JPH07227429A - Guide wire for medical treatment - Google Patents

Abstract

PURPOSE:To provide a guide wire which has excellent resilience at its front end part and is safely insertable into the vascular organs without damaging their tissues. CONSTITUTION:This guide wire 11 is constituted by finely forming the front end 13 of a core wire 12, mounting a coil 17 at the outer periphery of the front end 13, fixing the base end of the coil 17 to the middle of the core wire 12 and fixing the front end of the coil 17 together with the front end 14 of the core wire 12 to a round head part 16. A wire which is finely formed to the diameter gradually decreased toward the front end is used as the coil 17. The coil 17 may consist of the round wire or the wire having a modified cross section exclusive of the round wire.

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, ureter, bile duct, trachea or the like.

[0002]

2. Description of the Related Art In recent years, for examination and treatment of tubular organs of the human body such as blood vessels, ureters, bile ducts, trachea, etc., a catheter is inserted to administer a drug such as a contrast agent, or tissue is inserted through the catheter with forceps or the like. It is being done to collect a part of. When inserting the catheter,
A relatively thin and flexible guide wire is first inserted into the tubular organ, a catheter is inserted along the outer circumference of the guide wire, and then the guide wire is extracted.

Examples of the guide wire include (1)
A core wire made of stainless steel, shape memory alloy, etc. is formed in a tapered shape and the outer periphery is covered with a synthetic resin film. (2) A coil in which a thin wire is closely wound is fixed to the tip end of a relatively thick core wire. (3) Various ones have been proposed, such as one in which a safety wire and an inner core wire are inserted into the coil of close winding, and the ends of these wires are fixed to the coil.

In FIG. 4, as an example, the guide wire 31 disclosed in Japanese Utility Model Laid-Open No. 3-122849 by the present applicant is disclosed.
It is shown. That is, the guide wire 31 is brazed to the tapered distal end portion 35 of the metal wire 32 at one end of a metal coil 37 having substantially the same diameter.
The other end of 7 is fixed to the curved head 36 by brazing. Further, a metal mesh 33 is arranged in the metal coil 37, one end of which is fixed to the tip portion 35 of the wire 32, and the other end 34 is fixed to the head portion 36.

As another example, FIG. 5 shows a guide wire 41 described in Japanese Patent Application No. 4-65422 by the present applicant. That is, this guide wire 41
The core wire 42 is composed of a plurality of thin metal wire strands,
The tip end portion of the core wire 42 forms a reduced diameter portion 43 via a taper portion 45. A coil 47 of a shape memory alloy is arranged on the outer periphery of the tapered portion 45 and the reduced diameter portion 43 of the core wire 42. The coil 47 is fixed to the head portion 46 together with the tip end 44 of the core wire 42 and the base thereof. The end is the tapered portion 45 of the core wire 42.
The metal brazing material 48 is fixed to the above.

[0006]

Since such a guide wire is to be inserted into a curved path such as a blood vessel, the distal end of the guide wire is required to have sufficient flexibility so as not to damage the tissue. Requires a certain degree of rigidity so that the operation at hand can be transmitted. Further, at a branched or bent portion such as a blood vessel, it is necessary to direct the distal end portion of the guide wire in a desired direction and guide it properly in the traveling direction. In this case, rotate the guide wire at a hand portion in a predetermined direction. The guide wire tip is directed in a desired direction. For this reason, the guide wire is also required to have a rotation transmissibility to transmit the rotational force at hand to the distal end portion.

However, in the guide wires shown in FIGS. 4 and 5, the flexibility of the coil attached to the distal end portion of the core wire is not sufficient, so there is a risk of accidentally piercing the tubular organ during insertion. . In order to increase the flexibility of the coil, it is conceivable to reduce the coil wire diameter or open the coil pitch to lower the initial tension, but there is a limit to strength in reducing the coil wire diameter. , If the coil pitch is opened too much, there is a possibility of coil displacement.

