Guide wire and its manufacturing method

Abstract

[Problem] To provide a guidewire and a method for manufacturing the guidewire, which maintains high operability and vascular selectivity by having shape-forming properties that allow it to be shaped into a desired form and shape retention properties that maintain the shape when shaped relative to external forces applied within the blood vessel, thereby simplifying surgical procedures. [Solution] The guidewire 100 includes a core component 10 with a long strip having a flat portion 11g at its tip. The flat portion 11g is made of a material with an elastic deformation power of 46.0% to 59.5% and a Martens hardness of 1300 N / mm². 2 Above 3000N / mm 2 Below, a martensitic hardness of 1300 N / mm is preferred. 2 The above is 2120 N / mm 2 The following Ni-Ti alloy is formed.

Description

Technical Field

[0001] This invention relates to guidewires and methods for manufacturing guidewires. Background Technology

[0002] A guidewire is a medical device used to guide various catheters to the narrowed areas of blood vessels such as the coronary arteries for treatment.

[0003] Guidewires need to navigate the complex bends and branches of blood vessels and pass through narrow sections. Therefore, the tip of the guidewire requires flexibility, resilience to external forces, and kink resistance. To meet these requirements, the tip of the guidewire is formed from a superelastic alloy such as Ni-Ti alloy.

[0004] However, before inserting the guidewire into a blood vessel, the operator sometimes shapes the tip of the guidewire to improve its maneuverability within the vessel and the selectivity of the branching vessels. Therefore, it is preferable that the tip of the guidewire can be easily shaped. However, for guidewires with tips made of hyperelastic alloys, if the hyperelasticity is high, even if the operator applies external force to shape it, it will return to its original shape when the external force is removed, making it difficult for the operator to achieve the desired shape.

[0005] The following patent document 1 discloses the following technology: by cold working and heat treating the front end of the guide wire formed of a superelastic alloy, the superelasticity is reduced, making it possible to form the front end of the guide wire.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Publication No. 2002-503529 Summary of the Invention

[0009] The problem that the invention aims to solve

[0010] However, if the hyperelasticity of the guidewire tip is too low, its shape is difficult to restore, thus reducing shape retention, a property essential for maintaining the shape during shaping. When a guidewire is inserted into a blood vessel, it is subjected to external force by its tip contacting the vessel wall or narrowing. At this point, the guidewire, with excessively reduced hyperelasticity at the tip, undergoes plastic deformation into a shape different from its initial shape. This reduces the guidewire's operability and vessel selectivity. If plastic deformation occurs at the tip of the guidewire during endovascular manipulation, the operator must remove the guidewire from the vessel, reshape it, or replace it with another guidewire, making the procedure more complex. This prolongs the procedure time and increases the burden on both the operator and the patient.

[0011] The external force exerted on the guidewire within the blood vessel is less than the force applied by the operator for shaping. Therefore, the tip of the guidewire needs to possess the following properties: it should be deformable under the larger force applied by the operator for shaping, but should not undergo plastic deformation under the smaller force applied during the procedure and should be able to return to its original shape. In other words, the tip of the guidewire needs to possess both the shape-forming ability to be shaped into the desired shape before insertion into the blood vessel and the shape-retention ability to maintain its original shape relative to the external force applied within the blood vessel.

[0012] At least one embodiment of the present invention was made in view of the above circumstances, specifically providing a guidewire and a method of manufacturing the guidewire, which has shape-forming properties capable of being shaped into a desired shape and shape retention properties when the shape is maintained relative to an external force applied within a blood vessel.

[0013] Methods for solving problems

[0014] The guidewire according to this embodiment includes a long strip core component with a flat section at its front end. The flat section is made of material with an elastic deformation power of 46.0% to 59.5% and a Martens hardness of 1300 N / mm². 2 Above 3000N / mm 2 The following Ni-Ti alloy is formed.

[0015] The guidewire manufacturing method disclosed in this embodiment is a method for manufacturing a guidewire having a core component. This manufacturing method includes: a step of cold-working the front end of the core component, which has a flat portion and a transition portion extending from the base end of the flat portion along the long axis towards the base end; and a step of having an elastic deformation power of 46.0% to 59.5% and a Martens hardness of 1300 N / mm². 2 Above 3000N / mm 2 The following is a process of heat-treating at least a portion of the aforementioned flat plate portion and the aforementioned transition portion.

[0016] The effects of the invention

[0017] According to one embodiment of the present invention, a guidewire can be provided that, by controlling the elastic deformation power and martensitic hardness of the tip of the guidewire formed of a Ni-Ti alloy within a specified range, possesses the physical property of being deformable under a large force applied by the operator for shaping, but not plastically deformed under a small force applied during surgical operation, and thus able to return to its original shape. That is, according to one embodiment of the present invention, a guidewire possessing both shaping and shape retention properties can be provided. Thus, the guidewire can be shaped by the operator, and even when subjected to an external force that deforms the tip within the blood vessel, it can return to its original shape. Therefore, the guidewire can maintain the high operability and vascular selectivity imparted by shaping during surgery. Furthermore, the operator does not need to remove the guidewire from the blood vessel for reshaping or replacement with another guidewire, thus simplifying the procedure. This shortens the surgical time, thereby reducing the burden on both the operator and the patient. Attached Figure Description

[0018] [ Figure 1 [This is a schematic top view of the guidewire involved in this embodiment.]

[0019] [ Figure 2 This is a partial cross-sectional view along the long axis of the guidewire involved in this embodiment, viewed from the thickness direction.

[0020] [ Figure 3A [This is a schematic perspective view of the front end of the first core of the guidewire according to this embodiment.]

[0021] [ Figure 3B [This is a schematic top view of the front end of the first core of the guidewire according to this embodiment.]

[0022] [ Figure 4A This is a conceptual diagram illustrating the rigid state of the first core of the guidewire according to this embodiment before heat treatment.

[0023] [ Figure 4B [A conceptual diagram illustrating the rigidity of the first core of the guidewire according to this embodiment when only a portion of the flat plate is heat-treated.]

[0024] [ Figure 4C [A conceptual diagram illustrating the rigid state of the first core of the guidewire according to this embodiment when heat treatment is applied to a portion of the transition in addition to the flat plate portion.]

[0025] [ Figure 5A This is a schematic diagram of the branching model used in the prolapse resistance test.

[0026] [ Figure 5B [This is a diagram illustrating the shaping of the tip of the guidewire.]

[0027] [ Figure 6 This is a schematic diagram of the narrow model used in the kink resistance test.

[0028] [ Figure 7 This is a diagram used to illustrate the bending height in the kink resistance test. Detailed Implementation

[0029] Hereinafter, the methods for implementing the present invention will be described in detail with reference to the accompanying drawings. The embodiments shown herein are illustrative examples for embodying the technical concept of the present invention and do not limit the present invention. Furthermore, all other implementable methods, embodiments, and techniques that can be conceived by those skilled in the art without departing from the spirit of the present invention are included within the scope and spirit of the present invention, and are included within the scope of the invention and its equivalents as described in the claims.

[0030] Furthermore, for the purpose of illustration and understanding, the accompanying drawings added to this specification are sometimes schematic representations of actual objects with appropriate scales, aspect ratios, shapes, etc., but these are merely examples and do not limit the interpretation of the present invention.

[0031] For ease of explanation, the direction of the guidewire 100 in its natural state (extending straight without any external force) is defined in this manual. Figure 1 In this context, "major axis direction" refers to the direction in which the guidewire 100 extends, defined as the direction along the central axis C of the guidewire 100 (the left-right direction in the figure). "Radial" refers to the direction relative to the core in an axially orthogonal section (cross-section) of the core with the major axis direction of the guidewire 100 as the reference axis, moving away from or towards the core. "Circumferential" refers to the direction of rotation with the major axis direction of the core as the reference axis. "Thickness direction" refers to the direction in which the short side of the rectangle in the transverse sectional view of the plate portion 11g extends when the guidewire 100 has a plate portion 11g at its front end (the near-forward / depth direction in the figure). "Width direction" refers to the direction in which the long side of the rectangle in the transverse sectional view of the plate portion 11g extends when the guidewire 100 has a plate portion 11g at its front end (the up-down direction in the figure).

[0032] Furthermore, the side where the guidewire 100 is inserted into the blood vessel is designated as the "front end side," and the side opposite to the front end side (the side held by the operator) is designated as the "base end side." Additionally, the portion including a constant range along the long axis from the front end (the most front end) is designated as the "front end portion," and the portion including a constant range along the long axis from the base end (the most base end) is designated as the "base end portion."

[0033] It should be noted that in the following descriptions, the use of ordinal numbers such as "the first" and "the second" is for convenience only, unless otherwise specified, and no order is prescribed.

