Guide wire

Abstract

To improve the efficiency and safety of a procedure by suppressing an unintended movement of a guide wire inside a vessel.SOLUTION: A guide wire 100 includes a long-sized wire body 110 and a lubricant coating layer 120 covering at least part of the wire body 110. The lubricant coating layer 120 is formed of a material that is swellable in a wet condition, and includes at least one bulge part 121 having a tip bulge part 122 formed by a change in the thickness of the lubricant coating layer 120. The tip bulge part 122 includes a first region R1, a second region R2 provided on a base end side of the first region R1, and a tip bulge part maximum outer diameter part M1 provided between the first region R1 and the second region R2. A length X1 along the major axis direction of the first region R1 is longer than a length X2 along the major axis direction of the second region R2.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a guidewire. [Background technology]

[0002] A guidewire is a medical device used to guide various catheters that treat lesions occurring in blood vessels to the lesion. A guidewire has a core wire (core member), an outer coil (tubular member) arranged to cover the outer periphery of the tip of the core wire, and a hydrophilic resin coating (lubricating coating layer) formed to cover the outer periphery of the outer coil (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-221249 A Summary of the Invention [Problem to be solved by the invention]

[0004] The guidewire of Patent Document 1 needs to be maintained in a state of passing through the lesion in order to guide a device such as a catheter to the lesion. However, when the device is operated, the guidewire may unintentionally move toward the distal end or proximal end of the lesion. If the guidewire unintentionally moves away from the lesion, it is necessary to reposition the guidewire at the lesion, which reduces the efficiency of the procedure. In addition, the unintentional movement of the guidewire may cause it to get lost in a side branch of a blood vessel, resulting in vascular perforation, which may reduce the safety of the procedure.

[0005] At least one embodiment of the present invention has been made in consideration of the above-mentioned circumstances, and aims to provide a guidewire that can improve the efficiency and safety of procedures by suppressing unintended movement within blood vessels. [Means for solving the problem]

[0006] The above object of the present invention can be achieved by any one of the following (1) to (5).

[0007] (1) A guidewire having a long wire body and a lubricous coating layer covering at least a portion of the wire body, wherein the lubricous coating layer is formed of a material that swells when wet, and has at least one bulge having a distal bulge formed by a change in thickness of the lubricous coating layer, the distal bulge including a first region, a second region located on the base end side of the first region, and a distal bulge maximum outer diameter portion located between the first region and the second region, and the length of the first region along the longitudinal direction is longer than the length of the second region along the longitudinal direction.

[0008] (2) The guide wire described in (1) above, wherein the bulge portion includes a base end bulge portion that is located base end side of the tip bulge portion, and the base end bulge portion includes a third region, a fourth region that is located base end side of the third region, and a base end bulge portion maximum outer diameter portion that is located between the third region and the fourth region, and the length along the longitudinal direction of the third region is shorter than the length along the longitudinal direction of the fourth region.

[0009] (3) The guide wire according to (1) or (2) above, wherein the wire body includes a core member and a marker portion arranged at the tip of the core member and having radiopacity, and the tip bulge portion is provided at the base end of the marker portion.

[0010] (4) The guide wire described in (3) above, wherein the marker portion is a coil formed by winding wire to cover the outer periphery of the core member, and the length along the longitudinal direction between the base end of the distal bulge portion and the tip of the proximal bulge portion is longer than the pitch of the coil.

[0011] (5) The guide wire described in (3) above, wherein the marker portion is a coil formed by winding wire to cover the outer periphery of the core member, and the length of the tip bulge portion along the longitudinal axis is longer than the pitch of the coil. Effect of the Invention

[0012] According to one embodiment of the present invention, the guidewire has a distal bulge formed of a lubricating coating layer at the distal end of the wire body. The distal bulge is formed by varying the thickness of the lubricating coating layer, and has an outer peripheral surface including a curved surface that is convex radially outward from the wire body. Therefore, the distal bulge can suppress unintended movement of the guidewire in a blood vessel after passing through a lesion. Therefore, the guidewire can improve the efficiency and safety of the procedure by suppressing unintended movement in a blood vessel. [Brief description of the drawings]

[0013] [Figure 1] 2 is a partially enlarged cross-sectional view of the vicinity of the distal end of the guide wire according to the present invention. FIG. [Diagram 2] FIG. 1 is a schematic cross-sectional view of a first embodiment of a guidewire according to the present invention. [Diagram 3] FIG. 2 is a schematic cross-sectional view of a second embodiment of the guidewire according to the present invention. [Figure 4A] FIG. 2 is a diagram for explaining the shape of a tip bulge in a bulging portion of a lubricant coating layer. [Figure 4B] FIG. 2 is a diagram for explaining the shape of a proximal bulge in a bulging portion of a lubricant coating layer. [Figure 5A] 13 is a partially enlarged cross-sectional view of the vicinity of the tip portion of the guidewire of Modified Example 1. FIG. [Figure 5B] 13 is a partially enlarged cross-sectional view of the vicinity of the tip portion of another embodiment of the guide wire of Modification Example 1. FIG. [Figure 5C] FIG. 11 is a cross-sectional view of a guidewire according to a first modified example. [Figure 6] FIG. 11 is a partially enlarged cross-sectional view of the vicinity of the tip portion of the guidewire of Modified Example 2. [Figure 7A] FIG. 13 is a partially enlarged cross-sectional view of the vicinity of the tip portion of the guidewire of Modification Example 3. [Figure 7B] 13 is a partially enlarged cross-sectional view of the vicinity of the tip portion of another configuration of the guidewire of Modification Example 3. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, the embodiments for carrying out the present invention will be described in detail with reference to the drawings. The embodiments shown here are merely illustrative in order to embody the technical idea of ​​the present invention, and do not limit the present invention. Furthermore, all other embodiments, examples, and operational techniques that can be conceived by those skilled in the art without departing from the gist of the present invention are included in the scope and gist of the present invention, and are included in the scope of the inventions described in the claims and their equivalents.

[0015] Furthermore, for the convenience of illustration and ease of understanding, the drawings attached to this specification may be represented diagrammatically with appropriate changes in scale, aspect ratio, shape, etc. from the actual product; however, these are merely examples and are not intended to limit the interpretation of the present invention.

[0016] For ease of explanation, the following directions are defined in this specification. In Fig. 1, the "longitudinal direction" is the direction along the central axis C of the guidewire 100. The "radial direction" is the direction moving away from or approaching the central axis C of the guidewire 100 in an orthogonal cross section (transverse cross section) with the central axis C of the guidewire 100 as the reference axis. The "circumferential direction" is the rotational direction with the central axis C of the guidewire 100 as the reference axis.

