JPH02289265A - Material for core of catheter guide wire, core of catheter guide wire and catheter guide wire - Google Patents

Abstract

PURPOSE:To enable cold bending of the tip part of a guide wire in a given shape according to an object portion by a method wherein heat treatment is applied on a material used for a core having a Ti.Ni.Fe series alloy containing Ni, Fe, and Ti in a specified atomic percent to produce a core for a catheter guide wire. CONSTITUTION:Heat treatment of 400-1000 deg.C (preferably 400-500 deg.C) is substantially applied on a material used for the core of a catheter guide wire having a Ti.Ni.Fe series alloy, containing 45.0-51.0 at% in atomic percent Ni, 0.5-5.0at% Fe, and balancing Ti and excellent cold processability to produce the core of a catheter guide wire having a superresilient alloy material and substantially showing super resilient characteristics at 37 deg.C and plasticity against shape deformation at 80 deg.C or less. At least the tip part of the core is a superresilient alloy material, and further the core may be covered with synthetic resin.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention relates to a material for a core material of a catheter guide wire which is a medical instrument, a core material of a catheter guide wire using the material, and a core material for a catheter guide wire using the material. Regarding the catheter guide wire used.

[Prior Art] In general, a catheter guidewire is introduced into a blood vessel using 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 catheter is inserted into a living body. A medical device that guides a catheter in advance of a catheter to a target site within a blood vessel, particularly a blood vessel.

For this reason, the core material of the catheter guide wire.

6J due to the loading and removal of deformation stress including twisting that occurs during introduction and movement into blood vessels at biological temperature (approximately 37°C)
Generally, 18-8 stainless steel is used as the basic material because it is required to have elastic properties that allow for reversible energy absorption and release and reversible shape deformation and recovery.

However, when a processed Ti-Ni alloy material with simple elastic properties is used as a core material, as the elongation deformation increases, the load required for the deformation also increases almost linearly, resulting in an increase in the amount of stress inside the blood vessel. There is a problem in that the introduction work cannot be performed with constant stress, causing physiological pain to both the doctor and the patient.

Therefore, in the past, by using an annealed alloy that is improved by annealing a Ti-Ni alloy, it exhibits increased elongation deformation even under constant stress in a single body (approximately 37 degrees Celsius) (hereinafter referred to as superelastic properties). .

A catheter guidewire core material capable of reversibly absorbing and releasing energy and reversibly deforming and restoring its shape has been obtained (Japanese Patent Application Laid-Open No. 171570/1983).

[Problem 8 to be solved by the invention] However, since the annealed Ti-Ni alloy used as a material for conventional catheter guide wires has only superelastic properties, the tip of the guide wire There was a drawback that it was difficult to cold bend the section into a desired shape depending on the target area.

In addition, in order to fix the desired shape using the annealed Ti-Ni alloy, the annealed alloy must be heated again at 400°C.
Heat treated at higher temperatures.

It is necessary to add shape. This makes it difficult to shape the distal end portion in a way that is responsive to clinical practice, and it is necessary to prepare in advance core materials for catheter guide wires having several types of distal end shapes.

Therefore, in view of the above-mentioned drawbacks, the first technical problem of the present invention is to provide a material for the core material of a catheter guide wire that has excellent cold workability and to obtain a core material for a catheter guide wire having a desired shape. An object of the present invention is to provide a catheter guide wire with the following features.

Further, the second technical problem of the present invention is substantially.

An object of the present invention is to provide a core material for a catheter guide wire that exhibits superelastic properties at 37° C. and has excellent plasticity against shape deformation at 80° C. or lower, and a catheter guide wire equipped with the core material.

A third technical problem of the present invention is to effectively utilize the core material of the catheter guide wire to cold bend the distal end of the guide wire into a desired shape depending on the target area. An object of the present invention is to provide a core material for a catheter guide wire that can be used as a core material, and a catheter guide wire equipped with the core material.

[Means for Solving the Problems] According to the present invention, at 1 atomic percent, Ni45.0 to 5
1. Ox1%, FeO, 5-5. A material for a core material of a catheter guide wire having excellent cold workability and having a Ti-Ni-Fe alloy containing 1% Ox and the remainder Ti is obtained.

