JP4354523B1 - Medical guidewire - Google Patents

Abstract

The present invention provides a medical guide wire in which a coil spring is firmly fixed to a core wire, and the shaping length can be shortened as compared with a conventional one.
A core wire having a distal end side small diameter portion and a proximal end side large diameter portion having a larger outer diameter than the distal end side small diameter portion, and a distal end side small diameter portion of the core wire. A medical guide wire that is attached to the outer periphery along the axial direction and has a coil spring 20 that is fixed to the core wire 10 at least at the front end and the rear end, and a large diameter portion on the proximal end side of the core wire 10 14 and the coil outer diameter of the coil spring 20 are both 0.012 inches or less, and the tip of the coil spring 20 is fixed to the core wire 10 with Au—Sn solder, and Au—Sn solder. The length of the tip rigid portion is 0.1 to 0.5 mm.
[Selection] Figure 1

Description

  The present invention relates to a medical guide wire having a coil spring mounted on the outer periphery of a small-diameter portion on the distal end side of a core wire. More specifically, the coil spring has a high adhering strength to the core wire, and the shaping length in the shaping operation of the tip portion The present invention relates to a medical guide wire that can be made shorter than a conventional one and has excellent operability in a microchannel of a CTO lesion.

A guide wire for guiding a medical device such as a catheter to a predetermined position in a body cavity such as a blood vessel is required to have flexibility at the distal end.
For this reason, the outer diameter of the distal end portion of the core wire is made smaller than the outer diameter of the proximal end portion, and a coil spring is attached to the outer periphery of the distal end portion (distal end side small diameter portion) of the core wire. A guide wire intended to improve the flexibility of the distal end is known (see, for example, Patent Document 1).

  In order to attach the coil spring to the outer periphery of the small-diameter portion on the distal end side of the core wire, each of the front end portion and the rear end portion of the coil spring is usually fixed to the core wire with solder.

  Here, as the solder for fixing the front end portion and the rear end portion of the coil spring to the core wire, Ag-Sn solder is used because of its low melting point and easy handling.

The solder that has penetrated into the coil contacts the outer peripheral surface of the core wire at the front end portion and the rear end portion of the coil spring, so that the coil spring is fixed to the core wire.
Further, the tip of the coil spring is formed by solder that has not penetrated into the coil.

  Therefore, in order to secure the fixing force of the coil spring to the core wire, it is necessary to sufficiently infiltrate the solder inside the coil at the tip of the coil spring to be fixed to the distal end of the core wire having the smallest outer diameter. It is. Specifically, it is necessary to allow the solder (Ag—Sn solder) to penetrate into the coil within a range corresponding to about 6 to about 8 pitches of the coil spring.

A rigid portion (including a tip formed of solder) formed by solder filled in the coil is formed at the tip of the guide wire thus manufactured.
The length of the tip rigid portion (the length corresponding to about 6 to about 8 pitches of the tip and coil) is about 0.8 to 1.1 mm.

Recently, it has been desired to reduce the size of medical devices in order to achieve minimal invasiveness to patients.
Along with this, there is a demand for a thinner guide wire, and the present inventors develop a guide wire having a smaller wire diameter (0.010 inch) than the conventional one (wire diameter is 0.014 inch). It came to.

The 0.010 inch guide wire can greatly contribute to miniaturization of medical devices such as catheters.
Further, according to this guide wire, for example, operability when accessing a microchannel in a CTO (chronic total occlusion) lesion is also good.

JP 2003-299739 A

  A further improvement in operability is required for a guide wire inserted through a microchannel in a CTO lesion. For example, it is desired to reduce frictional resistance during operation in a microchannel. However, the reduction in frictional resistance is limited only by reducing the wire diameter of the guide wire.