[0034] The guidewire 100 described in this embodiment is a medical device inserted into a blood vessel to guide a catheter or stent used for endovascular treatment to a narrowed portion. It should be noted that the guidewire 100 can also be used to insert into other biological cavities (blood vessels, urinary catheters, bile ducts, fallopian tubes, hepatic ducts, etc.) depending on the treatment purpose.

[0035] [constitute]

[0036] like Figure 1 or Figure 2 As shown, the guidewire 100 according to this embodiment has a long core component 10, a lumen 20 covering the periphery of the front end of the core component 10, a fixing part 30 for fixing the lumen 20 to the core component 10, and a coating layer 40 covering each component including the core component 10. Hereinafter, each part of the guidewire 100 will be described in detail.

[0037] <Core Components>

[0038] The core component 10 includes a first core 11 and a second core 12 disposed on the base end side of the first core 11 and joined to the first core 11.

[0039] The first core 11 is a long strip extending from the front end of the second core 12 to the front end of the guide wire 100 along its long axis. The first core 11 includes, from its base end to its front end, a first joint 11a, a first outer diameter constant 11b, a first tapered 11c, a second outer diameter constant 11d, a second tapered 11e, a transition 11f, and a flat plate 11g, all of which are integrally formed.

[0040] The first joint 11a is the part that joins with the second joint 12b of the second core 12, which will be described later. The outer diameter of the first joint 11a is larger than the outer diameter of the first outer diameter constant portion 11b, and approximately equal to the outer diameter of the second joint 12b. The outer diameters of the first joint 11a and the second joint 12b are larger than the outer diameters of the first outer diameter constant portion 11b and the base 12a of the second core 12. That is, the area of ​​the joint surface 13 of the first joint 11a and the second joint 12b is larger than that of the first outer diameter constant portion 11b and the base 12a. As a result, when the guide wire 100 bends, the stress acting on the joint surface 13 is dispersed to the first outer diameter constant portion 11b and the base 12a, whose outer diameters are smaller than those of the joint surface 13, thus suppressing stress concentration on the joint surface 13. Therefore, the core component 10 can achieve high bonding strength at the joint surface 13.

[0041] The first outer diameter constant portion 11b extends a predetermined length from the front end of the first joint portion 11a to the base end of the first tapered portion 11c. The outer diameter of the first outer diameter constant portion 11b is approximately constant and is approximately equal to the outer diameter of the base portion 12a of the second core portion 12.

[0042] The first tapered portion 11c extends a predetermined length from the front end of the first constant outer diameter portion 11b to the base end of the second constant outer diameter portion 11d. The first tapered portion 11c is formed into a tapered shape in which the outer diameter gradually decreases from the first constant outer diameter portion 11b towards the front end. The tapered shape of the first tapered portion 11c can be formed by mechanically grinding the first core portion 11 with a grinding stone or etching it with acid.

[0043] The second outer diameter constant portion 11d extends a predetermined length from the front end of the first cone portion 11c to the base end of the second cone portion 11e. The outer diameter of the second outer diameter constant portion 11d is approximately constant and smaller than the outer diameter of the first outer diameter constant portion 11b.

[0044] The second tapered portion 11e extends a predetermined length from the front end of the second outer diameter constant portion 11d to the base end of the transition portion 11f. The second tapered portion 11e is formed into a tapered shape in which the outer diameter gradually decreases from the second outer diameter constant portion 11d to the transition portion 11f. The tapered shape of the second tapered portion 11e can be formed by mechanically grinding the first core portion 11 with a grinding stone or etching it with acid.

[0045] The transition portion 11f extends a predetermined length from the front end of the second tapered portion 11e to the base end of the flat plate portion 11g. For example... Figure 3A or Figure 3B As shown, the transition portion 11f is formed into a wedge shape, with its thickness gradually decreasing from the second conical portion 11e to the flat plate portion 11g and its width gradually increasing. The wedge shape of the transition portion 11f can be formed by a cold working process, namely stamping, on the first core portion 11, which has a circular cross-sectional shape. In a plan view (transverse sectional view) orthogonal to the major axis, the cross-sectional shape of the transition portion 11f forms a circle with an outer diameter approximately equal to that of the second conical portion 11e at the base end, but gradually deforms from a circle to a rectangle from the base end to the front end, forming a rectangle with a shape approximately the same as that of the flat plate portion 11g at the front end. The front end of the transition portion 11f has a thickness and width approximately equal to that of the base end of the flat plate portion 11g, forming a surface continuous with the flat plate portion 11g. It should be noted that... Figure 3B The double-dotted line in the figure is an imaginary line dividing the area of ​​the flat plate portion 11g, the transition portion 11f, and the second cone portion 11e. In addition, the "thickness" of the flat plate portion 11g is set to the length of the short side of the rectangle in the cross-sectional view of the flat plate portion 11g, and the "width" of the flat plate portion 11g is set to the length of the long side of the rectangle in the cross-sectional view of the flat plate portion 11g.

[0046] The flat plate portion 11g extends a predetermined length from the front end of the transition portion 11f to the front end of the guide wire 100. The flat plate portion 11g is formed by stamping a first core portion 11 having a circular cross-sectional shape. Therefore, the cross-sectional shape of the flat plate portion 11g is rectangular. The thickness of the flat plate portion 11g is approximately constant from the front end of the transition portion 11f to the front end of the flat plate portion 11g. Figure 3A and Figure 3B As shown, the shape of the plate portion 11g, viewed from the thickness direction, is formed as a rectangle with rounded corners at the front end. Therefore, the width of the plate portion 11g is approximately constant from the front end of the transition portion 11f towards the front end, but decreases in the portion with rounded corners. It should be noted that the width of the plate portion 11g may also be constant from the front end of the transition portion 11f to the front end of the plate portion 11g. The cross-sectional shape of the plate portion 11g is limited to a rectangle, but it may also be a rounded rectangle with an R-shape at the corners.

[0047] It should be noted that the structure of the first core 11 is not limited to the structure described above. For example, the first core 11 may also have a constant shape and a constant outer diameter from the front end to the base end.

[0048] In addition, in the first core portion 11, the area where at least the flat plate portion 11g is located (preferably at least a portion of the flat plate portion 11g and the transition portion 11f) has both shaping and shape retention properties.

[0049] The second core 12 is a long strip extending from the base end of the first core 11 to the base end side of the guide wire 100. The second core 12 has a base 12a and a second joint 12b sequentially from the base end to the front end side, and each part is integrally formed.

[0050] The base 12a extends a predetermined length from the base end of the guide wire 100 at the base end of the second joint 12b. The outer diameter of the base 12a is approximately constant and is approximately equal to the outer diameter of the first outer diameter constant portion 11b.

[0051] The second joint 12b is the part that joins with the first joint 11a. The outer diameter of the second joint 12b is larger than the outer diameter of the base 12a, but equal to the outer diameter of the first joint 11a. The first joint 11a and the second joint 12b can be joined by welding, brazing, or soldering.

[0052] Here, specific dimensions of the guide wire 100 are described. The total length of the guide wire 100 along its major axis is 1000 mm to 4500 mm. The length of the first core portion 11 is 150 mm to 1000 mm. The combined length of the first connecting portion 11a and the first outer diameter constant portion 11b is 10 mm to 300 mm. The length of the first tapered portion 11c is 10 mm to 100 mm. The length of the second outer diameter constant portion 11d is 10 mm to 300 mm. The length of the second tapered portion 11e is 10 mm to 100 mm. The length of the transition portion 11f is 1 mm to 20 mm. The length of the flat portion 11g is 1 mm to 20 mm.

[0053] The outer diameters of the first joint 11a and the first constant outer diameter 11b are 0.2 mm to 1 mm. The outer diameters of the first tapered portion 11c and the second constant outer diameter 11d are 0.1 mm to 1 mm. The outer diameter of the second tapered portion 11e is 0.05 mm to 1 mm. The thickness of the transition portion 11f is 0.01 mm to 1 mm, and the width is 0.05 mm to 1 mm. The thickness of the flat plate portion 11g is 0.01 mm to 1 mm, and the width is 0.05 mm to 1 mm.

[0054] The length of the second core 12 is 850mm to 3500mm. The outer diameter of the second core 12 is 0.2mm to 1mm.

[0055] The first core 11 and the second core 12 can be formed from various metallic materials such as Ni-Ti alloys (superelastic alloys), stainless steel (SUS302, SUS304, SUS303, SUS316, SUS316L, SUS316J1, SUS316J1L, SUS405, SUS430, SUS434, SUS444, SUS429, SUS430F), piano wire, and cobalt alloys. Furthermore, the first core 11 is preferably formed from a material with lower rigidity than the material of the second core 12. For example, the first core 11 is formed from a Ni-Ti alloy, and the second core 12 is formed from stainless steel. It should be noted that the materials used to form the first core 11 and the second core 12 are not limited to the examples described above. Alternatively, the first core 11 and the second core 12 can also be formed from the same material.

