guide wire

Abstract

An injured body lumen wall is inhibited from being penetrated, and a decrease in a penetration performance is inhibited. A guide wire includes: a core shaft; and a tubular body disposed so as to surround an outer periphery of a front end side portion of the core shaft. The tubular body has: a first tubular portion; and a second tubular portion located closer to a base end side of the tubular body than the first tubular portion. A maximum dimension of an outer shape of a cross section of the second tubular portion is larger than a maximum dimension of an outer shape of a cross section of the first tubular portion, and a minimum dimension of the outer shape of the cross section of the second tubular portion is smaller than a minimum dimension of the outer shape of the cross section of the first tubular portion.

Description

Technical Field

[0001] The technology disclosed in this specification relates to a guidewire for guiding medical devices to a target location within a body cavity. Background Technology

[0002] The use of catheters is widely practiced as a method for treating or examining narrowed or occluded portions (hereinafter referred to as "lesions") within body cavities (such as blood vessels). Typically, a guidewire is used to guide the catheter into the lesion within the body cavity. The guidewire comprises a mandrel and a coil body arranged to surround the outer periphery of the mandrel. In existing guidewires, the cross-sectional shape of the coil body is the same along its entire length (e.g., circular or elliptical) (see, for example, Patent Documents 1-3).

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2015-171519

[0006] Patent Document 2: Japanese Patent Application Publication No. 2013-176488

[0007] Patent Document 3: Japanese Patent Application Publication No. 09-56822 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] Guidewires require high penetration performance, such as the ability to reliably penetrate relatively hard lesions, including those known as chronic total occlusion (CTO). However, excessively high penetration performance can increase the likelihood of accidental injury to body cavity walls (such as blood vessels). Previously, no structures were proposed in guidewires designed to inhibit damage to body cavity walls and prevent a decrease in penetration performance.

[0010] It should be noted that this problem is not limited to guide wires in which the coil body is arranged to surround the outer periphery of the core shaft. It is a common problem in guide wires in cylindrical bodies other than the coil body (such as tubes with slits) in which the outer periphery of the core shaft is arranged to surround the core shaft.

[0011] This specification discloses a technique that can solve at least a portion of the above-mentioned problems.

[0012] Methods for solving problems

[0013] The techniques disclosed in this specification can be implemented, for example, in the following ways.

[0014] (1) The guidewire disclosed in this specification comprises: a mandrel; and a cylindrical body, the cylindrical body being arranged to surround the outer periphery of the front end portion of the mandrel, the cylindrical body having: a first cylindrical portion; and a second cylindrical portion, the second cylindrical portion being located closer to the base end of the cylindrical body than the first cylindrical portion, the maximum dimension of the cross-sectional shape of the second cylindrical portion being greater than the maximum dimension of the cross-sectional shape of the first cylindrical portion, and the minimum dimension of the cross-sectional shape of the second cylindrical portion being less than the minimum dimension of the cross-sectional shape of the first cylindrical portion. Hereinafter, such dimensional relationship is referred to as the "prescribed dimensional relationship of the cylindrical body".

[0015] During the passage of the guidewire through a lesion, for example, within a body cavity, the first tubular portion of the guidewire enters the lesion, followed by the second tubular portion. Here, the maximum dimension of the cross-sectional area of ​​the second tubular portion is greater than the maximum dimension of the cross-sectional area of ​​the first tubular portion. Therefore, as the second tubular portion of the guidewire begins to enter the lesion or vessel wall, the insertion resistance increases according to the difference in maximum dimensions between the first and second tubular portions. The surgeon can, for example, carefully insert the guidewire 100 based on the guidewire configuration and the changes in insertion resistance observed in X-ray fluoroscopy images during the procedure, thus, for example, preventing damage to the blood vessel.

[0016] Furthermore, in this guidewire, the minimum dimension of the cross-sectional shape of the second cylindrical portion is smaller than the minimum dimension of the cross-sectional shape of the first cylindrical portion. Therefore, compared to structures where the minimum dimension of the cross-sectional shape of the second cylindrical portion is greater than or equal to the minimum dimension of the cross-sectional shape of the first cylindrical portion, the smaller cross-sectional area of ​​the second cylindrical portion correspondingly suppresses a decrease in the guidewire's penetration performance. Thus, with this guidewire, damage to the body cavity wall can be suppressed, and a decrease in penetration performance can be prevented.

[0017] (2) In the above-described guidewire, the cylindrical body may also be configured such that it has a third cylindrical portion located closer to the base end of the cylindrical body than the second cylindrical portion, and the maximum dimension of the cross-sectional shape of the third cylindrical portion is smaller than the maximum dimension of the cross-sectional shape of the second cylindrical portion. With this guidewire, for example, compared to a structure where the maximum dimension of the cross-sectional shape of the third cylindrical portion is greater than or equal to the maximum dimension of the cross-sectional shape of the second cylindrical portion, excessive insertion resistance as a whole can be suppressed. Specifically, excessive insertion resistance when inserting into the lesion within the third cylindrical portion can be suppressed.

[0018] (3) In the above-described guidewire, the maximum dimension of the cross-sectional shape of the third cylindrical portion may be closer to the maximum dimension of the cross-sectional shape of the first cylindrical portion than the maximum dimension of the cross-sectional shape of the second cylindrical portion, and the minimum dimension of the cross-sectional shape of the third cylindrical portion may be closer to the minimum dimension of the cross-sectional shape of the first cylindrical portion than the minimum dimension of the cross-sectional shape of the second cylindrical portion. With this guidewire, for example, compared to a structure where the maximum and minimum dimensions of the cross-sectional shape of the third cylindrical portion are close to the maximum and minimum dimensions of the cross-sectional shape of the second cylindrical portion, excessive insertion resistance as a whole can be suppressed more effectively. Specifically, excessive insertion resistance when inserting into the lesion within the third cylindrical portion can be suppressed more effectively.

[0019] (4) In the above-described guidewire, the first cylindrical portion may have a circular cross-section, and the second cylindrical portion may have an oblong cross-section. With this guidewire, the portion whose cross-section is made oblong by applying mechanical force to the cylindrical member is the second cylindrical portion, and the portion whose cross-section is circular without such mechanical force is the first cylindrical portion. This allows for easy acquisition of a guidewire that satisfies the aforementioned "prescribed dimensional relationship of the cylindrical body." Furthermore, with this guidewire, for example, compared to a structure where the cross-section of the first cylindrical portion is also oblong, a smoother rotational operation of the guidewire tip is possible.

[0020] (5) In the above-described guidewire, the mandrel and the cylindrical body may also be bent at the second cylindrical portion. This guidewire can improve cavity selectivity and suppress damage to the cavity wall as well as reduce penetration performance.

