JPH01170475A - Guide wire for catheter - Google Patents

Abstract

PURPOSE:To easily insert the title guide wire in a Seldinger needle, by forming the leading end part of a core metal from an ultra-elastic metal while forming the leading end part of a coil spring from a shape memory alloy having martensite inverse transformation start temp. of a specific value to transform the same into a curved shape at temp. higher than said temp. by a required value. CONSTITUTION:A leading end part core metal 3 is formed from an ultra-elastic alloy. As the ultra-elastic alloy, there is an alloy having a wide elastic region showing no plastic deformation even when tensile strain is about 8% and, for example, an Ni-Ti alloy, a Cu-Al-Ni alloy or the like are pref. A coil spring 4 covering the leading end part core metal 3 is formed from a shape memory alloy having martensite inverse transformation start temp. of 0-40 deg.C and is transformed into a curved state at temp. higher than said temp. by a lequired value so as to change the whole of the leading end part of a guide wire 1 to a curved shape. By this constitution, at the insertion time of the guide wire, the force due to the operation of a base end part (on this side) can be certainly transmitted to the leading end part to make the wire guide easy to insert.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to a target site in a blood vessel, gastrointestinal tract, or trachea.
This invention relates to a guide wire for catheters for use in catheters for treatment or testing.

BACKGROUND OF THE INVENTION Conventionally, guide wires for catheters include guide wires using a coil spring made of stainless steel wire or piano wire, and guide wires using a plastic monofilament. There are two types of guide wires: one with a straight tip and one with a J-shaped tip.

After a guide wire is inserted into a blood vessel along with a catheter, it is used to guide the catheter to the target blood vessel site.
The tip of the guide wire is made to protrude a predetermined length from the tip of the catheter, and the tip of the guide wire is pushed ahead of the catheter.

Therefore, the tip of the guide wire is required to be flexible so that it can be inserted into meandering blood vessels and complicated blood vessel branches without damaging the blood vessel wall.

However, the above-mentioned guide wire does not have sufficient flexibility or restorability because its distal end portion is made of a general metal material or plastic.

Therefore, the present applicant has proposed a guide wire that solves the above-mentioned problems (Japanese Patent Laid-Open Nos. 60-63065 and 60-63066).

The above-mentioned guide wire has sufficient flexibility and restorability, but a straight guide wire can be used satisfactorily for patients with less meandering of the aorta, and generally younger patients. In patients with meandering arteries or patients with a large amount of cholesterol or fat deposited in the arterial blood vessels, it may be difficult to insert a guide wire with a straight tip as described above, so a guide wire with a curved tip may be used. wire was used.

However, the guide wire having a curved tip as described above has a problem in that it is difficult to insert it into the Seldinger needle that is punctured to insert the catheter into the femoral artery.

[Problems to be solved by the invention] The above-mentioned JP-A-60-63065, JP-A-60-6
The guide wire disclosed in Japanese Patent No. 3066 has sufficient flexibility and resilience, but the guide wire with a curved tip does not allow insertion into the Seldinger needle that is punctured to insert the catheter into the femoral artery. The problem was that it was difficult.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a catheter guide wire that has high flexibility and resilience and can be easily inserted into a Seldinger needle even if the guide wire has a curved tip. .

[Means for Solving the Problems] What achieves the above object is a guide wire for a catheter having a core bar and a coil spring encasing at least a distal end portion of the core bar. The tip is
The coil spring is made of a superelastic metal, and the tip of the coil spring is made of a shape memory alloy whose martensitic reverse transformation start temperature is 0°C to 40°C, and which bends into a curved shape at a predetermined temperature higher than the temperature. This is a catheter guide wire that is formed to transform into a catheter.

Preferably, the tip of the core metal is fixed to the tip of the coil spring.

Preferably, the core metal has a main body core metal that continues to the tip end, and the tip end portion preferably has a smaller diameter than the main body core metal. Further, the core metal includes, for example, a tip core metal forming the tip end portion, and a main body core metal connected to a base end of the tip core metal. Further, it is preferable that the main body core metal is made of a material with high rigidity. Further, the coil spring has, for example, a hemispherical tip, encloses the tip core, and has a base end fixed near the connection between the tip core and the main body core. It is. Preferably, the material having high rigidity is stainless steel. Preferably, the stainless steel is a high tensile strength stainless steel for springs. Further, the coil spring may, for example, cover the entire core metal. Further, it is preferable that the martensitic reverse transformation start temperature of the shape memory alloy is 26°C to 36°C. The superelastic alloy is a Ni-Ti alloy, a Cu-Zn-At alloy, or a C
Preferably, it is one of u-Al-Ni alloys.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The catheter guide wire of the present invention will be explained using embodiments shown in the drawings.

