JPH0224548B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a catheter guide wire that can guide a catheter.

[Conventional technology]

FIGS. 1 and 2 are cross-sectional views showing a conventional catheter guide wire 1. FIG. The guide wire 1 has an inner core 2 formed by integrating a main body inner core part 2A and a distal inner core part 2B, and the entire length of the inner core 2 is
As shown in the figure, the spring 4 is covered with a synthetic resin coating 3.
Here, the inner core 2 is formed of an elastic metal body such as stainless steel wire or piano wire. As shown in FIG. 1, at both ends of the inner core 2 there are bulges 2C that hold the spring 4 and allow the position of the tip of the guide wire 1 traveling inside the blood vessel to be detected by X-rays. We are prepared.

The above-mentioned guide wire 1 has a main body side inner core part 2A, for example, by making the cross-sectional area of the main body side inner core part 2A relatively large, and by making the cross-sectional area of the distal end side inner core part 2B, for example, relatively small. The main body portion 1A comprising the main body portion 1A is relatively rigid, and the distal end portion 1B comprising the distal inner core portion 2B is relatively flexible.
Therefore, according to the guide wire 1, (1) in order to facilitate the introduction of the catheter into the target blood vessel site, the guide wire 1 is compared with the bent portions of various shapes formed at the distal end of the catheter. (2) By advancing the guide wire 1 into the blood vessel in a straight state under the insertion of the main body portion 1A having high rigidity, and (2) by advancing the guide wire 1 through the blood vessel with the distal end portion 1B of the guide wire 1 ahead of the distal end portion of the catheter. This is intended to prevent damage to the inner walls of blood vessels caused by the tip of the catheter.

[Problem to be solved by the invention]

At this time, the main body portion of the conventional guide wire 1 which is operated by hand has its main body side inner core portion 2A formed of the general elastic metal body as described above. For this reason, the main body is easily buckled or torsionally deformed when operated at hand, and has poor restorability after buckling or torsionally deforming, making it difficult to smoothly introduce the device.

In addition, the distal end of the conventional guide wire 1 that is introduced and placed in a predetermined site such as a blood vessel also has a distal inner core portion 2.
B is made of a general elastic metal body as described above. For this reason, it is difficult to ensure that the distal end has sufficient flexibility and resilience against deformation so that it can be inserted into a predetermined site of a blood vessel or the like while conforming to its shape without damaging the tortuous blood vessel or the like. Furthermore, it is difficult to ensure that the distal end has adequate rebound resilience necessary for indwelling in a predetermined site such as a blood vessel.

The present invention aims at the following (A) and (B).

(A) To provide a guide wire whose main body is difficult to buckle or twist when operated at hand, and even if it should buckle or twist, it can be easily restored to its original state and facilitates the introduction operation.

(B) The distal end has sufficient flexibility and resilience against deformation so that it can be inserted into a predetermined site such as a blood vessel while conforming to its shape without damaging tortuous blood vessels, etc.;
Further, it is an object of the present invention to provide a guidewire having appropriate rebound resilience necessary for placement in a predetermined site such as a blood vessel.

[Means to solve the problem]

The present invention provides a guide wire for a catheter in which an inner core is formed by a main body side inner core part and a distal end side inner core part, and substantially the entire inner core is covered with a covering part. At least one of the inner core portion and the distal inner core portion is formed of a superelastic metal body, and the outer diameter of the covering portion is made the same in the longitudinal direction.

[Effect]

According to the present invention, there is provided a guide wire in which the outer diameter of the covering portion that covers substantially the entire inner core is the same in the longitudinal direction, and the outer diameter of the covering portion that covers substantially the entire inner core is the same in the longitudinal direction. By forming it from an elastic metal body, there are the following effects.

When the main body side inner core portion is formed of a superelastic metal body, the main body portion can be provided with elastic strain characteristics having relatively high buckling strength. This means that the above-mentioned object (A) of the present invention can be achieved.

When the distal end inner core portion is formed of a superelastic metal body, the distal end portion can be provided with an elastic strain characteristic that allows a relatively large displacement under a constant stress and allows recovery. This means that the above-mentioned object (B) of the present invention can be achieved.

〔Example〕

FIG. 3 is a sectional view showing a catheter guide wire 10 according to an embodiment of the present invention, and FIGS. 4A to 4D are sectional views taken along lines A to A to D-D in FIG. 3.

The guide wire 10 has an inner core 11 consisting of a main body inner core part 11A and a distal inner core part 11B. is formed.