Further, according to the present invention, the material for the core material of the catheter guide wire is substantially heat-treated at 400 to 1000°C (
Preferably, it has a superelastic alloy material produced by subjecting it to a temperature of 400 to 500°C.

A core material for a catheter guide wire is obtained, which exhibits superelastic properties at 37°C and has plasticity against shape deformation at temperatures below 80°C.

According to one aspect of the present invention, there is obtained a core material for a catheter guide wire, wherein at least the distal end portion of the core material is made of the superelastic alloy material.

According to one aspect of the present invention, there is obtained a catheter guide wire characterized in that the core material is coated with a synthetic resin.

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

Example 1 - First, as listed in Table 2-1, - the present invention alloy Na 3 to 5. 9 to 11 and a conventional alloy Nα1° having a conventional Tt-Ni alloy composition and a comparative alloy Nα2, 7.8 as a comparative example were produced by a high frequency vacuum melting method. Note that an arc melting method, an electron beam melting method, or a powder metallurgy method may also be used.

Each of the alloys N1L1 to 11 having such a composition is 900 to 1000
After solution treatment at ℃, hot forging at about 900℃.

Hot rolled, then cold worked to draw to a diameter of 0.7 mm, and strain relief annealed at about 900°C.
It was processed to a size of 5 miφ.

Margin below (Workability test) Table 1 shows the hot workability and cold workability of each alloy Nα] to 11 observed during the above hot working and cold working.

Results 1 Invention alloy Nα3-5. Nα9 to 11 and comparative alloy No. 2 are better than conventional alloy No. 1.

It can be seen that the cold workability is generally excellent.

Furthermore, as can be seen from the two comparative alloys Nα7 and 8, when the amount of Fe added exceeds 5.0 at%, the hot workability deteriorates!
Not only did the diameter become 1, but also the final cold working from 0.7 mmφ to 0.5 mmφ was impossible.

That is, Fe within the range of 0.25 to 5.0 at%,
Invention alloy No. 3 to 5 added to Ti-Ni. Demon 9
~] It can be seen that hot workability and cold workability are generally improved for Comparative Alloy No. 1 and Comparative Alloy No. 2 compared to the conventional and Comparative Alloy No. 1.7.8.

(Superelastic property test) Next, each alloy Nα1 to 11 processed to a size of 0.5 m + sφ was subjected to 900°C, 700°C, 600°C, respectively.
℃, 500℃, 400℃ and 1300℃ for 1 hour (annealing), then room temperature (20℃) and body temperature (37℃).
A tensile test (3% strain) was conducted at 71J11° C., and each stress-strain curve was determined as 71J11. In addition, comparative alloy Nα
No tensile tests were performed on the 7.8 alloy as it was not possible to cold work it.

Figure 1 shows the results of measurements at room temperature (20°C) under tensile stress for conventional alloy Na 1 and gold magnet 4 of the present invention.
The stress-strain curves are shown for the processed material (unannealed alloy) and the r100°C annealed alloy. In addition,
An example of commercially available 18-18 stainless steel wire is also shown.

As a result 1, the annealed alloy of the present invention alloy 4 is different from the conventional alloy 1
as annealed alloys as well as superelastic alloys.

It maintains supple superelastic properties like rubber, and we were able to find a yield stress where the stress remains constant despite changes in elongation.

Table 2 shows 4P1 at body temperature (37℃) under stress during tension.
Each alloy No. 1 to 11 for each different heat treatment temperature determined
The stress-strain curves of the annealed alloys are shown.

It can be seen that the heat treatment is appropriate.

In addition, in cases where repeated motion is not necessarily required, a superelastic alloy that absorbs and releases energy and reversibly deforms and recovers its shape under low stress levels can be created by heat treatment at 600°C or higher. You can also get it.

(Plasticity test) Next, for the conventional alloy and the alloy materials annealed at 500°C among the alloys of the present invention Na 1 to 11, the degree of Kunidume strain at the time of one bending stress release after bending at 90 degrees at 37°C and the degree of residual strain due to heating at 80°C, δ-1
The results are shown in Table 1-3.

As a result, in both the conventional alloy and the annealed alloys of the present invention alloys Nos. 021 to 11, in the cold-worked materials, the strain was eliminated as soon as the load was removed, but no clear yield point was observed.

