JP5622201B2 - Guide wire and catheter - Google Patents

Description

The present invention relates to a gas guide wire and catheter.

  Conventionally, a metal material having improved physical properties such as surface hardness and wear resistance by performing a surface treatment such as a carburizing treatment or a nitriding treatment is known.

  For example, Patent Document 1 discloses a metal material in which a hardened surface layer is formed by nitriding the surface of a stainless steel substrate having a predetermined composition. Such metal materials are said to be excellent in strength and wear resistance.

JP 2005-53694 A

  However, when a tube body manufactured using the conventional metal material described in Patent Document 1 is bent beyond a certain curvature, there is a problem that cracks are likely to occur in the surface hardened layer.

  When the present inventor has studied to solve the above problems, the surface hardened layer made of iron nitride has a higher hardness than the stainless steel base, and therefore the surface hardened layer has cracks when the tube body is bent. It was found to occur. And as a result of continuing examination based on the knowledge concerned, the present inventor completed the cylindrical body of the present invention.

The inner surface of the cylindrical body of the present invention is formed from iron nitride having a relatively high hardness. Therefore, the cylindrical body of the present invention is less likely to be kinked even when bent more than a certain curvature, compared to a cylindrical body formed entirely from a metal having a lower hardness than iron nitride.
In addition, when a cylindrical body is bent, generally a larger compressive force or tensile force (hereinafter also simply referred to as an external force) is applied to the outer surface than to the inner surface, so that cracks occur on the outer surface. Cheap.
However, since the outer surface of the cylindrical body of the present invention is formed from a metal having a lower hardness than iron nitride, even if a large external force is applied to the outer surface by bending the cylindrical body, Cracks are unlikely to occur on the surface, and breakage due to the progress of cracks is unlikely to occur.
In addition, in this specification, hardness shall mean Vickers hardness (HV).

The guide wire according to the present invention includes a cylindrical body having an inner surface formed of iron nitride and an outer surface formed of a metal having a hardness lower than that of the iron nitride. .

The catheter of the present invention is characterized by including a cylindrical body having an inner surface formed from iron nitride and an outer surface formed from a metal having a hardness lower than that of the iron nitride. To do.

Fig.1 (a) is a perspective view which shows typically an example of the cylindrical body of this invention, FIG.1 (b) is the sectional view on the AA line of the cylindrical body shown to Fig.1 (a). FIG.1 (c) is a side view of the cylindrical body shown to Fig.1 (a). It is a whole view showing typically an example of the guide wire of the present invention. 1 is an overall view schematically showing an example of a catheter of the present invention.

(First embodiment)
Hereinafter, a first embodiment which is an embodiment of the present invention will be described with reference to the drawings.

(Cylindrical body of this embodiment)
Fig.1 (a) is a perspective view which shows typically an example of the cylindrical body of this invention, FIG.1 (b) is the sectional view on the AA line of the cylindrical body shown to Fig.1 (a). FIG.1 (c) is a side view of the cylindrical body shown to Fig.1 (a).

  The cylindrical body 1 of this embodiment shown in FIG. 1A is made of metal.

  The inner surface 2 of the cylindrical body 1 is made of iron nitride. Therefore, the cylindrical body 1 of the present embodiment is less likely to be kinked even when bent by a certain curvature or more, compared to a cylindrical body that is entirely formed of a metal having a lower hardness than iron nitride.

Further, the outer surface 3 of the cylindrical body 1 is formed of a metal having a hardness lower than that of iron nitride.
In this embodiment, the outer surface 3 is formed from stainless steel.
Therefore, even when a large external force is applied to the outer surface 3 by bending the cylindrical body 1, cracks are unlikely to occur on the outer surface 3 made of stainless steel, and breakage due to the progress of cracks is unlikely to occur.
Moreover, since the balance of the hardness of the inner surface made of iron nitride and the hardness of the outer surface made of stainless steel is balanced, the kink resistance and crack resistance are higher, and the corrosion resistance is higher.

  Examples of the stainless steel include stainless steels such as martensitic stainless steel, ferritic stainless steel, austenitic stainless steel, austenite, ferrite duplex stainless steel, and precipitation hardened stainless steel. Among these, austenitic stainless steel is desirable, and SUS304, SUS316 or SUS316L is more desirable.

