JP2004154286A - Guide wire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a guide wire having flexibility at its distal end to prevent the damage to the inner wall of a tubular organ and having sufficient push-ability. <P>SOLUTION: The guide wire comprises covering the surface of a core wire 20 with a resin. The distal end of the core wire 20 has a taper part 22 contracted in its diameter in a tapered form and a flattened part 23 continuously extending from the taper part 22 to be flattened. The flat part 23 is bent into a J-shape toward the flat surface direction thereof and keeps the bent distal end preferably bent so as to be deviated in a lateral direction with respect to the proximal end of the flat part 23. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a guidewire used to guide the distal end of a catheter to a target site when inserting the catheter into a tubular organ of a human body such as a blood vessel, a ureter, a bile duct, and a trachea.
[0002]
[Prior art]
In recent years, for examination and treatment of tubular organs of the human body such as blood vessels, ureters, bile ducts, and trachea, a catheter is inserted to administer a drug such as a contrast agent, or a part of the tissue is collected with forceps or the like through the catheter. Or that is being done. In addition, by inserting and arranging a stent through a catheter, for example, a treatment for arranging and expanding a stent in a stenotic part of a blood vessel, or arranging a stent in a place where an aneurysm is formed to prevent rupture of the aneurysm Methods are known.
[0003]
Then, when inserting the catheter, first, a relatively thin and flexible guide wire is inserted into the tubular organ, and the distal end of the guide wire reaches a target location, and then the catheter is moved along the outer periphery of the guide wire. Insert and pull out the guide wire.
[0004]
As the guide wire, a core wire made of a Ti—Ni alloy, stainless steel, or the like, whose outer periphery is covered with a resin, or the like is used. The core wire for the guide wire is thin enough to be easily inserted into the target tubular organ, flexible at the distal end so as not to damage the inner wall of the tubular organ, and sufficiently pressed into the tubular organ. It is desired that the guide wire also has the rigidity of the main body, and in particular, in recent years, a guide wire that satisfies the above-mentioned performance is required even in a thin and meandering tubular organ.
[0005]
As such a guide wire, it is known to bend the distal end portion of the guide wire into a J-shape. This can prevent the distal end of the guidewire from damaging the inner wall of the tubular organ, and can easily guide the distal end of the guidewire in a target direction.
[0006]
As a guide wire having such a tip bent in a J-shape, for example, Japanese Patent Publication No. Sho 62-20827 discloses that at least the tip of the guide wire has a martensitic reverse transformation start temperature of 0 ° C to 40 ° C. A guide wire is disclosed, which is made of a shape memory alloy and is formed to have a J shape at a temperature higher than the temperature.
[0007]
[Patent Document 1]
Japanese Patent Publication No. Sho 62-20827
[Problems to be solved by the invention]
However, in a guide wire disclosed in the above-mentioned Japanese Patent Publication No. Sho 62-20827, the core wire of the J-shaped portion at the tip remains cylindrical. Therefore, there is a problem that the flexibility in the J-shaped bent portion of the tip becomes insufficient, and the tubular organ may be damaged at the time of insertion and withdrawal, particularly when applied to a thin and meandering tubular organ. Was.
[0009]
At this time, it is conceivable to improve the flexibility of the distal end simply by thinning the core wire of the distal end, but in this case, the rigidity of the base at the time of insertion into the tubular organ is insufficient, so-called push There is a problem that the pushability is poor and insertion becomes difficult. Further, when the core wire is made thinner, there is also a problem that the J-shaped portion undulates and deforms due to shrinkage stress of the coating resin.
[0010]
Therefore, an object of the present invention is to provide a flexible distal end portion to prevent damage to the inner wall of the tubular organ during insertion and withdrawal, while providing sufficient pushability so that the guidewire can be easily inserted. To provide a guidewire provided with the guidewire.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, a first aspect of the present invention is a guide wire in which the surface of a core wire is coated with a resin, and a tip portion of the core wire has a tapered portion whose diameter is reduced in a tapered shape, and the guide wire is continuous with the taper. And a flattened flat portion that extends in the direction of the flat surface, and wherein the flat portion is bent in a J-shape toward the direction of the flat surface.
