Guide wire and method for manufacturing a guide wire

Abstract

[Problem] To provide a guide wire and a guide wire production method, whereby a procedure can be easily performed while maintaining high operability and blood vessel selectivity, as a result of the guide wire having: shaping properties whereby a desired shaped can be shaped; and shape-holding properties whereby the shape that has been shaped can be held inside the blood vessel, against external forces acting thereupon. [Solution] A guide wire 100 that comprises a long core member 10 having a flat section 11g at the tip thereof. The flat section 11g is formed using a Ni-Ti alloy that has an elastic deformation power of 46.0%–59.5% and a Martens hardness of 1,300 N / mm2– 3,000N / mm2 or, ideally, a Martens hardness of 1,300 N / mm2–2,120 N / mm2.

Description

Technical Field

[0001] The present invention relates to a guide wire and a method for manufacturing the guide wire.

Background Art

[0002] A guide wire is a medical device used to guide various catheters for treating stenoses that occur in blood vessels such as coronary arteries to the stenoses.

[0003] The guide wire needs to advance through complex curved and branched portions of blood vessels and pass through the stenosis. Therefore, the tip of the guide wire is required to have flexibility, resilience against external forces, and kink resistance. To satisfy these requirements, the tip of the guide wire is formed of a superelastic alloy such as a Ni-Ti alloy.

[0004] By the way, before inserting the guide wire into a blood vessel, an operator may shape (shape) the tip of the guide wire for the purpose of improving the operability of the guide wire in the blood vessel and the blood vessel selectivity at the branched portion. Therefore, it is preferable that the tip of the guide wire can be easily shaped. However, in a guide wire having a tip formed of a superelastic alloy, if the superelasticity is high, even when an operator applies an external force for shaping, when the external force is removed, it returns to the shape before shaping, and it is difficult for the operator to give a desired shape.

[0005] Patent Document 1 below discloses a technique for reducing superelasticity by performing cold working or heat treatment on the tip of a guide wire formed of a superelastic alloy, enabling shaping of the tip of the guide wire.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] However, if the superelasticity of the tip of the guide wire is reduced too much, the shape becomes difficult to restore, so the shape retention property, which is the property of maintaining the shape during shaping, decreases. The guide wire inserted into the blood vessel receives an external force when the tip hits the blood vessel wall or the stenosis. At this time, a guide wire with the superelasticity of the tip reduced too much plastically deforms into a shape different from the shape during shaping. As a result, the operability and blood vessel selectivity of the guide wire decrease. When the tip of the guide wire plastically deforms during the operation in the blood vessel, the operator has to remove the guide wire from the blood vessel, reshape it, or replace it with another guide wire, which makes the procedure complicated. As a result, the procedure time is extended, and the burden on the operator and the patient increases.

[0008] The magnitude of the external force received by the guide wire in the blood vessel is smaller than the external force applied by the operator for shaping. Therefore, the tip of the guide wire needs to have the physical property of being able to be deformed by the large force applied by the operator for shaping, but being able to restore to the shaped shape without plastic deformation by the small force applied during the procedure. That is, the tip of the guide wire needs to have both shapeability that can be shaped into a desired shape before being inserted into the blood vessel and shape retention property that can maintain the shaped shape against the external force applied in the blood vessel.

[0009] At least one embodiment of the present invention has been made in view of the above circumstances. Specifically, it is an object to provide a guide wire having shapeability that can be shaped into a desired shape and shape retention property that can maintain the shaped shape against the external force applied in the blood vessel, and a method for manufacturing the guide wire.

Means for Solving the Problems

[0010] The guide wire according to this embodiment includes a long core member having a flat plate portion at the tip, and the elastic deformation work rate of the flat plate portion is 46.0% or more and 59.5% or less, and the martensite hardness is 1300 N / mm 2 or more and 3000 N / mm 2 or less, and is made of a Ni-Ti alloy.

[0011] The method for manufacturing a guide wire according to this embodiment is a method for manufacturing a guide wire including a core member, and cold working is performed on the tip of the core member so as to have a flat plate portion and a transition portion extending from the base end of the flat plate portion along the long axis direction toward the base end side. And a step of performing heat treatment on at least a part of the flat plate portion and the transition portion so that the elastic deformation work rate is 46.0% or more and 59.5% or less, and the martensite hardness is 1300 N / mm 2 or more and 3000 N / mm 2 or less.

Advantages of the Invention

[0012] According to one embodiment of the present invention, by controlling the elastic deformation work rate and the martensite hardness at the tip of a guide wire made of a Ni-Ti alloy within a predetermined range, deformation is possible with a large force applied by an operator for shaping, but with a small force applied during the procedure, it can be restored to the shape at the time of shaping without plastic deformation. It is possible to provide a guide wire having physical properties. That is, according to one embodiment of the present invention, it is possible to provide a guide wire having both shapeability and shape retention. As a result, the guide wire can be shaped by an operator and can be restored to the shape at the time of shaping even when it receives an external force that can deform the tip within a blood vessel. Therefore, the guide wire can maintain the high operability and blood vessel selectivity imparted by shaping during the procedure. In addition, since the operator does not need to remove the guide wire from the blood vessel, reshape it, or replace it with another guide wire, the procedure can be performed simply. As a result, the procedure time is shortened, so the burden on the operator and the patient can be reduced.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3A

Figure 3B

Figure 4A

Figure 4B

Figure 4C

Figure 5A

Figure 5B

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0014] Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. The embodiments shown here are examples for embodying the technical idea of the present invention and do not limit the present invention. Also, all other possible embodiments, examples, and operation techniques that can be conceived by those skilled in the art without departing from the gist of the present invention are included in the scope and gist of the present invention, and are included in the invention described in the claims and its equivalent scope.

[0015] Furthermore, the drawings attached to this specification may be schematically represented with appropriate changes in scale, aspect ratio of length and width, shape, etc. for the convenience of illustration and easy understanding, but this is merely an example and does not limit the interpretation of the present invention.

[0016] In this specification, for convenience of explanation, the direction when the guide wire 100 is in a natural state (a state where no external force is applied and it is straightly extended) is defined. In FIG. 1, the “major axis direction” is the direction in which the guide wire 100 extends, and is the direction along the central axis C of the guide wire 100 (the left - right direction in the figure). The “radial direction” is the direction of separation from or approach to the core part in the axial orthogonal cross - section (cross - section) of the core part with the major axis direction of the guide wire 100 as the reference axis. The “circumferential direction” is the rotational direction with the major axis direction of the core part as the reference axis. The “thickness direction” is the direction in which the short side of the rectangle extends in the cross - sectional view of the flat plate part 11g when the tip of the guide wire 100 has the flat plate part 11g (the front - back direction in the figure). The “width direction” is the direction in which the long side of the rectangle extends in the cross - sectional view of the flat plate part 11g when the tip of the guide wire 100 has the flat plate part 11g (the up - down direction in the figure).

[0017] Also, the side where the guide wire 100 is inserted into the blood vessel is defined as the “tip side”, and the side opposite to the tip side (the side grasped by the operator) is defined as the “base end side”. Further, a portion including a certain range along the major axis direction from the tip (the foremost end) is defined as the “tip portion”, and a portion including a certain range in the major axis direction from the base end (the most proximal end) is defined as the “base end portion”.

[0018] In the following description, when ordinal numbers such as "first" and "second" are used for explanation, unless otherwise specified, they are used for convenience only and do not define any order.

[0019] The guide wire 100 according to this embodiment is a medical device inserted into a blood vessel to guide a catheter or a stent for intravascular treatment to a stenotic portion. Note that the guide wire 100 can also be inserted into other biological lumens (blood vessels, ureters, bile ducts, fallopian tubes, hepatic ducts, etc.) other than blood vessels according to the treatment purpose and used.

[0020] [Configuration] As shown in FIG. 1 or FIG. 2, the guide wire 100 according to this embodiment has a long core member 10, a tubular body 20 that covers the periphery of the tip of the core member 10, a fixing portion 30 that fixes the tubular body 20 to the core member 10, and a coating layer 40 that covers each member including the core member 10. Hereinafter, each part of the guide wire 100 will be described in detail.

[0021] 〈Core Member〉 The core member 10 includes a first core portion 11 and a second core portion 12 that is disposed on the proximal end side of the first core portion 11 and joined to the first core portion 11.

[0022] The first core portion 11 is a long member that extends along the long axis direction from the tip of the second core portion 12 to the tip side of the guide wire 100. The first core portion 11 includes, in order from the proximal end to the tip side of the first core portion 11, a first joint portion 11a, a first constant outer diameter portion 11b, a first tapered portion 11c, a second constant outer diameter portion 11d, a second tapered portion 11e, a transition portion 11f, and a flat plate portion 11g, and each portion is integrally formed.