[0017] The side of the guidewire 100 that is inserted into a blood vessel is referred to as the “distal side,” and the side opposite the distal side (the side held by the surgeon) is referred to as the “base side.” A portion including a certain range from the distal end (the most distal end) along the longitudinal direction is referred to as the “distal portion,” and a portion including a certain range from the proximal end (the most proximal end) along the longitudinal direction is referred to as the “base portion.”

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

[0019] The guidewire 100 according to the present invention is a medical device that is inserted into a blood vessel to guide a catheter or a stent for intravascular treatment to a lesion. Note that the guidewire 100 can also be inserted into a body lumen other than a blood vessel (such as a blood vessel, a ureter, a bile duct, a fallopian tube, or a hepatic duct) depending on the purpose of treatment.

[0020] As shown in FIG. 1, the guidewire 100 has a long wire body 110 and a lubricant coating layer 120 that covers at least a portion of the wire body 110.

[0021] <Wire body> The wire body 110 constitutes the main body of the guidewire 100, and has a lubricous coating layer 120 formed on at least a portion of its outer circumferential surface. The wire body 110 includes a core member 10 and a marker portion 21 that is disposed at the distal end of the core member 10 and has radiopaque properties.

[0022] The wire body 110 can adopt any known form, such as a first coil-type configuration (guidewire 100A) in which a coil (tubular member 20A) is provided on a core member 10 as shown in Fig. 2, or a second jacket-type configuration (guidewire 100B) in which the entire core member 10 is covered with a resin layer 40B as shown in Fig. 3. The configurations of guidewires 100A and 100B will be described below as examples of the configuration of guidewire 100 of the present invention.

[0023] <First form> The configuration of the first mode of guidewire 100 will be described with reference to FIG.

[0024] 2, the guidewire 100A according to the first embodiment has a wire body 110A and a covering layer 40A covering at least a part of the wire body 110A. The wire body 110A includes a long core member 10A, a tubular member 20A covering the periphery of a distal end of the core member 10A, and a fixing portion 30A fixing the tubular member 20A to the core member 10A.

[0025] The core member 10A includes a first core portion 11A and a second core portion 12A disposed on the base end side of the first core portion 11A and joined to the first core portion 11A. The first core portion 11A is a long member extending from the tip of the second core portion 12A to the tip side of the guidewire 100A along the longitudinal direction. The second core portion 12A is a long member extending from the base end of the first core portion 11A to the base end side of the guidewire 100A. The first core portion 11A and the second core portion 12A can be joined by welding, brazing, or soldering. The first core portion 11A and the second core portion 12A may be connected using a cylindrical connecting member. The core member 10A may be formed of a single continuous member.

[0026] The core member 10A can be made of a known material applicable to a guidewire, such as a superelastic alloy such as a nickel-titanium alloy, stainless steel, etc. The first core portion 11A is preferably made of a material having a lower rigidity than the material of the second core portion 12A, but the first core portion 11A and the second core portion 12A may be made of the same material.

[0027] The tubular member 20A is a coil formed by winding a wire around the core member 10A in a spiral shape. The tubular member 20A is formed of a first coil 21A disposed at the tip of the first core portion 11A, and a second coil 22A disposed at the base end side of the first coil 21A and coaxially disposed with the first core portion 11A. The first core portion 11A and the second coil 22A surround the first core portion 11A of the core member 10A and are fixed to the first core portion 11A. It is preferable that the outer diameters of the first coil 21A and the second coil 22A are constant from the tip to the base end. The tubular member 20A may be formed of one coil, or may be formed of three or more coils. The first core portion 11A of the tubular member 20A corresponds to the marker portion 21 in the guidewire 100.

[0028] The outer diameter of the wire material forming the first coil 21A is larger than the outer diameter of the wire material forming the second coil 22A. The cross-sectional shape of the wire material forming the first coil 21A and the second coil 22A is preferably circular, but may be elliptical or polygonal. In addition, the wire material forming the first coil 21A and the second coil 22A may be a twisted wire made of two or more wire materials, rather than a single wire material.

[0029] The wire material forming the first coil 21A and the second coil 22A of the tubular member 20A can be made of a material such as a metal, such as stainless steel, a superelastic alloy, a cobalt-based alloy, gold, platinum, or tungsten, or an alloy containing these metals. In particular, the wire material forming the first coil 21A is preferably made of a radiopaque material such as platinum. This improves the visibility of the guidewire 100A under radioscopy.

[0030] The material of the wire forming the first coil 21A and the second coil 22A of the tubular member 20A, the outer diameter, the cross-sectional shape, the pitch of the first coil 21A and the second coil 22A, etc. can be appropriately selected depending on the purpose of the guidewire 100A.

[0031] The fixing part 30A is a member for fixing the tubular member 20A to the core member 10A. The fixing part 30A has a tip fixing part 31A that fixes the tip of the tubular member 20A to the core member 10A, an intermediate fixing part 32A that fixes the intermediate part of the tubular member 20A to the core member 10A, and a base end fixing part 33A that fixes the base end of the tubular member 20A to the core member 10A.

[0032] The intermediate fixing part 32A is provided at a position where the base end of the first coil 21A and the tip end of the second coil 22A are intertwined in the first core part 11A. The intermediate fixing part 32A fixes the base end of the first coil 21A and the tip end of the second coil 22A to the first core part 11A via a cylindrical member formed of metal, resin material, or the like. The cylindrical member is disposed between the inner peripheral surface of the tubular member 20A and the outer peripheral surface of the core member 10A, and reduces the gap between the inner peripheral surface of the tubular member 20A and the outer peripheral surface of the core member 10A, making it easier to fix the tubular member 20A and the core member 10A coaxially. The intermediate fixing part 32A is located at a position about 30 mm from the tip of the guidewire 100A.

[0033] The fixing material forming the fixing portion 30A is a brazing material or a solder. The brazing material may be gold brazing or silver brazing. The solder may be tin-silver alloy solder, tin-lead alloy solder, or the like. The fixing material may be an adhesive.

[0034] The coating layer 40A includes a lubricating coating layer 41A and a proximal coating layer 42A formed on the proximal side of the lubricating coating layer 41A. The coating layer 40A is formed so as to cover the wire body 110A, and reduces friction generated between the guidewire 100A and a blood vessel or a catheter, thereby improving the operability and safety of the guidewire 100A.