[0012]
According to the first aspect, the flattened portion is provided at the tip bent in the J-shape to make the tip thinner, so that the flexibility of the tip is increased and damage to the tubular organ at the time of insertion or withdrawal is prevented. Can be. In addition, since the flat portion is provided only in the J-shaped portion, it is possible to provide a guide wire that does not reduce the pushability at the time of insertion and that allows easy selection of the course at the bifurcation of the tubular organ.
[0013]
According to a second aspect of the present invention, in the first aspect, the flat portion is bent in a J-shape, and the bent tip is bent so as to be shifted in a width direction with respect to a base end of the flat portion. To provide a suitable guidewire.
[0014]
According to the second aspect, the distal end portion of the J-shape is shifted in the width direction with respect to the base end portion of the flat portion, so that the distal end portion of the J-shape can intersect the base end portion of the flat portion. . This makes it possible to make the J-shaped bent portion small. Also, since the J-shaped tip can be prevented from coming into contact with the base end of the flat portion, it is possible to prevent the J-shaped tip from being joined to the base end of the flat portion with the resin when coating the resin. Thus, the yield at the time of resin coating can be improved. Furthermore, since the tip becomes easy to grasp, it becomes easy to perform an insertion operation into the catheter.
[0015]
A third aspect of the present invention is to provide a guide wire according to the first or second aspect, wherein a diameter of an inner circumference of the portion covered with the resin and bent in a J-shape is 3 mm or less. .
[0016]
According to the third aspect, since the portion bent in a J-shape is sufficiently small, it is easy to insert even when inserted into a thin tubular organ, and damage to the inner wall of the tubular organ can be prevented. A guidewire can be provided.
[0017]
A fourth aspect of the present invention provides the guide wire according to any one of the first to third aspects, wherein the flat portion is formed by pressing and crushing a cylindrical portion.
[0018]
According to the fourth aspect, the flat portion is obtained by pressing and crushing the columnar portion, whereby a transition is formed in the processed portion and plastic deformation is facilitated. Therefore, by increasing the processing rate of the core wire, a J-shape can be formed without heat treatment.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
1 to 3 show one embodiment of a guide wire according to the present invention. FIG. 1 is a side sectional view of the distal end portion of the guide wire, FIG. 2 is an explanatory view showing a method of processing the distal end portion of the core wire of the guide wire, FIG. 3 is an external perspective view of the core wire of the guide wire, and FIG. It is a schematic diagram of a medical device introduction device using the same guide wire.
[0020]
As shown in FIG. 1, the guide wire 10 mainly includes a core wire 20 and a resin film 30 covering the outer periphery of the core wire 20. The core wire 20 has a tapered portion 22 that continuously extends from the main body portion 21 and has a tapered diameter, and a flattened flat portion 23 that continuously extends from the tapered portion 22.
[0021]
The material of the core wire 20 is not particularly limited, and stainless steel, an alloy having a basic composition of Ni and Ti, or the like can be used. Ni-Ti alloy, Ni-Ti-X (X is Fe, Cu, V, Co, etc.) ) It is preferred to use an alloy. As the above-mentioned metal, a metal processed into a wire having a predetermined wire diameter by a known method such as hot forging, hot rolling, or cold working can be used.
[0022]
The tapered portion 22 is processed into a tapered shape by means of etching, machining, or the like in order to impart flexibility and appropriate pushability. However, the shape may be stepwise and gradually reduced in diameter.
[0023]
The flat portion 23 is bent in a J-shape toward the direction of the flat surface as shown in FIG. The flat portion 23 can be formed, for example, by the following method as shown in FIG.
[0024]
That is, first, as shown in FIG. 2A, a cylindrical portion 24 extending continuously from the tapered portion 22 is formed. This cylindrical portion 24 is processed by means such as etching, machining, or the like, similarly to the tapered portion 22 described above.