[0021] (6) In the above-mentioned guidewire, the cylindrical body may also be configured as a coil body, wherein the coil body has a structure in which one or more wires are wound into a spiral shape. With this guidewire, for a guidewire having a coil body, damage to the cavity wall can be suppressed, and the reduction in penetration performance can be suppressed.

[0022] (7) In the above-mentioned guide wire, the wire material may also be a single wire or a stranded wire. With this guide wire, for a coil body having a single wire or a stranded wire material, damage to the cavity wall can be suppressed, and the reduction in penetration performance can be suppressed.

[0023] (8) In the above-described guide wire, it is also possible to configure the wire such that adjacent portions along the length of the coil body are in contact with each other. With this guide wire, the second cylindrical portion can be easily manufactured by applying mechanical force to the coil body.

[0024] (9) In the above-mentioned guidewire, the cylindrical body may also be configured as a tube with a slit. With this guidewire, for a guidewire having a tube with a slit, damage to the body cavity wall can be suppressed, and the reduction in penetration performance can be suppressed.

[0025] (10) In the above-described guidewire, it may also be configured to have an inner cylindrical body, which is housed within at least the second cylindrical portion of the cylindrical body and arranged to surround at least a portion of the front end side portion of the mandrel. This guidewire improves torque transmission. Specifically, it enables sufficient transmission of the force applied to the base end side of the guidewire in the rotational direction to the front end side.

[0026] (11) In the above-described guidewire, the inner cylindrical body may also be configured to have: a first inner cylindrical portion; and a second inner cylindrical portion, wherein the second inner cylindrical portion is located closer to the base end of the inner cylindrical body than the first inner cylindrical portion, and the maximum dimension of the cross-sectional shape of the second inner cylindrical portion is greater than the maximum dimension of the cross-sectional shape of the first inner cylindrical portion, and the minimum dimension of the cross-sectional shape of the second inner cylindrical portion is smaller than the minimum dimension of the cross-sectional shape of the first cylindrical portion. Hereinafter, such a dimensional relationship will be referred to as the "prescribed dimensional relationship of the inner cylindrical body". With this guidewire, when the mandrel is rotated, the second cylindrical portion and the second inner cylindrical portion, which are non-circular to each other, engage with each other, becoming a single unit and easily rotated, thus further improving the torque transmission performance of the guidewire.

[0027] (12) In the above-described guidewire, the cross-sectional shape of the first inner cylindrical portion may be circular, and the cross-sectional shape of the second inner cylindrical portion may be oblong. With this guidewire, the portion whose cross-section becomes oblong by applying mechanical force to the cylindrical member is designated as the second inner cylindrical portion, and the portion whose cross-section is circular without such mechanical force is designated as the first inner cylindrical portion. Thus, a guidewire that satisfies the aforementioned "prescribed dimensional relationship of the inner cylindrical body" can be easily obtained. Furthermore, assuming that the cross-sectional shape of the first inner cylindrical portion is also oblong, since the first inner cylindrical portion is prone to bending in the direction of the short axis of the cross-section but difficult to bend in the direction of the long axis, the bending direction of the first inner cylindrical portion is limited to a predetermined direction. As a result, for example, it may lead to a decrease in vascular selectivity. In contrast, with this guidewire, since the cross-sectional shape of the first inner cylindrical portion is circular, the bending direction of the first inner cylindrical portion is not limited, for example, it is possible to suppress a decrease in vascular selectivity.

[0028] (13) In the above-described guidewire, the inner cylindrical body may also be configured such that: a first inner cylindrical portion; and a second inner cylindrical portion, the second inner cylindrical portion being located closer to the base end of the inner cylindrical body than the first inner cylindrical portion, and the second cylindrical portion of the cylindrical body and the second inner cylindrical portion of the inner cylindrical body are in contact with each other. With this guidewire, when the mandrel is rotated, the second cylindrical portion and the second inner cylindrical portion become one unit due to the frictional resistance generated between them and can be easily rotated, thus further improving the torque transmission performance of the guidewire.

[0029] (14) In the above-described guidewire, the inner cylindrical body may also be configured to have: a first inner cylindrical portion; and a second inner cylindrical portion, wherein the second inner cylindrical portion is located closer to the base end of the inner cylindrical body than the first inner cylindrical portion, and the second inner cylindrical portion of the inner cylindrical body is in contact with the mandrel. With this guidewire, when the mandrel 10 is rotated, the second inner cylindrical portion and the mandrel become an integral unit due to the frictional resistance generated between them, making rotation easier, thus further improving the torque transmission performance of the guidewire.

[0030] It should be noted that the technology disclosed in this specification can be implemented in various ways, such as by means of a guidewire or its manufacturing method. Attached Figure Description

[0031] Figure 1 This is an explanatory diagram that schematically shows the structure of the guidewire in the first embodiment.

[0032] Figure 2 This is an explanatory diagram showing the external structure of the front end of the guidewire.

[0033] Figure 3 This is an explanatory diagram showing the cross-sectional structure of the tip of the guidewire.

[0034] Figure 4 This is an explanatory diagram that schematically shows the structure of the guidewire in the second embodiment.

[0035] Figure 5 This is an explanatory diagram showing the cross-sectional structure of the tip of the guidewire.

[0036] Figure 6 This is an explanatory diagram showing the cross-sectional structure of the front end of the guide wire in a modified example 1 of the first embodiment.

[0037] Figure 7 This is an explanatory diagram showing the cross-sectional structure of the front end of the guide wire in a modified example 2 of the first embodiment.

[0038] Figure 8This is an explanatory diagram showing the cross-sectional structure of the front end of the guide wire in a variation 3 of the first embodiment.

[0039] Figure 9 This is an explanatory diagram showing the cross-sectional structure of the front end of the guide wire in Variation 4 of the first embodiment.

[0040] Figure 10 This is an explanatory diagram showing the cross-sectional structure of the front end of the guide wire in Variation 5 of the first embodiment. Detailed Implementation

[0041] A. First implementation method:

[0042] A-1. Structure of the guidewire:

[0043] Figure 1 This is an explanatory diagram that schematically shows the structure of the guidewire 100 in the first embodiment. Figure 1 The mutually orthogonal XYZ axes used to determine direction are shown. The overall structure of the guidewire 100 when viewed in the positive X-axis direction is shown. The longitudinal section structure with respect to the coil body 20 and the front end joint 30 (described later) is shown. The longitudinal section refers to a section parallel to the axial direction of the guidewire 100 (in this embodiment, the YZ section). Figure 1 In this context, the positive Z-axis side is the distal end (the side inserted into the body), while the negative Z-axis side is the proximal end (the side operated on by the surgeon). This also applies to... Figure 2 The accompanying figures show the guidewire 100, which has a degree of flexibility capable of bending. It should be noted that, in the following text, the portion including the front end and extending from the front end toward the base end towards the middle of the guidewire 100 and its structural members will be referred to as the "front end portion". Similarly, the portion including the base end and extending from the base end toward the front end towards the middle of the guidewire 100 and its structural members will be referred to as the "base end portion".

