JP2005224467A - Medical guide wire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a medical guide wire of excellent characteristics for which a proximal end side is relatively strong, a distal end side is continuously soft, the flexibility of a distal end part is excellent, rotation torque on the proximal end side is excellently transmitted to the distal end side, torque transmission is excellent, insertion resistance is small, and breakdown phenomenons are reduced even when it is thinned. <P>SOLUTION: The medical guide wire 2 is provided with a core wire 4 having distal end side small diameter parts 22, 24 and 26 and a proximal end side large diameter part 20 having an outer diameter relatively larger than the distal end side small diameter parts. The core wire is constituted of a super high elasticity alloy with the elastic distortion characteristics that Young's modulus in a longitudinal direction is ≥220kN/mm<SP>2</SP>and elongation is ≥1.5%. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a medical guide wire for guiding a medical instrument such as a catheter used for treatment or examination to a predetermined position in a body cavity such as a blood vessel. More specifically, the proximal end side is relatively strong. The distal end side is continuously soft, the distal end portion is flexible, the rotational torque on the proximal end side is transmitted to the distal end side, and the torque transmission is good. Further, the present invention relates to a medical guide wire having a low insertion resistance and excellent characteristics that does not cause a crunch.

  In some cases, it may be necessary to insert the catheter into place in the blood vessel for treatment or examination. The catheter is generally excellent in flexibility, and it is difficult to push the catheter into a predetermined position inside the blood vessel by itself. Therefore, it is common practice to insert a guide wire into the blood vessel in advance and guide the catheter to a predetermined position in the blood vessel along the guide wire.

  The main requirement for guidewires is that they have sufficient pushing characteristics to push them through the patient's vasculature or other lumens of the body without kinking them. However, they also need to be sufficiently flexible so as not to damage the blood vessels through them or other lumens of the body.

  Efforts have been made to achieve both the push-in characteristics and flexibility of the guide wire and make them more suitable for use (see Patent Document 1 and Patent Document 2). However, these two properties are, in many parts, the exact opposite of each other, making one larger makes the other smaller.

  Conventional guidewires for PTCA and other vascular surgeries are typically placed around an elongated wire core having one or more tapered sections near its distal end and a distal portion of the wire core A flexible coil spring. By setting it as such a structure, it aims at coexistence of sufficient indentation characteristic and the flexibility in a distal end part.

  Conventionally, the wire core wire and the coil spring are made of stainless steel, and the elastic elongation is about 0.9%. Therefore, the tip portion is not sufficiently flexible, and is inserted into a blood vessel having a strong bend of R = 20 mm or less. In many cases, permanent deformation occurs and subsequent operation in the blood vessel becomes difficult.

  It has also been proposed to use a superelastic alloy such as nickel / titanium, which exhibits superelastic properties, for the guide wire. When a load is applied, a property that undergoes a relatively large deformation with a constant stress, but recovers from the deformation when the load is removed is usually called “superelasticity”.

  However, if the entire guide wire is made of a superelastic alloy, the elastic modulus of the superelastic alloy is relatively low, so it becomes easy to bend to the proximal end (base end) of the guidewire, and the guidewire is pushed in. There is a problem with the characteristics.

  In addition, a guide wire in which the base end portion of the guide wire is made of stainless steel and the tip portion is made of a superelastic alloy has been proposed, but it is difficult to join the stainless metal and the superelastic alloy, and the joining is insufficient. The strength of the joint becomes a problem. Further, the rigidity changes abruptly before and after the joint, which often makes wire manipulation difficult.

In recent years, thin catheters aiming at approaches to thin blood vessels such as cerebral blood vessels have begun to become widespread, and accordingly, guide wires that are thinner are also required. However, if the stainless steel or superelastic metal conventionally used for the guide wire is reduced in diameter as it is, the bending rigidity on the hand side is lowered, and as a result, there is a problem that the indentation characteristic is lowered.
Japanese Patent Laid-Open No. 60-168466 JP 60-7862 A

  The present invention has been made in view of such circumstances, and the proximal end side is relatively strong, the distal end side is continuously flexible, the distal end portion is highly flexible, and the proximal end side is rotated. To provide a medical guide wire with excellent characteristics that torque is transmitted to the distal end side, torque transmission is good, insertion resistance is small, and even if it is made thin, it does not cause crumble (lumbar fracture) phenomenon. Objective.