[0025]
Next, the cylindrical portion 24 is pressed and crushed by, for example, a pair of dies, and forged into a flat portion 23 ′ having a flat shape as shown in FIG. 2B. Then, as shown in FIG. 2C, the flat portion 23 'is bent toward the direction of the flat surface to form the J-shaped flat portion 23.
[0026]
As described above, in the present invention, it is preferable to form the flat portion 23 by pressing and crushing the columnar portion 24, whereby a transition is formed in the flat portion 23, so that plastic deformation is facilitated and heat treatment is performed. The J-shaped shaping can be easily performed without performing.
[0027]
In this case, it is preferable that the initial wire diameter t ₁ of the cylindrical portion 24 and the thickness t ₂ of the flat portion 23 ′ after forging be t ₂ / t ₁ = 0.9 to 0.3. . In addition, as the cold working, in addition to the forging as described above, a method such as pulling and twisting may be adopted.
[0028]
The degree of bending of the flat portion 23 is appropriately selected depending on the application location and the patient. However, as shown in FIG. 1, the diameter A of the inner circumference in the J-shaped portion where the resin film 30 is covered is shown. , Preferably 6 mm or less, more preferably 3 mm or less, and most preferably 2 mm or less. If the diameter of the inner circumference exceeds 3 mm, insertion into a particularly thin tubular organ becomes difficult, and the inner wall of the tubular organ is easily damaged, which is not preferable. Further, the entire length of the flat portion 23 is preferably 5 to 20 mm.
[0029]
As shown in FIG. 3, in this embodiment, the flat portion 23 is bent in a J-shape, and the bent distal end 23 a is shifted in the width direction with respect to the base end 23 b of the flat portion 23. It is bent.
[0030]
As a result, the flat portion 23 can be bent so that the distal end 23a intersects the base end 23b. Therefore, the curvature of the bent portion can be increased, and the J-shaped portion can be further reduced. Since it becomes possible to insert the tubular organ into the tubular organ while keeping it bent, it is possible to effectively prevent damage to the inner wall of the tubular organ.
[0031]
Also, when coating the resin 30, the tip 23a can be prevented from coming into contact with the base 23b, so that the tip 23a and the base 23b can be prevented from being joined by resin, and the Yield can be improved. Further, since the distal end 23a can be easily grasped by hand, the insertion operation into the catheter can be easily performed.
[0032]
In this case, it is preferable that the deviation width between the distal end 23a and the proximal end 23b is 0.5 to 3 mm. If the deviation width is less than 0.5 mm, the distal end 23a and the proximal end 23b come into contact with each other when the flat portion 23 is largely bent, which is not preferable. On the other hand, if it exceeds 3 mm, the inner wall may be damaged in the thin tubular organ, which is not preferable.
[0033]
In the present invention, heat treatment may be performed after the shaping. When the material of the core wire 11 is the above-described Ti-Ni alloy or the like, a heat treatment can be further performed to perform a memory treatment or a strain aging treatment. The memory treatment is performed by heat treatment at 400 ° C. or more, preferably 400 to 600 ° C., and the strain aging treatment can be performed by heat treatment at less than 350 ° C., preferably 200 to 340 ° C. When the memory treatment is performed, so-called superelasticity can be imparted and the flexibility is excellent, but the rigidity on the base side is insufficient and the pushability tends to be inferior. In contrast, when subjected to strain aging treatment, it becomes a material without a transformation point, the flexibility is slightly inferior to superelasticity, but it is better than stainless steel, and the base side rigidity is higher than superelasticity Push ability can be improved.
[0034]
The entire length of the core wire 20 is preferably 500 to 3000 mm. The diameter of the main body 21 of the core wire 20 is appropriately set in the range of 0.2 to 1.0 mm according to the purpose. Further, the length of the tapered portion 22 in the core wire 20 is preferably 50 to 200 mm.
[0035]
The outer periphery of the core wire 20 is covered with a resin film 30. As the resin film 30, for example, polyurethane, polyether block amide, polyethylene, polyvinyl chloride, polyester, polypropylene, polyamide, polystyrene, fluorine resin, silicon resin, and the like are preferably used. Further, the resin film 30 may contain a radiopaque material. As the X-ray opaque material, for example, powder such as bismuth, barium sulfate, or tungsten is preferably used. As a method of coating the resin film 30, a method of extruding the resin film 30 around the core wire 20 using an extrusion molding apparatus or the like is adopted, and is not particularly limited.
