Implantable stent and method of making same

Abstract

The invention provides an implantable stent and a manufacturing method thereof. A method of manufacturing an implantable stent formed by weaving a plurality of wires and each wire in the implantable stent having its respective final configuration, the method comprising: providing a plurality of wires, the plurality of wires comprising at least one first wire and at least one second wire, the first wire material is formed by a first material selected from materials with a shape memory function, and the second wire material is formed by a second material selected from materials with a degradable characteristic; performing pre-deformation and heat treatment on each of the plurality of wires to enable the wires to have a preset configuration; all the wires are mixed and woven to form the implantable stent, and according to the manufacturing method, heat treatment operation for heat setting is not carried out on the implantable stent formed through weaving.

Description

Technical Field

[0001] This application relates to an implantable stent, particularly a self-expanding stent, and a method for manufacturing the same. Background Technology

[0002] Vascular stents used as flow diverters (FDs) are typically formed from braided filaments. When a vascular stent is formed solely from shape memory alloy filaments, its long-term presence in the patient's body may cause chronic vascular inflammation and impair the recovery of vascular contractile function. When a vascular stent is formed solely from biodegradable material filaments, its stiffness and radial opening capacity may be insufficient. Therefore, in the art, a mixture of shape memory alloy filaments and biodegradable material filaments can be used to form stents.

[0003] However, during the heat treatment for shaping after the scaffold is woven, the shape memory alloy and biodegradable materials have different heat treatment conditions, such as a large difference in heat treatment temperature. As a result, the filaments of these two materials cannot simultaneously achieve the best shaping effect or their respective best mechanical properties, and thus cannot exert their maximum performance. Summary of the Invention

[0004] The purpose of this application is to solve at least one of the above-mentioned technical problems.

[0005] The first aspect of this application provides a novel method for manufacturing an implantable scaffold, comprising: an initial step of providing a plurality of filaments, the plurality of filaments including at least one first filament formed of a first material and at least one second filament formed of a second material, the first material being selected from materials with shape memory function and the second material being selected from materials with biodegradable properties; a shaping step of pre-deforming and shaping each of the plurality of filaments to a preset configuration; and a weaving step of mixing and weaving all the filaments to form the implantable scaffold.

[0006] In one embodiment, pre-deforming and heat-treating each filament to give it a predetermined configuration includes: Each first filament is pre-deformed and heat-treated to have a predetermined configuration, the shape of the predetermined configuration of the first filament being the same as the shape of its final configuration, and at least one dimension of the predetermined configuration of the first filament differing from the corresponding dimension of its final configuration; and Each second filament is pre-deformed and heat-treated to give it a preset configuration, the preset configuration of the second filament having the same shape and size as its final configuration.

[0007] In one embodiment, the preset and final configurations of each filament are helical, and the dimensions include the outer diameter and pitch of the helix.

[0008] In one embodiment, for the first filament, one of the outer diameter and pitch of the preset configuration is the same as the final configuration, and the other is larger than the final configuration.

[0009] In one embodiment, pre-deformation and heat treatment of each first filament includes determining the dimensions of the preset configuration based on the dimensions of the final configuration of the first filament before performing the pre-deformation operation.

[0010] In one embodiment, the plurality of filaments further includes at least one third filament formed of a third material, the third material being different from the first material and the second material, and the manufacturing method further includes: Before the mixed weaving, each third filament is pre-deformed and heat-treated to give it a preset configuration, which may be the same as or different from the final configuration.

[0011] A second aspect of this application provides a method for manufacturing an implantable stent, the implantable stent being formed by weaving together a plurality of filaments, each filament in the implantable stent having its own final configuration, the manufacturing method comprising the following steps: A plurality of filaments are provided, the plurality of filaments including at least one first filament and at least one second filament, the first filament being formed of a first material selected from materials having shape memory function, and the second filament being formed of a second material selected from materials having degradable properties; Each first filament is pre-deformed and heat-treated to shape it into the final configuration, the heat treatment being performed at a first heat treatment temperature specific to the first material; and All the filaments are mixed and woven together to form the implantable scaffold; The implantable stent is heat-treated at a second heat treatment temperature specific to the second material to shape it, the second heat treatment temperature being lower than the first heat treatment temperature.

[0012] In one embodiment, the plurality of filaments further includes at least one third filament formed of a third material, the third material being different from the first and second materials, wherein a third heat treatment temperature specific to the third material is higher than a second heat treatment temperature specific to the second material, and the manufacturing method further includes, prior to the mixed weaving: Before the mixed weaving, each third filament is pre-deformed and heat-treated at a heat treatment temperature specific to the third material to set it to its final configuration.

[0013] In one embodiment, the end of each filament is wound back and / or expanded.

[0014] In one embodiment, the mixed weaving includes winding some filaments clockwise and some filaments counterclockwise.

[0015] In one embodiment, the pre-deformation of the filament is performed by winding it onto a mandrel using a braiding machine, and the heat treatment is performed after the mandrel is removed.

[0016] In one embodiment, each of the plurality of filaments is in the form of a single filament or in the form of a strand composed of at least two filaments. Where the plurality of filaments include strand components, for each strand component, the step of providing a plurality of filaments includes the operation of forming the strand component by twisting and / or braiding at least two filaments.

