JP3763895B2 - Medical guide wire and molding method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a medical guide wire used for introducing a catheter into the cardiovascular system and a method for forming the same.
[0002]
[Prior art]
For the purpose of angiography, a catheter with a very thin flexible tube is inserted into the blood vessel, or when a balloon catheter is inserted into the blood vessel for the treatment of the occluded site of the coronary artery, it is safe to insert the catheter. In order to ensure, a medical guide wire made of a flexible wire is used, and many of them are disclosed in Japanese Patent Publication Nos. 4-12145, 4-20453, and 7-7652. There are known examples. And they have a common shape of a flexible ultrafine wire body that can be inserted into a blood vessel. By passing the catheter through a guide wire that has been inserted and set in the blood vessel in advance, the guide wire functions as a guide wire. The distal end is inserted and set at a predetermined position in the blood vessel, and then only the guide wire is pulled out to perform a predetermined treatment such as angiography.
[0003]
That is, (see FIG. 5), the guide wire 1 is inserted and pushed into a blood vessel or a branched blood vessel having a complicated path from the tip, so that it is flexible and has a vertical load with respect to the traveling direction (buckling resistance). In particular, the distal end part that leads the insertion is indispensable for high flexibility and flexibility, and in addition, the direction of the distal end part is controlled while rotating the proximal end part that goes out of the body to branch blood vessels, etc. Therefore, advanced mechanical properties having both torsional rigidity and steering performance are required.
[0004]
Therefore, the examples of the above-mentioned known examples No. 4-20453 and No. 7-7652 are formed in the narrow diameter portion 4 by narrowing only the length of the end of the core wire 2 of the ultrafine wire, and the narrow diameter portion. 4 having a circular cross-sectional shape with a uniform diameter in which the entire length of the core wire 2 including 4 is embedded in the resin coating 3 and using a twisted wire as the core wire 2, only one of the strands constituting the twisted wire is forward It is characterized by a structure that protrudes and is embedded in the resin coating 3.
[0005]
[Problems to be solved by the invention]
In the conventional structure described above, the portion having the small diameter portion 4 constitutes the guide wire tip portion 5 (hereinafter referred to as the tip portion 5), and has high flexibility and high flexibility. Due to the circular cross-sectional shape of the diameter, the bending rigidity of the guide wire 1 becomes uniform in all directions, and there are the following problems.
[0006]
That is, in order to facilitate the insertion into the blood vessel, the pre-shaping process in which the distal end portion 5 is photographed with a fingertip and is plastically deformed to provide the “curve-shaped bent portion 8” immediately before the insertion is “unidirectional bending rigidity” In other words, it is difficult to bend due to the absence of a bending point, and it is difficult to obtain a bent portion 8 having a predetermined shape.
[0007]
When the distal end portion 5 reaches the blood vessel branch point and the steering operation is performed to guide the bent portion 8 to the direction of the branch blood vessel to be inserted, the distal end portion 5 facilitates the bending direction of the bent portion 8 due to the intravascular resistance. The guide wire 1 may be difficult to introduce into the branch blood vessel, making the insertion of the guide wire 1 into the blood vessel complicated and time consuming, increasing patient pain.
[0008]
Furthermore, since the core wire 2 is made of a stranded wire, since the locking force between the strands of the thin-diameter portion 4 is weak, the strands of the strand are unwound by bending of the bent portion 8 and released from the resin coating 3. There is a possibility that the resin coating 3 is peeled off or the strands are exposed. The present invention provides a guide wire that solves the above-mentioned problems of the prior art.
[0009]
[Means for Solving the Problems]
The guide wire of the present invention that solves the above technical problems is composed of a wire body in which a core wire having a small diameter portion at the tip of a long metal round wire is wrapped with a resin coating, and the thin diameter portion is In the medical guide wire which forms the inner part of the tip part wrapped with the resin coating as the guide wire tip part of the blood vessel insertion guide,
[0010]
“The main part of the guide wire other than the tip of the guide wire has a circular cross section with a uniform diameter, the core wire of the guide wire tip is a metal round wire, and the resin coating has a different shape with different vertical and horizontal lengths. It is characterized by a structure in which a bending point that is easy to bend only in a uniaxial direction is provided, and a bending point that is easy to bend is provided only in a uniaxial direction passing through the wire axis .
