JPH11178931A - Guide wire for catheter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a catheter with flexibility and restoration and excellent in repeated formability. SOLUTION: This guide wire for catheter is equipped with a core 5 and a cover body 6 to cover the core 5. The tip end part of the core 5 must be a composite wire part 5a formed by twisting plural steel wires 12 around a Ni-Ti alloy wire 11 with properties of super elasticity or work-hardening type. When a couple of forces is applied on the composite wire part 5a of the core 5, large stress is not produced in the steel wires 12 and a slip is generated between the Ni-Ti alloy wire 11 and the steel wires 12 forming the composite wire part 5a to deform. Even if the couple of forces is removed, a desired shape after deformation is kept by the friction force generated between the Ni-Ti alloy wire and the steel wires 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a guide wire for a catheter for guiding a catheter to a predetermined position in a blood vessel.

[0002]

2. Description of the Related Art A flexible and elongated cylindrical catheter is introduced into a blood vessel at a predetermined position for treatment or examination.
In the case of indwelling, after inserting the distal end side of the catheter guide wire into the blood vessel, the distal end opening of the catheter is inserted into the proximal end of the inserted catheter guide wire, and the catheter is gradually moved. Introduced into the blood vessel and left in place.

[0003] The catheter guide wire facilitates the introduction of the catheter by guiding the catheter as the axis of the catheter during the operation of introducing the catheter.

[0004] The guide wire for a catheter is required to have flexibility, resilience to deformation and the like so as to be able to be smoothly inserted into a blood vessel without damaging the blood vessel wall of the meandering blood vessel.

To meet this demand, conventionally,
The inner core of the catheter guide wire is formed of a wire such as stainless steel or tungsten.

Further, as described in Japanese Patent Publication No. 24548/1990, for example, a catheter in which the inner core of a guide wire for a catheter is formed of a Ni-Ti alloy wire having superelastic properties is known. I have.

Further, as described in Japanese Patent Publication No. 6-83726, Ni-Ti having a work hardening type characteristic in which the load increases smoothly as the elongation increases and a constant load portion does not clearly appear. 2. Description of the Related Art A guide wire for a catheter having an inner core formed of an alloy wire is known.

As shown in FIG. 7, a catheter guide wire including an inner core 1 formed of the above wire material and having a substantially circular cross section, and a synthetic resin covering 2 covering the inner core 1. The distal end portion 3 of FIG. 8 is generally inserted into a substantially J-shaped portion as shown in FIG.
It is bent in advance into a letter shape or a mild angle shape shown in FIG.

However, the shape of the blood vessel bifurcation varies from patient to patient, and in an actual clinical site, the clinician may use his / her fingertip or the like to form the tip 3 which has been processed into a straight shape or an angle shape in advance. In some cases, it is necessary to deform the blood vessel bifurcation into a shape corresponding to the shape of the blood vessel bifurcation of each patient to shape the blood vessel into a desired shape.

[0010]

However, a guide wire for a catheter in which the inner core 1 is formed of a Ni-Ti alloy wire having super-elastic or work-hardening characteristics as in the prior art described above, has a super-elastic characteristic and the like. In order to have, the tip 3 is deformed to a shape corresponding to the shape of the blood vessel bifurcation at a clinical site because it is flexible and sufficiently flexible, and has a relatively large elastic strain that can be restored. The shaping operation is substantially difficult.

Further, in the conventional guide wire for a catheter in which the inner core 1 is made of a wire material such as stainless steel or tungsten, the guide wire for a catheter can be formed into a desired shape. When deformed and shaped into a desired shape for use, there is a problem that the material is liable to be broken due to fatigue of the material due to repeated loading.

Further, when the distal end portion 3 of the catheter guide wire in which the inner core 1 is formed of a steel wire material is repeatedly plastically deformed and shaped into a desired shape and used, the distal end portion 3 is attached to a fingertip or the like. When the tip 3 is plastically deformed by applying a couple force to the tip 3 to generate a stress greater than the elastic limit, the material is locally hardened. Since the yield stress in the portion not reaching the plastic region is small, the longitudinal axis of the distal end portion 3 is in a meandering state due to preferential yielding and the like, and cannot be adapted to clinical use. There is.

