Guide wire

Abstract

The present invention provides a guide wire that can suppress abrupt changes in stiffness along the long axis near the boundary between the base end of the coil and the core. [Solution] A guide wire 10 having a flexible, elongated core 20 and a coil 40 formed by winding a wire around the outside of the core 20, wherein the base end of the coil 40 and the core 20 are fixed by a base end fixing member 53 having an outer surface with an expanding diameter shape in which the inclination angle θ with respect to the long axis of the core 20 gradually increases from the base end side to the tip side, the coil 40 and the base end fixing member 53 are covered with a coating layer 60 made of a polymer material with lower hardness than the base end fixing member 53, and the coating layer 60 includes a portion on the outer surface of the base end fixing member 53 in which the radial thickness increases from the tip side to the base end side.

Description

Technical Field

[0001] The present invention relates to a guide wire for guiding a long medical instrument to be inserted into a living body.

Background Art

[0002] A guide wire is a medical instrument inserted into a blood vessel to guide a catheter or a stent for performing endovascular treatment to a target position. The guide wire includes a core, a coil covering the tip of the core, and a joint portion for fixing the core and the coil. For example, Patent Document 1 describes a guide wire in which a coil covering the outer periphery of the tip of the core and the core and the coil are joined using solder.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Since the solder for fixing the base end of the coil of the guide wire and the core has high hardness, the rigidity along the long axis direction changes rapidly in the vicinity of the boundary between the base end of the coil of the guide wire and the outer peripheral surface of the core, and kinks may occur in the guide wire.

[0005] The present invention has been made to solve the above problems, and an object thereof is to provide a guide wire capable of suppressing a rapid change in rigidity along the long axis direction in the vicinity of the boundary between the base end of the coil and the core.

Means for Solving the Problems

[0006] The above object is achieved by the invention described in the following (1).

[0007] (1) The guide wire according to the present invention comprises a flexible elongated core and a coil formed by winding a wire around the outside of the core, wherein the base end of the coil and the core are fixed by a base end fixing member having an outer peripheral surface with an expanding diameter shape in which the angle of inclination with respect to the long axis of the core gradually increases from the base end side to the tip side, the coil and the base end fixing member are covered with a coating layer made of a polymer material with lower hardness than the base end fixing member, and the coating layer is characterized in that the radial thickness on the outer peripheral surface of the base end fixing member increases from the tip side to the base end side. [Effects of the Invention]

[0008] The guide wire described in (1) above allows for a larger radial thickness of the coating layer, which is less hard and more flexible than the material forming the base end fixing member, in the base end fixing member. This suppresses abrupt changes in rigidity along the long axis near the boundary between the base end and the core of the coil.

[0009] (2) In the guide wire described in (1) above, the base end of the coil may have a gap between the wires of adjacent coils. This allows the fluid fixing material dropped onto the base end of the coil to flow into the gap between the wires of the coil toward the tip when fixing the coil to the core, making it easy to form an enlarged diameter shape of the base end fixing member. Furthermore, as the fixing material flows through the gap between the wires of the coil over a predetermined range from the base end toward the tip, the area in contact between the coil, the core and the fixing material increases, so the guide wire can make the fixing of the base end of the coil to the outer surface of the core by the base end fixing member more robust.

[0010] (3) In the guide wire described in (1) or (2) above, the coating layer may include a portion on the outer circumferential surface of the proximal end of the proximal fixing member in which the radial thickness of the coating layer is reduced. This prevents the tip of the catheter inserted from the proximal end from getting caught at the boundary between the proximal fixing member and the outer circumferential surface of the core.

[0011] (4) In the guide wire described in any one of (1) to (3) above, the polymer material forming the coating layer may be a hydrophilic polymer. This improves the lubricity of the guide wire when wet. In particular, because the base end fixing member has an expanding diameter shape with a gradually increasing inclination angle toward the tip, the thickness of the coating layer on the outer surface of the base end fixing member can be increased. As a result, the lubricity of the guide wire near the boundary between the base end of the coil and the core is improved, and the tip of the catheter inserted from the base end side of the guide wire is prevented from getting caught on the boundary between the base end of the coil of the guide wire and the outer surface of the core.