In order to solve the above problems, the inventors have intensively studied the characteristics of each material as a guide wire, and the wire core wire has an elastic strain characteristic of a longitudinal elastic modulus of 220 kN / mm ² or more and an elongation of 1.5% or more. It is made of an ultra-high elastic alloy, and at least the distal end side of the wire core wire is thinned, so that a guide wire with low insertion resistance, good torque transmission, and no crushed phenomenon can be obtained. I found.

That is, the medical guidewire according to the present invention is
A medical guide wire having a wire core wire having a distal end side small diameter portion and a proximal end side large diameter portion having a relatively larger outer diameter than the distal end side small diameter portion,
The wire core is made of an ultrahigh elastic alloy having an elastic strain characteristic of a longitudinal elastic modulus of 220 kN / mm ² or more and an elongation of 1.5% or more.

In the present invention, the ultra-high elastic alloy means a material having a longitudinal elastic modulus larger than that of stainless steel (SUS) or iron and having a longitudinal elastic modulus of 220 kN / mm ² or more.

  Preferably, a coil spring is provided along the axial direction on the outer periphery of the distal end side small diameter portion of the wire core. By attaching the coil spring, the elasticity at the distal end side small diameter portion of the wire core can be improved and reinforced. Alternatively, the outer periphery of the wire core may be coated with a biocompatible coating film.

Preferably, the ultra-high elastic alloy constituting the wire core wire is
Cr + Mo; 20-40 mol%, Ni; 20-50 mol%, Co; 25-45 mol%, and Cr-Ni-Mo-Co containing 0.1 to 5 mol% of Mn, Ti, Al, and Fe each A super high elastic alloy,
A composition in which 0.1 to 3 mol% of Nb and 0.01 to 1 mol% of one or more of Ca, Misch metal, Ce, Y, and other rare earth elements are added in combination. Have.

By configuring the wire core with an ultrahigh elastic alloy having such a composition, the wire core has an elastic strain characteristic of a longitudinal elastic modulus of 220 kN / mm ² or more and an elongation of 1.5% or more. , A good torque transmission property, and a guide wire having excellent characteristics with no crushed phenomenon.

  Misch metal is an alloy composed of Ce; about 50 mol%, La; about 25 mol%, and about 25 mol% of other light rare earth elements. Here, it is not preferable that Co is 45 mol% or more because it becomes hard in cold working. The reason why Cr + Mo is preferably in the range of 20 to 40 mol% is that the optimum range for having corrosion resistance is shown in the Co-containing condition, and if this range is exceeded, it becomes hard in cold working and difficult to work. .

  The reason why Ni is preferably 20 to 50 mol% is that it is in an optimum range for maintaining the mechanical strength under the conditions including Co, Cr and Mo. Ti is for increasing the hardness by refining crystal grains and precipitating the compound by heat treatment, and Nb also increases the hardness. The reason why this is limited to 3 mol% or less is that when it is more than that, it becomes too hard during processing and it becomes difficult to process. Further, the simultaneous addition of 0.01 to 1.0 mol% of one or more rare earth elements is for easier workability.

  In the ultrahigh-elasticity alloy of the present invention, Cr: about 15-20 mol%, Mo: about 8-15 mol%, Ni: about 30-35 mol%, Co: about 40-47 mol%, Nb: about 1 More preferably, it is in the range of 3 mol%.

  In order to form a wire core portion which is a long and ultra-high elastic portion of a guide wire, a long and narrow solid rod made of an alloy material having a preferred composition is first cold-worked to a workability of 60% or more at room temperature. The reason why the processing rate at this time is set to 60% or more is that it is a lower limit value indicating an increase in strength and hardness by precipitation hardening, and a high mechanical strength cannot be obtained below this processing rate. Next, the cold-worked material is subjected to precipitation hardening at a temperature of about 400 ° C. to 600 ° C. in a vacuum or in a non-oxidizing atmosphere, and the strength of the material is maintained in the vicinity of Hv 800. This thermo-mechanical treatment imparts uniform fatigue resistance and ultra-high elasticity to the material.

  The elongated core wire of the present invention thus produced has a high elastic modulus and exhibits mechanical properties having a wide strain region. Since the guide wire made of this core wire material is very rigid, it can be advanced without buckling when inserted into a body lumen such as a blood vessel, and at the same time, its elastic extension Due to its size, there is no risk of permanent deformation when the guidewire passes through a very tortuous path such as the coronary artery system.

  Preferably, an outer diameter of the proximal end side large-diameter portion in the wire core wire is 0.30 mm or less. The guide wire of the present invention satisfies the above-described characteristics even if the core wire is thin.