On the other hand, superelastic properties showing clear yielding were obtained from materials heat-treated at temperatures above 400°C.

In addition, good superelastic properties can be obtained for both conventional alloys and invented alloys Nα1 to 11, which are baked with 400 to 5
It was 00℃. When it exceeds 600℃.

The yield stress level is about half that of the alloy annealed at 400-500°C, but on the contrary, the superelastic properties deteriorate, especially against repeated movements in tensile tests.

showed extreme deterioration.

Therefore, as a rope material for a catheter guide wire, it is possible to absorb and release reversible energy at the biological temperature (approximately 37°C) due to the loading and removal of deformation stress, including twisting, that occurs during introduction and movement into blood vessels. Since a superelastic alloy with superelastic properties that can deform and recover its shape is required, both the conventional alloy and the invention alloy Nal~11 have a Nal of 400~
As a result, the conventional alloy Na 1 returns to its original shape as soon as the stress is released in chamber IH due to its large superelastic effect, making it difficult to plastically work the conventional alloy Na 1. Furthermore, when heated to 80°C, even the slightest residual strain was eliminated. For this reason, in order to fix a conventional annealed alloy into a specific shape, it is necessary to
It is necessary to heat it to 0-500°C.

Further, although 0.25 at% of Fe was added to comparative alloy No. 002, almost no residual strain was observed.

The results were similar to those of the conventional alloy Nα1.

On the other hand, the present invention alloy Nα with addition of F e O, 5 at%
In 3.

The effect of the addition was recognized, with a residual strain of about 50% at 37°C. Further, even when heated to 80° C., a strain of about 1006 remained. F e 1. In the present alloys NO, 4 to 6, and 9 to 11 containing Oat% or more, almost 100% remained at 37°C, and 90% or more remained even when heated to 80°C.

Therefore, the alloy seeds 3 to 6.9 to 11 of the present invention containing F e O, 5aLX or more are 400 to 500 as in the conventional method.
It was possible to obtain plasticity to fix the deformed shape without the need for heat treatment at very specific temperatures in °C. In addition, it was possible to obtain plasticity that could maintain more than 90% of the deformed shape even in an 80°C environment such as hot water used clinically.

Next, as shown in FIG.
For alloy materials annealed at 20°C and 40°C.

The stress-strain curves at temperatures of 60°C and 80°C were observed in more detail. As a result, it was found that some strain remained even at 40°C, compared to bending at 90°C.

It is possible to fix the deformed shape even by heating at 40°C, indicating that the material has excellent plasticity for catheter guide wires. This means that the residual strain at 40°C is about 5%.

This is because the strain applied during use of a catheter guide wire is limited to about 1 to 2% at most.

This is because there is no problem with repeated deformation.

Also, in order to obtain more stable plastic deformation.

It can be easily understood from FIG. 2 that the deformation can be performed while heated to 60°C or 80°C.

From the above test results, a superelastic alloy is an annealed alloy obtained by heat-treating (annealing) a Ti-Ni-Fe alloy containing 0.5 at% or more of Fe at 400 to 500°C.

By using it as a core material for catheter guide wires, it can be cold bent (shape deformed) without losing its perfect superelastic properties at one body temperature (37°C), and it can be used at clinically effective operating temperatures (80°C or lower). ) can provide plasticity that maintains stable shape deformation. Note that if the annealing temperature exceeds 500℃, the superelastic properties at room temperature and body temperature will deteriorate, and on the contrary, the plasticity will increase. An annealing temperature exceeding 500°C is effective.

Embodiment 21 Invention alloy Nα4 shown in Example 1 and conventional alloy No.

1 and 0.7 m + *φ, approximately 9
Strain relief annealing is performed at a temperature of 0.5111+
Processed to 1φ.

After heat treating (annealing) the obtained composite alloy wire at 400° C. for 1 hour, a bending test was conducted for each alloy part. The results were similar to those shown in Table 3 of the first example.

As a result, the tip of the core material of the catheter guide wire was made into the alloy No. 4 of the present invention.

It can be seen that conventional alloy No. 1 can be used as the substrate. In other words, the tip of the core material.

By configuring a core material that can be easily deformed into a desired shape at a temperature of 80° C. or lower and exhibits superelastic properties that prevent the substrate from deforming easily.