[0012] (5) In the guide wire described in any one of (1) to (3) above, the polymer material forming the coating layer may be a thermoplastic elastomer. This allows the guide wire to have a flexible and smooth outer surface. Furthermore, since the thickness of the flexible thermoplastic elastomer on the outer surface of the base end fixing member can be increased, abrupt changes in rigidity along the long axis near the boundary between the base end and the core of the coil can be suppressed. [Brief explanation of the drawing]

[0013] [Figure 1] This is a plan view showing a guide wire according to the first embodiment. [Figure 2] This is a cross-sectional view showing a guide wire according to the first embodiment. [Figure 3] This is a cross-sectional view showing an enlarged view of the vicinity of the base end fixing member of the guide wire according to the first embodiment. [Figure 4] This is a cross-sectional view showing a guide wire according to the second embodiment. [Figure 5] This is a cross-sectional view showing an enlarged view of the vicinity of the base end fixing member of the guide wire according to the second embodiment. [Modes for carrying out the invention]

[0014] Embodiments of the present invention will be described below with reference to the drawings. Note that the dimensions in the drawings may be exaggerated for illustrative purposes and may differ from the actual dimensions. In addition, in this specification and drawings, components having substantially the same functional configuration are denoted by the same reference numerals to avoid redundant explanations. In this specification, the end of the guidewire that is inserted into the blood vessel will be referred to as the "tip end," and the end that is operated will be referred to as the "proximal end."

[0015] Guidewires are used to guide catheters into blood vessels in organs such as the heart, brain, lower limbs, liver, prostate, and uterus.

[0016] <First Embodiment> As shown in Figures 1 to 3, the guide wire 10 according to the first embodiment comprises a long core 20, a coil 40 surrounding the tip of the core 20, a fixing member 50 for fixing the coil 40 to the core 20, and a covering layer 60.

[0017] The core 20 comprises a base core 21 and a tip core 30 located on the tip side of the base core 21. The base core 21 comprises a main core 22 and a base coupling portion 23 located at the tip of the main core 22. The outer diameter of the main core 22 is approximately constant. The outer diameter of the base coupling portion 23 is larger than the outer diameter of the main core 22.

[0018] The distal core 30 is an elongated member extending from the distal end of the proximal core 21 toward the distal end side of the guide wire 10. The distal core 30 includes, from the proximal end toward the distal end of the distal core 30, a distal coupling portion 31, a large-diameter portion 32, a first tapered portion 33, a medium-diameter portion 34, a second tapered portion 35, a small-diameter portion 36, a wedge portion 37, and a flat plate portion 38. The distal coupling portion 31 is a portion joined to the proximal coupling portion 23 of the proximal core 21. The outer diameter of the distal coupling portion 31 is larger than the outer diameter of the large-diameter portion 32 and coincides with the outer diameter of the proximal coupling portion 23. The outer diameter of the large-diameter portion 32 is substantially constant and substantially coincides with the outer diameter of the main body core 22. The outer diameters of the joined distal coupling portion 31 and proximal coupling portion 23 are larger than the outer diameters of the main body core 22 and the large-diameter portion 32. Therefore, the joining strength between the distal core 30 and the proximal core 21 can be increased. The outer diameter of the first tapered portion 33 decreases from the large-diameter portion 32 toward the medium-diameter portion 34. The outer diameter of the medium-diameter portion 34 is constant. The outer diameter of the medium-diameter portion 34 is smaller than the outer diameter of the large-diameter portion 32. The outer diameter of the second tapered portion 35 decreases from the medium-diameter portion 34 toward the small-diameter portion 36. The outer diameter of the small-diameter portion 36 is constant. The outer diameter of the small-diameter portion 36 is smaller than the outer diameter of the medium-diameter portion 34. The wedge portion 37 has a thickness that decreases and a width that increases from the distal end of the small-diameter portion 36 toward the flat plate portion 38. The flat plate portion 38 has a constant thickness and a constant width.

[0019] The total length of the guide wire 10 in the longitudinal direction is, for example, 300 mm to 5000 mm. The outer diameter of the proximal core 21 is, for example, 0.15 mm to 2 mm. Also, the outer diameter of the distal end portion of the distal core 30 is, for example, 0.1 mm to 1 mm.

