JP2002095755A - Medical guidewire - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide excellent elasticity at the distal end, easily follow the inside of a body cavity having a strong bending portion, and deform the distal end so that it can be restored. Provided is a medical guidewire which is excellent and can be easily bent at the distal end. SOLUTION: A core wire 4 having a main core part 5 and a tip core part 7 having an average outer diameter smaller than the average outer diameter of the main core part 5 and usually made of metal, And a tip-side superelastic coating layer 6 made of superelastic metal and covering at least a part of the outer periphery of the medical guidewire.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a medical guidewire for guiding a medical device such as a catheter used for treatment or examination to a predetermined position in a body cavity such as a blood vessel.

[0002]

2. Description of the Related Art In some cases, a catheter must be inserted to a predetermined position in a blood vessel for treatment or examination.
A catheter is generally excellent in flexibility, and it is difficult to push a catheter alone to a predetermined position inside a blood vessel. Therefore, it is common practice to insert a guide wire into a blood vessel in advance and guide the catheter to a predetermined position in the blood vessel along the guide wire.

[0003] A guide wire must be inserted into a tortuous blood vessel so as not to damage the inner wall of the blood vessel. When the tip of the guide wire is located in an arterial blood vessel near the heart, the tip of the guide wire is
In many cases, a portion that is bent to R = 20 mm or less is passed. In this case, if permanent deformation is caused, it is difficult to feed the material beyond that. Therefore, the guide wire is
In particular, it is important that the tip portion has excellent flexibility.

Therefore, as a conventional guide wire, the outer diameter of the guide wire at the distal end portion is made smaller than that of the other portions, and a coil spring is mounted on the outer periphery of the distal end portion to improve the flexibility of the distal end portion. A guide wire aiming at the above has been proposed.

[0005]

However, in such a conventional guide wire, since the guide wire and the coil spring are made of stainless steel, the elasticity of the distal end portion is not sufficient, and a strong bending of R = 20 mm or less is required. However, there is a problem in its followability when inserting into a blood vessel having the following.

It has also been proposed that the guide wire be made of a superelastic metal such as a nickel-titanium alloy in order to improve elasticity. However, if the entire guide wire is made of a superelastic metal, the elasticity of the distal end portion is improved and the followability to the bend is improved, but the guide wire can be easily bent even to the proximal end portion, and the guide wire is inserted into the blood vessel. There is a problem in the indentation characteristics at the time of indentation.

In order to solve these problems, there has been proposed a guide wire in which the base end of a guide wire is made of stainless steel and the distal end is made of a superelastic metal. However, it is difficult to join the stainless metal and the superelastic metal, the joining tends to be insufficient, and the strength at the joint becomes a problem. Further, depending on the condition of the blood vessel of the patient using the guide wire, it is necessary to bend the shape of the distal end portion of the guide wire into a substantially arc shape or an L shape in advance. However, since superelastic metal is difficult to be plastically deformed, Difficult to tune.

The present invention has been made in view of such circumstances, has excellent elasticity at the distal end, and easily follows the inside of a body cavity having a strongly bent portion, whereby the distal end is deformably deformed,
Moreover, it is an object of the present invention to provide a medical guidewire which has excellent pushing characteristics into a body cavity and which can be easily bent at the distal end.

[0009]

In order to achieve the above object, a medical guide wire according to the present invention comprises a main core portion and a tip core having an average outer diameter smaller than the average outer diameter of the main core portion. A core wire having a material portion and usually made of metal, and a tip-side superelastic coating layer that covers at least a part of the outer periphery of the tip core material portion and is made of superelastic metal.

In the middle of the main core portion, a small-diameter core portion having an average outer diameter smaller than the average outer diameter of the main core portion is formed. Alternatively, an intermediate superelastic coating layer made of a superelastic metal may be formed.

The method for forming the super-elastic coating layer on the outer peripheral surface of the core portion is not particularly limited, and examples thereof include a vapor deposition method and a sputtering method. The method is preferred.