[0044] Guidewire 100 is, for example, a long, thin medical device designed to penetrate hard lesions (e.g., CTO) within a blood vessel, capable of being inserted into the vessel, and flexible. The total length of guidewire 100 is, for example, between 1500 mm and 2000 mm.

[0045] The guide wire 100 includes a spindle 10, a coil body 20, a front end side joint 30, a base end side joint 32, and an inner coil body 40.

[0046] The mandrel 10 comprises a coarse-diameter portion 13, a fine-diameter portion 11, and a tapered portion 12. The coarse-diameter portion 13 has a substantially fixed outer diameter. The fine-diameter portion 11 is located closer to the front end of the coarse-diameter portion 13 and has a substantially fixed outer diameter smaller than that of the coarse-diameter portion 13. The tapered portion 12 is located between the coarse-diameter portion 13 and the fine-diameter portion 11, and its outer diameter gradually decreases from the boundary with the coarse-diameter portion 13 towards the boundary with the fine-diameter portion 11. The cross-sectional shape of each position of the mandrel 10 can be arbitrary, such as circular or flat. The cross-section refers to the section orthogonal to the axial direction of the guide wire 100 (in the case of axial bending of the guide wire 100, the section orthogonal to the tangent of that axis). The outer diameter of the coarse-diameter portion 13 is, for example, about 0.2 mm or more and about 0.8 mm or less, and the outer diameter of the fine-diameter portion 11 is, for example, about 0.05 mm or more and about 0.3 mm or less.

[0047] The materials used to form the mandrel 10 can be, for example, stainless steel (SUS302, SUS304, SUS316, etc.), super-elastic alloys such as Ni-Ti alloy, piano wire, etc. The mandrel 10 can be formed entirely of the same material, or each part can be formed of different materials.

[0048] The coil body 20 has a structure in which multiple (e.g., 8) wires are wound into a spiral shape. The number of wires in the coil body 20 can be one or more. When the coil body 20 is composed of multiple wires, the number of wires can be set, for example, in the range of 2 to 20. The coil body 20 is an example of the cylindrical body in the claims.

[0049] The coil body 20 comprises eight strands, namely stranded wires 22a, 22b, 22c, 22d, 22e, 22f, 22g, and 22h. In the stranded wires (an example of the wires in the coil body 20) 22a, 22b, 22c, 22d, 22e, 22f, 22g, and 22h, adjacent portions are in contact with each other along the length of the coil body 20. For example, adjacent stranded wire portions 22a and 22b along the length of the coil body 20 are in contact with each other. Similarly, adjacent stranded wire portions 22b and 22c, 22c and 22d, 22d and 22e, 22e and 22f, 22f and 22g, 22g and 22h, and 22h and 22a are in contact with each other. The coil body 20 may have a structure in which one or more wires are wound without gaps along the length of the coil body 20 (tight winding structure).

[0050] Each of the above-mentioned stranded wires, such as stranded wire 22c, has a structure formed by twisting together one core wire (single wire) 24 and six side wires (single wires) 26. Figure 1The area shown in X1 is an enlarged view of the cross-sectional structure of the stranded wire used as the coil body 20, for example, an enlarged view of the cross-sectional structure of stranded wire 22c. The wire used as the coil body 20 can be a single wire or a stranded wire. When the coil body 20 is composed of multiple wires, a single wire can be used as at least one of the multiple wires, and stranded wires can be used as the remaining wires.

[0051] It should be noted that, in Figure 1 In this context, the shape of the cross-section of the wire in the coil body 20, such as the stranded wire 22c, or the respective cross-sections of the core wire 24 and side wires 26 of the stranded wire 22c, is generally described as circular. Similarly, in Figures 3-5 In the description, the shape of the wire, core wire, and side wires of the coil body 20 is also generally described as circular. In reality, the wire of the coil body 20, such as stranded wire 22c, is wound into a spiral shape together with other wires, and along a path relative to... Figure 1 The strand 22c extends in a direction perpendicular to the paper (Z-axis direction) and the side wire 26 of the stranded wire 22c extends in a direction inclined relative to the core wire 24. Therefore, the cross-sectional shape of the stranded wire 22c, the core wire 24 and the side wire 26 is actually different from a circle (e.g., oblong).

[0052] The coil body 20 is disposed around the mandrel 10 in such a way that it covers the mandrel 10. In this embodiment, the coil body 20 covers the narrow diameter portion 11 and the tapered portion 12 of the mandrel 10. The narrow diameter portion 11 and the tapered portion 12 are examples of the front end side portion of the mandrel as described in the claims.

[0053] As the material for forming the coil body 20, for example, metallic materials can be used. More specifically, materials such as stainless steel (SUS302, SUS304, SUS316, etc.), piano wire, Ni-Ti alloys, or other highly elastic alloys can be used, or materials that are not radiolucent, such as platinum, gold, tungsten, or their alloys. The coil body 20 can be formed entirely of the same material, or each part can be formed of different materials.

[0054] The front-end joint 30 is a component that joins the front end of the coil body 20 to the front end of the mandrel 10. That is, the front end of the coil body 20 and the front end of the mandrel 10 are fixed by being embedded inside the front-end joint 30. The base-end joint 32 is a component that joins the base end of the coil body 20 to the mandrel 10. Materials used to form the front-end joint 30 and the base-end joint 32 include, for example, brazing filler metals (Au-Sn alloy, Sn-Ag alloy, Sn-Pb alloy, Pb-Ag alloy, etc.), solders (aluminum alloy solder, silver solder, gold solder, etc.), and adhesives (epoxy adhesives, etc.). The materials used to form the front-end joint 30 and the base-end joint 32 can be the same or different. Furthermore, the front-end joint 30 and the base-end joint can be entirely formed of the same material, or each part can be formed of different materials.

[0055] An inner coil body 40 is provided between the coil body 20 and the mandrel 10. The inner coil body 40 is housed in the second cylindrical portion L2 (described later) and is arranged to surround a portion of the front end side of the mandrel 10. The front end of the inner coil body 40 engages with the front end side joint 30, and the base end of the inner coil body 40 engages with the narrow diameter portion 11 of the mandrel 10 via the base end side joint (not shown). The inner coil body 40 is an example of the inner cylindrical body in the claims.