[0020] The core 20 can be formed of various metal materials such as stainless steels such as SUS302, SUS304, SUS303, SUS316, SUS316L, SUS316J1, SUS316J1L, SUS405, SUS430, SUS434, SUS444, SUS429, SUS430F, piano wire, cobalt-based alloys, superelastic alloys such as nickel-titanium alloys. The distal core 30 is preferably formed of a nickel-titanium alloy, and the proximal core 21 is preferably formed of stainless steel. Note that the distal core 30 and the proximal core 21 may be formed of the same material.

[0021] The coil 40 includes a tip coil 41 and a base coil 42 disposed on the base end side of the tip coil 41. The tip coil 41 and the base coil 42 surround the tip portion of the tip core 30 of the core 20 and are fixed to the tip core 30. The tip coil 41 and the base coil 42 are arranged coaxially with the tip core 30 and spaced apart from the outer peripheral surface of the tip portion of the core 20.

[0022] It is preferable that the outer diameter of the tip coil 41 is constant from the tip to the base end, but it does not have to be constant. For example, the tip coil 41 may include a tapered shape in which the outer diameter decreases from the base end toward the tip. Similarly, it is preferable that the outer diameter of the base coil 42 is constant from the tip to the base end, but it does not have to be constant. The outer diameter of the tip coil 41 and the outer diameter of the base coil 42 are substantially equal. The outer diameters of the tip coil 41 and the base coil 42 are, for example, 0.15 mm to 2 mm. The length of the tip coil 41 is, for example, 3 mm to 60 mm. The length of the base coil 42 is, for example, 10 mm to 400 mm. Note that the coil 40 may be formed by one coil or may be formed by three or more coils.

[0023] The base end portion of the tip coil 41 and the tip end portion of the base coil 42 are intertwined. That is, in the portion where the tip coil 41 and the base coil 42 are intertwined, the coil wires of the base end portion of the tip coil 41 and the coil wires of the tip end portion of the base coil 42 are alternately arranged in the long axis direction. By intertwining the tip coil 41 and the base coil 42 in this way, separation between the tip coil 41 and the base coil 42 is suppressed. The tip coil 41 and the base coil 42 have the same winding direction so that they can be intertwined. The length at which the base end portion of the tip coil 41 and the tip end portion of the base coil 42 are intertwined is, for example, 0.1 mm to 2 mm.

[0024] The coil wire of the tip coil 41 is loosely wound in a spiral shape with gaps between adjacent coil wires. The outer diameter of the coil wire of the tip coil 41 is, for example, 20 μm to 90 μm, preferably 30 μm to 70 μm. The gap between adjacent coil wires of the tip coil 41 is, for example, 1 μm to 10 μm.

[0025] The base coil 42 has a first tightly wound section 43 and a second tightly wound section 45, in which the coil wire is tightly wound in a spiral shape without gaps between adjacent coil wires, and a first loosely wound section 44 and a second loosely wound section 46, in which the coil wire is loosely wound in a spiral shape with gaps between adjacent coil wires. The first tightly wound section 43 is located at the tip of the base coil 42. The first loosely wound section 44 is located on the base end side of the first tightly wound section 43. The second tightly wound section 45 is located on the base end side of the first loosely wound section 44. The second loosely wound section 46 is located at the base end of the base coil 42, on the base end side of the second tightly wound section 45. The outer diameter of the coil wire of the base coil 42 is, for example, 20 μm to 90 μm, preferably 30 μm to 70 μm.

[0026] The coil wires forming the tip coil 41 and the base coil 42 can be made from metals such as stainless steel, superelastic alloys, cobalt-based alloys, gold, platinum, tungsten, or alloys containing these metals. The coil wire may consist of a single wire or a stranded wire formed by twisting two or more wires together. Furthermore, the cross-sectional shape of the coil wire is preferably circular, but may also be elliptical, rectangular, or the like.

[0027] The tip coil 41 is preferably formed from a coil wire made of a material that is more flexible and radiopaque than the base coil 42. The tip coil 41 can be made from, for example, metallic materials such as gold, platinum, and tungsten, and alloys such as platinum-nickel alloys containing these materials. The base coil 42 can be made from, for example, stainless steel. The materials of the coil wires forming the tip coil 41 and the base coil 42 may be the same.