[0017] This application also provides an implantable stent manufactured using the above method.

[0018] In one embodiment, each of the plurality of filaments is in the form of a single filament or in the form of a strand composed of at least two filaments. The single filament has a circular cross-section or a non-circular cross-section; The strand component is formed by twisting and / or braiding at least two filaments.

[0019] In one embodiment, the support includes a dense segment with low porosity and a sparse segment with high porosity.

[0020] In one embodiment, the implantable stent is a single-layer stent.

[0021] In one embodiment, the first filament is a single filament, at least one of the second filaments is a single filament, and at least another of the second filaments is a strand.

[0022] In one embodiment, the ratio of the number of the first filament, the number of individual filaments in the second filament, and the number of strands in the second filament is 1:8:3 or 1:3:2.

[0023] In one embodiment, the material with shape memory function includes nickel-titanium alloy and cobalt-chromium alloy; and / or, the material with degradable properties includes: magnesium-based, zinc-based, iron-based, or molybdenum-based degradable materials, polylactic acid, polyglycolic acid, polylactide, and polyglycolic acid.

[0024] In the manufacturing method of this application, each filament is pre-deformed and heat-set before being mixed and woven to form an implantable scaffold. Typically, the heat setting of each filament is achieved by performing a heat treatment specific to the filament material on the pre-deformed filament; that is, the heat treatment conditions for each filament depend on the forming material of that filament. In the heat setting step, all filaments are set to a preset configuration that is the same as or corresponds to the final configuration of the corresponding filament in the final implantable scaffold product during the mixed weaving step. The manufacturing method of this application does not include a setting operation or a heat treatment operation for setting purposes on the implantable scaffold product formed in the weaving step.

[0025] Using the manufacturing method of this application, the heat setting operation (or heat treatment operation) of each filament is performed separately based on its respective forming material, thereby giving each filament optimal setting effect, mechanical properties, and any other properties. Each filament with optimal setting effect and mechanical properties can automatically maintain its final configuration with optimal performance in all aspects within the final implantable scaffold product. Therefore, the implantable scaffold formed in the mixed weaving step no longer undergoes heat treatment for setting purposes, while each material and each filament possesses its own optimal setting effect and mechanical properties. The final configuration of the implantable scaffold product is not obtained by heat treating the entire implantable scaffold product containing different materials, but is ensured by the separate heat setting operation performed on each filament and each material in its respective heat setting step after pre-deformation operation. This fundamentally solves the technical problems in the prior art.

[0026] The implantable scaffold of this application is particularly advantageous when the heat treatment conditions for different materials forming the filament differ significantly (e.g., the heat treatment temperatures differ significantly). However, the principles of this application are obviously also applicable to situations where the heat treatment conditions for different materials are not significantly different.

[0027] Based on the principles described above in this application, each filament of the implantable scaffold can be a single filament or a strand formed by twisting and / or braiding at least two filaments. In the case of a strand, each filament forming the strand is made of the same material and therefore has the same heat treatment conditions for heat setting, but other parameters may differ, such as filament diameter and filament cross-sectional dimensions.

[0028] It is also conceivable that the implantable scaffold may include a third filament, a fourth filament, etc., which may be formed of the same material as the first material or the second material, or may be formed of other materials different from the first material and the second material. These other materials may, but do not necessarily, be selected from materials with shape memory function or materials with degradable properties.

[0029] This application also discloses an implantable scaffold, which is woven from at least one first filament, at least one second filament, and at least one third filament, and the final configuration of each filament in the implantable scaffold is directly woven. The first filament is a shape memory alloy filament having a preset configuration with the same shape as its final configuration but at least one dimension larger than its final configuration. The second filament is a biodegradable material filament having a preset configuration with the same shape and size as its final configuration. The third filament is a strand having a preset configuration with the same shape and size as its final configuration, and the strand is woven from at least two second filaments.

[0030] The implantable scaffold of this application is formed directly by weaving filaments with a preset configuration. Each filament has a preset configuration, that is, it has been pre-deformed and heat-set. Each filament already has the best shaping effect, mechanical properties and any other properties. Therefore, the woven scaffold does not need to be heat-treated or heat-set.

[0031] In one embodiment, the first filament is a single filament or a strand formed by multiple filaments, and the second filament is a single filament or a strand formed by multiple filaments.

[0032] In one embodiment, the filaments forming each filament have a circular or non-circular cross-section.

[0033] In one embodiment, the strand component is a braided component, a twisted component, or a braided twisted component.

[0034] In one embodiment, the first filament, the second filament, and the third filament are arranged at uniform intervals in the axial direction of the implantable stent.

[0035] In one embodiment, the implantable scaffold includes a dense segment with low porosity and a sparse segment with high porosity.

[0036] In one embodiment, the implantable stent includes two sparse segments located on opposite sides of a dense segment.

[0037] In one embodiment, the implantable stent is a single-layer stent.

[0038] In one embodiment, the ratio of the first filament, the second filament, or the third filament is 1:8:3 or 1:3:2.

[0039] In one embodiment, at least one dimension of the preset configuration of the first filament is larger than the corresponding dimension of the final configuration of the first filament.

