JP4767446B2 - Catheter guide wire and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a guide wire for a catheter, more specifically, a guide wire for a catheter used when a therapeutic or examination catheter is introduced to a required part of a body cavity such as a blood vessel, trachea and digestive tract of a human body , and a method for manufacturing the same. About.
[0002]
[Prior art]
As is well known, when introducing a catheter for treatment or examination into a required part of a body cavity such as a blood vessel, trachea and digestive tract of a human body, a catheter guide wire is introduced to the required part prior to the introduction of the catheter. Yes. A catheter guide wire is generally formed by applying a protective coating made of a synthetic resin to a metal core as required.
[0003]
Therefore, it is important that the guide wire for catheter has the following characteristics. The tip must be sufficiently flexible so that the introduction of the guide wire does not damage the body cavity, and the tip conforms to a shape conforming to advance along the meandering and branching body cavity. It is also important that the material has excellent properties, and therefore, it is important that the elastic modulus of the tip portion is sufficiently small. On the other hand, when the guide wire is introduced, the proximal end portion is operated to control the traveling direction of the distal end portion. Therefore, the proximal end portion must be excellent in motion transmission such as rotation. It is important that the elastic modulus of the base end portion is relatively large. In order to satisfy the characteristics required for a guide wire for a catheter, Japanese Patent Publication No. 3-31472 forms a core from an alloy having superelasticity (that is, a material that undergoes plastic deformation by martensitic transformation). At the same time, it has been proposed that the core is subjected to appropriate different heat treatment along the longitudinal direction of the core.
[0004]
[Problems to be solved by the invention]
However, the catheter guide wire as described above disclosed in Japanese Patent Publication No. 3-31472 is still not fully satisfactory, and has the following problems. That is, by applying different heat treatments along the longitudinal direction of the core, the elastic modulus of each part of the core is kept within the required range, but there is a limit to the adjustment of the elastic modulus by heat treatment, and the elastic modulus of each part It is extremely difficult, if not impossible, to make the desired range. If the elastic modulus of the distal end is made sufficiently small, the elastic modulus of the proximal end will be smaller than the desired range, and if the elastic modulus of the proximal end is made the required range, the elastic modulus of the distal end will be There is a tendency to be larger than the desired range. In addition, a considerably advanced technique is required to perform the heat treatment as required, and therefore the manufacturing cost is considerably high.
[0005]
The present invention has been made in view of the above-mentioned facts, and the main technical problem thereof is that the elastic modulus of the tip portion is sufficiently small even though it can be manufactured without significant increase in manufacturing cost. It is an object of the present invention to provide a new and improved guide wire for a catheter which can cause the elastic modulus of the proximal end portion to fall within a required range.
[0006]
[Means for Solving the Problems]
As a result of diligent research, the present inventor has made the core of the guide wire for the catheter into a so-called two-layer configuration of a center wire having a relatively low elastic modulus and a covering material having a relatively high elastic modulus, and has a base end of a required length. It has been found that the main technical problem can be achieved by changing the interrelationship between the center wire and the covering as required in the part, the intermediate part and the tip part .
[0007]
That is, according to the present invention, as a guide wire for a catheter that achieves the above main technical problems, a center wire formed from an alloy having superelasticity, and coated with the center wire and formed from stainless steel or a copper-based alloy. Consists of a core composed of a covering material and a protective coating made of synthetic resin,
The core at the base end portion having a length of 500 mm or more has a constant outer diameter of 0.5 to 0.8 mm and a constant thickness of 0.05 to 0.4 mm. It consists of a covering material,
The core in the middle part having a length of 50 to 700 mm is composed of the center wire and the covering material having a constant outer diameter of 0.5 to 0.8 mm, and the thickness of the covering material Is gradually reduced from the rearmost end, which is the same thickness as the covering material at the base end, to the leading edge, which is zero,
The core at the tip portion having a length of 100 to 300 mm is composed only of the center wire, and the outer diameter of the center wire is the same as the center wire at the intermediate portion, and the outer diameter is 0 from the rear end. Gradual reduction to the cutting edge of .05 to 0.25mm,
The protective coating covers the entire surface including the proximal end surface and the distal end surface of the core;
The outer diameter of the guide wire is constant over the entire length,
A catheter guide wire is provided.