[0028] The fixing member 50 is a member that fixes the coil 40 to the core 20, and the fixing member 50 comprises a tip fixing member 51, an intermediate fixing member 52, and a base fixing member 53. The tip fixing member 51 fixes the tip portion of the tip coil 41 to the flat plate portion 38 of the tip core 30. The tip fixing member 51 is located at the very tip of the guide wire 10 and is formed to have a substantially hemispherical shape and a smooth surface. The intermediate fixing member 52 fixes the base portion of the tip coil 41, the tip portion of the base coil 42, and a cylindrical member 54 positioned between the inner circumferential surface 58 of the coil 40 and the outer circumferential surface of the core 20 to the second tapered portion 35 of the tip core 30. The base fixing member 53 fixes the base portion of the base coil 42 to the medium diameter portion 34 of the tip core 30. The tip fixing member 51, intermediate fixing member 52, and base fixing member 53 are formed from a fixing material consisting of adhesive, brazing material, solder, etc.

[0029] The base end fixing member 53 is provided to cover the outer circumferential surface of the base end of the coil 40 and the outer circumferential surface of the core 20. The outer circumferential surface of the base end fixing member 53 has an expanding diameter shape, where, in a longitudinal cross-section including the long axis of the core 20, the inclination angle θ with respect to the long axis of the core 20 gradually increases from the base end side toward the tip side, beyond the base end of the coil 40. In other words, the base end fixing member 53 has a concave curved surface in a longitudinal cross-section including the long axis of the core 20. As a result, the radial thickness of the base end fixing member 53 decreases from the tip side toward the base end. Also, at the base end of the coil 40, the fixing material forming the base end fixing member 53 is inserted into the gap between adjacent coil wires. The boundary outer circumferential surface 55 between the outer circumferential surface of the base end fixing member 53 where the inclination angle θ increases toward the tip side and the outer circumferential surface where the outer diameter is substantially constant toward the tip side is formed as a smooth outer circumferential surface that is convex radially outward.

[0030] In a longitudinal section of the core 20 including the long axis, the position of the inflection point 57 between the concave curved base outer surface 56 and the convex curved boundary outer surface 55 is not particularly limited. However, in order to ensure a wide base outer surface 56, it may be radially outward from the position of the inner surface 58 of the coil 40, or radially outward from the position of the wire center 59 of the coil wire forming the coil 40. The position of the inflection point 57 may also be radially inward from or at the position of the inner surface 58 of the coil 40.

[0031] The expanding diameter shape of the base end fixing member 53, in which the inclination angle θ changes, can be formed by dropping a fluid fixing material near the base end of the coil 40. When fixing the coil 40 to the core 20, if a fluid fixing material is dropped near the base end of the coil 40, the fixing material will bend between the base end of the coil 40 and the outer circumferential surface of the core 20 due to the surface tension of the fixing material, forming a concave meniscus. By solidifying the fixing material in this state, a base end fixing member 53 having an expanding diameter shape in which the inclination angle θ gradually increases toward the tip can be formed. Furthermore, by providing a gap between adjacent coil wires at the base end of the coil 40, the fluid fixing material dropped toward the tip flows into the gap between the coil wires, and the amount becomes appropriate without forming a liquid reservoir between the base end of the coil 40 and the outer circumferential surface of the core 20, so that the expanding diameter shape of the base end fixing member 53 in which the inclination angle θ changes can be easily formed. Furthermore, as the fixing material flows through the gaps between the coil wires over a predetermined range from the base end to the tip end of the coil 40, the area in contact with each other increases. As a result, the guide wire 10 can more firmly fix the base end of the coil 40 to the outer surface of the core 20 by the base end fixing member 53. Note that the expanding diameter shape of the base end fixing member 53, in which the inclination angle θ gradually increases towards the tip end, may be formed by grinding the outer surface after the fixing material has solidified.

[0032] The fixing material, in a fluid state, preferably has high wettability with respect to the core 20. This allows the fixing material dropped near the base end of the coil 40 to penetrate the gap between the outer surface of the core 20 and the inner surface 58 of the coil 40, easily forming a concave meniscus.

