JPH04187160A - Core material of catheter guide wire and catheter guide wire - Google Patents

Abstract

PURPOSE:To make it possible to keep either or both characteristics, namely, rich. contrast properties and high spring rigidity by using a TiPd alloy combining one or two or more of W, Ta, V, Cr, Mn, Ni, Fe, Co and Cu. CONSTITUTION:In a core material of a guide wire having an apex part and a base part integrally constituted each other, at least the apex part consists of a TiPd-type shape memorizing alloy. The TiPd-type shape memorizing alloy has a compsn. which consists of 45-51at% Pd and the, balance Ti and wherein a part of pd is substd. with 1.0-30at% sum of at least one of v, Cr, Mo, Ni, Fe, Co and Cu and has an elastic function at least at body temp. (37 deg.C). In addition, it has a compsn. wherein a part of Pd is substd. with either W or Ta or 1.0-30.0at% sum of them. In addition, it has a compsn. wherein a part of Pd of the TiPd (W, Ta) alloy is substd. with 1.0-30.0at% sum of at least one among V, Cr, Mn, Ni, Fe, Co and Cu and exhibits elastic function at least at body temp. (37 deg.C).

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] Generally, a catheter guide wire is punctured from a blood vessel. After being introduced into the blood vessel with a Seldinger needle,
This is a medical device used to remove the Seldinger needle from the guide wire and guide the catheter in advance of the catheter to the target site within the main vessel, especially the blood vessel.

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

It is formed from a tip section that has a complicated shape and a substrate section that has a linear shape and is continuous to the tip section. In addition, the core material of the catheter guide wire can reversibly absorb and release energy at the biological temperature (≧37°C) as it loads and removes deformation stress, including twisting, that occurs during introduction into blood vessels and movement. It is necessary to have elastic properties that allow the shape to be deformed and restored.

Conventionally, core materials that maintain these properties have been made of coiled stainless steel wire or piano wire, or made of monofilament plastic.

On the other hand, it is well known that a TiNf alloy with an atomic ratio of about 1 exhibits a remarkable shape memory effect and superelasticity due to the reverse transformation of the thermoelastic martensitic transformation. Alloys exhibiting these properties include TiNi alloy, TiN1X alloy (X-C
u, Cr, Fe, Ag, V, Co-) and Cu-Z
There are dozens of types including Cu-based alloys such as 'n-A and Q, AuCd alloys, and AgCd alloys. Recently, TiPd alloys have been studied as high-temperature operating elements, and some of the Pd in TiPd alloys and TiPd alloys has been replaced with Fe and Cu.

It is shown in JP-A-46-1502 that a TiPdX alloy substituted with Co and Ni operates at a temperature of about 500°C.

Core materials that utilize the superelastic function of TiNi alloys are becoming widely used in catheter guide wires (
(Japanese Patent Application Laid-Open No. 60-63066).

[Problems to be Solved by the Invention] However, the X-ray contrast properties of TiNi alloys are poor, and the synthetic resin coating of the core material usually contains W, Ba, and Bi.

It was usual to include a substance with high contrast properties such as PB. Furthermore, guide wires for small blood vessels in the brain, peripheral organs, etc. use a thin wire with a diameter of φ0.2 mm to φ0.4 + nm as the core material, and the synthetic resin coating cannot be thickened.
The drawback was that metals such as metals had to be capped or coated.

Further, although the superelastic wire of TiNi alloy exhibits good flexibility, it has the drawback of lacking a sense of rigidity. For this reason, it is sometimes difficult to guide the guide wire to a desired site within the body against forces such as vascular contraction, which has unavoidable limitations in terms of use.

In view of the above drawbacks, a first technical object of the present invention is to provide a catheter guide wire core material that maintains X-ray contrast properties at least at the distal end.

In addition, the second technical problem of the present invention is at least 37°C.
The elasticity of the tip and substrate is maintained at the bottom.

Another object of the present invention is to provide a catheter guide wire that has rigidity at least in its substrate portion.

[Means for Solving the Problems] According to the present invention, in a core material of a guide wire having a distal end portion and a matrix portion integrally formed with each other, at least the distal end portion is made of a TiPd-based shape memory alloy. A core material for a catheter guide wire is obtained.

According to one aspect of the present invention, the TiPd-based shape memory alloy is a TiPd alloy consisting of Pd: 45 to 51 at% remaining Ti, and a portion of Pd is replaced by V, Cr, and Mo.

A core of a catheter guide wire having a composition in which at least one of Ni, Fe, Co, and Cu is substituted in a total amount of 1.0 to 30 at%, and exhibiting an elastic function at least at body temperature (737°C). wood is obtained.