By the way, when the guide wire is inserted into the microchannel, the operator performs bending (shaping) of the distal end portion thereof.
For example, as shown in FIG. 5, when a rotational torque is applied on the proximal end side of the guide wire by bending a portion having a length of 1.0 mm from the tip of the guide wire G by 45 °, The distal end rotates on a circle having a diameter of about 1.4 mm.

This shaping operation greatly affects the operability of the guide wire in the microchannel.
From the viewpoint of reducing frictional resistance in the microchannel, it is preferable to reduce the rotation diameter (operation area) at the distal end of the guide wire. For this purpose, the shaping length (the bending length of the tip) is preferable. ) Should be as short as possible, specifically 0.7 mm or less.

However, in the conventional guide wire, since there is the above-mentioned rigid portion of the tip, the shaping length cannot be set to 1.0 mm or less, and this cannot sufficiently reduce the frictional resistance.
Note that if the length of the rigid portion of the tip is shortened by narrowing the range in which the solder (Ag—Sn solder) penetrates, the fixing force of the coil spring to the core wire cannot be secured, and the core wire and the coil spring cannot be secured. If a tensile force is applied between them, the core wire inserted into the coil spring is pulled out.

The present invention has been made based on the above situation.
A first object of the present invention is to provide a medical guide wire in which the strength of fixing a coil spring to a core wire is high and the shaping length can be shortened as compared with the conventional one.
A second object of the present invention is to provide a medical guide wire excellent in operability in a microchannel of a CTO lesion.

The medical guide wire of the present invention is a core wire having a distal end side small diameter portion and a proximal end side large diameter portion having a larger outer diameter than the distal end side small diameter portion,
A medical guide wire having a coil spring attached to the outer periphery of the small-diameter portion on the distal end side of the core wire along the axial direction, and having a coil spring fixed to the core wire at least at the front end portion and the rear end portion;
The outer diameter of the large diameter portion on the proximal end side of the core wire and the coil outer diameter of the coil spring are both 0.012 inches or less,
The tip of the coil spring is fixed to the core wire with Au-Sn solder,
The length of the rigid portion of the tip end made of Au—Sn solder is 0.1 to 0.5 mm.

Here, the “tip rigid portion” means the tip portion of a coil spring (guide wire) that can no longer be bent freely by the solder that has penetrated into the coil. When the tip is formed by solder, The tip is also a part of the tip rigid portion.
Further, the “length of the tip rigid portion” refers to the length of the guide wire in the axial direction from the tip of the guide wire to the rear end of the solder that has penetrated into the coil.

In the medical guide wire of the present invention, the following forms are preferable.
(1) The outer diameter of the large diameter portion on the proximal end side of the core wire and the coil outer diameter of the coil spring are both 0.010 inches or less, particularly 0.006 to 0.010 inches.

(2) The coil pitch at the tip of the coil spring is 1.0 to 1.8 times the coil wire diameter, and Au—Sn solder is in a range corresponding to 1 to 3 pitch of the coil spring (long) In the coil).

(3) Resin is filled in the coil spring (a space surrounded by the outer periphery of the small-diameter portion on the distal end side of the core wire and the inner periphery of the coil spring), and the resin is provided on the outer periphery of the coil spring. A resin layer is formed, a hydrophilic resin layer is laminated on the surface of the resin layer, and a water-repellent resin layer is formed on the surface of the core wire.

(4) The coil spring includes a front end side densely wound portion having a coil pitch of 1.0 to 1.8 times the coil wire diameter, and a rear end side loosely wound coil having a coil pitch exceeding 1.8 times the coil wire diameter. It consists of parts.

(5) An intermediate portion including the front end side densely wound portion and the rear end side loosely wound portion of the coil spring is fixed to the core wire with Au—Sn solder.

(6) The core wire is made of stainless steel.