[0033] The cylindrical member 54 is a member that reduces the gap between the inner circumferential surface 58 of the coil 40 and the outer circumferential surface of the core 20, and fixes the coil 40 coaxially with respect to the core 20. The cylindrical member 54 is made of, for example, metal or resin. The outer diameter of the tip of the cylindrical member 54 is smaller than the outer diameter of the base of the cylindrical member 54. This allows the tip coil 41 with a small inner diameter and the base coil 42 with a large inner diameter to be fixed coaxially with respect to the core 20. The relative sizes of the outer diameters of the tip and base of the cylindrical member 54 may be appropriately selected according to the inner diameters of the tip coil 41 and the base coil 42. Furthermore, the guide wire 10 does not necessarily have to be equipped with a cylindrical member 54.

[0034] The coating layer 60 comprises a first coating layer 61 and a second coating layer 62. The first coating layer 61 covers the coil 40, the fixing member 50, and a portion of the core 20. The second coating layer 62 covers the base end of the tip core 30 and the base end core 21.

[0035] The first coating layer 61 is formed from a polymer material with lower hardness than the base end fixing member 53. Preferably, the first coating layer 61 is formed from a hydrophilic polymer. Examples of hydrophilic polymers that form the first coating layer 61 include cellulose polymers, polyethylene oxide polymers, maleic anhydride polymers (for example, maleic anhydride copolymers such as methyl vinyl ether-maleic anhydride copolymer), acrylamide polymers (for example, polyacrylamide, glycidyl methacrylate-dimethylacrylamide block copolymer), water-soluble nylon, polyvinyl alcohol, polyvinylpyrrolidone, and their derivatives.

[0036] The radial thickness of the first coating layer 61 on the outer circumferential surface of the base end fixing member 53 increases from the tip side towards the base end at the tip of the base end fixing member 53, and decreases from the tip side towards the base end at the base end of the base end fixing member 53. Specifically, the radial thickness of the first coating layer 61 on the outer circumferential surface of the base end fixing member 53 increases from the tip of the base end outer circumferential surface 56 toward the apex T of the recess as the inclination angle θ of the outer circumferential surface of the base end fixing member 53 changes. Furthermore, the radial thickness of the first coating layer 61 on the outer circumferential surface of the base end fixing member 53 decreases from the apex T of the recess toward the base end of the base end outer circumferential surface 56 as the inclination angle θ of the outer circumferential surface of the base end fixing member 53 changes. In other words, the radial thickness of the first coating layer 61 on the outer circumferential surface of the base end fixing member 53 is maximum near the apex T of the recess. The apex T of the recess is the position furthest from the line connecting the tip and base of the recess in a longitudinal section including the long axis of the core 20. Since the material forming the first coating layer 61 is less hard and more flexible than the material forming the base fixing member 53, the guide wire 10 can suppress abrupt changes in rigidity along the long axis near the boundary between the base end of the coil 40 and the core 20. Furthermore, since the radial thickness of the first coating layer 61 is reduced on the outer circumferential surface of the base end of the base fixing member 53, the guide wire 10 can prevent the tip of the catheter inserted from the base end from catching on the boundary between the base fixing member 53 and the outer circumferential surface of the core 20. Note that the radial thickness of the first coating layer 61 on the outer circumferential surface of the base fixing member 53 may increase from the tip to the base of the outer circumferential surface 56 of the base fixing member 53.

[0037] The first coating layer 61 can be formed by immersing the core 20, on which the coil 40 is placed, from the tip side to near the base end of the base end fixing member 53 in a solution containing a hydrophilic polymer that forms the first coating layer 61, then pulling the core 20 up vertically and drying it. Because the base end fixing member 53 has an expanding diameter shape in which the inclination angle θ gradually increases toward the tip side, when the core 20 on which the coil 40 is placed is pulled out of the solution, the solution forms a liquid reservoir on the concave curved surface of the base end fixing member 53. As a result, the radial thickness of the first coating layer 61 increases near the apex T of the concave part of the base end fixing member 53. Furthermore, the thickness of the first coating layer 61 on the outer circumferential surface of the base end fixing member 53 can be increased compared to the case where the inclination angle θ is constant. Therefore, the guidewire 10 has improved lubrication near the boundary between the proximal end of the coil 40 and the core 20, which prevents the tip of the catheter inserted from the proximal end side of the guidewire 10 from getting caught on the boundary between the proximal end of the coil 40 of the guidewire 10 and the outer surface of the core 20.