[0040] In one embodiment, the preset and final configurations of each filament are helical, and the dimensions are one of the outer diameter and pitch of the helix.

[0041] In one embodiment, at least one of the first filament, the second filament, and the third filament has a winding portion and / or an expansion portion at its end. Attached Figure Description

[0042] Figure 1 This is an example of an implantable stent of this application.

[0043] Figure 2 yes Figure 1 A magnified view of region A, where an implantable stent can be placed.

[0044] Figure 3 and 4 These are two examples of stock components.

[0045] Figure 5 It is along Figure 2 A magnified view of a portion of region B.

[0046] Figure 6 It is along Figure 1 A cross-sectional view of the implantable stent P-P.

[0047] Figure 7 Similar to Figure 6 This shows an alternative embodiment of the implantable stent of Figure 1.

[0048] Figure 8 yes Figure 1 This is a diagram illustrating the implantable stent's position within the patient's body during use.

[0049] Figure 9 yes Figure 1 A schematic diagram of at least part of the biodegradable material of the implantable scaffold after degradation.

[0050] Figure 10 This is a flowchart of a method for manufacturing an implantable stent according to this application.

[0051] Figure 11 This illustrates the process of pre-winding a first filament onto a pre-wound mandrel according to the first embodiment.

[0052] Figure 12 This illustrates the process of mixing and weaving all the filaments on a braiding mandrel according to the first embodiment.

[0053] Figure 13 The support 100 is formed after the mixed weaving is completed and the braiding core is removed, according to the first embodiment.

[0054] Figure 14 This illustrates the process of pre-winding a first filament onto a pre-wound mandrel according to the second embodiment.

[0055] Figure 15 This illustrates the process of mixing and weaving all the filaments on a braiding mandrel according to the second embodiment.

[0056] Figure 16 The support 100 is formed after the mixed weaving is completed and the braiding core is removed, according to the second embodiment.

[0057] Figure 17 This refers to the situation where an expanded, rewinding portion is formed at the end of the wire during the prewinding process. Detailed Implementation

[0058] The implantable stent of this application is first described with reference to the examples in the accompanying drawings.

[0059] Figure 1 An exemplary tubular implantable stent 100 is shown, or a tubular portion thereof that can serve as an implantable stent. The stent 100 shown is a single-layer stent woven from a mixture of three filaments: a first filament 10, a second filament 20, and a third filament 30.

[0060] The first filament 10 is formed of a first material, which is selected from materials with shape memory function, such as shape memory alloys. The second filament 20 is formed of a second material different from the first material, which is selected from materials with degradable properties. The third filament 30 is formed of a third material, which can be selected from materials with shape memory function or materials with degradable properties. The third material can be the first material or the second material, or different from both. Examples of alloy materials with shape memory function in this application include nickel-titanium alloys (e.g., nickel-titanium alloys with or without developing materials), cobalt-chromium alloys (e.g., cobalt-chromium alloys with or without developing materials), or other shape memory alloy materials known in the art. The materials with degradable properties in this application can be, but are not limited to, metal-based degradable materials and polymeric degradable materials. Specifically, metal-based degradable materials can include, but are not limited to, magnesium-based, zinc-based, iron-based, molybdenum-based, and other degradable materials; polymeric degradable materials include, but are not limited to, polylactic acid, polyglycolic acid, polylactide, polyglycolic acid, etc. In the specific example illustrated, the third material forming the third filament 30 is the same as the second material.

[0061] In this application, the term "filament" refers to an elongated component whose extended length is significantly greater than its cross-sectional dimension (e.g., a length greater than 20, 30, 50, or more times any cross-sectional dimension). In this application, "filament" can refer to a single part, such as a single filament. Alternatively, "filament" can also refer to an assembly of multiple (e.g., two, three, or more) parts formed in any form, such as a strand of filaments combined in any way. Therefore, the term "filament" can refer to a (single) filament, a strand of filament, or any other similar substance.

[0062] In the illustrated example, the first filament 10 and the second filament 20 are single parts or single filaments, respectively; the third filament 30 in the illustrated example is a strand composed of multiple filaments, specifically a strand formed by two, three, or more filaments of biodegradable material. Preferably, the diameter (or outer diameter) of the first filament (i.e., shape memory alloy filament) 10 is larger than the diameter of the second filament (i.e., biodegradable material filament) 20 to provide better opening capability and rigidity. As an example, the diameter of the first filament 10 is in the range of 0.01~0.1 mm. The diameter of the second filament 20 can also be in the range of 0.01~0.1 mm.

[0063] When the "filament" is in the form of a strand, the strand can be formed by multiple filaments in a way that includes, but is not limited to, a weaving method that includes the crossing features between filaments, a twisting method that does not include the crossing features between filaments, or a combination of both. Figure 3 and 4 The examples shown are all formed by twisting the third filament 30, in which Figure 3 A first example of a third filament 30 in the form of a strand is shown, which is formed by twisting two filaments together; Figure 4 A second example of a third filament 30 in the form of a strand is shown, which is formed by twisting three filaments together. Although not shown in the figure, this application envisions embodiments in which the strand is formed of three or more filaments by cross-weaving at least some of the filaments, including a pure weaving method in which all the filaments are cross-weaved together, and a weaving-twisting combination method. An example of a weaving-twisting combination method is that the strand is formed of four filaments, where three filaments are cross-weaved and then twisted together with the fourth filament.

