JPH08257132A - Medical guide wire - Google Patents

Abstract

PURPOSE: To provide a medical guide wire which allows keeping of softness of a tip part as intact with pliability and elasticity as a whole facilitating the shaping of the tip part with excellent operability and easier production. CONSTITUTION: The tip part 12a of a core wire 12 comprising a superelastic material is formed slender at a specified length and the outer circumference of at least the tip part 12a of the core wire 12 is made up of a shape memory resin film. The outer circumference of the core wire 12 is covered with a synthetic resin film to make a medical guide wire 11. The outer circumference of the synthetic resin film 13 is further covered with a hydrophilic resin film preferably because of improved lubricating property.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a medical guide wire used for inserting a catheter into a blood vessel, a ureter, a trachea or the like.

[0002]

2. Description of the Related Art In recent years, for example, in a cardiac catheterization test, a technique has been widely adopted in which a catheter is percutaneously inserted without incising the blood vessel and a drug such as a contrast agent is administered to the blood vessel.

The procedure for percutaneously inserting a catheter will be described with reference to FIG. 8 by taking an arterial puncture as an example. First, the artery 2 is punctured with the puncture needle 1 (a), and then the guide wire 3 is inserted into the puncture needle 1. And the guide wire 3 is left in the artery 2 and the puncture needle 1 is removed (b).

Next, a dilator 4 is attached to the outer circumference of the guide wire 3, and the distal end of the dilator 4 is slid along the guide wire 3 and pushed into the artery 2 (c). When the dilation is completed, the dilator 4 is removed (d), and then the catheter 5 is slid along the outer circumference of the guide wire 3 (e), and the catheter 5 is inserted into the artery 2 (f). ).

When the catheter 5 is inserted to a predetermined position in the artery 2, the guide wire 3 is pulled out, and then a medicinal solution such as a contrast agent is administered to the artery 2 through the catheter 5, and a fluoroscopic camera is used. Etc.

As described above, when the catheter 5 is inserted, the guide wire 3 for guiding the catheter 5 is used. The catheter 5 is used for the blood vessel inspection as described above.
It is used not only for treatment but also for examination and treatment of all tubular organs of the human body such as the ureter and the trachea.

As the medical guide wire used for the above-mentioned applications, a thin wire made of a metal such as stainless steel or a shape memory alloy is coiled to have flexibility, and a wire made of the above-mentioned metal. Various types have been proposed, such as a core wire covered with a synthetic resin film or the like. The operability of the guide wire is often influenced by the flexibility of the distal end portion.

As one of such guide wires, Japanese Patent Laid-Open No. 61-106173 discloses a shape memory alloy (TiN).
A guide wire has been proposed in which the tip end portion of a core wire made of i alloy) is thinned and the outer circumference is covered with a synthetic resin film. This guide wire is characterized in that it has flexibility due to the superelasticity of the shape memory alloy, and that the tip of the core wire is thin and the tip is more flexible.

When inserting a guide wire into a blood vessel or a trachea, since these are branched at some places, it is necessary to guide the distal end of the guide wire into the target tube at the branch point. This operation is performed by rotating the base portion of the guide wire at a desired angle and inserting the distal end of the guide wire in a desired direction. Therefore, before inserting the guide wire, the distal end of the guide wire is appropriately shaped (curved) on the spot according to the affected part of the patient.

However, when the core wire is formed of a shape memory alloy as described above, even if the tip end portion is made thin and has flexibility, it is not plastically deformed due to the superelasticity of the shape memory alloy and the tip end portion has a desired shape. The shape could not be shaped.

In order to solve the above problems, the applicant of the present invention, No. 3-24144 and No. 108
No. 555 discloses a guide wire for a catheter in which a tip portion of a core wire made of a shape memory alloy is thinly formed to a predetermined length and the tip portion is easily shaped. The guide wire disclosed in Japanese Utility Model Laid-Open No. 3-24144 is one in which the entire tip portion of the thinly formed core wire is heat-treated to facilitate shaping, and the guide wire disclosed in Japanese Utility Model Laid-Open No. 4-108555 is This is a physical property in which it is easy to partially shape the middle of the tip of the thin core wire.