The catheter guide wire 1 of the present invention is a guide wire having a core metal and a coil spring encasing at least the distal end portion of the core metal, the distal end portion of the core metal being made of a superelastic metal, The tip of the coil spring 4 has a martensite reverse transformation starting temperature of 0°C to 40°C.
It is made of a shape-memory alloy having a temperature of 0.degree. C., and is formed to transform into a curved shape at a temperature higher than the temperature.

Therefore, an explanation will be given using the embodiment shown in FIG.

A catheter guide wire 1 shown in FIG. 1 consists of a core metal and a coil spring 4. The catheter guide wire 1 shown in FIG.

Specifically, the core metal is formed by a tip core metal 3 made of superelastic metal and a main body core metal 2 connected to the rear end of the tip core metal 3, and a coil spring 4.
The base end portion is fixed near the connecting portion between the tip core metal 3 and the main body core metal 2, and the coil spring 4 is formed of a shape memory alloy.

The main body core bar 2 forms the main body of the guide wire 1, and preferably has a function of reliably transmitting an operation at the proximal end (hand at the time of use) of the guide wire l to its distal end. , Therefore, it is preferable to be formed of a material with high rigidity. As for the rigidity, it is preferable that the bending rigidity is 15 kgxm" or more, preferably 18 to 9xz2 or more.

Stainless steel or the like is suitable as the material for the main body core metal 2, and high tensile strength stainless steel for springs is particularly suitable. By forming the guide wire from a material with high bending rigidity, when inserting the guide wire, when manipulating the tip to travel in the desired direction within a lumen such as a blood vessel, and when pushing the tip, In addition, the force generated when rotating the guide wire at the proximal end (proximal end) can be reliably transmitted to the distal end, making insertion easier.

The main body core bar 2 has a diameter of 0.2 to 1.8 cm.
, preferably 03 to 1.6. iu, length 30xx~4
000 mm1 is preferably 50+u+ to 3500 mm.

The tip core bar 3 forming the tip of the core bar forms a guiding part for advancing the guide wire through a meandering blood vessel or a narrow blood vessel, and must be flexible. be.

Therefore, in this embodiment, the tip core bar 3 that forms the tip is made of a superelastic alloy, and the superelastic alloy is an alloy that has a wide elastic region that does not deform plastically even under a tensile strain of about 8%. For example, superelastic materials such as Ni-Ti alloy, Cu-A1-Ni alloy, Cu-Zn-Al alloy, etc. are suitable.

The tip core metal 3 has a wire diameter of 0.05 shoulder'R ~ 16 m2
, the length is 10 cm to 500 m, preferably 20 cm to 500 m.
It is 300nth order. It is preferable that the tip end core bar 3 is more flexible on the tip side, and in particular, it is preferable that it gradually becomes more flexible toward the tip. Therefore, in the embodiment shown in FIG. No. 3 has a diameter that gradually becomes smaller, and by changing the diameter, the flexibility may be changed depending on the application, or it may be made gradually softer toward the tip by heat treatment.

The coil spring 4 enclosing the tip core metal 3 is made of a shape memory alloy whose martensitic reverse transformation start temperature is 0°C to 40°C, and is further bent into a curved shape at a temperature higher than the above temperature. As shown in FIG. 2, the guide wire l
The entire tip is curved. Shape memory alloys include Ni-Ti alloy, Au-Cd alloy, Cu-AI-Ni alloy, Cu-Au-Z
n-based alloy, Cu-Zn, -X (X is Si.

Sn, A1. Ca) based alloy, and Ni-A
The shape memory alloy is formed from a shape memory alloy whose martensitic reverse transformation start temperature (the temperature at which the martensite phase begins to disappear and becomes the parent phase of the austenite phase) is 0°C to 40°C. Ru. Further, the coil spring 4 is formed into a curved shape, for example, a J shape, at a high temperature, and remembers the curved shape. Then, by stretching it in a straight line in a cooled state, it becomes a straight line as shown in Figure 1, and by inserting it into a blood vessel and heating it, it becomes the memorized curved shape. 2, and the entire tip of the guide wire 1 is changed into a curved shape as shown in FIG.