[0035] The lubricating coating layer 41A covers each portion (the tubular member 20A, the fixing portion 30A) provided on the first core portion 11A and a portion of the first core portion 11A. The base-side coating layer 42A covers a portion of the core portion 10A that is located closer to the base end than the tubular member 20A. The base-side coating layer 42A may also cover the second core portion 12A.

[0036] At least a part of the lubricating coating layer 41A is formed of a material that can swell when wet. Such a lubricating coating layer 41A can be formed of a hydrophilic polymer. Examples of the hydrophilic polymer forming the lubricating coating layer 41A include cellulose-based polymers, polyethylene oxide-based polymers, maleic anhydride-based polymers (e.g., maleic anhydride copolymers such as methyl vinyl ether-maleic anhydride copolymers), acrylamide-based polymers (e.g., polyacrylamide, glycidyl methacrylate-dimethylacrylamide block copolymers), water-soluble nylon, polyvinyl alcohol, polyvinylpyrrolidone, and derivatives thereof. In particular, the lubricating coating layer 41A is preferably formed of a material that swells when wet to become a hydrogel. Hydrogels have appropriate elasticity, and can therefore mitigate the impact when the guidewire 100A comes into contact with the blood vessel wall.

[0037] The base-end covering layer 42A can be made of a low-friction material, such as fluorine-based resin (PTFE, ETFE, etc.) or silicone resin.

[0038] Next, a guidewire 100B of a second embodiment will be described. In the following description of the second embodiment, differences from the first embodiment will be described, and components having the same functions as those of the first embodiment will be denoted by the same or related reference numerals and detailed description thereof will be omitted.

[0039] <Second form> Next, the configuration of a second embodiment of the guidewire 100 according to the present invention will be described with reference to FIG.

[0040] 3, the guidewire 100B has a core member 10B extending in the longitudinal direction, a resin layer 40B coating the core member 10B, and a lubricant coating layer 30B coating the outer circumferential surface of the resin layer 40B. The core member 10B and the resin layer 40B constitute a wire body 110B of the guidewire 100B.

[0041] The core member 10B includes a first core portion 11B having at least a part of a tapered shape in which the outer diameter increases from the tip to the base end, and a second core portion 12B arranged adjacent to the base end of the first core portion 11B and having a constant outer diameter along the longitudinal direction. The first core portion 11B and the second core portion 12B are formed of a single continuous member. The core member 10B may be formed by joining the first core portion 11B and the second core portion 12B by welding, brazing, or soldering.

[0042] The core member 10B can be made of a material applicable to the above-mentioned core member 10A.

[0043] The resin layer 40B is formed so as to cover the entire core member 10B. The tip of the resin layer 40B has a rounded shape.

[0044] The resin layer 40B is preferably formed from a highly flexible material, such as polyolefins such as polyethylene and polypropylene, polyvinyl chloride, polyesters (PET, PBT, etc.), polyamide, polyimide, polyurethane, polystyrene, polycarbonate, silicone resins, fluorine-based resins (PTFE, ETFE, PFA, etc.), composite materials of these, various rubber materials such as latex rubber and silicone rubber, or composite materials combining two or more of these.

[0045] There is no particular limitation on the thickness of the resin layer 40B. Furthermore, the resin layer 40B is not limited to a single-layer structure, and may have a multi-layer structure.

[0046] The lubricous coating layer 30B is formed so as to cover at least a portion of the resin layer 40B, and reduces friction between the guidewire 100B and a blood vessel or a catheter, thereby improving the operability and safety of the guidewire 100B. Furthermore, by coating the resin layer 40B with the lubricous coating layer 30B, peel resistance is improved compared to when the lubricous coating layer 30B is directly coated on the core member 10B.

[0047] The lubricant coating layer 30B can be formed from a material that can be used for the lubricant coating layer 41A described above.

[0048] In the guidewire 100B, a tubular member 20B is provided at the tip of the first core portion 11B. The tubular member 20B is provided by fixing a coil or a cylindrical body made of a radiopaque material near the tip of the first core portion 11B via a fixing material such as an adhesive or solder. Examples of radiopaque materials include precious metals such as gold, platinum, and tungsten, and alloys containing these metals (e.g., platinum-iridium alloy). By providing the tubular member 20B at the tip of the first core portion 11B, the visibility of the guidewire 100B under radioscopy is improved. The tubular member 20B corresponds to the marker portion 21 in the guidewire 100.

[0049] In order to suppress unintended migration from the affected area, the guidewire 100 according to the present invention has a characteristic shape for the lubricious coating layer 120. The lubricious coating layer 120 according to the present invention will be described below.

[0050] <Lubricant coating layer> The lubricous coating layer 120 includes a bulging portion 121, a first coating portion 124, a second coating portion 125, and a third coating portion 126. The lubricous coating layer 120 corresponds to the lubricous coating layer 41A of the guidewire 100A and the lubricous coating layer 30B of the guidewire 100B. At least a portion of the lubricous coating layer 120 is formed from a material that can swell when wet.

[0051] <bulge> As shown in FIG. 1, the bulging portion 121 includes a distal bulging portion 122 and a proximal bulging portion 123. The bulging portion 121 is a portion of the lubricant coating layer 120 that covers a predetermined region of the distal end of the wire body 110 on the proximal side of the distal end of the wire body 110. The bulging portion 121 is formed by changing the thickness of the lubricant coating layer 120, and has an outer circumferential surface that includes a curved surface that is convex radially outward of the wire body 110. The bulging portion 121 includes at least the distal bulging portion 122. In this specification, the thickness of the lubricant coating layer 120 is the thickness when the material forming the lubricant coating layer 120 is in a swollen state when wet.

[0052] <Tip bulge> The distal bulge 122 is a portion of the lubricant coating layer 120 that covers a predetermined area of ​​the distal end of the wire body 110 on the proximal side of the distal end of the wire body 110 .

[0053] As shown in FIG. 4A, the tip bulge 122 has a first region R1 in which the thickness of the tip bulge 122 increases from the tip to the base end of the wire body 110, a tip bulge maximum outer diameter portion M1 that is continuous with the base end of the first region R1 and in which the outer diameter of the tip bulge 122 is maximum, and a second region R2 that is continuous with the base end of the tip bulge maximum outer diameter portion M1 and in which the thickness of the tip bulge 122 decreases from the tip to the base end.