[0056] Furthermore, the core component 10 may not be formed from multiple components as in the first core 11 and the second core 12, but may be formed from a single continuous component.

[0057] <Lumen>

[0058] The cavity body 20 is a component formed by winding a wire into a spiral shape relative to the core component 10. In this embodiment, the cavity body 20 is formed by a first coil 21 and a second coil 22 disposed on the base end side of the first coil 21. The first coil 21 is disposed from the front end to the middle portion of the first core 11. The second coil 22 is disposed from the middle portion of the first core 11 to the base end side. It should be noted that the cavity body 20 may also be formed by a single coil. The cavity body 20 may also be formed by three or more coils.

[0059] The first coil 21 surrounds the first core 11 of the core component 10 and is fixed to the first core 11. The first coil 21 is coaxially arranged with the first core 11. The length of the first coil 21 is 3mm to 60mm.

[0060] The first coil 21 is formed by winding wires into a spiral shape with gaps between adjacent wires. The gap between adjacent wires of the first coil 21 is 1 μm to 10 μm. Preferably, the gap between adjacent wires of the first coil 21 is equal.

[0061] The second coil 22 surrounds the first core 11 of the core component 10 and is fixed to the first core 11. The second coil 22 is coaxially arranged with the first core 11. The length of the second coil 22 is 10mm to 400mm.

[0062] The second coil 22 has a tightly wound portion and a loosely wound portion. The tightly wound portion is formed by tightly winding adjacent wires into a spiral shape without gaps between them. The loosely wound portion is formed by loosely winding adjacent wires into a spiral shape with gaps between them. In this embodiment, the tightly wound portion of the second coil 22 is located at the front end and the base end of the second coil 22, and the loosely wound portion is located between the tightly wound portion on the front end side and the tightly wound portion on the base end side. It should be noted that the second coil 22 may also be composed only of a tightly wound portion without a loosely wound portion.

[0063] The base end of the first coil 21 and the front end of the second coil 22 are partially intertwined. That is, the wire at the base end of the first coil 21 and the wire at the front end of the second coil 22 are arranged alternately along their long axis. This prevents the first coil 21 and the second coil 22 from separating. The length by which the base end of the first coil 21 and the front end of the second coil 22 are intertwined is 0.1 mm to 2 mm. The winding directions of the first coil 21 and the second coil 22 are consistent so that they can be intertwined.

[0064] The outer diameter of the wires forming the first coil 21 and the second coil 22 is 20 μm to 90 μm, preferably 30 μm to 70 μm. In this embodiment, the outer diameter of the wire forming the first coil 21 is larger than the outer diameter of the wire forming the second coil 22. Furthermore, the wires forming the first coil 21 and the second coil 22 may not be a single wire, but may be a stranded wire composed of two or more wires.

[0065] The wire material for the first coil 21 and the second coil 22 is not particularly limited, and can be formed from metals such as stainless steel, superelastic alloys, cobalt alloys, gold, platinum, and tungsten, or alloys containing them. As an example, the first coil 21 is a platinum alloy that is softer and has higher imaging properties than the second coil 22, and the second coil 22 is made of stainless steel. Pt-Ir, Pt-Ni, and Pt-W are preferred platinum alloys.

[0066] The outer diameters of the first coil 21 and the second coil 22 are preferably constant from the front end to the base end. In this embodiment, the outer diameters of the first coil 21 and the second coil 22 are approximately equal. Therefore, the outer diameter of the cavity 20 is approximately constant from the front end to the base end. The outer diameters of the first coil 21 and the second coil 22 are 0.15 mm to 2 mm.

[0067] The material, outer diameter, cross-sectional shape, and spacing of the wires forming the first coil 21 and the second coil 22 can be appropriately selected according to the purpose of the guide wire 100. Furthermore, the cross-sectional shape of the wire is preferably circular, but it can also be elliptical, polygonal, etc. For wires with a non-circular cross-sectional shape, the center of the cross-section can be the centroid of the wire's cross-section.

[0068] <Fixed Part>

[0069] The fixing part 30 is a component for fixing the lumen 20 to the core component 10. In this embodiment, the fixing part 30 includes: a front end fixing part 31 for fixing the front end of the lumen 20 to the front end fixing part of the core component 10; a middle fixing part 32 for fixing the middle part of the lumen 20 to the core component 10; and a base end fixing part 33 for fixing the base end of the lumen 20 to the core component 10.

[0070] The material forming the fixing part 30 can be a hard soldering material or a soft soldering material. Hard soldering materials include gold soldering, silver soldering, etc. Soft soldering materials include Sn-Ag alloy soft soldering materials, Sn-Pb alloy soft soldering materials, etc. The material forming the fixing part 30 can also be an adhesive.

[0071] The front end fixing part 31 fixes the front end of the first coil 21 to the flat plate part 11g of the first core part 11. The front end fixing part 31 is located at the foremost end of the guide wire 100, and its outer surface is smooth and roughly hemispherical.

[0072] The intermediate fixing part 32 fixes the base end of the first coil 21 and the front end of the second coil 22 to the second cone 11e of the first core 11 via the cylindrical member 32a. The intermediate fixing part 32 is located in the first core 11 at the position where the base end of the first coil 21 and the front end of the second coil 22 are intertwined.

[0073] A cylindrical member 32a is disposed between the inner circumferential surface of the cavity 20 and the outer circumferential surface of the core member 10. The cylindrical member 32a reduces the gap between the inner circumferential surface of the cavity 20 and the outer circumferential surface of the core member 10, thereby coaxially fixing the cavity 20 and the core member 10. In this embodiment, the outer diameter of the front end of the cylindrical member 32a is smaller than the outer diameter of the base end of the cylindrical member 32a. Therefore, as... Figure 2 As shown, the first coil 21 with a smaller inner diameter and the second coil 22 with a larger inner diameter can be coaxially fixed relative to the core member 10. The outer diameter of the front end and the outer diameter of the base end of the cylindrical member 32a can be appropriately selected according to the inner diameter of the first coil 21 and the inner diameter of the second coil 22. The cylindrical member 32a can be formed of metal or resin material. It should be noted that the guide wire 100 may also be without the cylindrical member 32a.

[0074] The base end fixing part 33 fixes the base end of the second coil 22 to the second outer diameter constant part 11d of the first core 11.

[0075] <Covering>

[0076] The cover layer 40 includes a first cover layer 41, a second cover layer 42, and a third cover layer 43. The cover layer 40 can be formed of a material that can reduce friction between the guidewire 100 and the blood vessel or catheter. Thus, the cover layer 40 improves the operability and safety of the guidewire 100.

[0077] The first coating layer 41 covers the outer surface of each part of the first core 11 (the cavity 20 and the fixing part 30) and a part of the first core 11 (the second outer diameter constant part 11d).

[0078] The second coating layer 42 covers the portion of the core component 10 located on the side closer to the base end than the cavity 20. The second coating layer 42 covers the base end portion (first tapered portion 11c, first outer diameter constant portion 11b) of the first core portion 11 and the outer surface of the second core portion 12. That is, the portion of the core component 10 located on the side closer to the base end than the cavity 20, covered by the second coating layer 42 covers all portions except for the first joint portion 11a and the second joint portion 12b.

[0079] The third coating layer 43 covers the outer surfaces of the first joint 11a and the second joint 12b.

[0080] It should be noted that the second coating layer 42 may also cover the entire portion of the core component 10 located on the side closer to the base end of the lumen 20. In this case, the third coating layer 43 is not provided. Alternatively, the second coating layer 42 may not cover a portion of the portion of the core component 10 located on the side closer to the base end of the lumen 20. In this case, the third coating layer 43 may be provided on the portion not covered by the second coating layer 42.

[0081] The first coating layer 41 can be formed from a hydrophilic polymer. Examples of hydrophilic polymers forming the first coating layer 41 include cellulose-based polymers, polyethylene oxide-based polymers, maleic anhydride-based polymers (e.g., maleic anhydride copolymers such as methyl vinyl ether-maleic anhydride copolymers), acrylamide-based polymers (e.g., block copolymers of polyacrylamide, glycidyl methacrylate-dimethacrylamide), water-soluble nylon, polyvinyl alcohol, polyvinylpyrrolidone, and derivatives thereof.

[0082] The second coating layer 42 and the third coating layer 43 can be made of low-friction materials. Examples of low-friction materials include polyolefins such as polyethylene and polypropylene, polyvinyl chloride, polyesters (PET, PBT, etc.), polyamides, polyimides, polyurethanes, polystyrene, polycarbonates, silicone resins, fluoropolymers (PTFE, ETFE, etc.), or composites thereof.