Further, according to the present invention, the TiPd-based shape memory alloy is P
d TiP consisting of 45.0 to 51.0 at% remaining Ti
Part of the Pd in the d-alloy is either W or Ta.

Or 1.0 to 30. A core material for a guidewire is obtained, which is characterized by having a composition in which Oat% is replaced.

According to one aspect of the present invention, the TiPd(W).

Ta) Part of the Pd in the alloy is replaced by V, Cr, Mn, and Ni.

The amount of at least one of Fe, Co, and Cu is 1.0 or more
A core material for a catheter guide wire is obtained, which has a composition containing 80.0 at% substitution and exhibits an elastic function at least at body temperature (37° C.).

In addition, in the alloy according to the present invention, the Pd content of the basic TiPd alloy is set to 45.0 to 51.0 at% because if it is less than 45 at%, there are problems in workability and shape memory.

This is because if it exceeds 51 at%, processability will only deteriorate. Also the third. The amount of substitution of the fourth element is 1.0~
The reason for setting it to 30.0at% is 1. If the content is less than 30 at%, the effect of substitution is weak. If it exceeds 30 at%, the effect of substitution is noticeable, but the processability and elastic properties tend to deteriorate.

[Example code] Embodiments of the present invention will be described with reference to the drawings.

Part of the Pd in the Ti-50at%Pd alloy is V.

Cr, Mn, Ni, Fe, Co, Cu, W, and Ta
Various alloys substituted with 0 to 35 at% by 20% were melted in an argon arc furnace, and wire rods having a diameter of 1.0 mm were formed by hot working and cold working at a temperature of about 1000°C.

Cut a part of these wires to 1000'c
1. Ohr solution treatment was performed and the transformation temperature was measured by DSC. FIG. 1 shows the relationship between the amount of the third element added and the transformation temperature (martensite transformation start temperature - Ms humidity temperature).

Each element was added at a maximum of 35%, but Ms humidity temperature was 0°C.
The following alloys were excluded from Figure 2. In the figure, W in curve 11 and Ta in curve 12 have a weaker Ms temperature lowering effect than other additive elements.

Generally, in order to obtain elasticity near body temperature (37℃),
It is desirable that the Ms humidity temperature of the solution-treated alloy is 37°C or less. Obtaining an alloy that satisfies this purpose requires W
In the case of additive elements other than Ta, they can be used as one kind or in combination of two or more, and in the case of W and Ta, it is possible to arbitrarily select other elements in addition to one or two kinds of W and Ta. It was found that

Among the various alloys, T l 50P d 43W
7 (alloy-1), Ti5oPd43Ta7 (alloy-2).

T t 5oP d aaF e te (Alloy-3)
, T 15o P d 24Ni24 (alloy-4)
, T 15oP d 29W7 Fe 14 (alloy-
5) , T 150P d 19W7 N l 24
(alloy = 6) and comparative alloy T l 49N 15□ (
After cold working of each wire rod sample of Alloy-7) (processing rate 10%)
or more) 1000℃X10m1n and 4009CX10
The loading/unloading curve under 3% tension at 37° C. during the min treatment is shown in FIG. Alloy-11 Alloy-2 is 10
In the 00°C and 400°C treatments, the Ms humidity temperature exceeds 37°C and does not exhibit good elasticity. However, Alloy 1-31 Alloy-41 Alloy-51 Alloy-6 exhibits good elasticity because the Ms humidity temperature is 37° C. or lower. On the other hand, both alloys exhibit good elasticity after cold working.

The elastic properties of the TiPd-based alloy are compared to the comparative alloy T I 49N.
Although it is inferior to 15□ alloy and slightly different from the superelasticity that shows clear yielding, the elongation limit value that shows 1 elasticity is higher than that of conventional spring materials such as piano wire.

Furthermore, since the cold-worked Alloy-11 Alloy-2 exhibits relatively good elasticity, it was found that it can be sufficiently applied as a core material for catheter guide wires, which is the object of the present invention.

Next, when looking at the rigidity as a spring material, it can be seen that the two alloys according to the present invention each exhibit a stress value about 1.5 times or more compared to the comparative alloy.

Regarding contrast properties to X-rays, generally the atomic weight (A) of the element
increases in proportion to the size of For this reason, Ba.

Heavy metals such as W, Ta, and Pd or noble metals such as Au and Pt are selected as contrast effect elements. W, Ta in the alloy of the present invention
In particular, an alloy containing one or both of W and Ta in an amount of 5 at % or more obtained contrast performance 1.5 times or more compared to a TiNi alloy.