[0064] In this application, the "filament" constituting the "filament material" can be a conventional filament component with a circular cross-section, which can be represented by the "filament diameter" parameter; or it can be a component with a non-circular cross-section (e.g., oblong, square, or other polygonal, elliptical, etc.) and whose cross-sectional parameters are represented by at least two dimensions. That is, the first, second, or third "filament material" woven to form the support (whether in the form of a single filament, such as 10 or 20, or in the form of a strand component formed by multiple filaments, such as 30) may have a circular or non-circular cross-sectional outer contour, for example, it may be a flat "strip" in the conventional sense.

[0065] In the example shown in the accompanying drawings, the support 100 formed by the first filament 10, the second filament 20, and the third filament 30 is a single-layer support structure and is formed by winding on a mandrel of any desired configuration. Although the figures show that the support 100 has substantially uniform outer profile dimensions and pitch in the axial extension direction, this application is not limited thereto.

[0066] from Figure 1 As illustrated, the stent 100 comprises a dense segment 100a with a relatively dense weave and thus more turns per unit axial length (relatively low porosity), and sparse segments 100b and 100c located on opposite sides of the dense segment 100 with a relatively sparse weave and thus fewer turns per unit axial length (relatively high porosity). This can be achieved by adjusting the pitch of each wire 10, 20, and 30 in a correlated manner during the weaving process. When the stent 100 is used as an aneurysm occlusion stent, this locally (e.g., centrally) dense and otherwise (e.g., laterally) sparse stent can effectively occlude the aneurysm neck with the dense segment 100a while the sparse segments 100b and 100c do not obstruct important branches of the artery. However, depending on the patient's anatomy in the actual application, this application is not limited to the case where the dense segment 100a is located between the sparse segments 100b and 100c. Figure 8 is an illustration of the implantable stent of Figure 1 in use to block tumor T in a patient during use, and Figure 9 is an illustration of the degradation of at least part of the biodegradable material. Figure 8 and 9 The direction of blood flow is also indicated by arrows.

[0067] Figure 2 for Figure 1 A magnified view of a portion of region A. Figure 2 shows a complete winding turn of the first filament 10 (from 10a to 10b). From Figure 2 As can be seen, in this example, the support 100 is woven from 4 first filaments 10, 12 second filaments 20, and 8 third filaments 30. Of the 4 first filaments 10, 2 are clockwise wound (identified by 11 and 13 respectively, and a complete winding from 10a to 10b is a first filament 11), and 2 are counterclockwise wound (identified by 12 and 14 respectively); of the 12 second filaments 20, 6 are clockwise wound (identified by 21, 23, 25, 27, 29, and 31), and 6 are counterclockwise wound (identified by 22, 24, 26, 28, 32, and 34); of the 8 third filaments 30 in the form of strands, 4 are clockwise wound (identified by 33, 35, 37, and 39 respectively), and 4 are counterclockwise wound (identified by 36, 38, 42, and 44 respectively). Therefore, the ratio of the number of the first wire 10, the second wire 20 and the third wire 30 forming the support 100 shown in the figure is 4:12:8 or 1:3:2.

[0068] Figure 5 yes Figure 2 A magnified view of a portion of region B. Figure 6 For along Figure 1 The cross-sectional view of PP. Figure 7 Another example is shown where the ratio of the first filament 10, the second filament 20, and the third filament 30 is 3:8:1. It should be noted that the cross-sections of the filaments in the figure are not drawn to scale.

[0069] It is understood that this application does not limit the quantity, quantity relationship, or quantity ratio of the first filament 10, the second filament 20, and the third filament 30. The quantity or quantity ratio of the first filament 10, the second filament 20, and the third filament 30 can be determined based on the desired rigidity and compliance of the scaffold, the required support force, the expected value of the porosity after degradation of the biodegradable material, the diameter of each filament, and the characteristics of the biodegradable material, etc.

[0070] The above reference Figure 1-7 An exemplary structure of an implantable stent to which the principles of this application apply has been described. A method for manufacturing a stent according to this application is described below in conjunction with the aforementioned stent 100. Figure 10 A flowchart of the manufacturing method is shown.

[0071] This method begins with an initial step S1 of preparing the filaments 10, 20, and 30. Specifically, this step includes: preparing a suitable number of first filaments 10 of a first material, specifically preparing four shape memory alloy filaments with suitable diameters, for example, the diameter can be in the range of 0.01 to 0.1 mm; preparing a suitable number of second filaments 20 of a second material, specifically preparing twelve biodegradable material filaments with suitable diameters, for example, the diameter can also be in the range of 0.01 to 0.1 mm; and preparing a suitable number of third filaments 30 of a third material, specifically eight strands, each strand being formed by combining multiple, for example, at least two biodegradable material filaments (e.g., twisting and / or braiding).

[0072] Specifically, as in this example, when the filament includes strand components, this step may include the operation of forming strand components from multiple filaments by twisting and / or weaving.