[0023] The first joint portion 11a is a portion that is joined to the second joint portion 12b of the second core portion 12 described later. The outer diameter of the first joint portion 11a is larger than the outer diameter of the first constant outer diameter portion 11b and is substantially equal to the outer diameter of the second joint portion 12b. The outer diameters of the first joint portion 11a and the second joint portion 12b are larger than the outer diameters of the first constant outer diameter portion 11b and the base portion 12a of the second core portion 12. That is, the area of the joint surface 13 between the first joint portion 11a and the second joint portion 12b is larger than the first constant outer diameter portion 11b and the base portion 12a. Thereby, when the guide wire 100 is bent, the stress acting on the joint surface 13 is dispersed to the first constant outer diameter portion 11b and the base portion 12a having an outer diameter smaller than that of the joint surface 13, and concentration of stress on the joint surface 13 can be suppressed. Therefore, the core member 10 can obtain high joint strength at the joint surface 13.

[0024] The first constant outer diameter portion 11b extends a predetermined length from the tip of the first joint portion 11a to the base end of the first tapered portion 11c. The outer diameter of the first constant outer diameter portion 11b is substantially constant and is substantially equal to the outer diameter of the base portion 12a of the second core portion 12.

[0025] The first tapered portion 11c extends a predetermined length from the tip 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 has a tapered shape in which the outer diameter gradually decreases from the first constant outer diameter portion 11b toward the tip side. The tapered shape of the first tapered portion 11c can be formed by performing mechanical grinding with a grindstone or etching with an acid on the first core portion 11.

[0026] The second constant outer diameter portion 11d extends a predetermined length from the tip of the first tapered portion 11c to the base end of the second tapered portion 11e. The outer diameter of the second constant outer diameter portion 11d is substantially constant and is smaller than the outer diameter of the first constant outer diameter portion 11b.

[0027] The second tapered portion 11e extends a predetermined length from the tip of the second constant outer diameter portion 11d to the base end of the transition portion 11f. The second tapered portion 11e has a tapered shape in which the outer diameter gradually decreases from the second constant outer diameter portion 11d toward the transition portion 11f. The tapered shape of the second tapered portion 11e can be formed by performing mechanical grinding with a grindstone or etching with an acid on the first core portion 11.

[0028] The transition portion 11f extends a predetermined length from the tip of the second tapered portion 11e to the base end of the flat plate portion 11g. As shown in FIG. 3A or FIG. 3B, the transition portion 11f has a wedge shape in which the thickness gradually decreases and the width gradually increases from the second tapered portion 11e toward the flat plate portion 11g. The wedge shape of the transition portion 11f can be formed by pressing the first core portion 11 having a circular cross-sectional shape, which is a type of cold working. The cross-sectional shape of the transition portion 11f in a plan view (cross-sectional view) orthogonal to the major axis direction forms a circle with an outer diameter substantially equal to that of the second tapered portion 11e on the base end side, but gradually deforms from a circle to a rectangle from the base end side toward the tip end side, and forms a rectangle substantially the same shape as the flat plate portion 11g on the tip end side. The tip end portion of the transition portion 11f has a thickness and width substantially equal to those of the base end portion of the flat plate portion 11g, and forms a surface continuous with the flat plate portion 11g. Note that the two-dot chain line in FIG. 3B is a virtual line that divides the regions of the flat plate portion 11g, the transition portion 11f, and the second tapered portion 11e. Also, the "thickness" of the flat plate portion 11g is 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 the length of the long side of the rectangle in the cross-sectional view of the flat plate portion 11g.

[0029] The flat plate portion 11g extends a predetermined length from the tip of the transition portion 11f to the tip of the guide wire 100. The flat plate portion 11g is formed by pressing a first core portion 11 having a circular cross-sectional shape. Therefore, the flat plate portion 11g has a rectangular cross-sectional shape. The thickness of the flat plate portion 11g is substantially constant from the tip of the transition portion 11f to the tip of the flat plate portion 11g. As shown in FIGS. 3A and 3B, the shape of the flat plate portion 11g viewed from the thickness direction is formed into a rectangular shape with rounded corners at the tip of the flat plate portion 11g. Therefore, the width of the flat plate portion 11g is substantially constant from the tip of the transition portion 11f toward the tip side, but becomes smaller at the rounded portion. Note that the width of the flat plate portion 11g may be constant from the tip of the transition portion 11f to the tip of the flat plate portion 11g. The cross-sectional shape of the flat plate portion 11g is not limited to a rectangle, and may be a rounded rectangle having an R shape at the corners.

[0030] Note that the structure of the first core portion 11 is not limited to the above. For example, the first core portion 11 may have a constant outer shape and a constant outer diameter from the tip to the base end.

[0031] Also, in the first core portion 11, at least the region where the flat plate portion 11g is located (preferably, at least a part of the flat plate portion 11g and the transition portion 11f) has both formability and shape retention.

[0032] The second core portion 12 is a long member extending from the base end of the first core portion 11 toward the base end side of the guide wire 100. The second core portion 12 includes a base portion 12a and a second joint portion 12b in order from the base end to the tip side of the second core portion 12, and each portion is integrally formed.

[0033] The base portion 12a extends a predetermined length from the base end of the second joint portion 12b toward the base end side of the guide wire 100. The outer diameter of the base portion 12a is substantially constant and is substantially equal to the outer diameter of the first outer diameter constant portion 11b.

[0034] The second joint portion 12b is a portion to be joined to the first joint portion 11a. The outer diameter of the second joint portion 12b is larger than the outer diameter of the base portion 12a and equal to the outer diameter of the first joint portion 11a. The first joint portion 11a and the second joint portion 12b can be joined by welding, brazing, or soldering.

[0035] Here, specific dimensional examples of the guide wire 100 will be described. The total length of the guide wire 100 in the long axis direction 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 joint portion 11a and the first constant outer diameter 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 constant outer diameter 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 plate portion 11g is 1 mm to 20 mm.

[0036] The outer diameters of the first joint portion 11a and the first constant outer diameter portion 11b are 0.2 mm to 1 mm. The outer diameters of the first tapered portion 11c and the second constant outer diameter portion 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.

[0037] The length of the second core portion 12 is 850 mm to 3500 mm. The outer diameter of the second core portion 12 is 0.2 mm to 1 mm.

[0038] The first core part 11 and the second core part 12 can be formed of various metal materials such as superelastic alloys such as Ni-Ti alloys, stainless steels such as SUS302, SUS304, SUS303, SUS316, SUS316L, SUS316J1, SUS316J1L, SUS405, SUS430, SUS434, SUS444, SUS429, SUS430F, piano wire, cobalt-based alloys, etc. Further, the first core part 11 is preferably formed of a material having a lower rigidity than the material of the second core part 12. As an example, the first core part 11 is formed of a Ni-Ti alloy, and the second core part 12 is formed of stainless steel. Note that the materials forming the first core part 11 and the second core part 12 are not limited to the above examples. Also, the first core part 11 and the second core part 12 may be formed of the same material.

[0039] Furthermore, the core member 10 may be formed of a single continuous member instead of being formed of a plurality of members such as the first core part 11 and the second core part 12.

[0040] 〈Cavity tube〉 The cavity tube 20 is a member formed by spirally winding a wire around the core member 10. In the present embodiment, the cavity tube 20 is formed of a first coil 21 and a second coil 22 disposed on the proximal end side of the first coil 21. The first coil 21 is disposed from the tip to the middle part of the first core part 11 of the core member 10. The second coil 22 is disposed from the middle part to the proximal end side of the first core part 11. Note that the cavity tube 20 may be formed of one coil. The cavity tube 20 may be formed of three or more coils.

[0041] The first coil 21 surrounds the first core part 11 of the core member 10 and is fixed to the first core part 11. The first coil 21 is coaxially disposed with the first core part 11. The length of the first coil 21 is 3 mm to 60 mm.

[0042] The first coil 21 is formed by spirally winding the wire so as to have a gap between adjacent wires. The gap between adjacent wires of the first coil 21 is 1 μm to 10 μm. The gaps between adjacent wires of the first coil 21 are preferably equally spaced.

[0043] The second coil 22 surrounds the first core portion 11 of the core member 10 and is fixed to the first core portion 11. The second coil 22 is arranged coaxially with the first core portion 11. The length of the second coil 22 is 10 mm to 400 mm.

