JPH02289266A - 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 by a method wherein at least a part of a surface except a blood introduction tip part is covered with an inorganic film. CONSTITUTION:A Ti-51at% Ni series alloy consisting of 51at% in atomic percent Ni and balancing Ti is produced by high frequency vacuum dissolution, or may be produced by an arc dissolution method, an electronic beam dissolution method, or a powder metallurgic method. After the produced Ti.Ni series alloy is treated at 900-1000 deg.C to produce a solution, hot forging and hot rolling are applied at approximate 900 deg.C, and thereafter, the alloy is processed by cold treatment to produce a wire rod. Heat treatment (annealing) is applied under tension on the whole of the so produced wire rod at 400 deg.C for 10 minutes to provide linearility and superresilient characteristics. The whole surface of the wire rod is then coated with Ni by electric plating, stainless by deposition plating, silicon carbide by sputtering, and a titanium nitride by sputtering. Each of the coated wire rods is cut to given lengths, and a film is removed from the cut end surface only by a length.

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 Catheter Guide Wide.

It is composed of a tip section with a complex shape and a matrix section with a linear shape, and is capable of loading and removing deformation stress including twisting that occurs during introduction and movement into blood vessels at biological temperature (approximately 37 degrees Celsius). Ti--Ni alloy is generally used as the basic material because it is required to have elastic properties that allow reversible energy absorption and release as well as reversible shape deformation and recovery.

However, in a catheter guide wire using the above-mentioned T1Ni alloy material with simple elastic properties as a core material,
As the elongation deformation increases, the load required for the deformation increases almost linearly, so the work of introducing it into the blood vessel can be done with constant stress, which causes physiological pain for both the doctor and the patient. I had a problem with giving it away.

Therefore, conventionally, Ti-Ni alloy is usually 30 to 4
After 0% cold working, heat treatment at 400-500°C produces an improved annealed material,
As a result, even in a single body (approximately 37° C.), elongation and deformation increase even under constant stress, which is hereinafter referred to as superelastic property. ), a catheter guidewire core material capable of reversibly absorbing and releasing energy and reversibly deforming and restoring its shape was obtained (Japanese Unexamined Patent Publication No. 88-171570).

[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 using stainless steel wire, its rigidity is about half as low, making it difficult to guide the catheter to a desired site within the human body against stress such as muscle contraction. That is, for example, the torque transmittance for transmitting a twist and the rigidity for transmitting a push were insufficient for the operation with two hands.

In view of the above-mentioned drawbacks, the technical problem of the present invention is to provide a core material for a catheter guide wire that maintains flexibility in the distal end portion and maintains rigidity in the substrate portion at least at body temperature (37°C). An object of the present invention is to provide a catheter guide wire.

[Means for Solving the Problems] According to the present invention, in the core material of a catheter guide wire made of a superelastic alloy, at least a part of the surface excluding the blood vessel introduction tip is covered with an inorganic coating. A core material for a catheter guide wire is obtained.

According to the second aspect of the present invention, there is obtained a core material for a catheter guide wire, wherein the inorganic coating is a Ni coating.

According to one aspect of the present invention, a core material of a catheter guide wire having a distal end portion and a substrate portion has a clad structure surrounding the substrate portion.

A core material for a catheter guide wire is obtained, in which the tip portion has superelastic properties.

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

First Example - In this example, a core material of a catheter guide wire in which the tip part maintains flexibility and the substrate part maintains rigidity under one body temperature (37 DEG C.) will be described.

(2) Preparation Step First, a Ti-51 at% Ni alloy consisting of 51 at% Ni and the remainder Ti was obtained by high frequency vacuum melting. In addition, 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%),
It was processed into a wire rod with a size of 0.5 mφ.

■Superelasticity treatment process The entire wire of size 0, 5II■φ is heat treated (annealed) at 400°C for 10 minutes under tension to give it linearity and to improve its superelastic properties. Granted.

(2) Initial superelastic property test The stress-strain curve of the heat-treated wire (NllL2) at a strain of 3% (elongation) at body temperature (37°C) was measured. As a comparative example, 18-8 stainless steel wire (Mag 1) was also determined at 71 IJ. The results are shown in FIG.

As a result, the heat-treated wire rod (section 2).

Even when a strain of 3% was applied, the strain was completely eliminated as soon as the load was released. That is, it can be seen that the wire (Nα2) has superelastic properties that allow it to easily absorb and release reversible energy and reversibly deform and recover its shape by heat treatment, loading, and removal. Comparative example 18-8
In the stainless steel wire (NcL1), at a strain of 3%, permanent deformation remains completely, and the superelastic properties seen in annealed Ti-Nf alloys are not observed.

On the other hand, regarding the rigidity, wire rods c and N(
L 2 ) has a tensile strength of 50 at a strain of 3%.
kgf/am2, whereas for 18-8 stainless steel wire (No. 1), it is approximately 100kgf/mm2
It shows. This means that heat-treated wire rods (Chen 2
) has superelastic properties, but compared to conventional stainless steel wires, it lacks rigidity and exhibits weakness.

■N (film treatment process Next, the entire surface of the wire that has been subjected to multiple heat treatments.

Ni by electroplating (k3), stainless steel by vapor deposition plating (Na4), silicon carbide (S)
iC) by sputtering (Nα5) and titanium nitride by sputtering (Nα6) to a thickness of 25 to 50 μm, respectively.

■Intermediate superelastic property test For each of the coated wire rods (Chen 3-6).

Stress-strain curves were measured at body temperature (37°C). The results are shown in FIG.