  Preferably, the outer diameter of the small diameter portion of the distal end of the wire core wire decreases gradually or gradually toward the distal end portion of the core wire. By comprising in this way, the flexibility in a distal end part improves.

Hereinafter, the present invention will be described based on embodiments shown in the drawings. put it here,
FIG. 1 is a schematic sectional view of a medical guide wire according to an embodiment of the present invention.
FIG. 2 is a schematic sectional view of a medical guide wire according to another embodiment of the present invention,
FIG. 3 is a view showing an example of use of a medical guide wire;
FIG. 4 is a graph showing the torque transmission characteristics of the medical guide wire according to the embodiment of the present invention.

First Embodiment As shown in FIG. 1, a medical guide wire 2 according to an embodiment of the present invention has a wire core wire 4 and a coil spring 12. The wire core wire 4 has a proximal end side large diameter portion 20, and is continuously formed along the axial direction with respect to the proximal end side large diameter portion 20 and has an outer diameter larger than that of the proximal end side large diameter portion 20. Is composed of the distal end side small-diameter portions 22, 24, and 26 that are gradually reduced. Tapered portions 21, 23, 25 are formed at the joint between the proximal end side large diameter portion 20 and the distal end side small diameter portion 22, and at the joint portions of the distal end side small diameter portions 22, 24, 26, respectively. Yes, the wire core wire 4 has an outer diameter that decreases stepwise toward the distal end side along the axial direction. The coil spring 12 is mounted on the outer periphery of these distal end side small diameter portions 22, 24, 26.

  The wire core wire 4 constituted by the proximal end side large diameter portion 20 and the distal end side small diameter portions 22, 24, and 26 is integrally constituted by a wire having a substantially circular cross section. The wire core wire 4 is formed of an ultra-high elastic alloy at least a part, preferably the entire part thereof.

In the present embodiment, the ultrahigh elastic alloy constituting the wire core wire is
Cr + Mo; 20-40 mol%, Ni; 20-50 mol%, Co; 25-45 mol%, and Cr-Ni-Mo-Co containing 0.1 to 5 mol% of Mn, Ti, Al, and Fe each A super high elastic alloy,
A composition in which 0.1 to 3 mol% of Nb and 0.01 to 1 mol% of one or more of Ca, Misch metal, Ce, Y, and other rare earth elements are added in combination. Alloy.

  The total length of the wire core wire 4 varies depending on the purpose of use and is not particularly limited, but is, for example, about 80 to 350 cm. When used as a guide wire for PTCA, the total length of the wire core wire 4 is about 1500 mm to 2000 mm.

  The outer diameter of the proximal end side large-diameter portion 20 in the wire core wire 4 is not particularly limited, and is generally about 0.10 to 0.90 mm, but in the present embodiment, 0.012 inch (0. 30 mm) or less. Further, the outer diameter of the distal end side small diameter portions 22, 24, 26 is not particularly limited, but is preferably about 1/5 to 1/2 of the outer diameter of the proximal end side large diameter portion 20. Is the diameter.

  A spherical or hemispherical ball portion 10 is joined to the tip of the distal end side small diameter portion 26 of the wire core wire 4. The ball portion 10 is a portion for smoothening the distal end portion of the guide wire 2 and preventing damage to the inner wall of the body cavity as much as possible when the guide wire 2 is inserted into a body cavity such as a blood vessel. It becomes a distal end side stopper. The ball portion 10 is made of, for example, a metal such as tin, silver, gold, or an alloy thereof, and is joined to the tip of the distal end side small diameter portion 26 by means such as welding or brazing. The outer diameter of the ball portion 10 is preferably about 0.5 to 2 times the outer diameter of the proximal end side large diameter portion 20 of the wire core wire 4.

  The distal end 14 of the coil spring 12 is joined to the back surface of the ball portion 10 by means such as welding or brazing. The proximal end 16 of the coil spring 12 may be joined to the outer periphery of the wire core wire 4 by means such as welding or brazing at a tapered portion 21 in the vicinity of the proximal end of the distal end side small diameter portion 22.

  The outer peripheral surface of the portion (proximal end side large diameter portion 20) not covered with the coil spring in the wire core wire 4 may be integrally covered with a biocompatible coating film. Although it does not specifically limit as a biocompatible coating film, For example, normal polymers used for medical uses, such as olefins, such as polyethylene, nitrogen-containing polymers, such as a polyimide and polyamide, a siloxane polymer, and a fluororesin polymer (for example, PTFE) Is used. The coating film is not limited to a polymer, and may be an inorganic coating film such as silicon carbide, carbon such as pyrolite carbon or diamond-like carbon.