According to the medical guide wire according to claims 1 to 3, since the Au-Sn solder is used as the solder for fixing the tip of the coil spring to the core wire, the length of the tip rigid portion is 0. Despite being as short as 1 to 0.5 mm (the solder fixing area is narrow), the fixing strength of the coil spring to the core wire should be sufficiently high (higher than the breaking strength of the small diameter portion on the distal end side of the core wire). Even if a tensile force is applied to the core wire that is inserted into the coil spring, the core wire is not pulled out.
And since the length of the tip rigid portion is as short as 0.1 to 0.5 mm, the shaping length (bending length of the tip) can be shortened (0.7 mm or less). As a result, the microchannel The frictional resistance can be sufficiently reduced during the operation.
In addition, treatment in a narrow region that cannot be performed using a conventional guide wire is also possible.
The medical guide wire of the present invention has a thin wire diameter of 0.012 inches or less, a high fixing strength by Au—Sn solder, and a short tip rigid portion of 0.1 to 0.5 mm in the microchannel of the CTO lesion. Excellent operability.

According to the medical guide wire of the fourth aspect, the core wire and the coil spring can be integrated by filling the inside of the coil spring with the resin, and the torque transmission property and operability of the guide wire can be improved. It can be improved significantly.
Further, since the hydrophilic resin layer is laminated on the outer periphery of the coil spring through the resin layer made of the same resin as that filled in the coil spring, the hydrophilic resin layer is securely fixed and hydrophilic. The lubricity due to the functional resin can be stably expressed.

  In addition, since the water-repellent resin layer is formed on the surface of the core wire, it is possible to prevent the patient's blood from coming into contact with the metal constituting the core wire and causing allergies. Thus, adhesion of blood and the like can be reliably prevented. Moreover, the lubricity with respect to another medical device can be expressed.

  According to the medical guide wire of the fifth aspect, good contrast (visibility) can be expressed at the distal end portion (the distal end side closely wound portion) of the coil spring.

  According to the medical guide wire of the sixth aspect, the boundary region between the front end side closely wound portion and the rear end side loosely wound portion, where stress concentration is likely to occur, is fixed by the Au—Sn solder having a high fixing force. Therefore, the fixing strength of the coil spring to the core wire can be further improved.

It is the side view which fractured | ruptured one part which shows one Embodiment of the guide wire of this invention. It is the side view (figure for demonstrating a dimension) which fractured | ruptured a part which shows one Embodiment of the guide wire of this invention. FIG. 2 is a partially enlarged view of FIG. 1, (A) is a detailed view of part A, (B) is a detailed view of part B, and (C) is a detailed view of part C. It is a side view which shows the state which shaped the front-end | tip part of the guide wire. It is explanatory drawing which shows typically the state which shaped the front-end | tip part of the guide wire.

The guide wire shown in FIG. 1 has a core wire 10 and a coil spring 20.
The core wire 10 includes a distal end side small diameter portion 11 that is tapered so as to expand in the proximal direction, a tapered portion 13 that expands in the proximal direction, and a proximal end large diameter portion 14.
The distal end side small diameter portion 11, the taper portion 13, and the proximal end side large diameter portion 14 are integrally configured by the same wire (for example, a round bar member).

The cross section of the taper part 13 and the proximal end side large diameter part 14 is substantially circular.
The cross section on the proximal end side of the distal end side small diameter portion 11 is substantially circular, but the distal end side of the distal end side small diameter portion 11 may be formed into a plate shape by compressing the wire. In that case, the cross section is substantially rectangular.

  The material of the core wire 10 is not particularly limited, and examples thereof include metals such as stainless steel (for example, SUS316, SUS304), gold, platinum, aluminum, tungsten, tantalum, and alloys thereof. Then, it is made of stainless steel.

A water repellent resin layer is formed on the outer peripheral surface of the core wire 10.
As the resin constituting the water-repellent resin layer, any resin that is used for medical purposes and has water repellency can be used, and suitable resins include fluorine-based resins such as PTFE.