[0054] 4A is a diagram showing a two-axis orthogonal coordinate system in which an axis along the central axis C of the wire body 110 is the x-axis (longitudinal direction of the guidewire 100) and an axis perpendicular to the x-axis and tangent to the tip of the tip bulge 122 is the y-axis (radial direction of the guidewire 100), with the central axis C of the guidewire 100 placed in a natural state being superimposed on the x-axis and the tip of the first region R1 of the guidewire 100 coinciding with the origin. The tip bulge 122 has a three-dimensional shape obtained by rotating a curve L1 formed by the outer circumferential surface of the tip bulge 122 shown in the first quadrant of the orthogonal coordinate system shown in FIG. 4A, about the central axis C as the axis of rotation.

[0055] As shown in FIG. 4A, in the first quadrant of a Cartesian coordinate system, if the function y=f(x) represents the curve L1 formed by the outer surface of the tip bulge 122 when the guidewire 100 is viewed from the side, the function y=f(x) has a second derivative f''(x) in a certain range of x (x>0). In FIG. 4A, the first region R1 of the tip bulge 122 corresponds to the range of x satisfying f'(x)>0 on the tip side of the maximum point P1 (first derivative f'(x)=0) on the curve L1 where the function y=f(x) is maximum and largest. In FIG. 4A, the tip bulge maximum outer diameter portion M1 of the tip bulge 122 corresponds to the range of x satisfying f'(x)=0 (maximum point P1). The second region R2 of the distal end bulge 122 corresponds to a section of x satisfying f'(x)<0 on the proximal side of the maximum point P1 on the curve L1 in FIG. 4A.

[0056] The first region R1 of the tip swelling portion 122 has a first region tip portion R11 that is a predetermined range from the tip of the first region R1 to the tip side of the first region R1 and is convex radially inward, and a first region base end portion R12 that is a base end side of the first region tip portion R11 and is convex radially outward. The first region R1 of the tip swelling portion 122 has a first inflection point P2 on the curve L1 in FIG. 4A where f″(x)=0 and the sign of f″(x) is inverted and the concavity and convexity of the curve L1 changes. The first region tip portion R11 corresponds to the section where f′(x)>0 and f″(x)>0 where the function y=f(x) is convex downward, with the first inflection point P2 on the curve L1 in FIG. 4A as the boundary, and the first region base end portion R12 corresponds to the section where f′(x)>0 and f″(x)<0 where the function y=f(x) is convex upward. In Fig. 4A, "upward convex" means that a line segment connecting any two points on the curve L1 is always below the curve, while "downward convex" means that a line segment connecting any two points on the curve is always above the curve.

[0057] The tip bulge maximum outer diameter part M1 of the tip bulge 122 is a part where the tip bulge 122 has the maximum outer diameter. The tip bulge maximum outer diameter part M1 is connected to the first region base end part R12 of the first region R1 and the second region tip part R21 of the tip bulge maximum outer diameter part M1. In FIG. 4A, the tip bulge maximum outer diameter part M1 exists as a boundary point between the first region R1 and the second region R2, and coincides with the maximum point P1 on the curve L where the function y=f(x) is maximum and maximum. However, the tip bulge maximum outer diameter part M1 may extend a predetermined length in the long axis direction as a region where the tip bulge 122 has the maximum outer diameter. In FIG. 4A, the tip bulge maximum outer diameter part M1 is f'(x)=0.

[0058] The second region R2 of the tip bulge 122 has a second region tip portion R21 that is convex radially outward and is in a predetermined range from the base end of the tip bulge maximum outer diameter portion M1 to the tip side of the second region R2, and a second region base end portion R22 that is convex radially inward and is on the base end side of the second region tip portion R21. The second region R2 of the tip bulge 122 has a second inflection point P3 on the curve L1 in Figure 4A where f''(x) = 0 and the sign of f''(x) is inverted and the concavity and convexity of the curve L1 changes. The second region tip portion R21 corresponds to the section where f'(x)<0 and f''(x)<0, where the function y=f(x) is upwardly convex, with the second inflection point P3 on the curve L1 in Figure 4A as the boundary, and the second region base portion R22 corresponds to the section where f'(x)<0 and f''(x)>0, where the function y=f(x) is downwardly convex.

[0059] In the lubricous coating layer 120, the outer circumferential surface of the distal bulge 122 is smoothly connected to the outer circumferential surface of the first coating portion 124 by the first region distal end R11 located at the connection portion between the distal bulge 122 and the first coating portion 124. In the lubricous coating layer 120, the outer circumferential surface of the distal bulge 122 is smoothly connected to the outer circumferential surface of the third coating portion 126 by the second region proximal end R22 located at the connection portion between the distal bulge 122 and the third coating portion 126. As a result, in the guidewire 100, the connection portion between the distal bulge 122 and the first coating portion 124 and the connection portion between the distal bulge 122 and the third coating portion 126 of the lubricous coating layer 120 are less likely to get caught on the blood vessel wall or the inner cavity of the catheter, so peeling of the lubricous coating layer 120 can be suppressed.

[0060] By providing the distal bulge 122, the guidewire 100 can suppress unintended movement of the distal bulge 122 toward the base end after passing through the lesion.

[0061] The distal bulge 122 is preferably disposed at the base end of the marker portion 21. Since the marker portion is radiopaque, the surgeon can grasp the position of the distal bulge 122 in the blood vessel under radioscopy. This allows the surgeon to reliably insert the guidewire 100 to a position where the distal bulge 122 passes through the lesion. The distal bulge 122 is preferably disposed at a position 25 mm to 35 mm from the distal end of the guidewire 100.

[0062] As shown in FIG. 4A, the length X1 of the first region R1 along the longitudinal direction of the distal bulge 122 is longer than the length X2 of the second region R2 along the longitudinal direction. This means that the rate of increase in the outer diameter of the first region R1 from the distal end to the proximal end is smaller than the rate of decrease in the outer diameter of the second region R2 from the distal end to the proximal end. In other words, the gradient of the outer peripheral surface of the first region R1 from the distal end to the proximal end is gentler than the gradient of the outer peripheral surface of the second region R2 from the proximal end to the distal end. This allows the distal bulge 122 to easily pass through the lesion when passing through the lesion, and effectively suppresses unintended movement of the guidewire 100 from the lesion to the proximal end after passing through the lesion.

[0063] The length X1 along the major axis of the first region R1 of the tip bulge 122 is 0.7 mm or more and 7.0 mm or less. The length X2 along the major axis of the second region R2 of the tip bulge 122 is 0.3 mm or more and 30 mm or less.