[0044] The second coil 22 has a tightly wound portion in which the wire is spirally wound densely so that there is no gap between adjacent wires, and a loosely wound portion in which the wire is spirally wound loosely so that there is a gap between adjacent wires. In the present embodiment, the tightly wound portion in the second coil 22 is located at the tip end portion and the base end portion of the second coil 22, and the loosely wound portion is located between the tightly wound portion on the tip end side and the tightly wound portion on the base end side. Note that the second coil 22 may be composed only of the tightly wound portion without the loosely wound portion.

[0045] The base end portion of the first coil 21 and the tip end portion of the second coil 22 are partially intertwined. That is, the wires at the base end portion of the first coil 21 and the wires at the tip end portion of the second coil 22 are arranged alternately along the long axis direction. Thereby, separation between the first coil 21 and the second coil 22 is suppressed. The length at which the base end portion of the first coil 21 and the tip end portion 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 the same so that they can be intertwined.

[0046] The outer diameters of the wires of the first coil 21 and the second coil 22 are 20 μm to 90 μm, preferably 30 μm to 70 μm. In the present 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. Also, the wires forming the first coil 21 and the second coil 22 may be not only a single wire but also a stranded wire composed of two or more wires.

[0047] The wire materials of the first coil 21 and the second coil 22 are not particularly limited, but can be formed of metals such as stainless steel, superelastic alloy, cobalt-based alloy, gold, platinum, tungsten, or alloys containing these. As an example, the first coil 21 is made of a platinum-based alloy that is more flexible and has higher contrast than the second coil 22, and the material of the second coil 22 is formed of stainless steel. For the platinum-based alloy, Pt-Ir, Pt-Ni, Pt-W, etc. are preferably used.

[0048] The outer diameters of the first coil 21 and the second coil 22 are preferably constant from the tip end to the base end, respectively. In the present embodiment, the outer diameter of the first coil 21 and the outer diameter of the second coil 22 are substantially equal. Therefore, the outer diameter of the tube body 20 is substantially constant from the tip 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.

[0049] The material forming the wire material constituting the first coil 21 and the second coil 22, the outer diameter of the wire material, the cross-sectional shape of the wire material, the pitch of the wire material, etc. can be appropriately selected according to the purpose of the guide wire 100. Also, the cross-sectional shape of the wire material is preferably circular, but may be elliptical, polygonal, etc. The center of the cross-section of the wire material whose cross-sectional shape is not circular can be the center of gravity of the cross-section of the wire material.

[0050] 〈Fixing portion〉 The fixing portion 30 is a member for fixing the tube body 20 to the core member 10. In the present embodiment, the fixing portion 30 has a tip fixing portion 31 for fixing the tip end of the tube body 20 to the core member 10, an intermediate fixing portion 32 for fixing the intermediate portion of the tube body 20 to the core member 10, and a base end fixing portion 33 for fixing the base end of the tube body 20 to the core member 10.

[0051] The material forming the fixing portion 30 is a brazing material or a soldering material. Examples of the brazing material include gold brazing and silver brazing. Examples of the soldering material include Sn-Ag alloy solder and Sn-Pb alloy solder. The material forming the fixing portion 30 may be an adhesive.

[0052] The tip fixing portion 31 fixes the tip portion of the first coil 21 to the flat plate portion 11g of the first core portion 11. The tip fixing portion 31 is located at the foremost end of the guide wire 100, and its outer surface is smoothly formed in a substantially hemispherical shape.

[0053] The intermediate fixing portion 32 fixes the base end portion of the first coil 21 and the tip portion of the second coil 22 to the second tapered portion 11e of the first core portion 11 via the cylindrical member 32a. The intermediate fixing portion 32 is provided at a position where the base end portion of the first coil 21 and the tip portion of the second coil 22 are intertwined in the first core portion 11.

[0054] The cylindrical member 32a is disposed between the inner peripheral surface of the tube cavity 20 and the outer peripheral surface of the core member 10. The cylindrical member 32a fixes the tube cavity 20 and the core member 10 coaxially by reducing the gap between the inner peripheral surface of the tube cavity 20 and the outer peripheral surface of the core member 10. In the present embodiment, the outer diameter of the tip portion of the cylindrical member 32a is smaller than the outer diameter of the base end portion of the cylindrical member 32a. Thereby, as shown in FIG. 2, the first coil 21 with a small inner diameter and the second coil 22 with a large inner diameter can be fixed coaxially with respect to the core member 10. The outer diameter of the tip portion of the cylindrical member 32a and the outer diameter of the base end portion of the cylindrical member 32a may 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 a metal or a resin material. Note that the guide wire 100 may not include the cylindrical member 32a.

[0055] The base end fixing portion 33 fixes the base end portion of the second coil 22 to the second constant outer diameter portion 11d of the first core portion 11.

[0056] 〈Coating layer〉 The coating layer 40 includes a first coating layer 41, a second coating layer 42, and a third coating layer 43. The coating layer 40 can be formed of a material that can reduce the friction generated between the guide wire 100 and a blood vessel or a catheter. Thereby, the coating layer 40 improves the operability and safety of the guide wire 100.

[0057] The first coating layer 41 covers the outer surfaces of the respective parts (the tube cavity part 20 and the fixing part 30) provided in the first core part 11 and a part of the first core part 11 (the second constant outer diameter part 11d).

[0058] The second coating layer 42 covers the part of the core member 10 located on the proximal end side of the tube cavity part 20. The second coating layer 42 covers the proximal end part of the first core part 11 (the first tapered part 11c and the first constant outer diameter part 11b) and the outer surface of the second core part 12. That is, the second coating layer 42 is coated on the part of the core member 10 located on the proximal end side of the tube cavity part 20, excluding the first joint part 11a and the second joint part 12b.

[0059] The third coating layer 43 covers the outer surfaces of the first joint part 11a and the second joint part 12b.

[0060] Note that the second coating layer 42 may cover the entire part of the core member 10 located on the proximal end side of the tube cavity part 20. In that case, the third coating layer 43 is not provided. Alternatively, the second coating layer 42 may not cover a part of the part of the core member 10 located on the proximal end side of the tube cavity part 20. In that case, the third coating layer 43 can also be provided on the part not covered by the second coating layer 42.

[0061] The first coating layer 41 can be formed of a hydrophilic polymer. The hydrophilic polymer forming the first coating layer 41 includes cellulose-based polymer substances, polyethylene oxide-based polymer substances, maleic anhydride-based polymer substances (for example, maleic anhydride copolymers such as methyl vinyl ether-maleic anhydride copolymers), acrylamide-based polymer substances (for example, polyacrylamide, block copolymers of glycidyl methacrylate-dimethylacrylamide), water-soluble nylon, polyvinyl alcohol, polyvinyl pyrrolidone, and derivatives thereof.

[0062] The second coating layer 42 and the third coating layer 43 can be made of a low-friction material. Examples of low-friction materials include polyolefins such as polyethylene and polypropylene, polyvinyl chloride, polyesters (such as PET and PBT), polyamides, polyimides, polyurethanes, polystyrenes, polycarbonates, silicone resins, fluorine-based resins (such as PTFE and ETFE), or composite materials thereof.

[0063] Note 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 above. The first coating layer 41, the second coating layer 42, and the third coating layer 43 may be formed of different materials along the long axis direction of the core member 10, respectively. For example, the material covering the tip of the first core portion 11 and the material covering the base end portion of the first core portion 11 of the second coating layer 42 may be different. Also, the number of layers of each of the first coating layer 41, the second coating layer 42, and the third coating layer 43 may be plural. Note that any one of the first coating layer 41, the second coating layer 42, and the third coating layer 43 may not be provided.

[0064] The tip of the guide wire 100 according to the present embodiment has both shapeability and shape retention. Shapeability is the property that enables the operator to shape the tip of the guide wire 100. The guide wire 100 is shaped to give the tip a desired shape, thereby improving the operability of the guide wire 100 in the blood vessel and the blood vessel selectivity at the branch portion. The shape imparted to the guide wire 100 by shaping depends on the inner diameter and shape of the patient's blood vessel. Therefore, it is preferable that the guide wire 100 can be easily shaped into a desired shape. That is, excellent shapeability is required.