[0083] It should be noted that the materials forming the first coating layer 41, the second coating layer 42, and the third coating layer 43 are not limited to the materials described above. The first coating layer 41, the second coating layer 42, and the third coating layer 43 may also be formed of different materials along the long axis of the core component 10. For example, the material covering the front end of the first core 11 in the second coating layer 42 may be different from the material covering the base end of the first core 11. Furthermore, the number of layers in each of the first coating layer 41, the second coating layer 42, and the third coating layer 43 may be multiple. It should also be noted that any one of the first coating layer 41, the second coating layer 42, and the third coating layer 43 may be omitted.

[0084] The guidewire 100 of this embodiment possesses both shape-adaptability and shape retention at its tip. Shape-adaptability refers to the property that allows the operator to shape the tip of the guidewire 100. With respect to the guidewire 100, shaping the tip to achieve a desired shape improves the maneuverability of the guidewire 100 within the blood vessel and the selectivity of the vessel in branch sections. The shape of the guidewire 100 achieved through shaping depends on the inner diameter and shape of the patient's blood vessel. Therefore, the guidewire 100 is preferably easily shaped into the desired shape. That is, excellent shape-adaptability is required.

[0085] Shape retention refers to the property of maintaining the shape of the guidewire 100's tip, as assigned by the operator, during manipulation within a blood vessel. Generally, the guidewire 100 is shaped into a curved shape with a radius of curvature relatively large compared to the vessel's inner diameter. Therefore, the guidewire 100 deforms according to the vessel's inner diameter and shape. Furthermore, the tip of the guidewire 100, by abutting against the vessel wall at a branch or hanging on a stent, is sometimes unintentionally bent into a U-shape. Also, when passing through narrow sections, the guidewire 100 is sometimes intentionally bent into a U-shape to prevent perforation. Thus, the tip of the guidewire 100 is subjected to deformable external forces during manipulation within the blood vessel. If the guidewire 100's resilience relative to these external forces is low, it undergoes plastic deformation and cannot maintain the shape assigned by the operator, reducing operability and vessel selectivity. If the tip of the guidewire deforms, the operator needs to remove the guidewire from the vessel and reshape it. When the guidewire becomes deformed to a degree that is difficult to reshape, it needs to be replaced with another guidewire. This prolongs the procedure time and increases the burden on both the operator and the patient. Therefore, the guidewire 100 preferably has the property of being able to recover its original shape, as imparted by the operator, even if deformed by external force during intravascular manipulation, once the external force is removed. In other words, the guidewire 100 requires excellent shape retention.

[0086] The guide wire 100, which combines both shaping and shape retention, is obtained by controlling the elastic deformation power and martensitic hardness of the tip of the guide wire 100, which is formed of Ni-Ti alloy, within a specified range.

[0087] The elastic deformation power and martensite hardness are calculated from the load-displacement curve obtained by instrumented indentation hardness testing of the flat portion 11g of the guide wire 100. Elastic deformation power is the proportion of the work done in elastic deformation relative to the total work (the sum of the work done in plastic deformation and the work done in elastic deformation). Martensite hardness is the value obtained by dividing the test load by the surface area penetrated by the indenter in the instrumented indentation hardness test.

[0088] Materials with high elastic deformation power exhibit high shape recovery due to hyperelasticity. Therefore, the flat portion 11g of the guide wire 100, formed from a material with high elastic deformation power, easily recovers its original shape even when an external force is applied and removed. Thus, the higher the elastic deformation power, the lower the shapeability and the higher the shape retention of the flat portion 11g. On the other hand, materials with low elastic deformation power are prone to plastic deformation. Therefore, the flat portion 11g formed from a material with low elastic deformation power undergoes plastic deformation when an external force is applied, and easily maintains its shape even when the external force is removed. Thus, the lower the elastic deformation power, the higher the shapeability of the flat portion 11g, but the lower its shape retention.

[0089] Materials with high Marvin hardness are hard. Therefore, the flat portion 11g of the guidewire 100 formed from a material with high Marvin hardness is less prone to deformation under external force. Thus, the higher the Marvin hardness, the lower the shapeability of the flat portion 11g and the higher its shape retention. On the other hand, the flat portion 11g of the guidewire 100 formed from a material with low Marvin hardness is prone to plastic deformation even when subjected to small external forces within the blood vessel. Therefore, the lower the Marvin hardness, the higher the shapeability of the flat portion 11g and the lower its shape retention.

[0090] The magnitude of the external force exerted on the guidewire 100 within the blood vessel is smaller than the external force applied by the operator for shaping. Therefore, the tip of the guidewire 100 possesses the property of being deformable under the larger force applied by the operator for shaping, but not plastically deformed under the smaller force applied during surgery and able to recover to its original shape, thus achieving both shaping and shape retention.

[0091] Martens hardness has a greater impact on shaping and shape retention than elastic deformation power. Therefore, even controlling only the elastic deformation power cannot improve both shaping and shape retention; proper control of martens hardness is particularly important.

[0092] The guidewire 100 of this embodiment has a flat portion 11g with an elastic deformation power of 46.0% to 59.5% and a martensitic hardness of 1300 N / mm. 2 ~3000N / mm 2 The formation of Ni-Ti alloy.

[0093] The tip of the guidewire 100, with its flat section 11g possessing the aforementioned range of elastic deformation power and Marlowe hardness, exhibits the following physical properties: it can deform under a large force applied by the operator for shaping, but will not plastically deform under a small force applied during surgery and can return to its original shape. Therefore, the guidewire 100 can be shaped by the operator, and even if the tip is subjected to a deformable external force within the blood vessel, it can return to its original shape. Thus, the guidewire maintains the high operability and vascular selectivity imparted through shaping during surgery. Furthermore, the operator does not need to remove the guidewire 100 from the blood vessel, reshape it, or replace it with another guidewire, thus simplifying the procedure. This shortens the operation time, thereby reducing the burden on both the operator and the patient.

[0094] Furthermore, the flat portion 11g of the guidewire 100 preferably has an elastic deformation power of 46.0% to 59.5% and a martensitic hardness of 1300 N / mm. 2 ~2120N / mm 2 The elastic deformation power of the flat portion 11g of the guidewire 100 is in the range of 46.0% to 59.5%, and the martensitic hardness is 1300 N / mm.2 ~2120N / mm 2 The range of the first core 11 is such that the flat portion 11g of the first core 11 becomes more flexible, thus further improving its shapeability.

[0095] In addition, in order to ensure that the elastic deformation power and martensitic hardness of the flat portion 11g of the guide wire 100 are within the above-mentioned range, it is preferable to perform heat treatment on the front end of the core component 10.

[0096] The flat plate portion 11g is formed by stamping the front end of the first core portion 11, which is made of Ni-Ti alloy. Due to the strain introduced by the stamping process, the hyperelasticity of the flat plate portion 11g is reduced compared to the Ni-Ti alloy before stamping. Therefore, the elastic deformation power of the flat plate portion 11g after stamping is lower, resulting in poor shape retention. By performing heat treatment on the flat plate portion 11g after stamping, the strain of the flat plate portion 11g is removed, and the hyperelasticity is improved. As a result, the elastic deformation power of the flat plate portion 11g is higher, and the shape retention is improved. Furthermore, the flat plate portion 11g after stamping is harder due to work hardening compared to the Ni-Ti alloy before stamping. Therefore, the martensitic hardness of the flat plate portion 11g after stamping is high, resulting in low formability. By performing heat treatment on the flat plate portion 11g after stamping, the flat plate portion 11g is softened. As a result, the martensitic hardness of the flat plate portion 11g is reduced, and the formability is improved. In this way, by performing heat treatment on the flat plate portion 11g after stamping, the elastic deformation power and martensitic hardness of the tip of the guide wire 100, which is formed of Ni-Ti alloy, can be controlled within a specified range. Thus, the guide wire 100 can possess both shaping and shape retention properties.

[0097] The heat treatment is preferably performed on at least a portion of the flat plate portion 11g and the transition portion 11f of the first core portion 11. That is, the guide wire 100 according to this embodiment has a heat treatment region H that extends continuously along its long axis from the front end of the flat plate portion 11g to at least a portion of the transition portion 11f. One end of the heat treatment region H of the guide wire 100 coincides with the front end of the flat plate portion 11g, and the other end is located in the transition portion 11f. In this specification, the heat treatment region H refers to the region where an oxide film is formed on at least a portion of the circumferential surface of the outer surface of the first core component through heat treatment. Therefore, an oxide film is formed on the outer surface of the guide wire 100 from the front end of the flat plate portion 11g to at least a portion of the transition portion 11f along its long axis. Furthermore, in this specification, the total length of the guide wire 100 from one end of the heat treatment region H to the other along its long axis is referred to as the heat treatment length. The heat treatment length of the guide wire 100 is longer than the length of the flat plate portion 11g along its long axis.