[0038] The second coating layer 62 is preferably formed from a low-friction material. The second coating layer 62 can be formed from, for example, a fluororesin such as polytetrafluoroethylene (PTFE), a silicone resin, or the hydrophilic polymer mentioned above.

[0039] As described above, the guide wire 10 according to the first embodiment is a guide wire 10 having a flexible elongated core 20 and a coil 40 formed by winding a wire around the outside of the core 20, wherein the base end of the coil 40 and the core 20 are fixed by a base end fixing member 53 having an outer peripheral surface with an expanding diameter shape in which the inclination angle θ with respect to the long axis of the core 20 gradually increases from the base end side to the tip side, the coil 40 and the base end fixing member 53 are covered with a coating layer 60 (first coating layer 61) made of a polymer material with lower hardness than the base end fixing member 53, and the coating layer 60 (first coating layer 61) includes a portion on the outer peripheral surface of the base end fixing member 53 in which the radial thickness increases from the tip side to the base end side. As a result, the guide wire 10 can increase the radial thickness of the first coating layer 61, which is less hard and more flexible than the material forming the base end fixing member 53, thereby suppressing abrupt changes in rigidity along the long axis near the boundary between the base end of the coil 40 and the core 20.

[0040] Furthermore, the base end of the coil 40 may have a gap between the wires of adjacent coils 40. This allows the fluid fixing material dripped onto the base end of the coil 40 to flow towards the tip side into the gap between the wires of the coil 40 when fixing the coil 40 to the core 20, thus easily forming the enlarged diameter shape of the base end fixing member 53. Also, as the fixing material flows through the gap between the wires of the coil 40 over a predetermined range from the base end to the tip side, the area in contact between the coil 40, the core 20, and the fixing material increases, the guide wire 10 can more firmly fix the base end of the coil 40 to the outer surface of the core 20 by the base end fixing member 53.

[0041] Furthermore, the coating layer 60 (first coating layer 61) may include a portion on the outer circumferential surface of the proximal end of the proximal fixing member in which the radial thickness of the coating layer 60 (first coating layer 61) is reduced. This prevents the tip of the catheter inserted from the proximal end of the guide wire 10 from getting caught at the boundary between the proximal fixing member 53 and the outer circumferential surface of the core 20.

[0042] Furthermore, the polymer material forming the coating layer 60 (first coating layer 61) may be a hydrophilic polymer. This improves the lubricity of the guidewire 10 when wet. In particular, because the base end fixing member 53 has an expanding diameter shape that gradually increases the inclination angle θ toward the tip, the guidewire 10 can increase the thickness of the first coating layer 61 on the outer surface of the base end fixing member 53. As a result, the guidewire 10 has improved lubricity near the boundary between the base end of the coil 40 and the core 20, and it is possible to prevent the tip of the catheter inserted from the base end side of the guidewire 10 from getting caught on the boundary between the base end of the coil 40 of the guidewire 10 and the outer surface of the core 20.

[0043] <Second Embodiment> As shown in Figures 4-5, the guide wire 100 according to the second embodiment comprises a long core 110, a coil 120 arranged so as to be in close contact with the outer circumferential surface of the tip of the core 110, a fixing member 130 for fixing the coil 120 to the core 110, and a covering layer 140 covering the core 110 and the coil 120.

[0044] The core 110 comprises a small-diameter tip portion 111 having a substantially constant outer diameter along the long axis, a tapered portion 112 positioned on the base end side of the small-diameter tip portion 111, and a large-diameter base portion 113 positioned on the base end side of the tapered portion 112 and having a substantially constant outer diameter along the long axis. The small-diameter tip portion 111, the tapered portion 112, and the large-diameter base portion 113 are integrally formed from the same material. The core 110 can be formed from materials selected from the same materials as the core 20 of the first embodiment described above, and it is preferable to form it from various metallic materials such as various stainless steels and superelastic alloys such as nickel-titanium alloys.