Shape memory alloys with a martensite reverse transformation initiation temperature of 40°C or lower are used because blood cell components and tissue cells are likely to be destroyed at approximately 42°C, so they cannot be introduced into blood vessels. The temperature limit at which the tip of the guidewire is heated (e.g., by high-frequency heating, heat transfer by heating the rear end of the guidewire) must be 42°C;
Furthermore, in order for the coil spring 4 to return to its curved shape, it is necessary to at least 2°C below the martensite reverse transformation start temperature.
This is because there is a need to increase it.

In other words, if the martensite reverse transformation start temperature is 40°C or less, the martensite reverse transformation start temperature is 2°C lower than the martensite reverse transformation start temperature.
If heated to a high temperature, the martensite phase in the structure will disappear and the austenite phase will appear at a rate of several tens of percent, almost returning to the memorized curved shape. It was set as ℃. Further, the reason why the temperature is set at 0°C or higher is that it is usually difficult to cool the temperature to 0°C or lower. When the martensite reverse transformation starting temperature is between 0°C and 25°C, the room temperature in the operating room is usually 25°C.
Since the temperature is adjusted to approximately 0.9°C, it returns to its memorized curved shape at room temperature.

Therefore, since it has a curved shape before being inserted into the blood vessel, that part (coil spring 4) is immersed in ice water or alcohol cooled with ice water to cool it and straighten the tip before use. . The martensite reverse transformation starting temperature is preferably 26°C to 36°C, and if it is 26°C or higher, there is little possibility that the martensite will return to its curved shape due to the room temperature in the operating room, and it will not be used. There is no need for pre-cooling or straightening, and 3
If it is below 6 degrees Celsius, the temperature of the blood is about 38 degrees Celsius, so by inserting it into the blood vessel, it will be warmed by the blood and return to its naturally memorized curved shape, so other means can be used. This is preferable since there is no need to heat it from the outside.

The tip of the coil spring 4 has a hemispherical tip 5.
It becomes. A hemispherical tip means a substantially curved tip, and includes shapes such as a bell shape and a bullet shape. As the coil spring 4,
The length is 10ix ~ 500R, preferably 2 (11 pieces ~
:a00m*S, the outer diameter of the coil spring 4 is:
Diameter 0.2-1.8 Ri, preferably 0.3-1. S
im The coil spring 4 covers the tip core metal 3 and is fixed to the tip of the tip core metal 3, and the base end is connected to the tip i portion core metal 3 and the main body core metal 2. It is fixed with wax 10 or the like near the connection part.

The bending stress of the tip core metal 3 is smaller than the return stress when the shape memory alloy forming the coil spring 4 transforms into a curved shape (the return stress during reverse transformation from the martensitic phase to the parent phase). As in, it is formed. Therefore, the coil spring 4 is not affected by the bending stress of the tip core metal 3 and can be transformed into the memorized curved state by being heated, and the guide wire l
It is possible to transform the entire tip of the tip into a curved state as shown in FIG.

Further, since the coil spring 4 made of a shape memory alloy has the tip core bar 3 made of a superelastic metal, it is possible to prevent the coil spring 4 from overextending, and furthermore, in the normal state, It is possible to reinforce the shape memory alloy, which is soft due to its martensitic phase and easily deforms plastically with a small amount of force, making it easy to maintain the straightened state when inserted into the gilator. becomes.

In addition, since a superelastic metal is used for the tip core bar 3, its bending stress can be reduced, and the coil spring 4 has a lower memory than conventional stainless steel. It becomes possible to reliably express the curved state that exists.

Further, the coil spring 4 is not limited to being formed entirely of a shape memory alloy, but it is sufficient that at least the tip portion thereof is formed of a shape memory alloy. For example, as shown in FIG. By the tip coil spring 41 and the base coil spring 42,
Alternatively, the distal end coil spring 41 may be formed of a shape memory alloy, and the proximal end coil spring 42 may be formed of stainless steel or the like.

In addition. In this case, in order to ensure the connection between the distal end coil spring 41 and the proximal end coil spring 42, the inner surface near the connection part and the outer surface of the distal end core bar 3 are bonded with a wax 11.
It is preferable to fix it using, for example.