[0056] The inner coil body 40 is a coil-shaped component formed by winding one or more wires into a spiral shape to create a hollow shape. As... Figure 1 The inner coil body 40 shown uses single wires 42. The inner coil body 40 is, for example, composed of six single wires 42a, 42b, 42c, 42d, 42e, and 42f. The inner coil body 40 may be made of metallic materials, more specifically, of stainless steel (SUS302, SUS304, SUS316, etc.), piano wire, Ni-Ti alloys, or other highly elastic alloys, or of radiation-impermeable materials such as platinum, gold, tungsten, or their alloys.

[0057] like Figure 1 As shown, in guidewire 100, the tip of guidewire 100 is bent at a predetermined angle. Specifically, the mandrel 10 and the coil body 20, which is used as a cylindrical body, are bent (folded or bent) at the second cylindrical portion L2, described later. In detail, the narrow diameter portion 11 of the mandrel 10, the coil body 20, and the inner coil body 40 are bent at a predetermined angle. As a result, the vascular selectivity of guidewire 100 (the ability to select a specific vessel from multiple branched vessels and allow the tip of guidewire 100 to enter) can be improved.

[0058] A-2. Detailed structure of coil body 20:

[0059] Figure 2This is an explanatory diagram showing the external structure of the front end of the guidewire 100. Figure 2 (A) shows the YZ side structure obtained by viewing the front end of the guidewire 100 from the X-axis direction. Figure 2 (B) shows the XZ side structure obtained by viewing the front end of the guidewire 100 from the Y-axis direction. Figure 3 This is an explanatory diagram showing the cross-sectional structure of the front end of the guidewire 100. Figure 3 (A) shows Figure 2 The cross-sectional structure of the mandrel 10 (the first cylindrical portion L1 of the coil body 20, described later) at position IIIA-IIIA. Figure 3 (B) shows Figure 2 The cross-sectional structure of the mandrel 10 (the second cylindrical part L2 of the coil body 20, described later) at position IIIB-IIIB.

[0060] like Figure 1 and Figure 2 As shown, the coil body 20 has a first cylindrical portion L1, a second cylindrical portion L2, and a third cylindrical portion L3. The first cylindrical portion L1 includes the front end of the coil body 20 and is a portion extending linearly along the axial direction of the guide wire 100 (the front end of the narrow diameter portion 11 of the mandrel 10). The first cylindrical portion L1 surrounds the narrow diameter portion 11 and the linear front end of the inner coil body 40. The third cylindrical portion L3 includes the base end of the coil body 20 and is a portion extending linearly along the axial direction of the guide wire 100 (the base end of the narrow diameter portion 11 of the mandrel 10). The third cylindrical portion L3 surrounds the narrow diameter portion 11, a portion of the tapered portion 12, and the linear base end of the inner coil body 40. The second cylindrical portion L2 is the portion that connects and deforms the first cylindrical portion L1 and the third cylindrical portion L3. The second cylindrical portion L2 surrounds the narrow diameter portion 11 and the bent portion of the inner coil body 40.

[0061] like Figure 3 As shown in (A), the cross-sectional shape of the first cylindrical portion L1 of the coil body 20 is circular. Specifically, in the cross-section of the first cylindrical portion L1, the center or centroid of each strand 22 (each of strands 22a, 22b, 22c, 22d, 22e, 22f, 22g, and 22h) is arranged on circle M31. Furthermore, in the inner coil body 40, the cross-sectional shape of the first inner cylindrical portion L4 located within the first cylindrical portion L1 is circular. Specifically, in the cross-section of the first inner cylindrical portion L4, the center or centroid of each single wire 42 (each of 42a, 42b, 42c, 42d, 42e, and 42f) is arranged on circle N31.

[0062] like Figure 3As shown in (B), the cross-sectional shape of the second cylindrical portion L2 of the coil body 20 is non-circular, for example, oblong. Specifically, on the cross-section of the second cylindrical portion L2, the center or centroid of each strand 22 (each of strands 22a, 22b, 22c, 22d, 22e, 22f, 22g, 22h) is arranged on an oblong circle M32. It should be noted that in this specification, "oblong" includes elliptical. Furthermore, in the inner coil body 40, the cross-sectional shape of the second inner cylindrical portion L5 located within the second cylindrical portion L2 is circular. Specifically, on the cross-section of the second inner cylindrical portion L5, the center or centroid of each single wire 42 (42a, 42b, 42c, 42d, 42e, 42f) is arranged on a circle N32.

[0063] like Figure 3 As shown, the maximum dimension D4 of the cross-section of the second cylindrical portion L2 of the coil body 20 (hereinafter referred to as "the maximum dimension D4 of the second cylindrical portion L2") is greater than the maximum dimension D1 (diameter, hereinafter referred to as "the maximum dimension D1 of the first cylindrical portion L1") of the cross-section of the first cylindrical portion L1. For example... Figure 2 As shown in (B), when viewed from the short axis direction (Y-axis direction) of the cross-sectional shape of the second cylindrical portion L2, the width dimension of the coil body 20 changes slowly in a manner that it continuously narrows from the second cylindrical portion L2 to the first cylindrical portion L1.

[0064] like Figure 3 As shown, the minimum dimension D3 of the cross-sectional shape of the second cylindrical portion L2 of the coil body 20 (hereinafter referred to as "the minimum dimension D3 of the second cylindrical portion L2") is smaller than the minimum dimension D1 (diameter, hereinafter referred to as "the minimum dimension D1 of the first cylindrical portion L1") of the cross-sectional shape of the first cylindrical portion L1. For example... Figure 2 As shown in (A), when viewed from the long axis direction (X-axis direction) of the cross-sectional shape of the second cylindrical portion L2, the width of the coil body 20 gradually changes in a manner that continuously widens from the second cylindrical portion L2 to the first cylindrical portion L1. With this structure, the variation in insertion resistance of the guidewire 100 within the blood vessel, as described later, can be mitigated.

[0065] like Figure 2 As shown, the cross-sectional shape of the third cylindrical portion L3 of the coil body 20 is the same as that of the first cylindrical portion L1, and their dimensions are also the same (D2 = D1). The maximum dimension D2 of the cross-sectional shape of the third cylindrical portion L3 of the coil body 20 is smaller than the maximum dimension D4 (diameter) of the second cylindrical portion L2. Figure 2 As shown in (B), when viewed from the short axis direction (Y-axis direction) of the cross-sectional shape of the second cylindrical portion L2, the width dimension of the coil body 20 changes slowly in a manner that it continuously narrows from the second cylindrical portion L2 to the third cylindrical portion L3.