[0012]

However, in the guide wires disclosed in Japanese Utility Model Laid-Open Nos. 3-24144 and 4-108555, although the tip of the core wire is easily shaped, a shape memory alloy is formed by heat treatment or the like. However, there is a problem that the superelasticity of the above is impaired, the rigidity of the treated portion is increased, and the flexibility of the tip portion is impaired.

Further, since the whole or part of the tip of the core wire made of a shape memory alloy must be heat-treated strictly at a predetermined temperature and time, it is difficult to set and manage heat-treatment conditions and the like, and the manufacturing is complicated. There was a problem.

Therefore, an object of the present invention is to provide a medical device which has supple elasticity as a whole, does not impair the flexibility of the tip portion, is easy to shape the tip portion, has excellent operability, and is easy to manufacture. To provide a guide wire for use.

[0015]

In order to achieve the above object, the medical guide wire of the present invention is a medical guide wire in which a synthetic resin film is coated on the outer periphery of a core wire made of a superelastic material. Is characterized in that its tip is formed thin to a predetermined length, and the synthetic resin film covering at least the tip of the core wire is a shape memory resin film.

In a preferred embodiment of the present invention,
The outer periphery of the synthetic resin film is further covered with a hydrophilic resin film.

[0017]

The shape memory resin has a physical property as hard as a resin at a temperature below the glass transition point, but has a property of softening like a rubber and returning to a memorized shape at a temperature above the glass transition point. are doing. On the other hand, the core wire made of a shape memory alloy is formed so that its tip portion is thinned by a predetermined length, so that the tip portion is not so strong in rigidity and is given sufficient flexibility. Therefore, the shape memory resin film covering the distal end portion of the guide wire can be made more rigid than the distal end portion of the core wire at a temperature below the glass transition point.

Therefore, the tip portion of the guide wire is heated to a temperature not lower than the glass transition point of the shape memory resin, shaped into a desired shape in that state, and maintained at that shape or lower, and then equal to or lower than the glass transition point of the shape memory resin. When cooled to the temperature of 3, the shape memory resin film is solidified in the above-mentioned shape and is given more rigidity than the tip portion of the core wire, so that the tip portion of the guide wire can be maintained in that shape. Therefore, the distal end portion of the guide wire can be easily shaped according to the affected area of the patient so that the tip portion of the guide wire can be easily guided to a target tube at a branch point such as a blood vessel or a trachea, and the operability of the guide wire is improved.

Further, since it is not necessary to apply a treatment such as heat treatment to the physical properties of the core wire made of a superelastic material, the superelasticity of the core wire is not impaired, and the elasticity is generally flexible. And the flexibility of the tip is maintained. In addition, the synthetic resin film coated on the outer periphery of the core wire, when inserted into tubular organs such as blood vessels, ureters, trachea,
Make the slip better.

Furthermore, the guide wire of the present invention can be manufactured by merely covering the outer periphery of the core wire with a synthetic resin film having a shape memory resin film at least at the tip end thereof, and heat treatment or the like requiring strict temperature control. Since it is not necessary, it is easy to manufacture and the quality variation in individual products is reduced.

In a preferred embodiment of the present invention,
By further coating the outer periphery of the synthetic resin film with the hydrophilic resin film, the lubricity with respect to the inner wall of the catheter is improved and the operability is further improved.

[0022]

FIG. 1 shows an embodiment of a medical guide wire according to the present invention. This guide wire 11 is
It is composed of a core wire 12 made of a super elastic material and a synthetic resin film 13 covering the outer circumference thereof. Further, the tip portion 12a of the core wire 12 is formed in a tapered thin shape.

As the superelastic material of the core wire 12, TiNi is used.
Shape memory alloys such as alloys are preferably used. Core wire 12
The wire can be manufactured by, for example, forming a shape memory alloy into a wire shape, putting the wire in a heating furnace, and stretching the wire until it has a desired thickness. Thereby, the shape of the wire is memorized so as to have a predetermined transformation point. The core wire 12 is
In order to obtain supple superelasticity at least under body temperature, it is preferable to set the transformation point of the shape memory alloy to the body temperature or lower.

Then, this wire is cut into a desired length,
The tip is tapered. Such processing can be performed by a method such as etching by dipping the tip in an etching solution and gradually pulling it up, or by a mechanical processing method such as cutting and polishing, swaging, or rolling.