  The outer diameter of the coil spring 12 is not particularly limited, but is preferably equal to or less than the outer diameter of the ball portion 10. Although the outer diameter of the wire which comprises the coil spring 12 is not specifically limited, Preferably it is 20-150 micrometers, More preferably, it is the range of 50-100 micrometers.

  The material of the coil spring 12 is not particularly limited, and may be a radiation contrast material or a non-radiation contrast material. Examples of the radiation contrast material include materials having good contrast properties for X-rays, such as platinum, platinum alloys (for example, Pt / Ir = 93/7), gold, gold-copper alloys, tungsten, and tantalum. Further, the radiation non-contrast material is not particularly limited, but stainless steel (for example, SUS316, SUS304) and the like are mainly exemplified. The coil spring 12 may be subjected to a hydrophilic lubrication coating treatment.

  The material of the coil spring 12 is not necessarily the same in the axial direction. For example, the distal end side may be a platinum coil and the proximal end side may be a stainless steel coil.

  In the medical guide wire 2 according to the present embodiment, the operating force of the proximal end side large diameter portion 20 in the guide wire 2 is transmitted well to the distal end portion of the wire 2 and is excellent in pushing characteristics. Further, since the wire core wire 4 is made of an ultra-high elastic alloy, it is possible to reduce the outer diameter while maintaining indentation characteristics and torque transmission. Further, the distal end portion of the wire 2 is thinly tapered in addition to a wide range of elastic strain characteristics, so that even if a relatively large bending deformation occurs when inserted into a blood vessel having a strong bent portion, the plastic deformation region Therefore, it is possible to keep the waist strength more than practical without causing buckling. Furthermore, in this embodiment, since the wire core wire 4 is configured using only an ultra-high elastic metal along the axial direction and does not have a structure for joining different kinds of metals, there is no problem with the strength of the joint portion.

  As a result, as shown in FIG. 3, for example, when the guide wire 2 is inserted from the aorta 42 at the base of the foot to the coronary artery of the heart 40, it has a strong bent portion near the tip of the wire. It is possible to easily follow and insert into blood vessels.

Second Embodiment As shown in FIG. 2, the medical guide wire 2a of the present embodiment does not have the coil spring 12 and has a wire core wire 4 as compared with the medical guide wire 2 of the embodiment shown in FIG. The only difference is that the biocompatible coating film 30 is integrally coated, and common members are denoted by common reference numerals, and a part of description thereof is omitted.

  The biocompatible coating film 30 is not particularly limited, but is an ordinary polymer used for medical purposes, such as olefins such as polyethylene, nitrogen-containing polymers such as polyimide and polyamide, siloxane polymers, and fluororesin polymers (for example, PTFE). Etc. are used. The coating film is not limited to a polymer, and may be an inorganic coating film such as silicon carbide, carbon such as pyrolite carbon or diamond-like carbon.

  The thickness of the biocompatible coating film 30 is thicker at the outer periphery of the distal end small diameter portions 22, 24, and 26 than the outer periphery of the proximal end large diameter portion 20 of the wire 2a, and the outer diameter of the wire 2a is It changes smoothly toward the distal end.

  The medical guide wire 2a according to the present embodiment also has the same effects as the guide wire 2 according to the first embodiment.

  The present invention is not limited to the above-described embodiment, and can be variously modified within the scope of the present invention.

  Hereinafter, although this invention is demonstrated based on a more detailed Example, this invention is not limited to these Examples.

Example 1
A medical guide wire 2 shown in FIG. 1 was produced. First, in order to form the wire core wire 4, the ultrahigh elastic alloy was processed by the following method. Cr; 20.53 mol%, Mo; 8.84 mol%, Ni; 31.24 mol%, Co; 36.42 mol%, Mn; 0.43 mol%, Ti; 0.62 mol%, Al; 0.14 mol%, Fe; 0.7 mol%, Nb; 1.07 mol%, Misch metal; A rod with a diameter of about 10 mm and a composition of 0.01 mol% is stretched to a workability of 97% at room temperature. The wire was processed to a diameter of 0.30 mm. This was straightened and subjected to precipitation hardening in vacuum at a temperature of 500 ° C. At this time, when the characteristics of the obtained ultrahigh elastic alloy were measured, the tensile strength was about 2830 MPa (288.5 kgf / mm ² ), the hardness (Hv) was 804, and the longitudinal elastic modulus was 250 kN / mm ² . The elastic elongation was 1.7%.