[0098] The guidewire 100 is able to suppress abrupt changes in rigidity along its long axis by having a heat-treated region H that extends continuously from the front end of the flat plate portion 11g to the transition portion 11f. Figures 4A to 4C This is a schematic diagram showing the rigidity of the front end of the first core 11 when the guide wire 100 is heat-treated. Figure 4A , Figure 4C In the middle, the dots on the outer surface of the first core 11 represent the level of rigidity. The denser the dots, the lower the rigidity, and the sparser the dots, the higher the rigidity. Figures 4A to 4C The double-dotted line in the diagram is an imaginary line dividing the area of ​​the flat plate portion 11g, the transition portion 11f, and the second conical portion 11e. For example... Figure 4A As shown, in the guidewire 100, the flat plate portion 11g is a flat plate shape with a small thickness. Therefore, the rigidity of the flat plate portion 11g is low and constant along the long axis. On the other hand, the transition portion 11f is a wedge shape in which the thickness gradually increases and the width gradually decreases from the flat plate portion 11g to the second tapered portion 11e. Therefore, the rigidity of the transition portion 11f is equal to that of the flat plate portion 11g at the front end, and gradually increases from the front end to the base end. Here, if the first core portion 11 is heat-treated, the rigidity of the heat-treated portion of the first core portion 11 is reduced. Therefore, as Figure 4B As shown, if only a portion of the flat plate 11g is heat-treated, the rigidity of the flat plate 11g changes abruptly at the base end of the heat-treated region H. Alternatively, if only the flat plate 11g is heat-treated, the rigidity of the first core 11 changes abruptly at the boundary between the flat plate 11g and the transition portion 11f. The guide wire 100 is prone to bending and sagging at points where rigidity changes abruptly along its long axis. In this embodiment, as... Figure 4C As shown, it is preferable to perform heat treatment on the flat plate portion 11g along its entire length, and also on a portion of the transition portion 11f. This suppresses abrupt changes in the rigidity of the guidewire 100 along its long axis, improving its resistance to sagging.

[0099] It should be noted that prolapse refers to a condition where, with the tip of the guidewire 100 inserted from the trunk towards the lateral branch, the basal portion of the guidewire 100 is more locally bent than the tip, and this bent portion is further away from the tip than the branch extending from the trunk towards the lateral branch. If the guidewire 100 is in this state, the pushing force and torque applied to the basal end of the guidewire 100 can only be transmitted to the bent portion, making it difficult for the operator to guide the tip of the guidewire 100 into the tip of the lateral branch. Furthermore, because the tip of the catheter advancing along the guidewire 100 is guided towards the bent portion, it is difficult for the operator to advance the catheter towards the lateral branch.

[0100] The base of the heat-treated region H of the guidewire 100 is preferably located at the transition portion 11f. That is, the base of the heat-treated region H of the guidewire 100 is preferably not located at the second cone portion 11e. The second cone portion 11e, which has not undergone cold working, will experience a decrease in hyperelasticity during heat treatment, making it prone to plastic deformation. As a result, the guidewire 100 is prone to kinking within the blood vessel. In this embodiment, as... Figure 4C As shown, only the flat plate portion 11g and the transition portion 11f after cold working are heat-treated. As a result, the plastic deformation of the guide wire 100 due to the reduction of hyperelasticity is suppressed, and the kink resistance is improved.

[0101] The length of the guidewire 100 from the tip of the transition portion 11f to the base of the heat-treated region H along its long axis is preferably 10% to 100% of the total length of the transition portion 11f along its long axis. This allows the guidewire 100 to possess shape retention and shape conformability, and improves its resistance to prolapse and kinking. If the heat-treated length is longer than the aforementioned range, the portion of the first core 11 that has not undergone cold working, such as the second cone portion 11e, will be heat-treated. If the portion of the first core 11 that has not undergone cold working is heat-treated, its hyperelasticity decreases, making it prone to plastic deformation. As a result, the guidewire 100 is prone to kinking within the blood vessel. Furthermore, if the heat-treated length is shorter than the aforementioned range, and only the flat portion 11g is heat-treated, a sharp change in rigidity occurs in the first core 11 or at the boundary between the flat portion 11g and the transition portion 11f, making prolapse more likely.

[0102] The proportion of the length of the guidewire 100 along its long axis from the tip of the transition portion 11f to the base of the heat-treated region H in the long axis direction is more preferably 55% to 65% of the total length of the transition portion 11f along its long axis direction. This allows the guidewire 100 to possess shape-forming properties and shape retention, and further improves its resistance to sagging and kinking. When the length along its long axis from the tip of the transition portion 11f to the base of the heat-treated region H is greater than 65% of the total length of the transition portion 11f along its long axis direction, the length of the portion of the transition portion 11f whose rigidity is reduced due to heat treatment becomes longer. Therefore, when the guidewire 100 is pushed in with its tip inserted from the main branch to the side branch, the pushing force is not transmitted to the tip of the guidewire 100, causing it to bend at the transition portion 11f located on the main branch, making sagging more likely. On the other hand, when the length along the long axis from the front end of the transition portion 11f to the base end of the heat treatment region H is less than 55% of the length along the long axis of the transition portion 11f, the length of the high-rigidity portion of the transition portion 11f becomes longer. Furthermore, since the base end of the heat treatment region H is located at the front end of the low-rigidity transition portion 11f, the rigidity of the guidewire 100 changes abruptly at the base end of the heat treatment region H, making it prone to sagging. In the heat treatment region H, by setting the length along the long axis from the front end of the transition portion 11f to the base end of the heat treatment region H to more than 55% and less than 65% of the length along the long axis of the transition portion 11f, the guidewire 100 can further improve its resistance to sagging and kinking.

[0103] Various conditions can be appropriately set when heat-treating the front end of the core component 10. For example, the heat treatment temperature is in the range of 300°C to 650°C and the time is in the range of 3 to 60 minutes.

[0104] Heat treatment has the following effects: it softens the plate portion 11g, which hardens during cold working, making it easier to deform; and it moderately improves the superelasticity by removing the strain from the plate portion 11g, which has decreased in superelasticity due to strain introduced during cold working. Therefore, heat treatment is particularly effective as a method for imparting shape-forming properties and shape retention to the guide wire 100. It should be noted that the method for imparting shape-forming properties and shape retention to the front end of the core component 10 is not limited to heat treatment; other methods may be applied as long as the elastic deformation power and martensitic hardness are within the aforementioned ranges.

[0105] [Effects]

[0106] As described above, the guide wire 100 according to this embodiment includes a long strip core member 10 with a flat portion 11g at the front end. The flat portion 11g is made of a material with an elastic deformation power of 46.0% to 59.5% and a Martens hardness of 1300 N / mm². 2 Above 3000N / mm 2The following Ni-Ti alloy is formed.

[0107] With this configuration, the guidewire 100 possesses the following physical properties: it can deform under a large force applied by the operator for shaping, but will not plastically deform under a small force applied during surgery and can return to its original shape. That is, the guidewire 100 combines both shaping and shape retention. Therefore, the guidewire 100 can be shaped by the operator, and even under an external force that deforms its proximal end within the blood vessel, it can return to its original shape. Thus, the guidewire 100 maintains the high operability and vascular selectivity gained through shaping during surgery. Furthermore, the operator does not need to remove the guidewire 100 from the blood vessel, reshape it, or replace it with another guidewire, thus simplifying the procedure. This shortens the operation time, thereby reducing the burden on both the operator and the patient.

[0108] Alternatively, the guide wire 100 described in this embodiment can also be configured to have a martensitic hardness of 1300 N / mm. 2 The above is 2120 N / mm 2 the following.

[0109] With this configuration, the flat portion 11g of the first core portion 11 located at the front end of the core component 10 of the guidewire 100 becomes more flexible, and its shapeability is further improved.

[0110] In addition, the core component 10 of the guide wire 100 according to this embodiment has a flat plate portion 11g and a transition portion 11f extending from the base end of the flat plate portion 11g along the long axis direction to the base end side in sequence from the front end side. The core component 10 may also be configured to have a heat treatment region H extending from the front end of the flat plate portion 11g to the transition portion 11f.

[0111] With this configuration, the first core 11 can suppress the abrupt change in rigidity along the long axis at the base of the heat-treated region H, thus enabling it to possess shape retention and shape-forming properties, and improving its resistance to sagging and kinking.

[0112] Alternatively, the proportion of the length of the guide wire 100 from the front end of the transition portion 11f to the base end of the heat treatment region H along the long axis direction in the length of the transition portion 11f along the long axis direction can be set to 10% or more and 100% or less.

[0113] With this configuration, the guidewire 100 can possess shape-forming and shape-maintaining properties, and improve its resistance to sagging and kinking.