[0065] Shape retention refers to the property that the shape imparted by the operator to the tip of the guide wire 100 by shaping is maintained during the operation of the guide wire 100 within the blood vessel. Generally, the shape imparted to the guide wire 100 by shaping is a curved shape, and its radius of curvature is large relative to the inner diameter of the blood vessel. Therefore, the guide wire 100 deforms according to the inner diameter and shape of the blood vessel. In addition, the guide wire 100 may accidentally bend into a U shape when the tip hits the blood vessel wall at the branch or gets caught on the stent. Furthermore, the guide wire 100 may also be intentionally bent into a U shape for the purpose of preventing blood vessel perforation when passing through the stenosis. Thus, the tip of the guide wire 100 is subjected to an external force that can deform the tip during the operation within the blood vessel. If the resilience of the guide wire 100 against the external force is low, the guide wire 100 undergoes plastic deformation and cannot maintain the shape imparted by the operator's shaping, resulting in a decrease in operability and blood vessel selectivity. When the tip of the guide wire deforms, the operator needs to remove the guide wire from the blood vessel and reshape it. If the deformation is so severe that it is difficult to reshape, it is necessary to replace it with another guide wire. This prolongs the procedure time and increases the burden on the operator and the patient. Therefore, it is preferable that the guide wire 100 has resilience such that it can return to the shape imparted by the operator's shaping once the external force is removed even if it is deformed by the external force during the operation within the blood vessel. That is, the guide wire 100 is required to have excellent shape retention.

[0066] The guide wire 100 having both shapeability and shape retention can be obtained by controlling the elastic deformation work rate and the martensite hardness of the tip of the guide wire 100 formed of a Ni-Ti alloy within a predetermined range.

[0067] The elastic deformation work rate and the martensite hardness are calculated from the load-displacement curve obtained in the instrumented indentation hardness test on the flat portion 11g of the guide wire 100. The elastic deformation work rate is the ratio of the work amount of elastic deformation to the total work amount (the sum of the work amount of plastic deformation and the work amount of elastic deformation). The martensite hardness is the value obtained by dividing the test load by the surface area into which the indenter has penetrated in the instrumented indentation hardness test.

[0068] A material with a high elastic deformation work rate has a high shape recovery property due to superelasticity. Therefore, the flat portion 11g of the guide wire 100 formed of a material with a high elastic deformation work rate is likely to return to its original shape when the external force is removed even if an external force is applied. Thus, the higher the elastic deformation work rate, the lower the shape formability and the higher the shape retention of the flat portion 11g. On the other hand, a material with a low elastic deformation work rate is likely to undergo plastic deformation. Therefore, the flat portion 11g formed of a material with a low elastic deformation work rate undergoes plastic deformation when an external force is applied and is likely to maintain its shape even when the external force is removed. Thus, the lower the elastic deformation work rate, the higher the shape formability of the flat portion 11g, but the lower the shape retention.

[0069] A material with a large martensite hardness is hard. Therefore, the flat portion 11g of the guide wire 100 formed of a material with a large martensite hardness is less likely to deform under an external force. Thus, the larger the martensite hardness, the lower the shape formability and the higher the shape retention of the flat portion 11g. On the other hand, the flat portion 11g of the guide wire 100 formed of a material with a small martensite hardness is likely to undergo plastic deformation even with a small external force received in the blood vessel. Thus, the smaller the martensite hardness, the higher the shape formability and the lower the shape retention of the flat portion 11g.

[0070] The magnitude of the external force received by the guide wire 100 in the blood vessel is smaller than the external force applied by the operator for shaping. For this reason, the tip of the guide wire 100 can be deformed by a large force applied by the operator for shaping, but by having physical properties that can be restored to the shape at the time of shaping without undergoing plastic deformation by a small force applied during the procedure, it is possible to have both shape formability and shape retention.

[0071] The influence degree on shapeability and shape retention is such that the martensite hardness is greater than the elastic deformation work rate. Therefore, even if only the elastic deformation work rate is controlled, it is not possible to improve both shapeability and shape retention, and it is particularly necessary to appropriately control the martensite hardness.

[0072] The flat plate portion 11g of the guide wire 100 according to the present embodiment has an elastic deformation work rate of 46.0% to 59.5% and a martensite hardness of 1300 N / mm 2 ~3000 N / mm 2 and is formed of a Ni-Ti alloy.

[0073] The tip of the guide wire 100 in which the flat plate portion 11g has the elastic deformation work rate and martensite hardness within the above ranges can be deformed by a large force applied by the operator for shaping, but can be restored to the shape at the time of shaping without plastic deformation by a small force applied during the procedure. Thereby, the guide wire 100 can be shaped by the operator and can be restored to the shape at the time of shaping even when receiving an external force such that the tip can be deformed within the blood vessel. Therefore, the guide wire can maintain the high operability and blood vessel selectivity imparted by shaping also during the procedure. Further, since the operator does not need to remove the guide wire 100 from the blood vessel, reshape it, or replace it with another guide wire, the procedure can be performed simply. As a result, the procedure time is shortened, so the burden on the operator and the patient can be reduced.

[0074] Further, the flat plate portion 11g of the guide wire 100 preferably has an elastic deformation work rate of 46.0% to 59.5% and a martensite hardness of 1300 N / mm 2 ~2120 N / mm 2 The flat plate portion 11g of the guide wire 100 has the elastic deformation work rate in the range of 46.0% to 59.5%, and then the martensite hardness is 1300 N / mm 2 ~2120 N / mm 2By setting it within the range, the flat plate portion 11g of the first core portion 11 becomes even more flexible, thus further improving the formability.

[0075] Also, in order for the guide wire 100 to have the elastic deformation work rate and martensite hardness of the flat plate portion 11g within the above range, it is preferable that the tip of the core member 10 is heat-treated.

[0076] The flat plate portion 11g is formed by pressing the tip of the first core portion 11 made of Ni-Ti alloy. The flat plate portion 11g after pressing has a reduced superelasticity compared to the Ni-Ti alloy before pressing due to the strain introduced by the processing. Therefore, the flat plate portion 11g after pressing has a low elastic deformation work rate and thus low shape retention. By heat-treating the flat plate portion 11g after pressing, the strain is removed and the superelasticity is improved. As a result, the flat plate portion 11g has a high elastic deformation work rate and improved shape retention. Also, the flat plate portion 11g after pressing is harder due to work hardening compared to the Ni-Ti alloy before pressing. Therefore, the flat plate portion 11g after pressing has a large martensite hardness and thus low formability. By heat-treating the flat plate portion 11g after pressing, the flat plate portion 11g becomes softer. As a result, the flat plate portion 11g has a small martensite hardness and improved formability. In this way, the guide wire 100 can control the elastic deformation work rate and martensite hardness of the tip of the guide wire 100 formed of Ni-Ti alloy within a predetermined range by heat-treating the pressed flat plate portion 11g. Thereby, the guide wire 100 can have both formability and shape retention.

[0077] The heat treatment is preferably performed on at least a part 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 the present embodiment has a heat treatment region H that continuously extends from the tip of the flat plate portion 11g to at least a part of the transition portion 11f along the major axis direction. One end of the heat treatment region H of the guide wire 100 coincides with the tip 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 a region where an oxide film is formed on at least a part of the circumferential direction of the outer surface of the first core member by the heat treatment. Therefore, an oxide film is formed on the outer surface of the guide wire 100 from the tip of the flat plate portion 11g to at least a part of the transition portion 11f along the major axis direction. Further, in this specification, the total length from one end to the other end of the heat treatment region H along the major axis direction of the guide wire 100 is referred to as the heat treatment length. The heat treatment length of the guide wire 100 is longer than the length along the major axis direction of the flat plate portion 11g.

[0078] The guide wire 100 has a heat treatment region H that continuously extends from the tip of the flat plate portion 11g to at least a part of the transition portion 11f, thereby suppressing a sudden change in rigidity along the major axis direction of the guide wire 100. FIGS. 4A to 4C are diagrams schematically showing the rigidity of the tip portion of the first core portion 11 when the guide wire 100 is heat-treated. In FIGS. 4A and 4C, the point groups appearing on the outer surface of the first core portion 11 represent the high and low rigidity. The denser the points, the lower the rigidity, and the sparser the points, the higher the rigidity. The two-dot chain lines in FIGS. 4A to 4C are virtual lines that divide the regions of the flat plate portion 11g, the transition portion 11f, and the second tapered portion 11e. As shown in FIG. 4A, in the guide wire 100, the flat plate portion 11g has a flat plate shape with a small thickness. Therefore, the rigidity of the flat plate portion 11g is low and constant along the major axis direction. On the other hand, the transition portion 11f has a wedge shape in which the thickness gradually increases and the width gradually decreases from the flat plate portion 11g toward 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 tip and gradually increases from the tip toward the base end. Here, when the first core portion 11 is heat-treated, the rigidity of the heat-treated portion of the first core portion 11 decreases. Therefore, as shown in FIG. 4B, when only a part of the flat plate portion 11g is heat-treated, a sudden change in rigidity occurs in the flat plate portion 11g at the position of the base end of the heat treatment region H. Alternatively, when only the flat plate portion 11g is heat-treated, a sudden change in rigidity occurs at the boundary between the flat plate portion 11g and the transition portion 11f in the first core portion 11. The guide wire 100 is likely to bend at a point where the rigidity changes suddenly along the major axis direction, and prolapse is likely to occur. In the present embodiment, as shown in FIG. 4C, it is preferable that the flat plate portion 11g is heat-treated over the entire length, and in addition, a part of the transition portion 11f is also heat-treated. Thereby, the sudden change in rigidity along the major axis direction of the guide wire 100 is suppressed, and the anti-prolapse property is improved.