The tip core bar 3 and the main body core bar 2 can be connected by fitting the proximal end of the tip core bar 3 onto the tip of the main body core bar 2, or by brazing the two together. A known method or a combination of both can be used. In particular, as shown in FIG. 1, a hole having an inner diameter equal to or slightly larger than the diameter of the proximal end of the tip core metal 3 is provided at the tip of the main body core metal 2, and the tip core metal 3 is inserted into the hole. It is preferable to insert the proximal end of the connector and fix the vicinity of the connecting portion between the two with wax lO. By doing this, the two can be firmly connected.

Furthermore, a lubricity agent 12 is provided on the outer surface of the main body core bar 2 to reduce frictional resistance with the inner surface of a cylindrical body such as a catheter.
The thickness of the coating is preferably from several microns to several hundred microns.

As the lubricity imparting agent, water-soluble polymeric substances or derivatives thereof are preferable, such as poly(2-hydroxyethyl methacrylate), polyhydroxyethyl acrylate, cellulose-based polymeric substances (e.g., hydroxypropyl cellulose, hydroxyethyl cellulose), Maleic anhydride-based polymer substances (e.g., methyl vinyl ether maleic anhydride copolymer), acrylamide-based polymer substances (e.g., polyacrylamide), polyethylene oxide-based polymer substances (e.g., polyethylene oxide, polyethylene glycol), polyvinyl alcohol ,
Polyacrylic acid-based polymer substances (e.g., sodium polyacrylate), phthalic acid-based polymer substances (e.g., polyhydroxyethyl phthalate), water-soluble polyester (
For example, polydimethylolpropionate), ketone aldehyde resins (eg, methyl isopropyl ketone formaldehyde), polyvinylpyrrolidone, polyethyleneimine, polystyrene sulfonate, water-soluble nylon, and the like may be used. Furthermore, it is preferable to prevent the lubricity imparting agent from easily peeling off or flowing out. For example, a coating of a chemical compound having a reactive functional group is formed on the outer surface of the main body core bar 2, and a water-soluble polymeric material is formed on the outer surface of the main body core bar 2. It is preferred that the water-soluble polymer substance or its derivative be coated on the coating of the compound by ionic or covalent bonding of the compound or its derivative with the reactive functional group of the compound. As the water-soluble polymeric substance or its derivative, the above-mentioned substances can be suitably used. The reactive functional group is preferably an isocyanate group, an amino group, an aldehyde group, an epoxy group, etc. Therefore, as a compound having a reactive functional group and coating forming property, polyurethane, polyamide, etc. are suitable. It is. Furthermore, in order to increase the number of reactive functional groups, it is preferable to mix a substance having a reactive functional group into the above compound. Such substances include ethylene diisocyanate, hexamethylene diisocyanate,
Isocyanates such as xylene diisocyanate, toluene diisonanate, diphenylmethane diisocyanate, adducts or prepolymers of these isocyanates and polyols, polyamines (e.g., low molecular polyamines, ethylene diamine, trimethylene diamine, etc., and high molecular polyamines), gel tar aldehyde, etc. Can be mentioned.

In addition, as a coating method, a substance having a reactive functional group [
For example, a solution of polyurethane (tetrahydrofuran solution)] and a substance having a reactive functional group [e.g., a solution of 4.4 diphenylmethane diisocyanate (methyl ethyl ketone solution) ) and drying, and then contacting with a water-soluble polymer [for example, a solution of methyl vinyl ether maleic anhydride copolymer (methyl ethyl ketone solution)] and drying. By doing so, lubricity can be imparted to the surface of the guide wire, and furthermore, the lubricity can be maintained for a long time.

Next, an embodiment of the catheter guide wire of the present invention shown in FIG. 4 will be described.

The catheter guide wire 1 shown in FIG. 4 includes a core metal 2 and a coil spring 4 made of a shape memory alloy that covers the entire core metal 2. The catheter guide wire 1 shown in FIG.

In this embodiment, the core metal 2 is made of a superelastic alloy, and the superelastic alloy is an alloy that has a wide elastic range that does not undergo plastic deformation even when the tensile strain is about 8%. Alloy, Cu-Al-Ni alloy, C
Superelastic materials such as u-Zn-At alloys are preferred.