[0036]
Further, the outer periphery of the resin film 30 is preferably covered with a hydrophilic resin film (not shown). The hydrophilic resin film is a resin having a hydrophilic group such as —OH, —CONH ₂ , —COOH, —NH ₂ , —COO ⁻ , and —SO ₃ ^—, and is preferably bonded to the surface of the resin film 30. Those having a functional group that can be used are preferably employed. For example, as the resin film 30, a resin having an isocyanate group remaining or a resin having a reactivity with an isocyanate group is used. When a resin having a reactivity with an isocyanate group is used, a compound having an isocyanate group is further reacted. After that, a method of bonding a hydrophilic resin such as polyvinylpyrrolidone and polyethylene glycol via these isocyanate groups is preferably used. The method of forming such a hydrophilic resin film is described in detail in, for example, JP-A-5-184666, JP-A-7-80078, and JP-A-7-124263.
[0037]
The guide wire 10 is inserted into a tubular organ by, for example, an introduction device 40 as shown in FIG. That is, the introduction device 40 includes the guide wire 10, a cylindrical catheter 41 inserted into the tubular organ together with the guide wire 10, and a stopper 42 provided at a proximal end of the catheter 41. The wire 10 is attached so as to penetrate the inside of the cylinder of the catheter 41 and the plug 42.
[0038]
Then, in this state, the guide wire 10 can be inserted into the tubular organ by performing an insertion operation while sealing the guide wire 10 with the plug 42.
[0039]
According to the guide wire 10, the distal end can be inserted into the tubular organ while being bent in a J-shape. The flexibility of the part is increased and as a result damage to the tubular organ during insertion and withdrawal can be prevented. Further, since the flat portion is only the J-shaped portion, even if the thickness of the flat portion 23 is reduced, the pushability of the entire distal end portion of the guide wire at the time of insertion is not reduced, and the tubular organ is not affected. The selection of the course at the branching section can be easily performed.
[0040]
【Example】
Example 1
After forming the core wire by the processing method as shown in FIG. 2, it was coated with resin to produce a guide wire as shown in FIG.
[0041]
As the material of the core wire 20, a Ti-Ni alloy was used, and a wire having a wire diameter of the main body 21 of 0.5 mm was formed by an ordinary method. Next, subjected to etching into a shape as shown in FIG. 2 (a), so that 150mm length of the tapered portion 22, the length of the cylindrical portion 24 becomes 20 mm, wire diameter _{t 1} is a 0.15mm core 20 were formed.
[0042]
The cylindrical portion 24 of the core wire 20 is pressed and crushed from above and below to form a flat portion 23 ′ having a thickness t ₂ of 0.1 mm as shown in FIG. As shown in FIG. 2C, a core wire 20 was obtained as a flat portion 23 by forming a J-shape.
[0043]
The surface of the core wire 20 is coated with urethane resin so that the entire wire diameter becomes 0.8 mm, and the surface is subjected to hydrophilic treatment with polyvinylpyrrolidone to obtain a guide wire of Example 1 as shown in FIG. Was.
[0044]
Note that the J-shaped bend was bent in a direction perpendicular to the bent surface such that the bent distal end 23a in FIG. 3 matched the base end 23b of the flat portion 23. The degree of bending was such that A, which is the inner diameter of the J-shaped portion covered with the resin in FIG. 1, was 3 mm.
[0045]
Example 2
A guide wire of Example 2 was obtained under the same conditions as in Example 1 except that the degree of the J-shaped bending in Example 1 was bent so that the inner diameter A was 4 mm.
[0046]
Comparative Example 1
Under the same conditions as in Example 1 except that the J-shaped bending in Example 1 was performed with the cylindrical portion 24 having a wire diameter of 0.15 mm as shown in FIG. A wire was obtained.
