Guide wire

Abstract

To provide a guide wire whose end part is easily bendable in a specific surface direction in shaping.SOLUTION: A guide wire includes a core shaft. When a diameter whose length in a cross section orthogonal to an axial direction of the core shaft is maximum is a maximum diameter, a diameter in the direction orthogonal to the direction of the maximum diameter in the cross section is an orthogonal diameter, and value after dividing the difference between the maximum diameter and the orthogonal diameter by the maximum diameter is a flat rate, the core shaft has a first specific part which is located on an end side of the core shaft and whose flat rate is between 7% and 35%. The first specific part in the axial direction of the core shaft is 5 mm or longer.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The technology disclosed herein relates to medical guidewires. [Background technology]

[0002] Methods using catheters are widely used as methods for treating or inspecting stenosis or occlusion (hereinafter referred to as "lesion") in blood vessels, etc. Generally, a guidewire is used to guide the catheter to the lesion in the blood vessel, etc. The guidewire includes a core shaft formed of, for example, a metallic material (see, for example, Patent Document 1).

[0003] In many conventional guidewires, the cross section of the tip portion of the guidewire (the cross section perpendicular to the axial direction of the core shaft) is circular.

[0004] In a method using a guidewire, in order to improve the blood vessel selectivity of the guidewire, a procedure called "shaping" is sometimes performed in which an operator such as a doctor bends the tip of the guidewire to a predetermined angle before inserting the guidewire into a blood vessel, etc. Conventionally, the tip of a guidewire, which has a circular cross section, is bent by shaping. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2012-91070 A Summary of the Invention [Problem to be solved by the invention]

[0006] In shaping, it may be required that the bending direction of the tip portion of the guidewire after shaping be limited to a predetermined direction (strictly speaking, a direction along a certain plane along the axial direction of the guidewire; hereinafter, referred to as a "specific plane direction") (sometimes referred to as "two-dimensional shaping"). For example, when performing shaping to bend a first portion including the tip of the guidewire and a second portion located closer to the base end of the guidewire than the first portion, it is required that both the bending direction of the first portion and the bending direction of the second portion be limited to the same specific plane direction.

[0007] In a configuration in which the cross section of the tip of the guidewire (a cross section perpendicular to the axial direction of the core shaft) is circular, the ease of deformation of the tip of the guidewire does not differ depending on the deformation direction. Therefore, in this configuration, the tip of the core shaft (and therefore the tip of the guidewire) may deform in a direction other than the specific planar direction (sometimes called "three-dimensional shaping"). Therefore, in this configuration, it is not easy to bend the tip of the guidewire in the specific planar direction (or in a direction close to the specific planar direction) during shaping.

[0008] This specification discloses a technique that can solve the above-mentioned problems. [Means for solving the problem]

[0009] The technology disclosed in this specification can be realized, for example, in the following forms.

[0010] (1) A guidewire disclosed in the present specification is a guidewire including a core shaft, wherein a maximum diameter is a diameter at which the length is maximum in a cross section perpendicular to the axial direction of the core shaft, a diameter in a direction perpendicular to the direction of the maximum diameter in the cross section is a orthogonal diameter, and a flattening ratio is a value obtained by dividing the difference between the maximum diameter and the orthogonal diameter by the maximum diameter. The core shaft has a first specific portion located on the tip side of the core shaft and having a flattening ratio of 7% or more and 35% or less, and the first specific portion in the axial direction is 5 mm or more.

[0011] As described above, in this guidewire, the flattening ratio of the first specific portion is 7% or more. The length of the first specific portion in the axial direction is 5 mm or more. Therefore, according to this guidewire, the first specific portion can be easily bent in a specific planar direction (specifically, a plane along the axial direction and the orthogonal radial direction) or in a direction close to the specific planar direction during shaping.

[0012] In addition, in the present guidewire, the flattening ratio of the first specific portion is 35% or less as described above, so that the present guidewire can ensure rotation performance of the guidewire while being configured to easily bend the first specific portion in a specific planar direction during shaping as described above.

[0013] (2) In the above guidewire, the first specific portion may be formed of a material containing stainless steel. In this guidewire, the first specific portion is formed of a material containing stainless steel that is easily plastically deformed, so that deformation due to shaping tends to remain without returning to its original shape, making shaping easy.

[0014] (3) In the above guidewire, the core shaft may have a second specific portion located on the distal side of the core shaft relative to the first specific portion and having a flattening ratio of 40% or more. This guidewire is particularly suitable for use in a state in which the second specific portion is bent relatively slightly and the first specific portion located on the distal side of the second specific portion is bent relatively greatly.

[0015] (4) In the above guidewire, the direction of the maximum diameter of the first specific portion and the direction of the maximum diameter of the second specific portion may be parallel to each other. This guidewire is particularly suitable for use in a state in which the first specific portion is bent relatively slightly and the second specific portion located distal to the first specific portion is bent relatively greatly.

[0016] (5) In the above guidewire, the second specific portion may be formed of a material containing stainless steel. In this guidewire, the first specific portion is formed of a material containing stainless steel that is easily plastically deformed, so that deformation due to shaping tends to remain without returning to its original shape, making shaping easy.

[0017] (6) In the above guidewire, the core shaft may be configured to have a superelastic portion located closer to the proximal end of the guidewire than the first specific portion and formed of a material containing a superelastic alloy. According to this guidewire, the first specific portion can be easily bent in a specific plane direction during shaping as described above, while ensuring the operability and blood vessel selectivity of the guidewire.

[0018] The techniques disclosed in this specification can be realized in various forms, for example, in the form of a guidewire or a manufacturing method thereof. [Brief description of the drawings]

