JP3586024B2 - Medical guidewire - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a medical guidewire used for introducing a catheter into a cardiovascular system.
[0002]
[Prior art]
For the purpose of angiography, insert a catheter with a very thin flexible tube into a blood vessel, or when inserting a balloon catheter into a blood vessel for treatment of an occluded area of a coronary artery, ensure that the catheter is inserted safely. In order to achieve this, a medical guide wire made of a flexible wire is used, and there are known examples disclosed in Japanese Patent Publication Nos. 4-25024 and 4-292175.
[0003]
That is, since a known medical guidewire (hereinafter, simply referred to as a guidewire) is inserted from a distal end portion into a blood vessel having a meandering complicated long path, the whole has flexible flexibility and a traveling direction. Vertical load resistance (buckling resistance) is required for the load, and the distal end that leads the insertion process must have a soft distal head that smoothly leads without damaging the blood vessel wall. For intravascular insertion, push in while rotating the part that has been inserted from the distal end and out of the body as necessary, and adjust the position of the distal end inserted into the blood vessel (when inserting the distal end into the branch blood vessel, When adjusting the direction to guide the distal end to the branch blood vessel) or when pulling it out of the blood vessel, it may be pulled out while rotating it to reduce the pull-out resistance. body High mechanical properties obtained by having both the steering of adjusting operating the tip in the blood vessel from becomes indispensable.
[0004]
Therefore, a guide wire that satisfies the above-mentioned necessary characteristics is provided at the tip of the core material of a long and extremely fine wire (for example, a stainless wire having a diameter of about 0.35 mm and a length of about 1,300 mm). It has a basic structure in which a distal end head of a rounded-shaped soft body is attached, a slightly length of a core material following the distal end is formed in a reduced diameter portion, and a coil spring is fitted and mounted. The coil spring is a separate spring consisting of a coil spring made of a radiopaque material such as a platinum-nickel alloy wire in the first half and a coil spring made of a radiolucent material such as a stainless wire in the second half. A coil spring is used, and the tip of the coil spring fitting is plastically deformed into a `` U-shape '' with a fingertip as necessary to facilitate insertion into a blood vessel and sequentially insert from the tip, The required treatment is performed while confirming the position and direction of the tip inside the blood vessel by radiation from outside the body.
[0005]
[Problems to be solved by the invention]
With the above conventional guide wire, the bending stress corresponding to the wire material of the coil spring remains due to the plastic deformation of the above-mentioned "U-shape", and the distal end portion fitted with the coil spring is pulled out from the blood vessel. Sometimes it receives strong pull resistance. That is, for example, the guide wire inserted into the narrowed portion of the blood vessel strongly engages the distal end portion of the guide wire with the narrowed blood vessel, so that the withdrawal resistance becomes considerably large and the coil spring is inserted into the narrowed portion of the blood vessel. When the middle of the coil spring engages, rotate the guide wire in the direction in which the coil diameter of the coil spring near the tip from the engagement point decreases (in the direction opposite to the winding direction from the lower end to the upper end of the coil spring). Since the operation of passing the engagement point is performed by rotating the wire main body), the pulling load and the torsional load due to the rotation are carried by the reduced diameter portion of the wire main body and the coil spring.
[0006]
Therefore, the coil spring and the core made of the ultrafine wire rarely cause breakage due to, for example, microscopic defects and component segregation on the material due to the bending stress and the carried load, and welding of dissimilar metals. The coil spring consisting of the connection is separated from the connection point, the tip part is separated from the wire main body, and even if the risk of being left in the blood vessel is extremely small, there is a difficulty that it can not be declared that it does not exist .
[0007]
The present invention is to solve the above-mentioned disadvantages of the prior art, and to provide a guide wire that can eliminate the risk as much as possible.