[0047]
Comparative Example 2
The guide of Comparative Example 2 under the same conditions as in Example 2 except that the J-shaped bending in Example 2 was performed with the cylindrical portion 24 having a wire diameter of 0.15 mm as shown in FIG. A wire was obtained.
[0048]
Test example 1
For the guide wires of Examples 1 and 2 and Comparative Examples 1 and 2, the tip flexibility was measured by the method shown in FIG.
[0049]
That is, as shown in FIG. 4, a J-shaped guide wire 50 is passed through a catheter 60 having an inner diameter of 1.3 mm and a length of 50 mm, and thereafter, the resistance load when pulled out at a speed of 50 mm / min in the direction of the arrow. The maximum value was measured. The results are summarized in FIG.
[0050]
As shown in FIG. 6, when Example 1 is compared with Comparative Example 1 and Example 2 is compared with Comparative Example 2, the load is lower in Examples 1 and 2, and the flat portion 23 is provided. It can be seen that the flexibility of the tip is improved as compared with Comparative Examples 1 and 2 in which the shape remains a cylinder.
[0051]
Test example 2
For the guide wires of Examples 1 and 2 and Comparative Examples 1 and 2, the distal end rigidity was measured by the method shown in FIG.
[0052]
That is, a 10 mm J-shaped portion of the guide wire is pressed against a resin plate 70 having a thickness of 1 mm, and the resistance load when pushing 1 mm at a speed of 10 mm / min along the arrow direction in FIG. The maximum value was measured. The results are shown in FIG.
[0053]
As shown in FIG. 8, when Example 1 and Comparative Example 1 are compared, and Example 2 and Comparative Example 2 are each compared, the values are almost the same. Therefore, in Examples 1 and 2 in which the flat portion 23 is provided, the flexibility of the distal end portion is improved as described above as compared with the comparative example in which the J-shaped portion remains a cylinder, while the guide is provided. The values of the rigidity at the base side of the wire are almost the same, which indicates that the pushability can be maintained.
[0054]
【The invention's effect】
As described above, according to the guidewire of the present invention, the distal end portion has flexibility and prevents damage to the inner wall of the tubular organ, while having sufficient pushability that does not easily deform during insertion of the guidewire. Can be provided. This guide wire is particularly preferably used for insertion into a thin and meandering tubular organ.
[Brief description of the drawings]
FIG. 1 is a side sectional view showing one embodiment of a guide wire according to the present invention.
FIG. 2 is an explanatory view showing a method of processing a distal end portion of a core wire of the guide wire.
FIG. 3 is an external perspective view of a core wire of the guide wire.
FIG. 4 is a schematic view of a medical device introduction device using the guide wire.
FIG. 5 is an explanatory diagram showing a method for measuring the flexibility of a tip portion in an example.
FIG. 6 is a table showing the results of measuring the flexibility of a tip portion in Examples.
FIG. 7 is an explanatory diagram showing a method of measuring the rigidity of the tip portion in the example.
FIG. 8 is a chart showing measurement results of tip rigidity in the examples.
[Explanation of symbols]
10 medical guide wire 20 core wire 21 the body portion 22 tapered portion 23, 23 'flat portion 23a tip 23b proximal portion 24 cylindrical portion 30 resin film 40 introducer 41 catheter 42 the plug _{t 1} wire diameter _{t 2} thickness A diameter

Claims (4)

A guide wire obtained by coating the surface of a core wire with a resin, wherein the distal end portion of the core wire has a tapered portion that reduces in diameter in a tapered shape, and a flattened flat portion that extends continuously to the taper. A guide wire, wherein the flat portion is bent in a J-shape toward the direction of the flat surface. The guide wire according to claim 1, wherein the flat portion is bent in a J-shape, and the bent tip is bent so as to be shifted in a width direction with respect to a base end of the flat portion. The guide wire according to claim 1 or 2, wherein the diameter of the inner periphery of the portion covered with the resin and bent in a J-shape is 3 mm or less. The guide wire according to claim 1, wherein the flat portion is formed by pressing and crushing a cylindrical portion.

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