[0008]
Preferably, the protective coating is mixed with a contrast agent. The tip load when the 0.8mm deflection in three-point bending test at two support points spaced 14mm is not more than 0.6 kgf, the base end three-point bending at the two support points spaced 14mm test It is preferable that the load when the deflection is 0.8 mm is 0.7 kgf or more . A guide wire for a catheter is obtained by covering a central wire formed of a superelastic alloy with a tube-shaped covering material formed of stainless steel or a copper-based alloy, and then extending the covering material in the length direction. It can be conveniently produced by firmly bonding the covering material to the central wire, and then grinding the required portions of the covering material and the central wire, and then applying a protective coating made of synthetic resin.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a preferred embodiment of a catheter guide wire constructed according to the present invention and a manufacturing method thereof will be described in more detail with reference to the accompanying drawings.
[0010]
Referring to FIGS. 1 to 3, a catheter guide wire constructed in accordance with the present invention comprises a metal core 2 and a synthetic resin protective coating 4.
[0011]
It is important that the core 2 is composed of a center wire 6 and a covering material 8 covered with the center wire 6 . Centered wires 6 are caused to extend continuously from the proximal end 2a of the core 2 to the tip 2b. The cross-sectional shape of the center wire 6 may be circular. Center wire 6 that is formed of an alloy having N i-Ti alloy, Cu-Zn-Al-based alloy, Cu-Al-Mn-based alloy, a superelastic such as Fe-Mn alloy. Coating material 8 is caused to cover the center wire 6 is formed from a relatively large having a modulus away stainless steel or copper-based alloy. The cross-sectional shape of the covering 8 covered with the center wire 6 may be an annular shape.
[0012]
The core 2 includes an intermediate portion 14 existing between the proximal end portion 10 and the distal end portion 12 together with the proximal end portion 10 and the distal end portion 12. It is important that the coating material 8 does not exist at the distal end portion 12 of the core 2 and the distal end portion 12 is formed only from the center wire 6. In the illustrated embodiment, the center wire 6 is gradually tapered at the tip 12 of the core 2. The outer diameter D1 of the center wire 6 at the tip 2b may be about 0.05 to 0.25 mm. At the proximal end portion 10 and the intermediate portion 14, the center wire 6 has a substantially constant outer diameter D2, which may be about 0.5 to 0.8 mm. In the intermediate part 14 of the core 2, the covering material 8 is gradually tapered. The thickness of the covering material 8 is substantially zero at the forefront of the intermediate portion 14, and the thickness T1 of the covering material 8 may be about 0.05 to 0.4 mm at the rearmost end of the intermediate portion 14. At the base end portion 10 of the core 2, the thickness T <b> 2 of the covering material 8 is substantially uniform, and is substantially the same as the thickness T <b> 1 at the rearmost end of the intermediate portion 14.
[0013]
The length of the core 2 of the tip 12 is Ri 1 00 to 300mm approximately der, the length of the proximal portion 10 is 500mm or more, preferably a 700 to 800 mm,, and the length of the intermediate portion 14 is 50 to 700 mm, preferably 100 to 600 mm,. Referring to the elastic modulus of the core 2 composed of the center wire 6 and the covering material 8, the tip 12 has a load of 0.8 mm in a three-point bending test in which the distance between both support points is 14 mm. It is preferably 6 kgf or less, particularly 0.4 kgf or less . Because that central wire 6 is caused to gradually tapered in the previous end 12, the elastic modulus are allowed reduced gradually toward the front end 2a. It is preferable that the base end portion 10 has a load of 0.7 kgf or more, particularly 0.8 to 1.0 kgf when the deflection is 0.8 mm in a three-point bending test in which the distance between both support points is 14 mm. At the base end portion 10, the elastic modulus is substantially constant. In the intermediate portion 14, since the covering material 8 is gradually tapered, the elastic modulus is gradually reduced toward the distal end portion 12.
[0014]
The core 2 in the illustrated embodiment can be conveniently manufactured as follows, for example. A central wire 6 having an outer diameter D2 is prepared, and a tubular covering material 8 is fitted on the central wire 6. The inner diameter of the covering material 8 when fitted may be sufficiently larger than the outer diameter of the center wire 6. Next, the covering material 8 is stretched in the length direction to gradually reduce the outer diameter and the inner diameter, and the inner peripheral surface of the covering material 8 is brought into close contact with the outer peripheral surface of the center wire 6. Are bonded firmly enough. In the core 2 formed in this way, as shown by a two-dot chain line in FIG. 4, the outer diameter of the center wire 6 and the thickness of the covering material 8 are the entire length from the base end 2a to the tip 2b. It is substantially constant. Thereafter, grinding is applied to the distal end portion 12 and the intermediate portion 14 of the core 2 to cut a portion indicated by a two-dot chain line in FIG. If desired, the center wire 6 can be plated to cover the covering 8. In the illustrated embodiment, the elastic modulus of the core 2 at the distal end portion 12 is gradually reduced toward the distal end 2a by gradually tapering the center wire 6 at the distal end portion 12. Alternatively, in addition to this, the center wire 6 can be subjected to a required heat treatment at the distal end portion 12 to gradually reduce the elastic modulus of the core 2 at the distal end portion 12.
