inner side of the flow-blocking layer is attached to the outer side of the supporting layer, and there is an interlayer connection structure between the supporting layer and the flow-blocking layer, so as to realize the interlayer connection and fixation between the supporting layer and the flow-blocking layer.

2. The knitted stent graft according to claim 1, characterized in that: 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.

3. The knitted stent graft according to claim 1, characterized in that: Between the support layer and the flow-blocking layer, adjacent woven units of the support layer and woven units of the flow-blocking layer are connected together through metal rings to form an interlayer connection structure between the support layer and the flow-blocking layer.

4. The knitted stent graft according to claims 1-3, characterized in that: There is an interlayer connection structure between the support layer and the flow-blocking layer; There are multiple interlayer connection structures, which are evenly arranged along the circumference and axial direction of the knitted coated stent.

5. The knitted stent graft according to claim 1, characterized in that: The support layer comprises a weaving unit arranged along a first weaving direction and a weaving unit arranged along a second weaving direction, and the weaving units in the two weaving directions are interwoven to form a hollow column structure.

6. The knitted stent graft according to claims 1-3, characterized in that: The flow-blocking layer is knitted by warp knitting or weft knitting.

7. The knitted stent graft according to claim 1, characterized in that: The length of the support layer in the axial direction of the stent is greater than the length of the flow-blocking layer in the axial direction of the stent.

8. The knitted stent graft according to claim 1, characterized in that: The outer diameter of the supporting layer is smaller than the outer diameter of the flow-blocking layer.

9. The knitted stent graft according to claim 1, characterized in that: The number of wire heads of the braiding unit of the support layer is 2m, 4≤m≤48; The number of wire heads of the braiding unit of the flow-blocking layer is n, where n≥1.

10. The knitted stent graft according to claim 9, characterized in that: The arrangement frequency of the interlayer connection structure in the circumferential direction of the bracket is a, 1≤a≤2m; The arrangement frequency of the interlayer connection structure in the axial direction of the stent is b, b=x*p, p is the braiding layer pitch, and x>0.

11. The knitted stent graft according to claim 1, characterized in that: The metal coverage of the support layer is in the range of 10 to 40%; The mesh size of the flow-blocking layer is in the range of 20 microns to 200 microns.

12. The knitted stent graft according to claim 3, characterized in that: A metal ring is provided between the braided unit of the support layer and the braided unit of the flow-blocking layer; The metal ring is a hollow tubular structure or a C-shaped tubular structure, and fixes the braided units of the support layer and the flow-blocking layer together at the interlayer connection structure.

13. The knitted stent graft according to claim 1, characterized in that: The cross-section of the braided unit includes but is not limited to special-shaped structures such as a circle, a triangle, and a hollow ring.

14. The knitted stent graft according to claim 1, characterized in that: The braided unit is made of a material with shape memory properties such as nickel titanium, cobalt chromium, or a DFT material containing a radiopaque component, or a shape memory material such as nickel titanium, cobalt chromium and a radiopaque material such as platinum tungsten or platinum iridium, etc., prepared separately or in combination.

15. The knitted stent graft according to claim 1, characterized in that: The outer diameter of the stent graft is in the range of 1.5 to 12 mm, and the length is in the range of 10 to 80 mm.

16. The knitted stent graft according to claim 1, characterized in that: When weaving starts or ends, the total number of threads w involved in weaving is evenly divided into n weaving thread groups, the number of threads in each weaving thread group is w / n, and n can be 3, 4, 6, 8, 10, or 12; The ε group is further divided into two bundles, ε is a natural number greater than 0, ε≤η; the two equally divided bundles rotate in the same direction or opposite directions to form a stable yarn bundle, and the two yarn bundles are bound together in parallel to form a closed yarn collection group.

17. The knitted stent graft according to claim 16, characterized in that: The end of the support layer is a partially closed structure, a fully closed structure or a loose structure; The end of the support layer can be formed into a partially closed or fully closed structure by winding, splitting and tailing, welding or bonding.

18. The knitted stent graft according to claim 1, characterized in that: The braided units of the support layer and the flow-blocking layer have a single wire diameter or a mixture of multiple wire diameters; The wire diameter of the braiding unit ranges from 0.0005 inches to 0.005 inches; The wire diameter of the braiding unit of the support layer is greater than or equal to the wire diameter of the braiding unit of the flow-blocking layer.

19. A method for preparing a knitted stent graft, used for preparing the stent graft according to any one of claims 1 to 18, characterized in that: The steps include: Using the weaving unit to weave the support layer through a weaving process; The flow-blocking layer is knitted along the outer surface of the support layer by a knitting process, and the knitting units are regularly interspersed in the support layer during the knitting process to obtain the flow-blocking layer and form a knitted stent graft with interlayer connection; The knitted stent graft is heat treated to be shaped.

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