As the core metal 2, the length is 100J+x ~ 4000JIJ
! , preferably 150 scraps 1 to 3500 zm, and the reduced diameter tip 31 preferably has a wire diameter of 0.1xx to 0.4ix.

The coil spring 4 is formed of a shape memory alloy whose martensite reverse transformation start temperature is 0° C. to 40° C., and the tip portion 31, which is further reduced in diameter, has a temperature higher than the martensite reverse transformation start temperature. It is formed so that it transforms into a curved shape at high temperatures. As the shape memory alloy, those explained in the embodiment of FIG. 1 can be suitably used. The martensite reverse transformation starting temperature is preferably 26°C to 36°C.

The coil spring 4 has a length of 100ix to 40
00ax, preferably 150mm to 3500mx, the outer diameter of the coil spring 4 is 0.2 to l,
8mm.

Preferably it is 0.3 to 1.6ii. In the coil spring 4, at least the tip portion of the portion enclosing the tip portion 31 of the core metal is formed of a shape memory alloy, and the portion enclosing the main body portion 32 of the core metal is made of a shape memory alloy. It does not have to be a shape memory alloy, and may be made of, for example, stainless steel.

Further, it is preferable that the core bar 2 is gradually flexible toward the tip, and may have a diameter that gradually decreases toward the tip.By changing the diameter, the flexibility can be changed according to the application. Alternatively, it may be made gradually softer toward the tip by heat treatment.

The bending stress of the tip 31 of the core metal is the return stress when the shape memory alloy that forms the tip of the coil spring 4 transforms into a curved shape (the return stress when the reverse transformation from the martensitic phase to the matrix phase occurs). ) is formed to be smaller. Therefore, the fill spring 4 can transform into the memorized curved state by being heated without being affected by the bending stress of the tip 31 of the core metal.
It is possible to transform the entire tip of the guide wire 1 into a curved state. Furthermore, since the coil spring 4 made of a shape memory alloy has a tip 31 of a core metal made of a superelastic metal, it is possible to prevent the coil spring 4 from overextending, and furthermore, it is possible to prevent the coil spring 4 from being overextended. Because it is a martensitic phase, it is soft and can easily be plastically deformed by a small amount of force, so it is possible to reinforce the shape memory alloy, which allows it to maintain its straightened state when inserted into the dilator. It becomes easier. In addition, since a superelastic metal is used for the tip 31 of the core metal, the bending stress can be reduced, and the coil spring 4 has less memory than conventionally used stainless steel. This makes it possible to reliably create a curved state.

The main body part 32 forms the main body part of the guide wire I, and is formed integrally with the distal end part 21.

The continuous portion between the tip portion 31 and the main body portion 32 has a gently tapered shape. The main body part 32 has a wire diameter of 0.2 to 1, F3xm, preferably 0.3 to 1.7I.
I, length 30 shoulders 11-400011. Preferably 50
11z~350011. The main body part 32 has a distal end part 3
1, but may be formed as a separate member as in the embodiment shown in FIG. High tensile strength stainless steel for springs is particularly suitable. By using such a highly rigid material, the tip of the guide wire 1 can be easily moved in the desired direction within a lumen such as a blood vessel, when pushing the tip, or when rotating the tip. The force generated by the operation at the proximal end (proximal end) of the guidewire can be reliably transmitted to the distal end, making insertion easier.

Further, it is preferable to coat the outer surface of the coil spring 4 on which the main body portion 32 is located with a lubricity agent to reduce the frictional resistance with the inner surface of a cylindrical body such as a catheter. It is preferably about microns to several hundred microns. As the lubricity imparting agent, those mentioned above can be suitably used.

[Function] Next, the function of the catheter guide wire of the present invention will be explained using the embodiment shown in FIG.

The guide wire 1 of the present invention includes an angiography catheter,
It is used to guide a catheter such as a vasodilator catheter when inserting it into a target part of a blood vessel.When inserting the guide wire 1, first secure a blood vessel in the human body by the Seldingo method, etc. The catheter guide wire I of the present invention is placed in a blood vessel, and the catheter is inserted into the blood vessel along it.

If the tip of the guidewire is curved before insertion, cool it with ice water, etc.
After stretching it into a straight line, insert it. During this insertion, the catheter guide wire l
Insert into the blood vessel with the tube protruding several cm.