In order to eliminate the necessity of shaping the blood vessel into a desired shape corresponding to the shape of the blood vessel bifurcation at the clinical site, the distal end is bent at various angles in advance, for catheters having various distal shapes. It is conceivable to prepare a guidewire and use it appropriately selected according to the patient, but in addition to the management of multiple guidewires for catheters, the task of selecting from multiple guidewires is also complicated. Is inconvenient.

The present invention has been made in view of the above points, and has the required flexibility and resilience, and can be formed into a desired shape. It is an object of the present invention to provide a guide wire for a catheter which is hardly damaged by fatigue and does not have a meandering longitudinal axis at the tip end even when it is shaped.

[0015]

According to a first aspect of the present invention, there is provided a guide wire for a catheter, comprising: an inner core; and a coating covering at least a distal end of the inner core. Or Ni-Ti having work hardening characteristics
It is a composite wire portion formed by twisting a plurality of steel wires around an alloy wire.

At the clinical site, when the distal end of the inner core is deformed into a shape corresponding to the shape of the blood vessel bifurcation or the like of the patient, when a bending moment due to couple is applied to the composite wire portion of the inner core, The inner composite wire portion is made of Ni
-Since a plurality of small-diameter steel wires are formed by twisting around the Ti alloy wire, the stress due to bending at the same curvature is small because the diameter is small, and the inside of the steel wire forming the inner core composite wire portion is reduced. Slip occurs between the Ni-Ti alloy wire forming the inner core composite wire and the steel wire without causing a relatively large stress, and the steel wire is deformed.

Next, even if the applied couple is removed, the desired shape after deformation is maintained by the frictional force generated between the Ni-Ti alloy wire and the steel wire.

According to a second aspect of the present invention, there is provided the catheter guide wire according to the first aspect, wherein a plurality of steel wires are twisted around a Ni-Ti alloy wire having superelastic or work hardening characteristics. The tip portion of the inner core is formed by the composite wire portion formed as described above.

Since the distal end portion of the inner core is formed of the composite wire portion, the distal end of the catheter guide wire is deformed into a shape corresponding to the shape of a blood vessel bifurcation or the like of a patient.

According to a third aspect of the present invention, in the catheter guide wire according to the first or second aspect, the Ni-Ti alloy wire is stored in a linear shape in advance.

Since the Ni-Ti alloy wire is stored in a linear shape in advance, it is difficult for the wire to buckle during the insertion operation into the meandering blood vessel, and the tip of the inner core during the rotation operation. The torque can be transmitted accurately.

[0022]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a catheter guide wire according to an embodiment of the present invention.

FIG. 1 is a partially cutaway plan view showing an embodiment of a guide wire for a catheter, and FIG.
FIG. 2 is a sectional view taken along the line AA of FIG.

The flexible catheter guide wire shown in FIGS. 1 and 2 includes an inner core 5,
And a cover 6 that covers the entire inner core 5.

The entire inner core 5, including the distal end portion to be inserted into the blood vessel in advance, is formed of the composite wire portion 5a.

The composite wire portion 5a of the inner core 5 covers the entire outer peripheral surface of the Ni-Ti alloy wire 11 around the Ni-Ti alloy wire 11 having superelastic or work hardening characteristics. A plurality of steel wires 12 are twisted to form a linear and elongated shape.

The length of the composite wire portion 5a of the inner core 5 is, for example, 1500 mm to 1800 mm, and the thickness of the composite wire portion 5a is, for example, 0.3 mm to 0.7 mm.

The Ni—Ti alloy wire 11 has superelastic or work-hardening characteristics.
A wire consisting of 57% by weight of Ni and the balance of Ti, or
Either one of Ni and Ti or a part of both Ni and Ti is replaced with another element such as Co, Cu, Al, F
e, a wire rod substituted with Zn, Cr, V, Mo, etc.,
A wire rod having a characteristic of drawing a stress-strain diagram (I, II) as shown in FIG. 3, for example, by processing a material melted by an ultraclean melting process to a predetermined size and subjecting it to a predetermined heat treatment or the like. It is.