The outer diameter of the cylindrical body 1 is preferably 0.2 to 0.7 mm. It is because it is excellent in kink resistance and crack resistance as the outer diameter of a cylindrical body is 0.2-0.7 mm.
On the other hand, if the outer diameter of the cylindrical body is less than 0.2 mm, the outer diameter of the cylindrical body may be too small and the kink resistance may be lowered.
On the other hand, if the outer diameter of the cylindrical body exceeds 0.7 mm, the outer diameter of the cylindrical body may be too large and the crack resistance may be lowered.

The inner diameter of the cylindrical body 1 is desirably 0.1 to 0.6 mm. When the inner diameter of the cylindrical body is 0.1 to 0.6 mm, the size of the central cavity is not too small, and gas, liquid, etc. and medical machine instruments can easily pass through the central cavity. For example, in a catheter configured to include the cylindrical body 1 of the present invention, a medical machine instrument such as a guide wire can easily pass through the central cavity without resistance.
Further, when the inner diameter of the cylindrical body is 0.1 to 0.6 mm, the size of the central cavity is not too large, and the kink resistance and crack resistance are excellent.
On the other hand, if the inner diameter of the cylindrical body is less than 0.1 mm, the inner diameter of the cylindrical body is too small, and it becomes difficult for gas, liquid, etc. and medical equipment to pass through the central cavity.
Moreover, when the internal diameter of a cylindrical body exceeds 0.6 mm, the internal diameter of a cylindrical body may be too large, and kink resistance and crack resistance may become low.

A surface coating layer made of resin or the like may be further formed on at least one of the outer surface and the inner surface of the cylindrical body 1. When the surface coating layer is formed on the outer surface, the strength of the cylindrical body can be improved, and by selecting the type of resin as necessary, the cylindrical body is formed in a large diameter tubular body. This is because the resistance when inserting the body can be changed.
In addition, when the surface coating layer is formed on the inner surface, by appropriately selecting the type of resin as necessary, gas, liquid, etc. and medical machinery / equipment circulate in the central cavity of the cylindrical body. This is because the resistance during the process can be reduced.

  Examples of the material for the surface coating layer include HDPE (high density polyethylene), LLDPE (linear low density polyethylene), polyvinyl chloride, polyethylene, polypropylene, ethylene-propylene copolymer, and ethylene-vinyl acetate copolymer. Such as polyolefin, polyethylene terephthalate, polyester such as polybutylene terephthalate, polyurethane, polyamide, polyimide, polytetrafluoroethylene, polyvinylidene fluoride, other thermoplastic resins such as fluororesin, thermosetting resin, polyamide elastomer, polyester elastomer Thermoplastic elastomers, various rubbers, cellulosic polymer materials, polyethylene oxide polymer materials, maleic anhydride polymer materials (for example, methyl vinyl ether-maleic anhydride copolymer) A maleic anhydride copolymer such as a polymer), an acrylamide polymer (for example, a block copolymer of polyacrylamide, polyglycidyl methacrylate-dimethylacrylamide), water-soluble nylon, polyvinyl alcohol, polyvinyl pyrrolidone, hyaluronate, etc. Resin material is mentioned.

  The cylindrical body of this embodiment can be manufactured by the following method.

When manufacturing the cylindrical body in which the outer surface is formed from stainless steel, the cylindrical body of this embodiment can be manufactured by performing a nitriding process to the cylindrical base material formed from stainless steel, for example.
Examples of the nitriding treatment include nitriding treatments such as a gas nitriding method, a salt bath nitriding method, a gas soft nitriding method, and an ion nitriding method.
In addition, you may manufacture the cylindrical body of a desired outer diameter and internal diameter by performing a nitriding process to the cylindrical base material of a large diameter, and performing a caging process and a drawing process after that.

(Guide wire of this embodiment)
Next, the guide wire of this embodiment will be described in detail below with reference to the drawings.

  FIG. 2 is an overall view schematically showing an example of the guide wire of the present invention.

The guide wire 4 shown in FIG. 2 includes a core shaft 5 and a coil body 6 that covers the tip 5b of the core shaft 5. In the most advanced portion 7, the core shaft 5 and the coil body 6 are fixed.
In addition, the full length of the guide wire 4 is 500-2000 mm, and an outer diameter is 0.1-0.5 mm.

  The core shaft 5 is formed by tapering the cylindrical body 1 of the present embodiment described above, and has a tapered shape with a diameter reduced from the base end portion 5a side toward the tip end portion 5b side.