[0073] Next, this method performs a first processing step S2 to pre-deform and heat-set each first filament 10 to its preset configuration, and a second processing step S3 to pre-deform and heat-set each second filament 20 and third filament 30 to their preset configurations. Heat setting is usually achieved through heat treatment, so "heat setting" and "heat treatment" can be used interchangeably in this document. In this document, "preset configuration" refers to the configuration of the pre-deformed filament and the configuration presented after heat setting, and "final configuration" refers to the configuration presented in the final support 100. Since the second filament 20 and the third filament 30 are formed of the same material, it can be understood that the heat setting or heat treatment conditions (mainly referring to the heat treatment temperature) for the second filament 20 are the same as those for the third filament 30.

[0074] Finally, this method performs a weaving step S4 in which all the filaments are mixed and woven to form the support 100. This weaving step S4 directly forms the support 100 product in which each filament is in its final configuration, and because heat setting operations were performed separately beforehand, each filament can automatically maintain its final configuration.

[0075] For each filament, the pre-deformation operation in step S2 or S3 can be exactly the same as the operation performed on that filament in the mixed weaving operation of step S4. Figure 1-7 Taking the cylindrical braided structure support 100 as an example, in step S2 or S3, the pre-deformation of any wire can be achieved by winding it onto a mandrel using a braiding machine, while heat setting can be achieved by removing the mandrel first and then performing heat treatment. In braiding step S4, the mixing and weaving of all the core wires can also be achieved using a mandrel on a braiding machine. The advantage of using a braiding machine is that it eliminates the need for a special threading bar, allowing for direct weaving of spirals at the required pitch, which is adjustable and more stable than hand winding.

[0076] Specifically, for the first filament 10 of the shape memory alloy material, the heat treatment for heat setting is performed at a first higher temperature specific to the specific shape memory alloy material; for the second filament 20 and the third filament 30 of the biodegradable material, the heat treatment for heat setting is performed at a second lower temperature specific to the specific biodegradable material. Therefore, the heat treatment or heat setting operation of each filament is performed at a heat treatment temperature specific to its respective material, and each filament can obtain its own optimal setting effect and optimal mechanical properties.

[0077] This method eliminates the need for heat treatment for heat setting of the support 100 formed in programming step S4. This is particularly advantageous for supports woven from filaments of multiple materials. It solves the technical problem that when heat treatment or heat setting is performed on the entire support (or all filaments of various materials simultaneously) after weaving filaments of multiple materials into a support, the filaments of different materials cannot simultaneously achieve the best setting effect or the best mechanical properties.

[0078] In the first embodiment, the preset configuration of all filaments after pre-deformation and heat setting is exactly the same as the final configuration of the filament in the final support, that is, the shape and size are exactly the same. In this embodiment, since the preset configuration of all filaments is the same as the final configuration, the mandrel used for pre-deformation or pre-winding of any filament (sometimes referred to herein as a "pre-winding mandrel") can be the same as the mandrel used in the final mixed weaving step S4 (sometimes referred to herein as a "weaving mandrel"), that is, it can have the same outer diameter.

[0079] The second implementation considers the influence of the interaction between different filaments in the mixed weaving step S4 on the final configuration. The preset configuration of the shape memory alloy filament (i.e., the first filament 10) can be designed so that its shape is the same as the final configuration, but at least one dimension differs from the final configuration. For the helical support, the dimensions are the outer contour dimension (i.e., outer diameter) and the pitch; at least one of the outer diameter and pitch in the preset configuration of the first filament 10 can be slightly larger than the corresponding dimension in the final configuration. Simultaneously, the preset configuration of the filaments of the biodegradable material (i.e., the second filaments 20 and 30) can be designed so that its shape and all dimensions are the same as the final configuration. The advantage of this implementation is that in the mixed weaving step S4, the first filament 10, which has greater rigidity, is bound by the second filament 20 and the third filament 30, which are made of other biodegradable materials, and its size can be slightly reduced to the size of the final configuration. At the same time, the size of the second filament 20 and the third filament 30, which are made of other biodegradable materials with relatively less rigidity, is maintained by the support of the first filament 10, so that all filaments can obtain their final configuration and the entire support product has the desired configuration.

[0080] In this second embodiment, the method further includes step S15 before step S2, which involves determining the size of a preset configuration based on the final configuration (size) of the first filament 10. For the spiral support, this step involves determining the outer diameter and pitch of the preset configuration based on the outer diameter and pitch of the final configuration.

[0081] The desired outer diameter and pitch of the final configuration of the first filament 10 are denoted by D and S, respectively. The outer diameter D (“final outer diameter”) and pitch S (“final pitch”) of the final configuration are both known expected values ​​based on the actual application (e.g., the anatomical structure of the patient to be applied). In step S2, the outer diameter and pitch of the preset configuration obtained by pre-deforming and heat-setting the first filament 10 are denoted by D1 (“preset outer diameter” or “pre-wound outer diameter”) and S1 (“preset pitch” or “pre-wound pitch”), respectively. It can be understood that the outer diameter of the pre-wound mandrel 85 corresponds to the outer diameter D1, for example, by subtracting the diameter of the first filament 10 from the outer diameter D1. In step S4, the outer diameter and pitch of the first filament 10 used during the mixed weaving process are denoted by D2 (“weaving outer diameter”) and S2 (“weaving pitch”), respectively. The outer diameter of the weaving mandrel 95 corresponds to the outer diameter D2. Below are two methods and examples for determining the outer diameter D1 and pitch S1, and the outer diameter D2 and pitch S2 based on the outer diameter D and pitch S, respectively.