  The overall length of the wire core 4 was about 1800 mm, and the outer diameter at the proximal end side large diameter portion 20 was about 0.30 mm (about 0.012 ″). In this embodiment, the distal end side small diameter was The lengths of the portions 22, 24, and 26 were 100 mm, 30 mm, and 40 mm, respectively, and the outer diameters were 0.16 mm, 0.012 mm, and 0.005 mm, respectively.

  The coil spring 12 has a half on the distal end side made of a platinum coil, and the other half on the proximal end side made of a stainless steel coil. The coil had a wire diameter of 60 μm, and a hydrophilic lubrication coating was applied to the coil portion. The length of the coil spring 12 was about 200 mm, and had an outer diameter that was almost the same size as the large diameter portion 20. The wire core wire 4 and the coil spring 12 were fixed to each other by brazing. The outer periphery of the large diameter portion 20 that is an exposed portion of the wire core wire 4 that is not covered with the coil spring 12 was coated with polytetrafluoroethylene (PTFE). The ball part 10 at the tip was made of Sn / Ag alloy and joined by brazing.

  The following experiment was conducted on this guide wire 2.

  Regarding the indentation characteristics of the guide wire, the guide wire was pushed into the pseudo blood vessel in physiological saline 5 times at a speed of 200 mm / min, and the pushing resistance force (N) at each time was measured with a load cell, and these were averaged. Asked. The smaller the average indentation resistance, the better the insertability. In this example, it was 0.25N. It was confirmed that it was lower than Reference Example 1 described later. The results are shown in Table 1. In Table 1, those having lower resistance than Reference Example 1 are shown as ◎, and equivalents are shown as ○.

The pseudo blood vessel was a silicon pseudo blood vessel having an inner diameter of 2.5 mm having a zigzag shape in which three corner portions having an angle of 113 degrees existed every 30 mm in the horizontal direction. The outer curvature at each corner was 12 mm and the inner curvature was 8 mm.

  Moreover, the following experiment was conducted about the torque transmission property of a guide wire. That is, a guide wire is inserted into a pseudo blood vessel bent into a meandering shape by connecting three semicircles having a curvature radius R of 11.5 mm, and the proximal end (hand side) of the guide wire is predetermined by a motor. The distal end rotation angle (twist angle) at the distal end (tip) of the guide wire was examined. The results are shown in FIG. The closer to the theoretical curve shown in FIG. 4, the better the torque transmission and the better the operability. In Table 1, on the basis of Reference Example 2 described later, the one very close to the theoretical curve was marked with ◎, the equivalent was marked with ◯, and the one far from the theoretical curve was marked with Δ.

  Furthermore, the waist strength of the guide wire (GW) was evaluated. When the guide wire is passed through the same pseudo blood vessel used in the experiment on the torque transmission of the guide wire, and then the thrombectomy catheter is inserted along the guide wire, the guide wire is broken. Was judged visually. Note that “lumbar folding” refers to a phenomenon in which a guide wire bends due to the insertion force of a catheter when the catheter is inserted. The results are shown in Table 1. In Table 1, “◎” indicates that no “back folding” occurred, “○” indicates that “back folding” occurred a little, but the degree was weak and the catheter could be inserted without any problem, and “△” “Lumbar break” indicates that it is difficult to use, and “X” indicates that the catheter could not be inserted due to “lump break”.

Example 2
As shown in FIG. 2, a medical guide wire was produced in the same manner as in Example 1 except that the entire wire core wire 4 was covered with the biocompatible coating film 30 without using the coil spring 12.

  FIG. 4 and Table 1 show the results of evaluating the guide wire push-in characteristics, torque transmission, and waist strength in the same manner as in Example 1.

Example 3
A medical guide wire was produced in the same manner as in Example 1 except that the outer diameter of the proximal end side large diameter portion 20 in the wire core wire 4 was changed to 0.337 mm.

  Table 1 shows the results of evaluation of the guide wire pushing characteristics, torque transmission, and waist strength in the same manner as in Example 1.

Reference example 1
A medical guide wire was produced in the same manner as in Example 1 except that the wire core wire 4 was made of SUS304 and the outer diameter of the proximal end side large diameter portion 20 in the wire core wire 4 was 0.337 mm.

  FIG. 4 and Table 1 show the results of evaluating the guide wire pushing characteristics, torque transmission properties, and waist strength in the same manner as in Example 1.