As shown in FIG. 2, the total length (L ₁ ) of the guide wire 1 is, for example, 1500 to 3000 mm, and is 1780 mm if a suitable example is shown.
In addition, the outer diameter (D ₁ ) of the proximal end side large-diameter portion 14 is usually 0.012 inches (0.305 mm) or less, preferably 0.010 inches (0.254 mm) or less, more preferably 0. 0.006 to 0.010 inch, and 0.010 inch is a preferable example.

Since the outer diameter (D ₁ ) of the proximal-end-side large-diameter portion 14 is 0.012 inches or less, the medical instrument such as a catheter used with the guide wire of the present invention can be reduced in size and further reduced in invasiveness. Can contribute.

The maximum outer diameter of the distal end side small-diameter portion 11, is not particularly limited smaller than the inner diameter of the coil spring 20, the outer diameter of the proximal end side large-diameter portion 14 (D ₁₎ 1/5 About 3/5.

The coil spring 20 constituting the guide wire 10 is attached to the outer periphery of the distal end side small diameter portion 11 of the core wire 10 along the axial direction.
The coil spring 20 is composed of a single wire, the coil pitch is 1.0 to 1.8 times the coil wire diameter, and the coil end 20 is 1.8 times the coil wire diameter. The X-ray opaque region is constituted by the leading end side densely wound portion 21 and a leading end tip to be described later.

The coil pitch in the front end side densely wound portion 21 is 1.0 to 1.8 times the coil wire diameter, and is 1.0 times if a suitable example is shown.
The coil pitch in the rear end side loosely wound portion 22 is 1.8 to 2.5 times the coil wire diameter, and is 2.0 times if a suitable example is shown.
As described above, by changing the coil pitch between the front end side and the rear end side, good contrast (visibility) can be expressed in the front end side closely wound portion 21.
When the same pitch is used over the entire coil spring, the X-ray opaque region becomes longer, resulting in a decrease in visibility.

In FIG. 2, the length (L ₂ ) of the coil spring 20 is, for example, 30 to 800 mm, and 115 mm if a suitable example is shown.
The length (L ₂₁ ) of the front end side densely wound portion 21 is 10 to 50 mm, for example, and is 30 mm if a suitable example is shown.
The length (L ₂₂ ) of the rear end side loosely wound portion 22 is, for example, 20 to 750 mm, and is 85 mm if a suitable example is shown.
The length (L ₃ + L ₂ ) from the front end of the guide wire 1 to the rear end of the coil spring 20 is 30 to 800 mm, for example, and is 115.2 mm if a suitable example is shown.
The length (L ₃ + L ₂₁ ) from the front end of the guide wire 1 to the rear end of the front end side tightly wound portion 21 is, for example, 10 to 50 mm, and is 30.2 mm if a suitable example is shown.

The coil outer diameter (D ₂ ) of the coil spring 20 is usually 0.012 inch (0.305 mm) or less, preferably 0.010 inch (0.254 mm) or less, more preferably 0.006 to 0.010. Inches are 0.010 inches.

When the outer diameter (D ₁ ) of the proximal end side large diameter portion 14 of the core wire 10 is 0.012 inch or less and the coil outer diameter (D ₂ ) of the coil spring 20 is also 0.012 inch or less, The operability when accessing the microchannel (for example, lubricity in the microchannel) is excellent.
Although the outer diameter of the wire which comprises the coil spring 20 is not specifically limited, Preferably it is 30-90 micrometers, and if it shows a suitable example, it is 60 micrometers.

  The material of the coil spring 20 is a material (X-ray opaque material) having good contrast with respect to X-rays, such as platinum, platinum alloy (for example, Pt / W = 92/8), gold, gold-copper alloy, tungsten, and tantalum. ).

  In the guide wire of the present embodiment, each of the front end portion, the rear end portion, and the intermediate portion (the boundary portion between the front end side densely wound portion 21 and the rear end side loosely wound portion 22) of the coil spring 20 is made of solder. The distal end side small-diameter portion 11 is fixed to the outer periphery.

