JPH048065B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a core material of a catheter guide wire, which is a medical instrument, and a catheter guide wire.

[Prior Art] In general, a catheter guidewire is introduced into a blood vessel by a Seldinger needle punctured from a blood vessel site, and then the Seldinger needle is removed from the guidewire, a catheter is attached to the rear end of the guidewire, and the pulse of the living body is measured. A medical device used to guide a catheter in advance of a catheter to a target site within a vessel, particularly a blood vessel.

For this reason, the core material of the catheter guidewire is
It is composed of a tip section with a complex shape and a matrix section with a linear shape.
°C), it has elastic properties that allow it to reversibly absorb and release energy as well as reversibly deform and recover its shape when loaded and removed from deformation stress, including twisting, that occurs during introduction and movement into blood vessels. Generally, Ti/Ni alloy is used as the basic material because it is required.

However, Ti・
In catheter guide wires that use a Ni-based alloy material as the core material, as the elongation deformation increases, the load required for deformation increases almost linearly, so it is difficult to introduce the wire into the blood vessel with constant stress. However, it has the drawback of causing physiological pain to both doctors and patients.

Therefore, in the past, Ti/Ni alloys were usually
~40% cold working followed by heat treatment at 400~500℃ produces an improved annealed material,
As a result, in the body (approximately 37 degrees Celsius), even with constant stress, elongation deformation increases (hereinafter referred to as superelastic properties), reversible energy absorption and release, and reversible shape deformation and recovery. A core material for catheter guide wires that could be used for
Publication No. 171570).

[Problems to be Solved by the Invention] However, the rigidity of catheter guide wire core materials using conventional annealed Ti/Ni alloy materials is approximately 1/2 that of core materials using stainless steel wire. However, the problem was that it was difficult to guide the catheter to a desired site within the human body against stress such as intramuscular contraction.

In addition, the tip of the core material is made of a conventional Ti/Ni alloy annealed material to give it superelastic properties, and the matrix part is made of stainless steel wire or the like to give it high rigidity. Even if they are connected as core materials for books, it is not only complicated to manufacture the tip and substrate portions of the core material separately and to connect the tip and substrate portions to each other, but also because the composition components are different from each other. However, there is a need to increase the bonding strength between the annealed material and the stainless steel wire, and there is a drawback that mechanical restraint such as caulking is also required.

On the other hand, since conventional annealed Ti/Ni alloy materials merely have superelastic properties, the tip of the guidewire core material can be shaped into the desired shape depending on the target area. Since it cannot be bent, it is difficult to shape the tip part in a way that is suitable for clinical use, and as a result, the core material of the catheter guide wire with several types of linear shapes must be prepared in advance. .

SUMMARY OF THE INVENTION In view of the above drawbacks, the first technical problem of the present invention is to eliminate the need for the step of separately manufacturing and connecting the distal end of the core material and the substrate of the catheter guidewire, and to make the distal end of the core material of the catheter guide wire have substantially the same composition. Catheter guide wire with a component that has a distal end and a matrix integrally formed, making the distal end flexible at least at body temperature (37°C), while maintaining high rigidity in the matrix. The purpose is to provide a core material for

Further, the second technical problem of the present invention is the above-mentioned first problem.
In addition to the technical challenges of An object of the present invention is to provide a core material for a catheter guide wire that has plasticity that can maintain its deformed shape and has excellent workability.

[Means for Solving the Problems] According to the present invention, there is provided a core material for a catheter guide wire having a distal end portion and a substrate portion integrally configured with each other, the distal end portion and the substrate portion comprising:
The compositional components constituting the Ti/Ni alloy are substantially the same, and the compositional components constituting the Ti/Ni alloy include 50.3 to 52.0 at% Ni, the balance being Ti, and A core material for a catheter guide wire is obtained, which is characterized in that the annealing temperatures of the distal end portion and the substrate portion are different from each other.

Further, according to the present invention, the tip portion is
A core material for a catheter guide wire is obtained, which is made by subjecting a Ti/Ni alloy to a heat treatment of substantially 400 to 500°C, while the substrate portion is made by subjecting it to a heat treatment of less than 400°C.

Further, according to the present invention, the tip portion is
It is made by subjecting a Ti/Ni alloy to a heat treatment of 700°C or higher, and it has substantially superelastic properties at 37°C.
In addition, a core material for a catheter guide wire is obtained, which is characterized by having plasticity against shape deformation at temperatures below 80°C.

Further, according to the present invention, there is obtained a catheter guide wire characterized in that the core material is coated with a synthetic resin.

Here, Ni is 50.3at% of the Ti/Ni alloy.
The above is because the intermediate phase transformation due to aging treatment
It is difficult to obtain less than 50.3at%, and practically 700℃
This is because it becomes difficult to undergo plastic deformation at 37°C due to heat treatment (600 to 1000°C) and cannot escape from the conventional shape memory region. Further, the reason why Ni is set to be less than 52.0 at% is because if it exceeds 52.0 at%, workability deteriorates and there is a practical problem.

[Example] Next, an example of the present invention will be described with reference to the drawings.