[0019] [Figure 1] FIG. 1 is a side view showing a schematic overall configuration of a guidewire according to a first embodiment; [Diagram 2] FIG. 1 is an enlarged side view of a portion of a core shaft according to a first embodiment; [Diagram 3] FIG. 3 is a cross-sectional view showing a cross-sectional configuration of a core shaft taken along the line III-III in FIG. 2 . [Figure 4] FIG. 4 is a cross-sectional view showing a cross-sectional configuration of a core shaft taken along the line IV-IV in FIG. [Diagram 5] FIG. 3 is a cross-sectional view showing a cross-sectional configuration of the core shaft at the position VV in FIG. [Figure 6] FIG. 13 is an explanatory diagram showing the evaluation results regarding the directionality of shaping in this embodiment. [Figure 7] FIG. 13 is an explanatory diagram showing the evaluation results regarding the directionality of shaping in this embodiment. [Figure 8] An explanatory diagram for explaining a method for measuring the directionality of shaping [Figure 9] FIG. 13 is an explanatory diagram showing the evaluation results regarding the rotation performance in this embodiment. [Figure 10] FIG. 13 is an explanatory diagram showing the evaluation results regarding the rotation performance in this embodiment. [Figure 11] FIG. 13 is an explanatory diagram showing an example of a measurement result regarding the directionality of shaping in this embodiment. [Figure 12] FIG. 1 is an explanatory diagram for explaining a method for measuring rotation performance. [Figure 13] FIG. 13 is a side view showing a schematic overall configuration of a guidewire according to a second embodiment. [Figure 14] FIG. 11 is an enlarged side view of a portion of a core shaft according to a second embodiment. [Figure 15] FIG. 15 is a cross-sectional view showing a cross-sectional configuration of the core shaft taken along the line XV-XV in FIG. [Figure 16] FIG. 13 is a side view showing a schematic overall configuration of a guidewire according to a third embodiment. [Figure 17] FIG. 17 is a cross-sectional view showing a cross-sectional configuration of the core shaft taken along the line XVII-XVII of FIG. [Figure 18] FIG. 18 is a cross-sectional view showing a cross-sectional configuration of the core shaft taken along the line XVIII-XVIII of FIG. [Figure 19] FIG. 13 is a side view showing a schematic overall configuration of a guidewire according to a fourth embodiment. [Figure 20] FIG. 20 is a cross-sectional view showing a cross-sectional configuration of the core shaft taken along the line XX-XX in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] A. First embodiment: A-1. Configuration of guidewire 100: FIG. 1 is a side view showing a schematic overall configuration of the guidewire 100 in the first embodiment. In FIG. 1, mutually orthogonal XYZ axes for specifying a direction are shown, and the overall configuration of the guidewire 100 as viewed in the positive X-axis direction is shown. In FIG. 1, the positive Z-axis direction side is the tip side (distal side) inserted into the body, and the negative Z-axis direction side is the base side (proximal side) operated by an operator such as a doctor. These points are the same for FIG. 2 and subsequent figures. In FIG. 1, a cross-sectional (specifically, YZ cross-sectional) configuration is shown for the coil body 20 and the tip-side joint portion 30 described later. In FIG. 1, the guidewire 100 is shown in a state in which the guidewire 100 is generally linearly shaped substantially parallel to the Z-axis direction, but the guidewire 100 has flexibility to the extent that it can be bent. In the following, the guidewire 100 and each component of the guidewire 100 will be referred to as a "tip portion" that includes the tip and extends from the tip to the middle of the base end. Similarly, for guidewire 100 and each of its constituent members, the portion including the base end and extending from the base end to partway toward the tip side is referred to as the "base portion."

[0021] The guidewire 100 is a medical device that is inserted into a blood vessel or the like in order to guide a catheter (not shown) to a lesion (a narrowed or blocked area) in the blood vessel or the like. As shown in FIG. 1, the guidewire 100 includes a core shaft 10, a coil body 20, a distal joint 30, and a proximal joint 40.

[0022] The core shaft 10 is a rod-shaped member having a small diameter at the tip end and a large diameter at the base end. The core shaft 10 includes a first core shaft portion 11 including the tip end of the core shaft 10, and a second core shaft portion 12 located on the base end side of the core shaft 10A with respect to the first core shaft portion 11. The first core shaft portion 11 will be described in detail later.

[0023] The second core shaft portion 12 has a small diameter portion 120, a large diameter portion 121, and a tapered portion 122. Note that a part of the large diameter portion 121 of the second core shaft portion 12 is omitted in Fig. 1. The second core shaft portion 12 is an example of a superelastic portion in the claims.

[0024] The thin-diameter section 120 of the second core shaft portion 12 is a portion that includes the tip of the second core shaft portion 12. The thin-diameter section 120 is rod-shaped with a circular cross section. The cross section is a cross section (in this embodiment, an XY cross section) perpendicular to the axial direction of the core shaft 10 (in this embodiment, the Z-axis direction) (the same applies to the second and subsequent embodiments). In this embodiment, the axial direction of the core shaft 10 coincides with the axial direction of the guidewire 100.

[0025] The large diameter portion 121 of the second core shaft portion 12 is located on the base end side of the core shaft 10A with respect to the small diameter portion 120, and has a rod-like shape with a circular cross section having a larger outer diameter than the small diameter portion 120.

[0026] Tapered portion 122 of second core shaft portion 12 is located between thin diameter portion 120 and thick diameter portion 121. The outer diameter of tapered portion 122 gradually increases from the boundary position with thin diameter portion 120 toward the boundary position with thick diameter portion 121.

[0027] The cross-sectional shape of each part of the second core shaft portion 12 is not particularly limited, and may be, for example, a polygon such as a triangle or a rectangle.

[0028] Examples of materials for forming the second core shaft portion 12 include metal materials, more specifically, stainless steels (SUS302, SUS304, SUS316, etc.), superelastic alloys such as Ni-Ti alloys, piano wire, nickel-chromium alloys, cobalt alloys, tungsten, etc., but in this embodiment, the second core shaft portion 12 is formed of a material containing a superelastic alloy such as Ni-Ti alloy. In this embodiment, the second core shaft portion 12 is configured to be formed of a material containing a superelastic alloy, so that even when the guidewire 100 advances through a curved blood vessel or the like, the second core shaft portion 12 can exhibit the ability to return to its original shape after being deformed (sometimes referred to as "restorability"). This ensures the operability and blood vessel selectivity of the guidewire 100.

[0029] The coil body 20 is a coil-shaped member formed into a hollow cylinder by helically winding a single wire. The coil body 20 is disposed so as to surround the outer periphery of the tip end of the core shaft 10 (specifically, the first core shaft portion 11, and a part of the small diameter portion 120, the tapered portion 122, and the large diameter portion 121 of the second core shaft portion 12).

[0030] The coil body 20 is made of, for example, a metal material, more specifically, a radiolucent alloy such as stainless steel (SUS302, SUS304, SUS316, etc.), a superelastic alloy such as a Ni-Ti alloy, a piano wire, a nickel-chromium alloy, or a cobalt alloy, or a radiopaque alloy such as gold, platinum, tungsten, or an alloy containing these elements (for example, a platinum-nickel alloy). When at least a portion of the coil body 20 is made of a radiopaque material, the operator can grasp the position of the coil body 20 under a radioscopic image.

[0031] The tip side joint 30 joins the tip of the core shaft 10 and the tip of the coil body 20. The tip of the core shaft 10 and the tip of the coil body 20 are fixed to each other so as to be embedded inside the tip side joint 30. The outer peripheral surface on the tip side of the tip side joint 30 is a smooth surface (for example, a substantially hemispherical surface). The tip side joint 30 is made of, for example, a metal solder such as silver solder, gold solder, zinc, Sn-Ag alloy, Au-Sn alloy, or an adhesive such as an epoxy adhesive. By arranging the tip side joint 30 on the tip side of the core shaft 10, the core shaft 10 is prevented from contacting a blood vessel wall or the like, and thus the core shaft 10 is prevented from being damaged or the like.