The Ni—Ti alloy wire 11 having the characteristics of the stress-strain diagram (II) in FIG. 3 is a Ni—Ti alloy having superelastic characteristics that draws the stress-strain diagram (I) in FIG. Unlike the wire rod 11, this is a work hardening type Ni-Ti alloy wire rod that does not have the constant stress portion C of the diagram (I) and that the stress σ smoothly increases with an increase in the strain ε.

The Ni—Ti alloy wire 11 is stored in a linear shape, for example, in advance.

On the other hand, the steel wire 12 is a wire such as carbon steel, stainless steel or the like mainly containing Fe, and a schematic diagram of a stress-strain diagram of the steel wire 12 is as shown in FIG. In FIG. 4, the stress corresponding to the point E is the elastic limit σ _e , and the area up to the point E is the elastic range. When the stress exceeds the point E, the plastic enters the plastic range. Was.

Next, the covering 6 is made of a synthetic resin material such as polyurethane, polyamide, polyethylene, polyvinyl chloride, polyester, polypropylene, polystyrene, silicon or the like, and is coated on the outer peripheral surface of the composite wire portion 5a of the inner core 5. The coating 6 is entirely covered, and the distal end and the proximal end of the coating 6 are formed in a hemispherical shape, and are slightly thicker than other portions.

Next, the operation of the above embodiment will be described.

At the medical site, when inserting a guide wire for a catheter into a blood vessel, a clinician or the like grasps the shape of the blood vessel bifurcation of the patient in advance and, for example, uses the blood vessel bifurcation 21 as shown in FIG. In some cases, the clinician or the like shapes the linear tip of the guide wire for the catheter into a desired shape corresponding to the shape of the vascular bifurcation 21 of the patient with his / her fingertip.

The operating temperature of the guide wire for a catheter at the medical site is generally the same as that of the composite wire portion of the inner core 5.
It is higher than the shape recovery temperature of the Ni—Ti alloy wire 11 forming 5a.

In a shaping operation to a desired shape at the medical site, a clinician or the like uses a fingertip or the like to make a composite wire portion forming the distal end of the inner core 5 of the catheter guide wire.
When a bending moment due to an appropriate couple is applied to the tip portion of 5a, the composite wire portion 5a of the inner core 5
-Since a plurality of small-diameter steel wires 12 are formed by twisting around the Ti alloy wire 11, the stress due to bending at the same curvature is small due to the small diameter, and this steel wire is
The inner core 5 has no relatively large stress inside.
Slip occurs between the Ni—Ti alloy wire 11 and the steel wire 12 forming the composite wire portion 5a.

Due to the slip, the distal end portion of the linear composite wire portion 5a of the inner core 5 is bent and deformed into a desired shape.
For example, it bends and deforms in a mild angle shape.

Next, when the applied couple is removed, the inner core 5 is removed.
The end portion of the composite wire portion 5a attempts to restore the original linear shape by elasticity, but cannot withstand the frictional force generated between the Ni-Ti alloy wire 11 and the steel wire 12, The distal end portion of the composite wire portion 5a of the inner core 5 is maintained in a state of being bent and deformed into a desired shape such as a mild angle shape.

After the shaping operation into the desired shape,
A clinician or the like uses a Seldinger needle or the like to percutaneously insert the distal end of the catheter guide wire into the blood vessel 22, and directs the distal end of the catheter guide wire to a predetermined position in the blood vessel 22, Move slowly.

In this movement, when the distal end of the catheter guide wire reaches the vascular bifurcation 21 as shown in FIG. 5, if the distal end of the catheter guide wire is moved while rotating, Ni- Since the Ti alloy wire 11 is stored in a linear shape in advance and the torque is accurately transmitted to the distal end of the inner core 5, the distal end of the catheter guide wire does not buckle and the distal end of the blood vessel bifurcation 21. It passes through the blood vessel bifurcation 21 smoothly without damaging the blood vessel wall.

Since the distal end of the catheter guide wire has the required flexibility and resilience, it is inserted toward a predetermined position in the blood vessel without damaging the blood vessel wall of the meandering blood vessel.