-First Example- In this example, an example of the core material of a catheter guide wire is constructed in which the tip part maintains flexibility while the substrate part maintains rigidity under body temperature (37°C). explain.

Preparation process First, in atomic percent, Ni51at%, balance Ti
A Ti/Ni alloy consisting of the following was obtained by high frequency vacuum melting. Note that arc melting, electron beam melting, or powder metallurgy may also be used.

The obtained Ti/Ni alloy was solution-treated at 900-1000℃, then hot-forged and hot-rolled at about 900℃.
Thereafter, it was processed into a wire rod with a size of 0.5 mmφ by cold working (final cold working rate 50%).

Straight Line Treatment Step (Substrate Treatment Step) For thermal straightening, the entire 0.5 mm diameter wire obtained was continuously subjected to a straight line treatment for 5 minutes at 300° C. to achieve straightness.

Superelasticity treatment process (tip treatment process) The obtained wire was cut into 2m dimensions, and approximately
Only the 50 mm length was heat-treated by being kept in a salt bath maintained at about 400°C for 10 minutes, then rapidly cooled, and this was used as the tip.

Superelastic Property Test Using the tip of the wire (No. 2) and the remainder as the substrate (No. 1), the stress-strain curves of each portion at body temperature (37° C.) were measured. As a comparative example, 18-8 stainless steel wire (No. 4) was also measured.
The results are shown in FIG.

As a result, for the substrate part (No. 1) sample, 100 kg
The stress value exceeds f/mm ² , which is higher than that of the 18-8 stainless steel wire (No. 4). On the other hand, the tip (No. 2) showed a clear descending shape (stress value 60 Kgf/mm ² ) at 1% strain, indicating that it had extremely excellent superelastic properties.

This has made it possible to provide different material properties, such as supple superelastic properties and higher rigidity than 18-8 stainless steel wire, in a single wire made of the same composition.

Note that the heat treatment at 300°C in the straightening process mentioned above was carried out solely for the purpose of heat straightening, so if linearity is achieved in the cold-worked finish, heat treatment of the substrate is not necessary. Of course.

In addition, 400℃ in the superelastic treatment process of the tip
The heat treatment may be performed within the range of 400 to 500°C.
Note that as the heat treatment temperature increases, it is necessary to shorten the treatment time.

-Second Example- Similarly to the first example, the following superelasticity treatment process (tip treatment process) was performed using the wire that had undergone the preparation process and the straight line treatment process (substrate treatment process).

First, the obtained wire was cut into 2m lengths, and only a length of about 50mm from the end face was kept in a salt bath maintained at about 700°C for 2 minutes, then rapidly cooled, and this was called the tip (No. 3). did.

Next, the stress-strain curve of the tip (No. 3) of the wire at body temperature (37° C.) was measured. The results are shown in FIG.

As a result, the sample at the tip (No. 3) treated at 700°C showed only a slight amount of plastic deformation at 1% strain, which was actually smaller than the amount of plastic deformation (residual strain) of the 18-8 stainless steel wire. Similar to the tip portion (No. 2) of the first example, a drop in shape from a strain of about 1% is also observed, which indicates that it has superelastic properties.

On the other hand, in a strongly deformed state where a strain of 3% or more is applied, it was observed that the sample at the tip (No. 3) treated at 700°C retained a large amount of plastic deformation.

Therefore, by using the sample of the tip part (No. 3) treated at 700°C, which has excellent plasticity, as the tip part of the core material of the catheter guide wire, it is possible to deform it into any shape suitable for clinical use. It turns out that you can do it.

-Third Example- In order to taper the tip of the core material of a catheter guidewire obtained by the same method as in the second example, the tip was thinned by chemical treatment (fluoric acid), and then the entire length was coated with synthetic resin.

As shown in FIG. 3, the synthetic resin coating 4 has a substantially uniform outer diameter including the tip. especially,
This synthetic resin coating 4 has a substantially uniform outer diameter. As the synthetic resin coating 4, polyethylene,
Polyvinyl chloride, polyester, polypropylene, polyamide, polyurethane, polystyrene,
Fluororesin, silicone rubber, or their respective elastomers and composite materials are preferably used. Preferably, the synthetic resin coating 4 is flexible to the extent that it does not interfere with the curvature of the inner core 2, and the outer surface is smooth without any irregularities. In addition, the synthetic resin coating 4 may contain an anticoagulant such as heparin or urokinase, silicone rubber, or a block copolymer of urethane and silicone (registered trademark).
Anti-thrombotic materials such as hydroxyethyl methacrylate-styrene copolymers, etc. may also be coated. Furthermore, the friction properties of the guide wire 1 can be reduced by forming the synthetic resin coating 4 from a resin having a low friction surface such as fluorine resin, and by applying a lubricant such as silicone oil to the outer surface of the synthetic resin coating 4. You may let them. Furthermore, in the synthetic resin forming the synthetic resin coating 4, Ba, W, Bi, Pb
X in fine powder form made of simple metals or compounds such as
It is preferable to mix a radiographic contrast substance, and by doing so, it becomes easy to confirm the entire position of the guide wire 1 being introduced into the blood vessel. As described above, the synthetic resin coating 4 has a substantially uniform outer diameter. "Substantially uniform" does not necessarily mean completely uniform, but may have a slightly narrower diameter at the tip. In this way, by making it almost uniform up to the tip,
Damage that the tip of the guide wire may cause to the inner wall of the blood vessel can be reduced.