[0066] like Figure 2 As shown, the minimum dimension D2 (diameter) of the cross-section of the third cylindrical portion L3 is greater than the minimum dimension D3 of the second cylindrical portion L2. Figure 2 As shown in (A), when viewed from the long axis direction (X-axis direction) of the cross-section of the second cylindrical portion L2, the width dimension of the coil body 20 changes slowly in a manner that it continuously widens from the second cylindrical portion L2 to the third cylindrical portion L3.

[0067] The ratio (D4 / D1) of the maximum dimension D4 of the second cylindrical portion L2 of the coil body 20 to the maximum dimension D1 of the first cylindrical portion L1 of the coil body 20 is preferably 1.02 or more, and preferably 1.19 or less. Furthermore, the ratio (D3 / D1) of the minimum dimension D3 of the second cylindrical portion L2 of the coil body 20 to the minimum dimension D1 of the first cylindrical portion L1 of the coil body 20 is preferably 0.81 or more, and preferably 0.98 or less. Additionally, the ratio (D4 / D3) of the maximum dimension D4 of the second cylindrical portion L2 of the coil body 20 to the minimum dimension D3 of the second cylindrical portion L2 is preferably 1.03 or more, and preferably 1.45 or less.

[0068] like Figure 3 As shown in (A), the first cylindrical portion L1 of the coil body 20 is separated from the inner coil body 40 over its entire circumference. On the other hand, as... Figure 3 As shown in (B), the distance between the second cylindrical portion L2 and the inner coil body 40 in the long axis direction is longer than the distance between the second cylindrical portion L2 and the inner coil body 40 in the short axis direction.

[0069] A-3. Method for manufacturing guidewire 100:

[0070] The guide wire 100 of this embodiment can be manufactured, for example, by the following method. First, a mandrel 10, which is shaped by mechanical grinding or the like, is prepared; a coil body 20 (with a circular cross-section) is made by winding multiple (e.g., 8) strands (wires) into a spiral shape; and an inner coil body 40 (with a circular cross-section) is made by winding 6 single wires (wires) into a spiral shape. The inner coil body 40 is fixed around the narrow diameter portion 11 of the mandrel 10. At this time, the mandrel 10 and the inner coil body 40 are straight along their entire length and do not have any bends.

[0071] Next, the mandrel 10, to which the inner coil body 40 is fixed, is inserted into the hollow portion of the coil body 20, forming a front end-side joint 30 and a base end-side joint 32 that join the coil body 20 to the mandrel 10. Then, a force is applied to a predetermined portion of the coil body 20, which becomes the second cylindrical portion L2, in a direction orthogonal to the axial direction of the coil body 20, causing plastic deformation of the coil body 20 to make its cross-sectional shape oblong, while simultaneously performing a bending process. Thus, a coil body 20 having the second cylindrical portion L2 is formed. For example, using the above method, a guide wire 100 with the above structure can be manufactured.

[0072] A-4. Effects of this implementation method:

[0073] In this embodiment, during the process of the guidewire 100 entering, for example, a lesion or the vessel wall (hereinafter referred to as "lesion, etc.") in a blood vessel, the first cylindrical portion L1 of the coil body 20 in the guidewire 100 enters the lesion, etc., and then the second cylindrical portion L2 of the coil body 20 begins to enter the lesion, etc. Here, in this embodiment, the maximum size D4 of the second cylindrical portion L2 is greater than the maximum size D1 of the first cylindrical portion L1 (see reference). Figure 2 (B) Therefore, when the second cylindrical portion L2 begins to enter the lesion, the insertion resistance of the guidewire 100 relative to the blood vessel increases according to the difference in the maximum dimensions between the first cylindrical portion L1 and the second cylindrical portion L2 (=D4-D1). Specifically, the surgeon using the guidewire 100 can intuitively determine the location of the second cylindrical portion L2 of the guidewire 100 within the blood vessel by feeling the change in insertion resistance in the hand holding the base of the guidewire 100. For example, the surgeon can carefully insert the guidewire 100 by relying on the guidewire configuration and the change in insertion resistance of the guidewire 100 under intraoperative X-ray fluoroscopy images, thus, for example, preventing damage to the blood vessel.

[0074] In this embodiment, the minimum dimension D3 of the second cylindrical portion L2 is smaller than the minimum dimension D1 of the first cylindrical portion L1 (see reference). Figure 2 (A) Therefore, according to this embodiment, compared to a structure where the minimum dimension D3 of the second cylindrical portion L2 is greater than or equal to the minimum dimension D1 of the first cylindrical portion L1, the smaller cross-sectional area of ​​the second cylindrical portion L2 correspondingly suppresses the reduction in the penetration performance of the guidewire 100. Thus, through this embodiment, damage to blood vessels can be suppressed, and the reduction in the penetration performance of the guidewire 100 can be suppressed.

[0075] In this embodiment, the maximum dimension D2 of the cross-sectional shape of the third cylindrical portion L3 of the coil body 20 is smaller than the maximum dimension D4 of the second cylindrical portion L2 (see reference). Figure 2(B) Therefore, according to this embodiment, for example, compared to a structure where the maximum dimension D2 of the cross-section of the third cylindrical portion L3 is greater than or equal to the maximum dimension D4 of the second cylindrical portion L2, it is possible to suppress excessive insertion resistance as a whole of the guidewire 100.

[0076] In this embodiment, the cross-sectional shape of the first cylindrical portion L1 is circular (preferably perfectly circular), and the cross-sectional shape of the second cylindrical portion L2 is oblong. Therefore, with this embodiment, for example, compared to a structure where the cross-sectional shape of the first cylindrical portion L1 is also oblong, the tip of the guide wire 100 can be rotated smoothly.

[0077] In this embodiment, among the strands (an example of the wire material of the coil body 20) 22a, 22b, 22c, 22d, 22e, 22f, 22g, and 22h included in the coil body 20, adjacent portions along the length direction of the coil body 20 are in contact with each other. Therefore, according to this embodiment, the second cylindrical portion L2 can be easily manufactured by applying mechanical force to the coil body 20.

[0078] B. Second implementation method:

[0079] B-1. Structure of guidewire 100a:

[0080] Figure 4 This is an explanatory diagram that schematically shows the structure of the guide wire 100a in the second embodiment. Figure 4 The overall structure of the guide wire 100a when viewed in the positive X-axis direction is shown, and the longitudinal section structure of the coil body 20a and the front end side joint 30, which will be described later, is shown.