After inserting the distal end of the catheter guide wire to a predetermined position in the blood vessel, the distal end opening of the catheter is inserted into the proximal end of the catheter guide wire located outside the patient's body. Is gradually introduced into the blood vessel.

Next, after introducing the distal end of the catheter to a predetermined position in the blood vessel around the catheter guide wire, the catheter guide wire located in the catheter is pulled out of the blood vessel to the outside of the body. ing.

Then, various medical instruments (not shown) are inserted from the catheter to treat the affected part, or a medicine or the like flows into the catheter and the medicine or the like is injected into the affected part via the catheter and inspected.

As described above, according to the above-described embodiment, a plurality of steel wires 12 are twisted around the Ni-Ti alloy wire 11 having superelastic or work-hardening characteristics at the tip of the inner core 5. The composite wire portion 5a formed together has the required flexibility and resilience, and is a stranded wire of a small-diameter wire, so that the steel wire 12 forming the composite wire portion 5a of the inner core 5 is formed.
The tip of the catheter guide wire can be shaped into a desired shape by a frictional force without generating a relatively large stress inside the steel wire rod 12 and a relatively large stress is not generated inside the steel wire rod 12. Even if it is formed into a desired shape, it is hard to be broken by fatigue and the longitudinal axis of the composite wire portion 5a does not meander.

Further, the distal end of the catheter guide wire can be easily deformed into a shape corresponding to the shape of the blood vessel bifurcation 21 of the patient, and can be easily returned to the original linear state.

Furthermore, since the entirety including the distal end of the inner core 5 is formed by the composite wire portion 5a, if the distal end and the proximal end have the same shape, the leading end or the base end is required for shaping work into a desired shape. It is not necessary to select the end, and the operability can be improved.

Further, since the Ni—Ti alloy wire 11 is stored in a linear shape in advance, it is possible to suppress the occurrence of buckling during the insertion operation and to reach the tip of the inner core 5 during the rotation operation. Torque can be transmitted accurately and the operability can be further improved.

Further, since the entire inner core 5 is formed as the composite wire portion 5a, the manufacturing process can be easily automated and the manufacturing cost can be reduced.

In the above-described embodiment, the inner core 5 is entirely formed of the composite wire portion 5a. However, for example, as shown in FIG. Alternatively, a composite wire portion 5a formed by twisting a plurality of steel wires 12 around a Ni-Ti alloy wire 11 having work-hardening characteristics, and Ni-Ti other than the tip portion.
A structure formed by a single wire portion 5b such as an alloy wire 11 or a steel wire 12 can also be used.

The length of the composite wire 5a of the inner core 5 shown in FIG. 6 is, for example, 300 mm to 800 mm, and the length of the single wire 5b of the inner core 5 is, for example, 700 mm to 1 mm.
200 mm. The thickness of the composite wire portion 5a and the single wire portion 5b of the inner core 5 is, for example, 0.3 mm to 0.7 mm.
mm.

According to the catheter guide wire shown in FIG. 6, even if it is repeatedly formed into a desired shape, it is hardly damaged by fatigue and the longitudinal axis of the composite wire portion 5a does not meander. Not only that, the use of the Ni—Ti alloy wire 11 only at the tip where shaping is required can prevent an increase in material cost.

In the above-described embodiment, the structure in which the covering 6 covers the entire inner core 5 has been described. However, the covering 6 may be configured to cover only the distal end of the inner core 5.

Further, the structure in which the composite wire portion 5a of the inner core 5 is formed in a linear shape and an elongated shape has been described. However, it is not always necessary that the composite wire portion 5a be a linear shape. It may be configured to have a character shape or a mild angle shape. The Ni-Ti alloy wire 11 forming the central axis of the composite wire portion 5a of the inner core 5 has been described as being stored in a linear shape in advance. However, it is not necessary that the Ni-Ti alloy wire 11 be linear. Approximately J with curved tip
It may be configured to have a character shape or a mild angle shape.

[0055]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A catheter guide wire of the present invention, for example, a catheter guide wire having the structure shown in FIG. 1, is different from a conventional catheter guide wire even if it is repeatedly formed into a desired shape for a long time. It was confirmed by experiments that it was applicable to practical use, that is, it had excellent repetitive moldability.