[0008]
The guide wire of the present invention that solves the above technical problem is provided with a distal head at a distal end of a wire mainly made of a flexible ultrafine wire, and formed at a small portion of the main wire following the distal end to form the distal head. A medical guide wire in which a coil spring made of a connection of a dissimilar metal of a radiopaque material made of stainless steel on the front end side and a radiopaque material made on the rear end side is fitted to a contracted portion having a large degree of compaction in the direction of A clearance is provided between an inner periphery of the coil spring and an outer periphery of the reduced portion mainly composed of the wire, a tip is fixed to the tip head, and a coil spring made of the stainless steel is provided rearward from a connection point of the dissimilar metal. A safety wire connected and locked to the outer periphery of the wire main body inside the clearance is provided in the clearance, and the safety wire has the same winding direction and twisting direction of the coil spring, and It has a structure "consisting of a twisted wire of the line shape.
[0009]
That is, the guide wire of the present invention is provided with a safety wire for connecting the intermediate portion between the distal end head and the wire main body in the clearance between the coil spring and the main wire, and the distal end portion of the guide wire is placed in the blood vessel due to an inevitable cause. If the guide wire is pulled out of the blood vessel without being separated from the main body of the wire even when the wire is broken or connected and separated, the torsion / pull load received by the distal end of the guide wire may be reduced. The structure is characterized in that the part is carried on the safety wire.
[0010]
The safety wire is made of a stranded wire or solid wire having a diameter of about 0.06 mm, and the tip and the rear end (or the middle) are connected to the tip head by any means such as brazing or caulking. In addition to being connected and connected to the wire main body, the connected and fixed intermediate portion is formed in a meandering shape so as not to impair the flexibility of the guide wire, and the extension on the pulling side when bending around the center of the wire main body as a neutral axis. Or in the case of the above-mentioned stranded wire, the twist direction is made the same as the winding direction of the coil spring, and when inserting and pulling out the guide wire by turning it in the winding direction of the coil spring, the wire is mainly formed by the rotation. A mode such as preventing the twisted wire from being loosened by twisting is adopted.
[0011]
[Action]
Since the guide wire of the present invention includes the above-described safety wire, even if the distal end portion of the guide wire inserted into the blood vessel is damaged, the contacted portion is separated from the main wire and is left behind. It is extremely low. When the wire is pulled out of a meandering blood vessel by a guide wire in a normal state, a part of the pulling-out load and the torsion load is shared by the safety wire. The risk of separation of the tip portion due to load / torsion load can be reduced to zero as much as possible.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
The medical guidewire of the present invention is implemented as follows.
[0013]
【Example】
A medical guidewire 1 according to an embodiment of the present invention will be described with reference to FIG. That is, a soft hemispherical tip head 3 is provided at the tip of the ultrafine stainless steel wire main body 2, and the diameter of the wire main body 2 following the tip head 3 is reduced to a rectangular cross-sectional shape and narrowed. The guide wire 1 is formed with a coil spring 5 having a diameter substantially equal to that of the distal end head 3 and having a distal end fixed to the distal end head 3. , A minute clearance 6 is provided, and a safety wire 10 is provided in the clearance 6 .
[0014]
More specifically, as shown in FIG. 1C, the safety wire 10 is made of a known stranded wire in which seven ultrafine wires 8 are twisted, and has a meandering shape that gently meanders in the longitudinal direction of the wire. Have. The tip 9 of the safety wire 10 is attached and fixed to the tip head 3 by any means such as caulking or brazing, and the rear end 11 (or the middle) of the safety wire 10 is wire-bonded by a brazing portion 12. It is connected to the main body 2 and is provided inside the clearance 6 substantially in parallel with the reduced diameter portion 4.
[0015]
Note that the reduced portion 4 of this embodiment has a primary reduced portion 4A having a small degree of reduction at the rear end side of the wire main body 2 and a secondary reduced portion having a large degree of reduction at the distal end side of the wire main body 2. The lower end 11 of the safety wire 10 is connected to the primary deformed portion 4A having a large cross-sectional shape and excellent mechanical strength because of the technical purpose described above.