At least the tip side inner core portion 11B of the inner core 11
is formed of a superelastic metal body, and to explain specifically, the inner core 11 has a main body side inner core part 11A with a circular cross section, a tip side inner core part 11B with a plate-shaped cross section, and a tapered part 11C. TiNi alloy with 49-58 atomic% Ni, Cu-Zn alloy with 38.5-41.5% by weight Zn, Cu-Zn- alloy with several weight%
It is made of a superelastic (pseudoelastic) metal body such as X alloy (X=Be, Si, Sn, Al, Ga), Ni-Al alloy with 36 to 38 atomic percent Al.

Further, the guide wire 10 has a main body side inner core portion 1
The cross-sectional area of 1A is relatively large, and the inner core part 11 on the tip side
By making the cross-sectional area of B relatively small, the main body portion 10A having the main body side inner core portion 11A has relatively high rigidity, and the distal end portion having the tip side inner core portion 11B has a relatively high rigidity. The portion 10B is made relatively flexible. Here, the tapered portion 11C has a structure in which the rigidity changes gradually at the connection portion between the main body side inner core portion 11A and the distal side inner core portion 11B, so that bending of the guide wire 10 at the connection portion can be prevented. There is. Further, a bulging portion 11D is integrated into the most distal end of the distal inner core portion 11B, so that the position of the distal end of the guide wire 10 advancing within the blood vessel can be reliably detected by X-rays. Note that the cross-sectional shape of the distal inner core portion 11B is not limited to a plate shape, but may be circular,
It may be triangular, polygonal, etc., but if it is plate-shaped, the difference in the length of expansion and contraction between the front and back surfaces during bending under the same cross-sectional area condition is minimized, and the tip 1
Allows for more flexible deformation of 0B.

The covering portion 12 is made of polyethylene, silicone,
It is made of synthetic resin such as nylon, urethane, or Teflon, and has the same outer diameter without any unevenness in the longitudinal direction. The covering portion 12 is bonded to the inner core 11 on the side opposite to the distal end, that is, at the proximal end of the guidewire 10 . For example, when the covering section 12 is formed of a hollow tube, it is not bonded to the inner core 11 over almost the entire length except for the proximal end, and is restrained by the bonding to the inner core 11 when the guide wire 10 is bent. The guide wire 10 can freely move relative to the inner core 11 without being deformed, and in particular, allows the distal end portion 10B of the guide wire 10 to be flexibly deformed.

In addition, the covering part in the present invention is shown in FIGS. 4A to 4D.
As shown as the covering portion 12A in FIGS. 5A to 5D, polyethylene, silicone, nylon,
The surface of the inner core 11 may be coated with a polymer such as urethane. Also in this case, it is preferable that the covering portion 12A is not bonded to at least the distal inner core portion 11B, and the guide wire 10
However, in the guidewire of the present invention, the form of bonding between the inner core and the covering portion is not particularly limited, and one or both ends or the entire guidewire may be bonded. may have been done.

FIG. 6 is a diagram showing the stress-strain characteristics of a superelastic metal by a solid line and the stress-strain characteristics of a general elastic metal by a broken line. That is,
Superelastic metals have the following characteristics: (1) the recoverable elastic strain is large, reaching several percent to several percent, and (2) the magnitude of the load does not change even if the strain increases. Therefore, since the guide wire 10 has its main body side inner core portion 11A made of a superelastic metal body, the main body portion 10A has elastic strain characteristics with relatively high buckling strength. becomes. In addition, since the guide wire 10 has its distal inner core portion 11B made of a superelastic metal body, the distal end portion 10B has an elastic strain that can change relatively greatly under a constant stress and can be restored. It will have the following characteristics.

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

The guide wire 10 has variously shaped bent portions formed at the distal end of the catheter, and is straightened under the insertion of its relatively rigid body portion 10A.
This allows the catheter to advance smoothly within the blood vessel. In addition, the guide wire 10 advances within the blood vessel with its distal end 10B ahead of the distal end of the catheter, thereby making it possible to prevent damage to the inner wall of the blood vessel caused by the distal end of the catheter.

Here, the guide wire 10 has elastic strain characteristics with relatively high buckling strength in its main body portion 10A. Therefore, when inserting the guide wire 10 into a catheter or blood vessel, the main body 10
A is difficult to buckle or twist when operated at hand,
Even if it buckles or twists, it will easily recover,
Installation operations can be made smoother.