[0032] The base-end joint 40 is a member that joins the base-end side of the core shaft 10 and the base-end side of the coil body 20. The base-end joint 40 is made of the same material as the above-mentioned tip-end joint 30. Note that the base-end joint 40 is not limited to being located on the base-end side of the coil body 20, and may be located at any position on the coil body 20.

[0033] A-2. Detailed configuration of the first core shaft portion 11: Fig. 2 is an enlarged side view of a portion of the core shaft 10 in the first embodiment. Fig. 2 shows the configuration of a portion of the core shaft 10 (part X1 in Fig. 1) as viewed in the positive direction of the X-axis. Fig. 3 shows the cross-sectional configuration of the core shaft 10 at the position III-III in Fig. 2, Fig. 4 shows the cross-sectional configuration of the core shaft 10 at the position IV-IV in Fig. 2, and Fig. 5 shows the cross-sectional configuration of the core shaft 10 at the position VV in Fig. 2. Figs. 3 to 5 show the cross-sectional configuration of the core shaft 10 as viewed in the negative direction of the Z-axis.

[0034] The first core shaft portion 11 is a rod-shaped member. In this embodiment, the first core shaft portion 11 is formed of a material including stainless steel (SUS302, SUS304, SUS316, etc.). The first core shaft portion 11 is sometimes called a "ribbon" or a "shaping ribbon." The first core shaft portion 11 is connected to the tip of the second core shaft portion 12 (the thin diameter portion 120) (for example, joined by a metal solder such as silver solder, gold solder, zinc, Sn-Ag alloy, Au-Sn alloy, or an adhesive such as an epoxy adhesive).

[0035] 2, the first core shaft portion 11 has a high flat portion 110, a low flat portion 112, and a tapered portion 111. The high flat portion 110 of the first core shaft portion 11 is an example of a second specific portion in the claims, and the low flat portion 112 of the first core shaft portion 11 is an example of a first specific portion in the claims.

[0036] In the following, the diameter having the maximum length in a cross section (a cross section perpendicular to the axial direction of the core shaft 10 (in this embodiment, the Z-axis direction) (in this embodiment, the XY cross section)) is referred to as the "maximum diameter", the diameter having the maximum length in a direction perpendicular to the direction of the maximum diameter in the cross section is referred to as the "orthogonal diameter", and the value (%) obtained by dividing the difference between the maximum diameter and the orthogonal diameter by the maximum diameter is referred to as the "flatness ratio".

[0037] The high flat portion 110 of the first core shaft portion 11 is a portion that includes the tip end of the first core shaft portion 11 .

[0038] 3, the cross section of the highly flat portion 110 has a flat shape (approximately rectangular or elliptical) with the major axis extending in the X-axis direction and the minor axis extending in the Y-axis direction. In the cross section of the highly flat portion 110, the major axis corresponds to the maximum diameter D11, and the minor axis corresponds to the orthogonal diameter D12.

[0039] The flatness ratio of the cross section of the highly flattened portion 110 of the first core shaft portion 11 is 40% or more. As a specific example, when the wire diameter (the diameter of the rod-shaped member before flattening such as press working described later; the same applies below) is 40 μm, the maximum diameter D11 of the highly flattened portion 110 is 57 μm, the orthogonal diameter D12 is 24 μm, and the flatness ratio is 57.9%. The flatness ratio of the cross section of the highly flattened portion 110 of the first core shaft portion 11 may be another value that is 40% or more (the same applies to the third embodiment described below).

[0040] 2, the low flat portion 112 of the first core shaft portion 11 is a portion including the base end of the first core shaft portion 11. The low flat portion 112 has a connection portion with the tip end of the second core shaft portion 12 (the thin diameter portion 120) on the base end side of the low flat portion 112.

[0041] 4, the cross section of the low flat portion 112 has a flat shape (approximately rectangular or elliptical) with the diameter in the X-axis direction as the major axis and the diameter in the Y-axis direction as the minor axis. In the cross section of the low flat portion 112, the major axis corresponds to the maximum diameter D21, and the minor axis corresponds to the orthogonal diameter D22.

[0042] The flatness ratio of the low flat portion 112 of the first core shaft portion 11 is 7% or more and 35% or less. As a specific example, when the wire diameter is 40 μm and the flatness ratio is 30.0%, the maximum diameter D21 is 46 μm and the orthogonal diameter D22 is 32 μm in the low flat portion 112. When the flatness ratio is 7.3%, the maximum diameter D21 is 41 μm and the orthogonal diameter D22 is 38 μm. When the wire diameter is 75 μm and the flatness ratio is 31.0%, the maximum diameter D21 is 87 μm and the orthogonal diameter D22 is 60 μm, and when the flatness ratio is 7.8%, the maximum diameter D21 is 77 μm and the orthogonal diameter D22 is 71 μm.

[0043] 2, the tapered portion 111 of the first core shaft portion 11 is located between the high flat portion 110 and the low flat portion 112. The flatness ratio of the tapered portion 111 changes stepwise or gradually from the boundary position with the high flat portion 110 to the boundary position with the low flat portion 112.

[0044] The first core shaft portion 11 having the above-mentioned flattened (approximately rectangular or elliptical) cross section can be manufactured by performing flattening processing such as press processing on a rod-shaped member having a circular cross section, which is formed, for example, from a material including stainless steel.

[0045] A-3. Advantages of the first embodiment: As described above, the guidewire 100 of the first embodiment includes the core shaft 10. The core shaft 10 has a low flattened portion 112 (of the first core shaft portion 11) located on the distal end side of the core shaft 10 and having a flattening ratio of 7% or more and 35% or less. The length of the low flattened portion 112 of the first core shaft portion 11 in the axial direction of the core shaft 10 (the Z-axis direction in this embodiment) is 5 mm or more.

[0046] If the distal end of guidewire 100 has a circular cross section, the ease of deformation of the distal end of guidewire 100 does not differ depending on the deformation direction. Therefore, in this configuration, the distal end of core shaft 10 (and thus the distal end of guidewire 100) may deform in a direction different from the specific planar direction (sometimes called "three-dimensional shaping"). Therefore, in this configuration, it is not easy to bend the distal end of guidewire 100 in the specific planar direction (or a direction close to the specific planar direction) during shaping.

[0047] In contrast, in the guidewire 100 of the first embodiment, as described above, the flatness ratio of the low flat portion 112 of the first core shaft portion 11 is 7% or more. The length of the low flat portion 112 of the first core shaft portion 11 in the axial direction of the core shaft 10 is 5 mm or more. Therefore, in the guidewire 100 of the first embodiment, the bending direction of the low flat portion 112 tends to be limited to a specific surface direction (specifically, a direction along a surface along the axial direction of the core shaft 10 and the direction of the orthogonal diameter D22 (in this embodiment, the YZ surface)) in shaping, compared to a configuration in which the cross section of the low flat portion 112 of the first core shaft portion 11 is circular (in other words, the flatness ratio is 0%). Therefore, according to the guidewire 100 of the first embodiment, the low flat portion 112 of the first core shaft portion 11 can be easily bent in a specific surface direction (or a direction close to the specific surface direction) in shaping.

