JPH02289267A - Core for catheter guide wire and catheter guide wire - Google Patents

Abstract

PURPOSE:To maintain ductility of a tip part at a body heat and to maintain rigidity of a substrate part at a high value by a method wherein the tip part and the substrate part have substantially the same composition component as that by which a Ti.Ni series alloy is formed, and the annealing temperature of the tip part is different from that of the substrate part. CONSTITUTION:A tip part and a substrate part have substantially the same composition component as that by which a Ti-Ni series alloy is formed. The composition component contains 50.3-52.0at% in atomic percent and balancing Ti, and the annealing temperature of the tip part is different from that of the substrate part. Namely, in the tip part, heat treatment of 400-500 deg.C is substantially applied on the Ti.Ni series alloy, and in the substrate part, heat treatment of 400 deg.C or less is applied. This constitution provides the core of a catheter in which the tip part maintains ductility at a body heat (37 deg.C) or less and meanwhile the substrate part maintains rigidity.

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 guide wire.

! , 12 It is composed of a tip section with a rough shape and a matrix section with a linear shape, and also has a deformation stress load including twisting that occurs during introduction and movement into blood vessels at biological temperature (approximately 37 degrees Celsius).・Reversible energy absorption associated with removal・
Generally, Ti-N is required to have elastic properties that enable release and reversible shape deformation and recovery.
The basic material is i-based alloy.

However, in catheter guide wires that use the above-mentioned T1Ni alloy material with simple elastic properties as a core material,
As elongation deformation increases, the load required for the deformation increases almost linearly, making it impossible to perform operations such as intravascular introduction with constant stress, which causes physiological pain for both doctors and patients. It had the disadvantage of giving away.

Therefore, conventionally, Ti-Ni alloy is usually 30 to 4
After performing the cold working of 096, heat treatment at 400-500℃ produces an improved annealed material, which prevents increases in elongation deformation etc. even under constant stress in one body (approximately 37℃). (hereinafter referred to as superelastic properties),
It was desired to obtain a core material for a catheter guide wire that can reversibly absorb and release energy and reversibly deform and recover its shape (Japanese Patent Application Laid-open No. 83-171570).

[Problems to be Solved by the Invention] However, the core material of the catheter guide wire using the conventional annealed Ti-Ni alloy material.

Compared to a core material made of stainless steel wire, its rigidity is about 1/2 lower, making it difficult to guide the catheter to the desired site within the human body against stress such as muscle contraction. was there.

In addition, a conventional Ti-Ni alloy annealed material is used at the tip of the core material to impart superelastic properties.

Even if the substrate part is made of stainless steel wire or the like to provide high rigidity and these are connected as a core material, the tip of the core material and the substrate part are manufactured separately, and
Not only is it complicated to connect the tip and substrate parts to each other, but one composition component is different from each other, so it is necessary to increase the bonding strength between the annealed material and the stainless steel wire, and mechanical restraint such as caulking is also required. There is a drawback that.

On the other hand, in the conventional annealed Ti-Ni alloy material.

(This is because 11 is simply given superelastic properties.

On the contrary, it is not possible to bend the tip of the guidewire core material into the desired shape depending on the target area, making it difficult to shape the tip in a manner that is responsive to clinical practice. There was a drawback in that the core material of the catheter guide wire with a diameter had to be prepared in advance.

In view of the above-mentioned 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 portion of the core material and the substrate portion of the catheter guide wire, and to make the distal end portion of the core material and the substrate portion of the catheter guide wire have substantially the same composition. The core of the catheter guidewire has a tip part and a matrix part that are integrally formed with a component, and the tip part is made flexible at least at body temperature (37°C), while the matrix part maintains high rigidity. It is to provide materials.

In addition to the first technical problem described above, the second technical problem of the present invention is that the tip of the core material of the guide wire can be bent into a desired shape depending on the target area. Another object of the present invention is to provide a core material for a catheter guide wire that has excellent workability and has plasticity that can maintain its deformed shape even in an environment of 80° C. such as hot water used clinically.

[Means for Solving the Problems] According to the present invention, there is provided a core material of a catheter guide wire having a distal end portion and a substrate portion integrally formed with each other,
The tip portion has substantially the same compositional components constituting a Ti-Ni alloy, and the compositional components constituting the T1 Ni-based alloy are, in atomic percent, N i 50.3
~52. Oat%.

A core material for a catheter guide wire is obtained, which contains a remainder of Ti and is characterized in that the annealing temperatures of the distal end portion and the substrate portion are different from each other.