[0045] The lengths of each part of the core 110 along the long axis are, for example, 5mm to 20mm for the small diameter tip section 111, 50mm to 600mm for the entire tapered section 112, and 100mm to 5000mm for the large diameter base section 113.

[0046] The small-diameter tip portion 111 has a smaller outer diameter than the tapered portion 112 and the large-diameter base portion 113. The large-diameter base portion 113 has a larger outer diameter than the small-diameter tip portion 111 and the tapered portion 112. For example, the outer diameter of the small-diameter tip portion 111 is 0.06 mm to 0.10 mm, and the outer diameter of the large-diameter base portion 113 is 0.20 mm to 0.50 mm. The tapered portion 112 has an outer diameter that increases toward the base end, and continuously transitions the rigidity of the core 110 between the small-diameter tip portion 111 and the large-diameter base portion 113. In the tapered portion 112, the core inclination angle α, which is the angle between the major axis of the core 110 and the outer circumferential surface of the core 110 in a longitudinal cross-section passing through the major axis of the core 110, is preferably 0.001 degrees to 10 degrees. The tapered portion 112 may be formed by a plurality of tapered portions 112 having different core inclination angles α in succession.

[0047] The core 110 may have a shaping portion at its tip that can be shaped by plastic deformation. The shaping portion is preferably formed in a range that includes the small-diameter tip portion 111 and the tip of the tapered portion 112. The length of the shaping portion along the long axis is preferably 20 mm or more, and more preferably 25 mm or more. The shaping portion is formed by heat-treating the core 110, which is made of a superelastic material such as a nickel-titanium alloy, to reduce or eliminate its superelasticity.

[0048] The coil 120 has a first loosely wound section 121 and a second loosely wound section 122 in which the coil wire is loosely wound in a spiral with gaps between adjacent coil wires, and a tightly wound section 123 in which the coil wire is tightly wound in a spiral without gaps between adjacent coil wires. The first loosely wound section 121 is located at the tip of the coil 120, and the second loosely wound section 122 is located at the base of the coil 120. The tightly wound section 123 is located in the middle section between the first loosely wound section 121 and the second loosely wound section 122. Note that the coil wire at the tip and base of the coil 120 may be tightly wound, or the coil wire in the middle section of the coil 120 may be loosely wound.

[0049] The fixing member 130 comprises a tip fixing member 131 that fixes the tip of the coil 120 to the tip of the core 110, and a base fixing member 132 that fixes the base end of the coil 120 to the tapered portion 112 of the core 110. The tip fixing member 131 and the base fixing member 132 are formed from a fixing material such as adhesive, brazing material, or solder. In the tip fixing member 131 and the base fixing member 132, the fixing material forming the tip fixing member 131 and the base fixing member 132 is contained within the gaps between adjacent coil wires. The outer circumferential surface of the base fixing member 132 has a base outer circumferential surface 133 that is wider in diameter from the base end towards the tip, with respect to the major axis of the core 110 gradually increasing from the base end towards the tip. The boundary outer surface 134 between the outer surface of the base end fixing member 132, where the inclination angle θ increases toward the tip, and the outer surface, where the outer diameter decreases toward the tip, is formed as a smooth outer surface that is convex radially outward.

[0050] In this embodiment, the coating layer 140 covers the entire core 110, coil 120, and fixing member 130. The outer diameter of the coating layer 140 may decrease towards the tip, or it may be substantially constant from the tip to the base.

[0051] The coating layer 140 includes a first coating layer 141 provided on the outer circumferential surfaces of the core 110, coil 120, and fixing member 130, and a second coating layer 142 provided on the outer circumferential surface of the first coating layer 141.

[0052] The first coating layer 141 is formed from a polymer material with lower hardness than the base end fixing member 132. The polymer material forming the first coating layer 141 is, for example, a highly flexible resin such as polyurethane, polyethylene, polyvinyl chloride, polyester, polypropylene, polyamide, polystyrene, fluororesin, silicone resin, or elastomers of each (e.g., thermoplastic elastomers such as polyester elastomer) and composite materials thereof. Furthermore, it is preferable that the first coating layer 141 is radiopaque. For example, the first coating layer 141 is formed from a thermoplastic elastomer containing radiopaque particles made of tungsten, bismuth, barium, etc. Note that the first coating layer 141 may be arranged to cover only a portion of the core 110 and coil 120.