[0048] Furthermore, in a configuration in which the flattening ratio of the low flattening portion 112 of the first core shaft portion 11 is 40% or more, due to the high flattening ratio (in other words, the difference between the maximum diameter D21 and the orthogonal diameter D22 is large), when the guidewire 100 inserted into a blood vessel or the like is rotated, the tip portion of the guidewire 100 (the periphery of the low flattening portion 112 of the first core shaft portion 11) may exhibit a behavior known as "whip" in which the tip portion bounces back and forth like a whip while contacting the blood vessel wall or the like, which may reduce the rotation performance (operability) of the guidewire 100.

[0049] In contrast, in the guidewire 100 of the first embodiment, the flattening ratio of the low flat portion 112 of the first core shaft portion 11 is 35% or less, as described above. Therefore, in the guidewire 100 of the first embodiment, the occurrence of whip is suppressed when the guidewire 100 inserted into a blood vessel or the like is rotated, and thus the deterioration of the rotation performance of the guidewire 100 caused by the occurrence of whip is suppressed. Therefore, according to the guidewire 100 of the first embodiment, the rotation performance of the guidewire 100 can be ensured while the guidewire 100 has a configuration in which the low flat portion 112 of the first core shaft portion 11 can be easily bent in a specific planar direction during shaping as described above.

[0050] In a configuration in which the length of the low flat portion 112 of the first core shaft portion 11 in the axial direction of the core shaft 10 is less than 5 mm, it is difficult to shape the tip portion, but in this embodiment, the length of the low flat portion 112 of the first core shaft portion 11 in the axial direction of the core shaft 10 is 5 mm or more, which makes it easier to shape the tip portion. If the length of the low flat portion 112 of the first core shaft portion 11 in the axial direction of the core shaft 10 is excessively long, whip may easily occur, so the length of the low flat portion 112 of the first core shaft portion 11 in the axial direction of the core shaft 10 is preferably, for example, 15 mm or less.

[0051] In the guidewire 100 of the first embodiment, the wire diameter of the low flattened portion 112 of the first core shaft portion 11 is 40 μm or more. If the wire diameter is less than 40 μm, the shaping directionality is less likely to be limited to a specific planar direction regardless of the flattening ratio. Therefore, in this embodiment in which the wire diameter of the low flattened portion 112 of the first core shaft portion 11 is 40 μm or more, the shaping directionality is more likely to be limited to a specific planar direction than in a configuration in which the wire diameter is less than 40 μm. Therefore, according to this embodiment, the rotation performance of the guidewire 100 can be more reliably ensured.

[0052] Furthermore, in the guidewire 100 of the first embodiment, the low flat portion 112 of the first core shaft portion 11 is formed of a material containing stainless steel. Therefore, in the guidewire 100 of the first embodiment, the low flat portion 112 of the first core shaft portion 11 is formed of a material containing stainless steel that is easily plastically deformed, and therefore deformation due to shaping tends to remain without returning to its original shape, making shaping easy to perform.

[0053] In the guidewire 100 of the first embodiment, the core shaft 10 has a high flat portion 110 of the first core shaft portion 11 that is located on the distal side of the core shaft 10 relative to the low flat portion 112 of the first core shaft portion 11 and has a flatness ratio of 40% or more. Therefore, in the guidewire 100 of the first embodiment, the bending angle due to shaping of the high flat portion 110 located on the distal side of the guidewire 100 relative to the low flat portion 112 of the first core shaft portion 11 is likely to be larger than the bending angle due to shaping of the low flat portion 112 of the first core shaft portion 11. Therefore, the guidewire 100 of the first embodiment is particularly suitable when the guidewire 100 is used in a state in which the low flat portion 112 of the first core shaft portion 11 is bent relatively small and the high flat portion 110 located on the distal side relative to the high flat portion 110 is bent relatively large.

[0054] In the guidewire 100 of the first embodiment, the direction of the maximum diameter D21 of the low flat portion 112 of the first core shaft portion 11 and the direction of the maximum diameter D11 of the high flat portion 110 of the first core shaft portion 11 are parallel to each other. Therefore, the bending direction due to shaping in the low flat portion 112 and the high flat portion 110 of the first core shaft portion 11 tends to be along the direction of the perpendicular diameters D12, D22 rather than the direction of the maximum diameters D11, D21, and is therefore approximately the same planar direction. Therefore, the generation of a three-dimensional shape between the low flat portion 112 and the high flat portion 110 of the first core shaft portion 11 is suppressed, and the directionality of the deformation of the guidewire 100 due to shaping can be limited to a specific planar direction (or a direction close to the specific planar direction).

[0055] Furthermore, in the guidewire 100 of the first embodiment, the highly flattened portion 110 of the first core shaft portion 11 is made of a material containing stainless steel. Therefore, in the guidewire 100 of the first embodiment, the highly flattened portion 110 of the first core shaft portion 11 is made of a material containing stainless steel that is easily plastically deformed, and therefore deformation due to shaping tends to remain without returning to its original shape, making shaping easy to perform.

[0056] In the guidewire 100 of the first embodiment, the core shaft 10 has a second core shaft portion 12 that is located closer to the base end of the guidewire 100 than the low flat portion 112 of the first core shaft portion 11 and is formed of a material containing a superelastic alloy. In the guidewire 100 of the first embodiment, the second core shaft portion 12 that is located closer to the base end of the guidewire 100 than the low flat portion 112 of the first core shaft portion 11 is formed of a material containing a superelastic alloy, so that the second core shaft portion 12 can exhibit restoring properties, thereby ensuring the operability and blood vessel selectivity of the guidewire 100. Therefore, according to the guidewire 100 of the first embodiment, the low flat portion 112 of the first core shaft portion 11 can be easily bent in a specific plane direction during shaping as described above, while still ensuring the operability and blood vessel selectivity of the guidewire 100.

[0057] A-4. Performance evaluation of the first embodiment: A-4-1. Evaluation of shaping direction: A guidewire sample was prepared and used to evaluate the shaping directionality of the guidewire. Figures 6 and 7 are explanatory diagrams showing the evaluation results of the shaping directionality in this embodiment.

[0058] A-4-1-1. For each sample: As shown in Fig. 6 and Fig. 7, in this performance evaluation, 30 guidewire samples (samples 1, 2, ..., 30) were evaluated for shaping directionality. The 30 samples have substantially the same configuration as the above-mentioned guidewire 100 as a whole. Specifically, the 30 samples are guidewires including a core shaft, a coil body, and the like. The core shaft includes a first core shaft portion including a tip end thereof and formed of a material including stainless steel, and a second core shaft portion located on the base end side of the core shaft relative to the first core shaft portion and formed of a material including a superelastic alloy such as a Ni-Ti alloy.