[0079] Note that prolapse means a state in which, with the tip of the guide wire 100 inserted from the main trunk to the side branch, the portion on the proximal side of the tip of the guide wire 100 is locally bent, and the bent portion deviates to the distal side of the branch from the main trunk to the side branch. When the guide wire 100 is in such a state, the pushing force and torque applied to the proximal end of the guide wire 100 are transmitted only to the bent portion. Therefore, it becomes difficult for the operator to advance the tip of the guide wire 100 to the tip of the side branch. In addition, since the tip of the catheter that can be advanced along the guide wire 100 is guided to the bent portion, it becomes difficult for the operator to advance the catheter to the side branch.

[0080] The proximal end of the heat treatment region H of the guide wire 100 is preferably located at the transition portion 11f. That is, the proximal end of the heat treatment region H of the guide wire 100 is preferably not located in the second tapered portion 11e. When the second tapered portion 11e that has not been cold-worked is heat-treated, the superelasticity decreases and it becomes easy to plastically deform. As a result, the guide wire 100 is likely to kink in the blood vessel. In the present embodiment, as shown in FIG. 4C, only the cold-worked flat plate portion 11g and the transition portion 11f are heat-treated. Thereby, the guide wire 100 is suppressed from plastically deforming due to a decrease in superelasticity, and the kink resistance is improved.

[0081] The guide wire 100 preferably has a ratio of the length along the major axis from the tip of the transition portion 11f to the base end of the heat treatment region H to the length along the major axis of the transition portion 11f in the major axis direction of the transition portion 11f of 10% or more and 100% or less. Thereby, the guide wire 100 can improve the anti-prolapse property and the anti-kink property while having shape formability and shape retention. When the heat treatment length is longer than the above range, the first core portion 11 is heat treated at a portion that is not cold worked like the second tapered portion 11e. When the first core portion 11 is heat treated at a portion that is not cold worked, the superelasticity decreases and plastic deformation easily occurs. As a result, the guide wire 100 is likely to kink in the blood vessel. Further, when the heat treatment length is shorter than the above range and only the flat plate portion 11g is heat treated, a sudden change in rigidity occurs in the first core portion 11 or at the boundary between the flat plate portion 11g and the transition portion 11f, and prolapse is likely to occur.

[0082] It is more preferable that the ratio of the length along the major axis direction from the tip of the transition portion 11f to the base end of the heat treatment region H to the length along the major axis direction of the transition portion 11f occupies 55% or more and 65% or less of the length along the major axis direction of the transition portion 11f. Thereby, the guide wire 100 can further improve the shapeability and shape retention while further improving the anti-prolapse property and anti-kink property. When the length along the major axis direction from the tip of the transition portion 11f to the base end of the heat treatment region H exceeds 65% of the length along the major axis direction of the transition portion 11f, the length of the portion of the transition portion 11f with reduced rigidity due to heat treatment becomes longer. Therefore, when the guide wire 100 is pushed in with the tip of the guide wire 100 inserted from the main stem to the side branch, the pushing force does not reach the tip of the guide wire 100 and the guide wire 100 bends at the transition portion 11f located in the main stem, and prolapse is likely to occur. On the other hand, when the length along the major axis direction from the tip of the transition portion 11f to the base end of the heat treatment region H is less than 55% of the length along the major axis direction of the transition portion 11f, the length of the portion of the transition portion 11f with high rigidity becomes longer. In addition, since the base end of the heat treatment region H is arranged at the tip of the transition portion 11f with low rigidity, the rigidity of the guide wire 100 changes abruptly at the base end of the heat treatment region H, and prolapse is likely to occur. By setting the length along the major axis direction from the tip of the transition portion 11f to the base end of the heat treatment region H in the heat treatment region H to 55% or more and 65% or less of the length along the major axis direction of the transition portion 11f, the guide wire 100 can further improve the anti-prolapse property and anti-kink property.

[0083] Various conditions for performing heat treatment on the tip of the core member 10 can be set as appropriate. For example, the temperature for performing heat treatment is in the range of 300°C to 650°C, and the time is in the range of 3 to 60 minutes.

[0084] The heat treatment has the effect of softening the flat portion 11g hardened by cold working to make it easily deformable, and the effect of removing the strain from the flat portion 11g whose superelasticity has decreased due to the strain introduced by cold working and moderately improving the superelasticity. Therefore, the heat treatment is particularly effective as a method for imparting formability and shape retention to the guide wire 100. Note that the method for imparting formability and shape retention to the tip of the core member 10 is not limited to heat treatment, and other methods may be applied as long as the elastic deformation work rate and the martensite hardness can be within the above ranges.

[0085] [Function and Effect] As described above, the guide wire 100 according to the present embodiment includes a long core member 10 having a flat portion 11g at the tip. The flat portion 11g has an elastic deformation work rate of 46.0% or more and 59.5% or less, and a martensite hardness of 1300 N / mm 2 or more and 3000 N / mm 2 or less, and is made of a Ni-Ti alloy.

[0086] With such a configuration, the guide wire 100 can be deformed by a large force applied by the operator for shaping, but has physical properties that can be restored to the shape during shaping without plastic deformation by a small force applied during the procedure. That is, the guide wire 100 can have both formability and shape retention. Thereby, the guide wire 100 can be shaped by the operator and can be restored to the shape during shaping even when it receives an external force that can deform the tip portion within the blood vessel. Therefore, the guide wire 100 can maintain the high operability and vessel selectivity imparted by shaping during the procedure. In addition, since the operator does not need to remove the guide wire 100 from the blood vessel, re-shape it, or replace it with another guide wire, the procedure can be performed simply. As a result, the procedure time is shortened, so the burden on the operator and the patient can be reduced.

[0087] Further, the guide wire 100 according to the present embodiment has a martensite hardness of 1300 N / mm 2 or more and 2120 N / mm2 It may be configured as follows.

[0088] With such a configuration, the guide wire 100 has improved formability because the flat plate portion 11g of the first core portion 11 at the tip of the core member 10 becomes even more flexible.

[0089] Further, the core member 10 of the guide wire 100 according to the present embodiment has, in order from the tip side, a flat plate portion 11g and a transition portion 11f extending from the base end of the flat plate portion 11g along the major axis direction toward the base end side, and the core member 10 may be configured to have a heat treatment region H extending from the tip of the flat plate portion 11g to at least a part of the transition portion 11f.

[0090] With such a configuration, the first core portion 11 can suppress a sudden change in rigidity along the major axis direction at the base end of the heat treatment region H, so that it can improve prolapse resistance and kink resistance while having formability and shape retention.

[0091] Further, for the guide wire 100 according to the present embodiment, the ratio of the length along the major axis direction from the tip of the transition portion 11f to the base end of the heat treatment region H to the length along the major axis direction of the transition portion 11f may be 10% or more and 100% or less.

[0092] With such a configuration, the guide wire 100 can improve prolapse resistance and kink resistance while having formability and shape retention.

[0093] Further, for the guide wire 100 according to the present embodiment, the ratio of the length along the major axis direction from the tip of the transition portion 11f to the base end of the heat treatment region H to the length along the major axis direction of the transition portion 11f may be 55% or more and 65% or less.

[0094] With such a configuration, the guide wire 100 can further suppress a sudden change in rigidity along the major axis direction of the guide wire 100, so that it can further improve prolapse resistance and kink resistance.

[0095] In addition, the manufacturing method of the guide wire 100 according to the present embodiment includes a core member 10, and a cold working step of forming a flat plate portion 11g and a transition portion 11f extending from the base end of the flat plate portion 11g along the major axis direction toward the base end side with respect to the tip end portion of the core member 10, and at least a part of the flat plate portion 11g and the transition portion 11f is subjected to heat treatment so that the elastic deformation work rate is 46.0% or more and 59.5% or less, and the martensite hardness is 1300 N / mm 2 or more and 3000 N / mm 2 or less.