The composition of the alloy according to the present invention can be arbitrarily selected depending on whether the objective is to improve contrast performance, increase spring stiffness, or both. That is, the combination can be determined by the Ms temperature effect of each element shown in FIG. 1 and the contrast effect of the added amounts of W and Ta.

Next, embodiments of the guide wire will be described.

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, synthetic rubber, elastomers, composite materials, etc. 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 2 synthetic resin coating 4 includes anticoagulants such as heparon and urokinase, silicone rubber, a block copolymer of urethane and silicone (registered trademark Abcosan), hydroxyethyl methacrylate, etc.
It may also be coated with antithrombotic materials such as styrene copolymers.

Furthermore, the friction properties of the guide wire 1 may be reduced by forming the synthetic resin coating 4 with 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, Bi,
It is preferable to mix a finely powdered X-ray contrast substance made of a single metal such as Pb or a compound, and by doing so, it becomes easier to confirm the entire position of the guide wire 1 being introduced into the blood vessel. 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 0.30 to 0.64 degrees, the main body portion 2a of the core material 2
The wall thickness on the top is in the order of 0.03 to 0.30, 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 and the proximal end of the inner core 2. Alternatively, the two synthetic resin coatings 4 may be formed of a hollow tube and fixed to the inner core 2 by adhesion or melt molding at the distal and proximal ends of the inner core 2 or at an appropriate 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 second synthetic resin coating 4. 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 of the second embodiment has a total length of 1800 mm, a tip diameter of O, O[i+nm, a rear end diameter of 0.25 mm, and a tapered section of 120 mm from the tip toward the tip. I created one with a reduced diameter.

Furthermore, the entire outer surface of the core material was coated with polyurethane containing 45% by weight of fine tungsten powder (particle size of approximately 3 to 4 μm) so that the overall outer diameter was approximately 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. The union was fixed and a lubricious surface was formed.

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

The overall diameter is 0. Hmm.

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

W, Ta, V, Cr, Mn, Ni, Fe, Co.

TiPd containing one or more Cu elements in combination
By using a series alloy, it has excellent contrast properties.

Alternatively, it is possible to provide a catheter guide wire core material that exhibits either or both of high spring stiffness.

Furthermore, among the alloys according to the present invention, Ti-Pd-Fe, T
Combination alloys such as i-Pd-W-Fe.

Due to its excellent subject compatibility, it can be used in applications where there is a high possibility of direct contact with the human body, such as long-term indwelling.

[Brief explanation of the drawing]

Figure 1 shows the relationship between the Ms humidity temperature addition amount of the alloy added in the form of TiPdX (X=W, Ti. 5050-xx V, Cr, Mn, Ni, Fe, Co, Cu). . FIG. 2 shows Ti. . P d 4aW 7 (Alloy-1). Ti Pd Ta (alloy-2), Ti
5oP d34Fe (alloy-3), Tl 5o
Pd 24N 12B (alloy B-4), T 15oPd29W7F e14 (alloy-5
). T l 50 P d L9W r N 124 (Alloy-6) and T I 49N l 51 (Alloy-7
) each wire rod was cold worked and heated at 1000℃ x 10 m.
It shows loading/unloading type curves under 3% tension at 37°C for in treatment and 400°C Xl0nun treatment. FIG. 3 is a side view of a catheter guide wire coated with a synthetic resin according to the present invention. In the figure, 1... Guide wire, 2... Inner core, 2a.
...Inner core body, 4...synthetic resin.

Claims (5)

[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 at least the distal end portion is made of a TiPd-based shape memory alloy. . (2) In the catheter guide wire core material according to claim (1), the TiPd-based alloy has Pd: 45.0 to
A composition in which a part of Pd in a TiPd alloy consisting of 51.0 at% and remaining Ti is replaced with at least one of V, Cr, Mn, Ni, Fe, Co, and Cu in a total amount of 1.0 to 30.0 at%. A core material for a catheter guide wire, which has an elastic function at least at body temperature (37°C). (3) In the catheter guide wire core material according to claim (1), the TiPd-based alloy has Pd: 45.0 to 5
A catheter guide characterized by having a composition in which a part of Pd in a TiPd alloy consisting of 1.0 at% and remaining Ti is replaced by at least one of W and Ta in a total amount of 1.0 to 30.0 at%. Wire core material. (4) In the core material of the catheter guide wire according to claim (3), a part of the Pd of the TiPd alloy is replaced by V, C.
It has a composition in which at least one of r, Mn, Ni, Fe, Co, and Cu is substituted in a total amount of 1.0 to 30.0 at%, and has an elastic function at least at body temperature (■37 ° C.) Core material for catheter guide wires. (5) A catheter guide wire characterized in that the core material of the catheter guide wire according to any one of claims (1) to (4) is coated with a synthetic resin.