As shown in FIGS. 1 and 3A, the tip of the coil spring 20 is fixed to the core wire 10 with Au—Sn solder 31.
That is, the Au—Sn solder 31 penetrates into the coil spring 20, and the Au—Sn solder 31 comes into contact with the outer periphery of the core wire 10 (distal end side small diameter portion 11). The portion is fixed to the core wire 10 (the distal end side small diameter portion 11).

As shown in FIG. 3A, the Au—Sn solder 31 penetrates into the coil in a range corresponding to 2 pitches of the coil spring 20.
In addition, a substantially hemispherical tip is formed by Au—Sn solder 31 that has not penetrated into the coil spring 20 at the tip of the coil spring 20.

As a result, the distal end portion of the guide wire of the present embodiment has a hardened tip portion of the Au-Sn solder 31 (the coil spring 20 that can no longer be freely bent by the Au-Sn 31 solder that has penetrated into the coil. A rigid portion formed by a tip portion and a tip chip formed by the Au—Sn solder 31 is formed.
The length of the rigid portion of the tip (the length from the tip of the guide wire 1 to the rear end of the Au—Sn solder 31 penetrating into the coil) (L ₄ ) is about 0.3 to 0.4 mm.

In the guide wire of the present invention, the length of the distal rigid portion is 0.1 to 0.5 mm. When the length of the tip rigid portion is less than 0.1 mm, it is not possible to sufficiently secure the fixing force of the coil spring to the core wire.
On the other hand, when the length of the tip rigid portion exceeds 0.5 mm, the shaping length (the outer length (L ₅₂ ) described later) cannot be 0.7 mm or less.

  In the guide wire of the present invention, the coil pitch at the tip of the coil spring is 1.0 to 1.8 times the coil wire diameter in order to make the length of the tip rigid portion 0.1 to 0.5 mm. In addition, it is preferable that the Au—Sn solder penetrates into the coil in a range corresponding to 1 to 3 pitches of the coil spring.

The medical guide wire of the present invention is characterized in that Au—Sn solder is used as solder for fixing the tip of the coil spring to the core wire.
The Au—Sn solder used in the present invention is made of, for example, an alloy of 75 to 80% by mass of Au and 25 to 20% by mass of Sn.

By fixing the stainless steel and platinum (alloy) using Au-Sn solder, the adhesive strength (tensile strength) is about 2.5 times that of the case of fixing with Ag-Sn solder. It is done.
For this reason, even when the length of the tip rigid portion is as short as 0.1 to 0.5 mm (when the penetration range of the solder is 1 to 3 times the coil pitch), the coil spring 20 is fixed to the core wire 10. The strength can be made sufficiently high. Specifically, the strength can be made higher than the tensile breaking strength of the small diameter portion 11 on the distal end side of the core wire 10. For this reason, even if a tensile force is applied between the coil spring 20 and the core wire 10, it is possible to prevent the core wire 10 from being pulled out.
In addition, Au—Sn solder is superior in contrast to Ag—Sn solder.
Furthermore, Au—Sn solder is superior in corrosion resistance to blood and body fluids than Ag—Sn solder.

As shown in FIG. 1 and FIG. 3B, an intermediate portion including a boundary region between the front end side densely wound portion 21 and the rear end side loosely wound portion 22 of the coil spring 20 is made of Au-Sn solder 32 and core wire. 10 is fixed.
That is, the Au—Sn solder 32 is permeated into the coil spring 20, and the Au—Sn solder 32 comes into contact with the outer periphery of the core wire 10 (distal end side small diameter portion 11). The intermediate part is fixed to the core wire 10 (distal end side small diameter part 11).
Stress concentration easily occurs in the boundary region between the front end side densely wound portion 21 and the rear end side sparsely wound portion 22, and the intermediate portion including this boundary region is fixed by Au—Sn solder having a high fixing force, thereby obtaining a coil. The fixing strength of the spring 20 can be further improved.