[0114] Alternatively, the proportion of the length of the guide wire 100 from the front end of the transition portion 11f to the base end of the heat treatment region H along the long axis direction in this embodiment can be set to 55% or more and 65% or less in the length of the transition portion 11f along the long axis direction.

[0115] This configuration further suppresses the abrupt change in rigidity of the guidewire 100 along its long axis, thus further improving its resistance to sagging and kinking.

[0116] Furthermore, the manufacturing method of the guide wire 100 according to this embodiment includes: a step of cold-working the front end of the core component 10, which has a core component 10, and having a flat plate portion 11g and a transition portion 11f extending from the base end of the flat plate portion 11g along the long axis towards the base end; and a step of having an elastic deformation power of 46.0% to 59.5% and a Martens hardness of 1300 N / mm. 2 Above 3000N / mm 2 The following is a process of heat-treating at least a portion of the flat plate portion 11g and the transition portion 11f.

[0117] The guidewire 100 manufactured by the above method possesses the following physical properties: it can deform under a large force applied by the operator for shaping, but it will not plastically deform under a small force applied during surgery and can return to its original shape. That is, the guidewire 100 can combine shaping and shape retention. As a result, the guidewire 100 can be shaped by the operator, and even if subjected to an external force that can deform the anterior end within the blood vessel, it can return to its original shape. Therefore, the guidewire 100 can maintain the high operability and vascular selectivity imparted by shaping during surgery. In addition, the operator does not need to remove the guidewire 100 from the blood vessel, reshape it, or replace it with another guidewire, thus simplifying the operation. As a result, the operation time is shortened, thus reducing the burden on the operator and the patient. Furthermore, heat treatment has the following effects: softening the plate portion 11g that hardens during cold working, making it easier to deform; and moderately improving the superelasticity by removing the strain from the plate portion 11g, which has reduced superelasticity due to the strain introduced during cold working. Therefore, heat treatment is a particularly effective method for imparting shape-forming properties and shape retention to the guidewire 100.

[0118] Example

[0119] The present invention will be described in more detail below through embodiments, but the scope of the present invention is not limited to the following embodiments.

[0120] Hereinafter, the "manufacturing of the guidewire," "evaluation method," and "evaluation results" of the guidewires 100 of the Examples and Comparative Examples will be described in detail with reference to Tables 1 to 4. Table 1 shows the manufacturing conditions of Examples 1 to 16, and Table 2 shows the manufacturing conditions of Comparative Examples 1 to 4. It should be noted that the "heat treatment ratio" in Tables 1 and 2 refers to the proportion of the length along the long axis from the front end of the transition portion 11f to the base end of the heat treatment region H in the length along the long axis of the transition portion 11f.

[0121] Table 1

[0122]

[0123] Table 2

[0124]

[0125] [Guidewire Manufacturing]

[0126] The manufacturing of the guidewire 100 according to the embodiments and comparative examples will be described below. It should be noted that in each embodiment and comparative example, the heat treatment performed in step 3 is performed at a temperature ranging from 300°C to 650°C for a time ranging from 3 minutes to 60 minutes.

[0127] <Example 1>

[0128] (Process 1)

[0129] The front end of the first core 11 (Ni content 54%–57% by mass) made of Ni-Ti alloy is subjected to a tapered machining process in which the outer diameter gradually decreases from the base end to the front end. The outer diameter of the frontmost end is 80 μm.

[0130] (Process 2)

[0131] A 16mm section is punched from the front end of the first core portion 11 toward the base end to form a flat plate portion 11g and a transition portion 11f. At this time, the flat plate portion 11g, extending 9mm from the front end of the guidewire 100 toward the base end, is formed with a constant flat plate shape of 27μm thickness. The transition portion 11f, extending 7mm from the base end of the flat plate portion 11g toward the base end, is provided with a wedge shape whose thickness increases toward the base end.

[0132] (Process 3)

[0133] Heat treatment is performed on the 12.5 mm range from the front end to the base end of the first core 11 stamped in process 2.

[0134] (Step 4)

[0135] A cavity 20 formed by a first coil 21 and a second coil 22 is arranged around a portion of the flat portion 11g of the first core 11 to the second outer diameter constant portion 11d. The first coil 21 is a coil with a length of 28mm to 32mm formed by winding a platinum alloy wire (outer diameter: 0.340mm to 0.350mm, wire diameter: 58μm to 60μm). The second coil 22 is a coil with a length of 210mm to 220mm formed by winding a stainless steel wire (outer diameter: 0.340mm to 0.350mm, wire diameter: 38μm to 40μm). The front end of the first coil 21 is fixed to the flat portion 11g of the first core 11 by silver soldering. The base end of the first coil 21 and the front end of the second coil 22 are fixed to the second tapered portion 11e of the first core 11 via a metal cylindrical component 32a using Sn-Ag alloy soldering. The base end of the second coil 22 is fixed to the second outer diameter constant portion 11d of the first core 11 via Sn-Ag alloy soldering.

[0136] (Step 5)

[0137] The first core 11 and the second core 12 are joined together by resistance welding.

[0138] (Step 6)

[0139] A first coating layer 41 is formed by coating the outer surfaces of the first coil 21, the second coil 22, and a portion of the second outer diameter constant portion 11d with a hydrophilic polymer. A second coating layer 42 is formed by coating the outer surfaces of the first outer diameter constant portion 11b, the first cone portion 11c, and the second core portion 12 of the first core portion 11 with a fluorinated resin. A third coating layer 43 is formed by coating the outer surfaces of the first joint portion 11a and the second joint portion 12b with an organosilicon resin.

[0140] The guidewires of Examples 2 to 16 were manufactured according to the following method. It should be noted that steps 1, 2, and 4 to 6 of the guidewires of Examples 2 to 6 and 9 to 16 were manufactured according to the same method as in Example 1, and step 3 was manufactured according to the following method.

[0141] <Example 2>

[0142] In step 3, heat treatment is performed on the 13.0 mm range from the front end to the base end of the first core 11 stamped in step 2.

[0143] <Example 3>

[0144] In step 3, heat treatment is performed on the 13.8 mm range from the front end to the base end of the first core 11 stamped in step 2.

[0145] <Example 4>

[0146] In step 3, heat treatment is performed on the 13.6 mm range from the front end to the base end of the first core 11 stamped in step 2.

[0147] <Example 5>

[0148] In step 3, heat treatment is performed on the 12.8 mm range from the front end to the base end of the first core 11 stamped in step 2.

[0149] <Example 6>

[0150] In step 3, heat treatment is performed on the 13.3 mm range from the front end to the base end of the first core 11 stamped in step 2.

[0151] <Example 9>

[0152] In step 3, heat treatment is performed on the 7.2 mm range from the front end to the base end of the first core 11 stamped in step 2.

[0153] <Example 10>

[0154] In step 3, heat treatment is performed on the 9.3 mm range from the front end to the base end of the first core 11 stamped in step 2.

[0155] <Example 11>

[0156] In step 3, heat treatment is performed on the 10.3 mm range from the front end to the base end of the first core 11 stamped in step 2.

[0157] <Example 12>

[0158] In step 3, heat treatment is performed on the 11.7 mm range from the front end to the base end of the first core 11 stamped in step 2.

[0159] <Example 13>

[0160] In step 3, heat treatment is performed on the 14.4 mm range from the front end to the base end of the first core 11 stamped in step 2.

[0161] <Example 14>

[0162] In step 3, heat treatment is performed on the 16.0 mm range from the front end to the base end of the first core 11 stamped in step 2.

[0163] <Example 15>

[0164] In step 3, heat treatment is performed on the 18.9 mm range from the front end to the base end of the first core 11 stamped in step 2.

[0165] <Example 16>

[0166] In step 3, heat treatment is performed on the 20.6 mm range from the front end to the base end of the first core 11 stamped in step 2.

[0167] In addition, regarding the guidewires of Examples 7 and 8, steps 1 and 4 to 6 are manufactured in the same way as in Example 1, and steps 2 and 3 are manufactured in the following way.

[0168] <Example 7>

[0169] (Process 2)

[0170] A 16mm section is punched from the front end of the first core portion 11 toward the base end to form a flat plate portion 11g and a transition portion 11f. At this time, the 13mm section from the front end of the guidewire 100 toward the base end is designated as the flat plate portion 11g, forming a constant flat plate shape with a thickness of 32μm. The 3mm section from the base end of the flat plate portion 11g toward the base end is designated as the transition portion 11f, and is configured as a wedge shape with increasing thickness toward the base end.

[0171] (Process 3)

[0172] Heat treatment is performed on the 13.6 mm range from the front end to the base end of the first core 11 stamped in process 2.