The thickness of the tip portion 12a of the core wire 12 is
0.03 to 0.1 mm is preferable, and the thickness of the core wire 12 other than the tip portion 12a is preferably 0.2 to 0.5 mm. Further, the length of the tip portion 12a of the core wire 12 is preferably 50 to 600 mm.

The synthetic resin film 13 covering the core wire 12 is entirely a shape memory resin film in this embodiment. However, it is possible to form the shape memory resin film at least at the outer periphery of the tip portion 12a of the core wire 12. For example, the tip portion 12a of the core wire 12
The outer periphery of the portion other than may be a synthetic resin film other than the shape memory resin film.

Known shape memory resins include, for example, trinorbornene (manufactured by Nippon Zeon Co., Ltd.), styrene butadiene copolymer (manufactured by Asahi Chemical Industry Co., Ltd.), polyurethane (manufactured by Mitsubishi Heavy Industries Ltd.), etc. Of these, those having a glass transition temperature higher than body temperature are preferably used in the invention. Further, as the synthetic resin other than the shape memory resin, which is coated on the outer periphery of the portion of the core wire 12 excluding the tip portion 12a, various resins such as silicone resin, fluororesin, polyethylene resin, hydrophilic resin, etc. may be used. Used.

The synthetic resin film 13 is made of, for example, a resin core wire 1
It can be formed by a method of coating it on the core wire 2, covering the core wire 12 with a resin tube for heat shrinkage, or molding the resin integrally with the core wire 12. The thickness of the synthetic resin film 13 is not particularly limited, but the thickness of the tip portion 12a of the core wire 12 is higher than that of the tip portion 12a of the core wire 12 at a temperature below the glass transition point of the shape memory resin. , Preferably 5 to 50 μm, and the core wire 1
The portion other than the tip portion 12a of 2 has a thickness that does not adversely affect the flexibility of the core wire 12, preferably 5 to 20 μm. The tip of the synthetic resin film 13 that covers the tip of the core wire 12 is preferably formed into a round shape.

Further, it is preferable that the outer periphery of the synthetic resin film 13 is further covered with a hydrophilic resin film, since the inner wall of the catheter is better lubricated when the catheter is inserted. As such a hydrophilic resin film, for example, the resin disclosed in Japanese Patent Publication No. 4-14991 can be cited.

Next, the operation of the guide wire 11 will be described. In FIG. 4, the core wire 12 at the tip of the guide wire 11 and the temperature and load (rigidity) of the shape memory resin film coated on the outer circumference thereof are shown. The relationship is shown. FIG.
In the above, SMA represents the characteristics of the tip portion 12a of the core wire 12 made of a shape memory alloy, and SMP represents the characteristics of the shape memory resin film coated on the tip portion 12a of the core wire 12.

As described above, the shape memory alloy has a characteristic that the rigidity is low at a low temperature and the rigidity is rapidly increased when the temperature exceeds the transformation point A and becomes a high temperature. Further, the shape memory resin has a characteristic that the rigidity is high at a low temperature and the rigidity becomes low at a temperature higher than the glass transition point B. Therefore, the rigidity of the core wire 12 of the shape memory alloy becomes higher at a temperature higher than the glass transition point B, and the rigidity of the shape memory resin film becomes higher at a temperature lower than the glass transition point B. Has become.

Therefore, at least the tip portion of the guide wire 11 is heated to a temperature higher than the glass transition point B of the shape memory resin, and in that state, the guide wire 11 is shaped into a desired shape and the shape is maintained. When cooled to a temperature lower than the glass transition point B of the shape memory resin as it is, the guide wire 1
At the tip portion of No. 1, the shape memory resin film covering the core wire 12 has higher rigidity than the core wire 12, and the above-described shaped shape is maintained. In this way, the distal end portion of the guide wire 11 can be shaped into a desired shape.

In the present invention, the transformation point A of the shape memory alloy is preferably 35 to 40 ° C., and the glass transition point B of the shape memory resin is preferably 50 to 80 ° C.