As shown in FIGS. 1 and 3C, the rear end portion of the coil spring 20 is fixed to the core wire 10 with Ag—Sn solder 33.
That is, the Ag—Sn solder 33 penetrates into the coil spring 20, and the Ag—Sn solder 33 comes into contact with the outer periphery of the core wire 10 (distal end side small diameter portion 11). The rear end portion is fixed to the core wire 10 (distal end side small diameter portion 11).
In the distal end side small diameter portion 11 of the core wire 10, the outer diameter of the portion to which the rear end portion of the coil spring 20 is fixed is larger than the outer diameter of the portion (distal end) to which the tip portion of the coil spring 20 is fixed (relative). Therefore, it is possible to use an Ag—Sn solder having a smaller fixing force than that of the Au—Sn solder.

As shown in FIGS. 1 to 3, the guide wire of the present embodiment is filled with a cured resin 40 inside the coil spring 20, and the outer periphery of the coil spring 20 and the resin layer 40 </ b> A made of the cured resin 40. The tip is covered.
A hydrophilic resin layer 50 is laminated on the surface of the resin layer 40A.

  By filling the inside of the coil spring 20 with the cured resin 40, the core wire 10 and the coil spring 20 are integrated, the torque transmission performance of the guide wire is greatly improved, and the core wire 10 has a large diameter on the proximal end side. The rotational torque transmitted from the portion 14 is reliably transmitted to the distal end of the coil spring 20 integrated with the distal end side small diameter portion 11.

  Further, since the hydrophilic resin layer 50 is formed on the outer periphery of the coil spring 20 via the resin layer 40A (undercoat layer), the hydrophilic resin layer 50 is firmly fixed and lubricated by the hydrophilic resin. Can be stably expressed.

Here, the cured resin 40 that fills the inside of the coil spring 20 and forms the resin layer 40A that covers the outer periphery of the coil spring 20 has good adhesion to both the coil spring 20 and the hydrophilic resin. Specific examples include urethane acrylate resins, polyurethane resins, silicone resins, epoxy resins, acrylic resins, nylon resins, and other photo-curable resins or thermosetting resin cured products. .
The film thickness of the resin layer 40A covering the outer periphery and the tip of the coil spring 20 is, for example, 1 to 100 μm, and preferably 3 to 10 μm.

As the resin constituting the hydrophilic resin layer laminated on the surface of the resin layer 40A, any resin used in the medical device field can be used.
The thickness of the hydrophilic resin layer 50 is, for example, 1 to 30 μm, preferably 3 to 19 μm.

  As a method of filling the cured resin 40 and forming the resin layer 40A and a method of forming the hydrophilic resin 50 by lamination, for example, the coil spring 20 attached to the core wire 10 is immersed in the curable resin to immerse the coil spring 20. The inside is filled with a curable resin, and a resin layer is formed on the surface of the coil spring 20, and this is thermally cured or photocured to obtain a cured resin 40 (resin layer 40A), and then on the surface of the resin layer 40A. A method of applying a hydrophilic resin by an appropriate means can be mentioned.

According to the guide wire 1 of the present embodiment, since the Au—Sn solder is used as the solder for fixing the tip of the coil spring 20 to the core wire 10, the proximal end side large diameter portion 14 of the core wire 10. Strength of the coil spring to the core wire (the distal end side small diameter portion 11) despite the fact that the outer diameter of the wire is as thin as 0.012 inches or less and the length of the tip rigid portion is as short as 0.3 to 0.4 mm. Is sufficiently high, and even if a tensile force is applied between the coil spring 20 and the core wire 10, the core wire 10 is not pulled out.
And since the length of the tip rigid portion is as short as 0.3 to 0.4 mm, the shaping length can be shortened, and as a result, the frictional resistance can be sufficiently reduced during operation in the microchannel. it can. In addition, treatment in a narrow region that cannot be performed using a conventional guide wire is also possible.