Reference example 2
The proximal end side large diameter portion 20 in the wire core wire 4 is made of SUS304, the distal end side small diameter portions 22, 24, and 26 are made of Ni—Ti alloy, and they are welded, and the proximal end in the wire core wire 4 is welded. A medical guide wire was produced in the same manner as in Example 1 except that the outer diameter of the side large-diameter portion 20 was 0.337 mm.

  FIG. 4 and Table 1 show the results of evaluating the guide wire pushing characteristics, torque transmission properties, and waist strength in the same manner as in Example 1.

Reference example 3
A medical guide wire is formed in the same manner as in Example 1 except that the entire wire core 4 is made of a Ni—Ti alloy and the outer diameter of the proximal end side large diameter portion 20 in the wire core 4 is 0.337 mm. Produced.

  Table 1 shows the results of evaluation of the guide wire pushing characteristics, torque transmission, and waist strength in the same manner as in Example 1.

As shown in Evaluation FIG. 4 and Table 1, the guidewires of Examples 1 and 2 have a smaller outer diameter than that of Example 3 and Reference Examples 1 to 3, but the guide of Reference Example 1 is used. It has indentation characteristics that are equal to or better than those of wires, has excellent torque characteristics, and has little buckling phenomenon. Due to this characteristic, the guide wire of the present invention can be advanced without buckling in the middle even when inserted into a thin and strong blood vessel such as a cerebral blood vessel. It was confirmed that it was possible to transmit well to the end portion.

  As described above, in the guide wire according to the present invention, the operating force of the proximal end portion (proximal end side large diameter portion) of the guide wire is transmitted well to the distal end portion (distal end portion) of the wire. , Excellent indentation characteristics. Moreover, since the wire core is made of an ultra-high elastic alloy, it is possible to reduce the outer diameter while maintaining the indentation characteristics and torque transmission. In addition to the wide range of elastic strain characteristics, the tip of the wire (distal end) is thinly tapered, so even if a relatively large bending deformation occurs when inserted into a blood vessel having a strong bending portion, Without reaching the plastic deformation zone and causing buckling, it is possible to keep the waist strength beyond practical use. Furthermore, in the present invention, the wire core wire is configured by using only an ultra-high elastic metal along the axial direction, and does not have a structure in which different kinds of metals are joined to each other.

FIG. 1 is a schematic sectional view of a medical guide wire according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view of a medical guide wire according to another embodiment of the present invention. FIG. 3 is a view showing an example of use of a medical guide wire. FIG. 4 is a graph showing the torque transmission characteristics of the medical guide wire according to the embodiment of the present invention.

Explanation of symbols

2, 2a ... Medical guide wire 4 ... Wire core wire 10 ... Ball part 12 ... Coil spring 20 ... Proximal end side large diameter part 21, 23, 25 ... Taper part 22, 24, 26 ... Distal end side small diameter part 30 … Biocompatible coating film

Claims (6)

A medical guide wire having a wire core wire having a distal end side small diameter portion and a proximal end side large diameter portion having a relatively larger outer diameter than the distal end side small diameter portion,
A medical guide wire, wherein the wire core wire is made of an ultrahigh elastic alloy having an elastic strain characteristic of a longitudinal elastic modulus of 220 kN / mm ² or more and an elongation of 1.5% or more. The medical guide wire according to claim 1, wherein a coil spring is provided along an axial direction on an outer periphery of the distal end side small-diameter portion of the wire core wire. The medical guide wire according to claim 1, wherein a biocompatible coating film is coated on an outer periphery of the wire core wire. An ultra-high elastic alloy constituting the wire core wire,
Cr + Mo; 20-40 mol%, Ni; 20-50 mol%, Co; 25-45 mol%, and Cr-Ni-Mo-Co containing 0.1 to 5 mol% of Mn, Ti, Al, and Fe each A super high elastic alloy,
A composition in which 0.1 to 3 mol% of Nb and 0.01 to 1 mol% of one or more of Ca, Misch metal, Ce, Y, and other rare earth elements are added in combination. The medical guide wire according to any one of claims 1 to 3. The medical guide wire according to any one of claims 1 to 4, wherein an outer diameter of the proximal end side large-diameter portion of the wire core wire is 0.30 mm or less. The medical guide wire according to any one of claims 1 to 5, wherein an outer diameter of the distal end small-diameter portion of the wire core wire decreases gradually or gradually toward the distal end portion of the core wire.

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