The medical guidewire of the present invention preferably has an outer peripheral surface integrally coated with a nonmetallic biocompatible coating film. Examples of the biocompatible coating film include ordinary polymers used for medical purposes such as olefins such as polyethylene, nitrogen-containing polymers such as polyimide and polyamide, and siloxane polymers. Further, the coating film is not limited to a polymer, and may be an inorganic coating film such as carbon such as silicon carbide, pyrolite carbon, or diamond-like carbon, but is preferably a non-metallic film. That is, in the case of a non-metallic biocompatible coating film, the possibility of metal allergy due to elution of ions and the like is caused, and a potential difference is caused by contact of dissimilar metals, so that corrosion in a living body is often accelerated. is there. The thickness of the biocompatible coating film is not particularly limited, but is preferably 0.01 to 10 μm, and more preferably 0.2 to 0.6 μm. In the present invention, the entire outer surface of the guide wire may be covered with a plating film or the like in which metal ions such as gold and platinum are hardly eluted, and the outer surface of the plating film may be covered with a biocompatible coating film. Is also good.

On the outer periphery of the tip side superelastic coating layer or the biocompatible coating film formed on the tip core portion,
Preferably, a coil spring is mounted along the axial direction.

In the present invention, the core wire is usually made of a metal. In the present invention, the normal metal means a metal other than the superelastic metal. Preferred normal metals are preferably plastically deformable metals such as stainless steel, gold, platinum, aluminum, steel, tungsten, tantalum or alloys thereof. Examples of the superelastic metal include nickel-titanium, iron-manganese-silicon, copper-aluminum-nickel, and amorphous metal. Note that, in the present invention, superelasticity means that a recoverable elastic strain range is large,
For example, say 1% to 10%
It also includes pseudoelasticity that causes twinning deformation and large elasticity of amorphous. In general, a superelastic metal has an elastic modulus in a superelastic region that is extremely small as compared with that of iron or stainless steel, and is excellent in flexibility.

[0015]

In the medical guidewire according to the present invention, the core material at the distal end of the core wire is coated with a superelastic metal, so that it has excellent elasticity at the distal end and can be easily inserted into a body cavity having a strongly bent portion. The tip portion is deformed to be recoverable. In addition, since the base end of the core wire is made of a main core material and is usually made of a metal such as stainless steel, the operating force of the base end of the guide wire is transmitted well to the tip of the wire and pushed. Excellent characteristics.

Further, in the present invention, the distal end of the guide wire has not only a superelastic metal but also a distal end core portion usually made of a metal. Depending on the application of the guidewire, it is necessary to bend the shape of the distal end portion of the guidewire into a substantially arc shape in advance, but in the present invention, since the distal end core portion is usually formed of metal,
Bending by plastic deformation is easy. Furthermore, in the present invention, since the structure is not such that the main core portion made of metal and the core portion made of super-elastic metal are joined, the strength of the joint does not matter.

In the middle of the main core portion, a small-diameter core portion having an average outer diameter smaller than the average outer diameter of the main core portion, and an intermediate superelastic coating layer made of a superelastic metal are formed. In the guidewire according to the present invention, a guidewire having excellent flexibility can be realized even in the middle of the main core portion. In a body cavity into which a guidewire is inserted, a strongly bent portion is not always located at the distal end portion of the guidewire, and a strong bent portion may be present even at the base end portion of the guidewire. This guidewire can be suitably used as a guidewire to be inserted into such a body cavity.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments shown in the drawings. FIG. 1 is a schematic sectional view of a medical guidewire according to one embodiment of the present invention, FIG. 2 is a schematic view showing an example of use of the guidewire shown in FIG. 1, and FIGS. 3 and 4 are other embodiments of the present invention. 1 is a schematic sectional view of a guide wire according to FIG.

First Embodiment As shown in FIG. 1, a medical guidewire 2 according to an embodiment of the present invention comprises a main core portion 5 and a main core portion 5.
Has a core wire 4 having a tip core portion 7 having an average outer diameter smaller than the average outer diameter. Main core part 5 of core wire 4
The tip core portion 7 is integrally formed of a wire having a substantially circular cross section. The material of the core wire 4 is not particularly limited, but may be stainless steel (for example, SUS31).
6), metals such as gold, platinum, aluminum, tungsten, tantalum or alloys thereof.

The total length L1 of the core wire 4 varies depending on the purpose of use and is not particularly limited.
It is about 350 cm, and the core material portion 7 of the core wire 4
Is, for example, about 5 to 50 cm. The outer diameter of the main core material portion 5 of the core wire 4 may be uniform along the axial direction, or may be tapered toward the distal end. The average outer diameter of the main core portion 5 is not particularly limited, but is about 0.15 to 0.90 mm. Also, the outer diameter of the tip core portion 7 may be uniform along the axial direction,
It may be tapered toward the tip. The average outer diameter of the tip core portion 7 is not particularly limited, but is preferably about 1/5 to 1/2 of the average outer diameter of the main core portion 5.