[0064] The length X5 of the tip bulge 122 along the longitudinal direction is 1 mm or more and 10 mm or less. This allows the tip bulge 122 to have sufficient strength to effectively suppress unintended movement along the longitudinal direction of the guidewire 100. When the tubular member 20 is formed of a coil, the length X5 of the tip bulge 122 along the longitudinal direction is greater than the coil pitch. In other words, the tip bulge 122 is formed across multiple adjacent wires of a coil formed by winding wire.

[0065] The tip bulge 122 may be provided around the entire circumferential circumference of the outer circumferential surface of the tubular member 20, or may be provided around only a portion of the circumferential circumference. In other words, the tip bulge 122 may be formed by varying the thickness of the lubricant coating layer 120 around the entire circumferential circumference of the tubular member 20, or may be formed by varying the thickness around only a portion of the circumferential circumference.

[0066] <Proximal bulge> The proximal bulge 123 is a portion of the lubricant coating layer 120 that covers a predetermined region of the wire body 110 on the proximal side of the distal bulge 122 .

[0067] As shown in FIG. 4B, the base end bulge 123 has a third region R3 in which the thickness of the base end bulge 123 increases from the tip to the base end of the wire body 110, a base end bulge maximum outer diameter portion M2 that is continuous with the base end of the third region R3 and in which the outer diameter of the base end bulge 123 is maximum, and a fourth region R4 that is continuous with the base end of the base end bulge maximum outer diameter portion M2 and in which the thickness of the base end bulge 123 decreases from the tip to the base end.

[0068] 4B is a diagram showing a two-axis orthogonal coordinate system in which an axis along the central axis C of the wire body 110 is the x-axis (longitudinal direction of the guidewire 100) and an axis perpendicular to the x-axis and tangent to the tip of the proximal bulge 123 is the y-axis (radial direction of the guidewire 100), with the central axis C of the guidewire 100 placed in a natural state being superimposed on the x-axis and the tip of the third region R3 of the guidewire 100 coinciding with the origin. The proximal bulge 123 has a three-dimensional shape obtained by rotating a curve L2 formed by the outer circumferential surface of the proximal bulge 123 shown in the first quadrant of the orthogonal coordinate system shown in FIG. 4B, about the central axis C as the axis of rotation.

[0069] As shown in FIG. 4B, in the first quadrant of a Cartesian coordinate system, when the function y=f(x) represents the curve L2 formed by the outer peripheral surface of the base end bulge 123 when the guidewire 100 is viewed from the side, the function y=f(x) has a second derivative f''(x) in a certain section of x (x>0). In FIG. 4B, the third region R3 of the base end bulge 123 corresponds to the section of x where f'(x)>0 is satisfied on the tip side of the maximum point P4 (first derivative f'(x)=0) on the curve L2 where the function y=f(x) is maximum. In FIG. 4B, the base end bulge maximum outer diameter section M2 of the base end bulge 123 corresponds to the section of x where f'(x)=0 (maximum point P4). The fourth region R4 of the base end bulge 123 corresponds to a section of x that satisfies f'(x)<0 on the base end side of the maximum point P4 on the curve L2 in FIG. 4B.

[0070] The third region R3 of the base end bulge 123 has a third region tip portion R31 that is convex radially inward in a predetermined range from the tip of the third region R3 to the tip side of the third region R3, and a third region base portion R32 that is convex radially outward on the base end side of the third region tip portion R31. The third region R3 of the base end bulge 123 has a first inflection point P5 on the curve L2 in FIG. 4B where f″(x)=0 and the sign of f″(x) is inverted and the concavity and convexity of the curve L2 changes. The third region tip portion R31 corresponds to the section of f′(x)>0 and f″(x)>0 where the function y=f(x) is convex downward, with the first inflection point P5 on the curve L2 in FIG. 4B as the boundary, and the third region base portion R32 corresponds to the section of f′(x)>0 and f″(x)<0 where the function y=f(x) is convex upward. In Fig. 4B, "upward convex" means that a line segment connecting any two points on the curve L2 is always below the curve, whereas "downward convex" means that a line segment connecting any two points on the curve L2 is always above the curve.

[0071] The base end bulge maximum outer diameter part M2 of the base end bulge part 123 is a part where the base end bulge part 123 has the maximum outer diameter. The base end bulge maximum outer diameter part M2 is connected to the third region base end part R32 of the third region R3 and the fourth region tip part R41 of the fourth region R4. In FIG. 4B, the base end bulge maximum outer diameter part M2 exists as a boundary point between the third region R3 and the fourth region R4, and coincides with the maximum point P4 on the curve L2 where the function y=f(x) is maximum and maximum. However, the base end bulge maximum outer diameter part M2 may extend a predetermined length in the long axis direction as a region where the base end bulge part 123 has the maximum outer diameter. In FIG. 4B, the base end bulge maximum outer diameter part M2 is f'(x)=0.

[0072] The fourth region R4 of the base end bulge 123 has a fourth region tip portion R41 that is convex radially outward and is in a predetermined range from the base end of the base end bulge maximum outer diameter portion M2 to the tip side of the fourth region R4, and a fourth region base end portion R42 that is convex radially inward and is on the base end side of the fourth region tip portion R41. The fourth region R4 of the base end bulge 123 has a second inflection point P6 on the curve L2 in Figure 4B where f''(x) = 0 and the sign of f''(x) is inverted and the concavity and convexity of the curve L2 changes. The fourth region tip portion R41 corresponds to the section where f'(x)<0 and f''(x)<0, where the function y=f(x) is upwardly convex, with the second inflection point P6 on the curve L2 in Figure 4B as the boundary, and the fourth region base portion R42 corresponds to the section where f'(x)<0 and f''(x)>0, where the function y=f(x) is downwardly convex.

[0073] In the lubricous coating layer 120, the outer circumferential surface of the base end bulge 123 is smoothly connected to the outer circumferential surface of the third coating portion 126 by a third region distal end portion R31 located at the connection portion between the base end bulge 123 and the third coating portion 126. In the lubricous coating layer 120, the outer circumferential surface of the base end bulge 123 is smoothly connected to the outer circumferential surface of the second coating portion 125 by a fourth region proximal end portion R42 located at the connection portion between the base end bulge 123 and the second coating portion 125. As a result, in the guidewire 100, the connection portion between the base end bulge 123 and the third coating portion 126 and the connection portion between the base end bulge 123 and the second coating portion 125 of the lubricous coating layer 120 are less likely to get caught on the blood vessel wall or the inner cavity of the catheter, so peeling of the lubricous coating layer 120 can be suppressed.