Further, since the guide wire 10 has the distal end inner core portion 11B made of a superelastic metal body, the distal end portion 10B has an elastic strain characteristic that allows a relatively large displacement under a constant stress and restores the distal end portion 10B. Therefore, the distal end portion 10B should have sufficient flexibility and resilience against deformation so that it can be inserted into a predetermined site such as a blood vessel while conforming to its shape without damaging the tortuous blood vessel, etc., and be careful about the predetermined site such as a blood vessel. It has the appropriate repulsion elasticity necessary for

In addition, in the guide wire 10, if the sheathing portion 12 is formed by coating with synthetic resin, a part of the sheathing portion 12 may peel off, or a foreign substance such as a blood clot may be present on the surface of the sheathing portion 12. No binding occurs. Therefore, according to the guide wire 10 coated with the above synthetic resin,
High safety can be ensured without causing blood flow disorders such as vascular occlusion.

In a preferred embodiment of the guide wire 10, the covering portion 12 is not bonded to the inner core 11 over substantially the entire length except for its proximal end, and therefore, as described above, the covering portion 12 is not bonded to the inner core 11. When bent, it is not restricted by adhesion to the inner core 11,
It is possible to move freely relative to the inner core 11, and particularly to improve the flexibility of the distal end portion 10B of the guide wire 10. In addition, the guide wire 1
0 has a covering part 12 made of a hollow tube, when the guide wire 10 is bent, the covering part 1
2 has good deformability, especially the guide wire 10.
It becomes possible to improve the flexibility of the tip portion 10B.

FIG. 7 is a sectional view showing a catheter guide wire 20 according to a modified example of the guide wire 10 described above. This guide wire 20 consists of an inner core 21 and a covering portion 22. This guide wire 20
differs from the guide wire 10 in that the inner core 21
The main body side inner core part 21A and the tip side inner core part 2 forming the
1B has the same cross-sectional area and cross-sectional shape in the longitudinal direction. Therefore, in this guide wire 20, the mechanical properties of the distal end and the main body can be made to be mutually different, for example, by changing the heat treatment conditions applied to the main body inner core part 21A and the distal inner core part 21B. This makes it possible to obtain a relatively rigid body portion and a relatively flexible tip portion.

In each of the above embodiments, the inner cores 11 and 12 are entirely formed of a superelastic metal body. However, in the present invention, even if the tip side inner core made of a superelastic metal body is integrated with the main body side inner core made of another general elastic metal body by press-fitting, caulking, etc. good. Further, the main body side inner core made of a superelastic metal body may be integrated with the tip side inner core made of another general elastic metal body by press fitting, caulking, etc.

Further, in carrying out the present invention, the covering portion is not limited to a synthetic resin body, but may also be a coiled body.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to obtain a guidewire whose main body is difficult to buckle or torsionally deform when operated at hand, and even if it should be buckled or torsionally deformed, it can be easily restored to its original state, thereby facilitating the introduction operation. Can be done.

Further, according to the present invention, the distal end portion has sufficient flexibility and resilience against deformation so that it can be inserted into a predetermined site such as a blood vessel while conforming to its shape without damaging a tortuous blood vessel, etc., and has sufficient flexibility and resilience against deformation. It is possible to obtain a guidewire with appropriate repulsion resilience necessary for indwelling.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a conventional catheter guide wire, FIG. 2 is an enlarged sectional view of the main part of FIG. 1, and FIG. 3 is a catheter guide according to an embodiment of the present invention. Cross-sectional views showing wires, Figures 4A-D are cross-sectional views taken along line A-A in Figure 3~
A sectional view taken along the line D-D, FIGS. 5A to 5D are sectional views corresponding to FIGS. 4A to D in modified examples of the present invention, and FIG. - Strain diagram; FIG. 7 is a sectional view showing a guide wire according to a modification of the present invention. 10,20... Catheter guide wire, 1
0A...Body part, 10B...Tip part, 11, 21
...Inner core, 11A, 21A...Inner core on main body side, 1
1B, 21B...Tip side inner core part, 12, 12A,
22... Covering part.

Claims (1)

[Scope of Claims] 1. A guide wire for a catheter in which an inner core is formed by an inner core portion on the main body side and an inner core portion on the distal end side, and substantially the entire inner core is covered with a covering portion. A guide wire for a catheter, characterized in that at least either the main body side inner core portion or the distal side inner core portion is formed of a superelastic metal body, and the outer diameter of the covering portion is made the same in the longitudinal direction. 2. The cross-sectional area of at least a part of the distal inner core section is made smaller than the cross-sectional area of the main body inner core section, and the cross-sectional area between the main body inner core section and the distal inner core section is made smaller than the cross-sectional area of the inner core section on the main body side. The guide wire for a catheter according to claim 1, which continuously contracts from the core toward the distal inner core. 3 Claim 1 in which the covering portion is a hollow tube
The guide wire for a catheter according to item 1 or 2. 4. The guide wire for a catheter according to claim 1 or 2, wherein the covering portion is made of a coating thin film.