A spherical or hemispherical ball portion 10 is joined to the distal end of the core portion 7 of the core wire 4. The ball portion 10 smoothes the distal end portion of the guide wire 2,
When the guide wire 2 is inserted into a body cavity such as a blood vessel, the guide wire 2 is a portion for preventing damage to the inner wall of the body cavity as much as possible. The ball portion 10 is made of, for example, a metal such as platinum or gold, and is joined to the tip of the tip core portion 7 by means such as welding. The outer diameter of the ball portion 10 is preferably about 0.5 to 2 times the average outer diameter of the main core portion 5.

The outer periphery of the tip core portion 7 is covered with a tip-side superelastic coating layer 6 made of superelastic metal. The coating layer 6 is made of a superelastic metal such as a nickel-titanium alloy. A superelastic metal has a large recoverable elastic strain range, for example, as high as 1% to 10%.
It has the property that the force required for deformation is substantially constant even when the strain increases. In general, a superelastic metal has an extremely small stress in the superelastic region as compared with the elastic modulus of iron or stainless steel, and is excellent in flexibility. Therefore, the distal end portion of the guide wire 2 covered with the coating layer 6 has a property of recovering the original shape after the stress is removed.

The thickness of the coating layer 6 is not particularly limited.
The thickness is about 1 to 100 μm, and by adjusting this thickness, the superelastic property of the distal end portion of the guide wire 2 can be adjusted. Although the coating layer 6 can be formed by a sputtering method, it is particularly preferable to use magnetron sputtering.

The outer peripheral surface of the guide wire 2 is integrally covered with a biocompatible coating film 8. The biocompatible coating film is not particularly limited, for example, olefins such as polyethylene, nitrogen-containing polymers such as polyimide and polyamide, siloxane polymers, and the like.
An ordinary polymer or the like used for medical purposes is used. Further, the coating film is not limited to the polymer, and may be an inorganic coating film such as silicon carbide, carbon such as pyrolite carbon and diamond-like carbon.

In the medical guide wire 2 according to the present embodiment, the core material portion 7 of the core wire 4 is covered with the coating layer 6 made of superelastic metal, so that the elasticity at the distal end portion is excellent. . Therefore, as shown in FIG. 2, in the case where the guide wire 2 is inserted from the aorta 22 at the base of the foot to the coronary artery of the heart 20, an intravascular having a strongly bent portion near the distal end of the wire is used. The wire tip easily deforms so that the wire tip can be restored. Further, the base end of the core wire 4 constituting the guide wire 2 is composed of the main core material portion 5 and is made of a normal metal such as stainless steel. It transmits well to the tip and has excellent pushing characteristics. Note that a coating layer made of a superelastic metal may be provided on the main core portion at the base end within a range that does not affect the insertion characteristics.

In the present embodiment, the distal end portion of the guide wire 2 is not made of only the superelastic metal, but has a tip core portion 7 usually made of metal. In the present embodiment, the outer periphery of the tip core portion is covered with a coating layer made of a superelastic metal. However, the covering portion does not need to be the entire outer periphery, and may be part of the outer periphery as long as flexibility can be obtained. May be coated. Depending on the application of the guide wire 2, it is necessary to bend the shape of the distal end portion of the guide wire 2 into a substantially arc shape in advance. In the present embodiment, the guide wire 2 has the distal end core portion 7 usually made of metal. Therefore, bending by plastic deformation is easy. Further, in the present embodiment, since the structure is not such that the main core portion made of a normal metal and the tip core portion made of a superelastic metal are joined, the strength of the joint does not matter.

Second Embodiment As shown in FIG. 3, a medical guidewire 2a according to the present embodiment is a modification of the guidewire 2 shown in FIG.
The common portions are denoted by the same reference numerals, and the description thereof will be partially omitted. In the guide wire 2a according to the present embodiment, a coil spring 12 is mounted along the axial direction on the outer periphery of the distal-side superelastic coating layer 6 and the biocompatible coating film formed on the distal-end core portion 7. Coil spring 1
The material of No. 2 is the same as the material of the core wire 4 and is made of, for example, stainless steel. Further, a part of the coil spring can be made of a metal having a high X-ray absorbing property such as platinum.

In the guide wire 2a according to the present embodiment,
By attaching the coil spring 12 to the distal end of the wire 2a, the range of elasticity adjustment at the distal end of the wire is widened, and the outer diameter becomes closer to the main core portion, so that the catheter can be easily slid. Other functions and effects of the guide wire 2a of the present embodiment are the same as those of the guide wire 2 shown in FIG.