[0059] The 30 samples differ from one another in at least one of the wire diameter (the diameter at the maximum length in the cross section (XY cross section)) and the flattening ratio. Specifically, Samples 1 to 6 have a wire diameter of 80 μm, Samples 7 to 12 have a wire diameter of 70 μm, Samples 13 to 18 have a wire diameter of 55 μm, Samples 19 to 24 have a wire diameter of 40 μm, and Samples 25 to 30 have a wire diameter of 30 μm.

[0060] Samples 1 to 6 have different aspect ratios, as shown in Fig. 6. Specifically, the aspect ratio of sample 1 is 0%, the aspect ratio of sample 2 is 7.5%, the aspect ratio of sample 3 is 15%, the aspect ratio of sample 4 is 23%, the aspect ratio of sample 5 is 35%, and the aspect ratio of sample 6 is 38%. Similarly, samples 7 to 12, samples 13 to 18, samples 19 to 24, and samples 25 to 30 also have different aspect ratios, as shown in Figs. 6 and 7.

[0061] The maximum diameter and orthogonal diameter (and thus the flattening ratio) of each sample can be adjusted by changing the pressing force when manufacturing the first core shaft portion having the above-mentioned cross section by pressing a wire having a circular cross section. Specifically, the greater the pressing force of the press, the greater the maximum diameter and the smaller the orthogonal diameter (and thus the greater the flattening ratio).

[0062] A-4-1-2. How to determine the maximum diameter and perpendicular diameter: The maximum diameter and the orthogonal diameter of each sample are specified, for example, as follows. First, the core shaft of each sample is cut out, and the cut surface is specified by observing the cross section with an electron microscope at a magnification of, for example, 100,000 times. In this way, the maximum diameter and the orthogonal diameter of each of a plurality of different locations (for example, 10 locations) in the first core shaft portion are calculated, and the average value of the maximum diameters of the plurality of locations is set as the maximum diameter of the first core shaft portion, and the average value of the orthogonal diameters of the plurality of locations is set as the orthogonal diameter of the first core shaft portion. Alternatively, the measurement method may be a method of irradiating the outer periphery of the core shaft of each sample with a laser or the like, extracting the outer shape of the core shaft, and calculating the maximum diameter and the orthogonal diameter, and is not particularly limited.

[0063] A-4-1-3. How to evaluate shaping directionality: FIG. 8 is an explanatory diagram for explaining a method for measuring the shaping directionality. In FIG. 8, the low flat portion 112 in the sample having the first core shaft portion 11 of this embodiment is shown in schematic form. The shaping directionality was evaluated as follows. First, as shown in FIG. 8, the tip of the first core shaft portion is curved 90° along the surface direction A (YZ surface direction in FIG. 8) along the direction of the orthogonal diameter. Next, a force is applied to the tip of the first core shaft portion along the surface direction B (XZ surface direction in FIG. 8) approximately perpendicular to the surface direction A. At this time, if the tip is curved in the surface direction A (or a surface direction closer to the surface direction A than the surface direction B), it is judged as "○" (pass), and if the tip is curved in the surface direction B (or a surface direction closer to the surface direction B than the surface direction A), it is judged as "×" (fail).

[0064] A-4-1-4. Shaping direction evaluation results: As shown in Figures 6 and 7, the evaluation results of the shaping directionality of samples 1, 7, 13, and 19 were "x". On the other hand, the evaluation results of the shaping directionality of samples 2 to 6, 8 to 12, 14 to 18, and 20 to 24 were "o". This means that by setting the flatness ratio to 7% or more, the shaping directionality tends to be limited to a specific surface direction (surface direction A along the orthogonal diameter direction).

[0065] In addition, the evaluation result of the shaping directionality of samples 25 to 30 was "x". On the other hand, as described above, the evaluation result of the shaping directionality of samples 20 to 24, etc. was "○". This means that by making the wire diameter 40 μm or more, the shaping directionality tends to be limited to a specific surface direction (surface direction A along the orthogonal diameter direction), and when the wire diameter is less than 40 μm, the shaping directionality is less likely to be limited to a specific surface direction regardless of the flattening ratio.

[0066] A-4-2. Evaluation of rotation performance: The rotation performance of the guidewire was evaluated using the 30 samples used in the evaluation of the shaping direction. Figures 9 and 10 are explanatory diagrams showing the evaluation results of the rotation performance in this embodiment. Figure 11 is an explanatory diagram showing an example of the measurement results of the rotation performance in this embodiment.

[0067] A-4-2-1. Method for evaluating rotation performance: The rotation performance was evaluated as follows: When the base end of the guidewire was rotated (circumferentially around the axis of the guidewire), the performance was evaluated based on whether the tip end of the guidewire (the first core shout portion in this performance evaluation) rotated before the base end rotated 180°.

[0068] FIG. 12 is an explanatory diagram for explaining a method for measuring rotation performance. FIG. 12 shows a state in which the guidewire 100 of this embodiment is used as a sample. Specifically, as shown in FIG. 12, a guidewire is prepared in such a state that the tip of the first core shout portion (the low flat portion 112 in the guidewire 100 of this embodiment) is bent at 90° with a curvature radius of 5 mm, and the base end portion is bent at a curvature radius of 70 mm on the opposite side to the tip portion. A motor M for rotating the guidewire (in the circumferential direction of the guidewire axis) is attached to the base end of the guidewire. Then, the motor M is driven to rotate the guidewire (in the circumferential direction of the guidewire axis). The tip of the first core shout portion (in other words, the tip of the guidewire) at this time is video-captured using a camera C, and the presence or absence of rotation of the tip of the guidewire (the first core shout portion) is determined based on the content of the video.

[0069] If the tip of the guidewire (the first core shout portion in this performance evaluation) rotates before the base end rotates 180°, it is judged as "○" (pass), and if no rotation occurs before the base end rotates 180°, it is judged as "×" (fail). Note that the smaller the radius of curvature at the tip of the first core shout portion, the greater the delay in the rotation angle of the tip portion relative to the rotation angle of the base end tends to be, so the pass / fail criteria for the evaluation of rotation performance differ depending on the radius of curvature at the tip of the first core shout portion.

[0070] A-4-2-2. Rotation performance evaluation results: As shown in Figs. 9 and 10, the evaluation results of rotation performance for Samples 1 to 4 were "○". On the other hand, the evaluation results of rotation performance for Samples 5 and 6 were "×". This means that the rotation performance of the guidewire is improved by setting the flatness ratio to less than 35%. The reason why the rotation performance of the guidewire is improved is thought to be that the occurrence of the above-mentioned whip is suppressed by having a sufficiently small flatness ratio.