The tip of this guide wire restores its curved shape as shown in Figure 2 by heating, so even if it is inside a meandering blood vessel or a blood vessel with neutral fat, cholesterol, etc. , the tip does not come into contact with the blood vessel wall and can be easily inserted, and since the tip has a coil spring 4 made of superelastic metal, it is sufficiently flexible and can be easily inserted into tortuous blood vessels. It can be easily inserted into a blood vessel with a pongee diameter. After the tip of the catheter has been guided to the vicinity of the target site, the guide wire 1 is removed, and if the catheter is an angiography catheter, a vascular contrast agent is injected from the rear end, X-ray contrast is performed, and the catheter is Remove it, apply pressure, and complete the 7th procedure.

[Effects of the Invention] The catheter guide wire of the present invention includes a core metal and a coil spring that envelops at least a distal end portion of the core metal, the distal end portion of the core metal comprising: The coil spring is made of a superelastic metal, and the tip of the coil spring is made of a shape memory alloy whose martensitic reverse transformation initiation temperature is O'C to 40°C, and which transforms into a curved shape at a temperature higher than the above temperature. In particular, the tip of the core metal transforms into a curved shape when heated, so when inserted into a blood vessel, it must be in a straight shape. There is no need to use a guide inserter, which is required when inserting a conventional guide wire with a curved tip, and it can be easily inserted into a blood vessel. Furthermore, since the tip of the core bar is made of superelastic metal, it is sufficiently flexible and can be easily inserted into tortuous blood vessels and narrow blood vessels, and furthermore, it does not cause damage to the blood vessel wall. There is no fear. By having a core made of superelastic metal inside the coil spring made of shape memory alloy,
This prevents the coil spring from overextending, and in addition, it is soft and soft due to its martensitic phase under normal conditions.
The shape memory alloy, which easily deforms plastically with a small amount of force, can be reinforced, making it easier to maintain a straightened state when inserted into the gillator, making initial insertion into the blood vessel easier. It becomes easier. Furthermore, since a superelastic metal is used for the tip of the core metal, the bending stress can be reduced, and the coil spring has a lower memory than conventional stainless steel. It becomes possible to reliably develop a curved state.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing one embodiment of the catheter guide wire of the present invention, FIG. 2 is a view showing the catheter guide wire of FIG. 1 in a state where the distal end portion is curved, and FIG. 4 is a sectional view showing another embodiment of the catheter guide wire of the present invention. FIG. 4 is a sectional view showing another embodiment of the catheter guide wire of the present invention. l... Catheter guide wire

Claims (11)

[Claims] (1) A catheter guide wire having a core metal and a coil spring encasing at least a distal end portion of the core metal, the distal end portion of the core metal being formed of a superelastic metal, and the coil spring enclosing at least a distal end portion of the core metal The tip of the spring is made of a shape memory alloy with a martensitic reverse transformation starting temperature of 0°C to 40°C, and is formed to transform into a curved shape at a temperature higher than the above temperature. Guidewire for catheters. (2) The catheter guide wire according to claim 1, wherein the tip of the core bar is fixed to the tip of the coil spring. (3) The cored metal has a main body cored metal that continues to the tip, and the tip has a smaller diameter than the main body cored metal. Guidewire for the catheter described. (4) The core metal comprises a tip core metal forming the tip end and a main body core metal connected to the base end of the tip core metal. A catheter guide wire described in . (5) The catheter guide wire according to claim 3, wherein the main body core metal is made of a material with high rigidity. (6) the coil spring has a hemispherical tip;
The guide for a catheter according to claim 4 or 5, which encloses the distal end cored metal and has a proximal end portion fixed near a connecting portion between the distal end cored metal and the main body cored metal. wire. (7) The catheter guide wire according to any one of claims 4 to 6, wherein the material having high rigidity is stainless steel. (8) The guide wire for a catheter according to claim 7, wherein the stainless steel is a high-tensile stainless steel for springs. (9) The catheter guide wire according to claim 1 or 2, wherein the coil spring covers the entire core metal. (10) Claim 1, wherein the martensitic reverse transformation initiation temperature of the shape memory alloy is 26°C to 36°C.
The guide wire for a catheter according to any one of Items 1 to 9. (11) Superelastic alloys include Ni-Ti alloy, Cu-Zn
- The catheter guide wire according to any one of claims 1 to 10, which is made of either an Al-based alloy or a Cu-Al-Ni-based alloy.