[0096] The guide wire 100 manufactured by the above method can be deformed by a large force applied by an operator for shaping, but can have physical properties that can be restored to the shape at the time of shaping without plastic deformation by a small force applied during the procedure. That is, the guide wire 100 can have both shapeability and shape retention. Thereby, the guide wire 100 can be shaped by an operator and can be restored to the shape at the time of shaping even when it receives an external force that can deform the tip end portion within a blood vessel. Therefore, the guide wire 100 can maintain the high operability and blood vessel selectivity imparted by shaping also during the procedure. In addition, since the operator does not need to remove the guide wire 100 from the blood vessel and reshape it or replace it with another guide wire, the procedure can be performed simply. As a result, the procedure time is shortened, so the burden on the operator and the patient can be reduced. In addition, the heat treatment has the effect of softening the flat plate portion 11g hardened by cold working to make it easier to deform, and the effect of removing the strain from the flat plate portion 11g whose superelasticity has decreased due to the strain introduced by cold working and improving the superelasticity moderately. Therefore, the heat treatment is particularly effective as a method for imparting shapeability and shape retention to the guide wire 100.

Example

[0097] Hereinafter, the present invention will be specifically described by way of examples, but the scope of the present invention is not limited to the following examples.

[0098] The "manufacture of the guide wire", "evaluation method", and "evaluation results" of the guide wire 100 in the following 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. Note that the "heat treatment ratio" in Tables 1 and 2 is the ratio of the length along the major axis from the tip of the transition portion 11f to the base end of the heat treatment region H to the length along the major axis of the transition portion 11f.

[0099] [Table 1]

[0100] [Table 2]

[0101] [Manufacture of the Guide Wire] The manufacture of the guide wire 100 according to the following Examples and Comparative Examples will be described. In each of the Examples and Comparative Examples, the heat treatment performed in Step 3 was carried out in the temperature range of 300°C to 650°C and the time range of 3 minutes to 60 minutes.

[0102] <Example 1> (Step 1) Taper processing was performed on the tip of the first core portion 11 made of Ni-Ti alloy (Ni content: 54 mass% to 57 mass%) such that the outer diameter gradually decreased from the base end side to the tip end side. The outer diameter of the foremost end was 80 μm. (Step 2) A range of 16 mm from the tip of the first core portion 11 toward the base end side was pressed to form a flat plate portion 11g and a transition portion 11f. At this time, a range of 9 mm from the tip of the guide wire 100 toward the base end side was made into the flat plate portion 11g, which was formed into a flat plate shape with a constant thickness of 27 μm. A range of 7 mm from the base end of the flat plate portion 11g toward the base end side was made into the transition portion 11f, which was formed into a wedge shape with an increasing thickness toward the base end side. (Step 3) Heat treatment was performed on a range of 12.5 mm from the tip to the base end side of the first core part 11 pressed in Process 2. (Process 4) A tube cavity body 20 composed of a first coil 21 and a second coil 22 was arranged around a part of the second outer diameter constant part 11d from the flat plate part 11g of the first core part 11. The first coil 21 used a coil with a length of 28 mm to 32 mm formed by winding a wire made of a platinum-based alloy (outer diameter: 0.340 mm to 0.350 mm, wire diameter: 58 μm to 60 μm). The second coil 22 used a coil with a length of 210 mm to 220 mm formed by winding a wire made of stainless steel (outer diameter: 0.340 mm to 0.350 mm, wire diameter: 38 μm to 40 μm). The tip of the first coil 21 was fixed to the flat plate part 11g of the first core part 11 with silver solder. The base end of the first coil 21 and the tip of the second coil 22 were fixed to the second tapered part 11e of the first core part 11 with Sn-Ag alloy solder via a metal cylindrical member 32a. The base end of the second coil 22 was fixed to the second outer diameter constant part 11d of the first core part 11 with Sn-Ag alloy solder. (Process 5) The first core part 11 and the second core part 12 were joined by butt resistance welding. (Process 6) The outer surfaces of a part of the first coil 21, the second coil 22, and the second outer diameter constant part 11d were coated with a hydrophilic polymer to form a first coating layer 41. The outer surfaces of the first outer diameter constant part 11b, the first tapered part 11c of the first core part 11, and the second core part 12 were coated with a fluororesin to form a second coating layer 42. The outer surfaces of the first joint part 11a and the second joint part 12b were coated with a silicone resin to form a third coating layer 43.

[0103] The guide wires of Examples 2 to 16 were manufactured as follows. Note that the guide wires of Examples 2 to 6 and 9 to 16 were manufactured in the same manner as Example 1 for Processes 1, 2, 4 to 6, and Process 3 was manufactured as follows.

[0104] 〈Example 2〉 In Process 3, heat treatment was performed on a range of 13.0 mm from the tip to the base end side of the first core part 11 pressed in Process 2.

[0105] <Example 3> In Step 3, heat treatment was performed on a range of 13.8 mm from the leading end to the base end side of the first core portion 11 pressed in Step 2.

[0106] <Example 4> In Step 3, heat treatment was performed on a range of 13.6 mm from the leading end to the base end side of the first core portion 11 pressed in Step 2.

[0107] <Example 5> In Step 3, heat treatment was performed on a range of 12.8 mm from the leading end to the base end side of the first core portion 11 pressed in Step 2.

[0108] <Example 6> In Step 3, heat treatment was performed on a range of 13.3 mm from the leading end to the base end side of the first core portion 11 pressed in Step 2.

[0109] <Example 9> In Step 3, heat treatment was performed on a range of 7.2 mm from the leading end to the base end side of the first core portion 11 pressed in Step 2.

[0110] <Example 10> In Step 3, heat treatment was performed on a range of 9.3 mm from the leading end to the base end side of the first core portion 11 pressed in Step 2.

[0111] <Example 11> In Step 3, heat treatment was performed on a range of 10.3 mm from the leading end to the base end side of the first core portion 11 pressed in Step 2.

[0112] <Example 12> In Step 3, heat treatment was performed on a range of 11.7 mm from the leading end to the base end side of the first core portion 11 pressed in Step 2.

[0113] <Example 13> In Step 3, heat treatment was performed on the range of 14.4 mm from the tip end to the base end side of the first core part 11 pressed in Step 2.

[0114] <Example 14> In Step 3, heat treatment was performed on the range of 16.0 mm from the tip end to the base end side of the first core part 11 pressed in Step 2.

[0115] <Example 15> In Step 3, heat treatment was performed on the range of 18.9 mm from the tip end to the base end side of the first core part 11 pressed in Step 2.

[0116] <Example 16> In Step 3, heat treatment was performed on the range of 20.6 mm from the tip end to the base end side of the first core part 11 pressed in Step 2.

[0117] Also, the guide wires of Example 7 and Example 8 were manufactured in the same manner as Example 1 for Steps 1 and 4 to 6, and Steps 2 and 3 were manufactured as follows.

[0118] <Example 7> (Step 2) Press the range of 16 mm from the tip end to the base end side of the first core part 11 to form the flat plate part 11g and the transition part 11f. At this time, the range of 13 mm from the tip end to the base end side of the guide wire 100 was made into the flat plate part 11g and formed into a flat plate shape with a constant thickness of 32 μm. The range of 3 mm from the base end of the flat plate part 11g to the base end side was made into the transition part 11f and formed into a wedge shape whose thickness increases toward the base end side. (Step 3) In Step 3, heat treatment was performed on the range of 13.6 mm from the tip end to the base end side of the first core part 11 pressed in Step 2.

[0119] <Example 8> (Step 2) Pressed a range of 16 mm from the tip to the base end side of the first core part 11 to form a flat plate part 11g and a transition part 11f. At this time, a range of 13 mm from the tip to the base end side of the guide wire 100 was made into the flat plate part 11g and formed into a flat plate shape with a constant thickness of 32 μm. A range of 3 mm from the base end of the flat plate part 11g to the base end side was made into the transition part 11f and formed into a wedge shape with the thickness increasing toward the base end side. (Step 3) Performed heat treatment on a range of 13.7 mm from the foremost tip to the base end side of the first core part 11 pressed in Step 2.

[0120] Comparative Examples 1 to 4 were manufactured as follows. Note that for Steps 1, 2, 4 to 6 of Comparative Examples 1 and 2, they were manufactured in the same manner as in Example 1, and Step 3 was manufactured as follows.

[0121] 〈Comparative Example 1〉 In Step 3, the first core part 11 pressed in Step 2 was not subjected to heat treatment.