[0011]
That is, the guide wire according to the present invention has the front end portion having the above-mentioned deformed shape, so that only one axial direction can be easily bent, and a suitable bending rigidity can be ensured in directions other than the one axial direction to secure the distal end of the guide wire. It is characterized by a structure that imparts the necessary mechanical properties to the part. In the present invention, the circle means a perfect circle or an approximate circle, and the irregular cross-sectional shape other than the circle means a substantially rectangular flat shape, polygon, ellipse, oval, etc., which is a crushed circle. . As the core wire of the guide wire of the present invention, a single strand of wire, a twisted strand of strands, or a superelastic alloy wire / shape memory alloy wire, etc. are used as necessary, and the twisted wire is used. Adopts a mode in which a thin-diameter portion is formed in the form of a stranded wire, and a wire fixing portion in which the strands are fixed to each other at the tip of the thin-diameter portion.
[0012]
[Action]
In the guide wire of the present invention having the above-described configuration, the distal end portion leading to the insertion into the blood vessel can be easily bent and deformed only in the uniaxial direction, and appropriate bending rigidity can exist in directions other than the uniaxial direction. Therefore, it is easy to perform a pre-ape process for providing the “bow-shaped bent portion 8” for insertion into the blood vessel, and the shape and bending direction of the bent portion 8 are stabilized. And even if it receives insertion resistance due to a constricted state or a bent shape of the blood vessel in the blood vessel, the bending direction of the bent portion 8 is not easily disturbed, and the bending direction is stable. It becomes easy to do.
[0013]
Furthermore, those that fix the ends of twisted strands maintain the function as a twisted wire in the portion processed to have a small diameter, and lock the stranding of the strands. Defects that cause protrusion exposure can be prevented. And the said shaping | molding method can shape | mold the guide wire of this invention simply and efficiently only by setting the front-end | tip part of a guide wire element | base_body to the shaping die, and pressing.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, it demonstrates in detail with reference to FIG. 1 which shows 1st embodiment of this invention. That is, the guide wire 1 of the present invention has a circular cross-sectional shape with a uniform diameter D by enclosing a core wire 2 of an ultrafine stainless steel wire with a resin coating 3 (nylon 12 coating or the like) into a single wire body. 2 is a guide wire distal end portion 5 (hereinafter, simply referred to as a distal end portion 5) that guides blood vessel insertion. The shape of the guide wire main portion 6 other than the distal end portion 5 is crushed into a substantially rectangular irregular cross section having two parallel surfaces.
[0015]
Specifically, the distal end portion 5 of the irregular cross-sectional shape has a uniform substantially rectangular cross-sectional shape composed of a long side L equal to the diameter D of the guide wire main portion 6 and a short side S corresponding to the thickness. It has a flat-pointed round shape with the diameter portion 4 in the center. Further, the X axis of the center line in the long side L direction passing through the longitudinal axis 7 of the small diameter portion 4 is used as a bending point that is easy to bend, and there is a corresponding bending rigidity in directions other than the X axis. It has a structure to make it. The above-described guide wire 1 according to the embodiment of FIG. 1 has the above-described action, and the tip portion 5 can be easily pre-shaped, so that the shape quality of the “curve-shaped bent portion 8” is stabilized, and the blood vessel of the guide wire 1 The workability of the internal insertion is improved, and the leading of the distal end portion 5 to the branch blood vessel is facilitated.
[0016]
Then, the shaping | molding method of the guide wire 1 of FIG. 1 embodiment is demonstrated based on FIG. That is, a guide wire body 10 in which a resin wire 3 (nylon 12 or the like) is applied to a core wire 2 whose end portion is processed into a narrow diameter portion 4 is formed in advance by the same method as that of the known example. Subsequently, the end portion of the guide wire body 10 is composed of a pair of upper and lower mating molds 11A and 11B in which a shaping cavity 12 aligned with the shape of the tip portion 5 is recessed, and has heating means such as a heater. The resin coating 3 is softened by pressing with the matching molds 11A and 11B and crushed and shaped, the tip of the small diameter portion 4 is wrapped with the resin coating 3, and the substantially rectangular shape is provided. A guide wire 1 having a tip portion 5 having a predetermined shape, such as, is formed. According to the molding method of this embodiment, the guide wire 1 having the tip portion 5 having a predetermined shape can be molded with high efficiency by a simple construction method.
[0017]
Next, another embodiment of the present invention will be described with reference to FIG. That is, in this embodiment, a known twisted wire 13 in which about 3 to 5 strands 14 are twisted as the core wire 2 in the case of having the tip portion 5 having a deformed cross section having a bending point only in the uniaxial direction. Is used, and a portion of the end of the stranded wire 13 becomes a narrowed portion 4 reduced in a twisted form, and the strands 14 at the ends of the narrowed portion 4 are secured to each other. 15. In addition, the strand fixing part 15 of this embodiment is formed by the brazing process by a gold | metal material or a silver material.