[0016]
The wire main body 2 of the guide wire 1 of this embodiment is a stainless wire having a total length of about 1,300 mm and a diameter of about 0.3 mm, and the safety wire 10 has seven 0.02 mm diameters. The wire strand 8 is S-twisted at a pitch of 0.5 mm, has a wire diameter of 0.06 mm, has the same twist direction as the coil spring 5, and has a total length of about 30 mm. The coil spring 5 is the same as the conventional structure in which the coil spring of the platinum-nickel alloy wire in the first half near the distal end head 3 and the coil spring of the second half of the stainless wire are connected at the joint 14.
[0017]
The guide wire 1 of the above-described embodiment of FIG. 1 has the above-described action, and the secondary withdrawn portion 4B serving as a weak point of mechanical strength is divided by the strong pull-out resistance from the blood vessel, or the coil spring 5 is Even if the safety wire 10 is cut off from the junction point 14, the safety wire 10 connects and locks the cut portion to the wire main body 2, so that the risk of being left in the blood vessel is almost zero. In the normal state of the guide wire 1 where the division does not occur, the safety wire 10 shares a part of the pull-out load and the torsion load received by the contracted portion 4B and the coil spring 5, so that the risk of the division is further reduced. Therefore, the safety is particularly improved as compared with the conventional structure without the safety wire.
[0018]
Since the safety wire 10 of this embodiment has a twisted wire configuration having the same twist direction as the coil direction of the coil spring 5, the safety wire 10 is twisted by the turning operation of the wire main body 2 (when inserted into a blood vessel, the tip is The wire main body 2 is rotated in the coil winding direction of the coil spring 5 when viewed from the outside, and the rotation resistance reduces the diameter of the coil spring to facilitate insertion.) The twist of the safety wire 10 is not loosened.
[0019]
Since the safety wire 10 has the above-mentioned meandering shape, when the distal end portion is plastically deformed into a “U-shape” using the center line 13 of the wire main body 2 as a neutral axis at the time of insertion into a blood vessel, the pulling side of the bending deformation Even if the safety wire 10 is present, the meandering shape of the guide wire 1 compensates for the pulling allowance, so that there is almost no resistance to bending deformation, and the flexibility of the guide wire 1 when the wire is advanced into a meandering blood vessel. There is no risk of impairing the properties, and the necessary mechanical properties of the guidewire 1 can be satisfactorily secured.
[0020]
【The invention's effect】
As described above, the medical guidewire according to the present invention has a remarkable effect of preventing the remaining in the blood vessel at the distal end portion with a probability close to zero as much as possible, and particularly improving the performance and safety of the guidewire. .
[Brief description of the drawings]
1A and 1B show a medical guidewire according to an embodiment of the present invention, wherein FIG. 1A is a front view thereof, FIG. 1B is a DD sectional view of FIG. 1A, and FIG. Description]
DESCRIPTION OF SYMBOLS 1 Medical guide wire 2 Wire main body 3 Tip head 4A Primary reduced diameter part 4B Secondary reduced diameter part 5 Coil spring 6 Clearance 8 Wire strand 9 Safety wire tip 10 Safety wire 11 Safety wire rear end 12 Brazed part

Claims (1)

With a distal end at the distal end of a wire mainly composed of a flexible ultrafine wire, a reduced portion formed in a small portion of the wire main body following the distal end to greatly reduce the degree of compression toward the distal end head. A medical guidewire fitted with a coil spring made of a combination of dissimilar metals of a radiolucent material made of stainless steel at the rear end side and a radiopaque material at the rear end side. A safety is provided in which a clearance is provided between the outer peripheries of the parts, the front end is fixed to the front end head, and the rear end is connected to the outer periphery of the wire main body inside the coil spring made of stainless steel so as to be behind the connection point of the dissimilar metal. comprising a wire in said clearance, further the safety wire, the a lay direction winding direction of the coil spring in the same, and a medical gas, wherein structure consisting of twisted wire serpentine Dowaiya.

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