[0122] 〈Comparative Example 2〉 In Step 3, heat treatment was performed on a range of 13.7 mm from the foremost tip to the base end side of the first core part 11 pressed in Step 2.

[0123] Also, Comparative Examples 3 and 4 were manufactured as follows. For Comparative Examples 3 and 4, Steps 1 and 4 to 6 were manufactured in the same manner as in Example 1, and Steps 2 and 3 were manufactured as follows.

[0124] 〈Comparative Example 3〉 (Step 2) Pressed a range of 16 mm from the tip to the base end side of the first core part 11 to form a flat plate part 11g and a transition part 11f. At this time, a range of 13 mm from the tip to the base end side of the guide wire 100 was made into the flat plate part 11g and formed into a flat plate shape with a constant thickness of 32 μm. A range of 3 mm from the base end of the flat plate part 11g to the base end side was made into the transition part 11f and formed into a wedge shape with the thickness increasing toward the base end side. (Step 3) Heat treatment was performed on the range of 14.3 mm from the tip to the base end side of the first core part 11 pressed in Process 2.

[0125] <Comparative Example 4> (Process 2) A range of 16 mm from the tip to the base end side of the first core part 11 was pressed to form the flat plate part 11g and the transition part 11f. At this time, a range of 13 mm from the tip to the base end side of the guide wire 100 was made into the flat plate part 11g and formed into a flat plate shape with a constant thickness of 32 μm. A range of 3 mm from the base end of the flat plate part 11g to the base end side was made into the transition part 11f and formed into a wedge shape whose thickness increases toward the base end side. (Process 3) Heat treatment was performed on the range of 13.0 mm from the tip to the base end side of the first core part 11 pressed in Process 2.

[0126] [Evaluation Method] The evaluation of the guide wire 100 for Examples 1 to 16 and Comparative Examples 1 to 4 was carried out as follows.

[0127] <Measurement of Elastic Deformation Work Rate and Martensitic Hardness> -Apparatus- Dynamic Ultra-Micro Rigidity Meter DUH-211S manufactured by Shimadzu Corporation -Measurement Conditions- · Measuring indenter: Triangular indenter (inter-edge angle 115°), accessory of the equipment (Triangular115) · Environmental conditions: Temperature 22 ± 1°C -Measurement Method and Procedure- · Test method: Load-unload test (compliant with "Instrumented Indentation Hardness" ISO14577-1) · Penetration depth: 0.5 μm · Holding time: 0 seconds · Measurement position: Any 10 locations on a cross-section parallel to the plane seen from the thickness direction of the flat plate part 11g -Calculation Method- The elastic deformation work rate and martensitic hardness of the guide wire 100 in each example and each comparative example were taken as the average value of the measured values at any 10 locations in a cross-section parallel to the plane viewed from the thickness direction of the flat portion 11g. The elastic deformation work rate was rounded to one decimal place, and the martensitic hardness was rounded to an integer.

[0128] 〈Shape-forming property test〉 The shape-forming test was carried out as follows. First, the tip 5 mm portion of the guide wire 100 was sandwiched between a silicone rubber plate placed on a substantially horizontal plane and a stainless steel round bar (φ0.7 mm), and the round bar was pressed with a load of 100 g. Next, the guide wire 100 was pulled out vertically from the silicone rubber plate, and the shape of the tip portion of the guide wire 100 was visually observed. For the evaluation, if the tip portion of the guide wire 100 after the test was significantly deformed compared to before the test, it was rated as "〇"; if it was deformed but to a small extent, it was rated as "△"; and if it was not deformed, it was rated as "×".

[0129] 〈Shape retention test〉 The shape retention test was carried out as follows. The guide wire 100 was deformed and shaped with a curvature radius of 3.5 mm from the position 2 mm from the tip to the position 7 mm from the tip. The shaped guide wire 100 was inserted into a U-shaped passage having a curvature radius of 15 mm, rotated a total of 10 times alternately to the left and right, and then pulled out to check the shape of the tip portion of the guide wire 100. For the evaluation, when a perpendicular line was dropped from the tip of the guide wire 100 to the central axis C, if the distance between the foot of the perpendicular line before the test and the foot of the perpendicular line after the test on the central axis C was within 1 mm, it was considered that the shape could be retained and rated as "〇"; if it was greater than 1 mm, it was considered that the shape could not be retained and rated as "×". Note that the smaller the curvature radius of the U-shaped passage, the greater the external force the guide wire 100 receives, and the more difficult it is to retain the shape during shaping.

[0130] 〈Anti-prolapse property test〉 The anti-prolapse test was conducted as follows. First, a branch model 200 made of a silicone resin tube shown in Fig. 5A was prepared. The branch model 200 includes a main stem 210 and a plurality of side branches 220 arranged along the long axis direction of the main stem 210. The inner diameter of the main stem 210 was 3 mm, and the inner diameter of the side branch 220 was 2 mm. In Fig. 5A, the tip-side angles θ (θ1 to θ7) formed by the central axis of the main stem 210 and the central axis of the side branch 220 were θ1 = 90°, θ2 = 100°, θ3 = 110°, θ4 = 120°, θ5 = 130°, θ6 = 140°, and θ7 = 150°.

[0131] Next, the tip of the guide wire 100 was shaped. As shown in Fig. 5B, the shaping was performed to have a shape deformed by approximately 135° in the same direction at each of the first bending point P1 at a position 1 mm from the tip of the guide wire 100 and the second bending point P2 at a position 5 mm. Next, the guide wire 100 was inserted into each side branch 220 from the insertion port 200a of the branch model 200 filled with water. Among the side branches 220 into which the guide wire 100 could be inserted, the maximum angle θ was recorded. If the maximum angle θ at which the guide wire 100 could be inserted was small, it could be said that prolapse was likely to occur. Therefore, for the evaluation, among the side branches 220 into which the guide wire 100 could be inserted, when the maximum angle θ was θ ≤ 100°, it was marked as "×", when the angle θ was 100° < θ ≤ 110°, it was marked as "△", and when the angle θ was 110° < θ ≤ 120°, it was marked as "〇".

[0132] 〈Anti-kinking test〉 The kink resistance test was conducted as follows. As shown in Fig. 6, a stenosis model 300 with one end of a tube having an inner diameter of 2.5 mm closed was prepared. The tip of the guide wire 100 was shaped into the shape shown in Fig. 5B. The tip of the guide wire 100 was inserted from the open end of the stenosis model 300 filled with water and abutted against the closed end as shown by the two-dot chain line in Fig. 6 for the guide wire 100. Next, the guide wire 100 was pushed 10 mm in the tip direction while applying torque, and the tip of the guide wire 100 was bent into a U shape as shown by the solid line in Fig. 6 for the guide wire 100. Thereafter, it was pulled 10 mm in the major axis direction to return to the state where it was not bent into a U shape. This operation was performed a total of 3 times. The torque applied to the guide wire 100 was applied by the tester rotating it once while holding the proximal end portion of the guide wire 100. The guide wire 100 was removed from the stenosis model 300, and the bending height L of the guide wire 100 was confirmed with a digital microscope. The "bending height L" refers to the length from the tip of the guide wire 100 in the straight line state before shaping to the tip of the guide wire 100 after the kink resistance test on the plane passing through the central axis C of the guide wire 100 when the guide wire 100 was in the natural state, as shown in Fig. 7. The evaluation was "〇" when the bending height L of the guide wire 100 after the kink resistance test was less than 4 mm, and "×" when the bending height L was 4 mm or more.

[0133] [Evaluation Results] Table 3 shows the evaluation results of Examples 1 to 16, and Table 4 shows the evaluation results of Comparative Examples 1 to 4. Note that "ND" in the table means not measured.

[0134]

Table 3

[0135]

Table 4

[0136] 〈Shape Forming Test and Shape Retention Test〉 As shown in Table 3, for the guide wires 100 of Examples 1 to 16, the results of both the shape-forming property test and the shape-retention property test were either "〇" or "△". The guide wires 100 of Examples 1 to 16 had an elastic deformation work rate of the Ni-Ti alloy in the flat plate portion 11g of 46.0% or more and 59.5% or less, and a martensite hardness of 1300 N / mm 2 or more and 3000 N / mm 2 or less (Condition 1).