Table 1 shows the results of the experiment.

[0057]

[Table 1] In Table 1, ○ indicates the case where the tip shape change was practically about 10 times, and × indicates the case where the tip shape change was not practically about 10 times.

Table 2 shows the materials and dimensions of the No. 1 to No. 4 conventional products and the No. 5 to No. 12 invention products in Table 1.

[0059]

[Table 2] The materials A to D in Table 2 are as follows.

Material A is a Ni-Ti alloy consisting of 56.03% by weight of Ni and the remaining Ti.

Material B is 11.7% by weight of Ni, 17.
SUS316 consisting of 2% by weight of Cr, 2.4% by weight of Mo and the balance of Fe.

The material C is a high-strength steel wire composed of 0.2% by weight of C, 0.8% by weight of Si, 1.0% by weight of Mn, and the balance of Fe.

Material D is 12.1% by weight of Ni,
SUS316 consisting of 9% by weight of Cr, 2.5% by weight of Mo and the balance of Fe.

[0064]

According to the first aspect of the present invention, at least the front end of the inner core is formed by twisting a plurality of steel wires around a Ni-Ti alloy wire having superelastic or work hardening characteristics. The flexibility required for the composite wire section,
Since it has resilience and is a stranded wire of a small diameter wire, it can be formed into a desired shape by frictional force without causing relatively large stress inside the steel wire forming the composite wire part of the inner core. Moreover, since a relatively large stress is not generated inside the steel wire, even if the steel wire is repeatedly formed into a desired shape, the steel wire is hardly damaged by fatigue and the longitudinal axis of the composite wire does not meander.

According to the second aspect of the present invention, since the distal end of the inner core is formed by the composite wire portion, the distal end of the catheter guide wire can be easily formed into a shape corresponding to the shape of the blood vessel bifurcation of the patient. It can be deformed and can be easily returned to the original linear state.

In addition, the portion other than the tip portion, which does not require shaping the inner core into a desired shape, is, for example, a single wire portion, thereby preventing an increase in material cost.

According to the third aspect of the present invention, Ni-Ti
Since the alloy wire is stored in a linear shape in advance, the occurrence of buckling during the insertion operation can be suppressed, the torque can be accurately transmitted to the tip of the inner core during the rotation operation, and the operability can be improved. .

[Brief description of the drawings]

FIG. 1 is a partially cutaway plan view showing an embodiment of a catheter guide wire of the present invention.

FIG. 2A shows a guide wire for a catheter according to the first embodiment;
It is -A sectional drawing.

FIG. 3 is a stress-strain diagram of a Ni—Ti alloy wire forming an inner core of the catheter guide wire.

FIG. 4 is a stress-strain diagram of a steel wire forming an inner core of the catheter guide wire.

FIG. 5 is a perspective view showing a blood vessel bifurcation into which the catheter guide wire is inserted.

FIG. 6 is a partially cutaway plan view showing another embodiment of the catheter guide wire of the present invention.

FIG. 7 is a cross-sectional view taken along line BB of FIGS. 8 and 9 showing a conventional guide wire for a catheter.

FIG. 8 is a partially cutaway plan view showing a conventional catheter guide wire.

FIG. 9 is a partially cutaway plan view showing another conventional catheter guide wire.

[Explanation of symbols]

 5 Inner core 5a Composite wire 6 Coating 11 Ni-Ti alloy wire 12 Steel wire

Claims (3)

[Claims] 1. An inner core, and a coating covering at least a distal end of the inner core, wherein at least a distal end of the inner core surrounds a Ni-Ti alloy wire having superelastic or work-hardening characteristics. A guide wire for a catheter, comprising a composite wire portion formed by twisting a plurality of steel wires to each other. 2. N having superelastic or work-hardening properties
The guide wire for a catheter according to claim 1, wherein a distal end portion of the inner core is formed by a composite wire portion formed by twisting a plurality of steel wires around the i-Ti alloy wire. 3. The Ni—Ti alloy wire is stored in a linear shape in advance.
The guide wire for a catheter according to the above.