[0173] <Example 8>

[0174] (Process 2)

[0175] A 16mm section is punched from the front end of the first core portion 11 toward the base end to form a flat plate portion 11g and a transition portion 11f. At this time, the 13mm section from the front end of the guidewire 100 toward the base end is designated as the flat plate portion 11g, forming a constant flat plate shape with a thickness of 32μm. The 3mm section from the base end of the flat plate portion 11g toward the base end is designated as the transition portion 11f, and is configured as a wedge shape with increasing thickness toward the base end.

[0176] (Process 3)

[0177] Heat treatment is performed on the 13.7 mm range from the front end to the base end of the first core 11 stamped in process 2.

[0178] Comparative Examples 1 to 4 were manufactured according to the following method. It should be noted that steps 1, 2, 4 to 6 of Comparative Examples 1 and 2 were manufactured according to the same method as in Example 1, and step 3 was manufactured according to the following method.

[0179] <Comparative Example 1>

[0180] In process 3, the first core 11 stamped in process 2 is not subjected to heat treatment.

[0181] <Comparative Example 2>

[0182] In step 3, heat treatment is performed on the 13.7 mm range from the front end to the base end of the first core 11 stamped in step 2.

[0183] In addition, Comparative Examples 3 and 4 were manufactured according to the following method. Step 1 and steps 4 to 6 of Comparative Examples 3 and 4 were manufactured according to the same method as in Example 1, and steps 2 and 3 were manufactured according to the following method.

[0184] <Comparative Example 3>

[0185] (Process 2)

[0186] A 16mm section is punched from the front end of the first core portion 11 toward the base end to form a flat plate portion 11g and a transition portion 11f. At this time, the 13mm section from the front end of the guidewire 100 toward the base end is designated as the flat plate portion 11g, forming a constant flat plate shape with a thickness of 32μm. The 3mm section from the base end of the flat plate portion 11g toward the base end is designated as the transition portion 11f, and is configured as a wedge shape with increasing thickness toward the base end.

[0187] (Process 3)

[0188] Heat treatment is performed on the 14.3 mm range from the front end to the base end of the first core 11 stamped in process 2.

[0189] <Comparative Example 4>

[0190] (Process 2)

[0191] A 16mm section is punched from the front end of the first core portion 11 toward the base end to form a flat plate portion 11g and a transition portion 11f. At this time, the 13mm section from the front end of the guidewire 100 toward the base end is designated as the flat plate portion 11g, forming a constant flat plate shape with a thickness of 32μm. The 3mm section from the base end of the flat plate portion 11g toward the base end is designated as the transition portion 11f, and is configured as a wedge shape with increasing thickness toward the base end.

[0192] (Process 3)

[0193] Heat treatment is performed on the 13.0 mm range from the front end to the base end of the first core 11 stamped in process 2.

[0194] [Evaluation Method]

[0195] In Examples 1 to 16 and Comparative Examples 1 to 4, the evaluation of guidewire 100 was carried out according to the following method.

[0196] <Determination of Elastic Deformation Power and Martens Hardness>

[0197] -Device-

[0198] Shimadzu Corporation DUH-211S Dynamic Ultra-Micro Rigidity Tester

[0199] -Determination Conditions-

[0200] • Measuring indenter: Triangular pyramid indenter (115° angle between edges) equipment accessory (Triangular 115)

[0201] • Environmental conditions: Temperature 22±1℃

[0202] -Determination methods and procedures-

[0203] • Test method: Load-unload test (in accordance with "Instrumented indentation hardness" ISO 14577-1)

[0204] • Indentation depth: 0.5μm

[0205] • Duration: 0 seconds

[0206] • Measurement locations: Any 10 locations on a cross-section parallel to the plane, viewed from the thickness direction of the 11g plate portion.

[0207] -Calculation Method-

[0208] The elastic deformation power and martensitic hardness of the guide wire 100 in each embodiment and comparative example are the average values ​​of measurements taken at any 10 locations in a cross-section parallel to the plane, viewed from the thickness direction of the flat plate portion 11g. The elastic deformation power is set to one decimal place, and the martensitic hardness is set to an integer.

[0209] <Formability Test>

[0210] The shaping test was conducted as follows. First, the front 5mm portion of the guidewire 100 was placed on a silicone rubber plate and a stainless steel round bar mounted on a roughly horizontal surface. Clamp the rod and press it down with a load of 100g. Next, pull the guidewire 100 out of the silicone rubber plate vertically and visually observe the shape of the tip of the guidewire 100. In the evaluation, cases where the tip of the guidewire 100 is significantly deformed compared to before the test are marked as "0", cases where deformation occurs but is minor are marked as "△", and cases where there is no deformation are marked as "×".

[0211] <Shape retention test>

[0212] The shape retention test was conducted as follows. The guidewire 100 was deformed and shaped with a radius of curvature of 3.5 mm from a position 2 mm to 7 mm from its tip. The shaped guidewire 100 was then inserted into a U-shaped passage with a radius of curvature of 15 mm, rotated alternately left and right for a total of 10 turns, and then withdrawn. The shape of the tip of the guidewire 100 was then confirmed. In the evaluation, when a perpendicular line was drawn from the tip of the guidewire 100 to the central axis C, if the distance between the foot of the perpendicular before the test and the foot of the perpendicular after the test on the central axis C was within 1 mm, the shape was considered to be retained and marked "0"; if the distance was greater than 1 mm, the shape was considered not to be retained and marked "×". It should be noted that the smaller the radius of curvature of the U-shaped passage of the guidewire 100, the greater the external force, and the more difficult it is to maintain the shaped form.

[0213] <Sagging Resistance Test>

[0214] The sagging resistance test is conducted as follows. First, prepare... Figure 5A The branch model 200 shown is formed from a tube made of silicone resin. The branch model 200 has a main trunk 210 and a plurality of side branches 220 arranged along the long axis of the main trunk 210. The inner diameter of the main trunk 210 is 3 mm, and the inner diameter of the side branches 220 is 2 mm. Figure 5A In the middle, the angle θ (θ1~θ7) formed by the central axis of the main trunk 210 and the central axis of the lateral branch 220 on the front end side is set as θ1=90°, θ2=100°, θ3=110°, θ4=120°, θ5=130°, θ6=140°, θ7=150°.

[0215] Next, the tip of the guidewire 100 is shaped. For example... Figure 5B As shown, the guidewire 100 is shaped such that at the first bending point P1, located 1 mm from the tip of the guidewire 100, and the second bending point P2, located 5 mm from the tip, each point is deformed in the same direction by approximately 135°. Next, the guidewire 100 is inserted into each side branch 220 through the insertion port 200a of the water-filled branch model 200. The maximum angle θ among the side branches 220 into which the guidewire 100 can be inserted is recorded. If the maximum angle θ into which the guidewire 100 can be inserted is small, prolapse is considered likely to occur. Therefore, in the evaluation, among the side branches 220 into which the guidewire 100 can be inserted, if the maximum angle θ is θ≤100°, it is marked as "×"; if the angle θ is 100°<θ≤110°, it is marked as "△"; and if the angle θ is 110°<θ≤120°, it is marked as "〇".

[0216] <Twist Resistance Test>

[0217] The kink resistance test shall be conducted according to the following method. Figure 6As shown, a narrow model 300 is prepared, with one side of a tube with an inner diameter of 2.5 mm serving as the occluded end. The tip of the guide wire 100 is shaped as follows: Figure 5B The shape shown. The tip of the guidewire 100 is inserted into the opening of the narrow model 300 filled with water, like... Figure 6 The double-dotted dashed line indicates that the guide wire 100 is positioned abutting against the occluded end. Next, while applying torque, the guide wire 100 is pushed forward 10mm, as shown. Figure 6 The guide wire 100 is bent into a U-shape as shown by the solid line. Then, it is pulled 10 mm along its long axis to return it to its unbent U-shape state. This operation is performed a total of 3 times. The tester applies torque to the guide wire 100 by rotating it one revolution while holding the base end of the guide wire 100. The guide wire 100 is then removed from the narrow model 300, and the bending height L of the guide wire 100 is confirmed using a digital microscope. Figure 7 As shown, "bending height L" refers to the length of the guidewire 100 in its natural state, on the plane passing through the central axis C of the guidewire 100, from the tip of the guidewire 100 before shaping (straight state) to the tip of the guidewire 100 after the kink resistance test. In the evaluation, if the bending height L of the guidewire 100 after the kink resistance test is less than 4 mm, it is marked as "0"; if the bending height L is 4 mm or more, it is marked as "×".

[0218] [Evaluation Results]

[0219] Table 3 shows the evaluation results of Examples 1 to 16, and Table 4 shows the evaluation results of Comparative Examples 1 to 4. It should be noted that "ND" in the tables indicates that no measurement was performed.