A tip member 11 made of a material such as a superelastic alloy such as a Ni—Ti alloy, a piano wire, or a tungsten wire is attached to the tip portion 5 b of the core shaft 5.
The tip member may not be attached.

  The coil body 6 is made of a strand wound in a spiral shape around the tip portion 5 b of the core shaft 5. The strands constituting the coil body 6 are martensitic stainless steel, ferritic stainless steel, austenitic stainless steel, austenite, ferrite duplex stainless steel and precipitation hardened stainless steel, super-elastic alloy such as Ni-Ti alloy, tungsten wire, It is made of a material such as platinum, gold or tungsten which is a radiopaque metal. The strand diameter is preferably 0.03 to 0.08 mm.

Among the coil bodies 6, the coil tip brazing part 8, the coil intermediate brazing part 9 located on the base end part 5 a side of the coil tip brazing part 8, and the base end part of the coil intermediate brazing part 9 The coil base end brazing portions 10 located on the 5a side are brazed to the distal end portion 5b of the core shaft 5 and are fixed to the core shaft 5.
In addition, the coil intermediate brazing part 9 does not need to be one place, and a plurality of coil intermediate brazing parts may be formed.

  Examples of the brazing material described above include aluminum alloy brazing, silver brazing, gold brazing, zinc, Sn—Pb alloy, Pb—Ag alloy, and Sn—Ag alloy.

  As shown in FIG. 2, the coil body 6 is wound between the coil tip brazing portion 8 and the coil intermediate brazing portion 9 so that a gap is generated between adjacent strands. It is desirable to wind between the brazing part 9 and the coil base end brazing part 10 so that adjacent strands come into contact with each other.

Although the strand diameter of the strand of the coil body 6 shown in FIG. 2 is the same diameter, the strand diameter of the coil body 6 is gradually narrowed from the base end portion 5a side of the coil body 6 toward the distal end portion 5b. It may be.
When the wire diameter of the coil body 6 is gradually reduced from the base end portion 5a in the direction of the distal end portion 5b, the flexibility of the distal end portion 5b can be gradually increased. Can be curved.
In this case, the strand diameter of the strand closer to the tip portion 5b than the coil intermediate brazing portion 9 may be formed smaller than the strand diameter of the other strands. The flexibility on the tip 5b side of the coil intermediate brazing portion 9 can be increased, and this is effective when performing a curve having a relatively small radius of curvature in the region on the tip 5b side of the coil intermediate brazing portion 9. Because.

  It is desirable that the outer surfaces of the core shaft 5 and the coil body 6 are coated with a hydrophilic material. This is because the sliding resistance of the guide wire 4 in the catheter, tubular organ or body tissue can be reduced and the guide wire 4 can be moved smoothly.

  Examples of the hydrophilic material include cellulose-based polymer materials, polyethylene oxide-based polymer materials, and maleic anhydride-based polymer materials (for example, maleic anhydride copolymers such as methyl vinyl ether-maleic anhydride copolymer). Acrylamide polymer materials (for example, polyacrylamide, polyglycidyl methacrylate-dimethylacrylamide block copolymer), water-soluble nylon, polyvinyl alcohol, polyvinyl pyrrolidone, hyaluronate and the like. Of these, hyaluronate is more desirable.

  The guide wire of this embodiment uses the cylindrical body of this embodiment having high kink resistance and crack resistance as a constituent member of the core shaft. For this reason, the guide wire of the present embodiment is difficult to kink, has excellent torque transmission properties, and hardly breaks even when it is bent more than a certain curvature in procedures such as percutaneous coronary angioplasty.

The guide wire of the present embodiment is prepared by, for example, producing a core shaft by subjecting the cylindrical body of the present embodiment to taper processing, and inserting the coil body into the tip of the produced core shaft, and then the core shaft and the coil body Can be manufactured by brazing.
Examples of the taper processing include cutting processing such as centering polishing, caging processing, and drawing processing.

  Next, the catheter of this embodiment will be described with reference to the drawings.

  FIG. 3 is an overall view schematically showing an example of the catheter of the present invention.

The catheter 12 of this embodiment includes a catheter shaft 13 and a connector 14. In FIG. 3, the lower end in the figure is the tip 12a side (distal side) inserted into the body, and the upper end in the figure is the rear end 12b side operated by an operator such as a doctor. (Near side, proximal side).
In addition, the full length of the catheter 12 is 800-1500 mm, an outer diameter is 1.0-3.0 mm, and an internal diameter is 0.8-2.5 mm.