[0015]
The synthetic resin protective coating 4 added to the core 2 can be applied in any suitable manner known to those skilled in the art. Examples of the synthetic resin that can be suitably used include polyurethane and flexible olefin polymers. A contrast medium such as tungsten powder can be mixed in the protective coating 4. The outer diameter of the protective coating 4 applied to the core 2, and hence the outer diameter of the catheter guide wire, may be on the order of 0.25 to 2.5 mm, and it is important that it is substantially constant over the entire length. Further, as shown in FIG. 1, it is important that the proximal surface and the distal end surface of the core 2 is also covered cracks in the protective coating 4. The guide wire for catheter may be in a form extending linearly over its entire length. Alternatively, as is well known to those skilled in the art, the tip can be curved into a required shape as shown by a two-dot chain line in FIG. Such bending can be realized, for example, by applying a required heat treatment to the center wire 6 at the tip of the core 2.
[0016]
【The invention's effect】
The catheter guide wire of the present invention can be manufactured without a significant increase in manufacturing cost, but the elastic modulus of the distal end portion can be made sufficiently small and the elastic modulus of the proximal end portion can be reduced within a required range. In addition to the above-described characteristics, various characteristics as described above required for a guide wire for a catheter can be provided .
[Brief description of the drawings]
FIG. 1 is a longitudinal cross-sectional view of a catheter guidewire constructed in accordance with the present invention.
2 is an enlarged longitudinal sectional view showing a distal end portion and an intermediate portion of the catheter guide wire in FIG. 1;
3 is a cross-sectional view of the catheter guide wire of FIG. 1 taken along line III-III.
4 is a longitudinal sectional view for explaining a manufacturing mode of a core of the guide wire for catheter of FIG. 1. FIG.
[Explanation of symbols]
2: Core 4: Protective coating 6: Center wire 8: Covering material 10: Base end portion 12: Tip end portion 14: Intermediate portion

Claims (4)

It is composed of a core wire formed from a superelastic alloy, a core covered with the core wire and formed from a stainless steel or copper alloy, and a synthetic resin protective coating,
The core at the base end portion having a length of 500 mm or more has a constant outer diameter of 0.5 to 0.8 mm and a constant thickness of 0.05 to 0.4 mm. It consists of a covering material,
The core in the middle part having a length of 50 to 700 mm is composed of the center wire and the covering material having a constant outer diameter of 0.5 to 0.8 mm, and the thickness of the covering material Is gradually reduced from the rearmost end, which is the same thickness as the covering material at the base end, to the leading edge, which is zero,
The core at the tip portion having a length of 100 to 300 mm is composed only of the center wire, and the outer diameter of the center wire is the same as the center wire at the intermediate portion, and the outer diameter is 0 from the rear end. Gradual reduction to the cutting edge of .05 to 0.25mm,
The protective coating covers the entire surface including the proximal end surface and the distal end surface of the core;
The outer diameter of the guide wire is constant over the entire length,
A guidewire for a catheter characterized by the above. The catheter guide wire according to claim 1, wherein a contrast agent is mixed in the protective coating . The tip has a load of 0.6 kgf or less when the deflection is 0.8 mm in a three-point bending test with a spacing of both support points of 14 mm, and the base end has a three-point bending test with a spacing of both support points of 14 mm. The catheter guide wire according to claim 1 or 2 , wherein a load at a deflection of 0.8 mm is 0.7 kgf or more.   A central wire formed from an alloy having superelasticity is coated with a tube-shaped coating material formed from stainless steel or a copper-based alloy, and then the coating material is stretched in the length direction so that the coating material is centered. The guide wire for a catheter according to any one of claims 1 to 3, wherein the guide wire is firmly bonded to the wire, and thereafter, the required portions of the covering material and the central wire are ground, and then a synthetic resin protective coating is applied. Method.

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