[0074] When a medical device such as a catheter is passed through a lesion along the guidewire 100, the proximal bulge 123 is disposed slightly proximal to the proximal end of the lesion, thereby making it possible to reduce the gap between the outer circumferential surface of the guidewire 100 and the inner circumferential surface of the catheter at a position near the proximal end of the lesion. This makes it difficult for the guidewire 100 to bend in the catheter lumen, so that the catheter is more likely to be supported by the guidewire 100. In this way, the guidewire 100 can improve the catheter's ability to pass through the lesion. Furthermore, since the guidewire 100 has the proximal bulge 123, even if the guidewire 100 is strongly pushed in to pass through the lesion, it is possible to suppress the occurrence of blood vessel perforation due to unintended movement of the guidewire 100 toward the distal end. This allows the guidewire 100 to improve the safety of the procedure.

[0075] It is preferable that proximal bulge 123 is disposed at a position not less than 90 mm and not more than 250 mm from the distal end of guidewire 100 .

[0076] As shown in FIG. 4B, the length X3 of the third region R3 along the longitudinal direction of the proximal bulge 123 is shorter than the length X4 of the fourth region R4 along the longitudinal direction. This means that the rate of increase in the outer diameter of the third region R3 from the distal end to the proximal end is greater than the rate of decrease in the outer diameter of the fourth region R4 from the distal end to the proximal end. In other words, the gradient of the outer peripheral surface of the third region R3 from the distal end to the proximal end of the proximal bulge 123 is steeper than the gradient of the outer peripheral surface of the fourth region R4 from the proximal end to the distal end. This allows the proximal bulge 123 to effectively suppress unintended movement of the guidewire 100 toward the distal end without impeding the progress of the catheter inserted from the proximal end along the guidewire 100.

[0077] The length X3 of the third region R3 of the base end bulge 123 along the major axis is 0.3 mm or more and 30 mm or less. The length X4 of the fourth region R4 of the base end bulge 123 along the major axis is 0.7 mm or more and 7.0 mm or less.

[0078] The length X6 of the base end bulge 123 along the longitudinal direction is 1 mm or more and 10 mm or less. This allows the base end bulge 123 to have sufficient strength to effectively suppress unintended movement of the guidewire 100 along the longitudinal direction. When the tubular member 20 is formed of a coil, the length X6 of the base end bulge 123 along the longitudinal direction is greater than the coil pitch. In other words, the base end bulge 123 is formed across multiple adjacent wires of a coil formed by winding a wire.

[0079] The base end bulge 123 may be provided around the entire circumferential circumference of the outer circumferential surface of the tubular member 20, or may be provided around only a portion of the circumferential circumference. In other words, the base end bulge 123 may be formed by changing the thickness of the lubricant coating layer 120 around the entire circumferential circumference of the tubular member 20, or may be formed by changing the thickness of a portion of the circumferential circumference.

[0080] In this embodiment, the outer diameter of the tip bulge maximum outer diameter part M1 of the tip bulge part 122 is equal to the outer diameter of the base bulge maximum outer diameter part M2 of the base bulge part 123. However, the outer diameter of the tip bulge maximum outer diameter part M1 and the outer diameter of the base bulge maximum outer diameter part M2 may be different.

[0081] 1, in a swollen state of the lubricating coating layer 120, the maximum radial thickness t1 of the bulging portion 121 is greater than the maximum radial thickness t2 of the first coating portion 124, the maximum radial thickness t3 of the second coating portion 125, and the maximum radial thickness t4 of the third coating portion 126 (t1>t2, t3, t4). The maximum radial thickness t1 of the bulging portion 121 is the maximum radial thickness of the distal bulging portion 122 (the radial thickness of the distal bulging portion maximum outer diameter portion M1) and / or the maximum radial thickness of the proximal bulging portion 123 (the radial thickness of the proximal bulging portion maximum outer diameter portion M2). The maximum radial thickness t1 of the bulging portion 121 is preferably 0.6 μm or more and 12 μm or less, more preferably 0.8 μm or more and 12 μm or less. At this time, the thicknesses t2, t3, and t4 can be set to 0.2 μm or more and 0.8 μm or less, more preferably about 0.4 μm.

[0082] <First coating part> As shown in FIG. 1, the first coating portion 124 is a portion of the lubricant coating layer 120 that is closer to the tip side than the bulge 121. The first coating portion 124 is preferably provided so as to cover the tip of the wire body 110. The first coating portion 124 is formed with a substantially constant thickness. The outer peripheral surface of the first coating portion 124 is smoothly connected to the outer peripheral surface of the bulge 121. It is noted that the first coating portion 124 does not necessarily have to be provided.

[0083] <Second coated part> 1, the second coating portion 125 is a portion of the lubricant coating layer 120 on the base end side of the bulging portion 121. The second coating portion 125 is formed to have a substantially constant thickness. The outer peripheral surface of the second coating portion 125 is smoothly connected to the outer peripheral surface of the bulging portion 121.

[0084] <Third Covering Part> As shown in FIG. 1, the third coating portion 126 is a portion between the distal bulge 122 and the proximal bulge 123 of the lubricating coating layer 120. The third coating portion 126 is formed with a substantially constant thickness. The outer circumferential surface of the third coating portion 126 is smoothly connected to the outer circumferential surfaces of the distal bulge 122 and the proximal bulge 123. The length X7 along the longitudinal direction of the third coating portion 126 is preferably 30 mm or more and 50 mm or less. As a result, when the guidewire 100 is placed in a blood vessel with the distal bulge 122 of the guidewire 100 having passed through a lesion, the proximal bulge 123 is positioned on the proximal side relative to the proximal end of the lesion, so that the lesion can be sandwiched between the distal bulge 122 and the proximal bulge 123. Therefore, the guidewire 100 can suppress unintended movement from the lesion to the distal side and the proximal side, improving the efficiency of the procedure.

[0085] The lubricant coating layer 120 may be composed only of the bulging portion 121. The lubricant coating layer 120 may also have coating portions other than the bulging portion 121, the first coating portion 124, the second coating portion 125, and the third coating portion 126.

[0086] The bulging portion 121 of the lubricant coating layer 120 is formed of a material that can swell when wet. The bulging portion 121 can be formed of a material that can be applied to the lubricant coating layer 41A in the first embodiment described above. The first coating portion 124, the second coating portion 125, and the third coating portion 126 of the lubricant coating layer 120 are preferably formed of the same material as the bulging portion 121. Note that the bulging portion 121, the first coating portion 124, the second coating portion 125, and the third coating portion 126 may be formed of different materials. For example, the bulging portion 121, the second coating portion 125, and the third coating portion 126 may be formed of a material that can swell when wet, and the first coating portion 124 may be partially formed of silicone.