Further, according to one aspect of the present invention, the tip portion is formed of the Ti-Ni
A core material for a catheter guide wire is obtained, which is characterized in that the base alloy is substantially heat-treated at 400-500°C, and the substrate portion is heat-treated at 400-500°C.

Further, according to the present invention, the tip portion is formed by subjecting the T/Ni alloy to a heat treatment of substantially 700°C or higher, has substantially superelastic properties at 37°C, and has superelastic properties at 80°C. A core material for a catheter guide wire is obtained, which is characterized by having plasticity even when the shape is deformed as described below.

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

Here, of the T1/Ni alloy, Nt is 50.3aL
% or more means that the intermediate phase transformation due to aging treatment is 50% or more.
At less than 3aL%, it is difficult to obtain 1 In addition, substantially 700℃ (
This is because it becomes difficult to undergo plastic deformation at 37°C due to heat treatment at 600 to 1000°C, and cannot escape from the conventional shape memory region. Further, the reason why N1 is set to be less than 52,031% is because if it exceeds 52.0 at%, workability deteriorates and there is a practical problem.

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

1. 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.

(2) Preparation Step First, a Ti--Ni alloy consisting of 51 atomic percent Ni and the balance Ti was obtained by high-frequency vacuum melting. Note that an arc melting method, an electron beam melting method, or a powder metallurgy method may also be used.

The obtained Ti-Ni alloy was solution treated at 900 to 1000°C, then hot forged and hot rolled at about 900°C,
Then, by cold working (final cold working rate 50%), 0
．． It was processed into a wire rod with a size of 5+uφ.

(Straight line treatment process (substrate part treatment process) For thermal straightening, straight line treatment was continuously performed for 5 minutes at 300°C over the entire 0.5 mm diameter wire to improve the straightness. provided.

■Superelasticity treatment process (tip treatment process) The obtained wire was cut into 2m lengths, and only the approximately 50n length from the cross section was heat treated by holding it in a salt bath maintained at approximately 400°C for 10 minutes. It was then rapidly cooled and used as the tip.

■Superelastic property test The tip part (No. 2) of the wire rod and the remaining part are
1), and the stress of each part under body temperature (37℃) -
Strain curves were measured. In addition, as a comparative example, 1.8-
An 8-sten 1-noss wire (No. 4) was also measured. The results are shown in FIG.

As a result, in the sample of the substrate part (No. 1), 100 kg
It shows a stress value exceeding f/mm2, which is higher than that of 18-8 stainless steel wire (magic 4). - side, tip (
Magnetic 2) has a clear yield (stress value of 60k) at 1% strain.
gf/mm2), indicating that it has extremely excellent superelastic properties.

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

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

Further, the heat treatment at 400°C in the superelasticity treatment step for the tip portion 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.

1.2nd Example--Similar to the 1st Example, ■Academic process and ■Linear processing process (
The following superelasticity treatment step (tip portion treatment step) was performed using the wire that had undergone the steps up to the substrate portion treatment step).

First, cut the obtained wire into a 2m dimension with a radius of approximately 5mm from the end surface.
Only the 0 mm length was held in a salt bath maintained at about 700° C. for 2 minutes, and then rapidly cooled, and this was used as the tip (3).

Next, the stress-strain curve of the tip (Na3) of the wire at body temperature (37° C.) was measured. The results are shown in FIG.

As a result, the sample at the tip (Nα3) treated at 700°C was
At a strain of 1%, only a slight plastic deformation was observed;
It is smaller than the amount of plastic deformation (gc residual strain) of the 8-8 stainless steel wire, and similar to the tip part (No. 2) of the first example, yielding is also observed from about 1% strain.
It can be seen 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 (3) treated at 700°C retained a large amount of plastic deformation.

From this, the tip part treated at 700°C, which has excellent plasticity (
It can be seen that by using the sample No. 3) for the tip of the core material of a catheter guide wire, it can be deformed into any shape suitable for clinical use.

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

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 nearly uniform outer diameter.

The synthetic resin coating 4 is made of polyethylene.

Polyvinyl chloride, polyester, polypropylene polyamide, polyurethane, polystyrene, fluororesin, silicone rubber, or their respective elastomers and composite materials are preferably used. and.