Third Embodiment As shown in FIG. 4, a medical guide wire 2b according to this embodiment is a modification of the guide wire 2 shown in FIG.
The common portions are denoted by the same reference numerals, and the description thereof will be partially omitted. In the guide wire 2b according to the present embodiment, the small-diameter core portion 7 having an average outer diameter smaller than the average outer diameter of the main core portion 5b is provided in the middle of the main core portion 5b of the core wire 4b.
b is formed, and an intermediate superelastic coating layer 6b made of superelastic metal is formed on the outer periphery of the small-diameter core material portion 7b. The configuration of the distal end portion of the guide wire 2b is exactly the same as the guide wire 2 shown in FIG.

The outer diameter of the small diameter core portion 7b is
Provided that it is smaller than the average outer diameter of b, it may be substantially the same as the outer diameter of the tip core portion 7, but may be somewhat larger. The outer diameter of the small-diameter core part 7b is preferably about 0.1 to 0.8 times the maximum outer diameter of the main core part 5b.

The formation position and the axial length of the small diameter core portion 7b are determined by the purpose of use of the guide wire 2b and are not particularly limited. As an example, a small-diameter core material portion 7b
Is a length L3 = 200 from the base end of the wire 2b.
And a length L4 in the axial direction is, for example, about 200 to 500 mm.

The thickness of the intermediate superelastic coating layer 6b is not particularly limited, but is about 10 to 200 μm. By adjusting this thickness, it is possible to adjust the superelastic properties of the middle part of the guide wire 2b on the base end side. Can be. Coating layer 6b
Is made of the same superelastic metal as the superelastic metal constituting the tip side superelastic coating layer 6.

In the guide wire 2b according to the present embodiment,
In the middle of the main core portion 5b, a small-diameter core portion 7b having an average outer diameter smaller than the average outer diameter of the main core portion 5b and an intermediate superelastic coating layer 6b made of a superelastic metal are formed. I have. Therefore, in the guide wire 2b according to the present embodiment, the guide wire 2b having excellent flexibility can be realized even in the middle of the main core portion 5b.

As shown in FIG. 2, in a body cavity such as a blood vessel into which a guide wire is inserted, a strongly bent portion is not always located only at the distal end portion of the guide wire, and also at the base end portion of the guide wire. There may be a bend. The guide wire 2b can be suitably used as a guide wire to be inserted into such a body cavity. Other functions and effects of the guide wire 2b of the present embodiment are the same as those of the guide wire 2 shown in FIG.

It should be noted that the present invention is not limited to the above-described embodiment, but can be variously modified within the scope of the present invention.

[0036]

As described above, according to the present invention, the distal end portion has excellent elasticity at the distal end portion, easily follows the inside of a body cavity having a strongly bent portion, and is deformed so that it can be restored.
In addition, it is possible to provide a medical guide wire that has excellent pushing characteristics into a body cavity and that can be easily bent at the distal end.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a medical guidewire according to an embodiment of the present invention.

FIG. 2 is a schematic view showing an example of use of the guide wire shown in FIG.

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

FIG. 4 is a schematic sectional view of a guide wire according to another embodiment of the present invention.

[Explanation of symbols]

 2, 2a, 2b: Medical guide wire 4, 4b: Core wire 5: Main core portion 6: Tip-side superelastic coating layer 7: Tip core portion 8: Biocompatible coating film 12: Coil spring

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Seiji Shimura 2-28-506 Minamicho, Toda City, Saitama F-term (reference) 4C167 AA28 BB02 BB03 BB06 BB13 BB14 BB38 CC08 CC19 FF03 GG03 GG06 GG07 GG09 GG21 GG22 GG23 GG24 GG26 GG33 GG42 HH08 HH17

Claims (3)

[Claims] 1. A core wire having a main core portion and a tip core portion having an average outer diameter smaller than the average outer diameter of the main core portion, which is usually made of metal, and an outer periphery of the tip core portion. And a distal-side super-elastic coating layer made of super-elastic metal and covering at least a part of the medical guide wire. 2. A small-diameter core part having an average outer diameter smaller than the average outer diameter of the main core part is formed in the middle of the main core part, and an outer periphery of the small-diameter core part is formed. 2. The medical guidewire according to claim 1, wherein an intermediate superelastic coating layer made of a superelastic metal is formed on the medical guidewire. 3. The medical guidewire according to claim 1, wherein the outer peripheral surface is integrally coated with a biocompatible nonmetallic coating film.