[0082] Example 1: Let D1=D, S1=S2, and select D2 as a predetermined value less than D1 (for example, the difference between the two is in the range of 0.5-2.0 mm), then the pitch S1 can be calculated by formula (1): (1).

[0083] Next, in step S2, each first filament 10 is pre-wound and heat-set using a pre-wound mandrel 85 corresponding to the outer diameter D1 (=D) based on parameters D1 (=D) and S1 (as calculated above), resulting in a preset configuration with an outer diameter D1 and pitch S1. In the final mixed weaving step S4, the first filament 10 is mixed-woven with any other material and the second and third filaments that have already undergone step S3, using a weaving mandrel 95 corresponding to the outer diameter D2 (as selected above). After weaving is complete, removing the weaving mandrel 95 yields the desired support 100, wherein the first filament 10 exhibits a final configuration with the desired outer diameter D and pitch S, and the other filaments have the same final configuration as the preset configuration.

[0084] Figure 11-13 This example is shown. Figure 11 The illustration shows a preset configuration in which the first wire diameter 10 is pre-wound on the pre-wound mandrel 85, having an outer diameter D1 and a pitch S1; Figure 12 The illustration shows the process of simultaneously weaving a first filament diameter 10 with other filaments on a braiding mandrel 95, wherein the first filament diameter 10 has an outer diameter D2 and a pitch S2. Figure 13 From Figure 12 After removing the braided mandrel 95, the support 100 product has a first wire diameter 10 with a desired outer diameter D and pitch S, wherein the dimensional relationships satisfy: D1=D>D2, S1=S2>S.

[0085] Example 2: Let S1 = S, D1 = D2, and select S2 as a predetermined value greater than S1 (for example, the difference between the two is in the range of 0.1-1.5 mm), then the outer diameter D1 can be calculated by formula (2): (2).

[0086] Next, in step S2, each first filament 10 is pre-wound using a pre-wound mandrel 85 corresponding to the outer diameter D1 (as calculated above) based on parameters D1 and S1 (=S) and then heat-set to obtain a preset configuration with an outer diameter D1 and pitch S1. In the final mixed weaving step S4, the first filament 10 is mixed-woven with the second and third filaments of any other material that have already undergone step S3 using a weaving mandrel 95 corresponding to the outer diameter D2 (=D1) and parameters D2 and S2 (selected predetermined values). After weaving is completed, removing the weaving mandrel 95 yields the desired support 100, wherein the first filament 10 presents a final configuration with the desired outer diameter D and pitch S, and the other filaments have the same final configuration as the preset configuration.

[0087] Figure 14-16 This example is shown. Figure 14 The illustration shows a preset configuration with a first wire diameter 10 pre-wound on a pre-wound mandrel 85, having an outer diameter D1 and a pitch S1; Figure 15 The illustration shows the process of mixing and weaving the first filament diameter 10 with other filaments on the braiding mandrel 95. The parameters used for the first filament diameter 10 in this process are the outer diameter D2 and the pitch S2. Figure 16 From Figure 12 The support 100 product after removing the braided mandrel 95 has a first wire diameter 10 with a desired outer diameter D and pitch S. The dimensional relationships satisfy: D1=D2>D, S1=S <S2。

[0088] The above describes, with two examples, a method for determining the preset configuration (D1 and S1) of the first filament 10 based on its final configuration (D and S), and the parameters (D2 and S2) applied to the first filament during the mixed weaving process. It also explains how to select the preset mandrel 85 and the weaving mandrel 95 used. By employing the second embodiment, making the preset configuration of the first filament different from its final configuration, the technical effect of further improving the stability and the opening capability of the support during the mixed weaving process can be achieved.

[0089] Optionally, but not necessarily, this manufacturing method may perform a heat treatment operation on the entire support 100 after weaving to form the final support 100, for the purpose of releasing internal stress. The heat treatment temperature for this operation can be selected without impairing the heat setting effect and mechanical properties of the individual filaments. As an example, the heat treatment temperature for this operation may be equal to or lower than a second lower temperature. This allows for at least partial elimination of the interaction stress between the individual filaments during the mixed weaving operation.

[0090] In some embodiments, in the pre-deformation and heat-setting process steps S2 or S3, one or both ends of the preset configuration of any or all the filaments can be designed with bends. The purpose is to avoid the ends of the filaments interfering with each other in the mixed weaving operation S4, and also to prevent the ends of the filaments of the stent 100 from extending haphazardly and causing damage to blood vessels during use. Figure 17 The diagram shows the pre-winding of filament onto a pre-winding mandrel 85. A back-wound portion 98, specifically an expanded form as shown, is formed at one end (the left end in the diagram). "Back-wound" refers to the curved end formed when the same filament is folded in half; compared to a relatively sharp filament end, the back-wound portion has a smooth outer contour. "Expansion" refers to a tapered enlargement whose outer diameter gradually increases in the axial direction towards the end. Although... Figure 17The right end is not shown, but it is conceivable that the right end of the preset configuration may also include features such as an expansion portion. Those skilled in the art will understand that it is also possible to design only a wrap-around feature and only an expansion feature at the end, the size of which is typically a few millimeters, without any adverse effects.