[0071] FIG. 11 shows the measurement results of Samples 1, 3, and 5 as examples of the measurement results of the rotation performance of the guidewire in this performance evaluation. In Sample 1, the input rotation angle (rotation angle of the base end of the guidewire) and the output rotation angle (rotation angle of the tip end of the guidewire) have a substantially linear correspondence relationship with a slope close to 1. That is, when the base end of the guidewire is rotated, the tip end rotates at a rotation angle substantially the same as the rotation angle of the base end. Therefore, in Sample 1, the tip end of the guidewire rotates before the base end rotates 180°, so Sample 1 was judged as "○". In addition, in Sample 3, the tip end rotates before the base end rotates a rotation angle smaller than 180°, so Sample 3 was judged as "○". In addition, in Sample 5, the tip end rotates before the base end rotates a rotation angle larger than 180°, so Sample 5 was judged as "×".

[0072] In addition, the evaluation results of rotation performance were "○" for samples 7 to 30. This means that when the wire diameter is less than 80 μm, sufficient rotation performance is easily ensured regardless of the flattening ratio, and the above-mentioned problems regarding rotation performance are likely to occur when the wire diameter is 80 μm or more.

[0073] The results of performance evaluation (evaluation of shaping directionality and rotation performance) in second to fourth embodiments and modified examples described below are similar to the results of performance evaluation in the first embodiment.

[0074] B. Second embodiment: B-1. Configuration of guidewire 100A: Fig. 13 is a side view showing a schematic overall configuration of a guidewire 100A in a second embodiment. Fig. 13 shows the overall configuration of the guidewire 100A as viewed in the positive X-axis direction. Fig. 14 is an enlarged side view of a portion of a core shaft 10A in a second embodiment. Fig. 14 shows the configuration of a portion of the core shaft 10A (portion X2 in Fig. 13) as viewed in the positive X-axis direction. Fig. 15 is a cross-sectional view showing the cross-sectional configuration of the core shaft 10A at a position XV-XV in Fig. 14. Fig. 15 shows the cross-sectional configuration of the core shaft 10A as viewed in the negative Z-axis direction.

[0075] 13 and 14, the configuration of guidewire 100A of the second embodiment is different from the configuration of guidewire 100 of the above-mentioned first embodiment in the shape of first core shaft portion 11A. In the following, among the configuration of guidewire 100A of the second embodiment, the same configuration as the configuration of guidewire 100 of the above-mentioned first embodiment is denoted by the same reference numerals and description thereof will be omitted as appropriate.

[0076] As shown in Figures 13 and 14, the core shaft 10A of the second embodiment has a first core shaft portion 11A including the tip of the core shaft 10A, and a second core shaft portion 12 located on the base end side of the core shaft 10A relative to the first core shaft portion 11A.

[0077] 15, the cross section (XY cross section in this embodiment) of the first core shaft portion 11A has a flattened shape (approximately rectangular or elliptical) with the diameter in the X-axis direction as the major axis and the diameter in the Y-axis direction as the minor axis. In the cross section of the first core shaft portion 11A, the major axis corresponds to the maximum diameter D31 (the diameter having the maximum length in the cross section (XY cross section in this embodiment) perpendicular to the axial direction of the core shaft 10A), and the minor axis corresponds to the orthogonal diameter D32 (the diameter having the maximum length in the direction perpendicular to the maximum diameter in the cross section perpendicular to the axial direction of the core shaft 10A).

[0078] The first core shaft portion 11A of the second embodiment is a rod-shaped member. The flattening ratio of the first core shaft portion 11A is 7% or more and 35% or less. As a specific example, when the wire diameter of the first core shaft portion 11A is 40 μm, if the flattening ratio is 30.0%, the maximum diameter D31 is 46 μm and the orthogonal diameter D32 is 32 μm. If the flattening ratio is 7.3%, the maximum diameter D31 is 41 μm and the orthogonal diameter D32 is 38 μm. The flattening ratio of the first core shaft portion 11A may be another value that is 7% or more and 35% or less. The maximum diameter D31 and the orthogonal diameter D32 when the wire diameter is changed are the same as those described in the first embodiment. The first core shaft portion 11A of this embodiment is an example of the first specific portion of the claims.

[0079] The cross-sectional shape of the first core shaft portion 11A in the second embodiment is uniform over the entire length in the axial direction (the Z-axis direction in this embodiment) of the first core shaft portion 11A.

[0080] B-2. Advantages of the second embodiment: As described above, the guidewire 100A of the second embodiment includes the core shaft 10A. The core shaft 10A has a first core shaft portion 11A located at the distal end side of the core shaft 10A and having a flattening ratio of 7% or more and 35% or less. The length of the first core shaft portion 11A in the axial direction of the core shaft 10A (in this embodiment, the Z-axis direction) is 5 mm or more.

[0081] In the guidewire 100A of the second embodiment, as described above, the flattening ratio of the first core shaft portion 11A is 7% or more and 35% or less. Therefore, in the guidewire 100A of the second embodiment, compared to a configuration in which the cross section of the first core shaft portion 11A is circular, the bending direction of the first core shaft portion 11A during shaping tends to be limited to a specific planar direction (specifically, a direction along a plane along the axial direction and the direction of the orthogonal diameter D32 of the core shaft 10A (in this embodiment, the YZ plane)). Therefore, according to the guidewire 100A of the second embodiment, the first core shaft portion 11A can be easily bent in a specific planar direction (or a direction close to the specific planar direction) during shaping. Furthermore, in the guidewire 100A of the second embodiment, the flattening ratio of the first core shaft portion 11A is less than 35% as described above. Therefore, according to the guidewire 100A of the second embodiment, while the first core shaft portion 11A can be easily bent in a specific planar direction during shaping as described above, the rotational performance of the guidewire 100A can be ensured for the same reasons as in the first embodiment.

[0082] In a configuration in which the length of the first core shaft portion 11A in the axial direction of the core shaft 10A is less than 5 mm, it is difficult to shape the tip portion, but in this embodiment, the length of the first core shaft portion 11A in the axial direction of the core shaft 10A is 5 mm or more, which makes it easier to shape the tip portion. If the length of the first core shaft portion 11A in the axial direction of the core shaft 10A is excessively long, whip may easily occur, so the length of the first core shaft portion 11A in the axial direction of the core shaft 10A is preferably, for example, 15 mm or less.

[0083] In the guidewire 100A of the second embodiment, the first core shaft portion 11A is made of a material containing stainless steel. Therefore, in the guidewire 100A of the second embodiment, the first core shaft portion 11A is made of a material containing stainless steel that is easily plastically deformed, and deformation due to shaping tends to remain without returning to its original shape, making shaping easy to perform.

[0084] Furthermore, in the guidewire 100A of the second embodiment, the core shaft 10A is located closer to the base end of the guidewire 100A than the first core shaft portion 11A and has a second core shaft portion 12 formed of a material containing a superelastic alloy. Therefore, according to the guidewire 100A of the second embodiment, while the first core shaft portion 11A can be easily bent in a specific plane direction during shaping as described above, the operability and blood vessel selectivity of the guidewire 100A can be ensured for the same reasons as in the first embodiment.