FIG. 2 shows another embodiment of the medical guide wire according to the present invention. This guide wire 21
Is a core wire 22 made of a shape memory alloy as in the above embodiment.
And a synthetic resin film 23 made of a shape memory resin that covers the outer periphery thereof. However, in this embodiment, the distal end portion 22a of the core wire 22 forms a step portion 22b and has a reduced diameter.

In this guide wire 21 as well, the distal end portion 22a of the core wire 22 is formed thin and the synthetic resin film 23 covering the outer periphery thereof is made of a shape memory resin, so that the distal end portion of the guide wire 21 is easily shaped. To be done.

FIG. 3 shows still another embodiment of the medical guide wire according to the present invention. The guide wire 31 is formed by using two core wires 32 and 33 made of a shape memory alloy, and extending the tip 33a of one of the core wires 33 to thin the tip of the whole core wire. Further, the two core wires 32 and 33 are bundled and their outer circumferences are covered with a synthetic resin film 34 made of a shape memory resin.

This guide wire 31 also has core wires 32 and 33.
Since the distal end portion 33a of the guide wire 31 is formed thin and the synthetic resin film 34 covering the outer periphery thereof is made of a shape memory resin, the distal end portion of the guide wire 31 is easily shaped.

As described above, various structures can be adopted as the structure for thinning the tip of the core wire. The core wire may be a round wire or a square wire, but a round wire is most preferable in order to make it easy to bend uniformly in all directions.

Next, the method of using the guide wire of the present invention will be described by taking the guide wire 11 for catheter shown in FIG. 1 as an example. For example, as shown in FIG. When the resin film is heated to a temperature equal to or higher than the glass transition point, wound around the cored bar 44 and cooled to a temperature equal to or lower than the glass transition point while maintaining the state, as shown in FIG. The part can be shaped into a curved arc. Thus, by shaping the shape of the distal end portion, the guide wire 11 can be easily inserted.

That is, FIG. 7 shows a state in which the guide wire is guided to the blood vessel. Here, the blood vessel 45 into which the guide wire 11 is inserted has its distal end branched into branch pipes 46 and 47, and the distal end of the branch pipe 47 further branches into branch pipes 48 and 49. Then, when the target inspection or treatment site is in the branch tube 49, the distal end of the guide wire 11 is moved along the arrow in the figure by shaping the distal end of the guide wire 11 as shown in the figure. Therefore, it can be easily guided to the target branch pipe 49.

[0041]

As described above, according to the present invention, at least the outer periphery of the tip of the core wire is covered with the shape memory resin film, so that the tip of the guide wire is formed into a desired shape according to the application site of the patient. It can be shaped. Since the tip portion of the core made of a superelastic material does not need to be treated to change its physical properties, the flexibility of the tip portion is not impaired. Therefore, the medical guide wire having supple elasticity as a whole, excellent flexibility of the distal end portion, and moreover, the distal end portion can be easily shaped, thereby providing excellent medical operability and easy to manufacture. be able to.

[Brief description of drawings]

FIG. 1 is a partial sectional view showing an embodiment of a medical guide wire according to the present invention.

FIG. 2 is a partial cross-sectional view showing another embodiment of the medical guide wire according to the present invention.

FIG. 3 is a partial cross-sectional view showing still another embodiment of the medical guide wire according to the present invention.

FIG. 4 is a chart showing a relationship between temperature and load of a shape memory alloy and a shape memory resin.

FIG. 5 is a partial side view showing a state in which the distal end portion of the guide wire is shaped.

FIG. 6 is a partial side view showing the distal end of the guide wire shaped as described above.

FIG. 7 is an explanatory diagram showing a state in which a guide wire is guided to a branch vessel of a branched blood vessel.

FIG. 8 is an explanatory view showing a catheter insertion procedure.

[Explanation of reference numerals] 11, 21, 31 Medical guide wire 12, 22, 32, 33 Core wire 12a, 22a, 33a Tip of core wire 13, 23, 34 Synthetic resin film

Claims (2)

[Claims] 1. A medical guidewire comprising a core wire made of a superelastic material and a synthetic resin film coated on the outer periphery of the core wire. A medical guide wire characterized in that the synthetic resin film covering the portion is a shape memory resin film. 2. The medical guide wire according to claim 1, wherein the outer periphery of the synthetic resin film is further covered with a hydrophilic resin film.