[0018]
In the guide wire 1 according to the embodiment shown in FIG. 3, even if the distal end portion 5 is bent to a small radius of curvature or repeatedly bent in the blood vessel, the strands 14 are untwisted and may be released from the resin coating 3. There are few, and defects, such as peeling of the resin coating 3, are prevented, the performance and quality of the front-end | tip part 5 are stabilized, and the thing of the flexibility and flexibility which the thing of a twisted wire structure is superior to the single wire of the same diameter can be enjoyed. it can.
[0019]
In other words, when a stranded wire of the same diameter is compared with a single wire, the flexibility and rigidity of the single wire are generally limited depending on the material, but the stranded wire is more flexible and flexible than the single wire and can be made by a twisted configuration. The range of change in flexibility and rigidity can be set intentionally wide. Therefore, when the stranded wire is adopted as the guide wire core wire, the variable selection region of the mechanical property as the guide wire becomes large, and the “higher quality” can be obtained. And by improving the insertion property in the blood vessel by improving the flexibility of the guide wire, it is possible to reduce the application of a hydrophilic polymer or the like applied to the outer periphery in order to improve the insertion property of the guide wire into the blood vessel, and a stranded wire Since there are ridges formed by twisting on the outer periphery, the adhesion of the resin coating is improved, there is no risk of resin peeling due to insertion bending in the blood vessel, and the quality of the guide wire is improved and stabilized.
[0020]
The guide wire 1 of the present invention is not limited to the above-described embodiment, and the deformed cross-sectional shape of the tip portion 5 is a length in which a bending point having a neutral plane in one axis direction of the X axis as illustrated in FIG. 4 exists. It is made circular, elliptical, polygonal, etc., the planar shape of the tip portion 5 is made slightly wider than the guide wire main portion 6, or it is made a multistage shape whose thickness changes in the longitudinal direction, or the tip portion 5 There are changes such as a taper taper shape and a continuous taper portion and straight portion. The formation of the wire fixing part 15 may be performed by other fixing means than the above.
[0021]
【The invention's effect】
As described above, the guide wire of the present invention improves the pre-shape processability during insertion into the blood vessel and the insertion property into the blood vessel, so a series of operation processes for catheter insertion preparation work for angiography and the like As a result, the efficiency of the treatment is improved by improving the treatment efficiency, and the one made of a core wire having a twisted wire structure prevents the occurrence of defects such as peeling of the resin coating and enjoys the merit of the twisted wire. Further improvement can be promoted. The guide wire forming method can efficiently form the useful guide wire and provide it at a low cost. There are the above various effects.
[Brief description of the drawings]
FIG. 1 shows a distal end portion of a medical guide wire according to a first embodiment of the present invention, in which (A) is a front view thereof, (B) is a side view thereof, (C) is an EE sectional view of (B), FIG. 2D is an FF cross-sectional view of FIG. 2B. FIG. 2 is an explanatory view of a method for forming a medical guide wire in the embodiment of FIG. 1. FIG. 3 is a front view of a distal end portion of a medical guide wire in another embodiment of the present invention. FIG. 4 shows a distal end portion of a medical guide wire according to another embodiment of the present invention, wherein (A), (B), (C), and (D) are transverse sectional views, respectively, and (E) is a side view thereof ( F) is a front view thereof. FIG. 5 is a front view of a distal end portion of a conventional medical guide wire.
DESCRIPTION OF SYMBOLS 1 Medical guide wire 2 Core wire 3 Resin coating | cover 4 Thin diameter part 5 Tip part 6 Guide wire main part 7 Axis center 8 Bending part 10 Guide wire element | base_body 11A * 11B Molding die 12 Cavity 13 Stranded wire 14 Strand 15 Wire adhering part

Claims (4)

Consists of a wire body in which a core wire made of a small diameter part of the long metal round wire is wrapped in a resin coating, and the internal part of the tip part wrapped in the resin coating is inserted into a blood vessel. In the medical guide wire formed with the leading guide wire tip portion, the guide wire main portion other than the guide wire tip portion has a uniform-diameter circular cross section, and the core wire of the guide wire tip portion is a metal round wire and is coated with resin. Is a medical guide wire characterized in that it has an irregular shape with different vertical and horizontal lengths in the cross section and is provided with a bending point that facilitates bending only in one axial direction passing through the wire shaft axis . The medical guide wire according to claim 1, wherein the cross-sectional shape of the resin coating at the distal end portion of the guide wire is substantially rectangular or rhombus having two parallel surfaces . The medical guide wire according to claim 1, wherein the cross-sectional shape of the resin coating at the distal end portion of the guide wire is a multistage shape in which the thickness changes thinly toward the distal end side in the longitudinal direction . The core wire is composed of a strand of 3 to 5 strands, and a strand fixing portion in which the strands of the strands are fixed to each other at the tip of the small diameter portion. A medical guide wire according to crab.

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