[0085] C. Third embodiment: C-1. Configuration of guidewire 100B: Fig. 16 is a side view showing a schematic overall configuration of a guidewire 100B in the third embodiment. Fig. 17 is a cross-sectional view showing a cross-sectional configuration of a core shaft 10B at a position XV-XV in Fig. 16. Fig. 18 is a cross-sectional view showing a cross-sectional configuration of a core shaft 10B at a position XVIII-XVIII in Fig. 16. The configuration of the guidewire 100B in the third embodiment is different from the configuration of the guidewire 100 in the first embodiment described above in that the configuration of the core shaft 10B is different. In the following, the configuration of the guidewire 100A in the second embodiment that is the same as the configuration of the guidewire 100 in the first embodiment described above is denoted by the same reference numerals and the description thereof will be omitted as appropriate.

[0086] As shown in Fig. 16, the core shaft 10B of the third embodiment is a rod-shaped member having a small diameter at the tip end side and a large diameter at the base end side. The core shaft 10B includes a first core shaft portion 11B including the tip end of the core shaft 10B, and a second core shaft portion 12 located on the base end side of the core shaft 10B with respect to the first core shaft portion 11B. The core shaft 10B is formed by integrally forming the first core shaft portion 11B and the second core shaft portion 12. In this embodiment, the core shaft 10B is formed of a material including stainless steel (SUS302, SUS304, SUS316, etc.).

[0087] As shown in Figures 17 and 18, the first core shaft portion 11B has a high flat portion 110B, a tapered portion 111B, and a low flat portion 112B having a cross-section having a shape similar to that of the high flat portion 110, the tapered portion 111, and the low flat portion 112 of the first core shaft portion 11 in the first embodiment.

[0088] C-2. Advantages of the third embodiment: The guidewire 100B of the third embodiment includes a core shaft 10B. The core shaft 10B has a low flattened portion 112B (of the first core shaft portion 11B) located at the distal end side of the core shaft 10B and having a flattening ratio of 7% or more and 35% or less. The length of the low flattened portion 112B of the first core shaft portion 11B in the axial direction of the core shaft 10B (in this embodiment, the Z-axis direction) is 5 mm or more.

[0089] Therefore, according to the third embodiment of the guidewire 100B, for the same reasons as in the first embodiment, the low flat portion 112B of the first core shaft portion 11B can be easily bent in a specific planar direction during shaping, while still ensuring the rotational performance of the guidewire 100B.

[0090] In the guidewire 100B of the third embodiment, the wire diameter of the low flat portion 112B of the first core shaft portion 11B is 40 μm or more. Therefore, according to this embodiment, for the same reason as in the first embodiment, the rotation performance of the guidewire 100B can be more reliably ensured.

[0091] In the guidewire 100B of the third embodiment, the maximum diameter D51 (or the wire diameter) of the low flattened portion 112 of the first core shaft portion 11B is 80 μm or more.

[0092] In the guidewire 100B of the third embodiment, the low flat portion 112B of the first core shaft portion 11B is made of a material containing stainless steel. Therefore, in the guidewire 100B of the third embodiment, the low flat portion 112B of the first core shaft portion 11B is made of a material containing stainless steel that is easily plastically deformed, and deformation due to shaping tends to remain without returning to its original shape, making shaping easy.

[0093] In the guidewire 100B of the third embodiment, the core shaft 10B has a high flat portion 110B (of the first core shaft portion 11B) that is located closer to the tip of the core shaft 10B than the low flat portion 112B of the first core shaft portion 11B and has a flattening ratio of 40% or more. Therefore, for the same reasons as in the first embodiment, the guidewire 100B of the third embodiment is particularly suitable for use when the guidewire 100B is used in a state in which the low flat portion 112B of the first core shaft portion 11B is bent relatively slightly and the high flat portion 110B located closer to the tip than the high flat portion 110B is bent relatively greatly.

[0094] In the guidewire 100B of the third embodiment, the direction of the maximum diameter D51 of the low flat portion 112B of the first core shaft portion 11B and the direction of the maximum diameter D51 of the high flat portion 110B of the first core shaft portion 11B are parallel to each other. Therefore, for the same reason as in the first embodiment, the directionality of deformation of the guidewire 100B due to shaping can be limited to a specific planar direction (or a direction close to the specific planar direction).

[0095] In the guidewire 100B of the third embodiment, the highly flattened portion 110B of the first core shaft portion 11B is made of a material containing stainless steel. Therefore, in the guidewire 100B of the third embodiment, the highly flattened portion 110B of the first core shaft portion 11B is made of a material containing stainless steel that is easily plastically deformed, and deformation due to shaping tends to remain without returning to its original shape, making shaping easy to perform.

[0096] D. Fourth embodiment: D-1. Configuration of guidewire 100C: Fig. 19 is a side view showing a schematic overall configuration of a guidewire 100C in a fourth embodiment. Fig. 20 is a cross-sectional view showing a cross-sectional configuration of a core shaft 10C taken along the line XX-XX in Fig. 19. The configuration of the guidewire 100C in the fourth embodiment is different from the configuration of the guidewire 100A in the second embodiment described above in that the configuration of the core shaft 10C is different. In the following, the configuration of the guidewire 100A in the second embodiment that is the same as the configuration of the guidewire 100A in the second embodiment described above will be denoted by the same reference numerals and description thereof will be omitted as appropriate.

[0097] As shown in Fig. 19, the core shaft 10C of the fourth embodiment is a rod-shaped member having a small diameter at the tip end side and a large diameter at the base end side. The core shaft 10C of the fourth embodiment includes a first core shaft portion 11C including the tip end of the core shaft 10C, and a second core shaft portion 12 located on the base end side of the core shaft 10C with respect to the first core shaft portion 11C. The core shaft 10C is formed by integrally forming the first core shaft portion 11C and the second core shaft portion 12C. In this embodiment, the core shaft 10C is formed of a material including stainless steel (SUS302, SUS304, SUS316, etc.).

[0098] As shown in FIG. 20, the first core shaft portion 11C has a cross section having a shape similar to that of the first core shaft portion 11A in the second embodiment.

[0099] D-2. Advantages of the fourth embodiment: The guidewire 100C of the fourth embodiment includes a core shaft 10C. The core shaft 10C has a first core shaft portion 11C located at the distal end side of the core shaft 10C and having a flattening ratio of 7% or more and 35% or less. The length of the first core shaft portion 11C in the axial direction of the core shaft 10C (in this embodiment, the Z-axis direction) is 5 mm or more.

[0100] In the guidewire 100C of the fourth embodiment, as described above, the flattening ratio of the first core shaft portion 11C is not less than 7% and not more than 35%. Therefore, according to the guidewire 100C of the fourth embodiment, for the same reasons as in the second embodiment and the first embodiment, the first core shaft portion 11C can be easily bent in a specific planar direction during shaping, while the rotation performance of the guidewire 100C can be ensured for the same reasons as in the second embodiment and the first embodiment.