[0008] Therefore, an object of the present invention is to obtain a sufficient flexibility of the distal end portion without impairing the operability from the proximal side, and to ensure safe insertion even when inserting into a large bent portion of a tubular organ. The purpose of the present invention is to provide a medical guide wire.

[0009]

In order to achieve the above object, a medical guide wire according to the present invention is provided with a core wire whose distal end portion is thin and a distal end portion of the core wire, and In the middle of the core wire, a medical guide wire comprising a coil having a tip fixed to a round head together with the tip of the core wire, wherein the coil is a metal gradually thinned toward the tip. It is characterized in that it is composed of a wire rod.

According to a preferred aspect of the present invention, the coil is formed of a round wire having a circular cross section.

According to another preferred aspect of the present invention, the coil is formed by a wire having an irregular cross section whose cross-sectional shape is other than circular.

[0012]

In the medical guide wire according to the present invention, the tip end of the core wire is formed thin, and the coil attached to the outer periphery of the tip end of the core wire is made of a metal wire material which is gradually thinned toward the tip. Because of the construction, the tip has excellent flexibility, eliminating the risk of damaging or piercing tissue when inserted into a bent tubular organ.

Further, since the coil mounted on the outer circumference of the tip of the core wire is made of a metal wire rod which is gradually thinned toward the tip, the base side of the coil has relatively high rigidity and can be operated from the hand side. Properties, such as rotation transmission, are not significantly impaired.

The cross-sectional shape of the coil may be a round wire or a wire having an irregular cross-section, both of which are excellent because they are tapered toward the tip. Flexibility can be obtained. Further, by combining with the tapered shape of the core wire, it is possible to give the coil portion flexibility.

[0015]

1 is a sectional view showing an embodiment of a medical guide wire according to the present invention, and FIG. 2 is a sectional view showing a shape of a coil used for the guide wire before processing.

The medical guide wire 11 includes a metal core wire 12 and a metal coil 1 fixed to the outer periphery of the tip end portion thereof.
7 and a round head 16 provided at their tips.

The core wire 12 is preferably made of an elastic metal material such as stainless steel, shape memory alloy, or piano wire. Further, the core wire 12 is not limited to one wire and may be a twisted wire in which a plurality of thin wires are twisted together. The tip portion 13 of the core wire 12 is formed in a taper shape or a step shape so as to be gradually thin. The diameter of the core wire 12 is set within a range of about 0.1 to 3 mm so that appropriate elasticity and rigidity can be obtained according to the purpose and the core wire 12 can be easily inserted. Further, the length of the reduced diameter tip portion 13 of the core wire 12 is preferably 30 to 500 mm. The tip of the core wire 12 is fixed to the head 16.

As the coil 17, gold, platinum, tungsten and the like having radiopacity are preferable, but tungsten is particularly preferable in view of polishing processing described later. Further, an elastic metal material such as stainless steel, a shape memory alloy, or a piano wire similar to the core wire 12 may be used. In that case, after the polishing processing described later is performed, the surface thereof is made of gold, platinum, tungsten, or the like. It is preferable to form a film of an X-ray opaque substance by a method such as plating, ion plating, sputtering, vapor deposition, and CVD.

The coil 17 is made of a wire material having the same wire diameter as that of the coil 17a (see FIG. 2) and is processed by means of chemical polishing, electrolytic polishing or the like so that the wire diameter becomes smaller toward the tip. It is formed.

For chemical polishing, for example, when the wire is formed of a stainless wire, an etching solution such as an aqueous solution of ferric chloride is used, and the tip of the coil is dipped in this solution and the coil gradually increases with time. Can be done by pulling up.

For electrolytic polishing, for example, when the wire material is a stainless steel material, a mixed solution of phosphoric acid, sulfuric acid, chromic acid, etc. is used, and the current density is 30 to 100 A / dm ² , and 30 to 10
It is performed by electrolyzing for a minute. Also in this case, the tip of the coil can be immersed in the electrolytic solution and the coil can be pulled up little by little over time.

It is ideal that the tip end wire diameter of the coil 17 is preferably 1/2 or less of the original wire diameter. When the coil 17 is made of a material having no X-ray opacity such as stainless steel, as described above,
It is preferable to form a film made of a radiopaque material.