It is preferable that the synthetic resin coating 4 is flexible enough not to interfere with the curvature of the inner core 2, and has a smooth outer surface with no irregularities. In addition, the synthetic resin coating 4 is coated with an anticoagulant such as heparin or urokinase, or an antithrombotic material such as silicone rubber, a block copolymer of urethane and silicone (registered trademark Abcosan), or hydroxyethyl methacrylate-styrene copolymer. You may. Furthermore, the friction properties of the guide wire 1 may be reduced by forming the synthetic resin coating 4 from a resin having a low friction surface such as fluororesin, or by applying a lubricant such as silicone oil to the outer surface of the synthetic resin coating 4. good. Furthermore, in the synthetic resin forming the synthetic resin coating 4, Ba, W
It is preferable to mix a finely powdered X-ray contrast substance made of a single metal or a compound such as Bi, Pb, etc. By doing this, the guide wire 1 being introduced into the blood vessel is
It becomes easy to confirm the overall position of the As mentioned above, the synthetic resin coating 4 has a fairly uniform outer diameter. The term ``uniform'' does not mean that the tip is completely uniform, but may be slightly narrower at the tip. in this way.

By making the guide wire substantially 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 OJO to 0.84 mm, and the wall thickness of the core material 2 on the main body 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 the synthetic resin, and is also fixed to the distal end portion and the substrate portion of the inner core 2. Alternatively, one synthetic resin coating 4 may be formed of a hollow tube and fixed to the inner core 2 at the distal and proximal ends of the inner core 2 or at an appropriate portion of the inner core 1 by adhesion or melt molding. 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 first synthetic resin covering M4. What is a lubricating substance?

A substance that has lubricating properties when wet. in particular.

There are water-soluble polymer substances or their derivatives.

That is, the core material 2 of the guide wire in this embodiment has a total length of 1.800+u and a tip diameter of 0.06 m1. The diameter of the rear end was about 0.25 mm, and the diameter was tapered from the tip toward the tip by 120 mm.

Further, the entire outer surface of the core material was coated with polyurethane containing 45% by weight of fine tungsten powder (diameter of about 3 to 4 .mu.I1) so that the overall outer diameter was approximately uniform to form a synthetic resin coating. and 5.0 f in tetrahydrofuran
A solution in which maleic anhydride ethyl ester copolymer was dissolved so that the amount was 10%.

x'/li L and a maleic anhydride ethyl ester copolymer were fixed on the surface of the synthetic resin film formed from the above polyurethane to form a lubricating surface.

The total length of this guide wire is approximately 1800 mm.

The overall diameter is 0.36 ms.

[Effects of the invention] As can be seen from the above explanation, according to the present invention, Ti-N
Using substantially the same compositional components constituting the i-based alloy,
Since the tip of the core material of the catheter guide wire and the substrate are configured, there is no need to separately manufacture and connect the tip and the substrate, and the tip and the substrate can be integrally formed.
At least under body temperature (37° C.), only the tip portion maintains flexibility while the substrate portion maintains the rigidity of the Ti/Ni alloy itself, making it possible to provide a core material for a catheter guidewire.

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
It is possible to provide a catheter guide wire core material and a catheter guide wire that have excellent workability and have plasticity that can maintain their deformed shape even in an environment of 80° C. such as hot water used clinically.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a stress-strain curve measured at body temperature (37°C) under stress during tension of a Ti-Ni alloy containing 51 at% Ni, and FIG. 2 is a diagram showing a synthetic resin according to an example of the present invention. FIG. 2 is a cross-sectional view of a catheter guide wire coated with. NO, 1... Substrate part related to the first embodiment of the present invention, N
α2...300°C x 10 related to the first embodiment of the present invention
Tip portion subjected to heat treatment for 2 minutes, Na3... Tip portion 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. Figure 1 Strain

Claims (1)

[Scope of Claims] 1) A core material of a catheter guide wire having a distal end portion and a matrix portion that are integrally formed with each other, wherein the distal end portion and the matrix portion are made of a substantially Ti-Ni based alloy. The compositional components constituting the Ti/Ni alloy are Ni50.3-52 in atomic percent.
．． A core material for a catheter guide wire, comprising 0 at% and the remainder Ti, wherein the annealing temperature of the Ti/Ni alloy is different between the distal end portion and the substrate portion. 2) In the core material of the catheter guide wire according to claim 1, the tip portion is made of substantially 400% of the Ti/Ni alloy.
A core material for a catheter guide wire, characterized in that the substrate portion is heat-treated at a temperature of ~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 made of substantially 700% of the Ti/Ni alloy.
1. A core material for a catheter guide wire, characterized in that the core material is heat-treated at a temperature of 37° C. or higher, has superelastic properties at 37° C., and has plasticity against shape deformation at 80° C. or lower. 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.