[0087] The lubricant coating layer 120 can be formed by immersing the wire body 110 in a solution containing a material for forming the lubricant coating layer 120, vertically pulling the wire body 110 out of the solution, and then drying it. The wire body 110 may be immersed in the solution once or multiple times.

[0088] When the wire body 110 is pulled out of the solution, a part of the solution adhering to the outer peripheral surface of the wire body 110 forms a liquid pool covering the entire circumference of the tip of the wire body 110 due to the action of surface tension. The bulge 121 can be formed by drying the part of the liquid pool formed at the tip of the wire body 110. When the wire body 110 is pulled out of the solution, the solution adhering to the outer peripheral surface of the wire body 110 flows downward due to gravity, so that the first coating portion 124, the second coating portion 125, and the third coating portion 126 can be formed as layers having a substantially constant thickness. The bulge 121 may also be formed by applying a material for forming the lubricating coating layer 120 to the outer peripheral surface of the wire body 110 at a position where the bulge 121 is to be formed.

[0089] The first coating portion 124 may be formed by removing the material forming the bulge 121, the second coating portion 125 and the third coating portion 126 from the tip of the wire body 110 and applying another material capable of forming a lubricating coating layer 120, such as silicone, to the wire body 110.

[0090] [Example of modification] The guidewire 100 of the present invention can be modified as appropriate as in the following modified examples. In the following description of each modified example, differences from the above-mentioned embodiment are mainly described, and components having the same function as those in other embodiments are denoted by the same or related reference numerals, detailed description is omitted, and no particular mention is made. The configuration, members, and method of use may be the same as those in each embodiment. Furthermore, each modified example can be implemented in combination with other embodiments by appropriately selecting necessary configurations from those shown in each modified example within the scope of the gist of the present invention.

[0091] <Modification Example 1> A guidewire 100C of modified example 1 will be described. Fig. 5A is an enlarged view of the vicinity of the tip portion of the guidewire 100C of modified example 1. Fig. 5B is a partially enlarged view of the vicinity of the tip portion of another form of the guidewire 100C of modified example 1. Fig. 5C is a transverse cross-sectional view of the guidewire 100C of modified example 1 cut in a direction perpendicular to the central axis C.

[0092] 5A and 5B, the guidewire 100C has a lubricant coating layer 120 that covers at least a portion of the wire body 110. The guidewire 100C differs from the above-described configurations in that a bulging portion 121 of the lubricant coating layer 120 is provided on a portion of the wire body 110 in the circumferential direction.

[0093] In the guidewire 100C, as shown in FIGS. 5A and 5B, the distal bulge 122 or the proximal bulge 123 constituting the bulge 121 is provided only partially in the circumferential direction of the wire body 110.

[0094] As shown in Fig. 5A, the bulging portion 121 of the guidewire 100C is formed such that the distal bulging portion 122 is formed by changing the thickness of the lubricant coating layer 120 all around the circumferential direction of the wire body 110, and the proximal bulging portion 123 is formed by changing the thickness of a portion of the circumferential direction of the wire body 110. As shown in Fig. 5B, the bulging portion 121 of the guidewire 100C is formed such that the distal bulging portion 122 is formed by changing the thickness of a portion of the circumferential direction of the wire body 110, and the proximal bulging portion 123 is formed by changing the thickness of the entire circumferential direction of the wire body 110.

[0095] As shown in Fig. 5C, the bulges 121 may be provided at multiple locations at predetermined intervals in the circumferential direction of the wire body 110. Fig. 5C shows a configuration in which multiple bulges 121 are arranged at equal intervals in the circumferential direction of the wire body 110. Note that the bulges 121 do not have to be arranged at equal intervals in the circumferential direction of the wire body 110.

[0096] Guidewire 100C of modified example 1 can suppress unintended movement toward the base end after passing through the lesion due to distal bulge 122 provided on a circumferential portion of wire body 110. Furthermore, guidewire 100C can improve passability of the catheter to the lesion by preventing bending of the catheter lumen that passes through the lesion along guidewire 100C due to proximal bulge 123 provided on a circumferential portion of wire body 110.

[0097] <Modification Example 2> A description will be given of a guidewire 100D according to Modification Example 2. Fig. 6 is an enlarged view of the vicinity of the distal end of a guidewire 100D according to Modification Example 2.

[0098] 6, the guidewire 100D has a lubricant coating layer 120 that covers at least a portion of the wire body 110. The guidewire 100C differs from the above-described configurations in that the proximal bulging portions 123 of the bulging portions 121 of the lubricant coating layer 120 are provided at multiple locations.

[0099] 6, guidewire 100D is provided with base end bulges 123 at two locations on the base end side of tip bulge 122 of bulge 121. Note that guidewire 100D may have additional tip bulges 122, or may have bulges 121, each of which includes a pair of tip bulge 122 and base end bulge 123, provided at multiple locations.

[0100] Guidewire 100D of modified example 2 has distal bulges 122 and / or proximal bulges 123 of bulging portion 121 at multiple locations, making it possible to flexibly accommodate the longitudinal length of the lesion, thereby improving versatility.

[0101] <Modification Example 3> A description will be given of a guidewire 100E according to modified example 3. Fig. 7A is an enlarged view of the periphery of the distal end of guidewire 100E according to modified example 3. Fig. 7B is an enlarged view of the periphery of the distal end of another form of guidewire 100E according to modified example 3.

[0102] 7A and 7B, the guidewire 100E has a lubricant coating layer 120 that covers at least a part of the wire body 110. The guidewire 100E differs from the above-described configurations in that a distal bulge 122 of a bulge 121 of the lubricant coating layer 120 is shifted from the proximal end of the marker portion 21 toward the distal end or proximal end.

[0103] As shown in Fig. 7A, the guidewire 100E can have the distal bulge 122 of the bulge 121 disposed distally of the proximal end of the marker portion 21. As shown in Fig. 7B, the guidewire 100E may have the distal bulge 122 of the bulge 121 disposed proximally of the proximal end of the marker portion 21.

[0104] In guidewire 100E of modified example 3, even if distal bulge 122 of bulge portion 121 is disposed distally or proximally relative to the proximal end of marker portion 21, the position of distal bulge 122 can be grasped based on the position of radiopaque marker portion 21. Therefore, guidewire 100E can be reliably inserted to a position where distal bulge 122 passes through the lesion.