Further, the outer circumference of the coil 17 may be coated with a synthetic resin coating such as a fluororesin in order to improve the slipperiness of the catheter. Further, the surface of the synthetic resin film may be coated with a hydrophilic polymer. Examples of such a hydrophilic polymer include resins disclosed in Japanese Patent Publication No. 14991/1991.

The coil 17 thus formed is made of metal brazing, plasma welding or the like so that the end with the thicker wire diameter is at the base 15 of the tip portion 13 of the core wire 12, and the end with the thinner wire diameter is as described above. It is fixed to a hemispherical head 16 together with the tip 14 of the core wire 12. The width dimension of the metal brazing is preferably at least 1 mm or more. When the guide wire 11 is inserted into the tubular organ, the head 16 serves to prevent damage to the inner wall of the tubular organ during the insertion.

The coil 17 may be subjected to chemical polishing, electropolishing, etc., after being fixed to the core wire 12 as described above, together with the core wire 12.

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

The guide wire 21 of this embodiment has a core wire 22 having a reduced diameter at its distal end 23, a head portion 26 fixed to a tip end 24 of the core wire 22, and a core wire 22 as in the above embodiment. It is arranged on the outer periphery of the tip portion 23, and the base end is the
The coil 27 is fixed to the base side of the coil and the tip thereof is fixed to the head 26.

The present embodiment is different in that a flat wire having a rectangular cross section is used as the coil 27. In this case, the point that the wire diameter of the coil 27 is processed so as to become smaller toward the tip end is
This is similar to the above embodiment.

The coil used for the medical guide wire of the present invention may be a rectangular wire having a square cross section as shown in FIG. 6 (a), or may be a rectangular wire as shown in FIG. 6 (b). It may be a crushed line whose cross section has a shape obtained by crushing a circle as shown. In this way, it is also possible to use lines of various irregular cross sections having a cross section other than a circular shape.

In the medical guide wires 11 and 21 of the present invention according to each of the above-mentioned embodiments, since the wire diameter of the coil portion is successively formed thinner toward the distal end direction, the flexibility is further improved,
As a result, even a tubular organ with a large number of bends could be safely inserted without damaging the tissue.

[0031]

As described above, according to the present invention,
The wire diameter of the coil is gradually reduced in the distal direction, which further improves flexibility, which facilitates insertion of tubular organs, especially into highly bent organs, and also prevents damage to the organs during insertion. Can be prevented. Also, since the wire diameter of the coil becomes thinner toward the tip,
The outer diameter of the coil itself is also reduced, which facilitates insertion into a tubular organ. Further, as compared with the case where the wire diameter of the entire coil is reduced, the transmissibility of the operation on the proximal side is good and the strength is also excellent.

[Brief description of drawings]

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

FIG. 2 is a cross-sectional view showing a shape of a coil used for the guide wire before processing.

FIG. 3 is a sectional view of an essential part showing another embodiment of the medical guide wire according to the present invention.

FIG. 4 is a sectional view of an essential part showing an example of a conventional guide wire.

FIG. 5 is a cross-sectional view of main parts showing another example of a conventional guide wire.

FIG. 6 is a cross-sectional view showing another example of the coil used in the medical guide wire according to the present invention.

[Explanation of symbols]

 11, 21 Guide wire 12, 22 Core wire 13, 23 Tip part 16, 26 Head part 17, 27 Coil

Claims (3)

[Claims] 1. A core wire having a thin tip, a core wire attached to the outer periphery of the tip of the core wire, a base end of which is fixed in the middle of the core wire, and a tip of the core wire together with the tip of the core wire. A medical guidewire comprising a coil fixed to a portion, wherein the coil is made of a metal wire rod that is gradually thinned toward a tip. 2. The medical guide wire according to claim 1, wherein the coil is formed of a round wire whose cross-sectional shape is circular. 3. The medical guide wire according to claim 1, wherein the coil is formed of a wire having an irregular cross section, the cross section of which has a shape other than a circular shape.