  The catheter shaft 13 includes a shaft main body portion 13a, a shaft distal portion 13b positioned closer to the tip portion 12a than the shaft main body portion 13a, and a tip 15 attached to the tip of the shaft distal portion 13b. .

  The shaft main body 13a is formed by processing the cylindrical body 1 of the present embodiment described above into a predetermined shape. In the present embodiment, the diameter of the catheter 12 is reduced from the rear end portion 12b side toward the distal end portion 12a side.

  The shaft distal portion 13b is made of a material having higher flexibility than the shaft main body portion 13a. Therefore, when the catheter 12 is inserted into the body, the distal end portion 12a of the catheter 12 can be deformed according to the shape of the coronary artery hole or the like. The shaft distal portion 13b may be, for example, a tubular body including a resin inner cylinder, a metal braid surrounding the outer peripheral surface of the inner cylinder, and a resin outer cylinder surrounding the outer peripheral surface of the braid. Good.

Examples of the material for the resin inner cylinder include PTFE (polytetrafluoroethylene) fluorine-based resin and HDPE (high density polyethylene) resin.
Examples of the braiding material include stainless steel (SUS304) and tungsten.
Examples of the material of the resin outer cylinder include polyolefins such as polyethylene, polypropylene, and polybutadiene, soft, hard polyvinyl chloride, polyurethane, epoxy resin, cycloolefin, ethylene-vinyl acetate copolymer, polyethylene terephthalate, polybutylene terephthalate, and the like. Polyester, Nylon 12, Nylon 11, Nylon 610, Nylon 612, Nylon 66, Nylon 6 and other polyamides, polyether polyamide, polyether block amide, polyester polyamide, ABS resin, AS resin, fluorine resin, shape memory resin, etc. Various resin materials, styrene, polyolefin, polyurethane, polyester, polyamide, polybutadiene, trans polyisoprene, fluoro rubber, chlorinated polyethylene Various thermoplastic elastomer resin etc., silicone, thermoset elastomer resins such as vulcanized rubber, furthermore, a combination of two or more of these (polymer alloys, polymer blends, laminates, etc.).

The tip 15 is a cylindrical member that constitutes the distal end opening of the catheter 12 and is made of a material such as a highly flexible resin.
As said resin, resin, such as a polyurethane elastomer, is mentioned, for example.

When manufacturing the catheter of this embodiment, the shaft body is manufactured by tapering the cylindrical body of this embodiment, and the distal end portion of the shaft including a tip is attached to the tip of the manufactured shaft body. This produces a catheter shaft.
Next, a connector is attached to the rear end of the shaft main body portion of the produced catheter shaft. The catheter of this embodiment can be manufactured through the above steps.
Examples of the taper processing include cutting processing such as centering polishing, caging processing, and drawing processing.

  The catheter of this embodiment uses the tubular body of this embodiment having high kink resistance and crack resistance as the shaft body. Therefore, the catheter of the present embodiment is difficult to kink and hardly break even when it is bent beyond a certain curvature in a procedure such as percutaneous coronary angioplasty.

(Other embodiments)
In the cylindrical body of the present invention, the outer surface of the cylindrical body is made of a metal whose hardness is lower than that of iron nitride, but the metal whose hardness is lower than that of iron nitride is not limited to the above-described stainless steel, for example, copper, Non-ferrous metals such as aluminum and Ni-Ti may be used. When manufacturing the cylindrical body in which the outer surface was formed from the nonferrous metal, you may carry out by fixing an iron nitride particle | grain to the inner surface of the cylindrical base material formed from the nonferrous metal, for example.

  Although the cylindrical body of the present invention can be suitably used for the above-described guide wire and catheter, it can also be suitably used as a constituent member of a catheter for intravascular ultrasound (IVUS).

DESCRIPTION OF SYMBOLS 1 Cylindrical body 2 Inner surface of a cylindrical body 3 Outer surface of a cylindrical body

Claims (2)

A guide wire comprising a cylindrical body having an inner surface made of iron nitride and an outer surface made of a metal having a lower hardness than the iron nitride . A catheter comprising a cylindrical body having an inner surface formed from iron nitride and an outer surface formed from a metal having a lower hardness than the iron nitride .

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