[0081] The structure of the guide wire 100a in the second embodiment differs from that of the guide wire 100 in the first embodiment in that the structure of the coil body 20a is different. Furthermore, the guide wire 100a in the second embodiment differs from the guide wire 100 in that it lacks an inner cylindrical body (inner coil body 40) and a bending portion. Hereinafter, descriptions of structures in the guide wire 100a of the second embodiment that are identical to those in the guide wire 100 of the first embodiment will be omitted by using the same reference numerals.

[0082] like Figure 4As shown, the guide wire 100a includes a mandrel 10, a coil body 20a, a front end joint 30, and a base end joint 32. The coil body 20a is formed into a hollow cylindrical shape, for example, by tightly winding 10 wires 22a (single wires). The coil body 20a is arranged around the mandrel 10a in a manner that covers the mandrel 10. Here, the guide wire 100a is the guide wire before forming, and neither the mandrel 10a nor the coil body 20a has a bend. In addition, there is no inner cylindrical body between the mandrel 10 and the coil body 20a.

[0083] Figure 5 An explanatory diagram showing the cross-sectional structure of the front end of guidewire 100a. Figure 5 (A) shows Figure 4 The cross-sectional structure of the mandrel 10a (the first cylindrical portion L1a of the coil body 20a, described later) at position VA-VA. Figure 5 (B) shows Figure 4 The cross-sectional structure of the mandrel 10a (the second cylindrical part L2a of the coil body 20a, described later) at the VB-VB position.

[0084] like Figure 4 As shown, the coil body 20a has a first cylindrical portion L1a, a second cylindrical portion L2a, and a third cylindrical portion L3a. The first cylindrical portion L1a includes the front end of the coil body 20a and extends linearly along the axial direction of the guide wire 100a (the front end of the thin-diameter portion 11 of the mandrel 10). The third cylindrical portion L3a includes the base end of the coil body 20a and extends linearly along the axial direction of the guide wire 100a (the base end of the thin-diameter portion 11 of the mandrel 10). The second cylindrical portion L2a connects the first cylindrical portion L1a and the third cylindrical portion L3a and extends linearly along the axial direction of the guide wire 100a (the thin-diameter portion 11 of the mandrel 10).

[0085] like Figure 5 As shown in (A), the cross-sectional shape of the first cylindrical portion L1a of the coil body 20a is circular (preferably perfectly circular). Specifically, in the cross-section of the first cylindrical portion L1a, the center or centroid of each wire (single wire) 22a is arranged on circle M51. Figure 5 As shown in (B), in the cross-section of the second cylindrical part L2a, the center or centroid of each wire (single wire) 22a is arranged on the elongated circle (ellipse) M52.

[0086] The maximum dimension D4a of the cross-section of the second cylindrical portion L2a of the coil body 20a is greater than the maximum dimension D1a of the cross-section of the first cylindrical portion L1a. In addition, the minimum dimension D3a of the cross-section of the second cylindrical portion L2a of the coil body 20a is smaller than the minimum dimension D1a (diameter) of the cross-section of the first cylindrical portion L1a.

[0087] Thus, even with the guidewire 100a of this embodiment, which does not have a bending portion, damage to blood vessels can be suppressed, and the reduction in the penetration performance of the guidewire 100a can be prevented. The surgeon can use the guidewire 100a in the state where the second cylindrical portion L2a is set to a bent or folded shape (in the shaped state) by manually bending the second cylindrical portion L2a.

[0088] C. Variations:

[0089] The technology disclosed in this specification is not limited to the above-described embodiments, and can be modified in various ways without departing from its spirit, for example, the following modifications are also possible.

[0090] The structures of guidewires 100 and 100a in the above embodiments are merely examples and can be modified in various ways. In the above embodiments, a coating may also be formed on the outermost periphery (outer periphery of the coil body 20) of the guidewires 100 and 100a. It should be noted that, as the material for forming the coating, hydrophobic coating materials such as silicone oil or fluororesin may be used, or hydrophilic coating materials such as polyvinylpyrrolidone, polyacrylic acid, polyacrylamide, polyvinyl alcohol, maleic anhydride copolymer, and hyaluronic acid may be used. It should be noted that, in order to improve the penetration of guidewires 100 and 100a into the lesion, the coating is preferably hydrophilic.

[0091] In the above embodiments, the coil bodies 20 and 20a cover the narrow diameter portion 11 and the tapered portion 12 of the mandrel 10, but the portion of the mandrel 10 covered by the coil bodies 20 and 20a can be arbitrarily changed. For example, the coil bodies 20 and 20a may only cover the narrow diameter portion 11 of the mandrel 10, or the coil bodies 20 and 20a may cover part or all of the wide diameter portion 13 in addition to the narrow diameter portion 11 and the tapered portion 12 of the mandrel 10. In addition, in the above embodiments, the coil bodies 20 and 20a are exemplified as cylindrical bodies, but the cylindrical body may also be a flexible tube (so-called slit tube) formed by forming a slit, or a flexible tube formed by an elastic material, etc.

[0092] In the first embodiment described above, the coil body 20 is configured such that multiple strands 22, formed by twisting multiple wires 24 and 26 together, are wound into a spiral shape, thereby forming a hollow cylindrical shape. However, the coil body 20 can also be configured such that one or more wires (single wires or stranded wires) are tightly or loosely wound into a spiral shape. In addition, the stranded wires 22 may also be composed only of side wires 26 and exclude the core wire 24.

[0093] In the first embodiment described above, the guidewire 100 may be configured without the aforementioned bending portion at the time of manufacture, and the coil body 20 may have a first cylindrical portion L1 and a second cylindrical portion L2. In this case, before a surgeon inserts the guidewire 100 into a blood vessel, a shape-adding process called "forming" is performed, in which the leading end of the guidewire 100 (the second cylindrical portion L2) is bent to a predetermined angle beforehand, so that the cross-sectional shape of the first cylindrical portion and the cross-sectional shape of the second cylindrical portion satisfy the aforementioned predetermined dimensional relationship (the maximum dimension of the cross-sectional shape of the second cylindrical portion is greater than the maximum dimension of the cross-sectional shape of the first cylindrical portion, and the minimum dimension of the cross-sectional shape of the second cylindrical portion is less than the minimum dimension of the cross-sectional shape of the first cylindrical portion). Furthermore, in the above embodiment, the inner coil body 40 may also be omitted.