[0137] On the other hand, as shown in Table 4, for the guide wires 100 of Comparative Examples 1 to 4, the result of either the shape-forming property test or the shape-retention property test was "×". For the guide wires 100 of Comparative Example 1 and Comparative Example 4, the result of the shape-retention property test was "〇", but the result of the shape-forming property test was "×". It is presumed that the guide wire 100 of Comparative Example 1 could not be shaped because its martensite hardness was greater than the upper limit value of Condition 1 and it was harder compared to Examples 1 to 16. It is presumed that the guide wire 100 of Comparative Example 4 could not be shaped because its elastic deformation work rate was greater than the upper limit value of Condition 1 and its superelasticity was higher compared to Examples 1 to 16. Also, as shown in Table 4, for the guide wires 100 of Comparative Example 2 and Comparative Example 3, the result of the shape-forming property test was "〇", but the result of the shape-retention property test was "×". It is presumed that the guide wire 100 of Comparative Example 2 easily underwent plastic deformation because its martensite hardness was less than the lower limit value of Condition 1 and it was softer compared to Examples 1 to 16. It is presumed that the guide wire 100 of Comparative Example 3 underwent plastic deformation because its elastic deformation work rate was less than the lower limit value of Condition 1 and its superelasticity was lower compared to Examples 1 to 16.

[0138] As described above, the guide wire 100 formed of a Ni-Ti alloy in which the flat plate portion 11g satisfied the above Condition 1 had both shape-forming property and shape-retention property.

[0139] Also, as shown in Table 3, for the guide wires 100 of Examples 1 to 3, the result of the shaping test was "Δ", and for the guide wires 100 of Examples 4 to 16, the result of the shaping test was "〇". For the guide wires 100 of Examples 4 to 16, the elastic deformation work rate of the Ni-Ti alloy in the flat plate portion 11g was 46.0% or more and 59.5% or less, and the martensite hardness was 1300 N / mm 2 or more and 2120 N / mm 2 or less (Condition 2). Since the martensite hardness of the guide wires 100 of Examples 1 to 3 was greater than the upper limit value of Condition 2, it is presumed that they were harder and more difficult to shape compared to the guide wires 100 of Examples 4 to 16.

[0140] As described above, the guide wire 100 formed of the Ni-Ti alloy in which the flat plate portion 11g satisfied the above Condition 2 was further excellent in both shape formability and shape retention.

[0141] 〈Anti-prolapse test〉 As shown in Table 3, for the guide wires 100 of Examples 1, 3 to 4, 6 to 8, and 11 to 16, the result of the anti-prolapse test was either "〇" or "Δ". On the other hand, for the guide wires 100 of Examples 9 and 10, the result of the anti-prolapse test was "×". For all of the guide wires 100 of Examples 1, 3 to 4, 6 to 8, and 11 to 16, the ratio of the length along the major axis from the tip of the transition portion 11f to the base end of the heat treatment region H to the length along the major axis of the transition portion 11f in the length along the major axis direction of the transition portion 11f (heat treatment ratio) was 10% or more and 100% or less (Condition 3). In contrast, for the guide wires 100 of Examples 9 and 10, the heat treatment ratio of both was less than the lower limit value of Condition 3, and heat treatment was performed only on a part of the flat plate portion 11g or a very small part on the tip side of the flat plate portion 11g and the transition portion 11f. Therefore, as shown in FIG. 4B, for the guide wires 100 of Examples 9 and 10, a sudden change in rigidity occurred near the boundary between the flat plate portion 11g and the transition portion 11f, and it is presumed that the anti-prolapse property decreased.

[0142] Also, as shown in Table 3, for the guide wires 100 of Example 4 and Examples 6 to 8, the results of the anti-prolapse property test were "〇". On the other hand, for example, for the guide wires 100 of Example 12 and Example 13, the results of the anti-prolapse property test were "△". For all of the guide wires 100 of Example 4 and Examples 6 to 8, the ratio of the length along the major axis from the tip of the transition portion 11f to the base end of the heat treatment region H to the length along the major axis of the transition portion 11f occupies 55% or more and 65% or less (Condition 4). In contrast, for the guide wire 100 of Example 12, the heat treatment ratio is smaller than the lower limit value of Condition 4, and the base end of the heat treatment region H is arranged at the tip of the transition portion 11f with low rigidity. Therefore, it is presumed that for the guide wire 100 of Example 12, a sudden change in rigidity occurs at the base end of the heat treatment region H, resulting in a decrease in anti-prolapse property. Also, for the guide wire 100 of Example 13, the heat treatment ratio is larger than the upper limit value of Condition 4, and the length of the portion where the rigidity is decreased due to the heat treatment in the transition portion 11f is long. Therefore, it is presumed that for the guide wire 100 of Example 13, the pushing force is difficult to be transmitted to the tip of the guide wire 100, resulting in a decrease in anti-prolapse property.

[0143] As described above, the guide wire 100 in which the ratio of the length along the major axis from the tip of the transition portion 11f to the base end of the heat treatment region H to the length along the major axis of the transition portion 11f satisfies the above Condition 3, and more preferably satisfies the above Condition 4, has excellent anti-prolapse property.

[0144] 〈Kink Resistance Test〉 As shown in Table 3, for the guide wires 100 of Example 1, Examples 3 to 4, and Examples 6 to 14, the result of the kink resistance test was "〇". On the other hand, for the guide wires 100 of Example 15 and Example 16, the result of the kink resistance test was "×". For the guide wires 100 of Example 1, Examples 3 to 4, and Examples 6 to 14, in all cases, the ratio of the length along the major axis from the tip of the transition portion 11f to the base end of the heat treatment region H to the length along the major axis of the transition portion 11f occupying the length along the major axis direction is 10% or more and 100% or less (Condition 3). In contrast, in Example 15 and Example 16, the heat treatment ratio is greater than the upper limit value of Condition 3, and the heat treatment is performed up to the portion that has not been cold-worked. Since the core member 10 is made of a Ni-Ti alloy, when the portion that has not been cold-worked is heat-treated, the superelasticity decreases and it becomes easy to plastically deform. Therefore, it is presumed that the kink resistance of the guide wires 100 of Example 15 and Example 16 has decreased.

[0145] As described above, the guide wire 100 in which the heat treatment ratio in the transition portion 11f satisfies the above Condition 3 was excellent in kink resistance.

[0146] This application is based on Japanese Patent Application No. 2020-183259 filed on October 30, 2020, and the entire disclosure thereof is incorporated herein by reference in its entirety.

Explanation of Reference Numerals

[0147] 10 Core member, 11 First core part (11a First joint part, 11b First constant outer diameter part, 11c First tapered part, 11d Second constant outer diameter part, 11e Second tapered part, 11f Transition part, 11g Flat plate part), 12 Second core part (12a Base part, 12b Second joint part), 13 Joint surface, 20 Tube cavity, 21 First coil, 22 Second coil, 30 Fixed part, 31 Tip fixed part, 32 Intermediate fixed part (32a Cylindrical member), 33 Base end fixing part, 40 Coating layer, 41 First coating layer, 42 Second coating layer, 43 Third coating layer, 100 Guide wire, C Central axis, H Heat treatment area.

Claims

1. comprising a long core member having a flat plate portion at the tip; The flat plate portion is made of a Ni-Ti alloy having an elastic deformation work rate of 46.0% or more and 59.5% or less, and a martensite hardness of 1300 N / mm ２ or more and 3000 N / mm ２ or less. The guide wire is made of a Ni-Ti alloy.

2. The martensite hardness is 1300 N / mm ２ or more and 2120 N / mm ２ or less. The guide wire according to claim 1

3. the core member has, in order from the tip side, the flat plate portion and a transition portion extending from the base end of the flat plate portion along the major axis direction toward the base end side; the core member has a heat treatment region extending from the tip of the flat plate portion to at least a part of the transition portion, the guide wire according to claim 1 or 2.

4. The ratio of the length along the major axis direction from the tip of the transition portion to the base end of the heat treatment region to the length along the major axis direction of the transition portion is 10% or more and 100% or less, the guide wire according to claim 3.

5. The ratio of the length along the major axis direction from the tip of the transition portion to the base end of the heat treatment region to the length along the major axis direction of the transition portion is 55% or more and 65% or less, the guide wire according to claim 4.

6. A method for manufacturing a guide wire provided with a core member, comprising: a step of performing cold working on the tip portion of the core member so as to have a flat plate portion and a transition portion extending from the base end of the flat plate portion along the major axis direction toward the base end side; For at least a part of the flat plate portion and the transition portion, the elastic deformation work rate is 46.0% or more and 59.5% or less, and the martensite hardness is 1300 N / mm ２ or more and 3000 N / mm ２ or less, and a method for manufacturing a guide wire including a step of performing heat treatment so as to satisfy the above conditions.

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