A core material for a catheter guide wire that is suitable for clinical use can be obtained. Note that such a composite alloy wire is tapered only at its tip, and then coated over its entire length with a polymer such as urethane.

However, 1. When the composite alloy wire in this example is bonded to conventional stainless steel wire, piano wire, etc. to make a catheter guide wire, mechanical restraint such as caulking is required to increase the bonding strength. It is preferable.

Embodiment 3 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 polyethylene.

Polyvinyl chloride, polyester, polypropylene.

Polyamide, polyurethane, polystyrene, fluororesin, silicone rubber, or each elastomer and composite material 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 a hydroxyethyl methacrylate-styrene copolymer. It's okay. 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 material made of a single metal or a compound such as , Bi, Pb, etc., and by doing so, it is possible to confirm the entire position of the guide bar key 1 while it is being introduced into the blood vessel. becomes the product. 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, it is possible to reduce the damage 1a that the tip of the guide wire may cause to the inner wall of the blood vessel.

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 2a is 0.03 to 0.30 m+s, preferably is 0.05 to 0.20+I1m.

Further, it is preferable that the synthetic resin coating 4 is tightly adhered to the inner core 2 by the synthetic resin 5, and is also fixed to the distal end and the proximal end 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 at the distal and proximal ends of the inner core 2 or at an appropriate portion of the inner core 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 coating 4. What is a lubricating substance?

A substance that exhibits lubricity 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 1800 mm, a diameter of 0.06 mm at the tip, a diameter of 0.25 mm at the rear end, and a diameter of 120 mm from the tip tapers toward the tip. I created what I am doing.

Further, the entire outer surface of the core material was coated with polyurethane containing 45 mm% of fine tungsten powder (approximately 3 to 4 .mu.m in diameter) so that the overall outer diameter was approximately uniform to form a synthetic resin coating. and 5.0% by weight in tetrahydrofuran.
Dissolve the maleic anhydride ethyl ester copolymer in the following manner.

It was applied to the surface of the synthetic resin wave 1 made of the polyurethane described above to fix the maleic anhydride ethyl ester co-polymers and form a lubricating surface.

This guide wire has a total length of approximately 1800 mm.

The overall diameter is 0.3 [i++ns.

〔Effect of the invention] As can be seen from the above description, one aspect of the present invention is as follows.

Since a Ti-Ni-Fe alloy containing a predetermined amount of Fe is used, it is possible to provide a material for the core material of a catheter guide wire that has excellent cold workability.

Because we used a superelastic alloy that was annealed from the Ti-Ni-Fe alloy, it essentially showed superelastic properties at 37°C and also showed plasticity when deformed at temperatures below 80°C. A core material for a catheter guide wire with excellent workability can be provided.

In addition, since at least the distal end of the core material of the catheter guidewire is made of the above-mentioned catheter guidewire material, the distal end of the catheter guidewire can be cold bent into a desired shape depending on the target area. A core material can be provided.

[Brief explanation of the drawing]

Figure 1 shows the conventional alloy No. 11 and the invention alloy No. 1 among the results measured at room temperature (20°C) under tensile stress.
, 500°C and the finished mill (unannealed alloy) in 4
A diagram showing the stress-strain curve of an annealed alloy,
Figure 2 shows the alloys No. 5 of the present invention annealed at 500°C at 20°C and 40°C. FIG. 3 is a side view of a catheter guide wire coated with a synthetic resin according to the present invention. DESCRIPTION OF SYMBOLS 1... Guide wire, 2... Inner core, 2a... Inner core body part, 4... Synthetic resin. Figure 2 Strain Figure 1 Strain

Claims (1)

[Claims] 1) Ni45.0 to 51.0 at% in atomic percent
, Fe0.5-5.0at%, balance Ti/N
A core material for catheter guide wires that contains an i-Fe alloy and has excellent cold workability. 2) The alloy according to claim 1, wherein substantially 3
A core material for a catheter guide wire, which exhibits superelastic properties at 7°C and has plasticity against shape deformation at 80°C or lower. 3) A core material for a catheter guide wire, wherein at least a distal end portion of the core material is made of the superelastic alloy material according to claim 2. 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.