Further, since the inside of the coil spring 20 is filled with the cured resin 40, the core wire 10 and the coil spring 20 can be integrated, and the torque transmission performance and operability of the guide wire 1 can be significantly improved. it can.
Further, since the hydrophilic resin layer 50 is laminated on the outer periphery of the coil spring 20 via the resin layer 40A of the cured resin 40, the lubricity by the hydrophilic resin can be stably expressed.

  Further, since the coil spring 20 includes the front end side closely wound portion 21 and the rear end side loosely wound portion 22, good contrast (visibility) can be expressed in the front end side closely wound portion 21.

FIG. 4A shows a state where the tip of the guide wire of the present invention (coil spring outer diameter = 0.010 inches) is shaped. The length of the rigid portion of the guide wire is 0.35 mm (the penetration range of the Au—Sn solder is equivalent to 2 pitches of the coil spring), and the shaping length is 0.32 mm on the inner length (L ₅₁ ). The outer length (L ₅₂ ) is 0.53 mm.
FIG. 4B shows a state where the tip of a conventional guide wire (coil spring outer diameter = 0.010 inch) is shaped. The length of the rigid portion of the guide wire is 0.8 mm (the penetration range of the Ag—Sn solder is equivalent to 6 pitches of the coil spring), and the shaping length is 0.82 mm on the inner length (L ₅₁ ). The outer length (L ₅₂ ) is 1.01 mm.

<Example 1>
(1) Preparation of guide wire:
A coil spring is mounted on the distal end side small diameter portion of the core wire (core wire made of stainless steel coated with PTFE) whose outer diameter of the proximal end side large diameter portion is 0.010 inch, and is shown in FIGS. Thirteen guide wires of the present invention having the above-described structure were produced.
Here, the coil spring has a coil outer diameter (D ₂ ) of 0.010 inches, a length (L ₂ ) of 115 mm, and a length of the closely wound end (coil pitch is 1.0 times the coil wire diameter). (L ₂₁ ) was 30 mm, and the rear end side loosely wound portion (coil pitch was 2.0 times the coil wire diameter) having a length (L ₂₂ ) of 85 mm was used.
Further, the tip and middle portions of the coil spring were fixed to the core wire using Au—Sn solder, and the rear end of the coil spring was fixed to the core wire using Ag—Sn solder.
In each of the 13 guide wires, the coil pitch number (abbreviated as “pitch number” in Table 1) corresponding to the region (length) in which the solder has penetrated inside the coil is any one of 1 to 3. I made it. Table 1 shows the length of the tip rigid portion.
In addition, after the coil spring is mounted on the core wire, the inside of the coil spring is filled with a cured resin (urethane acrylate resin), and a resin layer is formed on the outer periphery of the coil spring from the polyethylene oxide on the surface of the resin layer. The resulting hydrophilic resin layer was laminated.

(2) Guidewire evaluation:
The minimum shaping length (minimum bendable length) was measured for each of the 13 guide wires obtained by the above (1).
The measurement of the minimum shaping length was performed for the inner length (L ₅₁ ) and the outer length (L ₅₂ ) as shown in FIG.
Further, a tensile force was applied between the coil spring and the core wire, and the fractured portion was observed to evaluate the fixing property. The evaluation criteria were “◯” when the distal end side small diameter portion of the core wire was broken, and “X” when peeling occurred between the coil spring or the distal end side small diameter portion and the solder. If there is even one “x”, it cannot be made into a product. The results are also shown in Table 1 below.