The outer diameter of the synthetic resin coating is 0.25 to 1.04 mm, preferably 0.30 to 0.64 mm, and the thickness of the core material 2 on the main body portion 2a is 0.03 to 0.30 mm, preferably 0.05 to 0.20 mm.

Further, it is preferable that the synthetic resin coating 4 is tightly adhered to the inner core 2 by a synthetic resin, and is also fixed to the distal end portion and the substrate portion of the inner core 2. Alternatively, the synthetic resin coating 4 may be formed of a hollow tube and fixed to the inner core 2 by adhesion or melt molding at the tip and substrate portion of the inner core 2 or at a suitable portion of the inner core. The tip of the guide wire 1 (the tip of the synthetic resin coating 4) has a curved surface such as a hemispherical shape as shown in FIG. 3 in order to prevent damage to the blood vessel wall and improve the operability of the guide wire 1. It is preferable that

Furthermore, it is preferable that a lubricating substance is fixed to the surface of the synthetic resin coating 4. A lubricating substance refers to a substance that has lubricating properties when wet. Specifically, there are water-soluble polymer substances or derivatives thereof.

That is, the core material 2 of the guide wire in this example has a total length of 1800 mm, a tip diameter of 0.06 mm, a rear end diameter of 0.25 mm, and a tapered diameter of 120 mm from the tip toward the tip. created something.

Furthermore, the entire outer surface of the core material is coated with polyurethane containing 45% by weight of fine tungsten powder (particle size approximately 3 to 4 μm) so that the overall outer diameter is almost uniform.
A synthetic resin film was formed. Then, a solution of 5.0% by weight of maleic anhydride ethyl ester copolymer dissolved in tetrahydrofuran was applied to the surface of the synthetic resin coating formed from the above polyurethane, and the maleic anhydride ethyl ester copolymer was dissolved in tetrahydrofuran. was fixed to form a lubricious surface.

This guidewire has an overall length of approximately 1800mm
mm, the overall diameter is 0.36 mm.

[Effect of the invention] As can be seen from the above explanation, according to the present invention,
Since the distal end of the catheter guide wire core material and the matrix were constructed using substantially the same compositional components constituting the Ti/Ni alloy, the distal end and the matrix were manufactured separately and connected. This eliminates the need for the process of
The tip part and the matrix part are integrally formed, and only the tip part maintains flexibility at least at body temperature (37℃), while the matrix part maintains the rigidity of the Ti/Ni alloy itself. A core material can be provided.

Further, according to the present invention, since only the tip portion is annealed at a temperature of 700°C or higher, the tip portion of the core material of the guidewire can be bent into a desired shape depending on the target area, and is clinically applicable. hot water etc. used in
It is possible to provide a core material for a catheter guide wire and a catheter guide wire that have plasticity that can maintain its deformed shape even in an environment of 80° C. and have excellent workability.

[Brief explanation of drawings]

Figure 1 shows the stress measured at body temperature (37°C) under tensile stress in a Ti/Ni alloy containing 51 at% Ni.
FIG. 2 is a cross-sectional view of a catheter guide wire coated with a synthetic resin according to an embodiment of the present invention. No. 1...Substrate part related to the first embodiment of the present invention,
No. 2...300℃X10 related to the first embodiment of the present invention
Tip part subjected to heat treatment for 2 minutes, No. 3... Tip part subjected to heat treatment at 700°C for 2 minutes related to the first embodiment of the present invention, 1... Catheter guide wire,
2... Inner core, 2a... Core main body, 4... Synthetic resin coating.

Claims (1)

[Scope of Claims] 1. A core material of a catheter guide wire having a distal end portion and a substrate portion integrally formed with each other, wherein the distal end portion and the substrate portion are substantially made of a Ti/Ni alloy. have the same compositional components, and the compositional components constituting the Ti/Ni alloy include 50.3 to 52.0at% Ni, the balance being Ti, and the annealing temperature of the Ti/Ni alloy is the same as that of the Ti/Ni alloy. A core material for a catheter guide wire, which is characterized by being different between a distal end portion and a matrix portion. 2. The core material of the catheter guide wire according to claim 1, wherein the tip portion is substantially attached to the Ti/Ni alloy.
1. A core material for a catheter guide wire, characterized in that the substrate portion is heat-treated at a temperature of 400 to 500°C, and the substrate portion is heat-treated at a temperature of less than 400°C. 3. In the core material of the catheter guide wire according to claim 1, the tip portion is substantially attached to the Ti/Ni alloy.
It is heat-treated at 700℃ or higher, and has a temperature of 37℃.
A core material for a catheter guide wire, characterized by having superelastic properties at a temperature of 80° C. and plasticity against shape deformation at a temperature of 80° C. or less. 4. A catheter guide wire characterized in that the core material according to any one of claims 1 to 3 is coated with a synthetic resin.