[0220] Table 3

[0221]

[0222] Table 4

[0223]

[0224] <Shaping Tests and Shape Retention Tests>

[0225] As shown in Table 3, the results of both the shape retention test and the formability test of the guidewires 100 in Examples 1 to 16 are either "0" or "△". The elastic deformation power of the Ni-Ti alloy in the flat portion 11g of the guidewires 100 in Examples 1 to 16 is 46.0% to 59.5% and the martensitic hardness is 1300 N / mm². 2 Above 3000N / mm 2 The following (Condition 1).

[0226] On the other hand, as shown in Table 4, the results of either the shape retention test or the shape shaping test for the guidewires 100 of Comparative Examples 1 to 4 are “×”. The shape shaping test results for the guidewires 100 of Comparative Examples 1 and 4 are “〇”, but the shape retention test results are “×”. The Martens hardness of the guidewire 100 of Comparative Example 1 is greater than the upper limit of Condition 1, and it is harder than Examples 1 to 16, therefore it is presumed that it cannot be formed. The elastic deformation power of the guidewire 100 of Comparative Example 4 is greater than the upper limit of Condition 1, and it is more hyperelastic than Examples 1 to 16, therefore it is presumed that it cannot be formed. In addition, as shown in Table 4, the shape retention test results for the guidewires 100 of Comparative Examples 2 and 3 are “〇”, but the shape shaping test results are “×”. The Martens hardness of the guidewire 100 of Comparative Example 2 is less than the lower limit of Condition 1, and it is softer than Examples 1 to 16, therefore it is presumed that it is prone to plastic deformation. The elastic deformation power of the guide wire 100 in Comparative Example 3 is smaller than the lower limit value of Condition 1, and its hyperelasticity is lower compared with Examples 1 to 16. Therefore, it is presumed that plastic deformation occurs.

[0227] As described above, the flat plate portion 11g, formed from a Ni-Ti alloy that satisfies condition 1 above, has both shaping properties and shape retention.

[0228] Furthermore, as shown in Table 3, the results of the shaping tests for guide wires 100 in Examples 1 to 3 were "△", while the results of the shaping tests for guide wires 100 in Examples 4 to 16 were "〇". The elastic deformation power of the 11g Ni-Ti alloy in the flat portion of the guide wires 100 in Examples 4 to 16 was 46.0% to 59.5%, and the Martens hardness was 1300 N / mm. 2 The above is 2120 N / mm 2 The following (condition 2). The Martens hardness of the guide wires 100 in Examples 1 to 3 is greater than the upper limit of condition 2. Therefore, compared with the guide wires 100 in Examples 4 to 16, they are harder and presumably difficult to form.

[0229] As described above, the guide wire 100 formed from the Ni-Ti alloy that satisfies condition 2 above is superior in both shape retention and shape-forming properties.

[0230] <Sagging Resistance Test>

[0231] As shown in Table 3, the results of the anti-sagging test for guidewires 100 in Examples 1, 3-4, 6-8, and 11-16 are either "0" or "△". On the other hand, the results of the anti-sagging test for guidewires 100 in Examples 9 and 10 are "×". The proportion (heat treatment ratio) of the length along the long axis from the front end of the transition portion 11f to the base end of the heat treatment region H of guidewires 100 in Examples 1, 3-4, 6-8, and 11-16 in the length along the long axis of the transition portion 11f is 10% or more and 100% or less (condition 3). In contrast, the heat treatment ratio of guidewires 100 in Examples 9 and 10 is smaller than the lower limit of condition 3, and heat treatment is performed only on a portion of the flat plate portion 11g or a very small portion of the flat plate portion 11g and the front end side of the transition portion 11f. Therefore, as Figure 4B As shown, the guidewire 100 of Examples 9 and 10 exhibits a sharp change in rigidity near the boundary between the flat plate portion 11g and the transition portion 11f, presumably indicating a decrease in resistance to sagging.

[0232] Furthermore, as shown in Table 3, the results of the sag resistance test for guidewires 100 in Examples 4, 6 to 8 are "0". On the other hand, for example, the results of the sag resistance test for guidewires 100 in Examples 12 and 13 are "△". In Examples 4, 6 to 8, the proportion of the length along the long axis of guidewires 100 from the front end of the transition portion 11f to the base end of the heat-treated region H in the long axis direction is 55% to 65% (condition 4). In contrast, the heat treatment ratio of guidewire 100 in Example 12 is smaller than the lower limit of condition 4, and the base end of the heat-treated region H is arranged at the front end of the transition portion 11f where the rigidity is low. Therefore, the rigidity of guidewire 100 in Example 12 changes drastically at the base end of the heat-treated region H, and it is presumed that the sag resistance is reduced. In addition, the heat treatment ratio of guidewire 100 in Example 13 is larger than the upper limit of condition 4, and the length of the portion of the transition portion 11f where the rigidity is reduced due to heat treatment is longer. Therefore, the pushing force of the guidewire 100 in Example 13 is difficult to be transmitted to the front end of the guidewire 100, and the anti-prolapse performance is presumed to be reduced.

[0233] As described above, the proportion of the length along the long axis from the front end of the transition portion 11f to the base end of the heat treatment region H in the length along the long axis of the transition portion 11f satisfies condition 3 above, and more preferably, the guide wire 100 that satisfies condition 4 above has excellent resistance to sagging.

[0234] <Twist Resistance Test>

[0235] As shown in Table 3, the results of the kink resistance test for guide wires 100 in Examples 1, 3-4, and 6-14 are "0". On the other hand, the results of the kink resistance test for guide wires 100 in Examples 15 and 16 are "×". The proportion of the length along the long axis of guide wires 100 from the front end of transition portion 11f to the base end of heat treatment region H in the long axis direction of transition portion 11f in Examples 1, 3-4, and 6-14 is 10% to 100% (Condition 3). In contrast, the heat treatment ratio in Examples 15 and 16 is greater than the upper limit of Condition 3, and heat treatment is performed up to the part that has not undergone cold working. Since the core component 10 is made of Ni-Ti alloy, if heat treatment is performed on the part that has not undergone cold working, the superelasticity decreases, making it prone to plastic deformation. Therefore, it is presumed that the kink resistance of guide wires 100 in Examples 15 and 16 is reduced.

[0236] As described above, the guide wire 100 with a heat treatment ratio of transition section 11f that satisfies condition 3 above has excellent kink resistance.

[0237] This application is based on Japanese Patent Application No. 2020-183259, filed on October 30, 2020, the disclosure of which is incorporated herein by reference in its entirety.

[0238] Explanation of reference numerals in the attached figures

[0239] 10-core components

[0240] 11 First core portion (11a First joint portion, 11b First outer diameter constant portion, 11c First tapered portion, 11d Second outer diameter constant portion, 11e Second tapered portion, 11f Transition portion, 11g Flat plate portion)

[0241] 12 Second core (12a base, 12b second joint)

[0242] 13 mating surfaces

[0243] 20 lumen body,

[0244] 21. First coil

[0245] 22. Second coil

[0246] 30 fixed parts

[0247] 31. Front-end fixing part

[0248] 32 Intermediate fixing part (32a Cylindrical component), 33 Base end fixing part,

[0249] 40 layers of coating

[0250] 41 First covering layer,

[0251] 42 Second Covering Layer

[0252] 43 Third covering layer

[0253] 100 guidewire, C central axis, H heat treatment zone.

Claims

1. A guidewire, which has a long core component with a flat section at its tip. The flat plate portion has an elastic deformation power of 46.0% to 59.5% and a Martens hardness of 1300 N / mm². 2 Above 3000N / mm 2 The following Ni-Ti alloy is formed.

2. The guidewire as described in claim 1, wherein, The Martens hardness is 1300 N / mm. 2 The above is 2120 N / mm 2 the following.

3. The guidewire as described in claim 1 or 2, wherein, The core component, starting from the front end, sequentially includes the flat plate portion and a transition portion extending from the base end of the flat plate portion along the long axis toward the base end side. The core component has a heat-treated area extending from the front end of the flat plate portion to at least a portion of the transition portion.

4. The guidewire as described in claim 3, wherein, The length along the long axis from the front end of the transition section to the base end of the heat treatment region accounts for more than 10% and less than 100% of the total length along the long axis of the transition section.

5. The guidewire as described in claim 4, wherein, The length along the long axis from the front end of the transition section to the base end of the heat treatment region accounts for more than 55% and less than 65% of the total length along the long axis of the transition section.

6. A method for manufacturing a guidewire, wherein the method comprises: A process of cold-working the front end of the core component in such a way that it has a flat plate portion and a transition portion extending from the base end of the flat plate portion along the long axis towards the base end side; and With an elastic deformation power of 46.0% to 59.5% and a martensitic hardness of 1300 N / mm², 2 Above 3000N / mm 2 The following is a process of heat-treating at least a portion of the flat plate portion and the transition portion.

Images