[0053] The outer surface of the first coating layer 141 is formed smoothly without creating any steps at the base end of the coil 120. Furthermore, the radial thickness of the first coating layer 141 on the outer surface of the base end fixing member 132 increases from the tip side to the base end side as the inclination angle θ of the outer surface of the base end fixing member 132 changes.

[0054] The first coating layer 141 can be formed by extruding a polymer material onto the outer surface of the core 110 on which the coil 120 is arranged. Alternatively, the first coating layer 141 may be formed by immersing the core 110 on which the coil 120 is arranged in a solution containing the polymer material that forms the first coating layer 141, starting from the tip side, then pulling it up vertically and drying it.

[0055] The entire or a portion of the outer surface of the first coating layer 141 is covered with a second coating layer 142 made of a polymer material. The second coating layer 142 can be made of a hydrophilic polymer similar to the material that forms the first coating layer 61 in the first embodiment.

[0056] As described above, in the second embodiment, the guide wire 100, similar to the first embodiment, has the base end of the coil 120 and the core 110 fixed by a base end fixing member 132 having an outer circumferential surface with an expanding diameter shape in which the inclination angle θ with respect to the long axis of the core 110 gradually increases from the base end side to the tip side. The coil 120 and the base end fixing member 132 are covered with a coating layer 140 (first coating layer 141) made of a polymer material with lower hardness than the base end fixing member 132, and the radial thickness of the coating layer 140 (first coating layer 141) on the outer circumferential surface of the base end fixing member 132 increases from the tip side to the base end side. As a result, in the guide wire 100, the radial thickness of the first coating layer 141, which is less hard and more flexible than the material forming the base end fixing member 132, can be increased, thereby suppressing abrupt changes in rigidity along the long axis near the boundary between the base end of the coil 120 and the core 110.

[0057] Furthermore, the polymer material forming the coating layer 40 (first coating layer 141) may be a thermoplastic elastomer. This allows the guide wire 100 to have a flexible and smooth outer surface. In addition, since the thickness of the flexible thermoplastic elastomer on the outer surface of the base end fixing member 132 can be increased, abrupt changes in rigidity along the long axis near the boundary between the base end of the coil 120 and the core 110 can be suppressed.

[0058] It should be noted that the present invention is not limited to the embodiments described above, and various modifications can be made by those skilled in the art within the technical framework of the present invention. For example, the form of the guide wire is not limited as long as a coil is fixed to the tip of the core. [Explanation of Symbols]

[0059] 10, 100 guide wires 20, 110 cores 40, 120 coils 41 Tip coil 42 Base End Coil 43 The first tightly wound section 44, 121 First sparse section 45 The second tightly wound section 46, 122 Second sparse section 53, 132 Base end fixing member 60, 140 coating layer 61, 141 1st coating layer 62, 142 Second coating layer 123 Closely wrapped part θ Tilt angle

Claims

1. A guide wire having a flexible, elongated core and a coil formed by winding a wire around the outside of the core, The base end of the coil and the core are fixed together by a base end fixing member having an outer surface with an expanding diameter shape in which the angle of inclination with respect to the major axis of the core gradually increases from the base end side to the tip end side. The coil and the base end fixing member are covered with a coating layer made of a polymer material with lower hardness than the base end fixing member. The guide wire is characterized in that the coating layer includes a portion on the outer circumferential surface of the base end fixing member in which the radial thickness increases from the tip side to the base end side.

2. The guide wire according to claim 1, characterized in that the base end of the coil has a gap between the wires of adjacent coils.

3. The guide wire according to claim 1 or 2, characterized in that the coating layer includes a portion on the outer circumferential surface of the base end of the base end fixing member in which the radial thickness of the coating layer decreases.

4. The guide wire according to claim 1 or 2, characterized in that the polymer material forming the coating layer is a hydrophilic polymer.

5. The guide wire according to claim 1 or 2, characterized in that the polymer material forming the coating layer is a thermoplastic elastomer.

Images