[0101] Furthermore, in the guidewire 100C of the fourth embodiment, the first core shaft portion 11C is made of a material containing stainless steel. Therefore, in the guidewire 100C of the fourth embodiment, the first core shaft portion 11C is made of a material containing stainless steel that is easily plastically deformed, and deformation due to shaping tends to remain without returning to its original shape, making shaping easy to perform.

[0102] E. Variations: The technology disclosed in this specification is not limited to the above-described embodiments, and can be modified in various forms without departing from the spirit of the invention. For example, the following modifications are also possible.

[0103] The configurations of the guidewires 100, 100A in the above-described embodiments are merely examples and can be modified in various ways.

[0104] For example, in the above first embodiment, the direction of the maximum diameter D21 of the low flat portion 112 of the first core shaft portion 11 and the direction of the maximum diameter D11 of the high flat portion 110 of the first core shaft portion 11 may not be parallel to each other.

[0105] In the above-described embodiments, the guidewires 100, 100A, 100B, and 100C may not necessarily include the distal joint portion 30.

[0106] Furthermore, the materials of the members constituting the guidewires 100, 100A, 100B, and 100C in the above-described embodiments are merely examples and can be modified in various ways.

[0107] The technology disclosed in this specification can be realized, for example, in the following forms. [Form 1] A guidewire comprising a core shaft, The diameter at which the length is maximum in a cross section perpendicular to the axial direction of the core shaft is defined as the maximum diameter, the diameter in the cross section perpendicular to the direction of the maximum diameter is defined as the orthogonal diameter, and the flattening ratio is the difference between the maximum diameter and the orthogonal diameter divided by the maximum diameter. the core shaft has a first specific portion located on a tip side of the core shaft, the first specific portion having an aspect ratio of 7% or more and 35% or less; The first specific portion in the axial direction is 5 mm or more. Guidewire. [Form 2] The guidewire according to aspect 1, The first specific portion is formed of a material including stainless steel. Guidewire. [Form 3] The guidewire according to aspect 1 or 2, The core shaft has a second specific portion located closer to the tip end of the core shaft than the first specific portion, and the flattening ratio is 40% or more. Guidewire. [Form 4] The guidewire according to aspect 3, The direction of the maximum diameter of the first specific portion and the direction of the maximum diameter of the second specific portion are parallel to each other. Guidewire. [Form 5] The guidewire according to aspect 3 or 4, The second specific portion is formed of a material including stainless steel. Guidewire. [Form 6] The guidewire according to any one of the first to fifth aspects, The core shaft has a superelastic portion located on the proximal end side of the guide wire relative to the first specific portion and formed of a material including a superelastic alloy. Guidewire. [Explanation of symbols]

[0108] 10: Core shaft (first embodiment) 10A: Core shaft (second embodiment) 10B: Core shaft (third embodiment) 10C: Core shaft (fourth embodiment) 11: First core shaft portion (first embodiment) 11A: First core shaft portion (of the second embodiment) 11B: First core shaft part (of the third embodiment) 11C: First core shaft part (of the fourth embodiment) 12: Second core shaft section 20: Coil body 30: Distal joint 40: Proximal junction 100: Guidewire (first embodiment) 100A: Guidewire (second embodiment) 100B: Guidewire (third embodiment) 100C: Guidewire (fourth embodiment) 110: High flat portion of the first core shaft portion (first embodiment) 110B: Highly flattened portion of the first core shaft portion (of the third embodiment) 111: Tapered portion of the first core shaft portion (of the first embodiment) 111B: Tapered portion of the first core shaft portion (of the third embodiment) 112: Low flat portion of the first core shaft portion (first embodiment) 112B: Low flat portion of the first core shaft portion (of the third embodiment) 120: Thin-diameter portion of second core shaft 121: thick-diameter part of second core shaft 122: Tapered portion of second core shaft portion

Claims

1. A guide wire comprising a core shaft, wherein the core shaft has a flat portion formed by subjecting a rod-shaped member having a circular cross-section and a wire diameter of 40 μm or more to pressing, in the flat portion, when the diameter having the maximum length in a cross-section orthogonal to the axial direction of the core shaft is defined as the major diameter, the diameter having the maximum length in a direction orthogonal to the major diameter direction in the cross-section is defined as the orthogonal diameter, and the value obtained by dividing the difference between the major diameter and the orthogonal diameter by the major diameter is defined as the flatness ratio, the core shaft has a first specific portion located on the tip side of the core shaft and having a flatness ratio of 7.5% or more and 35% or less, and a tapered portion adjacent to the first specific portion and having a gradually changing flatness ratio, the first specific portion is formed of a material containing stainless steel, a guide wire.

2. A guide wire comprising a core shaft, wherein the core shaft has a flat portion formed by subjecting a rod-shaped member having a circular cross-section and a wire diameter of 40 μm or more to pressing, in the flat portion, when the diameter having the maximum length in a cross-section orthogonal to the axial direction of the core shaft is defined as the major diameter, the diameter having the maximum length in a direction orthogonal to the major diameter direction in the cross-section is defined as the orthogonal diameter, and the value obtained by dividing the difference between the major diameter and the orthogonal diameter by the major diameter is defined as the flatness ratio, the core shaft has a first specific portion located on the tip side of the core shaft and having a flatness ratio of 7.5% or more and 35% or less, and a tapered portion adjacent to the tip side of the first specific portion and having a gradually changing flatness ratio, a guide wire.

3. The guide wire according to Claim 2, wherein the first specific portion is formed of a material containing stainless steel, a guide wire.

4. The guide wire according to any one of Claims 1 to 3, wherein the contour of the cross-section of the first specific portion includes an arc, a guide wire.

5. The guide wire according to any one of Claims 1 to 4, wherein the contour of the cross-section of the first specific portion includes two parallel lines, a guide wire.

6. The guide wire according to any one of Claims 1 to 5, wherein the cross-section of the first specific portion is substantially elliptical, a guide wire.

7. A guide wire according to any one of Claims 1 to 6, wherein the core shaft is located on the proximal end side of the guide wire rather than the first specific part and has a superelastic part formed of a material containing a superelastic alloy. Guide wire.

8. A guide wire according to any one of Claims 1 to 7, wherein a coil body; and a distal end side joint that joins the distal end of the core shaft and the distal end of the coil body, and further comprises a guide wire (however, excluding the case where there is a reinforcing part that reinforces the first specific part on the proximal end side of the proximal end of the distal end side joint and is provided on the surface of the first specific part).

9. A guide wire according to any one of Claims 1 to 7, wherein it further comprises a coil body, and in the coil body, the part covering the first specific part has adjacent strands of the coil body separated from each other. Guide wire.

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