[0094] In the first embodiment described above, the cross-sectional shape of the first cylindrical portion L1 of the coil body 20 is not limited to a circle; it can be an oblong or polygonal shape, as long as the specified dimensional relationship is satisfied. Furthermore, the cross-sectional shape of the second cylindrical portion L2 of the coil body 20 can be non-circular as long as the specified dimensional relationship is satisfied; for example, it can be an oblong shape, but it is not limited to this, and it can also be rectangular. In short, if the maximum dimension D4 of the second cylindrical portion L2 of the coil body 20 is greater than the maximum dimension D1 of the first cylindrical portion L1, and the minimum dimension D3 of the second cylindrical portion L2 of the coil body 20 is less than the minimum dimension D1 of the first cylindrical portion L1 (the specified dimensional relationship) is satisfied, then the effect of the present invention is achieved. Additionally, in the above embodiment, the width of the coil body 20 can also be configured such that, when viewed from the long axis direction (X-axis direction) of the cross-sectional shape of the second cylindrical portion L2, the width varies in stages from the second cylindrical portion L2 to the first cylindrical portion L1. Alternatively, the width of the coil body 20 can be configured such that, when viewed from the short axis direction (Y-axis direction) of the cross-section of the second cylindrical portion L2, the width of the coil body 20 changes in a stepwise narrowing manner from the second cylindrical portion L2 to the first cylindrical portion L1.

[0095] In the first embodiment described above, the minimum dimension D2 of the cross-sectional shape of the third cylindrical portion L3 can be less than or equal to the minimum dimension D3 of the second cylindrical portion L2. Furthermore, in the first embodiment described above, the maximum dimension D2 of the cross-sectional shape of the third cylindrical portion L3 of the coil body 20 can be greater than or equal to the maximum dimension D4 of the second cylindrical portion L2. It should be noted that, for example, as in the first embodiment described above… Figure 2As shown, if the maximum dimension D2 of the cross-section of the third cylindrical portion L3 is closer to the maximum dimension D1 of the first cylindrical portion L1 than the maximum dimension D4 of the second cylindrical portion L2, and the minimum dimension D2 of the cross-section of the third cylindrical portion L3 is closer to the minimum dimension D1 of the first cylindrical portion L1 than the minimum dimension D3 of the second cylindrical portion L2, then the insertion resistance of the portion other than the second cylindrical portion L2 is approximately uniform, thereby improving the insertion and operability of the guidewire 100 as a whole.

[0096] Figure 6 This is an explanatory diagram showing the cross-sectional structure of the tip of the guidewire in a modified example 1 of the first embodiment. (As shown...) Figure 6 As shown, Modification 1 differs from the first embodiment in that the second cylindrical portion L2 of the coil body 20 and the second inner cylindrical portion L5 of the inner coil body 40 are in contact with each other, but are otherwise the same as the first embodiment. In Modification 1, the minimum inner diameter of the second cylindrical portion L2 of the coil body 20 is equal to the outer diameter of the second inner cylindrical portion L5 of the inner coil body 40. Specifically, in the short axis direction of the cross-section of the second cylindrical portion L2, the second cylindrical portion L2 (the pair of stranded wires 22 (side wires 26) on both sides) are in contact with the second inner cylindrical portion L5 in a manner that they are clamped together. According to this Modification 1, when the mandrel 10 is rotated, the second cylindrical portion L2 and the second inner cylindrical portion L5 become one and are easy to rotate due to the frictional resistance generated between them. Therefore, in addition to the effect of the guide wire 100 in the first embodiment described above, the torque transmission of the guide wire 100 (especially the torque transmission in the initial stage of rotation) can also be improved.

[0097] Figure 7 This is an explanatory diagram showing the cross-sectional structure of the tip of the guide wire in a modified example 2 of the first embodiment. (As shown) Figure 7 As shown, Modification 2 differs from Modification 1 in that the second inner cylindrical portion L5 contacts the mandrel 10x (narrow diameter portion 11), but is otherwise the same as Modification 1. In Modification 2, the minimum inner diameter of the second inner cylindrical portion L5 of the coil body 40 is equal to the diameter (maximum diameter) of the mandrel 10x. Specifically, the second inner cylindrical portion L5 (single wire 42) contacts the outer peripheral surface of the mandrel 10x in a manner that surrounds the mandrel 10x. According to this Modification 2, when the mandrel 10x is rotated, the second cylindrical portion L2 and the mandrel 10x become one due to the frictional resistance generated between them, thus facilitating rotation. Therefore, in addition to the effect of the guide wire 100 described in Modification 1, the torque transmission performance of the guide wire 100 (especially the torque transmission performance in the initial stage of rotation) can be effectively improved.

[0098] Figure 8 This is an explanatory diagram showing the cross-sectional structure of the tip of the guidewire in a variation of the first embodiment, Example 3. Figure 8 As shown, in variation 3, the second inner cylindrical portion L5 of the inner coil body 40 has an elongated oval shape. Specifically, in the cross-section of the second inner cylindrical portion L5, the center or centroid of each individual wire 42 is positioned on an elongated oval (ellipse) N82. The maximum dimension D5 of the cross-section of the second inner cylindrical portion L5 is greater than the minimum dimension D6. The maximum dimension D5 of the cross-section of the second inner cylindrical portion L5 is greater than that of the first inner cylindrical portion L4 (see reference). Figure 3 The maximum dimension of the cross-section of (A) is smaller than the minimum dimension D6 of the cross-section of the second inner cylindrical portion L5 (see reference). Figure 3 The minimum dimension of the cross-sectional shape of (A)). According to this modified example 3, the portion with an oblong cross-section obtained by applying mechanical force to the cylindrical member is the second inner cylindrical portion L5, and the portion with a circular cross-section that is not subjected to the mechanical force is the first inner cylindrical portion L4. Thus, a guide wire that satisfies the above-mentioned "prescribed dimensional relationship of the inner cylindrical body" can be easily obtained. In addition, when the mandrel 10 is rotated, the second cylindrical portion L2 and the second inner cylindrical portion L5, which are not circular, engage with each other, become one piece, and are easy to rotate. Therefore, in addition to the effect of the guide wire 100 in the first embodiment, the torque transmission performance of the guide wire 100 can be further improved. It should be noted that if the maximum dimension D5 of the second inner cylindrical portion L5 is greater than the minimum value of the inner diameter of the second cylindrical portion L2, the second cylindrical portion L2 and the second inner cylindrical portion L5 are more likely to engage with each other, thus further improving the torque transmission performance of the guide wire 100.

[0099] Figure 9 This is an explanatory diagram showing the cross-sectional structure of the tip of the guide wire in Variation 4 of the first embodiment. (See diagram below.) Figure 9 As shown, in Modification 4, the second cylindrical portion L2 of the coil body 20 differs from Modification 3 in that the second cylindrical portion L2 of the coil body 20 and the second inner cylindrical portion L5 of the inner coil body 40 are in contact with each other, but are otherwise the same as Modification 3. In Modification 4, the minimum inner diameter of the second cylindrical portion L2 of the coil body 20 is equal to the minimum outer diameter of the second inner cylindrical portion L5 of the inner coil body 40. Specifically, in the short axis direction of the second cylindrical portion L2, the second cylindrical portion L2 (the pair of stranded wires 22 (side wires 26) on both sides) are in contact with the second inner cylindrical portion L5 by clamping it. According to this Modification 4, when the mandrel 10 is rotated, the second cylindrical portion L2 and the second inner cylindrical portion L5 become one and are easy to rotate due to the frictional resistance generated between them. Therefore, in addition to the effect of the guide wire 100 in Modification 3, the torque transmission performance of the guide wire 100 (especially the torque transmission performance in the initial stage of rotation) can be further improved.