<Comparative Example 1>
Thirteen comparative guidewires were made using Ag-Sn solder as solder for fixing the tip, middle and rear ends of the coil spring to the core wire.
In each of the 13 guide wires, the coil pitch number (abbreviated as “pitch number” in Table 2) corresponding to the region (length) in which the solder has penetrated inside the coil is any one of 1 to 3. I made it. Table 2 shows the length of the rigid portion of the tip.
Further, after the coil spring is attached to the core wire, in the same manner as in Example 1, the inside of the coil spring is filled with a cured resin, and a resin layer made of a cured resin is formed on the outer periphery of the coil spring. A hydrophilic resin layer was laminated.
For each of the 13 guide wires obtained as described above, the minimum shaping length was measured in the same manner as in Example 1 to evaluate the adhesion. The results are also shown in Table 2 below.
The comparative example 1 is a comparative example in which no Au—Sn solder was used when fixing the tip of the coil spring to the core wire.

<Comparative Examples 2-6>
Using Ag-Sn solder as the solder to fix the tip, middle and rear ends of the coil spring to the core wire, and making a comparative guide wire with a tip rigid portion exceeding 0.5 mm did.
In each of the guide wires, the coil pitch number (abbreviated as “pitch number” in Table 3) corresponding to the region (length) in which the solder penetrated into the coil was set to any one of 4-8. Table 3 shows the length of the tip rigid portion.
Further, after the coil spring is attached to the core wire, in the same manner as in Example 1, the inside of the coil spring is filled with a cured resin, and a resin layer made of a cured resin is formed on the outer periphery of the coil spring. A hydrophilic resin layer was laminated.
For each of the guide wires obtained as described above, the minimum shaping length was measured in the same manner as in Example 1. The results are also shown in Table 1 below.

DESCRIPTION OF SYMBOLS 10 Core wire 11 Distal end side small diameter part 13 Tapered part 14 Proximal end side large diameter part 20 Coil spring 21 Front end side densely wound part 22 Rear end side loosely wound part 31 Au-Sn series solder 32 Au-Sn series solder 33 Ag -Sn-based solder 40 Cured resin 40A Resin layer 50 Hydrophilic resin layer

Claims (7)

A core wire having a distal end side small diameter portion and a proximal end side large diameter portion having an outer diameter larger than that of the distal end side small diameter portion;
A medical guide wire having a coil spring attached to the outer periphery of the small-diameter portion on the distal end side of the core wire along the axial direction, and having a coil spring fixed to the core wire at least at the front end portion and the rear end portion;
The outer diameter of the large diameter portion on the proximal end side of the core wire and the coil outer diameter of the coil spring are both 0.012 inches or less,
The tip of the coil spring is fixed to the core wire with Au-Sn solder,
A medical guide wire, wherein the length of the tip rigid portion made of Au-Sn solder is 0.1 to 0.5 mm.   2. The medical guide wire according to claim 1, wherein an outer diameter of the proximal end side large diameter portion of the core wire and a coil outer diameter of the coil spring are both 0.010 inches or less. The coil pitch at the tip of the coil spring is 1.0 to 1.8 times the coil wire diameter,
The medical guide wire according to claim 1 or 2, wherein Au-Sn solder penetrates into the coil in a range corresponding to 1 to 3 pitches of the coil spring. The inside of the coil spring is filled with resin, a resin layer made of the resin is formed on the outer periphery of the coil spring, and a hydrophilic resin layer is laminated on the surface of the resin layer,
The medical guide wire according to any one of claims 1 to 3, wherein a water repellent resin layer is formed on a surface of the core wire.   The coil spring includes a front end side closely wound portion having a coil pitch of 1.0 to 1.8 times the coil wire diameter, and a rear end side loosely wound portion having a coil pitch exceeding 1.8 times the coil wire diameter. The medical guide wire according to claim 1, wherein the medical guide wire is a medical guide wire.   6. The medical use according to claim 5, wherein an intermediate portion including the front end side closely wound portion and the rear end side loosely wound portion of the coil spring is fixed to the core wire with Au-Sn solder. Guide wire.   The medical guide wire according to any one of claims 1 to 6, wherein the core wire is made of stainless steel.

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