[0091] The above description, with reference to two embodiments, details an exemplary manufacturing method of the stent 100 of this application. The following describes another or a second exemplary manufacturing method based on the principles of this application.

[0092] The other manufacturing method may include: the same initial steps as described above for preparing each filament; a process step of pre-deforming and heat-setting each first filament 10 to its preset configuration; a process step of mixing each first filament in the preset configuration with all (unpre-deformed and heat-set) second filaments 20 and third filaments 30 to weave a support 100; and a process step of heat-setting the woven support at a heat treatment temperature of a biodegradable material specific to the second filaments 20 and third filaments 30.

[0093] In this manufacturing method, the heat treatment operation after pre-deformation of the first wire is carried out under heat treatment conditions or temperatures specific to the first wire and alloy material, so that all shape memory alloy wires achieve their best shaping effect and best mechanical properties.

[0094] This method does not involve pre-deformation and heat setting of the second and third filaments, which have lower heat treatment temperatures. Instead, the heat setting of the entire framework after weaving is performed at a heat treatment temperature specific to the biodegradable material, which is lower than the heat treatment temperature of the first filament. This allows the second and third filaments to achieve optimal shaping and mechanical properties without compromising the optimal shaping and mechanical properties of the first filament.

[0095] This second exemplary manufacturing method can also solve the technical problem that all filaments cannot simultaneously achieve optimal shaping effect and optimal mechanical properties. In this embodiment, the preset configuration of the first filament can be completely identical to the final configuration in terms of shape and size.

[0096] Two exemplary manufacturing methods based on the principles of this application have been described above. Those skilled in the art will understand that this application is not limited to the foregoing description, and many modifications and variations can be conceived after reading the foregoing description, such as some of the exemplary variations below.

[0097] Although the foregoing description describes the support 100 as containing filaments of two materials, this application is clearly applicable to situations where the support 100 is woven from a mixture of filaments of more materials. The more types of materials the support contains and the greater the difference in heat treatment conditions for the materials, the more obvious the superiority of the method of this application becomes. In particular, for the second exemplary manufacturing method described above, if the filaments forming the support 10 involve three or more materials, and the heat treatment temperature (for heat setting purposes) corresponding to all materials is higher than the heat treatment temperature for stress relief of the finished support, then, except for the filaments made of the material with the lowest (for heat setting purposes) heat treatment temperature, all other filaments need to undergo pre-forming and heat setting heat treatment before being mixed and woven. For example, if the aforementioned third filament 30 is formed of another material that is different from both the first and second filaments, or if the support 100 also includes a fourth filament formed of the other material in addition to the first, second, and third filaments, and the heat treatment temperature (for heat setting purposes) corresponding to the other material is between the heat treatment temperatures (for heat setting purposes) corresponding to the materials corresponding to the first filament 10 and the second filament 20, then the second exemplary manufacturing method further includes: pre-shaping and heat setting all the filaments of the other material before the mixed weaving operation.

[0098] Although in the foregoing description, the three filaments 10, 20, and 30 forming the support 100 are respectively a single filament of shape memory alloy material, a single filament of biodegradable material, and a strand of biodegradable material, this application does not limit the form of any of the filaments 10, 20, and 30. That is, any one of the first filament 10, the second filament 20, and the third filament 30 can be in the form of a single filament or a strand. For example, the first filament 10, the second filament 20, and the third filament 30 may be respectively: a first strand of shape memory alloy material, a second strand of biodegradable material, and a third strand of biodegradable material. For example, the second strand and the third strand may differ in at least one aspect such as specific material, filament diameter, number of filaments, and combination form (braiding and / or twisting).

[0099] Although the bracket 100 is described above as being woven from a mixture of three filaments 10, 20, and 30, this application also applies to cases where it is woven from two or more filaments.

[0100] Although the stent 100 is described above as being formed from filaments of two different materials, this application also applies to stents woven from filaments of three or more materials.

[0101] Although the foregoing description describes the support 100 as being formed by spirally winding the filaments around a mandrel, this application is not limited thereto. That is, the support does not necessarily have to be formed by "regular" spiral winding or by winding with a mandrel. This application applies to situations where a support is formed by deforming filaments of at least two different materials through any means of binding the filaments together.

[0102] As mentioned above, the pre-deformation of each filament does not necessarily have to be the same as the deformation process during the mixing and winding of the filaments; it is sufficient that each filament is shaped to its preset configuration.

[0103] As mentioned above, this application is particularly advantageous when the shaping conditions (or heat treatment conditions for heat shaping) of various materials forming the support are different or even significantly different, but this application is not limited to situations where different materials require different heat treatment conditions. Heat treatment conditions can be reflected in the heat treatment method (e.g., the apparatus used), the temperature reached, the treatment time, etc.

[0104] The principles of this application have been described above with reference to the accompanying drawings. The foregoing disclosure is not intended to be exhaustive or to limit this application to any particular form. The terminology used is intended to be descriptive rather than restrictive. Many modifications and variations can be made based on the foregoing teachings, and the invention can be practiced in ways different from the specific descriptions.