As a result, the coated wire rods (magic 3 to 6) are as follows.

All exhibited curves similar to those of 18-8 stainless steel wire (Magnetic 1), and were found to have high rigidity.

■Tip treatment process Each of the coated wire rods (N 3 to 6) is
It was cut into m dimensions, and the coating was removed only from a length of about 50 m+e from the end face. A chemical method using aqua regia was used for removal.

Note that mechanical methods such as polishing may also be used.

(2) Final superelastic property test The stress-strain curve at two body temperatures (37°C) was measured for each film-removed tip of the coated wire (llIa3-6). As a result, superelastic properties similar to those of the heat-treated wire rod (Magic 2) in the initial superelastic property test were observed.

As a result, it is understood that a core material having superelasticity at the tip and rigidity at the remaining matrix portion can be obtained.

1. Second Embodiment - This embodiment relates to a core material of a catheter guide wire having a clad structure.

■ Preparation process 5. Preparation process of the Ti eNi alloy obtained in the preparation process of the first example. A wire rod with a size of Q opening φ and an inner diameter of 5.1 φ.

It is inserted into an 18-8 stainless steel pipe with an outer diameter of 6.0 mm to form a cladding with a core made of Ti-N1 alloy and an outer skin made of stainless steel.

■ Swaging process Wire rod in clad state is swaged to 0°7φ
After that, it was made into 0.5+nφ by cold working.

Got the clad wire.

(2) Super-elasticity treatment process The obtained clad wire was heat-treated at 40°C for 10 minutes to impart superelastic properties.

■Exterior skin superelasticity test About the heat-treated cladding wire (7).

The stress-strain curve was measured at body temperature (37°C). The results are shown in FIG.

As a result, the heat-treated clad wire (Na7) was 1
It was found that it exhibited a similar curve to the 8-8 stainless steel wire (Seed 1) and had high rigidity.

■Tip processing process The outer skin of the heat-treated clad wire (Nα7).

As in the first example, the coating was removed from the end face only by a length of about 501 II, exposing the core from the outer skin. A chemical method using aqua regia was used for removal.

(2) Core Superelasticity Test The stress-strain curve at 1 body temperature (37° C.) was measured for the core (not shown) of the heat-treated clad wire. As a result, the wire rod (No.
, 2) was found to have similar superelastic properties.

The core was tapered by chemical treatment (hydrofluoric acid), and then the entire length was coated with a polymer such as polyurethane.

Third Embodiment As shown in FIG. 2, 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 [14] is 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 material made of a single metal or a compound such as Bt, Pb, etc., and by doing so, it is easy to confirm the overall position of the guide wire 1 being introduced into the blood vessel. becomes. The synthetic resin coating 4 is
As mentioned above, it 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 0.84V.
The wall thickness at the top is between 0.03 and 0.30 m5+, preferably between 1.05 and 0.20 mm.

Further, it is preferable that the first synthetic resin coating 4 is tightly adhered to the inner core 2 by the second 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) is attached to a curved surface such as a hemisphere as shown in FIG. 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 has lubricating properties when wet. in particular.

There are water-soluble polymer substances or their derivatives.

An example as a guide wire will be specifically described.

As core material 2, the total length is 1800m+s and the diameter of the tip is 0.
゜06〜The diameter of the rear end is 0.25mm, and the diameter is 12mm from the tip.
A piece with a diameter of 0 mm tapered toward the tip was created.

Further, the entire outer surface of the core material was coated with polyurethane containing 45% by weight of fine tungsten powder (particle size: about 3 to 4, B) so that the overall outer diameter was 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 a maleic anhydride ethyl ester copolymer was The union was fixed and a lubricious surface was formed.

This guide wire has a total length of approximately 1800ms+
.

The overall diameter is 0.38 mm.

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

It is possible to provide a core material of the catheter guide wire and a catheter guide wire in which the tip portion maintains flexibility while the substrate portion maintains rigidity at least under body temperature (37° C.).

[Brief explanation of drawings]

Figure 1 is a diagram showing the stress-strain curve determined by 71#1 at body temperature (37°C) under stress during tensile stress of a Ti-Ni alloy containing 51 at% Ni, and Figure 2 is a diagram showing the stress-strain curve of a Ti-Ni alloy containing 51 at% Ni. FIG. 2 is a cross-sectional view of a synthetic resin-coated catheter guide wire according to an embodiment. No. 1...18-8 stainless steel wire, Nα2...
The tip part was heat-treated at 400° C. for XIO minutes according to the first embodiment of the present invention, and the wire rod was electroplated with Ni according to the first embodiment of the present invention. Nci, 4... Wire rod coated with stainless steel by vapor deposition plating, N11L5 related to the first embodiment of the present invention
. . . Wire rod coated with silicon carbide (SiC) by sputtering according to the first embodiment of the present invention, magnetic 6.
...Wire coated with titanium nitride by sputtering, Na7, related to the first embodiment of the present invention...Clad wire subjected to heat treatment for 400"CX10 minutes, related to the second embodiment of the present invention.1... Catheter guide wire. 2...Core material, 2a... Core material body, 4...-Synthetic resin coating. Fig. 2

Claims (1)

[Scope of Claims] 1) A catheter guide wire characterized in that, in the core material of the catheter guide wire made of a superelastic alloy, at least a part of the surface excluding the blood vessel introduction tip is covered with an inorganic coating. core material. 2) A core material for a catheter guide wire, wherein the inorganic coating according to claim 1 is a Ni coating. 3) A core material for a catheter guide wire, wherein the inorganic coating according to claim 1 has an alloy clad structure. 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.