[0105] [Effects] As described above, the guidewire 100 of the present invention has a long wire body 110 and a lubricant coating layer 120 covering at least a portion of the wire body 110, wherein the lubricant coating layer 120 is formed of a material that swells when wet and has at least one bulge 121 having a tip bulge 122 formed by a change in thickness of the lubricant coating layer 120, wherein the tip bulge 122 includes a first region R1, a second region R2 located on the base end side of the first region R1, and a tip bulge maximum outer diameter portion M1 located between the first region R1 and the second region R2, and the length X1 along the longitudinal direction of the first region R1 is longer than the length X2 along the longitudinal direction of the second region R2.

[0106] With this configuration, the guidewire 100 has a tip bulge 122 formed by the lubricant coating layer 120 at the tip of the wire body 110. The tip bulge 122 is formed by changing the thickness of the lubricant coating layer 120, and has an outer circumferential surface including a curved surface that is convex radially outward from the wire body 110. Therefore, the tip bulge 122 can suppress unintended movement of the guidewire 100 after passing through a lesion in a blood vessel. Therefore, the guidewire 100 can improve the efficiency and safety of the procedure.

[0107] In addition, the bulge portion 121 of the guidewire 100 includes a base end bulge portion 123 that is arranged on the base end side relative to the tip bulge portion 122, and the base end bulge portion 123 includes a third region R3, a fourth region R4 that is arranged on the base end side relative to the third region R3, and a base end bulge portion maximum outer diameter portion M2 that is arranged between the third region R3 and the fourth region R4, and the length X3 along the longitudinal direction of the third region R3 may be shorter than the length X4 along the longitudinal direction of the fourth region R4.

[0108] With this configuration, when a medical device such as a catheter is passed through a lesion along the guidewire 100, the proximal bulge 123 is disposed slightly proximal to the proximal end of the lesion, thereby making it possible to reduce the gap between the outer circumferential surface of the guidewire 100 and the inner circumferential surface of the catheter at a position near the proximal end of the lesion. This makes it difficult for the guidewire 100 to bend in the catheter lumen, so that the catheter is more likely to be supported by the guidewire 100. In this way, the guidewire 100 can improve the catheter's ability to pass through the lesion. Furthermore, since the guidewire 100 has the proximal bulge 123, even if the guidewire 100 is strongly pushed in to pass through the lesion, it is possible to suppress the occurrence of blood vessel perforation due to unintended movement of the guidewire 100 toward the distal end. This allows the guidewire 100 to improve the safety of the procedure.

[0109] In addition, the wire body 110 of the guide wire 100 includes a core member 10 and a marker portion 21 that is arranged at the tip of the core member 10 and has radiopacity, and the tip bulge portion 122 may be provided at the base end of the marker portion 21.

[0110] With this configuration, the surgeon can grasp the position of the distal end bulge 122 in the blood vessel under radioscopy, thereby enabling the surgeon to reliably insert the guidewire 100 to a position where the distal end bulge 122 passes through the lesion.

[0111] In addition, the marker portion 21 of the guidewire 100 is a coil formed by winding wire to cover the outer periphery of the core member 10, and the length X7 along the longitudinal direction between the base end of the tip bulge portion 122 and the tip of the base end bulge portion 123 (third covering portion 126) may be longer than the pitch of the coil.

[0112] With this configuration, distal bulge 122 and proximal bulge 123 can be positioned to sandwich the lesion, effectively preventing unintended movement of guidewire 100 along the longitudinal axis.

[0113] Furthermore, the marker portion 21 of the guidewire 100 is a coil formed by winding a wire so as to cover the outer periphery of the core member 10, and the length X5 along the longitudinal direction of the tip bulge portion 122 may be longer than the pitch of the coil.

[0114] Such a configuration allows distal bulge 122 to have sufficient strength to effectively inhibit unintended movement of guidewire 100 along its longitudinal axis. [Explanation of symbols]

[0115] 10 Core member, 20 Tubular member, 21 Marker section, 100, 100A~100E Guide wire, 110 Wire body, 120 Lubricant coating layer, 121 bulge, 122 Tip bulge, 123 proximal bulge, 124 first covering part, 125 second covering part, 126 third covering part, C center axis, R1 1st area, R2 second area, R3 third area, R4 4th area, R11 1st region tip, R12 Proximal end of the first region, R21 2nd region tip, R22 second region proximal end, R31 3rd region tip, R32 3rd region proximal end, R41 4th region tip, R42 4th region proximal end, t1: maximum radial thickness of the bulge, t2: maximum radial thickness of the first coating part; t3 maximum radial thickness of the second coating part, t4 Maximum radial thickness of the third coating part, X1: Length along the major axis direction of the first region R1; X2: Length along the major axis direction of the second region R2; X3: Length along the major axis of the third region R3; X4: Length along the major axis direction of the fourth region R4; X5: Length along the longitudinal axis of the apical bulge; X6: Length along the longitudinal axis of the proximal bulge; X7: Length along the major axis of the third coating section.

Claims

1. A guidewire having a long wire body and a lubricating coating layer covering at least a portion of the wire body, the lubricant coating layer is formed of a material that swells when wet, and has at least one bulge having a tip bulge formed by a change in thickness of the lubricant coating layer; The tip bulge portion includes a first region, a second region disposed on the base end side of the first region, and a tip bulge portion maximum outer diameter portion disposed between the first region and the second region, A guidewire, wherein the length along the longitudinal direction of the first region is greater than the length along the longitudinal direction of the second region.

2. The bulging portion includes a base end bulging portion that is disposed on the base end side relative to the tip end bulging portion, the base end bulge portion includes a third region, a fourth region disposed on the base end side relative to the third region, and a base end bulge portion maximum outer diameter portion disposed between the third region and the fourth region, The guidewire of claim 1 , wherein a length along a longitudinal direction of the third region is shorter than a length along a longitudinal direction of the fourth region.

3. The wire body includes a core member and a marker portion that is disposed at a distal end of the core member and has radiopaque properties, The guidewire according to claim 1 , wherein the distal bulge is provided at a proximal end of the marker portion.

4. the marker portion is a coil formed by winding a wire so as to cover an outer periphery of the core member, The guidewire according to claim 3 , wherein a length along the longitudinal direction between a base end of the distal bulge and a tip end of the proximal bulge is longer than a pitch of the coil.

5. the marker portion is a coil formed by winding a wire so as to cover an outer periphery of the core member, The guidewire according to claim 3 , wherein a length of the tip swelling portion along the longitudinal direction is longer than a pitch of the coil.

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