Claims

1. A method for manufacturing an implantable stent, the implantable stent being formed by weaving together a plurality of filaments and each filament in the implantable stent having its own final configuration, the manufacturing method comprising: A plurality of filaments are provided, the plurality of filaments including at least one first filament and at least one second filament, the first filament being formed of a first material selected from materials having shape memory function, and the second filament being formed of a second material selected from materials having degradable properties; Each of the plurality of filaments is pre-deformed and heat-treated to give it a predetermined configuration; and All the filaments are mixed and woven together to form the implantable scaffold. The manufacturing method does not perform heat treatment for heat setting on the implantable scaffold formed by the braid.

2. The manufacturing method according to claim 1, wherein, Each filament undergoes pre-deformation and heat treatment to achieve a predetermined configuration, including: Each first filament is pre-deformed and heat-treated to have a predetermined configuration, the shape of the predetermined configuration of the first filament being the same as the shape of its final configuration, and at least one dimension of the predetermined configuration of the first filament differing from the corresponding dimension of its final configuration; and Each second filament is pre-deformed and heat-treated to give it a preset configuration, the preset configuration of the second filament having the same shape and size as its final configuration.

3. The manufacturing method according to claim 2, wherein, The preset and final configurations of each filament are helical, and the dimensions include the outer diameter and pitch of the helix.

4. The manufacturing method according to claim 3, wherein, For the first filament, one of the outer diameter and pitch of the preset configuration is the same as the final configuration, and the other is larger than the final configuration.

5. The manufacturing method according to claim 4, wherein, Pre-deformation and heat treatment of each first filament includes determining the dimensions of the preset configuration based on the dimensions of the final configuration of the first filament before performing the pre-deformation operation.

6. The manufacturing method according to any one of claims 1-5, wherein, The plurality of filaments further includes at least one third filament, the third filament being formed of a third material, the third material being a third material different from the first material and the second material, and the manufacturing method further includes: Before the mixed weaving, each third filament is pre-deformed and heat-treated to give it a preset configuration, which may be the same as or different from the final configuration.

7. A method for manufacturing an implantable stent, the implantable stent being formed by weaving together a plurality of filaments and each filament in the implantable stent having its own final configuration, the manufacturing method comprising the following steps: A plurality of filaments are provided, the plurality of filaments including at least one first filament and at least one second filament, the first filament being formed of a first material selected from materials having shape memory function, and the second filament being formed of a second material selected from materials having degradable properties; Each first filament is pre-deformed and heat-treated to shape it into the final configuration, the heat treatment being performed at a first heat treatment temperature specific to the first material; and All the filaments are mixed and woven together to form the implantable scaffold; The implantable stent is heat-treated at a second heat treatment temperature specific to the second material to shape it, the second heat treatment temperature being lower than the first heat treatment temperature.

8. The manufacturing method according to claim 7, wherein, The plurality of filaments further includes at least one third filament formed of a third material, which is different from the first and second materials, wherein a third heat treatment temperature specific to the third material is higher than a second heat treatment temperature specific to the second material, and the manufacturing method further includes, prior to the mixed weaving: Before the mixed weaving, each third filament is pre-deformed and heat-treated at a heat treatment temperature specific to the third material to set it to its final configuration.

9. The manufacturing method according to any one of claims 1-8, wherein, Wrap and / or expand the end of each wire.

10. The manufacturing method according to any one of claims 1-9, wherein, Mixed weaving involves winding some yarns clockwise and some yarns counterclockwise.

11. The manufacturing method according to any one of claims 1-10, wherein, The filament is pre-deformed by winding it around a mandrel using a braiding machine, and the heat treatment is performed after the mandrel is removed.

12. The manufacturing method according to any one of claims 1-11, wherein, Each of the plurality of filaments is either a single filament or a strand composed of at least two filaments. Where the plurality of filaments include strand components, for each strand component, the step of providing a plurality of filaments includes the operation of forming the strand component by twisting and / or braiding at least two filaments.

13. An implantable stent manufactured by the manufacturing method according to any one of claims 1-12.

14. The implantable stent according to claim 13, wherein, Each of the plurality of filaments is either a single filament or a strand composed of at least two filaments. The single filament has a circular cross-section or a non-circular cross-section; The strand component is formed by twisting and / or braiding at least two filaments.

15. The implantable stent according to claim 13 or 14, wherein, The support includes a dense section with low porosity and a sparse section with high porosity.

16. The implantable stent according to any one of claims 13-15, wherein, The implantable stent is a single-layer stent.

17. The manufacturing method according to any one of claims 13-16, wherein, The first filament is a single filament, at least one of the second filaments is a single filament, and at least another of the second filaments is a strand.

18. The manufacturing method according to claim 17, wherein, The ratio of the number of the first filament, the number of individual filaments in the second filament, and the number of strands in the second filament is 1:8:3 or 1:3:

2.

19. The implantable stent according to any one of claims 13-18, wherein, The materials with shape memory function include nickel-titanium alloys and cobalt-chromium alloys; and / or, the materials with degradable properties include: magnesium-based, zinc-based, iron-based, or molybdenum-based degradable materials, polylactic acid, polyglycolic acid, polylactide, and polyglycolic acid.

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