[0100] Figure 10 This is an explanatory diagram showing the cross-sectional structure of the tip of the guide wire in Variation 5 of the first embodiment. (As shown) Figure 10 As shown, Modification 5 differs from Modification 4 in that the second inner cylindrical portion L5 contacts the mandrel 10x (narrow diameter portion 11), but is otherwise the same as Modification 4. In Modification 5, the minimum inner diameter of the second inner cylindrical portion L5 of the coil body 40 is equal to the diameter (maximum diameter) of the mandrel 10x. Specifically, the second inner cylindrical portion L5 (single wire 42) contacts the outer peripheral surface of the mandrel 10x in a manner that surrounds the mandrel 10x. According to this Modification 5, when the mandrel 10x is rotated, the second cylindrical portion L2 and the mandrel 10x become one due to the frictional resistance generated between them and are easy to rotate. Therefore, in addition to the effect of the guide wire 100 in Modification 4, the torque transmission performance of the guide wire 100 (especially the torque transmission performance in the initial stage of rotation) can be effectively improved.

[0101] The materials used for the components in the above embodiments are merely examples and can be varied. Furthermore, the methods for manufacturing the guide wires in the above embodiments are also merely examples and can be varied. For instance, a portion of a mandrel (core) with a circular cross-section can be extruded, and wire or stranded wire can be wound around the partially extruded mandrel to form a coil.

[0102] In the above embodiments, a guidewire for guiding a catheter to a target location within a blood vessel has been described as an example. However, the technology disclosed in this specification can also be applied to guidewires for guiding medical devices to target locations within body cavities (blood vessels, digestive tract, ureters, etc.).

[0103] Explanation of reference numerals in the attached figures

[0104] 10, 10a, 10x: Mandrel; 11: Narrow diameter section; 12: Tapered section; 13: Wide diameter section; 20, 20a: Coil body; 22, 22a, 22b, 22c, 22d, 22e, 22f, 22g, 22h: Stranded wire; 42, 42a, 42b, 42c, 42d, 42e, 42f: Single wire; 24: Core wire; 26: Side wire; 30: Front end side joint; 32: Base end side joint; 40: Inner coil body; 100, 100a: Guide wire; L1, L1a: First cylindrical section; L2, L2a: Second cylindrical section; L3, L3a: Third cylindrical section; L4: First inner cylindrical section; L5: Second inner cylindrical section.

Claims

1. A guidewire, wherein, The guidewire has the following features: mandrel; and A cylindrical body, the cylindrical body being configured to surround the outer periphery of the front end side portion of the mandrel. The cylindrical body has: a first cylindrical portion and a second cylindrical portion, wherein the second cylindrical portion is located closer to the base end of the cylindrical body than the first cylindrical portion. The maximum dimension of the cross-section of the second cylindrical portion is greater than the maximum dimension of the cross-section of the first cylindrical portion, and the minimum dimension of the cross-section of the second cylindrical portion is less than the minimum dimension of the cross-section of the first cylindrical portion.

2. The guidewire according to claim 1, wherein, The cylindrical body has a third cylindrical portion, which is located closer to the base end of the cylindrical body than the second cylindrical portion. The maximum dimension of the cross-section of the third cylindrical portion is smaller than the maximum dimension of the cross-section of the second cylindrical portion.

3. The guidewire according to claim 2, wherein, The maximum dimension of the cross-section of the third cylindrical portion is closer to the maximum dimension of the cross-section of the first cylindrical portion than the maximum dimension of the cross-section of the second cylindrical portion, and the minimum dimension of the cross-section of the third cylindrical portion is closer to the minimum dimension of the cross-section of the first cylindrical portion than the minimum dimension of the cross-section of the second cylindrical portion.

4. The guidewire according to any one of claims 1 to 3, wherein, The first cylindrical portion has a circular cross-section, and the second cylindrical portion has an oblong cross-section.

5. The guidewire according to any one of claims 1 to 4, wherein, The mandrel and the cylindrical body are bent at the second cylindrical portion.

6. The guidewire according to any one of claims 1 to 5, wherein, The cylindrical body is a coil body, which has a structure in which one or more wires are wound into a spiral shape.

7. The guidewire according to claim 6, wherein, The wire is a single wire or a stranded wire.

8. The guidewire according to claim 6 or 7, wherein, In the wire, adjacent portions along the length of the coil body are in contact with each other.

9. The guidewire according to any one of claims 1 to 8, wherein, The cylindrical body is a tube with slits.

10. The guidewire according to any one of claims 1 to 9, wherein, The guidewire has an inner cylindrical body that is housed within at least the second cylindrical portion of the cylindrical body and is configured to surround at least a portion of the front end side portion of the mandrel.

11. The guidewire according to claim 10, wherein, The inner cylindrical body has: a first inner cylindrical portion and a second inner cylindrical portion, wherein the second inner cylindrical portion is located closer to the base end of the inner cylindrical body than the first inner cylindrical portion. The maximum dimension of the cross-section of the second inner cylindrical portion is greater than the maximum dimension of the cross-section of the first inner cylindrical portion, and the minimum dimension of the cross-section of the second inner cylindrical portion is less than the minimum dimension of the cross-section of the first cylindrical portion.

12. The guidewire according to claim 11, wherein, The cross-section of the first inner cylindrical portion is circular, and the cross-section of the second inner cylindrical portion is oblong.

13. The guidewire according to any one of claims 10 to 12, wherein, The inner cylindrical body has: a first inner cylindrical portion and a second inner cylindrical portion, wherein the second inner cylindrical portion is located closer to the base end of the inner cylindrical body than the first inner cylindrical portion. The second cylindrical portion of the cylindrical body is in contact with the second inner cylindrical portion of the inner cylindrical body.

14. The guidewire according to any one of claims 10 to 13, wherein, The inner cylindrical body has: a first inner cylindrical portion and a second inner cylindrical portion, wherein the second inner cylindrical portion is located closer to the base end of the inner cylindrical body than the first inner cylindrical portion. The second inner cylindrical portion of the inner cylindrical body is in contact with the mandrel.

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